Thermal properties of sodium-sulphur cells

The heat capacity and the rate of heat generation of Na/S cells during discharge and charge were determined. The measurements were carried out in a furnace with very low heat loss and low heat capacity (quasi-adiabatic arrangement). A linear relationship between (1/I)(dT/dt) andI, whereI is the discharge or charge current and dT/dt the temperature gradient, was obtained. From these plots the heat capacity of the cell and the entropy term could be determined. It turned out that, due to a steep entropy increase beyond about 80% state of discharge, the heat generation rate increased strongly in this region. During charging, this effect causes a cooling effect at low currents. The data presented here are important for the design of the thermal management system of an electric vehicle battery.     

Shedding of tumour necrosis factor receptors from purified villous term trophoblasts and cytotrophoblastic BeWo cells

Within the placenta tumour necrosis factor-alpha (TNF-alpha) and its surface receptors TNF-RI and -RII have been detected on villous cyto- and syncytiotrophoblast and a role in trophoblast function/differentiation and turnover has been suggested. Here, we show for the first time that purified villous trophoblasts and cytotrophoblastic BeWo cells extensively shed TNF receptors, suggesting that release of these soluble proteins is an inherent property of trophoblasts. In supernatants of purified villous trophoblasts, TNF-RI and -RII increased from undetectable levels to 307 pg/ml and 484 pg/ml, respectively, within 12 h of cultivation. In BeWo cells, 26 pg/10(5) cells and 54 pg/10(5) cells of soluble TNF-RI and -RII, respectively, accumulated within 24 h of culturing. While forskolin did not alter TNF-RI expression, TNF-RII mRNA, protein and secretion were selectively up-regulated in these choriocarcinoma cells suggesting that elevation of cAMP levels could modulate cellular events by TNF-RII-mediated signal transduction. Interleukin-1, which greatly enhances TNF-alpha release from trophoblast cells, did not alter shedding of both receptors from villous trophoblasts or BeWo cells. Secretion of TNF receptors from the trophoblast may explain the high levels of soluble TNF-binding proteins in urine of pregnant women and could play a role in regulating TNF-alpha activity in the placental villus or protection against the cytotoxic effects of the cytokine.     

Influencing of the thyroid hormone system by long-term treatment with 5-5 diphenylhydantion in children and adolescens (author''s transl)]

In two normal nasal septa, fine-dissected and stained by PAS-alcian blue whole-mount methods, counts of goblet cells were done in eight different localities in 1, 2, 5, 10, 20, 30, 50, and 100 fields measuring 0.01768 mm2. The median density and range of goblet cells by each mode of counting were compared and the mean deviation determined. Even as little as 2-5 blindly placed counts, which do not take much time, afford in a 4 mm2 area a fairly reliable orientation regarding density, considerably more reliable than an estimate of the density in sections, so often reported in the literature. Determination of the goblet cell density can be included as a routine method in the histopathological diagnosis of mucosal diseases of the upper and lower respiratory tract.     

Berechnung des Kriechverhaltens druckbeanspruchter dickwandiger Kugelbehälter aus anisotropem Material

Zusammenfassung Das station?re Kriechverhalten von dickwandigen, mit innerem überdruck beaufschlagten kugelf?rmigen Beh?ltern wird unter Berücksichtigung der „tensoriellen Nichtlinearit?t” der Materialgleichungen untersucht. Unter Verwendung der Theorie endlicher Verzerrungen werden die Untersuchungen für isotrope wie auch für anisotrope, inkompressible Werkstoffe durchgeführt. Es wird dabei die Annahme getroffen, da? mittels einer Regelung der innere Druck w?hrend des Kriechvorgangs konstant gehalten wird. Die Untersuchung wurde von der Deutschen Forschungsgemeinschaft (DFG) finanziell unterstützt, wofür an dieser Stelle gedankt sei.     

Die kinetik der zinkelektrode in wässrigen malonatlösungen

The kinetics of dissolution and deposition of zinc in sodium malonate solutions containing NaClO₄ as the base electrolyte was investigated. The steady state polarization curves and the frequency dependence of the faradaic impedance indicate a consecutive charge-transfer reaction with adsorbed monovalent zinc as the intermediate. The dependence of the polarization curves and of the faradaic impedances on the concentrations of malonate and zinc salt are explained by the following mechanism: During the anodic transfer reaction of zinc yielding monovalent zinc a complex with one malonate ion is formed. The subsequent oxidation to divalent zinc can follow two parallel paths of comparable rates. The charge-transfer reaction may directly yield a zinc complex with two malonate ions, or, a complex with one malonate ion may participate in the charge-transfer, the complex with two malonate ions being the product of a homogeneous reaction in solution.     

Trends in Thermal Separation Technologies – An Industrial Perspective

The article discusses future trends and their implications on separation technologies starting from the main drivers of technological developments. Especially the consequences of the expected energy and raw material change and the increasing international economic competition on process technologies are addressed. Special attention is given to the opportunities of increasing computational power and the availability of high-performance networks for scientific modeling and their use in process industries.     

Hydrocarbon deposits formed during n-butane isomerization on sulfated zirconia

The hydrocarbon deposits formed during n-butane isomerization on sulfated zirconia are spectroscopically characterized by infrared, in situ Raman and in situ UV-VIS spectroscopy. Evidence is summarized that suggests the formation of alkenyl and cycloalkenyl ions which presumably are precursors for aromatics that lead to catalyst deactivation. This revised version was published online in June 2006 with corrections to the Cover Date.     

FTIR spectroscopic evidence of formation of geminal dinitrogen species during the low-temperature N2 adsorption on NaY zeolites

Adsorption of N₂ on NaY zeolites at 85 K and equilibrium pressures higher than 1 kPa results in the formation of geminal dinitrogen complexes characterized by an IR band at 2333.5 cm⁻¹ (2255.4 cm⁻¹ after adsorption of ¹⁵N₂). With decreasing equilibrium pressure the complexes tend to loose one N₂ ligand, thus forming linear species characterized by an IR band at 2336.8 cm⁻¹ (2258.7 cm⁻¹ after adsorption of ¹⁵N₂). All species disappear completely after evacuation. Co-adsorption of N₂ and CO revealed that the dinitrogen complexes are formed on Na⁺ cations. The changes in the concentrations of the linear and geminal N₂ species with the changes in the equilibrium pressure are excellently described by equations of adsorption isotherms proposed earlier for mono- and di-carbonyls. This revised version was published online in July 2006 with corrections to the Cover Date.