bluuebunny/crossref_metadata_2025 huggingface dataset:
Design and Evaluation of a Touch Activated Glove System for Upper Extremity Rehabilitation Studies
Authors: Johnson Wayne M. , Murphy Thomas , Brown Derrick , Riemann Bryan , Suttle Joshua , O’Canas Manuel
Published: March 2016

Upper extremity plyometric exercises show potential for shoulder injury prevention and rehabilitation. Plyometric exercises are physical activities in which muscles are extended and contracted in a rapid and repetitive manner. An example of a plyometric shoulder exercise consists of repeatedly throwing and catching a medicine ball into a trampoline system as quickly as possible. However, proper characterization of the efficacy of the exercise requires knowledge of ball contact events; specifically, the ball contact and release times. The objective of this work was to design and test a low cost touch activated glove system that could be used to determine contact events during upper extremity plyometric exercises. The sensor design consists of a neoprene frame over which layers of Velostat® film and copper fabric are arranged to create a pressure sensitive on-off switch. Individual sensors were constructed for digits II through IV and two for the upper palm area. Each sensor was attached to a nylon glove and wired to a terminal block, circuit board and battery pack situated on the back of the hand. A second nylon glove was used to cover and protect the sensors. Contact versus no contact sensor resistance was experimentally determined by measuring the sensors’ resistance when pressure was applied to various regions of the sensor contact area. This was used to anticipate the analogous contact verses no contact sensor voltage. The response time of the sensors plus measurement circuit was also determined by measuring the rise and fall time of the glove system due to contact events. Activated sensors produce a high voltage (> 3.0V) in the measurement circuit and indicate contact. The touch activated glove system was successfully used in a research study to quantify the intensity of overhand plyometric throwing and in another study to determine the biomechanical variables for the single arm seated shot put upper extremity functional performance test.
Ionic Polymer Metal Composites (IPMCs) Substrates as Real Time Sensing Systems to Study Biological Cells Adhesion, Traction and Migration
Authors: Saberi A. , Ashworth S. , Shahinpoor M.
Published: March 2016

In molecular cell biology, scientists employ many types of substrates over which to culture cells to study them. In many cases these substrates are made of rigid materials like glass or Mica. To mimic the in vivo substrates which are wet and soft and tissue like, they also grow cells on compliant substrates.

Depend on the subject of the research, many scientists utilize soft substrates made of gels to mimic the wet and soft tissues in biological systems and to study the migration of cells and related physical characteristics such as velocity, force, adhesion and traction and in general cell migration. Study of each of these subjects and parameters require complex procedures. For instance, time-lapse microscopy techniques are commonly employed that require advanced image processing techniques to track cells. During this time span, cells should be kept in an incubator to imitate their actual environments. One of the challenging physical parameters is the measurement of the force applied by a cell on its substrate in real time. Ionic polymer metal composites (IPMCs) are smart multi-functional materials with simultaneous sensing and actuation capabilities provide a unique system to dynamically monitor cell growth, differentiation, migration, adhesion and traction. Currently micro pillars made with polyacrylamide or polyethylene glycol gels and more recently polydimethylsiloxane (PDMS) microposts from microfabricated silicon masters only give information on cellular activities after the fact. IPMCs are capable or real time sensing of cell dynamics, adhesion and traction. This paper discusses some initial observations and the potential of such cell dynamic observations and tracking.
Ultrasound Phased Array for High Acoustic Attenuation Thick Composite Materials
Authors: Du Jikai , Rajhi Ali
Published: March 2016

Composite materials and structures are increasingly being applied in aerospace, marine, and wind power industries, as well as in commercial products. One main reason for the scientific interest in composite materials is their tailorable mechanical properties. However, because of the fiber-direction-dependent nature of its physical and mechanical properties, composite material’s property and failure behaviors are usually complex, typically involving various mechanisms depending on applications. Nondestructive testing plays a key role during composite fabrication and maintenance in service. Among the variety of nondestructive techniques available, ultrasound phased array technique has emerged as a promising new approach. Unlike a conventional ultrasound single element transducer, an ultrasound phased array sensor can control and focus acoustic energy to the desired directions and locations. This heightened flexibility and sensitivity is essential given complex shape of modern composite structures. Despite such promise, understanding and application of ultrasound phased array technique is limited due to the anisotropic nature of composite materials, as well as its high acoustic attenuation. Attenuation and velocity dispersion are the two major challenges to the ultrasound evaluation of composite structures; these two factors complicate the control of phased array ultrasound propagation both theoretically and experimentally. This is especially true for thick high attenuation carbon fiber or glass fiber composite materials that have been widely applied in aerospace and wind turbine industries.

In our study, ultrasound phased array technique was applied to increase the acoustic penetration power in high acoustic attenuation composite materials. First, ultrasound phased array signal in isotropic materials was studied to calibrate the probe parameters. Then for composite materials, the dependence of ultrasound field on the number of active elements, steering angles, beam focusing laws and on the characteristics of materials was analyzed and optimized through theoretical simulations and experimental evaluations. Results showed that the steering angles and the parameters of beam focusing laws might change the ultrasound beam intensity and uniformity, which had a significant influence on the sensitivity and resolution of the technique; the anisotropic properties of composite materials could distort the ultrasound beam, which made the calibration a necessary and important procedure during practical inspections. The influence of ultrasound frequency and beam angle were also quantitatively evaluated. The proposed research has the potential to apply ultrasound phased array technique to the detection of defects in composite materials and the evaluation of composite structural health. The study of the interaction between ultrasound and composite structures will open the window for the successful application of ultrasound phased array technique.
Numerical Modeling of Industrial Scale Transport Membrane Condenser Based Heat Exchangers for Flue Gas Waste Heat and Water Recovery
Authors: Soleimanikutanaei Soheil , Lin Cheng-Xian , Wang Dexin
Published: March 2016

In this paper, the effects of different working conditions on the performance of Transport Membrane Condenser (TMC) based heat exchangers are studied numerically. The effects of non-condensable gases on the condensation rate along with the number and distances of the TMC tubes in longitudinal and transversal directions were investigated. The numerical simulations have been conducted using the commercial software Ansys Fluent 14.5 and the condensation and heat and mass transfer are implemented using User Defined Functions (UDFs) in the numerical setup. The RNG two-equation turbulence model is used to handle heat, mass and momentum transfer across the TMC bundle tubes. The results are depicted in terms of volume fraction of water vapor and averaged outlet temperature of cooling water and flue gas. The results revealed that increase of the number of TMC tubes, when the inlet flow rate is constant, increases both the condensing surface area and average surface temperature which have opposite effects on the condensation rate, hence both of these parameters should be considered in industrial applications.
Coarse-Grained Molecular Dynamics Simulations of Sugar Transport Across Lactose Permease
Authors: Jewel Yead , Dutta Prashanta , Liu Jin
Published: March 2016

Sugar (one of the critical nutrition elements for all life forms) transport across the cell membranes play essential roles in a wide range of living organism. One of the most important active transport (against the sugar concentration) mechanisms is facilitated by the transmembrane transporter proteins, such as the Escherichia coli lactose permease (LacY) proteins. Active transport of sugar molecules with LacY proteins requires a proton gradient and a sequence of complicated protein conformational changes. However, the exact molecular mechanisms and the protein structural information involved in the transport process are largely unknown. All atom atomistic simulations are able to provide full details but are limited to relative small length and time scales due to the computational cost. The protein conformational changes during sugar transport across LacY are large scale structural reorganization and inaccessible to all atom simulations. In this work, we investigate the molecular mechanisms and conformational changes during sugar transport using coarse-grained molecular dynamics (CGMD) simulations. In our coarse-grained force field, we follow the procedures developed by Han et al. [1, 2], in which the protein model is united-atom based and each heavy atom together with the attached hydrogen atoms is represented by one site, then the protein force filed is coupled with the MARTINI [3] water and lipid force fields. This hybrid force field takes the advantage of the efficiency of MARTINI force field for the environment (water and lipid), while retaining the detailed conformational information for the proteins. Specifically, we develop the new force fields for interactions between sugar molecules and protein by matching the potential of mean force between all-atom and coarse-grained models. Then we validate our force field by comparing the potential of mean force for a glucose interaction with a carbohydrate binding protein from our new force field, with the results from all atom simulations. After validation, we implement the force field for sugar transport across LacY proteins. Through our simulations we are able to capture the formation/breakage of the important hydrogen bonds and salt bridges, which are crucial to the overall conformational changes of LacY.
Small-Scale Thermal Energy Harvester With Copper Foams and Thermal Energy Storage
Authors: Shrestha S. , Hays A. , Thapa S. , Wood D. , Bailey D. , Weiss L.
Published: March 2016

This article investigates the use of advanced, high porosity thermally conductive foams and a thermal energy storage (TES) device for small scale thermal energy harvesting. In final application, it may be employed in various real world situations that include existing systems like thermoelectric generators (TEGs) and thermal scavenging systems that provide power output from freely available thermal sources.

Experimental tests were conducted using various porosity metallic copper foams ranging from 85 % to 89 % porosity. Copper foams were selected to serve as the heat exchanger innards and examined for several key attributes. These included the ability of the foams to yield capillary action with working fluids like water or 3M™ HFE7200. Thermal energy absorption by the exchanger to the working fluid was also monitored. These results were compared to other exchangers based on capillary channel fabrication techniques as previously reported by the research team. Full characterization was based on operating temperature, measured thermal input, mass transfer rate, and heat transfer capability.

Preliminary investigation of a matching, small-scale TES unit designed to integrate with the heat exchanger and a future thermoelectric for energy harvesting application was also conducted. Thermal storage was accomplished via solid-liquid phase change of a paraffin wax within the TES device forming a so-called “thermal battery.” In a final design, the TES includes what is defined by thermodynamics as heat pipes. The integrations of several heat pipes, made of copper tubing and filled with working fluid, mounted vertically and immersed in the wax medium will transfer heat to the wax by means of thermal conductivity and phase transition. This represents a first of its kind in this small-scale, thermal harvesting application. The specific tests performed in this initial work included one TES unit filled with a paraffin wax medium and a second that contained several copper vertically placed tubes surrounded by the paraffin wax. The overall thermal conductivity of the phase change medium (wax) was investigated for both constructions as was the ability of each to absorb thermal energy directly.

Results indicated capillary action of the working fluid was possible via incorporation of copper foams within the heat exchanger. Maximum heat flux observed in exchanger tests was 0.27 kW/m2 given an operating temperature of 76.6 °C and 2.5W thermal input. Thermal storage tests indicated a maximum thermal capture rate of 0.91 W and phase change material thermal conductivity of 1.00 W/mK for the TES device constructed with copper tubing innards. This compared favorably to the baseline wax conductivity of approximately 0.32 W/mK. Future efforts will fully incorporate both the heat exchanger and matching TES device for a complete harvesting and thermal capture system. The ability of the exchanger to provide thermal energy for storage to the “thermal battery” will be monitored.
Development of a Virtual Platform to Evaluate the Performance of an Electrical Vehicle
Authors: Torres-Cruz Alberto , de Lange Dirk F. , Medellín-Castillo Hugo I.
Published: March 2016

Virtual simulations of electrical vehicle performance help to optimize vehicle design, by studying and predicting the effects of parameter variations on the vehicle performance, in order to find an optimum balance between the cost and benefit of design decisions. In this work, the development of a virtual platform to evaluate the performance of an electrical vehicle is presented and applied to the study of public urban transportation. The aim is to analyze the requirements and optimize specifications for a light weight, energy efficient, autonomous vehicle without energy supply along the trajectory, except in the stations.

Virtual platforms for vehicle performance have been developed before, and in many cases characteristic velocity profiles are used as a reference, according to the traffic environment in which the vehicle will operate. Vehicle analysis and design is focused on feasibility of the vehicle to be able to follow the prescribed velocity profile.

In the present study, the evaluation is instead based on the cost/benefit relationship for an urban transport vehicle on traffic-free trajectories, enabling to adjust and optimize the velocity profiles in order to optimize the energy use while minimizing travel time. Therefore, the virtual platform is focused on the calculation of the net energy usage, the travel time and the system cost corresponding to an electrical vehicle with different battery and ultra-capacitor energy storage capacities, regeneration and storage of brake energy and an automatic governor for autonomous vehicle control.

The influence of design parameters, such as the installed motor power, energy storage capacity, vehicle weight, passenger load and vehicle control strategy on the time schedule and energy efficiency is studied. However, the effort does not aim for a straight forward optimization of efficiency or minimization of travel time. In fact, energy optimization often conflicts with the travel time optimization. Therefore, both are analyzed simultaneously in order to assist in the search for an optimum compromise. In addition, the results are interpreted in terms of the overall obtained benefits of travel time reduction or optimization of the energy use, in contrast with the corresponding increment of the investment cost of the vehicle related to the implementation of the studied parameter variation. Specific trajectory profiles, including height profiles can be defined for optimization of the vehicle system for application in specific locations with specific geographic conditions.
Experimental Investigation on the Effect of Zirconium on Corrosion Resistance of Ceria Nanoparticles
Authors: John Joseph , Vandana Sajith
Published: March 2016

Corrosion is the gradual deterioration of materials by chemical reaction with their environment, leading to the formation of less desirable material, which lacks in functionalities of the system. Corrosion resistant coatings have being an active subject of research since a while. Aiming at the replacement of toxic anti-corrosion pigments in organic coating industries, in the last two decades several environmentally friendly pigments have been studied, which involves passivating compounds such as molybdates, permanganates, vanadates, and tungstates. Cerium compounds are attaining more attention due to their potential as corrosion inhibitors. The present work aims at the experimental investigation on the effect of zirconium on corrosion resistance of ceria nanoparticles, in epoxy resins. Ceria and cerium zirconium mixed oxide nanoparticles was prepared by co-precipitation method. Ceria and cerium zirconium mixed oxide nanoparticles were dispersed in epoxy resin and the composites were spin coated on mild steel specimens. Surface studies was done using AFM and electrochemical studies were done one the coated surfaces using Zahnier IM6 modular electrochemical workstation. The Impedance spectra and surface structure studies showed highly improved corrosion resistance for ceria and cerium zirconium mixed oxide nanoparticles added epoxy primers as compared to unmodified epoxy resin primer. UV resistance of the coatings were found to be improved for ceria and cerium zirconium mixed oxide nanoparticles based coatings.
Analysis and Comparison of Biochar From Pilot Scale Downdraft Gasifier
Authors: Sharma Tejasvi , Shi Yunye , Zang Guiyan , Ratner Albert
Published: March 2016

Gasification is incomplete combustion of solid fuel that results in the production of vapor, often referred to as syngas or producer gas, char, and tar. When this process is applied to biomass, the resulting char, referred to as biochar, is produced and has been shown to enhance soil fertility and crop growth. As part of a broader effort, this work examines how the gasification process impacts the biochar generated through downdraft gasification. In contrast to previous publications, which only focused on the syngas compositions, this research paper expands the analysis to the composition of the biochar produced in the gasification systems.

In a large-scale gasifier, corn grains at about a 15% moisture level are inserted into a pilot scale downdraft gasifier from the top. In this system, both air and fuel move in the same direction. The air entering the setup is controlled using a damper. Corn grains entering the gasifier pass through a drying zone where the moisture content in it is removed. The dry corn then passes through a combustion and pyrolysis zone, followed by a reduction zone. The high temperature present at the bottom in the reduction zone cracks any tar present in the syngas produced. This syngas exits from the bottom of the gasifier. The char produced has a residence time from half an hour to several hours. About 20% of the fuel that’s inserted in the gasifier is converted to biochar.

An ultimate and proximate chemical composition analysis, BET porosity analysis, and an SEM image analysis were carried out on the biochar produced from this system. From the SEM analysis, a surface area of 2.38 m2/g was obtained. From the ultimate and proximate analysis, it was observed that the biochar had higher carbon content and a lack of volatile components compared to other reported biochars and levels similar to activated carbon. From the BET porosity analysis, both small scale and large-scale pores were observed but quantified comparison with other biochar is still on going. Porosity is known to be an important factor in biochar effectiveness as a soil amendment.
A Stochastic Asset Life Prediction Method for Large Fleet Datasets in Big Data Environment
Authors: Bagheri Behrad , Siegel David , Zhao Wenyu , Lee Jay
Published: March 2016

Preventing catastrophic failures is the most important task of prognostics and health management approaches in industry where Remaining Useful Life (RUL) prediction plays a significant role to schedule required preventive actions. Regarding recent advances and trends in data analysis and in Big Data environment, industries with such foreseeing approach are able to maintain their fleet of assets more efficiently with higher assurance. To address this requirement, several physics-based and data-driven methods have been developed to predict the remaining useful life of various engineering systems. In current paper, we present a simple, yet accurate stochastic method for data-driven RUL prediction of complex engineering system. The approach is constructed based on selecting the most significant parameters from raw data by using the improved distance evaluation method as feature selection algorithms. Subsequently, the health value of units is assessed by logistic regression and the assessment output is used in a Monte Carlo simulation to estimate the remaining useful life of the desired system. During Monte Carlo iterations, several features are extracted to help filtering less accurate estimations and improve the overall prediction accuracy. The proposed algorithm is validated in two ways. First of all, the accuracy of RUL prediction is measured by applying the method to 2008 PHM data challenge gas-turbine dataset. Subsequently, gradual changes in RUL prediction of a particular test unit are measured to verify the behavior of the algorithm upon availability of additional historical data.
Development of a Network Infrastructure for Heterogeneous Robot and Control Systems Interactions
Authors: Reid Christopher J. , Samanta Biswanath , Kadlec Christopher
Published: March 2016

The use of robots in complex tasks such as search and rescue operations is becoming more and more common. These robots often work independently with no cooperation with other robots or control software, and are very limited in their ability to perform dynamic tasks and interact with both humans and other robots. To this end, a system must be developed to facilitate the cooperation of heterogeneous robots to complete complex tasks. To model and study human-robot and robot-robot interactions in a multi-system environment, a robust network infrastructure must be implemented to support the broad nature of these studies. The work presented here details the creation of a cloud-based infrastructure designed to support the introduction and implementation of multiple heterogeneous robots to the environment utilizing the Robot Operating System (ROS). Implemented robots include both ground-based (e.g. Turtlebot) and air-based (e.g Parrot ARDrone2.0) systems. Additional hardware is also implemented, such as embedded vision systems, host computers to support virtual machines for software implementation, and machines with graphics processing units (GPUs) for additional computational resources. Control software for the robots is implemented in the system with complexities ranging from simple teleoperation to skeletal tracking and neural network simulators. A robust integration of multiple heterogeneous components, including both hardware and software, is achieved.
Roll-Yaw Coupled Vibration of the Rotor System With Breathing Crack and Unbalance Mass
Authors: Zhao J. , DeSmidt H. A. , Peng M. , Yao W.
Published: March 2016

This paper develops a new finite element rotor model with consideration of the coupling effect of rolling and yawing motion. The crack model is built using released strain energy concept in fracture mechanics. The nonlinear breathing behavior of cracks on the rotor shaft is simulated through Zero Stress Intensity Factor (SIF) method. The vibration responses of rotor system are solved by Newmark Integration method for both nominal and damaged system. With the yawing motion, the additional force will be induced for beam element and center disk. Incorporated with breathing crack model, the breathing behavior of crack is comprehensively studied in terms of the rolling rate, yawing rate and yawing acceleration. The clear understanding of crack breathing behavior is beneficial for the damage detection and health monitoring of the rotor system.
Mechanical Design and Control Calibration for an Interactive Animatronic System
Authors: Burns Brian , Samanta Biswanath
Published: March 2016

Animatronic figures provide key show effects in the entertainment and theme park industry by simulating life-like animations and sounds. There is a need for interactive, autonomous animatronic systems to create engaging and compelling experiences for the guests. The animatronic figures must identify the guests and recognize their status in dynamic interactions for enhanced acceptance and effectiveness as socially interactive agents, in the general framework of human-robot interactions. The design and implementation of an interactive, autonomous animatronic system in form of a tabletop dragon and the comparisons of guest responses in its passive and interactive modes are presented in this work. The purpose of this research is to create a platform that may be used to validate autonomous, interactive behaviors in animatronics, utilizing both quantitative and qualitative analysis methods of guest response. The dragon capabilities include a four degrees-of-freedom head, moving wings, tail, jaw, blinking eyes and sound effects. Human identification, using a depth camera (Carmine from PrimeSense), an open-source middleware (NITE from OpenNI), Java-based Processing and an Arduino microcontroller, has been implemented into the system in order to track a guest or guests, within the field of view of the camera. The details of design and fabrication of the dragon model, algorithm development for interactive autonomous behavior using a vision system, the experimental setup and implementation results under different conditions are presented.
An Integrated Procedure for Computer Simulation of Dynamics of Multibody Molecular Structures in Polymers and Biopolymers
Authors: Duan Shanzhong (Shawn)
Published: March 2016

Though computational molecular dynamics is an effective tool for nano-scale phenomenon analysis, computational costs associated with its computer simulation are extremely high. There are two major computational steps associated with computer simulation of dynamics of molecular structures. They are calculation of interatomic forces and formation and solution of the equations of motion. Currently, these two computational steps are treated separately in most commonly-used methods. For example, Fast Multipole Method (FMM) and Cell Multipole Method (CMM) have been used for calculation of interatomic forces, and Cartesian Coordinate Method (CCM) and Internal Coordinate Molecular Dynamics Method (ICMD) have been created for the formation and solution of equations of motion of an atomistic molecular system.

In this paper, a new procedure is presented through a proper integration between multibody molecular algorithms (MMA) and fast multipole methods to improve computational efficiency for computer simulation of the dynamical behaviors of multibody molecular structures in polymers and biopolymers. For the computational costs associated with interatomic forces, a fast multipole method is used to calculate the interatomic forces due to the potentials. For the computational costs associated with formation and solution of equations of motion, a multibody molecular algorithm developed by the author in his previous work will be utilized to integrate with fast multipole methods. The algorithm significantly improves computational efficiency when comparing with its counterpart procedures.

The fast multipole method begins by scaling all atoms into a box with coordinate ranges to ensure numerical stability of subsequent operations. The parent box is then divided into half in the direction of each Cartesian axis and each child box is then subdivided to form a computational family tree. The flow of calculations is carried out along the tree structure with five passes. The fast multipole method has been improved and modified to achieve better effectiveness and higher efficiency since it was created.

The multibody molecular algorithm starts with numbering subsets, forming bond graph, and developing three computing passes along the tree structure of an atomistic molecular system. Computing data flows in the fast multipole method and the multibody molecular algorithm will properly line up with the parent-child recursive relationship along the configuration of the tree structure due to linear recursive natures of both fast multipole method and multibody molecular algorithm. Then the time spent on the recursive simulation passes in the fast multipole method for computing forces may overlap with the time spent on the three recursive computational passes in the multibody molecular algorithm for forming and solving equations of motion.
Ejector Profile Modelling for Heat-Driven Ejector Refrigeration System Without Involving Shock
Authors: Abuan Binoe E. , Berana Menandro S.
Published: March 2016

Heat-driven ejector refrigeration system is one of the fastest emerging technologies in cooling applications for years. This is due to the fact that it can harness cooling capacity from waste heat sources at above 80 °C. Low coefficient of performance (compared to commercial vapor compression systems) is the major disadvantage of the said system, and thus it became a topic of research studies in the field of cooling. The work required by the compressor in a vapor compression cycle (VCC) can be eliminated by using waste heat from any available heat source. Although a relatively lower COP was obtained, the savings using the ejector refrigeration system can cover all the disadvantages and proved that this system can be actually helpful if implemented in the real working systems with waste heat.

In this study, a mathematical model for determining ejector parameters and performance was developed and applied to a system where shock was tried to be avoided. The model was coded into a computer program to allow easier computation of the ejector geometric and thermo-fluid dynamic parameters with varying input data such as the refrigerant to be used, evaporator and condensing temperatures, entrainment ratio, and velocity of the fluid flows. An ejector refrigeration system using ammonia, propane, R22, R134a, R1234yf, and R245fa as refrigerants was simulated using the said model. A boiler or generator temperature of 90 °C, a condenser temperature of 40 °C, and a refrigerating capacity of 35kW were maintained for all the refrigerants; however, the evaporator temperature was varied within the range of −10 °C to 10 °C, depending on the behavior of the system. A combination of a short straight section and then a converging-diverging profile was used for the combined mixing section and diffuser to smoothly decelerate the fully mixed supersonic flow exiting the short mixing section and thereby avoid shock waves in the section. The resulting parameters including the ejector dimensions, pressure and Mach number were determined along the length of the ejector. For all the simulation runs, the fluids respond as expected and the expansion energy was utilized from the high pressure side of the ejector as shown in the trend of pressure along the length of the ejector. Ejector size varies a little for different refrigerants; the calculated range of length is from 0.14 m to 0.36 m — this range shows the compactness of the resulting ejectors.

The results show that a VCC refrigeration system can be replaced by a heat-driven ejector refrigeration system with the ejector that was designed from the simulations. Since the two systems are designed to have the same refrigerating capacity and working temperatures, it can be projected that savings can be made by using the ejector system. The compactness of the ejector produced in the simulations show a good potential for this kind of refrigerating system to be manufactured and mass produced.
40-MHz Micromachined PMN-PT Composite Ultrasound Array for Medical Imaging
Authors: Li Sibo , Huang Wenbin , Chang Wei-Yi , Jiang Xiaoning
Published: March 2016

Ultrasonography is well known as a relatively low cost and non-invasive modality for real-time imaging. In recent years, various high frequency array transducers have been developed and used for ophthalmology, dermatology, and small animal studies. This paper reports the development of a 48-element 40-MHz ultrasonic array using micromachined lead magnesium niobate-lead titanate (PMN-PT) single crystal 1–3 composite material. Array elements with a pitch of 100-micron were interconnected via a customized flexible circuit. Pulse-echo test showed an average center frequency of 40 MHz and a −6 dB fractional bandwidth of 52%. The −20 dB pulse length was evaluated as 120 ns. The electrical and acoustical separation showed the crosstalk less than - 24 dB. An image of a steel wire target phantom was acquired by stacking multiple A-lines. The results demonstrate resolutions exceeding 70 μm axially and 800 μm laterally. Those results imply the great potential of the developed array transducer for the high frequency medical imaging.
Application of Inverse Analysis to Determine the Parameters of the Weighted Multi Point Source Model for the Prediction of Heat Flux From Flames
Authors: Miguel R. B. , França F. H. R. , Machado I. M. , Pereira F. M. , Pagot P. R.
Published: March 2016

Thermal radiation is responsible for a substantial portion of the heat transfer from a flame. Radiative characteristics of jet fires are usually expressed through the use of the fraction of heat radiated. Detailed flame simulations provide useful information but may be prohibitive for practical applications due to the significant computational resources that are required. The weighted-multi-point-source model uses point sources with different weights to simulate the contribution of each portion of the flame. This method can give good predictions of the radiant heat flux both in the near and far fields. While previous studies used the trial-and-error approach to determine the weights of the sources, this paper proposes a method to obtain the weight of each source by inverse analysis. In the analysis, the experimental measured radiation heat flux distribution is the input data, while the weights of the sources and the fraction of heat radiated are the sought parameters. The inverse problem is formulated as an optimization problem, which is solved by the generalized extremal optimization. As will be shown in the paper, the inverse method is capable of recovering the weights of the sources that lead to results with more accuracy than the single source model or the multiple sources model with the commonly employed linear variation in the weights.
Generalized Airloads Prediction for Bluff Bodies Transported as Slung Loads
Authors: Motahari Nicholas , Hiremath Nandeesh , Shukla Dhwanil , Liberi Brandon , Thorell Nikolaus , Komerath Narayanan
Published: March 2016

Objects of arbitrary shapes have to be carried as slung loads under aircraft, particularly rotorcraft. The flight speed is limited by the possibility of slung loads going into divergent oscillations. In 2014 we presented a testing-based approach to predict the safe flight speed, applicable to bluff bodies of arbitrary shape. Since then, an extensive variety of bluff-body shapes has been tested, and we venture further towards generalized airload prediction, required for generalized divergence speed prediction. Extending recent work, the Continuous Rotation method is applied to obtain aerodynamic loads on generic shapes: a circular cylinder and a rectangular prism, both with aspect ratio varied systematically. The genesis of the side force on the yawed cylinder, and the differences between rough and smooth cylinders, have been derived from comparisons between experiments and diagnostic computations with an unsteady Navier-Stokes solver. Interpolating Fourier coefficients of the azimuthal load variation appears to be viable to generalize loads on cylinders of varying aspect ratio for both the generic shapes.
Method for Determining the Efficiency of Generation of a Genset Coupled to a Biomass Gasification Process
Authors: Páez Salgado Roberto José , Marzola Atencia Luisa Fernanda , Mendoza Fandiño Jorge Mario , Ávila Gómez Adrián Enrique , Arango Meneses Juan Fernando
Published: March 2016

This research is based on obtaining a mathematical model to determine the efficiency of generating a generator coupled to a biomass gasification process. To do this, it is initially simulated internal combustion engine at the Aspen hysys® licensed software, in order to obtain the shaft work and a representative model of the generation efficiency of the motor; according to the characteristics of the power cycle and product gas from the gasification of agricultural biomass prevailing in the Department of Córdoba – Colombia: Cotton waste (Gossypium hirsutum), Rice husk (Oryza sativa), Sesame stalk (Sesamum indicum), Corn cob (Zea mays) and Coconut fiber (Cocos nucifera).

Subsequently, the generator efficiency is evaluated by the electric power generation simulation phase in the Simulink Toolbox of the MATLAB® software.

The deterministic mathematical models resulting from the simulations above are adjusted by statistical techniques to experimental data and a regression model that assesses the overall system efficiency is obtained. Such efficiencies range from 16 to 20%. Therefore it is concluded that the use of representative crops biomass product’s calorific values in the Department of Córdoba -Colombia, are profitable for electric power generation.

On the other hand, it is important to note that experimental data’s reliable and monitored way acquisition was performed through the SCADA developing; it allowed real time process variables’ intervention presentation.
Electrodeposition of Long Silver Nanowires in Highly Ordered Polymer-Based Template
Authors: Jia Zheng , Choi Junseo , Park Sunggook
Published: March 2016

Template synthesis of silver nanowires is studied in this paper. Unlike previous studies, highly ordered polymer-based template fabricated by nanoimprinting lithography was used instead of porous polycarbonate (PC) and anodic aluminum oxide (AAO) templates. This new template combines the advantages of the traditional templates and overcomes their drawbacks at the same time. Electrodeposition was carried out under different overpotential and time periods. Long single silver nanowires were found in the templates. The average length of the nanowires was much shorter than the length of the template, which can be explained by difficulty of plating solution diffusion. Wettability of the template and how to increase channel filling rate were also discussed in this paper.
On Local and Global Species Conservation Errors for Nonlinear Ecological Models and Chemical Reacting Flows
Authors: Mudunuru M. K. , Shabouei M. , Nakshatrala K. B.
Published: March 2016

Advection-controlled and diffusion-controlled oscillatory chemical reactions appear in various areas of life sciences, hydrogeological systems, and contaminant transport. In this conference paper, we analyze whether the existing numerical formulations and commercial packages provide physically meaningful values for concentration of the chemical species for two popular oscillatory chemical kinetic schemes. The first one corresponds to the chlorine dioxide-iodine-malonic acid reaction while the second one is a simplified version of Belousov-Zhabotinsky reaction of a non-linear chemical oscillator. The governing equations for species balance are presented based on the theory of interacting continua. This results in a set of coupled non-linear partial differential equations. Obtaining analytical solutions is not practically viable. Moreover, it is well-known in literature that if the local dynamics becomes complex, the range of possible dynamic behavior in the presence of diffusion and advection becomes practically unlimited. We resort to numerical solutions, which are obtained using two popular stabilized formulations: Streamline Upwind/Petrov Galerkin and Galerkin/Least Squares. In order to make the computational analysis tractable, an estimate on the range of system-dependent parameters is obtained based on model reduction performed on the strong-form of the governing equations. Finally, we quantify the errors in satisfying the local and global species balance for various realistic benchmark problems. Through these representative numerical examples, we shall demonstrate the need and importance of developing locally conservative non-negative numerical formulations for chaotic and oscillatory chemically reacting systems.
GHz Heterogeneous Phononic Crystal Slab Resonators
Authors: Dehghannasiri Razi , Pourabolghasem Reza , Eftekhar Ali Asghar , Adibi Ali
Published: March 2016

In this paper, we present a new design for waveguide-based phononic crystal (PnC) resonators in pillar-based piezoelectric membranes at the GHz frequency range based on mode-gap waveguide termination. The mode confinement in these resonators is achieved by a smooth transition from a phononic waveguide to another phononic waveguide that does not support (and therefore reflects) the guided modes of the first waveguide over a certain frequency range. These resonators can be utilized for applications including wireless communications and sensing [1, 2] where high-Q and high-frequency resonators are highly desirable.
Carbon Cone Electrodes for Selection, Manipulation and Lysis of Single Cells
Authors: Natu Rucha , Islam Monsur , Martinez-Duarte Rodrigo
Published: March 2016

Here we present initial experiments towards an integrated platform for single cell selection, manipulation and lysis. The premise is that an array of polarized conical carbon electrodes can be dipped in a cell culture, trap cells of interest using dielectrophoresis and transport them to specific locations where they can be lyzed electrically. We aim at developing an automated tool to extract intracellular components from targeted particles over specific locations, i.e., a DNA microarray or other functionalized spots. What we contribute in this work is modeling of the electric field and its gradient around carbon cones, as well as initial cone fabrication results. To the best of our knowledge, both the fabrication of conical glassy carbon electrodes and the general concept of the proposed platform are novel. Ongoing work is on demonstrating cell trapping and lysis using these conical electrodes by only varying the magnitude and frequency of their polarizing AC signal.
Micro-Computed Tomography to Finite Element Analysis of In Vivo Biodegradable Magnesium-Alloy Screw and Surrounding Bone in Rabbit Femurs
Authors: Williams Adrienne F. O. , McCullough Matthew B. A.
Published: March 2016

Magnesium (Mg) and its alloys are attractive orthopedic biomaterials because of their degradability and mechanical properties, which are similar to bone’s. Characterizing the mechanical changes and interactions of these promising degradable biomaterials and the host environment (bone) is essential to their success in orthopedic devices.

The objective of this study was to develop a protocol to evaluate in vivo biodegradable Mg-alloy screws and surrounding new and cancellous bone in rabbit femurs over time, using high resolution micro-computed tomography (micro-CT) images and the finite element method.

Micro-CT was used to visually evaluate bone remodeling and degradation of Mg-alloy screws that were implanted in rabbit femoral condyles for 2, 4, 12, 24, 36 and 52 weeks. Over time, the degradation product around the device and the remainder of the intact core was observed. Scans were segmented into bone, degradation/corrosion products and non-degraded device, then reconstructed into 3D volumes. These volumes were meshed and assigned material properties based on CT data. The meshed volumes were exported to finite element software and analyzed in a virtual environment.

Several foundational observations were made about animal modeling of in vivo degrading magnesium devices with a micro-CT to FEA protocol.
Conjugate Analysis of Thin Film Heat Spreaders to Reduce Temperature at Hot Spots
Authors: Reddy Sohail R. , Abdoli Abas , Dulikravich George S. , Jha Rajesh
Published: March 2016

The effects of thin film coating on maximum temperature of integrated electric circuits are investigated. A fully three-dimensional conjugate heat transfer analysis was performed to investigate the effects of thin film material and thickness on the temperature of a hot spot. Two different materials, diamond and graphene nano-platelets were simulated as materials for thin films. The thin film heat spreaders were applied to the top wall of the three optimized arrays of micro pin-fins having circular, airfoil and convex cross sections. The electronic chip with a 4 × 3 mm footprint featured a 0.5 × 0.5 mm hot spot located on the top wall which was exposed to a uniform high-level background heat flux. The effective area of coverage of the thin films was also investigated computationally. It was found that thin film heat spreaders significantly reduce the hot spot temperature, allowing for increased thermal loads and therefore increased performance. Furthermore, it was found that thickness of the thin film heat spreader does not have to be greater than a few tens of microns.
Stress Propagation in a Hierarchical Energy Dissipating Composite Based on NPSL
Authors: Xie Baozhi , Liu Ling , Zhang Lin
Published: March 2016

Developing advanced energy absorption materials and structures is of both fundamental scientific interest and great technological importance. In this study, we investigate the energy absorption capability of a new composite material under impact loading by using ANSYS and LS-DYNA. This new composite is composed of polymeric matrix and Nanoporous Particle Suspended Liquid (NPSL) fillers. NPSL fillers are embedded in a polymeric matrix to form a composite protective layer on a rigid substrate. A numerical method based on the PLANE162 finite element scheme has been developed specifically to investigate the effects of the various material parameters on the energy absorption efficiency provided by the NPSL-based composite. Among these parameters, activation pressure is at the NPSL level, while filler diameter and spacing are at the composite level. All these parameters show pronounced effects on the mechanical properties of the composite, and they can be engineered by fine-tuning the processing techniques.