Measurement of young's modulus and hardness of Al-50 wt % Sn alloy phases using nanoindentation

The nanoindentation method was used to measure the Young's modulus and hardness of the phases of the alloy Al-50 wt % Sn: α-aluminum and eutectic. Samples are obtained in different ways, i.e., traditionally via the transition of the melt into a homogeneous structural state by heating to a certain temperature, followed by cooling using the cooling rate greater by the order than that of the traditional method and via the addition of 0.06 wt % Ti and 1 wt % Zr to the binary alloy. It has been found that the most significant effect of the Al-50 wt % Sn phases on the Young's modulus is the transition of the melt into a homogeneous structural state and the introduction of Zr into the melt. As part of the mathematical theory of elasticity, a numerical evaluation of the interfacial pressure that arises due to the difference between Young's modulus of α aluminum and eutectic has been performed. The calculation has showed that the extra pressure is nine times less for the alloy formed through the transition of the melt into a homogeneous structural state than for the alloy produced via a traditional way. © 2013 Pleiades Publishing, Ltd

ИССЛЕДОВАНИЕ ВЛИЯНИЯ СТРУКТУРНОГО СОСТОЯНИЯ РАСПЛАВА НА КРИСТАЛЛИЧЕСКОЕ СТРОЕНИЕ И МЕХАНИЧЕСКИЕ СВОЙСТВА ФАЗ СПЛАВА AL-50 МАС.%SN МЕТОДОМ НАНОИНДЕНТИРОВАНИЯ

Nanoindentation is used to measure Young's modulus, the hardness, the plasticity, and the yield strength of the phases in Al-50 wt % Sn alloy samples prepared by a traditional method and using liquid-state homogenization. The effect of an increase in the cooling rate by an order of magnitude and alloying with 0.06 wt % Ti or 1 wt % Zr on the mechanical properties of the phases in the Al-50 wt % Sn alloy is studied. The most substantial effect on Young's modulus of the phases in the Al-50 wt % Sn alloy is found to be exerted by the homogenization of the metallic liquid and the introduction of zirconium in the alloy melt: the metal forming of an ingot is improved substantially. © 2013 Pleiades Publishing, Ltd

THE INFLUENCE OF PHYSICAL METHODS OF VEGETABLES PROCESSING ON THE QUALITY OF FROZEN PRODUCTS

The indicators of quality and microbiological safety of frozen vegetable semi-finished products (for example, cut beet) processed in a microwave field for subsequent storage for 18 months at a temperature of minus 20±2 °C. Treatment with a microwave field was carried out under the following conditions: power 600 W and duration 5 min (180 kJ); power 1000 W and duration 4 min (240 kJ). It is established that treatment in the microwave field contributes to the preservation of consumer qualities of the product (total solids content, mass fraction of soluble solids, bound moisture content, microbiological effect) in the process of long-term low-temperature storage.The indicators of quality and microbiological safety of frozen vegetable semi-finished products (for example, cut beet) processed in a microwave field for subsequent storage for 18 months at a temperature of minus 20±2 °C. Treatment with a microwave field was carried out under the following conditions: power 600 W and duration 5 min (180 kJ); power 1000 W and duration 4 min (240 kJ). It is established that treatment in the microwave field contributes to the preservation of consumer qualities of the product (total solids content, mass fraction of soluble solids, bound moisture content, microbiological effect) in the process of long-term low-temperature storage

Maintenance of potato varieties in <i>in vitro</i> and field collections of the Russian Potato Research Centre

The main biological feature of potato varieties is vegetative reproduction. This mode of reproduction can be associated with problems due to the physiological ageing of the crop and the accumulation of specific pathogens causing reduced tuber yields. In order to avoid these problems, potato seed production widely uses modern biotechnological methods. The use of meristemic technologies allows preserving the identity of the biomaterial in the process of maintaining the potato collection in vitro, but even under these conditions there is a threat that modifications of individual economically valuable traits may get fixed. In potato varieties, such non-heritable deviations manifest themselves in the form of a shift in phenophases and the period of tubers ripening. The use of modern high-tech methods of varietal resources storage implemented on the basis of biotechnological approaches, makes it possible to maintain high quality of biomaterial. At the same time, mobility and practicality remain the main criteria for the effectiveness of different storage methods, depending on the extent to which they can be used in practice. In this review, the collection of varieties at Russian Potato Research Center is used as an example for considering the main stages of the formation and functioning of a modern Bank of Healthy Potato Varieties (BHPV), which supplies various regions of the Russian Federation with high-quality phytopathogen-free potato varieties

Buoyancy-driven flow inside an asymmetrically heated cavity

Buoyancy-driven flows inside enclosures are in the center of problems related to heat transfer because they can provide a significant insight into the physical mechanisms of heat transfer. Typical examples of such flows include Rayleigh–Bénard convection, differentially heated cavities and partially divided enclosures. In the present study, the buoyancy-driven flow inside an asymmetrically heated closed cavity is investigated and proposed as a benchmark case for future studies to assess the accuracy of simulations and to help in the validation of coarsened turbulence models. Additionally, from an application perspective such a configuration is highly relevant, e.g., in view of its similarity with passive solar systems such as ventilated building facades (Puangsombuta et al, J Fluid Mech 42(6):2218–2226, 2007, [1]) and Trombe walls (Zamora and Kaiser, Heat Mass Transf 45(11):1393–1407, 2009, [2]).</p

Hemodynamics monitoring in sport: Using hemodynamic monitor for sport training planning

The study stresses the meaning of the physiological measures that are obtained with the functional diagnostics devices and how these values can be used in coaching sportsmen. Methods: Hemodynamic monitor was used for monitoring hemodynamics and heart function of athletes (n=305) with different fitness levels. Active orthoclinostatic tests and antiorthostatic tests with passive body position changing were carried out with hemodynamics measurements recorded. Results: The most informative indicators and indices of heart function for high performance sport and their values at rest were detected. Along with common hemodynamics indicators (HR, SV, CO, EDV, blood pressure, etc.) the possibility of using correlation rhythmogram in coaching was studied. The correlation rhythmogram "cloud" dependence on athletes' fitness level was revealed in transient during active orthoclinostatic test

Complexation of thiacalix[4]arene methylphosphonic and sulphonic acids with amino acids

In this paper, host-guest complexation process of thiacalix[4]arene tetrakis-methylphosphonic and tetrakis-sulphonic acids with amino acids by HPLC and molecular modelling methods has been studied. It was shown that thiacalix[4]arene tetrakis-methylphosphonic acid due to transformability of macrocyclic skeleton and flexibility of methylphosphonic substituents can adopt its conformation for strong multicentre binding of the amino acids with association constant values 530-10,140 M-1 in water. © 2013 Taylor & Francis Group, LLC

Theoretical study about L-arginine complexes formation with thiotriazolin

Brain vascular diseases are one of the leading causes of morbidity, mortality and disability of population in the industrialized countries of the world. An important element of this problem’s solution is the creation of new highly effective and safe drugs, which would lead to mortality reduction, to increase in life expectancy and quality of life. Therefore it is interesting to create a new combined drug based on L-arginine and thiotriazolin. Purpose of the study: to consider the possible structure and energy characteristics of complexes formed by L-arginine, 3-methyl-1,2,4-triazolyl-5-thioacetate (MTTA) and morpholine. Calculation method. The initial approximation to the complex geometry was obtained using molecular docking with the help of AutoDock Vina program. The obtained ternary complexes were pre-optimized by semi-empirical PM7 method with modeling the impact of the environment by COSMO method. The calculations were carried out using MOPAC2012 program. Then they were optimized by B97-D3/SVP + COSMO (Water) dispersion-corrected DFT-D with geometrical spreading correction on insufficiency of gCP basis set. A more accurate calculation of the solvation energy was conducted by SMD. The calculations by density functional method were carried out using the ORCA 3.0.3 software. Energy complex formation in solution was calculated as the difference of the Gibbs free energy of the solvated complex and its individual components. Results. Quantum chemical calculations show, that thiotriazolin and L-arginine are able to form ternary complexes, where molecules are linked by multiple hydrogen bonds. The calculation data suggest, that studied complexes are thermodynamically unstable in solution. The energies of them are positive, but rather low despite charge gain of a number of intermolecular hydrogen bonds. Finding. Based on the results of the conducted quantum-chemical study of a three components system (MTTA, morpholine, and L-arginine) it is possible to show the possibility to form ternary complexes with low stability in infinite dilute solutions. It should be noted that two negative charges are always localized in formed complexes on the deprotonated carboxyl groups. The positive charges are located either on the guanidine moiety and the a-amino group of L-arginine, or on the guanidine moiety of L-arginine and protonated molecule of morpholine. It can be expected that the strengthening of intermolecular interactions in the real solutions may result in increased stability of the complexes

Bis(N-{bis­[meth­yl(phen­yl)amino]phos­phor­yl}-2,2,2-trichloro­acetamide)di­nitrato­dioxidouranium(VI)

In the title compound, [UO2 L 2(NO3)2] {L = N-{bis­[meth­yl(phen­yl)amino]phosphor­yl}-2,2,2-trichloro­acetamide, C16H17Cl3N3O2P}, the UVI ions are eight-coordinated by axial oxido ligands and six equatorial O atoms from the phosphoryl and nitrate groups in a distorted hexa­gonal–bipyramidal geometry. There are disordered fragments in the two coordinating L ligands: the trichloro­methyl group is rotationally disordered between two orientations [occupancy ratio 0.567 (15):0.433 (15)] in one ligand, and a meth­yl(phen­yl)amine fragment is disordered over two conformations [occupancy ratio 0.60 (4):0.40 (4)] in the other ligand. In the crystal structure, intra­molecular N—H⋯O hydrogen bonds between the amine and nitrate groups are observed