Passive damping concepts for slender columns in space structures

An experimental and theoretical study of three different passive damping concepts is conducted for a slender member with partial rotational end restraints. Over a hundred full-scale natural vibration experiments were conducted to evaluate the effectiveness of mass-string, polyethylene tubing, and chain damping concepts. The damping properties obtained from the experiments were used in the approximate analyses based on the partial differential equation of motion for the problem. The comparison of the experimental and the theoretical deflection-time relations shows that the velocity-dependent damping model used in the theory is adequate. From the experimental results, the effect of end connection friction and induced axial forces on damping is identified. The definition of an efficiency index is proposed based on the damping ratio and the mass of a given passive damping device. Using this definition, the efficiencies of the three damping devices are compared. The polyethylene tubing concept resulted into a low damping efficiency

Household Electrosmog

Electromagnetic wave energy is prevalent in the environment and is generated by numerous sources. This invisible electromagnetic wave/radiation pollution is termed Electrosmog. When exposed to this electromagnetic energy, health effects in humans have been observed and subsequent standards for emission have been set. A common household appliance that generates this energy is the microwave oven. This study evaluates the intensity of electromagnetic radiation leakage from microwave ovens subject to standard exposure levels and the possibility of biological effects at levels below the standards. We have taken the exposure levels into account in an effort to generate comparisons between microwave ovens according to their age. These comparisons have allowed us to create awareness of the possibility of harmful levels of electromagnetic radiation in our homes.

Passive damping concepts for tubular beams with partial rotational and translational end restraints

The main objectives of the study are: (1) identification of potential passive damping concepts for slender tubular structural members with rotational and translational end springs under natural and forced-free vibrations; (2) evaluation of damping efficiencies of the various damping concepts; and (3) evaluation of the suitability of a theoretical finite difference analysis by comparison to the experimental results for the case of natural vibrations. Only member flexural an translation motion is considered. The natural vibration study is conducted on the seven damping concepts and for only one specific initial deflection. The most suitable of the seven dampers is further investigated under forced-free vibrations. In addition only one set of end springs is used for all of the experiments. The results show that passive damping provides a possible approach to structural vibration reduction

The DNA Of Materials

Introductory physics labs provide many challenging yet applicable experiments and concepts to the many fields of engineering.  One such lab has been developed at West Virginia University that explores resistivities of several different materials and ties this concept into electrical engineering practices and standards.  Many students do not realize that resistivity is a very significant quantity that contributes greatly to the understanding of natural as well as man-made materials; it is the DNA of materials. This lab provides engineering students an opportunity to not only learn physics of materials, but to also gain real-world experience and understanding of why certain materials are used in electronic devices and when designing and constructing buildings.  This lab has been implemented in several introductory lab levels here at West Virginia University, and all have been met with enthusiasm and strong participation.  In our pre-engineering physics course, this has been especially effective, as it has given the students some hands-on experience with physics principles that they will make use of in their future careers

Detection P53, Rb1 and H-ras Loss of Heterozygosity LOH in Patients with Urinary Bladder carcinoma

In this study 22 samples of urine sediments were obtained from patients with Urinary Bladder Carcinoma, DNA base technique and LOH detection was investigated in three genes P53, Rb1 and H-ras. The result are shown that LOH was present in most cases and for all genes where LOH in P53 represents (31.8%) and for Rb1 (45.4%) and for H-ras gene (27.2%).In some cases, more than one gene locus mutations were found

Bacteriological and immunological study associated with patients of Urinary Bladder carcinoma

The blood, serum & urine samples are collected from (22) patients with urinary bladder cancer were admitted to Al-Hilla general teaching hospital after diagnosis by helping urology physician. The result appeared that E.coli with high percentage (22.7% ,27.2%)in nixed &single infection respectively followed by Ps.aeuroginosa (22.7% , 13.6%) and S.aureus (18.8% , 9.09%).   Interleukin 2 &Interleukin 8 concentration level was detected in serum by enzyme-linked immunosorbent assay(ELISA) and data were compared with control to compare the performance of each cytokins & results show no elevated , no significant decrease in level  in two cytokins, this leads  to an independent factors for the detection of urinary bladder cancer

Studying the Physical Properties of Hma with Recycled Aggregate Subjected to Moisture

تصنع الخلطات الاسفلتية الحارة HMA  من مواد معينة ذات حساسية لوجود المياه في التبليط الاسفلتي الذي يمنع العجينة من الالتصاق بالركام . ولكون العجينة هي الغراء الذي تمسك الخلطة مع بعضها , لذا فان  الفشل الانشائي المتوقع بالتبليط سيكون سريع من جراء ضعف الالتصاق بين العجينة والركام او ما يسمى بالانفصال  stripping الذي يوجب استخدام مضافات معينة لتجنبه ك الجير المطفأ او أي مواد كيمياوية مضادة للانفصال anti-stripping.  وعليه اجريت هذه الدراسة لفحص وقياس مقاومة انواع مختلفة من الخلطات الاسفلتية ذات ركام معاد تدويره عند تعريضها لفترات تشبع بالرطوبة بالإضافة الى فحص مغزى استخدام المضادات للانفصال كمضافات . تم  في هذا البحث تعريض ثلاثة انواع من الخلطات الاسفلتية , واحدة 60% من ركامها معاد من خلطة اسفلتية واخرى 60% من ركامها معاد من خلطة خرسانية  والخلطة الثالثة مستخدمة الشمع كمضاف وبنسبة 10% من وزن الاسفلت , للتغريق بالماء بمدد مختلفة تمثلت ب( 3, 7, 15, 28 ) يوم , كما  اجريت فحوصات مختبرية متعددة عليها ومقارنة النتائج مع خلطة اسفلتية قياسية عرضت لنفس الظروف . تم اجراء( فحص مارشال للثبات والزحف ), الكثافة , مقاومة الشد الغير مباشرة , مقاومة الانضغاط ، فحص التحسس للحرارة , فحص قوة المرونة . كان التحري موفقا حيث اعطى نتائج قيمة تبين تحسن الخلطة الاسفلتية في مقاومتها للرطوبة عند استخدام ركام معاد من خلطات سابقة واثبات دور الشمع الفعال في زيادة تللك المقاومة وتحسين خواص الخلطة الاسفلتية.As being exposed to water that exists on asphalt road, HMA that is created by utilizing a certain resources may require to be made strong due to the capability of that water to stop the covering to be attached to the aggregate, consequently, asphalt road layers will not be held jointly, this will have a negative influence on the asphalt that will be damaged quickly. Such phenomenon is known as "the erosion", which requires to be dealt with by, for example, improving asphalt layers by means of specific resources that assist in existence of water. Different ways in this work are employed to calculate the strength of various mixes via using used aggregate that is exposed to  saturation times, similarly, the importance of exploiting the anti-stripping as chemical addition is determined. Three kinds of HMA were exposed in the current study, 60% of the first kind were made of used aggregate taking from crushed pavement, and 60% of the second kind were taking from using aggregate that is part of concrete mix, while the third mixture has 10% of wax used as an addition by pavement weight. These mixtures were soaked in water bath of 25o C for various intervals of time that are (3, 7, 15, 28) days. Many investigations examinations had been as well executed, and then the outcomes were contrasted against standard pavement blend subjected to similar circumstances. Number of examinations were adopted in this study, these are (Marshall Stability and flow), mass thickness, roundabout elasticity, compressive quality, affectability to temperature, flexible modulus. The study achieved a good success as it makes important outcomes, the enhanced pavement showed strength against moisture damage while taking advantage of used aggregate of preceding blends, on other hand, the wax has affective role in raising these strengths in addition to develop the characteristics of HMA.&nbsp

Carotid Doppler ultrasonography in young stroke patients

Background: The present study focuses on the role of carotid doppler ultrasonography (CDUS) in the diagnosis and management of carotid stenosis in young stroke patients. Methods: The findings of carotid doppler in 45 ischemic stroke patients between 15-45 years of age were reviewed retrospectively. The variables of interest for this study included risk factors for atherosclerotic disease, primary abnormality detected on carotid doppler ultrasonography (ulceration vs. stenosis), degree of stenosis and the type of plaque (soft vs. calcified). Results: The prevalence of hypertension and diabetes was 50% and 35% respectively. The rate of carotid stenosis in the study population was found to be 31%. The degree of stenosis was mild in 35% and moderate in 21%. High-grade stenosis was found in 21% of patients. The plaque was soft in the majority of cases (43%). CONCLUSION: The proportion of carotid stenosis in young stroke patients was relatively high compared with previous studies. This may be due to an increase in the risk factors for atherosclerotic disease in developing countries