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  • Hyperoxaluria
  • current efficiency
  • Cooper pairing
  • 1
    Digitale Medien
    Digitale Medien
    Springer
    Journal of applied electrochemistry 29 (1999), S. 1229-1235 
    ISSN: 1572-8838
    Schlagwort(e): additive ; antimony ; current efficiency ; power consumption ; zinc electrowinning
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie , Elektrotechnik, Elektronik, Nachrichtentechnik
    Notizen: Abstract The effects of the organic additives cetyltrimethylammonium bromide (CTABr) and tetrabutyl ammonium bromide (TBABr) on the electrowinning of zinc from acidic sulphate solutions were studied in the presence and absence of trace amounts of antimony(iii). The results indicated that CTABr has similar properties to the commonly used industrial additive glue with respect to current efficiency, power consumption, polarization behaviour, and the crystallographic orientation and surface morphology of the zinc deposits. TBABr was generally less useful with respect to all these properties. Voltammetric studies indicate that polarisation for zinc electrodeposition decreased in the order CTABr 〉 glue 〉 TBABr. The nature of the electrode reactions were investigated through measurements of exchange current densities, Tafel slopes and transfer coefficients.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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  • 2
    Digitale Medien
    Digitale Medien
    Springer
    Journal of applied electrochemistry 28 (1998), S. 915-920 
    ISSN: 1572-8838
    Schlagwort(e): Zinc electrowinning ; antimony ; triethylbenzylammonium chloride ; current efficiency ; polarization ; morphology ; power consumption
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie , Elektrotechnik, Elektronik, Nachrichtentechnik
    Notizen: Abstract The effects of triethylbenzylammonium chloride (TEBACl) on the electrowinning of zinc from acidic sulfate solutions have been studied in the presence and absence of antimony(iii). The factors considered included the current efficiency (CE), power consumption, polarisation behaviour, and the crystallographic orientations and surface morphology of the deposits. Compared with the traditional industrial additive, glue, the addition of TEBACl increased CE, reduced power consumption and improved the surface morphology. Maximum CE and minimum power consumption were obtained at 2mgdm−3 TEBACl and 0.01mgdm−3 Sb(iii). The exchange current density, Tafel slope and transfer coefficient were determined to elucidate the nature of the electrode reactions involved.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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  • 3
    Digitale Medien
    Digitale Medien
    Springer
    Urological research 14 (1986), S. 59-62 
    ISSN: 1434-0879
    Schlagwort(e): Stone formers ; Urolithiasis ; Stone inhibitors ; Hyperoxaluria ; Stone analysis
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary Fifty-two cases of urinary tract calculus disease were investigated for dietary habits, routine chemical and microscopic urinalysis, bacterial culture, quantitative analysis of 24 h urine sample and qualitative analysis of the stones. 54 out of the 56 stones analysed were of mixed type. Magnesium ammonium phosphate was present in 78.2% stones. Dietary habits revealed principal dependence on cereals, lack of animal proteins, consumption of oxalate rich vegetables and widespread consumption of tea. Urinary tract infection was present in 63.7% of the cases. Significant calcium oxalate crystalluria (2+ to 4+) was present in 34.6% of the cases. Hyperoxaluria, hypercalciuria associated with hyperoxaluria-lower excretion of magnesium and citric acid were important urinary risk factors in the local population. These observations strongly suggest the multifactorial etiology of stone disease in this region. Imbalanced nutrition and urinary tract infection were the principal risk factors for urolithiasis in this study.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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  • 4
    ISSN: 1434-0879
    Schlagwort(e): Hyperoxaluria ; Nephrolithiasis ; Diet ; Hypercalciuric ; Tribal population
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Abstract The nutrient intake of 69 stone formers (SFs) from three subsets of the local population (urban 22, rural tribal 22 and rural nontribal 25) and 69 age, sex, weight and socioeconomically matched control subjects (NSs) (urban 20, rural tribal 22 and rural nontribal 27) was studied. Simultaneously their timed 24-h urine samples collected over a similar period were analyzed. In general caloric and protein intake was low in all the groups but was strikingly low in the rural subjects. Intake of all nutrients was lowest in the tribal group. Although no difference was observed in diet between NSs and SFs in the same population subjects, SFs had higher urinary excretion of oxalic acid and calcium and lower excretion of citric acid and excreted more saturated urine. Notably magnesium intake was normal in both NSs and SFs, but mean excretion of magnesium was lower than normal in all the groups, suggesting its defective absorption. The influence of dietary intake of protein, carbohydrate, fat, fiber, calcium and oxalic acid on urinary excretion of calcium, oxalic acid, uric acid, inorganic phosphorus, magnesium and citric acid was examined using the chi-square test. No association was observed, thus suggesting that this low nutrient intake did not influence the lithogenic process. Thus, the overall observations suggest: (a) poor nutrition, (b) no effect of diet on urinary stone disease, (c) no difference in the nutrient intake between NSs and SFs and (d) a higher excretion of promoters and a lower excretion of inhibitors in SFs than in NSs.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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  • 5
    Digitale Medien
    Digitale Medien
    Springer
    Journal of superconductivity 12 (1999), S. 441-443 
    ISSN: 1572-9605
    Schlagwort(e): Cooper pairing ; biexciton
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Elektrotechnik, Elektronik, Nachrichtentechnik , Physik
    Notizen: Abstract In this paper, we have modified the Cooper theory by considering a biexcitonic attractive interaction for high T c superconductors. We have developed an expression for (2Δ/K B T c) as a function of phonon and biexciton mediated coupling constants. For the sake of simplicity, we use a two-square-well potential model (electron–phonon and electron–biexciton). The calculated values of (2Δ/K B T c) show good agreement with experimental values.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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