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.
It is well known that drilling fluid is a key parameter for optimizing drilling operations, cleaning the hole, and managing the rig hydraulics and margins of surge and swab pressures. Although the experimental works represent valid and reliable results, they are expensive and time consuming. In contrast, continuous and regular determination of the rheological fluid properties can perform its essential functions during good construction. The aim of this study is to develop empirical models to estimate the drilling mud rheological properties of water-based fluids with less need for lab measurements. This study provides two predictive techniques, multiple regression analysis and artificial neural networks, to determine the rheological
... Show MoreBackground: Pain due to muscular cramp during hemodialysis is one of the most common problems experienced by patient undergoing hemodialysis, and is associated with poor outcomes of patients. The main aim of this study was to comparing the effects of lavender oil and olive oil massage on Pain due to muscular cramp during hemodialysis.
Methods: In this random clinical trial, 60 hemodialysis patients were enrolled randomly and allocated to two groups with 30 members in Lordegan and Brojen hospitals, Shahrekord, Iran. The intervention included flora massage on the lower leg muscles so that the first group received olive oil massage (10 drops) and the second group received lavender oil massage (10 dr
... Show MoreThis work deals with the effect of adding aluminum nanoparticles on the mechanical properties, micro-hardness and porosity of memory-shape alloys (Cu-Al-Ni). These alloys have wide applications in various industrial fields such as (high damping compounds and self-lubricating applications). The samples are manufactured using the powder metallurgy method, which involved pressing in only one direction and sintered in a furnace surrounded by an inert gas. Four percentages (0%, 5%, 10%, and 15%) of aluminum nanoparticles were fabricated, which depended on the weight of aluminum powder (13%) in the sample under study. To find out which phase is responsible for the reliability of the formation of this type of alloy and its porosity, X-ray diffr
... Show MoreIntroduction: Although it is discouraged, community pharmacy customers can obtain oral corticosteroids (OCSs) without prescriptions from some community pharmacies in Iraq. Medication abuse is defined as the use of medication for non-medical reasons. Objectives: The study aimed to determine demographics, beliefs, and perceptions associated with the abuse of oral corticosteroids for non-illness reasons among community pharmacy customers. Methods: This cross-sectional study was conducted in fall 2018 in four provinces in Iraq. Customers of 19 community pharmacies asking for OCSs for themselves without a prescription were administered a paper survey. This study used the Theory of Reasoned Action (TRA) to measure the relation
... Show MoreThe basis of the personality of each individual lies in the early years of his or her life. If the personality of the child has been well organized and if the motives have been fully expressed and effectively directed, the child will have a strong will, happy self-confidence and a strong personality. If there is a failure In the early years, the individual will be unable to meet his responsibilities in life and may be the victim of many psychological disorders. The family is a learning process through which children acquire the customs, traditions, attitudes and values prevailing in their social environment. (Pre-and-after) play and its relationship to parenting methods of (democratic-bullying-overprotection- and neglect), which wi
... Show MoreTax state institution regards as one of the largest state institutions implementing the tax rules issuing be legislative body and achieving the goals of tax (financial, economic, social and political). So, the tax management should pay attention to the procedures enabling it to achieve those rules starting from the procedures of tax restrict and ending by tax allocation where the process of assessment the taxation must relaxing on modern methods. The problem of the study raising from that in spite of there is a low obliging the taxable person (registered or not) to submit a declaration about his income and the achieved profit to be the base of taxation˒ where the other ways are secondary ways helping in rejection of t
... Show MoreThe Present study aims at answering the following questions:
1-What is the level of the teaching style of biology teachers who teach (human and his
health)
2-what is the level of healthy attitude to the teachers of biology who teach (human and his
health).
3- is there any relation between the teaching style of biology teachers who teach (human and
his health)and their student's Ability Mind.
4- is the any relation between the level of the healthy attitude to the teachers of biology who
teach (human and his health).
The researcher made the following for the purpose of answering the question of the study:
1-The card of observing the level of the teaching style (lecture style )to the teachers of
biology
The research aims to achieve market share requirements and reach the targeted competitive price through the application of management accounting techniques represented by continuous improvement technique and target costing under an Activity Based Cost (ABC) system and Activity Based Management (ABM), In Muthanna Cement Company to reach the rationalization of the cost of the product and maintain the required quality and improve the profitability of the company.
The problem of research has emerged in the inability of local firms to enter into effective competition with other companies operating in the same economic sector, Because of the high cost of its products, Which led to the sale of the product at prices below its cost, and t
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