Search

One of the most recent innovations of high-rise tabular structural system is diagrid structure. Diagrid structural system has been widely applied to high-rise buildings at the last two decades. Diagrid system is predominating other types of tabular structural systems because of its structural efficiency and aesthetic potential. To examine the efficiency of diagrid system as lateral load resisting system, a comparative study on the behavior of diagrid system with framed tube system, has been conducted under earthquake action. Three-dimensional finite element models for a reinforced concrete diagrid building and a concrete framed tube building of 36 stories with similar plan configuration and characteristics were performed. The only variation between the two systems is the exterior lateral load resisting scheme. Dynamic response spectrum analysis was utilized to investigate the dynamic behavior for both diagrid and the framed tube system. Findings which include modal results, lateral story displacements, story drifts, story shears and story moments were presented and discussed. The results revealed that diagrid system is more effective as lateral load resisting structure than the framed tube system with a reduction of 21 % of the consumed materials يعتبر نظام الشبکة القطرية الإنشائي أحد أحدث الأنظمة الإنشائية للمباني العالية وأکثرها أنشارا. يمتاز نظام الشبکة القطرية عن باقي الأنظمة الأنبوبية المشهورة کفائتة الإنشائية للأحمال الجانبية الناتجة من الزلازل أو أحمال الرياح وأيضا بشکله المعماري المتميز. لاختبار کفاءة نظام الشبکة القطرية في تحمل الأحمال الجانية تم عمل دراسة مقارنة بين هذا النظام ونظام الإطار الأنبوبي. تم عمل نمذجة ثلاثية الأبعاد للنظامين بأبعاد متماثلة وبارتفاع 36 دور لکلا النظامين وتم التأثير بحمل ديناميکي (زلزالي). أوضحت النتائج أن نظام الشبکة القطرية أن کفاءته أعلي لمقاومة الحمل الزلزالي من مقاومة نظام الإطار الأنبوبي.

The demand for high speed trains has significantly been increasing globally for the past two decades. High speed trains have great impact on bridges. Therefore, investigation of bridge performance under moving trains with high speeds is crucial. In this paper, the behavior of concrete railway tied arch bridge under moving loads is presented. Numerical study through detailed three-dimensional finite element models were developed to examine the dynamic characteristics behavior of railway tied arch bridges. Three railway concrete tied arch bridges with span lengths of 36 m, 50 m and 60 m were nominated for the study. The dynamic parameters that influence the dynamic response which include; the number of coaches, damping, and train speeds were considered. Dynamic characteristics behaviors, such as mode shapes, dynamic amplification factor, resonance and its cancellation phenomenon were evaluated. Subsequently, both resonance and cancellation speeds were determined, and the optimal bridge span length that suppresses the response at resonance was also proposed.

Tied arch bridges, among other types of arch bridges, are the most delightful bridges that have been ever shaped on the earth. Analysis and design of tied arch bridge is further intricate especially when the bridge is skewed. In this research paper, the behavior of skewed concrete tied arch bridge is presented. Numerical investigation through three-dimensional finite element models was performed to examine the behavior of skewed concrete tied arch bridge. The study involved five concrete tied arch bridges with five different span lengths of 30, 35, 40, 45, and 50 m, and different skew angles ranging from 0°-to-60°. Linear static analysis was conducted for the nominated bridges. The effect of skew angle, and the aspect ratio (span length/width), on the response of the global and the main supporting structural elements and on the deck flooring system of the bridge was examined. The results showed that an increase of the skew angle will alter the bridge behavior. Deflections, reactions, and straining actions of the main supporting elements and floor system were significantly influenced when the skew angle increased.

Nano-devices operating inside the human body enabled many new applications in the healthcare domain. Communication between nano-devices is a crucial task that aids the rising new applications in thriving. Unfortunately, in-vivo medium contains biomaterials and fluids, e.g., blood, that contaminate the THz signal. In this paper we investigate the effect of the Red Blood Cells (RBCs) concentration (i.e. hematocrit) in blood on its dielectric and optical properties. We present an electromagnetic model for blood with the flexibility of specifying the volume fraction and the particle shape of its RBCs by using Effective Medium Theory (EMT). Results show that the effect of RBCs concentrations on dielectric and optical properties is minimal while favoring the blood with high RBCs concentration as a better communication medium. Obtained results clearly highlight that the RBCs particle shape has no effect on blood's dielectric and optical properties.

Many risk factors are encountered during the pathogenesis of epilepsy. In this study, the effect of seizure frequency on free radical generation and antioxidants levels in epileptic patients was evaluated. This study was carried out on 15 healthy controls (GI) and 60 epileptic patients treated with mono- or poly-therapy of carbamazepine, valproic acid, or phenytoin. The treated epileptic patients were divided into 2 main groups according to the seizure frequency: controlled seizure patients GII (n = 30) and uncontrolled seizure patients GIII (n = 30). GII included the GIIA subgroup (n = 15) which had been seizure free for more than 12 months and the GIIB subgroup (n = 15) which had been seizure free for a period from 6 to12 months. GIII included GIIIA (n = 15) and GIIIB (n = 15) for patients which had a seizure frequency of less than and more than four times/month, respectively. In comparison to the control group (GI), the levels of nitric oxide (NO) and malondialdehyde/creatinine ratio were significantly increased in GIIB, GIIIA, and GIIIB, while vitamins A and E levels were significantly decreased in GIIIB. Serum NO levels had significant negative correlations with serum vitamin E in the GIIA and GIIB groups, and with vitamin A in the GIIIA and GIIIB groups. However, serum NO had positive correlation with urinary MDA/Cr ratio. The imbalance between free radical generation and antioxidant system in epileptic patients may be a factor in seizure frequency.

Successful management of bladder function mandates a thorough knowledge of the neuroanatomy and physiology of micturition. Accurate urodynamic diagnosis of the exact vesicourethral dysfunction is a key to successful management. The primary concern for the urologist is preservation of renal function, taking into account the social needs of the patient.