Hydrodynamic bidimensional stability of detonation wave solutions for reactive mixtures

The structure of a planar detonation wave is analyzed for an Eulerian mixture of ideal gases undergoing the symmetric reversible explosive reaction A1 + A1 = A2 + A2. The chemical rate law is derived from the reactive Boltzmann equation, showing a detailed chemical kinetics in terms of a second-order reaction rate. The hydrodynamic bidimensional stability of the detonation wave is also investigated using a normal mode approach, when small time-space transverse disturbances affect the shock wave location. A suitable numerical technique is here proposed in order to solve the stability problem and numerical results are provided illustrating the detonation wave structure and its instability spectrum.The paper is partially supported by Brazilian Research Council (CNPq), by Italian Research Council GNFM-INdAM, and by Portuguese Funds of FCT, CMAT project UID/MAT/00013/2013

On the Wigner function of the relativistic finite-difference oscillator in an external field

The phase-space representation for a relativistic linear oscillator in a homogeneous external field expressed through the finite-difference equation is constructed. Explicit expressions of the relativistic oscillator Wigner quasi-distribution function for the stationary states as well as of states of thermodynamical equilibrium are obtained and their correct limits are shown.Comment: 12 pages, 6 figures, IOP styled LaTeX, to be published in Journal of Physics

Endoscopic treatment for bulbar-membranous urethral obliteration: evaluation of the efficacy and safety

Introduction. The problem of endoscopic treatment for urethral strictures and obliterations remains unresolved. It is necessary to note that the effectiveness depends not only on the right indications, but also on the surgical technique and the study of the postoperative period management.Objective. To evaluate the efficacy and safety of endoscopic treatment of patients with bulbar-membranous urethral obliteration.Materials and methods. The study included 103 patients aged 20 to 89 years with bulbar-membrane urethral obliteration, who, for some reason or another, cannot perform urethroplasty. The patients underwent endoscopic recanalization of the urethra under X-ray control with further circular transurethral electroresection (TUR) of the scar tissues in the urethral obliteration zone (after 6 – 7 days).Results. The average age of the patients was 61.1 ± 18.3 years. After the operation, self-urination was restored in all patients. The average maximum urine flow rate (Q max) before discharge from the hospital was 12.6 ± 0.5 ml/s. Throughout the follow-up period, Q max tended to increase and at the end of the study (36 months) reached values of 16.5 ± 0.5 ml/s. During the first year of follow-up, 18 (17.5%) patients developed recurrent urethral stricture. Seventeen (16.5%) patients underwent repeated circular TUR of scar tissue in the zone of recurrent stricture. The effectiveness of the treatment was 90.0%.Conclusion. Endoscopic urethral recanalization followed by TUR of scar tissue in the obliteration zone is an effective and safe method in the treatment of bulbar-membranous urethral obliteration with length less than 1.0 cm

METHOD OF CALCULATING THE PROCESSES OF ICE GENERATION

The article presents an approach to the numerical implementation of the two-phase Stefan problem, useful in creating new and improving existing technical devises for ice production. The features of the author’s calculation method, which favorably distinguish it from similar developments, are given. The results of calculations are presented and they are discussed.В статье представлен подход к численной реализации двухфазной задачи Стефана, полезный при создании новых и совершенствовании существующих технических устройств для получения льда. Приведены особенности авторской методики расчета, выгодно отличающие ее от подобного рода разработок. Представлены результаты расчетов и проведено их обсуждение

Overview: Recent advances in the understanding of the northern Eurasian environments and of the urban air quality in China – a Pan-Eurasian Experiment (PEEX) programme perspective

The Pan-Eurasian Experiment (PEEX) Science Plan, released in 2015, addressed a need for a holistic system understanding and outlined the most urgent research needs for the rapidly changing Arctic-boreal region. Air quality in China, together with the long-range transport of atmospheric pollutants, was also indicated as one of the most crucial topics of the research agenda. These two geographical regions, the northern Eurasian Arctic-boreal region and China, especially the megacities in China, were identified as a “PEEX region”. It is also important to recognize that the PEEX geographical region is an area where science-based policy actions would have significant impacts on the global climate. This paper summarizes results obtained during the last 5 years in the northern Eurasian region, together with recent observations of the air quality in the urban environments in China, in the context of the PEEX programme. The main regions of interest are the Russian Arctic, northern Eurasian boreal forests (Siberia) and peatlands, and the megacities in China. We frame our analysis against research themes introduced in the PEEX Science Plan in 2015. We summarize recent progress towards an enhanced holistic understanding of the land–atmosphere–ocean systems feedbacks. We conclude that although the scientific knowledge in these regions has increased, the new results are in many cases insufficient, and there are still gaps in our understanding of large-scale climate–Earth surface interactions and feedbacks. This arises from limitations in research infrastructures, especially the lack of coordinated, continuous and comprehensive in situ observations of the study region as well as integrative data analyses, hindering a comprehensive system analysis. The fast-changing environment and ecosystem changes driven by climate change, socio-economic activities like the China Silk Road Initiative, and the global trends like urbanization further complicate such analyses. We recognize new topics with an increasing importance in the near future, especially “the enhancing biological sequestration capacity of greenhouse gases into forests and soils to mitigate climate change” and the “socio-economic development to tackle air quality issues”

Magneto switch microcircuit and wind speed measurement’s sensor on its base

The magneto switch microcircuit on the base of Hall-effect is developed. The electric scheme of the magneto sensitive IC was designed and its basic technical characteristics are described. The gauge of wind speed on its base is fabricated

Короткий - діапазон порядку AgGaS2 (Se2) аморфних з'єднання і епітаксіального зростання плівок на їх основі з надбудовних клітинами

The short-range order parameters of AgGaS2(Se2) thin amorphous films have been investigated. The interatomic distances and numbers of the nearest neighbors have been determined from the atom radial distribution curves. It is shown, that the matrices of amorphous films consists from tetrahedral and octahedron surroundings of atoms. The opportunity of existence of super structural phase of AgGaS2 is established and the oriental parities existing between epitaxially accruing layers of a film and a substrate.Параметри ближнього порядку з AgGaS2 (Se2) тонких аморфних плівок були досліджені. Міжатомні відстані і числа найближчих сусідів були визначені з атома кривих радіального розподілу. Показано, що матриці аморфних плівок складаються з тетраедричних і октаедричних оточення атомів. Можливість існування супер структурних фаз AgGaS2 створений і східних співвідношення, існуючі між епітаксійними нарахуваннями шарів плівки і підкладкою