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  • 1990-1994  (236)
  • 1965-1969
  • 1860-1869
  • 1991  (236)
  • Industrial Chemistry and Chemical Engineering  (212)
  • Insulin
  • 1
    Electronic Resource
    Electronic Resource
    Effect of hyperkalemia on insulin secretion (1991)
    Springer
    Cellular and molecular life sciences 47 (1991), S. 270-272 
    Details
    ISSN: 1420-9071
    Keywords: Insulin ; potassium ; hyperkalemia ; portal vein ; glucose
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The effect of hyperkalemia on insulin secretion remains undefined. We evaluated portal and peripheral insulin levels in anesthetized dogs after infusions of KCl. The mean maximal increase in peripheral plasma potassium at infusion rates of 0.2 mEq/kg/h was 0.68±0.20 mEq/l. There were no significant increases in either portal or peripheral insulin levels. In contrast, in six dogs whose plasma potassium concentration increased in each case by more than 2.0 mEq/l (infusion rate of 0.5 mEq/kg/h), portal insulin levels increased fivefold (p〈0.05). We conclude that only marked increases in plasma potassium concentration stimulate pancreatic insulin secretion.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01958157
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  • 2
    Electronic Resource
    Electronic Resource
    Serum levels of glucose, insulin, and C-peptide during long-term D-ribose administration in man (1991)
    Springer
    Journal of molecular medicine 69 (1991), S. 31-36 
    Details
    ISSN: 1432-1440
    Keywords: (D-)ribose ; Glucose ; Insulin ; C-peptide
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary D-ribose was given orally and/or intravenously to nine healthy subjects at doses ranging from 83.3 to 222.2 mg/kg per hour for at least four hours. The serum ribose level increased in a dose-dependent manner to maximum concentrations of 75 to 85 mg/dl. The serum glucose level decreased after the beginning of continuous ribose administration and was reduced as long as ribose was being administered. The oral or intravenous administration of 166.7 mg/kg per hour of ribose resulted in a 25% decrease in serum glucose. Higher intravenous doses of ribose did not provoke a further decrease in serum glucose concentration. Oral administration of 166.7 mg/kg per hour led to an increase in serum insulin concentrations from a mean of 8.4 (range 6.4–11.5) to 10.4 (range 6.3–15.4) μU/ml (p〈0.05). In contrast, intravenous administration did not change serum insulin concentrations significantly. The serum c-peptide concentration remained unchanged regardless of treatment. We conclude that the variations in plasma insulin concentrations do not account for the observed decrease in mean serum glucose concentrations accompanying D-ribose administration.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01649054
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  • 3
    Electronic Resource
    Electronic Resource
    Different aetiologies of Type 2 (non-insulin-dependent) diabetes mellitus in obese and non-obese subjects (1991)
    Springer
    Diabetologia 34 (1991), S. 483-487 
    Details
    ISSN: 1432-0428
    Keywords: Insulin ; glucose ; obesity ; glucose disposal ; insulin secretion
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Insulin responses to intravenous glucose infusion and glucose utilization during hyperinsulinaemic euglycaemic clamp were determined in a large homogeneous group of 65-year-old male subjects. Twenty-eight had untreated Type 2 (non-insulin-dependent) diabetes mellitus and the remaining 44 control subjects had a normal glucose tolerance. Diabetic patients with abdominal obesity displayed peripheral insulin resistance in combination with defective insulin secretion, whereas non-obese diabetic patients showed only a secretory defect. Thus, Type 2 diabetes in obese and non-obese elderly male subjects may take two forms where the cause of hyperglycaemia differs.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00403284
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  • 4
    Electronic Resource
    Electronic Resource
    No glucotoxicity after 53 hours of 6.0 mmol/l hyperglycaemia in normal man (1991)
    Springer
    Diabetologia 34 (1991), S. 570-575 
    Details
    ISSN: 1432-0428
    Keywords: Insulin ; glucose ; insulin resistance ; man ; glucotoxicity
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary In vitro and in vivo studies have suggested that metabolic deterioration can be induced by hyperglycaemia per se. The effect of 53 h of 2.2 mg glucose · kg ideal body weight−1· min−1 was examined in four normal male subjects. This produced overnight hyperglycaemia of 6.0 mmol/l on the two nights of the study compared with 4.7 mmol/l on the control night (p〈0.05). In response there was a sustained, two-fold increase in basal plasma insulin (p〈0.005) and C-peptide (p〈0.05) levels. After two days of hyperglycaemia an increased Beta-cell response was demonstrated in response to an additional glucose infusion stimulus (estimated Beta-cell function median of 84% on the control day to 100% after two days glucose infusion). Plasma insulin and C-peptide responses to a 10.0 mmol/l hyperglycaemic clamp increased over the two days of the study (insulin from median 48 mU/l to 73 mU/l and C-peptide from median 2.0 pmol/ml to 2.6 pmol/ml). Glucose tolerance to the additional glucose infusion stimulus improved, suggesting that the increased insulin response during hyperglycaemia was enhancing peripheral glucose uptake. The calculated peripheral insulin sensitivity was unchanged during the hyperglycaemic clamp. Thus, in response to the two days of basal hyperglycaemia, both the basal and stimulated Beta-cell responses were enhanced and there was no evidence for ‘glucose toxicity’ to the Beta-cells.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00400275
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  • 5
    Electronic Resource
    Electronic Resource
    Receptor-recycling model of clearance and distribution of insulin in the perfused mouse liver (1991)
    Springer
    Diabetologia 34 (1991), S. 613-621 
    Details
    ISSN: 1432-0428
    Keywords: Insulin ; hepatic clearance ; receptor recycling ; receptor-mediated endocytosis ; physiological model ; mouse liver perfusion
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary After perfusion of mouse livers with A14-125I-insulin for designated intervals, an acid-wash technique was employed to separately measure the surface-bound (Xs) and intracellular (Xi) A14-125I-insulin, as well as intracellular degradation products (Xdeg) of labelled insulin. From the perfusate concentrations (Cp) of A14-125I-insulin, the apparent intrinsic hepatic clearance of labelled insulin at a high dose (0.2 nmol/l) was shown to be 60% smaller than that at a low dose (0.018 nmol/l), indicating that the cellular uptake of insulin is remarkably nonlinear at the concentration range examined. From the time courses of Cp, Xs, Xi and Xdeg, the hepatic insulin disposition was shown to be largely accounted for by the receptor-mediated endocytosis. The observed data at the low dose were analysed to estimate biochemical parameters, (i.e., total receptor number, endocytotic rate constant and intracellular degradation rate constant) according to “receptor-recycling” and “non-receptor-recycling” models, using a computer-aided optimization procedure. The “receptor-recycling” model could not only adequately explain the Cp, Xs, Xi and Xdeg at the low dose, but also predict the Cp at the high dose. On the other hand, a “non-receptor-recycling” model, in which recycling of receptors was not assumed, could also explain the observed data at the low dose, but failed to predict the Cp at the high dose, indicating that the receptor recycling process is necessary to explain the hepatic insulin clearance at high insulin concentrations, at which hepatic insulin clearance should be limited by the rate of receptor recycling. However, the applicability of our model might be limited within the physiologic insulin concentrations, because of the negative co-operativity of insulin-receptor interaction and a high-capacity, non-degradative and more rapidly recycling pathway for receptors that may occur at high concentrations of insulin. In conclusion, we have developed a mathematical model of hepatic insulin clearance and distribution under physiological conditions, including receptor binding, receptor-mediated endocytosis and receptor recycling, which has been so far demonstrated using isolated hepatocytes.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00400989
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  • 6
    Electronic Resource
    Electronic Resource
    Time-related, cross-sectional and prospective follow-up of pancreatic endocrine function after pancreas allograft transplantation in Type 1 (insulin-dependent) diabetic patients (1991)
    Springer
    Diabetologia 34 (1991), S. S57 
    Details
    ISSN: 1432-0428
    Keywords: Insulin ; C-peptide ; Glucagon ; Pancreas ; Transplantation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary It has been established that successful pancreas transplantation in Type 1 (insulin-dependent) diabetic patients results in normal but exaggerated phasic glucose-induced insulin secretion, normal intravenous glucose disappearance rates, improved glucose recovery from insulin-induced hypoglycaemia, improved glucagon secretion during insulin-induced hypoglycaemia, but no alterations in pancreatic polypeptide responses to hypoglycaemia. However, previous reports have not segregated the data in terms of the length of time following successful transplantation and very little prospective data collected over time in individual patients has been published. This article reports that in general there are no significant differences in the level of improvement when comparing responses as early as three months post-operatively up to as long as two years post-operatively when examining the data cross-sectionally in patients who have successfully maintained their allografts. Moreover, this remarkable constancy in pancreatic islet function is also seen in a smaller group of patients who have been examined prospectively at various intervals post-operatively. It is concluded that successful pancreas transplantation results in remarkable improvements in Alpha and Beta cell but not PP cell function that are maintained for at least one to two years.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00587621
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  • 7
    Electronic Resource
    Electronic Resource
    In vivo metabolic action of insulin-like growth factor I in adult rats (1991)
    Springer
    Diabetologia 34 (1991), S. 144-149 
    Details
    ISSN: 1432-0428
    Keywords: Insulin ; insulin-like growth factor I ; euglycaemic clamping ; glucose metabolism ; lipogenesis ; glycogenesis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The acute metabolic actions of insulin-like growth factor I were studied in anaesthetized adult rats and its potency was compared to that of insulin. Following an i. v. bolus injection of insulin-like growth factor I a dose-dependent decrease of blood glucose and serum non-esterified fatty acid concentrations was noted with a potency of about 2% that of insulin. Stimulation of total body glucose disposal during euglycaemic clamping required ∼ 50times higher insulin-like growth factor I serum concentrations to achieve an identical half-maximal response. A similar difference in potency was observed for the stimulatory action on 2-de-oxyglucose uptake and on glycogen formation in skeletal muscle. Lipogenesis in epididymal fat pads was increased dose-dependently by both hormones requiring approximately 30 times higher half-maximally effective serum concentrations of insulin-like growth factor I. These data demonstrate that insulin-like growth factor I exerted acute insulin-like metabolic actions in vivo with low potency. These effects were probably mediated via insulin receptors. A preferential stimulation of glucose metabolism in skeletal muscle was not observed.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00418267
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  • 8
    Electronic Resource
    Electronic Resource
    Ontogenesis of insulin processing in fetal rat hepatocytes (1991)
    Springer
    Diabetologia 34 (1991), S. 868-876 
    Details
    ISSN: 1432-0428
    Keywords: Insulin ; fetal rat hepatocytes ; glycogen ; endocytosis ; degradation ; retroendocytosis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary We studied insulin processing and hepatic glycogenesis in cultured hepatocytes isolated from rat fetuses of 17, 19, and 21 days of gestation. Steady-state insulin binding increased by 250% between days 17 and 19, from 145±8 to 361±52 fmol/mg protein, and by an additional 40% (405±69 fmol/mg protein) by 21 days of gestation. At 37°C, 125I-insulin was rapidly (t1/2〈5 min) internalized by hepatocytes at all three ages, reaching maximal levels (63–76% of the total cell-associated radioactivity) by 15 min. 125I-labelled degradation products appeared rapidly (t1/2〈15 min) within the cells. Yet, the majority (68–77%) of the intracellular radioactivity consisted of intact 125I-insulin, even after 4 h at 37°C. Hepatocytes pre-loaded with 125I-insulin and then acid-stripped of surface-bound radioactivity, rapidly released both intact 125I-insulin (retroendocytosis) and its radiolabelled degradation products. While intact insulin was initially released more rapidly (t1/2〈6 min), and reached a plateau after 15–30 min, the degradation products continued to accumulate in the medium for at least 4 h. Methylamine inhibited intracellular 125I-insulin degradation at all three gestational ages and also blocked insulin-stimulated glycogenesis in 19- and 21-day hepatocytes, without altering basal glycogen synthesis. Insulin-stimulated glycogenesis was not induced in 17-day fetal rat hepatocytes in control or methylamine-treated cultures. We conclude that both degradative and retroendocytotic pathways for processing insulin are present in fetal rat hepatocytes by 17 days of gestation. Further, insulin-receptor processing was functionally related to the glycogenic action of insulin in responsive 19- and 21-day fetal rat hepatocytes
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00400194
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  • 9
    Electronic Resource
    Electronic Resource
    Binding and biological effects of insulin, insulin analogues and insulin-like growth factors in rat aortic smooth muscle cells. Comparison of maximal growth promoting activities (1991)
    Springer
    Diabetologia 34 (1991), S. 307-313 
    Details
    ISSN: 1432-0428
    Keywords: Insulin ; insulin analogues ; insulin-like growth factors ; proliferation ; vascular smooth muscle cells
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Binding and growth promoting effects of insulin, insulin analogues modified in the B chain, proinsulin, insulin-like growth factor-I and -II were studied in cultured rat aortic smooth muscle cells. Specific binding of125I-insulin was 0.9±0.2% of total 125I-insulin added, and the IC50-value was estimated to 8.9 pmol/1. The insulin analogue B10 Asp tended to be more potent than insulin in displacing 125I-insulin, B28 Asp was equipotent, B9 Asp/B27 Glu was approximately 100 times less potent and insulin-like growth factor-I more than 1000 times less potent than insulin. Specific binding of 125I-insulin-like growth factor-I after 4 h incubation at 10 °C was five times higher than the specific binding of insulin (4.4±0.4% of total 125I-insulin-like growth factor-I added), and the IC50-value was 0.3 nmol/l. Insulin was approximately 500 times less potent than insulin-like growth factor-I in displacing 125I-insulin-like growth factor-I. The insulin analogue B10 Asp was slightly more potent and analogue B28 Asp was equipotent with insulin. Analogue B9 Asp/B27 Glu was ten times less potent and proinsulin was more than ten times less potent than insulin. The order of potency was similar for 3H-thymidine incorporation into DNA: insulin-like growth factor-I 〉 B10 Asp 〉 insulin-like growth factor-II 〉 insulin 〉 B28 Asp 〉 B9 Asp/B27 Glu 〉 proinsulin. The maximal effect of insulin-like growth factor-I on 3H-thymidine incorporation was 71±16% higher than the maximal effect of insulin. The maximal effect of insulin-like growth factor-II was at least as high as the effect of insulin-like growth factor-I. Furthermore, the maximal effect of B10 Asp was 62±10% higher than the maximal effect of insulin. Insulin-like growth factor-I and B10 Asp tended to increase cell number more than insulin. In conclusion, this study shows that insulin analogues interact with different potencies with receptors for insulin and insulin-like growth factor-I in vascular smooth muscle cells and that insulin-like growth factors and the insulin analogue B10 Asp have more pronounced growth effects than insulin. Substitution of the amino acid Asp for His at position B10 in insulin makes the molecule more similar to insulin-like growth factor-I, chemically and probably also biologically.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00405001
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  • 10
    Electronic Resource
    Electronic Resource
    Reduced secretion of gastric inhibitory polypeptide in turner patients with impaired glucose tolerance (1991)
    Springer
    European journal of pediatrics 150 (1991), S. 339-342 
    Details
    ISSN: 1432-1076
    Keywords: Glucose tolerance ; Turner syndrome ; Insulin ; GIP
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract There is a well documented increase in the incidence of abnormal glucose tolerance in patients with Turner syndrome. To elucidate the pathophysiology of this phenomenon, we studied the serum concentrations of gastric inhibitory polypeptide (GIP) — as probably the most important hormonal factor of the entero-insular axis — in relation to impaired glucose tolerance in this syndrome. Oral glucose tolerance tests were performed in 12 Turner patients with simultaneous determination of plasma glucose, insulin and GIP. An impaired glucose tolerance (iGT) was found in four patients with a chronological age between 12.3 and 14.9 years. These patients were compared with found Turner patients of similar age and weight and a normal glucose tolerance (nGT). The highest insulin level occurred 90 min after stimulation in the patients with iGT compared to 30 min in the nGT group. Interestingly, the total areas under the insulin curves were not different. Stimulated plasma GIP concentrations and the areas under the GIP curves wer significantly lower in iGT compared to nGT patients. A disturbed entero-insular axis might contribute to the delayed — rather than diminished — release of insulin in patients with Turner syndrome and impaired glucose tolerance.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01955936
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  • 11
    Electronic Resource
    Electronic Resource
    Extrapancreatic insulin effect of glibenclamide (1991)
    Springer
    European journal of clinical pharmacology 40 (1991), S. 379-381 
    Details
    ISSN: 1432-1041
    Keywords: Insulin ; glibenclamide ; C-peptide ; insulin catabolism ; diabetes
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Medicine
    Notes: Summary In eight patients with uncomplicated non insulin dependent diabetes mellitus, serum insulin levels, serum C-peptide levels and blood glucose levels were measured before and after oral administration of glibenclamide 0.1 mg/kg body weight and a test meal, or after a test meal alone. The rise in serum insulin levels persisted longer after glibenclamide. The initial rise in serum insulin was of the same magnitude in both situations, as was the rise in serum C-peptide levels during the entire 5 h study. It is concluded that glibenclamide is able to maintain a more protonged increase in serum insulin levels by inhibiting the degradation of insulin in the vascular endothelial cells of the liver. The inhibition contributes to the blood glucose lowering effect of glibenclamide.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00265847
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  • 12
    Electronic Resource
    Electronic Resource
    Risks of jet injection of insulin in children (1991)
    Springer
    European journal of pediatrics 150 (1991), S. 554-556 
    Details
    ISSN: 1432-1076
    Keywords: Diabetes ; Insulin ; Therapy ; Child
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract The aim of our study was to assess whether a non-invasive insulin injector could improve the metabolic control of ten diabetic children complaining of painful injections with syringe and needle. The cumulative study period amounted to 1347 days. Whereas a non-significant rise in insulin needs was observed (from 0.98±0.03 to 1.03±0.06 units/kg per day, mean ± sem), mean HbA1c value remained unchanged (8.9%±0.4% vs 9.0%±0.5%). Jet injections were felt as less painful than those using syringe and needle (nine out of ten cases). This advantage was hampered by side-effects in eight out of ten cases such as episodes of glycoketonuria (six out of ten cases) leading to hospitalization in three patients. Other side-effects included inability to adjust injection pressure (four out of ten cases) and technical failure requiring an exchange of injector in five cases. The four children with most serious problems were significantly younger (P=0.009) than other subjects. In conclusion, this type of injector should be discouraged in young diabetic children. For older children and adolescents, it may be an alternative to syringe and needle provided repeated detailed information and tight medical supervision is available.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02072205
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  • 13
    Electronic Resource
    Electronic Resource
    Effects of insulin and somatostatin on the growth and the colony formation of two human pancreatic cancer cell lines (1991)
    Springer
    Journal of cancer research and clinical oncology 117 (1991), S. 416-420 
    Details
    ISSN: 1432-1335
    Keywords: Pancreas cancer ; Insulin ; Somatostatin ; Growth ; Colony formation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The effects of insulin and somatostatin on the growth and the colony formation of two human pancreatic cancer cell lines, BxPC-3 and SOJ-6, were studied. The BxPC-3 cell line (American Type Culture Collection no. CRL 1687) was derived from a moderately differentiated pancreatic adenocarcinoma. The SOJ-6 cell line is a subclone of SOJ that was initiated from ascites of a well-differentiated pancreatic adenocarcinoma. Both cell lines express fetoacinar pancreatic antigen, an antigen that might be associated with early transformation stages. However, these lines have different proliferation and tumoral powers. SOJ-6 cells showed an almost twofold higher division rate over BxPC-3 cells when cultured in RPMI-1640 medium containing 10% fetal bovine serum. The tumorigenic degree of SOJ-6 cells, as assessed by tumor growth in nude mice, was about three times greater than that of BxPC-3. The in vitro growth of BxPC-3 cells was significantly promoted by insulin, and was slightly inhibited by somatostatin, whereas the growth of SOJ-6 cells was not influenced by these hormones. Using a clonogenic assay in soft agar, the average ratio of colony numbers formed by SOJ-6 and BxPC-3 was about 10/1, indicating a good correlation between the colony formation and tumorigenic degree in vivo. In this test, the number of colonies formed by BxPC-3 cells was increased about twofold in insulin-supplemented medium. On the other hand, somatostatin inhibited the colony formation by a factor of four to six. However, no hormonal modulation of the colony formation of SOJ-6 cells was observed. Our data show that pancreatic cancer cell lines respond differently to pancreatic hormones, and suggest that this may be correlated to a tumour stage or a tumour type.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01612760
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  • 14
    Electronic Resource
    Electronic Resource
    Linear prediction enhancement of 2D heteronuclear correlated spectra of proteins (1991)
    Springer
    Journal of biomolecular NMR 1 (1991), S. 237-246 
    Details
    ISSN: 1573-5001
    Keywords: Linear prediction ; Heteronuclear correlation ; 2D NMR spectra ; Protein ; Insulin
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Summary Linear prediction has been used to extrapolate the t1 domain of natural abundance1H−13C correlated two-dimensional (2D) FIDs of insulin. The FIDs were obtained by two different heteronuclear correlation experiments, one that utilizes heteronuclear multiple-quantum coherence during t1, and one that utilizes13C single-quantum coherence. It is shown that the enhancement of the resolution and sensitivity in the F1 dimension of the Fourier transform spectrum that results from the linear prediction extrapolation allows the t1 domain to be confined to a relatively short time period where the signal intensity is at maximum. In particular, it is found that the enhancement thus obtained is sufficiently good to allow an observation of the difference between the F1 line widths in the single-quantum and double-quantum coherence spectra.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01875517
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  • 15
    Electronic Resource
    Electronic Resource
    Effect of sulphonylurea on glucose-stimulated insulin secretion in healthy and non-insulin dependent diabetic subjects: a dose-response study (1991)
    Springer
    Acta diabetologica 28 (1991), S. 162-168 
    Details
    ISSN: 1432-5233
    Keywords: Insulin ; C-peptide ; Glucose ; Glipizide ; Non-insulin-dependent diabetes mellitus
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract The effect of a rapid-acting sulphonylurea, glipizide, on the dose-response relationship between the β-cell response (insulin and C-peptide secretion) and the ambient plasma glucose concentration was examined in 12 healthy and 6 non-insulin-dependent diabetic subjects. The subjects participated in two sets of experiments which were performed in random order: (A) four hyperglycaemic clamp studies, during which the plasma glucose concentration was raised for 120 min by 1 (only in healthy subjects), 3, 7, and 17 mmol/l; and (B) the same four hyperglycaemic clamp studies preceded by ingestion of 5 mg glipizide. All subjects participated in a further study, in which glipizide was ingested and the plasma glucose concentration was maintained at the basal level. In control subjects in the absence of glipizide, the firstphase plasma insulin response (0–10 min) increased progressively with increasing plasma glucose concentration up to 10 mmol/l, above which it tended to plateau. Glipizide augmented the first-phase insulin response without changing the slope of the regression line relating plasma insulin to glucose concentrations. The second-phase plasma insulin response (20–120 min) increased linearly with increasing hyperglycaemia (r=0.997). Glipizide alone increased the plasma insulin response by 180 pmol/l. A similar increase in plasma insulin response following glipizide was observed at each hyperglycaemic step, indicating that glipizide did not affect the sensitivity of the β-cell to glucose. First-phase insulin secretion was reduced in the type 2 (non-insulin-dependent) diabetic patients, and was not influenced by glipizide. The dose-response curve relating second-phase insulin secretion to the ambient plasma glucose concentration was significantly (P〈0.001) flatter in the diabetic patients than in the control subjects. Glipizide alone increased the plasma insulin response by 60 pmol/l without changing the slope of the dose-response curve. It is concluded that, in both type 2 diabetic patients and healthy subjects: (A) sulphonylurea augments glucose-stimulated second-phase insulin secretion without changing the sensitivity of the β-cell to glucose; (B) first-phase insulin secretion is reduced in non-insulin-dependent diabetic patients with fasting hyperglycaemia and is not influenced by sulphonylurea.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00579720
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  • 16
    Electronic Resource
    Electronic Resource
    Immunohistochemical colocalization of insulin, aromatic L-amino acid decarboxylase and dopamine beta-hydroxylase in islet B cells of chicken pancreas (1991)
    Springer
    Cell & tissue research 263 (1991), S. 131-136 
    Details
    ISSN: 1432-0878
    Keywords: B cells ; Insulin ; Catecholamine ; synthesizing enzymes ; Immunohistochemistry ; Chicken
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The identity of the monoamine which produces a very weak formaldehyde-induced fluorescence in some pancreatic islet cells was studied by fluorescence microscopy and immunohistochemistry either on the same tissue section or on serial tissue sections of tissue from male chickens. Pancreatic islet cells showing this very weak formaldehyde-induced fluorescence react immunohistochemically with antisera directed against insulin, aromatic L-amino acid decarboxylase and dopamine beta-hydroxylase and therefore appear to be islet B cells producing insulin and noradrenaline.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00318408
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  • 17
    Electronic Resource
    Electronic Resource
    The endocrine pancreas of glucagon-and somatostatin-immunized rabbits (1991)
    Springer
    Cell & tissue research 265 (1991), S. 261-273 
    Details
    ISSN: 1432-0878
    Keywords: Endocrine pancreas ; Immunization ; Insulin ; Glucagon ; Somatostatin ; Electron microscopy ; Rabbit (Chinchilla, Ch: b Ch)
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary An active or passive immunization against hormones and the subsequent neutralization of hormones by circulating antibodies is a valuable tool for the identification of hormonal action. To recognize presumed local (autocrine, paracrine) effects exerted by pancreatic hormones, the endocrine pancreas of rabbits was investigated electron-microscopically after long-term immunization against glucagon or somatostatin. Glucagon immunization resulted in hyperplasia and hypertrophy of glucagon- (A-) cells and in their increased metabolic activities: They showed prominent nucleoli, increased amounts of endoplasmic reticulum, Golgi areas, and mitochondria. These changes were paralleled by alterations in secretion granules (increased size, decreased hormonal content), increased numbers of lysosomes (crinophagic bodies), and an increment of the filamentous system. Basically, these findings point to an autocrine regulation of A-cells. Following somatostatin immunization, somatostatin- (D-) cells were hyperplastic but unchanged in their metabolic state. Instead, insulin-(B-) cells and A-cells exhibited equivalents of increased cellular activities (parameters, see above). This stimulation most probably is caused by cancelled paracrine (inhibitory) effects of somatostatin. The changes observed after both immunizations were differently expressed in morphologically heterogeneous islet types (size, angioarchitecture, cellular composition, microtopology of the various cell types). It is concluded, therefore, that the regulation of islets is not uniform. Autocrine and paracrine effects exerted by islet hormones are of different significance in individual islets, or they interfere differently with other regulatory signals.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00398074
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  • 18
    Electronic Resource
    Electronic Resource
    Effects of carbohydrate type on postprandial blood pressure, neuroendocrine and gastrointestinal hormone changes in the elderly (1991)
    Springer
    Clinical autonomic research 1 (1991), S. 219-224 
    Details
    ISSN: 1619-1560
    Keywords: Postprandial hypotension ; Elderly ; Carbohydrate ; Neurotensin ; Catecholamines ; Insulin
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Previous studies have demonstrated that blood pressure falls postprandially in fit elderly subjects, the greatest changes occurring after meals with a high carbohydrate content. To evaluate the influence of the type of carbohydrate on postprandial blood pressure, the effects of equivalent energy content (2.4 MJ) high complex (starch) and high simple (monosaccharide) carbohydrate meals were studied in seven healthy elderly subjects. Blood pressure, heart rate, autonomic function, plasma catecholamines, insulin and neurotensin levels were measured pre- and postprandially. Greater falls in supine and erect systolic blood pressure occurred after the high simple than the high complex carbohydrate meal (p 〈 0.05). No differences were found in supine or erect diastolic blood pressure, heart rate or in any of the biochemical parameters measured between the meal types. It is concluded that a simple carbohydrate meal results in a greater postprandial fall in blood pressure than an equivalent energy complex carbohydrate meal in the elderly, although the mechanisms for these changes are unknown.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01824990
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  • 19
    Electronic Resource
    Electronic Resource
    Glucoregulatory hormones in man at high altitude (1991)
    Springer
    European journal of applied physiology 62 (1991), S. 286-291 
    Details
    ISSN: 1439-6327
    Keywords: High altitude ; Cortisol ; Insulin ; Growth hormone
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Concentrations of glucose, lactic acid, free fatty acid (FFA), insulin, cortisol and growth hormone (GH) in the blood were monitored in 15 euglycaemic men (sojourners, SJ) at sea level (SL) and while at altitudes of 3500 m and 5080 m, in acclimatised low landers (ALL) and in high altitude natives (HAN). In SJ, blood glucose and insulin concentrations showed a significant increase on the 3rd and 7th day after arrival at high altitude (HA), thereafter returning to sea level values and remaining the same during the entire period of their stay at 3500 m. Subsequently, on arrival at higher altitude (5080 m) the glucose concentrations again showed an increase over the preceding values and returned to SL values on day 41 while at 5080 m. A significant increase in cortisol concentrations was seen on day 3 after arrival at HA and the increased levels were maintained until day 21 at 3500 m. The cortisol concentrations on day 30 after arrival at 5080 m came down to SL values and remained unchanged thereafter. No appreciable change in GH and FFA was seen during the sojourn at HA. On the other hand, blood lactic acid concentration decreased significantly. There was no difference between the fasting glucose concentrations in ALL at 3500 m and in HAN at 3500 m and 4200 m compared to values of SJ at SL, whereas ALL at 4200 m had higher glucose values. Concentrations of plasma insulin and GH in ALL and HAN were higher than the values of SJ at SL, whereas cortisol values did not show any difference. These observations indicated that at HA the glucose values were high for the insulin concentration observed and might have been due to increased secretion of GH by the pituitary gland.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00571554
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  • 20
    Electronic Resource
    Electronic Resource
    Training effects of cross-country skiing and running on maximal aerobic cycle performance and on blood lipids (1991)
    Springer
    European journal of applied physiology 62 (1991), S. 400-404 
    Details
    ISSN: 1439-6327
    Keywords: Endurance conditioning ; Aerobic fitness ; Lipoproteins ; Insulin
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Two experiments were carried out to compare the cardiorespiratory and metabolic effects of cross-country skiing and running training during two successive winters. Forty-year-old men were randomly assigned into skiing (n = 15 in study 1,n = 16 in study 2), running (n = 16 in study 1 andn = 16 in study 2) and control (n = 17 in study 1 andn = 16 in study 2) groups. Three subjects dropped out of the programme. The training lasted 9–10 weeks with 40-min exercise sessions three times each week. The training intensity was controlled at 75%–85% of the maximal oxygen consumption (VO2max) using portable heart rate metres and the mean heart rate was 156–157 beats·min−1 in the training groups. In the pooled data of the two studies the mean increase in theVO2max (in ml·min−1·kg−1) on a cycle ergometer was 17% for the skiing group, 13% for the running group and 2% for the control group. The increase inVO2max was highly significant in the combined exercise group compared to the control group but did not differ significantly between the skiing and running groups. The fasting serum concentrations of lipoproteins and insulin did not change significantly in any of the groups. These results suggested that training by cross-country skiing and running of the same duration and intensity at each session for 9–10 weeks improved equally the cardiorespiratory fitness of untrained middle-aged men.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00626610
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  • 21
    Electronic Resource
    Electronic Resource
    Effects of supramaximal exercise on blood glucose levels during a subsequent exercise (1991)
    Springer
    European journal of applied physiology 63 (1991), S. 48-51 
    Details
    ISSN: 1439-6327
    Keywords: Insulin ; Hyperglycemia ; Hyperinsulinemia ; Human subjects
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The purpose of the present investigation was to examine the effects of hyperglycoemia induced by supramaximal exercise on blood glucose homeostasis during submaximal exercise following immediately after. Six men were subjected to three experimental situations; in two of these situations, 3 min of high-intensity exercise (corresponding to 112, SD 1%VO2 max) was immediately followed by either a 60-min period of submaximal exercise (68, SD 2%VO2 max) or a 60-min resting period. In the third situation, subjects performed a 63-min period of submaximal exercise only. There were no significant differences between the heurt rates, oxygen uptakes, and respiratory exchange ratios during the two submaximal exercise bouts (〉 15 min) whether or not preceded by supramaximal exercise. The supramaximal exercise was associated within 10 min of the start increases (P〈0.05) in blood glucose, insulin, and lactate concentrations. This hyperglycemia was more pronounced when subjects continued to exercise submaximally than when they rested (at 7.5 min;P〈0.05). There was a more rapid return to normal exercise blood glucose and insulin values during submaximal exercise compared with rest. The data show that the hyperinsulinemia following supramaximal exercise is corrected in between 10–30 min during submaximal exercise following immediately, suggesting that this exercise combination does not lead to premature hypoglycemia.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00760800
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  • 22
    Electronic Resource
    Electronic Resource
    Thermogenic effect of adrenaline: interaction with insulin (1991)
    Springer
    European journal of applied physiology 63 (1991), S. 417-423 
    Details
    ISSN: 1439-6327
    Keywords: Energy expenditure ; Thermogenesis ; Epinephrine ; Insulin
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The contribution of insulin (3.6 pmol sd kg body mass−1·min−1 to adrenaline-induced (0.164 nmol · kg fat free mass−1·min−1) thermogenesis was studied in ten postabsorptive healthy volunteers using two sequential protocols. Variables considered were oxygen consumption as well as carbon dioxide production, heart rate, blood pressure, plasma concentrations of glucose, insulin, glycerol, free fatty acids,β-HO-butyrate and lactate. Adrenaline increased plasma concentrations of glucose, glycerol, free fatty acids, andβ-HO-butyrate, and heart rate and metabolic rate during normo-insulinaemia [61.3 (SEM 6.6) pmol·−1]. Similar effects were observed during hyperinsulinaemia [167.9 (SEM 18.7) pmol·−1], but the effect of adrenaline on oxygen consumption was reduced. On average, metabolic rate increased by 12.9% during normo-insulinaemia and by 8.9% during hyperinsulinaemia. We concluded that relative hyperinsulinaemia resulted in decreased adrenaline-induced thermogenesis and therefore increased whole body anabolism.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00868072
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  • 23
    Electronic Resource
    Electronic Resource
    Effects of muscarinic blockade on the thermic effect of oral or intravenous carbohydrate (1991)
    Springer
    European journal of applied physiology 63 (1991), S. 242-249 
    Details
    ISSN: 1439-6327
    Keywords: Atropine ; Glucose ; Fructose ; Dietary thermogenesis ; Insulin
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Muscarinic blockade by atropine has been shown to decrease the thermic effect of a mixed meal, but not of intravenous glucose. To further delineate the mechanisms involved in the atropine-induced inhibition of thermogenesis after a meal, plasma substrate and hormone concentrations, energy expenditure (EE) and substrate oxidation rates were measured before and during a continuous glucose infusion (44.4 μmol·kg−1·min−1) with or without atropine. After 2 h of glucose infusion, a 20-g oral fructose load was administered while the glucose infusion was continued. Plasma insulin concentrations attained a plateau at 596 (SEM 100) pmol·l−1 after 120 min of glucose infusion and were not affected by muscarinic blockade; plasma glucose concentrations peaked at 13.3 (SEM 0.5) mmol·l−1 at 90 min and decreased progressively thereafter; no difference was observed with or without atropine. Plasma free fatty acid and glucagon concentrations, with or without atropine, were both decreased to 201 (SEM 18) μmol·l−1 and 74 (SEM 4) ng·l−1, respectively, after 2 h of glucose infusion, and were not further suppressed after oral fructose. Carbohydrate oxidation rates (CHOox) increased to 20.8 (SEM 1.4) μmol·kg−1·min−1 and lipid oxidation rates (Lox) decreased to 1.5 (SEM 0.3) μmol·kg−1·min−1 between 90 and 120 min after the beginning of glucose infusion and were not affected by atropine. Glucose-induced thermogenesis was similar with [6.5% (SEM 1.4%) of basal EE] or without [6.0% (SEM 1.0%), NS) muscarinic blockade during the 30 min preceding fructose ingestion. During the second half-hour after fructose ingestion, atropine infusion inhibited markedly the stimulation of CHOox [+2.8 (SEM 1.0) μmol·kg−1·min−1 vs +6.9 (SEM 1.0) μmol·kg−1·min−1, saline, P〈0.02] and the suppression of Lox [−0.8 (SEM 0.2) μmol·kg−1·min−1 vs −1.4 (SEM 0.2) μmol·kg−1·min−1, saline, P〈0.05]. Carbohydrate-induced thermogenesis during the second half-hour after fructose ingestion, increased to 13.0% (SEM 2.0%) without atropine and was suppressed to 7.7% (SEM 1.9%) (P〈 0.05, vs saline) with atropine. It was concluded that muscarinic blockade suppressed the increase of thermogenesis observed after oral fructose, but not during intravenous glucose infusion and that this suppression occurred independently of alterations of plasma insulin concentrations.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00233855
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  • 24
    Electronic Resource
    Electronic Resource
    Effects of sudden pressure changes in the surrounding gas phase on flow properties of bulk solidsPaper presented at the “Jahrestreffen der Verfahrens-Ingenieure”, Berlin, September 27 to 29, 1989. (1991)
    Weinheim : Wiley-Blackwell
    Chemical Engineering & Technology - CET 14 (1991), S. 53-59 
    Details
    ISSN: 0930-7516
    Keywords: Chemistry ; Industrial Chemistry and Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: The variation in the behaviour of bulk solids as a result of sudden pressure changes in the surrounding gas phase is of interest in the application of lock hoppers for transfer of bulk solids into pressure vessels. By using such sluice systems, problems occur due to consolidation of the pressurized bulk solids. This paper presents the results of experimental and theoretical research, which allow to describe the influence of several parameters on pressure compensation and the degree of consolidation. With reference to the forces and mechanisms responsible for consolidation, it is possible to describe the different consolidation behaviour of incompressible (limestone) and compressible (hard coal) bulk solids.
    Additional Material: 12 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/ceat.270140108
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  • 25
    Electronic Resource
    Electronic Resource
    Flow characteristics of large oscillating drops in liquid-liquid systems (1991)
    Weinheim : Wiley-Blackwell
    Chemical Engineering & Technology - CET 14 (1991), S. 65-72 
    Details
    ISSN: 0930-7516
    Keywords: Chemistry ; Industrial Chemistry and Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: A study was made of the flow characteristics of large oscillating drops of pure liquid-liquid systems, using a thermostatically-controlled, rising drop column, 50 mm in diameter and 1000 mm in length. Mirrors in the jacket enabled front and side views of drops to be photographed simultaneously. Single drops in the size range 5-10 mm were investigated with both mutually-saturated phases and when the solute was being transferred from the dispersed phase. The systems studied were (1) toluene and acetone (dispersed)-water (continuous), and (2) n-heptane and acetone (dispersed)-water (continuous). Acetone concentrations were varied up to 3.75 kmol/m3. The oscillations of a travelling drop were asymmetrical; therefore, the amplitude cannot be expressed accurately in terms of only two axes. The area change of the drop compared to that of a sphere of equal volume ‘ε’, was shown to represent the amplitude accurately. The periods of droplet oscillation were uniform for the mutually saturated systems of constant physical and flow properties but changed when mass transfer was taking place. The interfacial tension exerted a marked effect on the amplitude, which also depended upon the oscillation frequency. The amplitude changed with droplet size in a similar manner to the terminal velocity, i.e. it increased with increasing size until it reached a maximum, subsequently decreasing less rapidly. The drag coefficient increased with increasing rate of mass transfer from the drop. Correlation of the results and the area eccentricity ‘ε’ by dimensional analysis embracing all possible parameters and physical properties affecting drop oscillation, resulted in the correlation ε = 0.22 Sr0.42 We-0.53 M0.13 with a mean deviation of ± 14%. This will facilitate more accurate prediction of the interfacial area for mass transfer calculations, relating to equipment containing droplets in the oscillating regime.
    Additional Material: 7 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/ceat.270140110
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  • 26
    Electronic Resource
    Electronic Resource
    Development of rate expressions for the catalytic decomposition of nitric oxide with ammonia on iron oxide (1991)
    Weinheim : Wiley-Blackwell
    Chemical Engineering & Technology - CET 14 (1991), S. 113-117 
    Details
    ISSN: 0930-7516
    Keywords: Chemistry ; Industrial Chemistry and Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: The reduction of nitric oxide with ammonia on iron oxide catalysts has been studied in a continuous-flow recycle reactor using simulated flue gas in the temperature range from 573 to 673 K. NO and HN3 concentrations were varied between 0 and 1000 vpm, O2 and H2O concentrations between 0 and 9 vol.-%, the remainder being nitrogen. In the presence of oxygen, the formulated reaction rate equation describes the measured rates of the main reaction NO + 2/3 NH3 ⇄ 5/6 N2 + H2O. Its form corresponds to the Langmuir-Hinshelwood type. The rate equation well fits the data, which cover the whole industrial temperature and concentration range. In the absence of oxygen, the measured reaction rates can be best described by a power law.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/ceat.270140208
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  • 27
    Electronic Resource
    Electronic Resource
    Vibration induced pneumatic coveyingPaper presented at the Fourth International Conference on Pneumatic Coveying Technology, Glasgow, 26 to 28 June 1990.Dedicated to Professor Dr.-Ing. Alfons Mersmann on the occasion of his 60th birthday (1991)
    Weinheim : Wiley-Blackwell
    Chemical Engineering & Technology - CET 14 (1991), S. 141-145 
    Details
    ISSN: 0930-7516
    Keywords: Chemistry ; Industrial Chemistry and Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: A new transport system has been developed which combines vibration of the conveying pipe with amplitudes of the order of fractions of a millimetre with rather low superficial velocities of the carrier gas. This new system was specially designed for gentle transport of fragile particulate materials.
    Additional Material: 8 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/ceat.270140213
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  • 28
    Electronic Resource
    Electronic Resource
    Safe operation of a batch reactor: Safe storage of organic peroxides in supply vesselsDedicated to Professor Dr. Kurt Dialer on the occasion of his 70th birthday (1991)
    Weinheim : Wiley-Blackwell
    Chemical Engineering & Technology - CET 14 (1991), S. 147-161 
    Details
    ISSN: 0930-7516
    Keywords: Chemistry ; Industrial Chemistry and Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: In this study, we investigated the limits of safe operation for a cooled reactor, operated batchwise. As an example of a single-phase reaction, we studied the decomposition of t-butyl peroxypivalate, a well-known organic peroxide, undergoing self-heating at relatively low temperatures. If sufficiently diluted, it can be supplied to a polymerization process from large, cooled but unstirred vessels. We present a number of extensions to the existing homogeneous explosion theory, namely a practical definition of the critical condition, its calculation, and expressions for the available time before runaway in the case of a supercritical condition, taking into account the effects of natural convection inside the vessel and the reactant conversion. The extensions of the theory were confirmed by adiabatic and non-adiabatic runaway experiments on bench scale, and natural convection cooling experiments with liquids in various packages.
    Additional Material: 13 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/ceat.270140302
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  • 29
    Electronic Resource
    Electronic Resource
    Three-component mass transfer in liquid-liquid extraction with the system glycerol-acetone-water. Part 1: The influence of vanishing diffusion coefficients in binodal states on the mechanisms of mass transferDedicated to Professor Dr.-Ing. Alfons Mersmann on the occasion of his 60th birthday (1991)
    Weinheim : Wiley-Blackwell
    Chemical Engineering & Technology - CET 14 (1991), S. 186-191 
    Details
    ISSN: 0930-7516
    Keywords: Chemistry ; Industrial Chemistry and Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: This contribution deals with the consequences of the decrease in diffusion coefficients at the boundaries of miscibility in fluid systems and its effect on the mechanisms of mass transfer. The liquid-liquid (1-1) extraction involving several components is taken as an example for the discussion of this topic. A short review of Hampe's theory on transport mechanisms in the transition regions of interfaces [1] explains the intrinsic interdependence between mass and momentum transfer. Finally, a discussion of the peculiarities of resistances to mass transfer in boundary layers, based on the changes in molecular transport properties, is presented.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/ceat.270140306
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  • 30
    Electronic Resource
    Electronic Resource
    Effect of doping with nickel and copper on catalytic behaviour of wide-pore zeolites with different pore structures (1991)
    Weinheim : Wiley-Blackwell
    Chemical Engineering & Technology - CET 14 (1991), S. 200-208 
    Details
    ISSN: 0930-7516
    Keywords: Chemistry ; Industrial Chemistry and Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: The catalytic properties of wide-pore zeolites, namely Ni- and Cu-doped faujastie H-Y and H-mordenite (H-M) are compared on the example of conversion of n-hexane. After thermal pretreatment of ion-exchanged zeolites, reduction with hydrogen (PH2 ≤ 40 bar) leads to a large number of metallic clusters and crystallites as well as ionic species in the zeolites. Notwithstanding this variety, the different types of catalysts can be divided into three classes: classical bifunctional catalysts (for example NiHM, NiHY) with ion exchange degrees 〉 30%, monofunctional catalysts, such as CuHM and CuHY with high copper contents (ion exchange degree 〉 40%) and metal-doped (Ni and Cu) zeolites which, depending on the conditions of pretreatment, act as bifunctional and/or monofunctional compounds and, therefore, show very unstable reaction behaviour. In addition to the extent of reduction, the cation distribution affects the activity and deactivation behaviour and, to a lesser extent, the product selectivity. The reaction mechanism of bifunctional catalysis is similar to that observed in platinum-doped catalysts, while the mechanism of monofunctional catalysis resembles the process on undoped zeolites.
    Additional Material: 11 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/ceat.270140308
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  • 31
    Electronic Resource
    Electronic Resource
    Decrease of diffusion coefficients near binodal states of liquid-liquid systemsDedicated to Professor Dr.-Ing. Karl Stephan on the occasion of his 60th birthday (1991)
    Weinheim : Wiley-Blackwell
    Chemical Engineering & Technology - CET 14 (1991), S. 219-225 
    Details
    ISSN: 0930-7516
    Keywords: Chemistry ; Industrial Chemistry and Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: This work investigates the thermodynamically based assumption that diffusion at binodal states of unstable fluid systems vanishes. It is shown experimentally that a scaling law, which describes the fall in diffusion near critical points, may also be applied in an extended form to its abatement at the limits of solubility. These results may profoundly affect the modelling of mass transfer between phases whose bulks exhibit states of saturation.
    Additional Material: 9 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/ceat.270140402
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  • 32
    Electronic Resource
    Electronic Resource
    Adaptive pole removal control for a batch polymerization reactor (1991)
    Weinheim : Wiley-Blackwell
    Chemical Engineering & Technology - CET 14 (1991), S. 240-247 
    Details
    ISSN: 0930-7516
    Keywords: Chemistry ; Industrial Chemistry and Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: A systematic method of controller design is introduced to determine the overall charcteristic behaviour developed on process pole removal. The time delay compensation is automatically incorporated in the proposed control law. The implemented tuning parameters in the law are confined to the range between 0 and 1 to guarantee the stability of the overall control system. Subsequently, the fixed and adaptive control strategies are implemented to simulate a batch PVC reaction system. The adaptive control scheme provides good, roubust control of this simulated reactor notwithstanding the wide range of operating conditions and non-linear dynamics of the system. However, the fixed control scheme performs well only for a noise-free system. In addition, two limiting control laws, derived from the proposed method, are also used to simulate the reactor. The results indicate that these laws are not suitable for this non-linear reaction system.
    Additional Material: 13 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/ceat.270140405
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  • 33
    Electronic Resource
    Electronic Resource
    Three-component mass transfer in liquid-liquid extraction with the system glycerol-acetone-water. Part 2: Calculation and experimental investigation of three-component mass transfer in a countercurrent extraction column (1991)
    Weinheim : Wiley-Blackwell
    Chemical Engineering & Technology - CET 14 (1991), S. 253-263 
    Details
    ISSN: 0930-7516
    Keywords: Chemistry ; Industrial Chemistry and Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: This article describes the effects which occur during three-component mass transfer in liquid-liquid extraction between saturated and undersaturated phases of the system glycerol-acetone-water. The description is based on experiments in a countercurrent spray column. The physical modelling starts with the balance equations of phase flows, taking into account the variation of concentrations and mass flow rates along the column axis as well as backmixing effects. In addition, recent findings on the mechanisms of mass transfer in saturated and undersaturated phasses, deduced from theoretical and experimental results, were used to formulate mass transfer coefficients. These are valid for the region near the interface of drops in a fluid and are inserted into the balance equations. A comparison between experiments and calculations of the observed phenomena is presented.
    Additional Material: 15 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/ceat.270140407
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  • 34
    Electronic Resource
    Electronic Resource
    Photosensitive materials for use in velocity profile measurements in the water phase of air-water systems and in single phase liquid systems (1991)
    Weinheim : Wiley-Blackwell
    Chemical Engineering & Technology - CET 14 (1991), S. 275-287 
    Details
    ISSN: 0930-7516
    Keywords: Chemistry ; Industrial Chemistry and Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Those chemical and photochemical characteristics of a photochromic system which are necessary for successful application to flow visualization studies in water are identified. The properties of a number of photochromic and photosensitive systems are discussed, and critically examined, with regard to these requirements.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/ceat.270140410
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  • 35
    Electronic Resource
    Electronic Resource
    Simulation of a distillation column on an IBM PC, accounting for real behaviour of electrolyte solutionsPaper presented by A. Bosen at the “Jahrestreffen der Verfahrens-Ingenieure”, Stuttgart, October 3 to 5, 1990. (1991)
    Weinheim : Wiley-Blackwell
    Chemical Engineering & Technology - CET 14 (1991), S. 295-300 
    Details
    ISSN: 0930-7516
    Keywords: Chemistry ; Industrial Chemistry and Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: This contribution demonstrates the possibility of using a thermodynamic description of electrolyte solutions directly for computer simulation of distillation columns. Coefficients are determined for a combination of a solvation model with a local composition equation for the activity coefficient. The use of one set of coefficients yields good results of calculation of vapour pressure, vapour phase composition and caloric data of hydrochloric acid. Solution of material and heat balance equations of distillation columns is achieved on an IBM PC with the above description. Two illustrative examples of an absorption and a rectification calculation are presented
    Additional Material: 12 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/ceat.270140502
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  • 36
    Electronic Resource
    Electronic Resource
    Calculation methods for multicomponent adsorption equilibriaPaper presented by S. Scholl at the “Jahrestreffen der Verfahrens-Ingenieure”, Stuttgart, October 2 to 5, 1990. (1991)
    Weinheim : Wiley-Blackwell
    Chemical Engineering & Technology - CET 14 (1991), S. 311-324 
    Details
    ISSN: 0930-7516
    Keywords: Chemistry ; Industrial Chemistry and Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: The knowledge of multicomponent adsorption equilibria is of great importance for the industrial design and application of adsorptive purification and separation processes. As the experimental determination of the required data is time-consuming and costly, theoretical help is desirable. This contribution presents and assesses the most common theoretical approaches to the calculation of multicomponent adsorption equilibria. The models are based on the assumption of an adsorbed solution, extension of the volume filling of micropores theory or statistical thermodynamics. These models are applied to different adsorptive/adsorbent systems with ideal and non-ideal equilibrium behaviour. It is established that, at low coverages of adsorbent surfaces, all theories provide good estimates of the adsorbed phase composition and total loading while, at high saturations, no model is completely satisfactory.
    Additional Material: 7 Ill.
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    URL: http://dx.doi.org/10.1002/ceat.270140505
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    Theoretical analysis of gas stripping performance of spray towers (1991)
    Weinheim : Wiley-Blackwell
    Chemical Engineering & Technology - CET 14 (1991), S. 347-352 
    Details
    ISSN: 0930-7516
    Keywords: Chemistry ; Industrial Chemistry and Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: A simplified model has been developed to describe ammonia stripping process in spray towers. The effect of various operating parameters including air flow rate, contact time, droplet size, liquid to gas ratios and tower height on the performance of such systems has been studied in detail. The results obtained for ammonia stripping have been compared with the limited experimental data available in literature. The predicted results agree reasonably well with the reported experimental data.
    Additional Material: 7 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/ceat.270140508
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  • 38
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    Particle structure change of CaO during high temperature sulphatization (1991)
    Weinheim : Wiley-Blackwell
    Chemical Engineering & Technology - CET 14 (1991), S. 357-362 
    Details
    ISSN: 0930-7516
    Keywords: Chemistry ; Industrial Chemistry and Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: The effects of particle size (layer thickness), BET surface area and pore size distribution on the reactivity of CaO derived from limestone were studied by using a pH-stat and the BET method. Visual analysis was obtained with SEM, and X-ray diffraction was used to determine the crystalline components present. It was found that the pore size distribution, including pore volume and pore surface distribution, affected the sulphatization behaviour. The larger pores (D 〉 50 Å) with their pore volume and pore surface were to some extent responsible for both initial reactivity and ultimate capacity of CaO.
    Additional Material: 19 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/ceat.270140510
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  • 39
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    Infinite-dilution activity coefficients of organic solutes in methyl phenyl ether, butyl ether and methyl iso-butyl ketone (1991)
    Weinheim : Wiley-Blackwell
    Chemical Engineering & Technology - CET 14 (1991), S. 376-378 
    Details
    ISSN: 0930-7516
    Keywords: Chemistry ; Industrial Chemistry and Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Activity coefficients of hydrocarbons and chloroparaffins at infinite dilution in methyl phenyl ether, butyl ether and methyl iso-butyl ketone at 293.15 K have been obtained by the retention-time method in a modified gas chromatograph. The experimental data are compared with predictions of the UNIFAC and MOSCED models. Selectivities for the 1,1,1-trichloroetane-1,2-dichloroetane separation process are reported.
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/ceat.270140603
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  • 40
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    Equilibrium model for CO2 absorption in an aqueous solution of 2-amino-2-methyl-1-propanolRevised form of a paper presented at the 40th Annual Laurance Reid Gas Conditioning Conference, University of Oklahoma, Norman, Oklahoma, March 5-7, 1990. (1991)
    Weinheim : Wiley-Blackwell
    Chemical Engineering & Technology - CET 14 (1991), S. 394-398 
    Details
    ISSN: 0930-7516
    Keywords: Chemistry ; Industrial Chemistry and Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: A semi-empirical gas-liquid equilibrium model for the absorption of CO2 in aqueous 3M AMP (2-amino-2-methyl-1-propanol) is presented. It applies to high CO2 loadings (y 〉 0.5) in the temperature range between 20 and 50 °C, and is based on experimental solubility and pH determinations. For a given amine concentration, it yields the equilibrium partial pressure of CO2 as a function of only two variables: the CO2 loading and temperature. The model correlates the expressions for the chemical equilibria involved as follows: pCO2 = m y × 10x, where pCO2 is the equilibrium partial pressure, x = logK - pH, m is the amine molarity, y the CO2 loading, and K is a parameter involving Henry's law constant, H, and the first dissociation constant, K1, of carbonic acid. pH is found to depend on both temperature and CO2 loading while logK depends only on the CO2 loadIng. Correlations for pH and logK are presented. The model fits own data for 3M AMP very well as well as the equilibrium data found in recent literature.
    Additional Material: 5 Ill.
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    URL: http://dx.doi.org/10.1002/ceat.270140606
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    Characterizing the Structure of Fumed Pigments using the concepts of fractal geometryDedicated Professor Kurt Lesconski on the occasion of his 60th birthday (1991)
    Weinheim : Wiley-Blackwell
    Particle and Particle Systems Characterization 8 (1991), S. 63-71 
    Details
    ISSN: 0934-0866
    Keywords: Chemistry ; Industrial Chemistry and Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Many commercially important pigments such as titanium dioxide and carbonblack are produced as fumes from a combustion process. The fuming process generates open structured agglomerates conforming to a morphology predicated by physical considerations. For this reason widely different chemical pigments often manifest common physical structure. This structure can be characterized using the concepts of fractal geometry. In this communication the potential usefulness and physical significance of descriptive parameters of the agglomerate structure of fumed pigments based on the concepts of fractal geometry are explored. Similar structures present in high energy ceramic powders are discussed and the potential importance of fractal dimension parameters for the prediction of the physical behaviour of powders is outlined.
    Additional Material: 14 Ill.
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    URL: http://dx.doi.org/10.1002/ppsc.19910080112
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  • 42
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    Particle Growth by Coalescence and AgglomerationDedicated to Professor Kurt Leschonski on the occasion of his 60th birthday (1991)
    Weinheim : Wiley-Blackwell
    Particle and Particle Systems Characterization 8 (1991), S. 86-89 
    Details
    ISSN: 0934-0866
    Keywords: Chemistry ; Industrial Chemistry and Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Process Engineering, Biotechnology, Nutrition Technology
    Notes: A dispersed system is considered which will form its condensed phase at high temperatures and is characterized by a high density of very small supercritical nuclei. It is assumed that particle growth is determined by coagulation and (viscous flow) coalescence. The morphology of the final particles depends on the temperature history of the formation process. Compact spherical particles and agglomerates may be formed. Agglomerates result when the process temperature decreases to an extent that coalescence is quenched in the course of the growth process. The average size of the primary particles in the agglomerates is calculated by using the analysis and the approximations described in a previous paper. The growth kinetics of the primary particles are presented in a dimensionless form. The results show that the dimensionless size of the primary particles depends only on the ratio of two characteristic lengths of the system. For small values of this ratio, the size of the primary particles composing the agglomerates, although much greater than the initially formed nuclei, is independent of the volume fraction of the condensed aerosol. For large values of this parameter, the theory merges into the classical theory of perfectly coalescing spheres.
    Additional Material: 2 Ill.
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    URL: http://dx.doi.org/10.1002/ppsc.19910080115
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  • 43
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    Announcement (1991)
    Weinheim : Wiley-Blackwell
    Particle and Particle Systems Characterization 8 (1991), S. 100-100 
    Details
    ISSN: 0934-0866
    Keywords: Chemistry ; Industrial Chemistry and Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Process Engineering, Biotechnology, Nutrition Technology
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/ppsc.19910080118
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    An Estimate of Some Statistical Properties of Extinction signals in dilute and concentrated suspensions of monosized spherical particlesDedicated to Professor Kurt Leschonski on the occasion of his 60th birthday (1991)
    Weinheim : Wiley-Blackwell
    Particle and Particle Systems Characterization 8 (1991), S. 95-99 
    Details
    ISSN: 0934-0866
    Keywords: Chemistry ; Industrial Chemistry and Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Process Engineering, Biotechnology, Nutrition Technology
    Notes: A statistical analysis is made for the extinction of radiations in suspensions, whereby the whole range of possible particle concentrations is covered. The extinction signals are characterized by their average value and by a characteristic length of fluctuation. For simplicity, the considerations are restricted to geometric ray propagation in dispersions of perfectly absorbent, monosized spherical particles. An extinction equation is derived, which reduces to Lambert-Beer's law in the limit of low particle concentrations. For higher concentrations, significant deviations from Lamberg-Beer's law due to steric particle-particle interactions are predicted. The characteristic length of the fluctuations is a function of particle diameter and transmission and has a broad minimum with medium transmissions, allowing for maximum resolution with measurements in this range.
    Additional Material: 6 Ill.
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    URL: http://dx.doi.org/10.1002/ppsc.19910080117
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  • 45
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    The Analysis of Dust Cake Structures (1991)
    Weinheim : Wiley-Blackwell
    Particle and Particle Systems Characterization 8 (1991), S. 105-109 
    Details
    ISSN: 0934-0866
    Keywords: Chemistry ; Industrial Chemistry and Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Process Engineering, Biotechnology, Nutrition Technology
    Notes: The operational characteristics of cake-forming filter apparatus are strongly influenced by the structure of the dust cake formed. The quantitative evaluation of sectional images of loosely bound filter cake deposits is introduced. First the techniques with which the dust cake is prepared and with which scanning electron micrographs may be obtained are described, together with the subsequent digitization by video and computer equipment. This is followed by a comprehensive description of the evaluation of the digitized images, with special emphasis on the determination of the deposit's porosity and the computation of the particle and pore-size distributions at selected locations. Finally, results derived from a true filter cake are presented.
    Additional Material: 7 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/ppsc.19910080120
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  • 46
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    Influence of the Particle Size Distribution on the flow behaviour of fine powders (1991)
    Weinheim : Wiley-Blackwell
    Particle and Particle Systems Characterization 8 (1991), S. 101-104 
    Details
    ISSN: 0934-0866
    Keywords: Chemistry ; Industrial Chemistry and Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Some results are presented of investigations on the flow behaviour of very fine α-alumina powders having different particle size distributions. Shear tests were performed in a translation shear cell. The humidity was in the range 0.3 〈 pD/pSD 〈 0.6 in order to ensure the formation of adsorbed water layers only and to exclude capillary condensation. In the region of adsorbed layer bondings, the flow behaviour of very fine powders deteriorates in comparison with regions where no adsorption layers exist. An extrapolation of the unconfined yield strength for very low consolidation stresses results in an approximately constant value for different particle size distributions. In contrast, the slope of the linear function σc = f (σ1) increases with decreasing particle size up to a certain limit. For narrow particle size distributions, there is a pronounced decrease in the bulk density with decreasing particle size. Further, the bulk density is strongly influenced by the width of the distribution.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/ppsc.19910080119
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  • 47
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    Sieving Capture of Liquidborne Particles by microporous membrane filtration media (1991)
    Weinheim : Wiley-Blackwell
    Particle and Particle Systems Characterization 8 (1991), S. 142-150 
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    ISSN: 0934-0866
    Keywords: Chemistry ; Industrial Chemistry and Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Test methodology has been developed to measure the particle removal efficiency of microporous membrane filtration media under conditions in which sieving is the dominant particle capture mechanism. The methodology was used to determine the particle capture efficiency of a 0.45 μm membrane filter for removal of submicrometer sized particles from DI water. Particle capture was found to be a strong function of particle diameter, filter media thickness, and filter loading. Particle removal efficiency increased with increasing particle diameter and media thickness. It decreased with increased filter loading when the filters were challenged with the smaller particles used in this study. Removal efficiency initially decreased then subsequently increased during loading with larger particles. Capture was independent of filtration velocity and particle concentration. A sieving model was developed to predict particle capture by the filter media as a function of particle diameter, filter thickness and filter loading. The model was found to accurately predict breakthrough of monodisperse particle suspensions through the media. Particle breakthrough occurred more slowly than predicted when the filters were challenged with a polydisperse particle suspension.
    Additional Material: 15 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/ppsc.19910080126
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  • 48
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    Announcement (1991)
    Weinheim : Wiley-Blackwell
    Particle and Particle Systems Characterization 8 (1991), S. 173-173 
    Details
    ISSN: 0934-0866
    Keywords: Chemistry ; Industrial Chemistry and Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Process Engineering, Biotechnology, Nutrition Technology
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/ppsc.19910080131
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  • 49
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    The Work of the British Standards Institution in Particle, surface and pore size characterisationPresented at the Coulter Classics Symposium, Solihull, September 26-27, 1989. (1991)
    Weinheim : Wiley-Blackwell
    Particle and Particle Systems Characterization 8 (1991), S. 170-172 
    Details
    ISSN: 0934-0866
    Keywords: Chemistry ; Industrial Chemistry and Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Process Engineering, Biotechnology, Nutrition Technology
    Notes: British Standards committee GME/29/4 is concerned with “Particle sizing methods other than sieving”. Its work covers not only particle size distribution analysis but also methods of estimation of surface area and pore size distribution, as well as a glossary of terms relevant to those subjects. The current British Standards in the BS 3406 series (particle size analysis) and BS 4359 series (surface area) are reviewed, and a progress report is given on the status of several new and revised Standards which are in preparation.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/ppsc.19910080130
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  • 50
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    A Procedure for Blending and Mass Balancing fine particle size data (1991)
    Weinheim : Wiley-Blackwell
    Particle and Particle Systems Characterization 8 (1991), S. 164-169 
    Details
    ISSN: 0934-0866
    Keywords: Chemistry ; Industrial Chemistry and Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Process Engineering, Biotechnology, Nutrition Technology
    Notes: An increased interest in the development of new techniques for fine grinding has resulted in a growing concern over the accuracy of size distributions for extremely fine particles. Since most particle size analyzers have lower detection limits, care must be taken when comparing size distributions which have not been properly mass balanced.An automated technique has been developed in which a completely mass balanced size distribution can be obtained using an Elzone 80XY particle size analyzer. A computer program is used to blend the data from successively smaller orifice tubes, and to determine the weight percent of material finer than the lower detection limit of the analyzer. This result is then used to correct the distribution for the missing fine material. Experimental results indicate that size distributions obtained using this procedure are reproducible and compare favorably with those obtained using other size analysis techniques.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/ppsc.19910080129
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  • 51
    Electronic Resource
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    Announcement (1991)
    Weinheim : Wiley-Blackwell
    Particle and Particle Systems Characterization 8 (1991), S. 173-174 
    Details
    ISSN: 0934-0866
    Keywords: Chemistry ; Industrial Chemistry and Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Process Engineering, Biotechnology, Nutrition Technology
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/ppsc.19910080132
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    Development of an Automatic System for Measuring Particle Charge and Size distributions in a clean room (1991)
    Weinheim : Wiley-Blackwell
    Particle and Particle Systems Characterization 8 (1991), S. 200-208 
    Details
    ISSN: 0934-0866
    Keywords: Chemistry ; Industrial Chemistry and Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Process Engineering, Biotechnology, Nutrition Technology
    Notes: An automatic measuring system was developed to perform simultaneous measurements of particle size and charge distributions in a clean room and other aerosol sources. The system consists of an electrostatic condenser (EC) and an optical particle counter (OPC), which are controlled by a personal computer (PC). The PC automatically varies the voltage on the EC and converts the corresponding OPC counts to charge distributions. The reliabilities of the data inversion method and the automatic measuring system were confirmed by theoretical and experimental examinations, respectively. In the theoretical examination, inverted charge distributions were tested and compared with various assumed input distributions. In the experiment where monodisperse aerosols neutralized by a 85Kr neutralizer were used, the measurement results agreed well with the theoretical Boltzmann charge distribution. The application of this technique is demonstrated by the measurement of charge and size distributions of aerosols in a clean room.
    Additional Material: 14 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/ppsc.19910080137
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  • 53
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    A Comparative Study on Different Scattering Techniques and data evaluation methods for sizing of colloidal systems using light scattering (1991)
    Weinheim : Wiley-Blackwell
    Particle and Particle Systems Characterization 8 (1991), S. 274-281 
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    ISSN: 0934-0866
    Keywords: Chemistry ; Industrial Chemistry and Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Quasi-elastic light scattering, elastic light scattering and Fraunhofer diffraction can be used for optical particle sizing. Simulated data were used to compare the different scattering techniques in terms of resolution and range of applicability. Elastic scattering techniques have a ten times higher resolution but cover a smaller size range than quasi-elastic light scattering. The most important inversion techniques for data evaluation for such experiments were also compared. Regularization techniques with positivity constraints and interpolating cubic B-splines proved to be superior to truncated singular value decomposition and maximum entropy methods.
    Additional Material: 8 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/ppsc.19910080150
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  • 54
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    Measurement of Polydisperse Colloidal Suspensions with quasielastic light scattering (1991)
    Weinheim : Wiley-Blackwell
    Particle and Particle Systems Characterization 8 (1991), S. 259-266 
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    ISSN: 0934-0866
    Keywords: Chemistry ; Industrial Chemistry and Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Process Engineering, Biotechnology, Nutrition Technology
    Notes: The measurement of polydisperse populations of colloidal particles with quasielastic light scattering (QLS) is a common and dangerous practice. Here intensity autocorrelation functions with different linewidth distributions are simulated. The simulated data are treated with the histogram and exponential sampling methods and the results are contrasted with the results of the Laplace inversion routine of Provencher. All methods work well in calculating the size distribution from noise-free correlation functions. In analyzing noisy data the methods may produce results that bear no relation to the true size distribution. The histogram method fails to determine size distributions from noisy simulated and real correlation functions. The exponential sampling method gives a qualitative measure of the size distribution when the required resolution does not exceed the limitations set by noise theory. Provencher's routine extracts smooth unimodal distributions very accurately even from noisy correlation functions, but determination of bimodal distributions may be unreliable. The importance of taking data at many scattering angles is emphasized and experimentally determined size distributions of samples of polystyrene latex spheres measured at multiple scattering angles are presented.
    Additional Material: 7 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/ppsc.19910080148
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    The Physically Relevant Parameter Space of the Nukiyama-Tanasawa distribution function (1991)
    Weinheim : Wiley-Blackwell
    Particle and Particle Systems Characterization 8 (1991), S. 287-293 
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    ISSN: 0934-0866
    Keywords: Chemistry ; Industrial Chemistry and Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Process Engineering, Biotechnology, Nutrition Technology
    Notes: The range of the parameters of the Nukiyama-Tanasawa distribution function was analysed, leading to the identification of the physically relevant parameter space. The analysis was also applied to the Rosin-Rammler distribution function.
    Additional Material: 2 Ill.
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    URL: http://dx.doi.org/10.1002/ppsc.19910080152
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  • 56
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    Regularized Inversion of the Laplace Transform: Accuracy of analytical and discrete inversion (1991)
    Weinheim : Wiley-Blackwell
    Particle and Particle Systems Characterization 8 (1991), S. 282-286 
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    ISSN: 0934-0866
    Keywords: Chemistry ; Industrial Chemistry and Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Dynamic light scattering is a technique used for the optical determination of a colloidal particle size distribution. A simple procedure, based on a trapezoidal model for the linewidth distribution function, is given for obtaining a constrained regularized inversions of correlation data obtained in dynamic light scattering experiments, and estimating the accuracy of such inversions. Based on the eigenfunction decomposition of the Laplace integral equation, error bars, which are directly related to the accuracy of the correlation data, may be placed on both analytical and discrete inversions. By using a regularization procedure, and a nonnegativity constraint, problems with statistical noise in data may be handled effectively.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/ppsc.19910080151
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    Mass Calibration of the Coulter Counter Model ZM (1991)
    Weinheim : Wiley-Blackwell
    Particle and Particle Systems Characterization 8 (1991), S. 294-296 
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    ISSN: 0934-0866
    Keywords: Chemistry ; Industrial Chemistry and Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Process Engineering, Biotechnology, Nutrition Technology
    Notes: The calibration of electrical sensing zone instruments is normally achieved by using spherical particles with a certified size. An alternative and more fundamental procedure, known as mass or self-calibration, is to use particles of the material under test.This work concerns the mass calibration technique, in particular the equations used to calculate the mass calibration constant. It is demonstrated that some of the published expressions are inconsistent. An expression particularly suitable for the Coulter Counter Model ZM has been derived and validated. Some experiments were also performed using irregular particles, in order to compare both calibration methods.
    Additional Material: 1 Ill.
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    URL: http://dx.doi.org/10.1002/ppsc.19910080153
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    Control and Use of a Miniaturized Droplet Generator (1991)
    Weinheim : Wiley-Blackwell
    Particle and Particle Systems Characterization 8 (1991), S. 297-300 
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    ISSN: 0934-0866
    Keywords: Chemistry ; Industrial Chemistry and Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Process Engineering, Biotechnology, Nutrition Technology
    Notes: A miniaturized droplet generator with some new features, working on the principle of laminar liquid jet instability and break-up was designed. The instrument has been used to study the dispersion of monosized droplets in a turbulent swirling flow, exhibiting the main features of combustion chamber flows of modern gas turbines.The operating range of the generator was evaluated by phase-Dopper anemometry (PDA). It was demonstrated that the device also works in some metastable operating modes, producing coherent droplet streams with very small standard deviations for drop size and drop velocity. Special attention was directed to the reliability of the device and to the control of drop size. The PDA measurements showed that, in contrast to the evaluated optimum excitation frequency, the drop size cannot be determined from the orifice diameter.
    Additional Material: 3 Ill.
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    URL: http://dx.doi.org/10.1002/ppsc.19910080154
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    Design Data for Cyclones (1991)
    Weinheim : Wiley-Blackwell
    Particle and Particle Systems Characterization 8 (1991), S. 301-307 
    Details
    ISSN: 0934-0866
    Keywords: Chemistry ; Industrial Chemistry and Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Process Engineering, Biotechnology, Nutrition Technology
    Notes: For many years efforts have been made to describe the complex process of particle separation in cyclones, and a multitude of separation models have been set up. A comparison of such separation models fails because insufficient usable test results are available and systematic and precise investigations are missing.It is important for the design of cyclones to rate their separation properties by means of the fractional collection efficiency. On account of the known measuring problems, the data supply of reliable fractional efficiency curves of cyclones is still too small. Fractional efficiency as a function of the entrance velocity was measured with a high-speed optical measuring technique. Measurements of low dust concentrations are presented. Geometrically similar cyclones of four different sizes were investigated. The fractional efficiency curves are plotted versus dimensionless parameters and the validity of the design criteria gained in this way is shown. The influence of particle shape on the fractional efficiency curves is discussed.
    Additional Material: 11 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/ppsc.19910080155
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    Announcement (1991)
    Weinheim : Wiley-Blackwell
    Particle and Particle Systems Characterization 8 (1991), S. 323-323 
    Details
    ISSN: 0934-0866
    Keywords: Chemistry ; Industrial Chemistry and Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Process Engineering, Biotechnology, Nutrition Technology
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/ppsc.19910080158
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  • 61
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    Performance of Disposable Respirators (1991)
    Weinheim : Wiley-Blackwell
    Particle and Particle Systems Characterization 8 (1991), S. 308-314 
    Details
    ISSN: 0934-0866
    Keywords: Chemistry ; Industrial Chemistry and Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Process Engineering, Biotechnology, Nutrition Technology
    Notes: An experimental study of the filtration performance of several commercially available, NIOSH-approved, disposable respirators was conducted using monodisperse DOP and NaCl particles with diameters in the 0.035 to 4 μm range.The aerosol penetration through the respirators were measured at flow rates of 16, 28 and 48 L/m using a condensation nucleus counter, an aerodynamic particle sizer, and a laser optical particle counter for purposes of comparison. The results obtained by these instruments were found to be in good agreement with each other in the overlapping region of particle size of the instruments.The peak penetration through the respirator filters was found to range from approximately 1.2% to 30% at 16 L/m, 3.5% to 37% at 28 L/m, and 6% to 45% at 48 L/m. The most penetrating particle size was found to lie in the 0.1 to 0.4 μm diameter range. Further, no significant difference in penetration for NaCl and DOP particles was found, suggesting that the particlebounce effect was not important in the present study.
    Additional Material: 15 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/ppsc.19910080156
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  • 62
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    Drop coalescence on inclined plates in liquidsDedicated to Professor Kurt Dialer on the occasion of his 70th birthday (1991)
    Weinheim : Wiley-Blackwell
    Chemical Engineering & Technology - CET 14 (1991), S. 11-19 
    Details
    ISSN: 0930-7516
    Keywords: Chemistry ; Industrial Chemistry and Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Inclined plates are often installed as mechanical separation aids in gravity settlers for the separation of liquid-liquid systems. The authors investigated the process of coalescence of single drops on trickling films flowing off inclined plates. The method of investigation was developed by Blass and Rautenberg. It ensures that, under certain conditions, only hydrodynamic parameters influence the coalescence process to any significant extent. The coalescence time of the drops characterizes the process of coalescence. Short time between 1 and 3 seconds provide favourable conditions for coalescence whereas long times, often ten times as long or even longer are unfavourable. This contribution introduces a criterion for clear demarcation between these two ranges and also a determination of separation parameters for favourable conditions for coalescence. Furthermore, the function of the plates is described, which is determined by hydrodynamic and wetting processes. The characteristic operating regions of a plate are shown in a working diagram.
    Additional Material: 13 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/ceat.270140103
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    Effect of mixing behaviour on gas-liquid mass transfer in highly viscous, stirred non-newtonian liquidsPaper presented at the “Jahrestreffen der Verfahrens-Ingenieure”, Berlin, September 27 to 29, 1989. (1991)
    Weinheim : Wiley-Blackwell
    Chemical Engineering & Technology - CET 14 (1991), S. 1-10 
    Details
    ISSN: 0930-7516
    Keywords: Chemistry ; Industrial Chemistry and Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: When declaring and using process engineering data such as, for exmple, mixing times or kLa values, it is assumed that these apply to the entire reactor contents. The condition of uniform mixing, necessary for this, is generally met in the regime of turbulent flow. When highly viscous and, above all, strongly non-Newtonian liquids are stirred in small reactors, there are frequently also regions of laminar flow and completely stagnant zones, which are only partially mixed or not at all. The present paper pursues the question to what extent is the gas-liquid mass transfer in stirred, highly non-Newtonian liquids influenced by the mixing behaviour of the reactor. The results show that, below certain Reynolds numbers, three relatively distinct regions exist, with different mixing intensities. Between an almost ideally mixed region in the vicinity of the stirrer and a completely stagnant and dead one, there is a zone of very slight motion. This finding demonstrates that the usual determination of integral or volume-based data in the literature is neither logical nor adequate for the case under consideration. Thus, the gas-liquid mass transfer takes place mainly in the relatively well mixed region. Therefore, use of a kLa value also requires the volume of this region to be declared. Only the knowledge of this volume enables us to correlate the kLa values in such a way that the sorption characteristics thus obtained appear suitable for scale-up. This procedure, which is illustrated by numerous examples of measured results for different stirrers, is important whenever design data for highly viscous liquids are to be worked out on the basis of laboratory measurements. Only when larger equipment is used, in which turbulent flow can be achieved, this problem does not arise because of the relatively uniform mixing of reactor contents.
    Additional Material: 20 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/ceat.270140102
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  • 64
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    Modelling of pressure drop in packed columns (1991)
    Weinheim : Wiley-Blackwell
    Chemical Engineering & Technology - CET 14 (1991), S. 89-95 
    Details
    ISSN: 0930-7516
    Keywords: Chemistry ; Industrial Chemistry and Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: The correct choice of packing is of decisive importance for optimum process efficiency in the operation of two-phase countercurrent columns. An important criterion for this choice is the pressure drop in the gas flow. Theoretical relationships are derived for calculating the pressure drop in beds with dry and trickle packings. It has been demonstrated by comprehensive experiments that these relationships allow the pressure drop to be determined more accurately than by previous methods. The experiments were performed at the Department of Thermal Separation Processes of Bochum University on 54 different packed beds, using 24 different systems.
    Additional Material: 7 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/ceat.270140203
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  • 65
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    Calo-visco-densimeter: A multipurpose apparatusPaper presented by H. Zech at the “Jahrestreffen der Verfahrens-Ingenieure”, Berlin, September 27 to 29, 1989.Dedicated to Professor Dr.-Ing. Karl Stephan on the occasion of his 60th birthday (1991)
    Weinheim : Wiley-Blackwell
    Chemical Engineering & Technology - CET 14 (1991), S. 109-113 
    Details
    ISSN: 0930-7516
    Keywords: Chemistry ; Industrial Chemistry and Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: A multipurpose apparatus was designed, built and operated with the aim of a simultaneous determination of enthalpy of mixing, heat capacity, kinematic viscosity and density of liquid mixtures at 240 〈 T 〈 370 K and 1 〈 p 〈 25 bar. Its operation was monitored by a PC. Details of design and the first experimental results are presented.
    Additional Material: 10 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/ceat.270140207
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    Application of dynamic programming to high-dimensional systems described by difference equationsPaper presented by R. Luus at the Second North American/German Workshop on Chemical Engineering Mathematics and Computation, Göttingen, Germany, July 15-20, 1990. (1991)
    Weinheim : Wiley-Blackwell
    Chemical Engineering & Technology - CET 14 (1991), S. 122-126 
    Details
    ISSN: 0930-7516
    Keywords: Chemistry ; Industrial Chemistry and Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: The application of dynamic programming using an interative procedure, which employs domain contraction and accessible grid points for the state vector, is investigated for solving optimal control problems where the system is described by a set of difference equations. A model of a gas absorber with six state variables and two control variables is used to examine the feasibility of the proposed algorithm and to analyze the effects of the grid size and of the domain contraction factor. This algorithm yields rapid convergence to the optimum even when a relatively coarse grid with as few as 11 grid points is used.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/ceat.270140210
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    Masthead (1991)
    Weinheim : Wiley-Blackwell
    Chemical Engineering & Technology - CET 14 (1991) 
    Details
    ISSN: 0930-7516
    Keywords: Chemistry ; Industrial Chemistry and Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/ceat.270140301
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  • 68
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    Studies of drop break-up in liquid-liquid systems in a rotating disc contactor. Part II: Effects of mass transfer and scale-up (1991)
    Weinheim : Wiley-Blackwell
    Chemical Engineering & Technology - CET 14 (1991), S. 178-185 
    Details
    ISSN: 0930-7516
    Keywords: Chemistry ; Industrial Chemistry and Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: The number fraction of drops of a given size which break up at rotor level in a rotating disc contactor has been observed during mass transfer in either direction to or from solvent or aqueous drops. Critical rotor speeds for a given drop size undergoing mass transfer can be used to find an effective interfacial tension. Using this interfacial tension value, the break-up fractions are correlated within experimental uncertainties in the same manner as for no mass transfer. Drop break-up fractions depend on column size and relevant empirical correlations of the data are presented. The results may be used to estimate the effect of mass transfer on drop size distributions in an RDC.
    Additional Material: 17 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/ceat.270140305
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    Non-steady-state catalytic decontamination of waste gases (1991)
    Weinheim : Wiley-Blackwell
    Chemical Engineering & Technology - CET 14 (1991), S. 209-212 
    Details
    ISSN: 0930-7516
    Keywords: Chemistry ; Industrial Chemistry and Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: The non-steady-state behaviour of a fixed bed reactor controlled by periodical direction reversal of reactant feed, applied in catalytic oxidation of industrial waste gases, containing organic compounds and carbon monoxide, has been investigated. The effects of the type of oxidized compound, its initial feed concentration, linear gas velocity, inerts-to-catalyst ratio and inerts thermophysical characteristics on the formation of reactor concentration and temperature fields were elucidated. It was shown that autothermal reactor behaviour is guaranteed by concentrations of the oxidized component which ensure an adiabatic temperature increase in excess of 20 °C. Deviations of either flow rate or initial concentration of the oxidized compound do not disturb the operational stability.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/ceat.270140309
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  • 70
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    Influence of intraparticle total pressure change on pore mass transportExtended version of poster presented by S. Scholl at the “Jahrestreffen der Verfahrens-Ingenieure”, Berlin, September 27 to 29, 1989. (1991)
    Weinheim : Wiley-Blackwell
    Chemical Engineering & Technology - CET 14 (1991), S. 213-218 
    Details
    ISSN: 0930-7516
    Keywords: Chemistry ; Industrial Chemistry and Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Influence of intraparticle total pressure change on pore mass transport is investigated in physical gas phase adsorption of a single component from an inert carrier medium. The Dusty Gas Model is applied to quantify pore mass transport, assuming local equilibrium between pore fluid and adsorbed phase. Calculated results for single pellet adsorption kinetics of cyclohexane on activated carbon and CO2 on molecular sieve 5 Å are compared with experimental data. It is found that the total pressure drop in the pore system may be as much as 1% of the ambient total pressure. This results in a maximum viscous flow contribution of 13% for the cases studied. Since this contribution is obtained only under conditions of low overall transport rates of the adsorbed component, the assumption of isobaric conditions within the pore system of a porous adsorbent appears justified for most cases of practical calculations.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/ceat.270140310
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    On the falling-rate period (1991)
    Weinheim : Wiley-Blackwell
    Chemical Engineering & Technology - CET 14 (1991), S. 234-239 
    Details
    ISSN: 0930-7516
    Keywords: Chemistry ; Industrial Chemistry and Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: A fixed bed of glass particles, wetted with water, was dried from above. The measured moisture profiles within the sample show that its surface is not completely dry during the falling-rate period. Hence, the current view, according to which the moisture front retreats into the sample directly after reaching the critical moisture content, has to be revised. Assuming that parallel dry and wet channels form within the sample during the constant-rate period, the onset of the falling-rate period depends only on the diameter of these channels. If the moisture is distributed very finely, a large number of channels with a small diameter have to be considered. The falling-rate period for this system occurs at low moisture contents. For a coarse distribution of moisture, fewer channels with a large diameter should be assumed. Their drying rates show the beginning of the falling-rate period already at high moisture contents. A good agreement between measured and calculated drying rates could be achieved by fitting the channel diameter. Only for very low moisture contents, is the agreement poor. This is to be expected, because the measured moisture profiles show a completely dry sample surface for these moisture contents, indicating that the moisture front has already retreated into the sample.
    Additional Material: 10 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/ceat.270140404
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    An automatic laboratory reactor for homogeneous polymerization of methyl methacrylatePaper presented by U. Budde at the “Jahrestreffen der Verfahrens-Ingenieure”, Berlin, September 27 to 29, 1989. (1991)
    Weinheim : Wiley-Blackwell
    Chemical Engineering & Technology - CET 14 (1991), S. 134-140 
    Details
    ISSN: 0930-7516
    Keywords: Chemistry ; Industrial Chemistry and Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: An automatic stirred tank reactor of laboratory scale has been developed for on-line measurement of conversion, viscosity, and molar mass distribution of homogeneous polymerizations. For these on-line measurements, a fraction of the reaction mixture is bypassed through a densimeter and a viscometer. Samples are taken at intervals of 15 min, diluted semi-automatically, and then injected into a high performance gel permeation chromatograph for determination of the molar mass distribution of the polymers. A microcomputer collects the measured data, calculates the monomer conversion and the output data for different control units. In this study, methyl methacrylate is polymerized batch- and semi-batchwise with ethyl acetate as solvent and in the presence of different initiators. The semi-batch polymerizations are carried out at constant reaction rate by feeding the initiator and at a given increase in viscosity by feeding the solvent.
    Additional Material: 7 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/ceat.270140212
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    Fluidized bed dryers: Dynamic modelling and control (1991)
    Weinheim : Wiley-Blackwell
    Chemical Engineering & Technology - CET 14 (1991), S. 307-310 
    Details
    ISSN: 0930-7516
    Keywords: Chemistry ; Industrial Chemistry and Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Fluidized bed drying finds important applications in the chemical industry on account of the following advantages: (a) rapid exchange of heat and mass between drying media and particles yields the desired product quality and reduces the overall drying time and (b) easy handling of feed and product. There is much scope for improving the existing modelling techniques as applied to predicting the performance characteristics of the dryers. This should provide a sound basis for the implementation of appropriate control strategies. This report is a review of prevailing modelling, identification techniques and control strategies. Hopefully, the up to date information in this paper will be found useful for research work on fluidized bed dryIng.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/ceat.270140504
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    Simulation of fluidized-bed reactors for catalytic oxidative coupling of methane to C2-hydrocarbonsPaper presented at the “Jahrestreffen der Verfahrens-Ingenieure”, Stuttgart, October 3 to 5, 1990.Dedicated to Professor Dr. Dr. h.c. Dieter Behrens on the occasion of his 65th birthday (1991)
    Weinheim : Wiley-Blackwell
    Chemical Engineering & Technology - CET 14 (1991), S. 325-333 
    Details
    ISSN: 0930-7516
    Keywords: Chemistry ; Industrial Chemistry and Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: The “bubble assemblage model” of Kato and Wen was applied to simulate the catalytic oxidative coupling of methane to C2-hydrocarbons in a fluidized bed reactor. Simulation results were compared to experimental data obtained in a laboratory-scale fluidized bed reactor. To improve the accuracy of predictions, the influence of fluid bed hydrodynamic and kinetic submodels was investigated by applying a sensitivity analysis. It was shown that the most important element in the model is the applied reaction scheme; the consecutive reactions of C2 hydrocarbons occurring most probably in the gas phase should be considered.
    Additional Material: 13 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/ceat.270140506
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    Sensitivity analysis in static optimization of fermentation plantsPaper presented at the “Jahrestreffen der Verfahrens-Ingenieure”, Stuttgart, October 3 to 5, 1990. (1991)
    Weinheim : Wiley-Blackwell
    Chemical Engineering & Technology - CET 14 (1991), S. 353-356 
    Details
    ISSN: 0930-7516
    Keywords: Chemistry ; Industrial Chemistry and Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Biotechnological processes are often characterized by uncertain model parameters, input variables which are difficult to handle and ill defined cost functions. Nevertheless, it is desirable to define optimal operating points. Starting with a robust approach for numerical optimization, the paper presents three different methods for evaluating the sensitivity of an optimal operating point to uncertain parameters or disturbances of the input variables. It is shown that sensitivity analysis can provide useful guidelines for designing biotechnical plants with invariant optimum operation in the presence of changing inputs or parameters.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/ceat.270140509
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  • 76
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    Method of multiobjective optimization for imprecise objectives (1991)
    Weinheim : Wiley-Blackwell
    Chemical Engineering & Technology - CET 14 (1991), S. 363-366 
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    ISSN: 0930-7516
    Keywords: Chemistry ; Industrial Chemistry and Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: A method of multiobjective optimization for imprecise objectives is presented. The problem consisted in a minimization of the distance between the set of admissible solutions and an ideal point. Applicability of the method is illustrated by the choice of best impeller from a group of seven different types tested. The optimum process conditions were selected, taking as optimization objective the maximization of kLa and minimization of PG.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/ceat.270140511
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  • 77
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    A multi-parameter model for absorption (1991)
    Weinheim : Wiley-Blackwell
    Chemical Engineering & Technology - CET 14 (1991), S. 379-385 
    Details
    ISSN: 0930-7516
    Keywords: Chemistry ; Industrial Chemistry and Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: A three-parameter model for mass transfer by absorption, based on a combined effect of non-steady-state molecular and eddy diffusion through a resistance zone has been suggested, which encompasses all the existing theories on mass transfer at the gas-liquid interface. King's approach [5] to describing gas-liquid mass transfer phenomena through an eddy-diffusivity model can explain some experimental results, but does not provide a general mathematical solution of the problem. The shortcomings of the King's model are overcome in the present work and a general solution is presented. This solution confirms the experimental findings of Versteeg et al. [10] for liquid phase mass transfer. The steady-state solution of the present theory, valid for the dimensionless number α 〉 0, shows a close agreement with experimental data of Luk [22], the only source of all the information necessary for model verification.
    Additional Material: 7 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/ceat.270140604
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    Hydrodynamics in a pressurized cocurrent gas-liquid trickle-bed reactor (1991)
    Weinheim : Wiley-Blackwell
    Chemical Engineering & Technology - CET 14 (1991), S. 406-413 
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    ISSN: 0930-7516
    Keywords: Chemistry ; Industrial Chemistry and Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: The influence of gas density on total external liquid hold-up, pressure drop and gas-liquid interfacial area, under trickle-flow conditions, and the transition to pulse flow have been investigated with nitrogen or helium as the gas phase up to 7.5 MPa. It is concluded that the hydrodynamics depends on the gas density and not on the reactor pressure. At higher gas densities, the operating region for trickle flow becomes larger while the gas-liquid interfacial area increases only slightly. Pressure gradient and liquid hold-up are considerably affected by gas density and correlations have been derived for these parameters.
    Additional Material: 7 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/ceat.270140608
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    Masthead (1991)
    Weinheim : Wiley-Blackwell
    Chemical Engineering & Technology - CET 14 (1991) 
    Details
    ISSN: 0930-7516
    Keywords: Chemistry ; Industrial Chemistry and Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/ceat.270140601
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    Impact of particle size dispersity on thermal conductivity of packed beds: Measurement, numerical simulation, predictionPaper presented by E. Tsotsas at the “Jahrestreffen der Verfahrens-Ingenieure”, Stuttgart, October 3 to 5, 1990. (1991)
    Weinheim : Wiley-Blackwell
    Chemical Engineering & Technology - CET 14 (1991), S. 421-427 
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    ISSN: 0930-7516
    Keywords: Chemistry ; Industrial Chemistry and Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: The influence of particle size dispersity on thermal conductivity of packed beds without fluid flow is investigated. For this purpose, new experimental data for bi- and polydispersed packings are presented and data from the literature reviewed. All data are tabulated. The results of numerical calculations carried out for regular arrangements of spheres are also discussed. The impact of particle size dispersity on thermal conductivity is shown to be primarily due to the change in bed porosity. Thus, prediction can be carried out in the same way as for monodispersed packings if based on the actual bed porosity. A model developed by Schlünder and co-workers is revised and recommended for practical application.
    Additional Material: 5 Ill.
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    URL: http://dx.doi.org/10.1002/ceat.270140610
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  • 81
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    Masthead (1991)
    Weinheim : Wiley-Blackwell
    Particle and Particle Systems Characterization 8 (1991) 
    Details
    ISSN: 0934-0866
    Keywords: Chemistry ; Industrial Chemistry and Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Process Engineering, Biotechnology, Nutrition Technology
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/ppsc.19910080101
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    A New Air Classification Principle for the Particle Size range d 〈 5 μmDedicated to Professor Kurt Leschonski on the occasion of his 60th birthday (1991)
    Weinheim : Wiley-Blackwell
    Particle and Particle Systems Characterization 8 (1991), S. 8-11 
    Details
    ISSN: 0934-0866
    Keywords: Chemistry ; Industrial Chemistry and Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Requirements for processes for air classification for the particle size range d 〈 5 μm are described. A classification principle and first experimental results are presented.
    Additional Material: 7 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/ppsc.19910080103
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  • 83
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    Preparation Technology for Fine Particle MeasurementDedicated to Professor Kurt Leschonski on the occasion of his 60th birthday (1991)
    Weinheim : Wiley-Blackwell
    Particle and Particle Systems Characterization 8 (1991), S. 1-7 
    Details
    ISSN: 0934-0866
    Keywords: Chemistry ; Industrial Chemistry and Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Describing the disperse state is important for quality assurance, operational safety and the design and modelling of processes, especially in solids technology. Starting materials, intermediates and end products have to be characterized. Apart from representative sampling, preparation greatly influences the results of particle characterization. Very fine particles are normally agglomerated unless a highly dispersed state is stabilized by an additive. For a meaningful measurement, they must be preserved in this state or be definitely dispersed, depending on the type of problem.If the point of interest is the present disperse state with regard to the processing characteristics, e.g. for a filtration, the system should not be changed by the preparation method. If it is necessary to determine the property functions, i. e. the functional relationship between technological and physical properties, it is necessary in general to use a high dispersion energy or a long dispersing time in order to obtain the best achievable dispersion. The finer and more unstable a disperse phase is, the more the correct processing is important for the result. The problems of dispersion in gases and liquids are discussed with some examples.
    Additional Material: 13 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/ppsc.19910080102
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  • 84
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    Measurement of the Influence of Directed Particle motion on the turbulent particle deposition velocity by means of laser-doppler anemometryDedicated to Professor Kurt Leschonski on the occasion of his 60th birthday (1991)
    Weinheim : Wiley-Blackwell
    Particle and Particle Systems Characterization 8 (1991), S. 12-15 
    Details
    ISSN: 0934-0866
    Keywords: Chemistry ; Industrial Chemistry and Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Process Engineering, Biotechnology, Nutrition Technology
    Notes: The dry deposition of particles from the atmosphere is not well understood for reasons of surface variabilities and mutual interactions between surface and particles. However, even relatively simple influences of physical parameters have so far resisted successful parameterization, although some progress has been achieved. There is no general way to determine the relative contributions of stochastic turbulent and Brownian diffusion and directed motions (i. e. sedimentation) to the total deposition velocity since they contribute in a nonlinear manner to the total deposition velocity. The directed motion is an unknown function of atmospheric turbulence, the particle diffusion coefficient Dp and the sum of all directed particle motions by thermophoresis, diffusiophoresis, photophoresis, electrophoresis, sedimentation etc. Practically nothing is known about the action of the first three forces and even the easily accessible electrophoresis has not been considered relevant for deposition of atmospheric particles. Because it is relatively easy to change an electric field with all other parameters kept constant and measure the absolute difference in total deposition velocity the following experimental Laser-Doppler study was intended to show the feasibility of the field-changing-technique and the magnitude of the effects without quantitatively determining the electrical mobility distribution as a function of particle size.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/ppsc.19910080104
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  • 85
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    Detection and Chemical Characterization of Polycyclic Aromatic Hydrocarbon aerosols by means of laser-induced fluorescenceDedicated to Professor Kurt Leschonski on the occasion of his 60th birthday (1991)
    Weinheim : Wiley-Blackwell
    Particle and Particle Systems Characterization 8 (1991), S. 23-28 
    Details
    ISSN: 0934-0866
    Keywords: Chemistry ; Industrial Chemistry and Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Laser-induced and time-resolved aerosol fluorescence is introduced as an analytical technique for the qualitative and quantitative determination of surface-bound polycyclic aromatic hydrocarbons (PAHs). The analytical figures of merit are evaluated by studying the fluorescent properties (emission wavelengths and temporal behavior) of PAHs adsorbed on submicrometer NaCl particles. In addition to singly adsorbed PAHs on NaCl particles, a three-component PAH adsorbate system is characterized. Detection limits are in the range 5 ng/m3 (e. g. for anthanthrene).
    Additional Material: 7 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/ppsc.19910080106
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  • 86
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    Extended Phase-Doppler System for Characterization of Multiphase FlowsDedicated to Professor Kurt Leschonski on the occasion of his 60th birthday (1991)
    Weinheim : Wiley-Blackwell
    Particle and Particle Systems Characterization 8 (1991), S. 16-22 
    Details
    ISSN: 0934-0866
    Keywords: Chemistry ; Industrial Chemistry and Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Process Engineering, Biotechnology, Nutrition Technology
    Notes: An extended phase-Doppler anemometry (PDA) system is described, which allows the user to measure the refractive index of spherical particles, in addition to their velocity, diameter and concentration. The extended PDA system incorporates two additional detectors on the receiving side. Each particle generates four Doppler signals. Phase shifts between two pairs of signals are recorded. The ratio between two measured values of phase shifts is a function of the particle refractive index. The phase ratio is shown to be fairly independent of particle velocity or diameter.Calculations based on Mie scattering theory demonstrated the feasibility of the concept. Measurements with monosize droplets of glycerine-water mixture, covering the refractive index range 1.33-1.44, were used to verify the theoretical predictions. The instrument was also tested with spray flows.It is also shown how the phase-Doppler technique may be used to distinguish between reflecting and refracting particles. This means that the extended phase-Doppler system may be employed to recognize particle material, and also to measure locally particle velocities, sizes and concentrations, in a multiphase flow with several transparent dispersed phases and one dispersed phase consisting of reflecting particles.
    Additional Material: 9 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/ppsc.19910080105
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  • 87
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    Modern Methods of On-Line Size Analysis for Particulate Process StreamsDedicated to Professor Kurt Leschonski on the occasion of his 60th birthdayThis paper was presented at The Engineering Foundation Conference “Control of Particulate Processes”, Matinkyla, Espoo, Finland, August 13-18, 1989. (1991)
    Weinheim : Wiley-Blackwell
    Particle and Particle Systems Characterization 8 (1991), S. 29-34 
    Details
    ISSN: 0934-0866
    Keywords: Chemistry ; Industrial Chemistry and Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Two techniques for on-line particle size measurement are evaluated on the reproducibility of their volume distribution determinations. A forward scattering laser light devise is interfaced with a dilutor to examine the potential of this technique for high concentration streams. The forward scattering instruments are capable of outputting extremely reproducible distributions and here we show that when the dilutor is well designed, the on-line instrument can have similar performance. We compare this with a scanning back scatter instrument which is directly inserted in highly concentrated slurries. We present the methods used to improve the robustness of the conversion of the output of the back scatter instrument to volume distributions. The output of the back scatter instrument is inherently less stable but with the proper methods one can obtain reproducibilities of the order of 2 to 6 percent.
    Additional Material: 10 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/ppsc.19910080107
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  • 88
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    Particle Size Distribution of Inorganic Colloidal Dispersions: A comparison of different techniques (1991)
    Weinheim : Wiley-Blackwell
    Particle and Particle Systems Characterization 8 (1991), S. 128-135 
    Details
    ISSN: 0934-0866
    Keywords: Chemistry ; Industrial Chemistry and Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Process Engineering, Biotechnology, Nutrition Technology
    Notes: The particle size distributions of a latex and of four different inorganic colloidal systems, consisting of spherical particles suspended in aqueous solutions, have been evaluated by three techniques: electron microscopy (EM, scanning and/or transmission), classical light scattering (CLS, polarization ratio method), and photon correlation spectroscopy (PCS, commercial instrument). Both light scattering techniques appear to be exceedingly sensitive to even a relatively small level of aggregation. Thus, the effect of treating the dispersions by ultrasonic energy was tested in order to establish the best experimental conditions. While a shorter sonication results in a minimum or constant value for the average particle diameter (or the polydispersity of the suspension), longer times may promote reaggregation of particles. Good correlation of the results by different light scattering techniques was found as long as the conversion to number averages of the PCS data involved the proper corrections for polydispersity. The agreement with the EM depended on the chemical nature of the dispersed particles; i.e., drying and exposure to the electron beam greatly affected the histograms in some cases.
    Additional Material: 10 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/ppsc.19910080124
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  • 89
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    Anomalous Diffraction Effects in the Sizing of solid particles in liquids (1991)
    Weinheim : Wiley-Blackwell
    Particle and Particle Systems Characterization 8 (1991), S. 175-178 
    Details
    ISSN: 0934-0866
    Keywords: Chemistry ; Industrial Chemistry and Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Process Engineering, Biotechnology, Nutrition Technology
    Notes: A study has been made of anomalous diffraction effects in the sizing of solid particles in liquids using a Malvern laser diffraction sizer. The particles were N.B.S. standard reference material 1004 glass spheres. The five liquids used were chosen to give a range of refractive index (R.I.) above and below that of the glass; the ratio of solid R.I. to liquid R.I. (m) ranged from 0.92 to 1.15. Measurements were made of the change in the light energy distribution pattern as the value of | m - 1 | was in creased or reduced towards zero. At high values of | m - 1 | the measured light energy distribution pattern was predicted adequately by the Fraunhofer diffraction approximation to Mie theory and the Fraunhofer computer software could be used to derive particle size distribution from the light energy pattern. For values of | m - 1 | near to zero, the Fraunhofer approach was in error but the anomalous diffraction approximation and software proved adequate for the back-calculation of size distribution from energy pattern.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/ppsc.19910080133
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  • 90
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    Masthead (1991)
    Weinheim : Wiley-Blackwell
    Chemical Engineering & Technology - CET 14 (1991) 
    Details
    ISSN: 0930-7516
    Keywords: Chemistry ; Industrial Chemistry and Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/ceat.270140101
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  • 91
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    An improved SRK-equation for the estimation of concentrations by inferential measurements (1991)
    Weinheim : Wiley-Blackwell
    Chemical Engineering & Technology - CET 14 (1991), S. 20-28 
    Details
    ISSN: 0930-7516
    Keywords: Chemistry ; Industrial Chemistry and Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: A method is proposed for solving the vapour-liquid equilibrium problem in binary distillation processes, when pressure and temperature are known. Special attention is paid to the applicability of the method for control purposes. Therefore, a comparison between measured and estimated concentrations is included for the case of propane-propylene distillation. The method is based on an improved Soave-Redlich-Kwong equation of state and is easy to implement on a process computer. It yields a close approximation of experimental vapour and liquid volumes. On applying the original SRK-equation at high pressures, an error in excess of 20% is obtained in the liquid volume which is one of the reasons why this equation cannot be used for control where high accuracy is required. In addition, the conventional mixing rule cannot reproduce the mole fractions correctly. Therefore, a new density-dependent mixing rule is put forward for modelling of experimental results.
    Additional Material: 12 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/ceat.270140104
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  • 92
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    Adsorption and desorption of halogenated hydrocarbons using activated carbon (1991)
    Weinheim : Wiley-Blackwell
    Chemical Engineering & Technology - CET 14 (1991), S. 59-64 
    Details
    ISSN: 0930-7516
    Keywords: Chemistry ; Industrial Chemistry and Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Environmental hazards caused by halogenated hydrocarbons and increasingly stringent regulations for limiting their emission require comprehensive investigations of these substances. The present work deals with the adsorption and desorption of halogenated hydrocarbons on activated carbon. The results could be useful in the utilization of landfill gases because halogenated hydrocarbons must be removed in order to avoid pollution and the loaded activated carbons have to be regenerated. Activated carbons are well suited to removal and recovery of halogenated hydrocarbons from gas flows.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/ceat.270140109
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  • 93
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    Electronic Resource
    Masthead (1991)
    Weinheim : Wiley-Blackwell
    Chemical Engineering & Technology - CET 14 (1991) 
    Details
    ISSN: 0930-7516
    Keywords: Chemistry ; Industrial Chemistry and Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/ceat.270140201
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  • 94
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    Studies of drop break-up in liquid-liquid systems in a rotating disc contactor. Part I: Conditions of no mass transfer (1991)
    Weinheim : Wiley-Blackwell
    Chemical Engineering & Technology - CET 14 (1991), S. 79-89 
    Details
    ISSN: 0930-7516
    Keywords: Chemistry ; Industrial Chemistry and Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Observations on the break-up of single drops in a rotating disc contactor show that there is a critical rotor speed below which drops of a given size do not break. Weber and Reynolds numbers are required to correlate the data and not simply a Weber number as for turbine agitated systems. The probability of break-up of a drop at the rotor edge is expressed in terms of a Weber number with a lower limit for critical conditions. The mean number of daughter drops produced on break-up is correlated as a simple function of drop diameter based on the critical diameter and agreement is found with data from other types of agitated equipment.
    Additional Material: 13 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/ceat.270140202
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  • 95
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    A new pneumatic bearing dynamometer for power input measurement in stirred tanks (1991)
    Weinheim : Wiley-Blackwell
    Chemical Engineering & Technology - CET 14 (1991), S. 105-108 
    Details
    ISSN: 0930-7516
    Keywords: Chemistry ; Industrial Chemistry and Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: A turntable dynamometer has been constructed for the accurate measurement of power input and mixing applications in bench stirred tank reactors. The main feature of this device is a pneumatic bearing with complementary conical parts. The conical pneumatic bearing permitted to apply eccentric loads without affecting its stability. The static friction torque in the pneumatic bearing was very small, 4 × 10-4 Nm, and can be neglected in the experimental ranges of measured torques, i.e. from 5 × 10-3 to 2.21 Nm. In accordance with the instrumentation used, the deviations obtained with the apparatus are less than 10% at low torque readings. At moderate torques, deviations lower than 1% are routinely obtained. Several power input measurements show that the obtained data scatter is lower than 2.5%. The power input response in the turbulent regime is in agreement with dimensional analysis: the power input depends on the cube of the impeller speed. In addition, data obtained with a turbine impeller under ungassed conditions agree with the predictions of a published correlation, which takes into account several geometrical parameters.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/ceat.270140206
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  • 96
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    A new process for indirect gas supply by means of perfluorinated polyethers (1991)
    Weinheim : Wiley-Blackwell
    Chemical Engineering & Technology - CET 14 (1991), S. 127-134 
    Details
    ISSN: 0930-7516
    Keywords: Chemistry ; Industrial Chemistry and Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: A new process has been developed for indirect gas supply for culturing shear sensitive cells by means of a perfluorinated hydrocarbon. Hostinert 216, a perfluorinated polyether, was used as oxygen and carbon dioxide carrier. Hydrodynamics and mass transfer, required for industrial implementation, were investigated in a drop column. Based on the knowledge, obtained with indirect gas supply, it has been possible to construct a waste-gas free sterile pilot plant. Correlations derived from performed measurements permit design of and scale-up to an industrial plant.
    Additional Material: 11 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/ceat.270140211
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  • 97
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    Electrochemical impedance spectroscopy of oxygen and hydrogen evolution on amorphous alloys in 1 M KOHDedicated to Professor Dr. Dr. hc. Dieter Behrens on the occasion of his 65th birthday (1991)
    Weinheim : Wiley-Blackwell
    Chemical Engineering & Technology - CET 14 (1991), S. 263-269 
    Details
    ISSN: 0930-7516
    Keywords: Chemistry ; Industrial Chemistry and Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: The mechanisms of oxygen and hydrogen evolution on amorphous alloys G 14 (Fe60Co20Si10B10) and G 16 (Co50Ni25Si15B10) in 1 M KOH at T = 298 K and 333 K were studied by electrochemical impedance spectroscopy (EIS). Comparative measurements were carried out on polycrystalline Pt electrodes. Impedance spectra in the frequency range 10-3 Hz ≤ f ≤ 104 Hz were analyzed to determine the kinetic behaviour of amorphous alloys by application of transfer function analysis, using non-linear fit routines. The EIS-data are interpreted in terms of consecutive reaction mechanisms for both oxygen and hydrogen evolution.
    Additional Material: 12 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/ceat.270140408
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  • 98
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    Masthead (1991)
    Weinheim : Wiley-Blackwell
    Chemical Engineering & Technology - CET 14 (1991) 
    Details
    ISSN: 0930-7516
    Keywords: Chemistry ; Industrial Chemistry and Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/ceat.270140501
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  • 99
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    Hydrodynamics, axial mixing and mass transfer in open turbine rotating disc contactor (OTRDC) (1991)
    Weinheim : Wiley-Blackwell
    Chemical Engineering & Technology - CET 14 (1991), S. 167-177 
    Details
    ISSN: 0930-7516
    Keywords: Chemistry ; Industrial Chemistry and Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: An experimental study of hydrodynamics, axial mixing and mass transfer has been carried out in a newly developed liquid-liquid extraction contactor, namely the open turbine rotating disc contactor (OTRDC). It has been established that the OTRDC can be operated with larger holdups of the dispersed phase, larger interfaces and, hence, more efficient mass transfer than the conventional RDC. In correlating axial mixing data, a combined model has been applied in which both the forward mixing due to drop size distribution and the backmixing of droplets are taken into account. The RTD curves of dispersed phase predicted by the model agree well with the experimental data. Comparison of experimental mass transfer data with those predicted by the proposed axial mixing model and the theoretical single drop model shows that they are in good agreement.
    Additional Material: 18 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/ceat.270140304
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  • 100
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    Two-phase flow and mass transfer in scrubbersPaper presented by B. Schmidt at the “Jahrestreffen der Verfahrens-Ingenieure”, Berlin, September 27 To 29, 1989. (1991)
    Weinheim : Wiley-Blackwell
    Chemical Engineering & Technology - CET 14 (1991), S. 162-166 
    Details
    ISSN: 0930-7516
    Keywords: Chemistry ; Industrial Chemistry and Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Experimental investigations were carried out in spray scrubbers of different sizes with cocurrent flow of gas and liquid. Of special interest were the local processes in the mass transfer zone. The scrubber was operated with warm water/air system (cooling tower) to obtain detailed information about mass transfer. Air is being humidified with water vapour, which in turn leads to a temperature drop in the liquid. The liquid temperatures are relatively easy to measure and are shown as liquid isotherms. In the case of plug flow, the liquid isotherms should be straight horizontal lines. In reality, significant deviations from plug flow are caused by the transfer of liquid to the walls. A large part of the liquid forms a film flow at the wall. Furthermore, nearly all the mass transfer is completed in the zone of liquid atomization immediately beneath the nozzle. The number of measured transfer units was between 0.5 and 2.0 and was significantly influenced by the liquid flow rate. Based on the improved knowledge of the proceses inside the scrubber, a simplified model has been developed. Since the model simulates all the essential processes inside the mass transfer zone, liquid distribution and mass transfer efficiency can be approximately predicted.
    Additional Material: 13 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/ceat.270140303
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