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.
The electron correlation for inter-shells (1s 2p), (1s 3p) and (1s 3d) was described by the inter-particle radial distribution function f(r12). It was evaluated for Li-atom in the different excited states (1s2 2p), (1s2 3p) and (1s2 3d) using Hartree-Fock approximation (HF). The inter particle expectation values for these shells were also evaluated. The calculations were performed using Mathcad 14 program.
Background: Although studies regarding the role of religious beliefs in psychological well being are relatively recent, the importance of people’s religiousness and spirituality for their health status has been widely acclaimed based on hundreds of published studies.
Patients and Methods: The Arabic Modified version of WHOQOL-SRPB (World health organization quality of life-spirituality, religiosity and personal belief) questionnaire was self
administered to a systematic random sample of 100 fifth year medical students.
Results: Around a quarter (21-28%) of subjects perceived religiousness as very to extremely important. This percentage raised to 38% for spirituality and further to 61% for personal believes.
The Ciliophoran Trichodina magna Van As and Basson, 1989 is recorded for the first time in in Iraq from gills of the blue tilapia Oreochromis aureus (Steindachner, 1864) Iraq from Al-Graiat location on the Tigris River at Baghdad city. The description and measurements of this external parasite as well as its illustrations are given.
The aim of the research is to measure the relationship and effect of the application of total production maintenance TPM in the operational strategy, as it is considered one of the most important strategies for the process of restoring production losses because of inefficient equipment. Competitive edge in the global market by upgrading the operational strategies of OS in the application of TPM in those institutions that apply both H-OS-oriented and P-OS-oriented strategies where the strategy has been identified as a critical success factor. The aim of this study is to attempt to consider the application of comprehensive productive maintenance in industrial establishments
Aннотация
В статье представлены явления полисемии и омонимии в специализированной терминосистеме, а именно в геодезической терминологии; определены предпосылки и причины возникновения полисемии и омонимии в профессиональном языке в области геодезии и кадастра; установлены различия и взаимосвязь между понятиями омонимия и полисемия; выделены главных типы полисемантических тер
... Show MoreObjective(s): The present study aims at assessing the prevalence of smoking among health workers in Baghdad Teaching Hospital and to find out the effectiveness of instructional booklet concerning risk of smoking on health workers′ knowledge in hospital.
Methodology: A pre-experimental design study was conducted from 1st of October 2019 to 17th of March 2020. A non-probability sample consists of (500) participant (343 non-smokers and 157 smokers) from (1500) health workers in Baghdad Teaching Hospital, they included the physicians, nurses, pharmacists, physiotherapists, Laboratory Technicians, Medical Assistants. A questionnaire is constructed to evaluate the effectiveness of instructional booklet on health workers’ knowledge
The present study aimed to estimate percentage of red and white muscles fibers in two species of bony fishes belong to two different families which represented by Tenualosa ilisha (Hamilton , 1822) that belongs to the family Clupeidae and Cyprinus carpio (Linnaeus , 1758) that belongs to the family Cyprinidae . The samples were collected from local market at holy Karbala province. The results show difference clear in mean values of muscles numbers at different studied length groups, and the percentage of red muscles fibers were less than that of white muscle fibers at different body regions (R1,R2,and R3) among species. The total average of red muscle fibers values ranged between (4.23 - 11.08 %) while the total average of wh
... Show MoreBack ground: Chronic total occlusion (CTO) of coronary arteries remains one of the most challenging lesion subsets in interventional cardiology even with the development of medical devices and operator expertise. Successful revascularization results in improved in angina status ,increased exercise capacity and reduces the need for lat CABG surgery .
Objectives: This study sought to determine the overall procedural success rate of percutaneous coronary intervention (PCI) for CTOs and to examine the relation between variables such as; patients’ characteristics, risk factors, lesion characteristics and procedural success rate.
Methods: In this study ,clinical and coronary angiography data of (80) patients with CTO who underwent PCI
In this study, Titanium Dioxide Nanoparticles were synthesized by an easy and eco-friendly technique (green synthesis) using green tea leaves (Camillia sinensis), Nanoparticles were analyzed using structural and optical analysis, the X-ray pattern showed that Titanium Dioxide NPs had a tetragonal structure with (Face Centered Tetragonal) FCT crystal structure, the UV-visible recorded an absorbance peak near 350 nm and calculated energy band gap was 3.5 eV, all measurements were proved the purity and Nano size of prepared Nanoparticles. Biochemical parameters evaluation also mentioned in this research, these analyzes showed that Titanium Dioxide nanoparticles in particular dose (50 mg/kg) have the ability to reduce blood glucose
... Show MoreThe 8 - mixing ratios of 7 - transitions from levels of 26 Mg populated in 23 Na (a, py)26Mg reaction are calculated using a2 — ratio method for the first time in the case of two mixed y - transitions from the same initial level. The results obtained have been compared with 8 - values determined by other methods. The comparison shows that the agreement is excellent. This confirms the validity of this method in calculating the 6 - values of such 7 - transitions.