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An Optimization Approach for Unit Commitment of a Power System Integrated with Renewable Energy Sources： A Case Study of Afghanistan

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Journal of Energy and Power Engineering 2017年第8期11卷 528-536页

作者： Mohammad Masih Sediqi Masahiro Furukakoi Mohammed E. lotfy Atsushi Yona Tomonobu Senjyu Department of Electrical and Electronics Engineering University of the Ryukyus Okinawa 903-0123 Japan

This paper focused on generation scheduling problem with consideration of wind, solar and PHES （pumped hydro energy storage） system. Wind, solar and PHES are being considered in the NEPS （northeast power system） of Afghanistan to schedule all units power output so as to minimize the total operation cost of thermal units plus aggregate imported power tariffs during the scheduling horizon, subject to the system and unit operation constraints. Apart from determining the optimal output power of each unit, this research also involves in deciding the on/off status of thermal units. In order to find the optimal values of the variables, GA （genetic algorithm） is proposed. The algorithm performs efficiently in various sized thermal power system with equivalent wind, solar and PHES and can produce a high-quality solution. Simulation results reveal that with wind, solar and PHES the system is the most-cost effective than the other combinations.

关键词： Generation scheduling unit commitment renewable energy sources GA.

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埃及理想卫生系统中的五星级医生

国外医学（医学教育分册） 2000年第3期21卷 12-12,5页

作者： lotfy Dowidar 丁可

Control Scheme of Hybrid Wind-Diesel System with SMES Using NSGA-II

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Journal of Energy and Power Engineering 2017年第3期11卷 204-213页

作者： Mohammed E. lotfy Tomonobu Senjyu Mohamed A. Farahat Amal F. Abdel-Gawad Atsuhi Yona Department of Electrical Power and Machines Zagazig University Zagazig 44511 Egypt Department of Electrical and Electronics Engineering University of the Ryukyus Okinawa 903-0213 Japan

Robust control approach of hybrid wind-diesel power system is proposed in this paper. PID （proportional integral derivative） controller is designed in the blade pitch system of wind turbine to improve the system dynamic performance. Furthermore, to minimize the system oscillations, SMES （super-conducting magnetic energy storage） with first order lead-lag controller is implemented to supply and absorb active power quickly trying to reach power generation/demand balance and thereby control system frequency. Minimization of frequency and wind output power deviations are considered as two objective functions for the PID controller of wind turbine. Also, mitigating frequency and diesel output power deviations are presented as two objective functions of the lead-lag controller of SMES. NSGA-II （modified version of non-dominated sorting genetic algorithm） is used to tune the controllers＇ parameters to get an optimal response. The effectiveness and robustness of the proposed control technique are investigated under different operating conditions using Matlab environment. The simulation results confirm the ability of the controllers to damp all frequency and output powers fluctuations and enhance the stability and reliability of the hybrid power system.

关键词： Wind-diesel system isolated power system energy storage frequency control blade pitch control NSGA-II.

Network Structure-Based Critical Bus Identification for Power System Considering Line Voltage Stability Margin

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Journal of Power and Energy Engineering 2018年第9期6卷 97-111页

作者： Oludamilare Bode Adewuyi Mir Sayed Shah Danish Abdul Motin Howlader Tomonobu Senjyu Mohammed E. lotfy University of the Ryukyus 1 Senbaru Nishihara-cho Nakagami Okinawa Japan University of Hawaii Manoa Honolulu Hawaii USA Zagazig University Zagazig Egypt

Voltage security assessment of power system is an important and all-inclusive aspect of power system operation and preventive control actions. Fast and accurate detection of critical components of the power system is one essential approach for preventing the occurrence of voltage collapse phenomenon. Over the years, several approaches for voltage collapse point identification and prevention have been widely studied using the continuous power flow approach, minimum singular value of eigenvalues, Jacobian matrices, and power transfer concept. In this work, critical node (bus) identification based on power system network structure is proposed. In this approach, the power system is treated as a multidimensional graph with several nodes (buses) linked together by the transmission lines. An improved line voltage stability margin estimator which is based on active and reactive power changes in a power system is used as the weight of each transmission line and an adaptation of the degree of centrality approach is used to determine the criticality of the system buses. A comparative analysis with other bus voltage stability indices is presented to test the suitability of the proposed approach using the IEEE 14, 30, 57 and 118 bus test systems.

关键词： Voltage Stability Voltage Collapse Critical Node Critical Boundary Index Centrality Measure

A Study on Quark-Gluon Plasma Equation of State Using Generalized Uncertainty Principle

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Journal of Modern Physics 2013年第4期4卷 13-20页

作者： Nabil M. El Naggar lotfy I. Abou-Salem Ibrahim A. Elmashad Ahmed Farag Ali Physics Department Faculty of Science Benha University Benha Egypt

The effects of Generalized Uncertainty Principle, which has been predicted by various theories of quantum gravity replacing the Heisenberg’s uncertainty principle near the Planck scale, on the thermodynamics of ideal Quark-Gluon Plasma (QGP) consisting of two and three flavors are included. There is a clear effect on thermodynamical quantities like the pressure and the energy density which means that a different effect from quantum gravity may be used in enhancement the theoretical results for Quark-Gluon Plasma state of matter. This effect looks like the technique used in lattice QCD simulation. We determine the value of the bag parameter from fitting lattice QCD data and a physical interpretation to the negative bag pressure is introduced.

关键词： Generalized Uncertainty Principle

Ultrafine Fraction and Aerosol Attached Activity Size Distribution of Radon Progeny in Living Room

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Journal of Physical Science and Application 2012年第7期2卷 205-215页

作者： Amer Mohamed Mohamed Moustafa lotfy Abd EI-Hady Mona Moustafa Mahmoud Mostafa Yuness Abd El Fatah Department of Physics Faculty of Science Minia University Minia Egypt

Inhalation of 222Rn progeny in the domestic environment contributes the greatest fraction of the natural radiation exposure to the public. The ultrafine activity of these progeny amounts up to about l 0 percent of the total activity （attached and ultrafine）, but is considered to yield about 50 percent of the total radiation dose. Therefore, measurements of ultrafine fraction are essential for the estimation of radiation dose. The current study presents measured data on the total equilibrium equivalent concentration （EEC） and ultrafine equilibrium equivalent concentration （EECUn）, ultrafine fraction （fb）, attached and unattached activity size distributions of radon progeny in the low ventilated rooms at Minia University, Minia city, Egypt. A screen diffusion battery was used for collection the ultrafine fraction and measuring the total activity concentration of radon progeny. The attached activity size distribution of 214pb is determined by using a low pressure cascade impactor. The EEC of radon progeny varied between 1.3 and 18.9 Bq/m3 with a mean value of 5.2 ± 0.48 Bq/m2. The mean activity thermodynamic diameter （AMTD） ofultrafine of radon progeny was determined to be 1.26 nm with relative mean geometric standard deviations （GSD） of 1.3. The ultrafine fraction of radon progeny, fb, has a range 0.01 to 0.21 with an average of 0.08 ± 0.03. A relative mean GSD of 2.7 was determined for attached 2Lapb at a mean active median aerodynamic diameter （AMD） of 350 nm. Based on the above experimental results, the deposition fractions have been evaluated in each air way generation through the human lung by applying a lung deposition model. The bronchial deposition efficiencies of particles in the size range of attached radon progeny were found to be lower than those of ultrafine progeny. The effect of radon progeny deposition by adult male has been also studied for various levels of physical exertion. The dose conversion factor has been discussed as a function of fb.

关键词： Aerosol radon progeny activity size distribution ultrafine fraction and attached fraction.

A Comparative Study of the Novel Ratio Difference Method versus Conventional Spectrophotometric Techniques for the Analysis of Binary Mixture with Overlapped Spectra

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American Journal of Analytical Chemistry 2012年第11期3卷 761-769页

作者： Hayam M. lotfy Sarah S. Saleh Nagiba Y. Hassan Samia M. Elgizawy Analytical Chemistry Department Faculty of Pharmacy Assuit University Assuit Egypt Analytical Chemistry Department Faculty of Pharmacy Cairo University Cairo Egypt Analytical Chemistry Department Faculty of Pharmacy October University for Modern Sciences and Arts (MSA) 6th October City Egypt

The smart novel ratio difference spectrophotometric method was developed and validated for the determination of a binary mixture of Sodium cromoglicate (SCG) and Fluorometholone (FLU) in presence of benzalkonium chloride without prior separation. The results were compared to that of the conventional methods (dual wavelength and first derivative of ratio spectra). The suggested methods were validated in compliance with the ICH guidelines and were successfully applied for determination of SCG and FLU in their laboratory prepared mixtures and commercial ophthalmic solution. The novel method showed significant advantages over the conventional methods regarding simplicity, minimal data manipulation and maximum reproducibility and robustness;which enabled the analysis of binary mixtures with overlapped spectra for routine quality control testing with quite satisfactory.

关键词： Ratio Difference Sodium Cromoglicate Fluorometholone Binary Mixtures Spectrophotometry

Correlation between Serum Uric Acid Level and Left Ventricular Ejection Fraction in Patients with Congestive Heart Failure

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World Journal of Cardiovascular Diseases 2019年第11期9卷 857-866页

作者： Mohamed A. W. Ezzat Ahmed M. Boghdady Kassem F. A. Ibrahim lotfy H. Abo Dahab Internal Medicine and Cardiology Department Faculty of Medicine Sohag University Sohag Egypt

Background: One of the risk factors of congestive heart failure that still under investigations is hyperuricemia. It’s still debatable whether it’s an independent risk factor or it’s just a consequence of other disorders associated with cardiovascular diseases like hypertension, diabetes and dyslipidemia. Objective: The aim of our study is to elucidate whether in patients with heart failure serum uric acid level correlates with left ventricular ejection fraction supporting the possibility that the detection of progressive hyperuricemia in these patients may be an indicator of deteriorating cardiac function. Methods: We conducted a prospective study that included 124 studied patients and 26 apparently healthy persons at Coronary care unit and Internal Medicine Department at Sohag University Hospitals. Studied populations were classified into;* Group “I”: newly diagnosed heart failure, * Group “II”: decompensated heart failure on regular treatment, * Group “III”: decompensated heart failure but stopped their treatment from three months, Group “IV”: control group, healthy and age-matched subjects. We studied the association between left ventricular ejection fraction, the severity of congestive heart failure and the serum uric acid levels and the well-known conventional risk factors. Results: The main finding was the significantly higher mean serum uric acid levels in patients with congestive heart failure versus apparently healthy persons with “P value = 0.02”. When we adjusted the serum uric acid with other significant risk factors in the univariate analysis which were age, gender and smoking, serum uric acid was an independent risk factor “P value = 0.04”. There was a significant correlation between serum uric acid level and the severity of congestive heart failure “P value 0.35”. High rates of serum uric acid levels were recorded in patients with reduced ejection fraction. A uric acid level of 8.45 mg/dl was found to be the most appropriate cut-off point with the se

关键词： Uric Acid Level Congestive Heart Failure

Pancreas-protective effects of chlorella in STZ-induced diabetic animal model: insights into the mechanism

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Journal of Diabetes Mellitus 2011年第3期1卷 36-45页

作者： Amr Amin Mohamed lotfy Doaa Mahmoud-Ghoneim Ernest Adeghate Mohamed A. Al-Akhras Maryam Al-Saadi Salam Al-Rahmoun Rasheed Hameed Biology Department UAE University Physics Department Faculty of Science UAE University Department of Zoology Faculty of Science Cairo University Biophysics Department Faculty of Science Cairo University

The aim of this study is to examine the effect of intragastric administration of chlorella (1 g/kg body weight) for a period of 30 days to treat normal and diabetic male Wistar rats. Diabetes was induced by intraperitoneal injection of streptozotocin (STZ) (60 mg/kg - 1 body weight). A significant (p < 0.05) reduction of blood glucose level in diabetic chlorella-treated rats was observed compared to diabetic untreated. Chlorella increased the number of glutathione-positive cell in diabetic rats compared to untreated diabetics. Chlorella administration increased the percentage of insulin secreting pancreatic beta cells both in normal and diabetic treated rats. Percentage of glucagon producing alpha cells of the pancreas were reduced both in normal and diabetic chlorella-treated rats. Chlorella-induced regenerative ability on pancreas was mediated by up-regulation of Ki67 and down-regulation of P53 and by its potent anti-oxidant ability. The present results suggest that chlorella may play an important role in improving the overall condition of diabetic patients and delay its complication by restoring the function of pancreatic insulin-secreting cells.

关键词： Chlorella Diabetes Glucose Insulin Beta Cells.