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Particuology 2017年第5期15卷 61-69页

作者： m. helal uddin Charles J. Coronella Department of Chemical and materials Engineering University of Nevada Reno NV 89557 USA

Numerical simulations of gas-solid fluidized beds based on the kinetic theory of granular flow exhibit a significant dependence on domain discretization. Bubble formation, bubble size and shape all vary greatly with the discretization, and the use of an inappropriate scale resolution leads to inaccurate predictions of fluidization hydrodynamics. In this study, grid-independent solutions of the two fluid model were examined by comparing the bed expansions obtained from numerical simulations with experimental results and empirical predictions, based on bubbling fluidized beds of Geldart B particles. Grid indepen- dence was achieved with a grid resolution equal to 18 times the particle diameter. The simulation results were compared with previously published data for verification purposes. The results of this work should provide a guideline for choosing the appropriate grid size and thereby minimize the time and expense associated with large simulations.

关键词： mesh effectHydrodynamicsComputational fluid dynamicsEuler-Euler method mFIX

A new approach for fuel injection into a solar receiver/ reactor:Numerical and experimental investigation

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Frontiers of Chemical Science and Engineering 2018年第4期12卷 683-696页

作者： m helal uddin Nesrin Ozalp Jens Heylen Cedric Ophoff mechanical and Industrial Engineering Department University of Minnesota DuluthDuluthMN 55812-3042USA mechanical Engineering Department 3001 LeuvenBelgium

An innovative and efficient design of solar receivers/reactors can enhance the production of clean fuels via concentrated solar energy. This study presents a new jet-type burner nozzle for gaseous feedstock injection into a cavity solar receiver inspired from the combustion technology. The nozzle design was adapted from a combustion burner and successfully implemented into a solar receiver and studied the influence of the nozzle design on the fluid mixing and temperature distribution inside the solar receiver using a 7 kW solar simulator and nitrogen as working fluid. Finally, a thorough computational fluid dynamics (CFD) analysis was performed and validated against the experimental results. The CFD results showed a variation of the gas flow pattern and gas mixing after the burner nozzle adaptation, which resulted an intense effect on the heat transfer inside the solar receiver.

关键词： solar reactor nozzle CFD heat transfer mixing and recirculation Clean fuels solar receivers nozzles Fuel injection computational fluid dynamics Heat transfer charge flow devices combustion technology mixing of gases FLOW PATTERNS

Regulating microstructure and composition by carbonizing in-situ grown metal-organic frameworks on cotton fabrics for boosting electromagnetic wave absorption

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Nano Research 2024年第8期17卷 7290-7300页

作者： Jie Jin Hongsen Long Hu Liu Yan Guo Tiantian Bai Ben Bin Xu mohammed A.Amin Hua Qiu mohamed H.helal Chuntai Liu Changyu Shen Zeinhom m.El-Bahy Zhanhu Guo State Key Laboratory of Structural Analysis Optimization and CAE Software for Industrial EquipmentNational Engineering Research Center for Advanced Polymer Processing TechnologyZhengzhou UniversityZhengzhou 450002China China State Key Laboratory of Powder metallurgy Central South UniversityChangsha 410000China School of Electronic Engineering North China University of Water Resources and Electric PowerZhengzhou 450046China Complex Conditions of High-end Tire Technology Innovation Center Shuguang Rubber Industry Research&Design Institute Co.LtdGuilin 541004China Integrated Composites Lab Department of Mechanical and Civil EngineeringNorthumbria UniversityNewcastle Upon TyneNE18STUK Department of Chemistry College of ScienceTaif UniversityP.O.Box 11099Taif 21944Saudi Arabia Shaanxi Key Laboratory of macromolecular Science and Technology School of Chemistry and Chemical EngineeringNorthwestern Polytechnical UniversityXi’an 710072China Department of Chemistry Faculty of Arts and ScienceNorthern Border UniversityRafha 73213Saudi Arabia Department of Chemistry Faculty of ScienceAl-Azhar UniversityNasr City 11884CairoEgypt

High-temperature carbonized metal-organic frameworks(mOFs)derivatives have demonstrated their superiority for promising electromagnetic wave(EmW)absorbers,but they still suffer from limited EmW absorption capacity and narrow *** the advantage of microstructure and chemical composition regulation for the design of EmW absorber,hierarchical heterostructured moS_(2)/CoS_(2)-Co_(3)O_(4)@cabonized cotton fabric(CF)(mCC@CCF)is prepared by growing ZIF-67 mOFs onto CF surface,chemical etching,and *** from the dual loss mechanism of magnetic-dielectric multicomponent carbonized mOFs,chemical etching and carbonization process can effectively introduce abundant micro-gap structure that can result in better impedance matching and stronger absorption capacity via internal reflection,doped heteroatoms(mo,N,S)to supply additional dipolar polarization loss,and numerous heterointerfaces among moS_(2),CoS_(2),Co_(3)O_(4),and CCF that produce promoted conduction loss and interfacial polarization ***,a minimal reflection loss of−52.87 dB and a broadest effective absorption bandwidth of 6.88 GHz were achieved via tunning the sample thickness and filler loading,showing excellent EmW absorption *** research is of great value for guiding the research on mOFs derivatives based EmW absorbing materials.

关键词： metal-organic frameworks hierarchical structure chemical etching sulfurization electromagnetic wave absorption

Epidemiological and histopathological characteristics of thyroid carcinoma in a Tunisian health care center

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World Journal of Otorhinolaryngology-Head and Neck Surgery 2024年第1期10卷 37-42页

作者： maissa Ben Thayer Fatma Khanchel Imen helal Dorra Chiboub Hedhli Raoueh Ehsen Ben Brahim Raja Jouini Aschraf Chadli-Debbiche Faculty of medicine of Tunis Tunis El Manar UniversityTunisTunisia Depatment of Pathology Habib Thameur's HospitalTunisTunisia Department of Otorhinolaryngology-Head and Neck surgery Habib Thameur's HospitalTunisTunisia

Background:Thyroid carcinoma(TC)accounts for almost 0.5%–1%of total *** incidence is increasing rapidly *** studies have drawn up the epidemiological profile of TC and its clinical and pathological ***,to date,no similar studies have been conducted in ***:To establish an epidemiological profile of TC in a Tunisian health care institute and to analyze its clinical and histopathological characteristics in our *** and methods:We present a retrospective study reviewing the cases of TC diagnosed in our institution in a 4-year ***:We collected a sample of 192 cases of *** consisted of 31 males and 161 females(83.8%)with a sex-ratio m/F of *** mean age was 46.4 *** thyroid carcinoma was the most frequent histological *** multifocality rate was 33.8%.The mean size of TC was 2.2±1.9 cm.60.9%of TC were staged pT1 and 20.3%had nodal *** thyroid microcarcinomas were noted in 37.5%of ***:Our results were consistent with those of the literature.A high proportion of pT1 and pN0 tumors were noted in our series,suggesting that TC's diagnosis and management was performed at an early stage of the disease in our *** addition,our study enabled us to notice the impact of the Coronavirus disease 19 crisis on the management of TC in our *** studies are needed to establish the epidemiological profile of TC in Tunisia and to assess its clinical and pathological features.

关键词： coronavirus disease 19 epidemiology papillary thyroid carcinoma papillary thyroid microcarcinoma pathology thyroid carcinoma

Biochemical Liver Functions and molecular Identification of Fasciola hepatica from Experimentally Infected Rat model

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Open Journal of Animal Sciences 2024年第2期14卷 88-100页

作者： Omnia m. Kandil Emad B. Ata margarita P. Gabrashanska Hatem A. Shalaby Tamer H. Abd El-Aziz Noha m. F. Hassan Soad m. Nasr mohamed A. helal Ebtesam m. Al-Olayan Department of Parasitology & Animal Diseases Veterinary Research Institute National Research Centre Giza Egypt Institute of Experimental morphology Pathology and Anthropology with Museum Bulgarian Academy of Sciences Sofia Bulgaria Department of Zoology Collage of Science King Saud University Riyadh Saudi Arabia

The current study was performed to evaluate the liver function status as well as molecular characterization of the recovered worms in rats experimentally infected with F. hepatica. Sixteen male Wister rats aged 30 days were randomly allocated into two groups (n = 8). The first group was infected orally with 15 viable encysted metacercaria of F. hepatica per animal. The other group was kept non-infected (control group). At zero time (before infection), the 2nd, 4th, 6th, 8th, 10th, 12th and 14th weeks post-infection (WPI), blood and serum samples were collected via puncture of retro-orbital plexus of veins from each rat. Serum enzyme level (AST and ALT) and total protein were measured, and the serum protein profile was carried out using agarose gel electrophoresis. During the period of the experiment, serum ALT and AST activities and serum total globulins significantly increased while serum total proteins and albumin markedly decreased in the infected group. On the 14th WPI, the data of the electropherogram showed that globulin fractions (α1-, β- and γ-globulin) levels were significantly increased while α2-globulin was markedly decreased in the infected group. The molecular analysis confirmed the amplification of the ITS1, ITS2 and NDI genes of F. hepatica recovered from the infected liver of rats with amplicon sizes of 630, 510 and 560 bp, respectively. Sequencing of the amplified ITS gene resulted in the determination of 3 strains (PP108836, PP108837, and PP108838). Also, analysis of the ITS2 gene resulted in obtaining 3 isolates under the accession numbers (PP109065, PP109066, and PP109067). In conclusion, fasciolosis in the rat model is suitable for routine experimental infections and caused a pronounced liver dysfunction with discharging of the Fasciola eggs in the faeces and the development of adult stages in the bile ducts. Furthermore, molecular techniques are a sensitive

关键词： Fasciola hepatica Liver Functions Serum Enzymes Serum Protein Electrophoresis molecular Characterization

Stability analysis solutions of the nonlinear modified Degasperis-Procesi water wave equation

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Journal of Ocean Engineering and Science 2017年第3期2卷 155-160页

作者： m.A.helal Aly R.Seadawy m.Zekry mathematics Department Faculty of ScienceCairo UniversityGizaEgypt mathematics Department Faculty of ScienceTaibah UniversityAl-UlaSaudi Arabia mathematics Department Faculty of ScienceBeni-Suef UniversityEgypt

In the present study,the solitary wave solutions of modified Degasperis-Procesi equation are *** the standard Degasperis-Procesi equation,where multi-peakon solutions arise,the modification caused a change in the characteristic of these peakon solutions and changed it to bell-shaped *** using the extended auxiliary equation method,we deduced some new soliton solutions of the fourthorder nonlinear modified Degasperis-Procesi equation with constant *** solutions include symmetrical,non-symmetrical kink solutions,solitary pattern solutions,weiestrass elliptic function solutions and triangular function *** discuss the stability analysis for these solutions.

关键词： modified Degasperis-Procesi water wave equation Extended auxiliary equation method Solitary wave solutions

Efficacy evaluation of the protein isolated from Peganum harmala seeds as an antioxidant in liver of rats

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Asian Pacific Journal of Tropical medicine 2013年第4期6卷 285-295页

作者： Amel m Soliman helal S Abu-El-Zahab Gamiaa A Alswiai Zoology Department Faculty of ScienceCairo University Zoology Department Faculty of Science

Objective:To evaluate the curative effect of the 132 KD protein isolated from the seeds of Peganum harmala（***） L against carbon tetrachloride（CCl4） induced oxidative stress in ***:Animals were post treated intraperitoneally with 132 KO isolated protein at doses of 4 and 8 mg/kg body weight and bovine serum albumin（BSA）（8 mg/kg body weight） as well as vitamin C（250 mg/kg body weight p.o.） for 7 d after they challenged with CCl4 orally（1 ml/Ag body weight） in olive oil（50%） for 2 ***:The purified protein from seeds of *** plant showed in vitro antioxidant activity with DPPH *** of CCl4 induced induction in serum aminotransferases（AST,ALT）,alkaline phosphatase（ALP）,lipid profile parameters and liver malondialdehyde（mDA） and decrease in serum total protein,liver superoxide dismutase （SOD）,catalase（CAT）,and reduced glutathione（GSH） levels.132 KD protein treatment of rats post CCl4 intoxication successfully alleviated the toxic effects of CCl4.Conclusions:The isolated protein possessed strong antioxidant activity comparable to that of BSA（negative control） and vitamin C（positive control）.

关键词： Carbon tetrachloride Peganum harmala Oxidative stress 132 KD isolated protein

Simulation of ion beam extraction and focusing system

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Chinese Physics C 2011年第1期35卷 83-87页

作者： B.A.Soliman m.m.Abdelrahman A.G.helal F.W.Abdelsalam Accelerators & Ion Sources Department Nuclear Research CenterEgyptian Atomic Energy Authority P.O.Box:13759 InchasAtomic EnergyCairoEgypt

The characteristics of ion beam extraction and focused to a volume as small as possible were investigated with the aid of computer code SImION 3D version 7. This has been used to evaluate the extraction characteristics （accel-decel system） to generate an ion beam with low beam emittance and high brightness. The simulation process can provide a good study for optimizing the extraction and focusing system of the ion beam without any losses and transported to the required target. Also, a study of a simulation model for the extraction system of the ion source was used to describe the possible plasma boundary curvatures during the ion extraction that may be affected by the change in an extraction potential with a constant plasma density meniscus.

关键词： ion beam emittance plasma meniscus space charge argon ion trajectories

Voltage imbalance mitigation in an active distribution network using decentralized current control

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Protection and Control of modern Power Systems 2023年第2期8卷 68-84页

作者： Ahmed m.m.Nour Ahmed A.helal magdi m.El-Saadawi Ahmed Y.Hatata Alexandria Higher Institute of Engineering and Technology(AIET) AlexandriaEgypt Department of Electrical and Control Engineering Arab Academy for Science and Technology and Maritime TransportAlexandriaEgypt Department of Electrical Engineering Faculty of EngineeringMansoura UniversityMansouraEgypt Department of Electrical Engineering College of EngineeringShaqra UniversityShaqraKingdom of Saudi Arabia

Voltage imbalance(VI)is caused by the difference in connected single-phase load or generation in a low voltage distribution network(DN).VI increase in a smart distribution grid is due to the current practice of increasing single-phase distributed generators such as photovoltaic(PV)*** paper proposes a decentralized control method to mitigate VI using distributed batteries included in smart grid interfaced residential PV *** mitigate VI using the batteries in this way,five challenges must be overcome,i.e.,equalizing all battery stress currents within the DN,mitigating VI in abnormal conditions such as signal loss among bus controllers,being immune from the distorted feedback measurements,minimizing the steady-state error at different loads,and overcoming the insufficient number or capacity of the distributed batteries at the same *** fuzzy logic controllers(FLC)are proposed at each bus to overcome these five tasks based on a decentralized control *** proposed decentralized control based on FLC is compared with centralized control based on a PI *** proposed control method is tested and verified using simulations in the mATLAB/Simulink software,and the results validate the ability of the scheme to alleviate VI on a smart distribution network under both normal and abnormal conditions.

关键词： Fuzzy controller Distributed batteries Decentralized control Voltage imbalance Distributed PV

mechanical and thermodynamical stability of BiVO4 polymorphs using first-principles study

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Chinese Physics B 2017年第3期26卷 395-403页

作者： A K m Farid UI Islam md Nurul Huda Liton H m Tariqul Islam md Al helal md Kamruzzaman Department of Computer Science and Engineering Begum Rokeya University Rangpur Rangpur-5400 Bangladesh Department of Physics Begum Rokeya University Rangpur Rangpur-5400 Bangladesh Department of Chemistry Begum Rokeya University Rangpur Rangpur-5400 Bangladesh Department of Physics and materials Science and Center of Super-Diamond and Advanced Films (COSDAF) City University of Hong Kong Hong Kong SAR China

First principles calculations of structural, electronic, mechanical, and thermodynamic properties of different poly- morphs of BiVO4 are performed using Bender-type plane/wave ultrasoft pseudopotentials within the generalized gradient approximation （GGA） in the flame of density functional theory （DFT）. The calculated structural and electronic properties are consistent with the previous theoretical and experimental results. The electronic structures reveal that m-BiVO4, op- BiVO4, and st-BiVO4 have indirect band gaps, on the other hand, zt-BiVO4 has a direct band gap. From the DOS and mulliken＇s charge analysis, it is observed that only m-BiVO4 has 6s2 Bi lone pair. Bond population analysis indicates that st-BiVO4 shows a more ionic nature and a similar result is obtained from the elastic properties. From the elastic prop- erties, it is observed that st-BiVO4 is more mechanically stable than the others, st-BiVO4 is more ductile and useful for high electro-optical and electro-mechanical coupling devices. Our calculated thermodynamic properties confirm the similar characteristics found from electronic and elastic properties, m-BiVO4 is useful as photocatalysts, solid state electrolyte, and electrode and other polymorphs are applicable in electronic device fabrications.

关键词： BiVO4 crystal structure lone pair mechanical stability