Mechanical properties of high-temperature alloy ZhS32 at 1150–1250°C

The mechanical properties of single crystals of alloy ZhS32 at a temperature of 1150–1250°C and deformation rates of 3 × 10⁻⁵, 10⁻⁴, and 10⁻³ sec⁻¹ are studied. The characteristics of true ductility in tests for long-term strength in a temperature range of 1150–1250°C are determined. __________ Translated from Metallovedenie i Termicheskaya Obrabotka Metallov, No. 1, pp. 38–40, January, 2006.     

Mechanochemical preparation of kaempferol intermolecular complexes for enhancing the solubility and bioavailability

Abstract

In this study, complexes of kaempferol (KF) with polysaccharide arabinogalactan (AG) and disodium glycyrrhizinate (Na₂GA) were prepared through mechanochemical technique to improve the solubility and bioavailability of KF. The physicochemical properties and the interactions of KF with AG/Na₂GA were investigated through dissolution, SEM, XRD, and DSC studies. The reduction of particle sizes and destruction of crystal forms revealed the formation of solid dispersion which may have assisted the dissolution of the drug. The accelerated stability study showed higher stability for KF–Na₂GA complex. In vivo pharmacokinetic study was performed to observe the plasma drug concentrations for KF complexes. Mechanochemical complexation of KF with AG/Na₂GA improved the pharmacological activity as evident by the inhibitory potential of the complexes towards carbohydrate metabolic enzymes. In vivo studies were performed in STZ-induced diabetic mice, where the group treated with KF–AG complex showed better liver and kidney function and lower blood glucose levels than pure KF. Therefore, mechanochemical complexes of KF with polysaccharide or glycyrrhizate may serve as a promising formulation for the treatment of diabetes.     

Manufacturing of patterned ZnO films with application for photoinitiated decolorization of malachite green in aqueous solutions

Patterned thin films, ZnO, are successfully prepared on glass substrates by the sol-gel method using dip-coating technique. The films, formed of ZnO nanocrystallites with hexagonal crystal structure, are characterized by means of scanning electron microscopy, Fourier transform infrared spectroscopy and X-ray diffraction. The as obtained ZnO films are studied with respect to photo-initiated bleaching of malachite green in aqueous solutions. The bleaching process is investigated at various initial concentrations of malachite green in the aqueous solutions by using ZnO films of different thicknesses. The obtained results are promising for the development of ZnO photocatalysts by the sol-gel method.     

Analysis of the quality of the output current of an autonomous inverter with a transformer with a pulsating magnetic field

Fourier series coefficients for an even and odd number of circular winding sections have been obtained by expanding in Fourier series step graphs that approximate the reference sine wave. These coefficients have been used to calculate the coefficients of harmonics of output voltage and current of an autonomous inverter with a circulating magnetic field transformer (CMFT) and construct their plots in the function of the number of CW sections and quality factors of resistive-inductive load.     

Characterization of CdTe nanocrystals during their synthesis in liquid paraffin: optical properties and particle growth

This article presents a systematic investigation of the optical properties and the growth process of CdTe nanocrystals during their hot-injection-based synthesis in liquid paraffin. Cadmium(II) stearate and tributylphosphine telluride are used as precursors. The as-obtained nanocrystals are characterized by transmission electron microscopy (TEM) with energy dispersive spectroscopy (EDS), X-ray powder diffraction (XRD), UV–vis absorbance, and fluorescence spectroscopy. The changes in optical absorbance and fluorescence during the nanocrystal synthesis are studied. The average nanocrystal size and the mean nanocrystal concentration are derived from the optical spectra and their changes during the synthesis are investigated. It is found that synthesis at lower temperature (150 °C) favors the continuous nucleation and leads to the formation of relatively smaller nanocrystals (~3 nm in size), whereas the nanocrystal concentration is relatively constant during synthesis at higher temperature (250 °C) thus leading to the formation of larger nanocrystals (~5 nm in size).     

A simple method of studying oxidation resistance of heparin-precipitated blood beta lipoproteins

Decrease of beta-lipoprotein resistance to copper-dependent oxidation is an important diagnostic criterion of risk of atherosclerosis. We developed a simple method for assessing resistance of heparin-precipitated beta-lipoproteins to oxidation induced by 50 microM copper ions. A strong positive correlation between the oxidation of precipitated and ultracentrifuged beta-lipoproteins in the presence of 50 and 10 microM copper ions, respectively, was revealed. In coronary patients oxidation resistance of precipitated beta-lipoproteins was decreased in comparison with that in healthy donors. The method is simple, informative, and easily available for clinical biochemical laboratories.     

Porous photocatalytically active ZnO films obtained from ethylcellulose modified solutions by spray pyrolysis

Nanocrystalline porous ZnO films are deposited onto alumina foil substrates by polymer-modified spray pyrolysis of zinc nitrate and zinc acetate solutions. The dependence of the concentration of added ethylcellulose and the type of zinc precursor on both the photocatalytic properties and films morphologies is investigated. It is established that the addition of ethylcellulose as a modifier in the spray solution leads to the formation of a porous structure with crystallites sizes about 15 nm, when zinc acetate is used as precursor. These films show better photocatalytic activity for degradation of Malachite Green (MG) dye than the films obtained from zinc nitrate modified solution. The zinc nitrate films exhibit weaker activity for degradation of MG regardless of their smaller crystallite size (8–12 nm). This can be explained with their lower porosity than that of polymer-modified zinc acetate films. It is established that 450 °C is the limit temperature of treatment for the preparation of ZnO films with good photocatalytic activities. This photocatalytic activity in films shows a drop in the comparison to the films treated at lower temperature, due to decreasing of the pore number and deterioration of the surface morphology.     

Measuring the loads on the spindles of Pilger-mill rolls

This article presents results from practical measurements of the torque on spindles in the drive of the work rolls of the Pilger mill in tube-production unit 8–16″. The measured values of torque are compared to rolling moments calculated on the basis of the principle of the mechanics of plastic media. __________ Translated from Metallurg, No. 6, pp. 47–49, June, 2007.