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Eid Ahmad M.,Lee Hyun-Woo,Nakaoka Mutsuo The Korean Institute of Power Electronics 2006 JOURNAL OF POWER ELECTRONICS Vol.6 No.4
Various methods have been discussed to reduce detent force in a tubular permanent magnet type linear single phase AC generator. In particular, the proposed methods depend on variations of the permanent magnet construction. These methods include two approaches in the form of sloped magnets, and conical magnets in addition to the conventional method of optimizing the magnet length. The undesired detent force ripples were calculated by a two dimensional Finite Element Method (FEM). Moreover, the generated electromotive force in the stator coils was calculated for each configuration of the permanent magnet. The experimental results agreed well with those obtained from the FEM-based simulations. Sufficient reduction in the detent force was achieved over the range of 40% while the root mean square of the output voltage was maintained. It was found that sloping the permanent magnet decreased the detent force and at the same time increased the generated rms voltage of the AC generator. The performance of the designed linear AC generator was evaluated in terms of its efficiency, total weight, losses, and power to weight ratio.
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Eid, R.,Dancygier, A.N. Techno-Press 2005 Structural Engineering and Mechanics, An Int'l Jou Vol.21 No.6
This paper presents a theoretical model for the behavior of partially confined axi-symmetric reinforced concrete members subjected to axial load. The analysis uses the theories of elasticity and plasticity to cover the full range of the concrete behavior. Analysis of the elastic range of the problem involves boundary conditions that are defined along a relatively simple geometry. However, extending the analysis into the plastic range involves difficulties that arise from the irregular geometry of the boundary between the plastic zone and the elastic zone, a boundary which is also changing as the axial load increases. The solution is derived by replacing the discrete steel ties with an equivalent tube of thickness $t_{eq}$ and by analyzing the concrete cylinder, which is uniformly confined by the equivalent tube. The equivalency criterion initiates from a theoretical analysis of the problem in its elastic range where further finite element analysis shows that this criterion is valid also for the plastic range of the cylinder material. According to the proposed model, the efficiency of the lateral reinforcement can be evaluated by the equivalent thickness $t_{eq}$. Comparison with published test results of confined reinforced concrete stress-strain curves shows good agreement between the test and the analytical results.
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Characterization and Performance Evaluation of Advanced Aircraft Electric Power Systems
Eid, Ahmad,El-Kishky, Hassan,Abdel-Salam, Mazen,El-Mohandes, Mohamed T. The Korean Institute of Power Electronics 2010 JOURNAL OF POWER ELECTRONICS Vol.10 No.5
A model of an advanced aircraft electric power system is developed and studied under variable-speed constant-frequency (VSCF) operation. The frequency of the generator's output voltage is varied from 400-Hz to 800-Hz for different loading scenarios. Power conversions are obtained using 12-pulse power converters. To reduce the harmonic contents of the generator output waveforms, two high-pass passive filters are designed and installed one at a time at the generator terminals. The performance of the two passive filters is compared according to their losses and effectiveness. The power quality characteristics of the studied VSCF aircraft electric power system are presented and the effectiveness of the proposed filter is demonstrated through compliance with the newly published aircraft electrical standards MIL-STD-704F.
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Mostafa Eid,Saleh Kaytbay,Ahmed El‑Assal,Omayma Elkady 대한금속·재료학회 2022 METALS AND MATERIALS International Vol.28 No.11
Poor interfacial structure and severe agglomerations of carbon fiber (CF) are significant problems that face carbon fiberreinforced aluminium (CF/Al) composites. Thus, CF was surface modified with nano copper particles (Cu) to overcomethese problems. Two groups of CF/Al composites (uncoated and coated) at different weight percentages of reinforcement(0, 5, 10, 15, and 20) were fabricated using the planetary ball milling method and then uniaxially hot coined at 550 ℃ under700 MPa. The results showed that CF refined the crystallite size of the Al matrix, and no Al4C3 or Al2Cu were detected inXRD patterns. The density and thermal expansion of composites reduced with increasing CF percentage in all samples. The electrical and thermal conductivities are improved up to 10 wt% of uncoated reinforcement and 15 wt% of coated one. The mechanical test results revealed that by increasing CF, the compressive strength of composites decreased while thewear properties improved for both groups. Cu deposition on CF improved the bonding between reinforcement and matrix,producing composites with better interfacial bonding, fewer agglomerations and porosity, and higher values of the propertiesof the composites.
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Stability of Thin Shell Wormholes in Born-Infeld Theory Supported by Polytropic Phantom Energy
Ali Eid 한국물리학회 2017 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.70 No.4
In the framework of the Darmois-Israel formalism, the dynamical equations of motion of spherically-symmetric thin-shell wormholes supported by a polytropic phantom energy in Einstein- Born-Infeld theory are constructed. A stability analysis of the spherically-symmetric thin-shell wormhole by using the standard potential method is carried out. The existence of stable, static solutions depends on the values of some parameters.
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CaCO3–CO2–H2O system in falling film on a bank of horizontal tubes: Model verification
Aiman Eid Al-Rawajfeh 한국공업화학회 2010 Journal of Industrial and Engineering Chemistry Vol.16 No.6
The purpose of this work is to model the CaCO3–CO2–H2O system in falling film on a bank of horizontal tubes. The model was applied on a 5-effects reference thermal vapor compression multiple-effect distiller (MED-TVC) operating at top brine temperatures (TBT) of 60–70 8C. The model can predict pH values, CaCO3 deposition and fouling resistance with greater accuracy. Through the MED stages, the HCO3 and CO2 concentrations slightly increased while the CO32 concentration slightly decreased. The pH decreased from 8.8 in the first stage to 8.4 in the 5th stage. The CO2 release rates as well as the CaCO3deposition rates increase with increasing top brine temperature (TBT). CO2 release rates decrease from 36.4 g/t feed water in the first stage to 32.5 g/t in the last stage. The specific CaCO3 deposition decreases from 127.3 g/t feed water in the first stage to 100.1 g/t in the last stage. 2010 The Korean Society of Industrial and Engineering Chemistry. Published by Elsevier B.V. All rights reserved.
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Genome editing: the road of CRISPR/Cas9 from bench to clinic
Ayman Eid,Magdy M Mahfouz 생화학분자생물학회 2016 Experimental and molecular medicine Vol.48 No.-
Molecular scissors engineered for site-specific modification of the genome hold great promise for effective functional analyses of genes, genomes and epigenomes and could improve our understanding of the molecular underpinnings of disease states and facilitate novel therapeutic applications. Several platforms for molecular scissors that enable targeted genome engineering have been developed, including zinc-finger nucleases (ZFNs), transcription activator-like effector nucleases (TALENs) and, most recently, clustered regularly interspaced palindromic repeats (CRISPR)/CRISPR-associated-9 (Cas9). The CRISPR/Cas9 system’s simplicity, facile engineering and amenability to multiplexing make it the system of choice for many applications. CRISPR/Cas9 has been used to generate disease models to study genetic diseases. Improvements are urgently needed for various aspects of the CRISPR/Cas9 system, including the system’s precision, delivery and control over the outcome of the repair process. Here, we discuss the current status of genome engineering and its mplications for the future of biological research and gene therapy.
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Brima, Eid I. Asian Pacific Journal of Cancer Prevention 2016 Asian Pacific journal of cancer prevention Vol.17 No.10
Objective: The use of Shamma (smokeless tobacco) by certain groups is giving rise to health problems, including cancer, in parts of Saudi Arabia. Our objective was to determine metals levels in Shamma using inductively coupled plasma mass spectrometry (ICP-MS). Methods: Thirty-three samples of Shamma (smokeless tobacco) were collected, comprising four types: brown Shamma (n = 14.0), red Shamma (n = 9.0), white Shamma (n = 4.0), and yellow Shamma (n = 6.0). All samples were collected randomly from Shamma users in the city of Najran. Levels of 11 elements (Al, As, Cd, Co, Cr, Cu, Li, Mn, Ni, Pb, and Zn) were determined by ICP-MS. Results: A mixed standard (20 ppb) of all elements was used for quality control, and average recoveries ranged from 74.7% to 112.2%. The highest average concentrations were found in the following order: Al ($598.8-812.2{\mu}g/g$), Mn ($51.0-80.6{\mu}g/g$), and Ni ($23.2-53.3{\mu}g/g$) in all four Shamma types. The lowest concentrations were for As ($0.7-1.0{\mu}g/g$) and Cd ($0.0-0.06{\mu}g/g$). Conclusions: The colour of each Shamma type reflects additives mixed into the tobacco. Cr and Cu were showed significant differences (P < 0.05) among Shamma types. Moreover, Pb levels are higher in red and yellow Shamma, which could be due to use (PbCrO4) as yellow colouring agent and lead tetroxide, Pb3O4 as a red colouring agent. The findings from this study can be used to raise public awareness about the safety and health effects of Shamma, which is clearly a source of oral exposure to metals.
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