A noniterative design procedure for supplemental brace-damper systems in single-degree-of-freedom systems

SUMMARY: In this paper, a method for designing supplemental brace-damper systems in single-degree-of-freedom (SDOF) structures is presented. We include the effects of the supporting brace stiffness in the dynamic response by using a viscoelastic Maxwell model. On the basis of the study of an SDOF under ground excitation, we propose a noniterative design procedure for simultaneously specifying both the damper and the brace while assuring a desired structural performance. It is shown that to increase the damper size beyond the value delivered by the proposed criteria will not provide any improvement but actually worsen the structural response. The design method presented here shows excellent agreement with the FEMA 273 design approach but offers solutions closer to optimality. © 2013 John Wiley & Sons, Ltd

Effect of Fly Ash on Properties of Self-Compacting High Strength Lightweight Concrete

As known, fillers directly affect the properties of self-compacting concrete. Fly ash is one of the common fillers used in production of SCC. Using lightweight concrete is extremely important for reducing the self-weight of structures, especially in heavy ones, like high rise buildings. It enables to decrease additional loads in case of renovation or/strengthening of existing structures. Moreover, self-compaction avoids using vibrations for compaction of concrete in existing structures. Therefore the present study is aimed at investigating the effect of change in fly ash content on the properties of self-compacting lightweight concrete (SCLWC). For this reason slump flow test, J-Ring test, L-Box test and V-funnel test were conducted to find workability of the fresh concrete mixture. Further compressive strength, splitting tensile strength, modulus of elasticity and flexural strength of the hardened concrete were obtained. Three concrete mixes of SCLWC with different fly ash contents were prepared to find the best workability and hardened concrete properties. The results of this study form a basis for proportioning of effective concrete mixtures suitable for repairing existing structures and elements

Особенности оценки и нормирования естественной убыли нефтепродуктов в эластичных резервуарах

An effective technique for experimental studies to determine the losses of petroleum products in flexible tanks is suggested. Standards of technological losses of petroleum products on the permeability, swelling and wetting flexible tanks are defined.Разработана эффективная технология проведения экспериментальных исследований по определению потерь нефтепродуктов в эластичных резервуарах. Определены нормы технологических потерь нефтепродуктов от проницаемости, набухания и смачивания оболочки эластичных резервуаров

MATLAB And SiMuLink LABorATory - A BASiS for LeArning reAL conTroL AppLicATionS

Abstract A laboratory for teaching computer programming and engineering concepts related to control applications was recently established in the Department of Electrical Engineering and Electronics at the Ariel University Center of Samaria. The new laboratory provides hands-on experience in the design of control systems used in different fields of engineering. The lab offers an excellent introduction to programming concepts and research concepts that are often troublesome for the undergraduates. This paper describes the general approach and practical application of MATLAB and Simulink in the frame of a laboratory for teaching control. The main aim of the laboratory is to help students gain a deep understanding of typical problems in control applications. Students prepare codes in MATLAB an

Вопросы использования термопластичных рукавов для нефтепродуктов в условиях холодного климата

The possibility of using pressure thermoplastic hoses in the Arctic and the Far North is evaluated. The conclusion that the replacement of rubber hoses on the thermoplastic will reduce 2.5 times their material consumption, extend the 10-15 C temperature range of operating temperatures, eliminate the influence of sleeve material on fuel quality, improve the strength characteristics and terms of use is presented.С температурный диапазон рабочих температур, исключить влияние материала рукава на качество горючего, повысить прочностные характеристики и сроки эксплуатации

Новые подходы к оценке топливостойких полимерных материалов

The basis of the proposed methodology is the evaluation of the barrier and physico-mechanical properties of structural polymeric material after the unilateral oil exposure at the alleged exploitation of the climatic region. Calculation of technical and economic efficiency methodology shows that savings of 360,000 rubles occur when testing the same polymer material with a petroleum product.Основу предлагаемой методологии составляет оценка барьерных и физико-механических характеристик конструкционного полимерного материала после одностороннего воздействия нефтепродукта при температуре предполагаемого климатического района эксплуатации. Расчет технико-экономической эффективности методологии показывает, что экономия составила 360 000 руб. при испытании одного полимерного материала с одним нефтепродуктом

Вопросы оптимизации размеров эластичных резервуаров для полевых складов горючего

The article outlines the theoretical approaches to the optimization of the geometrical parameters of flexible tanks for petroleum products taking into account the total length of the stitches on the top and bottom surfaces. The algorithm, mathematical models and optimization criterion to significantly (up to 20%) increase the efficiency of cutting the material of construction are proposed. On the basis of these curves are the formulas for determining the optimal height, length and width of the flexible container. The calculations are for the optimal sizes for example, flexible container with a capacity of 250 m3.В статье изложены теоретические подходы к вопросам оптимизации геометрических параметров эластичных резервуаров (ЭР) для нефтепродуктов с учётом общей длины швов на верхней и нижней поверхностях. Предложены алгоритм, математические модели и критерий оптимизации, позволяющие существенно (до 20%) повысить эффективность раскроя конструкционного материала. На основе полученных зависимостей приведены формулы для определения оптимальных высоты, длины и ширины эластичных резервуаров. Приведены расчеты оптимальных размеров на примере эластичного резервуара вместимостью 250 м3

Перспективы развития полевых складов горючего

The use of thermoplastic polyurethanes in collapsible tanks design will improve the environmental safety of 2.0-2.5 times, extend the temperature range of operation up to 30%, reduce the effort required to deploy a warehouse in 2.5 - 3.0 times.Исследованы вопросы совершенствования эксплуатационных характеристик полевых складов горючего. Использование термопластичных полиуретанов в конструкции эластичных резервуаров позволит повысить экологическую безопасность в 2,0 - 2,5 раза, расширить температурный диапазон эксплуатации до 30%, снизить трудозатраты на развертывание склада в 2,5 - 3,0 раза. Обоснована критичность технологии производства конструкционных материалов на основе термопластичного полиуретана из отечественного сырья