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Analysis of turbulent mHd Couette nanofluid flow and heat transfer using hybrid dTm-Fdm

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Particuology 2016年第3期14卷 95-101页

作者： S. mosayebidorcheh m. Sheikholeslami m. Hatami d.d. Ganji Young Researchers and Elite Club Najafabad Branch lslamicAzad University Ndjafabad Iran department of mechanical Engineering Lenjan Branch Islamic Azad University lsfahan Iron department of mechanical Engineering Babol University of Technology Babol Iran mechanical Engineering department Engineering and Technical College Esfarayen University Esfarayen North Khorasan lran

Unsteady turbulent magnetohydrodynamic nanofluid hydrothermal treatment is studied. The zero- equation turbulence model is used to simulate turbulent flow. The modeling results obtained by applying the hybrid differential transformation method-finite difference method to solve this problem confirm its viability. An analytical procedure is used for finding the effects of the problem parameters. Results indicate that the average Nusselt number over the lower plate depends linearly on volume fraction of nanofluid, Hall parameter, turbulent Eckert number, and Reynolds number whereas it is inversely proportional on the Hartmann number and the turbulent parameter.

关键词： Turbulent Hall effect Hybrid dTm-Fdm Nanofluid magnetohydrodynarnic couette flow

Hydrogen production by catalytic decomposition of methane using a Fe-based catalyst in a fluidized bed reactor

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Journal of Natural Gas Chemistry 2012年第4期21卷 367-373页

作者： d.Torres S.deLlobet J.L.Pinilla m.J.Lzaro i.Suelves R.moliner instituto de Carboquímica CSICMiguel Luesma Castn 450018 ZaragozaSpain

Catalytic decomposition of methane using a Fe-based catalyst for hydrogen production has been studied in this work. A Fe/Al2O3 catalyst previously developed by our research group has been tested in a fluidized bed reactor （FBR）. A parametric study ot the effects of some process variables, including reaction temperature and space velocity, is undertaken. The operating conditions strongly affect the catalyst performance. methane conversion was increased by increasing the temperature and lowering the space velocity. Using temperatures between 700 and 900℃ and space velocities between 3 and 6 LN/（gcat·h）, a methane conversion in the range of 25%-40% for the gas exiting the reactor could be obtained during a 6 h run. in addition, carbon was deposited in the form of nanofilaments （chain like nanofibers and multiwall nanotubes） with similar properties to those obtained in a fixed bed reactor.

关键词： hydrogen production fluidized bed reactor metal catalysts

Boundary conditions for porous solids saturated with viscous fluid

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Applied mathematics and mechanics(English Edition) 2009年第7期30卷 821-832页

作者： m.d.Sharma department of mathematics Kurukshetra University

Boundary conditions are derived to represent the continuity requirements at the boundaries of a porous solid saturated with viscous fluid. They are derived from the physically grounded principles with a mathematical check on the conservation of energy. The poroelastic solid is a dissipative one for the presence of viscosity in the interstitial fluid. The dissipative stresses due to the viscosity of pore-fluid are well represented in the boundary conditions. The unequal particle motions of two constituents of porous aggre~ gate at a boundary between two solids are explained in terms of the drainage of pore-fluid leading to imperfect bonding. A mathematical model is derived for the partial connec- tion of surface pores at the porous-porous interface. At this interface, the loose-contact slipping and partial pore opening/connection may dissipate a part of strain energy. A numerical example shows that, at the interface between water and oil-saturated sandstone, the modified boundary conditions do affect the energies of the waves refracting into the isotropic porous medium.

关键词： porous solid dissipative boundary conditions

Advanced analytical determination of volatile organic compounds (VOC) and other major contaminants in water samples using GC-ion Trap mS

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Journal of Environmental Sciences 2001年第1期13卷 25-36页

作者： B m Koroma K X Wang d d Jinya Laboratory of Socioeconomic Science of Food Production Nagoya University Japan.

The GC-ion Trap mS is recently one of the most efficient instrumental analysis recommended for understanding the chemistry of volatile organic compounds, not only in water but even in the food chain and other environmental media (air and soil). Results of the experiment conducted on water samples from Kuguri and Yatsutani sampling stations showed considerably higher levels of organic enrichment (COd = 10 mg/L and 11 mg/L respectively). Total concentrations of Pb (0.072 mg/L and 0.093 mg/L) and Cd (0.004 mg/L and 0.011 mg/L) on the other hand, invariably exceeded the maximum allowable concentrations for human health and the living environment (Pb = 0.005 mg/L; Cd = 0.001 mg/L respectively). And the toxicity levels for these contaminants at LC50 showed critical impact on rainbow trout (hypersensitive species) at 0.14 mg/L for Pb and 0.007 mg/L for Cd in 96 hours respectively. Although these major contaminants including phenol and 3-, 4-cresol, showed relatively higher toxicity impact in the experimental media, it would remain contentious to justify any associated potential dangers without regular routine water monitoring, at least for a period of one year. Nevertheless, the data could serve as a benchmark through which other phenomena can easily be investigated.

关键词： www Advanced analytical determination of volatile organic compounds and other major contaminants in water samples using GC-ion Trap mS VOC EB GC

Recovery of some valuable elements from lamprophyre dykes in the Abu Rusheid area, Southeastern desert, Egypt

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Chinese Journal Of Geochemistry 2012年第1期31卷 64-73页

作者： Zaki d.i. Shawky N. El-Sheikh E.m. ahm.d F.Y. ibrahim m.E. Nuclear materials Authority El MaadiP.O.Box 530 CairoEgypt Chemistry dept. Faculty of Science for GirlAl-Azhar UniversityEgypt

in the Abu Rusheid area, Southeastern desert of Egypt, polymineralized (HREEs, U, Zn and Pb) lam-prophyre dykes are recently recorded. The lamprophyre dykes cut cataclastic rocks along share zones in NNW-SSE trends. The secondary U-minerals are essentially represented by uranophane, kasolite, torbernite and autunite. Ex-perimental work was carried out on the lamprophyre dykes for the recovery of uranium and other valuable elements (e.g. Zn, Pb and Al) from 50 kg of technological sample. The optimum conditions were: 100 g/L sulfuric acid con-centration, 1:5 S/L (solid/liquid) and soaking for 15 days at room temperature. The leaching efficiencies for the re-covery of uranium and other elements like Al, Zn and Pb were 40, 33.6, 98.8 and 78, respectively.

关键词：有价元素煌斑岩岩脉沙漠埃及价值最佳工艺条件实验工作

Phytochemical characterisation, in vitro antioxidant and antidiabetic activity of Rosa arvensis Huds. extracts

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Food Bioscience 2022年第6期50卷 1634-1644页

作者： Lazar d.Žarković Ksenija S.mileski Jelena S.matejić Uroš m.Gašić Nemanja F.Rajčević Petar d.marin Ana m.džamić University of Belgrade Studentski trg 1611000BelgradeSerbia University of Niš Department of PharmacyBulevar dr Zorana Đinđića 8118000NišSerbia University of Belgrade Institute for Biological Research “Siniša Stanković”National Institute of Republic of SerbiaBulevar Despota Stefana 14211000BelgradeSerbia

in this study, the chemical composition, antioxidant, and hypoglycemic activity of Rosa arvensis Huds. leaves and fruits collected from Zlatibor, Željin, Veliki Krš mountains and Petnica village (Serbia) were analysed. Phenolic and vitamin profiles, as well as in vitro antioxidant potential and enzyme inhibitory activity on α-amylase and α-glucosidase, were studied. Phytochemical analysis showed higher phenolic content in leaf extracts than in those obtained from fruits. Gallic, chlorogenic and syringic acids were the most abundant phenolic acids, while catechin was the major flavonoid compound. Furthermore, the highest level of α-tocopherol (1.94 mg/100 g fw) in achenes and ascorbic acid (9.60 mg/100 g fw) in hypanthium were quantified in the fruits sampled on the Veliki Krš mt. High antioxidant capacity was observed for the leaf extracts. it was highly correlated with their chemical composition and primarily referred to the catechin content (r > 0.95, p ile the quinic acid had the opposite effect (r > −0.97, p d good α-glucosidase and moderate α-amylase inhibitory potential in contrast to hypanthium and achenes extracts with lower antidiabetic activity. The high phenolic content and noted antioxidative potential were strongly correlated with the α-glucosidase inhibitory activity (r > 0.80, p ile the α-amylase inhibition was only moderately correlated with those compounds (r > 0.49, p mong the tested R. arvensis samples, those from Zlatibor mt. contained the highest amount of target compounds and expressed the highest biological activity. The obtained results suggest that R. arvensis extracts present a new source of bioactive compounds that could be implemented as novel food ingredients.

关键词： Wild roses Phenolics Vitamins HPLC Antioxidant activity Enzyme inhibition

Electrodeless plasma thrusters for spacecraft: a review

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Plasma Science and Technology 2017年第8期19卷 1-24页

作者： S N BATHGATE m m m BiLEK d R mCKENZiE Applied and Plasma Physics School of PhysicsUniversity of Sydney

The physics of electrodeless electric thrusters that use directed plasma to propel spacecraft without employing electrodes subject to plasma erosion is reviewed. Electrodeless plasma thrusters are potentially more durable than presently deployed thrusters that use electrodes such as gridded ion,Hall thrusters, arcjets and resistojets. Like other plasma thrusters, electrodeless thrusters have the advantage of reduced fuel mass compared to chemical thrusters that produce the same thrust. The status of electrodeless plasma thrusters that could be used in communications satellites and in spacecraft for interplanetary missions is examined. Electrodeless thrusters under development or planned for deployment include devices that use a rotating magnetic field; devices that use a rotating electric field; pulsed inductive devices that exploit the Lorentz force on an induced current loop in a plasma; devices that use radiofrequency fields to heat plasmas and have magnetic nozzles to accelerate the hot plasma and other devices that exploit the Lorentz force. Using metrics of specific impulse and thrust efficiency, we find that the most promising designs are those that use Lorentz forces directly to expel plasma and those that use magnetic nozzles to accelerate plasma.

关键词： spacecraft a review propellant Lorentz thrust rotating radiofrequency erosion presently exploit

Effect of Ta_(2)O_(5)nanoparticles on bioactivity,composition,structure,in vitro and in vivo behavior of PEO coatings on mg-alloy

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Journal of magnesium and Alloys 2024年第6期12卷 2360-2379页

作者： d.V.mashtalyar i.m.imshinetskiy V.V.Kashepa K.V.Nadaraia m.A.Piatkova A.i.Pleshkova K.A.Fomenko A.Yu.Ustinov S.L.Sinebryukhov S.V.Gnedenkov institute of Chemistry Far Eastern BranchRussian Academy of SciencesVladivostok690022Russia Far Eastern Federal University Vladivostok690950Russia Regional Clinical dermatovenerological dispensary Vladivostok690033Russia

The present study investigates the physical and chemical characteristics,behavior in vitro and in vivo,and biocompatibility of coatings containing Ta_(2)O_(5),which are obtained by plasma electrolytic oxidation(PEO)on mA8 magnesium *** obtained coatings demonstrate in vivo biocompatibility and in vitro *** to the base PEO coating,the layers containing Ta_(2)O_(5)facilitate the development of apatite in simulated body fluid,suggesting that the inclusion of nanoparticles improves bioactivity of the *** was found that incorporation of Ta_(2)O_(5)nanoparticles increases roughness and porosity of the formed layers by increasing particle concentration in electrolytes for the PEO process contributing to sufficient soft tissue ingrowth in *** on in vivo studies,these coatings also provide favorable tissue response and minimal inflammatory reaction in comparison with the bare magnesium alloy due to protection of living tissues from deleterious corrosion events of magnesium implant such as local alkalization and intense hydrogen *** results obtained in the present study concluded biocompatibility,tissue integration of the PEO coatings containing Ta_(2)O_(5)nanoparticles making them a promising protective layer for biodegradable magnesium implants.

关键词： Plasma electrolytic oxidation Bioactive coatings Tantalum pentoxide Simulated body fluid(SBF) Apatite formation Histology

Computer modelling of metal dissolution in the Presence of Aqueous Electrolyte

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Chinese Physics Letters 2002年第3期19卷 389-390页

作者： R.i.Eglitis m.R.Philpott UniversitatOsnabruck FachbereichPhysikD-49069OsnabruckGermany departmentofmaterialsScience NationalUniversityofSingapore10KentRidgeCrescentSingapore119260

The semi-empirical Hartree-Fock intermediate neglect of differential overlap (iNdO) method was used to explore the potential energy surface of adsorbed water molecules and to speculate, using fairly simple cluster models, on the reaction path followed by metal ions leaving the surface. As an example, iNdO calculations were used to calculate the potential energy curve for a metal atom leaving the surface and entering into a solvation cage composed of tetrahedral arranged water molecules. The effect of adding a NaCl ion pair to the system with the halide ion above the dissolving atom was also explored.

关键词： metals