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Effect of biopolymers on permeability of sand-bentonite mixtures

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Journal of Rock mechanics and Geotechnical Engineering 2020年第5期12卷 1093-1102页

作者： m.S.Biju D.N.Arnepalli Department of Civil Engineering Indian Institute of Technology MadrasChennai600036India

Application of biopolymer-modified geomaterials in waste disposal practices is gaining wide acceptance due to their superior tensile characteristics and improved crack *** is an important design parameter which determines the suitability of a material as a liner for construction of engineered *** this,the permeability characteristics of sand-bentonite mixtures amended with biopolymers was studied using a modified-falling head permeability apparatus under an accelerated gravity *** distilled water and synthetic leachate were utilized as permeant liquid to assess the role of biopolymer amendment on the permeation behavior of sand-bentonite *** results indicate that addition of biopolymers causes aggregation of the clay platelets,which in turn enhances the permeation behavior of the biopolymer-modified sand-bentonite *** mixtures meet the regulatory requirement of the liner.

关键词： Geotechnical centrifuge Landfill liner Synthetic leachate Xanthan gum Guar gum

Seismic fragility of structures isolated by single concave sliding devices for different soil conditions

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Earthquake Engineering and Engineering Vibration 2018年第4期17卷 869-891页

作者： P.Castaldo G.Amendola m.Ripani Department of Structural Geotechnical and Building Engineering (DISEG) Politecnico di Torino Turin Italy Department of Civil Engineering University of Salerno Via Giovanni Paolo H (SA) ltaly Universidad de Buenos Aires. Consejo Nacional de lnvestigaciones Cientificas y Tecnicas ( CONICET). Instituto de Tecnologias y Cieneias de la Ingenieria "Hilario Fernandez Long" (INTECIN). Faeultad de Ingenieria Buenos Aires Argentina

This study deals with the seismic fragility of elastic structural systems equipped with single concave sliding（friction pendulum system（FPS）） isolators considering different soil conditions. The behavior of these systems is analyzed by employing a two-degree-of-freedom model, whereas the FPS response is described by means of a velocity-dependent model. The uncertainty in the seismic inputs is taken into account by considering artificial seismic excitations modelled as timemodulated filtered Gaussian white noise random processes of different intensity within the power spectral density method. In particular, the filter parameters, which control the frequency content of the random excitations, are calibrated to describe stiff, medium and soft soil conditions. The sliding friction coefficient at large velocity is also considered as a random variable modelled through a uniform probability density function. Incremental dynamic analyses are developed in order to evaluate the probabilities of exceeding different limit states related to both the reinforced concrete（RC） superstructure and isolation level, defining the seismic fragility curves within an extensive parametric study carried out for different structural system properties and soil conditions. The abovementioned seismic fragility curves are useful to evaluate the seismic reliability of base-isolated elastic systems equipped with FPS and located in any site for any soil condition.

关键词： friction pendulum devices seismic isolation soil condition frequency content seismic fragility

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

Biophysical interactions between silver nanoparticle-albumin interface and curcumin

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Journal of Pharmaceutical Analysis 2020年第2期10卷 164-177页

作者： Vinod D.Jaiswal P.m.Dongre Department of Biophysics University of MumbaiVidyanagariSantacruzMumbai400098India

Active targeted drug delivery methods facilitate effective uptake of functionalized nanoparticles through receptor-mediated *** recent years,albumin-nanoparticle interaction has been critically examined so that this functionalized nanoparticle can be efficiently loaded with *** present investigation aims at understanding the adsorption of Bovine Serum Albumin(BSA)on Silver Nano-particle(SNP)surface,preparation of soft conjugates(SC)and hard conjugates(HC)of BSA-functionalized SNP(SNP-BSA),and their interaction with curcumin(CUR).HC contains tightly bound BSA whereas SC involves tightly and loosely bound *** in the hydrodynamic radii of conjugates was observed upon SNP incubation with increased concentration of *** different SNP-BSA conjugate ratios were selected to study their interaction with *** spectroscopy showed a strong association between CUR and SNP:BSA ***,binding varied with a change in the conjugate *** Dichroism(CD)/Fourier Transform Infrared(FTIR)spectroscopy revealed the alterations in the secondary structure of BSA upon CUR binding to the *** potential data indicated stable conjugate *** in SNP:BSA conjugate was found to have a higher half-life as compared to the *** believe that this is the first biophysical characterization report of conjugates that can be effectively extrapolated for targeted drug delivery.

关键词： CUR Bovine serum albumin Silver nanoparticles Soft conjugates Hard conjugates Spectroscopy

An Event Horizon Imager(EHI) mission Concept Utilizing medium Earth Orbit Sub-mm Interferometry

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空间科学学报 2021年第2期41卷 211-233页

作者： KUDRIASHOV V mARTIN-NEIRA m ROELOFS F FALCKE H BRINKERINK C BARYSHEV A HOGERHEIJDE m YOUNG A POURSHAGHAGHI H KLEIN-WOLT m mOSCIBRODZKA m DAVELAAR J BARAT I DUESmANN B VALENTA V PERDIGUES ARmENGOL J m DE WILDE D mARTIN IGLESIAS P ALAGHA N VAN DER VORST m Department of Astrophysics/ImAPP Radboud University NijmegenP.O.Box 90106500 GL Nijmegenthe Netherlands ESTEC/ESA Keplerlaan 12201 A2 Noordurigkthe Netherlands mar Planck Institute for Radio Astrorny Auf dem Higel 69D-53121 Bon(Endenich)Germany University of Groningen Landleven 129747 AD Groningenthe Netherlands Leiden Observatory Leiden UniversityPO Box 95132300 RALeidenthe Netherlands Anton Pannekoek Institute for Astronomy University of AmsterdamScience Park 9041098 XHAmsterdamthe Netherlands Center for Computational Astrophysics Flatiron Institute162 Fifth AvenueNew YorkNY 10010USA

Submillimeter interferometry has the potential to image supermassive black holes on event horizon scales,providing tests of the theory of general relativity and increasing our understanding of black hole accretion *** Event Horizon Telescope(EHT) performs these observations from the ground,and its main imaging targets are Sagittarius A~* in the Galactic Center and the black hole at the center of the m87 ***,the EHT is fundamentally limited in its performance by atmospheric effects and sparse terrestrial(u,v)-coverage(Fourier sampling of the image).The scientific interest in quantitative studies of the horizon size and shape of these black holes has motivated studies into using space interferometry which is free of these *** resolution considerations and interstellar scattering effects push the desired observing frequency to bands above 500 *** paper presents the requirements for meeting these science goals,describes the concept of interferometry from Polar or Equatorial medium Earth Orbits(PECmEO) which we dub the Event Horizon Imager(EHI),and utilizes suitable space technology *** this concept,two or three satellites orbit at slightly different orbital radii,resulting in a dense and uniform spiral-shaped(u,v)-coverage over *** local oscillator signals are shared via an inter-satellite link,and the data streams are correlated on-board before final processing on the ***-satellite metrology and satellite positioning are extensively employed to facilitate the knowledge of the instrument position vector,and its time *** European space heritage usable for both the front ends and the antenna technology of such an instrument is *** and future sensors for the required inter-satellite metrology are *** performance estimates and simulation results are given.

关键词： Instrumentation Space VLBI Radio Telescopes

Observational Hubble parameter data constraints on the interactive model of f(T) gravity with particle creation

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Chinese Physics C 2022年第12期46卷 288-297页

作者： S.Ganjizadeh Alireza Amani m.A.Ramzanpour Department of Physics Ayatollah Amoli BranchIslamic Azad UniversityAmolIran

In this study,we consider an open system from the thermodynamic perspective for an adiabatic FRW universe model in which particle creation occurs within the *** this case,the modified continuity equation is obtained,and then,we make it correspond to the continuity equation of f(T)***,we take f(T)gravity with a viscous fluid in the flat-FRW metric,where T is the torsion *** assume the contents of the universe to be dark matter and dark energy and consider an interaction term between *** interesting point of this study is that we make the modified continuity equation resulting from particle creation equivalent to the matter continuity equation resulting from f(T)*** result of this evaluation establishes a relationship between the number of particles and scale *** what follows,we write the corresponding cosmological parameters in terms of the number of particles and also reconstruct the number of particles in terms of the redshift *** then parameterize the Hubble parameter derived from power-law cosmology with 51 data points from the Hubble observational parameter ***,we plot the corresponding cosmological parameters for dark energy in terms of the redshift to investigate the accelerated expansion of the *** addition,by using the sound speed parameter,we discuss the stability and instability analyses of the present model in different eras of the ***,we plot the density parameter values for dark energy and dark matter in terms of the redshift parameter.

关键词： equation of state parameter f(T)gravity viscous fluid particle creation stability analysis

Fluctuation theorem for entropy production at strong coupling

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Chinese Physics B 2020年第1期29卷 175-180页

作者： Y Y Xu J Liu m Feng Faculty of Science Kunming University of Science and TechnologyKunming 650500China Faculty of mechanical and Electrical Engineering Kunming University of Science and TechnologyKunming 650500China State Key Laboratory of magnetic Resonance and Atomic and molecular Physics Wuhan Institute of Physics and MathematicsChinese Academy of SciencesWuhan 430071China School of Physics and microelectronics Zhengzhou UniversityZhengzhou 450001China

Fluctuation theorems have been applied successfully to any system away from thermal equilibrium,which are helpful for understanding the thermodynamic state *** investigate fluctuation theorems for strong coupling between a system and its reservoir,by path-dependent definition of work and heat satisfying the first law of *** present the fluctuation theorems for two kinds of entropy *** is the informational entropy production,which is always non-negative and can be employed in either strong or weak coupling *** other is the thermodynamic entropy production,which differs from the informational entropy production at strong coupling by the effects regarding the *** find that,it is the negative work on the reservoir,rather than the nonequilibrium of the thermal reservoir,which invalidates the thermodynamic entropy production at strong *** results indicate that the effects from the reservoir are essential to understanding thermodynamic processes at strong coupling.

关键词： fluctuation theorem entropy production strong coupling

Nonlinear beam formulation incorporating surface energy and size effect:application in nano-bridges

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Applied mathematics and mechanics(English Edition) 2016年第5期37卷 583-600页

作者： A.KOOCHI H.HOSSEINI-TOUDESHKY m.ABADYAN Department of Aerospace Engineering Amirkabir University of TechnologyTehran 15875-4413Iran mechanical Engineering Group Shahrekord BranchIslamic Azad UniversityShahrekord ***Iran

A nonlinear beam formulation is presented based on the Gurtin-murdoch surface elasticity and the modified couple stress theory. The developed model theoretically takes into account coupled effects of the energy of surface layer and microstructures size- dependency. The mid-plane stretching of a beam is incorporated using von-Karman nonlinear strains. Hamilton＇s principle is used to determine the nonlinear governing equation of motion and the corresponding boundary conditions. As a case study, pull-in instability of an electromechanical nano-bridge structure is studied using the proposed formulation. The nonlinear governing equation is solved by the analytical reduced order method （ROm） as well as the numerical solution. Effects of various parameters including surface layer, size dependency, dispersion forces, and structural damping on the pull- in parameters of the nano-bridges are discussed. Comparison of the results with the literature reveals capability of the present model in demonstrating the impact of nano- scale phenomena on the pull-in threshold of the nano-bridges.

关键词： surface energy size effect nonlinear beam formulation electromechanicalnano-bridge pull-in instability

Physical-Chemical Characterization of Nanodispersed Powders Produced by a Plasma-Chemical Technique

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Plasma Science and Technology 2007年第3期9卷 273-279页

作者： m.GEORGIEVA G.VISSOKOV Iv.GRANCHAROV Department of Technology of Inorganic Substances University of Chemical Technology and Metallurgy8St.Kliment Ohridski Blvd.1756 SofiaBulgaria

This article presents a review on the physical-chemical properties and characteristics of plasma-chemically produced nanodispersed powders （NDP）, such as metals, oxides, nitrides, carbides, and catalysts. The plasma-chemical preparatior~ of the powders was carried out in thermal plasma （TP） created by means of high-current electric arcs, plasma jets, high-frequency （HF） discharges, etc. We also discuss certain properties and characteristics of the NDPs, which are determined largely by the conditions of preparation.

关键词： plasma-chemical treatment nitrides thermodynamic analysis