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Deep bed filtration model for cake filtration and erosion

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Applied Mathematics and Mechanics(English Edition) 2024年第2期45卷 355-372页

作者： l.i.KUZMiNA Y.V.OSiPOV A.R.PEStEREV Department of Applied Mathematics HSE UniversityMoscow 101000Russia Department of Computer Science and Applied Mathematics Moscow State University of Civil EngineeringMoscow 129337Russia

Many phenomena in nature and technology are associated with the filtration of suspensions and colloids in porous media. two main types of particle deposition,namely, cake filtration at the inl.t and deep bed filtration throughout the entire porous medium, are studied by different models. A unified approach for the transport and deposition of particles based on the deep bed filtration model is proposed. A variable suspension flow rate, proportional.to the number of free pores at the inl.t of the porous medium, is considered. to model cake filtration, this flow rate is introduced into the mass balance equation of deep bed filtration. For the cake filtration without deposit erosion,the suspension flow rate decreases to zero, and the suspension does not penetrate deep into the porous medium. in the case of the cake filtration with erosion, the suspension flow rate is nonzero, and the deposit is distributed throughout the entire porous medium. An exact sol.tion is obtained for a constant filtration function. the method of characteristics is used to construct the asymptotics of the concentration front of suspended and retained particles for a filtration function in a general form. Explicit formulae are obtained for a linear filtration function. the properties of these sol.tions are studied in detail.

关键词： deep bed filtration cake filtration porous medium particle deposition and erosion anal.tical sol.tion concentration front

Phase composition,conductivity,and sensor properties of cerium-doped indium oxide

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Nano Materials Science 2024年第2期6卷 193-200页

作者： M.i.ikim G.N.Gerasimov V.F.Gromov O.J.ilegbusi l.i.trakhtenberg N.N.Semenov Federal Research Center for Chemical Physics of RAS MoscowRussia University of Central Florida OrlandoFLUSA Moscow institute of Physics and technology(State University) DolgoprudnyMoscow RegionRussia lomonosov Moscow State University MoscowRussia

the hydrothermal synthesis of in_(2)O_(3)and CeO_(2)–in_(2)O_(3)is investigated as well as the properties of sensor layers based on these *** the synthesis of in_(2)O_(3),intermediate products in(OH)_(3)and inOOH are formed,which are the precursors of stable cubic(c-in_(2)O_(3))and metastable rhombohedral(rh-in_(2)O_(3))phases,respectively.A transition from c-in_(2)O_(3)to rh-in_(2)O_(3)is observed with the addition of CeO_(2).the introduction of cerium into rh-in_(2)O_(3)results in a decrease in the sensor response to hydrogen,while it increases in composites based on c-in_(2)O_(3).the data on the sensor activity of the composites correl.te with XPS results in which CeO_(2)causes a decrease in the concentrations of chemisorbed oxygen and oxygen vacancies in rh-in_(2)O_(3).the reverse situation is observed in composites based on c-in_(2)O_(3).Compared to in_(2)O_(3)and CeO_(2)–in_(2)O_(3)obtained by other methods,the synthesized composites demonstrate maximum response to H_(2)at low temperatures by 70–100℃,and have short response time(0.2–0.5 s),short recovery time(6–7 s),and long-term stabil.ty.A model is proposed for the dependence of sensitivity on the direction of electron transfer between in_(2)O_(3)and CeO_(2).

关键词： Cerium oxide indium oxide Nanocomposite Hydrothermal method Cubic phase Rhombohedral phase Sensor response Conductivity Hydrogen Response/recovery time

Porphyrins,phthalocyanines,and rel.ted covalent-organic frameworks in the photochemical and electrochemical water spl.tting:A review

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Particuology 2024年第7期90卷 236-265页

作者： Oxana V.Kharissova Yolanda Peña Méndez Boris i.Kharisov Aleksandr lNikolaev Edith luévano-Hipól.to lucy t.González Universidad Autónoma de Nuevo león Ave.Universidad s/nSan Nicolás de los GarzaNuevo León66455Mexico Department of Chemistry Moscow State UniversityVorobievy HillsMoscowRussia CONACYt-Universidad Autónoma de Nuevo león Facultad de Ingeniería Civil-Departamento de Ecomateriales y EnergíaCd.UniversitariaC.P.66455San Nicolás de los GarzaNLMexico tecnologico de Monterrey Escuela de Ingeniería y CienciasMonterreyNuevo León 64890Mexico tecnologico de Monterrey Centro del AguaMonterreyNuevo León 64890Mexico

in this review,the possibil.ties of photochemical and electrochemical water spl.tting(WS)using porphyrins,phthalocyanines,rel.ted macrocycles,and their metal complexes are *** efforts are being carried out in order to develop novel and cheap methods for water decomposition to generate inexhaustible greener energy sources(molecular hydrogen)instead of oil and *** processes of WS in heterogeneous and homogeneous media require novel photo-and electrocatalysts,in particular those on macrocycle basis.A high WS efficiency has been observed for porphyrins and phthalocyanines,showing their suitabil.ty both for HER and OER processes are available using these rel.tive compounds for WS *** can be used in photocatal.tic and electrocatal.tic WS processes both in their free forms or as metal porphyrins/porphyrinates,mainly loaded on various inorganic materials,such as Au NPs,C_(3)N_(4),GaP,KtaO_(3),GaP,and so on,as part of porphyrin-containing polymers or on electrode surface as modifying coatings,being sometimes better than commercial catalysts,such as Pt/*** H2 evol.tion can be considerably depended on the shape of porphyrin particles;in particular,porphyrin nanowires can yield up to 20 times more H2 than its *** certain cases,both HER and OER can be driven in the same electrol.te using metal *** capacity of metal porphyrins to generate ROS(in particular,singl.t oxygen 1O_(2))under ultrasonic treatment is known and can be successfully used for H_(2)O_(2) and O_(2) *** can be used in similar processes in free form or as composites with inorganic or organic counterparts,being immobilized on nanocarbons,metal oxides and salts,or simply dissolved in water acting in a homogeneous *** additional use of ultrasound can lead to better results due to the synergistic effect of the sonochemical.treatment and ***-organic frameworks are also applied for WS purposes and are mainly based

关键词： Porphyrins Phthalocyanines COFs Water spl.tting Photocatalysis Electrocatalysis

Combustion characteristics of low-qual.ty lignite for different bed material sphericities in a circul.ting fluidized bed boiler:A numerical study

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Particuology 2024年第7期90卷 364-382页

作者： Barış Gürel Gülşah Karaca Dolgun Osman ipek Ali Keçebaş Department of Mechanical Engineering Engineering FacultySüleyman Demirel UniversityÇünürIspartaTurkey Department of Energy Systems Engineering Technology FacultyMuğla SıtkıKoçman UniversityKötekliMenteşeMuğlaTurkey

this study delves into the combustion behavior of various lignite types within a circul.ting fluidized bed boiler(CFBB),with a primary focus on the impact of different bed material sphericity ratios(0.5,0.7,and 0.9).Utilizing bed material with a sphericity ratio of 0.9 sourced from theÇan power plant and verified through experimentation,the research reveals several key ***,furnace temperatures tended to rise with higher sphericity ratios,albeit with variations between lignite types,particularly highlighting the complexity of this rel.tionship in the case of Gli-tunçbilek *** levels in the combustion chamber remained consistent across different sphericity ratios,indicating minimal influence on pressure *** combustion efficiency,especially at the bottom of the boiler,was observed at lower sphericity levels(0.5 and 0.7)forÇan lignite,as reflected in CO_(2) mole *** NO_(x) emissions generally decreased with lower sphericity,the sensitivity to sphericity varied by lignite type,with ilgın lignite showcasing low NO_(x) but high SO_(2) emissions,underscoring the intricate interplay between lignite properties,sphericity,and ***,this study advances our understanding of CFBB combustion dynamics,offering insights valuable for optimizing performance and emissions control,particularly in lignite-based power.

关键词： Circul.ting fluidized bed boiler Computational particle fluid dynamics method Particle sphericity ratios NO_(x)and SO_(2)emissions Energy production efficiency

Simplified seismic scenario analysis of existing masonry buildings accounting for local site effects

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Frontiers of Structural and Civil Engineering 2024年第2期18卷 309-318页

作者： Ayşe E.ÖZSOYÖZBAY işıl SANRi KARAPiNAR Zehra N.KUtlU ismail E.KiliÇ Department of Civil Engineering Maltepe UniversityIstanbul 34857Turkey School of Engineering and Construction Oryx Universal CollegeDoha 12253Qatar

this study discusses the effects of local sites and hazard amplification on the seismic vulnerabil.ty assessment of existing masonry *** this context,a rapid seismic evaluation procedure was implemented on an old masonry building stock in the historical center Gal.ta,located inistanbul.to determine the seismic risk priority of the built *** scenarios were generated for all soil classes,different moment magnitudes,and source-to-site distances to obtain more accurate results for the seismic vulnerabil.ty assessment of the studied building ***,damage distributions estimated under nine different scenarios with/without site effects were compared and illustrated in maps to discuss changes in vulnerabil.ty owing to amplification *** this study,by re-examining the rapid seismic evaluation procedure by including geo-hazard-based assessment,the importance of site effects on the vulnerabil.ty and risk assessment of built heritage was *** proposed framework integrating field data and local site effects is believed to advance the current applications for vulnerabil.ty assessment of masonry buildings and provide an improvement in the application of rapid seismic assessment procedures with more reliable results.

关键词： masonry buildings seismic vulnerabil.ty assessment cultural heritage local site effect

investigation of the effects of radial clearance on the screw conveyor performances for different inclinations

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Particuology 2024年第9期92卷 72-80页

作者： Berna Bol.t Birgül Aşçıoğlu temiztaş Enes Sezer Department of Mechanical Engineering Yıldız Technical University34349BeşiktaşİstanbulTurkey

Screw conveyors are widely used for bulk material *** study investigates the critical role of radial clearance,the gap between the screw and the conveyor body,on performance across various inclination *** Discrete Element Method(DEM)is employed to analyze the effects of different radial clearances on conveyor performance for concrete aggregate and sand as bulk *** efficiencies and capacity losses serve as key performance indicators,quantitatively assessed for each radial clearance and inclination *** validation is conducted to corroborate the *** the study,the optimal radial clearance was identified as 1.5 to 3 times of the particle *** optimal clearance minimizes the material jamming and increases the performance for screw conveyors with different inclinations and bulk material.types as a result.

关键词： Screw conveyors Radial clearance Discrete element method(DEM) Volumetric efficiency Conveyor performance

Exact sol.tions for magnetohydrodynamic nanofluids flow and heat transfer over a permeable axisymmetric radially stretching/shrinking sheet

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Chinese Physics B 2024年第2期33卷 108-114页

作者： U.S.Mahabaleshwar G.P.Vanitha l.M.Pérez Emad H.Aly i.Pop Department of Studies in Mathematics Davangere UniversityShivagangothriDavangereIndia Departamento de F´ısica FACIUniversidad de Tarapac´aCasilla 7DAricaChile Department of Mathematics Faculty of EducationAin Shams UniversityRoxyCairoEgypt Department of Mathematics Babes-Bolyai University400084 Cluj-NapocaRomania

We report on the magnetohydrodynamic impact on the axisymmetric flow of Al_(2)O_(3)/Cu nanoparticles suspended in H_(2)O past a stretched/shrinked *** the use of partial differential equations and the corresponding thermophysical characteristics of nanoparticles,the physical flow process is *** resultant nonlinear system of partial differential equations is converted into a system of ordinary differential equations using the suitable similarity *** transformed differential equations are solved *** of the magnetic parameter,solid volume fraction and stretching/shrinking parameter on momentum and temperature distribution have been analyzed and interpreted *** skin friction and Nusselt number were also *** addition,existence of dual sol.tion was deduced for the shrinking sheet and unique sol.tion for the stretching ***,Al_(2)O_(3)/H_(2)O nanofluid flow has better thermal conductivity on comparing with Cu/H_(2)O ***,it was found that the first sol.tions of the stream are stable and physically realizable,whereas those of the second ones are unstable.

关键词： magnetohydrodynamic nanofluid stretching/shrinking sheet axisymmetric flow anal.tical sol.tion suction/injection

Highly Defective Dark tiO_(2) Modified with Pt: Effects of Precursor Nature and Preparation Method on Photocatal.tic Properties

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transactions of tianjin University 2024年第2期30卷 198-209页

作者： E.D.Fakhrutdinova O.A.Reutova t.A.Bugrova i.Yu.Ovsyuk l.S.Kibis O.A.Stonkus D.B.Vasilchenko O.V.Vodyankina V.A.Svetlychnyi National Research tomsk State University TomskRussia 634050 Novosibirsk State University NovosibirskRussia 630090 Boreskov institute of Catalysis NovosibirskRussia 630090 Nikolaev institute of inorganic Chemistry NovosibirskRussia 630090

the study focused on the modification with pl.tinum of dark defective titania obtained via pulsed laser abl.tion. Both the method of Pt introduction and the nature of the Pt precursor were varied. All samples exhibited similar phase compositions, specific surface areas, and Pt contents. High-resol.tion transmission electron microscopy coupled with pulsed CO adsorption revealed increased dispersity when photoreduction and the hydroxonitrate complex (Me _(4) N) _(2) [Pt _(2) (OH) _(2) (NO _(3) ) _(8) ] were used. the sample featured a high content of single-atom species and subnano-sized Pt clusters. the X-ray photoelectron spectroscopy results showed that the photoreduction method facil.tated the appearance of a larger number of Pt ^(2+) states, which appeared owing to the strong metal-support interaction (SMSi) eff ect of the transfer of electron density from the electron-saturated defects on the tiO _(2) surface to Pt ^(4+) . in the hydrogen evol.tion reaction, samples with a significant fraction of the Pt ^(2+) ionic component, capable of generating short-lived Pt^(0) single-atom sites under irradiation due to the SMSi eff ect, exhibited the highest photocatal.tic activity. the 0.5Pt(C)/tiO_(2) -Ph sample exhibited the highest hydrogen yield with a quantum efficiency of 0.53, retaining its activity even after 8 h of operation.

关键词： Dark(black)tiO_(2) Pulsed laser abl.tion Pl.tinum reduction method Precursor type Photocatalysis Hydrogen evol.tion reaction

All-optical image denoising using a diffractive visual processor

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light(Science & Applications) 2024年第3期13卷 429-445页

作者： Çağatay işıl.tianyi Gan Fazil Onuralp Ardic Koray Mentesoglu Jagrit Digani Huseyin Karaca Hanlong Chen Jingxi li Deniz Mengu Mona Jarrahi Kaan Akşit Aydogan Ozcan Electrical and Computer Engineering Department University of CaliforniaLos AngelesCA 90095USA Bioengineering Department University of CaliforniaLos AngelesCA 90095USA California NanoSystems institute(CNSi) University of CaliforniaLos AngelesCA 90095USA University College london Department of Computer ScienceLondonUnited Kingdom

image denoising,one of the essential inverse problems,targets to remove noise/artifacts from input *** general,digital image denoising algorithms,executed on computers,present l.tency due to several iterations implemented in,e.g.,graphics processing units(GPUs).While deep learning-enabled methods can operate non-iteratively,they also introduce l.tency and impose a significant computational burden,leading to increased power ***,we introduce an analog diffractive image denoiser to all-optically and non-iteratively clean various forms of noise and artifacts from input images–implemented at the speed of light propagation within a thin diffractive visual processor that axially spansis the wavelength of *** all-optical image denoiser comprises passive transmissive layers optimized using deep learning to physically scatter the optical modes that represent various noise features,causing them to miss the output image Field-of-View(FoV)while retaining the object features of *** results show that these diffractive denoisers can efficiently remove salt and pepper noise and image rendering-rel.ted spatial artifacts from input phase or intensity images while achieving an output power efficiency of~30–40%.We experimentally demonstrated the effectiveness of this analog denoiser architecture using a 3D-printed diffractive visual processor operating at the terahertz *** to their speed,power-efficiency,and minimal computational overhead,all-optical diffractive denoisers can be transformative for various image display and projection systems,including,e.g.,holographic displays.

关键词： remove rendering holographic