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Search Results: 1 - 10 of 467691 matches for " Taher A. Ba-Omar "
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Technology Acceptance: Course and Teaching Surveys Case Study at Sultan Qaboos University
Ali H. Al-Badi,Abdullah S. Al-Rashdi,Taher A. Ba-Omar
IBIMA Business Review , 2011,
Abstract: Course and teaching surveys (CTS) are an integral part of academic life in institutions of higher education. CTS are conducted with the aim of informing the University's commitment to continuous improvement in the delivery of high quality learning experiences for students. They are used also to gauge the students’ satisfaction with the course materials and the instructor(s) and to provide feedback to the instructor(s). Paper based surveys, for historical reasons, are frequently used for this task. With the rolling out of low cost and accessible web based systems, it is now possible to deploy computer-based instead of paper-based surveys. Paper based surveys present a problem due to the extensive amount of paper handling required, and offer greater potential for abuse by certain individuals. Electronic surveys facilitate more efficient development, distribution and reporting processes, but have some issues with motivating student responses. The objective of this research is of two folds; first, to explore the usefulness and effectiveness of using the web-based surveys in contrast to the paper-based ones by obtaining the opinions of the stakeholders (students, faculty members and staff); and secondly to investigate the causes behind the low number of students attempting the web-based surveys in comparison to the paper-based.Interviews with stakeholders) give different perspectives on this matter. Experience with a paper based survey, and the implementation of an electronic replacement at Sultan Qaboos University (SQU), allows the two approaches to be compared. The paper also investigates the acceptability and willingness of the students to use the newly created web-based survey. Many researchers have written about the Technology Acceptance Model (TAM), and some have provided extensions to the initially proposed model. In this paper we present a case study confirming the Perceived Usefulness of Technology (PUT) component of TAM, and how this factor influences a customer’s willingness to use a technology. The study showed clearly that the web-based CTS have much more advantages over the paper-based ones. Furthermore, if a user does not believe a technology is useful he/she will not use it. Many students claimed that they believe that the CTS have no benefits if there are not actions to be taken by the administration. The paper concludes by providing some recommendations to encourage people to use the technology under discussion, an on-line survey service.
Model Associated with the Study of the Degradation Based on the Accelerated Test: A Literature Review  [PDF]
Fatou Dia, Nacire Mbengue, Omar Ngalla Sarr, Moulaye Diagne, Omar A. Niasse, Awa Dieye, Mor Niang, Bassirou Ba, Cheikh Sene
Open Journal of Applied Sciences (OJAppS) , 2016, DOI: 10.4236/ojapps.2016.61006
Abstract: Most manufacturers of solar modules guarantee the minimum performance of their modules for 20 to 25 years, and 30-year warranties have been introduced. The warranty typically guarantees that the modules will perform to at least 90% capacity in the first 10 years and to at least 80% in the following 10 - 15 years. Early degradation resulting from design flaws, materials or processing issues is often apparent from startup to the first few years in service. Importantly, many module failures and performance losses are the result of gradual accumulated damage resulting from long-term outdoor exposure in harsh environments, referred. Many of these processes occur on relatively long time scales and the various degradation processes may be chemical, electrical, thermal or mechanical in nature. These are either initiated or accelerated by the combined stresses of the service environment, in particular solar radiation, temperature and moisture, and other stresses such as salt air, wind and snow. Accelerated Life Testing (ALT) test methodology is normally predicated on first being able to reproduce a specific degradation or failure mode without altering it (correlation); and, second, to produce that result in less than real-time acceleration. Degradation and failure may result when an applied stress exceeds material or product strength. This may be a one-time catastrophic event, the result of cyclic fatigue, or a gradual decline in requisite properties due to ageing mechanisms. Engineers in the manufacturing industries have used accelerated test (AT) experiments for many decades. The purpose of AT experiments is to acquire reliability information quickly. Test units of a material, component, subsystem or entire systems are subjected to higher-than-usual levels of one or more accelerating variables such as temperature or stress. Then the AT results are used to predict life of the units at use conditions. The extrapolation is typically justified (correctly or incorrectly) on the basis of physically motivated models or a combination of empirical model fitting with a sufficient amount of previous experience in testing similar units. The need to extrapolate in both time and the accelerating variables generally necessitates the use of fully parametric models. Statisticians have made important contributions in the development of appropriate stochastic models for AT data [typically a distribution for the response and regression relationships between the parameters of this distribution and the accelerating variable(s)], statistical methods for AT planning (choice of
Synthesis of novel 3,4-dihydroquinoxalin-2(1H)-one derivatives
Mohammed Shabaan,Azza Taher Taher,Eman Omar Osman
European Journal of Chemistry , 2011, DOI: 10.5155/eurjchem.2.3.365-371.289
Abstract: New derivatives of 3,4-dihydroquinoxaline-2(1H)-one were synthesized and characterized. Representative examples were evaluated for their antimicrobial and antifungal activities using Tetracycline and Nystatin as reference compound. One of the tested compounds 10a was found to exhibit slight activity against Staphylococcus aureus. Compounds 10b, 11b and 14b showed slight activity against Escherichia coli. Moreover, nineteen compounds were screened for their inhibition effect on CDK5, CK1, and GSK-3β. None of the tested compounds showed an inhibition activity below 10 μM concentration.
Approximate Solutions for Nonlinear Initial Value Problems Using the Modified Variational Iteration Method
Taher A. Nofal
Journal of Applied Mathematics , 2012, DOI: 10.1155/2012/370843
Abstract: We have used the modified variational iteration method (MVIM) to find the approximate solutions for some nonlinear initial value problems in the mathematical physics, via the Burgers-Fisher equation, the Kuramoto-Sivashinsky equation, the coupled Schrodinger-KdV equations, and the long-short wave resonance equations together with initial conditions. The results of these problems reveal that the modified variational iteration method is very powerful, effective, convenient, and quite accurate to systems of nonlinear equations. It is predicted that this method can be found widely applicable in engineering and physics.
Measurement of Radon Concentrations and Their Annual Effective Dose Exposure in Groundwater from Qassim Area, Saudi Arabia
A. El-Taher
Journal of Environmental Science and Technology , 2012,
Abstract: Radon is a radioactive noble gas of a natural origin that may be found anywhere in soil, air and in different types of water. It is worthy to carry out the distribution of radon (222Rn) activity concentration and their annual effective dose exposure in groundwater samples from Qassim area, Saudi Arabia. Radon concentrations were measured by using RAD7 an electronic radon detector connected to a RAD-H2O accessory (Durridge Co., USA). The measured radon concentration ranges from 0.76 to 4.69 Bq L-1 with an average value of 2.8 Bq L-1. The measured values of radon concentration are well in the range within the EPA’s Maximum Contaminant Level (MCL) of 11.1 Bq L-1. The total annual effective dose resulting from radon in groundwater of Qassim area were significantly lower than the (United Nations Scientific Committee on the Effects of Atomic Radiation UNSCEAR and World Health Organization WHO) recommended limit for members of the public of 1 mSv year-1. The measured values for underground water from the study area suggest that the area is safe for farmers and there is no significant threat to the population as per as radon concentration is concerned.
Application of Homotopy Perturbation Method and Parameter Expanding Method to Fractional Van der Pol Damped Nonlinear Oscillator  [PDF]
Taher A. Nofal, Gamal M. Ismail, Sayed Abdel-Khalek
Journal of Modern Physics (JMP) , 2013, DOI: 10.4236/jmp.2013.411179

In this study, homotopy perturbation method and parameter expanding method are applied to the motion equations of two nonlinear oscillators. Our results show that both the (HPM) and (PEM) yield the same results for the nonlinear problems. In comparison with the exact solution, the results show that these methods are very convenient for solving nonlinear equations and also can be used for strong nonlinear oscillators.

Omission of the Bladder Flap Suggests Short Term and Long Term Benefits  [PDF]
Mona Omar, Manal A. Farahat
Open Journal of Obstetrics and Gynecology (OJOG) , 2019, DOI: 10.4236/ojog.2019.95055
Abstract: Background: Cesarean section is now the most common major surgical procedure performed on women worldwide. With the increasing numbers of cesarean sections, there is the need to utilize evidence based techniques to optimize outcomes and minimize complications. We hypothesize that omission of the bladder flap in both primary and repeat cesarean sections will be associated with shorter operating time without a significant increase in intraoperative and postoperative complications. Methods: 550 patients were enrolled in the study. They were randomly allocated in the 2 groups to evaluate the effects of cancelling the bladder dissection. Results: Significant reduction of the total operating time (p = 0.01), skin to delivery time (p = 0.02) and micro-hematuria (p = 0.01) in group with bladder omission. Long term result: Including more bladder adhesion and fibrosis in the cases with bladder dissection. Conclusions: Omission of the bladder dissection achieved short-term advantages as regards reduction of operating time, incision-delivery duration and decreased blood loss as well as long-term effects include different in the bladder adhesion.
Thin Film Characterization Using Rotating Polarizer Analyzer Ellipsometer with a Speed Ratio 1:3  [PDF]
Sofyan A. Taya, Taher M. El-Agez, Anas A. Alkanoo
Journal of Electromagnetic Analysis and Applications (JEMAA) , 2011, DOI: 10.4236/jemaa.2011.39056
Abstract: In a recent previous work, we proposed a rotating polarizer-analyzer ellipsometer (RPAE) in which the two elements are rotating synchronously in the same direction with a speed ratio 1:3. We applied this technique to bulk samples. In this work, we present theoretically the characterization of 100 nm SiO2 thin film using this spectroscopic RPAE. We assume a structure consisting of air (ambient)/SiO2 (thin film)/c-Si (substrate). The ellipsometric parameters ψ and Δ are calculated when a clean signal is received by the detector and when a hypothetical noise is imposed on this signal. The film thickness and the optical constants of the film are calculated for the noisy signal in the spectrum range 200 - 800 nm. The results are compared with the proposed thickness and with the accepted values for SiO2 optical constants.
Analysis and Design of a New Method for Reduction of Touch and Step Voltages for Earthing Systems Using FEM Approach
S.A. Taher,A. Shemshadi
International Journal of Electrical and Power Engineering , 2012,
Abstract: A new design method for earthing system electrode arrangement and analyzing process using finite element method (FEM) to estimate the solution of the second order laplace type differential equation forced on the proposed system is explained. The surge or earth unbalance current flow in electric power system leads to increased touch and step voltages. Insulating the upper part of earthing system electrodes, proposed in this paper as a new method, causes reduction of touch and step voltages when current flows through the earth as a result of unbalance/surge currents. This is an important safety factor which must be considered for those who work on such electrical sites. Because of independence of the unbalance earth current from the total earth resistance, in high values of it will result in increased touch and step voltages to dangerous values. This research specially refers to the power plants and high voltage substations which have been installed in high resistance soil like rocky earth sites.
Novel Method for Determining the Maximally Productive Units using DEA
A.H. Taher,A. Malek
Journal of Applied Sciences , 2009,
Abstract: In this study, we propose a new method for determine maximally productive units based on input-output orientation data envelopment analysis. In this method, we find that reduce inputs and improve outputs units without regard to any factor weights is possible. The new method is a linear mathematical programming technique that determines the intensities of units. No assumptions are required on the internal transformation processes of the units. Decision making depends critically on the way excellent units are frequently described. Present findings have implications for the monitoring and financing of units. Some units with the maximal productivity should be considered as a guide for the other units to reduce inputs and improve outputs units. Numerical illustrations are provided for 15 hospitals dataset of Sherman and 12 hospitals in Tehran, Iran.
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