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Boosting the catalytic activity toward oxygen reduction via a heterostructure of porous iron oxide-decorated 2D NiO/NG nanosheets

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Journal of Energy Chemistry 2024年第6期93卷 669-681,I0016页

作者： Kakali Maiti Matthew t.Curnan Hyung Jun Kim Kyeounghak Kim Jeong Woo Han Department of Chemical Engineering Pohang University of Science and Technology(POSTECH)PohangGyeongbuk 37673Republic of Korea Department of Materials Science and Engineering Research Institute of Advanced MaterialsSeoul National UniversitySeoul 08826Republic of Korea Department of Chemical Engineering Clean-Energy Research InstituteHanyang UniversitySeoul 04763Republic of Korea CSIR-Institute of Minerals and Materials technology RRL CampusAcharya ViharBhubaneswarOdisha 751013India

As a noble metal substitute,two-dimensional(2D)hierarchical nano-frame structures have attracted great interest as candidate catalysts due to their remarkable advantages-high intrinsic activity,high electron mobility,and straightforward surface ***,they may replace Pt-based catalysts in oxygen reduction reaction(ORR)***,a simple method is developed to design hierarchical nano-frame structures assembled via 2D NiO and N-doped graphene(NG)*** procedure can yield nanostructures that satisfy the criteria correlated with improved electrocatalytic performance,such as large surface area,numerous undercoordinated atoms,and high defect ***,porous NG nanosheet architectures,featuring NiO nanosheets densely coordinated with accessible holey Fe_(2)O_(3) moieties,can enhance mesoporosity and balance *** improvements can facilitate charge transport and expose formerly inaccessible reaction sites,maximizing active site density *** functional theory(DFt)calculations reveal favored O_(2) adsorption and dissociation on Fe_(2)O_(3) hybrid structures when supported by 2D NiO and NG nanomaterials,given 2D materials donated charge to Fe_(2)O_(3) active *** systematic studies reveal that synergistic contributions are responsible for enriching the catalytic activity of Fe_(2)O_(3)@NiO/NG in alkaline media-encompassing internal voids and pores,unique hierarchical support structures,and concentrated N-dopant and bimetallic atomic ***,this work expands the toolbox for designing and synthesizing highly efficient 2D/2D shelled functional nanomaterials with transition metals,endeavoring to benefit energy conversion and related ORR applications.

关键词： N-doped graphene Holey Fe_(2)O_(3)nanocrystals NiO nanosheets High catalytic performance ORR

Aerodynamics of a tandem-Bladed Axial Compressor Rotor under Circumferential Distortion at Different Rotational Speeds

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Journal of thermal Science 2024年第4期33卷 1340-1356页

作者： Amit KUMAR Jerry t.JOHN A.M.PRADEEP R.A.DAKKERMANS Dragan KOZULOVIC Department of Aerospace Engineering Indian Institute of Technology BombayMumbai400076India Department of Automotive and Aeronautical Engineering Hamburg University of Applied Sciences20099HamburgGermany Institute of Jet Propulsion Bundeswehr University Munich85577NeubibergGermany

For most aircraft engines,inflow distortion is *** distortion is known to degrade the aerodynamic performance and stable operating limits of a *** rotor configuration is an arrangement that effectively controls the growth of the boundary layer over the suction surface of the ***,a higher total pressure rise can be achieved through this unconventional design approach involving the splitting of the blade into forward and aft *** is expected that the effect of inlet flow distortion would be more severe for a tandem-rotor design due to the greater flow turning inherent in such ***,this aspect needs to be thoroughly *** present study discusses the effect of circumferential distortion on the tandem-rotor at different rotational ***-annulus RANS simulations using ANSYS CFX are used in the present *** performance of the rotor at a particular flow coefficient and different rotational speeds is *** total pressure and efficiency are observed to drop at lower mass flow rates under the influence of circumferential *** loss region in each blade passage is mainly associated with the blade wake,tip leakage vortex,secondary flow,and boundary ***,their contribution varies from passage to passage,particularly in the distorted *** the lower span,the wake width is found to be higher than that at a higher *** to the redistribution of the mass flow,the circumferential extent reduces at a higher *** the undistorted sector,the strength of the tip leakage vortex is significantly higher at the design rotational speed than at lower *** distortion near the tip region promotes an early vortex breakdown even at the design operating *** adversely affects the total pressure,efficiency,and stall *** clean flow conditions,this phenomenon is only observed near the stall *** the design operating condition,the breakdown of the forward rotor tip l

关键词： tandem rotor circumferential distortion loss tip leakage vortex vortex breakdown diffusion factor aerodynamics of compressor blade

technological advancements in millet dehulling and polishing process: An insight into pretreatment methods, machineries and impact on nutritional quality

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Grain & Oil Science and technology 2024年第3期7卷 186-195页

作者： Shagolshem Mukta Singh Jayasree Joshi t P.Srinivasa Rao Agricultural and Food Engineering Department Indian Institute of Technology KharagpurKharagpurWest Bengal 721302India

Millets are widely recognized for their nutritional significance;however, the methods employed for their processing are currently lacking. this article primarily focuses on the advanced technologies and progressions in millet dehulling and polishing. these technologies operate based on the fundamental principles of compression-shearing, abrasion-friction, and centrifugal-impact forces. Processing of millets can be challenging because of the physical characteristics and tight attachment of hull and bran to the endosperm. However, several dehullers have been designed to solve this problem for different kinds of millets. In addition, the nutritional and anti-nutritional characteristics undergo alterations due to both dehulling and polishing processes. these alterations are thoroughly examined and discussed in this article. Specifically, anti-nutrients such as tannins and phytate are predominantly found in the outer pericarp of the grain and experience a reduction after undergoing dehulling and polishing. the nutritional properties are also subjected to a reduction;however, this reduction can be mitigated by subjecting the grains to certain pretreatments before dehulling and polishing. these treatments serve to enhance dehulling efficiency and nutrient digestibility while simultaneously reducing the presence of anti-nutrients. Novel thermal and non-thermal methodologies such as microwave, hydrothermal, high-pressure processing, and ohmic heating can be employed for processing millets, thereby diminishing the loss of nutrients. Additional research can be carried out to investigate their impact on the dehulling and polishing of millets.

关键词： Millets Dehulling Polishing Pretreatment Novel thermal and non-thermal techniques

A particle-resolved heat-particle-fluid coupling model by DEM-IMB-LBM

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Journal of Rock Mechanics and Geotechnical Engineering 2024年第6期16卷 2267-2281页

作者： Ming Xia Jinlong Fu Y.t.Feng Fengqiang Gong Jin Yu Hunan Key Laboratory of Geomechanics and Engineering Safety Xiangtan UniversityXiangtan411105China Zienkiewicz Institute for Modelling Data and AISwansea UniversitySwanseaSA18EPUK School of Civil Engineering Southeast UniversityNanjing211189China Fujian Research Center for tunneling and Urban Underground Space Engineering Huaqiao UniversityXiamen361021China

Multifield coupling is frequently encountered and also an active area of research in geotechnical *** this work,a particle-resolved direct numerical simulation(PR-DNS)technique is extended to simulate particle-fluid interaction problems involving heat transfer at the grain *** this extended technique,an immersed moving boundary(IMB)scheme is used to couple the discrete element method(DEM)and lattice Boltzmann method(LBM),while a recently proposed Dirichlet-type thermal boundary condition is also adapted to account for heat transfer between fluid phase and solid *** resulting DEM-IBM-LBM model is robust to simulate moving curved boundaries with constant temperature in thermal *** facilitate the understanding and implementation of this coupled model for non-isothermal problems,a complete list is given for the conversion of relevant physical variables to lattice ***,benchmark tests,including a single-particle sedimentation and a two-particle drafting-kissing-tumbling(DKt)simulation with heat transfer,are carried out to validate the accuracy of our coupled *** further investigate the role of heat transfer in particle-laden flows,two multiple-particle problems with heat transfer are *** examples demonstrate that the proposed coupling model is a promising high-resolution approach for simulating the heat-particle-fluid coupling at the grain level.

关键词： Particle-fluid interaction Heat transfer Discrete element method(DEM) Lattice Boltzmann method(LBM) Dirichlet-type thermal boundary Direct numerical simulation

Reply to the note by Li Piani et al.

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Defence technology（防务技术） 2024年第1期31卷 603-606页

作者： t.Li Piani J.Weerheijm L.J.Sluys tU Delft Stevinweg 12628 CNDelftthe Netherlands tNO PO Box 452280 AARijswijkthe Netherlands NLDA Faculty of Military Sciences1781 CADen Helderthe Netherlands

In 2017,a ballistic phenomenological model was proposed by the authors of Ref.[1] to numerically simulate the experimental depths of small caliber projectiles impacting walls made of *** opportunity for a new model in the field revealed from the observation that two older models recently used by the authors of Ref.[2] shared a linear relationship between the penetration depth P and the impacting velocity v_(O).

关键词： Penetration Adobe Modeling

Food security amid the COVID-19 pandemic in Central Asia:Evidence from rural tajikistan

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Journal of Integrative Agriculture 2024年第8期23卷 2853-2867页

作者： Yuhan Zhao Chen Qian Yumei Zhang Xiande Li Kamiljon t.Akramov Institute of Agricultural Economics and Development Chinese Academy of Agricultural SciencesBeijing 100081China Academy of Global Food Economics and Policy College of Economics and ManagementChina Agricultural UniversityBeijing 100083China International Food Policy Research Institute(IFPRI) WashingtonD.C.20005USA

Food security has been long understudied in the context of Central *** present an analysis examining household-level food demand for tajikistan and assessing the magnitude of its food security changes during the COVID-19 *** on an extensive household survey data set from tajikistan,we estimate the expenditure,income,and price elasticities for nine food categories using the QUAIDS ***,we develop a microsimulation model using the estimated elasticities to assess the dual impact of declining remittance income and rising food prices stemming from the pandemic *** are significant differences in demand elasticities across food groups,with high elasticities observed for nutritious foods,such as meat,fruit,eggs,and milk,in rural ***,our findings show that changes in remittance income and food prices significantly negatively affected food security for rural households during the COVID-19 *** findings have important implications for policymakers concerned about rural livelihoods and food security in remittance-receiving economies during the post-pandemic period.

关键词： international remittances food security COVID-19 tajikistan Central Asia

Photoluminescence and ratiometric thermo-response of Eu^(2+)and Eu^(3+)in BaAl_(2)B_(2)O_(7):Eu^(2+),Eu^(3+)phosphor materials

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Journal of Rare Earths 2024年第7期42卷 1240-1249,I0002页

作者： Ziyao Wang Haitao Fu Xiufeng Zhan Bo tong Guofeng Ma H.t.(Bert)Hintzen Institute of Innovative Science and technology Shenyang UniversityShenyang110044China College of Mechanical Engineering Shenyang UniversityShenyang110044China Faculty of Applied Sciences Delft University of Technology2629 JBDelftthe Netherlands

A novel Eu^(2+)-Eu^(3+)co-activated ratiometric thermo-sensitive phosphor was developed and synthesized by solid-state *** valence state of Eu,photoluminescence and thermo-sensitive performance of the phosphor prepared either in ambient air or carbothermally were investigated and *** phosphor shows high sensitivity(Sa=0.0173 K^(-1),S_(r)=0.461%/K)and superior signal discriminability(Δν∼10380 cm^(−1)).the thermo-sensitive performance is subject to the dual effects of different thermo-responses by Eu^(2+)versus Eu^(3+)combined with energy transfer from Eu^(2+)to Eu^(3+),so that the sensitivity of the phosphor in the temperature range presents a non-monotonic *** development of the BaAl_(2)B_(2)O_(7):Eu^(2+),Eu^(3+)phosphor is not only expected to be relevant for application in the field of temperature sensing,but also of reference significance for improving the sensitivity by means of energy transfer between co-activator ions over a wider temperature range of Eu^(2+)-Eu^(3+)co-activated ratiometric thermo-sensitive phosphors.

关键词： Photoluminescence Ratiometric thermo-response Phosphor Eu^(2+)/Eu^(3+) Rare earths

Supposition of graphene stacks to estimate the contact resistance and conductivity of nanocomposites

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Applied Mathematics and Mechanics(English Edition) 2024年第4期45卷 663-676页

作者： Y.ZARE M.t.MUNIR G.J.WENG K.Y.RHEE Biomaterials and tissue Engineering Research Group Department of Interdisciplinary TechnologiesBreast Cancer Research CenterMotamed Cancer InstituteTehran ***Iran College of Engineering and technology American University of the Middle EastEgaila 54200Kuwait Department of Mechanical and Aerospace Engineering Rutgers UniversityNew BrunswickNJ 08903U.S.A. Department of Mechanical Engineering(BK21 Four) College of EngineeringKyung Hee UniversityYongin 446701Republic of Korea

In this study,the effects of stacked nanosheets and the surrounding interphase zone on the resistance of the contact region between nanosheets and the tunneling conductivity of samples are evaluated with developed equations superior to those previously *** contact resistance and nanocomposite conductivity are modeled by several influencing factors,including stack properties,interphase depth,tunneling size,and contact *** developed model's accuracy is verified through numerous experimental *** further validate the models and establish correlations between parameters,the effects of all the variables on contact resistance and nanocomposite conductivity are ***,the contact resistance is primarily dependent on the polymer tunnel resistivity,contact area,and tunneling *** dimensions of the graphene nanosheets significantly influence the conductivity,which ranges from 0 S/m to90 S/*** increased number of nanosheets in stacks and a larger gap between them enhance the nanocomposite's ***,the thicker interphase and smaller tunneling size can lead to higher sample conductivity due to their optimistic effects on the percolation threshold and network efficacy.

关键词： graphene polymer composite stacked nanosheet tunneling conductivity contact resistance interphase

Design,simulation,and testing of a tunable MEMS multi-threshold inertial switch

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Microsystems & Nanoengineering 2024年第2期10卷 37-46页

作者： Qiu Xu Rodrigo t.Rocha Yousef Algoos Eric Feron Mohammad I.Younis Faculty of Electronic Information Engineering Huaiyin Institute of TechnologyHuai’an223003PR China Computer Electrical and Mathematical Science and Engineering DivisionKing Abdullah University of Science and TechnologyThuwal23955-6900Saudi Arabia Piezoelectric Microsystem technologies Silicon Austria LabsVillach9524Austria Physical Sciences and Engineering Division King Abdullah University of Science and TechnologyThuwal23955Saudi Arabia Mechanical Engineering Department State University of New YorkBinghamtonNY13902USA

this paper presents a tunable multi-threshold micro-electromechanical inertial switch with adjustable threshold *** demonstrated device combines the advantages of accelerometers in providing quantitative acceleration measurements and g-threshold switches in saving power when in the inactive state upon experiencing acceleration below the *** designed proof-of-concept device with two thresholds consists of a cantilever microbeam and two stationary electrodes placed at different positions in the sensing *** adjustable threshold capability and the effect of the shock duration on the threshold acceleration are analytically investigated using a nonlinear beam *** are shown for the relationships among the applied bias voltage,the duration of shock impact,and the tunable *** fabricated prototypes are tested using a shock-table *** analytical results agree with the experimental *** designed device concept is very promising for the classification of the shock and impact loads in transportation and healthcare applications.

关键词： tunable acceleration testing