Ali E.S.,Zagazig University
Energy | Year: 2015
This paper proposes the speed control of IM (Induction Motor) fed by wind turbine using ICA (Imperialist Competitive Algorithm). The wind turbine plays as a prime mover to a connected DC (Direct Current) generator. PWM (Pulse Width Modulation) is used to get three phase AC (Alternating Current) voltage from the output of DC generator. The proposed design problem of speed controller is established as an optimization problem. ICA is adopted to search for optimal controller parameters by minimizing the time domain objective function. The behavior of the proposed ICA has been estimated with the behavior of the conventional ZN (Ziegler-Nichols) and GA (Genetic Algorithm) in order to prove the superiority of the proposed ICA in tuning PI (Proportional plus Integral) controller. Also, the behavior of the proposed controller has been tested over a wide range of operating conditions. Simulation results confirm on the better behavior of the optimized PI controller based on ICA compared with other algorithms. © 2015 Elsevier Ltd.
Kotb E.,Zagazig University
Applied Microbiology and Biotechnology | Year: 2013
Conversion of fibrinogen to fibrin inside blood vessels results in thrombosis, leading to myocardial infarction and other cardiovascular diseases. In general, there are four therapy options: surgical operation, intake of antiplatelets, anticoagulants, or fibrinolytic enzymes. Microbial fibrinolytic enzymes have attracted much more attention than typical thrombolytic agents because of the expensive prices and the side effects of the latter. The fibrinolytic enzymes were successively discovered from different microorganisms, the most important among which is the genus Bacillus. Microbial fibrinolytic enzymes, especially those from food-grade microorganisms, have the potential to be developed as functional food additives and drugs to prevent or cure thrombosis and other related diseases. There are several assay methods for these enzymes; this may due to the insolubility of substrate, fibrin. Existing assay methods can be divided into three major groups. The first group consists of assay of fibrinolytic activity with natural proteins as substrates, e.g., fibrin plate methods. The second and third groups of assays are suitable for kinetic studies and are based on the determination of hydrolysis of synthetic peptide esters. This review will deal primarily with the microorganisms that have been reported in literature to produce fibrinolytic enzymes and the first review discussing the methods used to assay the fibrinolytic activity. © 2013 Springer-Verlag Berlin Heidelberg.
Hammad A.E.,Zagazig University
Materials and Design | Year: 2013
This work investigates the effects of small additions (0.05 and 0.1wt.%) of Ni on the microstructure and mechanical properties of low Ag content Sn-0.5Ag-0.7Cu (SAC (0507)) lead-free solder alloy. The addition of 0.05Ni resulted in the microstructural refinement, uniform distribution of the Ag3Sn and (Cu,Ni)6Sn5 intermetallic compounds (IMCs) and small primary β-Sn grains. This apparently enhances the mechanical strength and microhardness. However, the addition of 0.1Ni leads to the formation of relatively high fraction of the primary β-Sn phase and the IMCs appeared abrasive within the matrix. As a result, the SAC (0507)-0.1Ni solder exhibits low tensile strength, microhardness and large elongation, which produce a soft and highly compliant bulk solder. In addition, the strength of all studied alloys increases with increasing strain rate and decreasing testing temperature, showing strong strain rate and temperature dependence. Based on the obtained stress exponents and activation energies, it is proposed that the dominant deformation mechanism in SAC (0507) solders is dislocation climb over the whole temperature range investigated. © 2013 Elsevier Ltd.
Hammad A.E.,Zagazig University
Materials and Design | Year: 2013
For development of lead-free solder for advance electrical components, the correlation of microstructure with thermal and creep properties of novel Ni-doped Sn-0.5Ag-0.7Cu (SAC (0507)) lead free solders has been investigated. Results showed that addition of 0.05Ni into the lead-free SAC (0507) solder led to the microstructural refinement, more uniform distribution of the Ag3Sn, (Cu,Ni)6Sn5 intermetallic compounds (IMCs) and small primary β-Sn grains. However, the SAC (0507)-0.1Ni alloy has relatively high fraction of the primary β-Sn phase and the IMCs appeared coarse within the matrix compared with the other examined alloys. DSC results showed that the addition of Ni did not produce any significant effect on the melting behavior. Interestingly, 0.05wt.% Ni addition exhibited a drastically reduced undercooling to be 6.3°C. In terms of creep behavior, the SAC (0507)-0.05Ni gave the highest creep resistance due to the fine dispersion of IMCs. Furthermore, 0.05wt.% Ni addition can evidently increase the creep-rupture life, about 2.0 times greater than that of the baseline SAC (0507) and approximately 5.0 times better than that of SAC (0507)-0.1Ni solder. Meanwhile, the SAC (0507)-0.1Ni alloy shows lower creep resistance which is mainly attributable to smaller volume fraction of the precipitate phases. Based on the obtained stress exponents and activation energies, it is proposed that the dominant deformation mechanism in SAC (0507) solders is dislocation climb over the whole temperature range investigated. © 2013 Elsevier Ltd.
Ramadan M.F.,Zagazig University
Food Research International | Year: 2011
Exotic fruits play an important role in nutrition as an excellent base for low calorie and dietetic products. Highly valued for its unique flavor, texture and color, recent research has shown cape gooseberry (Physalis peruviana) to be high in many beneficial compounds. The diversity of functional applications to which P. peruviana can be put gives this fruit great importance. The food industry has used cape gooseberry in different products including beverages, yogurts and jams. With the rapidly growing popularity of this unique fruit it is important to have a comprehensive reference for its nutritional benefits. This review provides a valuable source for current knowledge on bioactive phytochemicals and further development of P. peruviana for functional foods as well as nutraceutical and pharmaceutical industries. © 2011 Elsevier Ltd.
El-Fergany A.A.,Zagazig University
IET Generation, Transmission and Distribution | Year: 2013
This article investigates the implementation of integrated evolutionary algorithms based for solving the capacitor placement optimisation problem with reduced annual operating cost. Differential evolution and pattern search (DE-PS) are used as meta-heuristic optimisation tools to solve optimal capacitor placement problem. The objective function is formulated to enhance bus voltage profiles effectively within the specified voltage constraints and reduce line active energy losses whereas maximising the benefits of installing reactive compensators. To tackle and reduce the search space process and computational CPU time, the potential buses candidate for capacitor allocations are pre-identified. At that moment, hybrid DE-PS approach is used for the estimation of required optimum level/size of shunt capacitive compensations. The overall accuracy and reliability of the developed approach were validated and tested on several radial distribution systems with different topologies and varying sizes and complexities. Computational results obtained showed that the proposed approach is capable of producing high-quality solutions, and demonstrated its viability. The results are compared with one of previous studies using recent heuristic methods. ©The Institution of Engineering and Technology 2013.
Ramadan M.F.,Zagazig University
Industrial Crops and Products | Year: 2013
The consumption of health-promoting products such as cold pressed oils may improve human health and prevent certain diseases. Blends (10% and 20%, w/w) of cold pressed oils including black cumin oil (BC), cumin oil (Cum), coriander oil (Cor) and clove oil (Clo) with high linoleic sunflower oil (SF) were formulated. Oxidative stability (OS) and radical scavenging activity (RSA) of SF and blends stored under oxidative conditions (60 °C) for 8 days were studied. By increasing the proportion of cold pressed oils in SF, linoleic acid level decreased, while tocols level increased. Progression of oxidation was followed by measuring peroxide value (PV), p-anisidine value (Av), conjugated dienes (CD) and conjugated trienes (CT). Inverse relationships were noted between PV as well as Av and OS at termination of storage. Levels of CD and CT in SF and blends increased with increase in time. Cold pressed oil blends gave about 70% inhibition of DPPH. radicals. Oxidative stabilities of oil blends were better than SF, most likely as a consequence of changes in fatty acids and tocols' profile, and minor bioactive lipids found in cold pressed oils. © 2012 Elsevier B.V.
Abu-Donia H.M.,Zagazig University
Knowledge-Based Systems | Year: 2012
Rough set theory is an important technique in knowledge discovery in databases. In covering based rough sets, many types of rough set models are established in recent years. This paper presents new types of rough set approximations using multi knowledge base, that is, family of finite number of (reflexive, tolerance, dominance, equivalence) relations by two ways. Properties and applications of these approximation operators are studied and many examples are given. © 2011 Elsevier B.V. All rights reserved.
Ali E.S.,Zagazig University
International Journal of Electrical Power and Energy Systems | Year: 2014
A new metaheuristic method, the BAT search algorithm based on the echolocation behavior of bats is proposed in this paper for optimal design of Power System Stabilizers (PSSs) in a multimachine environment. The PSSs parameter tuning problem is converted to an optimization problem which is solved by BAT search algorithm. An eigenvalues based objective function involving the damping factor, and the damping ratio of the lightly damped electromechanical modes is considered for the PSSs design problem. The performance of the proposed BAT based PSSs (BATPSS) has been compared with Genetic Algorithm (GA) based PSSs (GAPSS) and the Conventional PSSs (CPSS) under various operating conditions and disturbances. The results of the proposed BATPSS are demonstrated through time domain analysis, eigenvalues and performance indices. Moreover, the results are presented to demonstrate the robustness of the proposed algorithm over the GA and conventional one. © 2014 Elsevier Ltd. All rights reserved.
Elgindy E.A.,Zagazig University
Fertility and Sterility | Year: 2011
Objective: To identify if there are certain cutoff levels for P and or the P/E2 ratio on the day of hCG that would be defined as detrimental for occurrence of pregnancy in women with normal ovarian reserve undergoing cleavage-stage embryo transfer (ET). Secondarily, to determine if these same cutoffs might have the same potential negative effect in women undergoing blastocyst ET. Design: Prospective cohort study including two randomized cohorts. Setting: Private and university fertility centers. Participant(s): A total of 240 women undergoing long agonist protocol with at least four grade 1 day 3 embryos. Intervention(s): Women were randomized in a 1:1 ratio to undergo day 3 or day 5 embryo transfer. Main Outcome Measure(s): Clinical pregnancy rate (CPR) was the primary outcome. Result(s): Using receiver operator characteristics, cutoffs for P and P/E2 ratio were 1.5 ng/mL and 0.55, respectively. Patients with P ≤1.5 ng/mL and P/E2 ≤0.55 undergoing cleavage-stage ET had higher CPR. Using multiple regression, P/E 2 ratio was the only independent predictor for pregnancy. The P and P/E2 cutoffs were not correlated with CPR in blastocyst transfers. Conclusion(s): Progesterone >1.5 ng/mL and P/E2 >0.55 affect the CPR in women undergoing cleavage-stage, but not blastocyst ET. P/E 2 ratio is the only independent prognosticator for cycle outcome in women undergoing cleavage-stage ET. Copyright © 2011 American Society for Reproductive Medicine, Published by Elsevier Inc.