bluuebunny/crossref_metadata_2025 huggingface dataset:
Design and Modeling of Liquid Gallium Contact RF MEMS Switch
Authors: Liu Qingquan , Tien Norman C.
Published: November 2010

Due to the high power density and local temperature increase on nanoscopic asperities of solid metal contacts, traditional MEMS contact switches suffer from contact welding, pitting, electromigration and oxidation. Particularly, when MEMS switches are used to handle high power, solid metal contacts pose serious limitation on the contact reliability. A self-healing RF MEMS switch, which utilizes liquid gallium contacts to take the place of the traditional solid metal-to-metal contacts, is proposed in this paper. Electrostatic actuation is used to drive a silicon nitride bridge with upper electrodes. When the bridge is pulled down, liquid gallium droplets work as an interface between the upper and lower contact electrodes. The loss of the gallium droplets can be avoided due to the unwettability of the material surrounding the contact electrodes. The switch is fabricated using a surface micromachining process. A coupled-field finite element analysis (FEA) is used to model the electric current, heating and thermal conduction of the contacts. The model includes deformable gallium droplets with 4 μm base diameter. The two sides of the droplets are connected to the upper and lower solid metal contact electrodes, respectively. By using the FEA models, the electric and thermal characteristics of the gallium droplets featuring a variety of geometric parameters have been studied. 1 A current handling capability of the liquid gallium contact is verified by the FEA models.
Experimental Heat Transfer Enhancement for Single Phase Liquid Micro-Channel Cooling Using a Micro-Synthetic Jet Actuator
Authors: Fang Ruixian , Jiang Wei , Khan Jamil , Dougal Roger
Published: November 2010

The present work experimentally investigates the thermal effects of a synthetic jet actuator on the heat transfer performance of single-phase flow confined in a microchannel heat sink. The heat sink consisted of a single rectangular microchannel 500 μm wide, 300 μm deep and 26 mm long. Deionized water was employed as the cooling fluid. A synthetic jet actuator with a 100 μm diameter orifice was placed right above the microchannel and 5 mm downstream from the channel inlet. A Unimorph piezoelectric disc bender was employed as the synthetic jet actuator. The effects of the bulk microchannel flow Reynolds number, the synthetic jet operating voltage and frequency on the microchannel heat transfer performance are being investigated. The Reynolds number ranges from 100 to 500. The actuator driving voltage and frequency ranges in 20–180Vp-p and 10–150 Hz respectively. The results from the case without synthetic jet are compared to those with synthetic jet. It shows that the thermal effects of the synthetic jet are functions of the jet driving voltage, frequency, as well as the bulk mass flow rate in the microchannel. For the case of Reynolds number equal 177, around 24% enhancement is achieved under specified jet operating conditions for a single synthetic jet.
Particle Manipulation Inside a Grooved Microfluidic Channel
Authors: Chen Hsiu-hung , Gao Dayong
Published: November 2010

The manipulation of particles and cells in micro-fluids, such as cell suspensions, is a fundamental task in Lab-on-a-Chip applications. According to their analysis purposes in either the pre- or post-processing stage, particles/cells flowing inside a microfluidic channel are handled by means of enriching, trapping, separating or sorting. In this study, we report the use of patterning flows produced by a series of grooved surfaces with different geometrical setups integrated into a microfluidic device, to continuously manipulate the flowing particles (5 to 20 μm in diameters) of comparable sizes to the depth of the channel in ways of: 1) concentrating, 2) focusing, and 3) potential separating. The device is fabricated using soft lithographic techniques and is composed of inlets, microfluidic channels, and outlets for loading, manipulating and retrieving cell suspensions, respectively. Such fabrication methods allow rapid prototyping of micron or submicron structures with multiple layers and replica molding on those fabricated features in a clear polymer. The particles are evenly distributed in the entrance of the microchannel and illustrate the enriching, focusing, or size-selective profiles after passing through the patterning grooves. We expect that the techniques of manipulating cell suspensions from this study can facilitate the development of cell-based devices on 1) the visualization of counting, 2) the visualization of sizing, and 3) the particle separating.
Thermal Properties of PVP Cryoprotectants With Nanoparticles
Authors: Hao Baotong , Liu Baolin , Rong Senjie , Zhou Yan , Gao Zhixin
Published: November 2010

Vitrification is an effective way for the cryopreservation of cells and tissues. The critical cooling rates for vitrification solution are relatively high. It is reported that nanoparticles can improve the heat tranfer properties of solutions. To increase the heat transfer coefficient of aqueous cryoprotectant solutions, HA nanoparticles were added into PVP solutions (50%, 55%, 60%, w/w). The glass transition temperature, devitrification temperature and specific heat of PVP aqueous solutions with/without HA nanoparticles (0.1%, 0.5% and 1%, w/w) were measured by differential scanning calorimeter (DSC) at the cooling rate of 20°C/min and warming rate of 10°C/min. The change of density of above solutions with temperature was determined by using a straw that can reveal the volume change of solutions. The thermal conductivity was calculated based on the experimental data. A device that can be used to measure the thermal conductivity of vitrification solutions with/without nanoparticles was developed in this study. The results showed that the glass transition temperature, devitrification temperature and specific heat of PVP aqueous solutions with HA nanoparticles are larger than that without HA nanoparticles. The thermal conductivity of solutions with HA nanoparticles is larger than that without HA nanoparticles at a specific temperature. The lower the temperature, the smaller the difference of thermal conductivity between solutions with and without HA nanoparticles. The calculated thermal conductivity meets the measured data well.
The Influence of Edge Structure on the Thermal Conductivity of Graphene
Authors: Bi Kedong , Chen Yunfei , Wang Yujuan , Chen Minhua
Published: November 2010

Non-equilibrium molecular dynamics (NEMD) simulation method is used to investigate the in-plane thermal conductivity of graphene with different structures. The simulation results demonstrate that, as the length of simulated region increasing, the in-plane thermal conductivity of graphene will become larger. Through investigating the influence of width and edge structure on the in-plane thermal conductivity of graphene, it is also found that the thermal conductivity of wider simulated sample is higher than that of the narrower, and with similar length, the in-plane thermal conductivity of armchair graphene is a little higher than that of zigzag one. The effect of temperature on the thermal conductivity of graphene is also studied in this work.
A Simple Cryomicroscopic Method to Measure the Size of Intracellular Ice Crystals
Authors: Han Xu , Ma Hongbin , Critser John K.
Published: November 2010

Investigating the factors influencing the characteristics of intracellular ice formation (IIF) is of critical importance for cryopreservation and cryosurgery techniques. However, for the detection of the size of intracellular ice crystals, ∼10nm-0.1μm, there exist serious technical and theoretical difficulties. In this study, a cryomicroscopic method was established to measure the size of intracellular ice crystals in mouse oocytes during their warming processes by investigating the melting point depression of the intracellular ice crystals from extracellular ones. Using the Gibbs-Thomson relation, the size of intracellular ice crystals was calculated and the results range from 4–28 nm, when the molality of the extracellular ethylene glycol and NaCl ranges from 0 to 4m and 0.15 to 0.6m, respectively, and the cooling rate is 100K/min.
Investigation of Nanopillar Wicking Capabilities for Heat Pipes Applications
Authors: Zhang Conan , Hidrovo Carlos H.
Published: November 2010

Since Moore’s prediction in 1965, transistor count density on computer chips has grown exponentially and roadmaps for future industry growth still project exponential development for the next decade. With higher transistor densities, greater heat flux dissipation is required in order for performance to keep par with chip development. However, it is theorized that current cooling systems would not be able to cope with heat fluxes of future computer chips. Microchip heat management systems can be either active or passive. Active systems require an external driving component that increases the system’s complexity and ultimately power consumption. Heat pipes are passive fluidic systems, which are more robust and easier to implement than their active counterparts. Recirculation of the coolant in a heat pipe is done passively by means of a wicking structure that induces capillary flow from the condenser to the evaporator. However, there are many limiting factors associated with heat pipes based on the wick dimensions, fluid selection and orientation. At CPU chip operating temperatures the most significant limitation is the capillary limit. This limitation must be addressed in order to meet future computer chip heat dissipation requirements. In order to find an optimal geometry that would maximize the capillary flow, a theoretical model was developed using a rectangular pillar array. Surface tension forces induce a capillary flow that is opposed by viscous stresses from the pillars. Due to the regular and well-defined geometry of the pillar array, an ab initio approach can be used to model this flow, rather than resorting to Darcy’s flow and empirical permeability correlations. Predicted values of maximum flow rate were obtained from this theoretical model. This model and its results are directly applicable to carbon nanotube (CNT) and nanowire (NW) based wick structures. To validate the merit of nanostructure wicks for use in heat pipes, experimental data was collected to show the capillary limits of various nanowicks. The capillary limit of a wick was associated with the heat flux at which the wick cannot sustain the fluid flow necessary for heat removal and burnout occurs. When a baseline wick was experimentally compared to a nanowick, it was found that due to the difference in thickness of the wicks, the baseline wick provided higher flow rates. However, when the data were normalized to produce velocity values, the nanowick was found to have a higher velocity than the baseline wicks.
Beetle Inspired Electrospray Vapor Chamber
Authors: Zhao Yuejun , Boreyko Jonathan B. , Chiang Meng-Han , Baker Christopher H. , Chen Chuan-Hua
Published: November 2010

We present the proof-of-concept for a biomimetic electrospray vapor chamber (BEVAC) which can potentially eliminate the wick structures and thermal interface materials used in conventional vapor chambers, and enable direct cooling of the backside of a microprocessor. This vapor chamber has a beetle-inspired superhydrophobic condenser with hydrophilic bumps on which condensate of the working fluid accumulates. The condensate is returned to the evaporator by electrostatic forces (electrospray atomization). We have demonstrated this novel liquid return mechanism with an open-system BEVAC prototype in which an external voltage is applied between a wickless evaporator and a microfabricated condenser with hybrid wettability.
Experimental Study of Flow and Heat Transfer Characteristics in Silicon-Based Corrugated Microchannels
Authors: Tang Huimin , Wu Huiying
Published: November 2010

In this paper, the silicon-based corrugated microchannels used for the heat transfer enhancement were fabricated by MEMS technology for the first time. Both the flow and convective heat transfer characteristics of the deionized water through these corrugated microchannels were investigated experimentally, and comparisons were performed between corrugated microchannels and straight microchannels with the same cross-sectional aspect ratio (height-to-width ratio) and same hydraulic diameter. Experimental results showed that both the flow friction and Nusselt number in corrugated microchannels increased considerably compared with those in straight microchannels, and this increase became enlarged with the increase in the Reynolds number. With the same pumping power, using corrugated microchannels instead of straight microchannels caused the reduction in the total thermal resistance. The heat transfer enhancement mechanism of the corrugated microchannels was discussed. The results presented in this paper help to design the high efficiency integrated chip cooling system.
A Numerical Study on Separation Characteristics of Magnetic Particles in Magnetophoretic Chip Microchannels
Authors: Wu Xinyu , Wu Huiying
Published: November 2010

In this paper, a two-dimensional dynamic model describing the separation behaviors of magnetic particles in magnetophoretic chip microchannels integrated with double-side symmetric and asymmetric soft magnets is proposed and solved with the combining use of the finite element method and the fourth-order Runge-Kutta method. The dynamic characteristics of magnetic particles during the separation process, including the trajectories of magnetic particles, the capture time and capture efficiency are analyzed. The impacts of the geometrical configurations, fluid velocity and magnetic field intensity are also studied. The results show that the trajectories of the magnetic particles in microchannels are oscillatory because of the alternative magnetic force and this oscillation is more obvious for asymmetric positions of the soft magnets. The oscillatory motion of the particle leads to the increase of the moving distance and delay of the capture time. The capture time depends on the geometrical configurations, the initial positions and the dynamic characteristics of the particles. It is also found that under the same strength of magnetic fields there is nearly no difference on the capture efficiency for symmetric and asymmetric configurations. With the increase of fluid velocity, the capture efficiency drops drastically at low flow rates and decreases slowly at high flow rates. The distance between soft magnets and microchannel walls has the similar influence on capture efficiency. It is expected that the results presented in this paper are helpful for the design and optimization of magnetophoretic separation microsystems.
A Novel Driving Force for Nanodevices
Authors: Guo Zeng-Yuan , Cao Bing-Yang , Hou Quan-Wen
Published: November 2010

Design and construction of nanomotors are one of the most attractive fields in nanotechnology. Following the introduction of a novel concept of the thermomass, the relative mass of a phonon gas based on the Einstein’s energy-mass relation, the continuum and momentum conservation equations for the phonon gas are established to characterize the hydrodynamics of the phonon current in a solid. Like the gas flows in the porous mediums, the phonon current in a dielectric solid imposes a driving force on the solid framework atoms, which can be calculated quantitatively and can be applied to actuate nanomotors. We also predict the dynamic behavior of a nanomotor made up of multi-walled carbon nanotubes in terms of molecular dynamics simulations. A shorter single-walled carbon nanotube with a larger diameter, as a mobile part, surrounds a longer single-walled carbon nanotube with a smaller diameter working as a shaft. When a phonon current passes through the inner shaft, the outer nanotube will translate along and/or rotate around the shaft depending on the chiralities of the carbon nanotubes. The motion traces are found to depend on the chirality pair regularly. This type of nanomotor may be promising because they are directly driven by thermal energy transport.
On the in Vitro Hyperthermia of Magnetic Fluid in AC Magnetic Field
Authors: Jiang Junfeng , Hong Ruoyu , Zhang Xiaohui , Li Hongzhong
Published: November 2010

Hyperthermia therapy for cancer has attracted much attention nowadays. The study on the heat transfer in the magnetic fluid and the tumor is crucial for the successful application of magnetic fluid hyperthermia (MFH). Water-based Fe3O4 magnetic fluid is expected to be a most appropriate candidate for MFH due to the good biocompatibility, high saturation magnetization, super-paramagnetization and high chemical stability. In this paper, we explore the heat generation and transfer in magnetic fluid which is placed under an AC magnetic field. It is found that the amplitude and the frequency of alternating magnetic field, particle size and volume fraction have a pronounce influence on maximum temperature of hyperthermia.
Manipulation of the Droplet and Its Application
Authors: Lin Bingcheng , Qin Jianhua
Published: November 2010

A simple and robust method based on pneumatic PDMS microvalve that can be used to manipulate and process individual droplets in microfluidic devices was presented. By incorporating pneumatic microvalves into microfluidic devices, we developed modules that enable to control the formation of droplets, variation of droplets size and composition, reproducible and efficient fusion of droplets. By intermittently switching on and off microvalve, individual droplets can be generated on demand. The size of individual droplets can be flexibly and precisely tuned from hundreds of picoliter to a few nanoliter by varying the time of on-state of microvalve. By expanding the number of aqueous flow channels and building the corresponding microvalves, arrays of chemically distinct droplets can be easily produced via switching on the corresponding microvalves sequentially. When a pair of droplets are generated synchronously and then brought together in a confluence channel, controlled fusion of droplets can be achieved reproducibly and efficiently. (Figure 1)
Generating Renewable Electric Power and Reducing Carbon Footprint by Converting Low-Grade Heat to Electrical Energy
Authors: Halsband Adam
Published: November 2010

Recent technological developments in expander design and next generation refrigerants have made implementation of the Organic Rankine Cycle (ORC) a viable strategy for converting low grade heat into valuable amounts of recoverable, green electrical power. This green process reduces the typical plants carbon footprint. A brief review of the technical drivers of a typical ORC design will be followed with examples of waste heat energy sources in a typical 50 MMGPY biofuels plant. A Case History will be presented for potential energy sources to drive the process that will include 1.) 15 psig steam / condensate return 2.) Boiler stack gas 3.) Dryer stack gas emissions with expected converted electrical energy yields. Impact of energy savings and reducing total plant carbon emissions will also be addressed.
Fuel-Specific On-Load Boiler Cleaning Solutions in Waste Incineration Plants: Challenges, Concepts, Experiences
Authors: Mueller Christian , Frach Manfred , Tirkschleit Marc , Tandra Danny , Breeding Charlie
Published: November 2010

The range of fuels fed to waste incineration plants extends from well-sorted domestic refuse through mixed waste fractions to fuel mixtures that may additionally contain various types of hazardous waste and biomass. This diversity results in a great number of fuel and ash compositions. Among these are fuels with a high calorific value as well as with a low calorific value and simple fuel ashes just as highly problematic fuel ashes. The latter can lead to increased slagging in the combustion chamber and fouling in the open passes of waste incineration plants as well as accelerated corrosion. The plant operator is consequently faced with considerable challenges associated with unscheduled boiler downtime and production losses. The paper describes how fuel specific process know-how is applied in combination with fully automated, efficient onload boiler cleaning systems to control the slagging issues. The paper describes a system which utilizes water as the cleaning medium. The system allows the targeted cleaning of waste incinerators during operation. This paper points out challenges faced by plant operators and suppliers of boiler cleaning technology caused by the heterogeneous fuel composition, and describes in well monitored case studies how these challenges can be successfully met.
Energy-From-Waste and Dioxin Emission Control: Is There a Role for PVC Separation?
Authors: Venezia Domenico , Joshi Samuel , Van Brunt Michael , Szurgot Andrew
Published: November 2010

The role that chlorine and polyvinyl chlorine (PVC) plays in dioxin emissions from municipal solid waste (MSW) combustion has been studied and debated for 25 years. Despite energy-from-waste (EfW) facilities’ dramatic emission reductions following implementation of USEPA’s Maximum Achievable Control Technology (MACT) Guidelines, the PVC/dioxin relationship remains a source of controversy. The issue is whether removal of PVC from waste to be combusted will result in further dioxin emission reductions, as waste separation proponents allege. This paper uses the large volume of post-MACT emission testing data to describe the relationship between MSW chlorine content and dioxin emissions at operating EfW facilities and thereby determines whether PVC separation is likely to be an effective component of a dioxin emission reduction strategy. The paper also shows chlorine and PVC contents and trends in MSW, reviews dioxin formation/destruction/collection mechanisms in EfW facilities, and presents emission data as a function of EfW facility designs. The paper concludes that dioxin emissions at existing EfW facilities are insensitive to MSW chlorine content and that pre-combustion PVC removal offers no discernable emission reduction benefit.
2,400 Tons Per Day Refuse Derived Fuel Facility With Advanced Boiler and Air Pollution Control Systems
Authors: Abrams Richard F. , Toupin Kevin , Costa John T. , Popovic Ned
Published: November 2010

A greenfield Refuse Derived Fuel (RDF) facility in Alliance Ohio will process 2,400 Tons Per Day (TPD) of Municipal Solid Waste (MSW) and Construction & Demolition Debris (C&D). The Ohio EPA has issued the final air permit for the facility. There will be two equipment trains to handle the material each consisting of Riley Power’s Advanced Stoker™ boiler, Turbosorp® dry scrubber, and Regenerative Selective Catalytic Reduction (RSCR®) nitrogen oxides (NOx) control system. The key parts of the “chute to stack” equipment represent a significant advancement in technology when compared to past facilities, as demonstrated by the designation by the State of Ohio as an “Advanced Energy Project”. The Riley Advanced Stoker™ boiler has unique design features to ensure high efficiency, corrosion resistance, and fuel flexibility while at relatively low cost. The use of the Turbosorp will result in lower emissions of lead, other volatile heavy metals, and mercury than for a typical spray dryer/baghouse (SDA) system. Acid gas removal is also superior to an SDA system while utilizing less lime reagent and power. The RSCR follows the Turbosorp as a “low dust” SCR but with auxiliary energy consumption about 85% lower than a typical low dust, tail end SCR. The RSCR will reduce NOx and Carbon Monoxide (CO) emissions to low values when compared to other facilities producing energy from waste. This paper will describe the design basis for the system including fuels to be processed, steam flow and conditions, and emissions. A detailed description of the technologies will also be presented.
Analysis of Thermal Plasma-Assisted Waste-to-Energy Processes
Authors: Ducharme Caroline , Themelis Nickolas
Published: November 2010

Thermal plasma torches convert electricity to high-temperature thermal energy by applying a high voltage across a flowing gas stream. Plasma torches are used extensively for producing metallic and ceramic coatings and also for vitrifying hazardous materials, such as asbestos-contaminated wastes. In the last decade, several thermal plasma processes have been proposed for treating municipal solid wastes (MSW). This research is based on a critical analysis of previous work by the Earth Engineering Center and on published reports and examines the possibilities for the proposed thermal plasma (TP) processes to be recover energy from MSW as an alternative to the conventional waste-to-energy (WTE) by grate combustion. In particular, this study will investigate two prominent thermal plasma technologies that are presently under development: The Alter NRG “Westinghouse” process in the U.S. and the Europlasma process in France. The environmental impacts and the technical economic aspects of plasma-assisted WTE processes will be compared to the traditional process of MSW combustion on a moving grate.
Controlling a Simulated Robot Using Machine Learning Techniques
Authors: Becker Jonathan , Purohit Aveek , Sun Zheng
Published: November 2010

USARSim group at NIST developed a simulated robot that operated in the Unreal Tournament 3 (UT3) gaming environment. They used a software PID controller to control the robot in UT3 worlds. Unfortunately, the PID controller did not work well, so NIST asked us to develop a better controller using machine learning techniques. In the process, we characterized the software PID controller and the robot’s behavior in UT3 worlds. Using data collected from our simulations, we compared different machine learning techniques including linear regression and reinforcement learning (RL). Finally, we implemented a RL based controller in Matlab and ran it in the UT3 environment via a TCP/IP link between Matlab and UT3.
Meta!Blast: A Serious Game to Explore the Complexities of Structural and Metabolic Cell Biology
Authors: Wurtele Eve S. , Bassham Diane C. , Dickerson Julie , Kabala David J. , Schneller William , Stenerson Mark , Vasanth Achyuthan
Published: November 2010

Knowledge of cellular structure and function has increased dramatically with the advent of modern molecular and computational technologies. Helping students to understand cellular dynamics is a major challenge to educators. To address this challenge, we have developed the Kabala Engine, an open source engine based on OpenSG (http://www.opensg.org) and VRJuggler (http://www.vrjuggler.org). This engine is designed to enable biologists, and indeed any domain expert — chemists, artists, psychologists — to create virtual interactive worlds for teaching or research. As a proof-of-concept, we have used this engine to create Meta!Blast, a virtual plant cell containing a prototype chloroplast in which students can enter, activate the light reactions, including electron excitation, and create molecular oxygen and ATP.
Intuitive Measurement Interface for Simplified Mesh Models for Rapid Conceptual Design
Authors: Noon Christian , Newendorp Brandon , Zhang Ruqin , Winer Eliot , Oliver Jim , Duncan Jerry , Gilmore Brian
Published: November 2010

Conceptual design involves generating hundreds to thousands of concepts and combining the best of all the concepts into a single idea to move forward into detailed design. With the current tools available, design teams usually model a small number of concepts and analyze them using traditional Computer-Aided Design (CAD) analysis tools. The creation and validation of concepts using CAD packages is extremely time consuming and unfortunately, not all concepts can be evaluated. Thus, promising concepts can be eliminated based on insufficient time and resources to use the tools available. Additionally, these virtual models and analyses are usually of much higher fidelity than what is needed at such an early stage of design. To address these issues, an desktop and immersive virtual reality (VR) framework, the Advanced Systems Design Suite (ASDS), was created to foster rapid geometry creation and concept assessment using a unique creation approach which does not require precise mating and dimensioning constraints during the geometry creation phase. The ASDS system removes these precision constraints by using 3D manipulation tools to build concepts and providing a custom easy-to-use measurement system when precise measurements are required. In this paper, the ASDS framework along with a unique and intuitive measurement system are presented for large vehicle conceptual design.
A Novel Haptic Rendering Algorithm for Stable and Precise 6-DOF Virtual Assembly
Authors: Liu Muli , Wang Dangxiao , Zhang Yuru
Published: November 2010

This paper presents a novel algorithm for six-degree-of-freedom (6-DOF) haptic rendering, providing a fast, stable and precise virtual assembly. This algorithm simplifies large and complex CAD models into simple geometric primes, to accelerate the collision detection and therefore the refresh rate. Analytic approach is employed to simulate the virtual assembly. The common assembly process is decomposed into two basic types of manipulations, axis-alignment assembly and face-mating assembly. Some special assembly features (thread, spline and gear, etc) are described in special parameters. The algorithm has been implemented and interfaced with a 6-DOF PHANToM Premium 3.0. We demonstrate its performance on force display of the mechanical assembly. The object with low clearances can be assembled, and the continuous feedback force can be guaranteed at a constant frequency of 1 kHz.
Evaluation of Physical Simulation Libraries for Haptic Rendering of Contacts Between Rigid Bodies
Authors: Glondu Loeiz , Marchal Maud , Dumont Georges
Published: November 2010

Haptic rendering has opened a new range of virtual reality applications, enabling a human user to interact with a virtual world using the sense of touch. This kind of interaction enables to enhance applications such as computer-assisted design, where 3D manipulations are part of the system. However, building an application with an accurate haptic feedback is still challenging, especially for interactions between rigid bodies, where stiff contacts can only be displayed with a high simulation frequency. This paper presents the possibilities of implementation of a modular haptic display system that relies on two main components: a physical simulation part and a haptic rendering part. For that purpose, we define a generic coupling approach that enables to perform haptic rendering using admittance haptic devices, through a scaling interface that cleanly separates the physical simulation and the haptic rendering system of units. Four physical simulation libraries are evaluated with respect to haptic rendering quality criteria, based on their behavior in four discriminant test cases. We show that the proposed approach leads to a modular, generic and stable haptic application.
Interface Design and Display Modalities to Improve the Vehicle Inspection Process
Authors: Cairco Lauren , Ulinski Amy C. , McClendon Jerome , Bloodworth Toni , Matheison James , Hodges Larry F. , Summers Joshua
Published: November 2010

There is a direct need in industry to improve the in-production vehicle inspection process and to support mobility for inspection stations. In this paper we present a novel interface design implemented on three multi-modal prototype systems, in which design was based on results from an initial field study we conducted. The design of these systems incorporate two main objectives: 1) enforce a systematic check on each of the items on the list to reduce missed items and 2) facilitate mobility in that the tools used to assist in inspection can be installed at one area and then later easily moved to another area. Our novel graphical software interface aims to enforce systematic checks through incorporation of a system-directed delivery of the checklist items with options for error correction and support of dynamic inspection, where items identified for inspection may differ among checkpoints. We have designed three hardware configurations that support our interface, with aims to achieve mobility from one inspection area to another, leave both hands free for inspection, and incorporate a more convenient way to refer to the list while conducting an inspection. This paper additionally presents preliminary feedback and suggestions for improvement from a pilot study conducted on our interface implemented on three hardware configurations. In the future we plan to incorporate the suggestions from the pilot study and to conduct a more formal evaluation on our multi-modal systems.
A Spline-Like Haptic Tool for Exploration and Modification of Digital Models With Aesthetic Value
Authors: Covarrubias Mario , Antolini Michele , Bordegoni Monica , Cugini Umberto
Published: November 2010

This paper describes a multimodal system whose aim is to replicate in a virtual reality environment some typical operations performed by professional designers with real splines laid over the surface of a physical prototype of an aesthetic product, in order to better evaluate the characteristics of the shape they are creating. The system described is able not only to haptically render a continuous contact along a curve, by means of a servo controlled haptic strip, but also to allow the user to modify the shape applying force directly on the haptic device. The haptic strip is able to bend and twist in order to better approximate the portion of the surface of the virtual object over which the strip is laying. This device is 600mm long and is controlled by 11 digital servos for the control of the shape (6 for bending and 5 for twisting) and by two MOOG-FCS HapticMaster devices and two additional digital servos for 6-DOF positioning. We have developed additional input devices, which have been integrated with the haptic strip, which consist of two force sensitive handles positioned at the extremities of the strip, and a capacitive linear touch sensor placed along the surface of the strip, and four buttons. These devices are used to interact with the system, to select menu options, and to apply deformations to the virtual object. The paper describes the interaction modalities and the developed user interface, the applied methodologies, the achieved results and the conclusions elicited from the user tests.
Using 3D Sound for Providing 3D Interaction in Virtual Environment
Authors: Ortega-Gonza´lez Vladimir , Garbaya Samir , Merienne Fre´de´ric
Published: November 2010

In this paper we describe a proposal based on the use of 3D sound metaphors for providing precise spatial cueing in virtual environment. A 3D sound metaphor is a combination of the audio spatialization and audio cueing techniques. The 3D sound metaphors are supposed to improve the user performance and perception. The interest of this kind of stimulation mechanism is that it could allow providing efficient 3D interaction for interactive tasks such as selection, manipulation and navigation among others. We describe the main related concepts, the most relevant related work, the current theoretical and technical problems, the description of our approach, our scientific objectives, our methodology and our research perspectives.
A Modular Implementation of Wii Remote Head Tracking for Virtual Reality
Authors: Pavlik Ryan A. , Vance Judy M.
Published: November 2010

Virtual reality (VR) environments based on interactive rendering of 3D computer graphics often incorporate the use of position and orientation tracking on the user’s head, hands, and control devices. The Wii Remote game controller is a mass-market peripheral that can provide a low-cost source of infrared point tracking and accelerometer data, making it attractive as a PC-based virtual reality head tracking system. This paper describes the development of an extension to the Virtual Reality Peripheral Network (VRPN) software to support the use of the Wii Remote game controller as a standard tracker object in a wide range of VR software applications. This implementation permits Wii Remote-based head tracking to directly substitute for more costly commercial trackers through the VRPN and VR Juggler Gadgeteer tracker interfaces. The head tracker provides up to 100Hz of head tracking input. It has been tested in a variety of VR applications on both Windows and Linux. The discussed solution has been released as open-source software.
Femtosecond Laser–Assisted Cataract Surgery with Integrated Optical Coherence Tomography
Authors: Palanker Daniel V. , Blumenkranz Mark S. , Andersen Dan , Wiltberger Michael , Marcellino George , Gooding Phillip , Angeley David , Schuele Georg , Woodley Bruce , Simoneau Michael , Friedman Neil J. , Seibel Barry , Batlle Juan , Feliz Rafael , Talamo Jonathan , Culbertson William
Published: November 2010

An image-guided, femtosecond laser can create precisely placed, accurate cuts in the eye to improve cataract surgery.
News from the Brain: The GPR124 Orphan Receptor Directs Brain-Specific Angiogenesis
Authors: Dejana Elisabetta , Nyqvist Daniel
Published: November 2010

A G protein–coupled receptor might represent a new therapeutic target for vascular pathologies in the central nervous system.
Cutting Calories Is Not Always Best
Authors: Bentley-Lewis Rhonda
Published: November 2010

Prenatal and postnatal malnutrition impairs pancreatic β-cell formation in male and female rats.
Spreading the word on sports concussion: citation analysis of summary and agreement, position and consensus statements on sports concussion
Authors: Alla Sridhar , Sullivan S John , McCrory Paul , Hale Leigh
Published: November 2010

Background

The growing concern over concussion in sports has led to the publication of five major summary and agreement, position and consensus statements since 2000. The dissemination of information from these statements is largely unknown and difficult to quantify, but their impact on the research community can be quantified by analysing the number of citations to these key publications. The purpose of this review is to report the number and pattern of citations to the key published statements on sports concussion.

Methods

Web of Science, Scopus and PubMed were searched from 2000 to mid-December 2009 using two different search strategies. The first strategy used the search terms ‘concussion’ and ‘first author’ of the statement article, while the second used the ‘title’ of the target article as the key search term.

Results

The publications resulting from the three ‘Concussion in Sport’ (CIS) group conferences were cited by 532 journal articles, while the National Athletic Trainers' Association position statement was cited 123 times. The highest number of citations to each of the five identified statements was seen in 2009.British Journal of Sports Medicinewas the most frequently cited journal.

Conclusion

The citation analysis of the key statements on sports concussion has shown that the target papers have been widely cited in the research literature, with the highest number of citations being from the publications arising from the CIS group conferences. The authors have shown their preference to cite source articles published in theBritish Journal of Sports Medicine.
Greater peak rearfoot eversion predicts foot orthoses efficacy in individuals with patellofemoral pain syndrome
Authors: Barton C J , Menz H B , Levinger P , Webster K E , Crossley K M
Published: November 2010

Objective

There is growing evidence for the provision of foot orthoses when treating individuals with patellofemoral pain syndrome (PFPS), and prescription is frequently based on the assessment of foot posture/function. However, evaluation of the link between abnormal foot posture/function and foot orthoses outcomes has previously been limited to static alignment measures and has produced inconsistent findings. In this study, the ability of baseline foot kinematics associated with pronation to predict marked improvement 12 weeks following foot orthoses prescription in individuals with PFPS was evaluated.

Methods

26 individuals with PFPS were issued with prefabricated foot orthoses, and patient-reported level of improvement was documented at 12 weeks. Potential predictors of marked improvement at 12 weeks were measured during walking at baseline and included forefoot dorsiflexion and abduction, and rearfoot eversion.

Results

Of the 25 participants who completed the study, seven (28%) reported marked improvement with the foot orthoses after 12 weeks. Discriminant function analysis revealed a greater peak rearfoot eversion to be the only significant independent predictor of marked improvement.

Conclusion

These findings provide preliminary evidence that greater peak rearfoot eversion is predictive of marked improvement 12 weeks following prefabricated foot orthoses prescription in individuals with PFPS. Therefore, foot orthoses may be most effective in the subgroup of people with PFPS and increased dynamic foot pronation.
Analysis of risk scoring for the outpatient management of acute upper gastrointestinal bleeding
Authors: Chan John C H , Ayaru Lakshmana
Published: November 2010

Objective

To determine whether the Glasgow–Blatchford bleeding score (GBS) or pre-endoscopy Rockall score was better at accurately identifying patients with acute upper gastrointestinal bleeding (AUGIB) who were at low risk of the need for clinical intervention and death and therefore suitable for outpatient management.

Design

Retrospective database and case note review of all patients admitted to the emergency departments with AUGIB from 1 January 2008 to 31 December 2009.

Setting

Two tertiary centre teaching hospitals.

Patients

432 patients met the inclusion criteria.

Intervention

None.

Main outcome measure

Clinical interventions (blood transfusion, endoscopic therapy and surgery) and death.

Results

Of 432 patients, 40 (9.3%) had a GBS of 0 and none required intervention or died. In contrast, 13/104 patients (12.5%) who had a pre-endoscopy Rockall score of 0 and 23/125 patients (18.4%) who had a complete Rockall score <3, required clinical intervention. The performance of the scores at these cut-offs were: GBS (sensitivity 100%, specificity 16.1%, positive predictive value (PPV) 37.8%, negative predictive value (NPV) 100%, accuracy 82.3%), pre-endoscopy Rockall (sensitivity 91.2%, specificity 32.0%, PPV 41.2%, NPV 87.5%, accuracy 70.9%) and complete Rockall (sensitivity 84.5%, specificity 50.7%, PPV 55.8%, NPV 81.6%, accuracy 76.2%). For prediction of the need for intervention or death, the accuracy of the GBS (0.82; 95% CI 0.78 to 0.86) was superior to the pre-endoscopy Rockall score (0.71; 95% CI 0.67 to 0.76).

Conclusion

The GBS but not the pre-endoscopy Rockall score identifies patients with upper gastrointestinal bleeding who may be suitable for outpatient management, therefore potentially allowing for more efficient use of hospital resources.
Exposure to temporary employment and job insecurity: a longitudinal study of the health effects
Authors: Virtanen Pekka , Janlert Urban , Hammarström Anne
Published: November 2010

Objective

This study analysed interactions between job insecurity and temporary employment and health. We tested the violation hypothesis (whether permanent employment increases the health risk associated with job insecurity) and the intensification hypothesis (whether temporary employment increases the health risk associated with job insecurity) in a longitudinal setting. Previous research on this topic is scarce and based on cross-sectional data.

Methods

A population cohort (n=1071) was surveyed at age 30 and age 42. Exposure to temporary employment during this 12-year period was elicited with a job-time matrix and measured as the score of 6-month periods. Exposure to job insecurity was measured according to the perceived threat of unemployment. Health at follow-up was assessed as optimal versus suboptimal self-rated health, sleep quality and mental health. In addition to sociodemographics and baseline health, the analyses were adjusted for exposure to unemployment, non-employment and self-employment during the 12-year period.

Results

26% of participants had been exposed to temporary employment. The effect of job insecurity on health was the same in the exposed and unexposed groups, that is the violation hypothesis was not supported. Non-significant interactions between the exposures and all health outcomes also indicated null findings regarding the intensification hypothesis.

Conclusions

These findings suggest that perceived job insecurity can lead to adverse health effects in both permanent and temporary employees. Policies should aim to improve work-related well-being by reducing job insecurity. Efforts towards ‘flexicurity’ are important, but it is equally important to remember that a significant proportion of employees with a permanent contract experience job insecurity.
Canadian west coast fjords and inlets of the NE Pacific Ocean as depositional archives
Authors: Dallimore Audrey , Jmieff Danielle G.
Published: November 2010

The west coast of Canada is one of the major fjord coastlines of the world, hosting about 150 fjords which are locally known as inlets. Much of the coastline remains remote without extensive research, and this paper summarizes what is known of the Canadian west coast fjord environments. Two fjord regimes are recognized along the British Columbia coastline. Mainland fjords drain high mountains and ice fields with sediment input from snowmelt and glacier runoff in spring and summer. By contrast, the inlets on Vancouver Island are in a milder marine climate, and sediment input occurs mostly during heavy rains of autumn and winter. Due to unique oceanographic conditions and shallow sills at the mouth of some Vancouver Island inlets, anoxic bottom waters exist which allow the preservation of annually laminated sediments. Studies of these annually laminated sediment archives over the past decade, including two international drill ship investigations, have characterized the deglacial, sea-level and palaeoenvironmental history of the British Columbia coastal area. These coastal depositional archives have also advanced our knowledge of the cyclical nature of the NE Pacific ocean and climate system, as well as given evidence of infrequent, yet significant abrupt changes that characterize it.
Pollen analysis of Holocene sediments from Loch Etive, a Scottish fjord
Authors: Cundill Peter R. , Austin William E. N.
Published: November 2010

This paper outlines one of the first attempts to analyse the detailed pollen content of the marine sediments from a fjord (sea loch) located on the west coast of Scotland. The site chosen was in the Bonawe Deep, part of the upper basin of Loch Etive, and 2.3 m depth of sediments were sampled. These sediments were examined for their fossil pollen content and a pollen diagram was constructed from the results. The interpretation of the pollen record was supported by seven radiocarbon dates which demonstrated that the sediments accumulated over the last 8–9 ka of the Holocene. The pollen diagram was divided into three pollen assemblage zones. The lowest zone ET1 (
c
. 9–7.3 ka BP) was dominated by pollen of
Betula
,
Pinus
and
Corylus
, zone ET2 (
c
. 7.3–1.2 ka BP) contained a wide range of woodland pollen taxa (mainly
Betula
,
Pinus
,
Quercus
,
Alnus
and
Corylus
) and the uppermost zone ET3 (1.2–0 ka BP) was distinguished by fewer tree pollen taxa and increased values of open habitat taxa, particularly
Calluna
. The pollen diagram showed the development of vegetation during the Holocene which correlated well with existing results from studies of peat or freshwater lake sediments sampled in the west of Scotland. The only significant differences were the higher concentrations of
Pinus
pollen found in the Loch Etive site. These differences can be explained by the large catchment area of the loch which includes high ground, where it is proposed that extensive
Pinus
forest grew during much of the Holocene. The study demonstrates the practicality of using Scottish fjord sediments for Holocene pollen studies and potentially provides a link between terrestrial vegetation records and marine-based fossil records.