This paper studies the effect of contact areas on the transient response of mechanical structures. Precisely, it investigates replacing the ordinary beam of a structure by two beams of half the thickness, which are joined by bolts. The response of these beams is controlled by adjusting the tightening of the connecting bolts and hence changing the magnitude of the induced frictional force between the two beams which affect the beams damping capacity. A cantilever of two beams joined together by bolts has been investigated numerically and experimentally. The numerical analysis was performed using ANSYS-Workbench version 17.2. A good agreement between the numerical and experimental results has been obtained. In general, results showed that the two beams vibrate independently when the bolts were loosed and the structure stiffness is about 20 N/m and the damping ratio is about 0.008. With increasing the bolts tightening, the stiffness and the damping ratio of the structure were also increased till they reach their maximum values when the tightening force equals to 8330 N, where the structure now has stiffness equals to 88 N/m and the damping ratio is about 0.062. Beyond this force value, increasing the bolts tightening has no effect on stiffness of the structure while the damping ratio is decreased until it returned to 0.008 when the bolts tightening becomes immense and the beams behave as one beam of double thickness.
Abstract
We produced a study in Estimation for Reliability of the Exponential distribution based on the Bayesian approach. These estimates are derived using Bayesian approaches. In the Bayesian approach, the parameter of the Exponential distribution is assumed to be random variable .we derived bayes estimators of reliability under four types when the prior distribution for the scale parameter of the Exponential distribution is: Inverse Chi-squar
... Show MoreCorruption is one of the barriers to economic growth and investment opportunities, and after the most serious security and stability, that corruption plagued the Iraqi economy is striking and has roots since the eighties of the last century to the present day.
The study aimed to identify practical impact of corruption on investment in the Iraqi economy and revealed the possibilities and obstacles to investment in Iraq and clarify the investment opportunities at the level of Iraq and the impact of corruption on investments.
The focus will be on the statement of the extent of corruption and investment in Iraq and the adoption of the style of economic measurement using cross-section
... Show MoreThe development in the presentation and presentation of the service in order to distinguish them from the same, was one of the most important reasons to choose the current issue to upgrade the level of service, especially in the Iraqi restaurant sector, which has become today of the important sectors successful. The problem of research was to try to answer a range of questions: to what extent are Iraqi restaurants interested in physical service factors? Do Iraqi restaurants apply physical factors in a way that leads to customer satisfaction? Are Iraqi restaurants interested in the satisfaction of their customers? The objective of the current research is to try to determine the extent to which the
... Show MoreHuman values are the most important concepts that the interest of society has to relay on these conceptual values. Any society will not be stabilized unless adheres to the right principles and values, all nations need such principles and values to stabilize. If any society doesn’t implement the human values that monotheistic religions urges equality between human, the far the society from the religious principles, the less there would be valence between human. The valence is urgent necessity in the current time. The far people get away from values and principles, the more they lose their freedom and dignity, therefore individual has to live with dignity and respect through the adherence to these values and principles. Apparently, equal
... Show MoreThe inflammatory bowel disease (IBD), Crohn’s disease (CD) and ulcerative colitis (UC) are heterogenous chronic inflammatory disorders of the gastrointestinal tract. The most widely accepted etiopathogenic hypothesis for these disorders suggests an immune mediated process.
Objective: This study was performed to evaluate the role of interleukine-33 in pathogenesis of inflammatory bowel disease and to correlate their levels with the disease activity and/or severity.
Methods: Fifty five subjects with inflammatory bowel disease (41 ulcerative colitis patients and 14 Crohn’s disease patients) their ages range from 16-65 years and 25 apparently healthy volunteers their ages and sexes were matched with the patients were participated i
Harold Pinter often portrays the dilemma of obliterated figures that are incapable of feeling of their own existences. These figures feel exhausted and frustrated in a world that deprives them their humanity. They retreat into a limited world where they look for security and protection. The characters' feeling of security is threatened by outside forces represented by intruding persons who stand for the mysterious powers that are indefinable. The conflict between these intruders and the characters finally ends with the characters’ defeat. The reason for the intruders' attack on the victims remains ambiguous and is not explained. The element of mystery pervades Pinter's plays and represents one of
... Show MoreIn this work, Soda Lime Glass (S.L.G.) powder was used ,as
fluxe in traditional porcelain instead of feldspar. Two ceramics
porcelain were compared; commercial or traditional porcelain that
content of 50wt % kaolin, 25wt % quartz, and 25wt % feldspar.
Feldspar mass was substituted by scraps soda lime glass yielding a
new porcelain composition, to determine the softening points and
then the effect of glass addition on porcelain firing process.
Eight samples, for each patch, were prepared and 8wt % water
was added. The resulting composite blends were then die pressed at
2N, to produce disk specimens with diameter of 1.5 cm, and then
they were sintered at (1000, 1100, 1200, 1250,1300,1350,1400 and
1450) ˚C,
The road networks is considered to be one of the determinants that controls to specify the areas of human activities, which it depend on to specify the arrival cost , in addition it is useful to achieve the connectivity for interaction and human activities , and shorten the distance and time between the population and places of service. The density of the road network in any space directly affected by the density of population and the type of economic activities and administrative functions performed by the space. On this basis, the subject of this study is reflected in the quantitative analysis of the roads network in the Governorate of Karbala. The study consists the quantitative analysis for the roads network and the Urban Nodes in th
... Show MoreIsmailism is of great importance in Islamic history and Islamic political thought. In different countries of the Muslim world today their presence exists and is active but is confused with mystery and secrecy. The most important characteristic of their political ideology is their dependence on the esoteric exegesis, which they have made an intellectual basis for which their most ideas relate, when they make for everything visible and exposed a hidden matter, not only aware of the esoteric exegesis, which only God knows and entrenched in science, and they mean imams or whoever They are called "(esoteric)" as a result of the Ismaili belief in esoteric interpretation and that everything is apparent inward, as well as they called the ((seven
... Show MoreThe research addresses smart city concept as it is the latest urban design trends, by the investment of the capabilities of human, and artificial intelligence for the sake of the advancement of the city. The concept of a smart city is described as one of the most important manifestations of the information revolution, with the end of the twentieth, and the beginning of twenty – first century, The research attributes the emergence of the concept to: deficiencies of means, and traditional methods in building and development of cities, as well as The significant increase in the number of city and global metropolises dwellers. So, smart city approach has been adopted, along with innovative principles and methods which cons
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