Engineering Commons^™

The Design Of Adjustable Spherical Mechanisms Using Plane-To-Sphere And Sphere-To-Plane Projections, Wen-Tzong Lee

Dissertations

The spherical mechanism is a particular type of spatial mechanism. Due to the orientation of its joint axes and the curvature of its links, the workspaces of spherical mechanisms (whether line segments, closed loops or area regions) are spherical in curvature. This characteristic of spherical mechanisms makes them quite effective and practical in motion path and function generation applications requiring spherical rigid body kinematics.

Although there are design methods available for spherical mechanisms, most of these methods do not consider the design of a single adjustable spherical mechanism. With an adjustable spherical mechanism, the user could for example, relocate the …

3-D Numerical Simulation Of Reactive Extrusion And Its Application To Polymerization Of Ε-Caprolactone In Co-Rotating Twin-Screw Extruders, Linjie Zhu

Dissertations

A 3-D numerical simulation model was proposed to predict the polymerization of ε-caprolactone in fully-filled conveying elements and kneading blocks of co-rotating twin-screw extruders, in which the kinetics equation for polymerization is coupled with continuity equation, momentum equation, and energy equation. With the 3-D model, parametric studies have been carried out to investigate the effects of screw configurations, screw diameter, operational conditions, values of heat from reaction, initiator concentration, and heat transfer conditions at barrel surface upon the polymerization progress. Two simulation models for the polymerization in the partially-filled channels were developed based on the conveying mechanisms of the reaction …

Modeling And Control Of Surface Micromachined Thermal Actuators, Robert K. Messenger

Theses and Dissertations

A model that accurately describes the transient and steady-state response of thermal microactuators is desirable to provide guidance for design and operation. However, modeling the full response of thermal actuators is challenging due to the temperature-dependent material properties and nonlinear deformations that must be included to obtain accurate results. To meet these challenges a three-dimensional multi-physics nonlinear finite-element model was developed using commercial code. The Thermomechanical Inplane Microactuator (TIM) was chosen as a candidate application to validate the model. TIMs were fabricated using the SUMMiT V™ process and their response was measured using a high-speed camera. The TIMs were modeled …

Optimizing Manufactured Housing Energy Use, Florida Solar Energy Center, Mark Mcginley

FSEC Energy Research Center®

In partnership with the Florida Solar Energy Center (FSEC), two manufactured homes were located on North Carolina A&T State University's campus in Greensboro, NC and used in a side-by-side energy consumption comparison. One of the homes was built to the basic HUD code standard and the other was constructed with features expected to produce a home that was 50% more energy efficient.

FSEC and NCATSU began monitoring energy performance in both homes. In addition, the performance of each unit was evaluated using a DOE2 based computer energy analysis program developed by FSEC. A comparison of the performance of the units …

Combining Systematic Layout Planning And Computer Simulation In The Design Of Manufacturing Facilities, Akintoye M. Akinyoade

All-Inclusive List of Electronic Theses and Dissertations

In this study, the systematic layout planning (SLP) and computer simulation were combined to improve the layout design of a manufacturing facility using a case study.

Cavitation Effects On The Stability Of A Submerged Journal Bearing, Jerzy T. Sawicki, T. V. V. L. N. Rao

Mechanical Engineering Faculty Publications

A computational procedure for the mechanism of shear between the liquid sublayer and air cavity in the cavitation zone of a submerged journal bearing is presented here. Using the mass conservation principle, Elrod's universal equation is modified to take into consideration the shear of the air cavity in the cavitation region. Results of steady state and transient response for the submerged journal bearing using the present approach are compared with the universal equation based on the striated flow in the cavitation region. At steady state, the angular extent of cavitation region predicted by the present approach is higher than that …

Nebraska Summary S466: Massey Ferguson 6480 Diesel 32-Speed, Nebraska Tractor Test Lab

Nebraska Tractor Tests

No abstract provided.

Foot And Ankle Forces During An Automobile Collision: The Influence Of Muscles, Elizabeth C. Hardin, Anne Su, Antonie J. Van Den Bogert

Mechanical Engineering Faculty Publications

Muscles have a potentially important effect on lower extremity injuries during an automobile collision. Computational modeling can be a powerful tool to predict these effects and develop protective interventions. Our purpose was to determine how muscles influence peak foot and ankle forces during an automobile collision. A 2-D bilateral musculoskeletal model was constructed with seven segments. Six muscle groups were included in the right lower extremity, each represented by a Hill muscle model. Vehicle deceleration data were applied as input and the resulting movements were simulated. Three models were evaluated: no muscles (NM), minimal muscle activation at a brake pedal …

Design And Simulation Of An Induction Skull Melting System, Taide Tan

UNLV Theses, Dissertations, Professional Papers, and Capstones

Incorporating volatile actinides, mainly americium into a metallic fuel pin (MFP) has been a serious problem due to americium’s high vapor pressure. An Induction Skull Melting (ISM) system was identified by Argonne National Laboratory (ANL) as a potential furnace design to cast MFPs. Through the development of the ISM system, the nuclear waste feedstock can be melted and injected into the mold for fabricating MFPs in the advanced nuclear fuel cycles. The main phenomena in this system include: induction melting process, casting process and mass transfer process of americium. Issues related to ISM system design for casting MFPs are discussed …

Adaptive Optimal Control Design For Stable Vibration Attenuation Of Active Constrained Layer Damping Beam Structure, Tatyana G. Korotkova-Egan

Theses and Dissertations - UTB/UTPA

Vibration suppression using active constrained layer damping (ACLD) has proven to be an invaluable means for improving the performance of a wide variety of engineering systems. The ACLD creates the hybrid of active and passive damping, attaining favorably high damping characteristics, while at the same time, combines unattractive attributes of both treatments, such as stability sensitivity. Control efforts are needed to achieve an adequate performance of the structures treated with ACLD. The purpose of this research is to investigate theoretically and numerically the adaptive optimal controller of the constrained layer damped beam system, using the classical three-layered distributed-parameter model that …

Dynamic Mechanical And Thermal Analysis Of Aligned Vapor Grown Carbon Nanofibers Reinforced Polyethylene, Jose Jaime Taha-Tijerina

Theses and Dissertations - UTB/UTPA

Dynamic-mechanical and thermal characterization of aligned vapor grown carbon-nanofibers (VGCNFs)-reinforced high-density polyethylene (HDPE) has been performed. VGCNFs with diameters ranging from 50–200nm were used. Nanofibers were purified to remove amorphous carbon and metal catalyst, resulting in deagglomeration, and creating an open network that allowed polymer infiltration during mixing. High-shear mixing was used to disperse and distribute the nanofibers uniformly within the matrix. Extensional flow at different draw ratios (λ) was used to obtain anisotropic nanoreinforced composite (NC) tapes. Dynamic Mechanical Analysis (DMA) showed a dual increase, in storage and loss modulus, with draw ratio. This behavior is attributed to the …

Numerical Modeling Of Friction Stir Welding: A Comparison Of Alegra And Forge3, Alma H. Oliphant

Theses and Dissertations

The objective of this research was to evaluate the capabilities of ALEGRA, a Sandia National Labs hydrocode, and Forge3, a Transvalor S.A. product, to accurately model the Friction Stir Welding Process. ALEGRA and Forge3 are discussed in light of the inherent challenges of modeling Friction Stir Welding, and a rotational boundary condition is added to ALEGRA. Results are presented from Friction Stir Welding modeling outputs from both ALEGRA and Forge3. ALEGRA is shown to be incapable of modeling the Friction Stir Welding process, in large part due to its focus on shock propagation, which causes extremely small time steps. Forge3 …

Use Of Positron Annihilation Spectroscopy For Stress-Strain Measurements, Ajit K. Roy

Transmutation Sciences Materials (TRP)

The purpose of this collaborative research project involving the University of Nevada Las Vegas (UNLV) and Idaho State University (ISU) is to evaluate the feasibility of determining residual stresses of welded, bent (three-point-bend), and cold-worked engineering materials using a new nondestructive technique based on positron annihilation spectroscopy (PAS). The proposed technique is to use γ-rays from a small MeV electron linear accelerator (Linac) to generate positrons inside the test sample via 2 pair production. This method can be used for materials characterization and investigation of defects in thick samples that usually cannot be accomplished by conventional positron technique or other …

Low Reynolds Number Flow Through Nozzle-Diffuser Elements In Valveless Micropumps, Vishal Singhal, Jayathi Y. Murthy, S V. Garimella

CTRC Research Publications

Flow characteristics of low Reynolds number laminar flow through gradually expanding conical and planar diffusers were investigated. Such diffusers are used in valveless micropumps to effect flow rectification and thus lead to pumping action in one preferential direction. Four different types of diffuser flows are considered: fully developed and thin inlet boundary layer flows through conical and planar diffusers. The results from the numerical analysis have been quantified in terms of pressure loss coefficient. The variation of pressure loss coefficient with diffuser angle is presented for Reynolds numbers of 200, 500 and 1000. The pressure loss coefficients have been used …

Noble Metal Nanostructures Synthesized Inside Mesoporous Nanotemplate Pores, J. Arbiol, E. Rossinyol, A. Cabot, F. Peiro, A. Cornet, J. R. Morante, Fanglin Chen, Meilin Liu

Faculty Publications

Noble metal impregnation has resulted in the inclusion of metal nanostructures within the SBA-15 mesoporous silica hexagonal pores (from nanoclusters to nanowires). A bright-field transmission electron microscopy three-dimensional reconstruction is proposed to analyze the localization of nanostructures within the pores of mesoporous nanotemplates. The method allows corroboration whether the nanostructures are synthesized inside the pores or they are synthesized alternatively on the nanotemplate aggregates exterior surface.

Robust Procedures For Obtaining Assembly Contact State Extremal Configurations, Pan Feng, Joseph M. Schimmels

Mechanical Engineering Faculty Research and Publications

Two important components in the selection of an admittance that facilitates force-guided assembly are the identification of: 1) the set of feasible contact states, and 2) the set of configurations that span each contact state, i.e., the extremal configurations. We present a procedure to automatically generate both sets from CAD models of the assembly parts. In the procedure, all possible combinations of principle contacts are considered when generating hypothesized contact states. The feasibility of each is then evaluated in a genetic algorithm based optimization procedure. The maximum and minimum value of each of the 6 configuration variables spanning each contact …

Gradient-Based Non-Linear Microstructure Design, Brent L. Adams, M. Lyon

Faculty Publications

The support of this research by the Army Research Office is gratefully acknowledged. M. Lyon is supported by a National Science Foundation Graduate Research Fellowship. Fourier analysis is implemented on the orientation distribution of a polycrystalline microstructure. The linearity and convexity of the Fourier space, with respect to orientation, allows one to consider all possible distributions by considering all linear combinations of single-grain orientations. The limits of the Fourier space are therefore defined by the solutions to a set of linear programming problems. A unique approach to the linear programming, similar to the Krylov subspace methods for obtaining solutions to …

A Vector Quantization Method For Nearest Neighbor Classifier Design, Chen-Wen Yen, Chieh-Neng Young, Mark L. Nagurka

Mechanical Engineering Faculty Research and Publications

This paper proposes a nearest neighbor classifier design method based on vector quantization (VQ). By investigating the error distribution pattern of the training set, the VQ technique is applied to generate prototypes incrementally until the desired classification result is reached. Experimental results demonstrate the effectiveness of the method.

Coupled Problem Of Thermoelasticity For Multilayered Spheres With Time-Dependent Boundary Conditions, Zong-Yi Lee

Journal of Marine Science and Technology–Taiwan

This paper deals with quasi-static coupled thermoelastic problems for multilayered spheres. Using the Laplace transform with respect to time, the general solutions of the governing equations are obtained in transform domain. The solution is obtained by using the matrix similarity transformation and inverse Laplace transform. We obtain solutions for the temperature and thermal deformation distributions for a transient state. It is demonstrated that the computational procedures established in this paper are capable of solving the generalized thermoelasticity problem of multilayered spheres.

Numerical Optimization Of Sound Absorption Systems With Constrained Single-Layer Absorber, Ying-Chun Chang, Long-Jyi Yeh, Min-Chie Chiu, Gaung-Jer Lai

Journal of Marine Science and Technology–Taiwan

The thickness and the attached area of the sound absorber are confined in the practical engineering design while the sound absorber is applied inside the machine room to eliminate the reverberant sound energy. The optimization of the shape of the absorber and the quantification of the exact area of the absorber (in order to meet the required value of sound pressure level (SPL) at the concerned receiving point) becomes essential. For purposes stated above, two powerful gradient techniques with a logical control algorithm are applied during the optimization of the sound absorption system. Both the optimization of shape and the …

Effects Of Viscous Shear Stresses On The Squeeze Films Of Porous Parallel Rectangular Plates, Jaw-Ren Lin, Long-Jin Liang, Rong-Fang Lu

Journal of Marine Science and Technology–Taiwan

Considering the effects of viscous shear stresses, a study of squeeze-film behavior between porous parallel plates with finite width is presented. Based upon the Brinkman model (BM), two general coupled Reynolds equations derived for curved surfaces [20] are applied to predict the two-dimensional squeeze-film pressure and thereafter the squeeze-film characteristics. The results show that the BM predicts quite different squeeze-film behaviors to those obtained by using the slip-flow model (SFM) and the Darcy model (DM). Comparing with the SFM, the viscous shear effects provide an increase in the load-carrying capacity and lengthen the response time of finite porous squeeze-film plates. …

The Effects Of Couple Stresses In The Squeeze Film Characteristics Between A Cylinder And A Plane Surface, Jaw-Ren Lin, Won-Hsion Liao, Chi-Ren Hung

Journal of Marine Science and Technology–Taiwan

On the basis of the Stokes micro-continuum theory, the effects of couple stresses resulting from the lubricant blended with various additives upon the squeeze film behavior between a long cylinder and a plane surface are analyzed. Compared to the conventional Newtonianlubricant case, the couple stress effects characterized by the couple stress parameter signify an improvement in the squeeze film characteristics. Increasing values of the couple stress parameter increases the hydrodynamic load-carrying capacity and provides a longer time to prevent cylinder-plane surface contact. The approaching time of the cylinder in reducing the film thickness h m * = 1 to h …

Gas-Diffusion Process In A Tubular Cathode Substrate Of A Sofc, Part Ii: Identification Of Gas-Diffusion Process Using Ac Impedance Method, Kevin Huang

Faculty Publications

The effects of cathodic dc bias, bulk p_O2, and effective O₂ -diffusivity on ac impedance spectra of Siemens Westinghouse Power Corporation’s cathode-supported solid oxide fuel cells were systematically studied over a temperature range of 800 to 1000°C. It was found that the activation process dominated the overall electrode kinetics at 800°C, by which the applied dc bias reduced the electrode resistance considerably. With increasing the temperature to above 900°C, the activation process became effectively activated, leading to a visible arc at the lowest frequency on the impedance spectrum, which is relevant to the pore gas-diffusion process. …

Gas-Diffusion Process In A Tubular Cathode Substrate Of An Sofc, Part I: Theoretical Analysis Of Gas-Diffusion Process Under Cylindrical Coordinate System, Kevin Huang

Faculty Publications

In this the first part of a two-part paper, the gas-diffusion process through a thick and porous tubular cathode substrate of a solid oxide fuel cell-(SOFC) was theoretically analyzed using classic Fick’s diffusion equation under the cylindrical coordinate system. The effects of current density, temperature, oxygen diffusivity or porosity, wall thickness, and bulk p_O2 on the concentration (or pore in this paper) polarization were calculated and are presented graphically. The results clearly show a greater impact on pore polarization by current density, oxygen diffusivity, wall thickness, and bulk p_O2, but not by temperature. In addition, …

Studies On Yba2nbo6 And Yba2cu3-Xnbxoy Buffer Layers, S. Sathiraju, R. Wheeler, Paul N. Barnes, T. L. Peterson, Iman Maartense, A. L. Campbell, N. A. Yust, T. J. Haugan, Q. Jia, Paul Arendt, Sharmila M. Mukhopadhyay, S. Vemulakonda

Mechanical and Materials Engineering Faculty Publications

No abstract provided.

2004 (Spring) Ensi Informer Magazine, Morehead State University. Engineering Sciences Department

ENSI Informer Magazine Archive

The ENSI Informer Magazine published in the spring of 2004.

An Investigation Of Fuel Consumption During The Warm Up Cycle Of A Gasoline Engine Using 87 Octane Ethanol Blended And Unblended Fuel, Michael Aaron Scott

All-Inclusive List of Electronic Theses and Dissertations

This research investigated fuel consumption during the warm up cycle of a gasoline engine using 87-octane gasoline blended with 0%, 10%, and 20% ethanol. The purpose of this research was to determine ifthere is a significant statistical difference in fuel consumption among the ethanol-gasoline blends controlling for temperature. The experiment identified three properties of ethanol blending: (1) energy (fuel) potential, (2) determination of the speed (time intervals) of the energy consumption within the engine, and (3) indirect effects on coolant temperature. The researcher selected the two-way ANOVA (analysis of variance between variables), covariant, and post hoc to analyze the raw …

Fatigue Of Drill Pipes Used In Horizontal Directional Drilling, Feibai Ma

Doctoral Dissertations

Fatigue is the most common cause of mini-HDD drill rod failure. It can occur at stress levels far below the normal operating stress in most drill stem components. Fatigue failures occur because the drill rod, after it has been forced into a curved path, undergoes a cyclic bending stress oscillating from tension to compression in concert with the other stress components caused by torque, thrust, or pullback.

When a rod breaks underground, there is considerable extra cost caused by the delay in “fishing” out the broken rod as well as the cost of replacing the rod. On the other hand, …

Analysis Of Combustion Chamber Design Variables In Planetary Rotary Engine, Sathyanarayanan Arumugam

Masters Theses

This research entails examining the Hopkins Rotor Mechanism (HRM) for the perspective of commercial viability. Factors that were studied herein include basic operating characteristics, combustion effects, dimensional changes and behaviors unique to the HRM that may impose limits to commercial viability were also examined.

To compare specific characteristics of the HRM engine, in a comparable four-stroke mode, hypothetical 200, 400 and 600 cubic centimeter (cc) single cylinder reciprocating engines, each with compression ratio of 10, 15 and 20 were used as a basis for comparison. For similar outputs this resulted in the use of a 100, 200, 300 cc HRM …

Subcooled Pool Boiling Heat Transfer Using R113 On Flat Surface, Kamleshkumar J. Suthar

Masters Theses

Pool boiling experiment was conducted to investigate the effect of subcooling on boiling of R-113 using 25mm effective dia. flat surface copper heater. Pool boiling heat transfer measurements were taken for wide temperature range of 5 - 39^o C subcooling and investigated thoroughly. Variation in value of wall superheat of incipience boiling, from 27 to 34^o C and 7 to 11^o C temperature excursion observed. Noticeable effect of subcooling on boiling heat transfer is observed. Degree of subcooling was maintained constant by regulating pressure and keeping constant fluid temperature for each test run. Tests were conducted by …