Mechanical Engineering Commons^™

Mathematical Description And Mechanistic Reasoning: A Pathway Toward Stem Integration, Paul J. Weinberg

Journal of Pre-College Engineering Education Research (J-PEER)

Because reasoning about mechanism is critical to disciplined inquiry in science, technology, engineering, and mathematics (STEM) domains, this study focuses on ways to support the development of this form of reasoning. This study attends to how mechanistic reasoning is constituted through mathematical description. This study draws upon Smith’s (2007) characterization of mathematical description of scientific phenomena as ‘‘bootstrapping,’’ where negotiating the relationship between target phenomena and represented relations is fundamental to learning. In addition, the development of mathematical representation presents a viable pathway towards STEM integration. In this study, participants responded to an assessment of mechanistic reasoning while cognitive interviews …

Study On The Dispersion Of Particles At A Fluid-Liquid Interface And Its Application In Hydrophilous Pollination, Naga Aditya Musunuri

Dissertations

This dissertation work describes the physics of particle adsorption and the spontaneous dispersion of powders that occurs when they come in contact with a fluid-liquid interface and its application in hydrophilous pollination of Ruppia Maritima, an aquatic plant. The dispersion of particles can occur so quickly that it appears explosive, especially for small particles on the surface of mobile liquids like water. PIV (Particle Image Velocimetry) measurements show that the adsorption of a spherical particle at the interface causes an axisymmetric streaming flow about the vertical line passing through the particle center. The fluid directly below the particle rises upward, …

Fast Estimation Model Of Pressure-Temperature Response For Planning Focused Ultrasound Surgery, Tariq Mohammad Arif

Dissertations

High Intensity Focused Ultrasound (HIFU) is becoming a widely accepted modality for extracorporeal non-invasive hyperthermia and surgical procedures. Since ultrasonic transducers need to operate in various challenging body locations, the arrangement of their array elements can be optimized to improve the capability of controlling focus intensity. In the first part of this dissertation, patterns of pressure field variations with several selected design variables (kerf, transducer element’s number and element’s width-height) are studied. These patterns indicate that there is a more suitable shape and arrangement of transducer elements in a specified area to achieve highest possible pressure. In order to obtain …

The Effects Of Coolant Pipe Geometry And Flow Conditions On Turbine Blade Film Cooling, Muhammad K. Akbar, Bashir Alsaidi, Roger Painter, Lonnie Sharpe, S. Mostafa Ghiaasiaan

Mechanical and Manufacturing Engineering Faculty Research

The performance of gas turbine engines can be improved by increasing the inlet gas temperature. Turbine blades can be damaged by high gas temperature, unless additional cooling mechanisms are incorporated to maintain the blades below an acceptable temperature limit. Film cooling techniques are often used to cool the blades to avoid damages. The performance of film cooling depends on several parameters, however. In this paper past research on film cooling is reviewed and areas in need of further investigation are identified. Computational fluid dynamics (CFD) simulations are then conducted on the widely-used single-hole film cooling arrangements in which coolant jets …

Energy From Chemical Reactions: Understanding The Combustion Engine, Tammy Guthrie, Kathy Prophet, Greg Herzig, Cassie Kautzer

Middle School Lesson Plans

Automobiles produce a large amount of heat generated by the burning of gasoline. Burning gasoline is a chemical reaction that causes a phase change. This is called combustible energy. During combustion fuel combines with oxygen to release energy (such as heat, light, sound) along with another product that is often considered waste. Most of the energy produced is not used to power the automobile, but is released as heat. 19.3 pounds of the greenhouse gas, carbon dioxide, is produced from the combustion of 1 gallon of U.S. gasoline according to the U.S. Energy Information Administration.

Solubility And Thermodynamic Modeling Of Carcinogenic Nitrosamines In Aqueous Amine Solvents For Co2 Capture, Jesse Thompson, Naser Matin, Kunlei Liu

Center for Applied Energy Research Faculty and Staff Publications

A better understanding of key fundamental properties of nitrosamines, including their solubility in aqueous amine solvents, is needed to understand and accurately model the vapor-phase emission levels from operating CO₂ capture systems. In this work, the first experimental Henry's volatility coefficient of a nitrosamine was obtained with a novel method using static headspace solid phase micro extraction (SPME) and gas chromatography mass spectrometry (GC/MS). The experimentally determined Henry's volatility coefficient of nitrosopyrrolidine (NPY) was found to be around 0.02 (dimensionless) at 25 °C, and falls in the range of a semi-volatile compound. A linear temperature dependency of the Henry's …

Techno-Economic Analysis Of A Secondary Air Stripper Process, J. R. Heberle, Heather Nikolic, Jesse Thompson, Kunlei Liu, Lora L. Pinkerton, David Brubaker, James C. Simpson, Song Wu, Abhoyjit S. Bhown

Center for Applied Energy Research Faculty and Staff Publications

We present results of an initial techno-economic assessment on a post-combustion CO₂ capture process developed by the Center for Applied Energy Research (CAER) at the University of Kentucky using Mitsubishi Hitachi Power Systems’ H3-1 aqueous amine solvent. The analysis is based on data collected at a 0.7 MWe pilot unit combined with laboratory data and process simulations. The process adds a secondary air stripper to a conventional solvent process, which increases the cyclic loading of the solvent in two ways. First, air strips additional CO₂ from the solvent downstream of the conventional steam-heated thermal stripper. This extra stripping …

Thermal Degradation Pathways Of Aqueous Diamine Co2 Capture Solvents, Jesse Thompson, Henry Richburg, Kunlei Liu

Center for Applied Energy Research Faculty and Staff Publications

Diamines have shown promise as CO₂ capture solvents, yet very little is known about their pathway for thermal degradation. In this study, diamine thermal degradation was quantitatively monitored in lab-scale experiments on four aqueous diamine solvents; ethylenediamine (EDA) 1,2-propanediamine (1,2-DAP), 1,3-diaminopropane (1,3-DAP) and N-methyl-1,2-ethanediamine (NMEDA), to gain a more comprehensive understanding of their degradation pathway(s). The major degradation products were identified by high resolution time-of-flight mass spectrometry (TOF-MS). Degradation pathways were proposed showing that the primary thermal degradation route for this class of amine are through carbamate formation followed by intermolecular cyclization to form an imidazolidinone or nucleophilic attack …

Solvent Degradation And Emissions From A 0.7mwe Pilot Co2 Capture System With Two-Stage Stripping, Jesse Thompson, Heather Nikolic, Megan Combs, Saloni Bhatnagar, Jonathan Pelgen, Keemia Abad, Kunlei Liu

Center for Applied Energy Research Faculty and Staff Publications

The UKy-CAER team successfully tested an advanced 0.7 MWe post-combustion CO₂ capture system on a coal-fired power plant using a heat integration process combined with two-stage stripping to enhance the CO₂ absorber performance. One of the unique feature of the UKy-CAER integrated process is a two-stage stripping unit for solvent regeneration. The secondary stripper is empowered by the heat rejection from a conventional steam-heated (primary) stripper. The secondary stripper outlet stream at the commercial scale can be used as boiler secondary combustion air, consequently enriching the flue gas with CO₂, resulting in less energy penalty required …

Effect Of Wall Cooling On Boundary-Layer-Induced Pressure Fluctuations At Mach 6, C. Zhang, Lian Duan, M. Choudhari

Mechanical and Aerospace Engineering Faculty Research & Creative Works

No abstract provided.

Kinetic Energy Investigation, Mike Jackson

High School Lesson Plans

Students will build a mouse trap powered car that converts elastic potential energy contained in the trap’s spring to linear kinetic energy of the car. The release of this energy results in a net force which leads to linear acceleration. This acceleration can be measured with Vernier Logger Pro®, and using Newton’s Second Law of Motion, the net force can be calculated. Finally, using the concept of work, the final kinetic energy of the car can be calculated. Once students become familiar with the calculation of work and energy, the teacher will challenge the students to modify their cars to …

A Parametric Investigation And Optimization Of A Cylindrical Explosive Charge, Logan Ellsworth Beaver

Master's Theses (2009 -)

Explosive device design has a wide impact in the space, manufacturing, military, and mining industries. As a step toward computer assisted design of explosives, an optimization framework was developed using the Design Analysis Kit for Optimization and Terrascale Applications (Dakota). This software was coupled with the hydrocode CTH. This framework was applied to three exploding cylinder models, two in 1D and one in 2D. Gradient descent, dividing rectangles, and a genetic algorithm were each applied to the one-dimensional models. Parametric studies were performed as a basis for comparison with the optimization algorithms, as well as qualifying the 1D model's accuracy. …

X-Ray Tube Anode Balance Analysis And Vacuum Balancer Parameter Optimization, Matthew Malak

Master's Theses (2009 -)

A manufacturing facility is introducing the company's first straddle mount liquid metal spiral groove bearing (SGB) on a rotating anode x-ray tube. In a manufacturing environment, it is critical that processes are robust and timely to drive down costs while also responding to market demand for improvement. There is currently a lot of variation in the anode balance process. Furthermore, there are repeatability questions surrounding the new balancing system that is used in this anode balance process. To better understand the characteristics of the new liquid metal SGB anode and the effects of measurement system variation, the measurement system will …

Adaptive Control Of Joystick Steering In Recreational Boats, John Bayless

Master's Theses (2009 -)

This thesis addresses the challenge of commissioning recreational boats with joystick control when the boat’s physical parameters are not known. The research was conducted by following a model-based, systems engineering approach which leveraged MATLAB simulations and scale-model physical testing. The outcome of the research is a working methodology using L1 Adaptive Control which provides fast adaption in a way that could reduce the cost of commissioning recreational boats with joystick control, improve the robustness of the final design, and potentially expand the accessible market to new boat types.

Investigation Of Lattice Structures And Analysis Of Strut Geometry., Zachary D Denzik

Electronic Theses and Dissertations

This study involves the evaluation of lattice specimens fabricated using additive manufacturing as well as investigation of the influence of unit cell connection geometry. Lattice topologies of face-centered cells and body-centered cells were modeled, investigated using finite element analysis (FEA) for each specimen, manufactured using direct metal laser sintering (DMLS) with maraging steel powder, and mechanically tested. The strut diameter of each topology was altered to yield four different mass reductions from a solid cube, ranging from 55%-90% mass reduction. Three iterations of 1000mm³ lattice specimens were investigated. The first iteration consisted 0.5mm plates on the top and bottom …

Determining H2O Vapor Temperature And Concentration In Particle-Free And Particle-Laden Combustion Flows Using Spectral Line Emission Measurements, John Robert Tobiasson

Theses and Dissertations

There is a growing need for the clean generation of electricity in the world, and increased efficiency is one way to achieve cleaner generation. Increased efficiency may be achieved through an improved understanding of the heat flux of participating media in combustion environments. Real-time in-situ optical measurements of gas temperature and concentrations in combustion environments is needed. Optical methods do not disturb the flow characteristics and are not subject to the temperature limitation of current methods. Simpler, less-costly optical measurements than current methods would increase the ability to apply them in more circumstances. This work explores the ability to simultaneously …

Improving Crash Safety Of Jet Dragsters Through Modeling And Analysis, Paige Leigh Sanchez

Theses and Dissertations

The objective of this thesis was to analyze how additional foam implementation in a jet dragster driver’s compartment can improve driver safety in the case of an accident. This analysis was divided into two sections: a crash simulation analysis and a base excitation mass-spring-damper model analyzing foam behavior. The jet dragster crash simulation modeled, reflected a Larsen Motorsports jet dragster accident in 2011, where a dragster hit the wall at 270 mph between a 43 to 60 degree angle. A static structural simulation, using the dragster chassis, was modeled in ANSYS and several dynamic simulations at varying impact angles were …

Tuning Micro-Electro-Mechanical Resonators For Maximum Dynamic Range, Joseph William Fisher

Theses and Dissertations

This research seeks to improve the linear dynamic range (LDR) of micro-electromechanical systems (MEMS) resonators, which are commonly used in sensing and timing applications. We address specifically the need for devices whose response is relatively large yet remains single-valued near resonance. We develop and analyze a model for a class of electrostatically actuated micro structures that includes higher order electrostatic effects, thereby allowing one to determine the LDR for devices that are tuned to eliminate cubic order nonlinear effects. The inclusion of the capacitive forces produces a model that is best solved by expanding the force in a Taylor series. …

Cal Poly Table Top, Kelsey M. Ishimatsu Jacobson, Andrew J. Whitney

Mechanical Engineering

Since many tables currently used at Cal Poly are not ideal for active design situations, we have designed, built and tested to be used in design classrooms with an emphasis on using the tables to quickly prototype ideas. This table is a standing height table in a trapezoidal shape which can comfortably seat four people. The modular design of the table allows multiple tables to be use to create different shapes so that the tables can be used in multiple ways.

Application Of Dfx Methods To A Gait Rehabilitation System, Devin K. Elley

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

Walking is an important physical activity that offers major health benefits for those who are able to perform the task. However, there are millions of people worldwide who have lost the ability to walk from physical accidents or a disease which limits the ability for them to use their legs. Often these patients use gait therapy to learn how to walk again. During this gait therapy, a physical therapist may use gait rehabilitation machines to assist the patient in learning to walk in a correct gait path.

Two gait rehabilitation machine iterations were designed to produce an effective rehabilitation machine …

Development Of The Compact Jet Engine Simulator From Concept To Useful Test Rig, Henry H. Haskin

Mechanical & Aerospace Engineering Theses & Dissertations

NASA had a goal to develop a set of modeling tools for designing next generation civil transport aircraft with reduced noise, emissions and increased fuel efficiency by 2016. To verify the models, a database of aerodynamic and acoustic data was needed for an unconventional flying wing design that was predicted to meet the goals. A Compact Jet Engine Simulator (CJES) was needed as the jet source for the 5.8% scale model. Ultra-Compact Combustor Technology from the Air Force Research Laboratory was used to reduce the conventional burner acoustic test rigs down to the required scale size. The Air Force design …

Initiating Event Analysis Of A Lithium Fluoride Thorium Reactor, Nicholas Charles Geraci

Engineering Management & Systems Engineering Theses & Dissertations

The primary purpose of this study is to perform an Initiating Event Analysis for a Lithium Fluoride Thorium Reactor (LFTR) as the first step of a Probabilistic Safety Assessment (PSA). The major objective of the research is to compile a list of key initiating events capable of resulting in failure of safety systems and release of radioactive material from the LFTR.

Due to the complex interactions between engineering design, component reliability and human reliability, probabilistic safety assessments are most useful when the scope is limited to a single reactor plant. Thus, this thesis will study the LFTR design proposed by …

The Effect Of Bone And Ligament Morphology Of Ankle Joint Loading In The Neutral Position, Jinhyuk Kim

Mechanical & Aerospace Engineering Theses & Dissertations

Computational modeling of joints is used to investigate the effect of injuries, to plan surgeries, and to answer questions about joints that cannot be answered experimentally. Existing models of the ankle joint are moving toward being able to model specific patients, however, they do not include all of the anatomy (e.g., bones and/or ligaments) and have restrictive boundary conditions. These simplification in anatomy are made to minimize pre-processing and computation time. Because biomechanical modeling is increasingly focused on the implementation of patient specific cases, the effects of including more anatomical structures and determining how they affect the model results is …

Investigation, Modeling And Validation Of Digital Bridge For A New Generation Hot-Wire Anemometer, Karthik Kamalakar Joshi

Mechanical & Aerospace Engineering Theses & Dissertations

The Digital Bridge Thermal Anemometer (DBTA) is a new generation anemometer that uses advanced electronics and a modified half-Wheatstone bridge configuration, specifically a sensor and a shunt resistor in series. This allows the miniaturization of the anemometer and the communication between host computer and anemometer is carried out using serial or ethernet which eliminates the noise due to the use of long cables in conventional anemometer and the digital data sent to host computer is immune to electrical noise. In the new configuration the potential drop across a shunt resistor is used to control the bridge.

This thesis is confined …

A Low Cost Inflatable Cubesat Drag Brake Utilizing Sublimation, Adam Charles Horn

Mechanical & Aerospace Engineering Theses & Dissertations

The United Nations Inter-Agency Debris Coordination Committee has adopted a 25-year post-mission lifetime requirement for any satellite orbiting below 2000 km in order to mitigate the growing orbital debris threat. Low-cost CubeSats have become important satellite platforms with startling capabilities, but this guideline restricts them to altitudes below 600 km because they remain in orbit too long. In order to enable CubeSat deployments at higher release altitudes, a low-cost, ultra-reliable deorbit device is needed.

This thesis reports on efforts to develop a deployable and passively inflatable drag brake that can deorbit from higher orbital altitudes, thereby complying with the 25-year …

Stair Negotiation Made Easier Using Novel Interactive Energy-Recycling Assistive Stairs, Yun Seong Song, Sehoon Ha, Hsiang Hsu, Lena H. Ting, C. Karen Liu

Mechanical and Aerospace Engineering Faculty Research & Creative Works

Here we show that novel, energy-recycling stairs reduce the amount of work required for humans to both ascend and descend stairs. Our low-power, interactive, and modular steps can be placed on existing staircases, storing energy during stair descent and returning that energy to the user during stair ascent. Energy is recycled through event-triggered latching and unlatching of passive springs without the use of powered actuators. When ascending the energy-recycling stairs, naive users generated 17.4 ± 6.9% less positive work with their leading legs compared to conventional stairs, with the knee joint positive work reduced by 37.7 ± 10.5%. Users also …

Design And Analysis Of Adaptive Control Systems Over Wireless Networks, Ali Albattat, Benjamin Gruenwald, Tansel Yucelen

Mechanical and Aerospace Engineering Faculty Research & Creative Works

In this paper, we study the design and analysis of adaptive control systems over wireless networks using event-triggering control theory. The proposed event-triggered adaptive control methodology schedules the data exchange dependent upon errors exceeding user-defined thresholds to reduce wireless network utilization and guarantees system stability and command following performance in the presence of system uncertainties. Specifically, we analyze stability and boundedness of the overall closed-loop dynamical system, characterize the effect of user-defined thresholds and adaptive controller design parameters to the system performance, and discuss conditions to make the resulting command following performance error sufficiently small. An illustrative numerical example is …

Novel Layered Double Hydroxides-Hydroxyapatite/Gelatin Bone Tissue Engineering Scaffolds: Fabrication, Characterization, And In Vivo Study, Fateme Fayyazbakhsh, Mehran Solati-Hashjin, Abbas Keshtkar, Mohammad Ali Shokrgozar, Mohammad Mehdi Dehghan, Bagher Larijani

Mechanical and Aerospace Engineering Faculty Research & Creative Works

Developing Porous Biodegradable Scaffolds through Simple Methods is One of the Main Approaches of Bone Tissue Engineering (BTE). in This Work, a Novel BTE Composite Containing Layered Double Hydroxides (LDH), Hydroxyapatite (HA) and Gelatin (GEL) Was Fabricated using Co-Precipitation and Solvent-Casting Methods. Physiochemical Characterizations Showed that the Chemical Composition and Microstructure of the Scaffolds Were Similar to the Natural Spongy Bone. Interconnected Macropores Ranging over 100 to 600 Μm Were Observed for Both Scaffolds While the Porosity of 90 ± 0.12% and 92.11 ± 0.15%, as Well As, Young's Modulus of 19.8 ± 0.41 and 12.5 ± 0.35 GPa Were …

Solvent Based 3d Printing Of Biopolymer/Bioactive Glass Composite And Hydrogel For Tissue Engineering Applications, Krishna Kolan, Yong Liu, Jakeb Baldridge, Caroline Murphy, Julie A. Semon, D. E. Day, Ming-Chuan Leu

Biological Sciences Faculty Research & Creative Works

Three-dimensional (3D) bioprinting is an emerging technology in which scaffolding materials and cell-laden hydrogels may be deposited in a pre-determined fashion to create 3D porous constructs. A major challenge in 3D bioprinting is the slow degradation of melt deposited biopolymer. In this paper, we describe a new method for printing poly-caprolactone (PCL)/bioactive borate glass composite as a scaffolding material and Pluronic F127 hydrogel as a cell suspension medium. Bioactive borate glass was added to a mixture of PCL and organic solvent to make an extrudable paste using one syringe while hydrogel was extruded and deposited in between the PCL/borate glass …

Pore Resolved Simulations Of Char Particle Gasification, Greg Hingwah Fong

Master's Theses (2009 -)

Coal is a significant source of energy in today’s world and many studies have been conducted in order to better understand and optimize its use. To address greenhouse effects associated with coal combustion, cleaner methods for harnessing its energy are being explored. One such method is gasification, a process which converts coal into syngas, a mixture consisting primarily of H2 and CO. Syngas can be used to generate electricity or to produce hydrocarbons that can be used as fuels. To better understand and optimize the process, simulations can be used to study the gasification of individual porous char particles that …