Laser-induced breakdown spectroscopy (LIBS) provides a rapid, cost-effective, and extra-sensitive analysis of geological samples to make preliminary conclusions about the presence of valuable ...elements up to the trace levels in the ore. We present the first results of a highly sensitive qualitative analysis of the core samples of geological ore from two boreholes in Latvia (Staicele 1, from a depth range of 794–802 m, and Garsene (Subate) 2A, from a depth range of 1102–1103 m) using LIBS. Our measurements using this technique confirmed the high iron content and indicated traces of rare and high in-demand metals (such as Ti, V, Co, Sm, etc.) in the sample from Staicele, renewing interest in studying boreholes across Latvia. The presented pilot studies demonstrated effectiveness and unique possibility in performing a very sensitive and time-saving qualitative analysis of the composition of samples of ores from the old but still valuable borehole cores by using the LIBS method. We compare these measurements with other methods of sample analysis.
Microelements are important for stabilizing cell structures, but in deficient conditions they can stimulate alternative pathways and cause disease. This study was aimed to presents the monitoring ...data on the biogeochemical situation of pasture ecosystems in the Astrakhan region, southern Russia. Microelements in the collected samples from the pasture ecosystem, as well as the organs and tissues of Soviet Merino sheep, were determined by atomic absorption method. It was found a low level of microelements in soil, plants and forages of the ecosystem in the Astrakhan region. In addition, it was found a low level of microelements (selenium, iodine, and cobalt) in the organs and tissues of Merino sheep. Hypomicroelementosis in sheep leads to oxidative stress in animals, lower productivity and decrease the immunity of animals, which can be a predisposing for other diseases.
Common carotid artery (CCA) thrombosis is a rare cause of ischemic stroke. In available literature, we found no studies devoted to cerebral revascularization for CCA occlusion in acute period of ...ischemic stroke. Successful treatment of concomitant occlusion of CCA, internal (ICA) and external carotid arteries (ECA) with microvascular anastomoses is very interesting for various specialists. To demonstrate the possibility of contralateral cerebral revascularization in a patient with CCA, ECA and ICA occlusion in acute period of ischemic stroke. Two-stage intervention was performed in a patient with ischemic stroke and carotid artery occlusion. At the first stage, EICMA was formed between the right superficial temporal artery and the M4 branch of the middle cerebral artery (MCA), at the second stage - anastomosis between the right and left ECAs using an autologous arterial graft from the radial artery. There is no generally accepted surgical strategy for CCA occlusion. Contralateral revascularization with blood flow redirecting from the right carotid artery to the left one makes it possible to avoid thrombectomy from the affected CCA and ECA. We have undertaken this method for the first time. We have not found such an approach in the available literature. This report demonstrates the possibility of successful cerebral revascularization in acute period of ischemic stroke in patients with combined occlusion of CCA, ICA and ECA.
The effective way of enhancing resistance to deterioration of the parts is the change of surface properties due to coating with the required properties. Since the deposition process takes place at an ...elevated temperature, it is necessary to ensure the absence of phase and structural transformations in the metal, mixing of materials, changes in the chemical composition of the coating. The use of plasma spraying at the transport management facility showed a sufficiently high quality of the coating. However, the metallographic analysis showed the presence of discontinuities at the interface in the form of pores, oxide film and sections of decarburized steel. In the case of the process of melting-spraying, the overheating areas of the base metal are formed, which leads to disadvantages similar to the deposition process. To ensure the minimal thermal impact on the part, the thermal field calculations are required. For this purpose, the time of local melting of the part by a single-phase plasma jet was calculated. The temperature field of a part in which heat is transferred by thermal conductivity, the solution of the differential equation of thermal conductivity is described. The boundary conditions of three genera are formulated. The first kind is the distribution of temperature on the enclosing surfaces. The second kind - the task on the surface of the part of the heat flux density. The third kind - setting the temperature of the medium, which acts as a plasma jet, washing the surface of the part, and the intensity of heat exchange. The mathematical model of melting of the product is constructed. The formula for calculating the reflow time is derived. The temperature distribution expressions for the molten and solid zones are obtained by the solution of the problem with moving boundaries by the Fourier's method. On the basis of theoretical calculations it is proposed to increase the strength of the sprayed layer with the base to apply the process of plasma spraying with preliminary local melting by periodic exposure to a single-phase plasma jet.
The important aim of this work is a critique of dialectics of Hegel. Two point of view about the character of the dialectics are researched. Corresponding to the first at them, the dialectic is a ...myth. Corresponding to the second view, dialectics is a theory that reflects the real state of things and is the future of philosophy. According to this point of view, mind and reality are developing dialectical triad, which includes a thesis, antithesis and synthesis. The definition of metaphysics of Hegel, which he creates by identifying two types of contradictions is criticized. Hegel identifies the logical contradictions that exist in mind and contradictions that exist in reality in the form of conflict of interests, the struggle for survival.
The authors propose a method of quantitative description of regularities, related to the influence of dimensions and localization of different areas of the cathode emitting surface, on the volt-amp ...diagrams. They report numerical experiments in the field of cathode electronics, including the usage of the basic system containing cathodes with edge screening.
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