bluuebunny/crossref_metadata_2025 huggingface dataset:
Joule Heating Induced Heat Transfer and Its Effects on Electrokinetic Mixing in T-Shape Microfluidic Channels
Authors: Tang Gongyue , Yang Chun , Lam Yee Cheong
Published: May 2009

In this paper, we report numerical and experimental studies of the Joule heating-induced heat transfer in fabricated T-shape microfluidic channels. We have developed comprehensive 3D mathematical models describing the temperature development due to Joule heating and its effects on electrokinetic flow. The models consist of a set of governing equations including the Poisson-Boltzmann equation for the electric double layer potential profiles, the Laplace equation for the applied electric field, the modified Navier-Stokes equations for the electrokinetic flow field, and the energy equations for the Joule heating induced conjugated temperature distributions in both the liquid and the channel walls. Specifically, the Joule number is introduced to characterize Joule heating, to account for the effects of the electric field strength, electrolyte concentration, channel dimension, and heat transfer coefficient outside channel surface. As the thermophysical and electrical properties including the liquid dielectric constant, viscosity and electric conductivity are temperature-dependent, these governing equations are strongly coupled. We therefore have used the finite volume based CFD method to numerically solve the coupled governing equations. The numerical simulations show that the Joule heating effect is more significant for the microfluidic system with a larger Joule number and/or a lower thermal conductivity of substrates. It is found that the presence of Joule heating makes the electroosmotic flow deviate from its normal “plug-like” profiles, and cause different mixing characteristics. The T-shape microfluidic channels were fabricated using rapid prototyping techniques, including the Photolithography technique for the master fabrication and the Soft Lithography technique for the channel replication. A rhodamine B based thermometry technique, was used for direct “in-channel” measurements of liquid solution temperature distributions in microfluidic channels, fabricated by the PDMS/PDMS and Glass/PDMS substrates. The experimental results were compared with the numerical simulations, and reasonable agreement was found.
Development of a General Use Quarter-Vehicle Test Rig
Authors: Langdon Justin , Southward Steve C.
Published: May 2009

This paper discusses the development of an improved design for a tire-coupled quarter-vehicle testing rig. The use of indoor-based simulation tools has become a mainstay in vehicle testing for the automotive and motorsports industries. Testing on a quarter-vehicle rig provides a cost effective means for making accurate and repeatable measurements that enables the user to perform a relatively large number of tests in a short amount of time. A review of current quarter-vehicle test platforms, both commercially available and in academic research labs, indicated that many desired functional requirements were not available. The goal of this effort was to develop a new quarter-vehicle rig with expanded capabilities that are not simultaneously present in the current state-of-the-art. The desired functional requirements are: accommodation of a wide range of actual vehicle suspension components including the tire and wheel, weight transfer due to braking and acceleration, aerodynamic forces, and vehicle roll. The test rig was constructed and tested using a Porsche 996 suspension. The suspension dynamics were characterized by fitting the parameters of a linear dynamic model to experimental response data from the rig. The design and performance of this new quarter-vehicle test rig is shown to be a cost effective solution for meeting the broad range of functional requirements.
Scale-Model Test Rig for Passive and Active Suspension Control Comparison
Authors: Annis Nathanael D. , Southward Steve C.
Published: May 2009

This paper presents the design and validation of an experimental test rig for direct visual and analytic comparison of fully active and semi-active suspension control algorithms using electromagnetic actuation. A linear mathematical model simulation of the test rig is presented, as well as experimental validation test results comparing passive against fully active and semi-active skyhook control algorithms. A variety of fully active and semi-active vibration control methods have been developed for primary suspensions. Our goal is to provide a development platform in which new algorithms can easily be implemented, in a cost effective manner on a physical system, and compared against existing algorithms to determine the performance characteristics of each. This platform will provide a standard of evaluation in which multiple control algorithms can be tested, and will help to simplify the design process.
Dynamic Maskless Holographic Lithography
Authors: Jenness Nathan J. , Wulff Kurt D. , Johannes Matthew S. , Cole Daniel G. , Clark Robert L.
Published: May 2009

Maskless patterning techniques are increasingly implemented in semiconductor research and manufacturing eliminating the need for costly masks or masters. Recent application of these techniques to DNA and cell patterning demonstrates the adaptability of maskless processes. In this paper we present a new lithographic process for dynamically reconfiguring and arbitrarily positioning computer-generated patterns through the use of phase holograms. Similar to current maskless patterning methods this process can achieve pattern transfer through serially tracing an image onto a substrate. The novelty of our process, however, lies in the ability to rapidly fabricate complex micro/nanoscale structures through single-shot exposure of a substrate.
Modeling and Simulation of Milling Frozen Biological Samples by Focused Ion Beam
Authors: Fu Jing , Catchmark Jeffrey M. , Joshi Sanjay B.
Published: May 2009

Focused Ion Beam (FIB) has been used widely for sample preparation in material research and nanoscale device fabrication. The introduction of FIB system to biological samples preparation, especially for frozen samples, provides the potential to produce delicate submicron geometries on the samples, as well as the potential to be fully digitally controlled. In this paper, we first study the ion interactions with water and different cryoprotectants, and the sputtering yields under different conditions are estimated as the milling rate. A geometric simulation model is also proposed which can be used as a process planning tool to perform cryo-sectioning by FIB. Finally, discussions and suggestions for future work are presented.
Objective Ride Comfort Measurement
Authors: Mastinu Giampiero , Gobbi Massimiliano , Pennati Mario
Published: May 2009

The paper presents an innovative dummy conceived to provide an effective tool for an objective vehicle ride comfort evaluation. The first part of the research includes experimental tests on instrumented seats for evaluating the vertical (cushion) and longitudinal (backrest) acceleration between the vehicle seat and the seated human subject. Experiments have been performed by using a vibrating table fitted with a vehicle seat and by seating directly the subjects on vehicles (cars and light trucks) while running on a test track. The test track includes uneven road and different obstacles. Human subjects have been chosen in order to obtain a high variability in the anthropometric features (height, weight, gender, age). Several test have been also performed with the same subject submitted to the same excitation in order to investigate the inter-subject variability and the intra-subject variability. During the study different seats have been compared. From the acquired data, a mathematical model of the system, human subject + seat has been derived and numerically validated by minimizing the error between the measured and the computed accelerations. The corresponding mechanical device has been built, the MaRiCO dummy. The device is fully adjustable in order to simulate the vibrational behaviour of different human subjects. Particular attention has been devoted to the construction of the springs and of the magnetic damper to reduce as much as possible the friction between the moving components. The dummy rests on the seat by means of special elements that, thanks to their compliance and conformation, act as the tight and the back of human beings. An experimental validation of the dummy has been performed. The device, opportunely tuned and seated with the same posture of the corresponding human subject is able to reproduce the acceleration between the subject and both the cushion and the backrest.
Controlling Droplet Vaporization/Condensation for Liquid Supply of Capillary-Based Micromanipulation
Authors: Obata Kenichi J. , Masunari Shin-Ichi , Saito Shigeki , Takahashi Kunio
Published: May 2009

In this paper, an approach to condense micro droplet with aimed volume and to maintain its volume is shown. The approach is performed experimentally by means of controlled temperature sequence. Peltiert element was used to control the temperature of copper surface. Pico litter ordered droplet was observed and its volume was estimated by video image processing. From the heat balance analysis, the availability of condensation strategy and the guiding principle of the design of capillary-based micromanipulator are discussed.
Empathic Lead Users: The Effects of Extraordinary User Experiences on Customer Needs Analysis and Product Redesign
Authors: Lin Joseph , Seepersad Carolyn Conner
Published: May 2009

An experiment was conducted to investigate the effectiveness of empathic lead user analysis for uncovering latent customer needs that could lead to breakthrough product ideas. Empathic lead users are defined as ordinary customers (or designers) who are transformed into lead users by experiencing the product in radically new ways, via extraordinary user experiences. These extraordinary experiences may include modifications of the usage environment or the way in which the customer interacts with the product. A procedure for designing and conducting empathic lead user interviews is introduced in this paper. Results are reported for a trial study in which the empathic lead user technique is compared with verbal and articulated use interviews for a common consumer product (a two-person tent). Empathic lead user interviews are observed to have a significantly positive effect on latent needs discovery in the trial study, leading to a five-fold increase in latent needs discovery relative to articulated use interviews with a prototype and a twenty-fold increase relative to verbal interviews without a prototype. Empathic lead user interviews emerge as a promising tool for supporting innovation and breakthrough concept generation.
Rotational Control of Birefringent Particles Using an Optical Trap
Authors: Wulff Kurt D. , Cole Daniel G. , Clark Robert L.
Published: May 2009

Optical traps have been used in a multitude of applications in biology, such as stretching DNA molecules and bacterial tails, due to their ability to study molecules in solution. In addition to being capable of applying and sensing forces, optical traps also have the ability to accurately apply and sense torques. Birefringent particles experience a torque when trapped in elliptically polarized light which has resulted in rotation rates over 400 Hz. By measuring the frequency content of the exiting beam, the rotation rates can be tracked and controlled. Here we describe an optical trap with feedback torque control that maintains rotational rates in the presence of increasing drag. As a result, this research has the potential to advance the understanding of rotary motor proteins such as F1ATPase.
Function-Based Behavioral Modeling
Authors: Hutcheson Ryan S. , McAdams Daniel A. , Stone Robert B. , Tumer Irem Y.
Published: May 2009

Behavioral models, mathematical models of a system’s ability to meet customer needs, are useful evaluation tools throughout the design process of systems. Currently, behavioral modeling is conducted at a component level. The models used to evaluate a system are associated exclusively with the components used to solve a product’s desired functionality. As a result, it is often difficult to create behavioral models during the early stages of design when these component solutions have not been identified. However, during these early stages of design, information about the desired functionality of the system is known. The objective of the work presented in this paper is to develop a method that uses this information, in the form of functional models, as the basis for creating behavioral models. The paper proposes a five step method for creating the behavioral models from the functional model. Significant contributions from the work include reuse of behavioral model elements based on common functionality, swapping of model elements with varying fidelity, a framework for mathematical concept evaluation and selection and the linking of assumptions made during mathematical modeling to their effects on the functionality of the product and vice-versa. Two examples of the method are included, a summary example of a resistor network and a complete example based on the dynamic modeling of a Formula SAE racecar. Conclusions from the work and examples are presented along with areas of future research.
The Atomic Force Microscope as a Nanoscale Stereo Lithography Machine
Authors: Johannes Matthew S. , Cole Daniel G. , Clark Robert L.
Published: May 2009

Atomic force microscope (AFM) based anodization nanolithography on semiconducting layers is a useful tool for nanoscale fabrication. A custom AFM patterning technique has been created that couples CAD with the lithographic capabilities of the AFM. Designed nanostructures to be deposited on a silicon substrate are rendered as a three-dimensional model using CAD. AFM based anodization nanolithography is then used to replicate the features at the nanoscale using automated voltage bias and humidity modulation as prescribed by the model and dictated by the system. The work presented outlines the advantages and limitations when three-dimensional modeling is combined with nanoscale lithography using an AFM.
Analysis of Engineering Design Journal Sketches and Notations
Authors: Grenier Ashley L. , Schmidt Linda C.
Published: May 2009

Identifying and transferring secrets of engineering design drive innovation within a successful company. In design courses, engineering students rarely use a lab book, a research notebook, or design journal to document anything! During the summer of 2006, a University of Maryland RISE undergraduate research team piloted a study of 12 students’ design journal entries during a Mechanical Engineering senior Capstone design course. Existing note coding schemes from the engineering education researchers were adapted and tested with the goal of inferring cognitive activity. Journal entries revealed individual characteristics about students as learners including: uneven time commitment to design stages, preference for sketching, documentation clarity and individual buy-in to design tools presented in class. Design journal research is a promising path to understanding how students are learning and practicing design.
An Efficient CAD-Integrated Multi-Dimensional Model for Microfluidic Simulations
Authors: Danczyk Josh , Suresh Krishnan
Published: May 2009

Microfluidic devices exhibit high-aspect ratio in that their channel-widths are much smaller than their overall lengths. High-aspect geometry leads to an unduly large finite element mesh, making the (otherwise popular) finite-element method (FEM) a poor choice for modeling microfluidic devices. An alternate computational strategy is to exploit well-known analytical solutions for fluid flow over the narrow-channels of a device, and then either: (a) assume the same analytical solutions for the (wider) cross-flow regions, or (b) exploit these solutions to set-up artificial boundary conditions over the cross-flow regions. Such simplified models are computationally far superior to FEM, but do not support the generality or flexibility of FEM. In this paper, we propose a third strategy for exploiting the analytical solutions: (c) directly incorporate them into standard FE-based analysis via model reduction techniques. The advantages of the proposed strategy are: (1) designers can use standard CAD/CAE environments to model, analyze and post-process microfluidic simulation, (2) well-established dual-weighted residuals can be used to estimate modeling errors, and (3), if desired, one can eliminate the dependency on possibly inaccurate analytical solutions over selected regions. The simplicity and generality of the proposed method is inherited from the model reduction process, so are its theoretical properties, while simultaneously its computational efficiency is inherited from the use of analytical solutions.
Analysis of Team Interaction and Team Creativity of Student Design Teams Based on Personal Creativity Modes
Authors: Kim Myung Sook , Kim Yong Se , Kim Tae Hoon
Published: May 2009

The purpose of this study is to analyze team interaction and team creativity performance for conceptual design activities of student design teams that are composed using personal creativity modes. Experimental group design teams conducted a conceptual design task after teamwork practice activity immediately following self-awareness activity for personal creativity modes. Their design results have been evaluated using novelty and resolution aspects of the Creative Product Semantic Scale. The result shows that the teams in experimental group acquired higher score than those in control group without teamwork practice activity. Also we conducted detailed team interaction analysis of protocol data using Interaction Process Analysis method for a diverse team composed of various creativity modes and a uniform team composed of the same creativity mode. The analysis result of team interaction shows that the interaction patterns of team members in diverse team were very different from individual to individual reflecting their personal creativity modes, while those of uniform team members were almost identical. These findings suggest that knowing team members’ personal creativity modes could improve team creativity and that personal creativity modes could affect the way design team interacts.
Detailed Risk Analysis for Failure Prevention in Conceptual Design: RED (Risk in Early Design) Based Probabilistic Risk Assessments
Authors: Grantham Lough Katie
Published: May 2009

Avoiding product recalls and failures is a must for companies to remain successful in the consumer product industry. Large numbers of failed products result in significant profit losses do to repair or replacement costs as well as untraceable costs of reputation damage among customer bases. Probabilistic risk assessment (PRA) is key to preventing product failures. When risks are adequately identified and assessed the potential product failures can be mitigated and save lives as well as company profit. Risk mitigation is more effective the earlier it can be applied in the design process; therefore, the identification and assessment of risk through PRA techniques is most beneficial to the company when employed early in the design process. This paper presents new techniques for performing four common PRAs, preliminary hazards analysis (PHA), failure mode and effect analysis (FMEA), fault tree analysis (FTA), and event tree analysis (ETA), during the conceptual phase of design, when products have yet to assume a physical form. The backbone for the application of these PRA techniques during the conceptual design phase is the Risk in Early Design (RED) Method. RED generates a listing of potential product risk based on historical failure occurrences. These risks are categorized by function, which enables this preliminary risk assessment to be performed during conceptual design. A risk analysis is performed for a bicycle that demonstrates the powerful failure prevention ability of RED and PRA during conceptual product design with a Consumer Product Safety Commission recall.
Systematic Reverse Engineering of Biological Systems
Authors: Wilson Jamal O. , Rosen David
Published: May 2009

The duality between biological systems and engineering systems exists in the pursuit of economical and efficient solutions. By adapting biological design principles, nature’s technology can be harnessed. In this paper, we present a systematic method for reverse engineering biological systems to assist the designer in searching for solutions in nature to current engineering problems. Specifically, we present methods for decomposing the physical and functional biological architectures, representing dynamic functions, and abstracting biological design principles to guide conceptual design. We illustrate this method with an example of the design of a variable stiffness skin for a morphable airplane wing based on the mutable connective tissue of the sea cucumber.
A Graph-Based Framework for Early Assessment of Functional Failures in Complex Systems
Authors: Kurtoglu Tolga , Tumer Irem Y.
Published: May 2009

In this paper, the Functional Failure Identification and Propagation (FFIP) framework is introduced as a novel approach for evaluating and assessing functional failure risk of physical systems during conceptual design. The task of FFIP is to estimate potential faults and their propagation paths under critical event scenarios. The framework is based on combining hierarchical system models of functionality and configuration, with behavioral simulation and qualitative reasoning. The main advantage of the method is that it allows the analysis of functional failures and fault propagation at a highly abstract system concept level before any potentially high-cost design commitments are made. As a result, it provides the designers and system engineers with a means of designing out functional failures where possible and designing in the capability to detect and mitigate failures early on in the design process. Application of the presented method to a fluidic system example demonstrates these capabilities.
A Method to Correct Pulling Geometry Induced Errors in Single Molecule Force Spectroscopy Measurements
Authors: Rivera Monica , Ke Changhong , Marszalek Piotr E. , Cole Daniel G. , Clark Robert L.
Published: May 2009

In AFM-based single molecule force spectroscopy, it is assumed that the pulling angle is negligible and that the force applied to the molecule is equivalent to the force measured by the instrument. Although this assumption may hold for flexible, compact molecules, studies have shown that it may not be appropriate for fairly rigid molecules, where measured forces can be a fraction of the actual values experienced by the molecule. Because the pulling geometry can substantially influence the values measured by the AFM, we investigate a method to minimize the pulling angle prior to conducting a pulling experiment. The method presented herein uses small circular movements to locate the molecule’s substrate attachment site and reposition the cantilever. By using data gathered from a previous study, we were able to repeatedly align a molecule’s attachment sites via simulation of the program, thereby demonstrating the effectiveness of the alignment method.
Evaluation of a Structural Controls Model of Thermally Driven Cantilever Vibration
Authors: Kennedy Scott J. , Cole Daniel G. , Clark Robert L.
Published: May 2009

This work compares the results of a structural controls based formulation of a micro-cantilever driven by thermal excitation to measured data and weighs the impact of various factors that can affect cantilever measurement. Understanding of the dynamics of small cantilevers such as those used in atomic force microscopy (AFM) is important for many of its applications, especially those that involve observing a cantilever’s thermally driven vibrations. This work considers factors such as the fluctuation dissipation theorem, which places thermodynamic constraints on the spectrum of the thermal driving force, errors associated with photodiode calibration, and cantilever coatings. The structural controls model, which accounts for hydrodynamic loading as a feedback process, is presented and compared to experimental data. Additionally, a discussion of the model’s use for estimating (calibrating) the cantilever stiffness is given.
Design and Innovative Methodologies in a Semantic Framework
Authors: Fernandes Rui , Grosse Ian , Krishnamurty Sundar , Wileden Jack
Published: May 2009

Significant expenditure and effort is devoted to the never ending search for reduced product development lifecycle time and increased efficiency. The development of Semantic Web technologies promises a future where knowledge interchange is done seamlessly in open distributed environments. This paper illustrates how Semantic Web technologies in their current state of development can be effectively used to deploy an infrastructure supporting innovation principles and the engineering design processes. A mechanical design was chosen to model the initial phase of a design project using semantic ontologies. This included a set of design requirements, creating a functional model, and making use of the Theory of Inventive Problem Solving (TIPS). The ontology development strategy is built on a combination of larger domain knowledge ontologies and simple process ontologies. Linked user requirements, engineering design, and functional modeling ontologies facilitated the application of TIPS through a set of semantic rules to generate design recommendations. The developed semantic knowledge structure exemplifies a practical implementation of a functional model which served as a record of the design process and as a platform from which to gain additional usefulness out of the stored information.
A Probabilistic Approach for Extracting Design Preferences From Design Team Discussion
Authors: Ji Haifeng , Yang Maria C. , Honda Tomonori
Published: May 2009

During the formative stage of the design cycle, teams engage in a variety of tasks to arrive at a design, including selecting among design alternatives. A key notion in design alternative selection is that of “preference” in which a designer assigns priorities to a set of design choices. This paper presents a preliminary approach for extracting a projection of aggregated design team preferences from design team discussion. This approach further takes into consideration how the design preferences of a team can evolve over time as the team changes its priorities based on new design information. Two initial models are given for representing the most probable and preferred design alternative from the transcriptions of design team discussion, and for predicting how preferences might change from one time interval to the next. These models are applied to an illustrative, real-world case example.
Risk-Based Resource Allocation for Collaborative System Design in Distributed Environment
Authors: Qiu Yuming , Ge Ping , Yim Solomon C.
Published: May 2009

Risk is becoming an important factor in facilitating the resource allocation in engineering design because of its essential role in evaluating functional reliability and mitigating system failures. In this work, we aim at expanding existing quantitative risk modeling methods to collaborative system designs regarding resource allocation in a distributed environment, where an overlapped risk item can affect multiple stakeholders, and correspondingly be examined by multiple evaluators simultaneously. Because of different perspectives and limited local information, various evaluators (responsible for same or different components of a system), though adopting the same risk definition and mathematical calculation, can still yield unsatisfying global results, such as inconsistent probability and/or confusing consequence evaluations, which can then cause potential barriers in achieving agreement or acceptable discrepancies among different evaluators involved in the collaborative system design. Built upon our existing work, a Risk-based Distributed Resource Allocation Methodology (R-DRAM) is developed to help system manager allocate limited resource to stakeholders, and further to components of the targeted system for the maximum global risk reduction. Besides probability and consequence, two additional risk properties, tolerance and hierarchy, are considered for comprehensive systematic risk design. Tolerance is introduced to indicate the effective risk reduction, and hierarchy is utilized to model the comprehensive risk hierarchy. Finally a theoretical framework based on cost-benefit measure is developed for resource allocation. A case study is demonstrated to show the implementation process. The preliminary investigation shows promise of the R-DRAM in facilitating risk-based resource allocation for collaborative system design using a systematic and quantifiable approach in distributed environment.
UV Nano-Imprint Lithography for Manufacturing Applications
Authors: Choi Jin , Sreenivasan S. V. , Resnick Doug
Published: May 2009

Researchers have demonstrated that imprint lithography techniques have remarkable replication resolution and can pattern sub-5nm structures. However, a fully capable lithography approach needs to address several challenges in order to be useful in nano-manufacturing applications. This paper presents the key technical challenges as well as the progress achieved to-date in these areas. A promising nanoimprint technique that has been previously discussed in the literature is a UV curing technique known as Step and Flash Imprint Lithography (S-FIL). In this article, a variant of the S-FIL process — known as drop-on-demand UV nano-imprint process — that addresses many of the key manufacturing challenges is discussed. This process has the ability to address challenges such as process repeatability in residual layer control, low defectivity, ability to fully automate the lithography process, nano-resolution alignment, and the ability to handle pattern density variations. All nano-imprint lithography techniques essentially replicate the patterns present in a master mold (or template). One of the demanding challenges is the creation of this template. Patterning, metrology, inspection, and defect repair issues relevant to template fabrication are discussed. Finally, with a brief discussion of near-term practical applications in the areas of photonics, magnetic storage, and CMOS devices is presented.
Review, Modelling and Simulation of Two-Mode Hybrid Vehicle Architecture
Authors: Wishart Jeffrey D. , Zhou Yuliang , Dong Zuomin
Published: May 2009

Hybrid vehicle technology is beginning to make a significant mark in the automotive industry, most notably by the Toyota Prius THS-II and its one-mode technology, but also by two-mode architectures recently introduced. GM-Allison, Renault, and the Timken Company have attempted to capitalize on the advantages over simpler series and parallel architectures that the series-parallel configuration confers on the Prius while also improving the design by allowing the powertrain configuration to physically shift and operate in two different modes depending on the driving load. This work provides an overview of the state-of-the-art in two-mode hybrid vehicle architectures, and demonstrates the performance of this technology in comparison to the market-leading Toyota Prius one-mode hybrid vehicle technology and conventional ICE technology. Simulations in the NREL ADVISOR® software compare the performances of the one- and two-mode architectures against a parallel-full design and the ICE baseline for four different drive cycles and a vehicle with varying weight that simulates a commercial vehicle application. A configuration that is a variation of those designed by GM-Allison was chosen as the representative of the two-mode architectures. The performance metric was fuel economy. The fuel economy was measured over the course of the drive cycles: (1) Urban Dynamometer Driving Schedule for Heavy Duty Vehicles (UDDSHDV); (2) New York City Truck (NYCT); (3) City-Suburban Heavy Vehicle Route (CSHVR); and (4) Highway Fuel Economy Test (HWFET). The vehicle model uses a module developed in-house for a Kenworth T400 truck with a payload that varies from empty to completely full. The results demonstrate that the two-mode architecture provides significantly improved performance to that of the conventional non-hybrid design and comparable performance to that of the parallel-full hybrid design. Furthermore, the one-mode design is shown to be sub-optimal for this vehicle type. Development and optimization of the control strategy, which is the direction of the current research, should allow for additional improvement in fuel economy; optimization of vehicular components could result in improvements in acceleration ability, gradeability, and top speed performance, which lags behind the performance capabilities of the conventional powertrain vehicle in these metrics. The study confirms that two-mode architecture presents unique advantages for constantly changing driving cycles and vehicle payloads and represents the future of hybrid vehicle technology.
Evaluating the Use of Cyberinfrastructure in the Classroom to Enhance Product Dissection
Authors: Devendorf Matt , Lewis Kemper , Simpson Timothy W. , Stone Robert B. , Regli William C.
Published: May 2009

Recent cyberinfrastructure initiatives seek to create ubiquitous, comprehensive, interactive, and functionally complete digital environments that consist of people, data, information, tools, and instruments for research communities. With product dissection as our unifying theme, we are forging a cyberinfrastructure to support undergraduate design engineering education through CIBER-U: Cyber-Infrastructure-Based Engineering Repositories for Undergraduates. CIBER-U pairs two of the nation’s leading design repository developers with several active users and their students to realize a high-impact application of cyberinfrastructure in engineering undergraduate curricula involving freshmen through seniors. Specifically, CIBER-U combines product dissection activities at three universities with two digital design repositories, CAD modeling and animation, video, MediaWiki technology, multimedia, and undergraduate summer research experiences to enable cyberinfrastructure-based product dissection activities. Nearly 700 students have participated in the Phase I efforts of CIBER-U, which have focused primarily on generating, capturing, and storing data in two digital design repositories. Lessons learned from these efforts are presented from the students’ perspectives as well as that of the faculty in both engineering and computer science. The implications for implementing CIBER-U on a national scale are discussed along with ongoing research.
Pull-In Behavior of Electrostatically Actuated Multistable Microstructures
Authors: Krylov Slava , Seretensky Shimon , Schreiber David
Published: May 2009

We present an analysis of the electromechanical behavior and stability of a capacitive-based Micro Electro Mechanical Systems (MEMS) device with non-monotonous stiffness-deflection dependence. As an example, we consider a flexible initially curved double clamped micro beam actuated by a distributed electrostatic force. Since the system exhibits both mechanical snap-through buckling and electrostatic pull-in instability, the equilibrium curve has two bifurcation points implying the existence of multiple equilibrium configurations. The multistability phenomenon described in the present work is a result of interaction between mechanical and electrostatic nonlinearities of the system and differs from the electrostatic pull-in based bistability and mechanical bistability associated with the snap-through buckling. The governing equations of the geometrically nonlinear curved Euler-Bernoulli beam are formulated in the framework of the shallow arch approximation. Actuating force is calculated using second order perturbation solution of the Laplace equation for an electric potential. A coupled electro mechanical model is built by the Rayleigh-Ritz method with linear undamped eigenmodes of a straight beam as base functions. After verification of the model results, we analyze the influence of initial geometry of the beam on the location (in terms of actuation voltage and deflections) of the critical points on the bifurcation diagram. It was found that for snap-through to take place, the initial elevation of the beam should be larger than a certain value whereas the existence of electrical pull-in instability is unconditional. In addition, the stable relative deflection of a curved beam is larger than of initially straight beam. Based on the model results, we present an example of a multistable actuator design. Devices of various configurations were fabricated of single crystal silicon using deep reactive ion etching and the existence of multiple stable states and multiple instability points was demonstrated experimentally.
Development of Electric Bicycle Performance Testing Techniques and Adaptable Electric Bicycle Power System
Authors: Stackhouse Richard V. , Dong Zuomin
Published: May 2009

Battery powered electric bicycles and scooters, replacing the heavily polluting scooters with two-cycle internal combustion engines, provide zero-emission transportation for many parts of the world. Annual global sales of electric bicycles have risen from 36,000 in 1993 to over 500,000 in 1999 and to multi-millions today. To facilitate the development of new electric bicycles, a computerized electric bicycle testing facility has been created. Standardized testing cycles for quantitatively measuring the performance of electric bicycles have been developed. Testing results of three representative electric bicycles using the newly introduced electric bicycle testing methods and testing facility are presented. The development of a low-cost, fully Adaptable Electric Bicycle Power System (AEBPS) designed to be quickly adapted to a regular bicycle is also presented. The AEBPS can be attached to a regular bicycle in less than ten minutes, and removed in under five minutes. Performance of a converted bicycle using the AEBPS is evaluated and compared with representative commercial electric bicycles. The work forms the foundation for systematically evaluating different electric bicycle designs and for carrying out design optimization of electric bicycle power systems suitable to different markets and needs.
Characterization of a Novel MEMGyroscope Actuated by Parametric Resonance
Authors: Oropeza-Ramos Laura A. , Burgner Christopher B. , Olroyd Craig , Turner Kimberly L.
Published: May 2009

We present a novel scheme for a robust micro gyroscope excited parametrically that reduces the sensitivity loss due to mismatching in the drive and the sense natural frequencies, which is a common problem in micro gyroscopes based on harmonic oscillators. We demonstrate experimentally that sing a parametric resonance based actuator, the drive-mode signal has rich dynamic behavior with a large response in a large bandwidth. In this way the system is able to induce oscillations in the sense-mode by Coriolis force coupling, despite a clear disparity on their fundamental frequencies. Thus we propose a micro gyroscope that is less sensitive to parameter variations due to its inherent dynamical properties.
Feasibility Study of a Novel Micro-Handling Device Based on Smart Materials
Authors: Pagano Claudia , Fassi Irene
Published: May 2009

Due to their high surface to volume ratio, microsystems are characterized by great superficial forces, which become dominant with respect to inertial ones. Superficial interactions influence fabrication processes as well as working conditions of microsystems and make most of the techniques used at the macrolevel inadequate at the microlevel. In particular, the traditional manipulation techniques are often not suitable for the fabrication of hybrid microsystems and the development of new handling techniques for microcomponents is strongly required. This has aimed a large number of recent studies that have been addressed the possibilities of controlling and exploiting superficial forces in order to manipulate microobjects. In this context, this paper is focused on a new handling system based on the capillary force; in particular, it concerns the first investigations on the use of smart materials for the realization of an innovative manipulation system. A gripper with variable curvature has been theoretically studied and a first prototype has been developed. It has demo good ability in performing accurate pick & place operations of component of the millimetric size. The results obtained from this prototype have, then, encouraged the development of a smaller prototype, able to manipulate objects with micrometric size. Due to the reduced dimensions of the prototype, smart materials have been considered suitable for the actuation of such a gripper. Therefore, different materials and configurations have been conceived and a novel configuration based on electroactive polymers (EAP) has been studied. A feasibility study has been carried out in order to evaluate their functionality and performances as actuator and the results are presented.
Contact Angle Manipulation for Liquid Bridge Based Microgripper
Authors: Chandra Santanu , Batur Celal
Published: May 2009

Manipulation of micron sized components is essential for microassembly. Understanding the dominant adhesive forces in the micro-scale as well as devising techniques to control them is needed in order to design a proper micro manipulation apparatus. A liquid bridge based micromanipulation scheme is presented in this paper. The adhesive forces like capillary and surface tension force are prominent in micro scale due to scaling law and provides sufficient force for pickup of an object. The main problem resides in the systematic release of the object from the gripper surface. The focus of this paper is on the feasibility study of contact angle manipulation by electrowetting method for prompt release of an object. Preliminary results from numerical solution of Laplace-Young equation and CFD analysis shows that by increasing the contact angle a critical contact angle is reached after which Laplace-Young equation does not produce a feasible solution and the CFD analysis results in an unstable solution. This result demonstrates that the contact angle manipulation is capable of breaking a liquid bridge and provides a feasible solution for the release mechanism in microgripping.
Exploring the Use of Functional Models as a Foundation for Biomimetic Conceptual Design
Authors: Tinsley Andrea , Midha Prem A. , Nagel Robert L. , McAdams Daniel A. , Stone Robert B. , Shu L. H.
Published: May 2009

The natural world provides numerous cases for analogy and inspiration. From simple cases such as hook and latch attachments to articulated-wing flying vehicles, nature provides many sources for ideas. Though biological systems provide a wealth of elegant and ingenious approaches to problem solving, there are challenges that prevent designers from leveraging the full insight of the biological world into the designed world. This paper describes how those challenges can be overcome through functional analogy. Through the creation of a function-based repository, designers can find biomimetic solutions by searching the function for which a solution is needed. A biomimetic function-based repository enables learning, practicing and researching designers to fully leverage the elegance and insight of the natural world. In this paper, we present the initial efforts of functional modeling natural systems and then transferring the principles of the natural system to an engineered system. Four case studies are presented in this paper. These case studies include a biological solution to a problem found in nature and engineered solutions corresponding to the high level functionality of the biological solution, i.e., a fly’s winged flight and a flapping wing aircraft. The case studies show that unique, creative engineered solutions can be generated through functional analogy with nature.
A Theory for the Development of Conceptual Functional Models for Automation of Manual Processes
Authors: Nagel Robert L. , Stone Robert B. , McAdams Daniel A.
Published: May 2009

Conceptual design is a vital stage in the development of any product, and its importance only increases with the complexity of a design. Functional modeling with the Functional Basis provides a framework for the conceptual design of electromechanical products. This framework is just as applicable to the conceptual design of automated solutions where an engineered product with components spanning multiple engineering domains is designed to replace or aid a human and his or her tools in a human-centric process. This paper presents research toward the simplification of the generation of conceptual functional models for automation solutions. The presented methodology involves the creation of functional and process models to fully explore existing human operated tasks for potential automation. Generated functional and process models are strategically combined to create a new conceptual functional model for an automation solution to potentially automate the human-centric task. The presented methodology is applied to the generation of a functional model for a conceptual automation solution. Then conceptual automation solutions generated through the presented methodology are compared to existing automation solutions to demonstrate the effectiveness of the presented methodology.
Modeling and Analysis of an Ontology of Engineering Design Activities Using the Design Structure Matrix
Authors: Kumar Pavan , Mocko Gregory
Published: May 2009

In this paper, a published ontology of engineering design activities is modeled and analyzed using the design structure matrix (DSM). Specifically, the ontology analyzed in this research provides a basis for describing engineering design activities and subsequently design processes in an unambiguous manner. However, the proposed ontology lacks a computational representation and the information flow between activities is not adequately described. Thus, complex design processes cannot be represented using the ontology. The design activity ontology is modeled and analyzed using the DSM. First, the information flows between design activities are identified and their inter-relationships are described. Four different cases for representing the flow of information between design activities are modeled. In Case 1 and 2 feedback between information output and information input within an activity is captured. Whereas, in Case 3 and 4 it is assumed that no feedback between output and input exists within an activity. DSM analyses, including partitioning and tearing, are performed on the model. Observations and conclusions drawn from these analyses include the further decomposition of design activities, grouping of design activities, and lack of information flow between seemingly related activities. Based on these observations, recommendations are made to refine the ontology. Finally, additional research is required for developing a computational ontology of design activities.