Letteratura scientifica selezionata sul tema "Micro-Attentions"
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Articoli di riviste sul tema "Micro-Attentions"
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Luo, Liang, Zheng Yi Jiang, Dong Bin Wei e Xiaofeng He. "Study on Micro Hydroforming of Metals". Advanced Materials Research 887-888 (febbraio 2014): 1133–38. http://dx.doi.org/10.4028/www.scientific.net/amr.887-888.1133.
Testo completoAbstract (sommario):
Micro hydroforming has an ability to manufacture complex 3D micro parts at a high production rate and has drawn increasing attentions. Brief understanding of macro hydroforming, for instance, deep drawing, is necessary to understand the principle of micro hydroforming. Then, special phenomena, such as size effects, occurred at micro scale are discussed and the related theories explaining these phenomena are introduced. Based on the similarities and differences between micro and macro hydroforming, experiments and simulation which consider the size effects are reviewed.
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Takalkar, Madhumita A., Selvarajah Thuseethan, Sutharshan Rajasegarar, Zenon Chaczko, Min Xu e John Yearwood. "LGAttNet: Automatic micro-expression detection using dual-stream local and global attentions". Knowledge-Based Systems 212 (gennaio 2021): 106566. http://dx.doi.org/10.1016/j.knosys.2020.106566.
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Huang, Bo Wun, Jung Ge Tseng e Chien Hua Chang. "Finite Element Analysis on Vibration of a Piezoelectric Micro Pump". Applied Mechanics and Materials 789-790 (settembre 2015): 861–64. http://dx.doi.org/10.4028/www.scientific.net/amm.789-790.861.
Testo completoAbstract (sommario):
Due to the rise of biological and MEMS technology in recent years, some micro flow system components have been paid attentions to developed by many investigators. The importance of micro-pumps manufactured is higher than the other part of micro flow system since it is the power source of the entire micro-flow system and responsible for driving working fluid in the microfluidic system. In actual operation, the instability and bad dynamic characteristics of the micro-pump will cause larger fluid flow mobility error, such as transport behavior and response procedures failure, etc., and even damage the microfluidic system. Therefore, to investigate the stability and dynamic characteristics of a micro pump is necessary. The miniature piezoelectric film micro-pump, made by Microjet Technology Co., Ltd., is employed to study in this work. The computer graphics software SolidWorks is used to build the model of the micro pump. Then, The Finite element analysis (FEA), ANSYS Workbench, is also employed to analyze the dynamic characteristics of this micro pump.
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Liu, Ting Ting, Wei Su, Tao Yang, Bin Han e Chao Wang. "Research on Characteristics of Mercury Droplet Flow in Micro Acceleration Switch". Key Engineering Materials 562-565 (luglio 2013): 328–33. http://dx.doi.org/10.4028/www.scientific.net/kem.562-565.328.
Testo completoAbstract (sommario):
Unlike the solid-solid contact of traditional micro acceleration switch, liquid metal can be utilized to solve the disadvantage of solid-solid contact, such as contact wear and signal bounce. Liquid-metal micro switches have demonstrated no contact bounce, low switch-on time, low contact resistance, long life, and the capability to handle large currents. So the liquid-metal micro acceleration switches have attracted researcher’s attentions increasingly. To investigate the flow characteristics of mercury droplet in micro acceleration switch, this paper establishes numerical models of micro acceleration switch by using FLUENT. The effect of contact angle, droplet volume and temperature are discussed in this paper. Based on the VOF-CSF model of FLUENT, a serial of simulations were performed. The simulation results show that the influence of contact angle and droplet volume on flow characteristics is serious, and the influence of temperature is small. As compared with theoretical analysis, simulations are in good agreement with theoretical analysis.
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Luo, Yuehao, Robert Smith e Lork Green. "Exploring instantaneous micro-imprinting technology on semi-cured epoxy resin coating based on relationship between forming precision and curing degree". Chemical Industry and Chemical Engineering Quarterly 22, n. 1 (2016): 47–53. http://dx.doi.org/10.2298/ciceq150119018l.
Testo completoAbstract (sommario):
Nano/micro-imprinting technology base on polymer material coating has attracted the increasing attentions throughout the world in the past several decades, and it is progressively developing into the hot topic at present, in which, how to improve the manufacturing efficiency is becoming the urgent issue to be resolved. Polymer?s curing process is exactly complicated and sophisticated, which involves simultaneously performing physical and chemical changes, when the curing reaction reaches certain level, the system will abruptly transform into insoluble, non-melting gel with rapidly increased viscosity and rigidity, which can generate fixed deformation under persistent external pressure. In this paper, the plastic deformation capacity of epoxy resin in the curing process is investigated by the micro-dimple imprinting experiment, and the relationship between forming precision and curing degree is ascertained adopting the DSC (differential scanning calorimetry) method. In addition, the instantaneous micro-imprinting technology based on the micro-grooves is explored, and the experimental results indicate that the forming precision can surpass 90%. The paper will establish a novel avenue to apply the nano/micro imprinting technology into practical engineering.
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Keighobadi, J., J. Faraji e S. Rafatnia. "Chaos Control of Atomic Force Microscope System Using Nonlinear Model Predictive Control". Journal of Mechanics 33, n. 3 (13 settembre 2016): 405–15. http://dx.doi.org/10.1017/jmech.2016.89.
Testo completoAbstract (sommario):
AbstractOwing to robust and optimal specification, model predictive control method has received wide attentions over recent years. Since in certain operational conditions, an Atomic/scanning Force Microscope (AFM) shows chaos behavior, the chaos feedback control of the AFM system is considered. According to the nonlinear model of forces interacting between the tip of micro cantilever and the substrate of AFM; the nonlinear control methods are proposed. In the paper, the chaos control of a micro cantilever AFM based on the nonlinear model predictive control (NMPC) technique is presented. Through software simulation results, the effectiveness of the designed NMPC of the AFM is assessed. The simulation results together with analytical stability proofs indicate that the proposed method is effective in keeping the system in a stable range.
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Luo, Liang, Zheng Yi Jiang, Dong Bin Wei, Hideki Sato, Tsuyoshi Furushima e Ken-Ichi Manabe. "A Numerical Study of Micro Hydro Deep Drawing of SUS304 Sheets". Applied Mechanics and Materials 846 (luglio 2016): 524–29. http://dx.doi.org/10.4028/www.scientific.net/amm.846.524.
Testo completoAbstract (sommario):
Micro forming is a promising technology and has drawn global attentions due to the urgent requirements on miniaturised products. Micro hydro deep drawing (MHDD) is a typical micro forming method and its products are widely applied in various fields, such as micro electro-mechanical systems (MEMS), medical and aerospace areas. However, tiny sizes of both products and tools are obstacles to investigate this novel technology. Therefore, finite element method (FEM) is adopted and modified to study the influence of processing parameters on micro drawing process and produced products. In this study, a normal hydro deep drawing model was developed, and then a voronoi blank model was generated to consider the size effects of materials. Additionally, a surface layer model was created based on the voronoi blank model. Therefore, the open and closed lubricant theory can be fulfilled and friction behaviour in MHDD can be considered. Subsequently, different processing parameters, such as hydraulic pressure and material inhomogeneity, were investigated. Simulation results indicate that a proper hydraulic pressure improves drawability and shape accuracy of the drawn cups. Moreover, material inhomogeneity affects the quality of drawn cups.
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Wang, Jingjing, Baozheng Xu, Yinfang Zhu e Junyuan Zhao. "Microcantilever sensors for biochemical detection". Journal of Semiconductors 44, n. 2 (1 febbraio 2023): 023105. http://dx.doi.org/10.1088/1674-4926/44/2/023105.
Testo completoAbstract (sommario):
Abstract Microcantilever is one of the most popular miniaturized structures in micro-electromechanical systems (MEMS). Sensors based on microcantilever are ideal for biochemical detection, since they have high sensitivity, high throughput, good specification, fast response, thus have attracted extensive attentions. A number of devices that are based on static deflections or shifts of resonant frequency of the cantilevers responding to analyte attachment have been demonstrated. This review comprehensively presents state of art of microcantilever sensors working in gaseous and aqueous environments and highlights the challenges and opportunities of microcantilever biochemical sensors.
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Yang, Wenqing, Liguang Wang e Bifeng Song. "Dove: A biomimetic flapping-wing micro air vehicle". International Journal of Micro Air Vehicles 10, n. 1 (9 ottobre 2017): 70–84. http://dx.doi.org/10.1177/1756829317734837.
Testo completoAbstract (sommario):
This paper describes the design and development of the Dove, a flapping-wing micro air vehicle (FWMAV), which was developed in Northwestern Polytechnical University. FWMAVs have attracted international attentions since the past two decades. Since some achievements have been obtained, such as the capability of supporting an air vehicle to fly, our research goal was to design an FWMAV that has the ability to accomplish a task. Main investigations were presented in this paper, including the flexible wing design, the flapping mechanism design, and the on-board avionics development. The current Dove has a mass of 220 g, a wingspan of 50 cm, and the ability of operating fully autonomously, flying lasts half an hour, and transmitting live stabilized color video to a ground station over 4 km away.
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Zhang, Xiao Quan, e L. Tian. "Three-Dimensional Simulation of Micro Air Vehicles with Low-Aspect-Ratio Wings". Key Engineering Materials 339 (maggio 2007): 377–81. http://dx.doi.org/10.4028/www.scientific.net/kem.339.377.
Testo completoAbstract (sommario):
Micro Air Vehicles (MAVs) are catching more and more attentions for their broad application in civilian and military fields. Since the theories on the aerodynamics of low Reynolds number are not maturely presented and the wind-tunnel experiments cost long periods and great expenses. The numerical simulation based on computational fluid dynamics (CFD) is a good method to choose. Through three-dimensional simulation of the wings, the aerodynamic characteristics of the flows around MAVs can be easily obtained. The tip vortices produced around low-Reynolds-number and low-aspect-ratio wings can increase the lift and stall angles. The result of numerical simulation can be used as references of theory analysis and wind-tunnel experiments.
Tesi sul tema "Micro-Attentions"
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Rached, Estelle. "Le devenir humain dans et pour l’incertitude : la qualité en éducation. Cas des établissements scolaires du second degré au Liban". Electronic Thesis or Diss., Université de Lorraine, 2024. http://www.theses.fr/2024LORR0091.
Testo completoAbstract (sommario):
La présente thèse questionne la qualité en éducation en abordant le concept de « l’a-qualité », par analogie au modèle de « l’a-synthèse » (Perez, 2008). Le préfixe « a » est suspensif, invitant à suspendre la qualité éducative du point de vue normatif pour l’interroger au niveau de son construit théorique. L’a-qualité est abordée dans ses deux facettes de micro-attentions et de micro-violences dans le pays du Cèdre, en proie à de violentes crises. L’objectif de notre thèse vise à lever le voile sur la place de l’humain qui interagit avec autrui et avec l’environnement, constituant l’angle mort de la qualité et le seul rempart contre la mouvance sociétale. La question de recherche suivante guide l’étude : Quelle a-qualité humaniste peut-elle définir l’angle mort de la qualité d’un établissement scolaire afin de répondre à l’incertitude du contexte libanais ? Nous avançons l’hypothèse que l’a-qualité humaniste se centre sur la formation holistique des acteurs éducatifs, conjugue leurs capacités distinctives et développe une institution éco-émergente lui permettant de relever les défis du contexte incertain. Notre thèse s’inscrit dans une approche mixte, selon le design séquentiel explicatif de Creswell (2014), dans une complémentarité des données quantitatives et qualitatives. Les résultats dévoilent que l’a-qualité est davantage perçue dans le contexte incertain par l’absence de micro-violences que par la présence de micro-attentions. Face aux mutations sociétales, les acteurs éducatifs semblent plus sensibles à la micro-violence qu’à la micro-attention, les pratiques dommageables pour les humains gardant des traces souvent indélébiles. Dans ce sens, l’école en devenir s’inscrit dans son contexte, en devenant éco-émergente, apte à transformer les obstacles en opportunités pour apprendre et se développer. Elle forme les acteurs éducatifs aux compétences de vie, soucieuse de leur bien-être, au sein d’une altérité bienveillante, valorisant la singularité de chacun, dans une intelligence collective (De Ketele, 2020a) au service d’un monde commun et non uniforme (Mutuale, 2020)This thesis explores education quality by introducing the concept of "a-quality," akin to the model of "a-synthesis" (Perez, 2008). The prefix "a" is suspensive, inviting us to explore educational quality by examining it at the level of its theoretical constructs. A-quality is approached in its dual aspects of micro-attention and micro-violence in Lebanon, beset by severe crises. Our thesis aims to unveil the role of the human who interacts with others and with the environment, an overlooked aspect of quality and the sole defence against societal flux. The research question that guides this study is: What humanistic a-quality aspects can define the blind spot of school quality to address the uncertainty of the Lebanese context? We hypothesize that humanistic a-quality focuses on the holistic development of educational actors, harnesses their distinctive capacities, and cultivates an eco-emergent institution to meet the challenges in an uncertain context. Our thesis employs a mixed-methods approach, following Creswell's (2014) sequential explanatory design, combining quantitative and qualitative data. The findings reveal that a-quality is perceived more in uncertain contexts by the absence of micro-violence rather than by the presence of micro-attentions. Faced with societal shifts, educational actors appear more attuned to micro-violence than micro-attention, as harmful practices leave often indelible marks on humans. Therefore, the evolving school embeds itself in its context, becoming eco-emergent, and capable of transforming obstacles into learning opportunities and growth. It empowers educational actors with life skills, mindful of their well-being within a benevolent otherness, valuing everyone’s uniqueness within a collective intelligence (De Ketele, 2020a) serving the common good and a non-uniform world (Mutuale, 2020)
Capitoli di libri sul tema "Micro-Attentions"
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Hu, Liangxing, Nan Wang e Kai Tao. "Catalytic Micro/Nanomotors: Propulsion Mechanisms, Fabrication, Control, and Applications". In Smart Nanosystems for Biomedicine, Optoelectronics and Catalysis. IntechOpen, 2020. http://dx.doi.org/10.5772/intechopen.90456.
Testo completoAbstract (sommario):
Micro-/nanomotors are self-propelled micro-/nanomachines, which are capable of converting the surrounding fuels into mechanical movement or force. Inspired by naturally occurring biomolecular motor proteins, scientists extensively paid great attentions to synthetic micro-/nanomotors. Especially, a number of researchers devoted their efforts onto catalytic micro-/nanomotors. In the past few decades, several advanced developments and excellent contributions have been made in catalytic micro-/nanomotors. The future of this research field can be bright, but some major existing challenges such as biocompatible materials and fuels, smart controlling, and specifically practical applications are still required to be resolved. Therefore, it is essential for us to learn the state of the art of catalytic micro-/nanomotors. In this chapter, the propulsion mechanisms, fabrication methods, controlling strategies, and potential applications of catalytic micro-/nanomotors are presented and summarized.
Atti di convegni sul tema "Micro-Attentions"
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Zhang, Hangbin, Raymond K. Wong e Victor W. Chu. "Curvilinear Collaborative Metric Learning with Macro-micro Attentions". In 2021 International Joint Conference on Neural Networks (IJCNN). IEEE, 2021. http://dx.doi.org/10.1109/ijcnn52387.2021.9533945.
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Zeng, Taofang. "Phonon Heat Conduction in Micro- and Nano-Cylindrical and Spherical Media". In ASME 2002 International Mechanical Engineering Congress and Exposition. ASMEDC, 2002. http://dx.doi.org/10.1115/imece2002-32792.
Testo completoAbstract (sommario):
Phonon heat conduction in thin films and superlattices of dielectric materials has attracted extensive attentions in the past decade. Nonetheless, a wide range of micro- and nanoscale thermal problems is associated with non-planar geometries such as spherical and cylindrical media. With the rapid growth of research and development in nano-materials and nanostructures, understanding of heat transfer in micro- and nano-cylindrical and spherical media becomes important. Examples include cladding and coating for optic fibers and nanowires.
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Bhuyan, Manoj Kumar, Razvan Stoian e Koji Sugioka. "Nanoscale modification of glass via micro-explosion using ultrafast Bessel laser pulse". In JSAP-OSA Joint Symposia. Washington, D.C.: Optica Publishing Group, 2017. http://dx.doi.org/10.1364/jsap.2017.8p_a410_2.
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In the framework of laser-induced micro- and nanoscale material modification, we present results on ultrafast Bessel beam-glass interaction, inducing extended length scale material modification on single-shot basis. The possibility of high-level energy localization using non-diffractive Bessel beams has been shown using chirped pulses and moderate focusing conditions, drawing attentions in the fields of nonlinear optics and large volume material processing [1, 2]. Here, we show how ultrashort Bessel laser pulse interacts with fused silica glass in a tight focusing geometry and the follow-up material relaxation over a broad range of temporal domain i.e. ns – μs. The consequence of such interaction in terms of ultimate material transformation will be discussed.
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Hao, Wentao, Ling Tian e Bingshu Tong. "Macromodeling Method of Fluid-Structure Interacting MEMS Based on Modal Analysis and Proper Orthogonal Decomposition". In 2007 First International Conference on Integration and Commercialization of Micro and Nanosystems. ASMEDC, 2007. http://dx.doi.org/10.1115/mnc2007-21289.
Testo completoAbstract (sommario):
Because of their good performance to speed up MEMS system simulation processes, macromodels have aroused lots of attentions of scientists in the last decades. However, studies on FSI (Fluid-Structure Interaction) MEMS devices still can not satisfy the macromodeling requests because of the high complexity of fluid fields. A new method based on modal analysis and POD (Proper Orthogonal Decomposition) is tentatively put forward to reduce the order of FSI MEMS models. The structure macromodeling theory is firstly reviewed. Then the fluid field macromodeling approach is discussed in detail. At last, a 2D fixed-fixed micro-beam is analyzed and the results show that the macromodel extracted in this method can highly decrease the system degrees of freedom, while its precision is still comparable with that of detailed models.
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Liu, Jin, Moran Wang, Shiyi Chen e Mark O. Robbins. "Molecular Simulation of Electrokinetic Transport in Nanofluidics". In ASME 2009 Second International Conference on Micro/Nanoscale Heat and Mass Transfer. ASMEDC, 2009. http://dx.doi.org/10.1115/mnhmt2009-18422.
Testo completoAbstract (sommario):
Electrokinetic transport in nanofluidics has attracted many attentions in recent years due to its potential applications in biomedical analysis and energy conversion systems. The biggest challenge to model the electrokinetic transport using atomistic simulations is the extensive cost in calculation of the long-range electrostatic force between ions. In this work, we develop an efficient molecular approach to simulate electrokinetic transport in nano-scale. The long-range Coulombic interactions are treated using the Particle-Particle Particle-Mesh (P3M) scheme and the Poisson equation for electric potential is solved in physical space using an iterative multi-grid technique. We implement this approach to systematically investigate two examples: the electroosmotic flow in random rough channels and the electrowetting on dielectric (EWOD). Both cases pose important engineering applications as a mechanism for transporting small amount of liquid in micro and nano devices.
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Kobayashi, Isao, e Mitsutoshi Nakajima. "Micro/Nanochannel Emulsification for Generating Monosize Droplets". In ASME 2012 Third International Conference on Micro/Nanoscale Heat and Mass Transfer. American Society of Mechanical Engineers, 2012. http://dx.doi.org/10.1115/mnhmt2012-75238.
Testo completoAbstract (sommario):
Emulsification is an important process in various fields including foods, pharmaceuticals, cosmetics, and chemicals. Emulsification operation is commonly conducted using conventional emulsification devices, such as high-speed blenders, colloid mills, high-pressure homogenizers, and ultrasonic homogenizers. However, these emulsification devices result in the production of polydisperse emulsions with wide droplet size distributions and poor controllability in droplet size and its distribution. In contrast, monodisperse emulsions consisting of monosize droplets have received a great deal of attentions over the past decade due to their high-tech applications, e.g., monosize microparticles as spacers for electronic devices and monosize micro-carriers for drug delivery systems (DDS). Our group proposed microchannel (MC) emulsification as a promising technique to produce monodisperse emulsions in the mid 1990s. Micro/Nanochannel (MNC) emulsification enables generating monosize droplets with the smallest coefficient of variation (CV) of below 5% using MC and nanochannel (NC) arrays of unique geometry. The resultant droplet size, which ranged from 0.5 to 200 μm, can be precisely controlled by channel geometry. Droplet generation for MNC emulsification is very mild and does not require any external shear stress; a dispersed phase that passed through channels is transformed spontaneously into monosize droplets inside a continuous-phase domain. The aim of this paper is to present recent developments in MNC emulsification chips, particularly focusing on asymmetric straight-through MC arrays for large-scale production of monodisperse emulsions. Asymmetric straight-through MC array chips were fabricated using a silicon-on-insulator wafer. Numerous asymmetric straight-through MCs each consisting of a microslot and a narrow MC were positioned in the central region of the chip. Monosize droplets were stably generated via asymmetric straight-through MCs at high production rates. Below a critical droplet production rate, monosize droplets were generated via asymmetric straight-through MCs, with droplet size and size distribution independent of the droplet productivity. The use of a large asymmetric straight-through MC array chip achieved the mass production of monosize tetradecane oil droplets at ∼1 L/h. The simulation results using CFD (computational fluid dynamics) agreed well with the experimental results and provided useful information, such as the movement of the oil-water interface during droplet generation. Monosize submicron droplets were also obtained using NC emulsification chips made of single-crystal silicon.
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Jafari, Somaye, Masoud Darbandi e Mohammad Said Saidi. "Computational Investigation of Graphene Behavior Under Differential Water Pressure and Possible Mass Transfer Influences". In ASME 2016 5th International Conference on Micro/Nanoscale Heat and Mass Transfer. American Society of Mechanical Engineers, 2016. http://dx.doi.org/10.1115/mnhmt2016-6571.
Testo completoAbstract (sommario):
Because of its unique properties, graphene has attracted the attentions of many academic research groups and recently, the industry. One of the promising applications of the graphene is in micro/nano-sensors, e.g. using it as a pressure sensor. To use it in mechanical-based nano-sensors, it is very important to investigate the mechanical behavior of the nano-sized graphene sheet and its sensitivity to the medium changes applied on its faces. In this work, we use the molecular dynamics MD method and simulate the behavior of graphene sheet under differential water pressure influences. In this regard, a square straight monolayer graphene sheet is placed as a separator diaphragm between two different water boxes having different pressure/density magnitudes. The graphene atoms located on four sides around the graphene sheet are fixed during the simulations. At first, the two water boxes are in the same condition, i.e., they are a copy of each other. Next, the density of one of the water boxes is changed abruptly to impose the desired pressure difference. We also investigate the mass transfer through the imposed graphene sheet and its impact on the achieved graphene sheet behavior in this study. To the authors’ knowledge, this is the first study to investigate the graphene behavior in this manner. Indeed, one objective of this work is to find the sensitivity of nanoscale graphene sheet to low and high pressure/density differences by investigating its deflections.
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Wang, Shan, Shanshan Li e Zhenhai Pan. "Numerical Investigation of the Forming and Ordering of Inertially Focused Particle Trains in a Square Microchannel". In ASME-JSME-KSME 2019 8th Joint Fluids Engineering Conference. American Society of Mechanical Engineers, 2019. http://dx.doi.org/10.1115/ajkfluids2019-4814.
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Abstract Inertial focusing of microscale particles has increasingly attracted attentions in various microfluidic applications, such as manipulations of particles/cells, flow cytometry, and highsensitive detection, owing to its passive, robust, and high-throughput nature. While most fundamental studies in literatures have focused on the lateral migration and transverse equilibrium position of single particles in micro-channels with various cross sections, very few of them have dug into the forming and ordering mechanisms of an inertially focused particle train. In this study, the forming inertially focused particle trains are investigated by coupling the lattice Boltzmann method with the immersed boundary method (IB-LBM). The inertial migrations of 6 particles (40 μm in diameter) are simulated in a square microchannel (100 μm in width). The results indicated that the equilibrium axis distance between two neighboring particles is strongly affected by complicated particle-to-particle and particle-to-liquid interactions. Two critical length fractions Lf,c1 and Lf,c2 are observed, which have insignificant effect on balanced distance between two neighboring particles in a particle train.
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Chen, Guanyi, Gang Li, Michel P. Glazer, Chunlei Zhang e J. Andries. "Operation of a Circulating Fluidised Bed Biomass Gasifier". In ASME Turbo Expo 2004: Power for Land, Sea, and Air. ASMEDC, 2004. http://dx.doi.org/10.1115/gt2004-53659.
Testo completoAbstract (sommario):
Energy generation from the use of biomass is gaining an increasing attention. Gasification of biomass at present, is widely accepted as a popular technical route to produce fuel gas for the application in boilers, engine, gas/micro turbine or fuel cell. Up to now, most of researchers have focused their attentions only on fixed-bed gasification and fluidised bed gasification under air-blown conditions. In that case, the producer gas is contaminated by high tar contents and particles which could lead to the corrosion and wear of blades of turbine. Furthermore, both the technologies, particularly fixed bed gasification, are not flexible for using multiple biomass-fuel types and also not feasible economically and environmentally for large scale application up to 10∼50 MWth. An innovative circulating fluidised bed concept has been considered in our laboratory for biomass gasification thereby overcoming these challenges. The concept combines and integrates partial oxidation, fast pyrolysis (with an instantaneous drying), gasification, and tar cracking, as well as a shift reaction, with the purpose of producing a high quality of gas, in terms of low tar level and particulates carried out in the producer gas, and overall emissions reduction associated with the combustion of producer gas. This paper describes our innovative concept and presents some experimental results. The results indicate that the gas yield can be above 1.80Nm3/kg with the calorific value of 4.5–5.0MJ/Nm3, and the fluctuation of the gas yield during the period of operation is 3.3%–3.5% for the temperature of 750–800 °C. In genera, the results achieved support our concept as a promising alternative for the gasifier coupled with micro/gas turbine to generate electricity.
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Li, Xinxin, Zhimin Li, Sun Jin, Jichang Zhang, Zhihua Niu e Jinyu Liu. "Contact Properties Research for Linear Sliding Guide Rail With the Fractal Theory". In ASME 2019 International Mechanical Engineering Congress and Exposition. American Society of Mechanical Engineers, 2019. http://dx.doi.org/10.1115/imece2019-10832.
Testo completoAbstract (sommario):
Abstract High quality products are primarily dependent on the accurate translation motion of each linear sliding guide rail (LSGR) of CNC machine tools in the advanced manufacturing industry. The existing researches about LSGR precision pay much more attentions on the components dimensional variation and deformations, while micro-geometric form errors (such as surface roughness) have been ignored in most previous studies. Therefore, the true contact interface property is so crucial that it will affect macro-mechanical performance, such as friction, wear, assembly relation, tightness, fatigue strength, etc. In order to obtain the contact behaviors of LSGR accurately, a novel finite element model contact analysis is proposed in this paper. Instead of adopting the conventional statistic characterization method, such as Greenwood-Williamson (GW) model, the rough slider surface generated by the fractal function get closer to the real surface topography. In this study, the true contact area, contact pressure, contact stress and deformation are all investigated. Furthermore, the contact properties results of the present model are in a good agreement with other analytical solutions. In conclusion, the proposed finite element model combining with the fractal theory may provide an accurate contact analysis for LSGR. It is also great of guiding significance for the prediction of assembly quality and operation performance in high-precision measurement region as well as other precise engineering applications.