bluuebunny/crossref_metadata_2025 huggingface dataset:
Micro-Scale Thermal Sensor Manufacturing and Measurement of Temperature Uniformity on Wafer Surface
Authors: Kim Jun Young , Jang Kyung Min , Yang Hong Cheon , Kim Kwang-Sun
Published: April 2014

In this research, uniformity of temperature on wafer in fine scale was investigated. A measurement system has been developed, and a sensor as thin-film thermocouple was fabricated using a lift-off process. To generate EMF voltage by Seebeck effect, Chromel and Alumel materials were used for the thermocouple. The system obtains the micro scale temperature from multi-points on the surface of the wafer and then precisely analyzes thermal distribution. A numerical analysis was performed to compare to the measurement method. The experimental results and the analysis shows the system can be used for thermal measurement in a micro scale.
Computation of Common Normal Between Wheel and Rail Surface via Linearized Track
Authors: Fallahi Behrooz , Perla Arjun Kumar , Corn Kyle
Published: April 2014

Computation of contact points between the wheel and rail is a fundamental problem in dynamic simulation of trains. To compute these contact points, one needs to locate common normals first. The objective of this study is to develop an efficient method to compute common normals between wheel and rail surface. This is done by devising a method to compute an estimate of location of common normals and then using them as the initial guess to compute them. To generate an estimate of the location of common normal, a local approximation of the rail is constructed. To achieve this, the intersection of the vertical mid-plane of the wheelset with a track curve of a rail is computed and the tangent line at this point is generated. The rail profile is place on the tangent line and is swept along it. The resulting rail is called linearized rail in this study. It is shown that the four nonlinear equations governing the location of the common normal can be reduced to one equation in one unknown. This equation is referred to as reduced equation. A bracketing algorithm is added to identify the intervals within which this reduced equation changes sign. These intervals contain the zero of the reduced function. The zeros of the reduced equation are used to compute an estimate of the common normals. These estimates are used as an initial guess for a Newton iterate to accurately locate all common normals. It is observed that the CPU time to compute all common normals is of the order of mili-second.
Acoustic and Elastic Cloaking Using Non-Singular Transformation
Authors: Tehranian Aref , Nemat-Nasser Sia
Published: April 2014

Non-singular transformation is developed to achieve approximate acoustic and elastic cloaking. In the literature, perfect cloaking is realized under the condition of mapping cloak inner boundary to a single point, which gives rise to the development of unconventional metamaterials. Such cloaks introduce serious challenges in terms of materials design and fabrication. This paper studies the transformation functions that map the inner boundary of a 2D acoustic or elastic cloak (in physical space) to a region with small but finite dimension (in mathematical space). The goal is to find an optimized transformation that considers the limitations on mass density anisotropy, and elastic anisotropy of realizable metamaterials. It should be noted that the proposed cloak is not perfect and scatters minimal portion of the incident wave. However, it provides a realistic path towards the design and fabrication of an acoustic cloak for pressure waves, and elastic cloak for general stress waves.
Tensile Properties Evaluation of Chemically Treated/Untreated Single Sugarcane Fiber
Authors: Hossain Mohammad K. , Karim Mohammad R. , Chowdhury Mahmudur R. , Imam Muhammad A. , Hosur Mahesh , Jeelani Shaik , Farag Ramsis
Published: April 2014

Natural fiber as a reinforcing constituent can play a dominant role in the field of fiber reinforced polymer composites (FRPC) due to its eco-friendliness, renewability, abundance in nature, co2-neutrality, flexibility, low density, and low cost. Hence, sugarcane fiber can be a potential candidate to replace the synthetic FRPC. The objective of this study is to evaluate the effect of chemical treatment on the tensile properties of single sugarcane fiber. Sugarcane collected from the local market was cut into some specific length and fibers were extracted from the juicy section. These fibers were then dried in an oven to remove the moisture. Surface modification was accomplished by performing alkali treatment and neutralizing by acetic acid solution. The fiber was then rinsed with water and dried at 80°C for about twenty four hours using an oven. Untreated and treated fibers were characterized using tensile testing according to the ASTM D 3822-01 standard. Optical microscopy (OM) was employed to measure the diameter of the fiber and scanning electron microscopy (SEM) was used to evaluate the fracture morphology of failed samples. Tensile tests were carried out on the span length of 25 mm of the single fiber. The resultant data showed that maximum improvement in the tensile strength and modulus was observed to be 87% and 29%, respectively, compared to those of untreated ones due to chemical treatments using 5% NaOH solution and 2% acetic acid solution, respectively. Strain to maximum strength was enhanced by about 16% compared to that of the untreated one. A small initial weight loss was observed in the temperature ranging from 25 to 150 °C due to the evaporation of water. However, untreated fiber started to decompose at around 200 °C while treated fiber started to become decomposed at around 250°C. It might be due to the removal of non-cellulosic substances including hemicellulose, lignin, and pectin as a result of the chemical treatment. Fracture morphology of the treated fiber revealed rougher fracture surfaces compared to untreated fiber surfaces. This is an indication of more energy absorption by the treated fibers during the tensile loading.
Laser-Assisted on Demand Growth of Semiconducting Nanowires
Authors: Ryu Sang-gil , Hwang David J. , Kim Eunpa , Yoo Jae-hyuck , Grigoropoulos Costas P.
Published: April 2014

We present laser-assisted direct synthesis of nanowires with site-, composition-, and shape-selectivity on a single substrate by employing a spatially confined laser heat source. Laser-assisted nanowire growth based on vapor-liquid-solid mechanism is conveniently studied with multiple growth parameters such as temperature, time, and illumination direction. On-demand direct integration of silicon and germanium nanowires are demonstrated in a hetero-array configuration by simply switching the reactant gases as the growth of nanowires is limited within the heat-affected zone induced by the laser. Since laser-induced local temperature field is able to drive the individual growth, each germanium nanowire is successfully synthesized with distinctively different geometric features from cylindrical to hexagonal pyramid shape. By regularly patterning gold catalysts prepared by electron beam lithography on Si(111), especially, we accomplished site- and shape-selective direct integration of germanium nanowires on a single substrate in vertical architecture. Considering that blanket furnace heating only produce nanowires with uniform size and shape, therefore, our work shows a route toward the facile fabrication of multifunctional nanowire based devices.
‘Acoustic Fiber’ Aluminum-Clad Steel Cable for Communication and Power Transmission
Authors: LaDouce James A. , Scarton Henry A. , Wilt Kyle R. , Das Pankaj K. , Saulnier Gary J.
Published: April 2014

An aluminum-clad steel wire is used to transmit power acoustically. Analogous to optical fiber cable consisting of a core and a cladding layer selected for total internal reflection due to the difference in refractive index between the two, an acoustic fiber cable is constructed by using aluminum-clad steel wire having the property that the bulk longitudinal acoustic wave speed within aluminum is higher than within the steel core by about 8% such that ultrasonic longitudinal waves are trapped in the steel core and the acoustic waves propagate to great range. Results using a 5.9 mm aluminum-clad steel wire 28.7 m long with 0.45 mm wall thickness show successful acoustic transmission in air in the frequency range 20 Hz to 1.5 MHz, with maximum power transmission efficiency 26% for frequencies near 75 kHz and 12% for frequencies near 215 kHz.
Study on Heat Transfer From Hot Water to Cold Air With Evaporation
Authors: Yamaji Tatsuya , Hirota Tatsuya , Koizumi Yasuo , Murase Michio
Published: April 2014

Evaporation heat transfer from hot water flow to cold air flow in a horizontal duct was examined. Experiments were performed for turbulent condition. The test flow channel was rectangular. The width, height and length were 40 mm, 20 mm and 1,000mm. The length of heat transfer surface was 140 mm. In experiments, hot water was in the range of 40 °C ∼ 60 °C. Cold air was approximately at 20 °C. The air velocity was varied from 1.61 m/s ∼ 10.5 m/s. Heat transfer rate from hot water flow to cold air flow became large with an increase in air velocity. The higher the water temperature was, the larger the heat transfer rate was. When total heat flux from water to air flow was divided into two terms; the evaporation term and the forced flow convection term, the evaporation term dominate main part and that was about 60 ∼ 80 % of the total heat flux. Water surface temperature drop from bulk water temperature was confirmed. However, the temperature drop was less than 5 °C. The surface temperature drop had little effect on the evaporation heat flux and the convection heat flux. The measured evaporation heat flux was lower than the value predicted with the mass transfer correlation that was developed through analogy between heat transfer and mass transfer. The measured convection heat flux was higher, approximately twice, than the value that was calculated with the correlation for turbulent flow heat transfer probably because of bottom heating. The method to predict the heat transfer from the hot water flow to the cold air flow with the evaporation was developed by modifying the turbulent flow mass transfer correlation and the turbulent forced convection heat transfer correlation. Good results were obtained.
A Numerical Study of Unsteady Mixed Convection in a Square Cavity: Transition From Laminar to Turbulent Flow
Authors: Akyuzlu K. M.
Published: April 2014

A study was conducted to simulate the circulation patterns and heat transfer characteristics of flows in a square cavity during transition from laminar to turbulent mixed convection conditions using numerical techniques. The cavity under study is assumed to be filled with a compressible fluid. The bottom of the cavity is insulated and stationary where as the top of the cavity (the lid) is assumed to be stationary initially and then pulled at constant speed for times greater than zero. The vertical walls of the cavity are kept at constant but unequal temperatures. A two-dimensional, physics based mathematical model is adopted to predict the momentum and heat transfer inside this rectangular cavity. A standard two equation turbulence model is used to model the turbulent flow inside the enclosure and the compressibility of the working fluid is represented by an ideal gas relation. The numerical solution techniques adopted in this study is a hybrid one (implicit-explicit) where the conservation equations for the velocity, temperature, and pressure are solved using an implicit technique (Coupled Modified Strongly Implicit Procedure -CMSIP) whereas the equations for the standard K-ε turbulence model are solved using an explicit (MacCormack) technique. In both techniques, a second order accurate finite difference technique is used to discretize the governing equations. Then numerical experiments were carried out to simulate the unsteady flow and heat transfer characteristics of mixed convection flow inside a square cavity filled with air (Pr = 0.72) for different Richardson numbers in the range of 0.00868–0.03470; corresponding to Reynolds numbers ranging from 2000 to 4000, respectively, when the Rayleigh number was kept constant at 105. Vertical and horizontal temperature and velocity profiles were generated while the flow goes through transition from laminar to turbulent. Changes in wall heat flux were calculated and average Nusselt numbers were determined for each parametric study.
Instantaneous Aerodynamic Load Calculations in Rotating Airfoils From Time Resolved PIV Measurements at Low Reynolds Number
Authors: Villegas Arturo , Diez F. Javier
Published: April 2014

The time-resolved evolution of the instantaneous pressure fields and aerodynamic loads are obtained for rotating airfoils. This method allows evaluating the fluctuations in the instantaneous aerodynamic loads which cannot be evaluated with averaging methods. It also has the ability of capturing high temporal variations such as vortex shedding in the wake of the rotating blade. Briefly, this method obtains the velocity field from time-resolved particle image velocimetry TR-PIV. This is used to calculate the pressure field around the turbine from the Poisson pressure equation. Then, the forces are obtained using the integral momentum equation in a stationary reference frame. These experimental aerodynamic loads are compared to theoretical predictions from the Blade Element Momentum theory (BEM). Accurately determining instantaneous forces in turbines is needed for safety and understanding of their full range of operation. The standard deviation of the instantaneous forces establishes the limits of the forces expected on the turbine. The uncertainty in the measurements is calculated. The method presented may be used to measure unsteady forces in rotating airfoils, providing useful information not just for computational studies, but also for aerodynamics, material and structural optimization and safety purposes.
Nonlinear Vibration Solutions of Nano-Beams Considering Surface Effects
Authors: Askari Hassan , Esmailzadeh Ebrahim , Younesian Davood
Published: April 2014

Nonlinear free vibration of nanobeams considering the surface effects is studied. The governing differential equation of motion of the system employing the Euler-Bernoulli beam theory is derived. Galerkin method is utilized to obtain the nonlinear ordinary differential equation of nanobeams, which is a well-known type of the Duffing equation. The elliptical harmonic balance method, energy balance technique and the variational approach are employed to obtain the frequency-amplitude relationship of the system. The effects of different parameters, i.e., aspect ratio, nonlocal parameter and the resultant residual stress, on the natural frequency are examined. Moreover, the variation of the amplitude on the frequency response is studied. The influence of the initial amplitude on the obtained modulus from the elliptical harmonic balance has been examined. Furthermore, the exact numerical solution is determined to verify the results obtained from the analytical solutions.
A Design-of-Experiments Approach to Study Thermal Property Effects on Melt Pool Geometry in Powder-Based EBAM
Authors: Cheng Bo , Chou Kevin
Published: April 2014

Powder-based electron beam additive manufacturing (EBAM) is capable of making full-density metallic parts and has been increasingly utilized to produce complex-shaped, custom-designed Ti-6Al-4V alloy parts. EBAM also has the potential using other various powders materials such as intermetallics. Different materials will have different thermal properties that will result in distinct thermal responses during the EBAM process and thus, selecting adequate process parameters can be challenging. Because virtually all thermal properties would change when a different material was selected, testing individual thermal property is insufficient to understand the anticipated thermal response when a different powder material is to be used.

In this study, EBAM process thermal simulations were extended to study the effect of thermal properties in EBAM in a more systematic way using the design of experiments approach. Four factors, two levels, and full factorial experiments were conducted. Three simulation response of melt pool geometry was evaluated using analysis of variance (ANOVA). It is concluded that the thermal conductivity and the melting temperature are the two most significant factors.
Assessment of the Dynamic Response of a Lumbar Spine Functional Unit Under Axial Compressive High Loading Rate: Outcome on the Axial Disc Bulge and its Relation to the Load Magnitude
Authors: Thorbole Chandrashekhar K. , Jorgensen M. , Lankarani H. M.
Published: April 2014

Human lumbar spine tolerance to the compressive impact loading is less when compared to its tolerance to the perpendicular dynamic load. The dynamic response of the functional spinal unit in compressive loading is governed by the viscoelastic behavior of the IVD (Intervertebral disc). The axial bulge of the disc is the result of viscoelastic nature of the nucleus which tends to swell under high loading rate. This characteristic causes the end-plate to bow into the cancellous bone as it is supported by the strong cortical bone on its periphery. The end-plate is one of the important elements in the functional spinal unit if failed results disc material to progress into the vertebral body beneath it.

This paper quantifies the axial bulge of the end-plate under dynamic compressive load using Finite Element Method. A simple validated axis symmetry FE model is employed to identify the most vulnerable lumbar spine level using the sensitivity analysis. This is followed by the development of more detailed FE model with viscoelastic modeling of the nucleus and the annulus. The dynamic load is applied on the superior vertebral body which follows triangular loading profile with 50ms rise time. The axial bulge is quantified at the center of the disc as this is the location of maximum deflection and local stress in the end-plate. The ratio of axial bulge and the total FSU deflection is plotted against magnitude of load applied to gain insight regarding the relation between load magnitude and axial bulge.

This study will complement the research on end-plate fracture mechanism and its role in causing the burst fracture based on the magnitude of load.
Stress Relaxation Measurement of Agar Using a Polymer-Based Microfluidic Device
Authors: Shen Jiayue , Cheng Peng , Gu Wenting , Stacey Michael , Hao Zhili
Published: April 2014

In light of the significance of the viscoelastic property of agar to cell-based tissue engineering, this paper presents the stress relaxation measurement of agar using a polymer-based microfluidic device. Comprised of a single polymer rectangular microstructure and a set of electrolyte-enabled distributed transducers, this device is capable of detecting continuous distributed static and dynamic loads. In the measurement, an agar specimen is placed on the device and a rigid probe is utilized to press the specimen against the device with a step displacement input. Consequently, the stress relaxation behavior of the specimen translates to time-dependent continuous distributed loads acting on the device and is further registered as discrete resistance changes by the device. Two agar specimens of 1% and 3% in concentration, respectively, are measured using this device; and the data analysis is conducted on the measured results to extract Young’s relaxation modulus, which is further expressed by a Prony-series representation of the Maxwell model with two exponential terms. The results demonstrate the feasibility of using this device to measure the stress relaxation behavior of soft materials.
Acoustic Wave Microsensor Array for Tactile Sensing
Authors: Kim Kyungrim , Jiang Xiaoning
Published: April 2014

Tactile perception is a critical requirement for surgery procedures such as minimally invasive surgery (MIS). In this study, an acoustic wave tactile sensor array for force and shear modulus sensing was investigated. This device can sense the magnitude of the applied force change and the tissue’s shear modulus change by means of detecting an electrical impedance change. The 6×6 array with a pitch of 1.3 mm was fabricated using a face-shear mode PMN-PT piezoelectric resonator which is highly sensitive to acoustic impedance load. External forces (0–5 N) were applied to the sensor and the electric impedance shift was measured. The sensitivity was found to be 56.87 Ohm/N. Imaging test results for different force and load stiffnesses were also obtained. The proposed tactile sensing technique is also favorable for a number of other biomedical applications including haptic sensors for the robotic surgery and artificial skin or fingers.
Submicron-Scale Condensation on Hydrophobic and Hydrophilic Surfaces
Authors: Yamada Yutaka , Ikuta Tatsuya , Nishiyama Takashi , Takahashi Koji , Takata Yasuyuki
Published: April 2014

Condensation heat transfer is a widely-used technique for industrial applications represented by heat exchanger because of its high heat transfer coefficient. To enhance its performance, a suitable surface is required, where both condensation and droplet removal smoothly occur. In this study, we compared wettability of a graphene surface and an amorphous carbon surface. The result shows that an amorphous carbon surface is more hydrophilic. Then we prepared a graphite surface which has nanoscale hydrophilic regions in large hydrophobic area. We observed the submicron-scale droplet condensation occurs preferentially on the hydrophilic graphite step by using environmental scanning electron microscope (ESEM).
Occupant Modeling for Injury Risk Computation in Vehicle Fleet Frontal Crash Simulations
Authors: Samaha Randa Radwan , Prasad Priyaranjan , Kamalakkannan Sarath , Kommineni Vamsi , Nix Lilly , Digges Kennerly H.
Published: April 2014

Occupant model environments (MADYMO) are developed for four surrogate vehicles for injury risk computation in frontal crash fleet simulations: a small passenger car, a midsize passenger car, a midsize sport utility vehicle and a full size pickup truck. This research supports the initial implementation of a novel methodology for Evaluating Fleet, i.e., self and partner, Protection (EFP) of new vehicle designs through a systems modeling approach driven by structural and occupant modeling and real world crash and full scale test data. A two part general framework for development of occupant models for fleet vehicles is established: model development (Part I) and model verification and robustness evaluation (Part II). In Part I, current generic occupant models with seat belt and airbag restraints are obtained from restraint manufacturers and then modified to reflect the interior geometry and clearances of the desired vehicle. Data from finite element structural simulations, including the occupant compartment geometry, crash pulse, and toe pan intrusions, are utilized to drive the MADYMO models. Restraint system and dummy seating changes are incorporated to achieve a realistic match for both midsize male and small female driver dummy responses from available frontal crash tests. Part II involves comparing occupant responses from simulation and test data, and assessing trends in occupant responses in selected crash configurations for application in frontal crash fleet simulations.
Investigation of an Unsteady Flow Behavior Through a Valveless Microvalve With Step Expansion Shape
Authors: Nejat Amir , Kowsary Farshad , Hasanzadeh Amin , Ebrahimi Saman
Published: April 2014

This paper investigates the unsteady characteristics of flow in a specific type of microvalve with sudden expansion shape. The geometry of the channel is such that the flow resistance caused by vortex structures is different in forward and backward flow directions. This introduces the geometry as a good nominee as a microfluidic rectifier with application in micropump systems and MEMS-based devices. A time-varying sinusoidal pressure was set at the inlet of the microchannel to produce unsteadiness and simulate the pumping action. The existence of block obstacle and expansion shoulders leads to various sizes of vortex structures in each flow direction. All simulation results are based on the numerical simulation of two-dimensional, unsteady, incompressible and laminar Navier-Stokes equations using finite element algorithm. Two fundamental parameters are varied to investigate the vortices growth throughout the time: the frequency of the inlet actuating mechanism and the amplitude of the inlet pressure. The frequency of the inlet pressure was varied in the range of 1 Hz to 1000 Hz to cover the frequency range in many micropump applications. In this way, one can see the effect of actuation mechanism on onset of separation and follow the size and duration of the vortex growth. In order to better understand the effect of geometry and frequency on flow field, the pressure contours are studied through one cycle. Finally, Strouhal number is calculated for frequency to obtain a measure of unsteadiness of the flow. A critical value of f = 250Hz is found for St = 1. The obtained results give a deep insight into the physics of unsteady flow in valveless microvalves and lead to better use of current design as a part of microfluidic system.
Numerical Modeling of the Moisture Transfer Through Wooden Desk by Linking Ansys and Matlab Software
Authors: Simeunovic Goran , Oswaldova Ivana , Vyhlidal Tomas , Zítek Pavel
Published: April 2014

In the presented research, numerical modeling tools are applied to study relation between the moisture distribution and related stress and strain in a painted wooden desk. The research is motivated by a Case study analysis of the impact of indoor air relative humidity (RH) changes to the collection of mediaeval wooden panel paintings located in the Chapel of the Holy Cross at Karlstejn Castle. This problem is being investigated as one of the tasks of the European project Climate for Culture (http://www.climateforculture.eu/). In the analysis, CFD model of airflow movement and RH distribution in the chapel is linked with a Matlab script used to simulate moisture and stress/strain fluctuations related to RH changes in diurnal and annual cycles. The temperature and RH distribution in the room obtained by Fluent 3D CFD model of the chapel, which is generated in GAMBIT, are used as boundary conditions for the numerical computing of the moisture transfer and stress field implemented in the Matlab script.
A New Way to Present the Important but Difficult Topic of Statistical Mechanics to Engineers
Authors: Dartnall W. John , Reizes John A.
Published: April 2014

As a subject in an engineering course, Engineering Thermodynamics has earned a reputation for being difficult to understand. Quite often students practice many problems until they can do the assigned tasks, but they still feel mystified by concepts such as entropy. Even though we may use them competently, energy, enthalpy and temperature are not necessarily well understood at a concept level. Statistical Mechanics provides an excellent way of understanding the concepts more fundamentally but the traditional mathematical derivations in Statistical Mechanics require considerable time and effort before a learner gains the comfort of familiarity. Various approaches using spread-sheets to construct combinatorial illustrative examples have been published. An approach based on molecular dynamic simulation is presented in this paper, in which comparisons between actual outcomes of simulations based solely on Newtonian mechanics are compared with the probability based models. Accordingly, this approach allows explanations which meet the objective of demystifying some of the concepts that have hitherto been the bane of undergraduate thermodynamics.
Compartment Fire Growth Effects on Firefighter Alarm Signal Detection
Authors: Abbasi Mustafa Z. , Suits Joelle I. , Wilson Preston S. , Ezekoye Ofodike A.
Published: April 2014

When firefighters are overcome by the heat or smoke of a fire and become disoriented or trapped in a structure, it is crucial that there is a reliable means to alert other fireground personnel to their need for assistance. Personal Alert Safety System (PASS) devices are designed to signal for aid using audible signal technology. Normal operation is for the PASS devices to activate a 95-decibel multiple-frequency alarm signal if the device is stationary for a specific period of time or is manually activated. However, despite its widespread use throughout the fire service and on-going enhancements in recent years, certain problems still exist with audible PASS technology. Foremost among these problems is that nationally recognized standards currently do not specify a unique PASS alarm signal, and this has resulted in multiple different PASS alarms being used in the field. In this work, we present results that seek to establish a scientific basis for an optimum PASS alarm signal for use throughout the U.S fire service. We present typical sounds recorded from firefighter operations. We discuss how these sounds interfere with typical PASS signals both in compartments with and without fire. Using experimental and computational results for sound propagation within compartments with fire and thermal stratification, we show how acoustic signals are modified and affected in the gas phase by the fire evolution. Additionally, the effects of thermal degradation of typical building materials such as gypsum board is discussed in terms of the impacts on sound propagation.
Roll-Over Stabilization Mechanism Incorporating a Modified Suspension System
Authors: Ramanujam Ramdoss Varun Das , Swaminathan Ganesh Kumar , Banerjee Anomitra , Kishore Kumar Deepan
Published: April 2014

This paper provides a brief description of a Rollover Stability Mechanism in modern day cars incorporating the use of a modified suspension system which enables us to stop unexpected vehicle rollovers while they take place. Rollover mechanisms in conventional cars are incorporated with the help of anti roll bars which helps in stabilizing the car. Modern day cars are incorporated with user controlled programmes which would automatically control the car before the rollover takes place. The ESC (Electronic Stability Control) is one of those programmes which uses both ABS (Anti Brake Locking System) and TCS (Traction Control System) systems. This system identifies the various prerequisites that take place before a rollover and takes appropriate measures to avoid the forthcoming rollover. Inspite of this we see a lot of accidents due to over speeding ultimately leading to rollover at the turns or skidding of the car in tight turns at high speeds. This paper focuses on a method which can be used as a secondary safety measure for rollover accidents. The system discussed in this paper elaborates the use of a modified suspension system which is incorporated with the modern day ESC (Electronic Stability Control) unit in the vehicle. The Suspension used here is a hydraulic suspension system which is literally a piston cylinder arrangement with an inlet and outlet port for the hydraulic fluid.
Spatial Optimization of Thermal Conductivity to Enable Precise Fluid Heating and/or Cooling
Authors: Harandi Amir , Farquhar Tony
Published: April 2014

We consider a fluid flowing within a microchannel embedded in a long bar or strip. If the thermal conductivity of this bar is varied spatially in exactly the right way, the moving fluid can be subjected to arbitrary heating and/or cooling, simply by holding two opposing edges of the bar at different temperatures. With this concept in mind, the objective of this study was to develop a rigorous procedure to identify the pattern of thermal conductivity needed to achieve any particular heating/cooling profile. It is relatively straightforward to fabricate such a bar using laminated composite materials, whose precisely graded composition is comprised of comb-like metal structures embedded within polymeric layers. Within certain practical limits, one can thereby obtain relatively steep (>100C/mm) heating and cooling gradients, which makes it possible to cycle over a relatively wide range of temperatures (>100C) over a relatively short length scale (<10mm). When the desired temperature profile is known, the task at hand is the determination of the required model geometry. This inverse problem can be solved by embedding an inner loop of thermofluidic analysis within an outer loop of numerical optimization. Given a reasonable starting guess, one can move iteratively towards a comb geometry that can better match the desired temperature profile. Of practical value, the starting guess can have far fewer degrees-of-freedom than the optimal solution. In this particular study, the inner loop was performed using finite element methods (i.e., COMSOL Multiphysics 4.2), and the outer loop was implemented using SQP constrained optimization (i.e., MATLAB R2011).
Effect of Zinc Oxide Nanowire Length on Interfacial Strength of Carbon Fiber Composites
Authors: Patterson Brendan A. , Sodano Henry A.
Published: April 2014

Vertically aligned arrays of zinc oxide nanowires can serve as an adjustable interface for fiber composites through controllable synthesis techniques. When grown on carbon fiber surfaces as a fiber-matrix interphase of a composite, ZnO nanowires increase the surface area of interaction between fiber and matrix, and thus cause a greater interfacial shear strength of the composite. The ability to control the interfacial strength of this interphase through tailored morphologies enables the design of composite systems to specific applications. This report focuses on the controlled growth of ZnO nanowires and correlates the relationship between nanowire length and interfacial shear strength of the composite. Previous studies have focused on the effects of nanowire morphology on the interfacial strength; however, the data was limited to nanowire lengths < 1μm due to problems with nanowire uniformity and cleanliness [1]. Here, a new synthesis method is applied to the growth of zinc oxide nanowires on carbon fiber that enables the production of long, vertically aligned, uniform nanowires while maintaining the tensile properties of the fiber. The nanowires created by the new method are then compared to previous method nanowires by scanning electron microscopy imaging. Lastly, the interfacial shear strength of the fiber/polymer matrix composite is tested using single fiber fragmentation and correlated to the nanowire length of each method.
Design, Analysis and Simulation of an Intake Manifold
Authors: Calvo Andres , Garcia Hector , Carbajal Gerardo
Published: April 2014

A complete intake manifold was designed and built for a 600cc engine. This device was part of the engine’s air admission system for use in a formula type racecar for an engineering competition. The effect of the plenum volume, plenum shape, inlet restrictor geometry, and runner length, and how these affect the intake manifold performance was numerically investigated. A CFD based FEA software, Ricardo WAVE, was used to model the engine parameters and intake geometries, and perform running engine simulations to evaluate the intake manifold’s performance. Different acoustic geometries were generated, tested and simulated with Ricardo WAVE via parametric iterations. The intake manifold’s performance capacity was tested; torque and horsepower curves were measured under controlled operating conditions in a dynamometer and compared with Ricardo WAVE results. It was found an acceptable agreement between the numerical and experimental data.
Characteristics of Falling Impact of Head Using a Test Dummy
Authors: Hajiaghamemar Marzieh , Seidi Morteza , Caccese Vincent , Shahinpoor Mohsen
Published: April 2014

Traumatic Brain Injury (TBI) contributes to a major number of deaths and cases of permanent disability each year. Falls are the leading cause of TBI with the highest rates for children 0–4 years old and for adults age 75 and older. Accordingly, there is a significant interest in fall-related injury mechanism and head impact. Since the dynamics of human fall and head injury mechanisms are highly variable due to the inherent and complex nature of human falling, the aim of the present study is to describe the dynamics of backward falls and risk of injury due to head impact. In order to have a better understanding of head impact, A HYBRID III 5th Percentile Female test (Denton ATD, Inc.) instrumented with a tri-axial accelerometer with measuring range of ±500g at the center of gravity of the head was dropped from standing posture by using a controlled release mechanism. The dynamic model of fall was captured using a T-series Vicon motion capture system synchronized with a force plate to measure the impact force and a tri-axial accelerometer to measure the impact acceleration of the head. The acceleration impact data measured at 20 KHz and the motion capture system was capable to retrieve 500 samples per second. The primary objective of this study was to determine the equivalent mass involved during head impact due to a backward fall. This effective mass is a key quantity to design the head impact experimental setups, protection devices and computer simulations of head impact. Based on the force and acceleration measurements in several tests, the head impact effective mass is approximately found to be the mass of head itself plus 48% the neck mass. Two scenarios of backward fall were studied and discussed. First, falling while the hip joints are involved and the trunk moves forward and second, falling while the hip joints act like a fixed joint. For the first scenario the impact forces and accelerations peak measured using the HYBRID III were found to be 10±1.8KN and 255±42g, respectively, and for the second scenario the larger impact forces, 14.5±0.9KN, and acceleration peaks, 364±27g, were measured in all tests.
Parallel Molecular Dynamics Simulations and Immersive Visualization of Thermal Barrier Coating Components: Thermally Growing Oxide and Yttria Stabilized Zirconia
Authors: Kodiyalam Sanjay , Benissan Michael , Akwaboa Stephen , Mensah Patrick F. , Jana Amitava , Bagayoko Diola
Published: April 2014

Non-equilibrium parallel molecular dynamics simulation is used to determine the thermal conductivity of Alumina in the [2 1 1 0]direction at 1200 K: When thermal expansion is not allowed it is found to be 3.45 W/mK, while with thermal expansion it is 2.95 W/mK. A short ranged empirical potential for Yttria stabilized Zirconia (YSZ) is developed by fitting to available ab initio and experimentally derived data for Zirconia. With this potential, simulations of YSZ at 2073.16 K, with 4.9–23.1 mol% of Yttria in Zirconia, shows diffusing Oxygen and non-diffusing Zirconium and Yttrium atoms as expected. However, the diffusion constant of oxygen increases with the Yttria content, inconsistent with simulations with long range interactions showing a peak around 10 mol% of Yttria and also inconsistent experiment at 923 K. Visualizing the dynamics of atoms in Alumina, when driven by a heat-current forcing perturbation, shows phonon-like modes indicating the need for smaller perturbation or an alternate method to determine thermal properties.
The Effect of an Operator Compartment Door on Standup Forklift Off-Dock and Tip-Over Injuries
Authors: Wiechel John F. , Scott William R. (Mike)
Published: April 2014

A series of tip-over and off-the-dock impact tests were performed with stand-up forklifts in order to investigate the potential for injury to the operator of a forklift in these types of accidents when the forklift is equipped with an operator’s compartment door. One Crown Equipment Company RR Model and one RC Model stand-up forklift were used in the impact tests. The only modification to the forklifts for the tests was the placement of a door on the entrance to the operator’s compartment. A Hybrid III anthropomorphic test device (ATD) was placed in the operator’s compartment as a human surrogate. During each test, head accelerations, chest accelerations, neck loads and lumbar loads were measured on the ATD. The motion of the forklift and the ATD were filmed with video and high-speed cameras. Results from the impact tests indicate that there is a high risk of head injury in a right side tip-over accident and a high risk of head injury and neck injury in a left side tip-over accident. There is a high risk of a head injury, neck injury and thoracic injury in off-the-dock forks-trailing accidents. In an off-the-dock forks-leading accident there is a high risk of arm/shoulder injury, head injury, and neck injury. In both tip-over and off-the-dock forks-trailing accidents there is a high probability of an entrapment injury under the overhead guard on the forklift.
IL-18 Attenuates Experimental Choroidal Neovascularization as a Potential Therapy for Wet Age-Related Macular Degeneration
Authors: Doyle Sarah L. , Ozaki Ema , Brennan Kiva , Humphries Marian M. , Mulfaul Kelly , Keaney James , Kenna Paul F. , Maminishkis Arvydas , Kiang Anna-Sophia , Saunders Sean P. , Hams Emily , Lavelle Ed C. , Gardiner Clair , Fallon Padraic G. , Adamson Peter , Humphries Peter , Campbell Matthew
Published: April 2014

IL-18 prevents choroidal neovascularization, the hallmark pathology of wet AMD, and is not toxic to the retinal pigment epithelium.
Shear Forces Enhance Toxoplasma gondii Tachyzoite Motility on Vascular Endothelium
Authors: Harker Katherine S. , Jivan Elizabeth , McWhorter Frances Y. , Liu Wendy F. , Lodoen Melissa B.
Published: April 2014

Toxoplasma gondiiis a highly successful parasite that infects approximately one-third of the human population and can cause fatal disease in immunocompromised individuals. Systemic parasite dissemination to organs such as the brain and eye is critical to pathogenesis.T. gondiican disseminate via the circulation, and both intracellular and extracellular modes of transport have been proposed. However, the processes by which extracellular tachyzoites adhere to and migrate across vascular endothelium under the conditions of rapidly flowing blood remain unknown. We used microfluidics and time-lapse fluorescence microscopy to examine the interactions between extracellularT. gondiiand primary human endothelial cells under conditions of physiologic shear stress. Remarkably, tachyzoites adhered to and glided on human vascular endothelium under shear stress conditions. Compared to static conditions, shear stress enhancedT. gondiihelical gliding, resulting in a significantly greater displacement, and increased the percentage of tachyzoites that invaded or migrated across the endothelium. The intensity of the shear forces (from 0.5 to 10 dynes/cm2) influenced both initial and sustained adhesion to endothelium. By examining tachyzoites deficient in theT. gondiiadhesion protein MIC2, we found that MIC2 contributed to initial adhesion but was not required for adhesion strengthening. These data suggest that under fluidic conditions,T. gondiiadhesion to endothelium may be mediated by a multistep cascade of interactions that is governed by unique combinations of adhesion molecules. This work provides novel information about tachyzoite interactions with vascular endothelium and contributes to our understanding ofT. gondiidissemination in the infected host.

IMPORTANCEToxoplasma gondiiis a global parasite pathogen that can cause fatal disease in immunocompromised individuals. An unresolved question is how the parasites circulate in the body to tissues to cause disease.T. gondiiparasites are found in the bloodstream of infected animals and patients, and they have been shown to adhere to and cross the endothelial cells that line blood vessel walls. To investigate these interactions, we devised a microfluidic system to visualize parasites interacting with vascular endothelium under conditions similar to those found in the bloodstream. Interestingly, parasite migration was significantly influenced by the mechanical force of shear flow. Furthermore, we identified a role for the parasite surface protein MIC2 in the initial phase of adhesion. Our study is the first to document T. gondiiinteractions with endothelium under shear stress conditions and provides a foundation for future studies on the molecules that mediate parasite interaction with the vasculature.
Methylmalonic acidaemia in pregnancy
Authors: Jacquemyn Yves , Den Hartog Marieke , Eyskens Francois
Published: March 2014

A 27-year-old woman with vitamin B12responsive form of methylmalonic acidaemia (MMA) was pregnant with her first child. Treatment was unaltered during pregnancy: a low-protein diet and supplements. Her pregnancy was uncomplicated. She had a spontaneous delivery of a healthy girl with no MMA. The postpartum period was uneventful. MMA is a rare autosomal recessive metabolic disorder caused by a deficiency of methylmalonyl coenzyme A mutase or its vitamin B12-dependent cofactor, leading to a toxic accumulation of methylmalonyl acid in plasma and urine. Clinical presentation involves otherwise unexplained deterioration and neurological dysfunction, recurrent vomiting, dehydration, lethargy, respiratory distress and muscular hypotonia. Long-term sequelae are neurological problems, renal failure, pancreatitis and cardiomyopathy. This is the 11th reported case of pregnancy in a woman with MMA.
Barriers to accurate diagnosis and effective management of heart failure have not changed in the past 10 years: a qualitative study and national survey
Authors: Hancock Helen C , Close Helen , Fuat Ahmet , Murphy Jerry J , Hungin A Pali S , Mason James M
Published: April 2014

Objectives

To explore changes in healthcare professionals’ views about the diagnosis and management of heart failure since a study in 2003.

Design

Focus groups and a national online cross-sectional survey.

Setting and participants

Focus groups (n=8 with a total of 56 participants) were conducted in the North East of England using a phenomenological framework and purposive sampling, informing a UK online survey (n=514).

Results

4 categories were identified as contributing to variations in the diagnosis and management of heart failure. Three previously known categories included: uncertainty about clinical practice, the value of clinical guidelines and tensions between individual and organisational practice. A new category concerned uncertainty about end-of-life care. Survey responses found that confidence varied among professional groups in diagnosing left ventricular systolic dysfunction (LVSD): 95% of cardiologists, 93% of general physicians, 66% of general practitioners (GPs) and 32% of heart failure nurses. For heart failure with preserved ejection fraction (HFpEF), confidence levels were much lower: 58% of cardiologists, 43% of general physicians, 7% of GPs and 6% of heart failure nurses. Only 5–35% of respondents used natriuretic peptides for LVSD or HFpEF. Confidence in interpreting test findings was fundamental to the use of all diagnostic tests. Clinical guidelines were reported to be helpful when diagnosing LVSD by 33% of nurses and 50–56% of other groups, but fell to 5–28% for HFpEF. Some GPs did not routinely initiate diuretics (23%), ACE-inhibitors (22%) or β-blockers (38%) for LVSD for reasons including historical teaching, perceived side effects and burden of monitoring. For end-of-life care, there was no consensus about responsibility for heart failure management.

Conclusions

Reported differences in the way heart failure is diagnosed and managed have changed little in the past decade. Variable access to diagnostic tests, modes of care delivery and non-uniform management approaches persist. The current National Health Service (NHS) context may not be conducive to addressing these issues.