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Enhancing Indoor User Localization:An Adaptive Bayesian Approach for Multi-Floor Environments

Computers, Materials & Continua 2024年第8期80卷 1889-1905页

作者： Abdulraqeb Alhammadi Zaid Ahmed Shamsan Arijit de Center for Artificial Intelligence and Robotics(CAIRO) Malaysia-Japan International Institute of TechnologyUniversiti Teknologi MalaysiaKuala Lumpur54100Malaysia department of Electrical Engineering College of EngineeringImam Mohammad Ibn Saud Islamic University(IMSIU)Riyadh11432Saudi Arabia department of Information Engineering Electronics and TelecommunicationsSapienza UniversityRome00185Italy

Indoor localization systems are crucial in addressing the limitations of traditional global positioning system(gPS)in indoor environments due to signal attenuation *** complex indoor spaces become more sophisticated,indoor localization systems become essential for improving user experience,safety,and operational *** localization methods based on Wi-Fi fingerprints require a high-density location fingerprint database,but this can increase the computational burden in the online *** networks,which integrate prior knowledge or domain expertise,are an effective solution for accurately determining indoor user *** networks use probabilistic reasoning to model relationships among various localization parameters for indoor environments that are challenging to *** article proposes an adaptive Bayesian model for multi-floor environments based on fingerprinting techniques to minimize errors in estimating user *** proposed system is an off-the-shelf solution that uses existing Wi-Fi infrastructures to estimate user’s *** operates in both online and offline *** the offline phase,a mobile device with Wi-Fi capability collects radio signals,while in the online phase,generating samples using gibbs sampling based on the proposed Bayesian model and radio map to predict user’s *** results unequivocally showcase the superior performance of the proposed model when compared to other existing models and *** proposed model achieved an impressive lower average localization error,surpassing the accuracy of competing ***,this noteworthy achievement was attained with minimal reliance on reference points,underscoring the efficiency and efficacy of the proposed model in accurately estimating user locations in indoor environments.

关键词： Localization positioning Bayesian fingerprinting received signal strength(RSS)

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Challenges and opportunities in the production of magnesium parts by directed energy deposition processes

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Journal of Magnesium and Alloys 2024年第5期12卷 1663-1686页

作者： gürel Cam Ali günen Iskenderun Technical University Faculty of Engineering and Natural SciencesDepartment of Mechanical Engineering31200 Iskenderun-HatayTurkey Iskenderun Technical University Faculty of Engineering and Natural SciencesDepartment of Metallurgy and Materials Engineering31200 Iskenderun-HatayTurkey

Mg-alloys have gained considerable attention in recent years for their outstanding properties such as lightweight,high specific strength,and corrosion resistance,making them attractive for applications in medical,aerospace,automotive,and other transport ***,their widespread application is hindered by their low formability at room temperature due to limited slip *** Mg-alloys have low mechanical properties due to the presence of casting.defects such as porosity and anisotropy in addition to the high *** casting methods benefit from established process optimization techniques for these problems,additive manufacturing methods are increasingly replacing casting methods in Mg alloys as they provide more precise control over the microstructure and allow specific grain orientations,potentially enabling easier optimization of anisotropy properties in certain *** metal additive manufacturing(MAM)technology also results in some manufacturing.defects such as inhomogeneous microstructural evolution and porosity and additively manufactured Mg alloy parts exhibit lower properties than the wrought parts,they in general exhibit superior properties than the cast ***,MAM is a promising technique to produce Mg alloy *** energy deposition processes,particularly wire arc directed energy deposition(WA-deD),have emerged as an advantageous additive manufacturing(AM)technique for metallic materials including magnesium alloys,offering advantages such as high deposition rates,improved material efficiency,and reduced production costs compared to subtractive ***,the inherent challenges associated with magnesium,such as its high reactivity and susceptibility to oxidation,pose unique hurdles in the application of this *** review paper delves into the progress made in the application of deD technology to Mg-alloys,its challenges,and ***,the predominant imperfections,notably inhomo

关键词： Additive manufacturing deD processes Arc-deD Wire arc additive manufacturing(WAAM) 3-D printing High deposition rate

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呼吸门控微CT对慢性肺炎小鼠模型的纵向研究

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国际医学放射学杂志 2011年第1期34卷 91-页

作者： X.Artaechevarria D.Blanco D.Pérez-Martín g.de biurrun L.M.Montuenga J.P.de Torres 张晓东 Cancer Imaging Laboratory Oncology DivisionCenter for Applied Medical ResearchUniversity of Navarra

目的评价呼吸门控微CT在探测和监视慢性肺炎小鼠模型中进行量化分析的可行性,并将影像测量与肺功能测试、组织形态观察相比较。方法

关键词： X线微CT 动物疾病模型肺部炎症呼吸门控分段

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Flow characteristics and bubble statistics during the fragmentation process of the ingested main cavity in plunging breaking waves

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Journal of Hydrodynamics 2024年第3期36卷 546-555页

作者： Wen-bin Zhang Wei-wen Zhao de-cheng Wan Computational Marine Hydrodynamics Lab(CMHL) School of Naval ArchitectureOcean and Civil EngineeringShanghai Jiao Tong UniversityShanghai200240China

Plunging breaking waves play an important role in the exchange of heat,momentum,and mass between the atmosphere and *** this paper,a series of direct numerical simulations is conducted to investigate the fragmentation process of the ingested main cavity in plunging breaking *** two-phase Navier-Stokes equations are solved using the finite-volume method based on adaptive refinement *** free surface is captured using a geometrical volume of fluid *** 2-D,3-D simulations are *** flow fields at different stages of wave breaking are presented and quantitative analysis for bubbles is *** 2-D instantaneous vorticity field and local velocity field are visualized to discuss the general flow characteristics during the fragmentation *** a 2-D parametric study is conducted to investigate the differences in the flow characteristics during the fragmentation process under different wave parameters including initial wave steepness(ε),Bond number(Bo),and Reynolds number(Re).3-D vortex structures are shown to further investigate the mechanisms behind the differences in the flow *** bubble size distributions under two different initial wave steepness are also discussed with their relationship to the fragmentation process of the ingested main *** research offers a significant understanding of the distinct procedures and fundamental dynamics involved in wave breaking,enhancing our comprehension of this intricate event.

关键词： Plunging breaking waves multiphase flow bubble statistics

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Effect of thermo-mechanical conditions during constrained friction processing on the particle refinement of AM50 Mg-alloy phases

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Journal of Magnesium and Alloys 2024年第6期12卷 2298-2311页

作者： Camila Caroline de Castro AndréMartins Neves Benjamin Klusemann Helmholtz-Zentrum Hereon Institute of Material and Process DesignSolid-State Materials Processing21502 GeesthachtGermany Helmholtz-Zentrum Hereon Institute of Hydrogen TechnologySystem Design for Mobility21502 GeesthachtGermany Helmut Schmidt University/University of the german Federal Armed Forces Hamburg Department of Mechanical and Civil Engineering22043 HamburgGermany Leuphana University Lüneburg Institute for Production Technology and Systems21335 LüneburgGermany

Constrained Friction Processing(CFP)is a novel solid-state processing technique suitable for lightweight materials,such Mg-and *** technique enables grain size refinement to fine or even ultrafine *** this study,the effect of CFP on the microstructural refinement of AM50 rods is investigated in terms of particle size and morphology of the eutectic and secondary phases originally present in the base material,in particular the eutecticβ-Mg_(17)Al_(12)and Al-Mn *** that purpose,as-cast and solution heat-treated base material and processed samples were *** Al_(8)Mn_(5) intermetallic phase was identified as the main secondary phase present in all samples before and after the processing.A notorious refinement of these particles was observed,starting from particles with an average equivalent length of a few micrometers to around 560 nm after the *** refinement of the secondary phase refinement is attributed to a mechanism analogous to the attrition comminution,where the combination of temperature increase and shearing of the material enables the continuous breaking of the brittle intermetallic particles into smaller *** for the eutectic phase,the results indicate the presence of the partially divorcedβ-Mg_(17)Al_(12)particles exclusively in the as-cast base material,indicating that no further phase transformations regarding the eutectic phase,such as dynamic precipitation,occurred after the *** the case of the processed as-cast material analyzed after the CFP,the thermal energy generated during the processing led to temperature values above the solvus limit of the eutectic phase,which associated with the mechanical breakage of the particles,enabled the complete dissolution of this ***,CFP was successfully demonstrated to promote an extensive microstructure refinement in multiple aspects,in terms of grain sizes of theα-Mg phase and presence and morphology of the Al-Mn and eutecticβ-Mg_(17)Al_(12).

关键词： Constrained friction processing AM50 Refill friction stir spot welding Extrusion β-Mg_(17)Al_(12) Al-Mn phases

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Numerical analysis of coupled sloshing and motion of a cylindrical FPSO in regular waves

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Journal of Hydrodynamics 2024年第3期36卷 457-465页

作者： Wei-wen Zhao Xiao-long Yang.de-cheng Wan Computational Marine Hydrodynamics Lab(CMHL) School of Naval ArchitectureOcean and Civil EngineeringShanghai Jiao Tong UniversityShanghai200240China Offshore Oil Engineering Co.Ltd. Tianjin300461China

In this paper,the coupled sloshing and motion characteristics of a cylindrical floating production storage offloading(CFPSO)are numerically investigated by means of computational fluid dynamics(CFD)*** simulations are performed using an in-house CFD solver naoe-FOAM-SJTU which is developed based on *** active wave generating-absorbing boundary condition(gABC)is utilized for wave generation and *** stabilized k-omega SST turbulence model are used to avoid excessive eddy viscosity near the free *** with and without partially filled liquid tanks in regular waves with different wave periods are simulated and vertical planar motions such as surge,heave and pitch response amplitude operators(RAOs)are *** due to liquid sloshing and wave loads are extracted and *** free surface motions inside liquid tanks in one wave period presented to explain the motion characteristics.

关键词： Coupled analysis liquid sloshing wave motion cylindrical floating production storage offloading(CFPSO)

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Correcting distortions of thin-walled machined parts by machine hammer peening

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Chinese Journal of Aeronautics 2024年第6期37卷 439-453页

作者： Aitor MADARIAgA Mikel CUESTA gorka ORTIZ-de-ZARATE Eneko SAENZ-de-ARgANDONA denis SORIANO Michael B.PRIME Pedro Jose ARRAZOLA department of Materials University of ManchesterOxford RoadManchester M139PLUnited Kingdom Mechanical and Industrial Production department Faculty of EngineeringMondragon UnibertsitateaArrasate 20500Spain Los Alamos National Laboratory Los AlamosNew MexicoUSA

Thin-walled aerostructural components frequently get distorted after the machining *** to correct distortions or eventually rejecting parts significantly increases the *** paper proposes a new approach to correct distortions in thin-walled components by strategically applying hammer peening on target surfaces of a machined *** alloy 7475-T7351 was chosen for this *** study was divided in two ***,the residual stresses(RS)induced by four different pneumatic hammer peening conditions(modifying the stepover distance and initial offset)were characterised in a test coupon,and one of the conditions was selected for the next *** the second stage,a FEM model was used to predict distortions caused by machining in a representative ***,the RS induced by hammer peening were included in an FEM model to define two hammer peening strategies(varying the coverage area)to analyse the capability to reduce *** workpieces were machined and then treated with the simulated hammer peening strategies for experimental *** in the test coupon showed that pneumatic hammer peening can generate high compressive RS(-50 to350 MPa)up to 800 lm depth,with their magnitude increasing with a reduced stepover *** of hammer peening over 4% of the surface of the representative workpiece reduced the machininginduced distortions by 37%,and a coverage area of 100% led to and overcorrection by a factor of *** confirms that hammer peening can be strategically applied(in target areas and changing the percentage of coverage)to correct low or severe distortions.

关键词： Aeronautics Machining,Hammer Peening Aluminium alloy Distortions Residual Stress

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A remote sensing approach to estimate the load bearing capacity of soil

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Information Processing in Agriculture 2024年第1期11卷 109-116页

作者： Italo Rômulo Mendes de Souza Edson Eyji Sano Renato Paiva de Lima Anderson Rodrigo da Silva Statistics and geoprocessing Laboratory Instituto Federal GoianoGeraldo Silva Nascimento RoadKm 2.575790-000 UrutaíGoiásBrazil Embrapa Cerrados BR-020 RoadKm 18Mailbox 0822373310-970 PlanaltinaDFBrazil department of Soil Science ‘Luiz de Queiroz’College of AgricultureUniversity of São PauloAv.Pádua Dias235-AgronomiaPiracicabaSP 13418-900Brazil

Preconsolidation pressure(σp)of soil can be considered as an indicator of the Load Bearing Capacity(LBC),which is the tolerated surface pressure before compaction,often caused by the traffic of agricultural *** this pioneering study,a remote sensing approach was introduced to estimate LBC throughσp from soils of the“Rio Preto”Hydrographic Basin,Bahia State,Brazil,in a monthly time lapse from 2016 to ***,σp is measured by a laborious and time demanding laboratory analysis,making it unfeasible to map large *** innovative methodology of this work consists of combining active–passive satellite data on soil moisture and pedotransfer functions of clay content and water matric potential to obtain geo-located estimates ofσ*** were analysed under different classes of soil use,land cover and slope;95%confidence intervals were built for the time series of mean values of LBC for each *** overall seasonal variation in LBC estimates is similar in areas with annual crops,grasslands and natural vegetation,and flat areas are less affected by soil moisture variations over the year(between seasons).LBC decreased,in general,at about 0.5%a year in flat ***,these areas demand attention,since they occupy 86%of the Basin and are mostly subjected to agricultural soil management and surface pressure by heavy machinery.

关键词： Soil compaction SMAP Preconsolidation stress Brazilian Cerrado

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Solid-liquid extraction for yttrium recovery using porous polymeric resin(XAD-7) functionalized with D_(2)EHPA

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Journal of Rare Earths 2024年第9期42卷 1764-1773,I0005页

作者： P.A.Martínez-Montoya R.g.Sanchez-Alvarado D.Y.Medina-Velazquez M.L.Carrera-Jota P.garnica-Chávez A.de J.Morales-Ramirez Higher School of Chemical Engineering and Extractive Industries ESIQIEIPNDepartment of Metallurgical EngineeringUPALM S/NCol.LindavistaGustavo A.Madero Cd.de MéxicoC.P07738Mexico Metropolitan Autonomous University Department of MaterialsBasic Sciences and EngineeringAv.San Pablo No.180Col.Reynosa TamaulipasCd.de MéxicoC.P02200Mexico Center for Research and Technological Innovation CIITECIPNCda.de CECATIs/nSanta CatarinaAzcapotzalcoC.P02250CDMXMexico

The recovery of yttrium is proposed by applying a solid-liquid extraction process using di-2-ethyl hexylphosphoric acid(D2EHPA) as extracting *** extracting agents were supported on a macro porous polymeric resin XAD-7(solid phase).Yttrium ions extraction and discharge tests were performed,firstly from a synthetic aqueous solution of 100 mg/L Y(liquid phase) at 25℃ with *** effects of pH of aqueous solutions bearing yttrium,volume fraction of extracting agents and the solid/liquid(S/L)ratio on the yttrium recovery were *** most favorable conditions for yttrium ions extraction are;20 vol% D_(2)EHPA functionalized resin,pH=1.5 and an S/L ratio of 10 mg/mL The discharge of yttrium ions was done under the same conditions of extraction stage,using a 2 mol/L [H_(2)SO_(4)] as stripping *** to 80% yttrium is extracted,while 75% yttrium is recovered in the striping *** all experiments,the reaction equilibrium is reached after 20 min,and the kinetics for the extraction stage was determined as a second-order ***,experiments were carried out to discharge the yttriumloaded resins,and it has been determined that the best pH value to strip the Y ions is *** tests of extraction and discharge for yttrium ions show that the functionalized resin can work at least five cycles without decreasing its ***,the proposed process was tested in a real solution with Y ions fro m a waste fluorescent la mp powder leached in H_(2)SO_(4),demonstrating the ability to effectively recover yttrium,separating it from various metals from the studied residue.

关键词： Yttrium recovery Rare earth solid-liquid extraction XAD-7 resin Fluorescent lamps recycling Solid-liquid kinetics extraction

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Structure and 2p decay mechanism of^(18)Mg

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Nuclear Science and Techniques 2024年第6期35卷 145-154页

作者： Long Zhou de-Qing Fang Si-Min Wang Hui Hua Key Laboratory of Nuclear Physics and Ion-beam Application(MOE) Institute of Modern PhysicsFudan UniversityShanghai 200433China Shanghai Research Center for Theoretical Nuclear Physics NSFC and Fudan UniversityShanghai 200438China School of Physics and State Key Laboratory of Nuclear Physics and Technology Peking UniversityBeijing 100871China

The recently discovered,extremely proton-rich nuclide 18 Mg exhibits ground-state decay via two sequential two-proton(2p)emissions through the intermediate nucleus,*** study investigates the structure and the initial 2p decay mechanism of^(18)Mgby examining the density and correlations of the valence protons using a three-body gamow coupled-channel *** results show that the ground state of^(18)Mgis significantly influenced by the continuum,resulting in a significant s-wave ***,based on the current framework,this does not lead to a significant deviation in mirror symmetry in either the structure or spectroscopy of the 18Mg-18C ***,the time evolution analysis of the^(18)Mgground state suggests a simultaneous 2p emission during the first step of *** observed nucleon-nucleon correlations align with those of the light-mass 2p emitters,indicating a consistent decay behavior within this nuclear region.

关键词： Structure of^(18)Mg Two-proton decay Proton-proton correlation

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