Engineering Commons^™

Correlating The Physicochemical Properties Of Magnesium Stearate With Tablet Dissolution And Lubrication, Julie L. Calahan

Theses and Dissertations--Pharmacy

Magnesium stearate (MgSt) is the most commonly used pharmaceutical excipient and is present in over half the tablet formulations on the market. In spite of its popularity as an effective lubricant, it has been repeatedly recognized that there is significant variability between MgSt samples, which can cause inconsistent lubrication between batches of MgSt. The hypothesis of this research is that the batch-to-batch variability in tablet lubrication and dissolution observed in tablet formulations containing different MgSt samples can be correlated with differences in MgSt physicochemical properties (fatty acid salt composition, crystal hydrate form, particle size and surface area). Developing correlations between …

Characterization Of Rare Earth Elements In The Illinois Basin Coals, Alireza Valian

Theses and Dissertations--Mining Engineering

The purpose of this study is to characterize the distribution and occurrence of rare earth elements (REEs) in the coal and coal-related material from the Illinois Basin. For characterizing the distribution of REEs, 17 core samples were investigated from various parts in the basin. Also, several individual samples from coal preparation plants and isolated geological occurrences were included in the study. In result, the average REE concentrations were calculated on a bed-to-bed basis, although the distribution of REEs in the coal beds was found laterally and vertically heterogeneous. A number of trends were found that describe the variations. Most importantly, …

Investigation Into Mine Pillar Design And Global Stability Using The Ground Reaction Curve Concept, Ravi Chandan Ray

Theses and Dissertations--Mining Engineering

Pillars form an important support structure in any underground mine. A bulk of the overburden load is borne by the mine pillars. Thus, the strength of pillars has been a subject of detailed research over more than 6 decades. This work has led to the development of largely empirical pillar design formulations that have reduced the risk of pillar failures and mine collapse. Current research, however, has drawn attention to the fact that some of the assumptions used in the development of conventional pillar design methodologies are not always valid. Conventional pillar design methodology assumes that the pillars carry the …

Numerical Approximation Of The Ground Reaction And Support Reaction Curves For Underground Limestone Mines, Jesus Castillo Gomez

Theses and Dissertations--Mining Engineering

Pillar stability has been a matter of study for the last 70 years. The determination of pillar strength had taken different solutions and approaches over that time. This research has led to numerous empirical formulations that have reduced the number of pillar failures worldwide. However, new numerical approaches are being studied. In the last 20 years, the Ground Reaction Curve concept has been examined as a way of understanding the convergence of the rock-mass. Although the Ground Reaction Curve was first introduced in the civil tunneling industry, several authors have introduced the Ground Reaction Curve concept as an approach for …

Numerical And Experimental Studies Of Blocked Force Determination On An Offset Interface For Plate And Shell Structures And Duct Acoustic Systems, Keyu Chen

Theses and Dissertations--Mechanical and Aerospace Engineering

Blocked force determination is an alternative to the more routine method of inverse force determination using classical transfer path analysis. One advantage of determining blocked forces is that there is no need for the source to be detached or isolated from the system. Another advantage is that calculated blocked forces are appropriate when modifications are made on the receiver side of the interface. This insures that the blocked forces are suitable for utilization in analysis models where receiver system modifications are considered. Difficulties in using the approach arise when interface locations are difficult to instrument. This thesis demonstrates that blocked …

Coarse-Grained Dynamically Accurate Simulations Of Ionic Liquids At Vacuum-Interface, Tyler D. Stoffel

Theses and Dissertations--Mechanical and Aerospace Engineering

Ionic liquids, possessing improved properties in many areas of technical application, are excellent candidates as components in development of next-generation technology, including ultra-high energy batteries. If they are thus applied, however, extensive interfacial analysis of any selected ionic configuration will likely be required. Molecular dynamics (MD) provides an advantageous route by which this may be accomplished, but can fall short in observing some phenomena only present at larger time/length scales than it can simulate. Often times this is approached by coarse-graining (CG), with which scope of simulation can be significantly increased. However, coarse-grained MD systems are generally known to produce …

Modeling Thin Fluid Film On A Rotary Bell, Mark Doerre

Theses and Dissertations--Mechanical and Aerospace Engineering

A component of the mission in the Institute of Research for Technology Development at the University of Kentucky is advancing research and development and bringing it to the factory floor for continuous improvement. This dissertation delves into the art and science of rotational fluid mechanics in the context of rotary bell atomizers. One outcome proves that an approximation for calculating fluid film thicknesses on high-speed spinning surfaces inferred while working in cylindrical and spherical coordinate systems can be applied to an arbitrary bell profile. However, the analytical limits of this approximation were not investigated. In all cases, a restriction exists …

Molten Aluminum Capillary Hole-Filling, Cheng-Nien Yu

Theses and Dissertations--Mechanical and Aerospace Engineering

The presence of micrometeoroids and space debris in open space raises the question of a mitigation of the damage caused by a possible impact on the man-made structures such as space shuttles, satellites, and the International Space Station. A method achieving metallic sealed hole would be of an interest for development. This dissertation studies a surface tension driven capillary filling/sealing phenomenon in a controlled atmosphere brazing process of aluminum. The filled vs. non-filled results are predictable using minimization of energy, which shows that the outcomes depend heavily on prescribed configurations of the hole. Equilibrium models show excellent agreement with experimental …

Electrophoresis In Heterogeneous Hydrogels And Applications In Surface Patterning, Ning Ge

Theses and Dissertations--Mechanical and Aerospace Engineering

The creation of chemical micropatterns on surfaces makes it possible to add unique chemical functionality to surfaces, modifying properties such as wettability, or even adding the ability to selectively bind other molecules. The creation of biochemical surface patterning in particular is useful in a variety of fields including tissue engineering and highthroughput drug screening. There are many existing surface patterning techniques which focus on precise control over the patterned geometry, even down to submicron scale features, but they do not allow local control over chemical concentration. So the results are high resolution patterns with binary concentration. There are also existing …

Stress Generation In Ni50.3Ti29.7Hf20 Shape Memory Alloys, Utsav Shah

Theses and Dissertations--Mechanical and Aerospace Engineering

Shape memory alloys such as NiTiHf and NiTi have the ability to generate large recovery stresses when they are constrained after pre-straining and then heated above their Austenite Finish Temperature (A_f). In this work Ni_49.9Ti_50.1 (at.%), the most well-known SMA with impressive shape memory properties but limited temperature range and Ni_50.3Ti_29.7Hf₂₀, a promising high temperature shape memory alloy, were characterized to reveal their stress generation capabilities. The effects of pre-straining on stress generation were investigated via martensite reorientation method of NiTi and NiTiHf alloys by loading the samples till …

Filtered-Dynamic-Inversion Control For Unknown Minimum-Phase Systems With Unknown Relative Degree, Sumit Suryakant Kamat

Theses and Dissertations--Mechanical and Aerospace Engineering

We present filtered-dynamic-inversion (FDI) control for unknown linear time-invariant systems that are multi-input multi-output and minimum phase with unknown-but-bounded relative degree. This FDI controller requires limited model information, specifically, knowledge of an upper bound on the relative degree and knowledge of the first nonzero Markov parameter. The FDI controller is a single-parameter high-parameter-stabilizing controller that is robust to uncertainty in the relative degree. We characterize the stability of the closed-loop system. We present numerical examples, where the FDI controller is implemented in feedback with mathematical and physical systems. The numerical examples demonstrate that the FDI controller for unknown relative degree …

The Influence Of Cryogenic Machining On Surface Integrity And Functional Performance Of Titanium Alloys For Biomedical And Aerospace Applications, Ying Sun

Theses and Dissertations--Mechanical and Aerospace Engineering

The excellent properties of titanium alloys such as high strength, as well as good corrosion and fatigue resistance are desirable for the biomedical and aerospace industry. However, the same properties that make titanium alloys desirable in high-performance applications also make these space-age materials “difficult-to-machine” materials, as the titanium alloys exhibit high cutting temperatures because of their high strength and low thermal conductivity.

Cryogenic machining is a severe plastic deformation (SPD) processes which uses liquid nitrogen as the coolant to take away the heat generated during machining in a relatively short time. Cryogenic machining can significantly reduce the cutting temperatures at …

Influence Of Size Effects On Surface Generation During Finish Machining And Surface Integrity In Ti-6al-4v, Ian S. Brown

Theses and Dissertations--Mechanical and Aerospace Engineering

Finish machining is an essential manufacturing process that is used to enhance the mechanical characteristics of critical components. The deformation that occurs at the tool and workpiece interface in finish machining significantly affects a host of component properties, commonly referred to as “surface integrity” properties. Surface roughness is a machining deformation-affected characteristic that is of high relevance in contemporary manufacturing. However, over recent decades it has been made clear that the material properties of the deformed surface layers are relevant to component performance as well. Predicting the overall surface quality of a machined component is of great relevance to the …

Safety Concepts For Every Ride: A Statistical Ensemble Simulation To Mitigate Rotational Falls In Eventing Cross Country, Shannon Wood

Theses and Dissertations--Mechanical and Aerospace Engineering

Rotational falls are the leading cause of death and serious injury in the equestrian sport of eventing. Previous studies to develop safety devices used physical models representing one or at most several physical situations leading to different designs and no common understanding. In this thesis, a statistical ensemble model is developed and applied to generate and evaluate 10,000 different situations that might potentially lead to rotational falls. For accurate statistical representation of the horse and rider inertia distributions, measurements of over 400 training or competing horses and riders were recorded and incorporated. Video was recorded of 218 total competitors approaching …

Capillary Flow Of Liquid Aluminum Alloy In Wetting And Wetting/Non-Wetting Systems, Yangyang Wu

Theses and Dissertations--Mechanical and Aerospace Engineering

In this dissertation, the capillary flow of liquid aluminum alloy in both wetting and wetting/non-wetting systems is investigated.

The impact of gravity and surface topography on the capillary flow has been studied in a wetting/non-wetting assembly (an AA3003/Al₂O₃ wedge-tee configuration). The research includes (i) kinetics of liquid Al-Si-K_xAl_yF_z alloy triple line movements and dynamic macro advancing and receding contact angles and (ii) free surface profiles of the molten alloy driven by surface tension and impacted by gravity. A trade-off between the surface tension and gravity force has been found by calculating the …

Flame Stabilization Of A Premixed Jet In Vitiated Coflow, Tyler Owens

Theses and Dissertations--Mechanical and Aerospace Engineering

Premixed staged combustion in gas turbine engines can reduce emissions by lowering peak flame temperatures but can also lead to different stability characteristics when compared to traditional combustors. High pressure ratio and subsequently high temperatures can lead to conditions suitable for both autoignition and premixed flame propagation in an environment where spatial fuel/air variations are present.

An experimental facility which issues a premixed jet into a coflowing vitiated mixture was studied to examine the stability behavior, resulting in a lifted flame. The effective ignition delay observed flame was much greater than homogeneous ignition delay calculations for the same conditions. It …

Development And Application Of Novel Sound Absorbers, Weiyun Liu

Theses and Dissertations--Mechanical and Aerospace Engineering

The sound absorbers in most common use today are porous materials like fibers and foams. This work examines three alternatives to porous absorbers: microperforated panels, acoustic fabrics, and additively manufactured absorbers. The research is a combination of design, measurement and characterization of their properties, and analysis.

Microperforated panels are thin metallic or plastic panels with sub-millimeter size holes or perforations. Sound absorption can be tuned by adjusting the spacing between the panel and a cavity behind the panel. Several different configurations were considered where the geometry behind the panel was divided up into channels of varying length and cross-sectional area. …

Development Of Micro-Scale High Aspect Ratio Patterned Features With Electroless Nickel Plating, Lorli Smith

Theses and Dissertations--Mechanical and Aerospace Engineering

This thesis describes a novel method designed to pattern high aspect ratio metallic microscale features using a modified photolithography and electroless nickel plating process. This method utilizes modified photolithography techniques to create a polymer mold that is used to control the location of metal deposition on substrate during electroless nickel plating. In order to generate high aspect ratio mold features, a multiple spin-step process was developed to deposit thick layers of SU-8 photoresist, and inclined lithography was also used to generate tapered sidewalls that could help aid mold removal after plating. Results from electroplating experiments were evaluated using a Zygo …

Development Of Universal Solver For High Enthalpy Flows Through Ablative Materials, Umran Duzel

Theses and Dissertations--Mechanical and Aerospace Engineering

Atmospheric entry occurs at very high speeds which produces high temperature around the vehicle. Entry vehicles are thus equipped with Thermal Protection Systems which are usually made of ablative materials. This dissertation presents a new solver that models the atmospheric entry environment and the thermal protection systems. In this approach, both the external flow and the porous heat shield are solved using the same computational domain. The new solver uses the Volume Averaged Navier-Stokes Equations adapted for hypersonic non-equilibrium flow, and is thus valid for both domains. The code is verified using analytical problems, set of benchmarks and also a …

Bacterial Cell Wall Characterization Via Atomic Force And Confocal Microscopy, Joree Sandin

Theses and Dissertations--Mechanical and Aerospace Engineering

Poor oral hygiene is a severe global health issue, with about 44% of the Earth’s population suffering from untreated tooth decay, accounting for over $100 billion dollars spent on dental services per year in the United States, alone. Manual treatments, such as brushing, flossing, or swishing with antiseptic rinse are the main ways to alleviate harmful bacteria that cause these oral health problems. Streptococcus mutans (S. mutans) is a group of highly antibiotic, Gram-positive bacteria that heavily contribute to oral cavities, plaque build-up, and potential loosening or loss of dental implants if a biofilm develops. Currently, the mechanism …

Carbon Oxidation At The Atomic Level: A Computational Study On Oxidative Graphene Etching And Pitting Of Graphitic Carbon Surfaces, Simon Schmitt

Theses and Dissertations--Mechanical and Aerospace Engineering

In order to understand the oxidation of solid carbon materials by oxygen-containing gases, carbon oxidation has to be studied on the atomic level where the surface reactions occur. Graphene and graphite are etched by oxygen to form characteristic pits that are scattered across the material surface, and pitting in turn leads to microstructural changes that determine the macroscopic oxidation behavior. While this is a well-documented phenomenon, it is heretofore poorly understood due to the notorious difficulty of experiments and a lack of comprehensive computational studies. The main objective of the present work is the development of a computational framework from …

Fabrication And Characterization Of Nickel Plated Micro-Resonators For Noncommutative Orientation Control In Microrobots, Marc Manheim

Theses and Dissertations--Mechanical and Aerospace Engineering

This thesis describes a procedure for fabricating arrays of microstructures out of SU-8 photoresist and nickel, which was developed with the goal of yielding microrobots capable of 1D rotation byway of magnetically-induced beam vibration that could be used for non-commutative orientation control. Several multi-layer geometries were designed, fabricated, tested and refined. In this process, micro-adhesion of multiple SU-8 layers was also studied. A method for depositing nickel via electroless plating was also developed, tested and characterized. While no microrobots were shown to produce rotation, the final results included beams that were capable of magnetically-induced vibration when subjected to an AC …

Expanded Predictive Equation For Dc Arc-Flash Incident Energy In 125v Battery Systems, Austin Gaunce

Theses and Dissertations--Electrical and Computer Engineering

Arc-flash is a dangerous phenomenon that can occur during an arcing fault in an electrical system. People nearby may be subjected to extreme heat, light, pressure, and sound. Research regarding arc-flash has focused primarily on AC arc-flash due to the prevalence of AC electricity in the grid. However, the grid has begun to integrate more DC electrical sources as a result of decentralization efforts and environmental concerns. The increased proliferation of DC electrical sources demands research into DC arc-flash to assess the hazard as low-voltage DC sources have already become commonplace. Some DC arc-flash models have been produced to estimate …

Ecosystem Of Bagged Grain Stored Under Naturally Ventilated Warehouse: Analysis And Modelling, Michael Ayodele Omodara

Theses and Dissertations--Biosystems and Agricultural Engineering

Grain in Africa and indeed most developing parts of the world are stored in polypropylene or jute bags arranged in stacks of varied dimensions in naturally ventilated warehouses. This practice is, however, associated with high postharvest losses due to poor temperature and moisture management during storage. This constitutes a major economic and food security challenge in these countries. Therefore, this study characterizes changes in moisture content and temperature occurring in a stack of bagged corn by determining the permeability of bag materials that influence moisture transfer and developing a mathematical model of heat and mass transfer which incorporates the unique …

Characterizing And Predicting The Antimicrobial Properties Of Lignin Derivatives, Ryan Kalinoski

Theses and Dissertations--Biosystems and Agricultural Engineering

Due to the overuse of antibiotics in our society, there has been a steady rise in highly antimicrobial-resistant bacteria in the last decade. This has created a renewed interest in natural phenolic compounds for antimicrobial discovery amongst the scientific community. To this end, lignin is the most abundant naturally occurring phenolic polymer on earth and has already been known to have antimicrobial properties due to its polyphenolic structure. In addition, lignin is considered a major waste product for lignocellulosic biorefineries, and its valorization into value-added products will generate extra profit for a biorefinery, making biofuels less expensive, increasing their marketability …

Physicochemical Characterization, Structural Determination, And Molecular Dynamic Modeling Of Proso Millet Proteins For Enhanced Food Functionality, Felix Akharume

Theses and Dissertations--Biosystems and Agricultural Engineering

More than one-third of Americans today incorporate plant-based protein into their diet and about 40% believed that plant-based protein is healthier than animal protein, especially Millennials. The increasing global demand for plant-based proteins driven by the high cost of animal proteins, consumers’ desire for lean protein, vegetarianism, and the need for more sustainable green protein products have necessitated research into alternate emerging and underutilized sources of protein to complement or supplement the major plant protein in the market- soy, pea, and gluten. Therefore, this dissertation is focused on the valorization of the proteins in proso millet. Specifically, this work focused …

Effects Of Watershed Disturbances And River-Tributary Confluences On Sedimentation Dynamics In The Upper Ohio River Basin, Ciara Pickering

Theses and Dissertations--Biosystems and Agricultural Engineering

Harmful algal blooms (HABs) are of increasing concern in the Ohio River Basin. Fine sediment dynamics in riverine environments are increasingly recognized to play important roles in proliferation and toxicity of Microcystis blooms. Further, the fate of sediment at confluences of tributaries and the main river system are important zones for sediment retention and transient storage. The objective of this study was to improve understanding of watershed sediment loading dynamics and backwater inundation influencing sedimentation within confluence watersheds. The study site is the Fourpole Creek watershed in Huntington, WV which is a disturbed forested watershed impacted by a backwater confluence …

The Optimum Design Of A Vacuum-Compatible Manipulator To Calibrate Space Based Ultraviolet Imagers, Jason L. Grillo

Master's Theses

Recent discoveries in geospace science have necessitated the design of compact UV imaging instruments to make space-based observations from multiple vantage points. The miniaturized ultraviolet imager (MUVI) instrument from the Space Sciences Laboratory (SSL) at UC Berkeley is under development to facilitate such discoveries on a wider scale. This thesis documents the design, integration, and characterization of a vacuum compatible manipulator to calibrate the MUVI instrument inside the UV thermal vacuum chamber at SSL. Precision linear and rotation stages were implemented with custom mounting plates to achieve four degrees of freedom. Optical components were installed to imitate the MUVI instrument …

Opendrop Software Development, Jiajun Guan

Electrical Engineering

To be able to transfer and mix solutions more efficiently and accurately during biology experiments, the Electrical Engineering department at Cal Poly University is planning to purchase or engineer the OpenDrop device. The OpenDrop device uses electro-wetting technology to control the movement of small droplets of water on a planar electrode array to transport and mix different solutions. This device is an open-source project and could be purchased online through the GaudiLab. The basic code of the system could be found in GitHub. With this code as a reference, the goal of this senior project is to develop the firmware, …

Provably Trustworthy And Secure Hardware Design With Low Overhead, Qutaiba Alasad

Electronic Theses and Dissertations, 2020-2023

Due to the globalization of IC design in the semiconductor industry and outsourcing of chip manufacturing, 3PIPs become vulnerable to IP piracy, reverse engineering, counterfeit IC, and hardware Trojans. To thwart such attacks, ICs can be protected using logic encryption techniques. However, strong resilient techniques incur significant overheads. SCAs further complicate matters by introducing potential attacks post-fabrication. One of the most severe SCAs is PA attacks, in which an attacker can observe the power variations of the device and analyze them to extract the secret key. PA attacks can be mitigated via adding large extra hardware; however, the overheads of …