101 research outputs found
X-ray diffraction study and luminescence of agates of Southern Siberia
Central part of Kuznetsk Basin is known in the narrow circle of researchers as one of the regions of Siberia where agate mineralization is widespread. In spite of rather wide distribution of these quartz-chalcedony aggregates, still there are some unresolved issues about their origin. In this context it may be informative to use such methods as luminescence analysis and estimation of crystallinity indexes of minerals which constitute agates. Layer-by-layer X-ray diffraction study of minerals which make up distinct layers of agates and onyxes allowed identifying three minerals alternating: chalcedony, quartz and (less frequently) cristobalite. Calculation of crystallinity indexes of all of the layers with use of X-ray diffraction analysis helped to find changes of proportion between two states of silica – high-molecular (polymerized) and monomeric. X-ray luminescence analysis results confirmed this finding. Authors suppose that monomeric state is particularly related to high value of crystallinity index and presence of defects which are responsible for short-wavelength luminescence (280 nm)
Features of Spiritual and Moral Education of Students of Educational Organizations of Secondary Vocational Education
В статье рассматриваются особенности духовно-нравственного воспитания студентов образовательных организаций среднего профессионального образования и основные проблемы и пути их решения.The article discusses the features of spiritual and moral education of students of educational institutions of secondary vocational education and the main problems and ways to solve them
Reduction Operators of Linear Second-Order Parabolic Equations
The reduction operators, i.e., the operators of nonclassical (conditional)
symmetry, of (1+1)-dimensional second order linear parabolic partial
differential equations and all the possible reductions of these equations to
ordinary differential ones are exhaustively described. This problem proves to
be equivalent, in some sense, to solving the initial equations. The ``no-go''
result is extended to the investigation of point transformations (admissible
transformations, equivalence transformations, Lie symmetries) and Lie
reductions of the determining equations for the nonclassical symmetries.
Transformations linearizing the determining equations are obtained in the
general case and under different additional constraints. A nontrivial example
illustrating applications of reduction operators to finding exact solutions of
equations from the class under consideration is presented. An observed
connection between reduction operators and Darboux transformations is
discussed.Comment: 31 pages, minor misprints are correcte
COMPARATIVE CHARACTERISTICS OF IMMUNOLOGICAL RECONSTRUCTION OF WHITE MICE IMMUNIZED BY CELL WALL OF DIFFERENT SUBSPECIES OF FRANCISELLA TULARENSIS
At present, development of effective vaccines of new generation is an actual problem, in particular concerning the tularemia causative agent. It determines the need to search antigen determinants with high immunogenic activity. Some authors demonstrate that outer membrane proteins of Francisella tularensis possess immunological activity. This fact gave occasion to isolation and comprehensive study of F tularensis cellular envelopes as a perspective component in vaccine engineering. The influence of cell walls of F. tularensis was studied for morphological changes in immunocompetent organs of experimental animals. Cell walls were obtained from three virulence strains of living cultures: F. tularensis subsp. mediaasiatica А-61, F. tularensis subsp. nearctica В-399 A-Cole, F. tularensis subsp. holarctica 306 and vaccine strain F. tularensis subsp. holarctica 15 (extracted by Research Institute of Epidemiology and Hygiene). Cell walls of different subspecies of F. tularensis stimulate the production of antibody forming cells and cell proliferation more in T-dependent zones of lymph nodes and spleen. It has been determined that these antigen preparations do not cause stress reaction of the experimental animal organisms. Basing on the findings, we made a conclusion that there is a need for further detailed investigation of immunogenic properties of CE F. tularensis subsp. holarctica 306, F. tularensis subsp. mediasiatica А-61 and F. tularensis subsp. tularensis B-399 A-Cole as perspective components in development of tularemia vaccines
Serum lipid profile and clinical characteristics of patients with xanthelasma palpebrarum
Severe plastic deformation for producing superfunctional ultrafine-grained and heterostructured materials: An interdisciplinary review
Ultrafine-grained and heterostructured materials are currently of high interest due to their superior mechanical and functional properties. Severe plastic deformation (SPD) is one of the most effective methods to produce such materials with unique microstructure-property relationships. In this review paper, after summarizing the recent progress in developing various SPD methods for processing bulk, surface and powder of materials, the main structural and microstructural features of SPD-processed materials are explained including lattice defects, grain boundaries and phase transformations. The properties and potential applications of SPD-processed materials are then reviewed in detail including tensile properties, creep, superplasticity, hydrogen embrittlement resistance, electrical conductivity, magnetic properties, optical properties, solar energy harvesting, photocatalysis, electrocatalysis, hydrolysis, hydrogen storage, hydrogen production, CO2 conversion, corrosion resistance and biocompatibility. It is shown that achieving such properties is not limited to pure metals and conventional metallic alloys, and a wide range of materials are currently processed by SPD, including high-entropy alloys, glasses, semiconductors, ceramics and polymers. It is particularly emphasized that SPD has moved from a simple metal processing tool to a powerful means for the discovery and synthesis of new superfunctional metallic and nonmetallic materials. The article ends by declaring that the borders of SPD have been extended from materials science and it has become an interdisciplinary tool to address scientific questions such as the mechanisms of geological and astronomical phenomena and the origin of life
Control exerted by rock anisotropy on chemical compaction localization in Bahamian-type peritidal limestones of the Apulian Platform (Italy)
In this contribution we present the results of a work aimed at assessing the geological, petrophysical and mechanical factors affecting chemical compaction localization (overburden-inducedpressure solution) in tight, Bahamian-type platform limestones. The products of such compaction include bed-parallel stylolites, which represent structural features that may affect the permeability of the rock due to the presence of clayish insoluble residue along them. By combining field and laboratory studies
(sedimentological, structural, petrographic and statistical analyses), we have investigated Upper Jurassic and Cretaceous peritidal limestones originally pertaining to the Apulian Platform realm and now exposed in three distinct Italian locations: Maiella Mountain, Gargano Promontory and Murge Plateau. All these limestones are crosscut by bed-parallel stylolites that are more abundant (up to 10 times longer and less spaced from each other) in the laminated microbial bindstones than in the other,
more isotropic carbonate facies (mostly structureless lime mudstones to grainstones). A first-order control of bed thickness on spacing and, hence, localization of bed parallel stylolites is excluded. By contrast, lithological factors clearly played a major role on localize stylolites within the microbial bindstones. One prominent factor is likely the ubiquitous occurrence in bindstones of bed-parallel laminae. Accordingly, petrographic thin sections display stylolites localized at laminae boundaries. However, bedparallel laminae are ubiquitous also in some grainstones where stylolites are only a little more abundant than in the nonlaminated counterparts. So, other factors peculiar of microbial
bindstones may have dramatically influenced stylolite localization as well. A key factor is probably the ubiquitous occurrence of former fenestral voids that, to date, are mostly filled by coarsely sparry calcite cement. Similar distributions of stylolites in structureless limestones (mudstones to grainstones) are consistent with rock grain size having probably played only a minor role in their localization (stylolites slightly enhanced in muddy limestones). By contrast, clay amount of the rock (0-4%
by volume) seem have not played any significant role in enhancing stylolite localization. To sum up, our results point to a major role played by the lithological characteristics of limestones on the development and localization of bed-parallel stylolites. Additional ongoing laboratory experiments including petrophysical and geomechanical analyses may help to improve these results and to better understand the role played by stylolite localization on the overall rock permeability
Bedding - parallel styolite localization in stromatolitic layers of Bahamian - type peritidal limestones of the Apulian Platform (Italy)
- …