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Design and Simulation of a Novel Pneumotronic System Aimed to the Investigation of Vascular Phenomena Induced by Limb Compression

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Journal of Bionic Engineering 2019年第3期16卷 550-562页

作者： Carlo Ferraresi Carlo De Benedictis Daniela Maffiodo Walter Franco Alessandro Messere Raffaele Pertusio Silvestro Roatta department of mechanical and aerospace Engineering Politecnico di Torino Torino 10129 Italy department of Neuroscience University of Torino Torino 10125 Italy

Intermittent Pneumatic Compression (IPC) devices can be used to analyze the mechanisms underlying several vascular phenomena, such as hyperaemia. Commercial devices have limited dynamics and do not allow the delivery of customizable compressive pressure patterns, making the analysis of such phenomena difficult, which may require the application of long stimulations with low amplitude as well as fast compressions with higher pressure level. To overcome these issues, a novel pneumotronic device aimed to the investigation of the physiological effects induced by limb compressions is conceived and presented in this work. The design requirements of the system, capable of delivering customizable compressive patterns in the range 0 mmHg-200 mmHg, are outlined. The final prototype architecture is described, and a mathematical model of the entire system, also including the interaction between the device and the limb tissues, is proposed. The performance of the device was evaluated in several conditions by means of simulations, whose results were compared to the data collected from experimental trials in order to validate the model. The outcomes of both experimentation and simulation trials proved the effectiveness of the solution proposed. A possible employment of this device for the investigation of the rapid compression-induced hyperaemia is presented. Other potential applications concern the wide range of intermittent-pneumatic compression treatments.

关键词： pneumotronic system pneutronics hyperaemia limb compression pneumatic system modeling human-machine interaction

Microstructural analysis and hot corrosion behavior of HVOF-sprayed Ni–22Cr–10Al–1Y and Ni–22Cr–10Al–1Y–SiC(N) coatings on ASTM-SA213-T22 steel

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International Journal of Minerals,Metallurgy and Materials 2020年第3期27卷 401-416页

作者： Gurmail Singh Niraj Bala Vikas Chawla department of mechanical Engineering IKGPTUJalandhar 144603PunjabIndia department of aerospace Engineering Chandigarh UniversityGharuan 140413PunjabIndia department of mechanical Engineering BBSBECFatehgarh Sahib 140407PunjabIndia

The present paper deals with the investigation of microstructure and high-temperature hot corrosion behavior of high-velocity oxy fuel(HVOF)-produced coatings. Two powder coating compositions, namely, Ni22Cr10Al1Y alloy powder and Ni22Cr10Al1Y(80 wt%;microsized)–silicon carbide(SiC)(20 wt%;nano(N)) powder, were deposited on a T-22 boiler tube steel. The hot corrosion behavior of bare and coated steels was tested at 900°C for 50 cycles in Na2SO4–60 wt%V2O5 molten-salt environment. The kinetics of corrosion was established with weight change measurements after each cycle. The microporosity and microhardness of the as-coated samples have been reported. The X-ray diffraction,field emission-scanning electron microscopy/energy dispersive spectroscopy, and X-ray mapping characterization techniques have been utilized for structural analysis of the as-coated and hot-corroded samples. The results showed that both coatings were deposited with a porosity less than2%. Both coated samples revealed the development of harder surfaces than the substrate. During hot corrosion testing, the bare T22 steel showed an accelerated corrosion in comparison with its coated counterparts. The HVOF-sprayed coatings were befitted effectively by maintaining their adherence during testing. The Ni22Cr10Al1Y–20 wt%SiC(N) composite coating was more effective than the Ni–22Cr–10Al–1Y coating against corrosion in the high-temperature fluxing process.

关键词： high-velocity oxy fuel thermal spray hot corrosion oxide scale nano-structured coating

Adaptive Control of a Two-Link Robot Using Batch Least-Square Identifier

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IEEE/CAA Journal of Automatica Sinica 2021年第1期8卷 86-93页

作者： Mostafa Bagheri Iasson Karafyllis Peiman Naseradinmousavi Miroslav Krstić the department of mechanical and aerospace Engineering University of California San Diego and San Diego State UniversityLa JollaCA 92037 USA the department of Mathematics National Technical University of AthensAthina 10682Greece the department of mechanical Engineering San DiegoCA 92182 USA the department of mechanical and aerospace Engineering University of California San DiegoLa JollaCA 92037 USA

We design a regulation-triggered adaptive controller for robot manipulators to efficiently estimate unknown parameters and to achieve asymptotic stability in the presence of coupled *** manipulators are widely used in telemanipulation systems where they are subject to model and environmental *** conventional control algorithms on such systems can cause not only poor control performance,but also expensive computational costs and catastrophic ***,system uncertainties need to be estimated through designing a computationally efficient adaptive control *** focus on robot manipulators as an example of a highly nonlinear *** a case study,a 2-DOF manipulator subject to four parametric uncertainties is ***,the dynamic equations of the manipulator are derived,and the corresponding regressor matrix is constructed for the unknown *** a general nonlinear system,a theorem is presented to guarantee the asymptotic stability of the system and the convergence of parameters'***,simulation results are discussed for a two-link manipulator,and the performance of the proposed scheme is thoroughly evaluated.

关键词： Backstepping least-square identifier robot manipulators trigger-based adaptive control

Fluorescent digital image correlation techniques in experimental mechanics

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Science China(Technological Sciences) 2018年第1期61卷 21-36页

作者： HU ZhenXing XU TingGe WANG XueMin XIE ZhiMing LUO HuiYang HE Yong GUO Lei LI YuanPing GAN RongZhu LU HongBing department of mechanical Engineering University of Texas at Dallas department of Civil Engineering Yancheng Institute of Technology School of Mechanics and Construction Engineering Jinan University School of aerospace and mechanical Engineering University of Oklahoma

White light has often been used for surface illumination to acquire images for digital image correlation （DIC） analysis. In recent years, fluorescent imaging technique has been introduced for illumination, surface deformation and topography measurements with applications on various materials including biomaterials （biofilms, etc.） at the microscale. Traditional imaging, with the use of white light, encounters technical issues such as specular reflection owing to moisture or smooth shiny surfaces （e.g., metallic or glass surfaces）. As an altemative to white light, fluorescent imaging serves as a solution to resolve the issues of specular reflection. Fluorescent DIC techniques, especially the fluorescent stereo DIC, allow 3D surface profilometry and deformation measurements at the microscale and submicron scale. Fluorescent stereo imaging under a microscope utilizes emission wavelengths that are different from illumination wavelengths to ensure clear images on any surface that might give reflections at certain angles when white light is used, allowing accurate metrology and deformation measurement. In addition microscopic fluorescent imaging provides nanoscale resolutions surpassing Abbe＇s diffraction limit. This paper provides a review of the recent advances in fluorescent DIC.

关键词： digital image correlation stereo digital image correlation fluorescent imaging fluorescent stereo microscopy 3D profilometry deformation measurement

Lagrangian-based investigation of multiphase flows by finite-timeLyapunov exponents

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Acta Mechanica Sinica 2012年第3期28卷 612-624页

作者： Jia-Ning Tang Chien-Chou Tseng Ning-FeiWang School of aerospace Engineering Beijing Institute of Technology100081 Beijing China department of mechanical and Electro-mechanical Engineering National Taiwan Sun Yat-Sen UniversityKaohsiung Taiwan China department of aerospace Engineering University of Michigan Ann ArborM148109 USA

Multiphase flows are ubiquitous in our daily life and engineering applications. It is important to investigate the flow structures to predict their dynamical behaviors ef- fectively. Lagrangian coherent structures （LCS） defined by the ridges of the finite-time Lyapunov exponent （FTLE） is utilized in this study to elucidate the multiphase interactions in gaseous jets injected into water and time-dependent turbu- lent cavitation under the framework of Navier-Stokes flow computations. For the gaseous jets injected into water, the highlighted phenomena of the jet transportation can be observed by the LCS method, including expansion, bulge, necking/breaking, and back-attack. Besides, the observation of the LCS reveals that the back-attack phenomenon arises from the fact that the injected gas has difficulties to move toward downstream re- gion after the necking/breaking. For the turbulent cavitating flow, the ridge of the FTLE field can form a LCS to capture the front and boundary of the re-entraint jet when the ad- verse pressure gradient is strong enough. It represents a bar- rier between particles trapped inside the circulation region and those moving downstream. The results indicate that the FFLE field has the potential to identify the structures of mul- tiphase flows, and the LCS can capture the interface/barrier or the vortex/circulation region.

关键词： Finite-time Lyapunov exponents Lagrangiancoherent structures Multiphase flow Gaseous jets injectedinto water Cavitation

A new localization theory of adaptive machining of near-net-shape blades

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Chinese Journal of Aeronautics 2021年第6期34卷 18-32页

作者： Neng WAN Xiaogang SHEN Zhiyong CHANG Zezhong C.CHEN department of mechanical Engineering Northwestern Polytechnical UniversityXi'an 710072China department of mechanical Industrial and Aerospace EngineeringConcordia UniversityMontrealQuebec H3G IMSCanada

In the fabrication of aero-engine blades,a great deal is gained when massive material removal is avoided at the end of the process,and as little as possible material is left on the blade *** to the uncertainty of pre-process,the billet shapes are ***,the near-net-shape billet doesn’t cover the blade design surface to be ***,blade localization is necessary for these billets before the *** conventional localization methods,the design surface’s location focused on guaranteeing enough material to be ***,because the to-becut surface is in near-net and free-form shape,it is difficult to find a valid localized surface model to generate the tool *** from the localized surface is taken as rigid in previous investigation,it is allowed to deviate from the design surface no more than the tolerance *** term of this principle,the tolerance band is utilized to promote localization ability.A series of optimization models with different priorities is established to avoid the abandonment expensive blade ***,with the experiments performed on the near-net-shape blades,the blade localization theory and the promotion of localization ability are verified.

关键词： Blade localization Curvature constraint Machining surface Near-net-shape blade Tolerance constraint

Differences of grain-refining effect of Sc and Ti additions in aluminum by empirical electron theory analysis

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Transactions of Nonferrous Metals Society of China 2010年第3期20卷 465-470页

作者：叶益聪何良菊李培杰 National Center of Novel Materials for International Research Department of Mechanical EngineeringTsinghua University School of aerospace Tsinghua University

The differences of grain-refining effect between Sc and Ti additions in aluminum,which cannot be substantially explained by traditional theories,were carefully *** empirical electron theory(EET) of solids and molecules was employed to calculate the valence electron structures(VES) of Al3Ti and *** conclusions can be drawn that,in the two alloys Al-Ti and Al-Sc,the different valence electron structures of Al3Ti and Al3Sc and the consequent differences of growth habit of the two particles,and the different interfacial electron density between particles and matrix fundamentally lead to the differences of grain-refining effect between Sc and Ti additions on aluminum and make Sr the better grain-refiner of aluminum.

关键词： grain refining empirical electron theory(EET) valence electron structure(VES) Al3Sc Al3Ti

Fractional Dynamics of Fluid-Conveying Pipes Made of Polymer-Like Materials

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Acta Mechanica Solida Sinica 2018年第2期31卷 243-258页

作者： Ye Tang Tianzhi Yang Bo Fang School of mechanical and Automotive Engineering Anhui Polytechnic University School of aerospace Engineering Shenyang Aerospace University department of Mechanics Tianjin University School of Astronautics Harbin Institute of Technology

The fluid-conveying pipes made of polymer-like materials are widely applied in engineering fields. However, the fractional dynamics of fluid-solid interaction remain unknown. In this work, the fractional dynamics of the pipes subjected to the excitation of supporting foun- dation are studied. A new nonlinear, fractional-order dynamic model is presented. The method of multiple scales is adopted directly to solve the model for the case of primary resonances. Numerical results are presented to show the effects of fractional order, foundation vibration, and other physical parameters on the steady-state response and stability.

关键词： Fluid-conveying pipes Fractional dynamics Method of multiple scales Polymer- like materials

Single-atom spintronics

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中国有色金属学会会刊：英文版 2006年第B1期16卷 146-153页

作者： Susan Z.HUA Matthew R.SULL IVAN Jason N.ARMSTRONG Materials Program Mechanical and Aerospace Engineering DepartmentState University of New York at BuffaloBuffaloNY 14260USA

Recent work on magnetic quantum point contacts (QPCs) was discussed. Complete magnetoresistance loops across Co QPCs as small as a single atom was measured. The remarkable feature of these QPCs is the rapid oscillatory decay in magnetoresistance with the increase of contact size. In addition, stepwise or quantum magnetoresistance loops are observed, resulting from varying transmission probability of the available discrete conductance channels because the sample is cycled between the ferromagnetic (F) and antiferromagnetic (AF) aligned states. Quantized conductance combined with spin dependent transmission of electron waves gives rise to a multi-channel system with a quantum domain wall acting as a valve, i.e., a quantum spin-valve. Behavior of a few-atom QPC is built on the behavior of a single-atom QPC and hence the summarization of results as ‘single-atom spintronics’. An evolutionary trace of spin-dependent electron transmission from a single atom to bulk is provided, the requisite hallmarks of artefact-free magnetoresistance is established across a QPC – stepwise or quantum magnetoresistance loops and size dependent oscillatory magnetoresistance.

关键词：单原子自旋电子学量子点接触电子波导振荡磁阻