bluuebunny/crossref_metadata_2025 huggingface dataset:
Addressing ABET Criterion 3c Early in the Curriculum
Authors: Bannerot Richard
Published: August 2009

The assessment of ABET Criterion 3c, related to a student’s ability to “design a system, component or process”, usually comes late in the curriculum since the skills and tools necessary for engineering design are presented throughout the curriculum. However, the so-called “soft” design constraints can be addressed and discussed early in the curriculum, if not actually applied with the design process. This early introduction to these constraints makes it easier to discuss their application later, for example in the capstone course. This paper presents examples of how manufacturability, code and standards, economics, ethics, and sustainability are introduced and student learning is assessed both directly (through homework assignments and exams) and indirectly (with surveys) in an early design class.
Development of Nomograms for the Calculation of the Temperature Distribution in a Membrane Wall
Authors: Walter Heimo
Published: August 2009

The present paper deals with one of the most important structural component in combustion chambers of modern steam generators — the membrane wall. The design of the membrane wall is depending on the operation pressure and the heat flux to the wall. For a correct design the knowledge of the temperature distribution and in this connection the points with the highest temperatures at the membrane wall surface is necessary. In this paper nomograms for the calculation of the surface metal temperature at selected points of the membrane wall are presented. The investigation was done for the two heat transfer mechanisms radiation and convection, different tube diameters, bar thickness and tube pitches. The nomograms are based on a dimensionless temperature and dimensionless membrane bar lengths. One result of the analysis is that the nomograms can be used independent from the tube dimensions. For a fast computer-assisted design of the membrane wall correlations are developed to calculate the dimensionless temperature for the selected points as a function of the dimensionless membrane bar lengths and bar thickness.
Bio-Heat Transfer in a Model Skin Subject to a Train of Short Pulse Irradiation
Authors: Jiao Jian , Guo Zhixiong
Published: August 2009

Thermal analysis of biological tissues subject to a train of ultrashort pulse irradiations was made of developing a combined time-dependent radiation and conduction bio-heat transfer model. A model skin tissue stratified as three layers with different optical, thermal and physiological properties was considered. Temperature response of the skin tissue exposed to a single ultrashort pulse irradiation was firstly analyzed by the finite volume method in combination with the transient discrete ordinates method. This temperature rise was found to reach pseudo steady state within an extremely short time period in which thermal diffusion is negligible. Since the tissue properties were assumed to be constant during a train of pulse irradiation, this temperature rise subject to a single pulse can be employed for repeated pulses. In the same time, Pennes’ equation was employed to study the bio-heat transfer in the meso-time scale. The effects of pulse strengths and repetition rate on the temperature response in the multi-layer skin tissue were investigated.
Simulating Gas-Liquid Flows in an External Loop Airlift Reactor
Authors: Law Deify , Battaglia Francine , Heindel Theodore J.
Published: August 2009

The external loop airlift reactor (ELALR) is a modified bubble column reactor that is composed of two vertical columns that are connected with two horizontal connectors. Airlift reactors are utilized in fermentation processes and are preferred over traditional bubble column reactors because they can operate over a wider range of conditions. Computational fluid dynamics (CFD) simulations can be used to enhance our understanding of the hydrodynamics within these reactors. In the present work, the gas-liquid flow dynamics in an external loop airlift reactor are simulated using CFDLib with an Eulerian-Eulerian ensemble-averaging method in two-dimensional (2D) and three-dimensional (3D) coordinate systems. In addition, models are employed for the interphase momentum transfer drag coefficient and turbulence behavior. The CFD simulations for temporal and spatial averaged gas holdup are compared to the experimental measurements of Jones and Heindel [1] who used a 10.2 cm diameter ELALR over a range of superficial gas velocities from 0.5 to 20 cm/s. The effect of specifying a mean bubble diameter size for the CFD modeling is examined. The objectives are to validate 2D and 3D CFD simulations with experimental data in order to predict the hydrodynamics in an airlift reactor for future studies on scale-up and design.
Strength Criteria for Designing Hybrid-Fiber Reinforced Plastic Gears
Authors: Kawasaki Yoshihiro , Aoyama Eiichi , Hirogaki Toshiki , Ise Tetsurou , Hara Eiji
Published: August 2009

In this study, we investigated the bending fracture characteristic of FRP gears as an important design criterion. Gears made from four kinds of laminated materials were tested: cotton reinforced phenolic resin, cotton-carbon (30%:70%), cotton-aramid (70%:30%, 40:60%), aramid, and glass fiber cloth. Cotton-cloth and cotton-aramid cloth are called hybrid-fiber cloth in this paper. Gears were reinforced by setting the fiber cloth in radial and circumferential directions and were manufactured by hobbing. This results in the same bending fracture strength for all the gear teeth. First, we investigated the tensile strength of the laminated materials because this is a fundamental design criterion for metallic gears. Second, we estimated the bending fracture strength of each gear’s teeth because this is a fundamental evaluation index in the design of gears. Theoretically, the bending fracture strength of a gear is in proportion to the tensile strength of the materials from which it is made. However, in our experiments, we found this was not the case. To discover the cause, we looked at the fracture position on each gear tooth. That of the cotton-carbon gear was more towards the tip of the tooth than the in other gears, and that of the glass fiber gear occurred on the compressive pressure side of the tooth root. We then investigated the shearing strength and compressive strength of the materials because these may have influenced the position of the fracture points. The shearing strength of the cotton-carbon laminated material was low compared with its tensile strength, as was the compressive strength of the glass fiber laminated material. We found that if the shearing strength is low compared with the tensile strength, the position of the fracture that occurs is towards the tip of the gear tooth. If the compressive strength is low compared with the tensile strength, a fracture on the compressive side occurs. Our results show that it is necessary to consider the tensile, compressive, and shearing strength of FRP materials when designing gears made from FRP.
Design Approach for Adaptive Axial Force Control in Gun Drilling
Authors: Klocke Fritz , Wirtz Guido , Veselovac Drazˇen
Published: August 2009

In this paper an adaptive axial force control for gun drilling of small drilling diameters is presented. The system is applicable to CNC drilling and gun drilling machine tools, which are equipped with a fast analog NC input and an axial force measurement system. An online identification algorithm discretely investigates the actual transfer function of the control path. Based on this information proper controller parameters are allocated. Experimental tests of the adaptive control system show the functionality in drilling a material transition from steel 100Cr6 into cast iron ADI 800 and exemplary illustrate the disturbance reaction, introduced by activated changes of the path behavior.
Transitional Trigonometric Functions
Authors: Woolley Ronald Lee
Published: August 2009

Crash pulses in automotive collisions often exhibit acceleration shapes somewhere between a sine and a step function and velocity shapes somewhere between a cosine and a linear decay. This is an example of real world behavior that is only somewhat like the familiar sine, cosine, or tangent shapes so commonly used in physical modeling. To adjust the mathematics to the problem, two familiar ordinary differential equations are merged to create a mathematical transition between trigonometric functions and polynomials by introducing one new parameter. The merged ODE produces a new set of “transitional trigonometry” functions that include both sets of familiar shapes and everything in between. For example, the sine function transitions smoothly into a constant or step function. The corresponding cosine function becomes a straight line. When the sine and cosine are plotted against each other the familiar unit circle undergoes a metamorphosis into a square. Integrals of these transitional trigonometric functions transition into a parabola, cubic polynomial, etc. These functions were developed to model a crash pulse in a vehicle collision, a task for which they work remarkably well. Basically, these functions are able to model a structure with force-deflection properties somewhere between a spring with linearly increasing force and a device that produces a constant force. One wonders what other applications in physics may exist besides crashing cars and what other pairs of physical models (represented by ODEs) might be merged together to produce other new and useful transitions.
A Kinematic/Kinetic Hybrid Airplane Simulator Model
Authors: Fairley Gerard T. , McGovern Seamus
Published: August 2009

A kinematics-based flight model, for normal flight regimes, currently uses precise flight data to achieve a high level of aircraft realism. However, it was desired to further increase the model’s accuracy, without a substantial increase in program complexity, by determining the vertical velocity and vertical acceleration using EUROCONTROL’s Base of Aircraft DAta (BADA) model [1]. BADA is a well-known aircraft performance database model maintained and developed by EUROCONTROL Experimental Centre in France. The hybrid model uses the BADA algorithm to determine the vertical velocity and gives original results for determining the vertical acceleration. The approximate accuracy of these vertical parameters was checked by comparing them with preexisting test distributions [2] and an in-house flight simulator application. The hybrid model uses kinematic algorithms for all other functions and parameters. To obtain specific results, C code was written to access text data from BADA’s collection of approximately one hundred airplanes. Accessing this database causes an increase in overall program execution time that was deemed acceptable due to the infrequency of changing plane types. Also, by examining many airplane trajectories obtained from different BADA airplanes, we determined that the model is accurate enough to uniquely represent many different types of aircraft.
Transient-Dynamic Model of a Metal V-Belt CVT for Ratio Shift Control Applications
Authors: Bhate Rohan , Srivastava Nilabh
Published: August 2009

A continuously variable transmission (CVT) enhances the fuel economy and acceleration performance of a vehicle by allowing the engine to operate at or near its best specific fuel consumption rate for variable driving scenarios. A large volume of work has been reported on the dynamic modeling a metal V-belt CVT system. Most of the models mentioned in literature are steady-state quasi-static equilibrium based or multibody-formalism based, thereby being unsuitable for CVT control applications. Since steady state models fail to accurately capture inertial effects and multibody models present a challenge for control applications due to the large number of bodies involved, the focus of the current work has been to develop a simulation model relatively quick and accurate enough to predict the power transmission behavior and inertial dynamics of a metal pushing V-belt CVT at transient states. The objective of this research is to develop a detailed continuous one-dimensional transient-dynamic model of a metal V-belt CVT system for control applications. The model presented in this work is able to capture the dynamic correlation between the required pulley axial forces and the corresponding transmission ratio. In addition to this, it takes into account detailed inertial effects and predicts the slip behavior and torque capacity of the CVT system under both transient and steady-state regimes. The model proposed in this work would serve as a powerful tool to develop fast, reliable, and accurate controllers for a CVT-equipped driveline to meet the objectives of reduced losses, higher torque capacity, higher vehicle fuel economy and better acceleration performance. The results from the present model subsequently discuss in detail the transient performance of a metal V-belt CVT drive for high torque loading conditions. Various control strategies can be readily implemented with this detailed transient-dynamic model of a metal V-belt CVT system to achieve minimum slip loss and maximum fuel economy and torque capacity.
Dynamics and Control of Electroporation
Authors: Basile Susan , Zhao Xiaopeng , Zhang Mingjun
Published: August 2009

Electroporation has become an important tool for drug delivery such as gene therapy. The technique uses electric pulses to create transient pores in the cell membrane. To ensure proper uptake of targeted molecules, it is essential to create sufficiently large pores, which remain open long enough. In this work, we explore evolution of the pores using dynamical analysis and control of electroporation based on a simplified two-dimensional model. A detailed bifurcation analysis reveals the existence of saddle-node bifurcations, which induce hysteresis into the system dynamics. The bifurcation analysis also sheds light on the relation between the applied voltage and the pore radius. Based on the dynamics and bifurcation analysis, we design a feedback control algorithm that is able to achieve any desired pore size. Numerical examples demonstrate the control strategy is robust. The control algorithm will improve the operation of electroporation in drug delivery.
Porous Media Tumor Model for Light Penetration and Oxygen Diffusion During Photodynamic Therapy
Authors: Premasiri A. , Happawana G. , Rosen A.
Published: August 2009

Photodynamic therapy (PDT) is an FDA approved, effective, and minimally invasive cancer treatment modality with few side effects. PDT requires three major components; photosensitizing agent, activation light, and molecular oxygen. Optimization of PDT for an individual patient requires good therapeutic selectivity and high efficacy, where the design of such an effective protocol is based on the understanding of the interaction of key therapeutic components with tumor tissue. Tumor models expressive of changes during the growth of tumor along with the behavior of PDT components facilitate the above requirement. In this study we have developed a mathematical model considering tumor as a porous medium of solid of and liquid that enables to express characteristics of a growing tumor. The characteristic lengths and the volumes that can be changed in the model represent the dynamic changes during the growth of the tumor. An energy based light transport model is superimposed with the porous media model to yield an analytical equation of light penetration in turbid media. In addition a molecular diffusion model combined with the porous media tumor model provides a second analytical equation yielding molecular oxygen diffusion during PDT. Experimentally available physiological and photophysical data are used to obtain the results from the developed models. The commonly used wavelength for PDT, 635nm and corresponding photophsical parameters for a healthy tissue are used for the calculations. The modeling results reveal an exponential decay of optical power along the direction of light penetration and the characteristic changes in oxygen diffusion during PDT. Further observations include the time dependent changes in photosensitizer photobleaching and the corresponding increase in oxygen diffusion length. The modeling results in both cases show a promising accordance with the available experimental results in literature. The model calculations also reveal the effect of light penetration on oxygen diffusion in PDT milieu adding to the expression of its usefulness.
Design and Development of an Elevating/Articulating Manual Wheelchair Legrest
Authors: Hoffman Allen H. , Couture Eric D.
Published: August 2009

The function of elevating legrests is to reposition a wheelchair user to increase circulation and to redistribute pressure thereby increasing comfort and minimizing the risk of pressure sores. Three categories of wheelchair users can benefit from elevating legrests; those who cannot sense discomfort in their lower extremities (spinal cord injuries), those that lack the physical strength to reposition themselves (muscular dystrophy), and those that lack the coordination to reposition themselves (cerebral palsy). Elevating legrests that rotate about a fixed point lower than the center of the knee will shorten the effective leg length, push against the foot and cause torque at the user’s hip. Raising the center of rotation to coincide with the knee has the undesirable effect of interfering with transfers to and from the wheelchair. To match the motion of the leg, an elevating legrest having a center of rotation below the axis of the knee must articulate (lengthen) when being raised. Currently available articulating designs generally require outside assistance to operate [1, 2] or potentially impede wheelchair transfers. The goal of our work was to design, construct and evaluate a user-operated, elevating legrest that accurately follows the natural motion of the user’s leg.
Engineering as a Tool in Assisted Reproduction: An Investigation Using Mathematical Modelling of Oxygen Transport in the Ovarian Follicle
Authors: Redding Gabe P. , Bronlund John E.
Published: August 2009

The key objective of any Assisted Reproductive Technology (ART) is to provide infertile couples with the maximal chance of producing healthy offspring and there is a large body of research within this field directed toward this objective. However, despite this volume of research attention, the success rates of many procedures such as In-Vitro fertilization (IVF) have improved little since their inception. Engineering principles have not been widely applied to ART and, as a result, it appears that there is great potential for engineering to make a contribution to this field. The objectives of this work were to demonstrate the usefulness of engineering principles in this field via the example of modelling oxygen transport in the preovulatory human ovarian follicle. The results show mathematical relationships between follicular fluid dissolved oxygen levels, follicular vascularity and the developmental potential of the oocyte can be described. These relationships are shown to be consistent with findings reported in the literature. Significant results include the emergence of cut off levels of both follicular vascularity and follicle size below which all eggs will be starved of oxygen. Based on current model parameters these cut off levels are predicted to range from 22–40% and 3.5–4.3 ml (19.0–20.3 mm follicle diameter) for follicle vascularity and volume respectively. These results serve to highlight the potential contribution of engineering in general to ART. The implications of these findings are also discussed as are future improvements for modelling mass transport in the ovarian follicle.
Optimization of Weighting Parameters for an Active Suspension System of a Vehicle
Authors: Fayed Ahmad A. , Trabia Mohamed B. , ElMadany Mohamed M.
Published: August 2009

Optimal control schemes are usually employed to minimize different performance criteria of active suspension system of a vehicle such as, ride comfort and road safety. These factors are usually combined into a single quantity using proper weighting parameters that depend on the designer’s preferences. Generally, the selection of these weighting parameters is based on trial and error, which can be a time-consuming and computationally-intensive process. This paper proposes the use of an approach based on nested optimization loops to automate the selection process of these weighting parameters. The objective of the inner optimization loop is to minimize of the quadratic performance index associated with the original active suspension problem while the objective of the outer optimization loop is to minimize driver’s acceleration, for ride comfort, while maintaining both tire deflection and suspension deflection within acceptable limits. The design variables are the weighting parameters associated with the quadratic performance index used in the optimal control of active suspension. A modified form of Hooke-Jeeves algorithm is used to handle this problem while the penalty function method is used to handle the constraints. Simulation results show that this approach can improve the design process for active suspension of vehicles.
Molecular Dynamic Simulation of Thermal Confinement of Particles
Authors: Bottoni Maurizio , Mantovani Simone
Published: August 2009

The European Space Agency (ESA) in an “Invitation to Tender”, dated August 15, 2006, illustrated a feasibility study of the Interaction in Cosmic and Atmospheric Particle System (ICAPS) experiment. The experiment consists essentially of thermal elements, contained in a cylindrical box, the center of which is a trapping area for thermally confined particles floating in a rarefied gas within the chamber. Thermophoretic forces induced by thermal gradients concentrate particles carried from the gas into the trapping area. Particles are eventually collected from this area. The physical dimensions of the experiment and of its components, temperature gradients and locations the thermal elements within the chamber are free parameters that should be experimentally and numerically investigated to enhance the efficiency of the experiment in collecting particles in the trapping area. To enable numerical investigations of the proposed device a two-dimensional computer program called THERCONF-2D (THERmal CONFinement in 2D) has been build up as a first step towards a full three-dimensional representation of the experiment. This code version describes the displacement due to thermophoresis of tiny particles in a gas-filled domain subjected to a temperature gradient. The behavior of the gas molecules and their interaction with material surfaces and with the particles floating in the gas are modeled with the statistical methods of molecular dynamics, based on the “Direct Simulation Monte Carlo” (DSMC). The computational code has extensive post-processing capabilities for visualization of computational results. After verification of the code, current work is aiming at identifying the optimum combination of physical parameters allowing for the best efficiency of the thermal confinement, minimizing the loss of particles escaping from the collecting area. A variant of the code is being installed on parallel processors. The article presents the state-of-the-art of this computational endeavor.
Yucca Mountain Project Structural Acceptance Criterion for Impact Loading of Waste Packages
Authors: Jaquay Kenneth R. , Anderson Michael J.
Published: August 2009

A methodology is presented for evaluating the structural integrity of metallic nuclear waste disposal containers (waste packages) subject to impact events. The LS-DYNA finite element analysis (FEA) computer code and massively parallel processing (MPP) is used for nonlinear, dynamic-plastic, large-distortion impact simulations. The acceptance criterion is based on minimum-strength, bilinear, stress-strain curves and the ASME Boiler and Pressure Vessel Code primary stress intensity limits. The evaluation uses component stress classifications based on force-moment response trends from a series of reduced-modulus elastic analyses. FEA examples are provided for a waste package that is supported on an emplacement pallet (pallet) and dropped from the transfer vehicle.
Yucca Mountain Project Structural Fragility Estimates for Impact Loading of Waste Packages
Authors: Jaquay Kenneth R. , Anderson Michael J.
Published: August 2009

A methodology is presented for estimating the ultimate structural capability (fragility) of metallic nuclear waste disposal containers (waste packages) subject to impact events. The LS-DYNA finite element analysis (FEA) computer code and massively parallel processing (MPP) is used for nonlinear, dynamic-plastic, large-distortion impact simulations. The fragility estimate for risk assessments uses strain energy concepts, a ductile-rupture damage criterion and tri-linear stress-strain curves adjusted for material cold-forming triaxiality and weldment toughness scatter. FEA examples are provided for waste package impacts on ground support structures.
Simulation of Thermal Conductivity in Fabricated Variable Volume Fraction Aligned Carbon Nanotube Polymer Composites
Authors: Yamamoto Namiko , Duong Hai M. , Schmidt Aaron J. , Wardle Brian L. , Papavassiliou Dimitrios V. , Maruyama Shigeo
Published: August 2009

Thermal conductivities of aligned carbon nanotube (CNT)–polymer nano-composites were estimated using the off-lattice Monte Carlo simulation. High thermal conductivity to density ratio is theoretically and experimentally recognized as one of the exceptional properties of CNTs. Aligned CNTs combined with existing advanced composites are being explored for macro-scale aerospace structures that benefit from thermal tailoring and light weight. Accurate thermal transport models within different polymer nanocomposites, and larger-scale and complexity composites, remain to be developed. The model previously developed for single-walled nanotube (SWNT)-polymer composites was modified to simulate the thermal property of aligned multi-walled nanotube (MWNT)-polymer nanocomposites of different volume fraction. Random walk simulations of thermal walkers are used to determine the interfacial resistance to heat flow inside the nano-composites in the directions parallel and perpendicular to the CNT alignment axis. The thermal equilibrium factor between the MWNTs and the composite matrix material is also determined numerically in this study. The CNT-polymer samples were fabricated for thermal conductivity measurements using two methods: the pump-and-probe method and the infrared microscopy. Aligned SWNT and MWNT forests were grown using chemical vapor deposition (CVD). The MWNTs were mechanically densified up to ∼20% aligned-CNT volume fraction. The MWNT forests were immersed in an aerospace-grade thermoset resin, and cured. Near future work is to compare the simulated effective thermal conductivities of the CNT-epoxy composites with the measured data of the fabricated specimens to determine thermal boundary resistance between CNTs and the polymer.
Prediction of the Effects of Pavement Permeability on the Traffic Noise Generated by Tire and Road Surface Interactions
Authors: Dai L. , Lee H.
Published: August 2009

Porous pavement materials such as asphalt rubber concrete (ARC) have attracted attentions from the researchers and practitioners in road science in the recent years due to their durability and environmental advantages. The porous pavements also show advantages in traffic noise reduction. This research concentrates on an investigation of the effects of the permeability of porous and other pavement materials on the response of the noise generated by the interaction between tire and the pavement surface. Experimental tests are carried out in the field to acquire tire/road noise data for difference pavement materials with implementation of the Close-Proximity CPX method. Lab experiments are performed for examining the permeability of the pavement materials. Empirical relationship between the noise level and permeability of the pavement materials is established. Comparison for the responses of the pavement materials with different permeability is also presented. The research results provide guidance for optimal design of the microstructure of porous pavements to be used for reducing traffic noise.
Numerical Study of the Matching of the Volute With the Last Stages Centrifugal Compressor
Authors: Ji Chunjun , Wang Yu
Published: August 2009

The matching of the volute with the last stage of centrifugal compressors was studied in this paper, based on the numerical flow analysis platform developed with the commercial CFD software NUMECA. Detailed flow structures and main sources of the flow losses were analyzed. Main factors affecting the performance were studied. Results indicate that all those factors, such as the cross sectional area variation, the shape of the tongue, the connection of the outlet pipe with the volute, the ratio of the outlet radius of the vaneless diffuser with the impeller radius and the volute orientation, have great influence on the stage performance. Based on the analytic results, structural modifications were proposed and experimented numerically. Final results indicate that the polytropic efficiency can be increased by as much as 4.5%. The optimal matching of the volute and the last stage diffuser were studied and summarized.
Pre-Reducing the Intermittent Exhaust Noise by Optimizing the Exhaust Pipeline at the Design Stage
Authors: Shi Hushan , Zhao Shengdun
Published: August 2009

The method for pre-reducing the intermittence exhaust noise (IEN) by optimizing the exhaust pipeline at the design stage is proposed. Traditionally, the noise in pneumatic frictional clutch and pneumatic frictional brake (PFC/B) is reduced on the condition of the cylinder and pipeline already both designed and fixed. So the pre-reduction of IEN by optimizing the pipeline can relieve the effort for de-noise by using mufflers. Firstly, this paper adopts the electrical transmission line method to deduce the frequency response function (FRF) of the pipeline. Then the linear predication is used to analyze the FRF. Finally, an optimization method is employed to search the optimum parameters of pipeline. The verified experiment results indicate that the proposed method effectively pre-reduce IEN by 5.0 dB especially 5.8 dB below the high-frequencies from 2 kHz to 16 kHz on the 1/1 octave spectrum.
The Key Techniques for Thermal-Flow-Elastic Coupling Numerical Simulation Platform in Turbines
Authors: Guo Zhaoyuan , Wang Qiang , Dong Ping , Zhou Chi , Feng Guotai
Published: August 2009

Thermal-flow-elastic coupling (TFEC) numerical simulation platform has been an essential platform for designing turbo engines with high performance and efficiency. Generally, TFEC numerical simulation was achieved by predicting thermal and stress fields with finite element methods, while flow fields with finite difference methods, but such calculation was not popular in engineering design, because of too much size of data exchange and lower computing efficiency. However these shortcomings will not exist by using finite difference methods for all of the fields. To establish a three dimensional multifunction numerical simulation platform for turbines for all of the fields, the key technique was studied firstly. The technique included analysis on physical models, establishing of mathematical model equation, usage of curvilinear coordinate platform, construction of high accuracy difference scheme and selection of boundary conditions for multi-field coupling simulation. Then the algorithm including domain decomposition one and parallel one were studied to accelerate the coupling simulation. The purpose was to develop a completed TFEC numerical simulation platform by using of finite difference method and to apply the platform for numerical simulation in turbines. Firstly codes for predicting flow field in passage, thermal and stress fields in solid body were developed. Then a simple TFEC numerical simulation platform for turbines was obtained. The single code for predicting flow field was verified with experimental data, and the other two codes were validated with thermal and elastic analytic solutions respectively. And satisfying results were obtained. Then the code for thermal-flow was validated with experimental data of Mark II blade, and the code for thermal-elastic coupling simulations was validated with a cylinder by an analytic solutions. All of these are good basics for completing TFEC numerical simulation platform using finite difference methods for all of the fields and computing TFEC numerical simulation in a turbo engine.
Research and Applications of Fuzzy-PID Control on PFPL
Authors: Xie Tancheng , Nan Xiang
Published: August 2009

This dissertation mainly introduces Fuzzy-PID Control which are used in the PFPL (Pseudo-flexible Production Line). The servo system plays an important role in the NC machine. The performance of servo system decide the quality of NC machine in very great degree This dissertation research and develop a milling and paring manufacture unit of open CNC system – Numerical control unit of PFPL. By using the GT-SV motion controller, put up the software and hardware platform of NC unit rapidly with module design method and the target-oriented programming idea. Take NC milling machine as the process platform, this dissertation use intellectual PID control method to improve the servo control of motion controller, through the pointing accuracy survey of the milling machine, confirmed the actual effect of Fuzzy-PID control.
Fluid Flow and Heat Transfer Prediction of a Rotating Tapered Inclined Channel
Authors: Basha Mehaboob , Al-Hadhrami Luai M.
Published: August 2009

Fluid flow and heat transfer prediction were conducted to study the three dimensional turbulent flow and heat transfer in rotating tapered inclined channel. Channel orientation is 135° from the rotation direction. Three rotation numbers Ro = 0, 0.1, 0.2 & 0.4 and two inlet coolant-to-wall density ratios 0.1 and 0.40 were investigated, respectively, while keeping Reynolds number constant at 10000. The normalized velocity and temperature fields are presented at two axial locations. The local normalized Nusselt number and spanwise averaged Nusselt number values were reported for three walls; leading, trailing, and top walls. The results show considerable span-wise local Nusselt number variation across the leading, trailing and top walls as the rotation number and density ratio increases.
Integrated Topology and Fiber Optimization for 3-Dimensional Composites
Authors: Weiler Helge , Ottnad Jens , Albers Albert
Published: August 2009

The importance of computer aided engineering in product development processes and research has been increasing throughout the past years. As e.g. energy efficiency and therefore mechanical lightweight structures of new products plays a large role, optimization tools gained more and more importance. Weight reduction can be achieved by a change of the component’s design and by selection of adapted materials. Such an improved utilization of material can be implemented only if there is an accurate knowledge of the loads and the conditions on the material. As modern composite materials can make a clear weight reduction possible, appropriate tools and methods are necessary within the design process. Even for isotropic materials, the design of complex parts is not trivial. For the design of composites, additional parameters have to be considered, such as number and thickness of the plies and the orientation of fibers. Hence, design by intuition leads only in few cases to optimal parts. For the determination of the basic layout of a new design topology optimization can be used. It involves the determination of features such as the number, location and shape of holes and the connectivity of the domain. Today topology optimization is very well theoretically studied and also a very common tool in the industrial design process but is limited to isotropic materials. Several approaches for the determination of optimal fiber orientation have been presented in the past e.g. placing the fibers in the direction of the first main stress. Based on a finite element analysis, a method is presented that uses the orientation of main stresses to determine optimal orientations and thickness relations of plies. It is now applicable to complex 3D geometries. The result is a design proposal for the laminate structure (orientation and thicknesses of plies), taking multi-axial load cases into account. To determine a design proposal for complex 3D laminate structures, the application of both methods, topology and fiber optimization, is appropriate. Regarding an independent serial application of topology and fiber optimization it makes sense carrying out topology optimization in a first step and the determination of fiber orientations in a second step. An integrated approach might show even better results in certain cases. For that, we combined topology and fiber optimization in a two-level approach by optimizing laminate structure within each iteration of topology optimization process. In this paper topology and fiber orientation optimization are integrated into a straightforward, automatic way.
Micro Parts Assembly by Formation Controlled Euglena Group Using Their Phototaxis
Authors: Itoh Akitoshi , Houri Shigehiko , Tamura Wataru
Published: August 2009

This paper describes the automatic manipulation system by the motion controlled mass group of Euglena. The group of Euglena was formed by the scanned blue laser beam. Euglena gather around the blue laser by their positive orientation phototaxis. We can transport the object by Euglena group by making collision to the Euglena group to the object and moving the scanning laser to move the Euglena group. In this study, a plastic rectangular rod was transported to the aiming position by using this system. We have to use visual feedback control program to decide the laser irradiating position to achieve the stable transportation preventing the wear or the adsorption. Simple two-dimensional shaped mechanical parts are assembled by Euglena group. Therefore, we can use Euglena as living micromachines.
Towards Autonomous Robot-Assisted Natural Orifice Translumenal Endoscopic Surgery
Authors: Lehman A. C. , Wood N. A. , Dumpert J. , Oleynikov D. , Farritor S. M.
Published: August 2009

Natural Orifice Translumenal Endoscopic Surgery (NOTES) promises to reduce the invasiveness of surgical procedures by accessing the peritoneal cavity through a natural orifice. Current tools for performing NOTES are based on the flexible endoscopy platform, and are significantly limited in imaging and manipulation by the size and geometry of the natural lumen. For NOTES to revolutionize minimally invasive surgery, new approaches are necessary that enable the surgeon to perform procedures with vision and dexterity equivalent to laparoscopic procedures. An image-guided, two-armed, dexterous miniature NOTES robot has been developed that can be placed into the peritoneal cavity through a transgastric incision. Using this robot, the surgeon has effectively demonstrated tissue dissection in non-survivable animal model procedures. A next step in the development of miniature in vivo robots is the automation of routinely performed, low level surgical tasks. This paper details work towards autonomous tissue dissection using the NOTES robot. As a first step, visual tracking and robot control methods are being developed.
Microfluidic Flow Control Using Induced-Charge Electroosmosis
Authors: Sharp Kendra V. , Davison Scott M. , Yazdi Shahrzad H.
Published: August 2009

Work with dc electrokinetics has demonstrated that is works well for bulk transport of fluid an particles. However, it is difficult to achieve control of individual or groups of particles. This paper investigate the use of induced-charge electroosmosis (ICEO) as a means of providing control over particles within bulk dc electroosmotic flow. ICEO flow develops when an electric double layer is induced by an applied electric field at the surface of a conducting object. Here conducting posts are positioned in a microfluidic channel and ICEO flow develops around them due to an applied ac electric field. A dc electric field is applied across the length of the channel to induce electroosmotic flow past the ICEO region. Around one arrangement of posts the ac and dc flow fields combine to produce a region of recirculation which could be useful for holding a particle or particles within a fixed region of the channel. An alternative arrangement of posts functions to focus the flow into the center of the channel. A numerical model of the system is developed and used to explore means of adapting the ICEO flows to many situations. A method for fabricating a microfluidic system for ICEO flows is presented.
Effects of Mass Distribution and Configuration on the Energetic Losses at Impacts of Bipedal Walking Systems
Authors: Font Josep Maria , Ko¨vecses Jo´zsef
Published: August 2009

Understanding the dynamics of human walking is a complex task due to the interaction of the musculoskeletal and the central nervous systems. Nevertheless, the use of simple models can provide useful insight into the mechanical aspects of bipedal locomotion. Such models exploit the observations that human walking significantly relies on passive dynamics and inverted pendulum-like behaviour. The mechanical analysis of walking involves the study of the finite motion single support phase and the impulsive motion of the impacts that occur at heel strike. Such impacts are dominant events because they represent a sudden topology transition and moreover, they are the main cause of energy consumption during the gait cycle. The aim of this work is to gain insight into the dynamics and energetics of heel strike. We use a concept that decouples the dynamics of the biped to the spaces of admissible and constrained motions at the topology transition. This approach is then applied to a straight-legged biped with upper body. Detailed analysis and discussions are presented to quantify the effects of the mass distribution and the impact configuration on the energetics of walking.
Autoignition Study of JP-8/Air Premixed Mixtures
Authors: Far Kian Eisazadeh , Parsinejad Farzan , Gaureau Matt , Metghalchi Hameed
Published: August 2009

Autoignition and explosion limits of JP-8/air mixtures have been investigated by performing a set of experiments in a spherical vessel. These experiments have been done in high temperatures and pressures with different equivalence ratios. The pressure data were recorded by a Kistler pressure transducer, and intense fluctuations of pressure data were observed during the explosion of the unburned gas zone. Three ionization probes were screwed on the vessel to pinpoint the arrival of the flame to the wall and any kind of abnormal signal from these devices could be a reason of autoignition in the end gas. There is a specific range of temperatures and pressures in which explosion occurs. It was concluded that JP-8/air mixtures are very sensitive to a specific range of temperature rather than pressure.
Potential Benefits of Plug-In Hybrid Electric Vehicles for Consumers and Electric Power Utilities
Authors: Himelic Jim B. , Kreith Frank
Published: August 2009

Plug-in hybrid electric vehicles (PHEVs) have the potential of substantially reducing petroleum consumption and vehicular CO2 emissions relative to conventional vehicles (CVs). The analysis presented in this article first ascertains the cost-effectiveness of PHEVs from the perspective of the consumer. Then, the potential effects of PHEVs to an electric utility are evaluated by analyzing a simplified hypothetical example. When evaluating the cost effectiveness of a PHEV, the additional required premium is the most important financial parameter to the consumer. An acceptable amount for the additional upfront costs will depend on the future costs of gasoline and the on-board battery pack. The need to replace the on-board battery pack during the assumed vehicle lifetime also affects the allowed premium. A simplified unit commitment and dispatch model was used to determine the costs of energy and the CO2 emissions associated with PHEVs for different charging scenarios. The results show that electricity can be used to charge PHEVs during off-peak hours without an increase in peak demand. In addition, the combined CO2 emissions from the vehicles and the electric generation facilities will be reduced, regardless of the charging strategy.
Calculating the Phonon Modes of Graphene Using the 4th Nearest Neighbor Force Constant Method
Authors: Tsegaye Mikiyas S. , Hopkins Patrick E. , Ghosh Avik W. , Norris Pamela M.
Published: August 2009

Graphite has always been a very important material both industrially and academically due to its physical structure. But ever since the isolation of Graphene (a single sheet of Graphite) a few years ago, it’s been one of the most widely studied molecular systems for its potential applications in nano-electronics and other break-through areas. Some of the desirable traits of Graphene are its high thermal and electronic mobility, and its low noise properties. This paper outlines a standard method for calculating phonon dispersion curves in Graphene by making use of force constant measurements. This information is usually obtained from approximations of inter-atomic potentials, which involve derivatives of simplified potential approximations between every atom in Graphene to get the force constant tensors. In this paper, the measured values for the force constants are used in a mathematically rigorous way to calculate the Graphene phonon dispersion curves.
Monte-Carlo Simulation of Pressure Propagation in Elastic Arteries: Proposing a New Algorithm for the Clinical Assessment of Carotid-Femoral PWV
Authors: Mookerjee A. , Al-Jumaily A. M. , Lowe A.
Published: August 2009

A Monte-Carlo simulation is developed to study the pressure propagation characteristics in a representative healthy randomly selected human population. Normal distribution sets are defined for different anatomic and physiological parameters based on data available in literature. Random input parameter sets are then generated from these distributions. A mathematical model is then used to simulate the pressure propagation characteristics in large elastic arteries defined by these input parameters. The pressure wave characteristics are then analysed to estimate carotid-femoral pulse wave velocity. Predictions closely match clinically observed trends.
Vascular Diseases and Arterial Pressure Wave Propagation
Authors: Mookerjee A. , Al-Jumaily A. M. , Lowe A.
Published: August 2009

The propagation of pressure pulses between the carotid and the femoral artery is studied by calculating a pressure ratio (PR) between these locations. This ratio is parameterized into different features to permit a quantitative comparison between the PRs. The results obtained from such comparison suggest that it would be possible to non-invasively identify the size and severity of atherosclerotic plaque deposits by studying the features of the carotid-femoral PR.