bluuebunny/crossref_metadata_2025 huggingface dataset:
CO2 Capture Using Calcium Oxide Applicable to In-Situ Separation of CO2 From H2 Production Processes
Authors: Kenarsari Saeed Danaei , Zheng Yuan
Published: April 2014

A lab-scale CO2 capture system is designed, fabricated, and tested for performing CO2 capture via carbonation of very fine calcium oxide (CaO) with particle size in micrometers. This system includes a fixed-bed reactor made of stainless steel (12.7 mm in diameter and 76.2 mm long) packed with calcium oxide particles dispersed in sand particles; heated and maintained at a certain temperature (500–550°C) during each experiment. The pressure along the reactor can be kept constant using a back pressure regulator. The conditions of the tests are relevant to separation of CO2 from combustion/gasification flue gases and in-situ CO2 capture process. The inlet flow, 1% CO2 and 99% N2, goes through the reactor at the flow rate of 150 mL/min (at standard conditions). The CO2 percentage of the outlet gas is monitored and recorded by a portable CO2 analyzer. Using the outlet composition, the conversion of calcium oxide is figured and employed to develop the kinetics model. The results indicate that the rates of carbonation reactions considerably increase with raising the temperature from 500°C to 550°C. The conversion rates of CaO-carbonation are well fitted to a shrinking core model which combines chemical reaction controlled and diffusion controlled models.
Study of Turbulent Incompressible Flow Separation on High Lift Devices Using Cutcell Meshing
Authors: Ghmati Ramadan , Arslan Selin , Jawad Badih A. , Liu Liping
Published: April 2014

Generating the mesh is a crucial part in all Computational Fluid Dynamics (CFD) analysis. Considerable time and effort have to be devoted into deciding the appropriate mesh densities that compromise between computing time and the desired accuracy. It is important that engineers generate high quality meshes around complex geometries which can capture the fine details of the inner layer.

Flow separation develops when the velocity near a solid surface just becoming negative. An inflection point exists in the velocity profile due to a positive or adverse pressure gradient occurring in the direction of flow. The computational analysis carried out near wall sub-layer is one of the challenging issues due to the need for complex mesh generation.

Separation has a major effect on the drag predictions, in this paper the authors look to extend their previous work [1, 2] to assess the capability of CutCell Cartesian meshing method for predicting the turbulent incompressible flow separation when applied to high lift devices. Although there is no experimental data available to verify the computational work, results can be the subject of future work to identify the factors which lead to flow separation experimentally. Complex aerodynamics shapes will be used and numerical simulation will be conducted using ANSYS Meshing and Fluent.
Numerical Modeling of the Acoustic Damping of Perforated Liners With Bias Flow
Authors: Mazdeh Alireza , Kashani Ahmad Reza
Published: April 2014

Acoustic damping properties of perforated liners are highly dependent on a number of variables which can be categorized as “flow variables” such as the extent and Mach number of grazing flow as well as bias flow and “geometric variable” such as the shape of the hole which can be rectangular, cylindrical, conical with diverging or converging nozzle, thickness to radius ratio, radius to hole spacing ratio and hole orientation which can be normal to or inclined with respect to the perforated plate.

Theoretical and empirical approaches have provided the foundation for understanding the damping properties of liners but they are based on certain simplifying assumptions making them inadequate in addressing the realistic conditions encountered in industrial applications. These limitations have highlighted the importance of numerical methods for studying damping behavior of liners. Acoustic attributes of perforated plates (mainly in terms of impedance as a function of non-dimensional variables like Reynolds, Strouhal, Mach, and Helmholtz numbers have been studied by various researchers, including the authors, using a variety of numerical tools starting from the simple 1D network scheme based on linear acoustics all the way to the computationally intensive Large-Eddy Simulations (LES) and Scaled Adaptive Simulation (SAS) reconstructing the full unsteady turbulent structures. Although the impacts of some geometry variations such as hole inclination angle and diameter, in conjunction with various fluid dynamic parameters, have been investigated using 1D network tools, the focus of LES has been mainly on analysis of a single circular hole with periodic boundary conditions as the representation of multi-perforation (assuming the perforations are spaced far enough from each other so that there is no interaction between neighboring holes). There is certainly a need for thorough investigation of the acoustic impact of these geometric parameters as well as the shape of the holes using LES.

In an on-going research we are extending the numerical modeling work on characterizing the acoustic damping attributes of a perforation, beyond the current state of the art, by including the geometric variables including hole size, shape, orientation, and radius to thickness ratio, amongst others, in the study. In this paper, following a short review of the research conducted in the recent past, we present our findings on the impact of the thickness/radius ratio on the acoustic damping attribute of a perforation.
Unbalanced Response of Cracked Rotor-Bearing System Under Time-Dependent Base Movements
Authors: Han Qinkai , Chu Fulei
Published: April 2014

Unbalanced response of cracked rotor-bearing system under time-dependent base movements is studied in this paper. Three base angular motions, including the rolling, pitching and yawing motions, are assumed to be sinusoidal perturbations superimposed upon constant terms. Both the open and breathing transverse cracks are considered in the analysis. The finite element model is established for the base excited rotor-bearing system with open or breathing cracks. Considering the time-varying base movements and transverse cracks, the second order differential equations of the system will not only have time-periodic gyroscopic and stiffness coefficients, but also the multi-frequency external excitations. An improved harmonic balance method is introduced to obtain the steady-state response of the system under both base and unbalance excitations. The whirling frequencies of the equivalent time-invariant system, orbits of shaft center, response spectra and frequency response characteristics, are analyzed accordingly. The effects of various base angular motions, frequency and amplitude of base excitations, and crack depths on the system dynamic behaviors are considered in the discussions.
Measured Variation of High Frequency Sound Absorption in Porous Metals Subject to Changes in Temperature and Temperature Gradient
Authors: Chen Weihua , Chen Tianning , Wang Xiaopeng , Ying Zhiping
Published: April 2014

Porous metal, as a new acoustic material, bears the general metal properties, such as good conductivity, ductibility, heat transfer and high specific stiffness and intensity, and meanwhile exhibits good performance in sound absorption. Thus, it enjoys a growing popularity in industrial and civilian sound-absorbing applications where non-metallic materials are impracticable. Therefore it is of great significance to explore the sound-absorption properties of porous metals. The existing studies mainly focus on the low frequency range and are under uniform temperature assumption. In this paper, an experimental setup was built up to investigate the sound absorption of porous metals subject to temperature gradients, and much concern was paid to that of high frequency range. The setup is composed of five modules: I. heating module; II. cooling module; III. temperature controlling & testing module; IV. spectrum analyzer and V. impedance tube testing module. Based on this setup, the sound absorption of a hard-backed porous metal in a high-frequency range (2000–4000Hz)and under different temperature gradients (+2°C/mm, +4°C/mm and +6°C/mm) are measured, and results show that: 1) The sound absorption of porous metal is significantly influenced by temperature gradients; 2) The peak of sound absorption curve moves to a higher frequency range as the temperature gradient increases in the frequency range 2000∼4000Hz but the peak value decreases slightly; 3) The peak value of sound absorption curve enlarges as the temperature gradient increases but the frequency of peak value is fixed.
Production, Performance and Emissions of Biodiesel as Compression Ignition Engine Fuel
Authors: Datta Ambarish , Mandal Bijan Kumar
Published: April 2014

The enhanced use of diesel fuel and the strict emission norms for the protection of environment have necessitated finding sustainable alternative and relatively green fuels for compression ignition engines. This paper presents a brief review on the current status of biodiesel production and its performance and emission characteristics as compression ignition engine fuel. This study is based on the reports on biodiesel fuels published in the current literature by different researchers. Biodiesel can be produced from crude vegetable oil, non-edible oil, waste frying oil, animal tallow and also from algae by a chemical process called transesterification. Biodiesel is also called methyl or ethyl ester of the corresponding feed stocks from which it has been produced. Biodiesel is completely miscible with diesel oil, thus allowing the use of blends of mineral diesel and biodiesel in any percentage. Presently, biodiesel is blended with mineral diesel and used commercially as fuel in many countries. Biodiesel fueled CI engines perform more or less in the same way as that fueled with the mineral diesel. Exhaust emissions are significantly improved due the use of biodiesel or blends of biodiesel and mineral diesel. The oxides of nitrogen are found to be greater in exhaust in case of biodiesel compared to mineral diesel. But the higher viscosity of biodiesel also enhances the lubricating property. Biodiesel being an oxygenated fuel improves combustion.
Flow and Heat Transfer Characteristics of a Novel Heat Exchanger
Authors: Ma Haolin , Oztekin Alparslan
Published: April 2014

Computational fluid dynamics and heat transfer simulations are conducted for a novel shell-tube type heat exchanger. The heat exchanger consists of tube with a narrow slot oriented in the streamwise direction. Numerical simulations are conducted for the Reynolds number of 1500. The 3D turbulent flow in the tube bank region is modeled by k-ε Reynolds stress averaging method by employing ANSYS FLUENT. 3-D transient flow and heat transfer simulations are conducted to determine the flow structure and temperature profiles in the wake of cylinders in the first row and other rows. The effects of the slot size and the orientation and the arrangement of the cylinder in different configuration will be examined. The slotted tube heat exchanger improved heat transfer by more than 27% compare to the traditional shell-tube heat exchanger without slots. Enhancement in heat transfer is even higher at higher values of Reynolds number.
The Theoretical and Numerical Analysis of Thickness-Shear Mode in a Two-Layered Piezoelectric Plate Transformer With a Viscoelastic Interface
Authors: Tang Liling , Li Peng , Jin Feng
Published: April 2014

A thickness-shear mode in a two-layered piezoelectric plate transformer with an imperfect interface is proposed. Based on the shear-slip interface model which is used to simulate the influence of viscoelastic imperfect interface, an exact solution from the three-dimensional equations of piezoelectricity is obtained. Numerical results reveal the effects of interface parameters on the transforming ratio, power density, input admittance, efficiency and displacement and stress distributions along the thickness direction, which could offer theoretical guidance in the design of piezoelectric transformers.
Detection of DNA in a Nanopore Fabricated From Glass Tube
Authors: Sha Jingjie , Chen Yunfei
Published: April 2014

Nanopores are increasingly utilized as tools for single molecule detection in biotechnology. Here, we report an improved fabrication process to make solid-state nanopores from glass tubes with the help of paraffin. Based on the physical footprint of the phase change of the paraffin, nanocavity is formed in the broken terminal after thermally compressing and pulling the glass capillary. Nanopores with the minimum diameter of 20 nm are fabricated. The key step is to control the thickness of paraffin layer attached in the inner wall, which could affect the diameter of the nanopore.

We investigate 48Kb λ-DNA molecules translocate through the fabricated glass nanopore. Because DNA molecules with the negative charges could be driven by the electrical force to pass through the nanopore and could physically block the pore to produce measurable changes in ionic currents. A transient electrical current changing is used to detect the DNA molecules in the solution. In the experiments, many events of DNA translocation were observed under the positive potential. We demonstrate that DNA molecules could be detected by the nanopore fabricated from glass tube.

However, we also find the events of DNA translocation under the negative potential, which is because of the electro-osmotic flow (EOF) effects. It is found that the electro-osmotic flow inside the nanopore plays an important role in the DNA translocation process, and thus depends on the size of the pore. We shows that the effective driving force on DNA in a nanopore is the co-effects of the force of the electric field and the drag force of the electro-osmotic flow.
Optimization for Slip Analysis of Belt Drives With Finite Element Verification
Authors: Hussein Muhammad M. , Hussein Bassam A. , Metwalli Sayed M.
Published: April 2014

This paper presents optimized nonlinear analytical procedure for the slipping and sticking motion of extensible belt pulley systems. The procedure initially assumes a general spline representing the changes in the internal moment along the slipping zones. This assumption enables one to get the shear force values along the belt length. Also this assumption enabled us to discover an entrance slipping zone of the belt pulley contact with all variables changing along this zone. The contact between the belt and the pulley has thus three stages that lead to more realistic prediction of the belt system variables and more accurate values for the angles in the belt pulley sliding zones. The change in the angular velocity of the driven pulley with respect to the driving pulley, the change in the cross section dimensions, and the belt stretch are predicted. The analytical model gives highly nonlinear equations which are solved by numerical optimization procedure and validated by the solution obtained using absolute nodal coordinate formulation (ANCF) finite element method. The results obtained demonstrate that the present formulation leads to more accurate prediction for the belt tension, friction and normal forces. This paper presents the analytical results of several models which are presented and would enable better prediction for the critical loads for several cases.
Design for Internal Resonances in Nonlinear Transverse Vibrations of Hyperelastic Plates
Authors: Tripathi Astitva , Bajaj Anil K.
Published: April 2014

Nonlinear phenomenon such as internal resonance have significant potential applications in Micro Electro Mechanical Systems (MEMS) for increasing the sensitivity of biological and chemical sensors and signal processing elements in circuits. While several theoretical systems are known which exhibit 1:2 or 1:3 internal resonances, designing systems that have the desired properties required for internal resonance as well as are physically realizable as MEMS devices is a significant challenge. Traditionally, the design process for obtaining resonant structures exhibiting an internal resonance has relied heavily on the designer’s prior knowledge and experience. However, with advances in computing power and topology optimization techniques, it should be possible to synthesize structures with the required nonlinear properties (such as having modal frequencies in certain ratios) computationally. In this work, plate structures which are candidates for internal resonances are obtained using a Finite Element Method (FEM) formulation implemented in Matlab to iteratively modify a base structure to get its first two natural frequencies close to the desired ratio (1:2 or 1:3). Once a structure with desired topology is achieved, the linear mode shapes of the structure can be extracted from the finite element analysis, and a more complete Lagrangian formulation of the Hyperelastic structure can be used to develop a nonlinear two-mode model of the structure. The reduced-order model is expected to capture the appropriate resonant dynamics associated with modal interactions between the two modes, and the nonlinear response can be obtained by application of perturbation methods such as averaging on the two-mode model.
Evidence-Based Best Practices: Wound Healing Tracking and Assessment
Authors: Chin Jessica , Zeid Ibrahim , Kamarthi Sagar
Published: April 2014

Standard medical practice is known to have a history of varying definition of “standard”. As with any industry with multiple entities, each entity defines their standards and expectations according to what they believe is their customers’ (i.e. patients) needs and preferences. Recently, our research on developing a predictive wound care assessment methodology and system has extended our study into analyzing evidence-based best practices in wound care clinics. Our research on wound healing predictive model systems, revealed key differences in operational practice between the clinics that were visited in different institutional settings. The scope of this study evaluates our observed wound care practice and wound care treatment to determine if there is a common set of effective practice that can be developed to better standardize care. The purpose of this paper is to compare and contrast the operational practice and procedures at various community and teaching hospitals to determine if there is an ideal combination of tools and standard techniques that would be most beneficial to patient wound care. This paper will focus on methods of patient wound care. We will then present a model of “Evidence-Based Best Practices of Wound Care Assessment” that is based on the observation and interactions with various hospitals.
Numerical Calculations of Bidirectional Characteristics on Tidal Current Runner
Authors: Li Long , Chen Yu , Wang Ze
Published: April 2014

It would be a good choice to use the bidirectional tidal current runner, during the tide rises or ebbs. And how to improve its performance in both positive and reverse condition has become a seeking aim for designers. The shape of airfoil has important influence on the dynamic performance of the blade. Many researchers have proved that to choose the suitable airfoil’s camber and thickness can improve the dynamic performance of the turbine. The S-shaped airfoil was designed, considering influence of various factors. The CFD technology is used to do the numerical simulation for the airfoil’s plane flow and three-dimensional flow of the reversible turbine. The effects of the blade’s camber and thickness on the reversible turbine are analyzed, with the purpose of providing theoretical basis for optimal design of the reversible turbine. The research results show that the efficiency of the reversible turbine is lower than that of the turbine with standard airfoil, but its dynamic performance is completely identical between positive condition and reverse condition. And it can be used for generation during the tide rises or ebbs.
Numerical Analysis of Residual Stresses in V-Butt Welded Joint of Two Dissimilar Pipes
Authors: Brar Gurinder Singh , Singh Gurdeep
Published: April 2014

In this paper a three-dimensional welding simulation was carried out by commercially available finite element software to predict temperature and the residual stress distributions in V-butt welded joint of two dissimilar pipes. Low carbon steel and stainless steel pipe welding is widely used in a variety of engineering applications such as oil and gas industries, nuclear and thermal power plants and chemical plants. Inelastic deformations during heat treatment are the major cause of residual stress. Heat during welding causes localized expansion as some areas cool and contract more than others. The stress variation in the weldment can be very complex and can vary between compressive and tensile stresses. The mismatching (in the weld in general) occurs due to joint geometry and plate thickness. Welding procedures and degree of restraints also influences the residual stress distributions. To understand the behavior of residual stress, two dissimilar pipes one of stainless steel and another of low carbon steel with outer diameter of 356 mm and internal diameter 240 mm were butt welded. The welding was completed in three passes. The first pass was performed by Manual TIG Welding using ER 309L as a filler metal. The remaining weld passes were welded by Manual Metal Arc Welding (MMAW) and ER 309L-16 was used as a filler metal. During each pass, attained peak temperature and variation of residual stresses and magnitude of axial stress and hoop stress in pipes has been calculated. The results obtained by finite element method agree well with those from Ultrasonic technique (UT) and Hole Drilling Strain-Gauge (HDSG) as published by Akhshik and Moharrami (2009) for the improvement in accuracy of the measurements of residual stresses.
Fractional Order Thermoelastic Waves of Cylindrical Gold Nano-Beam
Authors: Youssef Hamdy M. , Elsibai Khaled A. , El-Bary Alaa A.
Published: April 2014

In this work, a mathematical model of cylindrical nano-beam with constant elastic parameters with fractional order heat conduction will be constructed. The governing equations of the mathematical model will be taken when the beam is quiescent first. Laplace transforms techniques will be used to get the general solution for any set of boundary conditions. The solution will be obtained for a certain model when the beam is subjected to thermal load. Inversion of Laplace transforms will be obtained numerically, and the results will be presented graphically with some comparisons to study the impact of thermal load and the effect of the fractional order parameter on the speed of progress of mechanical and thermal waves through the beam.
Evaluation Method of Thermal Comfort in Excavator Cabin
Authors: Hwang Ju Ho , Lee Jae Seok , Kim Young Hyun , Kim Pan Young
Published: April 2014

The thermal comfort in the cabin of construction equipment has been becoming one of the important issues of cabin design. In this study, a performance index related to thermal comfort is proposed as a way to evaluate the effect of location of air-conditioning vents. As the first step, cooling performance at the position of operator in the cabin is calculated by using CFD. For more reliable analysis, the results of the simulation are compared with experimental data. The evaluation of the thermal comfort is then carried out considering the change of the location of air-conditioning vent with the same boundary conditions. Cooling performance for initial 1 minute after turn on the air-conditioning is predicted from the results of thermal comfort. All of the results are used to optimize the location of air-conditioning vent in the cabin to improve the thermal conditions for the operator.
Developing a 3D Multi-Body Model of a Scoliotic Spine During Lateral Bending for Comparison of Ribcage Flexibility and Lumbar Joint Loading to the Normal Model
Authors: Hajizadeh Khatereh , Huang Mengjie , Gibson Ian , Liu Gabriel
Published: April 2014

Knowledge of the movements of the whole spine and lumbosacral joint is important for evaluating clinical pathologic conditions that may potentially produce unstable situations in human body movements. At present there are few studies that report systematic three-dimensional (3D) movement and force analysis of the whole spine. In this paper, a fully discretized bio-fidelity 3D musculoskeletal simulation model for biomechanical (kinematic) analysis of scoliosis for a patient with right thoracolumbar scoliosis is presented. It is important to note that this method can be used for modeling various types of scoliosis. It should be noted that this is the first time that such a detailed model of this kind has been constructed according to known literature.

The combined loading conditions acting on the intervertebral joints and corresponding angles between vertebrae were analyzed during lateral bending through the motion capturing and musculoskeletal modeling of two female subjects, one with normal spine and the other with scoliosis. The scoliosis subject who participated in this study has thoracolumbar scoliosis with convexity to the right. Since lateral bending is one of the typical tasks used by clinicians to determine the severity of scoliosis condition, the motion data of the subjects in lateral bending while standing was captured. These motion data were assigned to train the musculoskeletal multi-body models for the inverse and forward dynamics simulations.

The mobility of the ribcage, joint angle, as well as joint force were analyzed using the developed simulation model. According to the results obtained the combined loadings at the lumbar joints in the scoliosis model are considerably higher than the loads of the normal model in this exercise. This research has investigated the effect of thoracolumbar scoliosis on spinal angles and joint forces in lateral bending by the application of motion data capturing and virtual musculoskeletal modeling. The results of this study contribute to a better understanding of human spine biomechanics and help future investigations on scoliosis to understand its development as well as improved treatment processes.
Investigation of Scaling Effects on Post-Fatigue Residual Strength of Nanoclay Added GFRP Composites
Authors: Kavitha Nijagal Shanthaveeraradhya , Prakash Raghu V.
Published: April 2014

This paper describes the evaluation of post-fatigue residual strength of scaled laminated composites. The effect of thickness size effects of two scaled specimens on residual strength and stiffness of glass fiber reinforced plastic (GFRP) laminate with neat epoxy matrix and Nanoclay (Nanomer® I.30E) containing epoxy matrix are presented in this paper. The residual strength of a both scaled GFRP specimens with neat epoxy matrix and containing Nanoclay of 3% is determined by conducting tensile test on fatigue cycled after 2,00,000 cycles (R = 0.1). Tensile strength, residual strength and stiffness of both scaled specimens are compared with baseline or standard specimen of 4mm thick. The strength of thicker specimen (4 mm) is less compared to thinner (3mm and 2mm) specimens. The loss in strength due to fatigue loading varies with thickness of specimens, depends on the stiffness of the specimens. This complicates the transfer of mechanical properties from small scale specimen testing to use in the design of large scale structures. The stiffness increases in ply level scaled specimens and decreases in sublaminate level scaled specimens with addition of Nanoclay compared to pure epoxy matrix. The reduction in residual strength is same for different thicknesses of scaled nano-composite specimens. There is a potential in reducing scaling effects in composites with the addition of Nanoclay in matrix.
Investigation on Field-Response Performance of Magnetic-Sensitive Rubber by Impact Experiments With Adjustable Magnetic Fields
Authors: Cheng Yi , Sun Lingyu , Chen Weiwei , Leng Dingxin , Guo Zhongheng , Wang Dengfeng
Published: April 2014

A magnetic-sensitive rubber (MSR) can change its stiffness and damping characteristics with variant magnetic intensity. Hence, it is possible to use it in dissipating the impact energy adaptively. Although the relationships between elastic modulus, damping ratio and magnetic intensity have been investigated extensively by static tensile, compression or shear experiments as well as vibration tests, few literatures have shown the effectiveness of MSRs on energy dissipating during impact. In this present paper, a group of magnetic-sensitive specimens, composed by ferromagnetic particles with various volume fraction, particle dimensions at millimeter-scale or micrometer-scale, particle arrangement in chain-like or uniform distributions, and rubber matrix with three different types were manufactured. Then, a series of impact experiments aimed to test the capability of MSRs in mitigating shock was conducted by a self-developed drop hammer device with adjustable homogeneous magnetic field. The influences of the above factors on the acceleration responses were investigated. To explain the mechanism, the mathematical model of the impact process was established, and based on it; the acceleration response was obtained by MATLB software. The numerical solutions are validated by comparing with the corresponding test results. It is found that the volume fraction of particles and magnetic intensity has the obvious influences on the dynamic acceleration response, while the arrangement of macro-particle in matrix affects less. Micro-particles can change the characteristics of matrix more significantly than the macro-particles.
An Innovative Micro Actuator Using Electro Rheological Fluid Technology for Visually Impaired Tactile Display Information Technology Access Applications
Authors: Shafik M. , Mills B.
Published: April 2014

This paper presents the research has been undertaken, to design and develop a micro actuator using electro rheological fluid technology, for visually impaired tactile display information technology, access applications. The micro actuator consists of a small cylinder made of ABS plastic material with 1.5 mm diameter and 10 mm long. The inner surface of the cylinder is coated by nickel using electroless coating process. A coaxial conducting rod of 1.02 mm diameter and 10 mm long is fitted vertically in the centre of the cylinder. The coated surface is used as first electrode and the coaxial conducting rod used as a second electrode, to form the micro actuation high voltage area. The microactuator structure has been used to develop a tactile display of a large scale in a matrix form of 124×4 actuators. An advanced software tools and embedded system based on voltage matrix manipulation has been developed to provide the display the near real time control. The new micro actuator development process, software control tools and actual developed prototype is presented in this paper. Prototype size 124×4 micro actuators, on a matrix form, with a separation distance of 2.54 mm, was manufactured. The experimental tests carried out into the prototype showed that each micro actuator was able to provide a vertical movement of 0.7 mm and a vertical holding force of 100 to 200mN. These results meet the necessary standard requirement of Braille applications. Stroke and dynamic response test showed the practicability of the developed micro actuator for electronic refreshable high resolution graphical tactile display, for visually impaired and blind information technology access applications.
Magneto-Rheological (MR) Damper Design for High-Flowrate Suspensions
Authors: Meeser Riaan F. , Els P. Schalk , Kaul Sudhir
Published: April 2014

This paper presents the design of a magneto-rheological (MR) damper for an off-road vehicle where large suspension travel and high flow rates, as compared to typical passenger car suspensions, are required. The MR damper is expected to enhance the capability of the suspension system by allowing variable damping due to inherent properties of the MR fluid. MR fluids exhibit a reversible behavior that can be controlled with the intensity of a magnetic field, allowing a change in the effective viscosity and thereby in the damping characteristics of the fluid. A mathematical model of the proposed damper has been developed using the Bingham plastic model so as to determine the necessary geometry for the damper designed in this study, using the fluid flow rate and current to the electromagnet as the input variables. The model is used to compute the damping force, and the analytical results show that the designed MR damper provides the required range of damping force for the specific vehicle setup that is being used for this study. A valve-mode MR fluid channel has been designed such that the required minimum damping is reached in the off-state, and the desired maximum damping is reached in the on-state. For manufacturing and size considerations, the final design incorporates a triple pass layout with the MR fluid flowing through the three passages that are arranged in an S-shape so as to minimize the cross section of the electromagnet core.
Multiple Fault Detection and Diagnosis in a Gas Turbine Using Nonlinear Principal Component Analysis and Structured Residuals
Authors: Rincon-Charris Amilcar , Quevedo-Casin Joseba
Published: April 2014

Multiple fault detection and diagnosis is a challenging problem because the number of candidates grows exponentially in the number of faults. In addition, multiple faults in dynamic systems may be hard to detect, because they can mask or compensate each other’s effects.

This paper presents the study of the detection and diagnosis of multiple faults in a SR-30 Gas Turbine using nonlinear principal component analysis as the detection method and structured residuals as the diagnosis method.

The study includes developing a mathematical model, software simulation with Matlab Simulink and implementation of algorithms for detection and diagnosis of multiple faults in the system using nonlinear principal component analysis and structured residuals.

A real SR-30 gas turbine was used for our studies. The equipment is at the moment installed in the Inter American University of Puerto Rico, Bayamon Campus, and Department of Mechanical Engineering.
Dynamic Analysis of Offshore Oil Pipe Installation Using the Absolute Nodal Coordinate Formulation
Authors: Nielsen Jimmy D. , Madsen Søren B. , Hyldahl Per , Balling Ole
Published: April 2014

The Absolute Nodal Coordinate Formulation (ANCF) has shown promising results in dynamic analysis of structures that undergo large deformation. The method relaxes the assumption of infinitesimal rotations. Being based in a fixed inertial reference frame leads to a constant mass matrix and zero centrifugal and Coriolis forces [12]. This makes the method attractive for multibody dynamics implementation. The focus in this paper is the application of ANCF beam elements and their performance on large deformation dynamic analysis.

Large dynamic deformation is characteristic for the installation process of offshore submerged oil pipes using oceangoing vessels. In this investigation such an oil pipe is modeled using ANCF beam elements to simulate the dynamic behavior of the pipe during the installation process. Multiple physical effects such as gravity, buoyancy, seabed contact, and fluid damping, are included to mimic the external forces acting on the pipe during installation. The scope of this investigation is to demonstrate the ability using the ANCF to analyze the dynamic behavior of an offshore oil pipe during installation.
Fostering the Future STEM Workforce via Industry and Capstone Design Class Partnerships
Authors: Carmen Christina L. , Fraley Deborah L.
Published: April 2014

In order to promote the pursuit of Science, Technology, Engineering and Mathematics (STEM) education and careers among Kindergarten through 12th grade students (K-12), a partnership between the University of Alabama in Huntsville (UAH) and the Tennessee Valley Chapter of Women in Defense (WID)-a non-profit national security organization-has been established. The collaborative effort commenced as a result of the WID STEM Initiative (STEMi); a program that aims to actively encourage and inspire youth of the United States (US) to seek STEM careers. The UAH/WID partnership was initiated within a Mechanical and Aerospace Engineering (MAE) capstone design class at UAH that focuses upon the design and fabrication of unique and patentable products. In order to target the K-12 age groups, the UAH/WID effort centered upon the development of products that would inspire the younger students and allow them the opportunity to interact with a hands-on artifact that conveys a specific STEM phenomenon. Several of these artifacts-referred to as STEM tools-have been developed as a result of the UAH/WID collaboration and include the following: fluid flow circuit, interactive solar system, trebuchet, ballistic pendulum, pulley system, and a Wimshurst machine-to name a few. The hands-on STEM tools motivate younger students, as interacting with hardware reinforces theoretical concepts presented in the classroom. While the primary goal of the UAH/WID partnership is to develop the future STEM workforce by inspiring younger students, through hands-on STEM tool interaction, other critical benefits have resulted. Specifically, the engineering design students have garnered invaluable experience associated with meeting stakeholder expectations, designing with safety as a top-level criterion, as well as gaining teaching experience via lessons directed to the K-12 students. Survey data gathered from the K-12 students and teachers clearly indicates that the younger students are inspired and motivated to seek a STEM education and career as a result of the UAH/WID effort. The current paper provides an overview of the UAH/WID partnership, a description of the resulting STEM tools developed, and data conveying the learning outcome and impact that the UAH/WID partnership has had upon the K-12 students, their teachers, and the engineering students at UAH.
Random Vibration Response of a Spur Gear Pair With Periodic Stiffness and Backlash
Authors: Wen Yubing , Yang Jianming , Yang Ping
Published: April 2014

This paper investigates the random dynamic response of a spur gear pair subjected to harmonic and white noise excitations. Periodic mesh stiffness and backlash are considered in the model. The backlash is simplified as soft cubic nonlinearity. Numerical path integration is applied to capture the evolution of the joint probability density of the displacement and velocity response. The short-time transition probability density is approximated as Gaussian distribution. Gaussian closure procedure is employed to obtain the mean and variance. The random response phenomenon of a gear pair with backlash nonlinearity and periodic stiffness are compared with deterministic case to illustrate the validity of path integration.
Laminar Flame Characteristics of Partially Premixed Palm Methyl Ester Gas Flames
Authors: Romero Diego , Parthasarathy Ramkumar N. , Gollahalli Subramanyam R.
Published: April 2014

Palm methyl ester (PME) is a renewable biofuel that is produced by the transesterification of palm oil; it is a popular alternative fuel used in the transportation sector. The objective of this investigation was to study the combustion characteristics of flames of pre-vaporized diesel and PME in a laminar flame environment at initial equivalence ratios of 2, 3 and 7 and to isolate the factors attributable to chemical structure of the fuel. The equivalence ratio was changed by altering the fuel flow rate, while maintaining the air flow rate constant. The global CO emission index of the PME flames was significantly lower than that of the diesel flames; however, the global NO emission index was comparable. The radiative fraction of heat release and the soot volume fraction were lower for the PME flames compared to the diesel flames. The peak temperatures were comparable at an equivalence ratio of 2, but at higher equivalence ratios, the peak temperatures in the PME flames were higher. The measurements highlight the differences in the combustion properties of biofuels and petroleum fuels and the coupling effects of equivalence ratio.
Measurements and Models for the Thermal Conductance Through Surfaces Joined by Screws
Authors: Konkle Nicholas , Pautsch Adam , Amir Yosef
Published: April 2014

In electronics cooling with limited local convective or irradiative cooling, conduction path optimization is critical. Decreased junction temperatures (resulting in increased performance and reliability) can be achieved by maximizing the conductance through screw joints.

Thermal contact conductance across an Aluminum-Aluminum screw joint was experimentally measured which compared well with published data for uniformly distributed pressure, with increasing conductance versus the published data as the screw preload was applied. The geometry was modeled using a meshed surface application of an available model for thermal conductance of contacts with uniformly-applied pressure, resulting in a poor correlation due to limitations in the applied technique. Modifications to the model were explored, including capping pressure, imposing a non-zero pressure in the area not influenced by screw pressure, simplifying the pressure distribution, and scaling the model to match experimental results. Each resulted in somewhat better correlation between calculated and experimental results. Recommendations are made regarding the calculation of conductance in general, leaning toward more simplified models. Further work is suggested in the area of experimentally-verified modeling of other materials and surface conditions, geometry, and with an interstitial material other than air.
Experimental Characterization of Flow Regimes for a Rotating Disc Over a Range of Gas Pressures
Authors: Acharya Tathagata , Falgoust Jordan , Martin Michael J. , Rasmussen Richard E.
Published: April 2014

Experimental measurement of viscous drag is done on a rotating disc using a disc spin-down experiment in various air pressures ranging from atmospheric pressure through a vacuum pressure of 0.3 kPa. The torque is non-dimensionalized using the dynamic viscosity of air, angular velocity, and the characteristic dimension of the disc. The results can be classified as two different sets. Between atmospheric pressure and 13.3 kPa, the curves have a vertical downward trend and are connected to each other while at lower pressures the curves appear to be more horizontal. It is shown that the present experimental setup is an improvement over the old setup because the frictional torque associated with the experiment has been reduced by 25 % approximately, and the ambient pressure reached in the chamber is a fourth of the ultimate pressure reached before.
Shear Modulus Degradation in Fiber Reinforced Laminates
Authors: Salavatian M. , Smith L. V.
Published: April 2014

Matrix damage, involving transverse and shear cracks, is a common failure mode for composite structures, yet little is known concerning their interaction. A modified Iosipescu coupon is proposed to study the evolution of the shear and transverse damage and their mutual effects. The layup and coupon geometry were selected in a way that controls the severity of the damage and allows the measurement of shear and transverse stiffness degradation directly. The results were compared to material degradation models where damage was dominated by matrix failure. While positive agreement was generally observed in the transverse direction, no model was able to predict the observed shear damage. A new elasticity solution was, therefore, proposed for the shear stress-strain field of a transversely cracked laminate. The approach used a classical shear lag theory with friction applied to the crack surfaces. Using the constitutive relations, the shear modulus reduction was found as a function of crack density, and showed good agreement with experimental measures.
The Impact of Australia’s Carbon Price on the Optimisation and Selection of Gas Turbine CHP System
Authors: Gibson Chanel A. , Meybodi Mehdi Aghaei , Behnia Masud
Published: April 2014

This paper aims to indentify the impact of Australia’s carbon pricing mechanism on the optimization of a gas turbine combined heat and power (CHP) system using a thermo-economic approach. Three economic scenarios were considered: no carbon price (case one); carbon price and not liable (case two); and a carbon price and liable (case three). With the intention of demonstrating the methodology used and to identify the impact of the carbon price quantitatively, a case study was utilized. Pricing data sourced from an ongoing investigation at this institution was employed to facilitate the three economic scenarios in addition to the yearly price fluctuations. The system was permitted to operate at off-design conditions in order to determine the optimum working conditions for each month. The analysis drew on the economic indicators of net present worth and payback period. Two connection modes to the grid were considered: a single connection that allowed only for the purchasing of supplementary electricity from the grid and a dual connection which allowed both purchasing and selling of electricity.
Multi-Objective Optimization of Suspension and Seat for Vehicle Ride Dynamics Behavior Using NSGA-II Method
Authors: Song Kang , Chen Xiao-kai , Lin Yi
Published: April 2014

A seven degree-of-freedoms human body-seat-suspension model was built for multi-objective optimization of vehicle ride dynamics behavior. Biomechanical models of human body and elastic model of seat cushion were integrated with classical 1/4 car model. The root mean square values of head acceleration of human body, together with suspension work space and dynamic tire load, were selected as objective functions of optimization. Non-dimension method was introduced into the formulation of objective functions so that optimization could be independent of different running conditions. Parameter sensitivity analysis was utilized to explore the relation between objective functions and parameters of suspension and seat cushion. Based on the results of analysis, design variables were determined. Non-dominated Sorting Genetic Algorithm - II was used in this multi-objective optimization problem to compute Pareto optimal set and Pareto frontier. Results indicate that Pareto frontier includes two parts. These two parts have the nearly same range of dynamic tire load and share partial range of suspension work space in objective function space. In design variable space, two parts respectively correspond to two different distribution areas of Pareto optimal solution set. So, for the same expected objective, parameters of suspension and seat cushion usually have at least one available combination, which improves the flexibility of optimal design.
Development of Ink-Particle Flight Simulation for Continuous Inkjet Printer
Authors: Ikegawa Masato , Ishii Eiji , Harada Nobuhiro , Takagishi Tsuneaki
Published: April 2014

An ink-particle flight simulation method for industrial, continuous-type inkjet printers was developed to clarify the factors that influence the print distortion. Print distortion is produced by aerodynamic and electric interference between the ink-particles flying from the nozzle onto the print-target. The necessary functions to do this, such as the calculation of electrostatic force in the electric field between the electrodes, the Coulomb’s force from other charged ink-particles, and the drag force in the inkjet stream for many flying ink-particles were added to a Lagrangian method in the fluid dynamic analysis software that was used for the simulation. The trajectories of the ink-particles flying from this nozzle onto the print target and the air-flow caused by them were calculated simultaneously in the simulation. The simulation results for the velocities and trajectories of the flying ink-particles were compared with the experimental ones using a high-speed camera. These simulation results were in good agreement with the experimental ones, and this helps to clarify the factors that influence the print distortion.