SHS of shape memory CuZnAl alloys

Aiming at preparation of shape memory alloys (SMAs), we explored the SHS of Cu_{1 − x} Zn_{1 − y} Al_{1 − z} alloys (0.29 < x < 0.30, 0.74 < y < 0.75, and 0.83 < z < 0.96). The most pronounced shape memory effect was exhibited by the alloys of the following compositions (wt %): (1) Cu(70.6)Zn(25.4)Al(4.0), (2) Cu(70.1)Zn(25.9)Al(4.0), and (3) Cu(69.9)Zn(26.1)Al(4.0). The effect of process parameters on the synthesis of CuZnAl alloys was studied by XRD, optical microscopy, and scanning electron microscopy (SEM). The grain size of CuZnAl was found to depend on the relative amount of the primary CuZn and AlZn phases. Changes in the transformation temperature and heat of transformation are discussed in terms of ignition intensity and compaction. Mechanism of the process depends on the level of the temperature attained relative to the melting point of components. At the melting point of AlZn, the process is controlled by the solid-state diffusion of AlZn into a product layer. The ignition temperature for this system depends on the temperature of the austenite-martensite transformation in CuZnAl alloys. The composition and structure of the products was found to markedly depend on process parameters. The SHS technique has been successfully used to prepare a variety of SMAs.      

To treat or not to treat: comparison of different criteria used to determine whether weight loss is to be recommended

Background  

Excess body fat is a major risk factor for disease primarily due to its endocrine activity. In recent years several criteria have been introduced to evaluate this factor. Nevertheless, treatment need is currently assessed only on the basis of an individual's Body Mass Index (BMI), calculated as body weight (in kg) divided by height in m². The aim of our study was to determine whether application of the BMI, compared to adiposity-based criteria, results in underestimation of the number of subjects needing lifestyle intervention.     

Choosing the technology of combined processing of titanium-rare-metal raw materials

The main rules and principles which govern the choice of new variants for chemical technology of combined processing of titanium-rare-metal raw materials are considered. The existing variants of the technology are characterized from the viewpoint of their technological, economical, and ecological efficiency and social importance for a given region. A realistic choice of a technology from a large number of available variants should take into account the entire combination of their advantages and disadvantages The implementation of a rational technological scheme will result in the creation of economically profitable and efficient domestic production satisfying the demands of Russian industry in rare-metal and titanium materials. Directions are noted in which it is expedient to continue studies on designing a rational technology of loparite concentrate or some other concentrate.     

The relationship between bioelectrical impedance phase angle and subjective global assessment in advanced colorectal cancer

Background  

Bioelectrical Impedance (BIA) derived phase angle is increasingly being used as an objective indicator of nutritional status in advanced cancer. Subjective Global Assessment (SGA) is a subjective method of nutritional status. The objective of this study was to investigate the association between BIA derived phase angle and SGA in advanced colorectal cancer.     

Highly heat-resistant mullite-silicon carbide materials

Cross-linking additions of silicon carbide and waste material from ferroalloy production make it possible to increase the heat-resistance index for mullite-containing refractories. For briquette specimens based on a charge containing aluminum powder it reaches 45 thermal cycles (1300°C – water). Translated from Novye Ogneupory, No. 11, pp. 44–46, November 2008.     

Rehabilitation of the radioactively contaminated objects and territory of the Russian Science Center Kurchatov Institute

This article is devoted to work done in 2002–2006 as part of the unified project Reabilitatsiya to rehabilitate radiation hazardous objects and sections of the radioactively contaminated territory of the Russian Science Center Kurchatov Institute. The main objects of the rehabilitation work were old storage sites built for radioactive wastes on the territory of the Institute when military and civilian nuclear technologies were under development. The structural features of the storage sites, including the volumes and characteristics of the wastes stored, are presented. The salient aspects of the disposal sites, taken into account during the rehabilitation work, are discussed. The organization of the rehabilitation operations and the sequence in which they are performed, the special features of the technical design solutions used, the technological methods, and ways for conducting the work are described. __________ Translated from Atomnaya énergiya, Vol. 102, No. 5, pp. 300–306, May, 2007.     

Synthesis and Characterizations of Triphenylamine End-Functionalized Polymers via Reversible Addition-Fragmentation Chain Transfer Polymerization

A novel reversible addition-fragmentation chain transfer (RAFT) reagent bearing triphenylamine (TPA) group, 4-diphenylamino-dithiobenzoic acid benzyl ester (DDABE), was designed and synthesized. It was used in the RAFT polymerizations of styrene (St) and methyl acrylate (MA) to prepare end-functionalized polymers. The results of the polymerization showed that the RAFT polymerizations could be well controlled using DDABE as the RAFT agent. Number-average molecular weight (M_n,GPC) increased linearly with monomer conversion, and molecular weight distributions were relatively narrow (PDI< 1.50). The results of chain-extension reaction, ¹H NMR spectra and UV/Vis spectra confirmed that most of the polymers chains were end-capped by the functional triphenylamine (TPA) groups. The effect of feed molar ratios of St/DDABE/AIBN on polymerization was investigated.     

Efficient allylation of cellulose in dimethyl sulfoxide/tetrabutylammonium fluoride trihydrate

The cellulose solvent dimethyl sulfoxide (DMSO)/tetrabutylammonium fluoride trihydrate (TBAF) was successfully applied as reaction medium for the synthesis of allyl cellulose by conversion of the polymer with allyl chloride in the presence of solid NaOH. Samples with degree of substitution from 0.50 to 2.98 were accessible by varying the molar ratio anhydroglucose unit:allyl chloride:NaOH and reaction time. DMSO/TBAF was found to be an efficient reaction medium for the preparation of highly functionalized samples from spruce sulfite pulp with degree of polymerization of about 500 even in a scale of 50 g. The allyl cellulose samples were characterized by means of FTIR- and NMR spectroscopy. Size exclusion chromatography revealed negligible polymer degradation during synthesis and purification of the samples.     

Molecular weight effect on the obtainment of parallel and perpendicular orientation in thermotropic poly(diethylene glycol <Emphasis Type="Italic">p,p′</Emphasis>-bibenzoate)

Summary The effect of molecular weight on the uniaxial orientation process has been analyzed in two samples of thermotropic poly(diethylene glycol p,p′-bibenzoate), evaluating the influence of that parameter on the type of orientation obtained. Several strain rates and deformation temperatures have been tested in order to map out the conditions for obtaining the two different kinds of orientation. The results show that in the lower molecular weight PDEB sample (M_w=31200) it is rather easy to get exclusively perpendicular “anomalous” orientation, with the molecular axes aligned transversely to the stretching direction. However, it is extremely difficult to obtain 100% parallel “normal” orientation. On the contrary, either type of orientation or a mixture of them can be easily developed for the higher molecular weight PDEB sample (M_w=102900).