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Journal of Thermal Science 2004年第4期13卷 315-320页

作者： A. THAKKER m.el. hemry Wave Energy Research Team Department of mechanical and Aeronautical Engineering University of Limerick IrelandWave Energy Research Team Department of Mechanical and Aeronautical Engineering University of Limerick Ireland

The objective of this paper is to present the performance comparison of 2D Computational Fluid Dynamics (CFD) analysis with experimental analysis of 0.6 m impulse turbine with fixed guide vanes for both 0.6 and 0.7 hub to tip ratio (H/T). Also the comparison of 2D CFD analysis of the said turbine with different values of H/T ranging from 0.5 to 0.7. A 2D-cascade model was used for CFD analysis while uni-directional steady flow was used for experimental analysis. The blade and guide vane geometries are based on 0.6 m rotor diameter, with optimum profile, and different H/T of 0.5, 0.6 and 0.7. It was concluded from 2D CFD analysis that 0.5 H/T ratio performances was higher than that of 0.6 and 0.7 H/T at peak efficiency and the operational flow range for 0.5 H/T was found to be wider than that of 0.6 and 0.7 H/T ratio.

关键词： wave energy impulse turbine computational fluid dynamics (CFD).

Advanced Functional electromagnetic Shielding materials:A Review Based on micro‑Nano Structure Interface Control of Biomass Cell Walls

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Nano-micro Letters 2025年第1期17卷 98-134页

作者： Yang Shi mingjun Wu Shengbo Ge Jianzhang Li Anoud Saud Alshammari Jing Luo mohammed A.Amin Hua Qiu Jinxuan Jiang Yazeed m.Asiri Runzhou Huang Hua Hou Zeinhom m.el.Bahy Zhanhu Guo Chong Jia Kaimeng Xu Xiangmeng Chen Co‑Innovation Center of Efficient Processing and Utilization of Forest Resources College of Materials Science and EngineeringNanjing Forestry UniversityNanjing 210037People’s Republic of China State Key Laboratory of Efficient Production of Forest Resourced Beijing Forestry UniversityQinghua East Road 35Haidian DistrictBeijing 100083People’s Republic of China Department of Physics Faculty of Sciences‑ArarNorthern Border UniversityArar 91431Saudi Arabia Department of Chemistry College of ScienceTaif UniversityP.O.Box 1109921944 TaifSaudi Arabia Shaanxi Key Laboratory of macromolecular Science and Technology School of Chemistry and Chemical EngineeringNorthwestern Polytechnical UniversityXi’anShaanxi 710072People’s Republic of China Integrated Composites Lab Department of Mechanical and Construction EngineeringNorthumbria UniversityNewcastle Upon Tyne NE18STUK College of materials Science and Engineering Taiyuan University of Science and TechnologyTaiyuan 030024People’s Republic of China Department of Chemistry Faculty of ScienceAl-Azhar UniversityNasr CityCairo 11884Egypt Yunnan Provincial Key Laboratory of Wood Adhesives and Glued Products International Joint Research Center for Biomass MaterialsSouthwest Forestry UniversityKunming 650224People’s Republic of China School of Science Henan Agricultural UniversityZhengzhou 450002People’s Republic of China

Research efforts on electromagnetic interference(EmI)shielding materials have begun to converge on green and sustainable biomass *** materials offer numerous advantages such as being lightweight,porous,and *** to their porous nature,interfacial compatibility,and electrical conductivity,biomass materials hold significant potential as EmI shielding *** concerted efforts on the EmI shielding of biomass materials have been reported,this research area is still relatively new compared to traditional EmI shielding *** particular,a more comprehensive study and summary of the factors influencing biomass EmI shielding materials including the pore structure adjustment,preparation process,and micro-control would be *** preparation methods and characteristics of wood,bamboo,cellulose and lignin in EmI shielding field are critically discussed in this paper,and similar biomass EmI materials are summarized and *** composite methods and fillers of various biomass materials were *** paper also highlights the mechanism of EmI shielding as well as existing prospects and challenges for development trends in this field.

关键词： Biomass materials electromagnetic interference shielding micro-nano structure interface control Conductivity

Complement-dependent neuroinflammation in spinal cord injury:from pathology to therapeutic implications

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Neural Regeneration Research 2025年第5期20卷 1324-1335页

作者： Hassan Saad Bachar el Baba Ali Tfaily Firas Kobeissy Juanmarco Gutierrez Gonzalez Daniel Refai Gerald R.Rodts Christian mustroph David Gim.el.Jonathan Grossberg Daniel L.Barrow matthew F.Gary Ali m.Alawieh Department of Neurosurgery Emory University School of MedicineAtlantaGAUSA Department of Neurology Yale UniversityNew HavenCTUSA Center for Neurotrauma Multiomics&Biomarkers(CNMB)Morehouse School of MedicineAtlantaGAUSA

Spinal cord injury remains a major cause of disability in young adults,and beyond acute decompression and rehabilitation,there are no pharmacological treatments to limit the progression of injury and optimize recovery in this *** the thorough investigation of the complement system in triggering and propagating cerebral neuroinflammation,a similar role for complement in spinal neuroinflammation is a focus of ongoing *** this work,we survey the current literature investigating the role of complement in spinal cord injury including the sources of complement proteins,triggers of complement activation,and role of effector functions in the *** study relevant data demonstrating the different triggers of complement activation after spinal cord injury including direct binding to cellular debris,and or activation via antibody binding to damage-associated molecular *** effector functions of complement have been implicated in spinal cord injury,and we critically evaluate recent studies on the dual role of complement anaphylatoxins in spinal cord injury while emphasizing the lack of pathophysiological understanding of the role of opsonins in spinal cord *** this pathophysiological review,we systematically review the different translational approaches used in preclinical models of spinal cord injury and discuss the challenges for future translation into human *** review emphasizes the need for future studies to dissect the roles of different complement pathways in the pathology of spinal cord injury,to evaluate the phases of involvement of opsonins and anaphylatoxins,and to study the role of complement in white matter degeneration and regeneration using translational strategies to supplement genetic models.

关键词： complement neuroinflammation neuroplasticity regeneration spinal cord injury targeted therapy

Effect of substitution group on dielectric properties of 4H-pyrano [3,2-c] quinoline derivatives thin films

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Chinese Physics B 2016年第7期25卷 440-449页

作者： H m Zeyada F m.el.Taweel m m.el.Nahass m m.el.Shabaan Department of Physics Faculty of Science Damietta University Department of Chemistry Faculty of Science Damietta University Department of Physics Faculty of Education Ain Shams University

The AC electrical conductivity and dielectrical properties of 2-amino-6-ethyl-5-oxo-4-（3-phenoxyphenyl）-5,6-dihydro-4H-pyrano[3, 2-c]quinoline-3-carbonitrile（Ph-HPQ） and 2-amino-4-（2-chlorophenyl）-6-ethyl-5-oxo-5,6-dihydro-4H-pyrano [3, 2-c] quinoline-3-carbonitrile（Ch-HPQ） thin films were determined in the frequency range of 0.5 k Hz–5 mHz and the temperature range of 290–443 K. The AC electrical conduction of both compounds in thin film form is governed by the correlated barrier hopping（CBH） mechanism. Some parameters such as the barrier height, the maximum barrier height, the density of charges, and the hopping distance were determined as functions of temperature and frequency. The phenoxyphenyl group has a greater influence on those parameters than the chlorophenyl group. The AC activation energies were determined at different frequencies and temperatures. The dielectric behaviors of Ph-HPQ and Ch-HPQ were investigated using the impedance spectroscopy technique. The impedance data are presented in Nyquist diagrams for different temperatures. The Ch-HPQ films have higher impedance than the Ph-HPQ films. The real dielectric constant and dielectric loss show a remarkable dependence on the frequency and temperature. The Ph-HPQ has higher dielectric constants than the Ch-HPQ.

关键词： thin films quinoline derivatives dielectrical properties correlated barrier hopping

Alternating current characterization of nano-Pt(Ⅱ)octaethylporphyrin(PtOEP) thin film as a new organic semiconductor

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Chinese Physics B 2016年第6期25卷 426-432页

作者： m Dongol m m.el.Nahass A el-Denglawey A A Abuelwafa T Soga Nano and Thin Film Laboratory Physics DepartmentFaculty of ScienceSouth Valley University Physics Department Faculty of EducationAin Shams University Physics Department Faculty of Applied Medical ScienceTaif University Department of Frontier materials Nagoya Institute of Technology

Alternating current（AC） conductivity and dielectric properties of thermally evaporated Au/Pt OEP/Au thin films are investigated each as a function of temperature（303 K–473 K） and frequency（50 Hz–5 mHz）.The frequency dependence of AC conductivity follows the Jonscher universal dynamic *** AC-activation energies are determined at different *** is found that the correlated barrier hopping（CBH） model is the dominant conduction *** variation of the frequency exponent s with temperature is analyzed in terms of the CBH *** barrier height Wm,hopping distance Rω,and the density of localized states N（EF） are valued at different *** constant ε1（ω,T） and dielectric loss ε2（ω,T） are discussed in terms of the dielectric polarization *** dielectric modulus shows the non-Debye relaxation in the *** extracted relaxation time by using the imaginary part of modulus（m’’）is found to follow the Arrhenius law.

关键词： PtOEP thin films AC conductivity dielectric constants organic semiconductors solar cell nano materials

Plasma ignition threshold disparity between silver nanoparticle-based target and bulk silver target at different laser wavelengths

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Plasma Science and Technology 2019年第1期21卷 63-71页

作者： A m.el.SHERBINI m m HAGRASS m R m RIZK E A el-BADAWY Laboratory of Laser and New materials Faculty of Science Cairo University Faculty of Engineering Electrical Engineering Department Alexandria University

Plasma ignition threshold of nanoparticle-based and bulk silver targets was measured in air. The plasma was initiated by a Nd:YAG laser at wavelengths of 355, 532, and 1064 nm. The plasma ignition was monitored utilizing the prominent Ag I line at 546.5 nm. Lower ignition thresholds of the nanoparticle-based silver target were estimated at 0.4?±?0.02, 0.34?±?0.04, and 0.27?±?0.035 J cm^(-2) coupled with the different laser wavelengths, respectively. In contrast, the bulk silver target plasma exhibited an order of magnitude higher ignition threshold. A three orders of magnitude enhanced emission intensity from the nano-based target over the bulk target was achieved at lower levels of laser irradiation. A reduction of the thermal diffusion length of the nanosilver was assumed in order to theoretically predict this reduction in the plasma threshold. In addition, the effect of self-reversal on the resonance lines was taken into consideration.

关键词： NelIBS enhancement nanosilver laser plasma threshold

Effect of Conductive Fillers on the Cyclic Stress-Strain and Nano-Scale Free Volume Properties of Silicone Rubber

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Chinese Journal of Polymer Science 2014年第5期32卷 558-567页

作者： m.H.Abd-el Salam S.el-Gamal m.mohsen D.m.Abd el-maqsoud Physics Department Faculty of Education Ain Shams University Physics Department Faculty of Science Ain Shams University

The effect of carbon black （CB） and graphite （G） powders on the macroscopic and nano-scale free volume properties of silicone rubber based on poly（di-methylsiloxane）（PDmS） was studied through thermal and cyclic mechanical measurements, as well as with positron annihilation lifetime spectroscopy （PALS）. The melting temperature of the composites （Tm） and the endothermic enthalpy of melting （ΔHm） were estimated by differential scanning calorimetry （DSC）. Tm and the degree of crystallinity （χc） of PDmS composites were found to decrease with increasing the CB content. This can be explained due to the increase in physical cross-linking which results in a decrease in the crystallite thickness. Besides, χc was found to be dependent on the filler type. Cyclic stress-strain behavior of PDmS loaded with different contents of filler has been studied. mullins ratio （Rm） was found to be dependent on the filler type and content. It was found that, Rm increases with increasing the filler content due to the increase in physical cross-linking which results in a decrease in the size of free volume, as observed through a decrease of the o-Ps lifetime τ3 measured by PALS. moreover, the hysteresis in PDmS-CB composites was more pronounced than in PDmS-G composites. Furthermore, a correlation was established between the free volume Vf and the mechanical properties of PDmS composites containing different fillers. A negative correlation was observed between Vf and Rm.

关键词： Positron annihilation Positronium Free volume Si-rubber Composite Cyclic mechanical properties.

Physical and Dielectric Properties of Some Nonionic Surfactants

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Journal of materials Science & Technology 1998年第4期14卷 361-367页

作者： el-Anwar, I.m. el-Henawii, S.A. National Research Center Dokki Cairo Egypt Faculty of Science Helwan University Egypt

Fatty acid esters have been prepared by reacting the acid C//1//8 with polyethylene glycols having varying numbers of oxyethylene units (4-88 units) by the direct esterification reaction method. Surface and interfacial tensions were studied at various experimental conditions, including, concentration, temperature and chemical constitution of the surfactant. Critical micelle concentrations (CmC), surface excess and residual area occupied by each surface active agent molecule A have been calculated by using Gibb's equations. CmC values range from 10 to 55 multiplied by 10** minus **5 mole/L for all studied agents, while the residual area occupied by each molecule varies from 0.6 to 1.5 nm**2. Variation of CmC of some of these agents with temperature have been also examined and the obtained data were used to calculate the heat of micellization delta H//m and the entropy change during micellization delta S//m. Values of delta H//m vary from 14.63 kJ/mole to 2.717 kJ/mole depending on the chemical constitution of the agent under consideration. The apparent dipole moments mu of three surfactant were measured following the Headstrand's method. (Edited author abstract) 23 Refs.

关键词： Surface active agents

Calculation of photon shielding properties for some neutron shielding materials

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Nuclear Science and Techniques 2017年第5期28卷 74-80页

作者： A. m. el-Khayatt Physics Department College of Science Al Imam Mohammad Ibn Saud Islamic University (IMSIU) RiyadhSaudi Arabia Reactor Physics Department NRC Atomic Energy Authority 13759 Cairo Egypt

The objective of the present study is to calculate photon shielding parameters for seven polyethylene-based neutron shielding materials. The parameters include the effective atomic number(Z_(eff)), the effective electron density(N_(eff)) for photon interaction and photon energy absorption,and gamma-ray kerma coefficient(kc). The calculations of Z_(eff)are presented as a single-valued and are energy dependent. While Z_(eff)values were calculated via simplistic powerlaw method, the energy-dependent Z_(eff)for photon interaction(Z_(PI-eff)) and photon energy absorption(Z_(PEA-eff)) are obtained via the direct method for energy ranges of 1 keV–100 GeV and 1 keV–20 me V, respectively. The kccoefficients are calculated by summing the contributions of the major partial photon interactions for energy range of 1 keV–100 meV. In most cases, data are presented relative to pure polyethylene to allow direct comparison over a range of energy. The results show that combination of polyethylene with other elements such as lithium and aluminum leads to neutron shielding material with more ability to absorb neutron and crays. Also, the kerma coefficient first increases with Z of the additive element at low photon energies and then converges with pure polyethylene at energies greater than 100 keV.

关键词： Neutron shielding materials Effective atomic number Kerma coefficient c-rays

Feasibility of new ladle-treated Hadfield steel for mining purposes

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International Journal of minerals,metallurgy and materials 2018年第3期25卷 300-309页

作者： m.K. el Fawkhry Central metallurgical Research and Development Institute (CmRDI) Box 87 Helwan Egypt

A debate has arisen over the possibility of using a new ladle-treated Hadfield steel instead of conventional heat-treated Hadfield steel in mining applications. This debate might be solved by identifying the differences between the mechanical properties and strain-hardening properties of conventional heat-treated Hadfield steel and its counterpart ladle-treated Hadfield steel. Tensile and compression tests demonstrated that the ductility of ladle-treated Hadfield steel is similar to that of conventional heat-treated steel. However, the strain-hardening property of the ladle-treated Hadfield steel is almost two times higher than that of the heat-treated Hadfield steel. The results of this study demonstrate that the improvement of the strain-hardening behavior is attributable to the low stacking-fault energy of the main austenite matrix, which results from the high segregation coefficient of carbon and manganese solutes of the main austenite matrix into the new eutectic phase. Superior wear abrasion resistance is a potential consequence of different strain-hardening properties under low and high loads.

关键词： Hadfield steel ladle treatment process wear abrasion resistance strain hardening properties mechanical properties