bluuebunny/crossref_metadata_2025 huggingface dataset:
New Poiseuille-Couette Flow of Variable Viscosity Fluid in Microscale Gap Between Parallel Plates
Authors: Zhou Cheng , Yang Huayong
Published: May 2009

The Poiseuille-Couette flow in microscale gap between parallel plates, driven by the simultaneous pressure gradient and the movement of the upper plate in the tangential direction, has been studied numerically with the finite volume method. The heights of the studied gaps are 40μm, 70μm and 100μm. The lengths of the gaps are fixed at 25mm. The flow regime is laminar with the pressure difference between the inlet and the outlet varying from 1 MPa to 10 MPa and the tangential velocity of the moving wall varying from 0 to 20 m/s. Due to the effect of viscous dissipation and temperature dependent viscosity, the Poiseuille-Couette flow deviates from the classical flow. The differences of temperature distribution, Poiseuille number, velocity profiles, flow rate and plate friction are discussed in detail.
Study of the Tensile Strength of Nanostructured Copper Obtained by Electrodeposition and SMAT
Authors: Chan H. L. , Lu J.
Published: May 2009

The tensile strength of nanostructured Cu obtained by electrodeposition and Surface Mechanical Attrition Treatment (SMAT) was studied. Cu after electrodeposition had been first studied. Electrodeposited Cu had the well-known reduction on the grain size and as well as the improvement on the strength compared with the bulk hard copper. After SMAT, although the ductility had dropped, the yield strength is further enhanced up to 50% (350MPa) to obtain a stronger material. Since the parameters of the electrodeposition affects the properties of the materials obtained, rooms for improvement could be expected, for example, increasing the duration of the electrodeposition may increase the ductility significantly, in the later stage of this study, experimental results proved this saying. The present study demonstrates the potential process for developing a novel surface nanostructured material with electrodeposited Copper with SMAT for engineering applications.
Development of Quantum Dot Mediated Cell Image Deformetry for Microscale Tissue Deformation Measurement
Authors: Jung Jun K. , Teo Ka Yaw , Dutton J. Craig , Han Bumsoo
Published: May 2009

Since biological tissues are composed of cells, extracellular matrix, and interstitial fluid, freezing of biological tissues induces complex cell-fluid-matrix interaction. Quantitative understanding of this cell-fluid-matrix interaction is crucial to the design and optimization of a wide variety of cryomedicine applications. However, quantitative measurement of the interaction is extremely challenging due to the lack of reliable non-invasive measurement techniques during freezing and thawing. In the present study, a new measurement technique was developed to dynamically measure microscale tissue deformation during freezing/thawing and its feasibility was demonstrated. In this method, which is named “Cell Image Deformetry” (CID), engineered tissues with pre-labeled cells with quantum dots are imaged under a fluorescence microscope. Then, the tissue deformation is evaluated by cross-correlating cell locations between sequential microscopic images with known time intervals based on the particle image velocimetry (PIV) data processing technique.
Experimental Study of Drawing Process With Servo Press
Authors: Tso Pei-Lum , Liu Hsin-Kai , Li Cheng-Ho
Published: May 2009

Servo presses providing flexible ram motions are extensively developed nowadays; the merit of such presses is the capability of generating versatile punch motions to fulfill the stamping. This paper studies a cup-shaped drawing process using a servo press. The aim of this research is to study the effect of the forming speed on preventing the cracks and wrinkles in drawing. A finite element method (FEM) software package—ABAQUS®, is utilized to predict the distribution of displacement stress, strain of the work material in drawing. Crack (related to thinning behavior) and wrinkle are two indices of the drawing failure criteria in simulation. An optimal forming speed could be estimated by simulation. The optimal forming speed would cause the maximum limit drawing ratio which is beneficial to prevent drawing failure. The analytical results were verified experimentally. The results show that the predicted drawing speed was consistent with the real experiment and simulation.
MCAD-ECAD Integration: Overview and Future Research Perspectives
Authors: Chen Kenway , Schaefer Dirk
Published: May 2009

The domain of Electrical Computer-Aided Design and Engineering (ECAD/ECAE) has been subject to major and rapid change over the past couple of years. Electrical Engineering Computer-Aided Design (CAD) tools developed in the early to mid-1990s no longer meet future requirements. Consequently, a new generation of Electrical Engineering CAD systems has been under development for about a decade now. An overview of advances in this field is presented in the introductory part of this paper. This overview also sets the context and provides background information for the main topic, MCAD-ECAD-integration, to be addressed in the remainder of this paper. Many complex engineered systems encompass mechanical as well as electrical engineering components. Unfortunately, contemporary CAE environments do not provide a sufficient degree of integration in order to allow for multi-disciplinary product modeling and bi-directional information flow (i.e. automated design modifications on either side) between mechanical and electrical CAD domains. Overcoming this barrier of systems integration would release a tremendous efficiency potential with regard to the efficient development of multidisciplinary product platforms and configurations. An overview of the state-of-the-art in MCAD-ECAD integration is presented. In addition, associated research questions are postulated and potential future research perspectives discussed.
Modeling for the Development and Evaluation of Strategies for Controlling Flow Instabilities in Transonic Compressors
Authors: Chi John N.
Published: May 2009

A gas turbine engine consists of three primary components: a compressor, a combustion chamber, and a turbine. The operating range, performance, and reliability of gas turbine engines are limited by aerodynamic instabilities that occur in the compressor at low mass flow rates. Two of such compressor instabilities are rotating stall and surge. The stabilization of compression systems by means of active control has been demonstrated on several research compressors using different actuators such as inlet guide vanes, bleed valves, and air injection to manipulate the compressor flow field. This paper presents validated models of the steady and unsteady behaviors of air injection in high speed axial flow compressors that can be used for feasibility studies and control algorithm development. The steady air injection model consists of a control volume analysis coupled with wind tunnel measurements to characterize the changes in flow profiles entering the compressor and a streamline curvature analysis to model the response of the compressor blade rows to the different inlet span-wise profiles generated by the jet actuator. The steady air injection model was validated with experimentally measured span-wise profiles and compressor speed-lines, and then used to study the effect of hot air injection on the performance of a transonic compressor. The results show that injecting hot air into a transonic compressor has a potential increase in the operating range (i.e., decrease in the stalling mass flow rate) and a decrease in the total pressure rise across the transonic compressor. A modified theoretical stall inception model for high speed machines with air injection actuation is also presented. The compressible rotating stall inception model is a two-dimensional linearized stability model and pre-stall dynamics measurements from a single stage transonic compressor were used to validate the model. The compressible rotating stall inception model is an important tool that can be used for studying the effects of compressor design parameters on stability during compressor redesign, and for designing and evaluating feedback controllers.
Design, Analysis and Fabrication of Microflexural NOT Gate
Authors: Modi Abhishek , Gandhi Prasanna S. , Shah Himani , Singh Shiv Govind
Published: May 2009

Binary logic devices constructed using moving mechanical components at microscale can be useful in harsh working environments where their electronic counterparts would fail. This paper demonstrates a novel design, extensive analysis, and development method of a micromechanical NOT gate and analyzes important issues in further development of mechanical logic circuits. The proposed NOT gate uses parallelogram flexures and flexure beam hinges to realize the logic without effects of friction. Extensive finite element (FE) analysis, carried out using ANSYS, enables us to arrive at the final design dimensions. We introduce a new term “Energy Transmission Ratio (ETR)” specific to flexure mechanism-based transmission systems and further FE analysis brings out interesting property that ETR has an optimal value for given flexure geometry. This result can be useful while connecting several logic gates to develop mechanical logic circuits. A graphical procedure for analysis of such connections is outlined based on our FE results. Finally, the proposed NOT gate is fabricated with SU-8 and demonstrated working successfully.
Numerical Analysis of Hydrodynamics and Heat Transfer of a Free Surface Circular Jet Impinging Onto a Substrate
Authors: Fujimoto Hitoshi , Dejima Shinya , Tong Albert Y. , Hama Takayuki , Takuda Hirohiko
Published: May 2009

The present paper is concerned with three-dimensional numerical simulations of hydrodynamics and convective heat transfer of a free surface liquid jet impinging onto a hot substrate. The Navier-Stokes equations for unsteady incompressible viscous fluids are used and are solved numerically by a finite difference method. The numerical model is validated by comparing the results with experiments conducted by other researchers under the conditions of normal impingement. Oblique impingement of liquid jets onto a substrate is treated. It is found that the stagnation point does not coincide with the geometric jet center on the solid surface. The deviation increases with decreasing impact angles, i.e. increasing degree of obliqueness. The peak of local Nusselt number is also shifted in accordance with the flow profile. The velocity and temperature distributions are examined in detail to better understand the physics of the oblique impingement phenomena.
Upstream Vortex Effects on Turbine Blade Platform Film Cooling With Typical Stator-Rotor Purge Flow
Authors: Gao Zhihong , Narzary Diganta , Mhetras Shantanu , Han Je-Chin
Published: May 2009

Detailed film cooling effectiveness distributions were experimentally obtained on a turbine blade platform within a five-blade linear cascade. A typical labyrinth-like seal was placed upstream of the cascade blades to simulate purge flow from a stator-rotor gap. Delta wings were periodically placed upstream of the blades to model the effect of the passage vortex generated in the vane passage on the downstream blade platform film cooling effectiveness. Typical vane passage vortex was simulated by two delta wings with height of 10% and 20% of the blade span, respectively. The strength of vane passage vortex was also modeled by varying the attack angle of mainstream to the delta wing. The film cooling effectiveness was measured with the delta wings placed at four phase locations, to investigate the effect of the passing vanes. The detailed film cooling effectiveness distributions on the platform were obtained using pressure sensitive paint (PSP) technique. The coolant mass flow rate varied from 0.25% to 1.0% of the mainstream flow. The freestream Reynolds number, based on the axial chord length and the exit velocity, was 750,000. The Mach numbers at the inlet and the exit were 0.27 and 0.44, respectively. The vortex generated by the delta wings had a profound impact on the platform film cooling effectiveness. The upstream vortex created more turbulent mixing within the blade passage and resulted in reduced film cooling effectiveness on the blade platform.
Study of Characteristic of Evacuated Flat Plate Type Solar Collector With Flow Boiling
Authors: Taniguchi Masahiro , Hirasawa Shigeki , Nakauchi Shunsaku , Tanaka Tadayoshi
Published: May 2009

An evacuated solar collector system with flow boiling in tube has high collector efficiency of solar energy. In this paper, we present experimental and simulation results for characterizing an evacuated flat plate solar collector. By comparing the experiment results with six boiling heat transfer correlation equations, we found that Sani’s correlation is closest to our experimental results. Subsequently, this paper reports on how various factors impact collector efficiency. Collector efficiency decreases with decreasing flow rate of the working fluid, with decreasing solar irradiation, with reduction of thickness and thermal conductivity of the heat collector plate. Collector efficiency increases with decreasing saturation temperature of the working fluid, with decreasing vacuum pressure in the collector, with small bending angle of the heat collector tube. Collector efficiency does not change with change of inside diameter of the heat collection tube, and with change of inlet subcooling temperature of the working fluid.
A Thermal Model for Ultrasonic Welding of Thermoplastics
Authors: Ling S.-F. , Li X. , Sun Z.
Published: May 2009

Ultrasonic welding is one of the most popular techniques for joining thermoplastics and plays an important role in MEMS applications such as fabrication and packaging of MEMS devices. In this paper, an attempt was made to further understand the heating mechanism during ultrasonic welding. Firstly, the equation governing heat generation was derived assuming adiabatic heating. A thermal equivalent circuit model was also developed to describe the heat transfer process from the joint interface into the surroundings, and the governing equation of temperature distribution in the welding sample was deduced. Finite element method was then engaged to solve these equations to reveal the transient heating behaviour. Lastly, temperatures of the joint interface and the point adjacent to the joint were measured. The temperatures of the point adjacent to the joint calculated from finite element model are matched well with the experimental results. Based on the correlation, the temperature distributions of welding samples can be derived from the finite element model. Since the new developed model can be used to obtain the dynamic temperature distributions of welding samples during ultrasonic welding, the model provides an effective way for detailed understanding of the thermal behaviours and monitoring of the ultrasonic welding process.
3-D Lithography by CCFL Exposure
Authors: Yuan Zong-Ting , Lee Cheng-Chang , Wang Horng-Jou , Chang Heng-Chung , Chen Huang-Kun , Shing Tai-Kang
Published: May 2009

A novel means for 3-D microfabrication is proposed. First, a process for generating metal patterns on the outer surface of a CCFL (Cold Cathode Fluorescent Lamp) was developed. The CCFL with the integrated mask was then used as an exposure source for subsequent lithography process to achieve the pattern transfer on the inner surface of a Cu tube. After wet etch, various grooves were successfully fabricated onto the inner surface of the Cu tube with a 2.47mm inner diameter. By the proposed method, the minimum achievable line-width could be less than 20μm. Compared with traditional manufacturing methods, the proposed approach could improve the machining precision and roughness, reduce the manufacturing difficulties, and lower the manufacturing cost substantially.
Stability of the Controlled Inverted Pendulum With Vertical Oscillations
Authors: Nakagawa Chihiro , Nakano Kimihiko , Suda Yoshihiro , Hayashi Ryuzo
Published: May 2009

These days, inverted pendulum robots, like a two-wheeled robot or vehicle, are seen as a form of dynamically stabilized vehicle. Stability characteristics and moving performances of these vehicles have been studied through many examinations and demonstrations. Considering their practical usage, however, these vehicles travel on rough roads, as well as the flat surface in a laboratory. Therefore it is important to investigate the stability of the dynamically stabilized vehicle under vertical vibration. In this study, the authors investigate the responses of the inverted pendulum, which is stabilized by an optimal controller, to vertical vibrations. With theoretical analysis, numerical simulations and experiments using a large scale vibration exciter, stability to vertical vibration is examined. The results show the system dynamics are governed by the Mathieu equation, thus the amplitude ratio reaches its peak when the frequency of the forced vibration is twice the natural frequency of the controlled inverted pendulum system.
Flow Simulation and Optimization of a Left Ventricular Assist Device
Authors: Sorguven Esra , Ciblak Namik , Okyar A. Fethi , Akgun Mehmet A. , Egrican A. Nilufer , Safak K. Koray , Ahn Hojin , Lazoglu I˙smail , Kucukaksu Suha
Published: May 2009

Artificial assist devices offer a promising treatment option for patients with congestive heart failure, especially when the patient is not eligible for heart transplantation. In order to develop a left ventricular assist device an interdisciplinary research, involving engineering and medical research teams, is conducted. The left ventricular assist device investigated in this study is the MicroMed DeBakey VAD [1], an axial blood pump that provides flow from the left ventricle to the aorta. The geometry of this baseline design is generated via parametric modeling. An optimization surface around the baseline design is formed by using the design of experiments method. Accordingly, eighty parameter sets and the corresponding CAD models are created. Flow through these pumps is simulated at the operation point. Flow data are evaluated to predict the pump performance, blood damage and bearing friction. An axial pump, closer to the optimum, is found that provides 8635 Pa pressure increase at a flow rate of 6 l/min and a rotational speed of 10000 rpm. Pressure head of the selected pump is 18% higher and blood damage is 4% less than the baseline design.
Influence of Flow Maldistribution on the Pressure Drop and Water Condensation in a 100 kW PEM Fuel Cell Stack
Authors: Ito Takamasa , Yuan Jinliang , Sunde´n Bengt
Published: May 2009

The Proton Exchange Membrane (PEM) fuel cell has been investigated for a long time because it has a high power density, low emission, wide choice of fuel sources, etc. However, the performance of a stack of PEM cells degrades with respect to that of a single cell. This is mainly due to the introduction of the manifold in which supplies the reactants to individual cells. The manifold can induce an additional pressure drop and a flow maldistribution. Therefore, it is critical to consider the interaction between the design of the manifold and the flow maldistribution. In this study, the sensitivity of the friction factor in the individual cells to the flow maldistribution and the interaction between the flow maldistribution and water condensation are discussed. As a result, it is found that the friction factors in the individual cells strongly influences the flow maldistribution especially when the flow in the unit cell is changed from laminar flow to turbulent. Large flow maldistributions induce the large pressure drops. As a result, water condensation can be little. However, it also induces a degradation in stack performance. A bipolar plate with a low number of flow channels can improve the flow maldistribution and water condensation in the unit cell although at the expense of a large pressure drop.
Development of Off-Line-Programming System for Automatic Propeller Grinding Robot System
Authors: Jung C. W. , Lee Y. S. , Kim J. G. , Jeon D. J. , Kim J. O. , Park J. W.
Published: May 2009

An off-line programming system (OLP) for the grinding robot has been developed and applied to manufacturing a large scale commercial ship’s propellers. It is necessary to develop the off-line programming system which generates robot motion programs for sensing and grinding the curved surfaces of propeller. The robot performs a sensing process with a laser displacement sensor. Three dimensional surfaces of propeller are generated by the off-line programming system after sensing. The grinding program for the robot is generated from the measured surface in the off-line programming system. After then, the robot performs grinding process automatically.
Thermal Analysis and Modeling of LED Arrays for Automotive Headlamp
Authors: Jang Sun Ho , Shin Moo Whan
Published: May 2009

In this paper we report the thermal performance of LED head lamp module and the cooling system. The precise fluid field modeling and heat transfer analysis using a CFD (Computational Fluid Dynamics) were performed according to the practical working conditions for the headlamp. The junction temperatures of LEDs were found to decrease by using the air cooling system and thus improved the heat dissipating capability of the LED array. The junction temperature of the LED array was decreased from 70.6 °C to 30.25 °C when the circulating speed of the air increased from 0 km/h to 120 km/h. And the temperature decrease of 2∼4 °C was obtained by using fins. By the thermal analysis, a new thermal design was obtained for the cooling system of LED arrays for the headlamps. Thus the reliability of the headlamp with LED arrays can be improved with a good cooling system.
Flow Characteristics at Low Quality for Horizontal Gas-Liquid Two-Phase Flow Through Porous Media
Authors: Takatsu Yasuyuki , Masuoka Takashi , Takehara Takeru
Published: May 2009

As the geometric complexity of porous media brings about technical diffculties of the measurement and the visualization of the microscopic flow field, only few attempts have ever been made at the experimental examination of the two-phase flow through porous media. Therefore, we adopt a bank of tubes in a narrow gap as a porous model, and perform the visualization to examine the microscopic flow field for the horizontal two-phase flow through porous media in detail. The solid matrix in porous media plays an important role in the formation of the two-phase flow pattern. The solid matrix forces larger bubble than its representative length to be split, and the liquid bridge due to the capillary effect prevents the gas-phase merging together. Furthermore, the bubbles are trapped in the wide space surrounded with the solid matrices, where the compound bubble further absorbs smaller bubbles.
Experimental Investigation of the Parameters Influencing Refrigerant Migration in a Refrigeration System
Authors: Kocaturk Serdar , Guldali Yalcin , Egrican A. Nilufer
Published: May 2009

Refrigerant migration, which is characterized by the pressure equalization between condenser and evaporator during compressor off period, is one of the most effective cycling losses phenomena with the cause of 5–15% increasing rates in the energy consumption of a refrigeration system. In this study, an experimental facility was set up to investigate the parameters influencing refrigerant migration. A freezer cabinet with wire&tube evaporator and R600a and R134a reciprocating compressors were used. For the detailed control of various condensing parameters (condensing temperature, pressure, condensing rate in the condenser) a double-tube water-cooled condenser was designed. The condenser was constructed to allow the application of various lengths. Temperature and pressure values on various points of the system, refrigerant mass-flow rate, compressor power and consumed energy values were measured simultaneously. Condensing pressure and condensing rate in the condenser, condenser length, cycling frequency, refrigerant type used in the system, and ambient temperature were investigated as parameters influencing refrigerant migration. Refrigerant migration during the off period was blocked with a solenoid valve that is located before the inlet of the expansion device, and energy consumptions and COP values were mainly compared for the opened-valve and closed-valve conditions for each controlled experimental parameter.
A Study on Evaluation Technique for the Fatigue Life Scatter of Lead-Free Solder Joints
Authors: Miyauchi Hiroki , Yu Qiang , Shibutani Tadahiro , Shiratori Masaki
Published: May 2009

The electronic device equipments using a lot of semiconductors are widespread to all industrial fields. Solder joints are used to mount the electronic chips, such as ceramic resistors and capacitors, on the printed-circuit boards in almost all electronic devices. However, since in many cases the thermal expansion coefficients of electronic parts and PCBs have mismatch, cyclic thermal stress and strain causes solder fatigue. Especially in the power electronic module and car electric module, the evaluation of thermal fatigue life for the chip components is important. It is understood that the fatigue lives of some electronic devices show large scatter in the thermal cycle test, even if their design is the same. The dispersion of main design factors of solder joints is thought as one of these reasons. Moreover, the influence of the dispersion grows when the lead-free solder materials are used in the devices. Therefore, it cannot be bypassed as the main issue for the reliability evaluation in the solder joints. In this study, how the dispersion of design factors influences the fatigue life in lead-free solder joint was investigated by the analytical approach. At first, sensitivity analyses were carried out to study the main effect of the dispersion of each factor on solder joints. And then, the interacting effects between the factors on the reliability were studied by considering the structural asymmetry due to the unbalanced solder joints. FEM analyses were carried out, and the fatigue life in solder joints was calculated from the inelastic strain range. As a result, practical evaluating approach for the fatigue life scatter of solder joints was proposed.
Influence of Reinforcements on the Electrical Resistivity of Novel Sn-Ag-Cu Composite Solder
Authors: Nai S. M. L. , Wei J. , Gupta M.
Published: May 2009

In the present study, 2 different composite solder systems were successfully synthesized using powder metallurgy route consisting of: blending, compaction, sintering and extrusion. The Sn-Ag-Cu based composite solders were reinforced with namely, titanium diboride (TiB2) particulates and multi-walled carbon nanotubes (MWCNTs). The extruded materials were then characterized for their electrical resistivity values using the four-point probe setup from Jandel. The electrical resistivity results showed no degradation of electrical performance of the composite solders, except at high volume percentages of TiB2 addition. This signified that with judicious selection of the reinforcement type and the amount of reinforcement addition, these advanced interconnect materials will benefit industries like the microelectronics flip chip assembly and packaging, MEMS systems and NEMS systems.
Two Dimensional Monte Carlo Simulations of Aggregation Phenomena in Ferromagnetic Colloidal Dispersions Composed of Rod-Like Hematite Particles
Authors: Katayama Yuta , Hayasaka Ryo , Satoh Akira
Published: May 2009

We have investigated aggregation phenomena of ferromagnetic colloidal dispersions composed of rod-like hematite particles which have a magnetic moment normal to the particle axis, by means of the cluster-moving Monte Carlo method. In concrete, we have treated a two-dimensional dispersion in order to clarify the influences of the particle aspect ratio, magnetic interactions between particles, and the magnetic field strength on particle aggregations. Internal structures of particle aggregates have been discussed quantitatively in terms of radial distribution, pair correlation, orientational pair correlation functions, and number distributions of clusters. The results obtained here are summarized as follows. Rod-like particles tend to aggregate to form raft-like clusters more significantly along the magnetic moment direction as magnetic particle-particle interactions increase. However, such raft-like clusters do not aggregate further to form thicker clusters, which is in significantly contrast to dispersions of spherical or rod-like particles with a magnetic moment along the particle axis.
On the Optimisation Into Wire Electro-Discharge Machining of Al/Al2O3P Composites
Authors: Patil N. G. , Brahmankar P. K. , Navale L. G.
Published: May 2009

Non-traditional process like wire electro-discharge machining (WEDM) is found to show a promise for machining metal matrix composites (MMCs). However, the machining information for the difficult-to-machine particle-reinforced material is inadequate. This paper is focused on experimental investigation to examine the effect of electrical as well as nonelectrical machining parameters on performance in wire electro-discharge machining of metal matrix composites (Al/Al2O3p). Taguchi orthogonal array was used to study the effect of combination of reinforcement, current, pulse on-time, off-time, servo reference voltage, maximum feed speed, wire speed, flushing pressure and wire tension on kerf width and cutting speed. Reinforcement percentage, current, on-time was found to have significant effect on cutting rate and kerf width. The optimum machining parameter combinations were obtained for cutting speed and kerf width separately.
Combination of Virtual and Physical Objects in User-Centered Design of a Mobile Work Machine Cabin
Authors: Ellman A. , Laitinen J. , Tiainen T.
Published: May 2009

User-centred design methods improve the understanding of user work practices and enable construction of customized and user-friendly products. Applying these methods is, however, challenging since the users must to be able to test prototypes which is too time consuming and expensive with real prototypes. This is particularly true in the case of a mobile work machine cabin because the cabin forms an integral part of the machine so that elements need to be prototyped. The main properties of the cabin are the drivers’ visibility, functionality, ergonomics and safety. Virtual environment (VE) offers an effective way to realize prototyping and provides a means to study the drivers’ visual field from the cabin. Today’s design work is already performed using 3D CAD software. Introducing such models in VE is, however, not without its obstacles, since no native CAD format is supported in VE. Employing a general-purpose 3D graphics format usually destroys the model structure and also visualization parameters such as textures and lighting. When the aim is to have users test the functionality of the cabin, the VE model is unsatisfactory because certain physical parts are also required. First the bench is needed to ensure natural posture of the test driver. Second, the steering wheel and pedals are the objects with which the driver most typically interacts. Third, a set of control panels, including gauges and switches, are also often interacted by the driver. This study presents a setup for virtual testing of a mobile work machine cabin as a resource for user-centred design. The study focuses on the importance of physical objects in making the test situation realistic for hands-on professionals. The prototypes are tested by cabin design professionals experienced the use of CAD tools and real prototypes. The aim is to obtain designers’ evaluations and interpretations of different combinations of virtual and physical objects in prototypes. To achieve this a procedure for user-centred design of mobile work machine cabins is presented. More generally, the study discusses the participation of users in the design process employing VE as a design tool.
Characteristics of Fluid Flow Between Single Rigid Body and Wall of Small-Diameter Tube
Authors: Ishii Daichi , Aratake Kohei , Otsuka Tatsuya , Yoshizawa Masatsugu
Published: May 2009

A multibody system that moves with fluid inside a small-diameter tube is applied to some parts of industry such as a PIG and it is also expected to be developed for future engineering applications. As a first step to considering a multibody system, this study focused on elucidating the flow characteristics around a single rigid body and understanding the effect of a bypass hole. The model considered has been a single rigid body moving at a constant velocity in a narrow tube. Assuming that the flow is steady axisymmetric laminar flow, the fluid flow around the body has been experimentally observed and numerically analyzed. A Rankine’s combined vortex was observed around the body and it was also observed that a layer of fluid near the top wall has characteristics of the boundary layer. Furthermore, a minimum allowable thickness of a bypass hole to cause the successful front-drive effect was obtained.
A Robot System for the Control of Fabric Tension for Inspection
Authors: Fung E. H. K. , Yuen C. W. M. , Hau L. C. , Wong W. K. , Chan L. K.
Published: May 2009

This paper describes the performance of a stepper-motor-based robot system that exerts a prescribe tension on fabrics to facilitate inspection process. In fact, inspection is an important part of quality control in the textile and clothing industry. It is a useful tool to safeguard the quality and ensure that the product can meet the customer expectation and the relevant stipulated standard. Obviously, before the automated inspection process, it is necessary to expand the fabrics being tested to have certain tension. Due to the nonlinear nature of fabric stiffness, it is essential that an adaptive force feedback control be employed to regulate the applied tension. A pair of symmetrical two-link mechanisms with a revolute joint, driven by a stepper motor, in conjunction with an adaptive controller, constitutes the robot system proposed in the present work. The two mechanisms are responsible for stretching the fabrics to be inspected, while the controller regulates the stretching force to the desired value by sensing the reaction force exerted on the links by the fabrics. In order to update the controller parameters so as to account for the nonlinear change of the fabric stiffness, a Model-Reference Adaptive System (MRAS) based on the augmented error is designed. The performance of MRAS is compared with a Proportional-plus-Integral (PI) control. A short-sleeved T-shirt made of knitted fabric is considered for the demonstration of the system. Besides, a prescribed value of tension is set to the system. Numerical simulations are conducted to illustrate the feasibility and performance of the proposed system. Successful outcomes of the present work establish a foundation for the real implementation of the hanger.
Application of In-Channel Micro Chemical Plant to the Production of Functional Microcapsules
Authors: Cha J. M. , Won D. G. , Jeong E. H. , Arakawa T. , Shoji S. , Kim K. C. , Boo J. S. , Go J. S.
Published: May 2009

Polymeric microcapsules can be fabricated by using kernel process called “micro chemical plant system”. The size of microcapsules is more uniform than those made in the conventional pathways. Spherical microcapsules are fabricated through the innovative conjunction of the well-defined amphiphilic block copolymer and stable microfluidic procedure. Crossed microchannel chemical plant are fabricated by using double deep reactive ion etch (DRIE) on 400 μm-thick silicon wafer. The width and depth of this are 100 μm, respectively. PS-b-PMMA copolymer is synthesized by atomic transfer radical polymerization (ATRP) and molecular weight and poly dispersity index (PDI) is 9837 g/mol and 1.08, respectively. With the introduction of two immiscible fluids into the microchannel, droplet flows are visualized by using a high speed CCD camera. The microcapsule was formed due to supramolecular self-assembly of copolymer in the droplet. The characteristics of the produced microcapsules were measured by SEM. A new microfilter was also introduced to separate microcapsule from the suspension fluid.
Distribution of WSS on the Internal Carotid Artery With an Aneurysm: A CFD Sensitivity Study
Authors: Baek Hyoungsu , Jayaraman Mahesh V. , Karniadakis George Em
Published: May 2009

Intracranial blood flow simulations for studying brain aneurysms are based on many assumptions including the Womersley profile for the inlet boundary condition. Moreover, computational domains seem to be more or less arbitrarily chosen. Previous studies have shown that long inlet vessels lead to more realistic flow just upstream of the aneurysm. In order to guide our studies of cerebral aneurysms, using the high-order spectral/hp element method, we systematically investigated the geometric sensitivity of wall shear stress (WSS) on aneurysms; specifically, the effect of parent vessel geometry on the WSS in aneurysms was considered. Using datasets of two patients with different type of aneurysms, five different geometric models were generated. With the aneurysm geometries fixed, the length or turning angles of inlet parent vessel were varied one at a time. This study demonstrates that the turning angle of upstream blood vessel, the type of aneurysm, and its location with respect to the parent vessel affect the distribution of WSS in the aneurysm. In the fusiform aneurysm with sharp turns, the inlet length makes a substantial difference on impinging location, magnitude, and direction of WSS. On the other hand, the saccular type aneurysm with a smoother parent vessel does not show any significant change. Therefore, the computational domain should be determined based on the geometry of parent vessels and the type of aneurysm.
Effects of Acceleration Amplitude and Frequency of Mechanical Vibration on Osteoblast-Like Cells
Authors: Shikata Tetsuo , Shiraishi Toshihiko , Tanaka Kumiko , Morishita Shin , Takeuchi Ryohei
Published: May 2009

Bone formation is subject in vivo to mechanical stimulation. Although many researches for bone cells of osteoblastic lineage sensing and responding to mechanical stimulation have been reported mainly in the biochemical field, effects of mechanical stimulation on bone cells are not well understood. In this study, in order to clarify effects of acceleration amplitude and frequency of mechanical stimulation on MC3T3-E1, which is an osteoblast-like cell line derived from mouse calvaria, in the sense of mechanical vibrations, their cell proliferation, cell morphology, bone matrix generation and gene expression of alkaline phosphatase (ALP) were investigated when sinusoidal inertia force was applied to the cells. After the cells were cultured in culture plates in a CO2 incubator for one day and adhered on the cultured plane, vibrating groups of the culture plates were set on an aluminum plate attached to a exciter and cultured under sinusoidal excitation in another incubator separated from non-vibrating groups of the culture plates. Acceleration amplitude and frequency were set to several kinds of conditions. The time evolution of cell density was obtained by counting the number of cells with a hemocytometer. The cell morphology was observed with a phase contrast microscope. Calcium salts generated by the cells were observed by being stained with alizarin red S solution and their images were captured with a CCD camera. The vibrating groups for the cell proliferation and the calcium salts staining were sinusoidally excited for 24 hours a day during 28-day cultivation. Gene expression of ALP was measured by a real-time reverse transcription polymerase chain reaction (real-time RT-PCR) method. After the vibrating groups for the PCR were excited for 7 days, the total RNAs were extracted. After reverse transcription, real-time RT-PCR was performed. Gene expression for ALP and a housekeeping gene were determined simultaneously for each sample. ALP gene level in each sample was normalized to the measured housekeeping gene level. The results to be obtained are as follows. In the range from 12.5 to 200 Hz, saturation cell density for the cell proliferation shows tendency of increase as frequency decreases and ALP gene expression shows a peak to frequency at 50 Hz. Among 0, 0.25 and 0.5 G, saturation cell density and ALP gene expression show tendency of increase as acceleration amplitude increases.
Multiscale Constitutive Model Development and Finite Element Implementation for Magnetostrictive Materials
Authors: Oates William S.
Published: May 2009

A multiscale constitutive model is developed and applied to magnetostrictive materials to predict multi-axial ferromagnetic switching. The modeling framework is an extension of a one-dimensional homogenized energy model that employs a stochastic distribution of localized magnetic moments. Here, the model is extended to multi-axial ferromagnetic switching in a polycrystalline ferromagnetic material. A mean-field approximation is adopted to quantify ferromagnetic switching from multi-axial magnetic field loading at the single crystal length scale. Polycrystalline ferromagnetic behavior is modeled by homogenizing stochastic distributions of underlying microscopic fields associated with material inhomogeneities at the grain length scale. Approximations of the stochastic distributions are made to improve computational efficiency for finite element implementation. The constitutive model is numerically validated and implemented in the commercial finite element software, COMSOL.
Robust Adaptive Control Design for Vehicle Lane Keeping Assist
Authors: Chen Liang-Kuang , Lin Liang-Chi
Published: May 2009

A variable structure model reference adaptive control that can compensate parametric variation for systems with input delay is applied to the design of vehicle steering assist. The controller includes a predictor to counteract the effect of the delay, and can enhance the robustness due to the variable structure design, and is therefore an attractive choice to compensate driver behavior variation. Preliminary simulation study indicates that this design successfully compensate the system to track the reference model. Driving simulator experiments are currently in progress to verify the design with human drivers.
Improved Loss Modeling of Hydrostatic Units: Requirement for Precise Simulation of Mobile Working Machine Drivelines
Authors: Kohma¨scher Torsten , Rahmfeld Robert , Murrenhoff Hubertus , Skirde Eckhard
Published: May 2009

The aim of this paper is to analyze different loss modeling methods for hydrostatic pumps and motors as an input for dynamic system simulation. Using dynamic simulation in an early design phase allows for optimization of driveline, driveline control and working hydraulic within several operating conditions. Using precise loss modeling methods enables prediction of energy consumption and energy losses over various duty cycles. Rising energy costs, enhanced government guidelines and increased environmental awareness require more efficient drive concepts especially in mobile working machines. Because of the complex machine structure with numerous hydraulic power consumers, like driveline, working, steering and braking hydraulic, dynamic system simulation is a need in the early design phase. This paper focuses on partial and full hydrostatic drivelines of mobile working machines which operate mostly on basis of a closed circuit hydrostatic transmission. Hydrostatic power lines connect pump and motor directly without additional losses because of valves or system characteristics. Therefore losses in the hydrostatic units have major relevance for the loss behavior of the hydrostatic transmission. The use of precise loss models is essential for analyzing hydrostatic transmission by means of dynamic system simulation. In the scope of this paper, one physical-empiric and four mathematical loss modeling methods are introduced, investigated and compared. Finally, the most promising modeling method is used for the simulation of a state of the art hydrostatic transmission.
Fuzzy Expert Systems for the Diagnosis of Component and Sensor Faults in Complex Energy Systems
Authors: Toffolo Andrea
Published: May 2009

Locating the causes of malfunctions in complex energy systems is an extremely difficult task, since more than one fault mode may produce similar and possibly undistinguishable patterns of effects. This paper shows how fuzzy expert systems can exploit the available measurements from the data acquisition system to identify different component and sensor fault modes. Real sensor data (mass flow rates, pressures, temperatures, and key operating parameters) are compared to the expected values of the same quantities that are calculated using numerical models of local subsystems. This comparison simply determines if the differences between measured and expected values are “negative”, “zero” or “positive” in fuzzy logic terms. The final objective is to verify the existence of some patterns of these attributes that univocally identify the considered fault modes. These patterns are then implemented as the set of rules forming the knowledge base of a fuzzy expert system. The proposed diagnostic methodology is tested on the gas section of a real combined-cycle cogeneration plant and the effect of measurement noise is also discussed.
Incorporating Remote Capabilities in Undergraduate Lab Instruction
Authors: Agarwala Ranjeet , Jackson Sherion H. , Jackson Andrew E. , Mehta Merwan
Published: May 2009

The goal of the Department of Technology Systems at East Carolina University (1, 2, 3) is to support the economic development requirements of Eastern North Carolina by creating professionals to meet the general engineering and technology needs of its private and public sectors. The various programs in the department emphasize the application of engineering and technology theories to solve real world problems. For this reason students are engaged in hands-on activities beginning with their first semester and do not wait for several semesters or years to experience real engineering activities. During the last three year there has been a tremendous effort to modify and update the curricula of all the department’s programs. Due to the rapid growth of the department in the last few years, the department has embarked on a mission to include distance education (DE) capabilities in its various courses. To accommodate this, various components of the course have been devised as stand alone modules woven together in a distributed environment. This will help sustain and strengthen the enrollment of the department by offering lab centric courses remotely. The model will also minimize the burden of purchase, support and maintenance of lab equipment and help reallocate excessive resources from face-to-face lab instruction. This paper will describe various strategies for integrating a DE lab model into the existing curriculum. The model will be realized through leveraging the exiting DE resources with the proposed model, creating a scalable DE enrollment model (96, 48 students, etc), integrating existing college and university computer hardware and software capabilities with the proposed model.
Optimal Bandwidth Allocation and QoS-Adaptive Control Co-Design for Networked Control Systems
Authors: Ji Kun , Kim Won-Jong
Published: May 2009

In this paper, we present a co-design methodology of dynamic optimal network-bandwidth allocation (ONBA) and adaptive control for networked control systems (NCSs) to optimize overall control performance and reduce total network-bandwidth usage. The proposed dynamic co-design strategy integrates adaptive feedback control with real-time scheduling. As part of this co-design methodology, a “closed-loop” ONBA algorithm for NCSs with communication constraints is presented. Network-bandwidth is dynamically assigned to each control loop according to the quality of performance (QoP) information of each control loop. As another part of the co-design methodology, a network quality of service (QoS)-adaptive control design approach is also presented. The idea is based on calculating new control values with reference to the network QoS parameters such as time delays and packet losses measured online. Simulation results show that this co-design approach significantly improves overall control performance and utilizes less bandwidth compared to static strategies.