Rheological characterization of yellow grease and poultry fat

The rheological properties of yellow grease and poultry fat and their liquid density at 25.0°C were experimentally determined. Dynamic viscosities of these industrial recycled fat products were measured for shear rates of 0.65 to 32.34 s⁻¹ at temperatures of 15.6 to 71.1°C. The resulting measurements were fitted to a power law model to obtain values for the consistency coefficient and the flow behavior index. The data was also fit to Andrade's equation to relate viscosity to temperature. These results indicated pseudoplastic flow behavior for both products, with increasing non-Newtonian behavior at higher temperatures and shear rates.     

Transfer characteristics of multicomponent cooling agents

A method for calculating and predicting the coefficients of thermal conductivity and viscosity of pure substances and two- or multicomponent mixtures has been developed on the basis of the single-parameter law of the corresponding states.Translated from Inzhenerno-Fizicheskii Zhurnal, Vol. 55, No. 4, pp. 620–624, October, 1988.     

Efficacy of low-dose dopamine in preventing amphotericin B nephrotoxicity in bone marrow transplant patients and leukemia patients

This study evaluated the efficacy of low-dose dopamine for prevention of amphotericin B-induced nephrotoxicity in autologous bone marrow transplant and leukemia patients. Seventy-one patients undergoing cytoreductive therapy who required amphotericin B were randomly assigned in an unblinded fashion to a group receiving continuous-infusion low-dose dopamine (3 microgram/kg/min) or a group receiving no dopamine. Amphotericin B was dosed at 0.5 or 1.0 mg/kg/day based on computerized tomography scan results or presence of positive blood cultures. No patient received saline boluses. The rate of nephrotoxicity, severity as graded by Southwest Oncology Group toxicity criteria, and time to each grade of nephrotoxicity were compared between the two groups. Eighty percent of the no-dopamine group and 66.7% of the dopamine group developed nephrotoxicity, defined as a 1.5-fold or greater increase in baseline serum creatinine level (P = 0.20). No statistical difference was noted at any grade of nephrotoxicity between the two groups. Thirty-four percent of patients in the no-dopamine group versus 17.6% in the dopamine group had a 2.5-fold or greater increase in serum creatinine level, which was not statistically significant (P = 0.0888). Ten patients developed grade IV nephrotoxicity and were withdrawn from the study, 7 in the no-dopamine group and 3 in the dopamine group (P = 0.19). The time to each grade of nephrotoxicity was also not significantly different for the two groups. Eleven adverse drug reactions were reported in the dopamine group in comparison to one in the no-dopamine group. Thus, dopamine offers little in the way of prevention of nephrotoxicity associated with amphotericin B therapy. Although the significance of drug reactions in the dopamine group is not clearly established due to lack of cardiac monitoring in the no-dopamine group, dopamine therapy is not without complications.     

Molecular weight distribution in cellulose triacetates and its effect on the mechanical properties of fibres

Conclusions 1. A precise method is defined for determination of the molecular-weight distribution of the original cellulose acetate by fractional precipitation of 1% methylene chloride solutions of the TAC in ethanol.2. A method is developed for quantitative determination of low-molecular fractions which is based on extraction of the polymer from a mixture of methylene chloride and ethanol at 25°C with addition of ammonium thiocyanate.3. The dependence of the physical and mechanical properties of triacetate fibres on the average molecular weight of the polymer is demonstrated.Tashkent Institute for Textiles and Light Industry; HIIKhTTs MKhP SSSR, Tashkent; Kaunas Factory. Translated from Khimicheskie Volokna, No. 5, pp. 48–50, September–October, 1969.     

Investigations of Ultrasound Propagation in Porous Impurity-Helium Solids

The velocity and attenuation of ultrasound passing through porous impurity-helium solids immersed in liquid ⁴He have been measured in the temperature range 1.1–2.3 K. These solids were formed by injecting a mixture of impurity (e.g. D₂, Ne, N₂ or Kr) and helium gases into superfluid ⁴He. The sound signal seemed to propagate mainly in the helium contained in the pores, rather than through the solid sample itself. We found that the speed of sound at low temperatures is close to and decreases more rapidly with temperature than first sound in bulk helium, similar to behavior observed in aerogel. The attenuation of sound in helium in the compressed impurity-helium solids is bigger than in bulk helium and increases rapidly with temperature up to 1.65 K, after which a crossover to a much weaker temperature dependence was observed.