The University of Bahrain is the largest public university in the Kingdom of Bahrain. In post-nominals it is typically abbreviated as UoB.UoB is primarily, but not exclusively, an undergraduate institution offering postgraduate programs under specific conditions. It is the only national higher education institution in the Kingdom that offers mainly undergraduate B.Sc. degrees and some graduate degrees. Wikipedia.
Haji S.,University of Bahrain
Renewable Energy | Year: 2011
The performance of a fuel cell is characterized by its i-V curve. In this study, the performance of a bench scale fuel cell stack, run on hydrogen/air, is measured experimentally for different air flow rates and temperatures. The experimental data, obtained from the 40-W proton exchange membrane fuel cell (PEMFC), are used in estimating the parameters of a completely analytical model that describes the i-V curve. The analytical model consists of the three fundamental losses experienced by a fuel cell, namely: activation, ohmic, and concentration losses. The current loss is also considered in the model. While the Tafel constants, ohmic resistance, and the concentration loss constant are estimated through regression, the limiting current density and the current loss are obtained through measurements. The effect of temperature on the fuel cell performance, exchange current density, and current loss is also investigated. Both the exchange current density and the current loss are plotted against temperature on an Arrhenius-like plot and the related parameters are estimated. The theoretical equations derived in the literature, which model fuel cell performance, are found to reasonably fit the obtained experimental data. © 2010 Elsevier Ltd.
Dakhel A.A.,University of Bahrain
Thin Solid Films | Year: 2010
Thin films of Fe-doped CdO with 1.3, 2.0, 2.3, 3.0, and 5.7 wt.% were prepared by a vacuum evaporation method on glass and Si wafer substrates. The prepared films were characterised by X-ray fluorescence and diffraction. Results show that doping of CdO with Fe enhances the film's  preferred orientation and causes slight shifts in the (111) Bragg angle towards higher values. The samples were investigated with a UV-VIS-NIR absorption spectroscopy and dc-electrical measurements. It was observed that there is a complicated dependence of bandgap on the Fe wt.% content in the film. In addition, light doping with Fe improves the dc-conduction parameters of CdO, so that with 1.3 wt.% Fe doping, the mobility increases by about 6 times, conductivity by 24 times, and carrier concentration by about 4 times, relative to undoped CdO film. The observations were analysed by using the available models (with a slight modification) for the coexistence of bandgap widening and bandgap narrowing. © 2009 Elsevier B.V. All rights reserved.
Naser H.A.,University of Bahrain
Marine Pollution Bulletin | Year: 2013
The Arabian Gulf is considered among the highest anthropogenically impacted regions in the world. Heavy metals contamination in coastal and marine environments is becoming an increasingly serious threat to both the naturally stressed marine ecosystems and humans that rely on marine resources for food, industry and recreation. Heavy metals are introduced to coastal and marine environments through a variety of sources and activities including sewage and industrial effluents, brine discharges, coastal modifications and oil pollution. The present paper reviews heavy metal contamination in a variety of marine organisms, and sediments, and suggests measures for environmental management of heavy metal pollution in the Arabian Gulf. Most of the reviewed literature confirmed that heavy metal concentrations in marine organisms were generally within allowable concentrations and pose no threat to public health. Likewise, studies suggested that levels of heavy metals in marine sediments are similar or lower compared to other regions. However, localized hotspots of chronic metal pollution in areas influenced by industrial facilities, desalination plants, and oil refineries have been reported. Holistic spatial and temporal monitoring and comprehensive national and regional strategies are critical to combat and manage heavy metal pollution in the Arabian Gulf. © 2013 Elsevier Ltd.
Musaiger A.O.,University of Bahrain
Journal of Obesity | Year: 2011
The objective of this paper was to explore the prevalence of overweight and obesity among various age groups as well as discuss the possible factors that associated with obesity in the Eastern Mediterranean Region (EMR). A systematic review of published papers between 1990 and 2011 was carried out. Obesity reached an alarming level in all age groups of the EMR countries. The prevalence of overweight among preschool children(<5 years) ranged from 1.9% to 21.9%, while the prevalence of overweight and obesity among school children ranged from 7% to 45%. Among adults the prevalence of overweight and obesity ranged from 25% to 81.9%. Possible factors determining obesity in this region include: nutrition transition, inactivity, urbanization, marital status, a shorter duration of breastfeeding, frequent snacking, skipping breakfast, a high intake of sugary beverages, an increase in the incidence of eating outside the home, long periods of time spent viewing television, massive marketing promotion of high fat foods, stunting, perceived body image, cultural elements and food subsidize policy. A national plan of action to overcome obesity is urgently needed to reduce the economic and health burden of obesity in this region. © 2011 Abdulrahman O. Musaiger.
Mattar E.,University of Bahrain
Robotics and Autonomous Systems | Year: 2013
Recently, significant advances have been made in ROBOTICS, ARTIFICIAL INTELLIGENCE and other COGNITIVE related fields, allowing to make much sophisticated biomimetic robotics systems. In addition, enormous number of robots have been designed and assembled, explicitly realize biological oriented behaviors. Towards much skill behaviors and adequate grasping abilities (i.e. ARTICULATION and DEXTEROUS MANIPULATION), a new phase of dexterous hands have been developed recently with biomimetically oriented and bio-inspired functionalities. In this respect, this manuscript brings a detailed survey of biomimetic based dexterous robotics multi-fingered hands. The aim of this survey, is to find out the state of the art on dexterous robotics end-effectors, known in literature as (ROBOTIC HANDS) or (DEXTEROUS MULTI-FINGERED) robot hands. Hence, this review finds such biomimetic approaches using a framework that permits for a common description of biological and technical based hand manipulation behavior. In particular, the manuscript focuses on a number of developments that have been taking place over the past two decades, and some recent developments related to this biomimetic field of research. In conclusions, the study found that, there are rich research efforts in terms of KINEMATICS, DYNAMICS, MODELING and CONTROL methodologies. The survey is also indicating that, the topic of biomimetic inspired robotics systems make significant contributions to robotics hand design, in four main directions for future research. First, they provide a genuine world test of models of biologically inspired hand designs and dexterous manipulation behaviors. Second, they provide novel manipulation articulations and mechanisms available for industrial and domestic uses, most notably in the field of human like hand design and real world applications. Third, this survey has also indicated that, there are quite large number of attempts to acquire biologically inspired hands. These attempts were almost successful, where they exposed more novel ideas for further developments. Such inspirations were directed towards a number of topics related (HAND MECHANICS AND DESIGN), (HAND TACTILE SENSING), (HAND FORCE SENSING), (HAND SOFT ACTUATION) and (HAND CONFIGURATION AND TOPOLOGY). FOURTH, in terms of employing AI related sciences and cognitive thinking, it was also found that, rare and exceptional research attempts were directed towards the employment of biologically inspired thinking, i.e. (AI, BRAIN AND COGNITIVE SCIENCES) for hand upper control and towards much sophisticated dexterous movements. Throughout the study, it has been found there are number of efforts in terms of mechanics and hand designs, tactical sensing, however, for hand soft actuation, it seems this area of research is still far away from having a realistic muscular type fingers and hand movements. © 2013 Elsevier B.V. All rights reserved.
Dakhel A.A.,University of Bahrain
Materials Chemistry and Physics | Year: 2011
Ce-doped CdO thin films with different Cd compositions were prepared on glass and Si wafer substrates by a vacuum evaporation technique. The effects of Ce doping on the structural, electrical, and optical properties of the host CdO films were systematically studied. The X-ray diffraction study shows that some of Ce4+ ions substituted for Cd2+ and the solubility of Ce in CdO is very limited and may be around ∼1.3 at%. The cerium doping influences all optoelectrical properties of CdO. The bandgap of Ce-doped CdO suffers narrowing by about 27% with a small (0.5 at%) doping level. The electrical behaviours show that all the prepared Ce-doped CdO films are degenerate semiconductors. Their dc-conductivity, carrier concentration and mobility increase compare with undoped CdO film. The largest mobility of 66.7 cm2 V-1 s was observed for 3.8% Ce-doped CdO film. From transparent-conducting-oxide point of view, Ce is sufficiently effective for CdO doping. © 2011 Elsevier B.V. All rights reserved.
Naser H.A.,University of Bahrain
Marine Pollution Bulletin | Year: 2011
Coastal reclamation and modifications are extensively carried out in Bahrain, which may physically smother the coastal and subtidal habitats resulting in changes to abundance and distribution of macrobenthic assemblages. A microcosm laboratory experiment using three common macrobenthic invertebrates from a proposed reclaimed coastal area was preformed to examine their responses to mud burial using marine sediment collected from a designated borrow area. Significant difference in numbers of survived organisms between control and experimental treatments with a survival percentage of 41.8% for all of the selected species was observed. The polychaete Perinereis nuntia showed the highest percentage of survival (57.1%) followed by the bivalve Tellina valtonis (42.3%) and the gastropod Cerithidea cingulata (24.0%). Quantifying species responses to sediment burial resulted from dredging and reclamation will aid in predicting the expected ecological impacts associated with coastal developments and subsequently minimizing these impacts and maintaining a sustainable use of coastal and marine ecosystems in the Arabian Gulf. © 2010 Elsevier Ltd.
Al-Laith A.A.A.,University of Bahrain
Journal of Food Composition and Analysis | Year: 2010
Dried desert truffles from Bahraini, Iranian, Moroccan and Saudi origins were examined for their antioxidant and antiradical activities using four analytical methods: ferric reducing ability (FRAP), DPPH, deoxyribose, and nitric oxide (NO). Chemical constituents contributing towards these activities were also investigated. Generally, these truffles possessed varying concentration of antioxidant chemicals averaging 9.6 ± 0.15, 12.0 ± 8.34, 1860 ± 361, 1328 ± 167 and 293 ± 32 mg/100 g dw, for ascorbic, anthocyanins, total esterified phenolics, total free phenolics and total flavonoids, respectively; total carotenoids averaged 681 ± 245 g/100 g dw. Dried truffles also varied with regard to their antioxidant and antiradical activities. The FRAP value averaged 15.41 ± 3.51 mmol/100 g dw. Antiradical activity measured as percent inhibition of DPPH quenching averaged 30.6 ± 12.97% and EC50 of 0.55 ± 0.38 mg. The average EC50 of NO scavenging activity was 159.4 ± 69.3 μg, whereas the average percent inhibition of deoxyribose degradation was 55.9 ± 30.1%. The Iranian truffles yielded the highest in several variables, whereas the Moroccan truffles possessed the lowest values of many variables among the four tested samples. Significant correlation was established between total and free phenolics and FRAP values, and between flavonoids and percent radical inhibition using DPPH, NO and deoxyribose assays. © 2009 Elsevier Inc. All rights reserved.
Janahi E.M.,University of Bahrain
PLoS ONE | Year: 2014
Hepatitis B infection is one of the world's major infectious diseases with about 350 million chronic carriers. Because no data is published on the prevalence and risk factors of this important disease in Bahrain, this article evaluates the available data from 2000 to 2010 to estimate the prevalence of the infection and to evaluate the risk factors. Epidemiologic data on HBV cases were collected from the major hospitals and health centers in Bahrain and statistically analyzed. Over this indicated decade, 877,892 individuals were screened for HBV infection and 5055 positive cases were reported in Bahrain. The prevalence of HBV infection during that period was 0.58%. Although there was no significant difference in the prevalence over the period of 10 years, the actual number of positive cases has almost doubled in the later years especially in 2007 and 2008. The prevalence was significantly higher among males (62.3%; P<0.01). Most cases were associated with non Bahrainis and the prevalence was significantly higher among them (68.3%; P<0.01) than it was among Bahrainis (31.7%). Seventy eight percent (2877/3690) of non Bahraini cases were for citizens of six countries which are highly endemic for HBV, namely India, Pakistan, Bangladesh, Philippines, Indonesia and Ethiopia. Dental procedures and surgical operations were the main risk factors of infection as 37.2% and 35.6% of the patients were probably infected through this route. The prevalence of hepatitis B virus infection in Bahrain indicates that Bahrain had low HBV endemicity for the last 10 years (2000-2010). Our study verifies the significant role played by expatriates/immigrants in the present epidemiology of hepatitis B in Bahrain. Increasing HBV vaccination of high risk groups, active educational and media campaign, screening HBV infection during pregnancy, and surveillance of hepatitis B infected individuals will further decrease the prevalence of the disease in Bahrain. © 2014 Essam M. Janahi.
Talaq J.,University of Bahrain
International Journal of Electrical Power and Energy Systems | Year: 2012
Excitation supplementary control is used in power systems to enhance the damping of low frequency oscillations due to the mechanical modes of the generators. Traditionally, frequency deviation is fed back to the exciter through phase lag-lead compensators to form the supplementary control. This supplementary control is known as power system stabilizer (PSS). An optimal power system stabilizer (OPSS) based on linear quadratic regulator design and utilizing the conventional phase lag-lead structure of PSS is presented in this paper. Furthermore, a suboptimal power system stabilizer (SOPSS) is proposed by neglecting the coupling gains between machines and feeding back only the speed deviation and the PSS states. The OPSS and SOPSS are compared with the conventional phase lag-lead power system stabilizer and simulation results of several power system examples are presented. © 2012 Elsevier Ltd. All rights reserved.