Современные системы интервального регулирования движения поездов железных дорог мира

The review study is devoted to the analysis of the modern systems aimed at enhancing or replacing existing systems of rail automatics and refers to ERTMS (European Union), CTCS (PRC), ATACS (Japan), PTC (Unites States) and ABTS-MSH (Russian Federation). The review study discusses the main approaches and principles applied during the research and development of train traffic interval control systems, modern trends in their developments on public railways in Russia and other countries with the account for the scale of their adoption, offers tentative identification of problems that have arisen at the stages of implementation and operation and evaluation of the outlook for their further improvements.While each system merits detailed study, the prevailed approach focused on comparative system analysis and revealing differences and common tendencies regarding their further evolution.Обзорное исследование посвящено анализу современных систем, направленных на дополнение или замену существующих систем железнодорожной автоматики.Рассматриваются ERTMS (ЕС), CTCS (КНР), ATACS (Япония), PTC (США), АБТЦ-МШ (Россия).Представлены основные подходы и принципы, положенные в основу разработки систем интервального регулирования, современные тенденции их развития на железнодорожных магистралях общего пользования в России и за рубежом с учётом масштабов их применения, основные проблемы, возникшие на этапах внедрения и эксплуатации, а также предложена оценка перспектив дальнейшего совершенствования данных систем.Несмотря на то, что каждая из систем заслуживает отдельного детального рассмотрения, сделана попытка провести системный сравнительный анализ и выявить различия и общие закономерности их последующей эволюции

X-Ray Fluorescence Determination of Trace Gold in an Ion-Exchange Resin

The use of portable X ray optics with a secondary radiator in the determination of trace gold in an ion exchange resin within the mass fraction range of 1–50 ppm is described. It is shown that the secondary radiator design with primary radiation filtering allows one to determine trace gold in an ion exchange resin when the mass fraction of gold is lower than 1 ppm

Equation of state SAHA-S meets stellar evolution code CESAM2k

We present an example of an interpolation code of the SAHA-S equation of state that has been adapted for use in the stellar evolution code CESAM2k. The aim is to provide the necessary data and numerical procedures for its implementation in a stellar code. A technical problem is the discrepancy between the sets of thermodynamic quantities provided by the SAHA-S equation of state and those necessary in the CESAM2k computations. Moreover, the independent variables in a practical equation of state (like SAHA-S) are temperature and density, whereas for modelling calculations the variables temperature and pressure are preferable. Specifically for the CESAM2k code, some additional quantities and their derivatives must be provided. To provide the bridge between the equation of state and stellar modelling, we prepare auxiliary tables of the quantities that are demanded in CESAM2k. Then we use cubic spline interpolation to provide both smoothness and a good approximation of the necessary derivatives. Using the B-form of spline representation provides us with an efficient algorithm for three-dimensional interpolation. The table of B-spline coefficients provided can be directly used during stellar model calculations together with the module of cubic spline interpolation. This implementation of the SAHA-S equation of state in the CESAM2k stellar structure and evolution code has been tested on a solar model evolved to the present. A comparison with other equations of state is briefly discussed. The choice of a regular net of mesh points for specific primary quantities in the SAHA-S equation of state, together with accurate and consistently smooth tabulated values, provides an effective algorithm of interpolation in modelling calculations. The proposed module of interpolation procedures can be easily adopted in other evolution codes.Comment: 8 pages, 5 figure

Synthesis and characterisation of nanocrystalline ZrN PVD coatings on AISI 430 stainless steel

The nanocrystalline films of zirconium nitride have been synthesized using ion-plasma vacuum-arc deposition technique in combination with high-frequency discharge (RF) on AISI 430 stainless steel at 150oC. Structure examinations X-ray fluorescent analysis (XRF), X-ray diffraction analysis (XRD), scanning electron microscopy (SEM) with microanalysis (EDS), and transmission electron microscopy (TEM), nanoidentation method – were performed to study phase and chemical composition, surface morphology, microstructure and nanohardness of coatings. The developed technology provided low-temperature coatings synthesis, minimized discharge breakdown decreasing formation of macroparticles (MPs) and allowed to deposit ZrN coatings with hardness variation 26.6…31.5 GPa. It was revealed that ZrN single-phase coatings of cubic modification with finecrystalline grains of 20 nm in size were formed

Anti-corrosion ceramic coatings on the surface of Nd-Fe-B repelling magnets

The results of vacuum-arc deposition of thin ZrO₂coatings to protect the surface of Nd-Fe-B permanent magnets used as repelling devices in orthodontics are presented. The structure, phase composition and mechanical properties of zirconium dioxide films have been investigated by means of SEM, XRD, EDX, XRF and nanoindentation method. It was revealed the formation of polycrystalline ZrO₂ films of monoclinic modification with average grain size 25 nm. The influence of the ZrO₂ coating in terms of its barrier properties for corrosion in quasi-physiological 0.9 NaCl solution has been studied. Electrochemical measurements indicated good barrier properties of the coating on specimens in the physiological solution environment

РАСЧЕТ СРЕДНЕГО ВЕСА ГРУЗОВОГО ПОЕЗДА

Average weight of freight trains is an important indicator of the use of the existing tonnage rating, power of traction means and defining, in terms of given volume of traffic, size of freight trains movement on sections of railway lines. This indicator plays a leading role in technical and economic calculations, but methods, which are used, provide a basis to seek corrective options. The author offers his interpretation of the well-known formula that is used for selecting optimal tonnage rating of freight trains (characterized by full-length and full-weight) and bases his calculations on certain assumptions. With the help of a modified formula difference of the calculated average weight of about 2.3% is achieved.Средний вес грузового поезда является важнейшим показателем, характеризующим использование действующей весовой нормы, мощности тяговых средств и определяющий при заданных объемах перевозок размеры движения грузовых поездов на участках железнодорожного направления. Показатель играет ведущую роль в технико-экономических расчетах, но используемые при этом методы дают основание искать корректирующие варианты. Автор статьи предлагает свою интерпретацию известной формулы, которая применяется при выборе оптимальных весовых норм грузовых поездов (полносоставных и полновесных) и исходит из определенных предположений. С помощью измененной формулы достигается разница расчетного среднего веса порядка 2,3%

A synoptic comparison of the MHD and the OPAL equations of state

A detailed comparison is carried out between two popular equations of state (EOS), the Mihalas-Hummer-Dappen (MHD) and the OPAL equations of state, which have found widespread use in solar and stellar modeling during the past two decades. They are parts of two independent efforts to recalculate stellar opacities; the international Opacity Project (OP) and the Livermore-based OPAL project. We examine the difference between the two equations of state in a broad sense, over the whole applicable rho-T range, and for three different chemical mixtures. Such a global comparison highlights both their differences and their similarities. We find that omitting a questionable hard-sphere correction, tau, to the Coulomb interaction in the MHD formulation, greatly improves the agreement between the MHD and OPAL EOS. We also find signs of differences that could stem from quantum effects not yet included in the MHD EOS, and differences in the ionization zones that are probably caused by differences in the mechanisms for pressure ionization. Our analysis do not only give a clearer perception of the limitations of each equation of state for astrophysical applications, but also serve as guidance for future work on the physical issues behind the differences. The outcome should be an improvement of both equations of state.Comment: 33 pages, 26 figures. Corrected discussion of Basu & Antia, 2004, ApJ, 606, L85-L8

Cluster-based Superconducting Tunneling Networks

A 2D tunneling network consisting of nanoclusters placed on a surface is studied. It is shown that such a network is capable of transferring large supercurrent at high temperatures. For a realistic set of parameters the damping is quite small, and the smallness is due to strong renormalization of the capacitance of a cluster. The critical field also turns out to be larComment: 18 page