检索结果-南通市图书馆

Mathematical modelling of ball and plate system with experimental and correlation function-based model validation

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

Control Theory and Technology 2024年第2期22卷 326-341页

作者： T.r.Dil Kumar s.j.Mija Department of Electrical Engineering National Institute of Technology CalicutKozhikode673601KeralaIndia

The ball and plate system is an inherently nonlinear under actuated benchmark system used for validating the performance of various control schemes. A mathematical model depicting the dynamics close to that of the system is very much required for such a test bed. In this correspondence, the complete nonlinear model, a simplified nonlinear model, and a linearized model of the ball and plate system are developed. The system comprises a ball and plate mechanism and a rotary servo unit. The ball and plate mechanism is modelled using the Euler–Lagrange method, whereas the rotary servo subsystem is modelled from the first principles. The nonlinear model of the combined system is developed by including the dynamics of the servo motor with gear and rolling resistance between the ball and the plate. The simplified nonlinear model of the system is obtained with suitable assumptions. The model is linearized around the operating point using the jacobian. The validity of the developed models is investigated through correlation function analysis. The open-loop response of the three models, viz., nonlinear, simplified nonlinear, and linearized models, is analyzed in the MATLAB/simulink platform. since the open-loop system is unstable, the experimental validation of the model is performed with a double-loop PsO (particle swarm optimization) PID control scheme.

关键词： Ball and plate system Correlation function Model validation Particle swarm optimization(PsO) PsO PID controller

single-atom Pt on carbon nanotubes for selective electrocatalysis

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Carbon Energy 2024年第1期6卷 63-71页

作者： samuel s.Hardisty Xiaoqian Lin Anthony r.j.Kucernak David Zitoun Department of Chemistry Bar Ilan Institute of Nanotechnology and Advanced Materials(BINA)Bar Ilan UniversityRamat GanIsrael Department of Chemistry Molecular Science Research HubImperial College LondonLondonUK

Utilizing supported single atoms as catalysts presents an opportunity to reduce the usage of critical raw materials such as platinum,which are essential for electrochemical reactions such as hydrogen oxidation reaction(HOr).Herein,we describe the synthesis of a Pt single electrocatalyst inside single-walled carbon nanotubes(sWCNTs)via a redox *** via electron microscopy,X-ray photoelectron microscopy,and X-ray absorption spectroscopy show the single-atom nature of the *** electrochemical behavior of the sample to hydrogen and oxygen was investigated using the advanced floating electrode technique,which minimizes mass transport limitations and gives a thorough insight into the activity of the *** single-atom samples showed higher HOr activity than state-of-the-art 30%Pt/C while almost no oxygen reduction reaction activity in the proton exchange membrane fuel cell operating *** selective activity toward HOr arose as the main fingerprint of the catalyst confinement in the sWCNTs.

关键词： confinement electrocatalysis hydrogen platinum single atom catalysts

Inflow and outflow permeability tests in a very soft clay under low stresses

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

journal of rock Mechanics and Geotechnical Engineering 2024年第8期16卷 3270-3283页

作者： j.W.s.Vargas F.A.B.Danziger F.r.Lopes T.Lunne Federal University of rio de janeiro Rio de JaneiroBrazil Norwegian Geotechnical Institute OsloNorway

In situ inflow and outflow permeability tests with the BAT probe at sarapuíII soft clay test site are presented.A description of the BAT permeability test is provided,discussing its advantages and shortcomings,especially in the case of very soft clays under low *** pressures were monitored during probe installation and were found to be slightly lower than piezocone u2 pore pressures,consistent with the position of the *** role of filter tip saturation was investigated after the usual saturation procedure provided an unsatisfactory pore pressure response during probe *** show that the vacuum saturation procedure provides adequate response during installation and increases the reliability of the coefficient of permeability determination in early *** inflow and outflow tests yielded similar results,indicating that careful execution of the test can lead to good test repeatability regardless of the loading *** sequences of alternated inflow and outflow tests have yielded similar results,indicating that soil reconsolidation and filter clogging were negligible in the tests *** are presented concerning the relationship between index parameters and the in situ coefficient of permeability for sarapuíII clay,which plot outside the range of existing databases.

关键词： Permeability test soft clay BAT probe Inflow and outflow tests

structural effects induced by dialysis-based purification of carbon nanomaterials

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Nano Materials science 2024年第4期6卷 475-483页

作者： A.D.Veloso A.M.Ferraria A.M.Botelho do rego A.s.Viana A.j.s.Fernandes A.j.Fielding r.A.Videira M.C.Oliveira CQ-Vr and Chemistry Department University of Trás-os-Montes e Alto Douro BsIrG iBB-Institute for Bioengineering and BiosciencesDepartment of Chemical Engineeringand Associate Laboratory i4HB-Institute for Health and BioeconomyInstituto Superior TécnicoUniversidade de Lisboa Centro de Química Estrutural Institute of Molecular SciencesDepartamento de Química e BioquímicaFaculdade de CiênciasUniversidade de Lisboa I3N and Physics Department University of AveiroCampus de Santiago Faculty of science Pharmacy and Biomolecular SchoolLiverpool John Moores University rEQUIMTE/LAQV Laborat orio de FarmacognosiaDepartamento de QuímicaFaculdade de Farm aciaUniversidade do Porto

Dialysis plays a crucial role in the purification of nanomaterials but its impact on the structural properties of carbon nanomaterials was never ***,a carbon-based nanomaterial generated electrochemically in potassium phosphate buffer,was characterized before and after dialysis against pure *** is shown that dialysis affects the size of the carbon domains,structural organization,surface functionalization,oxidation degree of carbon,and grade of ***,dialysis drives the nanomaterial organization from discrete roundish carbon domains,with sizes ranging from 70 to 160 nm,towards linear stacking structures of small nanoparticles （rallel,alcohol and ether （epoxide） surface groups evolve into more oxidized carbon groups （e.g.,ketone and ester groups）.Investigation of the as-prepared nanomaterial by electron paramagnetic resonance （EPr） revealed a resonance signal consistent with carbon-oxygen centred ***,this study brings to light the selective affinity of the carbon nanomaterial under study to capture Na+ions,a property greatly enhanced by the dialysis process,and its high ability to trap oxygen,particularly before *** findings open new perspectives for the application of carbon-based nanomaterials and raise awareness of the importance of structural changes that can occur during the purification of carbon-based nanomaterials.

关键词： Nanocarbon surface functionalization NMr XPs Hydrophilic carbon Paramagnetic

Generalized polynomial chaos expansion by reanalysis using static condensation based on substructuring

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

Applied Mathematics and Mechanics(English Edition) 2024年第5期45卷 819-836页

作者： D.LEE s.CHANG j.LEE Department of Automotive Engineering Hanyang UniversitySeoul 04763Republic of Korea school of Mechanical Engineering Chungnam National UniversityDaejeon 34134Republic of Korea Department of Mechanical Robotics and Energy EngineeringDongguk UniversitySeoul 04620Republic of Korea

This paper presents a new computational method for forward uncertainty quantification(UQ)analyses on large-scale structural systems in the presence of arbitrary and dependent random *** method consists of a generalized polynomial chaos expansion(GPCE)for statistical moment and reliability analyses associated with the stochastic output and a static reanalysis method to generate the input-output data *** the reanalysis,we employ substructuring for a structure to isolate its local regions that vary due to random *** allows for avoiding repeated computations of invariant substructures while generating the input-output data *** substructuring with static condensation further improves the computational efficiency of the reanalysis without losing ***,the GPCE with the static reanalysis method can achieve significant computational saving,thus mitigating the curse of dimensionality to some degree for UQ under high-dimensional *** numerical results obtained from a simple structure indicate that the proposed method for UQ produces accurate solutions more efficiently than the GPCE using full finite element analyses(FEAs).We also demonstrate the efficiency and scalability of the proposed method by executing UQ for a large-scale wing-box structure under ten-dimensional(all-dependent)random inputs.

关键词： forward uncertainty quantification(UQ) generalized polynomial chaos expansion(GPCE) static reanalysis method static condensation substructuring

Atomistic Investigation of shock-Induced Amorphization within Micro-shear Bands in Hexagonal Close-Packed Titanium

在线全文

学校读者我要写书评

暂无评论

Acta Metallurgica sinica(English Letters) 2024年第9期37卷 1590-1600页

作者： Z.C.Meng K.G.Wang T.Ali D.Li C.G.Bai D.s.Xu s.j.Li A.H.Feng G.j.Cao j.H.Yao Q.B.Fan H.Wang r.Yang Institute of Metal research Chinese Academy of SciencesShenyang 110016China school of Materials science and Engineering University of Science and Technology of ChinaShenyang 110016China Interdisciplinary Centre for Additive Manufacturing(ICAM) School of Materials and ChemistryUniversity of Shanghai for Science and TechnologyShanghai 200093China school of Materials science and Engineering Tongji UniversityShanghai 201804China Key Laboratory for Light-Weight Materials Nanjing Tech UniversityNanjing 210009China National Key Laboratory of science and Technology on Materials Under shock and Impact School of Materials Science and EngineeringBeijing Institute of TechnologyBeijing 100081China Beijing Institute of Technology Chongqing Innovation Center Chongqing 401135China

The mechanical response of a single crystal titanium sample against(0001)α surface impact was investigated using molecular dynamics ***,non-uniform plastic deformation was observed in the *** high strain rates,amorphization occurred near the edge of the contact region where severe shear strain induced a large number of stacking faults(sFs)and *** contrast,the central part of the contact region underwent less deformation with significantly fewer ***,instead of amorphization by consuming sFs and dislocations,there was a gradual increase in the density of dislocations and sFs during the process of *** local amorphous regions eventually grew into shear bands.

关键词： shock compression Amorphization shear band Titanium Molecular dynamics

Comparative analysis of microstructure,mechanical,and corrosion properties of biodegradable Mg-3Y alloy prepared by selective laser melting and spark plasma sintering

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

journal of Magnesium and Alloys 2024年第4期12卷 1496-1510页

作者： P.Minárik M.Zemková s.Šašek j.Dittrich M.Knapek F.Lukáˇc D.Koutný j.jaroš r.Král Faculty of Mathematics and Physics Charles UniversityKe Karlovu 5Praha 12116Czech Republic research Centre University ofŽilinaUniverzitná8215/1Žilina 01026Slovakia Institute of Plasma Physics of the Czech Academy of sciences Za Slovankou 1782/318200 Praha 8Czech Republic Institute of Machine and Industrial Design Brno University of TechnologyTechnická2896/2Brno 61669Czech Republic

This work explored possibilities of biodegradable magnesium alloy Mg-3Y preparation by two modern powder metallurgy techniques–spark plasma sintering(sps)and selective laser melting(sLM).The powder material was consolidated by both methods utilising optimised parameters,which led to very low porosity(∼0.3%)in the sLM material and unmeasurably low porosity in the sps *** main aim of the study was the thorough microstructure characterisation and interrelation between the microstructure and the functional properties,such as mechanical strength,deformability,and corrosion *** materials showed comparable strength of∼110 MPa in tension and compression and relatively good deformability of∼9%and∼21%for the sLM and sps materials,*** corrosion resistance of the sps material in 0.1 M NaCl solution was superior to the sLM one and comparable to the conventional extruded *** digital image correlation during loading and the cross-section analysis of the corrosion layers revealed that the residual porosity and large strained grains have the dominant negative effect on the functional properties of the sLM *** the other hand,one of the primary outcomes of this study is that the sps consolidation method is very effective in the preparation of the W3 biodegradable alloy,resulting in material with convenient mechanical and degradation properties that might find practical applications.

关键词： Magnesium Yttrium Powder metallurgy Microstructure Mechanical strength Corrosion resistance

Complexed amino acid minerals ***-glycinate chelated minerals:Impact on the performance of old laying hens

在线全文

学校读者我要写书评

暂无评论

Animal Nutrition 2024年第1期16卷 395-408页

作者： Marcos j.B.santos Maria C.M.M.Ludke Leandro M.silva Carlos B.V.rabello Mércia r.Barros Fabiano s.Costa Clariana s.santos jamille s.s.Wanderley Department of Animal science Rural Federal University of PernambucoRecifePEBrazil Department of Veterinary science Rural Federal University of PernambucoRecifePEBrazil

The present study was to evaluate the effect of trace minerals(Zn,Mn,and Cu)from complexed amino acid minerals(ZMCAA)and bis-glycinate chelated minerals(ZMCGly)in laying hen diets on performance,internal and external egg quality,yolk mineral deposition,intestinal morphometry,and bone *** 78 to 98 weeks of age,400 White LsL-Lite strain laying hens were distributed in a randomized design with 4 treatments with 10 replicates per *** were distributed in a 2×2 factorial arrangement using either Zn,Mn,and Cu of ZMCAA or ZMCGly source at 2 levels:low(20,20,and 3.5 mg/kg of Zn,Mn,and Cu,respectively)or high(40,40,and 7 mg/kg of Zn,Mn,and Cu,respectively).The analysis of variance was performed,and in cases where differences were observed,the means were compared using Tukey?s test(Psource and level of trace mineral supplementation had a significant impact on the performance of laying *** fed ZMCAA had higher egg production(P=0.01),egg weight(P=0.02),egg mass(P=0.01),and lower feed conversion ratio(P=0.05)compared to those fed *** ZMCAA supplementation showed higher albumen height(P=0.01),albumen weight(P=0.01),and eggshell thickness(Psition of Zn(Pnd Cu(Ps greater for hens received *** weight(P=0.04)and bone densitometry(Pre higher with ZMCAA *** the small intestine,ZMCAA resulted in longer villi(P=0.02)and shorter crypt depth(P=0.01)in the *** and ileum measurements were influenced by the level and source of trace minerals(Ps fed ZMCAA exhibited superior performance,egg quality,deposition of trace minerals in the egg yolk,and bone density compared to hens fed *** this study,older laying hens supplemented with ZMCAA at lower levels demonstrated adequate levels of supplementation.

关键词： Bis-glycinates Metal-amino acids radiodensity Trace minerals

Background removal from global auroral images:Data-driven dayglow modeling

在线全文

学校读者我要写书评

暂无评论

Earth and Planetary Physics 2024年第1期8卷 247-257页

作者： A.Ohma M.Madelaire K.M.Laundal j.P.reistad s.M.Hatch s.Gasparini s.j.Walker Birkeland Centre for space science Department of Physics and TechnologyUniversity of BergenBergenNorway

Global images of auroras obtained by cameras on spacecraft are a key tool for studying the near-Earth ***,the cameras are sensitive not only to auroral emissions produced by precipitating particles,but also to dayglow emissions produced by photoelectrons induced by *** emissions and scattered sunlight can contribute to the background *** fully utilize such images in space science,background contamination must be removed to isolate the auroral *** we outline a data-driven approach to modeling the background intensity in multiple images by formulating linear inverse problems based on B-splines and spherical *** approach is robust,flexible,and iteratively deselects outliers,such as auroral *** final model is smooth across the terminator and accounts for slow temporal variations and large-scale asymmetries in the *** demonstrate the model by using the three far ultraviolet cameras on the Imager for Magnetopause-to-Aurora Global Exploration(IMAGE)*** method can be applied to historical missions and is relevant for upcoming missions,such as the solar wind Magnetosphere Ionosphere Link Explorer(sMILE)mission.

关键词： aurora dayglow modeling global auroral images far ultraviolet images dayglow removal