Dislocation loops in overheated free-standing smectic films

Static and dynamic phenomena in overheated free-standing smectic-A films are studied using a generalization of de Gennes' theory for a confined presmectic liquid. A static application is to determine the profile of the film meniscus and the meniscus contact angle, the results being compared with those of a recent study employing de Gennes' original theory. The dynamical generalization of the theory is based on on a time-dependent Ginzburg-Landau approach. This is used to compare two modes for layer-thinning transitions in overheated films, namely "uniform thinning" vs. nucleation of dislocation loops. Properties such as the line tension and velocity of a moving dislocation line are evaluated self-consistently by the theory.Comment: 16 pages, 8 figure

ЭЛЕКТРОМАГНИТНЫЙ МОНИТОРИНГ В АФТЕРШОКОВЫЙ ПЕРИОД ЧУЙСКОГО ЗЕМЛЕТРЯСЕНИЯ 2003 г. В ГОРНОМ АЛТАЕ: МЕТОДИКА ИЗМЕРЕНИЙ, РЕЗУЛЬТАТЫ

The article considers the method of observations, interpretation of data and results of electromagnetic monitoring with a controlled source for one of the seismically active regions of Siberia – Mountain (Gorny) Altai. The monitoring is carried out during the aftershock period in the epicentral zone of the destructive Chuya earthquake of 2003 with M=7.3. For regular observations, a measurement technique has been developed with several modifications of the transient electromagnetics method (TEM) to determine variations in electrical resistivity and anisotropy coefficient. The long-term series of these two geoelectric parameters of the section are presented, compared with the characteristics of the ongoing seismic events. The analysis shows that variations in electrical resistance and electrical anisotropy reflect the development and gradual attenuation of aftershock activity of a powerful earthquake. The advantages of the TEM method and the chosen methodology for monitoring in complex areas are reflected.В статье рассмотрена методика наблюдений, интерпретации данных и результаты электромагнитного мониторинга с контролируемым источником для одного из сейсмоактивных регионов Сибири – Горного Алтая. Мониторинг выполняется в афтершоковый период в эпицентральной зоне разрушительного Чуйского землетрясения 2003 г. с М=7.3. Для регулярных наблюдений разработана методика измерений несколькими модификациями метода зондирования становлением электромагнитного поля (ЗСБ) для определения вариаций удельного электрического сопротивления и коэффициента анизотропии. Приведены многолетние ряды этих двух геоэлектрических параметров разреза, сопоставленные с характеристиками происходящих сейсмических событий. В результате анализа показано, что вариации электросопротивления и коэффициента электрической анизотропии отражают развитие и постепенное затухание афтершоковой активности мощного землетрясения. Отражены преимущества метода ЗСБ и выбранной методики для мониторинга в сложно построенных районах

BCFL logging: an approach to acquire and preserve admissible digital forensics evidence in cloud ecosystem

Log files are the primary source of recording users, applications and protocols, activities in the cloud ecosystem. Cloud forensic investigators can use log evidence to ascertain when, why and how a cyber adversary or an insider compromised a system by establishing the crime scene and reconstructing how the incident occurred. However, digital evidence acquisition in a cloud ecosystem is complicated and proven difficult, even with modern forensic acquisition toolkit. The multi-tenancy, Geo-location and Service-Level Agreement have added another layer of complexity in acquiring digital log evidence from a cloud ecosystem. In order to mitigate these complexities of evidence acquisition in the cloud ecosystem, we need a framework that can forensically maintain the trustworthiness and integrity of log evidence. In this paper, we design and implement a Blockchain Cloud Forensic Logging (BCFL) framework, using a Design Science Research Methodological (DSRM) approach. BCFL operates primarily in four stages: (1) Process transaction logs using Blockchain distributed ledger technology (DLT). (2) Use a Blockchain smart contract to maintain the integrity of logs and establish a clear chain of custody. (3) Validate all transaction logs. (4) Maintain transaction log immutability. BCFL will also enhance and strengthen compliance with the European Union (EU) General Data Protection Regulation (GDPR). The results from our single case study will demonstrate that BCFL will mitigate the challenges and complexities faced by digital forensics investigators in acquiring admissible digital evidence from the cloud ecosystem. Furthermore, an instantaneous performance monitoring of the proposed Blockchain cloud forensic logging framework was evaluated. BCFL will ensure trustworthiness, integrity, authenticity and non-repudiation of the log evidence in the cloud

ВАРИАЦИИ ЭЛЕКТРОФИЗИЧЕСКИХ ПАРАМЕТРОВ ПО ДАННЫМ ЭЛЕКТРОМАГНИТНОГО МОНИТОРИНГА КАК ИНДИКАТОР АКТИВНОСТИ РАЗЛОМНЫХ ЗОН

In the regions of high seismic activity, investigations of fault zones are of paramount importance as such zones can generate seismicity. A top task in the regional studies is determining the rates of activity from the data obtained by geoelectrical methods, especially considering the data on the faults covered by sediments. From a practical standpoint, the results of these studies are important for seismic zoning and forecasting of natural and anthropogenic geodynamic phenomena that may potentially occur in the populated areas and zones allocated for construction of industrial and civil objects, pipelines, roads, bridges, etc. Seismic activity in Gorny Altai is regularly monitored after the destructive 2003 Chuya earthquake (M=7.3) by the non-stationary electromagnetic sounding with galvanic and inductive sources of three modifications. From the long-term measurements that started in 2007 and continue in the present, electrical resistivity and electrical anisotropy are determined. Our study aimed to estimate the variations of these electrophysical parameters in the zone influenced by the fault, consider the intensity of the variations in comparison with seismicity indicators, and attempt at determining the degree of activity of the faults. Based on the results of our research, we propose a technique for measuring and interpreting the data sets obtained by a complex of non-stationary sounding modifications. The technique ensures a more precise evaluation of the electrophysical parameters. It is concluded that the electric anisotropy coefficient can be effectively used to characterize the current seismicity, and its maximum variations, being observed in the zone influenced by the fault, are characteristic of the fault activity. The use of two electrophysical parameters enhances the informativeness of the study.В регионах с высокой сейсмической активностью повышенный интерес к исследованию разломных зон связан с тем, что они могут являться сейсмогенерирующими, поэтому определение степени их активности с помощью методов геоэлектрики является актуальной задачей, особенно для нарушений, перекрытых осадочными отложениями.  С практической точки зрения эти исследования важны для задач сейсморайонирования, прогнозирования возможных природных и техногенных геодинамических явлений в заселенных районах, при строительстве промышленных и гражданских объектов, газопроводов, дорог, мостов и т.д. Регулярные наблюдения в сейсмоактивной зоне Горного Алтая после разрушительного Чуйского землетрясения 2003 г. с М=7.3 выполняются методами нестационарного электромагнитного зондирования с использованием трех модификаций с гальваническими и индуктивными источниками. Для анализа многолетних измерений, которые были начаты в 2007 г. и продолжаются по настоящее время, привлечены два электрофизических параметра – удельное электрическое сопротивление и коэффициент электрической анизотропии. Целью работы является оценка вариаций этих параметров в зоне влияния разлома, сопоставление их интенсивности с показателями сейсмичности, что дает возможность определить степень активности выявленных разломных нарушений. В результате исследования предложена методика измерений и интерпретации данных комплекса модификаций нестационарного зондирования, с помощью которой можно наиболее точно оценить значения электрофизических параметров. Вывод заключается в том, что коэффициент электрической анизотропии может быть эффективно использован для характеристики текущей сейсмичности, а его максимальные вариации, которые наблюдаются в зоне влияния разлома, характеризуют его активность. Использование двух электрофизических параметров увеличивает информативность исследования

Molecular simulation of chevrons in confined smectic liquid crystals

Chevron structures adopted by confined smectic liquid crystals are investigated via molecular dynamics simulations of the Gay-Berne model. The chevrons are formed by quenching nematic films confined between aligning planar substrates whose easy axes have opposing azimuthal components. When the substrates are perfectly smooth, the chevron formed migrates rapidly towards one of the confining walls to yield a tilted layer structure. However, when substrate roughness is included, by introducing a small-amplitude modulation to the particle- substrate interaction well-depth, a symmetric chevron is formed which remains stable over sufficiently long runtimes for detailed structural information, such as the relevant order parameters and director orien- tation, to be determined. For both smooth and rough boundaries, the smectic order parameter remains non-zero across the entire chevron, implying that layer identity is maintained across the chevron tip. Also, when the surface-stabilised chevron does eventually revert to a tilted layer structure, it does so via surface slippage, such that layer integrity is maintained throughout the chevron to tilted layer relaxation process. </p

MAGNETIC PROPERTIES OF RAPIDLY QUENCHED Sm-Fe-V ALLOYS

This work about magnetic hysteresis properties of a Sm-Fe-V amorphus ribbons obtained by spin coating was investigated. It was found that at the optimum annealing temperature (850 °C), the coercive force value was 6,9 kOe, which makes it possible to obtain a sintered permanent magnet in the future.Исследование выполнено за счет гранта Российского научного фонда (проект № 21-72-10104)

INFLUENCE OF THE COMPOSITION OF A LOW-MELTING ADDITIVE ON THE MAGNETIC HYSTERESIS PROPERTIES OF Nd-Fe-B NANOCRYSTALLINE ALLOYS AFTER INFILTRATION

In this work the influence of infiltration of low-melting additives on the magnetic hysteresis properties of a nanocrystalline alloy based of the compound Nd-Fe-B was investigated. It was found that additives R-Cu-Co (R = Gd, Ce, and La) lead to an increase in the coercivity from 30% to 40%.Исследование выполнено за счет гранта Российского научного фонда (проект № 21-72-10104)

VARIATIONS IN ELECTROPHYSICAL PARAMETERS ESTIMATED FROM ELECTROMAGNETIC MONITORING DATA AS AN INDICATOR OF FAULT ACTIVITY

In the regions of high seismic activity, investigations of fault zones are of paramount importance as such zones can generate seismicity. A top task in the regional studies is determining the rates of activity from the data obtained by geoelectrical methods, especially considering the data on the faults covered by sediments. From a practical standpoint, the results of these studies are important for seismic zoning and forecasting of natural and anthropogenic geodynamic phenomena that may potentially occur in the populated areas and zones allocated for construction of industrial and civil objects, pipelines, roads, bridges, etc. Seismic activity in Gorny Altai is regularly monitored after the destructive 2003 Chuya earthquake (M=7.3) by the non-stationary electromagnetic sounding with galvanic and inductive sources of three modifications. From the long-term measurements that started in 2007 and continue in the present, electrical resistivity and electrical anisotropy are determined. Our study aimed to estimate the variations of these electrophysical parameters in the zone influenced by the fault, consider the intensity of the variations in comparison with seismicity indicators, and attempt at determining the degree of activity of the faults. Based on the results of our research, we propose a technique for measuring and interpreting the data sets obtained by a complex of non-stationary sounding modifications. The technique ensures a more precise evaluation of the electrophysical parameters. It is concluded that the electric anisotropy coefficient can be effectively used to characterize the current seismicity, and its maximum variations, being observed in the zone influenced by the fault, are characteristic of the fault activity. The use of two electrophysical parameters enhances the informativeness of the study

Applied Crystallography On the instrumental resolution in X-ray reflectivity experiments

A general method to describe the instrumental resolution function for grazingangle X-ray scattering experiments is presented. A resolution function R is introduced as the Gaussian joint-distribution function of the (interdependent) random deviation q H associated with the wavevector transfer q. Useful expressions for the mean square values of q H are derived for some common scattering geometries, such as rocking scans, and scans out of the plane of incidence. The mean square values related to the incident beam dispersion and the detector acceptance angles are included in the treatment of R. As an example, R is incorporated in the calculation of the diffuse scattering from freestanding smectic ®lms within the framework of the ®rst Born approximation and the main resolution effects are discussed