The Effect of Shadowing on Initial Conditions, Transverse Energy and Hard Probes in Ultrarelativistic Heavy Ion Collisions

The effect of shadowing on the early state of ultrarelativistic heavy ion collisions is investigated along with transverse energy and hard process production, specifically Drell-Yan, $J/\psi$, and $\Upsilon$ production. We choose several parton distributions and parameterizations of nuclear shadowing, as well as the spatial dependence of shadowing, to study the influence of shadowing on relevant observables. Results are presented for Au+Au collisions at $\sqrt{s_{NN}} = 200$ GeV and Pb+Pb collisions at $\sqrt{s_{NN}} = 5.5$ TeV.Comment: Submitted to Phys. Rev.

Heavy Quark Photoproduction in Ultra-peripheral Heavy Ion Collisions

Heavy quarks are copiously produced in ultra-peripheral heavy ion collisions. In the strong electromagnetic fields, c c-bar and b b-bar are produced by photonuclear and two-photon interactions; hadroproduction can occur in grazing interactions. We present the total cross sections, quark transverse momentum and rapidity distributions, as well as the Q Q-bar invariant mass spectra from the three production channels. We consider AA and pA collisions at the Relativistic Heavy Ion Collider and Large Hadron Collider. We discuss techniques for separating the three processes and describe how the AA to pA production ratios might be measured accurately enough to study nuclear shadowing.Comment: Minor changes to satisfy referees and typo fixes; 52 pages including 17 figure

Nontrivial dependence of dielectric stiffness and SHG on dc bias in relaxors and dipole glasses

Dielectric permittivity and Second Harmonic Generation (SHG) studies in the field-cooled mode show a linear dependence of dielectric stiffness (inverse dielectric permittivity) on dc bias in PMN-PT crystals and SHG intensity in KTaO$_{3}$:Li at small Li concentrations. We explain this unusual result in the framework of a theory of transverse, hydrodynamic-type, instability of local polarization.Comment: 5 figure

Hard Parton Rescatterings and Minijets in Nuclear Collisions at LHC

The average number of minijets and the corresponding transverse energy produced in heavy ion collisions are evaluated by including explicitly semi-hard parton rescatterings in the dynamics of the interaction. At the LHC semi-hard rescatterings have a sizable effect on global characteristics of the typical inelastic event. An interesting feature is that the dependence on the cutoff which separates soft and hard parton interactions becomes less critical after taking rescatterings into account.Comment: 14 pages, 3 figures. Enlarged discussion in sect.1 and 4; 1 figure added. To be published in Phys.Rev.

Hard X-ray Bursts Recorded by the IBIS Telescope of the INTEGRAL Observatory in 2003-2009

To find X-ray bursts from sources within the field of view of the IBIS/INTEGRAL telescope, we have analysed all the archival data of the telescope available at the time of writing the paper (the observations from January 2003 to April 2009). We have detected 834 hard (15-25 keV) X-ray bursts, 239 of which were simultaneously recorded by the JEM-X/INTEGRAL telescope in the standard X-ray energy range. More than 70% of all bursts (587 events) have been recorded from the well-known X-ray burster GX 354-0. We have found upper limits on the distances to their sources by assuming that the Eddington luminosity limit was reached at the brightness maximum of the brightest bursts.Comment: 18 pages, 2 figures, 2 table

Вычисление живучести транспортных машин

The article deals with multi criteria problem of the mechanical system in case of destruction of some of its elements. As an example, a dynamic contact between the gas-turbine locomotive GT1-h with an obstacle is considered. The purpose of this work is to obtain the information about the limit state of the locomotive cabin in terms of the parameters of the obstacles and the speed of the locomotive movement. This information is necessary for the design calculations, and is presented in a form suitable for engineering analysis. In three-dimensional parameter, space external impacts acting on the cab is defined as a hypersurface, which indicates that the structure is in the limit state. Such a surface determines the survivability of vehicles and specifies the safe operation of the locomotive cab in case of a collision with an obstacle. The calculations conducted have shown a significant effect of the area and location of load on the cabin survivability. It was concluded that it is necessary to strengthen the cabin to ensure the safety of the crew and the dashboard of the cab in case of an emergent collision with the obstacle of large mass and a high speed.Рассматривается многокритериальная задача поведения механической системы при разрушении отдельных элементов. В качестве примера анализируется внештатная ситуация динамического взаимодействия газотурбовоза ГТ1-h с препятствием. Цель работы состоит в получении информации о предельном состоянии кабины локомотива в зависимости от параметров препятствия и скорости движения состава. Данная информация необходима при выполнении проектных расчетов и представлена в виде, удобном для инженерного анализа. В трехмерном пространстве параметров внешнего воздействия на кабину построена поверхность перехода конструкции в предельное состояние. Такая поверхность ограничивает область безопасной эксплуатации кабины при случайном столкновении с препятствием. В результате проведенных расчетов выявлено существенное влияние площади и места приложения нагрузки на несущую способность кабины. Дано заключение о необходимости усиления кабины для обеспечения безопасности экипажа и приборной части при несанкционированной встрече с препятствием значительной массы и нарушении скоростного режима

Вычисление живучести транспортных машин

The article deals with multi criteria problem of the mechanical system in case of destruction of some of its elements. As an example, a dynamic contact between the gas-turbine locomotive GT1-h with an obstacle is considered. The purpose of this work is to obtain the information about the limit state of the locomotive cabin in terms of the parameters of the obstacles and the speed of the locomotive movement. This information is necessary for the design calculations, and is presented in a form suitable for engineering analysis. In three-dimensional parameter, space external impacts acting on the cab is defined as a hypersurface, which indicates that the structure is in the limit state. Such a surface determines the survivability of vehicles and specifies the safe operation of the locomotive cab in case of a collision with an obstacle. The calculations conducted have shown a significant effect of the area and location of load on the cabin survivability. It was concluded that it is necessary to strengthen the cabin to ensure the safety of the crew and the dashboard of the cab in case of an emergent collision with the obstacle of large mass and a high speed.Рассматривается многокритериальная задача поведения механической системы при разрушении отдельных элементов. В качестве примера анализируется внештатная ситуация динамического взаимодействия газотурбовоза ГТ1-h с препятствием. Цель работы состоит в получении информации о предельном состоянии кабины локомотива в зависимости от параметров препятствия и скорости движения состава. Данная информация необходима при выполнении проектных расчетов и представлена в виде, удобном для инженерного анализа. В трехмерном пространстве параметров внешнего воздействия на кабину построена поверхность перехода конструкции в предельное состояние. Такая поверхность ограничивает область безопасной эксплуатации кабины при случайном столкновении с препятствием. В результате проведенных расчетов выявлено существенное влияние площади и места приложения нагрузки на несущую способность кабины. Дано заключение о необходимости усиления кабины для обеспечения безопасности экипажа и приборной части при несанкционированной встрече с препятствием значительной массы и нарушении скоростного режима

Катушечновильчатый высаживающий аппарат для ориентированной посадки лукасевка

Seed onion planting is fundamental operation at realization of technological process of onions cultivation. The main lack of bulb planters is a group picking of bulbs from overall mass by planting devices, but not single-piece wherefore planting of bulbs in demanded orientation is problematic. It was noted that when developing of bulb planters for planting of bulbous cultures it is necessary to provide optimum balance between productivity and quality indicators of planting: uniformity of distribution along a row and quantity of the bulbs with a stem below. It was established that the roller feeds are most perspective. There were defined their main shortcomings: seeds damage and lack of bulbs stem below orientation. Thus, uniformity of distribution makes about 40 percent. A special device with the orienting funnels was suggested. A forked-roller feed for the oriented seed onion planting for the oriented planting of seed onion carrying out single-piece picking of bulbs from the bunker and their giving in seed tube at below stem orientation for planting in a furrow was worked out. Researches confirmed that the suggested design provides stable performance of technological process of bulbs planting.Посадка лука-севка - основополагающая операция при реализации технологического процесса возделывания лука. Основным недостатком машин для посадки лука-севка остается групповой отбор луковиц из общей массы высаживающими аппаратами, а не поштучный, из-за чего посадка луковиц в требуемом положении затруднительна. Отметили, что при разработке высаживающих аппаратов для посадки луковых культур необходимо обеспечить оптимальный баланс между производительностью и качественными показателями посадки (равномерность распределения луковиц вдоль рядка и количество луковиц, посаженных донцем вниз). Установили, что наиболее перспективными являются катушечные высевающие аппараты. Определили их основные недостатки - повреждение семян и отсутствие ориентации луковиц донцем вниз, при этом равномерность распределения составляет около 40 процентов. Предложили ориентирующее устройство - ориентирующие воронки. Разработали катушечно-вильчатый высаживающий аппарат для ориентированной посадки лука-севка, осуществляющий поштучный отбор луковиц из бункера и подачу их в семяпровод донцем вниз для сбрасывания в борозду. Исследования подтвердили, что предложенная конструкция обеспечивает стабильное выполнение технологического процесса по посадке луковиц

Impact-parameter dependent nuclear parton distribution functions: EPS09s and EKS98s and their applications in nuclear hard processes

We determine the spatial (impact parameter) dependence of nuclear parton distribution functions (nPDFs) using the $A$-dependence of the spatially independent (averaged) global fits EPS09 and EKS98. We work under the assumption that the spatial dependence can be formulated as a power series of the nuclear thickness functions $T_A$. To reproduce the $A$-dependence over the entire $x$ range we need terms up to $[T_A]^4$. As an outcome, we release two sets, EPS09s (LO, NLO, error sets) and EKS98s, of spatially dependent nPDFs for public use. We also discuss the implementation of these into the existing calculations. With our results, the centrality dependence of nuclear hard-process observables can be studied consistently with the globally fitted nPDFs for the first time. As an application, we first calculate the LO nuclear modification factor $R^{1jet}_{AA}$ for primary partonic-jet production in different centrality classes in Au+Au collisions at RHIC and Pb+Pb collisions at LHC. Also the corresponding central-to-peripheral ratios $R_{CP}^{1jet}$ are studied. We also calculate the LO and NLO nuclear modification factors for single inclusive neutral pion production, $R_{dAu}^{\pi^0}$, at mid- and forward rapidities in different centrality classes in d+Au collisions at RHIC. In particular, we show that our results are compatible with the PHENIX mid-rapidity data within the overall normalization uncertainties given by the experiment. Finally, we show our predictions for the corresponding modifications $R_{pPb}^{\pi^0}$ in the forthcoming p+Pb collisions at LHC.Comment: 36 page