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:
Typological analysis about the negation marker in different languages is one of the fields of research that has attracted much attention. In Persian language, this constituent has been analysed from different aspects. This study aimed to analyse different aspects of negation marker in the adjectives, the noun phrases and the verb phrases based on typological analysis. Many studies have been revealed that the negation in adjectives has shown lexically and morphologically. In the noun phrases, /hich/ has used as a negative marker necessarily marking the verb phrase as negative too. In the verb phrases, negation occurs morphologically by the addition of the prefix /n
... Show MoreA literary-educational work is a work that explains wisdom to the reader and presents moral, educational and instructional issues in a literary form. Qaboos-nameh or Nasihat al-Muluk is an educational and educational book that has a special place in the field of ethics and guidance, where the author guides his children. Also, Ibn al-Wardi's Lamiyah or Nasihat al-Akhwan is a poem containing moral advice and advice in 77 verses that Ibn al-Wardi wrote to his son.
It seems that the main goal of Ibn al-Wardi and Onsur AL-maali in Lamia and Qaboos-nameh was to express educational and moral issues and spread and convey them to future generations. Ibn al-Wardi, like Onsur AL-maali, listed moral points such as knowledge, humility
... Show Moreيعتبر "تاج الأشواك" أو نبات شوكة المسيح، وهو من نباتات الزينة الطبية ، ينتمي إلى جنس يوفوربيا. E. milii يحتوي كميات وفيرة من المركبات الفينولية ، التربينات، الستيرويدات والقلويدات. كانت الأهداف الرئيسية لهذه الدراسة هي فحص مستخلصات الفلافونويد والنانو فلافونويد ضد نوعين من خطوط الخلايا السرطانية. تم تصنيع مركبات الفلافونويد النانوية عن طريق تفاعل مركب الكيتوسان والماليك اسد. تم تحليل مركبات الفلافونويد ال
... Show MoreThe present research included synthesis of silver nanoparticle from(1*10-3,1*10-4 and1*10-5) M aqueous AgNO3 solution through the extract of M.parviflora reducing agent. In the process of synthesizing silver nanoparticles we detected a rapid reduction of silver ions leading to the formation of stable crystalline silver nanoparticles in the solution.
Insulin like growth factor-1 has metabolic and growth-related roles all over the body and is strongly associated and regulated by growth hormone. It is produced by almost any type of tissue, especially the liver. The study aimed to measure insulin like growth factor in growth hormone deficient patients and find its relation with other studied parameters. The Subjects in the study were 180 studied in the National Diabetic Center for Treatment and Research/Al-Mustansiriya University in Baghdad/Iraq for the period from November 2021 to April 2022. Blood was drawn and investigated for the levels of IGF-1, IGFBP-3, LH, and FSH. Also testosterone and statistical analysis was carried out to find the potential correlations. The results relived t
... Show MoreA new, simple, accurate, fast and sensitive spectrophotometric method has been developed for the analysis of amiloride in pure and pharmaceutical formulations by continuous flow injection analysis. The method was based on the oxidation of the drug with Ce(IV)sulfate in acidic medium to formed a pinkish-red color species which determined using homemade Ayah 3SBGR x3-3D solar cell flow injection photometer. Optimum conditions were obtained using a high intensity green light emitted diode as a source. The linear dynamic range for the instrument response versus amiloride concentration was 0.0005- 10 mmol.L-1 while the L.O.D was of 9.471 ng / sample. The correlation coefficient (r) was 0.9824 while percentage linearity (r2%) was 96.50%. RSD%
... Show MoreThe research aims to develop physical exercises with auxiliary training tools that work to develop the explosive power of the arms and legs, and then find out their effect on the accuracy of shooting from free throw and correction from jumping of advanced basketball players, as the researchers found a problem that these players have weakness in the skill of throwing Free throwing and shooting by jumping calculated with two points as a result of adopting unhealthy physical and technical positions, which led to a lack of focus and accuracy, and thus negatively affected the performance technique of free throw and jump shot, as most teams use traditional exercises without the use of auxiliary training tools, and this topic gave researchers the
... Show MoreThe relationship between F2- layer critical frequencies (foF2), total sunspot number (Ri), northern hemisphere sunspot number (Rn) and southern hemisphere sunspot number (Rs) at station located in mid- latitudes on latitude near to latitude of Iraq (Rome station, lat.: 42o N and lon.: 13o E) and for 2003(the descending phase of solar cycle 23) were studied.
This research work aims to know the correlation range between them, through correlation coefficients which correlate between them, and hence, the dependence on that index for predicting F2- layer critical frequencies. When the correlation coefficients between foF2, Ri, Rn and Rs were compared for different seasons of 2003, It is found that, correlation coefficient between foF2 and
В статье рассматривается вопрос об использовании мультимедийных средств для оптимизации процесса формирования коммуникативной компетенции в иракской аудитории с привлечением компьютерных технологий. Статья посвящена использованию мультимедийных технологий и различных приемов формирования интереса к русскому языку. Включение в процесс обучения коммуникативно-значимого, аутентичн
... Show MoreThe research seeks to clarify the problems related to the aspects of the financial and accounting process resulting from entering into contractual arrangements with a period of more than 20 years, among which is the research problem represented by the lack of clarity of the foundations and procedures for the recognition of oil costs and additional costs borne by foreign invested companies, which led to a weakening of their credibility and reflection. Negatively "on the measurement and accounting disclosure of financial reports prepared by oil companies, and the research aims to lay down sound procedures for measuring and classifying oil costs and additional costs paid to foreign companies, and recognizing and recording them in th
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