Method for Simplified Simulation of the Pseudo-Viscosity of the Flows with Solid Particles

The short review of the solid phase pseudo-viscosity CFD-simulation methods is presented. The simplified method based on Einstein's equation, experimental data approximation, and the multiphase mixture model for the solid phase pseudo-viscosity simulation is proposed. The results of the experimental verification of the proposed method are presented, its terms of use are determined. © Published under licence by IOP Publishing Ltd

Analytical study of non-linear transport across a semiconductor-metal junction

In this paper we study analytically a one-dimensional model for a semiconductor-metal junction. We study the formation of Tamm states and how they evolve when the semi-infinite semiconductor and metal are coupled together. The non-linear current, as a function of the bias voltage, is studied using the non-equilibrium Green's function method and the density matrix of the interface is given. The electronic occupation of the sites defining the interface has strong non-linearities as function of the bias voltage due to strong resonances present in the Green's functions of the junction sites. The surface Green's function is computed analytically by solving a quadratic matrix equation, which does not require adding a small imaginary constant to the energy. The wave function for the surface states is given

ОПРЕДЕЛЕНИЕ УРОВНЯ НАСТОРОЖЕННОСТИ (INDEX SUSPICION) В ОТНОШЕНИИ МОЧЕПОЛОВОГО ТУБЕРКУЛЕЗА У СПЕЦИАЛИСТОВ РАЗЛИЧНОГО ПРОФИЛЯ

Polymorphism of clinical manifestations and absence of pathognomic symptoms are typical of urogenital tuberculosis. Since anti-microbial agents are widely used (fluoruquinolones, amikacin, rifampicin), it is more difficult to verify the diagnosis by pathomorphologic and bacteriological methods. The index of suspicion and certain required minimum level of knowledge on urogenital tuberculosis are crucial for its early diagnostics.Materials and methods. In order to assess the level of knowledge in doctors specializing in different fields (urologists, gynecologists, general practitioners, phthisiologists) about specific symptoms and early diagnostics of urogenital tuberculosis and to evaluate the level of their awareness of this disease, 265 specialists had a test in the form of a questionnaire. To define preferences of specialists when choosing specific therapy of infectious inflammatory disorders of the urogenital system, the answers to the questionnaire given by 2 groups of doctors were analyzed, Group 1 (103 persons) included urologists, gynecologists and phthisiologists from medical units of Novosibirsk Region and city of Novosibirsk, Group 2 (298 persons) included interns and residents of Novosibirsk State Medical University by the Russian Ministry of Health.Results. There was no significant difference between the level of knowledge about urogenital tuberculosis among the specialists: urologists, gynecologists, and general practitioners gave the right answers in 59.2-63.7% of cases; phthisiologists had a better level of knowledge and 77.2% of their answers was right. In every third case, the choice of anti-microbial agents for empiric therapy of acute and chronic cystitis was not the best option regarding the drug resistance and inhibiting action against M. tuberculosis.Conclusion: The results of the questionnaire survey showed the low level of knowledge about urogenital tuberculosis among the specialists of general medical services (urologists, gynecologists, general practitioners). The high number of antibacterial agents with tuberculostatic action which were mentioned as drugs for the empiric treatment of urogenital disorders reflects the fact that importance of urogenital tuberculosis is underestimated by the specialists. Мочеполовой туберкулез (МПТ) характеризуется полиморфизмом клинических проявлений и отсутствием патогномоничных симптомов. В связи с широким применением в общей практике антимикробных препаратов (фторхинолоны, амикацин, рифампицин) возможность верификации диагноза патоморфологически и бактериологически резко снижена. Настороженность врача (index suspicion) и определенный минимум знаний в отношении МПТ выходят в ранней диагностике на первый план.Материал и методы. С целью определения уровня знаний врачами разных специальностей (урологи, гинекологи, терапевты, фтизиатры) особенностей клинической картины и ранней диагностики МПТ, уровня их настороженности в отношении этого заболевания проведено тестирование 265 специалистов. Для определения предпочтений специалистов в выборе эмпирической терапии инфекционно-воспалительных заболеваний мочеполовой системы проанализированы результаты анкетирования врачей урологов, гинекологов и фтизиатров лечебных учреждений Новосибирской области и г. Новосибирска (1-я группа ‒ 103 человека), а также интернов, ординаторов ГБОУ ВПО «НГМУ» Минздрава России (2-я группа ‒ 298 человек).Результаты. Существенной разницы между уровнем знаний особенностей МПТ у специалистов не выявлено: урологи, гинекологи и терапевты дали правильные ответы в 59,2-63,7% случаев; закономерно лучшую подготовку по этому вопросу продемонстрировали фтизиатры, которые верно ответили в 77,2% случаев. Выбор антимикробных препаратов в качестве эмпирической терапии острого и хронического цистита в трети случаев не был оптимальным в точки зрения резистентности возбудителя и ингибирующего действия на M. tuberculosis.Вывод. Результаты исследования показали, что уровень знаний по МПТ у специалистов общей лечебной сети (урологи, гинекологи, терапевты) недостаточен. Высокая доля группы антибактериальных препаратов, обладающих туберкулостатическим действием, которые были указаны как препараты для эмпирической терапии мочевой инфекции, отражает серьезную проблему недооценки значимости мочеполового туберкулеза среди специалистов.

Preliminary results from the Russian-American Gallium Experiment Cr-neutrino source measurement

The Russian-American Gallium Experiment has been collecting solar neutrino data since early 1990. The flux measurement of solar neutrinos is well below that expected from solar models. We discuss the initial results of a measurement of experimental efficiencies by exposing the gallium target to neutrinos from an artificial source. The capture rate of neutrinos from this source is very close to that which is expected. The result can be expressed as a ratio of the measured capture rate to the anticipated rate from the source activity. This ratio is 0.93 + 0.15, - 0.17 where the systematic and statistical errors have been combined. To first order the experimental efficiencies are in agreement with those determined during solar neutrino measurements and in previous auxiliary measurements. One must conclude that the discrepancy between the measured solar neutrino flux and that predicted by the solar models can not arise from an experimental artifact

Measurement of the response of a gallium metal solar neutrino experiment to neutrinos from a [Formula Presented] source

The neutrino capture rate measured by the Russian-American Gallium Experiment is well below that predicted by solar models. To check the response of this experiment to low-energy neutrinos, a 517 kCi source of [Formula Presented]Cr was produced by irradiating 512.7 g of 92.4%-enriched [Formula Presented]Cr in a high-flux fast neutron reactor. This source, which mainly emits monoenergetic 747-keV neutrinos, was placed at the center of a 13.1 ton target of liquid gallium and the cross section for the production of [Formula Presented]Ge by the inverse beta decay [Formula Presented] was measured to be [Formula Presented] The ratio of this cross section to the theoretical cross section of Bahcall for this reaction is 0.95 ±0.12 [Formula Presented] (theor) and to the cross section of Haxton is 0.87±0.11 (expt)±0.09 (theor). This good agreement between prediction and observation implies that the overall experimental efficiency is correctly determined and provides considerable evidence for the reliability of the solar neutrino measurement. © 1999 The American Physical Society

The Russian-American gallium experiment (SAGE) Cr neutrino source measurement

No description supplie

Quantum thermal transport in nanostructures

In this colloquia review we discuss methods for thermal transport calculations for nanojunctions connected to two semi-infinite leads served as heat-baths. Our emphases are on fundamental quantum theory and atomistic models. We begin with an introduction of the Landauer formula for ballistic thermal transport and give its derivation from scattering wave point of view. Several methods (scattering boundary condition, mode-matching, Piccard and Caroli formulas) of calculating the phonon transmission coefficients are given. The nonequilibrium Green's function (NEGF) method is reviewed and the Caroli formula is derived. We also give iterative methods and an algorithm based on a generalized eigenvalue problem for the calculation of surface Green's functions, which are starting point for an NEGF calculation. A systematic exposition for the NEGF method is presented, starting with the fundamental definitions of the Green's functions, and ending with equations of motion for the contour ordered Green's functions and Feynman diagrammatic expansion. In the later part, we discuss the treatments of nonlinear effects in heat conduction, including a phenomenological expression for the transmission, NEGF for phonon-phonon interactions, molecular dynamics (generalized Langevin) with quantum heat-baths, and electron-phonon interactions. Some new results are also shown. We also briefly review the experimental status of the thermal transport measurements in nanostructures.Comment: 24 pages, 10 figures, over 200 reference