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Influence of indoor airflow on airborne disease transmission in a classroom

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Building Simulation 2024年第3期17卷 355-370页

作者： mojtaba Zabihi ri li Joshua Brinkerhoff School of Engineering Faculty of Applied ScienceUniversity of British ColumbiaKelownaCanada

It has been widely accepted that the most effective way to mitigate airborne disease transmission in an indoor space is to increase the ventilation airflow,measured in air change per hour(ACH).However,increasing ACH did not effectively prevent the spread of *** better understand the role of ACH and airflow large-scale patterns,a comprehensive fully transient computational fluid dynamics(CFD)simulation of two-phase flows based on a discrete phase model(DPm)was performed in a university classroom setting with people *** investigations encompass various particle sizes,ventilation layouts,and flow *** findings demonstrated that the particle size threshold at which particles are deemed airborne is highly influenced by the background flow strength and large-scale flow pattern,ranging from 5µm to 10µm in the cases *** effects of occupants are significant and must be precisely accounted for in respiratory particle transport *** enhanced ventilation design(UFAD-CDR)for university classrooms is introduced that places a premium on mitigating airborne disease *** to the baseline design at the same ACH,this design successfully reduced the maximum number density of respiratory particles by up to 85%.A novel airflow-related parameter,Horizontality,is introduced to quantify and connect the large-scale airflow pattern with indoor aerosol *** underscores that ACH alone cannot ensure or regulate air *** addition to the necessary ACH for air exchange,minimizing horizontal bulk motion is essential for reducing aerosol transmissibility within the room.

关键词： aerosol transmission airflow pattern horizontality COVID-19 simulation classroom ventilation

On calculating glacial isostatic adjustment

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Geodesy and Geodynamics 2024年第5期15卷 441-452页

作者： l.m.Cathles Cornell University IthacaNY 14853USA

modeling the earth's fluid and elastic response to the melting of the glaciers of the last ice age is the most direct way to infer the earth's radial viscosity ***,we compare two methods for calculating the viscoelastic response to surface *** one,the elastic equation of motion is converted to a viscoelastic equation using the Correspondence *** the other,elastic deformation is added to the viscous flow as isostatic adjustment *** two modeling methods predict adjustment histories that are different enough to potentially impact the interpretation of the observed glacial isostatic adjustment(GIA).The differences arise from buoyancy and whether fluid displacements are subjected to hydrostatic *** methods agree if they use the same equations and boundary *** origin of the differences is determined by varying the boundary conditions and pre-stress application.

关键词： Glacial isostatic adjustment Viscoelastic normal modes Hydrostatic pre-stress Elastic buoyancy Correspondence principle

Carbon monoxide as C1 Building Block in Fine Chemical Synthesis

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Chinese Journal of Chemistry 2024年第2期42卷 199-221页

作者： Rui m.B.Carrilho m.rio J.F.Calvete Gabor mikle laszlo Kollar m.riette m.Pereira University of Coimbra Coimbra Chemistry CentreDepartment of ChemistryRua Larga3004-535 CoimbraPortugal Department of General and Inorganic Chemistry and ElKH-PTE Research Groupfor Selective Chemical Syntheses University of PecsIfjusag utja 6H-7624 PecsHungary

Carbon monoxide(CO)has become one of the most relevant and versatile renewable C1 building blocks for chemical synthesis,especially in the fine chemicals industry,due to the development of efficient and selective catalysts for its *** this review,we present a comprehensive critical analysis of the last 10 years literature on the use of CO as a renewable feedstock for fine chemicals *** review is organized by type of catalytic reaction,namely alkene and alkyne carbonylation,hydroformylation,carbonylation of aryl halides,carbonylative cross-coupling and C-H *** examples of the synthesis of relevant building blocks and/or known pharmaceuticals are *** is placed on examples of utilizing CO as the C1 building block in one or more catalytic *** catalyst used and the reaction conditions are consistently presented throughout all of the examples.

关键词： Carbon monoxide Fine chemicals Carbonylation Hydroformylation C-H functionalization

Selective and asymmetric ion transport in covalent organic framework-based two-dimensional nanofluidic devices

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International Journal of Smart and Nano materials 2024年第1期15卷 186-197页

作者： li-Qiu Huang Shuang Chen ri-Jian mo Zhong-Qiu li Xing-Hua Xia State Key laboratory of Analytical Chemistry for life Science School of Chemistry and Chemical EngineeringNanjing UniversityNanjingChina

Two-dimensional(2D)covalent organic framework(COF)mem-branes featuring well-aligned and programmable vertical nano-channels have emerged as a promising candidate for advanced nanofluidic devices and showcased vast potential in the fields of smart-gating,ion-separation,and ***,the transverse interlayer nanochannels with a height of sub-nanometer-scale in 2D-COF membranes have scarcely been studied in ***,we report the ion transport characteristics in 2D interlayer nanochannels of protonated CoF *** dis-tinct surface-charge-governed ionic conductance in domination of electrolyte concentration below 1o-3 m as well as the exceptional anion/cation(Cl^(-)/K^(+))selectivity is revealed due to the pronounced charge and nano-confinement ***,evident ion current rectification is witnessed when incorporating asymmetric geometry into the system,which is attributed to the dynamic process of ion enrichment and dissipation within the protonated *** work offers immense prospects for 2D-COF membranes in the fields of biomimetic nanofluidic devices and cutting-edge electronic devices.

关键词： Two-dimensional covalent organic framework interlayernanochannels ion transport characteristics nanofluidic device

Effect of cold-working on corrosion induced damage in lug joints

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Defence Technology（防务技术） 2024年第6期36卷 175-182页

作者： Ramanath m.N Chikmath l. murthy H. Department of Aerospace Engineering Indian Institute of Technology-MadrasChennai 600036India Department of Aeronautical Engineering KLS Gogte Institute of TechnologyBelagavi 590008India

lug joints are preferred joineries for transferring heavy loads to parent components in aerospace *** experience corrosion due to environmental conditions,improper surface finishes and rubbing displacement between the pin and *** causes damage of different sizes and shapes near the *** degradation due to corrosion-induced damage is modelled as a through-pit at one of the identified critical locations through stress *** effect of this pit on fatigue crack initiation life is ***-hole is pre-stressed by cold-working and the benefits of inducing plastic wake on the intended performance of the lug joint during the damages due to corrosion are brought out and compared with non-cold-worked *** analysis is performed on this lug joint with *** results obtained highlight the benefits of cold-working and the methodology can be extended to damage growth and analyse the effect of surface treatments for better structural integrity of components of aerospace vehicles.

关键词： lug joint Corrosion Crack initiation Cold-working Structural integrity

Effect of radiative loss mechanisms on FIR thermometric parameters of Nd^(3+)-doped lithium tellurite glasses

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Journal of Rare Earths 2024年第7期42卷 1250-1257,I0002页

作者： C.Y.morassuti A.P.l Silva l.A.O.Nunes S.m.lima l.H.C.Andrade Optical and Photothermal Spectroscopy Group(GEOF) Center for Studies in Natural Resources(CERNA)State University of Mato Grosso do Sul(UEMS)C.P.351DouradosMSBrazil Renato Archer Information Technology Center Dom Pedro I Highway(SP-65)Km 1436-Chácaras Campos dos AmaraisCampinasSPBrazil Institute of Physics of São Carlos University of São PauloSão CarlosSPBrazil

Nd^(3+)-doped tellurite glasses are promising materials for thermometers based on the fluorescence intensity ratio(FIR)***,at high Nd^(3+)concentrations,energy transfer(ET)processes such as optical reabsorption and cross-relaxation can affect the Nd^(3+)emission,which has been little explored in the ***,the present work investigated the use of Nd^(3+)-doped tellurite glass(samples doped with Nd^(3+)at 0.2 mol%,0.5 mol%,2.0 mol%,and 4.0 mol%)in fluorescence thermometers,in the temperature range from 299 to 371 *** results indicate a strong dependence of the FIR parameters on the Nd^(3+)concentration,due to changes in the emission band profiles caused by optical reabsorption of the Nd^(3+)emissions and cross-relaxation processes.A decrease of the relative sensitivity of the ratio^(4)F_(5/2)→^(4)I_(9/2)/^(4)F_(3/2)→^(4)I_(9/2)is observed for samples doped with higher amounts of Nd^(3+).The maximum relative sensitivity at 299 K is 3.00%/K,which is the highest value among the reported Nd^(3+)ions.

关键词： Nd^(3+)-doped tellurite glass Fluorescence intensity ratio Optical thermometry Judd-Ofelt Rare earths

A comprehensive review on the processing-property relationships of laser strengthened magnesium

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Journal of magnesium and Alloys 2024年第1期12卷 1-34页

作者： Alessandro m.Ralls Aaksheta Agnel Pradeep l.menezes Department of mechanical Engineering University of Nevada RenoRenoNV 89557United States

Among the existing series of softer metals,magnesium(mg)has attracted much attention due to its impressive strength-to-weight ***,due to its ease of deformability,mg tends to suffer from rapid degradation in a wide variety of abrasive and electrochemical *** method of improving its surface properties is through surface modification *** the existing techniques,laser shock peening(lSP)has been one of the most widely utilized processes due to its surface-hardening-like *** this understanding,a comprehensive review has yet to exist that encapsulates the strengthening mechanism of lSP for mg and its influence in degradation *** review aims to encapsulate the existing research around the lSP field for ***,an understanding of the surface-strengthening effects in relation to its mechanical,tribological,corrosion,and tribo-corrosion characteristics is ***,the feasibility of lSP for mg materials in critical industries is also *** this work,a novel understanding of lSP for mg can be understood,which can provide a future direction for research in this field.

关键词： laser shock peening magnesium Surface deformation Tribology microstructure

Corrosion testing of X52 and X80 steels immersed in stimulated emulsions using a real petroleum sample

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Petroleum Research 2024年第2期9卷 304-316页

作者： l.m.Quej-Ake J.l.Alamilla A.Contreras Instituto mexicano del Petróleo Eje Central Lázaro CárdenasNorte 152San Bartolo AtepehuacanGustavo A.MaderoCiudad de MéxicoC.P.07730México

The aim of this study is to evaluate the internal corrosion process on X52 and X80 steels/real petroleum interfaces containing condensed hydrocarbon plus oilfield-produced water,which were subjected to stimulated emulsions using 50/50 vol ratio mixtures at 45℃,different hydrodynamic conditions,1 h,and 24 h.A washing process by using deionized water was proposed to simulate and identify the corrosiveness of the hydrocarbon phase after 24 h of exposure *** characterization by electrochemical impedance spectroscopy and the monitoring of the polarization curves indicated that X80 steel/oilfield-produced water interfaces were more susceptible to corrosion than X52 steel exposed to oilfield-produced *** combined speed rotation of 600 rpm using a magnetic stirrer+600 rpm using a rotating disk electrode decreased the corrosion rate on X52 *** stimulated emulsions made of hydrocarbon+oilfield-produced water and hydrocarbon+deionized water at 24 h increased the corrosion rate on X80 steel(0.34 mm/year and 0.43 mm/year,respectively),promoting the formation of erosion and pitting *** types of corrosion depended mainly on the physicochemical properties of the hydrocarbon,oilfield-produced water,exposure times,and hydrodynamic systems in which the hydrocarbon was studied.

关键词： Corrosion Emulsions X52 steel X80 steel

Spark Plasma Sintering of mg-based Alloys:microstructure,mechanical Properties,Corrosion Behavior,and Tribological Performance

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Journal of magnesium and Alloys 2024年第2期12卷 405-442页

作者： Alessandro m.Ralls mohammadreza Daroonparvar Pradeep l.menezes Department of mechanical Engineering University of Nevada RenoRenoNV89557United States

Within the past ten years,spark plasma sintering(SPS)has become an increasingly popular process for mg *** the SPS process,interparticle diffusion of compressed particles is rapidly achieved due to the concept of Joule *** to traditional and additive manufacturing(Am)techniques,SPS gives unique control of the structural and microstructural features of mg *** doing so,their mechanical,tribological,and corrosion properties can be *** great advancements in this field have been made,these pieces of knowledge are scattered and have not been contextualized into a single *** motivation of this work is to address this scientific gap and to provide a groundwork for understanding the basics of SPS manufacturing for *** do so,the existing body of SPS mg literature was first surveyed,with a focus on their structural formation and degradation *** was found that successful mg SPS fabrication highly depended on the processing temperature,particle size,and particle *** addition of metal and ceramic composites also affected their microstructural features due to the Zener pinning *** degradative environments,their performance depends on their structural features and whether they have secondary phased *** industrial applications,SPS'd mg was found to have great potential in biomedical,hydrogen storage,battery,automotive,and recycling *** prospects to advance the field include using mg as a doping agent for crystallite size refinement and using bulk metallic mg-based glass powders for amorphous SPS *** these findings,the interactions of multi-composites on the processing-structure-property relationships of SPS mg is not well *** total,this work will provide a useful direction in the SPS field and serve as a milestone for future mg-based SPS manufacturing.

关键词： Spark plasma sintering magnesium alloys Nanocrystalline Tribology mechanical properties Corrosion