Engineering Commons^™

An Analysis Of Learning Curve Theory & Diminishing Rates Of Learning, Dakotah W. Hogan

Theses and Dissertations

Traditional learning curve theory assumes a constant learning rate regardless of the number of units produced; however, a collection of theoretical and empirical evidence indicates that learning rates decrease as more units are produced in some cases. These diminishing learning rates cause traditional learning curves to underestimate required resources, potentially resulting in cost overruns. A diminishing learning rate model, Boones Learning Curve (2018), was recently developed to model this phenomenon. This research confirmed that Boones Learning Curve is more accurate in modeling observed learning curves using production data of 169 Department of Defense end-items. However, further empirical analysis revealed deficiencies …

Analysis Of Additively Manufactured Rings Under Compression Loading For Use In A Vacuum Lighter Than Air Vehicle Structure, Kevin D. Greenoe

Theses and Dissertations

A Vacuum Lighter Than Air Vehicle (VLTAV) utilizes a lightweight structure paired with an internal vacuum to achieve buoyancy; this allows it to float through-out a given atmosphere. The pressure differential between the internal vacuum andexternal atmosphere places the vehicle under intense loading. A specific structure under investigation is the celestial icosahedron, which features nine intersecting rings that have an outer diameter of 0.2032m and circular cross-sectionalthickness of 5.08mm.The celestials rings are positioned in three different orientations and are analyzed both experimentally and analytically.

Experimental Measurements Of Hypseronic Instabilities Over Ogive-Cylinders At Mach 6, Jonathan Luke Hill

Theses and Dissertations

Hypersonic boundary layer transition experiments were performed in the Air Force Research Lab (AFRL) Mach 6 Ludwieg tube over a meter long ogive-cylinder model with interchangeable nose tip angles and bluntnesses. Measurements of instabilities were captured via focused laser differential interferometry (FLDI), surface mounted pressure sensors, and high speed Schlieren imagery at nominal unit Reynolds numbers ranging from 4.0*10⁶/m to 1.4*10⁷/m. This study attempts to isolate the effects of increasing tip angle and spherical bluntness on instabilities measured downstream over the cylindrical body of the model.

On The Corrosion Behaviour Of As-Cast And Heat-Treated Mg-Re Alloys In 0.9% Nacl Solution, Abdelkader Hanna, Lyacine Rabahi, Mohamed Amine Soualili, Achour Dakhouche, Djamel Bradai, Hiba Azzeddine

Journal of Metals, Materials and Minerals

The microstructure and corrosion behaviour of as-cast and heat-treated Mg-1.44Nd and Mg-1.43Ce (wt.%) alloys in 0.9% NaCl (wt.%) solution were investigated using electrochemical tests, X-ray diffraction (XRD) and scanning electron microscopy, combined with energy-dispersive X-ray spectroscopy (SEM-EDS). The as-cast microstructure of both alloys revealed the presence of second phases. Heat treatment at 535°C for 6 h led to a more uniform distribution of the second phases in Mg-1.44Nd alloy and their dissolution along the grains boundaries in the Mg-1.43Ce alloy. As a result, the corrosion resistance was improved in the heat-treated alloys. Accordingly, the corrosion resistance values for the heat-treated …

Numerical Modeling Of Longwall Top Coal Caving Method At Thar Coalfield, Niaz Muhammad Shahani, Zhijun Wan, Xigui Zheng, Li Guichen, Cancan Liu, Fahad Irfan Siddiqui, Gu Bin

Journal of Metals, Materials and Minerals

Thar Coalfield in Pakistan is the largest reserve of lignite coal in the country, which is outlined by thick coal seams. The preferred mining method for these thick coal seams is the Longwall Top Coal Caving (LTCC). The connection of both the top coal caving and its compactness are still rare; therefore, the capability of top coal caving mechanism is the most significant factor in LTCC that must be adequately explained and examined. Moreover, in order to achieve the ideal coal production, a comprehensive modeling of deformation and induced stress is mandatory. In this study, a 12 m thick coal …

Information Technology News, Georgia Southern University

Information Technology: News & Publications (2012-2023)

• TekLAN48 -- March 6, 2020

A Compendium Of Single Cell Analysis In Aging And Disease, Uday Chintapula, Samir M. Iqbal, Young-Tae Kim

Electrical and Computer Engineering Faculty Publications

Cell is the fundamental structural and functional unit of complex multicellular organisms. Conventional methods which involve average analysis of cells in bulk populations can undermine physiologically significant cell populations, whereas analysis of cells at a single cell level may reveal unique biomarkers and other mechanisms that govern the genotype and phenotype in various physiological processes in presumed homogenous cell populations. Cellular abnormalities such as irregularities in cellular mechanisms have been linked to human aging and other major diseases including neurodegenerative, vascular, autoimmune, and cancer. Aging is a functional decline associated with various diseases in an organism, majorly arising from cellular …

Real-Time Monitoring Of The Semiconductor Wirebond Interconnection Process For Production Yield And Quality Improvement, Reymart Rio C. Haldos, Patricia Angela R. Abu, Carlos M. Oppus, Rosula Sj Reyes

Electronics, Computer, and Communications Engineering Faculty Publications

The electronics industry in the Philippine is the largest contributor to the manufacturing sector within the country. The Philippines is also considered the fastest growing economy in the region where its electronics products are among its top exports. The manufacturing of new electronics devices that comes with the emerging technologies translate to new processes that require new equipment that poses challenges to the industry. Thus, innovative solutions are developed by the engineers to improve and increase the production yield. This study presents the development of a monitoring system that is interfaced to an existing wirebonding machine as a means of …

Evaluation Of Diode Laser Application On Chemical Analysis And Surface Microhardness Of White Spots Enamel Lesions With Two Remineralizing Agents, Lamiaa Mahmoud Moharam, Doaa Mohamed Sadony, Shaymaa Mohamed Nagi

Chemical and Biochemical Engineering Faculty Research & Creative Works

Background: To investigate the effect of diode laser application and two commercial remineralizing agents on the remineralization and surface microhardness of white spot enamel lesions. Material and Methods: Sixty specimens were prepared then equally divided into six groups (n=10/group), according to the diode laser and the two commercial remineralizing agents applied to demineralized enamel surfaces (APF gel and sodium fluoride NaF mousse) with or without diode Laser application as follows; Group A; control, Group B; diode Laser application, Group C; APF gel application, Group D; NaF mousse application, Group E; APF gel application + diode Laser, Group F; NaF mousse …

Laser Shock Peening Pressure Impulse Determination Via Empirical Data-Matching With Optimization Software, Colin C. Engebretsen

Theses and Dissertations

Laser shock peening (LSP) is a form of work hardening by means of laser induced pressure impulse. LSP imparts compressive residual stresses which can improve fatigue life of metallic alloys for structural use. The finite element modeling (FEM) of LSP is typically done by applying an assumed pressure impulse, as useful experimental measurement of this pressure impulse has not been adequately accomplished. This shortfall in the field is a current limitation to the accuracy of FE modeling, and was addressed in the current work. A novel method was tested to determine the pressure impulse shape in time and space by …

The Effect Of Passive And Active Boundary-Layer Fences On Delta Wing Performance At Low Reynolds Number, Anna C. Demoret

Theses and Dissertations

The effect of passive and active boundary-layer fences (BLFs) on performance is evaluated on a NACA 0012 delta wing (c_root = 14in, c_tip = 2.8in, Λ = 45°, b = 23.5in) at a Reynolds number (Re) of 5.0 x 10⁵ based on the root chord. The performance improvements of a passive BLF are replicated and improved upon using an active flow control (AFC) fluidic fence created by a wall-normal steady-blowing jet from a slot. The application of a passive BLF at a spanwise location of 70% z/b resulted in an 8.7% increase in C_Lmax compared to …

Solution Anneal Heat Treatments To Enhance Mechanical Performance Of Additively Manufactured Inconel 718, David J. Newell

Theses and Dissertations

The nickel-based superalloy Inconel 718 (IN718) is an excellent candidate among aerospace alloys for laser powder-bed fusion (LPBF) manufacturing. As-built LPBF IN718 has a vertically aligned columnar (001) microstructure which translates into orthotropic mechanical behavior. The post-process heat treatments for IN718 were developed 60 years ago for wrought and cast processes and do not mitigate the columnar microstructure of the LPBF process. Recrystallization is required to remove the columnar microstructure, which would allow for parts to be fabricated on different machines or in different orientations but still achieve the same properties. This research investigated the microstructure of LPBF IN718 as …

Development Of A Small Scale Rotating Detonation Engine, Joseph R. Dechert

Theses and Dissertations

The Rotating Detonation Engine (RDE) has been researched extensively in recent years, but the minimum size limits of an RDE have not been well investigated. The goal of this research was to build an RDE small enough to produce a detonation frequency above 20 kHz with a single detonation wave while also reducing the engine's mass ow rate. An engine with these design characteristics would reduce hazards associated with previous RDE testing. This research objective resulted in the design of an RDE with an outer diameter sized at 28 mm using ethylene and nitrous oxide as a fuel and oxidizer. …

Effects Of High Freestream Turbulence And Conduction On Film Cooling Effectiveness Of Shaped Holes, Richard A. Macias Jr.

Theses and Dissertations

With technological advancements allowing higher turbine temperatures, film cooling continues to be an important research area. The Film Cooling Rig (FCR) was fitted with a turbulence generator to vary freestream turbulence intensity and length scale, enabling the effects of high freestream turbulence on overall effectiveness to be studied. A cylindrical hole and laidback fan-shaped hole were investigated over a range of Advective Capacity Ratio (ACR) for freestream turbulence intensities of 2%, 10%, and 15%. For a given ACR, increasing the turbulence intensity resulted in lower overall effectiveness values due to the larger heat transfer coefficient that comes from turbulent ow. …

Detonation Confinement In A Radial Rotating Detonation Engine, Kavi Muraleetharan

Theses and Dissertations

Radial Rotating Detonation Engines (RRDE) have provided an opportunity for use of a pressure-gain combustor in a more compact form compared to an axial RDE. A successfully tested RRDE has operated over a wide range of test conditions and produced detonation modes with one, two, and three waves. The presence of multiple waves located the detonation waves to the outer radius, while one wave modes operated closer to the inner radius. Locating the detonation wave closer to the inner diameter resulted in less time for combustion prior to the radial turbine. Subsequently, this tended to decrease efficiency. To attempt to …

Space-Based Localization Of Radio Frequency Transmitters Utilizing Macaulay Resultant And Heuristic Optimization Methods, Jessica M. Wightman

Theses and Dissertations

This research focuses on radio frequency geolocation of space objects utilizing space-based platforms. Geolocation has long been the solution for locating objects. In particular, this study examines the scenario of two cooperative receivers geolocating a transmitter in close proximity. An algorithm is developed to calculate the initial estimated transmitter location and projected orbital trajectory. The algorithm uses the Macaulay method of solving a system of polynomials as well as heuristic optimization techniques to locate a transmitter with respect to receivers at different time intervals. For the scenarios investigated, both Macaulay and heuristic optimization methods achieve initial relative orbit determination.

Spacecraft Position Estimation And Attitude Determination Using Terrestrial Illumination Matching, Liberty M. Shockley

Theses and Dissertations

An algorithm to conduct spacecraft position estimation and attitude determination via terrestrial illumination matching (TIM) is presented consisting of a novel method that uses terrestrial lights as a surrogate for star fields. Although star sensors represent a highly accurate means of attitude determination with considerable spaceflight heritage, with Global Positioning System (GPS) providing position, TIM provides a potentially viable alternative in the event of star sensor or GPS malfunction or performance degradation. The research defines a catalog of terrestrial light constellations, which are then implemented within the TIM algorithm for position acquisition of a generic spacecraft bus. With the algorithm …

Moment Redistribution In Continuous Rc Beams Top Strengthened With Steel And Cfrp Plates, Amr Ibrahim, Ayman Khalil, Shady Salem, Mahmoud El-Kateb

Civil Engineering

It is common practice to retrofit continuous reinforced concrete (RC) beams by fiber reinforced polymer (FRP) or steel plates. This can cause a significant amount of moment redistribution (MR) which results in an efficient and economic design when taken into consideration. There is lack in research regarding MR in continuous RC beams when strengthening plates are applied only at the top side at the hogging regions. The main purpose of this paper is to assess MR in continuous RC beams top strengthened with steel and/or carbon fiber reinforced polymer (CFRP) plates. In this respect, a nonlinear finite element model was …

Using Knowledge Bases For Question Answering, Yunshi Lan

Dissertations and Theses Collection (Open Access)

A knowledge base (KB) is a well-structured database, which contains many of entities and their relations. With the fast development of large-scale knowledge bases such as Freebase, DBpedia and YAGO, knowledge bases have become an important resource, which can serve many applications, such as dialogue system, textual entailment, question answering and so on. These applications play significant roles in real-world industry.

In this dissertation, we try to explore the entailment information and more general entity-relation information from the KBs. Recognizing textual entailment (RTE) is a task to infer the entailment relations between sentences. We need to decide whether a hypothesis …

Predicting The Prevalence Of Autonomous Heavy Equipment In The Construction Industry, Mitchell T. Bongi

Construction Management

Autonomy is a topic that is gaining speed throughout the world as labor shortages rise, wages increase the desire for greater safety in dangerous fields accelerates. One industry that has had a slower start but looks to join the autonomous bandwagon is construction. Different experts in different fields from engineers to construction managers give different timelines as to when this autonomous technology will be normally present in certain construction industries, however an accurate timeline has yet to be determined. The objective of this paper is to provide a more accurate timeline as to when autonomous heavy equipment will be prevalent …

Crime And Harassment On Public Transportation: A Survey Of Sjsu Students Set In International Context, Asha Weinstein Agrawal, Anastasia Loukaitou-Sideris, Cristina Tortora, Yajing Hu

Mineta Transportation Institute

Communities around the world are gradually becoming aware that transit riders, and especially women, are often victims of a wide range of offenses of a sexual nature that happen on buses and trains, and at bus stops and train stations. Better understanding the extent and nature of sexual harassment on transit is a critical issue for transit operators and society at large. If fear of sexual crime limits if and how people ride transit, the result is reduced mobility for certain segments of the population, as well as lost ridership for transit agencies.

For this study, we surveyed 891 students …

Developing A Computer Vision-Based Decision Support System For Intersection Safety Monitoring And Assessment Of Vulnerable Road Users, Arash Jahangiri, Anagha Katthe, Aryan Sohrabi, Xiaobai Liu, Shashank Pulagam, Vahid Balali, Sahar Ghanipoor Machiani

Mineta Transportation Institute

Vision-based trajectory analysis of road users enables identification of near-crash situations and proactive safety monitoring. The two most widely used sur-rogate safety measures (SSMs), time-to-collision (TTC) and post-encroachment time (PET)—and a recent variant form of TTC, relative time-to-collision (RTTC)—were investigated using real-world video data collected at ten signalized intersections in the city of San Diego, California. The performance of these SSMs was compared for the purpose of evaluating pedestrian and bicyclist safety. Prediction of potential trajectory intersection points was performed to calculate TTC for every interacting object, and the average of TTC for every two objects in critical situations was …

Development Of A Quality Control Method And Guidelines For Hot Mix Asphalt Using Recycled Concrete Aggregate, Xiaojun Li, Dingxin Cheng, Kun Zhang, Kanwar M. S. Jakhar, Uday V. Pericherla

Mineta Transportation Institute

Each year, about 122 million tons of aggregates, a major structural component of pavement, are used in asphaltic mixtures in pavement construction. At the same time, aging U.S. infrastructure produces around 200 million tons of demolition waste each year, half of which is concrete debris. Therefore, introducing recycled concrete aggregate (RCA) as hot mix asphalt (HMA) aggregate could not only relieve the disposal pressure but also result in considerable reductions in cost, energy usage, and greenhouse gas emissions in the paving industry. A limited number of studies regarding the use of RCA to substitute virgin aggregate in HMA (RCA-HMA) exist. …

Infrared-Active Phonon Modes In Single-Crystal Thorium Dioxide And Uranium Dioxide, Sean Knight, Rafal Korlacki, Christina Dugan, James C. Petrosky, Alyssa Lynn Mock, Peter A. Dowben, J. Matthew Mann, Martin M. Kimani, Mathias Schubert

Department of Electrical and Computer Engineering: Faculty Publications

The infrared-active phonon modes, in single-crystal samples of thorium dioxide (ThO₂) and uranium dioxide (UO₂), were investigated using spectroscopic ellipsometry and compared with density functional theory. Both ThO₂ and UO₂ are found to have one infrared-active phonon mode pair [consisting of one transverse optic (TO) and one associated longitudinal optic (LO) mode], which is responsible for the dominant features in the ellipsometric data. At room temperature, our results for the mode pair’s resonant frequencies and broadening parameters are comparable with previous reflectance spectroscopy characterizations and density functional theory predictions. For ThO₂, our …

Housing And Community Development Project In Siem Reap, Cambodia, Gerald F. Charette Iii

Construction Management

Habitat for Humanity Global Village is an international organization that gathers materials and volunteers to build homes for less fortunate villages in more than 70 different countries. The team I applied for was chosen to build a house for a family of four in a village near Siem Reap, Cambodia. I chose this as my senior project because it combines my interests in construction and humanitarian work, as well as giving me the opportunity to expand my knowledge of a different country’s construction means and methods. I felt that that the best way to showcase the material that I have …

Construction Curriculum Developed For Continuation Schools, Orlando I. Yepez

Construction Management

This paper will discuss a curriculum, an introduction to construction fundamentals, that was built for continuation schools. A continuation school is a school for at-risk youth in which it provides programs of empowering, inspiration and outlet. Five modules were created that focus on different sections of the construction industry. These modules consist of Site Safety, Untroduction to Basic Math, Introduction to Power Tools, Introduction to Construction Drawings, and Basic Employable Skills. Each module will consist of a ten-question quiz and presentation. Two homework assignments were also created. One homework assignment for site safety which requires students to identify if the …

Understanding Transport Of An Elastic, Spherical Particle Through A Confining Channel, Shuaijun Li, Honghui Yu, Tai-De Li, Zi Chen, Wen Deng, Alimohammad Anbari, Jing Fan

Civil, Architectural and Environmental Engineering Faculty Research & Creative Works

The transport of soft particles through narrow channels or pores is ubiquitous in biological systems and industrial processes. On many occasions, the particles deform and temporarily block the channel, inducing a built-up pressure. This pressure buildup often has a profound effect on the behavior of the respective system; yet, it is difficult to be characterized. In this work, we establish a quantitative correlation between the built-up pressure and the material and geometry properties through experiments and mechanics analysis. We fabricate microgels with a controlled diameter and elastic modulus by microfluidics. We then force them to individually pass through a constrictive …

Analysis Of Crashes Involving First Responder Vehicles, Josie Gray

Doctoral Dissertations and Master's Theses

First responders face many hazards that put their lives at risk while on duty. A review of the National Law Enforcement Officers Memorial Fund statistics shows that 553 police officers died in the line-of-duty between 2008 and 2017 as a direct result of a traffic related incidents. Sadly, the nation’s first responders are exposed to factors which make them uniquely vulnerable to traffic related injuries and deaths. The goal of this research is to investigate and analyze crashes involving first responder vehicles and struck-by crashes. This project concludes that approximately 1.2% of the crashes in the state of Florida involve …

Theoretical And Computational Analyses On Transition And Turbulence In Purely Oscillating Pipe Flow, Ali Ahmed Abdulrasool

Doctoral Dissertations and Master's Theses

The hydrodynamic instability of purely oscillating pipe flows is investigated in terms of the quasi-steady formulation assuming the temporal changes of the laminar base flow relative to disturbances are slow. A simple model equation is introduced to compare the exact solution of the current approach with those of the major theories dedicated for unsteady flows. The results of the analysis show that the quasi-steady assumption and the multiple scales method are more efficient and accurate than the formal Floquet theory in predicting the transient instabilities within a period in addition to the long-term growth or decay of disturbances. The most …

Corrosion-Induced Mass Loss Measurement Under Strain Conditions Through Gr/Agnw-Based, Fe-C Coated Lpfg Sensors, Chuanrui Guo, Liang Fan, Genda Chen

Civil, Architectural and Environmental Engineering Faculty Research & Creative Works

In this study, graphene/silver nanowire (Gr/AgNW)-based, Fe-C coated long period fiber gratings (LPFG) sensors were tested up to 72 hours in 3.5 w.t% NaCl solution for corrosion-induced mass loss measurement under four strain levels: 0, 500, 1000 and 1500 µ∈. The crack and interfacial bonding behaviors of laminate Fe-C and Gr/AgNW layer structures were characterized using Scanning Electron Microscopy (SEM) and electrical resistance measurement. Both optical transmission spectra and electrical impedance spectroscopy (EIS) data were simultaneously measured from each sensor. Under increasing strains, transverse cracks appeared first and were followed by longitudinal cracks on the laminate layer structures. The spacing …