University of Bahrain

About: University of Bahrain is a education organization based out in Madīnat ‘Īsá, Bahrain. It is known for research contribution in the topics: Thin film & Doping. The organization has 1650 authors who have published 3405 publications receiving 48162 citations. The organization is also known as: Bahrain University & UoB.

Lifestyle factors associated with overweight and obesity among Saudi adolescents

Abstract: A better understanding of the relationships between obesity and lifestyle factors is necessary for effective prevention and management of obesity in youth. Therefore, the objective of this study was to evaluate the associations between obesity measures and several lifestyle factors, including physical activity, sedentary behaviors and dietary habits among Saudi adolescents aged 14–19 years. This was a school-based cross-sectional study that was conducted in three cities in Saudi Arabia (Al-Khobar, Jeddah and Riyadh). The participants were 2906 secondary school males (1400) and females (1506) aged 14–19 years, who were randomly selected using a multistage stratified cluster sampling technique. Measurements included weight, height, body mass index (BMI), waist circumference, waist/height ratio (WHtR), screen time (television viewing, video games and computer use), physical activity (determined using a validated questionnaire), and dietary habits (intake frequency per week). Logistic regression was used to examine the associations between obesity and lifestyle factors. Compared with non-obese, obese males and females were significantly less active, especially in terms of vigorous activity, had less favorable dietary habits (e.g., lower intake of breakfast, fruits and milk), but had lower intake of sugar-sweetened drinks and sweets/chocolates. Logistic regression analysis showed that overweight/obesity (based on BMI categories) or abdominal obesity (based on WHtR categories) were significantly and inversely associated with vigorous physical activity levels (aOR for high level = 0.69, 95% CI 0.41–0.92 for BMI and 0.63, 95% CI 0.45–0.89 for WHtR) and frequency of breakfast (aOR for < 3 days/week = 1.44; 95% CI 1.20–1.71 for BMI and 1.47; 95% CI 1.22–1.76 for WHtR) and vegetable (aOR for < 3 days/week = 1.29; 95% CI 1.03–1.59 for WHtR) intakes, and consumption of sugar-sweetened beverages (aOR for < 3 days/week = 1.32; 95% CI 1.08–1.62 for BMI and 1.42; 95% CI 1.16–1.75 for WHtR). The present study identified several lifestyle factors associated with obesity that may represent valid targets for the prevention and management of obesity among Saudi adolescents. Primary prevention of obesity by promoting active lifestyles and healthy diets should be a national public health priority.

Optimal Coordination of Directional Overcurrent Relays Using Biogeography-Based Optimization Algorithms

Abstract: Optimal coordination of directional overcurrent relays (DOCRs) is a highly constrained and nonlinear optimization problem. The operating time of each relay depends on two independent variables called plug setting and time multiplier setting. As the network becomes larger and more complex, the number of relays will increase and, thus, finding the optimal solution becomes very hard. In this paper, a new population-based evolutionary algorithm called biogeography-based optimization (BBO) is proposed and the performance of ten types of constraint-handling techniques is evaluated. In addition, a new hybrid BBO with linear programming (BBO-LP) is proposed to enhance the performance of the conventional BBO algorithm. The performance of the proposed BBO-based algorithms is evaluated by using five test systems. The results show the effectiveness and superiority of the proposed algorithms compared with the performance of the other optimization methods presented in the literature.

Cultivation of oyster mushrooms (Pleurotus spp.) on various lignocellulosic wastes

Abstract: Cultivation of speciality mushrooms on lignocellulosic wastes represents one of the most economically and cost-effective organic recycling processes. Three species of Pleurotus, namely P. columbinus, P. sajor-caju and P. ostreatus were experimentally evaluated on untreated organic wastes including chopped office papers, cardboard, sawdust and plant fibres. Production studies were carried out in polyethylene bags of about 1 kg wet weight with 5% spawning rates of substrate fresh weight in a custom-made growth room especially designed for spawn run and cropping. The conversion percentage from dry substrate weight to fresh mushroom weight (biological efficiency) was determined. The highest biological efficiency was noted with P. columbinuson cardboard (134.5%) and paper (100.8%), whereas P. ostreatus produced maximum yield on cardboard (117.5%) followed by paper (112.4%). The overall yield of P. sajor-cajuwas comparatively low (range 47–78.4%). The average number of sporophore flushings ranged between 5 and 6 times. The findings that P. columbinus and P. ostreatus are superior to P. sajor-caju are consistent with previous reports elsewhere. Further evaluation of P. columbinus alone on different bagging systems containing partially pasteurized office papers as a growing substrate revealed that polyethylene bags resulted in 109.4% biological efficiency in contrast to pottery (86%), plastic trays (72%) or polyester net (56%). The above findings reveal an opportunity for commercial implication of oyster mushroom especially P. columbinus for utilization of different feasible and cheap recyclable residues.

Removal of methyl orange dye and Na2SO4 salt from synthetic waste water using reverse osmosis

Abstract: The efficiency of reverse osmosis (RO) membranes used for treatment of colored water effluents can be affected by the presence of both salt and dyes. Concentration polarization of each of the dye and the salt and the possibility of a dynamic membrane formed by the concentrated dye can affect the performance of the RO membrane. The objective of the current work was to study the effect of varying the Na 2 SO 4 salt and methyl orange (MO) dye concentrations on the performance of a spiral wound polyamide membrane. The work also involved the development of a theoretical model based on the solution diffusion (SD) mass transport theory that takes into consideration a pressure dependent dynamic membrane resistance as well as both salt and dye concentration polarizations. Control tests were performed using distilled water, dye/water and salt/water feeds to determine the parameters for the model. The experimental results showed that increasing the dye concentration from 500 to 1000 ppm resulted in a decrease in the salt rejection at all of the operating pressures and for both feed salt concentrations of 5000 and 10,000 ppm. Increasing the salt concentration from 5000 to 10,000 ppm resulted in a slight decrease in the percent dye removal. The model’s results agreed well with these general trends.

The status of renewable energy in the GCC countries

Abstract: Due to the vast growth of development in the infrastructure and investment in energy, the electricity consumption in the GCC countries had increased at a fast rate; 12.4% from 2005 to 2009 (3.15%, annually). This rate is much larger than the world average, which is 2.2% for the same period, or USA (0.5%). In 2005, the average Watt per person in the GCC countries was 1149 which is much higher than the world average (297 W per person) or the European Union (700 W/person) – but less than USA (1460 W/person). The GCC countries need to increase its electrical capacity by 60,000 MW, which represents 80% of the current installed capacity, to meet demand in 2015. This means that there is a need to build 50 more gas fired power generator plant turbine (each rated 1400 MW). The GCC countries have realized that depending on gas will not be the solution due to shortage of resource or environmental impact, particularly the GHG emissions. Therefore, they thought back of using renewable energy resources – after lifting it over in 1990s. They also thought of diversity in electricity production where nuclear energy comes to the picture. The power capacity in GCC countries is at around 75,000 MW, a projected 9.5% growth in annual demand will require more electricity and energy projects; expected to invest USD 200 billion to 250 billion in between 14 and 20 energy projects by 2020. The paper lists the major renewable energy projects (mainly solar and wind) in each of the six GCC countries. The total capacity of these projects exceeds 600 MW. Among these projects is the establishment of the first zero emission house (Green house) in the middle east (7 kW solar, wind and fuel cell) constructed in Bapco residence town (Awali) in Bahrain and therefore, been highlighted more in this paper. Moreover, nearly all GCC countries are planning to construct PV plants with large capacity. Also, several projects in Building Integrated Photovoltaic and Building Integrated Wind Turbines are established in GCC countries. The projects made in the GCC countries allow researchers and investors to size the cost of kWh from thermal, PV and wind energy more precisely. For example, it was found that the cost of kWh from large grid connected solar thermal plant (20 MW) – with cost of USD 72.5 million and energy – is US ¢ 12/kWh (assuming a life time of 40 years and a discount rate of 4%) while, the cost issue of kWh from PV Electricity (in the GCC countries) is ranging from US ¢ 27 (for ground mount) to US ¢ 35 (for roof mount) as it was deduced from two actually installed project PV in UAE – a GCC country member. Meanwhile, the cost of 1 kWh from wind electricity in the GCC countries may be from US ¢10 (large turbine ≈2 MW at 80 m height with good wind speed) to US ¢ 15 (for large turbine ≈2 MW at 80 m height with modest wind speed) while the cost of kWh from grid connected Wind farm plant (20 MW) – with a cost of USD 38.6 million and energy – is US ¢ 6.7/kWh to US ¢ 8.8/kWh, depending on the location of wind farm. This makes it very challengeable for investor, government (Feed-in-Tariff) and citizens because each citizen in GCC countries pays only (US cent 1 for each kWh, for consumption less than 3000 kWh, or even nothing for citizens-like in Qatar).