Stresses in Twisted Cylindrical Plugs of Non-homogeneous Material Inserted into a Rigid Medium

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ADAPTIVE SUBOPTIMAL CONTROL OF INPUT CONSTRAINED PLANTS

This paper deals with adaptive regulation of a discrete-time linear time-invariant plant with arbitrary bounded disturbances whose control input is constrained to lie within certain limits. The adaptive control algorithm exploits the one-step-ahead control strategy and the gradient projection type estimation procedure using the modified dead zone. The convergence property of the estimation algorithm is shown to be ensured. The sufficient conditions guaranteeing the global asymptotical stability and simultaneously the suboptimality of the closed-loop systems are derived. Numerical examples and simulations are presented to support the theoretical result

ADAPTIVE SUBOPTIMAL CONTROL OF INPUT CONSTRAINED PLANTS

This paper deals with adaptive regulation of a discrete-time linear time-invariant plant with arbitrary bounded disturbances whose control input is constrained to lie within certain limits. The adaptive control algorithm exploits the one-step-ahead control strategy and the gradient projection type estimation procedure using the modified dead zone. The convergence property of the estimation algorithm is shown to be ensured. The sufficient conditions guaranteeing the global asymptotical stability and simultaneously the suboptimality of the closed-loop systems are derived. Numerical examples and simulations are presented to support the theoretical result

Angular momentum dependent friction slows down rotational relaxation under non-equilibrium conditions

It has recently been shown that relaxation of the rotational energy of hot non-equlibrium photofragments (i) slows down significantly with the increase of their initial rotational temperature and (ii) differs dramatically from the relaxation of the equilibrium rotational energy correlation function, manifesting thereby breakdown of the linear response description [Science 311, 1907 (2006)]. We demonstrate that this phenomenon may be caused by the angular momentum dependence of rotational friction. We have developed the generalized Fokker-Planck equation whose rotational friction depends upon angular momentum algebraically. The calculated rotational correlation functions correspond well to their counterparts obtained via molecular dynamics simulations in a broad range of initial non-equilibrium conditions. It is suggested that the angular momentum dependence of friction should be taken into account while describing rotational relaxation far from equilibrium

Intelligent Programm Support for Dynamic Integrated Expert Systems Construction

AbstractThe problems of intellectualization in the development process of integrated expert systems basing on the the problem-oriented methodology and the AT-TECHNOLOGY workbench are considered. The automation of dynamic integrated expert systems construciton is in focus. The intellgient programm environment and its basic components, including standard design procedure are reviewed. The detailed description of procedure for dynamic integrated expert system construction is given. The examples of applied integrated expert system prototypes developed with described procedure are listed

Pulse Shape Analysis and Identification of Multipoint Events in a Large-Volume Proportional Counter in an Experimental Search for 2K Capture Kr-78

A pulse shape analysis algorithm and a method for suppressing the noise component of signals from a large copper proportional counter in the experiment aimed at searching for 2K capture of Kr-78 are described. These signals correspond to a compound event with different numbers of charge clusters due to from primary ionization is formed by these signals. A technique for separating single- and multipoint events and determining the charge in individual clusters is presented. Using the Daubechies wavelets in multiresolutional signal analysis, it is possible to increase the sensitivity and the resolution in extraction of multipoint events in the detector by a factor of 3-4.Comment: 10 pages, 8 figures. submitted to Instruments and Experimental Techniques; ISSN 0020/441

The pseudo-spin symmetry in Zr and Sn isotopes from the proton drip line to the neutron drip line

Based on the Relativistic continuum Hartree-Bogoliubov (RCHB) theory, the pseudo-spin approximation in exotic nuclei is investigated in Zr and Sn isotopes from the proton drip line to the neutron drip line. The quality of the pseudo-spin approximation is shown to be connected with the competition between the centrifugal barrier (CB) and the pseudo-spin orbital potential (PSOP). The PSOP depends on the derivative of the difference between the scalar and vector potentials $dV/dr$. If $dV/dr = 0$, the pseudo-spin symmetry is exact. The pseudo-spin symmetry is found to be a good approximation for normal nuclei and to become much better for exotic nuclei with highly diffuse potential, which have $dV/dr \sim 0$. The energy splitting of the pseudo-spin partners is smaller for orbitals near the Fermi surface (even in the continuum) than the deeply bound orbitals. The lower components of the Dirac wave functions for the pseudo-spin partners are very similar and almost equal in magnitude.Comment: 22 pages, 9figure

Многослойные углеродные нанотрубки – компонент энергоемких суспензионных реактивных горючих

Objectives. The addition of high-density carbon materials to jet fuels can lead to a significant increase in the volumetric energy of the fuel combustion. The purpose of the current study was to thermodynamically analyze the possibility of obtaining model hydrocarbon fuels from toluene and T-1 using stacked-cup multiwall carbon nanotubes (MWCNTs). Methods. Bomb combustion calorimetry was used to define the combustion energy of the MWCNTs in the crystalline state. The temperature dependence of the MWCNTs’ heat capacity in the range 5–370 K and the fusion parameters were estimated using low-temperature adiabatic calorimetry. The physical density of MWCNTs was measured using the pycnometric method. The sedimentation stability of the mixtures of MWCNTs with liquids was determined using centrifugation at 7000 g. The calculations were carried out in MS Excel. Results. The energy and enthalpy of combustion of a technical sample of MWCNTs in the crystalline state were determined. Based on the smoothed heat capacity values, the standard thermodynamic functions (enthalpy, entropy, and Gibbs reduced energy) of MWCNTs in the crystalline state were obtained in a temperature range of 0–2000 K. The extrapolation of the MWCNTs’ heat capacity was carried out at a temperature of up to 2000 K using the heat capacity of crystalline graphite. It has been established that mixtures of MWCNTs with liquids containing more than 33 mass % of MWCNTs are stable during centrifugal sedimentation at 7000 g. For the toluene–MWCNTs and fuel T-1–MWCNTs model systems, the specific and volumetric combustion energies, the adiabatic combustion temperatures, and the conditional final maximum speed of the model rockets with fuel of various compositions were also calculated. Conclusions. The thermodynamic analysis showed that the addition of MWCNTs can significantly increase the volumetric energy intensity of traditional jet fuels, which can in turn improve the operational characteristics of drones and rockets. Цели. Добавление высокоплотных углеродных материалов в реактивные топлива может привести к значительному увеличению его объемной энергоемкости. Цель работы заключалась в проведении термодинамического анализа возможности получения модельных углеводородных топлив из толуола и Т-1 с многослойными углеродными нанотрубками (МУНТ). Методы. Свойства МУНТ были исследованы при помощи следующих методов: энергия сгорания в кристаллическом состоянии определена методом бомбовой калориметрии, температурная зависимость теплоемкости в интервале 5–370 K – методом адиабатической калориметрии, физическая плотность – пикнометрическим методом, седиментационная устойчивость смесей с жидкостями – центрифугированием при 7000 g. Расчеты проводились в программе MS Excel. Результаты. Определены энергия и энтальпия сгорания технического образца МУНТ в кристаллическом состоянии. На основании сглаженных значений теплоемкости получены стандартные термодинамические функции (энтальпия, энтропия и приведенная энергия Гиббса) МУНТ в кристаллическом состоянии в интервале 0–2000 K. Экстраполяция теплоемкости МУНТ до температуры 2000 K проведена с использованием теплоемкости кристаллического графита. Установлено, что смеси МУНТ с жидкостями, содержащими МУНТ более 33 масс. %, седиментационно устойчивы в центрифуге при 7000 g. Для модельных систем толуол–МУНТ, горючее Т-1–МУНТ вычислены массовые и объемные энергии сгорания, адиабатические температуры горения, условная конечная максимальная скорость модельных ракет с горючим различных составов. Выводы. Термодинамический анализ показал, что добавление МУНТ существенно повышает объемную энергоемкость традиционных реактивных топлив, что должно приводить к улучшению эксплуатационных характеристик летательных аппаратов.

Test of Nuclear Wave Functions for Pseudospin Symmetry

Using the fact that pseudospin is an approximate symmetry of the Dirac Hamiltonian with realistic scalar and vector mean fields, we derive the wave functions of the pseudospin partners of eigenstates of a realistic Dirac Hamiltonian and compare these wave functions with the wave functions of the Dirac eigenstates.Comment: 11 pages, 4 figures, minor changes in text and figures to conform with PRL requirement

Distribution and abundance of western gray whales off northeastern Sakhalin Island, Russia, 2001’003

In 2001’003, >60,000 km of aerial surveys and 7,700 km of vessel surveys were conducted during June to November when critically endangered Korean–Okhotsk or western gray whales (Eschrichtius robustus) were present off the northeast coast of Sakhalin Island, Russia. Results of surveys in all years indicated gray whales occurred in predominantly two areas, (1) adjacent to Piltun Bay, and (2) offshore from Chayvo Bay, hereafter referred to as the Piltun and offshore feeding areas. In the Piltun feeding area, the majority of whales were observed in waters shallower than 20 m and were distributed from several hundred meters to ∼ 5 km from the shoreline. In the offshore feeding area during all years, the distribution of gray whales extended from southwest to northeast in waters 30’5 m in depth. During all years, the distribution and abundance of whales changed in both the Piltun and offshore feeding areas, and both north–south and inshore–offshore movements were documented within and between feeding seasons. The discovery of a significant number of whales feeding in the offshore area each year was a substantial finding of this study and raises questions regarding western gray whale abundance and population levels, feeding behavior and ecology, and individual site-fidelity. Fluctuations in the number of whales observed within the Piltun and offshore feeding areas and few sightings outside of these two areas indicate that gray whales move between the Piltun and offshore feeding areas during their summer–fall feeding season. Seasonal shifts in the distribution and abundance of gray whales between and within both the Piltun and offshore feeding areas are thought, in part, to be a response to seasonal changes in the distribution and abundance of prey. However, the mechanism driving the movements of whales along the northeast coast of Sakhalin Island is likely very complex and influenced by a multitude of factors