Engineering Commons^™

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.

Microdischarges Utilized In Portable Gas Sensing And Their Atmospheric Contaminants, Colin H. Sillerud

Chemical and Biological Engineering ETDs

Portable applications of microdischarges such as the chemical detection, remediation of gaseous wastes, or the destruction of volatile organic compounds will mandate operation in the presence of contaminant species. This work examines the temporal evolution of microdischarge optical and ultraviolet emissions during pulsed operation by experimental methods. By varying the pulse length of a microdischarge initiated in a 4-hole silicon microcavity array operating in a 655 Torr ambient primarily composed of Ne, we were able to measure the emission growth rates for different contaminant species native to the discharge environment as a function of pulse length. It was found that …

Size And Shape Distributions Of Primary Crystallites In Titania Aggregates, Eric A. Grulke, Kazuhiro Yamamoto, Kazuhiro Kumagai, Ines Häusler, Werner Österle, Erik Ortel, Vasile-Dan Hodoroaba, Scott C. Brown, Christopher Chan, Jiwen Zheng, Kenji Yamamoto, Kouji Yashiki, Nam Woong Song, Young Heon Kim, Aleksandr B Stefaniak, D. Schwegler-Berry, Victoria A. Coleman, Åsa K. Jämting, Jan Herrmann, Toru Arakawa, Woodrow W. Burchett, Joshua W. Lambert, Arnold J. Stromberg

Chemical and Materials Engineering Faculty Publications

The primary crystallite size of titania powder relates to its properties in a number of applications. Transmission electron microscopy was used in this interlaboratory comparison (ILC) to measure primary crystallite size and shape distributions for a commercial aggregated titania powder. Data of four size descriptors and two shape descriptors were evaluated across nine laboratories. Data repeatability and reproducibility was evaluated by analysis of variance. One-third of the laboratory pairs had similar size descriptor data, but 83% of the pairs had similar aspect ratio data. Scale descriptor distributions were generally unimodal and were well-described by lognormal reference models. Shape descriptor distributions …

Shortest Path Problem Under Trapezoidal Neutrosophic Information, Florentin Smarandache, Said Broumi, Mohamed Talea, Assia Bakali

Branch Mathematics and Statistics Faculty and Staff Publications

In this research paper, a new approach is proposed for computing the shortest path length from source node to destination node in a neutrosophic environment. The edges of the network are assigned by trapezoidal fuzzy neutrosophic numbers. A numerical example is provided to show the performance of the proposed approach.

A Critical Path Problem Using Triangular Neutrosophic Number, Florentin Smarandache, Mai Mohamed, Yongquan Zhou, Mohamed Abdel-Baset

Branch Mathematics and Statistics Faculty and Staff Publications

The Critical Path Method (CPM) is one of several related techniques for planning and managing of complicated projects in real world applications. In many situations, the data obtained for decision makers are only approximate, which gives rise of neutrosophic critical path problem. In this paper, the proposed method has been made to find the critical path in network diagram, whose activity time uncertain. The vague parameters in the network are represented by triangular neutrosophic numbers, instead of crisp numbers. At the end of paper, two illustrative examples are provided to validate the proposed approach.

Inertization, Utilization, And Safe Disposal Of Incineration Residues, Anil Mehrotra

Civil & Environmental Engineering Projects for D. Eng. Degree

Combustion of coal or Municipal Solid Waste (MSW) caused air pollution and produces solid residues which contain high levels of toxic elements. The toxic characteristics of residues generated from combustion of MSW in waste-to-energy plants are strictly controlled by Federal and State Waste Management Regulations. According to Resource Conservation and Recovery Act (RCRA), residue generated from combustion of MSW is considered hazardous and must be tested according to EPA Toxic Characteristics Leaching Procedure (TCLP) Method 1311 and suitably treated for its safe disposal to landfills. Experiments with various treatment chemicals as primary independent variable had earlier been conducted by several …

Human Factors For Small Net Habitable Volume: The Case For A Close-Quarter Space Habitat Analog, Victor Kitmanyen, Timothy J. Disher, Ryan L. Kobrick, Jason P. Kring

Publications

Increasing efforts in sending humans to Mars calls for greater considerations of the ways in which vehicle and habitat design can influence crew performance and behavioral health.

Perception And Reality: Measuring Digital Skills In Singapore, Swapna Gottipati

Research Collection School Of Computing and Information Systems

ICDL Asia carried out a digital literacy study in Singapore, looking at an essential skill for everyday life. The goal of the study was to discover the digital skills gaps among young people in Singapore. Singapore is considered to be a digitally advanced country where young people have access to the latest technology and gadgets. At the same time, it is imperative for young people to possess relevant digital skills for a future-ready and healthy economy. The studies consisted of two key parts: self-assessment and practical assessment of digital skills. Our findings show that, though the digital native fallacy exists …

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 …

Investigation Of Passengers’ Intentions To Use High-Speed Rail And Low-Cost Carriers In China, Jing Yu Pan

Doctoral Dissertations and Master's Theses

With a large population, China is an ideal market for high-speed rail (HSR) and low-cost carrier (LCC) services. While HSR has gained substantial market share in China over the past decade, LCCs have achieved only limited market penetration. The potential growth of LCCs in China, however, is promising given the growing travel demand and government policy support. As LCCs expand their service in the domestic market, they are likely to become a strong competitor of HSR. The potential competition between LCCs and HSR justifies the research of passengers’ behavioral intentions to use HSR and LCCs in China.

This research focused …

Design Of Variable Stiffness Composite Panels For Maximum Strength, Joel P. Hurley

Doctoral Dissertations and Master's Theses

The purpose of this research is to explore the design of variable stiffness composites and develop an automated framework to model, analyze and optimize these structures. Variable stiffness composites have been shown to exhibit increased strength and stiffness over traditional constant stiffness composites by tailoring fiber orientations for specific load conditions. This is achieved by allowing the fiber orientation to vary spatially across the design domain. Motivation for new design methods is driven by the recent advancements in composite additive manufacturing, such as automated fiber placement machines, which allow fiber reinforcements to be placed along prescribed trajectories during manufacturing. Through …

Numerical Study Of Mixing Of A Supercritical Jet In A Supercritical Environment, Neil Sullivan

Doctoral Dissertations and Master's Theses

A numerical simulation campaign is conducted to better elucidate flow physics and modeling requirements of a supercritical (SC) nitrogen jet injected into a tank of quiescent SC nitrogen. The goals of this work are twofold: to inform the design of injectors and combustion chambers for use in the direct-fired supercritical CO2 (s-CO2) power generation cycle and cryogenic liquid propellant rockets, and to investigate the extent to which meaningful flow characterization can be achieved with computationally expedient methods, using commercial software. Reynolds-Averaged Navier-Stokes (RANS) and Large Eddy Simulation (LES) approaches are used in STAR-CCM+ versions 10.06.010 and 12.02.011. Jet disintegration is …

Progress Towards Competitive Iii-V Infrared Detectors: Fundamental Material Characterization And Techniques, Emil A. Kadlec

Electrical and Computer Engineering ETDs

Measurement of recombination mechanisms provides critical feedback on the material quality of semiconductors. Strained layer type-II superlattices (T2SLs) have seen a recent increase in interest as they possess intriguing properties making them prime candidates for use as infrared detectors. As T2SL-based detectors approach the performance of industry-standard Hg_1-xCd_xTe photodetectors, measurement of the carrier lifetime is becoming increasingly important. A comparison of the lifetime measurement techniques time-resolved photoluminescence, frequency-modulated photoluminescence, time-resolved microwave reflectance, and frequency-modulated conductance is made. Although photoluminescence-based measurement techniques are more common in literature, it is shown that the microwave reflectance-based measurement technique is …

Metallographic Analysis And Electrical Resistivity Of The 1045 Steel After Being Heat-Treated, M Quiroga Agurto, E Medrano Atencio, F Américo Reyes Navarro, J G Miranda Ramos

Journal of Metals, Materials and Minerals

Herein, it was studied the structural evolution of the AISI 1045 steel water-quenched and oilquenched, respectively, from a temperature higher than the critical to various temperatures between 800 and 820°C. The two quenching media were used at 16.5°C. Microstructural variations occurred in the quenched 1045 steel. Also, by using the four-terminal sensing, it was measured the evolution of the electrical resistivity of the quenched samples; it was found that quenching at different temperatures provoked a complex behavior. It was noticed a major increase in the electrical resistivity in the case of water-quenched samples. Besides, when compared samples before and after …

Optimal Control Methods For Missile Evasion, Ryan W. Carr

Theses and Dissertations

Optimal control theory is applied to the study of missile evasion, particularly in the case of a single pursuing missile versus a single evading aircraft. It is proposed to divide the evasion problem into two phases, where the primary considerations are energy and maneuverability, respectively. Traditional evasion tactics are well documented for use in the maneuverability phase. To represent the first phase dominated by energy management, the optimal control problem may be posed in two ways, as a fixed final time problem with the objective of maximizing the final distance between the evader and pursuer, and as a free final …

Perspective: The Physics, Diagnostics, And Applications Of Atmospheric Pressure Low Temperature Plasma Sources Used In Plasma Medicine, M. Laroussi

Electrical & Computer Engineering Faculty Publications

Low temperature plasmas have been used in various plasma processing applications for several decades. But it is only in the last thirty years or so that sources generating such plasmas at atmospheric pressure in reliable and stable ways have become more prevalent. First, in the late 1980s, the dielectric barrier discharge was used to generate relatively large volume diffuse plasmas at atmospheric pressure. Then, in the early 2000s, plasma jets that can launch cold plasma plumes in ambient air were developed. Extensive experimental and modeling work was carried out on both methods and much of the physics governing such sources …

Consumers’ Willingness To Fly In Augmented Cognition Equipped Aircraft, Eric Schanafelt

Theses and Dissertations

Current advancements in the field of Augmented Cognition have garnered attention from the aviation industry. Equipping flight management systems with Augmented Cognition is a possibility in the near future as the result of recent computing breakthroughs. The purpose of this study was to determine to what extent gender, country of origin and condition of Augmented Cognition affect consumers willingness to fly. To further understand the consumer's decision-making process the participant’s willingness to fly measured through affect (emotion), represented through the six universal facial expressions, (anger, disgust, fear, happiness, sad, and surprise) (Ekman & Friesen, 1971). This study surveyed participants from …

Reply To Comment By Fred L. Ogden Et Al. On "Beyond The Scs-Cn Method: A Theoretical Framework For Spatially Lumped Rainfall-Runoff Response", Mark Bartlett, Anthony J. Parolari, Jeffrey Mcdonnell, Amilcare Porporato

Civil and Environmental Engineering Faculty Research and Publications

Though Ogden et al. list several shortcomings of the original SCS-CN method, fit for purpose is a key consideration in hydrological modelling, as shown by the adoption of SCS-CN method in many design standards. The theoretical framework of Bartlett et al. [2016a] reveals a family of semidistributed models, of which the SCS-CN method is just one member. Other members include event-based versions of the Variable Infiltration Capacity (VIC) model and TOPMODEL. This general model allows us to move beyond the limitations of the original SCS-CN method under different rainfall-runoff mechanisms and distributions for soil and rainfall variability. Future research should …

Development Of Adjustment Factors For Mepdg Pavement Responses Utilizing Finite-Element Analysis, Osman Erman Gungor, Imad L. Al-Qadi, Angeli Gamez, Jaime Hernandez

Civil and Environmental Engineering Faculty Research and Publications

The Mechanistic-empirical pavement design guide (MEPDG) provides theoretically superior methodology, as compared with its predecessor, for the design and analysis of pavement structures. The mechanistic part refers to simulating pavement–tire interaction to calculate critical responses within pavement. The empirical part means prediction of pavement distress propagation over time using transfer functions that link a critical pavement response to a particular pavement distress. The mechanistic part of MEPDG simulates tire–pavement interaction in three steps: subdivision of pavement layers; complex modulus calculation at the middepth of each sublayer, considering velocity and temperature; and running the multilayered elastic theory (MLET) software, …

Effectiveness Of Indoor Plants For Passive Removal Of Indoor Ozone, Omed A. Abbass, David J. Sailor, Elliott T. Gall

Mechanical and Materials Engineering Faculty Publications and Presentations

Indoor vegetation is often proposed as a passive approach for improving indoor air quality. While studies of outdoor environments indicate that vegetation can be an important sink of outdoor ozone, there is scant data in the literature concerning the dynamics of ozone uptake by indoor plants. This study determined ozone deposition velocities (v_d) for five common indoor plants (Peace Lily, Ficus, Calathia, Dieffenbachia, Golden Pothos). The transient v_d was calculated, using measured leaf areas for each plant, for exposures mimicking three diurnal cycles where ozone concentrations in chamber tests were elevated for 8 h followed by …

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 …

An Improved Method Of Arsenic (Iii) Removal By Reverse Osmosis Membrane, Yizhi Hou

Master's Theses (2009 -)

Arsenic is a Group 1 carcinogen as there is abundant research to support that ingestion of arsenic in drinking water and food can lead to liver, lung, kidney, or bladder cancer in humans. The recommend World Health Organization (WHO) arsenic standard in drinking water is 10 µg/L, while the Environmental Protection Agency's (EPA) Maximum Contaminant Level (MCL) of arsenic in drinking water is 10 µg/L. Globally, at least 40 million people face more than 10 µg/L arsenic contamination in their drinking water. As(III) (trivalent state, such as arsenite), and As(V) (pentavalent state, such as arsenates) are the dominant arsenic forms …

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 …

Evaluating Wall Shear Stress Indices To Uncover Stimuli For Restenosis And Malapposition In Stented Coronary Arteries, Ali A. Aleiou

Master's Theses (2009 -)

The cause of coronary artery neointimal thickening leading to restenosis in ~10% of drug-eluting stents is unknown. Although research suggests adverse values of traditional wall shear stress (WSS) indices may contribute, studies to date have not accounted for stent geometry, which dictates local WSS patterns influencing drug concentration. Recently proposed WSS indices such as WSS variability and WSS exposure time (WSSET) may shed further light on restenosis or, the opposite effect, resorption. The objective of this investigation was to locally evaluate traditional and recently proposed post-stenting metrics and their respective impact on restenosis or resorption. This study used de-identified data …

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.

Development Of Kinematic Templates For Automatic Pronunciation Assessment Using Acoustic-To-Articulatory Inversion, Deriq K. Jones

Master's Theses (2009 -)

Computer-aided pronunciation training (CAPT) is a subcategory of computer-aided language learning (CALL) that deals with the correction of mispronunciation during language learning. For a CAPT system to be effective, it must provide useful and informative feedback that is comprehensive, qualitative, quantitative, and corrective. While the majority of modern systems address the first 3 aspects of feedback, most of these systems do not provide corrective feedback. As part of the National Science Foundation (NSF) funded study “RI: Small: Speaker Independent Acoustic-Articulator Inversion for Pronunciation Assessment”, the Marquette Speech and Swallowing Lab and Marquette Speech and Signal Processing Lab are conducting a …

Deep Neural Networks As Time Series Forecasters Of Energy Demand, Gregory Merkel

Master's Theses (2009 -)

Short-term load forecasting is important for the day-to-day operation of natural gas utilities. Traditionally, short-term load forecasting of natural gas is done using linear regression, autoregressive integrated moving average models, and artificial neural networks. Many purchasing and operating decisions are made using these forecasts, and there can be high cost to both natural gas utilities and their customers if the short-term load forecast is inaccurate. Therefore, the GasDay lab continues to explore new ways to make better forecasts. Recently, deep neural networks (DNNs) have emerged as a powerful tool in machine learning problems. DNNs have been shown to greatly outperform …

An Analysis Of Testing Variables In Rapid Compression Machine Experiments, Jenna Ezzell

Master's Theses (2009 -)

There have been discrepancies noted with regards to experimental data from rapid compression machines (RCM). When data is compared from different RCM facilities, the ignition delay times are inconsistent when inspecting any particular temperature. Currently in publications, if these datasets are compared, the discrepancy is said to be due to heat loss, however this issue has yet to be examined more thoroughly. To determine what the root cause of this discrepancy is, four different fake RCM facilities were created and simulated. There were also different sets of initial conditions used to determine how this may affect the data. They were …

Development Of An Optimal Controller And Validation Test Stand For Fuel Efficient Engine Operation, Jack G. Rehn Iii

Master's Theses (2009 -)

There are numerous motivations for improvements in automotive fuel efficiency. As concerns over the environment grow at a rate unmatched by hybrid and electric automotive technologies, the need for reductions in fuel consumed by current road vehicles has never been more present. Studies have shown that a major cause of poor fuel consumption in automobiles is improper driving behavior, which cannot be mitigated by purely technological means. The emergence of autonomous driving technologies has provided an opportunity to alleviate this inefficiency by removing the necessity of a driver. Before autonomous technology can be relied upon to reduce gasoline consumption on …