How one can introduce compliance into computer models of the multibody dynamics using features of object-oriented modeling

Dynamics of a multibody system is simulated in a most universal way in case of contacts having a compliance property. This latter case is implemented usually by elasticity / viscosity along the direction normal to the rigid body outer / inner surface and by friction along its tangent direction. The Hertz model is one of the most popular elastic contact models for engineering applications. Object-oriented approach for building up the multibody dynam-ics model simulating compliant contacts is under development in this paper. A technology for constructing classes-templates is applied to build up contact objects in the dynamical model. The Hertz contact model is under consideration as a simplest example

Contact types hierarchy and its object-oriented implementation

Technology of the object-oriented implementation for the multibody dynamics models is the key feature when developing the corresponding computer structures. We are based on an approach originating from concepts explained earlier. Following the guidelines outlined there one can develop the family of the constraint abstractions being adapted to any type of the machinery applications and relatively easily implement corresponding family of Modelica models. One also can reorder these classes hierarchically using sequences of the behaviour inheritance. Solutions concerning contact problems and corresponding examples are under consideration

The kinematics and chemical stratification of the Type Ia supernova remnant 0519-69.0

We present an analysis of the XMM-Newton and Chandra X-ray data of the young Type Ia supernova remnant 0519-69.0 in the Large Magellanic Cloud. We used data from both the Chandra ACIS and XMM-Newton EPIC-MOS instruments, and high resolution X-ray spectra obtained with the XMM-Newton Reflection Grating Spectrometer. The Chandra data show that there is a radial stratification of oxygen, intermediate mass elements and iron, with the emission from more massive elements more toward the center. Using a deprojection technique we measure a forward shock radius of 4.0(3) pc and a reverse shock radius of 2.7(4) pc. We took the observed stratification of the shocked ejecta into account in the modeling of the X-ray spectra with multi-component NEI models, with the components corresponding to layers dominated by one or two elements. An additional component was added in order to represent the ISM, which mostly contributed to the continuum emission. This model fits the data well, and was also employed to characterize the spectra of distinct regions extracted from the Chandra data. From our spectral analysis we find that the fractional masses of shocked ejecta for the most abundant elements are: M(O)=32%, M(Si/S)=7%/5%, M(Ar+Ca)=1%, and M(Fe) = 55%. From the continuum component we derive a circumstellar density of nH= 2.4(2)/cm^3. This density, together with the measurements of the forward and reverse shock radii suggest an age of 450+/-200 yr,somewhat lower than, but consistent with the estimate based on the optical light echo (600+/-200 yr). From the RGS spectra we measured a Doppler broadening of sigma=1873+/-50 km/s, from implying a forward shock velocity of vS = 2770+/-500 km/s. We discuss the results in the context of single degenerate explosion models, using semi-analytical and numerical modeling, and compare the characteristics of 0519-69.0 with those of other Type Ia supernova remnants.Comment: Astronomy and Astrophysics in press. This version is the A&A accepted version, which contains improved figures and an extended discussion sectio

Управління ризиками інфокомунікаційної мережі при стратегічному плануванні безпеки систем критичної інраструктури

The subject matter of the article is information and communication networks of critical infrastructure systems. The goal of the work is to create an approach for strategic managing the security of critical infrastructure systems taking into account the risks of the information and communication network. The article deals with the following tasks: determining the procedure of strategic managing the security of critical infrastructure systems, identifying the risks of the information and communication network, assessing the importance and probability of partial network risks. The following methods are used: a systematic approach, cause-and-effect analysis, statistical methods. The following results are obtained: the diagram of multi-level risk management of critical infrastructure systems is developed; the diagram of the step-by-step method of information risks management is developed for increasing the safety of the system; the complex index is suggested for determining the category of information system security; probable variants of the full-factor environment of a set of values of the complex index elements and the corresponding categories of information systems security are analyzed; the process of adaptation of the system as an integral part of the selection and specification of measures for the risk reduction of the information and communication network is determined; the example of the risk assessment of the information and communication network for a software and hardware complex in the automated control system of technological processes is considered. Taking into account the categories of factors, a list of probable risks of the information and communication network and factors that cause them is given; the cause-and-effect diagram of "cause-risk-effect" interaction is created; the total effect of each factor on the final vertices of the diagram, that is possible effects, is calculated; the factors were grouped as the most important, quite important, of mean importance, and inconsiderable ones.Предметом дослідження в статті є інфокомунікаційні мережі систем критичної інфраструктури. Мета роботи – створення підходу для стратегічного управління безпекою систем критичної інфраструктури з урахуванням ризиків інфокомунікаційної мережі. В статті вирішуються наступні завдання: визначення процедури стратегічного управління безпекою систем критичної інфраструктури, ідентифікація ризиків інфокомунікаційної мережі, оцінка важливості та ймовірності часткових ризиків мережі. Використовуються такі методи: системний підхід, причинно-наслідковий аналіз, статистичні методи. Отримано наступні результати: Побудовано схему багаторівневого управління ризиками систем критичної інфраструктури. Розроблено схему покрокового методу управління інформаційними ризиками для підвищення безпеки системи. Запропоновано комплексний показник для визначення категорії безпеки інформаційної системи. Проаналізовано можливі варіанти повного факторного простору множини значень елементів комплексного показника і відповідні їм категорії безпеки інформаційних систем. Визначено процес адаптації системи як невід'ємну частину вибору і специфікації заходів щодо парирування ризиків інфокомунікаційної мережі. Розглянуто приклад оцінки ризику інфокомунікаційної мережі для програмно-технічного комплексу у складі автоматизованої системи управління технологічними процесами. З урахуванням категорій факторів наведено перелік можливих ризиків інфокомунікаційної мережі із зазначенням причин їх виникнення. Побудовано причинно-наслідкову діаграму взаємодії "причини-ризики-наслідки". Розраховано загальний вплив кожного фактора на кінцеві вершини діаграми – можливі наслідки. Було класифіковано фактори на чотири групи: найбільш важливі, досить значні, середньої значущості, незначні

Fukushima plutonium effect and blow-up regimes in neutron-multiplying media

It is shown that the capture and fission cross-sections of 238U and 239Pu increase with temperature within 1000-3000 K range, in contrast to those of 235U, that under certain conditions may lead to the so-called blow-up modes, stimulating the anomalous neutron flux and nuclear fuel temperature growth. Some features of the blow-up regimes in neutron-multiplying media are discussed.Comment: 15 pages, 8 figures. (v2: numerous corrections and style improvements). arXiv admin note: substantial text overlap with arXiv:1207.369

The Message Design Logics of Responses to HIV Disclosures

This article uses the theory of message design logics to investigate the relative sophistication of responses to disclosure of HIV status. In Study 1, 548 college students imagined a sibling revealing an HIV-positive diagnosis. Their responses to the HIV disclosures were coded as expressive (n= 174), conventional (n= 298), or rhetorical (n= 66). Type of message produced was associated with gender and HIV aversion. In Study 2, 459 individuals living with HIV rated response messages that were taken verbatim from Study 1. Expressive messages were rated lowest in quality, and rhetorical messages were rated highest. The discussion focuses on the utility of message design logics for understanding responses to HIV disclosures and the implications for message design logics