Search

Abstract—The results of comprehensive studies of the properties of imported syringe gland materials are presented. The studied materials were identified and their domestic analogs were found. [ABSTRACT FROM AUTHOR]

The work deals with the study of secondary-phase precipitation in binary and ternary zirconium-based alloys with extra-small content of doping within the framework of the phase-field approach. Developed phase-field model is applied to study β-phase precipitation in the model system of commercial Zr-Nb-Sn and Zr-Nb alloys at thermal treatment. An analysis of local rearrangement of doping and equilibrium vacancies during precipitation is provided. Kinetics of precipitation, size and distribution of the precipitates, concentration of the species in precipitates and matrix are studied. Mechanical response including the plastic deformations in precipitated solid is discussed. As shown, the yield-strength change increases during precipitation. Yield and ultimate strength are studied at different shear rates for the annealed alloy. Formation and growth of slip planes and dislocation loop-precipitate interaction governed by elastic-moduli difference is analysed. As shown, the emergence of dislocation loops around precipitates follows the Orowan's mechanism. Modelling the radiation-induced precipitation during neutron irradiation of zirconium alloys with low content of doping is performed within the framework of the developed phase-field model by taking into account ballistic mixing and the dynamics of point defects with their sinks. As shown, in a sample initially containing precipitates of the secondary phase, irradiation results in the dissolution of precipitates at small doses and reprecipitation with dose accumulation. Analysis of precipitation dynamics and statistical distributions of precipitates with local rearrangement of non-equilibrium vacancies around precipitates at neutron irradiation is provided. As shown, the competition between the ballistic mixing and the thermodynamic force plays a major role in kinetics of radiation-induced precipitation and precipitates' dissolution. The estimation of mechanical properties of Zr-Nb alloy during irradiation under reactor conditions is provided. [ABSTRACT FROM AUTHOR]

The aim of the paper is to study the possibilities of providing the local consumer with electricity from renewable sources to reduce dependence on centralized supply. The peculiarity of the task is the random influence of renewable energy and consumption on ensuring the energy balance in the local power system, by choosing the composition and capacities of renewable generation and auxiliary equipment. A storage battery and a conventional fuel generator are considered as auxiliary balancing equipment. A simulation model was applied, which allows taking into account the peculiarities of this system and the nonguaranteed nature of the power of solar or wind plants. The components of the power balance are described as the decomposition of a certain random process, which is a feature of this model. The volume of needs for energy flows between local and centralized energy systems, their variability with different parameters of accumulation and auxiliary generator is calculated. The combination of wind and solar energy makes it possible to reduce dependence on the general electricity grid. The same result is provided by the use of intermediate energy accumulators and an auxiliary source such as a diesel generator. A comparison of the energy balancing indicates the different role of wind and solar energy at different times of the year: the use of installed capacity and the level of energy consumption can vary significantly. Other influencing factors are the speed of battery charging and energy loss during conversion - the consequence is the need for different duration of operation of the auxiliary generator and frequency of its activation. The reliability of the simulated results is verified by comparing them with real examples, the differences are at the level of 5-10 %. The proposed model allows us to choose the configuration of generating and auxiliary equipment with a known mode of electricity consumption, and to evaluate the possibilities of ensuring the energy balance. Bible 23, fig. 3, tab. 9. [ABSTRACT FROM AUTHOR]

We extend reaction rate theory to study dislocation loops growth and associated radiation growth in binary Zr-Sn alloys under neutron irradiation at reactor conditions. A model to describe experimental data for loops' number density is proposed. We discuss dose dependences of dislocation loop radii, their densities and growth strains and analyse an influence of irradiation temperature and sinks' strengths on statistical properties of loops. A competition between the interstitial and vacancy -type loops is studied. Local loops distribution inside grains is analysed. Estimation of hardening of material is provided. Obtained results are compared with experimental observations. [ABSTRACT FROM AUTHOR]

Copyright of Scientific Bulletin of National Mining University is the property of National Mining University, State Higher Educational Institution and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Scientific Bulletin of National Mining University is the property of National Mining University, State Higher Educational Institution and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Different types of luminescence (photoluminescence, cathodoluminescence, X-ray luminescence in the range from 360 to 900 nm of monocrystalline diamond powders with grains from 125/100 to 250/200 µm) were studied. The powders were divided into different groups according to the perfection degree of their crystal structure and magnetic susceptibility value. At the room temperature the H3 luminescence of a diamond defect prevailed in all groups of crystals. At the liquid nitrogen temperature in the spectra of cathodoluminescence nickel centers dominated. Using selected diamonds and Sylgard 184 polysiloxane elastomer the samples of composite scintillators were made and their radiation resistance investigated. The higher radiation resistance relative of the standard YSO:Ce scintillators to the irradiation with fast electrons was installed. [ABSTRACT FROM AUTHOR]

Copyright of Electronics & Control Systems is the property of National Aviation University and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Scientific Bulletin of National Mining University is the property of National Mining University, State Higher Educational Institution and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The article is dedicated to the matters of historical memory preservation at the individual and collective levels. The rituals of Soviet people, the creation of myths about the Great October Revolution and the Great Patriotic War have been analyzed. It has been scientifically proved that contemporary commemorative initiatives do not take into account the specifics of memorable stereotypes about the Second World War, but stir up conflict zones in society, which are skillfully used by external forces to destabilize the situation in Ukraine. [ABSTRACT FROM AUTHOR]

Lagrange problem with the account of functional limitation at any functional limitations at any moment in a given interval is presented. The required conditions for optimal trajectories of the determinated dynamic system synthesized as space vehicle trajectories have been obtained. [ABSTRACT FROM AUTHOR]

An improved algorithm of median flow used for visual object tracking is described. The improvement consists in adaptive selection of aperture window size and number of pyramid levels at optical flow estimation. It can increase the tracking efficiency as compared to the basic algorithm, especially when dealing with small and low-contrast objects. The proposed version of the algorithm has been implemented using OpenCV library and tested on OMAP 35x EVM and BeagleBoard-xM based on Texas Instruments OMAP3530 and DM3730 processors, respectively. Analysis of improved median flow was performed over actual video sequences. The results obtained show versatility and computational robustness of the algorithm, which makes it promising for embedded application based on ARM processors. [ABSTRACT FROM AUTHOR]

This article analyzes the main directions of counterintelligence activities of Soviet special services on the territory of Ukraine against the Nazi invaders and occupiers in the period of 1941-1944. The efforts, aimed at neutralization of subversive actions of enemy agents, espionage, intelligence and information network are studied. The methods of operational work, aimed to identify collaborators in different groups of contemporary Ukrainian society and countering opposite political-military forces are disclosed. [ABSTRACT FROM AUTHOR]

The impact of a magnetic isotope effect on the reactions of radical pairs containing radical ions with a heavy atom (UO) has been studied; in the future, the findings can be used to solve practical problems involving a new method of enrichment of uranium isotopes in chemical reactions owing to differences in their magnetic properties. The magnetic isotope effect of uranium can be the basis for an effective method of separating uranium isotopes (U, U, U). Based on the theoretical and experimental studies, the specific features of the behavior of natural and artificial uranium isotopes in chemical reactions attributed to the fundamental properties of their nuclei and the possibility of using both waste of enriched uranium ores (tailings in tailing ponds) and spent nuclear fuels as a nuclear fuel have been substantiated. The behavior of natural and artificial even isotopes of the isotope mixture in a nuclear fuel (U, U, U), which are harmful impurities that absorb a portion of thermal neutrons and worsen the homogeneity of the fuel, has been studied. [ABSTRACT FROM AUTHOR]

The spatial resolution of a scanning tunneling microscope (STM) can be enhanced using light element-terminated probes with spatially localized electron orbitals at the apex atom. Conductive diamond probes can provide carbon atomic orbitals suitable for STM imaging with sub-Ångström lateral resolution and high apex stability crucial for the small tunneling gaps necessary for high-resolution experiments. Here we demonstrate that high spatial resolution can be achieved in STM experiments with single-crystal diamond tips, which are generally only considered for use as probes for atomic force microscopy. The results of STM experiments with a heavily boron-doped, diamond probe on a graphite surface; density functional theory calculations of the tip and surface electronic structure; and first-principles tunneling current calculations demonstrate that the highest spatial resolution can be achieved with diamond tips at tip–sample distances of 3–5 Å when frontier p-orbitals of the tip provide their maximum contribution to the tunneling current. At the same time, atomic resolution is feasible even at extremely small gaps with very high noise in the tunneling current. [ABSTRACT FROM AUTHOR]

Purpose: To investigate the IL-2, IL-4, IL-6, IL-8, IL-10, TNF-α, IL-1β, IFN-γ at the local and system levels in endometrial polyps and hyperplasia in premenopausal women; to assess whether three-dimensional power Doppler indices can discriminate between hyperplasia and proliferative endometrium. Materials and methods: The prospective analysis included 80 premenopausal women with the suspicion of endometrial hyperplasia and endometrial polyp according to 2D ultrasonography data. Three groups of patients were analyzed according to histological data. There were 25 women with simple endometrial hyperplasia without atypia (the first study group), 15 patients with hyperplastic endometrial polyps (the second study group) and 40 healthy women with endometrium in the early proliferative phase (control group) in premenopausal age. The levels of some cytokines were determined by enzyme linked to immunosorbent assay in serum and in aspirates from the uterus cavity. Three-dimensional power Doppler indexes of the uterus and endometrium were measured in endometrial hyperplasia and proliferative endometrium. Results: Significant dysfunctional changes of local immune system of uterine mucosa in endometrial hyperplasia and endometrial polyp are expressed in activation of pro-inflammatory cytokines, with a deficit of anti-inflammatory cytokines. Endometrial three-dimensional power Doppler indices of uterine and endometrium were significantly higher in endometrial hyperplasia. Conclusions: The local secretion imbalance of pro- and anti-inflammatory cytokines is present in endometrial hyperplasia and polyps in premenopausal age. Endometrial perfusion increases in endometrial hyperplasia by using three-dimensional power Doppler sonography in comparison with healthy women. [ABSTRACT FROM AUTHOR]

The results have been reported of the experiments on nanoscratching and nanoindentation of the surface of silicon using scanning tunneling microscope equipped with diamond semiconducting probe. Physical phenomena in silicon occurring at various contact pressures have been discussed. [ABSTRACT FROM AUTHOR]

The results of studying the structure of diamond single crystals grown by the temperature gradient method with the aim to obtain samples having maximum uniform characteristics for manufacturing probes for scanning electron microscopes with a specified axial orientation and controlled distribution of the dopant have been considered. It has been shown that the use of similar probes in scanning tunneling microscopy decreases the probability of incidental tunneling channels with participation of the surface states caused by the presence of boron atoms in the diamond structure and increases the reliability of experimental data. The high stability of monocrystalline diamond probes and the possibility to attain the atomic resolution with the help of them have been demonstrated by the investigations of the (0001) graphite plane using scanning tunneling microscopy. [ABSTRACT FROM AUTHOR]

The assessment of the resolution of scanning tunneling microscope when operated in the scanning mode has been made based on the analysis of the tunneling current on parameters of diamond tip-sample system. The scanning parameters and accuracy of supporting the constant tunneling current by the system of the instrument feedback, at which the presence of the atomic resolution is possible in the case of a single channel of tunneling, have been defined. An alternative (in respect to the best known publications) explanation of the hexagonal structure of the pyrolytic graphite surface observed with atomic resolution has been suggested. The problem of multichannel tunneling caused by the presence of several nanoprotrusions in the diamond probe test zone that initiate tunneling and impair the resolution of a scanning tunneling microscope is discussed. [ABSTRACT FROM AUTHOR]

Background Underground coal mining is an expanding industry in Ukraine, yet little is known about the burden of respiratory disease among Ukrainian miners. Methods A Fogarty International Center-supported collaboration between researchers at the University of Illinois and the Institute of Occupational Health in Kyiv, Ukraine formed to improve capacity for conducting and monitoring medical surveillance among Ukrainian coal miners. A cross-sectional survey among a random sample of working and former miners was conducted; demographic, work, and health information were collected using a standardized questionnaire. Weighted prevalence rates were calculated and predictors of respiratory symptoms explored. Results Improvements in infrastructure, including spirometry and chest radiography testing, transformed medical surveillance among these miners. Results from the health study included that the prevalence of respiratory symptoms was higher among former compared to current miners (shortness of breath 35.6% vs. 5.1%; chronic bronchitis 18.1% vs. 13.9%, respectively). A statistically significant exposure-response relationship was observed between years mining and respiratory symptoms in former miners and between years mining at the coal face and respiratory symptoms among current miners. Evidence of downward bias from the healthy worker survivor effect was observed. Conclusions This successful international collaboration built a sustainable infrastructure for conducting workplace medical surveillance and research. The resulting study was the first in the western literature to report on respiratory symptoms in this population; likely underestimation of disease rates due to selection and measurement biases was demonstrated. Efforts should continue to build this collaboration and to characterize and reduce respiratory illness among Ukrainian coal miners. Am. J. Ind. Med. 55:1099-1109, 2012. © 2011 Wiley Periodicals, Inc. [ABSTRACT FROM AUTHOR]

The absorption and circular dichroism (CD) spectra of LaGaSiO langasite crystals doped with Pr, Ho, and Er ions have been studied in the wavelength range of 350-700 nm. The electronic transitions of these ions, which replace La3+ ions in the 3 e position with the symmetry 2, are observed in the spectra. All transitions are active in both the absorption and CD spectra. The dipole strengths D, rotational strengths R, and anisotropy factors g have been calculated for well-resolved bands. Some features are noted for the spectra that were obtained, and their relationship with the structure disorder is considered [ABSTRACT FROM AUTHOR]

The existing technologies for industrially manufactured GDL and their decomposition to the level of the individual constituents were analyzed and systematized. The cost and output of products manufactured with these technologies were compared. It was shown that the technology for manufacturing carbon-polymer paper using fluoropolymers simultaneously as binder and water repellent and the technology for a sheet in the form of a nonwoven has the lowest cost and highest output. If the existing technologies are brought to the large-scale industrial level, GDL made from TEG can be of minimal cost. [ABSTRACT FROM AUTHOR]

Experimental results of the use of a scanning probe microscope having a nanometric resolution in surface machining have been considered. Specific features of the device are a tip of boron-doped diamond single crystal and electromagnetic system of measuring a nanointeraction between the tip and sample surface. Three-dimensional images of gold and silicon surfaces after nanocleaning and nanoscratching have been demonstrated. The possibilities to use diamond nanotools for making elements of nanoelectronics have been discussed. [ABSTRACT FROM AUTHOR]

Based on the results of the experimental studies of the temperature dependence of the yield stress of single crystals of TiNi alloys and of the mechanism of the mechanical twinning of the B2 phase as a martensite-type local reversible phase transformation, the asymmetry of the mechanical behavior of these materials during tension and compression in the [001] direction has been investigated. It is shown that a specific feature of this mechanism is the fact that the critical mode of distortion which determines stresses during mechanical twinning is a homogeneous deformation of transformation of the Bain-deformation type. To analyze the asymmetry of these stresses during tension and compression, a concept of the factor of normal stresses reduced to the principal axes of the tensor of the homogeneous deformation of transformation is introduced. It is shown that this factor can be used for analyzing the asymmetry of the mechanical behavior of single crystals of TiNi alloys. [ABSTRACT FROM AUTHOR]

The article discusses the study which examines the assumption that the asymmetry of titanium-nickel (TiNi) alloys' stress can support the asymmetry in their yield stress under the conditions of plastic deformation according to the mechanical twinning mechanism. It employs an electron-microscopic investigation of the asymmetric yield in [001] single crystals of TiNi alloys and the atomic model of twinning which is considered as the direct plus reverse martensite transformation.

Tensor of distortions upon the formation of a {113} deformation twin by the mechanism of a combined (forward-plus-reverse) (occurring on an alternative transformation system) martensitic transformation in the B2 phase of titanium nickelide has been analyzed theoretically in the approximation of small deformations using the model of martensitic transformations based on the concept of “freezing” of cooperative thermal vibrations of atoms in close-packed atomic planes in metals. It is shown that this mechanism satisfactorily describes not only the reorientation angle but also the habit plane of the twin. [ABSTRACT FROM AUTHOR]

No appreciable disorders of cellular immunity were detected in patients with glandular cystic endometrial hyperplasia. Atypical endometrial hyperplasia was associated with quantitative changes in T lymphocytes and their subpopulations, decreased level of lymphocytes carrying activation antigens, and increased count of natural killers. These changes can be characterized as immunocompensation. [ABSTRACT FROM AUTHOR]

This paper presents, for the general relativistic case, a theoretical study of nonresonance spontaneous bremsstrahlung by an electron scattered by a nucleus in the field of two elliptically polarized light waves propagating in the same direction. We show that there are two significantly different kinematic regions: the noninterference region where the main multiphoton parameters are the Bunkin-Fedorov quantum parameters γ[sub 1,2], and the interference region where interference effects play an important role and where the quantum interference parameters a(±) act as multiphoton parameters. We encounter the spontaneous interference bremsstrahlung effect in two cases: in the special case of the same linear polarization of both waves, and in the general case of elliptical polarization of the waves. The effect manifests itself in the interference region and is due to stimulated, correlated emission and absorption of photons of both waves. For moderately strong fields, we find the cross sections of spontaneous bremsstrahlung by an electron scattered by a nucleus in the given kinematic regions. Finally, we show that the differential cross section in the interference region with correlated emission (absorption) of equal numbers of photons of both waves can be much greater than the corresponding cross section in any other geometry. [ABSTRACT FROM AUTHOR]

The interaction of 2-amino-1,3,4-oxadiazole-5-carboxamidoxime with nitriles in the presence of ZnCl and HCl or with trichloroacetic anhydride affords 2-amino-5-(5R-1,2,4-oxadiazolyl-3)-1,3,4-oxadiazoles. Their reactions with N-nucleophiles have been studied. [ABSTRACT FROM AUTHOR]

Out of 18 strains of Serratia marcescens producing exocellular proteases the strain Serratia marcescens CCEB 415 was selected according to preliminary experiments. It could be shown that the train exhibits proteolytic activity reaching up to 10 TU per 1 ml of the culture filtrate in a medium with gelatine and peptone. Two proteolytic enzymes could be demonstrated by means of specific inhibitors EDTA and diisopropyfluorophosphate: metaloprotease with optimum activity at pH 7.5 and serine protease with pH optimum of 10.9. The enzymes were purified on Sephadex and DEAE cellulose columns and by means of gel electrophoresis. However, it was not possible to separate them. The optimum temperature for activity of the mixture of the two enzymes was 50 ° C, molecular weight varied around 37000 (according to gel filtration); certain kinetic characteristics of their activity were determined. Excess subtrate (casein) inhibited activity of the enzyme mixture. Toxicity of proteases expressed as LD units equals 78. 10 TU per larva of Galleria mellonella. [ABSTRACT FROM AUTHOR]

Phospholipase C (Ec 3.1.4.3) obtained from Pseudomonas chlororaphis was purified 70-fold and its activity toward various substrates was determined. The enzyme was found to have no toxic effect either on larvae of Galleria mellonella or on the rabbit. The molecular weight of the enzyme was approximately 54,000, its pH optimum 7.5 and the isoelectric point at pH 6.3. The biochemical and toxogenic properties of the enzyme were compared with those of Bacillus cereus and of Clostridium perfringens phospholipases. [ABSTRACT FROM AUTHOR]

The conditions of phospholipase C (EC 3.1.4.3) production by a strain of Bacillus cereus and a method of its preparation are described. The molecular weight of the enzyme as determined by gel filtration is 24,000. Comparison of several characteristics of the enzyme (pH optimum, immunospecificity, mobility in discelectrophoresis) with that from Clostridium perfringens shows them to be different molecules. [ABSTRACT FROM AUTHOR]

Extra-cellular proteinases of Pseudomonas aeruginosa toxic for larvae of the greater wax moth were separated from the culture filtrate by means of ammonium sulphate precipitation, chromatography on DEAE cellulose, gel filtration on Sephadex G-75 and preparative disc-electrophoresis respectively. The five proteinases isolated were characterized by pH optima, molecular weights, elastase and collagenase activities. [ABSTRACT FROM AUTHOR]

Proteinases produced by Pseudomonas aeruginosa are toxic for galleria larvae and their LD differ from one enzyme to the other. The most toxic enzyme has a specific affinity to some protein fractions of insect haemolymph as shown by disc electrophoresis. [ABSTRACT FROM AUTHOR]