Spherical gearing with intermediate ball elements: parameter ranges with a high contact ratio

The paper presents analytical research of the geometry and kinematical parameters of spherical gearing with ball intermediate elements. The main attention is paid to the influence of the offset coefficient on the tooth geometry generation, the contact ratio and the motion transmission angle. Intermediate ball element racetracks on the gear are trochoidal curves on a spherical surface. Two areas for the offset coefficient values providing a high value of the contact ratio – basic trochoid (without offset) and prolate trochoid with abutting racetracks of adjacent ball elements ― were revealed. Analysis of the investigated parameters showed that for power transmission, it is preferable to use spherical gearing without an offset, and for kinematic transmission, it is possible to use profiles with a large offset. The present study allows making a rational choice of geometrical parameters depending on the transmission predestination

ПОРІВНЯЛЬНИЙ АНАЛІЗ МЕТОДІВ ВІДНОВЛЕННЯ ПРОПУЩЕНИХ ДАНИХ ЧАСУ ДОСТУПНОСТІ СЕРВЕРА В ІНФОРМАЦІЙНО- EКОНОМІЧНИХ ПРОСТОРАХ

In the article presents results of research of primary statistical characteristics of time of processing and data transmission are given in systems of information economic area. On the basis of the received results the analysis of methods of recovery of the passed data is made. In work methods of data processing with admissions are analyzed and the most rational are chosen. Change of the law of distribution of selection depending on a way of elimination of the passed data is investigated. Forecasting of time of availability of the server of information economic area is executed. The goal of this paper is primary statistical characteristics research of data processing and transmission time in IES. Particularly, the server availability time (SAT) was studied within this work. This time consists of Client-to-Server connection time, Server data processing time, and Server answer transfer time. The values of service time were taken for research, that were received while studying of cloud computing performance. It was established that if data loss is not over 6% distribution law of initial model selection saves. If data loss is between 9% and 15% methods primary statistical characteristics of studied selection were determined without consideration of data missing. Missed data was filled with data distributed by the same law as for initial selection with admissions.В статье приведены результаты исследования первичных статистических характеристик времени обработки и передачи данных в информационно-экономических пространствах. На основании полученных результатов выполнен  анализ методов восстановления пропущенных данных. В работе проанализированы приемы обработки данных с пропускам и выбраны наиболее рациональные. Исследовано изменение  закона распределения выборки в зависимости от способа устранения пропущенных данных. Выполнено прогнозирование времени доступности сервера в информационно-экономических пространствах. Цель работы состояла в исследование первичных статистических характеристик времени обработки и передачи данных в информационно-экономических пространствах.  В частности, в рамках данной работы изучалось время доступности сервера.У статті наведено  результати дослідження первинних статистичних характеристик часу обробки і передачі даних в інформаційно-економічних просторах. На підставі отриманих результатів виконано  аналіз методів відновлення пропущених даних. Проаналізовано прийоми обробки даних з пропускам та  обрано найбільш раціональні. Досліджена зміна  закону розподілу вибірки залежно від способу усунення пропущених  даних.  Виконано прогнозування часу доступності сервера економічних просторів. Мета роботи полягала у дослідження первинних статистичних характеристик часу обробки і передачі даних в інформаційно-економічних просторах. Зокрема, в рамках даної роботи вивчалося час доступності сервера

The study of the effect of aluminum powders dispersion on the oxidation and kinetic characteristics

Differential-scanning calorimetry (DSC) and thermogravimetric analysis (TG) were used to study micro-sized aluminum powder ASD-4 and nano-sized powder Alex. The dependence of the oxidation process on the dispersion of the sample particles is shown. The influence of thermogravimetric conditions on the thermal regime of the process was considered, and its kinetic parameters were determined. Calculations of the activation energy and the pre-exponential factor were carried out

The Equivalence Theorem in Effective Theories

The famous equivalence theorem is reexamined in order to make it applicable to the case of intrinsically quantum infinite-component effective theories. We slightly modify the formulation of this theorem and prove it basing on the notion of generating functional for Green functions. This allows one to trace (directly in terms of graphs) the mutual cancelation of different groups of contributions.Comment: 21 pages, 7 figures; v2: Section 4 is modified, plus minor corrections in other sections, version accepted for publication in PR

Metal-insulator transition induced by 16O -18O oxygen isotope exchange in colossal negative magnetoresistance manganites

The effect of 16O-18O isotope exchange on the electric resistivity was studied for (La(1-y)Pr(y))0.7Ca0.3MnO3 ceramic samples. Depending on y, this mixed perovskite exhibited different types of low-temperature behavior ranging from ferromagnetic metal (FM) to charge ordered (CO) antiferromagnetic insulator. It was found that at y=0.75, the substitution of 16O by 18O results in the reversible transition from a FM to a CO insulator at zero magnetic field. The applied magnetic field (H >= 2 T) transformed the sample with 18O again to the metallic state and caused the increase in the FM transition temperature Tc of the 16O sample. As a result, the isotope shift of Tc at H = 2 T was as high as 63 K. Such unique sensitivity of the system to oxygen isotope exchange, giving rise even to the metal-insulator transition, is discussed in terms of the isotope dependence of the effective electron bandwidth which shifts the balance between the CO and FM phases.Comment: 5 pages (RevTeX), 2 eps figures included, to appear in J. Appl. Phys. 83, (1998