Engineering Commons^™

Computations Of The Dynamic Fracture Of Plane Structures By The Extended Finite Element Method, Iman Asareh

Theses and Dissertations

Finite element methods for the simulation of dynamic fracture in plane structures are presented. The method is a modified extended finite element method (XFEM) for dynamic fracture simulations with a new methodology to construct the XFEM basis functions for discontinuities. In contrast to conventional XFEM in which the extended interpolation is defined to only capture the discontinuities, the proposed method describes the enrichment functions so that they reproduce both the discontinuities and the polynomial bases of sufficiently high order which are critical for finite element convergence. Such enrichment functions, by adopting the Duffy’s transformation, can be simply defined in terms …

Dynamic Simulation Of A Solar Powered Hybrid Sulfur Process For Hydrogen Production, Satwick Boddu

Theses and Dissertations

The Hybrid Sulfur process is a thermo-electrochemical cycle used to produce hydrogen from water. The process requires a high temperature energy source for H2SO4 decomposition with temperature reaching 800°C. This step is followed by SO2 - depolarized water electrolysis. Using solar energy as the high temperature energy source allows for efficient environmentally friendly production of hydrogen. This method is an alternative to traditional photovoltaic electrolysis for hydrogen production. Making the process economically competitive is a major challenge. Operating the process with changes in the availability of solar energy also increases process complexity. The dependence of the process on solar energy …

Impact Of Plasma Jet Geometry On Residence Times Of Radical Species, James Lalor, Laurence Scally, Patrick J. Cullen, Vladimir Milosavljevic

Articles

Numerous electrode geometries and power supplies, both commercial and in-house, have been employed for the generation of low-temperature atmospheric plasma jets. In this work, the development and operation of a 12 jet nonthermal atmospheric plasma system is presented. The study is based on optical spectroscopy as a diagnostic method due to its nonintrusive nature. A key focus of this study was the material selection (conductive and nonconductive), with several polymers screened for the jet design leading to polyacetal as the choice material. Their results are compared with other atmospheric plasma jet systems. The results show a significant increase in residence …

Generating Adversarial Attacks For Sparse Neural Networks, Jack H. Chen, Walt Woods

Maseeh Summer Undergraduate Research Experience

Neural networks provide state-of-the-art accuracy for image classification tasks. However traditional networks are highly susceptible to imperceivable perturbations to their inputs known as adversarial attacks that drastically change the resulting output. The magnitude of these perturbations can be measured as Mean Squared Error (MSE). We use genetic algorithms to produce black-box adversarial attacks and examine MSE on state-of-the-art networks. This method generates an attack that converts 90% confidence on a correct class to 50% confidence of a targeted, incorrect class after 2000 epochs. We will generate and examine attacks and their MSE against several sparse neural networks. We theorize that …

Early Emerging Pathogen Detection, Mackenzie Wangenstein

Maseeh Summer Undergraduate Research Experience

A supervised learning technique was employed to identify emerging pathogen species. Portland State University has partnered with the University of New Mexico to take encodings of unknown pathogen molecular structures to determine emerging species.

Hydrogeology And Water Management In The Arkwright Underground Coal Mine, Pittsburgh Seam, Northern West Virginia, Bryant D. Mountjoy

Graduate Theses, Dissertations, and Problem Reports (ETD)

Arkwright #1 is a closed underground mine in the Pittsburgh coal seam near Morgantown, West Virginia USA. Arkwright shares perimeter boundaries/barriers with three other closed Pittsburgh seam mines (Osage #3, Jordan #93, Federal #1) and is partially overlain by flooded Sewickley seam mines, 25 m above it. This mine is significant primarily because it manages and treats water diverted from nearly 20 other closed mines over a 600 square kilometer area. This study examines water levels, pump records, and mine maps to describe the hydrogeology of Arkwright Mine. After closure in 1995, Arkwright and the adjacent northern Osage mines began …

Tortuosity Calculations, Blood Flow Simulations, And Mechanical Testing Of Mouse Aortae, Shawn Pavey, Jessica Wagenseil

Undergraduate Research Symposium Posters

Aortic aneurysms can lead to wall rupture or dissection, which are both deadly occurrences. The risk of developing problematic aneurysms increases with age, making them a growing concern in the USA’s aging population. Thoracic Aortic Aneurysm (TAA) treatment is highly effective if the TAA is diagnosed in time, however current surgical guidelines catch less than half of fatal TAA cases. Tortuosity (related to vessel length divided by the straight distance between two points of interest) has been proposed as a supplement to diameter based diagnosis of severity of TAA progression. This study aimed to confirm the validity of that proposal …

Kentucky Traffic Collision Facts 2017, Eric R. Green, Paul A. Ross, Christopher L. Blackden, Kentucky State Police

Kentucky Transportation Center Research Report

KENTUCKY’S TRAFFIC COLLISION FACTS report is based on collision reports submitted to the Kentucky State Police Records Branch. As required by Kentucky Revised Statutes 189.635, “every law enforcement agency whose officers investigate a vehicle accident of which a report must be made...shall file a report of the accident...within ten days after investigation of the accident upon forms supplied by the bureau.” The stated purpose of this requirement is to utilize data on traffic collisions for such purposes as will improve the traffic safety program in the Commonwealth. Data contained in this report are based solely on the observations and judgements …

Real-Time Communication In Wireless Sensor Networks, Jeongcheol Lee, Babar Shah, Giovanni Pau, Javier Prieto, Ki Il Kim

All Works

No abstract provided.

Energy-Efficient Region Shift Scheme To Support Mobile Sink Group In Wireless Sensor Networks, Yongbin Yim, Kyong Hoon Kim, Monther Aldwairi, Ki Il Kim

All Works

© 2017 by the authors. Licensee MDPI, Basel, Switzerland. Mobile sink groups play crucial roles to perform their own missions in many wireless sensor network (WSN) applications. In order to support mobility of such sink groups, it is important to design a mechanism for effective discovery of the group in motion. However, earlier studies obtain group region information by periodic query. For that reason, the mechanism leads to significant signaling overhead due to frequent flooding for the query regardless of the group movement. Furthermore, the mechanism worsens the problem by the flooding in the whole expected area. To deal with …

Absorption Coefficient Dependent Non-Linear Properties Of Thin Film Luminescent Solar Concentrators, S. Chandra, M. Rafiee, John Doran, S. J. Mccormack

Articles

This research article studied absorption coefficient dependent losses and efficiency of thin film luminescent solar concentrator (LSC). The optimum absorption coefficient was determined by fabricating red dye doped thin film LSCs with varying absorption coefficients of 24–202 cm-1. The optical, electrical, and ray-trace model predicted results were compared to establish the optimum absorption coefficient for fabricated thin film LSCs. The optical and electrical efficiencies of thin film LSCs are a function of absorption coefficient; follow linearly at lower values, gradually becoming non- linear at higher values of absorption coefficient which restricts the overall efficiency. The multi layered ray–trace model predicted …

Analysis Of Vibrational Modes Of Chemically Modified Tone Wood, Madison Flesch

Honors Program Theses

It is generally accepted that every violin has different tone quality in terms of intonation and the depth of the harmonics produced. The best violins are made by experienced luthiers that craft each with precision to produce the best possible tonal quality. The quality of the finished violin is dependent upon both the specific shape and the vibrational response of the wood used in its construction. Because the hard wood used in violin construction is inhomogeneous, the composition and structure of material used is critical to the final product.¹ Luthiers would initially rely on their experience to feel the …

Remotely Sensed Hydroclimatic Variability For Water Security In An Agricultural Basin, Ashish Kondal

Graduate Theses, Dissertations, and Problem Reports (ETD)

The Indus Basin has supported agricultural practices since the Harappan civilization (3000-1500 BC). Abundance of water has always supported agriculture in the region and built the Indus Basin as one of the major agriculture based economies of the world. The obvious dependency of agriculture on weather and the vagaries of climate emphasizes the necessity of a comprehensive hydro-climate study of the region. The role of climate change in the Indus Basin has always been a contentious issue. Groundwater depletion is evident in the region, and its steady and alarmingly declining rate has brought concerns for the future of agriculture in …

Effects Of Ag Promotion And Preparation Method On Cobalt Fischer- Tropsch Catalysts Supported On Silica-Modified Alumina, Mahmood Rahmati, Baiyu Huang, Landon M. Schofield, Thomas H. Fletcher, Brian F. Woodfield, William C. Hecker, Calvin H. Bartholomew, Morris D. Argyle

Faculty Publications

A series of silver-promoted, 20 wt% cobalt Fischer-Tropsch synthesis (FTS) catalysts supported on an alumina modified with 5 wt% silica were prepared using two methods: traditional incipient wetness impregnation (IWI) and a new solvent deficient precipitation (SDP) technique. Catalysts containing silver promoter concentrations of 0.3, 0.6, 1.2, and 2.5 wt% were prepared using each of the two methods. Silver improved the reducibility of the cobalt significantly, lowering reduction temperatures by up to 100 C, and increasing the extent of reduction by up to 35%. Further, in both preparation methods, changing the silver loading altered the cobalt dispersion. The smallest Co …

Examining Engineering Design Cognition With Respect To Student Experience And Performance, Greg J. Strimel, Eunhye Kim, Scott R. Bartholomew, Diana V. Cantu

Faculty Publications

This study investigated the design cognition and performance results of secondary and post-secondary engineering students while engaged in an engineering design task. Relationships between prototype performance and design cognition were highlighted to investigate potential links between cognitive processes and success on engineering design problems. Concurrent think-aloud protocols were collected from eight secondary and 12 post-secondary engineering students working individually to design, make, and evaluate a solution prototype to an engineering design task. The collected protocols were segmented and coded using a pre-established coding scheme. The results were then analyzed to compare the two participant groups and determine the relationships between …

Modeling, Designing And Analysis Of A Standalone Pv Dc Microgrid System, Sharaf Sumaiya

College of Graduate Studies: Theses & Dissertations

The increasing concern about global warming, the upsurge of oil prices, and pollution of petroleum energy has led scientists to search for cost-effective energy sources, for example, photovoltaics. Recently DC microgrids have also drawn more consideration because of the expanding use of direct current (DC) energy sources, energy storages and loads in power systems. First, as a groundwork, the 1D organic solar cell has been investigated that leads to design 3D organic solar cell. Then design and analysis of a standalone solar PV system with dc microgrid has been proposed to supply power for both DC and AC loads. The …

Explanatory And Causality Analysis In Software Engineering, Yasser Ali Alshehri

Graduate Theses, Dissertations, and Problem Reports (ETD)

Software fault proneness and software development efforts are two key areas of software engineering. Improving them will significantly reduce the cost and promote good planning and practice in developing and managing software projects. Traditionally, studies of software fault proneness and software development efforts were focused on analysis and prediction, which can help to answer questions like `when’ and `where’. The focus of this dissertation is on explanatory and causality studies that address questions like `why’ and `how’.

First, we applied a case-control study to explain software fault proneness. We found that Bugfixes (Prerelease bugs), Developers, Code Churn, and Age of …

Experimental Design, Testing, And Evaluation Of Methods To Improve The Efficiency And Reduce Emissions From A Small Two-Stroke Natural Gas Engine, Christopher Joseph Ulishney

Graduate Theses, Dissertations, and Problem Reports (ETD)

Decentralized power generation is a research area of interest due to possible improvements in electrical generation efficiency and grid resilience. Two-stroke engines are simple, inexpensive, power dense systems that could serve as the prime-movers for combined heat and power (CHP) systems. In addition, such systems could be fueled on natural gas (NG) that is readily available to serve as a reliable fuel source in most households. However, most two-stroke engines are inefficient and produce excessive emissions. This research focused on methods to simultaneously improve engine efficiency and decrease emissions from a 34 cc air-cooled, two-stroke engine retrofitted to operate on …

Parametric Study Of Coal Liberation Behavior Using Silica Grinding Media, Adewale Wasiu Adeniji

Graduate Theses, Dissertations, and Problem Reports (ETD)

This study evaluates the coal liberation behavior using silica as the grinding media by assessing the effects of four operating factors including nominal feed size, media size, shaft speed and grinding time, each of three levels on two response variables, the product P₈₀ and the specific energy. The coal material used in this study was mixed-phase particles commonly referred to as middlings, sampled from dense medium circuit at the Leatherwood preparation plant in Kentucky. One-third fractional factorial design of resolution III was implemented. Since silica was obtained in three standard size ranges as per manufacturer’s design, media size was …

Ucs And Cbr Behaviour Of Perth Sandy Soil Reinforced With Waste Tyre Fibres And Cement, Seyed M. A. Bazazorde

Theses: Doctorates and Masters

Weak and unsuitable soil conditions have always caused problems for civil engineers during the construction of structures. To avoid problems in a cost-effective manner, proper and reliable solutions need to be developed. Fibre reinforcement and cement stabilisation are the most efficient and common methods in geotechnical engineering applications when engineers have problematic soil conditions. These methods can be used in different applications, such as pavement layers, retaining walls and slopes.

Over the past three decades, many studies have been done to investigate the effects of adding synthetic and natural fibres to soil as the reinforcing material alone or with cement. …

Automated Optical Mark Recognition Scoring System For Multiple-Choice Questions, Murtadha Alomran

Theses: Doctorates and Masters

Multiple-choice questions are one of the questions commonly used in assessments. It is widely used because this type of examination can be an effective and reliable way to examine the level of student’s knowledge. So far, this type of examination can either be marked by hand or with specialised answer sheets and scanning equipment. There are specialised answer sheets and scanning equipment to mark multiple-choice questions automatically. However, these are expensive, specialised and restrictive answer sheets and optical mark recognition scanners.

This research aims to design and implement a multiple-choice answer sheet and a reliable image processing-based scoring system that …

An Integrated System To Design Machine Layouts For Modular Special Purpose Machines, Uday Hameed Farhan

Theses: Doctorates and Masters

This thesis introduces the development of an integrated system for the design of layouts for special purpose machines (SPMs). SPMs are capable of performing several machining operations (such as drilling, milling, and tapping) at the same time. They consist of elements that can be arranged in different layouts. Whilst this is a unique feature that makes SPMs modular, a high level of knowledge and experience is required to rearrange the SPM elements in different configurations, and also to select appropriate SPM elements when product demand changes and new layouts are required. In this research, an integrated system for SPM layout …

Using Agricultural Wastes To Treat Lead-Contaminated Water In Western Australia, Hanie Hashtroudi

Theses: Doctorates and Masters

Aqueous solutions are becoming increasingly contaminated in all parts of the world (2015). Heavy metals are toxic contaminants that are mainly distributed in urban stormwater run-off and industrial wastewaters as a result of some mining operations, electronic assembly planting, battery manufacturing, and etching operations (Kadirvelu et al. 2001). Pb (II) is a heavy metal that causes significant damage in the human body. Drinking lead-contaminated water even at low concentrations may cause lifethreatening conditions such as cancer, kidney damage, brain damage, and liver problems (El-Said 2010). Therefore, it is necessary to remove lead from aqueous solutions.

Several conventional physical, chemical, and …

A Review Of Unsupervised Statistical Learning And Visual Analytics Techniques Applied To Performance Analysis Of Non-Residential Buildings, Clayton Miller, Zoltán Nagy, Arno Schlueter

Research Collection College of Integrative Studies

Measured and simulated data sources from the built environment are increasing rapidly. It is becoming normal to analyze data from hundreds, or even thousands of buildings at once. Mechanistic, manual analysis of such data sets is time-consuming and not realistic using conventional techniques. Thus, a significant body of literature has been generated using unsupervised statistical learning techniques designed to uncover structure and information quickly with fewer input parameters or metadata about the buildings collected. Further, visual analytics techniques are developed as aids in this process for a human analyst to utilize and interpret the results. This paper reviews publications that …

Face Size Biases Emotion Judgment Through Eye Movement, Shuo Wang

Faculty & Staff Scholarship

Faces are the most commonly used stimuli to study emotions. Researchers often manipulate the emotion contents and facial features to study emotion judgment, but rarely manipulate low-level stimulus features such as face sizes. Here, I investigated whether a mere difference in face size would cause differences in emotion judgment. Subjects discriminated emotions in fear-happy morphed faces. When subjects viewed larger faces, they had an increased judgment of fear and showed a higher specificity in emotion judgment, compared to when they viewed smaller faces. Concurrent high-resolution eye tracking further provided mechanistic insights: subjects had more fixations onto the eyes when they …

Deployable Lenticular Stiffeners For Origami-Inspired Mechanisms, Larry L. Howell, Alden D. Yellowstone

Faculty Publications

Light-weight origami-inspired mechanisms can provide advantages in deployable space systems and other applications. However, a significant challenge in their design is ensuring that they are sufficiently stiff. Compliant, deployable stiffeners utilizing a profile approximating the Euler Spiral are proposed as one solution. Structures with this profile, called a lenticular stiffener, are shown to permit stiffeners to flatten using forces applied at their edges. Formulas for calculating the stiffness increase are developed. Relations needed to design the deployment behavior of the stiffeners are also derived. Finally, advantages of different stiffener configurations are evaluated. These results are verified through simulation and experiments.

A Comparison Of Traditional And Adaptive Comparative Judgment Assessment Techniques For Freshmen Engineering Design Projects, Scott R. Bartholomew, Greg J. Strimel, Andrew Jackson

Faculty Publications

This article examines the use of an alternative form of assessment for engineering design projects called adaptive comparative judgment (ACJ). The researchers employed an ACJ tool to evaluate undergraduate engineering student design projects in an effort to examine its’ reliability, validity, and utility in comparison with traditional assessment techniques. The ACJ process employed multiple judges to compare the design artifacts of 16 first-year engineering majors. The authors conducted an analysis of the reliability and validity of the ACJ method compared to the traditional rubric used to evaluate the project and the performance data of each student’s design prototype. For these …

Engineering Standards In Highway Design Litigation, Michael Lewyn

Scholarly Works

Highway engineers sometimes believe that if they redesign streets to improve pedestrian safety (for example, by introducing traffic calming techniques) they might be successfully sued for negligent design by motorists. This chapter suggests that in such situations, governments are likely to be protected by discretionary function immunity. In addition, the chapter discusses a variety of technical issues.

Characterization Of Pyrolysis Products From Fast Pyrolysis Of Live And Dead Vegetation Native To The Southern United States, Mohammad-Saeed Safdari, Mahmood Rahmati, Elham Amini, Joel E. Howarth, Jansen P. Berryhill, Mark Dietenberger, David R. Weise, Thomas H. Fletcher

Faculty Publications

Prescribed burning (controlled burning) is used to decrease accumulation of combustible materials and reduce impact of uncontrolled wildland fires. Prescribed fires are often used to burn undergrowth in Southern forests of the United States. In order to improve prescribed fire application, accomplish desired fire effects, and limit potential runaway fires, an improved understanding of the fundamental processes related to combustion of heterogeneous fuel beds of live and dead fuels is needed. The initial processes of combustion involve pyrolysis and ignition. During this research, fast pyrolysis of 14 live and dead (biomass) plant species which are native to the Southern United …

Formation Of Deposits From Heavy Fuel Oil Ash In An Accelerated Deposition Facility At Temperatures Up To 1219 °C, Robert Laycock, Thomas H. Fletcher

Faculty Publications

Some industrial gas turbines are currently being fired using heavy fuel oil, which contains a small percentage of inorganic material that can lead to fouling and corrosion of turbine components. Deposits of heavy fuel oil ash were created in the Turbine Accelerated Deposition Facility (TADF) at Brigham Young University under gas turbine-related conditions. Ash was produced by burning heavy fuel oil in a downward-fired combustor and collecting the ash from the exhaust stream. This ash was then introduced into the TADF and entrained in a hot gas flow that varied from 1101 °C to 1219 °C. Sulfur dioxide was introduced …