King Saud University is a public university located in Riyadh, Saudi Arabia. It was founded in 1957 by King Saud bin Abdul Aziz as Riyadh University, as the first university in the kingdom not dedicated to religious subjects. The university was created to meet the shortage of skilled workers in Saudi Arabia. It was renamed to King Saud University in 1982. The student body of KSU today consists of about 37,874 students of both sexes. Wikipedia.
Morsy M.H.,King Saud University
Renewable and Sustainable Energy Reviews | Year: 2012
Performance of future ignition system for internal combustion engines should be reliable and efficient to enhance and sustain combustion stability, since ignition not only initiates combustion but also influences subsequent combustion. Lean burn systems have been regarded as an advanced combustion approach that could improve thermal efficiency while reducing exhaust gas emissions. However, current engines cannot be operated sufficiently lean due to ignition related problems such as the sluggish flame initiation and propagation along with potential misfiring. A high exhaust gas recirculation engines also has similar potential for emissions improvement, but could also experience similar ignition problems, particularly at idle operation. Similarly, ignition is an important design factor in gas turbine and rocket combustor. Recently, non-conventional ignition techniques such as laser-induced ignition methods have become an attractive field of research in order to replace the conventional spark ignition systems. The fundamentals of conventional laser-induced spark ignition have been previously reviewed. Therefore, the objective of this article is to review progress on the use of such innovative techniques of laser-induced ignition including laser-induced cavity ignition and laser-induced multi-point ignition. In addition, emphasis is given to recent work to explore the feasibility of this interesting technology for practical applications concerning internal combustion engines. © 2012 Elsevier Ltd. All rights reserved.
Syed S.,King Saud University
Hydrometallurgy | Year: 2012
This paper presents an overview of the various methodologies used in the recovery of gold from secondary sources. Gold recovery is interesting due to its vast industrial applications, high market prices and extensively used precious metal, the sanctuary value attributed to gold during international political and economical crises, and the limited resource of this metal may explain the recent increasing gold share value. The state of art in recovery of gold from spent sources by pyrometallurgy; hydrometallurgy; bio-hydrometallurgy techniques is highlighted in this paper. This article also provides an overview of past achievements and present scenario of recovery studies carried out on the use of some promising methods which could serve as an economical means for recovering gold. The present review also highlights the used varieties of leaching, cementing, reducing agents, peeling, coagulants, adsorbents, agglomeration solvents, ion exchange resins and bio-sorbents in real situations and hopes to provide insights into recovery of gold from spent sources. Evaluation of lucrative and environmentally friendly technologies to recover gold from primary and secondary spent sources was made in this study. © 2011 Elsevier B.V. All rights reserved.
Hepbasli A.,King Saud University
Applied Energy | Year: 2011
This study deals with modeling and analyzing the performance of greenhouses from the power plant through the heating system to the greenhouse envelope using exergy analysis method, the so-called low exergy or LowEx approach, which has been and still being successfully used in sustainable buildings design, for the first time to the best of the author's knowledge. For the heating applications, three options are studied with (i) a solar assisted vertical ground-source heat pump greenhouse heating system, (ii) a wood biomass boiler, and (iii) a natural gas boiler, which are driven by renewable and non-renewable energy sources. In this regard, two various greenhouses, the so-called small greenhouse and large greenhouse, considered have heat load rates of 4.15kW and 7.5MW with net floor areas of 11.5m2 and 7.5ha, respectively. The overall exergy efficiency values for Cases 1-3 (solar assisted vertical ground-source heat pump, natural gas boiler and wood biomass boiler) of the small greenhouse system decrease from 3.33% to 0.83%, 11.5% to 2.90% and 3.15% to 0.79% at varying reference state temperatures of 0 to 15°C while those for Cases 1 and 2 (wood biomass and natural gas boilers) of the large greenhouse system decrease from 2.74% to 0.11% and 4.75% to 0.18% at varying reference state temperatures of -10% to 15°C. The energetic renewability ratio values for Cases 1 and 3 of the small greenhouse as well as Case 1 of the large greenhouse are obtained to be 0.28, 0.69 and 0.39, while the corresponding exergetic renewability ratio values are found to be 0.02, 0.64 and 0.29, respectively. © 2011 Elsevier Ltd.
Alzoghaibi M.A.,King Saud University
World Journal of Gastroenterology | Year: 2013
Oxygen free radical and lipid peroxides (oxidative stress) are highly reactive and represent very damaging compounds. Oxidative stress could be a major contributing factor to the tissue injury and fibrosis that characterize Crohn's disease. An imbalance between increased reactive oxygen species levels and decreased antioxidant defenses occurs in Crohn's patients. Decreased blood levels of vitamins C and E and decreased intestinal mucosal levels of CuZn superoxide dismutase, glutathione, vitamin A, C, E, and β-carotene have been reported for Crohn's patients. Increased levels of proinflammatory cytokines, such as interleukin-1 and -8 and tumor necrosis factor, have been detected in inflammatory bowel disease. Oxidative stress significantly increased the production of neutrophils, chemokines, and interleukin-8. These effects were inhibited by antioxidant vitamins and arachidonic acid metabolite inhibitors in human intestinal smooth muscle cells isolated from the bowels of Crohn's disease patients. The main pathological feature of Crohn's disease is an infiltration of polymorphonuclear neutrophils and mononuclear cells into the affected part of the intestine. Activated neutrophils produce noxious substances that cause inflammation and tissue injury. Due to the physiological and biochemical actions of reactive oxygen species and lipid peroxides, many of the clinical and pathophysiological features of Crohn's disease might be explained by an imbalance of increased reactive oxygen species and a net decrease of antioxidant molecules. This review describes the general concepts of free radical, lipid peroxide and antioxidant activities and eventually illustrates their interferences in the development of Crohn's strictures. © 2013 Baishideng. All rights reserved.
Azer S.A.,King Saud University
Academic Medicine | Year: 2015
Purpose To identify and examine the characteristics of the 50 top-cited articles in medical education. Method Two searches were conducted in the Web of Knowledge database in March 2014: a search of medical education journals in the category "Education, Scientific Discipline" (List A) and a keyword search across all journals (List B). Articles identified were reviewed for citation count, country of origin, article type, journal, authors, and publication year. Results Both lists included 56 articles, not 50, because articles with the same absolute number of citations shared the same rank. The majority of List A articles were published in Academic Medicine (34; 60.7%) and Medical Education (16; 28.6%). In List B, 27 articles (48.2%) were published in medical education journals, 19 (33.9%) in general medicine and surgery journals, and 10 (17.9%) in higher education and educational psychology journals. Twenty-six articles were included in both lists, with different rankings. Reviews and articles constituted the majority of articles; there were only 8 research papers in List A and 13 in List B. Articles mainly originated from the United States, Canada, the Netherlands, and the United Kingdom. The majority were published from 1979 to 2007. There was no correlation between year and citation count. Conclusions The finding that over half of List B articles were published in nonmedical education journals is consistent with medical education's integrated nature and subspecialty breadth. Twenty of these articles were among their respective non-medical-education journals' 50 top-cited papers, showing that medical education articles can compete with subject-based articles. Copyright © by the Association of American Medical Colleges. Unauthorized reproduction of this article is prohibited.