Mechanical Engineering Commons^™

Influence Of Flow Baffles On Mixing Of Two Air Streams Flowing In A Mixing Chamber With Dissimilar Temperatures: A Computational Study, Abdulmunam Salem Shaban

Masters Theses

"One of the most important components of heating, ventilation, and air conditioning (HVAC) is an air handling unit (AHU) which is used to condition and mix air that arrives from outside the building (OA) and return air (RA) that exits from the indoor space. Poor mixing between the warm return air and the cold outside air often leads to air stratification in AHU, which results in various problems, such as, nuisance trips of low temperature safety thermostats, freezing of chilled or hot water coils in a stratified subfreezing air stream and loss of control when sensors cannot read the true …

Performance Evaluation Of A Novel Diesel Fuel Air Separation And Filtration System For An Indirect Injection Diesel Engine, Michael Ray Hess

Masters Theses

"The objective of this research was to evaluate an air/fuel separation system known as a Fuel Preporator. The device's efficacy was determined by studying the effect of air entrainment on engine performance and fuel consumption of a General Motors 6.5 L naturally aspirated indirect injection (IDI) diesel engine. A test bed was developed to accommodate the test engine and test methods were adapted from federal regulations for steady-state engine testing (40 CFR 89 Subpart E). Cases of 0%, 5%, 10%, and 20% volumetric air entrainment were investigated for engine operation with and without the Fuel Preporator. Key measured engine performance …

Freeze Extrusion Fabrication Of 13-93 Bioactive Glass Scaffolds For Bone Repair, Nikhil D. Doiphode

Masters Theses

"We have investigated Freeze Extrusion Fabrication (FEF) of 13-93 bioactive glass to fabricate three dimensional scaffolds for bone tissue engineering. Bioactive glass paste was prepared for consistent extrusion through micro-nozzle and controlled porosity scaffolds were fabricated using additive manufacturing FEF. CAD models were prepared for different scaffold designs and computer controlled layer-by-layer deposition of pseudoplastic paste was carried out to in accordance. Liquid nitrogen assisted freezing of pastes was used for the consolidation of deposited layers. Post processing binder burnout and sintering schedules were designed for evaporation of organic binder and densification of glass. Sintering shrinkage was measured, and X-ray …

Implementation Of Integrated Function Structure And Object-Oriented Design Framework, Qiong Gao

Masters Theses

"The function structure method is commonly used in mechanical product design. Although a function structure allows defining all the functions of the components of a product and their interactions, it does not have an effective architecture for the software design of a mechatronic product. An integrated function structure and object-oriented design framework was recently developed to overcome this disadvantage. In this thesis, the implementation of this framework to design several products in different categories, including an inkjet printer, and electric screwdriver and a vacuum cleaner, is discussed. The design results obtained using the new framework are compared to the design …

Finite Element Modeling Of Bird Strikes And Parametric Evaluation Using Design Of Experiments (Doe), Venkata Varaha Raja Naga Prathyush Bheem Reddy

Masters Theses

"One of the major threats to Aviation industry is the in-flight impact of birds. Aircraft windshields are intensively vulnerable to damage and hence need a certification requirement for a proven level of impact resistance. Bird strike experiments are very expensive and henceforth explicit numerical modeling techniques have grown importance. This compilation mainly relies on the theory of hydrodynamic impact and addresses basic shockwave equations. A smooth particle hydrodynamics based approach is chosen and the numerical simulation is carried out using contact-impact coupling algorithm. The simulation is run using the nonlinear explicit finite element code LSDYNA ver.971, developed by Lawrence Livermore …

Characterization Of Electrowetting Processes Through Force Measurements, Nathan B. Crane, Pradeep Mishra, Alex A. Volinsky

Faculty Publications

A new method of characterizing electrowetting is presented in which the forces applied to a modified nanoindenter tip by a test water droplet are measured. A droplet is trapped between the flat nanoindenter tip and the test substrate containing the necessary electrodes. When voltage is applied to the electrodes in the substrate, lateral and normal forces are exerted on the tip and measured by the nanoindenter transducer. Proper selection of the tip geometry permits direct prediction of the resulting in-plane lateral forces using analytical formulas derived from the Young-Lippmann equation. Experimental results show good agreement with both analytical and numerical …

Quantification Of Relativistic Perturbation Forces On Spacecraft Trajectories, Nicholas Palma Mastricola

Dissertations, Master's Theses and Master's Reports - Open

The intent of the work presented in this thesis is to show that relativistic perturbations should be considered in the same manner as well known perturbations currently taken into account in planet-satellite systems. It is also the aim of this research to show that relativistic perturbations are comparable to standard perturbations in speciffc force magnitude and effects. This work would have been regarded as little more then a curiosity to most engineers until recent advancements in space propulsion methods { e.g. the creation of a artiffcial neutron stars, light sails, and continuous propulsion techniques. These cutting-edge technologies have the potential …

Modeling Mechanical Response Of Heterogeneous Materials, Siladitya Pal

Dissertations, Master's Theses and Master's Reports - Open

Heterogeneous materials are ubiquitous in nature and as synthetic materials. These materials provide unique combination of desirable mechanical properties emerging from its heterogeneities at different length scales. Future structural and technological applications will require the development of advanced light weight materials with superior strength and toughness. Cost effective design of the advanced high performance synthetic materials by tailoring their microstructure is the challenge facing the materials design community. Prior knowledge of structure-property relationships for these materials is imperative for optimal design. Thus, understanding such relationships for heterogeneous materials is of primary interest. Furthermore, computational burden is becoming critical concern in …

Energy Harvesting From Body Motion Using Rotational Micro-Generation, Edwar. Romero-Ramirez

Dissertations, Master's Theses and Master's Reports - Open

Autonomous system applications are typically limited by the power supply operational lifetime when battery replacement is difficult or costly. A trade-off between battery size and battery life is usually calculated to determine the device capability and lifespan. As a result, energy harvesting research has gained importance as society searches for alternative energy sources for power generation. For instance, energy harvesting has been a proven alternative for powering solar-based calculators and self-winding wristwatches. Thus, the use of energy harvesting technology can make it possible to assist or replace batteries for portable, wearable, or surgically-implantable autonomous systems. Applications such as cardiac pacemakers …

Structural And Surface Property Characterization Of Titanium Dioxide Nanotubes For Orthopedic Implants, Tolou Shokuhfar

Dissertations, Master's Theses and Master's Reports - Open

This research focused on the to modification of the surface structure of titanium implants with nanostructured morphology of TiO₂ nanotubes and studied the interaction of nanotubes with osteoblast cells to understand the parameters that affect the cell growth. The electrical, mechanical, and structural properties of TiO₂ nanotubes were characterized to establish a better understanding on the properties of such nanoscale morphological structures.

To achieve the objectives of this research work I transformed the titanium and its alloys, either in bulk sheet form, bulk machined form, or thin film deposited on another substrate into a surface of titania nanotubes …

Parametric Combustion Modeling For Ethanol-Gasoline Fuelled Spark Ignition Engines, Yeliana

Dissertations, Master's Theses and Master's Reports - Open

Ethanol-gasoline fuel blends are increasingly being used in spark ignition (SI) engines due to continued growth in renewable fuels as part of a growing renewable portfolio standard (RPS). This leads to the need for a simple and accurate ethanol-gasoline blends combustion model that is applicable to one-dimensional engine simulation.

A parametric combustion model has been developed, integrated into an engine simulation tool, and validated using SI engine experimental data. The parametric combustion model was built inside a user compound in GT-Power. In this model, selected burn durations were computed using correlations as functions of physically based non-dimensional groups that have …

Water Absorption Of Carbon Nano-Fiber Enhanced Polyester/E-Glass Composite Materials, Basil I. Farah, Gail D. Jefferson, Kuang-Ting Hsiao

Early Career Technical Journal (ECTJ)

Proceedings of the ASME Early Career Technical Conference, October 1-2, 2010. Woodruff School of Mechanical Engineering, Georgia Institute of Technology, Atlanta, Georgia

pp. 173-177

Nonparametric Estimation Of Derivatives With Applications, Benjamin Hall

University of Kentucky Doctoral Dissertations

We review several nonparametric regression techniques and discuss their various strengths and weaknesses with an emphasis on derivative estimation and confidence band creation. We develop a generalized C(p) criterion for tuning parameter selection when interest lies in estimating one or more derivatives and the estimator is both linear in the observed responses and self-consistent. We propose a method for constructing simultaneous confidence bands for the mean response and one or more derivatives, where simultaneous now refers both to values of the covariate and to all derivatives under consideration. In addition we generalize the simultaneous confidence bands to account for heteroscedastic …

Laminar-Turbulent Transition For Attached And Separated Flow, Qian Zhang

University of Kentucky Doctoral Dissertations

A major challenge in the design of turbomachinery components for aircraft gas turbine engines is high cycle fatigue failures due to flutter. Of particular concern is the subsonic/transonic stall flutter boundary which occurs at part speed near the stall line. At these operating conditions the incidence angle is large and the relative Mach number is high subsonic or transonic. Viscous effects dominate for high incidence angles.

In order to predict the flutter phenomena, accurate calculation of the steady and unsteady aerodynamic loading on the turbomachinery airfoils is necessary. The development of unsteady aerodynamic models to predict the unsteady forces and …

Engineering Sport Safety: A Study Of Equestrian Cross Country Eventing, Katherine M. Kahmann

University of Kentucky Master's Theses

The sport of equestrian cross country eventing has seen many serious and even fatal injuries due to rotational horse falls in recent years. The sport originally consisted of horse and rider teams jumping stationary, wood fences. However, in a move towards increasing safety for horses and riders, frangible and deformable safety devices have been emerging in the field. This thesis provides an overview of safety designs that are currently available and those that are on the horizon. Also, a path-finder method of evaluating and developing safety fence designs was outlined and applied to two distinct designs, a hinged gate and …

Interfacial Thermal Conductivity Using Multiwall Carbon Nanotubes, Carissa Don Russell

University of Kentucky Master's Theses

Shrinking volume, coupled with higher performance, microprocessors and integrated circuits have led to serious heat dissipation issues. In an effort to mitigate the excessive amounts of waste heat and ensure electronic survivability, heat sinks and spreaders are incorporated into heat generating device structures. This inevitability creates a thermal pathway through an interface. Thermal interfaces can possess serious thermal resistances for heat conduction. The introduction of a thermal interface material (TIM) can drastically increase the thermal performance of the component. Exceptional thermal properties of multiwall carbon nanotubes (MWCNTs) have spurred interest in their use as TIMs. MWCNTs inherently grow in vertically-oriented, …

Transitional Flow Prediction Of A Compressor Airfoil, Vivek Hariharan

University of Kentucky Master's Theses

The steady flow aerodynamics of a cascade of compressor airfoils is computed using a two-dimensional thin layer Navier-Stokes flow solver. The Dhawan and Narasimha transition model and Mayle‟s transition length model were implemented in this flow solver so that transition from laminar to turbulent flow could be included in the computations. A method to speed up the convergence of the fully turbulent calculations has been introduced. In addition, the effect of turbulence production formulations and including streamline curvature correction in the Spalart-Allmaras turbulence model on the transition calculations is studied. These transitional calculations are correlated with the low and high …

Test 1982: New Holland Ts6030, Nebraska Tractor Test Lab

Nebraska Tractor Tests

ABOUT THE TEST REPORT AND USE OF THE DATA The test data contained in this report are a tabulation of the results of a series of tests. Due to the restricted format of these pages, only a limited amount of data and not all of the tractor specifications are included. The full OECD report contains usually about 30 pages of data and specifications. The test data were obtained for each tractor under similar conditions and therefore, provide a means of comparison of performance based on a limited set of reported data. EXPLANATION OF THE TEST PROCEDURES Purpose The purpose of …

Effect Of Free-Edges On Melt Pool Geometry And Solidification Microstructure In Beam-Based Fabrication Methods, Joy Elizabeth Davis

Browse all Theses and Dissertations

Laser and electron beam-based additive manufacturing of Ti-6Al-4V are under consideration for application to aerospace components. A critical concern for these processes is the ability to obtain a consistent and desirable microstructure and corresponding mechanical properties of the deposit. Based on the Rosenthal solution for a moving point-heat source, recent work has developed simulation-based process maps for the thermal conditions controlling microstructure (grain size and morphology) in beam-based deposition of semi-infinite geometries, where a steady-state melt pool exists away from free-edges. In the current study, the Rosenthal solution is modified to include the effects of free-edges. This is accomplished by …

Experimental Studies Of Turbulent Boundary Layers Over A Rough Forward-Facing Step And Its Coarse Scale Resolution Approximations, Huiying Ren

Browse all Theses and Dissertations

High spatial resolution PIV experiments are performed in the x-y plane at two different spanwise positions to compare the turbulent boundary layers over smooth and rough forward-facing-steps as well as the rough step's two coarse scale-resolution approximations. The Reynolds number based on the step's mean height, Re_h, is 3450 and the ratio of the boundary layer thickness to the step's height is δ/h = 8. The roughness topography on the top surface of the rough step is replicated from a realistic turbine blade and is intrinsically three-dimensional and highly irregular. The surface topographies of the coarse scale-resolution …

Heat Transfer Augmentation In A Narrow Rectangular Duct With Dimples Applied To A Single Wall, Carson Slabaugh

Electronic Theses and Dissertations

Establishing a clean and renewable energy supply is the preeminent engineering challenge of our time. Turbines, in some form, are responsible for more than 98 percent of all electricity generated in the United State and 100 percent of commercial and military air transport. The operation of these engines is clearly responsible for significant consumption of hydrocarbon fuels and, in turn, emission of green house gases into the atmosphere. With such wide-scale implementation, it is understood that even the smallest increase in the operating efficiency of these machines can lead to enormous improvements over the current energy situation. These effects can …

Study Of Microstructure Effect On The Thermal Properties Of Yttria-Stabilized-Zirconia Thermal Barrier Coatings Made By Atmospheric Plasma Spray And Pressing Machine, Monica Bohorquez De Silva

LSU Doctoral Dissertations

Thermal barrier coatings (TBCs) are used in gas turbine engines to achieve a higher working temperature and thus lead to better efficiency. Yttria-Stabilized-Zirconia (YSZ), a material with low thermal conductivity, is commonly used as the top coat layer to provide the thermal barrier effect. In this dissertation the thermo-physical properties of a variety of TBCs samples made out of different fabrication techniques were investigated and compared. The first set of samples was fabricated using a pressing machine device to fabricate 0.5 inch diameter disk shaped YSZ-Al2O3 samples. The YSZ-Al2O3 powder mixture was made of 0, 1, 2, 3, 4 and …

Feasibility Study Of Solar Driven Underground Cooling System, Michel E. Shafik

Durham School of Architectural Engineering and Construction: Dissertations, Theses, and Student Research

In the United States the peak electrical use occurs during the summer. In addition, the building sector consumes a major portion of the annual electrical energy consumption. One of the main energy consuming components in the building sector is the Heating, Ventilation, and Air-Conditioning (HVAC) systems. This research studies the feasibility of implementing a solar driven underground cooling system that could contribute to reducing building cooling loads. The developed system consists of an Earth-to-Air Heat Exchanger (EAHE) coupled with a solar chimney that provides a natural cool draft to the test facility building at the Solar Energy Research Test Facility …

Sensitivity Analysis Of The Johnson-Cook Plasticity Model For Hypervelocity Impacts: A Hydro-Code Study, Carlos David Castellanos

Open Access Theses & Dissertations

Computer simulations have been in use for decades in the modeling of hypervelocity impacts and general large deformation problems. Several computer codes have been developed to simulate this type of problems under a variety of geometric configurations and for any number of materials. These codes make use of several constitutive material models to simulate the response of the material under a variety of thermo-mechanical conditions. The Johnson-Cook constitutive model is widely used in the simulation hypervelocity impacts for the simulation of crater formation and even perforation of target structures. This thesis presents the results of a sensitivity study of this …

Multidisciplinary Collaborative Model For Complex, Angel Ernesto Delgado

Open Access Theses & Dissertations

Nowadays, most devices with advanced technology require the development of embedded systems with mechanical and electrical components as well as software including more than one discipline. These are devices that are usually complex in terms of composition and functionality and that design must follow a methodology in order to successfully design and launch a device of this nature. Hence, the assembly of a multidisciplinary engineering group is required to carry out such complex devices and develop a fully functional product. The group may also need an expert on the field that can provide guidance and knowledge where needed. This is …

Automated Fluid Handling And Leveling System For Multiple Material Stereolithography, Yinko I. Grajeda

Open Access Theses & Dissertations

This work addresses the development of an automated multiple material fluid handling and leveling system for its implementation into a Multiple-Material Stereolithography (MMSL) apparatus. A patent filed by Wicker et al. (US Patent 7,556,490) disclosing a MMSL apparatus served as the basis for the development of this work. The system is designed to operate in a variety of MMSL apparatus configurations. Fluid vats are designed to meet the enclosure constraints, facilitate the interface to the pump and sensor, and support the handling of the fluids. Due to its fluid isolation and bi-directional flow capabilities, a digital drive peristaltic pump is …

Processing Of Zrb2-Zrc-Zrxsiy Ceramic By Reactive Metal Penetration, Nischel B. Maheswaraiah

Open Access Theses & Dissertations

The processing of ZrB2-ZrC-ZrxSiy composite by reactive metal penetration was investigated as a successor to the ZrB2-SiC composites for hypersonic vehicles application, which cannot be used for extended time at temperatures greater than 1600C due to formation of SiO and CO gases. Zirconium (Zr), zirconium disilicide (ZrSi2), and boron carbide (B4C) were reacted in graphite crucibles for 60, 120, 180, and 240 minutes. Microscopy and x-ray diffraction (XRD) deduced the formation of a heterogeneous microstructure of ZrB2-ZrC-ZrxSiy precipitates surrounded by a solidified Zr-Si melt. Unreacted boron carbide was observed in samples held at 1860C for 60 minutes and 120 minutes, …

Development Of A Micro-Catbed For Miniature Thrusters, Chance Paul Garcia

Open Access Theses & Dissertations

The goal of this work is to develop a micro catalytic bed for miniature thrusters. A test bed was constructed for experimental testing to characterize several parts of the micro catalytic bed. The reactant fluid studied is 90% Hydrogen Peroxide (H2O2) by weight. Three different cross sectional area designs were tested to determine decomposition efficiency, temperature reaction propensity, optimum flow rate, and temperature distribution across each bed. The products of decomposition were condensed to measure the oxygen released from decomposition. The results will be used to develop the basis for a micro catalytic bed design to implement into future miniature …

The Research Of New Approaches To Coupling Windage Problem Based On Pressure Experiments And Analysis, Tao Jiang

Early Career Technical Journal (ECTJ)

Proceedings of the ASME Early Career Technical Conference, October 1-2, 2010. Woodruff School of Mechanical Engineering, Georgia Institute of Technology, Atlanta, Georgia

pp. 9-18

Collapse Analysis Of Tubes Under Quasi-Static Axial Loading, Anurag Dixit, Raghawendra P S Sisodia, Nitin K. Waghmare

Early Career Technical Journal (ECTJ)

Proceedings of the ASME Early Career Technical Conference, October 1-2, 2010. Woodruff School of Mechanical Engineering, Georgia Institute of Technology, Atlanta, Georgia

pp. 57-65