Browsing by Subject "Engineering"

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A method for developing the true stress-strain relationship for structural steels based on tension coupon tests
(2019-12-02) Jones, Cliff Andrew; Engelhardt, Michael D.; Williamson, Eric B., 1968-; Helwig, Todd; Clayton, Patricia; Taleff, Eric
Predicting the uniaxial stress-stress response of ductile metals like structural steel can provide valuable insight into a broad range of engineering problems. Despite a wide body of research covering more than a century, the approach and guidance related to developing the true stress-strain relationship for ductile metals—specifically structural steels—continues to change and evolve. In particular, guidance related to accurate prediction of the onset of necking and post-necking response remains a topic of ongoing research and capturing these effects remains a challenge to researchers and engineers. The research presented in this dissertation was undertaken to extend the body of knowledge in this area. Particular emphasis is placed on developing a true stress-strain relationship for structural steels that is capable of capturing the onset of necking and post-necking behavior up to fracture. In addition, as standard tension coupon load-deformation data are often the only available information from which to develop such a model, the processes and guidance presented in this dissertation require only that input information. Therefore, advanced experimental approaches and measurement techniques are not required to leverage the guidance presented herein. This path was chosen in the hopes of providing guidance that would be broadly applicable to a wide range of problems, industries, research, and practicing professionals. This dissertation proposes a method for developing a true stress-strain relationship for structural steels that can be directly used in predictive finite element analysis (FEA) models using three-dimensional (3D) solid elements. The result of this research indicate that such a model should be able to reproduce the experimental results of the tension test quite accurately, providing validation and verification of the assumed material definition. Additionally, three derivative rules are presented. These rules were distilled from existing research and provide simple guidelines for capturing necking, maintaining computational stability and uniqueness, and prohibiting post-necking cold-drawing behavior. The rules are incorporated into the recommended process for developing the true stress-strain relationship for structural steels; however, they are also presented separately so they can easily be incorporated into alternate methods for defining such a constitutive relationship. Finally, while this research has furthered the understanding of the true stress-strain relationship of structural steels, particularly in predicting necking and post-necking behavior, there is still considerable room for additional research on this topic. For example, automation, incorporating error minimizing techniques, and adding local and material-level and microstructural phenomena (e.g., void formation, growth and coalescence) each offer great potential for extending and improving the recommendations presented in this dissertation. Thus, while this effort has intentionally maintained a limited focus, it is the authors hope that it serves others as one more small step toward accurate prediction of the load-deformation behavior of structural steels and other ductile metals.
A quantitative study of intended post-graduation plans of undergraduate biomedical engineering students : assessing self-efficacy, value, and identity beliefs
(2020-04-09) Patrick, Anita D.; Riegle-Crumb, Catherine; Borrego, Maura; Markey, Mia; Neff, Kristin
There has been a consistent call to action to attract talented individuals to help bolster the STEM workforce. Yet, the lack of diversity of students attracted to STEM and the inability to retain them in the profession persists. Among STEM fields, engineering is a prime discipline for examining this challenge. However, treating engineering as one monolithic profession is both inaccurate and misleading as there are over 28 accredited engineering programs in the United States alone with varying levels of diversity based on student demographics. Nonetheless, engineering programs remain male-dominated; however, biomedical engineering (BME) is one such discipline with nearly equal proportions of men and women. BME is a unique case in which to study the intended post-graduation plans of undergraduate engineering students as degree holders have been cited to go on to work in a variety of careers in and outside of the engineering workforce. My aim in this dissertation is to address gaps in the biomedical engineering/engineering education literature on undergraduate women’s intended career choices and related implications. In doing so I problematize the binary and often deficit view of “stay or leave” as related to persistence in engineering and instead further contextualize choice by capturing the potentialities of students’ intended post-graduation plans. Drawing from Eccles’ Expectancy Value Theory and models of STEM Identity in engineering education, I investigate this issue. Using quantitative research methodologies, I explore the structural relationships between student gender and the motivational engineering attitudes of academic self-efficacy, interest, utility value, attainment value, and professional identity. Data was gathered from n=716 undergraduate biomedical engineering students from a large public research institution in the Southwestern United States. Using hierarchical agglomerative cluster analysis, the results revealed students form five clusters of intended post-graduation plans: Engineering, Job, Non-engineering, All, and School. I further examined the composition of these clusters by student gender and classification; gender differences in engineering attitudes between clusters; and gender differences in engineering attitudes within clusters followed by structural equation models to assess the fit of gender and engineering attitudes as related to cluster membership. Implications and areas of future research are discussed.
Advanced technology innovation mapping tool to support technology commercialization
(2013-12) Felkl, Jakub, 1982-; Nichols, Steven Parks, 1950-
This work outlines an Innovation Gap in technology commercialization and presents a novel tool, the Advanced Technology Innovation Mapping (ATIM) tool to address this gap. The tool aims to support technology commercialization in early stages of & prior to the New Product Development Process. The dissertation includes a detailed rationale, description, history, similar and originating methods for this tool based on Value Engineering and Function Maps for Design. This work also demonstrates on several example studies the use of the tool and evaluates via an exploratory study the usefulness of the tool. Research tests the tool in educational and training programs at the University of Texas at Austin and finds that the tool improves user understating of majority of important factors for technology commercialization (customer, technology, development activities). User feedback supports these conclusions. In the future the tool could be further expanded, more standardized and improved. Additionally, the work proposes further ways to study the tool in different settings and with groups of different sizes beyond this early exploratory study.
An evaluation and redesign of a vision-based feedback controls experiment for undergraduate dynamic systems and controls laboratory
(2017-05) Campbell, Etse-Oghena Y.; Longoria, Raul G.; Li, Wei
Control systems instructional modules are more commonly developed for control systems engineering students, who are prepared to confront the complexity and large number of topics and concepts required in control systems study. In a general systems and dynamics course, it can be challenging to develop laboratory modules that will be suitable to, say, a general mechanical engineering student audience. This report describes and analyzes a pedagogical tool – a Vision-Based feedback control experiment – to investigate its effectiveness at demonstrating basic feedback control concepts to such a general purpose mechanical engineering undergraduate student audience. The effectiveness of this tool is examined by analyzing student responses to specific queries, designed to test understanding of a topic area or concept. This report evaluates the experimental apparatus pedagogical practice to give the instructor information required for an update on aforementioned practices, to better suit the target student audience, and to ultimately achieve desired module learning outcomes and objectives. The evaluation tools and methods are described in detail, and results show that the Vision-Based Feedback Control Experimental apparatus successfully demonstrates feedback control concepts to the desired student audience, and highlights areas where teaching practice may be improved to improve student comprehension of the concepts and topics presented in the module. The tools and methods presented in this report can be implemented for constantly monitoring the effect of changes and improvements, and are recommended for application to any of the other instructional lab modules in this type of course.
An analysis of the prescribed and enacted curriculum of an engineering unit on helmet design
(2011-08) Gustafson, Katherine Alessandra; Petrosino, Anthony J. (Anthony Joseph), 1961-; Allen, David
Using grounded theory, action research and ethnographic case study methodology this research explores the contrasting ways in which a prescribed curriculum is translated into an enacted curriculum. The current study looks at a 12 week secondary engineering unit (helmet design) which was designed with significant input from a university based team including content experts, learning scientists, master teachers, classroom teachers and school district administrators as part of a grant focused on the creation of a high school engineering course. The unit was enacted in a rural/suburban school by a group of average students by a teacher with high content knowledge in engineering. Five thrusts were identified for analysis including Assessment, Activities, Apparatus, Technology and Standards. Findings indicate much alignment with Apparatus, Standards and Technology thrusts and disparity within the Assessment and Activities thrusts.
Annual Report of the President and Faculties of the University of Texas to the Board of Regents for the Session of 1901-1902
(University of Texas at Austin, 1902) University of Texas at Austin
Application of dynamic optimization methods for foam floods in stratified reservoirs
(2018-08-17) Tang, Brandon Chok-Yie; Nguyen, Quoc P.
Efficient recovery of oil from heavily stratified carbonate reservoirs can be very technically challenging, even when applying waterflood, gasflood, or WAG (water-alternating gas) processes. To date, relatively few field or pilot applications of foam flooding have been conducted due to an incomplete understanding of how foam will behave in the field. The reservoir of interest studied in this work is oil-wet and consists of a stratified upper high-permeability zone overlaying a lower low-permeability zone. This study seeks to assess the performance of the foam flooding process in oil recovery and develop an optimum field injection strategy based upon various objective functions. In the process, the impact of initial waterflooding and varying foam strength on the optimum project termination time, as well as the sensitivity of foam parameters on the optimum field injection strategy is investigated. Two main optimization techniques are tested: static optimization, where the injection parameters are set once at the beginning of the simulation, and dynamic optimization, where injection parameters are optimized in five-year intervals over the life of the well. The dynamic optimization was performed in two ways: a local dynamic optimization and an early-time weighted optimization. In general, the dynamic optimization outperformed the static optimization with respect to all objective functions. Over the course of the study, a variety of objective functions were utilized. The objective functions began with maximizing cumulative oil recovery and evolved to maximizing oil recovery while minimizing gas utilization ratio, and finally maximizing net present value (NPV). From the results, it was ultimately shown that the global dynamic optimization of NPV was the most useful way of obtaining a field injection strategy. The optimal process design parameters indicated that high volumes of surfactant as well as gas in the lower zone needed to be injected early in the life of the project to best maximize NPV. From the optimal termination time study, it was found that the optimal termination time for the project was around ten years. Varying extents of initial waterflooding and alteration of foam strength did not have an impact on the suggested termination time. From the foam strength sensitivity, it was found that among the factors (water saturation, oil saturation, surfactant concentration) considered, the maximum dry-out water saturation had the most profound impact on the NPV. Ultimately, this work develops the framework necessary to create a field injection strategy for foam flooding in the stratified oil-wet reservoir used in this study, but can be extended to other types of reservoirs.
The application of systems engineering to a Space-based Solar Power Technology Demonstration Mission
(2012-05) Chemouni Bach, Julien; Fowler, Wallace T.; Guerra, Lisa A.
This thesis presents an end-to-end example of systems engineering through the development of a Space-based Solar Power Satellite (SSPS) technology demonstration mission. As part of a higher education effort by NASA to promote systems engineering in the undergraduate classroom, the purpose of this thesis is to provide an educational resource for faculty and students. NASA systems engineering processes are tailored and applied to the development of a conceptual mission in order to demonstrate the role of systems engineering in the definition of an aerospace mission. The motivation for choosing the SSPS concept is two fold. First, as a renewable energy concept, space-based solar power is a relevant topic in today's world. Second, previous SSPS studies have been largely focused on developing full-scale concepts and lack a formalized systems engineering approach. The development of an SSPS technology demonstration mission allows for an emphasis on determining mission, and overall concept, feasibility in terms of technical needs and risks. These are assessed through a formalized systems engineering approach that is defined as an early concept or feasibility study, typical of Pre-Phase A activities. An architecture is developed from a mission scope, involving the following trade studies: power beam type, power beam frequency, transmitter type, solar array, and satellite orbit. Then, a system hierarchy, interfaces, and requirements are constructed, and cost and risk analysis are performed. The results indicate that the SSPS concept is still technologically immature and further concept studies and analyses are required before it can be implemented even at the technology demonstration level. This effort should be largely focused on raising the technological maturity of some key systems, including structure, deployment mechanisms, power management and distribution, and thermal systems. These results, and the process of reaching them, thus demonstrate the importance and value of systems engineering in determining mission feasibility early on in the project lifecycle.
Arch bridges
(Bridge Division, Office of Engineering, Federal Highway Administration, U.S. Dept. of Transportation, 1977) Nettleton, Douglas A.
Bridging disciplines : a case study of interdisciplinary design-based learning between undergraduate artists and engineers
(2020-05-06) Harron, Jason Robert; Hughes, Joan E.; Resta, Paul; Azevedo, Flávio S; Klein, Joseph; Vakil, Sepehr
This dissertation’s original contribution to knowledge is a cultural-historical examination of an authentic interdisciplinary partnership at the intersection of the arts and engineering. This observational case study focuses on how creativity activity and interdisciplinary learning emerged as part of a College of Fine Arts course. Course participants included 23 undergraduate fine arts, communication, and engineering majors and their two instructors. This observational case study followed these participants for 14 weeks as they collaborated to design, build, film, and edit practical movie special effects. Within the cultural-historical context of this course, it was the practitioners who made interdisciplinary learning possible. This study found that creativity activity (i.e., those activities that result in new motives, goals, and operations) emerged through artistic constraints as metaconditions. Weekly routines enabled creative activity along with the use of shared spaces and consistent communication protocols. Routines inhibited creative activity when they blocked access, led to scheduling conflicts, and caused delays. The instructors established the pedagogical structure of the course, which provided students with enough scaffolding for creative activity to thrive. Interdisciplinary learning took place when a knowledgeable peer would step back to allow a learner to step up to a task. These steps are part of The Six Steps of Interdisciplinary Learning, which are outlined in this dissertation as a distributed pedagogical content knowledge (PCK) learning model. This interdisciplinary collaboration between artists and engineers influenced perceptions about each other’s disciplines. These findings include that engineers working in an arts-based context were able to put theory into practice in a way that is “not supposed to be perfect.” This interdisciplinary collaboration allowed engineers and fine art majors to gain an appreciation for each other’s knowledge, skills, and abilities. However, some tensions did arise between artists and engineers that led to gatekeeping and resentment. Despite this resentment, the rallying point of the study became the universal respect that emerged when engineers began painting. Findings also include the elicitation of peer and instructor feedback via Slack. Discussion includes suggestions for researcher-practitioner partnerships and a reflection about the current state of science, technology, engineering, arts, and mathematics (STEAM) in higher education.
Calculation of heat processes in welding
(1960) Rykalin, N.N.
Characterizing argumentation structure within the asynchronous, online communication of novice engineering design students
(2014-12) McKenna, William F., active 21st century; Treisman, Uri
Practicing argumentation in secondary school classrooms benefits students both in terms of learning how to argue and learning the course material at hand. Amidst the onset and growth of engineering design courses in secondary schools, this dissertation is an exploratory case study to characterize the use of argumentation among novice student engineering designers. The setting is a high school robotics class. Specifically, a group of students from one class section teamed up with a group of students from a separate class section to design and build a single robot. The team members communicated online via a shared, editable document. That text is the primary data set for my analysis. I looked for indications of argumentation structure that emerged from the online discussion, given that, to my knowledge, the students had not been taught argumentation strategies, per se. Engineering design is relatively new to secondary school, so I thought it appropriate to develop a baseline—a case study that reveals how students communicate about their designs when left largely to their own devices. This study may inform the development argumentation scaffolds that support the students’ existing strengths while ameliorating their weaknesses. My analytical supposition was that argumentation in design will take the form of resolving differences of opinion toward the creation of a single design. Hence, I used Pragma-dialectic theory as my analytical framework. It is a broad theory, based upon resolving differences of opinion in everyday conversation. As such, Pragma-dialectic theory may also be able to encompass the idiosyncrasies of team design, such as reliance on intuition and experience, as well as the important roles that designed objects play throughout the process. Taken together, the importance of intuition, experience, and objects suggests multiple modes of communication that ought to be considered arguments within design deliberations. Results suggest that the students worked to resolve differences of design opinions. In doing so, the students relied heavily on their designed objects to make their arguments meaningful. I classified five object-based claims which emerged from the students’ discussions: keystone, tinkering, visual, tactile, and counterfactual. These form the beginnings of a theory of object-based argumentation.
Convection in a rotating laterally-heated annulus
(Journal of Fluid Mechanics, 1972) Koschmieder, E. L.
Design of an engineering experiment and data driven design in secondary education
(2013-08) Fallin, Patrick Timothy; Allen, David T.
Pre-tests and post tests were used to assess the effectiveness of an engineering high school unit on experimental design and data driven design. The engineering data acquisition unit examined in this report used project based learning to teach the design of an engineering experiment and data driven design as part of the engineering design process. The project consists of the design of a building that can safely withstand an earthquake. Students construct, test and collect data on baseline buildings, with and without load using a shaker table and data acquisition. Students' then design experiments to evaluate design modifications that will meet the customer's needs. Overall, although the number of participants was limited, the survey instruments indicated that understanding of experimental design improved among high school students participating in the unit. Based on this pilot implementation of survey instruments, some of the survey questions were clarified.
Development and evaluation of a mass conservation lab module in a microfluidics environment
(2013-08) King, Andrew Christian; Hidrovo, Carlos; Seepersad, Carolyn
This thesis presents a mass conservation laboratory module developed for use in the undergraduate mechanical engineering curriculum. The module investigates mass conservation fundamentals in a simple T-junction microfluidic device and exposes students to the rapidly developing fields of microfluidics and optical diagnostics. The module is a novel application of microfluidics-based instruction, is highly repeatable, and can be conducted at relatively low cost. A benchmark study was also conducted to evaluate the laboratory module’s efficacy as a teaching tool. This was accomplished through utilizing knowledge assessments before and after student exposure to the laboratory module.
Effects of solar heating and insulation on model biodigester temperature
(2022-07-29) Leigh, Rush; Ellzey, Janet L.; Mullett, John
Biodigesters are important tools for the faecal sludge management in developing countries and in emergency situations such as refugee camps. The effectiveness of biodigesters, however, is limited by local circumstances such as infrastructure issues, skilled labor shortages, and most importantly for this project: lack of temperature control of the biodigester. This thesis delves into the state of the art of biodigesters deployed in emergency situations, identifies many of the specific problems with biodigester effectiveness, and focuses on the importance of regulating the temperature of the biodigester. The primary question addressed by the research is: Can insulation and heating provided by photovoltaic panels (PV) effectively maintain a biodigester (of differing sizes and environmental conditions) within the temperature range for mesophilic digestion (35℃ to 37℃)? Starting with physical experimentation, data was collected from small scale mock biodigesters, under different conditions (e.g., covered by a tarp vs. uncovered, insulation vs. no insulation). Using heat transfer equations, a computational model was developed and compared to experimental data, in order to validate the model. The model results showed good agreement with the experimental measurements in all cases studied. For all experiments, the average difference between the model and actual data was less than 1°C, with the exception of one experiment (Heated vs. Heated Model), which had an average difference of less than 2°C. Using the validated model, four predictive cases were created: (1) Flexigester in coastal climate; (2) Flexigester in seasonal climate; (3) Anaerobic Lagoon in coastal climate; (4) Anaerobic Lagoon in seasonal climate. The scale of the flexigester is approximately 30 m³, and the Anaerobic Lagoon is 1,400 m³. These cases revealed the necessary amount of insulation and number of solar panels necessary to maintain the temperature within the desired range. Although exacts costs are not possible to obtain from these simulations, the results can still be used to determine the cost of the specified amount on insulation and number of solar panels. The estimated costs for retrofitting the four biodigester cases with insulation and solar panels to achieve optimal temperature ranges for mesophilic digestion are as follows: (1) $825, (2) $1,875, (3) $33,750, (4) $78,750. In summary, insulation in combination with heating provided by PV is a promising approach for maintaining biodigesters at optimal temperatures.
Engaging elementary students in active learning through engineering : methods, observations and outcomes
(2014-08) Pearce, Logan Anthony; Petrosino, Anthony J. (Anthony Joseph), 1961-; Barufaldi, James
Engineering as a pedagogical tool for teaching content and driving student intellectual development is often confined to secondary school grades – middle and high school students. The goal of this work is to explore the feasibility of incorporating engineering, in the form of engineering design challenges, into elementary grade levels. The hypothesis is that engineering design challenges can be made to be age appropriate for elementary students, specifically 1st grade students, without sacrificing elements which make them effective pedagogical tools. This hypothesis was tested through the designing of an engineering design challenge for 1st grade students, which was then taught to a group of elementary students, whose responses were analyzed for desired outcomes indicating effectiveness. The design challenge was demonstrated to be engaging, effective, and feasible for the group of elementary students participating in the research. Students were observed to display engineering habits of mind, an understanding of cause and effect, systems thinking, and a basic understanding of science content through participation in the design challenge. Aspects of the design challenge which were not effective or age appropriate are discussed in this work, and recommendations for further modification of the design challenge to better accommodate elementary students is given.
Engineering in a crisis : observing students’ perceived roles of engineers during pandemics and natural disasters
(2021-12-09) LaPatin, Michaela; Faust, Kasey M.; Leite, Fernanda
Engineers have a responsibility to use their skills to protect the welfare of communities. When these ethical responsibilities are discussed in classrooms, the focus is usually on microethics, which focuses on individual decision-making, rather than macroethics that address broad societal concerns. The COVID-19 pandemic has presented a unique opportunity to assess macroethics attitudes because unjust social, economic, and environmental systems have been brought to the forefront amidst the response (e.g., inequitable healthcare systems). In this paper, we consider the COVID-19 pandemic and natural disasters through the lens of engineering macroethics. We aim to understand students’ macroethics attitudes and perceptions about the responsibilities of engineers. In Fall 2020, we deployed a survey to undergraduate engineering students at two universities (n = 520). We asked students to discuss what they perceived to be the role of the engineering profession in response to the global COVID-19 pandemic and natural disasters. We used qualitative content analyses to explore responses in which macroethics attitudes are present and to evaluate the actions that students believe engineers should take in the wake of a crisis. Many of these responses include considerations of infrastructure resilience, resource distribution, and community equity. Logit models were then used to assess the presence of macroethics attitudes in relation to sociodemographic factors of respondents, revealing that factors, including family size, major, and gender influenced these attitudes. Implications from this study include recommendations on curricular content and identifying which student demographic groups would benefit most from intentional macroethical content in coursework.
Evaluation of open-source intrusion detection systems for IPv6 vulnerabilities in realistic test network
(2017-05-03) Gin, Jeremy; Evans, Brian L. (Brian Lawrence), 1965-; Bard, William C
The Internet Protocol (IP) defines the format by which packets are relayed throughout and across networks. A majority of the Internet today uses Internet Protocol version 4 (IPv4), but due to several key industries, a growing share of the Internet is adopting IPv4’s successor, Internet Protocol version 6 (IPv6) for its promise of unique addressability, automatic configuration features, built-in security, and more. Since the invention of the Internet, network security has proven a leading and worthwhile concern. The evolution of the information security field has produced an important solution for network security monitoring: the intrusion detection system (IDS). In this report, I explore the difference in detection effectiveness and resource usage of two network monitoring philosophies, signature-based and behavior-based detection. I test these philosophies, represented by leading edge passive monitors Snort and Bro, against several categories of state-of-the-art IPv6 attacks. I model an IPv6 host-to-host intrusion across the Internet in a virtual test network by including benign background traffic and mimicking adverse network conditions. My results suggest that neither IDS philosophy is superior in all categories and a hybrid of the two, leveraging each’s strengths, would best secure a network against leading IPv6 vulnerabilities.
Exploring the Future Niches of Organic Solar Cells
(2024-05-26) Borrego González, Eric
Organic Solar Cells represent a unique emergent form of photovoltaic power generation technology. Being still in a comparably more nascent phase organic solar cells have unique properties that may be desirable in certain use cases. While the question of organic solar cells being used as an alternative to industry conventional solar cells for power harvesting remains a large question to be answered, this thesis seeks to explore the niches which organic solar cells could be ideal for filling on account of their practicality, and the impact they could make that way. In particular I explore the applications of organic solar cells in solar greenhouses, built into wearables and used in building integration. In all these cases, the thesis examines the efficiency, functional and aesthetic benefits organic solar cells can provide, and uses them as examples of the impact organic solar cell development could have.