bluuebunny/crossref_metadata_2025 huggingface dataset:
Effects of Uncertain Land Availability, Wind Shear, and Cost on Wind Farm Layout
Authors: Chen Le , MacDonald Erin
Published: February 2014

The robust optimization presented in this paper is formulated to assist in early-stage wind farm development. It can help wind farm developers predict project viability and can help landowners predict where turbines will be placed on their land. A wind farm layout is optimized under multiple sources of uncertainty. Landowner participation is represented with a novel uncertain model of willingness-to-accept monetary compensation. An uncertain wind shear parameter and economies-of-scale cost reduction parameter are also included. Probability Theory, Latin Hypercube Sampling, and Compromise Programming are used to form the robust design problem and minimize the two objectives: the normalized mean and standard deviation of Cost-of-Energy. The results suggest that some landowners that will only accept high levels of compensation are worth pursuing, while others are not.
Interacting With a Large Virtual Environment by Combining a Ground-Based Haptic Device and a Mobile Robot Base
Authors: Pavlik Ryan A. , Vance Judy M. , Luecke Greg R.
Published: February 2014

Ground-based haptic devices provide the capability of adding force feedback to virtual environments; however, the physical workspace of such devices is very limited due to the fixed base. By mounting a haptic device on a mobile robot, rather than a fixed stand, the reachable volume can be extended to function in full-scale virtual environments. This work presents the hardware, software, and integration developed to use such a mobile base with a Haption Virtuose™ 6D35-45. A mobile robot with a Mecanum-style omni-directional drive base and an Arduino-compatible microcontroller development board communicates with software on a host computer to provide a VRPN-based control and data acquisition interface. The position of the mobile robot in the physical space is tracked using an optical tracking system. The SPARTA virtual assembly software was extended to 1) apply transformations to the haptic device data based on the tracked base position, and 2) capture the error between the haptic device’s end effector and the center of its workspace and command the robot over VRPN to minimize this error. The completed system allows use of the haptic device in a wide area projection screen or head-mounted display virtual environment, providing smooth free-space motion and stiff display of forces to the user throughout the entire space. The availability of haptics in large immersive environments can contribute to future advances in virtual assembly planning, factory simulation, and other operations where haptics is an essential part of the simulation experience.
Position Control of a Hybrid Actuator With Air Muscles and Spherical MR-Brake
Authors: Senkal Doruk , Gurocak Hakan
Published: February 2014

In this research, we developed a position control system for a hybrid actuator using position, velocity and pressure feedback loops as well as a force-blending algorithm. The actuator uses combination of a spherical MR-brake and three air muscles to create motion in two degrees-of-freedom (DOF). The spherical MR-brake is capable of rotating along three axes and restricts all motion when engaged. The control system helps prevent overshoot and instability in the air muscles by engaging the MR-brake when necessary. It also provides significant improvement in response time by making high-gain PID control of air muscles possible. Such an actuation scheme can be used in a wide-variety of advanced robotics applications such as walking robots, bio-robotics and exoskeletons, where high power, multi-DOF actuation is required in a compact volume.
Optimal Design of Gearboxes in Powertrain of a Hybrid-Electric Off-Road Vehicle
Authors: Roa Sergio Daniel , Blanco Juan Camilo , Muñoz Luis Ernesto
Published: February 2014

For the achievement of an efficient powertrain design of a hybrid electric off-road vehicle, various designs and configurations of the gearboxes were evaluated under an optimal design viewpoint. Due to off-road requirements, it is not possible to use a single fixed gearbox. Design solutions are evaluated according to specific requirements and constraints associated to the design scenario, considering hilly terrain operation of the desired vehicle. In this work the design process and design solutions of the gearboxes in powertrain are presented.
Evaluation of Bimanual Stretched-String Single Object Manipulation for Virtual Assembly With Haptics
Authors: Vyawahare Vikram S. , Stone Richard T.
Published: February 2014

This research attempts to improve the spatial interaction in virtual assembly with a focus on bimanual object manipulation. Using a unique combination of spatial interaction devices namely a kinesthetic haptic device (Phantom Omni®) and a magnetically tracked device (Razor Hydra) each held in one of the user hands; a new interaction technique named ‘Bimanual Stretched-String Single Object Manipulation’ (BS-SSOM) was developed [1]. The BS-SSOM technique decouples positioning and orientation of objects during bimanual single object manipulation in virtual assembly. The distance between the two hands can be varied to control the precision of manipulation. The simulation uses Voxmap Pointshell [2] physically based modeling library. The (BS-SSOM) technique is evaluated with a user study. Three modes of manipulation and 3 task levels are designed to give 9 treatments for evaluation. A method to measure the task completion along with task time and distance covered by each hand in virtual assembly is devised. In order to facilitate long tasks a progressive assembly scheme is implemented. Participants were screened for normal visual acuity, stereopsis and manual dexterity. Results of the user study provide good indicators for evaluation of hypotheses regarding participant performance, realism of interaction, hand motion and effect of task length on utility of the interaction method.
Modeling Thermal Fluctuations of Bio-Filaments With Elastic Rod Theory
Authors: Goyal Sachin
Published: February 2014

Bio-filaments at sub-micron scales such as DNA perform their biological functions via well-regulated structural deformations that involve large twisting and bending. The strain energies associated with these deformations are of the order of the thermal kinetic energies of surrounding solvent molecules. Therefore, the bio-filaments at such small length scales also exhibit large fluctuations in their shape due to the random collisions of the solvent molecules with them. These thermal fluctuations may, on one hand, help the bio-filaments explore functionally desirable configuration space, while, on the other hand, hinder the regulation of their deformations by motor proteins. Nevertheless, it seems indispensable to model the thermal fluctuations to accurately study the dynamics of deformation of bio-filaments. This paper presents the first elastic rod formulation that incorporates the thermal fluctuations by modeling the impacts of solvent molecules as distributed stochastic force. For quasi-static fluctuations, this formulation leverages the simplicity of a rod formulation noted by Anker et al. [1] that allows solving it as an initial value problem (IVP) in single iteration, and yet capturing arbitrarily large (nonlinear) deformations with rigorous description of constitutive laws.
The Gear Bearing Drive: A Novel Compact Actuator for Robotic Joints
Authors: Brassitos Elias , Mavroidis Constantinos , Weinberg Brian
Published: February 2014

Advanced robotics requires a new generation of actuators able to exhibit a number of desirable characteristics ranging from high power density and high efficiency, high positioning resolution, high torque capacity and torsional stiffness, lightweight designs and low-cost packages. In this paper, we present the development and the experimental evaluation of a new actuator, aimed at improving the torque density and mechanical efficiency of actuated robotic joints, and enhancing the portability and effectiveness of robotic systems engaged in biomechanical applications such as rehabilitation robots and wearable exoskeletons. The new actuator, called the Gear Bearing Drive (GBD), consists of a two-stage planetary gear arrangement coupled through the planets and driven by an external rotor brushless motor that is inscribed within the input stage sun gear. This planetary configuration enables for incredible high-speed reductions and allows for embedding the motor directly within the gearbox saving significant space on the actuator length. Our initial experimental prototypes have demonstrated impressive performance with the potential to deliver more than 30Nm of continuous torque with 85% mechanical efficiency and 0.0005 degree of backlash, and up to 200 rpm maximum output speed in a highly compact and robust package.
Analysis of Critical Functionality for Meta Analogy via Performance Specification
Authors: Lucero Briana , Viswanathan Vimal , Linsey Julie , Turner Cameron
Published: February 2014

This research defines the basis for a new quantitative approach for retrieving useful analogies for innovation based on the relevant performance characteristics of critical functions. Analogy matching is made possible by the novel incorporation of Non Uniform Rational B-spline (NURBs) based metamodels enabling the efficient representation of critical function performance. The concept of critical functionality is central to this research effort. Metamodels of the performance of critical functions, obtained from simulations, engineering models (such as bond graphs) and/or experimental data collections, will be organized into a searchable repository of innovative analogies. This approach will enable multiple analogies to be presented to the designer with a quantified match metric related to the desired performance benefit to the design. The impact of this approach for inspiring novel designs will be measured through controlled experiments measuring the impact of the analogies on the innovation of design. The ultimate research goal will be verified using MetaAnalogy via Performance Specification (MAPS) technique at both the conceptual design phase and throughout the design process. Engineering innovation is critical to meet a vast array of challenges including the grand engineering challenges of the 21st century in the form of energy and environmental solutions.
Dimensional Analysis of Dynamic MEMS Micro-Robotic Walking Subject to Orthogonal Actuation and Small-Scale Forces
Authors: Casarez Carlos S. , Ryou Jeong Hoon , Oldham Kenn R.
Published: February 2014

This research evaluates simulated walking micro-robots based on orthogonal lateral and vertical actuators, a common restriction on micro-electromechanical system (MEMS) actuation, and subject to small damping effects and certain small-scale external forces operating on robot feet. Dimensional analysis is used to identify scalable trends in a numerical simulation of a simple walking dynamics model in which lateral and vertical motion are treated as dynamically-uncoupled, the limiting case for orthogonal MEMS actuators. The results of this analysis are that the system damping significantly affects walking speed, while small-scale foot-ground interaction forces other than adhesion have significant effects only over large order-of-magnitude variation in robot size. Results are intended to serve as a design tool for walking micro-robots.
Kinematics and Path Planning of a Six-Degrees-of-Freedom Robot Manipulator
Authors: Mondragon Carlos , Fotouhi Reza
Published: February 2014

This paper introduces a strategy to accomplish pick-and-place operations for a six-degrees-of-freedom (6-DOF) robotic arm attached to a wheeled mobile robot. This research work is part of a bigger project in developing a robotic-assisted nursing to be used in medical settings. The significance of this project relies on the increasing demand for elderly and disabled skilled care assistance which nowadays has become insufficient. Several methods were implemented to make a 6-DOF manipulator capable of performing pick-and-place operations. This paper presents an approach for solving the inverse kinematics problem and planning collision-free paths. An Iterative Inverse Kinematics method (IIK) was introduced to find multiple configurations for the manipulator along a given path. The IIK method takes advantage of a specific geometric characteristic of the manipulator, in which several joints share a common plane. Ten different scenarios with different number and pattern of obstacles were used to verify the efficiency of a path planning algorithm introduced here. Other methods, also implemented in the current project, which describe the manipulator and its capabilities, are presented elsewhere [1]. Overall results confirmed the efficiency of the implemented methods for performing pick-and-place operations for a 6-DOF manipulator.
Digital Origami From Geometrically Frustrated Tiles
Authors: Harnett C. K. , Kimmer C. J.
Published: February 2014

This paper describes “digital origami” from geometrically frustrated tiles: arrays of structures that cannot attain an energetically favorable flat state because of internal constraints. Each tile can typically snap between two symmetric energy-minimizing states, and neighboring tiles are coupled so that a collection of binary tile states determines the local curvature of the entire sheet. Modular structures like these tiles give great advantages in manufacturing and in predictive simulation, and their discrete nature is a good match for digital readout and control of self-folding systems.

The digital origami concept applies to materials from the nanoscale to the macroscale. An example from previous researchers is a metal sheet with an array of dimples that can flex up or down. In this paper we investigate more general techniques that can develop planar sheets into bistable structures. Such methods include installing compressed pieces into a flat sheet of material, or tying together parts of a sheet (smocking). These methods work with a large variety of technologically important materials including circuit boards and semiconductor substrates.

While there are clear benefits to such structures, significant obstacles to design exist in manufacturing, in evaluating their mechanical properties, and in choosing the best arrangement of tile states to match a desired shape. Determining the optimal flipping order of tile states to change the sheet from one shape to another is a sequencing problem analogous to protein folding, and origami from non-planar surfaces is a little-explored area in the fine arts. The paper discusses algorithms for curve-matching with one-dimensional arrays by error diffusion, and shape prediction for two-dimensional sheets with pre-programmed tile states. Low computational cost is required for creating structures that can predict, detect, and even change their own three-dimensional shapes using low-power onboard microprocessors. Motivators for this challenge include shape measurement over a large size range — for example, detecting the changing shapes of biological microstructures or endowing robots with a spatial sense similar to human proprioception — and self-modeling of structural properties for lightweight morphing structures that can strengthen for impact in a given direction using a limited amount of material.
An Inverse Finite Element Method for the Determination of Unsteady Temperatures and Heat Fluxes on Surfaces of 3-D Objects
Authors: Dennis Brian H.
Published: February 2014

The direct measurement of temperatures and heat fluxes may be difficult or impossible on boundaries that are obstructed, such as internal cavities, or exposed to harsh environmental conditions that would destroy the thermal sensors. In such circumstances, one may inversely determine the temperature and heat fluxes on these unknown boundaries by using over-specified conditions on boundaries where such information can be readily collected. This assumes the geometry and material properties of the domain are known. Algorithms for solving these problems, such those based on finite difference, finite element, and boundary element, are well known for the case where measured boundary conditions are not a function of time. In this work, I demonstrate an inverse finite element method that effectively solves this inverse heat conduction problem using over-specified temperatures and heat fluxes that are time varying. The material properties may highly heterogeneous and non-linear. A boundary regularization method in space and time is used to stabilize the method for cases involving errors in temperature and heat flux measurements. Several three dimensional examples are given using simulated measurements with and without measurement errors, to demonstrate the accuracy of the method.
Conceptual Model Study Using Origami for Membrane Space Structures
Authors: Natori M. C. , Katsumata Nobuhisa , Yamakawa Hiroshi , Sakamoto Hiraku , Kishimoto Naoko
Published: February 2014

Some attempts to get efficient membrane space structure designs using various conceptual origami models are introduced, and their basic design considerations to fit their concepts to actual space structural hardware are presented. They cover cylindrical shell elements with axially buckled patterns for inflatable tubes, and deployable flat membrane structures for light weight large aperture spacecraft including their thickness effects and their various variations driven from geometrical dual properties. Some examples of deployable concepts in nature with reference to better designs of membrane space structures are also shown, and some limitations of their origami models are discussed.
On the Energy Stored in Fractional-Order Electrical Elements
Authors: Hartley Tom T. , Veillette Robert J. , Lorenzo Carl F. , Adams Jay L.
Published: February 2014

In this paper, fractional-order electrical elements are considered as energy storage devices. They are studied by comparing the energy available from the element to do future external work, relative to the energy input into the element in the past. A standard circuit realization is used to represent the fractional-order element connected to an inductor with a given initial current. This circuit realization is used to determine the energy returned by both capacitive and inductive fractional-order elements of order between zero and one. Plots of the energy stored versus time are provided. The major conclusion is that fractional-order elements tend to rapidly dissipate much of their input energy leaving less energy for doing work in the future.
Fold Mechanics of Natural and Synthetic Origami Papers
Authors: Rao Abhinav , Tawfick Sameh , Shlian Matthew , Hart A. John
Published: February 2014

To realize engineered materials and structures via origami methods and other folding construction techniques, fundamental understanding of paper folding mechanics and their dependency on paper micro/nanostructure is needed. Using selected papers commonly used in origami designs, we establish the relationship between the mechanical properties of fibrous paper and their corresponding ability to form and retain simple creases and mountain/valley folds. Using natural fiber paper (abaca), synthetic fiber paper (Tyvek), and a metal-fiber laminate paper, we studied how the fold radius depends on the load applied using a controlled rolling apparatus. After folding, we examined the resultant micro- and nanoscale deformation using electron microscopy. In general we found that the fold radius follows a power law, decreasing with the applied rolling force. At a critical strain, each paper exhibits a transition between elastic and plastic behavior, after which the trend asymptotically approaches the minimum fold radius with increased applied force. Finally, we present examples of centimeter-scale two-dimensionally “mountain fold” patterns and relate the folding characteristics observed in these designs to the mechanical properties of the papers in folding.
Teaching Sustainable Design Within a Product Innovation Process in Mexico: Linking Two One-Semester Design Courses
Authors: Borja Vicente , Ávila Cedillo Javier N. , López-Parra Marcelo , Ramírez-Reivich Alejandro C. , Treviño Arizmendi Arturo , Equihua Zamora Luis F.
Published: February 2014

This paper documents the process, the outcomes and the lessons learned from two design courses aimed at incorporating environmental, economic and social concerns during the product development process. These courses are co-taught by professors of the Engineering and the Industrial Design Schools of the Universidad Nacional Autónoma de México (UNAM). Each course lasts one academic semester and includes engineering graduate and undergraduate students from industrial design and engineering.

The two courses are “New Product Development” (NPD) and “Design for Sustainability” (DS). The NPD course runs in collaboration with the University of California at Berkeley (UCB) and it has been taught at UNAM since 2008. The course fosters the development of product concepts that address particular user needs related to sustainability issues and enhance user’s experience and innovation.

The DS course is aimed at introducing students to the most representative approaches, methodologies and tools related to sustainability. DS takes the NPD process as a background, i.e. takes the NPD product concept produced by students and evaluates its environmental impact, and its technical and economic feasibility. Some issues on entrepreneurship and social responsibility are also covered.

For both courses design projects are paramount. Some of the projects carried out by the students during the courses are proposed by students themselves and some others are put forward by companies.

The first part of this paper includes some background information on representative sustainability courses reported in the literature. Then the complete process model comprised by the NPD and DS courses is presented. Some details of the actual courses contents and lecture activities are also described. Representative projects developed within the courses, one of which is now a startup company, are presented. Finally, insights and lessons learned are discussed.
Comparing Legged Locomotion With a Sprung-Knee and Telescoping-Spring When Hip Torque is Applied
Authors: Rao Nikhil , Shen Zhuohua , Seipel Justin
Published: February 2014

Legged locomotion has been a subject of study for many years. However, the role of the knee in whole-body dynamics of locomotion is not well understood, especially for non-conservative dynamics. Based upon a hip actuated Spring-Loaded Inverted Pendulum (Hip-actuated SLIP) model, we develop a more human-like, two-segment leg model with a pin-jointed springy knee, to see what effects a knee has in the context of an applied hip torque. Overall, we find that the governing equations for the two-segment (knee) version have a distinct structure when compared to the telescoping version of SLIP. The two-segment model with a knee spring influences forces acting on the mass center in a more complex way than a telescoping spring. While a wide variation of behavior is possible for the two-segment model, here we focus on comparing the dynamics for a special case when the knee spring resting angle is 90°. For this particular choice of resting knee angle we find that the knee version of actuated SLIP can have similar locomotion dynamics to the telescoping version of actuated SLIP. This result provides one explanation for how animals and robots with multi-segmented legs could produce overall center-of-mass dynamics that are similar to models with telescoping legs. Nonetheless, despite overall similarities for this special case, small differences in the stability of locomotion are still observed. In particular, we find that the knee version tends to be slightly more stable than the telescoping SLIP in terms of the allowable size of perturbations, while requiring higher input power.
A Near-Infrared Spectroscopy Study of Horizontal Vibration and Comfortableness of a Ride
Authors: Watanuki Keiichi , Hirayama Kenta , Kaede Kazunori
Published: February 2014

Comfortableness of a ride is an important issue to passengers and drivers in an automobile. It is difficult to quantify comfortableness of a ride because it is affected by the rider’s emotions and physiology. In this paper, we measure brain activity using near-infrared spectroscopy (NIRS) to examine the features of brain activity that occur when a person is feeling vibration. The results obtained in this study may be used to quantify subjective evaluations of comfortableness of a ride. We measured brain activity during vibrations that are uncomfortable and during vibrations that are not uncomfortable. Uncomfortable vibration and vibrations that were not uncomfortable were determined based on sensory evaluations. Results reveal that oxygenated hemoglobin (oxy-Hb) levels in the prefrontal cortex change when feeling vibration. With uncomfortable vibration oxy-Hb levels declined more than with vibration that was not uncomfortable. In addition, we measured brain activity of riders feeling vibration which evaluation vary among subjects. We found that oxy-Hb of the subjects that feel uncomfortable vibration declined in the prefrontal cortex. Therefore, we inferred that the decline of oxy-Hb in the prefrontal cortex is related to feelings of discomfort.
Particle Swarm Optimization With Crossover and Mutation Operators Using the Diversity Criteria
Authors: Dong Guang , Cooper John
Published: February 2014

Particle Swarm Optimization is a population based globalized search algorithm that mimics the behavior of swarms. It belongs to the larger class of evolutionary algorithms as widely used stochastic technique in the global optimization field. Since the PSO is population based, it requires no auxiliary information, such as the gradient of the problem.

It is known that each particle in the PSO uses only two pieces of information, called the personal best position and the global best position, to update its moving velocity and position by generations. One disadvantage of this algorithm is that it can be easily trapped into some local optimal solutions because of the premature convergence. This may be an issue when solving complex multi-modal functions with multiple local minimums. Hence, the global optimization algorithm should have the ability to prevent being trapped into local optima by keeping wide search space and maintaining the population diversity. In order to improve the performance of the PSO for complex global optimization problems, this paper introduces both crossover and mutation operators to the basic PSO algorithm. The proposed algorithm uses the mechanism that all the particles in the current iteration will have crossover and mutation operations if the diversity criteria of the particles is reduced to be smaller than a predefined limit value. Therefore, the PSO using both crossover and mutation operators can maintain the diversity of population and enhance the search ability as to get better results while solving complex problems. This study adopts the average distance around the swarm center as the diversity measure, and extends the distance metrics to both L1 norm distance and L∞ norm distance.

To verify the usability and effectiveness of the proposed algorithm, it is applied to 12 widely used nonlinear benchmark functions. These examples show that the proposed PSO with crossover and mutation operators using the diversity criteria has better optimization performance than the basic PSO by maintaining the swarm diversity. Moreover, the PSO using the L1 norm distance diversity gives better results than both L2 and L∞ norm distance for most cases.
Torque Load Effects on Mesh and Dynamic Characteristics of Hypoid Geared System
Authors: Wang Yawen , Lim Teik C. , Yang Junyi
Published: February 2014

From the existing experimental results and previous studies, the torque load has great influence on the mesh and dynamic characteristics of hypoid gear drive. To have more insights on the load dependent mesh parameters and dynamic response of hypoid and spiral bevel gear, a load dependent mesh model is developed by using 3-dimensional loaded tooth contact analysis (LTCA). The contact ratio and time-varying mesh parameters including the mesh stiffness, transmission error, mesh point and line-of-action of the mesh force are examined within a wide torque range. Then a nonlinear multi-body dynamic analysis is performed considering the effect of backlash nonlinearity. Simulation results show that the contact ratio and mesh stiffness generally increases as the toque load increases. The effect of torque load on dynamic mesh force is found to be frequency dependent due to the resonance frequency shifts and peak magnitude changes. This study provides an in-depth understanding of hypoid gear tooth load sharing and dynamic behaviors in terms of change in operating load. Therefore, the proposed model can be employed to assist in gear design optimization.
Robust Adaptable Design of Mechanical Products
Authors: Zhang Jian , Chen Yongliang , Xue Deyi , Gu Peihua
Published: February 2014

For an adaptable product, both configuration and parameter values associated with the configuration can be adapted in the product operation stage to satisfy different requirements. This research aims at developing a new design approach to identify the adaptable product whose functional performance is the least sensitive to parameter variations caused by uncertainties. First different configuration candidates in design and different product configurations in operation stage to satisfy design requirements are modeled by a novel hybrid AND-OR tree. Product/operating parameters associated with configurations are also modeled. A two-level optimization method is developed for identifying the optimal design configuration and the parameter values: design configuration optimization for identifying the optimal design configuration and parameter optimization for identifying the optimal parameter values associated with this design configuration. Case study of an adaptable vibratory feeder is developed to demonstrate the effectiveness of the newly developed robust adaptable design method.
Design for FDA: A Predictive Model for the FDA’s Decision Time for Medical Devices
Authors: Medina Lourdes A. , Dávila Saylisse , Okudan Kremer Gül E. , Wysk Richard A.
Published: February 2014

The concept of Design for FDA (DfFDA) has a strong basis on the Food and Drug Administration’s (FDA) regulation for medical devices in the Unites States. In fact; an analysis of the factors that impact the time it takes the FDA’s to provide market approval for medical devices, the product design process model, and Design for X (DfX) methods with overlapping FDA objectives lead to the development of DfFDA as a means to increase awareness about regulatory compliance and promote designers to consider the regulations throughout the development process of medical devices. For doing so, the main objective of DfFDA is to provide regulation-focused guidelines to producers of medical devices. An important part of these guidelines and this paper’s major contribution is the development of a prediction model for the FDA’s decision time. Overall, we want this model to become a tool that allows medical device companies to come up with an accurate estimate of a product’s time-to-market after accounting for the FDA’s decision time. In this work, we provide a comparison and discussion on the adequacy of linear regression models and other non-linear models such as parallel and serial tree-based ensembles for prediction the FDA’s decision time.
A Novel Piezoelectric Multilayer Stack Energy Harvester With Force Amplification
Authors: Zhou Wanlu , Zuo Lei
Published: February 2014

A piezoelectric lead zirconate titanate (PZT) multilayer stack flextensional energy harvester (PZT-Stack-FEH) was designed and characterized in this paper. An elastic flextensional frame for force amplification was optimally designed to transmit more mechanical energy with high efficiency to the PZT-Stack-FEH. Instead of 31-mode single layer piezoelectric component, a 33-mode piezoelectric PZT multilayer stack was employed to increase mechanical-to-electrical energy conversion efficiency. The power delivery ratio of the electrical power dissipated by resistive load over the total generated electrical power from PZT stack was studied. Theoretical analysis and experiments were carried out. The experiment results show that the mechanical-to-electrical energy conversion efficiency of the PZT-Stack-FEH is 19%, 48.6 times more mechanical energy can be transmitted to PZT-Stack-FEH, and 26.5 times more electrical energy can be generated by using the PZT-Stack-FEH than directly applying force to the PZT multilayer stack. The maximum power delivery ratio can attain 70% when the resistive load matches the impedance of piezoelectric stack. The power generation performance of the PZT-Stack-FEH with a proof mass was also studied. Experiment results show that he peak power/acceleration can attain 2400mW/g when the PZT-Stack-FEH is connected with a proof mass of 200 grams and 3280 mW/g with a proof mass of 500 grams.
Techno-Economic Design of Off-Grid Domestic Lighting Solutions Using HOMER
Authors: Johnson Nathan G. , Glassmire John W. , Lilienthal Peter D.
Published: February 2014

Kerosene, candles, and disposable batteries are commonplace in the developing world for rural domestic lighting. These technologies come with negative health and environmental effects that are well documented and often form the basis for engineering design. The immediate and near-term concerns that families experience on a daily basis are also important — economics, quality of light, and quality of service. Families in off-grid rural villages often spend more than half of their energy-related expenditures on domestic lighting. Many technologies have been implemented to provide low-cost and renewable power for lighting, yet these efforts have had a mixed record of success due to persistent financial barriers, issues of consumer acceptance and adoption, and a variety of technical complications. The incidence of these problems can be reduced by completing a techno-economic comparison of alternatives during conceptual design. This paper compares three major categories of off-grid domestic lighting projects: (1) centralized electrification with a micro-grid, (2) battery charging stations, and (3) solar lanterns. The HOMER Energy software is used to compare these options using data gathered from rural villages in Africa. To offer a comparison to existing options available, this paper provides a full financial comparison to a base case — kerosene lanterns — to suggest financing strategies and business models for the options investigated.
Design and Measurement Error Analysis of a Low-Friction, Lightweight Linear Series Elastic Actuator
Authors: Lee Bryce , Orekhov Viktor , Lahr Derek , Hong Dennis
Published: February 2014

Series elastic actuators (SEAs) have many benefits for force controlled robotic applications. Placing an elastic member in series with a rigid actuator output enables more-stable force control and the potential for energy storage while sacrificing position control bandwidth. This paper presents the design and measurement error analysis of a low-friction, lightweight linear SEA used in the Shipboard Autonomous Fire Fighting Robot (SAFFiR). The SAFFiR SEA pairs a stand-alone linear actuator with a configurable compliant member. Unlike most electric linear actuators, this actuator does not use a linear guide, which reduces friction and weight. Unlike other SEAs which measure the force by measuring the spring deflection, a tension and compression load cell is integrated into the design for accurate force measurements. The configurable compliant member is a titanium cantilever with manually adjustable length. The final SEA weighs 0.82[kg] with a maximum force of 1,000[N]. The configurable compliant mechanism has in a spring constant range of 145–512[kN/m]. Having no linear guide and incorporating the load cell into the universal joint both introduce measurement errors. The length error across a parallel ankle joint is less than 0.015[mm] and the force measurement error is less than 0.25% of the actual force. Finally, several changes are suggested for the next iteration of the SEA to improve its usability on future robots.
Design of High Speed Gears, Low Load Gears for Minimizing Gear Whine Noise
Authors: Glover Rodney
Published: February 2014

The main purpose of the supercharger timing gears is to keep the rotors from contacting each other. They are often lightly loaded and designed for low noise. As timing gears, they have by definition a ratio of 1.0. Furthermore, the timing gears are presently spur gears due to the cost of assembling helical gears onto the rotor shafts without allowing timing errors between the rotors. The original timing gear designs were spur gears with contact ratios slightly above 2.0. A major NVH issue has been gear whine noise, because most applications are in luxury vehicles and are evaluated with the hood open and the engine at idle. In this operating condition, the background noise is very low and any tonal gear whine noise is audible. The first effort was to push the gear manufacturing quality to the limits of modern grinding capability. In order to further reduce gear whine noise, the designs have evolved to finer pitch gearing with a contact ratio over 3.0 to reduce transmission error. Micro-geometries were optimized for low transmission error (TE) at low load. OSU Gear Lab’s RMC and LDP became primary tools in optimizing the gear designs for minimum TE. An important factor when increasing the contact ratio is to not increase the sliding friction significantly to keep the fixed oil sump temperature from increasing too much and cause wear issues in operation. Typically, the new high contact ratio spur gear designs in production have reduced the gear whine levels by more than 6 dB and have had very few noise complaints.
The Production Geometric Analysis of the New Type, Spiroid Worm Gear Drive Having Arched Profile
Authors: Dudás Illés , Bodzás Sándor
Published: February 2014

In the last few decades in Hungary, the Budapest University of Technology and Economics and the University of Miskolc have been intensively focusing on the research field of worm gear drives [2, 5].

Our results at the University of Miskolc have also been published in a book published in the USA as well [2].

A new geometric worm gear drive has been developed, that is the conical worm gear drive having arched profiled in axial section [3].

The aim of our publication is to present the advantages, the geometric questions and the possible application fields of this new type worm gear drive.
An Augmented Affective-Cognition Framework for Usability Studies of In-Vehicle System User Interface
Authors: Zhou Feng , Jiao Jianxin (Roger)
Published: February 2014

Vehicles with better usability have become increasingly popular due to their ease of operations and safety for driving. However, the way how usability of in-vehicle system user interface is studied still needs improvement. This paper concerns how to use advanced computational, neurophysiology- and psychology-based tools and methodologies to determine affective (emotional) states and behavioral data of an individual in real time and in turn how to adapt the human-vehicle interaction to meet the user’s cognitive needs based on this real-time assessment. Specifically, we set up a set of neuro-physiological equipment that is capable of collecting EEG, facial EMG (electromyography), skin conductance response, and respiration data and a set of motion sensing and tracking equipment that is capable of eye ball movement and objects that the user interacts. All hardware components and software is integrated into a cohesive augmented sensor platform that can perform as “one coherent system” to enable multi-modal data processing and information inference for context-aware analysis of affective and cognitive states based on the rough set inference engine. Meanwhile subjective data is also recorded for comparison. A usability study of in-vehicle system UI is shown to demonstrate the potential of the proposed methodology.
Determining Vehicle-Level Specifications for a New Car Program Considering Market Environments and Engineering Design Constraints
Authors: Kang Kilmo , Kang Changmook , Hong Yoo S.
Published: February 2014

Designing a marketable automobile for target markets is an important challenge in the globalized market environment. What makes the vehicle planning even more challenging includes various factors such as engineering feasibility, change of market environment, enforced regulations, and ongoing advancement of technology. In this circumstance, the complexity of automobile design arises from the fact that both the target market’s customer preferences and engineering characteristics should be taken into account in balanced as well as quantitative manners.

This paper develops a balanced model for determining vehicle-level specifications for a new car program of an automaker considering both the customer preferences on attributes and the engineering characteristics with design constraints. The proposed model takes into account the interrelation of specifications, advancement of technology, vehicle style concepts, and customer preference changes influenced by the fluctuation of market environments. The major vehicle-level specifications of the next-generation automobile model are determined by maximizing the marketability of an auto with meeting the constructed design constraints. The model was validated with the existing mid-size sedans in the U.S. market.
Towards an Approach for Evaluating the Quality of Requirements
Authors: Mokammel Faisal , Coatanea Eric , Christophe Francois , Ba Khouya Mohamed , Medyna Galina
Published: February 2014

In engineering design, the needs of stakeholders are often captured and expressed in natural language (NL). While this facilitates such tasks as sharing information with non-specialists, there are several associated problems including ambiguity, incompleteness, understandability, and testability. Traditionally, these issues were managed through tedious procedures such as reading requirements documents and looking for errors, but new approaches are being developed to assist designers in collecting, analysing, and clarifying requirements. The quality of the end-product is strongly related to the clarity of requirements and, thus, requirements should be managed carefully. This paper proposes to combine diverse requirements quality measures found from literature. These metrics are coherently integrated in a single software tool. This paper also proposes a new metric for clustering requirements based on their similarity to increase the quality of requirement model. The proposed methodology is tested on a case study and results show that this tool provides designers with insight on the quality of individual requirements as well as with a holistic assessment of the entire set of requirements.
From Silos to Multilingual Science
Authors: Pettit Syril D.
Published: February 2014

Scientists who can communicate across disciplines are essential to fluid translation and must be developed systematically through targeted training.
Prediction and Biochemical Demonstration of a Catabolic Pathway for the Osmoprotectant Proline Betaine
Authors: Kumar Ritesh , Zhao Suwen , Vetting Matthew W. , Wood B. McKay , Sakai Ayano , Cho Kyuil , Solbiati José , Almo Steven C. , Sweedler Jonathan V. , Jacobson Matthew P. , Gerlt John A. , Cronan John E.
Published: February 2014

Through the use of genetic, enzymatic, metabolomic, and structural analyses, we have discovered the catabolic pathway for proline betaine, an osmoprotectant, in
Paracoccus denitrificans
and
Rhodobacter sphaeroides
. Genetic and enzymatic analyses showed that several of the key enzymes of the hydroxyproline betaine degradation pathway also function in proline betaine degradation. Metabolomic analyses detected each of the metabolic intermediates of the pathway. The proline betaine catabolic pathway was repressed by osmotic stress and cold stress, and a regulatory transcription factor was identified. We also report crystal structure complexes of the
P. denitrificans
HpbD hydroxyproline betaine epimerase/proline betaine racemase with
l
-proline betaine and
cis
-hydroxyproline betaine.

IMPORTANCE
At least half of the extant protein annotations are incorrect, and the errors propagate as the number of genome sequences increases exponentially. A large-scale, multidisciplinary sequence- and structure-based strategy for functional assignment of bacterial enzymes of unknown function has demonstrated the pathway for catabolism of the osmoprotectant proline betaine.
The SMC Complex MukBEF Recruits Topoisomerase IV to the Origin of Replication Region in Live Escherichia coli
Authors: Nicolas Emilien , Upton Amy L. , Uphoff Stephan , Henry Olivia , Badrinarayanan Anjana , Sherratt David
Published: February 2014

TheEscherichia colistructuralmaintenance ofchromosome (SMC) complex, MukBEF, and topoisomerase IV (TopoIV) interactin vitrothrough a direct contact between the MukB dimerization hinge and the C-terminal domain of ParC, the catalytic subunit of TopoIV. The interaction stimulates catalysis by TopoIVin vitro. Using live-cell quantitative imaging, we show that MukBEF directs TopoIV toori, with fluorescent fusions of ParC and ParE both forming cellular foci that colocalize with those formed by MukBEF throughout the cell cycle and in cells unable to initiate DNA replication. Removal of MukBEF leads to loss of fluorescent ParC/ParE foci. In the absence of functional TopoIV, MukBEF forms multiple foci that are distributed uniformly throughout the nucleoid, whereas multiple catenatedoris cluster at midcell. Once functional TopoIV is restored, the decatenatedoris segregate to positions that are largely coincident with the MukBEF foci, thereby providing support for a mechanism by which MukBEF acts in chromosome segregation by positioning newly replicated and decatenatedoris. Additional evidence for such a mechanism comes from the observation that in TopoIV-positive (TopoIV+) cells, newly replicatedoris segregate rapidly to the positions of MukBEF foci. Taken together, the data implicate MukBEF as a key component of the DNA segregation process by acting in concert with TopoIV to promote decatenation and positioning of newly replicatedoris.

IMPORTANCEMechanistic understanding of how newly replicated bacterial chromosomes are segregated prior to cell division is incomplete. In this work, we providein vivoexperimental support for the view that topoisomerase IV (TopoIV), which decatenates newly replicated sister duplexes as a prelude to successful segregation, is directed to the replication origin region of theEscherichia colichromosome by the SMC (structuralmaintenance ofchromosome) complex, MukBEF. We providein vivodata that support the demonstrationin vitrothat the MukB interaction with TopoIV stimulates catalysis by TopoIV. Finally, we show that MukBEF directs the normal positioning of sister origins after their replication and during their segregation. Overall, the data support models in which the coordinate and sequential action of TopoIV and MukBEF plays an important role during bacterial chromosome segregation.