Mechanical Engineering Commons^™

Evaluation Of Turbulence Variable Distributions For Incompressible Fully Rough Pipe Flows, Emilie B. Fowler

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

The specific turbulent kinetic energy, root-mean-square fluctuating vorticity, and mean-vortexwavelength distributions are presented for fully rough pipe flow. The distributions of these turbulence variables are obtained from a proposed turbulence model. Many of the turbulence models commonly used for computational fluid dynamics are based on an analogy between molecular and turbulent transport. However, traditional k-ε and k-ω models fail to exhibit proper dependence on the molecular viscosity. Based on a rigorous application of the Boussinesq’s hypothesis, Phillips proposed a vorticity-based transport equation for the turbulent kinetic energy. The foundation for this vorticity-based transport equation is presented. In future development of …

Enhanced Tribological Properties Of Surfaces Patterned With Dlc/Su8 Microstructures, Luke Osborn

Mechanical Engineering Undergraduate Honors Theses

Textured surfaces can reduce friction due to decreased contact area between two surfaces, and could therefore increase the reliability of micro-electro-mechanical systems (MEMS). The problem with some microtextures is their inability to withstand significant amounts of wear, often deforming or breaking, thus limiting their potential uses and overall effectiveness. In this study, connected and isolated SU8 microstructures with and without diamond-like coating (DLC) were designed to investigate the effects of these microstructures on the tribological performance of a surface. Friction studies were conducted using a tribometer, while surface topography and wear were characterized by scanning electron microscopy (SEM), optical microscope, …

Design And Use Of An Alternative Fuel Testing Apparatus And Assessment Of The Feasibility Of Biodiesel, Matthew Tanner

Master’s Theses

Petroleum supply and environmental pollution issues constantly increase interest in renewable low polluting alternative fuels. Published test results show decreased pollution with similar power output and fuel consumption from Internal Combustion Engines (ICE) burning alternative fuels. More specifically, diesel engines burning biodiesel derived from plant oils and animal fats not only reduce harmful exhaust emissions but are renewable and environmentally friendly. To validate these claims and assess the feasibility of alternative fuels, independent engine dynamometer and emissions testing was performed. A testing apparatus capable of making relevant measurements was designed, built, and used to test and determine the feasibility of …

Assessing The Engineering Performance Of Affordable Net-Zero Energy Housing, Jordan P. Wallpe

Purdue Polytechnic Masters Theses

The purpose of this research was to evaluate affordable technologies that are capable of providing attractive, cost-effective energy savings to the housing industry. The research did so by investigating the 2011 Solar Decathlon competition, with additional insight from the Purdue INhome. Insight from the Purdue INhome verified the importance of using a three step design process to design a net-zero energy building. In addition, energy consumption values of the INhome were used to compare and contrast different systems used in other houses.

Evaluation of unbiased competition contests gave a better understanding of how a house can realistically reach net-zero. Upon …

Implementation Of Wireless Temperature Sensors For Continuous Condition Monitoring Of Railroad Bearings, Andoni Zagouris Ii

Theses and Dissertations - UTB/UTPA

At present there are no existing bearing health monitoring systems capable of continuous monitoring of railroad bearings. Current wayside equipment is used to collect intermittent bearing temperatures, which at times could be every 65 km (~40 mi). To answer this need, IONX, LLC, a subsidiary of Amsted Rail, Inc., has developed low power Wireless Sensor Nodes (WSNs) which can be retrofitted to existing bearing adapters. The WSNs provide continuous monitoring of bearing temperatures as well as the current ambient temperature. Since the nodes are affixed to the bearing adapter surface, a correlation is necessary to estimate the bearing cup temperature …

Investigation Of Relative Importance Of Some Error Sources In Particle Image Velocimetry, Jeff R. Harris

All Graduate Plan B and other Reports, Spring 1920 to Spring 2023

Particle image velocimetry (PIV) is an optical technique used to measure fluid velocity. PIV measurements have many sources that create uncertainty in the velocity results. The objective of this report is to investigate some commonly cited uncertainty sources and to show methods than can be used to find the value of the uncertainty sources. These sources are: magnification, calibration, perspective, resolution and the computation scheme. Experiments were conducted to find the impact that sources have on the velocity measurements. Several methods are presented to demonstrate how to measure the uncertainty of error for a PIV experiment. Some error quantities are …

Computational Representation And Reasoning Support For Requirements Change Management In Complex System Design, Beshoy Morkos

All Dissertations

Requirements play a critical role within any design process and the activity of identifying and maintaining a system's requirements is essential to. However, design is a complex and iterative process, where requirements are continuously evolving and are volatile. This change, if not managed, may result in undesired uncertainty within the design process leading to monetary losses and time delays, as the changing of requirements has been recognized as a major cause of project failure. In order to mitigate issues that arise due to requirement change propagation, this research presents a computational reasoning tool to help designers and engineers predict change …

Clustering And Classification Of Multivariate Stochastic Time Series In The Time And Frequency Domains, Ryan Schkoda

All Dissertations

The dissertation primarily investigates the characterization and discrimination of stochastic time series with an application to pattern recognition and fault detection. These techniques supplement traditional methodologies that make overly restrictive assumptions about the nature of a signal by accommodating stochastic behavior. The assumption that the signal under investigation is either deterministic or a deterministic signal polluted with white noise excludes an entire class of signals -- stochastic time series. The research is concerned with this class of signals almost exclusively. The investigation considers signals in both the time and the frequency domains and makes use of both model-based and model-free …

Applying Chaotic Advection To Rheology: An In Situ Structuring Rheometer, Ramaswami Subrahmanian

All Dissertations

A prototype In Situ Structuring Rheometer (ISSR) was designed and implemented to study changes in shear viscosity of polymer blends and composites while processing them in such a way as to control the evolution of microstructure. The ISSR is based on a regime of fluid mechanics known as chaotic advection, in which simple time-periodic flow fields can cause fluid particles to move chaotically. Chaotic advection is also the basis of Smart Blending, a technology employed to process polymer blends having a variety of morphologies at a fixed composition, and polymer composites in which the additives have been arranged into layered …

Buffering Pv Output During Cloud Transients With Energy Storage, Yacouba Moumouni

UNLV Theses, Dissertations, Professional Papers, and Capstones

Consideration of the use of the major types of energy storage is attempted in this thesis in order to mitigate the effects of power output transients associated with grid-tied CPV systems due to fast-moving cloud coverage. The approach presented here is to buffer intermittency of CPV output power with an energy storage device (used batteries) purchased cheaply from EV owners or battery leasers. When the CPV is connected to the grid with the proper energy storage, the main goal is to smooth out the intermittent solar power and fluctuant load of the grid with a convenient control strategy. This thesis …

Perceptions Measurement Of Professional Certifications To Augment Buffalo State College Baccalaureate Technology Programs, As A Representative American Postsecondary Educational Institution, Christopher N. Brown

Industrial Technology Theses

The purpose of this study was to assess, measure, and analyze whether voluntary, nationally-recognized professional certification credentials were important to augment technology programs at Buffalo State College (BSC), as a representative postsecondary baccalaureate degree-granting institution offering technology curricula. Six BSC undergraduate technology programs were evaluated within the scope of this study: 1.) Computer Information Systems; 2.) Electrical Engineering, Electronics; 3.) Electrical Engineering, Smart Grid; 4.) Industrial Technology; 5.) Mechanical Engineering; and 6.) Technology Education. This study considered the following three aspects of the problem: a.) postsecondary technology program enrollment and graduation trends; b.) the value/awareness of professional certifications to employers …

A Validation And Comparison About Vabs-Ide And Vabs-Gui, Teng Hu

All Graduate Plan B and other Reports, Spring 1920 to Spring 2023

Variational Asymptotic Beam Section (VABS) analysis is a computer code for design and analysis of slender structure such as rotor blades, wind turbine blades, missiles, and rockets more efficiently than a full three-dimensional finite element analysis. VABS enables a rigorously a dimensional reduction of the original three-dimensional nonlinear analysis into a one-dimensional nonlinear beam analysis and a two-dimensional linear cross-sectional analysis. The VABS code has been extensively used in academia and industry for comput- ing the sectional properties and recovering three-dimensional fields of composite slender structures. Recently two graphic user interface, namely VABS-IDE and VABS-GUI, have been developed to automatic …

Effect Of Orifice Shape On Synthetic Jet Efficiency, David J. Nani

All Graduate Plan B and other Reports, Spring 1920 to Spring 2023

A synthetic jet is formed by periodic oscillation of a fluid through an orifice. The oscillatory motion is driven by diaphragm or other driver. Previous studies have demonstrated that synthetic jet formation and time-averaged cavity pressure are a function of the orifice shape. Traditionally, the performance of the jet is evaluated with varying configurations of fixed driver input voltage or fixed driver displacement. Neither of these measures accurately reflect the efficiency of the actuator. Defining efficiency as "desired output divided by required input," these traditional measures may not account for increase in required driving current or force.

A sharp inside …

Streambed Thermal Property Instrument (Spi), James Alwel Dayie

All Graduate Plan B and other Reports, Spring 1920 to Spring 2023

The purpose of this research, the Streambed thermal Property Instrument (SPI) is to determine the applicability of this instrument for in situ thermal (conductivity and diffusivity) and porous flow (magnitude and direction) measurements. Currently, no such thermal instrument exists for such in situ measurements and the reason for developing this unique instrument, the SPI to fill the technology gap in sediment thermal property measurement devices. Prior to testing the instrument under controlled laboratory conditions to determine its functionality through a series of static and flow tests, the instrument was designed and built. A lab-sized version of an actual river called …

In Situ Method Of Measuring Atmosphere Neutral Winds With A Rigid Falling Sphere, Joshua F. Martineau

All Graduate Plan B and other Reports, Spring 1920 to Spring 2023

The new falling sphere instruments will measure lower E-region winds and density, which are critical for many of the electrodynamics and plasma physics studies that are carried out as part of the NASA suborbital rocket program. The new falling sphere design will take advantage of modern commercially available electronic components and materials. Of primary importance, it is proposed to fly an in-situ instrument that targets the measurement of neutral wind profiles over the altitude range from 80 to 150 km, with accuracy better than that achieved in previous implementations of the falling sphere technique and those typically obtained with the …

Material Handling System For Robotic Natural Orifice Surgery, Jeff Midday

Department of Mechanical and Materials Engineering: Dissertations, Theses, and Student Research

Natural Orifice Translumenal Endoscopic Surgery (NOTES) is a relatively new surgical approach which uses no external incisions, thereby improving cosmetic outcomes, decreasing overall recovery time and reducing the risk of external infection. In standard NOTES, flexible endoscopic tools have been used to carry out a variety of surgical procedures in the abdomen. As an alternative, miniature in vivo robots can be fully inserted into the peritoneal cavity and utilized to perform various surgical procedures. These in vivo robots eliminate tool triangulation issues, improve multi-tasking capabilities and greatly increase freedom and dexterity when compared to standard endoscopic and laparoscopic tools. One …

Improving Health Care Quality And Safety: The Development And Assessment Of Laparoscopic Surgery Instrumentation, Practices And Procedures, Bernadette Mccrory

Department of Mechanical and Materials Engineering: Dissertations, Theses, and Student Research

Adverse events due to medical errors are a leading cause of death in the United States exceeding the mortality rates of motor vehicle accidents, breast cancer and AIDS. Improvements can and should be made to reduce the rates of preventable surgical errors since they account for nearly half of all adverse events within hospitals. Although minimally invasive surgery has proven patient benefits such as reduced postoperative pain and hospital stay, its operative environment imposes substantial physical and cognitive strain on the surgeon increasing the risk of error. In order to mitigate errors and protect patients, a multidisciplinary approach was taken …

Phase Resolved Near-Field Mode Imaging For The Design Of Frequency-Selective Surfaces, Edward C. Kinzel, J. C. Ginn, R. L. Olmon, D. J. Shelton, B. A. Lail, I. Brenner, M. B. Sinclair, M. B. Raschke, G. D. Boreman

Mechanical and Aerospace Engineering Faculty Research & Creative Works

No abstract provided.

Shock And Vibration Isolation System For Ambulatory And Litter Patients In Ground And Air Medical Transport, Mohamad R. Hachem

UNLV Theses, Dissertations, Professional Papers, and Capstones

This project explored the effectiveness of seat and litter air bladder technologies in reducing patient exposure to whole body shock and vibration during ground borne and airborne medical transport. Several seat and litter air bladder configurations were examined during field tests in a U.S. Army RG-33 MRAP ambulance and a U.S. Army HH-60M Black Hawk helicopter. The MRAP field tests were conducted at Ft. Detrick, Maryland. The Black Hawk field tests were conducted at Ft. Rucker, Alabama.

During the field tests, tri-axial vibration signals were recorded on a 16-channel CoCo90 Data Logger/Frequency Analyzer and then post processed in the laboratory …

A Refreshable And Portable E-Braille System For The Blind And Visually Impaired, Mohammad Yousef Saadeh

UNLV Theses, Dissertations, Professional Papers, and Capstones

The objective of this research is to design an affordable Braille tactile display that is wearable, refreshable, and portable. The device is intended to be used as an output device that can playback stored media. It can be also incorporated with current Braille reading technologies. The device will control both the electrical and mechanical stimulations to optimize the sensation and ensure extended use of the device. This work is concerned mainly with the mechanical aspects of the design.

This research proposed the development of a finger-wearable, scanning-style electric stimulation based (electrotactile) Braille display with sensing and adaptive rendering/actuation functions for …

Using Stereo Particle Image Velocimetry To Quantify And Optimize Mixing In An Algae Raceway Using Delta Wings, Blake W. Lance

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Biofuel research has been continually growing over the past six decades. Of the potential sources for biofuels, microalgae is the most promising, and circulating (raceway) ponds are the most cost-effective method for growing microalgae in abundance. Nevertheless, biofuel production from algae must be more efficient to be competitive with traditional fuels. Previous studies using several airfoils, triangles, and squares at high angles to the flow direction (angle of attack) show an increase in mixing in raceways and can improve productivity by up to a factor of 2.2. Researchers show that increasing growth by increasing mixing is a repeatable effect that …

Simulation Of Counterintuitive Pressure Drop In A Parallel Flow Design For A Specimen Basket For Use In The Advanced Test Reactor, Adam X. Zabriskie

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

To continue improving nuclear energy, new materials must be tested in testing reactors such as the Advanced Test Reactor (ATR) at Idaho National Laboratory. A new test cap section allowed coolant to contact specimens tested in the ATR. A parallel channel test cap section should reduce the pressure drop across this section compared to a single channel. A fluid experiment conducted by Idaho State University showed the pressure drop was actually greater. A Computation Fluid Dynamics simulation using STAR-CCM+ was conducted of the fluid experiment to explain the abnormal pressure drop. The simulation provided evidence of ow through the test …

Autocorrelation-Based Estimate Of Particle Image Density In Particle Image Velocimetry, Scott O. Warner

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

In Particle Image Velocimetry (PIV), the number of particle images per interrogation region, or particle image density, impacts the strength of the correlation and, as a result, the number of valid vectors and the measurement uncertainty. Therefore, any a-priori estimate of the accuracy and uncertainty of PIV requires knowledge of the particle image density. An autocorrelation-based method for estimating the local, instantaneous, particle image density is presented. Synthetic images were used to develop an empirical relationship based on how the autocorrelation peak magnitude varies with particle image density, particle image diameter, illumination intensity, interrogation region size, and background noise.

This …

Effective Thermal Conductivity Of Tri-Isotropic (Triso) Fuel Compacts, Charles P. Folsom

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

The Next Generation Nuclear Plant (NGNP) program objective is to develop a new type of nuclear reactor that produces process heat instead of electricity. The process heat can be used in the production of hydrogen and many other industrial processes. As part of the NGNP program a new type of nuclear fuel is being developed. The fuel is a composite construction of specially coated fuel particles and graphite pressed together in a cylindrical compact.

Thermal conductivity is an important thermophysical property of the fuel that needs to be measured. Knowledge of the thermal conductivity of the fuel will provide accurate …

Heater Geometry And Heat Flux Effects On Subcooled, Thin Wire, Nucleate Pool Boiling In Microgravity, Troy Munro

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

The purpose of this thesis is to study the effects of microgravity, surface geometry, and heat dissipation per unit area (heat flux) on boiling heat transfer. Boiling is able to move a significant amount of heat for a small area in comparison to other heat transfer methods. Space systems could benefit from the development of thermal management systems that use boiling heat transfer because they would be smaller, more robust, and less expensive. However, boiling is an extremely complicated process which has no comprehensive models to predict its behavior. Multiple correlations have been developed which relate heat transfer efficiencies to …

Bubble Coalescence And Breakup Modeling For Computing Mass Transfer Coefficient, Ryan A. Mawson

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Modeling fluid behavior with computer numerical models can be very difficult due to the physical phenomenon which can be present in complex fluid systems. One difficult situation to model is when there is more than one type of fluid in a system. Some of these systems include fluids which do not mix, such as is the case when a liquid and a gas are present. In this situation, the gas phase will form bubbles which are dispersed throughout the liquid phase. Modeling the breakup and coalescence of these bubbles is critical to correctly model this type of situation.

There exist …

The Engineering Process For The Design Of A Motorcycle Chassis And Suspension, Derek J. Noce

Doctoral Dissertations and Master's Theses

The thesis objective is to define and establish an engineering process for the design of a modern motorcycle chassis and suspension. The engineering process focuses on the interdisciplinary fields of engineering dealing with design and structural optimization. Specialized software, such as Motorcycle Kinematics, MATLAB, CATIA, HEEDS Professional, and NASTRAN are utilized. Motorcycle Kinematics is used to set up the preliminary motorcycle geometry, and MATLAB is a used to analyze the kinematics and stability of the motorcycle based on this geometry. CATIA (Computer Aided Three-Dimensional Interactive Application) is used to graphically illustrate the geometry of the motorcycle in three dimensional space. …

Development And Testing Of An Actively Adjustable Stiffness Mechanism, Eleazar Marquez, Robert Freeman, Horacio Vasquez

Mechanical Engineering Faculty Publications

This study presents the comparison of the theoretical and experimental results of the performance of an adjustable stiffness mechanism. In particular, the use of redundant actuation is emphasized in the design of a one degree-of-freedom Watt II mechanism capable of independently controlling the effective stiffness without a change in equilibrium position. This approach is in contrast to spring mechanism designs unable to actively control the spring rate independent of deflection, and with potential applications in various types of suspension and assembly systems. Results indicate that two direct drive brush-type direct current motors are required to drive the redundantly actuated mechanism …

Predictive Simulation Of Gait At Low Gravity Reveals Skipping As The Preferred Locomotion Strategy, Marko Ackermann, Antonie J. Van Den Bogert

Mechanical Engineering Faculty Publications

The investigation of gait strategies at low gravity environments gained momentum recently as manned missions to the Moon and to Mars are reconsidered. Although reports by astronauts of the Apollo missions indicate alternative gait strategies might be favored on the Moon, computational simulations and experimental investigations have been almost exclusively limited to the study of either walking or running, the locomotion modes preferred under Earth's gravity. In order to investigate the gait strategies likely to be favored at low gravity a series of predictive, computational simulations of gait are performed using a physiological model of the musculoskeletal system, without assuming …

The Application Of Origami To The Design Of Lamina Emergent Mechanisms (Lems) With Extensions To Collapsible, Compliant And Flat-Folding Mechanisms, Holly Greenberg

Theses and Dissertations

Lamina emergent mechanisms (LEMs) are a subset of compliant mechanisms which are fabricated from planar materials; use compliance, or flexibility of the material, to transfer energy; and have motion that emerges out of the fabrication plane. LEMs provide potential design advantages by reducing the number of parts, reducing cost, reducing weight, improving recyclability, increasing precision, and eliminating assembly, to name a few. However, there are inherent design and modeling challenges including complexities in large, non-linear deflections, singularities that exist when leaving the planar state, and the coupling of material properties and geometry in predicting mechanism behavior. This thesis examines the …