Library

feed icon rss

Your email was sent successfully. Check your inbox.

An error occurred while sending the email. Please try again.

Proceed reservation?

Export
  • 1
    Electronic Resource
    Electronic Resource
    Springer
    Oxidation of metals 32 (1989), S. 337-355 
    ISSN: 1573-4889
    Keywords: Fe-Cr-Al ; aluminum oxide ; adherence ; sulfur ; reactive elements
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: Abstract A recent theory, explaining the effect of reactive elements on oxide adherence, states that sulfur adversely affects adherence and that reactive elements improve adherence by tying up sulfur as refractory sulfides. This theory is supported by work presented here, which correlates adherence behavior of Fe-Cr-Al alloys containing group IIIB through VIB elements with the stability of the sulfides that these elements form. Results show that poor adherence is produced by elements that form sulfides less stable than Al2S3 (VB and VIB elements), while good adherence is produced by elements which form sulfides more stable than Al2S3 (IIIB and IVB elements). In addition, the relative stability of sulfides, oxides, nitrides, and carbides must be considered. For example, group-IIIB elements are effective at much lower concentrations than group-IVB elements, because they react preferentially with S while group IVB elements react with C, N, and O before S.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 2
    Electronic Resource
    Electronic Resource
    Springer
    Oxidation of metals 29 (1988), S. 23-43 
    ISSN: 1573-4889
    Keywords: Fe-Cr-Al ; aluminum oxide ; adherence ; sulfur
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: Abstract Recently a new theory was proposed to explain the effect that reactive elements have on oxide adherence. Based on data obtained on Ni-Cr-Al-Y material, this theory stated that trace quantities of sulfur in the alloy degrade adherence by weakening the metal-Al2O3 bond. The work presented here extends this concept to Fe-Cr-Al alloys by examining Al2O3 adherence on foil samples with various bulk sulfur levels obtained using high-temperature vacuum anneals. Results show that long-time vacuum anneals dramatically increase the adherence of the subsequently grown aluminum oxide, concurrent with removal of sulfur from the matrix. This evidence shows that the Al2O3-metal bond is intrinsically strong without the presence of reactive elements such as Y or rare earths in the alloy. Sulfur in the alloy, and not void formation, was found responsible for oxide spalling. In addition, voids were eliminated by reducing the sulfur concentration near the oxide-metal interface.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 3
    Electronic Resource
    Electronic Resource
    Springer
    Oxidation of metals 36 (1991), S. 57-80 
    ISSN: 1573-4889
    Keywords: Fe-Cr-Al ; oxidation ; aluminum oxide ; air ; exhaust gas
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: Abstract Fe-20Cr-5Al alloy foils are used in automotive catalytic converters. This work examines oxidation behavior of four production-processed alloy foils in both air and synthetic exhaust gas environments. Oxidation tests were performed between 750° C and 1150° C for times to 96 hrs. Weight gain results in both atmospheres were similar, an indication that the same mechanism controls oxidation in both environments. At high temperatures (〉-950° C) both atmospheres produce weight gains consistent with α-alumina growth. Activation energies of 323 kJ/gmole and 271 kJ/gmole were calculated for oxidation in air and synthetic exhaust gas, respectively. At lower temperatures (〈-850° C), accelerated weight gains can occur from growth of transition alumina. Despite similar weight gain results, the two atmospheres produce different oxide morphologies: at 950° C and above, air produces a rounded, porous oxide while synthetic exhaust produces a more compact, angular oxide. Unexpectedly, oxide spalling occurred on foils oxidized in synthetic exhaust at 1050° C and above.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 4
    ISSN: 1573-4889
    Keywords: Fe-Cr-Al ; oxidation ; air ; exhaust gas ; aluminum oxide ; oxide adherence ; reactive elements
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: Abstract This work evaluated the adherence of oxide grown in air and synthetic exhaust gas on Fe-20Cr-5Al alloys containing strong sulfide-forming elements: Ca, Mg, Y, Ce, La, Ti, and Zr. Results support the theory that reactive elements provide good oxide adherence on alumina-forming materials primarily by tying up sulfur as stable Sulfides; however, other influences on adherence were found. Highly volatile elements, such as Ca and Mg, lose their sulfur-controlling ability by diffusing out of the matrix and into the growing oxide scale. Zirconium results in the growth of an extensive network of oxide pegs into the substrate which improves adherence. Titanium segregates to the alumina scale and acts as a sink for S in the matrix. In synthetic exhaust gas (N2+CO2+H2O), local oxide spalling was observed and was shown to be caused by H2O in the atmosphere. The added benefits of Ti and Zr, i.e., forming oxide pegs and sinks for S, improve adherence in this environment.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 5
    Electronic Resource
    Electronic Resource
    Springer
    Oxidation of metals 40 (1993), S. 295-320 
    ISSN: 1573-4889
    Keywords: Al-coating ; aluminum oxide ; Fe-Cr alloy ; oxidation resistance ; rare earths ; yttrium
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: Abstract Aluminum-coated Fe-20Cr-(rare earth or yttrium) alloy foils were developed with oxidation resistance equivalent or superior to Fe-20Cr-5Al-(rare earth or yttrium) alloy foils. The coated foils were made by dipping Fe-20Cr sheet into a salt-covered aluminum bath and then rolling the sheet to foil. Oxidation resistance of the coated foil was enhanced by adding rare earths or yttrium to the Fe-20Cr substrate alloys to insure oxide adherence. Test results indicate that only sufficient addition to tie up sulfur as a stable sulfide is needed in the Fe-20Cr alloy. Aluminum-coated foils show lower oxide growth rates than similar Fe-Cr-Al alloys, most likely the result of fewer impurities (particularly Fe) is the coated foils' growing oxide scale.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 6
    ISSN: 1573-8744
    Keywords: procainamide ; pharmacokinetics ; constant-rate infusion ; acetylator phenotype ; pharmacogenetics ; renal impairment
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract The pharmacokinetics of procainamide was determined in 21 lidocaine-resistant patients who received the drug according to a pharmacokinetically designed double-infusion technique. Thirteen patients were phenotyped as slow acetylators, seven as fast, and one as intermediate. The total body clearances (ClT) of PA in slow and fast acetylators were 22.6 and 34.8 liters/hr, respectively. The fraction of PA cleared by the formation of NAPA in the corresponding acetylator group was 0.2 and 0.4. Renal impairment affected the pharmacokinetics of PA more profoundly as the ClTs of PA in patients with and without renal impairment were 17.9 and 31.2 liters/hr, respectively. None of the calculated volumes of distribution was affected by acetylator phenotype or renal impairment. These data identify the contribution of at least two of the major factors accounting for variability in PA disposition in patients undergoing therapy.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 7
    ISSN: 1573-8744
    Keywords: etoposide ; etoposide phosphate ; bioequivalence ; pharmacokinetics ; pharmacodynamics ; humans ; cancer
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract The bioequivalence of etoposide phosphate, a prodrug of etoposide, to etoposide was assessed in a randomized, crossover study in 29 patients with histologically established solid tumors that had failed conventional treatment. Cohorts of patients received one treatment course each of etoposide and etoposide phosphate which consisted of a 100 mg/m2 per day etoposide equivalent dose infused iv over 1 hr on a Day 1 to 5 schedule of treatment. The second course was administered 21 days later or on recovery of blood cell counts. Plasma and urine samples were collected over 24 hr on Day 1 of each course and assayed for etoposide content by a validated HPLC/UV method. Resulting data were subjected to noncompartmental pharmacokinetic analysis. Hematology profiles were obtained by collecting blood samples prior to the first course and twice a week after each course. The pharmacodynamics and pharmacokinetics of etoposide were virtually identical after the two treatments. The point estimates (90% confidence intervals) for nadir WBC, granulocytes, hemoglobin, and platelets expressed as % decrease from the baseline, and for the pharmacokinetic parameters, Cmax, and AUC0-∞, after intravenous etoposide phosphate relative to etoposide were 100% (96%, 105%), 97% (91%, 103%), 95% (82%, 109%), 95% (84%, 106%), 107% (101%, 113%), and 113% (107%, 119%), respectively. Therefore, etoposide phosphate is bioequivalent to etoposide based on pharmacokinetic and pharmacodynamic assessments.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 8
    ISSN: 1573-904X
    Keywords: SK&F 107647 ; peptide ; pharmacokinetics ; hematore gulatory ; adenocarcinoma ; cytokines
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract Purpose. To describe the pharmacokinetics of SK&F 107647, a synthetichematoregulatory peptide, in healthy volunteers and in patientswith adenocarcinoma.Methods. SK&F 107647 pharmacokinetics were evaluated in 2dose-escalation studies. Volunteers received SK&F 107647 as single15-minute iv infusion doses of 1, 10, 100, 500, and 1000 μg/kg. Cancerpatients received 2-hour iv infusions of 0.001, 0.01, 0.1 and 1μg/kg once daily for 10 days. Drug concentrations were quantified in plasmaand urine of healthy volunteers and on days 1 and 10 in plasma ofcancer patients receiving the two top dose levels.Results. In volunteers, mean clearance (CL) ranged from 76.7 to 101ml/hour/kg; mean volume of distribution at steady-state (Vss)rangedfrom 175 to 268 ml/kg. Most of the administered dose was renallyexcreted as intact peptide within 24 hours postinfusion. In patients,mean CL was 57.6 ml/hour/kg, mean Vss ranged from 128 to 150ml/kg and terminal half-life from 2.1 to 3.4 hours. There was littleaccumulation of drug. In both studies, linear pharmacokinetics wasobserved. Clearance approached normal glomerular filtration rate(GFR) in volunteers and correlated with creatinine clearance incancer patients.Conclusions. SK&F 107647 exhibits linear pharmacokinetics, a smallVss, and clearance, primarily renal, approaching normal GFR.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 9
    ISSN: 1573-904X
    Keywords: allometric scaling ; peptide ; pharmacokinetics ; hematology ; infection
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract Purpose. To study the pharmacokinetics of SK&F 107647, a novel hematoregulatory agent, in rats, dogs, and patients with non-lymphoid solid tumor malignancy. Methods. Sprague Dawley rats and beagle dogs (n = 6 each; 3 M, 3 F) were given 25 mg/kg of SK&F 107467 as an iv bolus injection, and patients (n = 6; 4 M, 2 F) received 100 ng/kg as a 2 hour iv infusion. Plasma samples were assayed for drug using either HPLC (rat and dog) or RIA (human). Results. In each species the plasma clearance (CL) of SK&F 107647 was low in relation to hepatic blood flow, and the volume of distribution (Vdss) was reflective of distribution to extracellular body water. The plasma CL in humans was near that of average glomerular filtration rate. Using allometric equations for interspecies scaling (Y = a·Wb), body-weight normalized human pharmacokinetic data were reasonably predicted using either the body weight normalized rat or the dog data. The allometric exponents (b) for CL, Vdss, and T1/2 of SK&F 107647 were 0.63, 0.94, and 0.29, respectively. Conclusions. Use of a limited pool of available animal data allowed for reasonable predictions of human pharmacokinetics of SK&F 107647.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 10
    Electronic Resource
    Electronic Resource
    New York : Wiley-Blackwell
    Biopolymers 20 (1981), S. 803-816 
    ISSN: 0006-3525
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Proton and phosphorus nmr have been used to investigate the double-helical structures of polyriboadenylic acid [poly(A)] formed in acidic solutions (pH 〈 6). The results obtained at low pH (∼4.5) are consistent with the model for the acid poly(A) double helix proposed by Rich [Rich, A., Davies, D. R., Crick, F. H. C. & Watson, J. D. (1961) J. Mol. Biol. 3, 71-86]. Other models that have been proposed are inconsistent with the nmr data. The nmr measurements have also been used to examine the conformation of poly(A) helix in the half-protonated state. Although the base-stacking arrangement of this state is similar to that observed in the more extensively protonated low-pH state, the phosphate backbone conformation is different from that found in either the neutral or low-pH structures.
    Additional Material: 8 Ill.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
Close ⊗
This website uses cookies and the analysis tool Matomo. More information can be found here...