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mechanism of Silver Nanoparticles Deposition by Electrolysis and Electroless methods on a Graphite Substrate

International Journal of Nonferrous metallurgy 2022年第1期10卷 1-14页

作者： mahmoud A. Rabah nabil Nassif Girgis Chemocal and Electrochemical Treatment Lab. mineral Processing Dept. Central metallurgical Research and Development Institute (CmRDI) El-Flezzat Str. El-Tebbin Cairo Egypt Control and Surface Protection Lab (CMRDI) El-Flezzat Str. El-Tebbin Cairo Egypt

This study shows a silver electrodeposition model (EDm) on a graphite substrate. The electrolyte was a 0.01 m solution of pure silver and chromium nitrate using an electrolyzing cell. EDC with current density up to 20 mA/cm2 and 15 mV and pulse current were studied. Results revealed that silver deposited at a rate of 0.515 mg/cm2/min with 12 mA/cm2 that decreases to 0.21 and 0.16 mg/cm2·min with the decrease of current density to 6 and 5 mA/cm2 respectively. The model postulates that silver ions (a) were first hydrated before diffusing (b) from the solution bulk to the cathode vicinity, The next step (c) involved the chemical adsorption of these ions on certain accessible sites of the graphite substrate (anode), The discharged entities (d) adhere to the graphite surface by Van der Vales force. Silver ions are deposited because the discharge potential of silver is low (0.38 mV) as compared to other metal ions like chromium (0.82 mV). Pulse current controls silver deposition due to flexibility in controlling steps (a)-(c) of the deposition mechanisms. Parameters like current density, current on-time, current-off time, duty cycle (ratio of current on time and total pulse time) and pulse frequency influenced the shape and size of the deposits. Step (b) suggested that silver particles were deposited in a monolayer thickness. The silver layer turned multiple after fully satisfying the accessible sites with the monolayer. The activation energy ΔE value amounts to 86.32 kJ/mol/K. At high temperature and current density, homogeneous diffusion occurs.

关键词： Silver and Chromium Nanoparticles Electrolysis Electroless Deposition Chemical Deposition and Pulse Current Graphite Substrate

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Low Voltage Ride through Control Capability of a Large Grid Connected PV System Combining DC Chopper and Current Limiting Techniques

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Journal of Power and Energy Engineering 2019年第1期7卷 62-79页

作者： Ronald Ntare nabil H. Abbasy Karim H. m. Youssef Department of Electrical Power & machines Engineering Faculty of Engineering Alexandria University Alexandria Egypt

This paper presents the development and performance capability of a comprehensive Low voltage ride through (LVRT) control scheme that makes use of both the DC chopper and the current limiting based on the required reactive power during fault time. The study is conducted on an 8.5 mW single stage PV power plant (PVPP) connected to the Rwandan grid. In the event of fault disturbance, this control scheme helps to overcome the problems of excessive DC-link voltage by fast activation of the DC chopper operation. At the same instance, AC current is limited to the maximum rating of the inverter as a function of the injected reactive current. This helps overcome AC-over- current that may possibly lead to damage or disconnection of the inverter. The control scheme also ensures voltage support and power balance through the injection of reactive current as per grid code requirements. Selected simulations using mATLAB are carried out in the events of different kinds of fault caused voltage dips. Results demonstrate the effectiveness of the proposed LVRT control scheme.

关键词： Grid Connected Photovoltaic (PV) Power Plants (GCPSs) Voltage Dips Low Voltage Ride Through (LVRT) Grid Code (GC)

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Concordance of HER-2/Neu over Expression with Steroid Receptor Status in Female Breast Cancers

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Surgical Science 2014年第8期5卷 354-362页

作者： mohamed Salah Abdelhamid Solafa Amin abdelaziz Sahar Ali Daoud Ahmed mohamed Sadat Ayman Refaat Abdelhaseeb Tamer mohamed nabil mohamed Salah Abdelbasset Hesham Ahmed Nafady Khaled Ahmed Shawky mohamed Hasssen Abdelmoola Benisuef Faulty of medicine Benisuef Egypt Kasr Al Aini Faculty of medicine Cairo Egypt

HER-2/neu over expression is associated with increased tumor aggressiveness, increased rates of recurrence, and increased mortality in node positive patients. It is amplified and/or over expressed in approximately 30% of female breast cancers. This study was to detect the relation between HER-2/neu over expression and steroid hormone receptor status. It was conducted at Cairo and Bani Suif university hospitals between February 2012 to February 2014. HER-2/neu over expression was found to be positive in thirteen patients (41%) out of the thirty two patients included in the study, more positive (52%) HER-2/neu was found among estrogen receptor (ER) positive patients, on the other hand, only 18% positive HER-2/neu was detected among ER negative patients. This difference was statistically significant (P me outcome was with progesterone receptors (PR) and HER-2/neu with statistically significant difference also (P = 0.02). Conclusion: HER-2/neu over expression is strongly related to ER and PR, this was more evident in negative steroid receptors status. The failure of treatment in positive steroid receptors could be explained by HER-2/neu positivity.

关键词： HER-2/Neu ER PR

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Synergistic curative effect of chicory extract and cisplatin against thioacetamide-induced hepatocellular carcinoma

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Hepatoma Research 2015年第1期1卷 147-154页

作者： Hanaa A.Hassan Hanaa m.Serag nabil m.Abdel-Hamid mahmoud m.Amr Department of Zoology Division of PhysiologyFaculty of ScienceMansoura UniversityMansoura 35516Egypt Biochemistry Department Pharmacy CollegeKafr El-Sheikh UniversityKafr El-Sheikh 33516Egypt

Aim:Hepatocellular carcinoma(HCC)is the dominant form of primary liver cancer and is histologically and etiologically distinct from other forms of primary liver *** objective of this study was to elucidate the synergistic effect and the role of chicory extract[inulin(IN)]as a chemo-sensitizer for cisplatin(CIS)treatment of ***:Five groups of rats were treated for 4 *** groups consisted of the control group,a group receiving thioacetamide(TAA)(200 mg/kg b.w)in drinking water,a group injected intraperitoneally with a single dose of CIS(7.5 mg/kg b.w)in addition to TAA for 4 months,a group receiving oral doses of IN(10 mg/kg b.w)in addition to TAA for 4 months,and a group injected intraperitoneally with a single dose of CIS(7.5 mg/kg b.w)and IN(10 mg/kg b.w)plus TAA for 4 ***:The current data exhibited increment of serum and liver enzyme(alanine aminotransferase,aspartate aminotransferase,alkaline phosphatase,creatine kinase,and lactate dehydrogenase)activity,serum lipid profi le levels(total lipids,total cholesterol,triglycerides,low-density lipoprotein,and very low-density lipoprotein),and a signifi cant increase inα-fetoprotein and bilirubin,accompanied with reduced total serum protein and albumin levels in a HCC rat ***,numerous alterations were detected in hepatic tissues of HCC rats,such as lymphocytic cell infi ltration,damage of hepatocytes,dilated congested central vein with degenerated endothelial cells,and congested blood sinusoids in addition to masson’s trichrome staining blue collagen fi bers in hepatocytes and central vein indicating hepatic fi *** of HCC rats with CIS or IN improved such deleterious effects,where IN is more effective than CIS,and the best effect can be observed in rats that received both CIS and ***:It could be concluded that IN in chicory extract acts as a chemo-sensitizer to CIS for treatment in an HCC rat model.

关键词： Chicory cisplatin hepatocellular carcinoma inulin

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Time-resolved terahertz spectroscopy of charge carrier dynamics in the chalcogenide glass As_(30)Se_(30)Te_(40)[Invited]

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Photonics Research 2016年第3期4卷 22-28页

作者： Tianwu Wang Elena A.Romanova nabil Abdel-moneim David Furniss Anna Loth Zhuoqi Tang Angela Seddon Trevor Benson Andrei Lavrinenko Peter Uhd Jepsen Department of Photonics Engineering (DTU Fotonik) Technical University of Denmark Saratov State University Department of Physics Faculty of Engineering University of Nottingham

Broadband(1.6–18 THz) terahertz time-domain spectroscopy(THz-TDS) and time-resolved terahertz spectroscopy(TRTS) were performed on a 54 μm thick chalcogenide glass(As_(30)Se_(30)Te_(40)) sample with a two-color laser-induced air plasma THz system in transmission and reflection modes, respectively. Two absorption bands at 2–3 and 5–8 THz were observed. TRTS reveals an ultrafast relaxation process of the photoinduced carrier response, well described by a rate equation model with a finite concentration of mid-bandgap trap states for self-trapped *** photoinduced conductivity can be well described by the Drude–Smith conductivity model with a carrier scattering time of 12–17 fs, and we observe significant carrier localization effects. A fast refractive index change was observed 100 fs before the conductivity reached its maximum, with 2 orders of magnitude larger amplitude than expected for the optically induced THz Kerr effect, indicating that free carriers are responsible for the transient index change.

关键词： Te Invited Se Time-resolved terahertz spectroscopy of charge carrier dynamics in the chalcogenide glass As

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Concerning The Effect of Surface material on Nucleate Boiling Heat Transfer of R-113

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Journal of Electronics Cooling and Thermal Control 2011年第2期1卷 22-27页

作者： Reza Hosseini Amir Gholaminejad mahdi nabil 不详

This paper presents results of an experimental investigation carried out to determine the effects of surface material on nucleate pool boiling heat transfer of refrigerant R113. Experiments were performed on horizontal circular plates of brass, copper and aluminum. The heat transfer coefficient was evaluated by measuring wall superheat and effective heat flux removed by boiling. The experiments were carried out in the heat flux range of 8 to 200 kW/m2. The obtained results have shown significant effect of surface material, with copper providing the highest heat transfer coefficient among the samples, and aluminum the least. There was negligible difference at low heat fluxes, but copper showed 23% better performance at high heat fluxes than aluminum and 18% better than brass.

关键词： Boiling Heat Transfer R-113 Nucleate Boiling Surface material

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Association between low molecular polypeptide 7 single nucleotide polymorphism and response to therapy in hepatitis C virus infection

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World Journal of Hepatology 2013年第3期5卷 97-103页

作者： moataza H Omran Basma E Fotouh Samar S Youssef Noha E Ibrahim Wael nabil EL-Sayed m mahdy Wafaa G Shosha mostafa K El-Awady microbial Biotechnology Department Genetic Engineering Division National Research Center Chemistry Department Faculty of Science Helwan University

AIm: To investigate the relationship between low molecular polypeptide-7 (LmP-7) gene polymorphism and response to interferon (IFN) therapy in chronic hepatitis C virus (HCV) patients. mETHODS: LmP-7 polymorphism at codon 49 with nucleotide substitution from A to C was amplified in 104 chronic HCV patients of genotype 4. The amplicons were digested with restriction endonuclease Bsm I and the produced restriction fragment length polymorphism was analyzed. Patients received IFN + regional blood volume therapy for 48 wk and the frequency of thissingle nucleotide polymorphism (SNP) was statistically correlated with treatment response. The exclusion criteria for these patients were stated by the national health program for treating viral hepatitis. main exclusion criteria included co-infection with hepatitis B virus or schistosomiasis, thyroid dysfunction, uncontrolled diabetes mellitus, history of long term drug or alcohol intake and autoimmune hepatitis. multivariate analyses were done to correlate LmP-7 SNP plus several factors such as age, gender, weight, serum alpha-fetoprotein (AFP) and alanine aminotransferase levels, liver activity, fibrosis score and viral load with response to therapy. RESULTS: The data presented in this study clearly demonstrated statistically significant differences between sustained virological response (SVR) (defined as the absence of HCV RNA levels in the patient's sera at least 6 mo after discontinuation of treatment) and non-response (NR) (where HCV RNA levels in the patient's sera never become undetectable for 6 mo during or after treatment). Variables were described as odds ratio with 95%CI. The data were considered significant if P values were ≤ 0.05; highly significant if P mP-7 C/C allele were associated with SVR, while the other two genotypes C/A and A/A were associated with NR patients, 83.3% and 64.3% respectively, showing that g

关键词： Hepatitis C virus Interferon therapy Low molecular mass polypeptide Host gene Single nucleotide polymorphism

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Fabrication of Congo Red/Oxidized Porous Silicon (CR/OPS) pH-Sensors

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materials Sciences and Applications 2013年第8期4卷 79-87页

作者： Abdel-Hady Kashyout Hesham m. A. Soliman marwa nabil Ahmed A. Bishara Advanced Technology and New materials Research Institute City for Scientific Research and Technology Applications New Borg El-Arab City Alexandria Egypt Physics Department Faculty of Science Alexandria University Alexandria Egypt

The fabrication of nano porous silicon, nPSi, using alkali etching process has been studied and carried out. The surface chemistry of anisotropic etching of n-type Si-wafer is reviewed and the anisotropic chemical etching of silicon in alkaline solution using wetting agents is discussed. Transformation of crystallographic plane of n-Si (211) to nPSi (100) has occurred on using n-propanol as wetting agent. The rate of pore formation was 0.02478 - 0.02827 μm/min, which was heavily dependent upon the concentration of the etchant containing wetting agents, allowing patterned porous silicon formation through selective doping of the substrate. A particle size of 15 nm for porous nano-silicon was calculated from the XRD data. Porosity of PS layers is about 10%. Pore diameter and porous layer thickness are 0.0614 nm and 16 μm, respectively. The energy gap of the produced porous silicon is 3.3 eV. Furthermore, the combination of PS with Congo Red, which are nanostructured due to their deposition within the porous matrix is discussed. Such nano compounds offer broad avenue of new and interesting properties depending on the involved materials as well as on their morphology. Chemical route was utilized as the host material to achieve pores filling. They were impregnated with Congo Red, which gave good results for the porous silicon as a promising pH sensor.

关键词： Nano Porous Silicon Anisotropic Etching Process Alkali Etching Congo Red PH Sensor

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Cold Thermal Storage and Peak Load Reduction for Office Buildings in Saudi Arabia

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Journal of Electronic Science and Technology 2014年第1期12卷 13-19页

作者： nabil Y.Abdel-Shafi Ramzy R.Obaid Ibrahim m.Jomoah Department of Electrical and Computer Engineering King Abdulaziz University Industrial Engineering Department King Abdulaziz University

This paper the chilled water and involves the investigations of ice cold thermal storage technologies along with the associated operating strategies for the air conditioning （AC） systems of the typical office buildings in Saudi Arabia, so as to reduce the electricity energy consumption during the peak load periods. In Saudi Arabia, the extensive use of AC for indoor cooling in offices composes a large proportion of the annual peak electricity demand. The very high temperatures over long summer periods, extending tYom may to October, and the low cost of energy are the key factors in the wide and extensive use of air conditioners in the kingdom. This intense cooling load adds up to the requirement increase in the capacity of power plants, which makes them under utilized during the oil：peak periods. Thermal energy storage techniques are one of the effective demand-side energy management methods. Systems with cold storage shifts all or part of the electricity requirement from peak hours to off-peak hours to reduce demand charges and/or take advantage of off-peak rates. The investigations reveal that the cold thermal energy storage techniques are effective from both technical and economic perspectives in the reduction of energy consumption in the buildings during peak periods.

关键词： hldex Termsold thermal storage demand sidemanagement peak load reduction thermal energystorage.

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Assessment of Various Empirical Soil Loss Estimation Equations in Arid Regions

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Journal of Geoscience and Environment Protection 2022年第1期10卷 109-122页

作者： mahmoud m. Ahmed Ayman G. Awadallah nabil A. Awadallah Wael T. Ahmed Department of Civil Engineering Faculty of Engineering Fayoum University Fayoum Egypt

One of the most commonly used equations to estimate soil erosion is the revised universal soil loss equation (RUSLE). Based on the early approach developed by the Soil Conservation Service of USA, the rainfall erosivity factor (R-factor) in the RUSLE equation requires sub-daily rainfall data, which is usually not available. Other empirical equations estimate R-factor based on available rainfall data like annual and monthly rainfall data. In arid regions such as the Arabian Peninsula, several studies estimated the R-factor based on these empirical equations without calibration. We propose in this paper to assess the applicability of some of these empirical equations against R-factor values calculated using as a reference the RUSLE approach. For this data, data from 104 stations with sub-daily rainfall was collected. The reference R-factor was calculated for the 104 stations. The results of seven empirical equations were tested against the reference R-factor. Most of the tested equations significantly underestimated the R-factor. Furthermore, the obtained RMSE and MAE values were almost as high as the average R-factor, with MAPE exceeding 100%. Therefore, it is recommended not to apply these equations in arid regions. A recalibration of the form of equation that gave the best results, gave an RMSE of 280 (Mj·mm/(ha·hr)) and the mAPE dropped to 47.6%.

关键词： Soil Erosion RUSLE R-Factor Arid Region Arabian Peninsula

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