OALib Journal期刊

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匹配条件: “ Ahmad Ahmad” ,找到相关结果约7861条。
Efficiency and Duality in Nondifferentiable Multiobjective Programming Involving Directional Derivative  [PDF]
Izhar Ahmad
Applied Mathematics (AM) , 2011, DOI: 10.4236/am.2011.24057
Abstract: In this paper, we introduce a new class of generalized dI-univexity in which each component of the objective and constraint functions is directionally differentiable in its own direction di for a nondifferentiable multiobjective programming problem. Based upon these generalized functions, sufficient optimality conditions are established for a feasible point to be efficient and properly efficient under the generalised dI-univexity requirements. Moreover, weak, strong and strict converse duality theorems are also derived for Mond-Weir type dual programs.
Visco-Elastic Boundary Layer Flow past a Stretching Plate and Heat Transfer with Variable Thermal Conductivity  [PDF]
Naseem Ahmad
World Journal of Mechanics (WJM) , 2011, DOI: 10.4236/wjm.2011.12003
Abstract: In the present paper, the boundary layer flow of Walters Liquid B Model over a stretching plate has been considered to solve heat flow problem with variable conductivity. First, using similarity transformation, the velocity components of velocity have been obtained. Then, the heat flow problem has been considered in two ways: 1) prescribed surface temperature (PST), and 2) prescribed stretching plate heat flux (PHF) in case of variable conductivity. Due to variable conductivity, temperature profile has its two part- one mean tempera-ture and other temperature profile induced due to variable conductivity. The related results have been dis-cussed with the help of graphs.
Intelligent MSW Biocell Approach for Efficient Methane Production  [PDF]
Ahmad Qasaimeh
Computational Water, Energy, and Environmental Engineering (CWEEE) , 2012, DOI: 10.4236/cweee.2012.12003
Abstract: The aim of this research is to provide approach to enhance methane production and to convert CO2 released into methane via anaerobic degradation. Despite CH4 has more global warming potential than CO2 but it is less available in the environment and it has fuel value. This research suggests approach that methane is being stimulated and carbon dioxide is being converted to methane. The methane enhancement herein is achieved via technical and intelligent processes. The technical processes entail leachate and carbon dioxide recirculation. The recirculated leachate is controlled via fuzzy intelligent system that acquires values of abiotic factors such as C:N:P, pH, temperature, and moisture content, and then these values are introduced to trained fuzzy system to decide the value of methane production quality. The fuzzy logic proceeds in systematic sequence as input, inference through rules, and output. If the fuzzy logic output decision indicates bad production, then the value of aboitic factors are dynamically altered with optimized combination of values. Carbon dioxide is being re-circulated in order to convert it biologically to methane by hydrogenotrophic methanogens. The hydrophobic permeable membranes are used as planes through the solid waste. These selective membranes are used to separate biogas and to have smooth and fast transfer of biogas from waste to the storage. The approach of this research is believed to be as a new generation of sustainable green bio-fuel biocells.
Root Analogous Solid Waste Management System (RA-MSW for Biocells)  [PDF]
Ahmad Qasaimeh
Journal of Environmental Protection (JEP) , 2012, DOI: 10.4236/jep.2012.38090
Abstract: Root Analogous Municipal Solid Waste System “RA-MSW” is a novel management system that manages waste, biogas, and leachate in bioreactor landfill. Different than conventional disposal at landfills, waste is penetrated by synthetic roots that serve dual mission for biogas collection and leachate recirculation. RA-MSW roots are permeable hydropho- bic polymer material that are formed on-place or prefabricated at factory from recyclable material available on the dumping area. Since the material is hydrophobic, it does not contain water in the voids providing more space for gas transport and collection. The roots are also interchangeably used for leachate recirculation where the parameters of wa- ter content, nutrients, pH, and temperature are optimized to enhance biogas production simultaneously with leachate treatment. RA-MSW provides new approach of waste management and control; it has new virtues of landfill operation; new material medium for biogas collection; new biocell design configuration; new manipulation for leachate and biogas. The approach adds new merits for solid waste management, bio-energy utilization, and the concept of 5 R’s cycle for MSW management.
Solar Energy Optimization through Seasons: Case Study in Jordan  [PDF]
Ahmad Qasaimeh
Smart Grid and Renewable Energy (SGRE) , 2012, DOI: 10.4236/sgre.2012.34038
Abstract: Solar energy in Jordan is recognized high amongst in the world. The solar energy cultivation needs to be magnified by optimizing the angle of inclination of solar cells. The angle of inclination in this work is not fixed but variable throughout the year, and consequently the angle is optimized for seasons. In this research, the optimized angles for seasons in Jordan are obtained as: 60? for Winter (November to February), 30? for Spring (March and April), 10? for Summer (May to August), and 30? for Fall (September and October). The optimized cultivated energy throughout all seasons in the year equals about 2490 kWh/m2. The residential customer consumption of electricity is 2475 kWh/customer per year. Therefore, according to Jordan, if the sun energy is converted efficiently to electricity, it will be worthy to apply for residential building for which each customer should have some area of solar cells to overcome the needs of energy. In addition, with some wise management of electricity in the daylight period, fossil fuel consumption will be minimized. Hence, combining solar energy concept in the design of building is an important step in sustainable development of green energy.
Time-seismicity evolution and seismic risk assessment of the Arabian plate  [PDF]
Ahmad Bilal
Natural Science (NS) , 2013, DOI: 10.4236/ns.2013.59126

The seismicity of the Arabian plate, which is the aim of this paper, is controlled by the ZagrosTaurus collision zone in the North, the Indian expansion zone and the Arab golf in the South and the East, the Dead Sea Fault, the North continuity of the Red Sea, and the Syrian rift, which links the rigid Arabian plate to the mobile ophiolite belt of Cyprus-Southern Turkey in the West. These major elements with their related fracture system, make the Arabian plate an important seismic centre. To attain our purpose, a variable methodology is used in: measurements of movement rate-displacement in the field, the analysis of historical and recent seismic data, and physical effects on the structures. The movement rate-displacement, calculated in the field by different specialists, varies from 2 to 6 mm/year. This rate increases from 2 - 3 mm/year in the North, to 6 mm in the South. These estimations are confirmed by historical seismic data, the recent seismic recorded by the Arab seismic centers, and physical effects on the building structures in the region. The analysis of historical and recent seismic data recorded in the seismic centre show that the seismicity in this plate, tend to fade out with time. This result is in agreement with recent estimations on the movement rate, and in line with the decrease of major seismic intensity, which has occurred during the last millennium. A conclusion of time-evolution seismicity is traced, and a seismic zoning map, for the Arabian plate, using movement rate, seismic data, and tectono-geodynamic analysis, is proposed.

Arab metallurgy owes much to meteorites iron—A special regard to Damask saber  [PDF]
Ahmad Bilal
Natural Science (NS) , 2014, DOI: 10.4236/ns.2014.62012

Ancient Arabs have recognized metallic and mineral ores, including their fluid inclusions which were still considered as a new scientific fields in the 70’s last century. They discovered metallic ores (gold, silver, copper), in inhabited areas and in delta and river crosses, using different techniques for exploration and exploitation. Metallic industry flourished during the Islamic period, silver and gold were used as currency for commercial exchanges. Meteorites were also recognized by Ancient Arabs. They collected them in the deserted areas, and used them for arms manufacturing, as sabers and daggers. The more famous of these arms is the Damask saber steel, known reputedly Jaohar. It has an extraordinary mechanical properties, and exceptional sharp cutting edge. The Jaohar blades were forged directly from fall meteorites, at temperature of 80℃, using a sophistical thermomechanical of forging, annealing to refine the steel, and giving it this exceptional quality and superelastic behavior. Meteorites using by Ancient Arabs come back to 400 years ago, as confirmed by a recent research on two meteorites samples, presented in Aleppo museum, found in Ras Shamra, and Umm El Maraa, in Syria.

Globalization of Science and Technology through Research and Development  [PDF]
Aqueil Ahmad
Open Journal of Social Sciences (JSS) , 2014, DOI: 10.4236/jss.2014.24031
Abstract: Globalization of science and technology is an integral aspect of globalization per se. The main engine of globalization is assumed to be the global economy propelled by global trade and technology transfers, the latter as aspects of globalization of science and technology. International trade and technology transfers are the engines that drive global economy. Much has been written on these drivers but relatively little on what drives globalization of science and technology which constitutes the backbone of international technology transfers. I attempt to fill this knowledge gap by suggesting that the drivers behind globalization of science and technology are the emerging global centers of collaborative research and development (R&D) as constituents of the global invisible college(s). “Science” throughout this article means both science and technology as the two closely related aspects of the same knowledge system.
Low-Noise Front-End Receiver Dedicated to Biomedical Devices: NIRS Acquisition System  [PDF]
Ahmad Chaddad
Circuits and Systems (CS) , 2014, DOI: 10.4236/cs.2014.58021
Abstract: This paper concerns the design and the implementation of a fully integrated front-end intended to Near-Infrared Spectroscopy System (NIRS) acquisition system. A low-noise transimpedance amplification (TIA) circuit followed by adjustable cut-off frequency and a low-pass filter (LPF) was implemented in order to decrease noise circuit of NIRS detectors. For TIA, a single ended common source, common gate input stage based on a cascode structure is used to get a higher gain-bandwidth closed-loop transimpedance amplifier. To enhance the circuit noise performance, a single feedback transistor technique is used, compared to passive feedback, to achieved high quality data from NIRS acquisition channel. The proposed LPF combines two control methods to adjust the low cut-off frequency. Simulation results show a TIA gain of 104.2 dBΩ, ?3dB bandwidth of 19 MHz and an equivalent input noise current spectral density of 446 fA/√Hz. LPF filter exhibits a relatively constant noise 201nV/√HzQUOTE√Hz from 0 Hz to 700 KHz and linearity performance over its entire tuning range. The proposed front-end of NIRS preamplifier is implemented using 0.18 μm CMOS technology.
Brain Function Diagnosis Enhanced Using Denoised fNIRS Raw Signals  [PDF]
Ahmad Chaddad
Journal of Biomedical Science and Engineering (JBiSE) , 2014, DOI: 10.4236/jbise.2014.74025
Abstract: Nowadays, brain function evaluation using Functional Near Infrared Spectroscopy (fNIRS) is one of the most potential non-invasive monitoring techniques. This paper concerns usefulness of the NIRS signals denoising using the Hemodynamic Evoked Response (HomER) as graphical user interface displays the NIRS data, fast independent component analysis (FASTICA) method to reduce data dimension and the combined Wavelet & PCA method for enhancing NIRS signals. NIRS signals include many types of noise, spread across a broad spectrum of frequencies, such as: low frequency noise from respiratory interference, 0.1 - 0.3 Hz, Mayer wave, about 0.1 Hz, cardiac interference, 0.8 - 2.0 Hz, and other artifacts from head and facial motions. Meanwhile, electronic components generate high frequency noise. Multi-resolution wavelet and PCA was applied successfully to enhance the NIRS signals. It consists of adaptively modifying the wavelet coefficients based on the degree of noise contamination of the processed NIRS signal. This is done subsequently to the signal pre-processing by reducing data dimension using the FASTICA method. We demonstrate, using signal-to-noise ratio and correlation indicators, that the technique used is superior to the wavelet and moving average filter and outperforms the proposed denoising NIRS signal.

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