Monte Carlo simulations of the classical two-dimensional discrete frustrated ϕ4\phi ^4 model

The classical two-dimensional discrete frustrated $\phi ^4$ model is studied by Monte Carlo simulations. The correlation function is obtained for two values of a parameter $d$ that determines the frustration in the model. The ground state is a ferro-phase for $d=-0.35$ and a commensurate phase with period N=6 for $d=-0.45$. Mean field predicts that at higher temperature the system enters a para-phase via an incommensurate state, in both cases. Monte Carlo data for $d=-0.45$ show two phase transitions with a floating-incommensurate phase between them. The phase transition at higher temperature is of the Kosterlitz-Thouless type. Analysis of the data for $d=-0.35$ shows only a single phase transition between the floating-fluid phase and the ferro-phase within the numerical error.Comment: 5 figures, submitted to the European Physical Journal

Correlated adatom trimer on metal surface: A continuous time quantum Monte Carlo study

The problem of three interacting Kondo impurities is solved within a numerically exact continuous time quantum Monte Carlo scheme. A suppression of the Kondo resonance by interatomic exchange interactions for different cluster geometries is investigated. It is shown that a drastic difference between the Heisenberg and Ising cases appears for antiferromagnetically coupled adatoms. The effects of magnetic frustrations in the adatom trimer are investigated, and possible connections with available experimental data are discussed.Comment: 4 pages, 4 figure

Continuous Time Quantum Monte Carlo method for fermions

We present numerically exact continuous-time Quantum Monte Carlo algorithm for fermions with a general non-local in space-time interaction. The new determinantal grand-canonical scheme is based on a stochastic series expansion for the partition function in the interaction representation. The method is particularly applicable for multi-band time-dependent correlations since it does not invoke the Hubbard-Stratonovich transformation. The test calculations for exactly solvable models as well results for the Green function and for the time-dependent susceptibility of the multi-band super-symmetric model with a spin-flip interaction are discussed.Comment: 10 pages, 7 Figure

Estimation of the fatigue life of steel on the basis of nonlinear model of damage accumulation

В работе приводится сравнительный анализ расчетных методов оценки долговечности стали на основе линейной и нелинейной гипотез суммирования повреждений при случайном внешнем нагружении по нормальному закону распределения, аппроксимированном блоковой нагрузкой

Дозы облучения персонала и населения при нормальной эксплуатации пунктов захоронения радиоактивных отходов

This paper focuses on occupational and public exposure during operation of disposal facilities receiving liquid and solid radioactive waste of various classes and provides a comparative analysis of the relevant doses: actual and calculated at the design stage. Occupational and public exposure study presented in this paper covers normal operations of a radioactive waste disposal facility receiving waste. Results: Analysis of individual and collective occupational doses was performed based on data collected during operation of near-surface disposal facilities for short-lived intermediate-, lowand very low-level waste in France, as well as nearsurface disposal facilities for long-lived waste in Russia. Further analysis of occupational and public doses calculated at the design stage was completed covering a near-surface disposal facility in Belgium and deep disposal facilities in the United Kingdom and the Nizhne-Kansk rock massive (Russia). The results show that engineering and technical solutions enable almost complete elimination of internal occupational exposure, whereas external exposure doses would fall within the range of values typical for a basic nuclear facility. Conclusion: radioactive waste disposal facilities being developed, constructed and operated meet the safety requirements effective in the Russian Federation and consistent with relevant international recommendations. It has been found that individual occupational exposure doses commensurate with those received by personnel of similar facilities abroad. Furthermore, according to the forecasts, mean individual doses for personnel during radioactive waste disposal would be an order of magnitude lower than the dose limit of 20 mSv/year. As for the public exposure, during normal operation, potential impact is virtually impossible by delaminating boundaries of a nuclear facility sanitary protection zone inside which the disposal facility is located and can be solely attributed to the use of public roads during radioactive waste transportation to the disposal facility site. Цель работы – сравнительный анализ фактических и оцениваемых на этапе проектирования доз облучения персонала и населения при захоронении жидких радиоактивных отходов и твердых радиоактивных отходов различных классов. В рамках настоящей статьи рассматривается вариант облучения персонала и населения при нормальной эксплуатации пункта захоронения радиоактивных отходов в режиме размещения отходов. Результаты: выполнен анализ индивидуальных и коллективных доз облучения персонала при приповерхностном захоронении короткоживущих среднеактивных, низкоактивных и очень низкоактивных радиоактивных отходов во Франции, а также при приповерхностном захоронении долгоживущих радиоактивных отходов в России. Проведен анализ проектных оценок доз облучения персонала и населения для объекта приповерхностной изоляции радиоактивных отходов, планируемого к сооружению в Бельгии, а также проектируемых объектов глубинного захоронения в Великобритании и Нижнеканском массиве (Российская Федерация). Техническими и технологическими решениями удается практически полностью исключить внутреннее облучение персонала, а дозы внешнего облучения ограничить диапазоном, характерным и для базовых ядерных технологий. Заключение: планируемые к сооружению, сооружаемые и эксплуатируемые пункты захоронения удаляемых радиоактивных отходов соответствуют действующим в России требованиям безопасности, согласующимся с международными рекомендациями. Оценено, что индивидуальные дозы облучения персонала сопоставимы с данными контроля персонала аналогичных объектов в других странах. Средние индивидуальные дозы облучения персонала при захоронении радиоактивных отходов прогнозируются на порядок ниже установленного предела дозы – 20 мЗв/год. Воздействие на население при нормальной эксплуатации практически исключено установлением санитарно-защитной зоны объекта использования атомной энергии, на которой размещена установка по захоронению отходов, и возможно только при транспортировке радиоактивных отходов по дорогам общего пользования к месту расположения пункта захоронения радиоактивных отходов.

Self-Control of Traffic Lights and Vehicle Flows in Urban Road Networks

Based on fluid-dynamic and many-particle (car-following) simulations of traffic flows in (urban) networks, we study the problem of coordinating incompatible traffic flows at intersections. Inspired by the observation of self-organized oscillations of pedestrian flows at bottlenecks [D. Helbing and P. Moln\'ar, Phys. Eev. E 51 (1995) 4282--4286], we propose a self-organization approach to traffic light control. The problem can be treated as multi-agent problem with interactions between vehicles and traffic lights. Specifically, our approach assumes a priority-based control of traffic lights by the vehicle flows themselves, taking into account short-sighted anticipation of vehicle flows and platoons. The considered local interactions lead to emergent coordination patterns such as ``green waves'' and achieve an efficient, decentralized traffic light control. While the proposed self-control adapts flexibly to local flow conditions and often leads to non-cyclical switching patterns with changing service sequences of different traffic flows, an almost periodic service may evolve under certain conditions and suggests the existence of a spontaneous synchronization of traffic lights despite the varying delays due to variable vehicle queues and travel times. The self-organized traffic light control is based on an optimization and a stabilization rule, each of which performs poorly at high utilizations of the road network, while their proper combination reaches a superior performance. The result is a considerable reduction not only in the average travel times, but also of their variation. Similar control approaches could be applied to the coordination of logistic and production processes

Viral pathogens in urological diseases

Tis review describes different virus taxa that are more prevalent in some variants of urological pathology. Te search of articles was conducted in the information portals of Te Cochrane Database, MEDLINE / PubMed Database, eLIBRARY, ClinicalKey for the period 2008-2018. As a result, the most current and representative studies, containing an interpretation of the dynamics of opinions indicating the involvement of viruses in various urological diseases were selected. Te bacterial component is the most studied in the etiology and pathogenesis of inflammatory diseases, but the viral component, as a rule, remains outside the scope of routine examination of patients, which stagnates conducting of adequate therapy and prevention of infectious and inflammatory diseases in urology