检索结果-内蒙古大学图书馆

IEEE/RSJ International Conference on Intelligent Robots and Systems

作者： G. P. Kontoudis M. V. Liarokapis A. G. Zisimatos C. I. Mavrogiannis K. J. Kyriakopoulos Control Systems Lab School of Mechanical Engineering National Technical University of Athens Athens Greece Dept. of Mech. Eng. and Materials Science Yale University New Haven CT USA Sibley School of Mechanical & Aerospace Engineering Cornell University Ithaca NY USA

In this paper we present an open-source design for the development of low-complexity, anthropomorphic, underactuated robot hands with a selectively lockable differential mechanism. The differential mechanism used is a variation of the whiffletree (or seesaw) mechanism, which introduces a set of locking buttons that can block the motion of each finger. The proposed design is unique since with a single motor and the proposed differential mechanism the user is able to control each finger independently and switch between different grasping postures in an intuitive manner. Anthropomorphism of robot structure and motion is achieved by employing in the design process an index of anthropomorphism. The proposed robot hands can be easily fabricated using low-cost, off-the-shelf materials and rapid prototyping techniques. The efficacy of the proposed design is validated through different experimental paradigms involving grasping of everyday life objects and execution of daily life activities. The proposed hands can be used as affordable prostheses, helping amputees regain their lost dexterity.

关键词： Robots Thumb Grasping Prosthetics Open source software Anthropomorphism Indexes

来源：评论

学校读者我要写书评

暂无评论

The mechanical properties of austenite stainless steel 304 after structural deformation through cold work

引用

AIP Conference Proceedings 2016年第1期1746卷

作者： Naila Mubarok Hamdan Akbar Notonegoro Kemas Ahmad Zaini Thosin Azwar Manaf 1PPS Materials Science FMIPA-Universitas Indonesia Depok 16424 Indonesia 2Mechanical Engineering Dept. FT-Universitas Sultan Ageng TirtayasaCilegon 42435 Indonesia 3Pusat Penelitian Fisika LIPI Serpong Indonesia

The 304 stainless steel (SS) type is widely used in oil and gas operations due to its excellent corrosion resistance. However, the presence of the fine sand particles and H2S gas contained in crude oil could lead the erosion and abrasion in steel. In this study, cold rolled treatments were conducted to the 304 SS in order to increase the wear resistance of the steel. The cold work has resulted in thickness reduction to 20%, 40% and 60% of the original. Various microstructural characterizations were used to analyze the effect of deformation. The hardness characterization showed that the initial hardness value increased from 145 HVC to 395 HVC as the level of deformation increase. Further, the wear resistance increased with the deformation rate from 0% to 40% and subsequently decreased from 40% to 60% deformation rate. Microstructural characterization shows that the boundary change to coincide by 56 µm, 49 µm, 45 µm, and 43 µm width and the grain go to flatten and being folded like needles. The effect of deformation on the grain morphology and structure was also studied by optical metallography and X-Ray Diffraction. It is shown that the deformation by means of a cold rolled process has transformed the austenite structure into martensitic structure.

关键词：

来源：评论

学校读者我要写书评

暂无评论

Fabrication of microcellular metal foams with sphere template electrodeposition

引用

Manufacturing Letters 2014年第4期2卷 118-121页

作者： Jiang, Wei Sundarram, Sriharsha S. Li, Wei Dept. of Mechanical Engineering The University of Texas at Austin AustinTX78712 United States Material Science and Engineering Program The University of Texas at Austin AustinTX78712 United States

Microcellular metal foam (MMF) is a new class of metallic material with many potential applications such as solar energy storage. In this study we present a sphere template electrodeposition process for bulk MMF fabrication. To overcome ion diffusion limitation and uneven metal growth problems we explore the benefit of a pulse reverse electrodeposition technique. An experimental study was conducted on the effect of pulse voltage and frequency. It is shown that metal deposition uniformity can be significantly improved with high pulse frequency and amplitude. This study suggests that bulk MMFs could be fabricated with a microsphere template electrodeposition process. © 2014 Society of Manufacturing Engineers (SME).

关键词： Microspheres

来源：评论

学校读者我要写书评

暂无评论

Influence of intermetallic Fe and Co on crystal structure disorder and magnetic property of Ni50Mn32Al18 Heusler alloy

引用

Journal of Physics: Conference Series 2016年第1期776卷

作者： H. A. Notonegoro B. Kurniawan J. Setiawan D. Nanto A. Manaf PPS Materials Science FMIPA-Universitas Indonesia Depok 16424 Indonesia Mechanical Engineering Dept. FT-Universitas Sultan Ageng Tirtayasa Cilegon 42435 Indonesia Center for Nuclear Fuel Tecnology-Badan Tenaga Nuklir Nasional Tangerang Selatan 15310 Indonesia Dept. of Physics Education UIN Syarif Hidayatullah Jakarta 15412 Indonesia

This works reports a study on structure and magnetic properties influenced by both Fe and Co on Ni50Mn32Al18 Heusler alloy as a candidate of magnetocaloric effect (MCE) materials. The Ni-Fe-Mn-Co-Al sample was prepared by arc melting furnace (AMF) in high purity argon atmosphere. X-ray diffraction investigation and magnetic hysteresis were conducted to characterize the synthesized sample. X-ray diffraction using Cu-Kα pattern shows that both Fe and Co introduce a tungsten type disorder of Ni50Mn32Al18 Heusler alloy which partially replace the site position of Ni and Mn respectively. However, in this tungsten type disorder, it is difficult to distinguish the exact position of each constituent atom. Therefore, we believe it may allow any exchange interaction of each electron possessed the atom. Interestingly, it produced a significant increase in the value of the hysteresis magnetic saturation.

关键词：

来源：评论

学校读者我要写书评

暂无评论

Mechanism of forming joining on backward extrusion forged bonding process

Mechanism of forming joining on backward extrusion forged bo...

引用

6th International Conference on Tribology in Manufacturing Processes and Joining by Plastic Deformation, ICTMP 2014

作者： Yoshida, Yoshinori Ishikawa, Takashi Suganuma, Tomoaki Dept. of Mechanical and Systems Engineering Gifu University Japan Dept. of Materials Science and Engineering Nagoya University Japan Chubu Reikan Co Ltd Japan

ISBN: (纸本)9783038351276

A backward extrusion forged bonding using low carbon steel and pure aluminum is conducted. The bonding strength between the materials is evaluated by a micro tensile test that is cut out at the bonding boundary. The maximum bonding strength is larger than that of the aluminum. In addition, the metallurgical mechanism of the joining of the backward extrusion forged bonding is investigated by means of a scanning transmission electron microscope (STEM). An intermetallic compound (IMC) layer is produced at the boundary with a thickness of about 3 nm. The process is applied for bonding between aluminum-nickel and between aluminum-copper. The bonding strength between the materials was evaluated by using a micro tensile test and the maximum bonding strength is shown. Fractured surfaces of the tensile specimens are observed by scanning electron microscope (SEM) and relationship between bonding strength and position on the boundary is discussed. © (2014) Trans Tech Publications, Switzerland.

关键词： Aluminum

来源：评论

学校读者我要写书评

暂无评论

Simulation of secondary and separated flow in a diffusing S-duct 52

Simulation of secondary and separated flow in a diffusing S-...

引用

52nd AIAA Aerospace sciences Meeting - AIAA science and Technology Forum and Exposition, SciTech 2014

作者： Fiola, Colin Agarwal, Ramesh K. Dept. of Mechanical Engineering and Materials Science Washington University St. Louis MO 63130 United States

ISBN: (数字)9781624102561

ISBN: (纸本)9781624102561

The focus of this paper is on the numerical simulation of compressible flow in a diffusing S-duct inlet;this flow is characterized by secondary flow as well as regions of boundary layer separation. The S-Duct geometry produces streamline curvature and an adverse pressure gradient resulting iu these flow characteristics. Two S-duct geometries are employed in this investigation-one is used iu an experimental study conducted at NASA Glenn Research Center in the early 1990's and the other is a benchmark configuration proposed by AIAA Propulsion Aerodynamics Workshop (PAW) to assess the accuracy and best practices of CFD *** CFD flow solver ANSYS-FLUENT is employed in the investigation of compressible turbulent flow through the S-duct. A second-order accurate, steady, density-based solver is employed in a finite-volume framework. The three-dimensional Reynolds-Averaged Navier-Stokes (RANS) equations are solved on a structured mesh with a number of turbulence models, namely the Spalart - Alimaras (SA), k-Ε, k-ω SST, and Transition SST models, and the results are compared with the available experimental data. The computed results capture the flow field and pressure recovery with acceptable accuracy when compared to the experimental data. The turbulence model giving the best results is identified.

关键词： Turbulence models

来源：评论

学校读者我要写书评

暂无评论

Magnetic hysterysis evolution of Ni-Al alloy with Fe and Mn substitution by vacuum arc melting to produce the room temperature magnetocaloric effect material

引用

AIP Conference Proceedings 2016年第1期1746卷

作者： Hamdan Akbar Notonegoro Budhy Kurniawan Jan Setiawan Azwar Manaf 1PPS Materials Science FMIPA-Universitas Indonesia Depok 16424 Indonesia 2Mechanical Engineering Dept. FT-Universitas Sultan Ageng Tirtayasa Cilegon 42435 Indonesia 3Center for Nuclear Fuel Tecnology-Badan Tenaga Atom Nasional Tangerang Selatan 15310 Indonesia

The development of magnetocaloric effect (MCE) material is done in order to reduce the damage of the ozone layer caused by the chlorofluorocarbons (CFCs) emitted into the air. The research dealing with synthesis of magnetocaloric materials based of Ni-Al Heusler Alloy structure and by varying substitution some atoms of Ni with Fe and Al with Mn on Ni-Al Heusler Alloy structure to become Ni44Fe6Mn32Al18. Vacuum Arc Melting (VAM) equipment is used to form the alloys on vacuum condition and by flowing argon gas atmosphere and then followed by annealing process for 72 hours. X-Ray Diffraction (XRD) reveals that crystallite structure of material is observed. We define that Ni44Fe6 as X2, Mn25 as Y, and Al18Mn7 as Z. Based on the XRD result, we observed that the general formula X2YZ is not changed. The PERMAGRAF measurement revealed that there exists of magnetic hysterysis. The hysterysis show that the magnetic structures of the system undego evolution from diamagnetic to soft ferromagnetic material which all of the compound have the same crystallite structure. This evolution indicated that the change in the composition has led to changes the magnetic composition. Mn is the major element that gives strong magnetic properties to the sample. When Mn partially replaced position of Al, the sample became dominant to be influenced to improve their magnetic properties. In addition, substitution a part of Ni by Fe in the composition reveals a pinning of the domain walls in the sample.

关键词：

来源：评论

学校读者我要写书评

暂无评论

Needs and opportunities for nanotribology in MEMS and NEMS

Needs and opportunities for nanotribology in MEMS and NEMS

引用

2014 Solid-State Sensors, Actuators and Microsystems Workshop, Hilton Head 2014

作者： Carpick, R.W. Wabiszewski, G.E. Streller, F. Dept. of Mechanical Engineering and Applied Mechanics U. Pennsylvania PhiladelphiaPA United States Dept. of Materials Science and Engineering U. Pennsylvania PhiladelphiaPA United States

ISBN: (纸本)9781940470016

Nanoelectromechanical systems (NEMS) switches are a candidate "beyond CMOS" technology, with a key benefit being massively reduced power consumption. However, the reliability of the contact interface is a principal challenge, as the electrically conducting contacting surfaces need to be able to open and close up to a quadrillion times without excessive adhesion, wear, or contamination. Similar failure mechanisms occur in microelectromechanical systems (MEMS). These failure mechanisms are not well understood, and materials that can exhibit the needed performance have not yet been demonstrated. Here we highlight key challenges and opportunities for applying scientific insights from nanotribology to address these reliability challenges. © 2014TRF.

关键词： MEMS

来源：评论

学校读者我要写书评

暂无评论

CFD analysis of open rotor engines using an actuator disk model 52

CFD analysis of open rotor engines using an actuator disk mo...

引用

52nd AIAA Aerospace sciences Meeting - AIAA science and Technology Forum and Exposition, SciTech 2014

作者： Farrar, Bryan Agarwal, Ramesh Washington University in St. Louis Dept. of Mechanical Engineering and Materials Science St Louis MO 63130 United States

ISBN: (数字)9781624102561

ISBN: (纸本)9781624102561

In the world of air transportation today, there is increasing emphasis on 'Environmentally Responsible Aviation' that addresses more energy efficient and environmentally sustainable aircraft with low emissions and noise. Due to its high propulsive efficiency, an Open Rotor gas turbine engine has the potential to significantly minimize the specific fuel consumption and reduce CO2 emissions in a new generation of transport aircraft. In mid-1980's GE invested significant effort in advanced turbo-prop technology (ATP) and un-ducted fan technology (UDF). However, in spite of its potential for 30% savings in fuel consumption over existing turbofan engines with comparable performance, for a variety of technical and business reasons, the advanced turboprop concept never quite got-off the ground. However, with current emphasis on "Green Aviation" NASA and aircraft engine industry (GE, Pratt-Whiney and Rolls-Royce) are investing significant resources in Open Rotor research and development. The goal of this study is to develop a numerical model to study the performance of counter rotating open rotors (CROR). Advanced CFD studies using the unsteady Reynolds - Averaged Navier-Stokes (URANS) equations are quite complex and computationally intensive. Therefore as a first step, we have developed a simplified model based on Froude's actuator disk method to replace the two spinning rotors with two actuator disks on an axisymmetric model. The URANS computations for this model were performed using the CFD solver ANSYS- FLUENT. The results of computations have been compared using the wind tunnel data on F31/A31 CROR from NASA Glenn's Research Facility. It is shown that the simplified actuator disk model can predict results in excellent agreement with the test data for the hub pressure distribution, while maintaining computational simplicity.

关键词： Gas emissions

来源：评论

学校读者我要写书评

暂无评论

Inclusion of a simple dynamic inflow model in the blade element momentum theory for wind turbine application 32

Inclusion of a simple dynamic inflow model in the blade elem...

引用

32nd AIAA Applied Aerodynamics Conference 2014

作者： Chen, Xiaomin Agarwal, Ramesh K. Dept. of Mechanical Engineering and Materials Science Washington University in St. Louis St. Louis MO 63130 United States Dept. of Mechanical Engineering and Materials Science Washington University in St. Louis One Brookings Drive St. Louis MO 63130 United States

ISBN: (数字)9781624102882

ISBN: (纸本)9781624102882

It is well established that the power generated by a Horizontal-Axis Wind Turbine (HAWT) is a function of the number of blades B, the tip speed ratio λr (blade tip speed/wind free-stream velocity) and the lift to drag ratio (CL /CD) of the airfoil sections of the blade. The previous studies have shown that Blade Element Momentum (BEM) theory is capable of evaluating the steady-state performance of wind turbines, in particular it can provide a reasonably good estimate of generated power at a given wind speed. However in more realistic applications, wind turbine operating conditions change from time to time due to variations in wind velocity and the aerodynamic forces change to new steady-state values after the wake settles to a new equilibrium whenever changes in operating conditions occur. The goal of this paper is to modify the quasi-steady BEM theory by including a simple dynamic inflow model to capture the unsteady behavior of wind turbines on a larger time scale. The output power of the wind turbines is calculated using the improved BEM method incorporating the inflow model. The computations are performed for the original NREL Phase II and Phase III turbines and the Risoe turbine all employing the S809 airfoil section for the turbine blades. It is shown by a simple example that the improved BEM theory is capable of evaluating the wind turbine performance in practical situations where operating conditions often vary in time.

关键词： Horizontal axis wind turbine

来源：评论

学校读者我要写书评

暂无评论

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

请选择保存的检索档案：

请选择收藏分类：

通借通还

建议与咨询 留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

请选择保存的检索档案： 新增检索档案 确定 取消

请选择收藏分类： 新增自定义分类 确定 取消

通借通还

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

请选择保存的检索档案：

请选择收藏分类：