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Process Simulation of a 620 Mw-Natural Gas Combined Cycle Power Plant with Optimum Flue Gas Recirculation

Open Journal of Energy Efficiency 2018年第2期7卷 33-52页

作者： Ahmed Badr Al Hashmi Abdel Aziz Abdulla mohamed Zin Eddine Dadach Chemical & Petroleum Engineering Department Abu Dhabi Men’s College Higher Colleges of Technology Abu Dhabi UAE

The main objective of this investigation is to obtain an optimum value for the flue gas recirculation ratio in a 620 MW-Natural Gas Combined Cycle (NGCC) power plant with a 100% excess air in order to have a composition of the exhaust gas suitable for an effective absorption by amine solutions. To reach this goal, the recirculated flue gas is added to the secondary air (dilution air) used for cooling the turbine. The originality of this work is that the optimum value of a Flue Gas Recirculation (FGR) ratio of 0.42 is obtained from the change of the slope related to the effects of flue gas recirculation ratio on the molar percentage of oxygen in the exhaust gas. Compared to the NGCC power plant without flue gas recirculation, the molar percentage of carbon dioxide in the flue gas increases from 5% to 9.2% and the molar percentage of oxygen decreases from 10.9% to 3.5%. Since energy efficiency is the key parameter of energy conversion systems, the impact of the flue gas recirculation on the different energy inputs and outputs and the overall efficiency of the power plant are also investigated. It is found the positive effects of the flue gas recirculation on the electricity produced by the steam turbine generator (STG) are more important than its cooling effects on the power output of the combustion turbine generator (CTG). The flue gas recirculation has no effects on the water pump of the steam cycle and the increase of energy consumed by the compressor of flue gas is compensated by the decrease of energy consumed by the compressor of fresh air. Based on the Low heating value (LHV) of the natural gas, the flue gas recirculation increases the overall efficiency of the power plant by 1.1% from 57.5% from to 58.2%.

关键词： Natural Gas Combined Cycle (NGCC) Flue Gas Recirculation Absorption by Amine CCS

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Adsorption of Silver Nanoparticles from Aqueous Solution by Multiwalled Carbon Nanotubes

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Advances in Nanoparticles 2017年第2期6卷 22-32页

作者： Dalia M. A. Hassan mohamed R. F. Farghali Department of Animal Hygiene Faculty of Veterinary Medicine Assiut University Assiut Egypt

Silver nanoparticles (AgNPs) are becoming an emerging pollutant of the environment. In this study, the efficacy of Multiwalled carbon nanotubes (MWCNTS) to remove AgNPs from aqueous solution at a concentration of 250 and 500 mg/100 ml MWCNTS was investigated. The results showed that the adsorption of AgNPs by 250 and 500 mg/100 ml MWCNTS after a contact time of 10 min., 30 min., 60 min., 120 min. and 240 min was 33.95%, 34.36%, 40.32%, 45.33%, 58.53% and 57.29%, 61.27%, 64.89%, 87.21%, 88.58%, respectively. The statistical analysis of data showed that, after adding 250 and 500 mg/100 ml MWCNTS, the total residues of AgNPs were significantly reduced in all MWCNTS exposed samples when compared to the control groups (P < 0.05). Moreover, at the two used concentrations, there were significant differences between 240 min. and all other contact times. The result concluded that the removal percent of AgNPs from aqueous solution was increased with the increase in contact time and concentrations of MWCNTS. Additionally, MWCNTS are expected to be potential adsorbent in the future due to their high removal capacity of nano-sized silver.

关键词： Silver Nanoparticles Multiwalled Carbon Nanotubes Adsorption Water Treatment

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Entanglement Quantifier Based on Atomic Wehrl Entropy for Non-Linear Interaction between a Single Two-Level Atom and SU(1,1) Quantum System

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Journal of Quantum Information Science 2014年第1期4卷 44-53页

作者： Sayed Abdel-Khalek Manal Al-Quthami mohamed M. A. Ahmed Mathematics Department Faculty of Science Taif University Taif KSA

In this paper, we study the dynamics of the atomic inversion, scaled atomic Wehrl entropy and marginal atomic Wehrl density for a single two-level atom interacting with SU(1,1) quantum system. We obtain the expectation values of the atomic variables using specific initial conditions. We examine the effects of different parameters on the scaled atomic Wehrl entropy and marginal atomic Wehrl density. We observe an interesting monotonic relation between the different physical quantities for different values of the initial atomic position and detuning parameter.

关键词： Scaled Atomic Wehrl Entropy Atomic Q-Function Atomic Inversion

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Detection of Hypoglycemic and Antidiabetic Fraction in Ethanol Extract of <i>Jatropha curcas</i>Aerial Parts

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Pharmacology & Pharmacy 2014年第7期5卷 663-669页

作者： mohamed Farag Adnan Al-Rehaily Mohammad Shamim Ahmad Ramzi Ahmed Mothana Pharmacognosy Department Faculty of Pharmacy King Saud University Riyadh Saudi Arabia Pharmacognosy Department Faculty of Pharmacy King Saud University Riyadh Saudi Arabia Pharmacognosy Department Faculty of Pharmacy Sana’a University Sana’a Yemen

Diabetes is a global problem and many efforts are being done all over the world searching for new drugs that can manage it more efficiently. The World Health Organization recommended the natural products to be possible source for antidiabetic compounds. Jatropha curcas plant was employed in Indian traditional medicine for the treatment of several disorders. So, hexane, chloroform and ethanolic extracts of the aerial part were subjected for evaluation of their hypoglycemic and antidiabetic effects. Oral administration of ethanolic extract at a dose of 400 mg/kg showed hypoglycemic and antidiabetic activities in alloxan induced diabetic mice. Bioassay-guided fractionation used to isolate the active fraction. Moreover, the drug was found to be safe up to dose of 5 g/kg. Further fractionation is recommended to find the active compound(s).

关键词： Herbal Medicine Jatropha curcas Hypoglycemic Effect Antidiabetic Effect Active Fraction

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Cassava Groundnut Intercropping: A Sustainable Land Management Practice for Increasing Crop Productivity and Organic Carbon Stock on Smallholder Farms

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Agricultural Sciences 2023年第1期14卷 73-87页

作者： Keiwoma M. Yila mohamed S. Lebbie Abdul R. Conteh mohamed S. Kamara Lamin I. Kamara Mathew L. S. Gboku Njala Agricultural Research Centre Sierra Leone Agricultural Research Institute Freetown Sierra Leone Department of Food Security and Livelihood Action against Hunger Sierra Leone Mission Freetown Sierra Leone Faculty of Agricultural and Natural Resources Management Ernest Bai Koroma University of Science and Technology Makeni Campus Makeni Sierra Leone Headquarters Sierra Leone Agricultural Research Institute Freetown Sierra Leone

Cassava-groundnut intercropping is not a common practice among smallholder farmers in Sierra Leone even though both crops are well suited for intercropping. On-farm trials were conducted in three locations (Bai Largor, Bassah, and Njala Kanima) in the Moyamba district during the 2021 cropping season to investigate the efficacy of cassava-groundnut intercropping for increasing crop productivity and soil organic carbon stock on smallholder farms in the Moyamba district, Southern Sierra Leone. The experimental design was a randomized complete block design in three replications with treatments of sole groundnut, sole cassava and cassava-groundnut intercropping. Data on the yield and yield components of cassava and groundnut were analysed using the PROC MIXED procedure of SAS 9.4 and means were compared using the standard error of difference (SED). The above-ground biomass, number of roots per plant, and fresh root yield of cassava were not significantly (p > 0.05) affected by the cassava-based cropping system. Averaged across locations, intercropping cassava with groundnut decreased the above-ground biomass, the number of roots per plant, and fresh root yield of cassava by 17%, 11%, and 17%, respectively. The above-ground biomass, number of pods per plant and fresh pod yield of groundnut were significantly (p 1), the highest net revenue and benefit-cost ratio. The benefit-cost ratio was also favourable for the sole cassava (BCR > 1) but not favourable for the sole groundnut (BCR eld loss for the cassava and groundnut, the benefit-cost ratio was favourable (1.12) only for the cassava groundnut intercropping system. The net soil organic carbon stock was favourable only for the cassava-groundnut intercrop. Averaged across locations, the net soil organic carbon for the cassava-gro

关键词： Benefit-Cost Ratio Cassava-Groundnut Intercropping Land Equivalent Ratio Soil Organic Carbon Sustainable Land Management

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3D-Analysis of Soil-Foundation-Structure Interaction in Layered Soil

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Open Journal of Civil Engineering 2014年第4期4卷 373-385页

作者： Mohd Ahmed Mahmoud H. mohamed Javed Mallick Mohd Abul Hasan Civil Engineering Department Faculty of Engineering King Khalid University Abha KSA

The analysis of building structure in contact with soil involves an interactive process of stresses and strains developed within the structure and the soil field. The response of Piled-Raft Foundation system to the structure is very challenging because there is an important interplay between the component of building structure and the soil field. Herein, soil-foundation-structure interaction of buildings founded on Piled-Raft Foundation is evaluated through 3D-Nonlinear Finite element Analyses using PLAXIS3D FOUNDATION code. The soil settlements and forces demand of the high-rise building structures and foundation is computed. The parametric study affecting the soil-foundation-structure response has been carried out. The parameters such as construction phasing, sequential loading, building aspect ratios, soil failure models and thickness proportion of soil field stiff layer, are considered. It is concluded that the interaction of building foundation-soil field and super-structure has remarkable effect on the structure.

关键词： Foundation Piled-Raft Foundation Soil Models Soil Field Finite element Method Sequential Loading Construction Phase

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滥竽充数何时了?——我们必须抵制劣质研究的泛滥

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世界教育信息 2010年第9期23卷 88-90页

作者： Mark Bauerlein mohamed Gad-el-Hak Wayne Grody Bill McKelvey Stanley W. Trimble 覃云云（译）埃默里大学英语系弗吉尼亚联邦大学机械工程学加州大学洛杉矶分校医学加州大学洛杉矶分校管理学加州大学洛杉矶分校地理学不详

毋庸置疑，科学研究对于一个国家的健康发展、兴旺繁荣和安全保障都是必不可少的。然而，在众多关于科研价值的讨论中，很少有人提出到底出版多少研究成果是最好的。当人们在为科研遭受资金短缺影响而出现困难倍感遗憾时，我们不应忽略... 详细信息

毋庸置疑，科学研究对于一个国家的健康发展、兴旺繁荣和安全保障都是必不可少的。然而，在众多关于科研价值的讨论中，很少有人提出到底出版多少研究成果是最好的。当人们在为科研遭受资金短缺影响而出现困难倍感遗憾时，我们不应忽略的事实是：过去几十年中，研究发现和成果层出不穷。

关键词：抵制科研价值研究成果科学研究安全保障资金短缺

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Antiboitic Resistance of Uropathogenic Eshcherichia coli in Pateints of Hargeisa Group Hospital, Hargeisa, Somaliand

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Advances in Microbiology 2022年第5期12卷 333-342页

作者： Hassan mohamed Abdi Mukhtar Ismail Hassan Helmy elsayed Abdulaziz Nadira Harir Omer Department of Microbiology Hargeisa Group Hospital Hargeisa Somaliland Department of Microbiology Faculty of Medical Laboratory Science Haldoor Medical University Hargeisa Somaliland

Background: Urinary tract infection is a common disease in Somaliland society. The predominant causative organism of Urinary tract infection is Escherichia coli. This research studies antibiotic resistance of uropathogenic E. coli in patients of Hargeisa Group Hospital. The study selected commonly prescribed antibiotics for urinary tract infection treatment. Methodology: Urine samples of patients were cultured to isolate causative organisms of the urinary tract infection. Chromo-agar media, CLED, and biochemical tests are applied to identify the type of bacteria. Antibiotic reactions to E. coli bacteria are measured to differentiate between sensitive and resistant drugs with the guidance of the Clinical and Laboratories Standard Institute (CLSI). Kirby Bauer disc diffusion method is applied to assess antimicrobial activity against E. coli. Data of patients such as age, sex, symptoms of UTI, previous UTI infection, and history of antibiotic use were recorded. SPSS and Microsoft Excel are applied to analyze and interpret data. Results: The predominant organism that caused urinary tract infection was Escherichia coli (55%), Klebsiella spp (15%), Candida spp (15%), Enterococcus spp (10%), Staph spp 2.5%, and Pseudomonas spp 2.5% while other 55% were negative. The study assessed antibiotic resistance of E. coli, which reported resistance to Tetracycline at (70%), Ampicillin (64%), and Cotrimoxazole (61%). The bacteria showed moderate resistance to Ceftriaxone (43.5%), Nalidixic acid (43%), and Ciprofloxacin (36%). The bacteria are sensitive to Amikacin (100%), Nitrofurantoin (96%), Levofloxacin (73%) and gentamicin (74%). Conclusion: The overall incidence of antibiotic resistance to E. coli is high because the bacteria show a percentage of resistance to each antibiotic except Amikacin which gives (100%) sensitivity. The research recommends public awareness of the risks associated with antibiotic use and periodic evaluation of antibiotic resistance to accomplish better ma

关键词： Urinary Tract Infection Escherichia coli Antibiotics Resistant Sensitive Multiple Drug Resistant (MDR)

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A Study of the Factors Affecting Transporting Solid— Liquid Suspension through Pipelines

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Open Journal of Fluid Dynamics 2013年第3期3卷 152-162页

作者： A. I. Abd Al Aziz H. I. mohamed Public Authority of Applied Education & Training Kuwait Kuwait

An experimental investigation was carried out on the transport of solid liquid mixture through pipelines. The principal aim of this was to study how to transport slurries through pipeline systems. The experimental tests include measurements of main parameters affecting transport of solid liquid mixture, like sand slurry and mud slurry. These parameters are deduced by applying non-dimensional approach, which includes Reynolds number, Froude number, concentration, specific gravity, and ratio of particle to pipe diameter. Preliminary results include the following general trends: 1) Increasing input concentration increases the pressure gradient, whereas decreases the efficiency of solid transport;2) As specific gravity of solid material increases, the pressure gradient increases and the efficiency of transport decreases;3) As mixture velocity increases, the efficiency of transport increases;4) Solids with fine grain size are preferred than with coarse grain size from the view points of pressure gradient and efficiency of transport. Also, the present experimental data has been compared with the correlations developed before by different authors. Such correlations relate the pressure gradient to flow velocity, specific gravity, and efficiency of transport to grain size of solid material, and input solid concentration.

关键词： Sand Slurry Solid Concentration Pressure Gradient Efficiency of Transport Solid Diameter

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Utilization of Amaranth Flour in Preparation of High Nutritional Value Bakery Products

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Food and Nutrition Sciences 2020年第5期11卷 336-354页

作者： Seham Yehia Gebreil Maha Ibrahim Kamal Ali Esraa Ahmed mohamed Mousa Department of Crops Technology Research Food Technology Research Institute Agricultural Research Center Giza Egypt Department of Special Food and Nutrition Food Technology Research Institute Agricultural Research Center Giza Egypt

Amaranth has become an unconventional crop that interesting of scientists and researchers due to its unique nutritional properties, in addition to bear the water lack and be suitable for all types of soil. The objective of this study was to utilize amaranth flour in preparation of high nutritional value bakery products, crackers and tortilla produced by using amaranth flour instead of corn flour (w/w) by 0%, 25%, 50%, 75% and 100% levels substitution. The prepared products were evaluated for its chemical composition, minerals content, amino acids composition, fatty acid composition, color analysis, biological active compounds analysis and sensory evaluation. Results showed that substitution with amaranth flour increased protein, fat, ash and fiber. As for minerals and amino acid, it indicated that the formula No. 3 (25% corn flour/75% amaranth flour) in crackers and the formula No. 2 (50% corn flour/50% amaranth flour) in tortilla contained higher amount of minerals such as iron, calcium, potassium, zinc, magnesium, manganese, copper and phosphorus, and of the essential amino acids such as Leucine, Lysine and valine. On the other hand the formula No. 3 in crackers had the highest unsaturated fatty acids content and lowest of total saturated fatty acids content. While the formula No. 2 in tortilla had the highest saturated fatty acids content and lowest of unsaturated fatty acids content. The results also showed that the incorporation of amaranth flour in the preparation of the crackers and tortilla led to significantly decreased yellowness and lightness compared with control. Also, results indicated that crackers and tortilla which prepared with amaranth flour exhibited higher antioxidant activity than control formulas. Concerning sensory evaluation of crackers, results showed significant decrease in appearance, color and overall acceptability while, tortilla had significant decrease in general appearance, color and total score at all formulas. Based on the results

关键词： Amaranth High Nutritional Value Crackers Tortilla Nutritional Benefits

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