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Search Results: 1 - 10 of 149992 matches for " Ihab H. Farag "
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Nkongolo Mulumba,Ihab H. Farag
International Journal of Engineering Science and Technology , 2012,
Abstract: Biodiesel production from algae is a promising technique. Microalgae have the potential to produce 5,000-15,000 gallons of biodiesel/(acre-year). However, there are challenges; these include high yieldof algae biomass with high lipid content and the effective technique to harvest the grown algae, extract the algal oil and transesterify the oil to biodiesel. In this project Tubular PhotoBioReactor (TPBR) was designed and achieved a ten times increase in algae concentration. It produced 1g of dry algal biomass per liter of medium within 12 days, with a lipid content of 12% approximately. Healthy algal culture grew well in the TPBR reaching 56x106 cells/mL of culture medium. The 10 fold increase is higher than those reported for open ponds and helical photobioreactor.
Gina Chaput,Kyle Charmanski,Ihab H. Farag
International Journal of Engineering Science and Technology , 2012,
Abstract: The increasing scarcity of fossil fuels has forced industry to look for new cost effective, clean,and sustainable sources of energy. With recent advances in technology, biofuels have become a more viableoption. Microalgae are cost effective and efficient feedstock for the production of biodiesel. One of the algae advantages is the ability to grow it in a wastewater media. This provides essential nutrients without the addition of chemicals. When grown in a photobioreactor, the algae can be cultivated on non-arable land, preventing competition with food supply unlike other leading biodiesel feedstocks such as canola and soybean crop. The strain of algae used in this study was Chlorella sp. The primary goals of this project were to determine the viability of algae growth in a wastewater medium, test the effectiveness of an alternate nitrogen source, andexamine the effects of CO2 fertilization on algae growth and lipid content. Sodium bicarbonate was used to simulate CO2 fertilization. Results showed that: the use of a 50/50 wastewater/reverse osmosis (RO) medium yielded 83% of the lipid productivity of a 100% RO medium while the 100% wastewater medium yielded 35% of the lipid productivity; urea as a substitute for KNO3 in 100% RO, 50/50, and 100% Wastewater medium increased lipid productivity by 1.4%, 52.3%, and 88.3%, respectively. The lipid productivity of urea 100% wastewater medium was increased by 68.9% when fertilized with sodium bicarbonate. The optimum trial, a urea 100% wastewater medium with daily additions of sodium bicarbonate, had a lipid productivity of 0.062 grams/liter of growth medium and a volumetric biomass yield of 0.15 grams per liter-day.
Computing optimal control with a quasilinear parabolic partial differential equation
M. H. Farag
Surveys in Mathematics and its Applications , 2009,
Abstract: This paper presents the numerical solution of a constrained optimal control problem (COCP) for quasilinear parabolic equations. The COCP is converted to unconstrained optimization problem (UOCP) by applying the exterior penalty function method. Necessary optimality conditions for the considered problem are established. The computing optimal controls are helped to identify the unknown coefficients of the quasilinear parabolic equation. Numerical results are reported.
Phosphate Solubilization by Bacillus subtilis and Serratia marcescens Isolated from Tomato Plant Rhizosphere  [PDF]
Eman A. H. Mohamed, Azza G. Farag, Sahar A. Youssef
Journal of Environmental Protection (JEP) , 2018, DOI: 10.4236/jep.2018.93018
Abstract: Plants need phosphorus for many physiological activities in a form of phosphate anions. Three different bacterial strains (Bacillus subtilis PH, Serratia marcescens PH1, and Serratia marcescens PH2), recently isolated from tomato plant rhizosphere, have high phosphate solubilization index (SI from 2.8 to 3.2) on Pikovskaya agar medium (which contains calcium phosphate). Moreover, phosphate release from calcium in Pikovskaya broth over 5 days is increasing with cell growth for the different isolates. The most efficient phosphate solubilization case is the mixed culture of the 3 strains (OD475 is almost 1). On the other hand, pH values decreased dramatically with time due to organic acids secretion and the maximum acidification level is recoded for Serratia marcescens PH2 (pH = 1.94). Interestingly, the isolates are resistance to important pesticides (oxamyl, thiophanate methyl, and captan) that are commonly used in the sampling area. This resistance is very favorable and increases the persistence of the phosphate solubilizing bacteria in contaminated soils. The isolates are therefore plant symbionts and growth promoting agents.
Uncertainty Estimation due to Geometrical Imperfection and Wringing in Calibration of End Standards
Salah H. R. Ali,Ihab H. Naeim
ISRN Optics , 2013, DOI: 10.1155/2013/697176
Abstract: Uncertainty in gauge block measurement depends on three major areas, thermal effects, dimension metrology system that includes measurement strategy, and end standard surface perfection grades. In this paper, we focus precisely on estimating the uncertainty due to the geometrical imperfection of measuring surfaces and wringing gab in calibration of end standards grade 0. Optomechanical system equipped with Zygo measurement interferometer (ZMI-1000A) and AFM technique have been employed. A novel protocol of measurement covering the geometric form of end standard surfaces and wrung base platen was experimentally applied. Surface imperfection characteristics of commonly used 6.5?mm GB have been achieved by AFM in 2D and 3D to be applied in three sets of experiments. The results show that there are obvious mapping relations between the geometrical imperfection and wringing thickness of the end standards calibration. Moreover, the predicted uncertainties are clearly estimated within an acceptable range from 0.132?μm, 0.164?μm and 0.202?μm, respectively. Experimental and analytical results are also presented. 1. Introduction In nonmetrology, estimation of uncertainty in dimension measurements is a vital part in calibration processes. The uncertainty estimation is always influenced by the procedures and the conditions of length measurement. End-to-end effects in calibration of end standards are constantly a necessary part in length metrology. From the calibration of primary length standards (a stabilized laser wavelength) to the calibration of secondary end standards (gauge blocks, GBs), it was important to accurately identify the major impacts on the uncertainty estimation. There are many grades of gauge blocks (00, , 0, and industrial grade) that are commonly working as end standards in different accurate industrial applications, especially in automotive and airspace industries. One must know the requirements of gauge blocks: the surfaces must have a smooth finish, the surfaces must be flat, the double faces must be parallel, and the actual size must be known as a natural expression of the nominal size [1, 2]. Materials of GBs are made including specific conditions such as hardness, temperature stability, corrosion resistance, and high-quality finish. Figure 1 emphasizes the truth of the metrologists saying “No surface is perfectly smooth.” The surface of GB is rarely so flat or smooth, but most commonly it is a combination between the tolerances limits and due to the surface finish quality. In dimensional metrology, such calibration should be performed to
Idiopathic Low-Flow Priapism in Prepuberty: A Case Report and a Review of Literature
Ihab A. Hekal,Eric J. H. Meuleman
Advances in Urology , 2008, DOI: 10.1155/2008/549861
Abstract: Introduction. The incidence of priapism in adults is higher than in children. Although approximately 50% of all episodes of priapism are thought to be idiopathic, there are a number of known specific causes of this disorder. In adults intracavernous therapy with papaverine, phentolamine, alprostadil or combinations of these agents is the most common cause of ischemic priapism. In children the most common etiology is sickle cell anemia for low-flow priapism or post-traumatic high-flow priapism. We present a 13-year-old boy, not sexually active presented to our outpatient clinic suffering from long standing (3.5 hours) sustained painful erection. To the best of our knowledge the idiopathic low-flow priapism in pre-pubertal boy was not reported before in literature. Our case is the first case to be reported in pre-pubertal age. Conclusion. In pre-pubertal boys idiopathic recurrent priapism is a rare condition. In the literature, several empirical therapies are described. Recently, it is postulated that a low dose of a PDE5 inhibitor. The early conservative management is the best treatment option to safe the corporeal smooth muscles from irreversible damage.
The Effect of Atorvastatin on Liver Function among Patients with Coronary Heart Disease in Gaza Strip  [PDF]
Mahmmoud H. Taleb, Ihab M. Almasri, Naima I. Siam, Ahmed A. Najim, Adham I. Ahmed
Pharmacology & Pharmacy (PP) , 2014, DOI: 10.4236/pp.2014.58088

Statins, which are inhibitors of 3-hydroxy-3-methylglutaryl-CoA (HMG-CoA) reductase, are considered as one of the most important drugs and the drug of choice for reducing an abnormal cholesterol level. Statins are normally used to decrease the risk of coronary heart disease (CHD), but they tend to be associated with liver adverse effects. The objective of this prospective study was to investigate the effect of atorvastatin therapy on the liver function in patients with CHD. Study comprised of 66 newly diagnosed CHD patients who were selected from UNRWA clinics in the Gaza Strip. The patients were clinically examined and treated with atorvastatin (10 - 40 mg/day). A questionnaire was used to collect the data concerning patient’s characteristics. Total cholesterol (TC), triglycerides (TG), high density lipoprotein cholesterol (HDL-C), low-density lipoprotein cholesterol (LDL-C), liver enzymes tests such as alanine aminotransferase (ALT) and aspartate aminotransferase (AST) and total and direct blood bilirubin were measured before starting treatment and after 3 and 6 months of treatment. The results showed a significant increase in the mean values of ALT, AST, total bilirubin and direct bilirubin levels after 3 months then decreased after the next 3 months, but they were higher than the baseline with insignificant association.

Influence of microwave heating on the stability of processed samn
Farag, Radwan S.,Taha, Soad H.
Grasas y Aceites , 1991,
Abstract: Butter was converted to samn by microwave and conventional heating. The quality of the processed samn by the two methods was followed by determining the acid, peroxide and TBA values over a period of six weeks at 60°C. The fatty acid composition of samn samples was determined by gas-liquid chromatographic technique. The data show that butter conversion to samn by microwave heating was accomplished in about one half of the time that conventional heating requires. Microwave heating obviously increased the development of samn rancidity compared with the conventional heating. The parameters used for measuring lipid rancidity indicated that the main cause of samn rancidity under the present conditions is an oxidation mechanism. Mantequilla fue transformada en samn por calentamiento en microonda y convencional. La calidad del elaborado de samn por los dos métodos fue seguida mediante determinación de los índices de acidez, peróxido y TBA durante un período de seis semanas a 60°C. La composición en ácidos grasos de muestras de samn fue determinada por técnica cromatográfica gas-líquido. Los datos mostraron que la conversión de mantequilla a samn por calentamiento en microonda fue realizada en aproximadamente una vez y media el tiempo que exige el calentamiento convencional. El calentamiento en microonda, evidentemente, aumentó el desarrollo de la rancidez del samn comparado con el calentamiento convencional. Los parámetros usados para la medida de la rancidez lipídica indicaron que la causa principal de la rancidez del samn bajo las condiciones presentes es un mecanismo de oxidación.
Lorentz Invariance Violation and Generalized Uncertainty Principle
A. Tawfik,H. Magdy,A. Farag Ali
Physics , 2012,
Abstract: Recent approaches for quantum gravity are conjectured to give predictions for a minimum measurable length, a maximum observable momentum and an essential generalization for the Heisenberg uncertainty principle (GUP). The latter is based on a momentum-dependent modification in the standard dispersion relation and leads to Lorentz invariance violation (LIV). The main features of the controversial OPERA measurements on the faster-than-light muon neutrino anomaly are used to calculate the time of flight delays $\Delta t$ and the relative change $\Delta v$ in the speed of neutrino in dependence on the redshift $z$. The results are compared with the OPERA measurements. We find that the measurements are too large to be interpreted as LIV. Depending on the rest mass, the propagation of high-energy muon neutrino can be superluminal. The comparison with the ultra high energy cosmic rays seems to reveals an essential ingredient of the approach combining string theory, loop quantum gravity, black hole physics and doubly spacial relativity and the one assuming a pertubative departure from exact Lorentz invariance.
Effects of quantum gravity on the inflationary parameters and thermodynamics of the early universe
A. Tawfik,H. Magdy,A. Farag Ali
Physics , 2012, DOI: 10.1007/s10714-013-1522-0
Abstract: The effects of generalized uncertainty principle (GUP) on the inflationary dynamics and the thermodynamics of the early universe are studied. Using the GUP approach, the tensorial and scalar density fluctuations in the inflation era are evaluated and compared with the standard case. We find a good agreement with the Wilkinson Microwave Anisotropy Probe data. Assuming that a quantum gas of scalar particles is confined within a thin layer near the apparent horizon of the Friedmann-Lemaitre-Robertson-Walker universe which satisfies the boundary condition, the number and entropy densities and the free energy arising form the quantum states are calculated using the GUP approach. A qualitative estimation for effects of the quantum gravity on all these thermodynamic quantities is introduced.
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