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Laser Surface Hardening of Tool Steels—Experimental and Numerical Analysis

Journal of Surface Engineered Materials and Advanced Technology 2013年第2期3卷 146-153页

作者： abdel-Monem El-Batahgy Ramadan ahmed Ramadan abdel-rahman Moussa Manufacturing Technology Department Central Metallurgical R & D Institute Cairo Egypt Mechanical Engineering Department Faculty of Engineering Helwan University Helwan Egypt. Spare Parts Sector Egyptian Iron and Steel Company Helwan Egypt

This research work is focused on both experimental and numerical analysis of laser surface hardening of AISI M2 high speed tool steel. Experimental analysis aims at clarifying effect of different laser processing parameters on properties and performance of laser surface treated specimens. Numerical analysis is concerned with analytical approaches that provide efficient tools for estimation of surface temperature, surface hardness and hardened depth as a function of laser surface hardening parameters. Results indicated that optimization of laser processing parameters including laser power, laser spot size and processing speed combination is of considerable importance for achieving maximum surface hardness and deepest hardened zone. In this concern, higher laser power, larger spot size and lower processing speed are more efficient. Hardened zone with 1.25 mm depth and 996 HV surface hardness was obtained using 1800 W laser power, 4 mm laser spot size and 0.5 m/min laser processing speed. The obtained maximum hardness of laser surface treated specimen is 23% higher than that of conventionally heat treated specimen. This in turn has resulted in 30% increase in wear resistance of laser surface treated specimen. Numerical analysis has been carried out for calculation of temperature gradient and cooling rate based on Ashby and Easterling equations. Then, surface hardness and hardened depth have been numerically estimated based on available Design-Expert software. Numerical results indicated that cooling rate of laser surface treated specimen is high enough to be beyond the nose of the CCT diagram of the used steel that in turn resulted in a hard/martensitic structure. Numerically estimated values of surface temperature, surface hardness and hardened depth as a function of laser processing parameters are in a good agreement with experimental results. Laser processing charts indicating expected values of surface temperature, surface hardness and hardened depth as a function of different wider range of laser processing par

关键词： High Speed Tool Steels Laser Surface Hardening Ashby and Easterling Heat Transfer Equations Design Expert Software Laser Processing Charts

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Positional effect of mutations in 5'UTR of hepatitis C virus 4a on patients' response to therapy

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World Journal of Gastroenterology 2009年第12期15卷 1480-1486页

作者： Mostafa K El Awady Hassan M Azzazy ahmed M Fahmy Sherif M Shawky Noha G Badreldin Samar S Yossef Moataza H Omran abdel rahman N Zekri Said A Goueli Department of Biomedical Technology National Research CenterDokkiCairo 12622Egypt Department of Chemistry and Yousef Jameel Science and Technology Research Center the American University in CairoCairo 11511Egypt Structural biology department Free University of AmsterdamDe Boelelaan 10851081 HV AmsterdamThe Netherlands National Cancer Institute Cairo 11796Egypt Department of Pathology and Laboratory Medicine University of WisconsinMadisonWI 53711United States

AIM:To investigate the effects of mutations in domain Ⅲ of the hepatitis C virus(HCV)internal ribosome entry sequences(IRES)on the response of chronic HCV genotype 4a patients to interferon therapy.METHODS:HCV RNA was extracted from 19 chronic HCV 4a patients receiving interferon/ribavirin therapy who showed dramatic differences in their response to combination therapy after initial viral clearance.IRES domainⅢ was cloned and 15 clones for each patient were sequenced.The obtained sequences were aligned with genotype 4a prototype using the ClustalW program and mutations scored.Prediction of stem-loop secondary structure and thermodynamic stability of the major quasispecies in each patient was performed using the MFOLD 3.2 program with Turner energies and selected constraints on base pairing.RESULTS:Analysis of RNA secondary structure revealed that insertions in domainⅢ altered WatsonCrick base pairing of stems and reduced molecular stability of RNA,which may ultimately reduce binding affinity to ribosomal proteins.Insertion mutations in domainⅢwere statistically more prevalent in sustained viral response patients(SVR,n=14)as compared to breakthrough(BT,n=5)patients.CONCLUSION:The influence of mutations within domainⅢ on the response of HCV patients to combination therapy depends primarily on the position,but not the frequency,of these mutations within IRES domain Ⅲ.

关键词：丙型肝炎病毒基因型治疗反应插入突变位置效应慢性丙型肝炎 RNA提取持续病毒应答二级结构

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3D Multi-gate Transistors： Concept, Operation, and Fabrication

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Journal of Electrical Engineering 2015年第1期3卷 1-14页

作者： Nader Shehata abdel-rahman Gaber ahmed Naguib Ayman E. Selmy Hossam Hassan Ibrahim Shoeer Omar Ahmadien Rewan Nabeel Department of Engineering Mathematics and Physics Faculty of Engineering Alexandria University Alexandria 21544 Egypt CSNP (Center of Smart Nanotechnology and Photonics) Smart CI Research Center Alexandria University Alexandria 21544Egypt Department of Electrical Engineering Faculty of Engineering Alexandria University Alexandria 21544 Egypt School of Sciences and Engineering the American University in Cairo P.O. Box 74 New Cairo 11835 Egypt

The multi-gate transistors such as Fin-FETs, Tri-gate FETs, and Gate-all-around (GAA) FETs are remarkable breakthrough in the electronic industry. 3D Transistor is taking the place of the conventional 2D planar transistor for many reasons. 3D transistors afford more scalability, energy efficient performance than planar transistors and increase the control on the channel region to reduce the short channel effect, which enables us to extend Moore"s law to further extent. In this paper, we will present a review about their structure, operation, types and fabrication.

关键词：电气工程电气测试集中参数频率

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Seasonality in the occurrence of two lepidopterous olive pests in Egypt

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Insect Science 2011年第5期18卷 565-574页

作者： Esmat M. Hegazi Maria A. Konstantopoulou Annette Herz Wedad E. Khafagi Essam Agamy Sania Showiel Atwa Atwa Gehan M. Abd EI-aziz Safaa M. abdel-rahman Faculty of Agriculture University of Alexandria Egypt Chemical Ecology and Natural Products Laboratory NCSR ＂Demokritos Ag. Paraskevi Athens Greece Federal Biological Research Centre for Agriculture and Forestry Institute for Biological Control Darmstadt Germany Plant Protection Research Institute Sabahia Alexandria Egypt Faculty of Agriculture Cairo University Cairo Egypt Plant Protection Research Institute Cairo Egypt Central Laboratory of Pesticides Alexandria Egypt

Prays oleae Bern, （OM） andPalpita unionalis Hfib., （JM） are two of the most important pests in olive groves in Egypt. A 3-year monitoring study using sex pheromone traps in semi-arid and arid olive groves was performed. In the semi-arid grove, flight pattern of the OM was the same as in other Mediterranean countries, but in dates concordating plant phenology. The moth completes three generations annually： the first flight is in March to April, the second is in May to June and the third occurs in August to October. In the arid olive grove, an interesting flight pattern was observed. First flight was always very close or overlapped with the second one with no male catches during August to October. However, eggs were present most of the season, indicating unusually high female presence and oviposition activity of the OM during the absence of males in the traps. Generally, moth densities were significantly lower in low fruiting years than in higher ones and were also lower in the arid olive grove than in the semi-arid one. In contrast, JM males were present all season, exhibiting six to seven and three to four overlapping flight peaks in arid and semi-arid olive groves, respectively. Moth densities were significantly higher in the arid olive grove than those in the semi-arid one. This study shows that trapping location and fruit beating year are characteristics that strongly affect the grove-specific information needed to estimate correctly adult emergence and thus the timing of control measures.

关键词： egg-laying activity monitoring olive growing areas Palpita unionalis Prays oleae sex pheromone

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Early detection of hepatocellular carcinoma co-occurring with hepatitis C virus infection: A mathematical model

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World Journal of Gastroenterology 2016年第16期22卷 4168-4182页

作者： abdel-rahman Nabawy Zekri Amira Salah El-Din Youssef Yasser Mabrouk Bakr Reham Mohamed Gabr Ola Sayed ahmed Mostafa Hamed Elberry ahmed Mahmoud Mayla Mohamed Abouelhoda Abeer A Bahnassy Molecular Virology and Immunology Unit Cancer Biology Department National Cancer Institute Cairo University Systems and Biomedical Engineering Department Faculty of Engineering Cairo University Center for Informatics Sciences Nile University Sheikh Zayed City Pathology Department National Cancer Institute Cairo University

AIM: To develop a mathematical model for the early detection of hepatocellular carcinoma(HCC) with a panel of serum proteins in combination with α-fetoprotein(AFP).METHODS: Serum levels of interleukin(IL)-8, soluble intercellular adhesion molecule-1(s ICAM-1), soluble tumor necrosis factor receptor Ⅱ(s TNF-RⅡ), proteasome, and β-catenin were measured in 479 subjects categorized into four groups:(1) HCC concurrent with hepatitis C virus(HCV) infection(n = 192);(2) HCV related liver cirrhosis(LC)(n = 96);(3) Chronic hepatitis C(CHC)(n = 96); and(4) Healthy controls(n = 95). The R package and different modules for binary and multi-class classifiers based on generalized linear models were used to model the data. Predictive power was used to evaluate the performance of the model. Receiver operating characteristic curve analysis over pairs of groups was used to identify the best cutoffs differentiating the different groups. RESULTS: We revealed mathematical models, based on a binary classifier, made up of a unique panel of serum proteins that improved the individual performance of AFP in discriminating HCC patients from patients with chronic liver disease either with or without cirrhosis. We discriminated the HCC group from the cirrhotic liver group using a mathematical model(-11.3 + 7.38 × Prot + 0.00108 × s ICAM + 0.2574 ×β-catenin + 0.01597 × AFP) with a cutoff of 0.6552, which achieved 98.8% specificity and 89.1% sensitivity. For the discrimination of the HCC group from the CHC group, we used a mathematical model [-10.40 + 1.416 × proteasome + 0.002024 × IL + 0.004096 × s ICAM-1 +(4.251 × 10-4) × s TNF + 0.02567 ×β-catenin + 0.02442 × AFP] with a cutoff 0.744 and achieved 96.8% specificity and 89.7% sensitivity. Additionally, we derived an algorithm, based on a binary classifier, for resolving the multi-class classification problem by using three successive mathematical model predictions of liver disease status. CONCLUSION: Our proposed mathematical model may be a useful method for the early detection of different

关键词： Mathematical model Hepatocellular carcinoma α-fetoprotein Soluble intercellular adhesion molecule-1

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

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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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Endoscopic Third Ventriculostomy versus Ventriculo-Peritoneal Shunt for Infant Hydrocephalus

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Open Journal of Modern Neurosurgery 2020年第2期10卷 193-202页

作者： Khaled Ismail abdel-aziz Radwan Nouby Mahmoud ahmed Thabet Mohammad Fekry Elshirbiny Department of Neurosurgery Faculty of Medicine Aswan University Aswan Egypt Department of Neurosurgery Faculty of Medicine Assiut University Assiut Egypt

Introduction: Patients with hydrocephalus, which is the most pediatric neurological disorder, undergo Cerebrospinal fluid (CSF) diversion through third ventriculostomy or ventriculo-peritoneal shunt. Up to date, the optimal hydrocephalus treatment modality is not clear. Aim: We compared the outcome of endoscopic third ventriculostomy (ETV) versus ventriculo-peritoneal shunt (VP shunt) as a second surgical intervention in management of Infant hydrocephalus concerning success rate and complications. Patients and Methods: We conducted an observational study of 52 children with hydrocephalus (congenital or acquired) in whom CSF diversion was performed using either ETV or VP shunt in randomized control trial. Results: During the period examined, 52 children, 26 underwent ETV and 26 underwent VP shunt. The mean age was 11.0 ± 4.3 months in ETV and 11.3 ± 4.7 months in VP shunt. Postoperative infection in the ETV group was lower than in the VP shunt group (23.1% vs. 53.8% P = 0.045). Regarding operating time, In ETV group operation duration was 46.9 min and 64.3 min in the V-P shunt group (P = 0.13). There was no statistically significant difference between the two study groups regarding the rate of obstruction, change in occipital frontal circumference (OFC) or the need of revision surgery. One year survival for VP shunt group vs. ETV group was 46.2% vs. 65.4% respectively. Conclusion: ETV associated with lower rates of postoperative infection and shorter operation time with no significant difference in rates of obstruction, change in OFC and revision surgery in comparison to VP shunt.

关键词： ETV VPS Pediatric Hydrocephalus

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Correlation of Invasively Estimated Left Ventricular End Diastolic Pressure with Acceleration of E’ Wave by Tissue Doppler Imaging of Mitral Annulus

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World Journal of Cardiovascular Diseases 2019年第9期9卷 681-691页

作者： Mahmoud Kamel Morad Beshay Said Shalaby ahmed Emara Mohammed abdel rahman Cardiology Department Faculty of Medicine Menoufia University Menoufia Egypt

Background: There is no single noninvasive index that provides a direct measure of LV filling pressure. However, invasive measuring of LV end diastolic pressure (LVEDP) provides reliable assessment of LV diastolic dysfunction, but its invasive nature limits its use in daily practice. Accurate noninvasive assessment of LV diastolic dysfunction is highly desirable, and the relationship between the degree of LVEDP and acceleration of E’ wave obtained by tissue Doppler imaging (TDI) of mitral annulus is not clearly assessed;here in our study we aimed to assess the relation between the degree of LVEDP and the acceleration rate of E’ wave of mitral annular Doppler tissue. Patients and Methods: The study included 60 patients divided equally into 3 groups according to the degree of LVEDP, group I (Normal): ’ ratio and E’ wave acceleration rate. Coronary angiography and left sided heart catheterization and measuring LVEDP were performed for correlating E’ wave acceleration rate with invasively estimated LVEDP.?Results: There was significant progressive decrease in E’ acceleration rate (E’ Acc rate) with progressive increase in LVEDP from I to III (P 0.001), while there was significant progressive increase in E/E’ ratio with progressive increase in LVEDP from I to III (P 0.003). Peak E’ acceleration rate had a significant negative correlation with LVEDP in all three groups, with p value of 0.003, 0.044 and 0.021 respectively in group I, II & III. Regarding E/E’ ratio there was a significant positive correlation in predicting normal and elevated LVEDP with p value (0.001 and 0.006) respectively while there was a non-significant correlation between E/E’ and LVEDP within grey zone group. Conclusion: E’ acceleration rate could be used as a reliable index to assess LVEDP.

关键词： LV End Diastolic Pressure E Annular Wave Acceleration

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The Antiviral Efficacy of Withania somnifera(Ashwagandha) against Hepatitis C Virus Activity: In Vitroand in SilicoStudy

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Advances in Microbiology 2020年第9期10卷 463-477页

作者： Dina Mofed Wafaa ahmed abdel-rahman Zekri Ola Said Mohamed Rahouma ahmed Hassan Ibrahim Faraag Biochemistry and Molecular Biology Unit Department of Cancer Biology National Cancer Institute Cairo University Cairo Egypt Immunity and Virology Unit Department of Cancer Biology National Cancer Institute Cairo University Cairo Egypt Department of Surgical Oncology National Cancer Institute Cairo University Cairo Egypt Department of Botany and Microbiology Faculty of Science Helwan University Cairo Egypt

Objective: Evaluation antiviral effects of Withania somnifera (Ashwagandha) leaf extract against HCV. Methods: cell proliferation was assessed using MTT assay after isolation of lymphocyte cells and treated with Ashwagandha water extract (ASH-WX) (6.25 mg/ml - 100 mg/ml). Assessment of quantitative Real-time PCR, Colony forming assay, TNF-α and molecular docking studies after infection of normal lymphocyte cells with 1 ml (1.5 × 106 HCV) serum then incubated with ASH-WX at concentration 25 mg/ml & 50 mg/ml. Results: MTT assay revealed a significant increase (p α significantly decreased following ASH-WX treatment compared with control untreated infected cells (p 3 IU/mL. Colony formation assay test revealed colony formation reduction compared to positive untreated control. Molecular docking analysis revealed good prediction of binding between Ashwagandha and NS5B and PKN2 compared to Sovaldi. Conclusion: ASH-WX may be a powerful antiviral against HCV infection.

关键词： Antiviral Ashwagandha Hepatitis C Virus Docking Lymphocyte

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DETECTION OF SINUSOIDAL SIGNALS IN FREQUENCY DOMAIN

DETECTION OF SINUSOIDAL SIGNALS IN FREQUENCY DOMAIN

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2006 CIE International Conference on Radar

作者： Fathy M.ahmed Khairy A.Elbarbary abdel rahman H.Elbardawiny Military Technical College CairoEgypt

Periodogram is a simple and efficient way to detect and estimate parameters of sinusoidal signals.In this paper,we evaluate the detection performance of the periodogram and its variants such as Bartlett,Welch methods,and a proposed Bartlett-based method.Performance evaluation through the Receiver Operating Characteristics （ROCs） of the mentioned methods are presented and compared.Previous studies showed that,the standard periodogram used to give the best detection performance.In the present work,analytical derivation and simulation results showed that,the proposed method gives a better detection performance outperforming the standard periodogram at the expense of tolerable reduction of the frequency resolution.

关键词： Detection Periodogram Bartlett FFT.

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