bluuebunny/crossref_metadata_2025 huggingface dataset:
Control Strategies for a Roll Simulator for Recreational Off-Highway Vehicles
Authors: Zagorski Scott B. , Guenther Dennis A. , Heydinger Gary J. , Sidhu Anmol S. , Bixel Ronald A.
Published: August 2012

Control strategies for a two degree-of-freedom roll simulator are presented. The simulator consists of a sled-platform assembly that translates along rails. A Recreational Off-Highway Vehicle (ROV) is mounted on the platform, which has the freedom to rotate about a roll axis. The roll axis is nominally perpendicular to the rails and parallel to the ground plane. This can be altered by using the third degree-of-freedom (static) that yaws the platform and changes the angle of the roll axis with respect to the rails. This angle is incorporated to achieve the appropriate acceleration vector. The assembly accelerates to a desired speed via a hydraulic motor and is decelerated with a magnetic particle brake at a specified deceleration level (nominally 0.7 g). Coordination of two mechanical systems proved to be difficult due to inherent lags in both systems. The cable-drum system created many problems as tension needs to be maintained in the cable at all times. Using only knowledge of the physical system, results showed reasonable agreement with desired levels. The roll motions showed excellent correlation with the desired levels.
A Chaotic Blue Sky Catastrophe of Butterfly Valves Driven by Solenoid Actuators
Authors: Naseradinmousavi Peiman , Nataraj C.
Published: August 2012

Chilled water systems used in the industry and on board ships are critical for safe and reliable operation. It is hence important to understand the fundamental physics of these systems. This paper focuses in particular on a critical part of the automation system, namely, actuators and valves that are used in so-called “smart valve” systems. The system is strongly nonlinear, and necessitates a nonlinear dynamic analysis to be able to predict all critical phenomena that affect effective operation and efficient design. The derived mathematical model includes electromagnetics, fluid mechanics, and mechanical dynamics. Nondimensionalization has been carried out in order to reduce the large number of parameters to a few critical independent sets to help carry out a broad parametric analysis. The system stability analysis is then carried out by the aid of the tools from nonlinear dynamic analysis. This reveals that the system is unstable in a certain region of the parameter space. The system is also shown to exhibit crisis and chaotic responses; this is characterized using Lyapunov exponents and power spectra. Knowledge and avoidance of these dangerous regimes is necessary for successful and safe operation.
Finite Volume Method for Structural Analysis of RF MEMS Devices Using Theory of Plates
Authors: Das Shankhadeep , Mathur Sanjay R. , Murthy Jayathi Y.
Published: August 2012

Radio-frequency microelectromechanical systems (RF MEMS) have wide applicability in contact actuators and capacitive switches. In these devices, the membrane deforms under non-linearly varying electrostatic actuation. It is advantageous to adopt a single comprehensive numerical framework to model these coupled systems. Frequently, the membranes are very thin with aspect ratios as high as 1:500. We model these membranes using the theory of plates and make use of the Mindlin-Reissner plate theory. In this paper, we describe a cell-centered finite volume approach to discretize the governing equations. The discretized equations are linearized completely, and the resulting set of algebraic equations is solved using a biconjugate gradient stabilized (BCGSTAB) solver. Transverse deflection and bending moment distributions are first described for canonical test problems, verifying the accuracy of the method. Results are then presented in this paper for a fixed-fixed MEMS device, modeled as a thin plate, under electrostatic actuation.
An Industrial Robot System for Pocket Machining of Large Size Engine Cylinder Covers
Authors: Noh T. Y. , Jung C. W.
Published: August 2012

Inside of the cylinder cover for a large size engine, several specific areas are required to have endurable property for high temperature, high pressure and corrosion attack. For this purpose, the surface should be machined to the shape of a pocket and covered with inconel overlay welding. This paper represents the machining process using an industrial robot system, which can replace an expensive NC machine for the surface machining process. It also describes that how the robot generates its path from the CAD data and compensates its position with a laser distance sensor. The pocket machining system incorporating an industrial robot was successfully developed and can cover various engine types efficiently in this field.
Developing the Color Full-Scale Schlieren Technique for Flow Visualization
Authors: Chen Chien-Chih , Hung Yu-Cheng , Wang Shun-Chih , Ting Chen-Ching
Published: August 2012

The full-scale schlieren technique was famous and especially developed for flow visualization with large area of test section. This article further presents the color full-scale schlieren technique which captures more colorful images and also promotes the resolution of images. In this work, the developed color full-scale schlieren technique used the light source which penetrates through the linear grating color mask with alternated red, green, and blue colors. The applied light source is made of flat plate and with modular structure which is convenient for varying area of the light source. The width of the grating color lines is 6 mm. The applied area of light source and its test section are 2×2 and 1×1 m2 respectively. In future, this developed color full-scale schlieren technique will be further used for e.g. CO flow visualization during incomplete combustion process of fuel gas. The results in this work show beautiful images and also with expected high sensitivity.
Fabrication and Application of a Chemical Resistant Low-Cost Microdrop Generator
Authors: Kagerer Markus , Rumschoettel Dominik , Irlinger Franz , Lueth Tim C.
Published: August 2012

This paper introduces a chemical resistant piezoelectrically driven microdrop generator which can be fabricated in a cost and time saving manner by using rapid prototyping techniques. Thus it is especially suitable as an experimentation platform. For the adaption of microdrop generators to various fluids, an experimentation platform is needed which allows the rapid change of geometry, dimensions, and material parameters of the microdrop generator. The size of the nozzle, the geometry of the pumping chamber, and the thickness of the used piezo-transducer have to be adaptable to various fluids to achieve drops of the size, speed, and uniformity that are needed. This microdrop generator uses a sandwich structure which consists of a silicon wafer, a Pyrex diaphragm, and a PZT transducer. A pumping chamber is milled into the silicon by laser micromachining; and the Pyrex is anodically bonded on top of the silicon plate to seal off the pumping chamber. The piezo-transducer is then glued to the diaphragm with an epoxy adhesive to obtain a bimorph actuator. When electrically driven, the actuator bends inwards into the pumping chamber which in turn creates a pressure wave inside the chamber that finally leads to the ejection of a drop out of the lateral nozzle. Since only the Pyrex and the silicon are in contact with the fluid the assembly is very resistant to aggressive media like solvents, adhesives, or acids. The thickness of the piezo-actuator can be varied according to the intended application. Depending on the piezoceramic used, the operating temperature is up to 250 °C. Single- and multi-nozzle arrays as well as the integration of a heated fluid reservoir can be realized. The drop volume is set by proper dimensioning of the microdrop generator. Manufacturing, assembly, and interconnection technology of the droplet generator will be described later in this paper. The electro-mechanical behaviour of the droplet generator is analyzed by determining the step response function and by measuring the frequency-dependant impedance. For the first fluidic validation of the experimentation platform, isopropanol is used because of its well known properties. The relationship between drop velocity and drive voltage on the PZT transducer is established. Special attention is paid to the calculation of the microdrop generator material cost which only amounts to $25 for a multi-nozzle array. By using rapid prototyping techniques the microdrop generator is manufactured within 180 min. This shows the potential for a low-cost and rapidly producible experimentation platform.
A Product-Service System for Industrial Waste Heat Recovery Using Mobile Latent Heat Accumulators
Authors: Ko¨ster M. , Sadek T.
Published: August 2012

To operate industrial processes like the generation of hot water and steam or the melting and heat treatment of materials, thermal energy is usually required. In all these processes, a waste of thermal energy occurs, which is referred to as industrial waste heat. In order to reduce the primary energy consumption and environmental impacts due to CO2 emissions, the wasted energy should be recovered efficiently. Different technologies to reuse industrial waste heat for other applications exist. Companies interested in applying these technologies are confronted with risks and uncertainties, such as the lack of knowledge in this field of technology and risks involved with investments in these technologies. Due to these risks and uncertainties, the potential of existing technologies for industrial waste heat recovery is not realized sufficiently. The aim of this article is to discuss a Product-Service System (PSS) that is adequate for a flexible, sustainable and profitable waste heat recovery. This solution is based on the storage, transportation and utilization of industrial waste heat via mobile phase change material devices. Based on the introduction, existing and established concepts for waste heat recovery as well as the theoretical fundamentals of the Product-Service System approach and latent heat accumulators are described. Afterwards, the PSS concept for waste heat utilization is presented. In particular, appropriate business models are introduced for this solution.
Die Wear and Coating Galling in Stamping Advanced High Strength Steels
Authors: Shih Hua-Chu , Shi Ming F.
Published: August 2012

Advanced high strength steels (AHSS) have been widely used in vehicle structural components due to their high strength nature with balanced formability. In a typical application, a zinc coating is often required and applied to AHSS for the purpose of corrosion protection. Due to the high strength nature of AHSS, higher forming forces and binder pressures are also required in stamping AHSS, which often results in coating galling and die wear. The degree of coating galling and die wear depends upon forming process variables such as contact pressure, forming speed, lubrication and die temperatures. In this study, the Bending Under Tension (BUT) tester was used to evaluate the effects of these process variables on coating galling and die wear. Dual phase (DP) 590 and 780 steels with galvanized (GI) and galvannealed (GA) coatings were investigated in the study. The results indicate that GI coatings tend to have better wear resistance than GA coatings. A better surface treated (Thermo-Reactive Diffusion Vanadium Carbide) die material was also identified to decrease coating galling and die wear in stamping AHSS.
The Application of Game Theory to Thermoeconomics
Authors: Layton Bradley
Published: August 2012

Last year, we proposed a relationship between physical entropy, S and abstract, yet quantifiable information, I, where entropy has units of J K−1 and information has units of bits (Layton, 2010). Therein, we proposed the relation ΔS = αI, where ΔS = Smax – Smin, with Smax representing the maximum entropy generation rate of a given system, Smin representing the reduction of internal entropy of the system for a given cycle or process, and I representing the information required to perform the cycle or process. The newly introduced coefficient, α with units of J K−1 b−1 was introduced to relate a system’s ability to partition entropy via its inherent information processing capabilities (Turing, 1948). Herein we further develop this equation in an engineering context and explore the social implications of energy conservation through a lens of game theory, concluding that “sustainable” practices, rather than extending the horizon when we will consume the last of the exhaustible fuels, actually have no effect on the point in time at which fossil fuels become exhausted.
Diagnosis of Breast Tumor Using 2D and 3D Ultrasound Images
Authors: Han Yougun , Kim Dong-Woo , Zhao Boxin , Kwon H. J.
Published: August 2012

DIC and DVC algorithms combined with smoothing algorithm were applied to ultrasound B mode images to generate 2D and 3D elastograms. The DIC based elastograms have better accuracy than conventional time-gradient based elastograms, and can estimate the size and the relative elastic modulus of the inclusion with a reasonable accurately. The study shows the potential to apply DIC and DVC based elastograms to the in-vivo diagnosis of pathological tissue within the body, and to provide new information that is related to tissue structure and/or pathology.
Aqua-Ammonia as an Environmentally Acceptable Low Temperature Brine
Authors: Kornhauser Alan A.
Published: August 2012

In many industrial processes, cooling with brines is preferable to cooling with an evaporating refrigerant. For medium and high temperatures (above about −35°C/−30°F), aqueous solutions of calcium chloride, sodium chloride, ethylene glycol, propylene glycol, and methanol have typically been used. For very low temperatures (down to about −80°C/-110°F) halocarbon refrigerants methylene chloride and trichloroethylene have generally been used. In recent years, both methylene chloride and trichloroethylene have come under increasingly strict regulation because of their toxicity. While many plants continue to use these brines, most are searching for alternates. This study was begun in response to the needs of a plant that was replacing methylene chloride with aqueous calcium chloride. The high viscosity of the calcium chloride brine caused design and operational problems. The above-mentioned brines, as well as aqua-ammonia, polydimethylsiloxane, and d-limonene, were compared for cost, toxicity, flammability, environmental safety, and energy efficiency. The energy efficiency comparison included comparisons of heat transfer coefficient, mass flow rate, volume flow rate, frictional pressure drop, inertial pressure drop, and pumping power. The comparisons indicated that aqua-ammonia was the best choice as a replacement for methylene chloride and trichloroethylene in some temperature ranges.
Electrical Conductivity and Elastic Properties of Carbon Nanotube Reinforced Polycarbonate Nanocomposites
Authors: Ngabonziza Yves , Li Jackie
Published: August 2012

In the past years, carbon nanotubes and their composites have been intensively studied due to their extremely high strength and high electrical and thermal conductivities. However, to be able to use CNT-reinforced composites as structural materials in real applications, more cost-efficient processing methods should be adopted and the properties of such nanocomposites need to be further analyzed. Here we investigate the electrical and elastic properties of multi-walled carbon nanotubes (MWCNT) reinforced polycarbonate (PC) nanocomposites produced by injection molding which has been widely used in industrial plastic production. Nanocomposite samples with MWCNT ranging from 0 to 7wt% were tested for both electrical conductivity using a 2-probe measurement and mechanical properties under tensile loading. It has been found that the electrical conductivity depends on both injection velocity and the CNT content while the elastic properties of the nanocomposites only depend on the CNT content. Besides the experimental testing, a percolation theory and micromechanics models have been applied to determine the electrical conductivity percolation threshold and the effective elastic modulus of the nanocomposites in terms of CNT contents. The results are compared with our experimental data. It shows that a percolation threshold is around 1.8wt% of MWCNT. The evaluation of elastic properties using micromechanics models not only indicates the influence of MWCNT on elastic properties but also the presence of an interphase between the CNT and PC matrix.
Advanced Exergoeconomic Analysis of a Refrigeration Machine: Part 2—Improvement
Authors: Morosuk T. , Tsatsaronis G.
Published: August 2012

In the first part of the paper, the advanced exergy-based analyses are applied to an air refrigeration machine. In this part, we demonstrate that the information obtained in the first part can be used to modify the values of the decision variables to reduce the cost of the final product (cold) of the overall system.
Human Powered Press for Raw Earth Blocks
Authors: Ferraresi C. , Franco W. , Quaglia G.
Published: August 2012

This paper concerns the study and design of a human powered press for raw earth compressed blocks. The first section considers a commercial model of such a press, in order to emphasize all necessary operations for the production of raw earth bricks, as well as the functional characteristics required to realize blocks of good quality. In particular, a kinematic analysis of the cam-roller mechanism used in the bi-directional compression phase is presented. In the second section a new solution of bi-directional press is proposed, aimed at simplifying the machine architecture, reducing costs and achieving an optimized functionality.
On the Thermal Characteristics of Two-Phase, Liquid-Liquid, Non-Boiling Droplet Flow in Minichannels
Authors: Mac Giolla Eain Marc , Egan Vanessa , Punch Jeff
Published: August 2012

Two-phase flow regimes offer numerous advantages over traditional single phase flows, resulting in a wide variety of uses in diverse applications such as electronics cooling, heat exchange systems, pharmacology and biological micro-fluidics. This paper experimentally investigates the enhanced heat transfer rates attainable with two-phase liquid-liquid non-boiling droplet flow. A custom experimental facility was constructed, allowing the flow to be analysed in a minichannel geometry subjected to a constant heat flux boundary condition. Parameters of Reynolds number, Capillary number, droplet length and droplet spacing were varied during the course of the experimentation. The experiments were conducted over the Reynolds number range of 46 ≤ Re ≤ 71.8 and a Capillary number range of 0.00849 ≤ Ca ≤ 0.0102. The flow passed through a capillary of 1.5mm internal diameter and 0.25mm wall thickness. Local Nusselt numbers were obtained at the entrance region through the use of infrared thermography. Enhancements of 144% over fully developed Poiseuille flow were encountered. The findings of this paper highlight the thermal characteristics of two-phase liquid-liquid flow regimes and are of practical relevance to applications in both the thermal management and biological micro-fluidics industries.
A Case Study of Using Capstone Design as Basis for Curriculum-Wide Project-Based Learning
Authors: Hyman Barry , Khanna Sanjeev , Lin Yuyi , Borgford-Parnell Jim
Published: August 2012

This paper describes an NSF funded project in the Mechanical and Aerospace Engineering (MAE) Department at the University of Missouri. A primary goal of this project is to systematically increase project-based learning (PBL) experiences throughout the MAE curriculum. To accomplish this goal, recent capstone design projects that need further refinements serve as the basis for PBL activities throughout the MAE curriculum. A major tool for facilitating these refinement efforts is a new senior/graduate Design Management course in which each student in this course learns how to plan and manage design projects. These students then implement their learning by serving as project team managers in the courses in which the refinement activities are being conducted. This paper provides a detailed case study of five refinements to one capstone design that took place in four different MAE courses during the Spring 2011 semester. The paper describes a Fall 2009 capstone project that consisted of designing a portable wood chipper. The student design was very promising, leading to a chipper with significantly greater chipping capacity than commercially available chippers of the same size and weight. However, several faculty members reviewed the results and identified additional opportunities for refining the design. This paper describes activities during Spring 2011 when students in four different MAE courses developed refinements to the original design. The roles of the Design Management students in these activities are discussed. The paper also includes a discussion of the methods and findings of the formative assessment process, including interviews with, and surveys of, faculty and students.
Tribological Behavior of High Density Polyethylene Nanocomposites With Silane Treated Carbon Nanofibers
Authors: Xu Songbo , Akchurin Aydar , Tangpong X. W. , Akhatov Iskander S. , Liu Tian , Wood Weston , Zhong Wei-Hong
Published: August 2012

New applications of carbon-based materials have been continuously developed in recent years. Carbon Nanofibers (CNFs) with silane coatings were added into high density polyethylene (HDPE) to improve the tribological properties of the nanocomposite material for biomedical applications. The nanocomposites were fabricated with various weight percentages of carbon nanofibers (0.5%, 1%, 3%) that were treated with different silane coating thicknesses (2.8nm, 46nm) through melt-mixing and compressive processing. The wear and friction tests were performed on a pin-on-disc tribometer under phosphate buffered saline lubricated condition. Compared with the pure HDPE, the friction coefficients of the nanocomposites were reduced dramatically and their wear resistance properties were also improved. Micro-hardness measurements of the nanocomposites were carried out and CNFs were found to be capable of improving the material’s micro-hardness effectively. The effects of concentration and silane coating thickness of CNFs on the tribological properties of the resulting nanocomposites were analyzed and the wear mechanism of the CNF/HDPE nanocomposites was discussed.
Experimental Modal Analysis of the Advanced Combat Helmet
Authors: Medda Alessio , Shridharani Jay , Bass Cameron D. , Chancey Valeta Carol
Published: August 2012

In this work we present a study of the characterization of an Advanced Combat Helmet (ACH) using experimental modal analysis techniques. A medium-sized helmet was impacted at different location and the vibration response was used to estimate a global frequency model. This was achieved using the modal parameters of the local models obtained for a specific input-output location and combining them in a global model. The estimation of the frequency model was done using well-established least squares techniques, while the contribution of measurement noise in input and output was considered.
Imperfection Analysis of a Bistable Shell
Authors: Ford K. R. , Brake M. R. , VanGoethem D. J. , Cobert A.
Published: August 2012

Bistable compliant flexures serve as mechanical memory and threshold devices for switches and sensors. One class of bistable compliant flexures is the annular, spherical shell, termed a bistable snap disc. These structures offer flexibility for mechanical memory and threshold devices because large changes in buckling loads can be achieved without significantly modifying the geometry. The sensitivity of these bistable snap discs to imperfections, however, prevents them from withstanding pre-buckling loads predicted by idealized models. A method to incorporate geometric imperfections into an existing finite element mesh of the idealized geometry using a set of orthonormal polynomials, specifically the annular Zernike polynomials, is proposed in this paper. A sensitivity analysis of five terms from the Zernike polynomial expansion is performed with a geometrically nonlinear finite element model to identify their effect on buckling, snap-through, and quasi-static stability. The effects of the perturbations are established by identifying key points on a force-deflection curve and potential energy curve. Results show that the geometric perturbations may account for the discrepancy in buckling between the idealized model and experiments. Error between the experiments and the model with geometric perturbations persist because the actual imperfections of the discs used in the experiments have not yet been characterized, and the finite element model does not account for non-homogeneous material properties and residual stresses.
Stress Analysis of Functionally Graded Thick-Cylinders Subjected to Mechanical and Thermal Loads
Authors: Ahmed Jasem A. , Wahab M. A.
Published: August 2012

Thermo-mechanical stresses in functionally graded (FG) thick-walled cylindrical vessels are investigated in this paper. The cylinder is assumed to be made of a functionally graded material (FGM) with varying material properties in the radial direction. The modulus of elasticity, thermal conductivity, and coefficient of thermal expansion are expressed using power laws. The hollow cylinder is subjected to axisymmetric mechanical and thermal loading. Governing equations are developed for the desired configuration by using equations of equilibrium, stain-displacement relation, and Hooke’s law. A computer program is written in Maple −14 to show the effect of the power indices on the radial, tangential, axial, and Von-Mises stress distributions. The results are compared from the work available in the existing literature. Results show that the Von-Mises stress can be relaxed for specific gradients. Thus, appropriate gradients can be used to make functionally graded cylindrical vessels to maintain structural integrity when subjected to severe mechanical and thermal loads.
Estimation of Surface Roughness and Elastic Modulus Degradation of Nanoindented Surfaces Using Finite Element Method
Authors: Paneeru Niranjan , Moradi Rasoul , Asmatulu Ramazan , Lankarani Hamid M.
Published: August 2012

The surface roughness influences the mechanical properties of materials, such as elastic modulus, hardness, tensile and yield strengths and ductility. Previous studies have shown the behavior of hardness changes by surface roughness of the material using spherical indenters on the spherical surfaces. The effect of the elastic modulus changes with the roughness, but this has not been truly investigated. The main purpose of this study is to develop a computational methodology to estimate the behavior of elastic modulus and hardness of the material on different surfaces. The models used in this study are developed using the Msc Patran and simulated by a finite element analysis code LS-DYNA. In this study, four models have been developed with different surfaces to estimate the behavior of elastic modulus and hardness by nano-indentation using a sharp tip conical indenter. The change in modulus and roughness are estimated by nano-indentation using the Oliver and Pharr’s theory. The penetration depths are normalized as the change in roughness scale on the material and also as the change in radius of the indenter. The study shows that as the roughness of a surface increases, the hardness increases from the actual hardness at various depths, and it carries on a first order model of roughness with a fractal surface material by nano-indentation method. Not only the roughness influences the material properties but also when the material has damage, it also influences the material properties. For this, the models are developed by placing some voids in the material, and the behavior of elastic modulus and hardness of material with and without damage are estimated. Finally, the penetration depth estimated from nano-indentation is compared using the classical macro-scale Hertzian theory, and interestingly found that this theory can also be used for nano-indentation of metals and solids. The results from this research can be utilized to estimate roughness and modulus degradation caused by nano-indentation.
Simulation of Effects of the Saffman Force and the Magnus Force on Sand Saltation in Turbulent Flow
Authors: Zheng Z. Charlie , Zou Xueyong , Yang Xiaofan , Cheng Hong
Published: August 2012

The effects of both the Saffman force and Magnus force on sand saltation are investigated. Turbulent flows in a channel and over a barchans dune are considered with sand particles injected into the flow. The results show that both of the forces increase the height and skipping distance of sand saltation, with the Magnus force giving more significant effect on the height. These forces can also increase the sand settling at the lee side of the barchans dune.
Field Coupling and Stress Mitigation in Electrically Conductive Composites
Authors: Barakati A. , Zhupanska O. I.
Published: August 2012

The present paper studies the effects of stress mitigation in a mechanically loaded electrically conductive composite by application of an electromagnetic field. Governing equations are derived for a long transversely isotropic current-carrying thin plate subjected to an impact-like mechanical load and immersed in a magnetic field. The numerical solution procedure consists of a sequential application of time and spatial integration, quasi-linearization and stable orthonormalization. The numerical results show that the stresses and transverse vibrations of the impacted plate are reduced in the presence of the pulsed current and external magnetic field. Furthermore, the magnitude and direction of the electric current and magnetic induction have significant effects on the response of the plate. This study suggests that there is an optimum for the electromagnetic load combination in improvement of the impact response.
Nitrogen Diluted Jet Flames in the Presence of Coflowing Air
Authors: Kribs James D. , Hasan Tamir S. , Lyons Kevin M.
Published: August 2012

The purpose of this study is to observe methane jet flames under varying levels of nitrogen dilution and coflowing air. The jet flames were examined in order to determine the conditions for which liftoff and blowout occur under conditions that strain the flame. Methane flow rates were varied, corresponding to intermediate lifted positions to blowout. A sequence of images were taken at each level of dilution and coflow, and were used to determine the lowest radial and axial position of the flammability limit. These flammability regions were compared to the lean flammability limit. It was observed that flame shape and liftoff were considerably more influenced by the effects of the coflowing air compared to the presence of the diluents, and that flames under coflow lost the trailing diffusion flame earlier, which has been shown to be a marker for flame blowout.
Design Experience in a Sophomore Mechanics and Machines Course
Authors: Mokhtar Wael
Published: August 2012

Design experience was introduced in a Mechanics and Machines sophomore course. The objective was to support the content of the course and provide the students with some of the design skills. The students were asked to design an over head crane. Several “real-world” practical components were used in the project such as a customer, a request of a profession quote, update presentations, decision making tools, cost analysis, benchmarking, user manual development and a final professional report. The details of the project are presented and samples from the students’ work are discussed. The project was used in several offerings of the course and showed success.
Development of a Failure Locus for a 3-Dimensional Anterior Crutiate Ligament: A Finite Element Analysis
Authors: Orsi A. , Yang N. H. , Vaziri A. , Canavan P. K. , Hashemi H. N.
Published: August 2012

This study investigated movement combinations which may cause injury to the anterior cruciate ligament (ACL). A 3-Dimensional finite element knee joint model, including bones and ligament bundles, was developed. Bone was modeled as rigid, and a transversely isotropic material was applied to the ligament structures. This study incorporates a novel approach for developing bundle specific prestrain within the ligament structures. The bundles were stretched from their zero load lengths to their reference lengths, producing a strain field mimicking in vivo conditions at full knee extension. A failure locus was created by performing multiple knee joint motion combination simulations until ligament failure. The locus shows which movement combinations of internal/external femoral rotation and varus/valgus angle cause failure within the ACL bundles at 25° of knee flexion. The 3D model provided improved accuracy for locating bundle ruptures. By monitoring stresses and strains within the ligament bundles during knee joint orientation simulations, ruptures were virtually diagnosed. The relationship between knee joint orientation and ligament rupture provides a spectrum for the propensity of ACL injury. The results highlight femoral external rotation relative to the tibia as an important factor related to ACL injury. The results also show the posterolateral bundle to be more susceptible to rupture than the anteromedial bundle. These results have various clinical applications. In sports where ACL injuries are prevalent, training programs can be adapted to address the avoidance of harmful knee orientations. Monitoring bundle rupture locations also increases insight for practitioners in identifying more precise injury mechanisms.
Design of an Air Pressure-Assisted Centrifugal Dewatering Method for Fine Particle Suspensions
Authors: Asmatulu R.
Published: August 2012

An air pressure-assisted centrifugal dewatering unit was designed and fabricated for the dewatering of fine particles (−150 μm), such as clay, silica, and talc. The aim of this filtration unit is to increase the filtration rate during the drainage cycle and, hence produce drier filter cakes, which in turn could reduce the cost and emission problems of thermal dryers in the preparation plants. Several dewatering parameters, including applied pressure, centrifugal force (G-force), spin time, and cake thickness were tested to optimize the processing conditions. Test results showed that at higher air pressure and centrifugal force, the cake moisture reduction was more than 60% depending on the experimental conditions. As a result, it can be concluded that the novel filtration unit effectively works on the dewatering of fine particles and can open up new opportunities in the field.
Development of Low Pressure Filter Testing Vessel and Analysis of Electrospun Nanofiber Membranes for Water Treatment
Authors: Ceylan M. , Nilsen K. , Misak H. , Asmatulu R.
Published: August 2012

A low-pressure filtration unit incorporated with polymeric electrospun polyvinyl chloride (PVC) fiber membranes was designed and fabricated for the treatment of waste water in order to improve its quality. This custom-made pressure filter was designed according to the American Society of Mechanical Engineers (ASME) Boiler and Pressure Vessel Code (BPVC). A scanning electron microscope (SEM) was used to characterize the electrospun membranes. In order to increase the hydrophilicity and filtration rates of PVC membranes, a lower dosage of poly (ethylene oxide) was added to the PVC solution prior to the electrospinning process. The filter was found to be well suited for the reduction of larger suspended solids, turbidity, and odor. It was demonstrated that this type of filtration membrane could be manufactured at a lower cost and not require electricity or any other external power source to achieve high flow rates. This technology could even be used to enhance the quality of tap water in many places, such as Africa. Another application could be a pre-filtration of reverse osmosis (RO) or other ultrafine filtration systems, to increase the life of the primary filter while decreasing fouling and maintenance.
Determination of Optimum Values of Control Parameters to Reduce Laser Speckle Noise for Projection Moire´ System
Authors: Kang Sungbum , Gong Jie , Ume I. Charles
Published: August 2012

Projection moire´ technique using laser interferometry to generate grating patterns is one of the major techniques for out-of-plane displacement or warpage measurement of electronic packaging devices. Laser speckle is one of the most crucial sources of noise that increase measurement error and decrease repeatability of projection moire´ systems. The aim of this work is to reduce the laser speckle noise by optimizing the noise control parameters (laser power, camera exposure and camera gain) to minimize the measurement error and maximize the repeatability of the projection moire´ system. Taguchi’s design experimental method is used to formulate the experimental layout, to investigate the effect of the each control parameter on the measurement error and repeatability, and to determine the best possible parameter levels. Regression analysis is employed to precisely find the optimum values of the each control parameter. The validation test shows that the approach using Taguchi method and regression analysis is well established to optimize the noise control parameters of the projection moire´ system.
Rotation of Material Axes Effects on Free Bending Vibrations Response of Composite Mindlin Base Plates or Panels Stiffened by Three Bonded Plate Strips
Authors: Yuceoglu U. , Javanshir J. , Farsadi T. , Gu¨vendik O¨.
Published: August 2012

In the present study, the rotation of material axes on the free bending vibrations response of a certain type of composite “Bonded and Stiffened System” is theoretically analyzed and numerically solved with some numerical results. The composite “Bonded and Stiffened System” is composed of a “Mindlin Base Plate or Panel” reinforced by three “Bonded Stiffening Plate Strips”. In the analysis, the 90° rotation effects of the material axes on the natural frequencies and the mode shapes of the entire “System” are investigated. The aforementioned “Bonded and Stiffened System” is considered in terms of the “System.1” and the “System.2”. In the “System.1”, the material axes of the “Base Plate” are rotated 90° (about z-axis), while there is no change in the material axes of the “Bonded Plate Strips”. In the “System.2”, there is no change in the material directions of the “Base Plate”, while the material axes of the “Bonded Plate Strips” are rotated 90° degrees. The “Base Plate or Panel” and the three “Bonded Plate Strips” are assumed to be dissimilar “Orthotropic Mindlin Plates”. The in-between, relatively very thin, linearly elastic adhesive layers are considered with different material characteristics. All “Mindlin Plate Elements” of both “Systems.1 and 2” are included in the analysis with the transverse (or bending) moments of inertia and rotary moments of inertia. The dynamic equations of the “Mindlin Plate Elements” and the in-between adhesive layer expressions (with the transverse normal and shear stresses) are combined togather. After some algebraic manipulations and combinations, they are eventually reduced to a set of the “Governing System of the First Order O.D.E’s” in compact matrix forms with the “state vectors” for each case of the “System.1” and “System.2”. The aforementioned “Governing Equations” facilitate direct application of the present method of solution that is the “Modified Transfer Matrix Method (MTMM) (with Interpolation Polynomials)”. The “Governing Equations” are numerically Integrated by means of the “ (MTMM) (with Interpolation Polynomials)”. The natural frequencies and the mode shapes of the “Systems.1 and 2” are computed and graphically presented for some “Support Conditions” of the “Systems” under consideration. The comparison of the numerical results led to some important conclusions.
Development of Voice-Coil Micro-Actuator for 3-D Virtual Tactile Displays
Authors: Szabo Zoltan , Ganji Mahdi , Enikov Eniko T.
Published: August 2012

An electromagnetic micro-actuator operating on the principle of voice-coil actuators is presented. Using finite element analysis of several conceptual designs of actuators [1–3], it was established that the voice-coil type device (where the coil is the moving part) has most beneficial characteristics for the envisioned application. These include sufficient force over a relatively large distance, allowing tactile stimulation of surfaces with irregular shape, fast response, and small footprint that matches the density of the tactile sensory neurons in the finger. Finite element analysis based on ANSYS was used to determine the dimensions of the components of the actuator. In comparison to earlier designs [3–5], this novel device has smaller sizes (2.28 mm in diameter and 7 mm in length), which makes it suitable for use in an array to be worn on the fingertip. Based on the static measurements of a test prototype, it is estimated, that the micro-actuator can produce at least 26 mN of repulsive force on the fingertip over a stroke of 2100 μm with a peak force of 34 mN. The driving circuit operates with 13.5V and generates a vibration frequency of up to 265 Hz without significant change of the force-displacement characteristics. In the higher frequency range (above 100 Hz) the actuator provides at least 15 mN of force over a stroke of 2300 μm, and a peak force of 21mN. The perceivability of the device on human fingertip approves the expectations drawn from the fact that all of the above parameters meet the required values of the thresholds of the human perception known from [4] and [5]. Due to its increased stroke, the voice-coil micro-actuator proved to be very suitable for the envisioned application allowing contact with the curved surface of the fingertip.
Numerical Modeling of Co-Firing Chunk Coal and Oat Hulls in a Stoker Boiler
Authors: Zhang Xinhui , Ghamari Mohsen , Ratner Albert
Published: August 2012

The current study presents a numerical study of co-firing chunk coal and one kind of light weight biomass, oat hulls, in a stoker boiler. First, a standard combustion model was applied to simulate coal combustion in a real size three dimensional boiler; the results were compared with the temperatures measured at different locations of the stoker boiler to assess the accuracy of heat sink and heat transfer model. Once a good accuracy was achieved, a devolatilization model for oat hulls was derived from experimental data and was matched with this combustion model to simulate combustion in a co-firing stoker boiler. The results showed that light biomass burns in suspension, similar to pulverized coal by following the air flow. Also, the peak temperature inside the furnace inversely varies with the increase of co-firing percentage of oat hulls. This numerical study reveals thermal and economic potential of using unprocessed light weight biomass on the existing combustion facility.
High Temperature Fluidized Bed Reactor Kinetics With Sintering Inhibitors for Iron Oxidation
Authors: Al-Raqom F. , Klausner J. F. , Hahn D. , Petrasch J. , Sherif S. A.
Published: August 2012

High purity hydrogen is produced through a thermochemical water splitting process that utilizes iron reduction-oxidation (redox) reactions. An iron powder bed is fluidized to improve heat and mass transfer thus improving the reaction kinetics. Inert additives which act as sintering inhibitors, such as silica (SiO2) and zirconia (ZrO2), are added to the iron powder, and their effectiveness in inhibiting sintering in the oxidation step is evaluated. The influence of particle size, composition, mass fraction and bed temperature on reaction kinetics is investigated. Incorporation of zirconia in the powder bed is done by mixing it with iron powder or by coating the iron particles with a mixture of 1–3 μm and 44 μm zirconia particles. Two different batches of silica are used for blending with iron powder. The silica powder batches include particle diameters ranging from 0–45 μm and 200–300 μm. The mixing ratios of silica to iron are 0.33, 0.5, 0.67 and 0.75 by apparent volume. Experimental studies are conducted in a bench scale experimental fluidized bed reactor at bed temperatures of 450, 550, 650, 750 and 850 °C. It is verified that increasing the bed temperature and the steam residence time increases the hydrogen yield. Increasing the iron particle size reduces the specific surface area and reduces the hydrogen yield. It has been found that sintering can be completely inhibited by mixing iron with 0–45 μm silica powder and maintaining the reaction temperature below 650 °C.
A Lab-on-a-Chip Device Using a Dielectrophoresis-Aligned Carbon Nanotube Sensor Array
Authors: Li Pengfei , Lei Nan , Xu Jie , Xue Wei
Published: August 2012

Here we report the design, fabrication, and characterization of a lab-on-a-chip device using a nanotube-based sensor array. The microfluidic components are composed of an ultraviolet (UV) light-defined, cross-linked SU-8 microchannel and a polydimethylsiloxane (PDMS) top cover. The hybrid microfluidic structure provides a fully sealed microchannel, well-aligned features, and precisely positioned nanosensors. Well-organized single-walled carbon nanotube (SWNT) thin films are deposited and aligned across the electrodes on a silicon substrate with dielectrophoresis. The assembly of SWNTs is carried out in a sealed microchannel. The SWNT devices are configured as two-terminal resistor-type sensors with the metal electrodes as the probing pads and the dielectrophoretically captured SWNTs as the sensing elements. The SWNT devices are used as integrated flow sensors to monitor the flow rate in the microchannel. In addition, when exposed to aqueous solutions with various pH values, these sensors change their resistance accordingly and demonstrate high sensitivity towards pH solutions.
Fracture Behavior of Long Glass Fiber Reinforced PP Sheets With Hole
Authors: Sakai Hiroshi , Thitithanasarn Smith , Uawongsuwan Putinun , Yang Yuqiu , Hamada Hiroyuki
Published: August 2012

Recently, owning to the increasing concerns on the environment, lightweight materials representative by composite are being considered to be used in primary structure components in particular in vehicle instead of metal. In order to enhance the mechanical property in particularly tensile property, at current study, stampable sheets (glass mat which were fabricated by punch knitted technology) were adopt to make glass mat reinforced thermoplastic PP (GMT). In the paper, three kinds of specimens including two GMT which have glass fiber weight percent 40 and 20 wt% respectively and a LFT (normal long fiber reinforced thermoplastics PP) which has glass fiber 40wt% were fabricated and tensile tested. The mean fiber length of GMT and LFT were 6.67 and 1.37 mm, respectively. For tensile test, it was observed that the modulus of 40GMT and 40LFT were similar. However, it was found that 40GMT specimens have better tensile strength than 40LFT specimens. In the case of different glass fiber content, 40GMT had more than two times higher value than 20GMT in both tensile modulus and tensile strength. Referring to the effect of hole on the tensile property of GMT and LFT, it was found that the notched tensile strength of both GMT and LFT decrease when W/d equal to 2.0. On the other hand, for W/d equal to 2.5 and 3.0 have no effect to tensile strength.