Микротвердость валиков из бронзы ПГ-19М-01, нанесенных как составляющая мултимодального покрытия методом лазерной наплавки

В статье рассматриваются преимущества лазерной наплавки и возможности использования лазерной наплавки для создания мультимодальных покрытий из разнородных металлических материалов. Приведены результаты исследований микротвердости в поперечном сечении наплавленных валиков из алюминиевой бронзы. Показано влияние скорости лазерной наплавки на микротвердость в наплавленных валиках.The advantages and the capabilities of laser cladding are analyses for used laser cladding for applying multimodal coatings from heterogeneous metal work materials. Results of microhardness investigations in cross section of cladding tracks from Al-bronze are exhibited. The influence of cladding velocity on microhardness are examined

Динамика фрикционных процессов при трении нержавеющей стали аустенитного класса 12Х18Н10Т с ультрамелкозернистой структурой

В работе рассматривается экспериментальное исследование динамики фрикционных процессов при трении объемных ультрамелкозернистых материалов. В качестве модельных образцов использовалась нержавеющая сталь аустенитного класса 12Х18Н10Т с ультрамелкозернистой структурой, сформированной методами ABC прессования и прокатки. В процессе сухого трения скольжения осуществлялась регистрация сигналов виброускорений и акустической эмиссии

Estimation of field production profiles in case of asphaltene deposition

In this work, we aimed to predict possible field production scenarios in case of asphaltene deposition based on field data as well as recommend remediation and stimulation measures to mitigate the risks of asphaltene deposition in the reservoir. We considered the influence of asphaltene formation in the near-wellbore of producers on the production data without reservoir pressure maintenance system in one of the oil fields. The asphaltene envelope in the reservoir oil was obtained, and the operating conditions of the field were evaluated under the possibility of asphaltene deposition. According to the results of dynamic modeling, the pressure map was plotted and the low-pressure areas in the near-wellbore were shown, which contributes to the aggravation of the problem associated with the asphaltene envelope. Based on the geometrical features of the low-pressure area, the dependence of the permeability reduction in the near-wellbore of the production well on the operating time was obtained using the asphaltene deposition model proposed by Wang and Civan. Based on the Buckley-Leverett theory, the field production profiles were calculated with and without asphaltene deposition. A decrease in the oil rate and consequently, the decrease in cumulative oil production in the field is expected due to the damage formation by solids. Maintenance of the production level will be facilitated by treating the nearwellbore with aromatic solvents and maintaining the reservoir pressure above the asphaltene onset pressure

Particle-particle particle-mesh method for dipolar interactions:on error estimates and efficiency of schemes with analytical differentiation and mesh interlacing

The interlaced and non-interlaced versions of the dipolar particle-particle particle-mesh (P3M) method implemented using the analytic differentiation scheme (AD-P3M) are presented together with their respective error estimates for the calculation of the forces, torques, and energies. Expressions for the optimized lattice Green functions, and for the Madelung self-forces, self-torques and self-energies are given. The applicability of the theoretical error estimates are thoroughly tested and confirmed in several numerical examples. Our results show that the accuracy of the calculations can be improved substantially when the approximate (mesh computed) Madelung self-interactions are subtracted. Furthermore, we show that the interlaced dipolar AD-P3M method delivers a significantly higher accuracy (which corresponds approximately to using a twice finer mesh) than the conventional method, allowing thereby to reduce the mesh size with respect to the non-interlaced version for a given accuracy. In addition, we present similar expressions for the dipolar ik-differentiation interlaced scheme, and we perform a comparison with the AD interlaced scheme. Rough tests for the relative speed of the dipolar P3M method using ik-differentiation and the interlaced/non-interlaced AD schemes show that when FFT computing time is the bottleneck, usually when working at high precisions, the interlaced AD-scheme can be several times faster than the other two schemes. For calculations with a low accuracy requirement, the interlaced version can perform worse than the ik and the non-interlaced AD schemes.All authors are grateful to the DAAD organization for providing financial support. C.H. thanks the DFG for support through the SimTech center of excellence, the ScaFaCoS collaboration, and the SFB 716, and acknowledges helpful discussions with A. Arnold and M. Pippig.Peer reviewe

Комплекс мероприятий по повышению противопожарной безопасности в образовательных учреждениях

В статье рассматривается весь комплекс организационных и планирующих мероприятий по проведению пожарной защиты в образовательных учреждениях России. порядок работы руководителей образовательных организаций по обеспечению безопасной жизнедеятельности учащихся и персонала.The article considers the whole complex of organizational and planning measures for conducting fire protection in educational institutions of Russia. the order of work of heads of educational organizations to ensure the safe functioning of students and staff