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Modeling Reverberant Chambers Used in Time-Reversal Cavities Using Time-Frequency Methods
Get PDFThe signal processing technique of time-reversal is used for various purposes in electro-magnetic interference testing, radar, communication, sonar, and medicine. This paper models the impulse response of a reverberant chamber such as might be used for a time-reversal cavity (TRC) using time-frequency methods. Reverberant chambers have chaotic delaying phase responses that cause the majority of the distortion seen in their impulse response. Time-reversal cancels this, creating a focused signal from a disperse one. Most research modeling the behavior of TRCs is more concerned with their physics, so there is relatively little commented on the form of their signals. Data of a real impulse response measured using an acoustic reverberant chamber wa used to model the time-frequency behavior of these systems
Air Coupled Impact Echo Testing of Buried Concrete Pipes
Get PDFConcrete pipes constitute an integral part of the buried infrastructure, and non-destructive testing (NDT) plays an important role in their maintenance effort. Impact echo (IE) is a well-established NDT technique that is widely used for the investigation of concrete structures. In this technique, the thickness (or resonant) frequency is first measured by inducing (compression) P-wave into the structure using an impact source and recording the elastic wave generated using an accelerometer. From the knowledge of P-wave velocity of the medium, the unknown thickness and subsurface defects are then established. To effectively apply this technique, the transducer should be properly coupled with the surface. However, this often becomes a difficult task due to the poor surface quality of concrete. Alternatively, instead of capturing the elastic wave with a contact-based transducer the leaky acoustic wave that accompany the elastic wave is captured with a microphone and the thickness frequency is calculated. This non-contact variation of IE is called the air-coupled IE (ACIE) and it has been shown to be effective for testing plate like concrete structures (e.g., pavements and bride decks). In this dissertation, the feasibility of ACIE for the NDT of buried concrete pipe is investigated. The investigations are conducted in two stages. First, numerical modelling is conducted to test the effectiveness in pipes and then experimental validations are conducted. A structural-acoustic coupled finite element model is created using the COMSOL Multiphysics software, and the propagation of elastic and acoustic waves in a fluid-filled concrete pipe is simulated for standalone and buried pipe. The effectiveness of ACIE is studied when a pipe is surrounded by soil. Two types of soil surrounding the pipe studied to learn more about the quality of the data that might be anticipated from ACIE technique inside the pipe. Using these models, various aspects of ACIE are studied and its performance against the conventional IE is compared. Following the numerical verifications, two laboratory tests setups are constructed with a standalone and buried reinforced concrete pipes (RCP) and ACIE is demonstrated using them. The (unknown) wall thickness is calculated in each case and the results are compared against the conventional contact-based technique. While the presence of soil caused energy losses which affected the amplitude of acoustic wave, it was enough to be detected with good signal to noise ratio.
Several enhancements to improve the performance of this technique are studied. For instance, a way to improve the signal-to noise ratio of the acoustic signal is investigated using noise suppressers. For rapid implementation of technique and fast data gathering a semi-automated ACIE setup is also developed. Finally, the ability of the technique to detect several commonly occurring problems in a concrete pipe is investigated.
In summary, ACIE technique shows promising results for buried pipe testing
Risk-Based Decision-Making Modeling for Wastewater Pipes
Get PDFThe dissertation research work described here has three primary objectives under risk-based decision making. (1) The development of a comprehensive sewer pipe condition rating model that incorporates many environmental, structural, and hydraulic parameters. (2) The development of a sewer pipe deterioration model used to predict future overall condition states of the pipe, as well as determining the probability of failure at any given age of the pipe. (3) The development of a comprehensive consequence of failure model that assesses the consequence of sewer pipe failure using economic, social, and environmental cost factors.
The Pipeline Assessment and Certification Program (PACP) was developed by the National Association of Sewer Service Companies, the industry-accepted protocol for condition rating sewer pipes in the US. The PACP method relies exclusively on visual inspections performed using Closed-Circuit Television (CCTV), where existing structural and operation and maintenance (O&M) defects are observed by certified operators. A limitation of the PACP method is that it does not use pipe characteristics, depth, soil type, surface conditions, pipe criticality, capacity, the distribution of structural defects, or history of preventative maintenance to determine the condition rating of the sewer pipe segment. Therefore, a comprehensive rating model with pipe characteristics, external characteristics, and hydraulic characteristics was developed. The calculating of a comprehensive rating is an entirely manual process.
Therefore, this research work addresses this limitation of Analytical Hierarchy Process (AHP) and suggests AHP is not a suitable method to calculate comprehensive rating. Develops a faster calculation of a comprehensive rating model using and K-NN that incorporates pipe characteristics, environmental characteristics, and information about PACP structural score and PACP O&M score in hydraulic factors. Factors such as pipe age, pipe material, diameter, shape, depth, soil type, loading, carried waste, seismic zone, PACP structural score, and PACP O&M score are used. Our proposed model is applied to the data received from the City of Shreveport, LA, which is currently under a Federal Consent Decree. The results of a comprehensive rating model showed a below-average validity percentage because linear regression assumes a linear relationship between the input and output variables. Still, the relationship between response and the predictor is not linear for AHP to prove AHP is not a suitable method and satisfactory results for K-NN.
As part of decision-making, for capital improvement planning and budgeting, the capacity to predict future sewer pipe conditions and potential breakdowns is essential. In contrast to the often-used Discrete Time Markov Chain approaches in the literature, the deterioration model created here uses a Continuous Time Markov Chain method to calculate the likelihood that a pipe will change from a better to a worse condition at given age.
The consequence of the pipe\u27s failure is established to ascertain the risk of failure and to create a comprehensive framework for risk-based decision-making. To estimate the impact of the asset\u27s failure, the established consequence of failure model considers a significant number of economic, social, and environmental cost elements. For budgeting future capital projects and improvements, the CTMC model and failure consequences for sewers are useful
Nutritional Adequacy of Dietary Intake Among College Students Who Follow a Veget
Get PDFIn recent years, forms of the vegetarian diet have been popularized for various reasons, including health benefits, support of animal rights, and greater sustainability claims. The purpose of this cross-sectional study was to examine the diet quality and adequacy and iron status of college students’ diets, and compare eating disorder (ED) risk between self-proclaimed vegetarians and non-vegetarians. The study sample was a convenience sample of students at Louisiana Tech University who were 18 years of age or older (N = 179). Students were recruited via email, flyers, and classroom announcements. Participants completed an online questionnaire with multiple validated tests; The Rapid Eating Assessment for Participants – Shortened Version (REAP-S) for diet quality, the Bratman Test for Orthorexia, and the SCOFF Questionnaire for eating disorder risk.
There were 179 participants included in the analysis for this study. The mean age was 21 +/- 4.6 years; majority were female (n = 129, 72.07%) and White (n = 134, 74.86%). Body Mass Index (BMI) ranged from 16.8 to 46.4, with a mean BMI of 25.7 (SD = 5.7). Four (2.25%) participants were categorized as underweight, 94 (53.12%) as healthy weight, 46 (25.99%) as overweight, and 33 (18.64%) as obese.
A significant, inverse relationship was found between REAP-S scores and BMI; an increased diet quality was linked with a lower BMI. This is consistent with the literature supporting that a healthy diet can mitigate overweight and obesity among the college population. Participants averaged a score of 27.1 out of 39 on the REAP-S, indicating moderate diet quality, indicating that there are still improvements to be made. A number of participants, 38.20% (n = 68), reported eating less than two servings of fruit daily, and 29.21% (n = 52) reported eating less than two servings of vegetables daily.
The mean hemoglobin level for females was 14.09 g/dl (SD =1.36). Twenty-four percent of the females were found to have below-normal hemoglobin levels (Hbg \u3c 12.1 g/dl), 72.22% had normal hemoglobin levels (Hgb 12.1-15.1 g/dl), and 3.70% had high levels (Hbg \u3e 15.1 g/dl). The mean hemoglobin level for males was 15.87 (SD =1.48). Three (6.25%) males had below-normal Hgb levels (Hgb \u3c 13.1 g/dl), 62.50% had normal hemoglobin levels (Hgb 13.1-16.6 g/dl), and 31.25% high levels (Hgb \u3e 16.6 g/dl). There was a positive correlation found between BMI and Hemoglobin levels for males r (48) = .348, p = .018. No significant correlations were found between Hgb and the BOT, SCOFF, or REAP-S scores. There were no significant correlations found between Hbg and BMI, BOT, SCOFF, or REAP-S scores for the female group.
A significant, positive correlation was found between SCOFF scores and Bratman Test scores, r (176) = .167, p = \u3c .001. As the risk of having an eating disorder increased, so did the risk of experiencing orthorexia. A significant, positive correlation was also found between REAP-S scores and Bratman Test scores, r (171) = .382, p = \u3c .001, indicating that higher diet quality scores were associated with higher risks for orthorexia. A significant, inverse relationship was found between REAP-S scores and BMI, r (158) = -.167, p = .036; as diet quality increased, BMI decreased. To further explore the relationships among participant characteristics, participants were divided into health-related or non-health-related groups. Both the REAP-S scores and Bratman Test results were found to be significantly different between the groups, t (170) = 4.06, (p = \u3c .001) and t (175) = 3.00, (p = .003), respectively. Health-related majors were found to have greater diet quality scores and a higher risk of eating disorders when compared to non-health-related majors.
Having a very small percentage of vegetarian and vegan participants limited full analysis related to vegetarianism. However, this study provides nutrition professionals with valuable information regarding diet adequacy, eating disorder risk, hemoglobin levels, as well as the prevalence of vegetarianism among college students at Louisiana Tech University. Specifically, these results indicate that students in health-related majors may be at greater risk for orthorexia as they strive for higher diet quality and might also be at greater risk for other eating disorders. Results also indicated that students who maintain a diet of higher quality might have lower BMIs than their peers
The Role of Notch3 in Human Adipose Stem Cell Fate
Get PDFStem cell-based therapies are the future of medicine, as their natural abilities of self-renewal and differentiation have the potential to treat currently incurable diseases. Stem cells are categorized based on differentiation potential, with multipotent stem cells being the most differentiated while still having the ability to divide down defined lineages. Adipose stem cells (hASCs) are easily derived multipotent, mesenchymal stem cells with already demonstrated therapeutic potential. Despite current success, there are a multitude of factors that regulate the physiology and role of adipose stem cells, including transduction pathways and transcription factors, that remain to be researched and fully understood. One such transduction pathway –the Notch signaling pathway– is known to be crucial in stem cell proliferation, differentiation, and apoptosis in all animals. The focus of my research is on Notch3, one of four Notch transmembrane surface receptors involved in stem cell fate determination, embryonic development, and some forms of cancer. I utilized siRNA-mediated knockdowns of Notch3 to evaluate its role in stem cell proliferation, self-renewal, metabolism, and morphology. Results have indicated that Notch3 plays a highly active role in cellular proliferation and self-renewal, while not eliciting an effect on metabolism and morphology. This data continues to drive the research into stem cells and their regulators forward, bringing us one step closer to finding curative degenerative disease treatments
Incorporating Active Learning into Breastfeeding Education and Lactation Management Training of the Future Registered Dietitian Nutritionist
Get PDFBackground: Breastfeeding has been shown to have multiple benefits for mother and child, yet rates of breastfeeding continue to stay insignificant. Infant nutrition is the base of future health of an individual, yet Registered Dietitians are not provided in depth breastfeeding education during their education.
Objective: The purpose of this study is to evaluate the active learning component of breastfeeding and lactation education modules meant to increase self-efficacy and confidence in the ability to perform lactation education and to obtain feedback regarding the usefulness of the developed education modules in graduate-level dietetic interns.
Design: This study was part of a larger breastfeeding education intervention with Dietetic Interns (N=38). The research took place in classrooms and online at the University of Texas Medical Branch, Louisiana Tech University, and the University of Central Arkansas. A pre-and post-test design was used to compare changes in self-efficacy related to the ability to provide nutrition services related to lactation after completing four breastfeeding education and lactation management modules.
Results: Of the respondents (n=31) 45% scored a 4 or 5 in all categories of gains questions. The greatest gains (scores of 4 or 5) were seen for “confidence in the understanding of types of infant stool” (87%) “ability to pour and store breastmilk correctly” (77.4%), “correct positioning of the bottle when bottle feeding an infant with breastmilk” (70%), and “ability to demonstrate infant stomach size” (74.2%). All self-efficacy items had statistically significant increases in scores when pre-intervention scores were compared to post-intervention scores. During reflections, participants verbalized positive important gains related to the active learning strategies applied in the intervention.
Conclusion: Participants felt hands-on active learning had a positive impact along with traditional lecture-style coursework. Providing future registered dietitian nutritionists with hands-on lactation education could increase their self-efficacy and confidence in the ability to provide lactation education in the future
A Model Knight: Sir Gawain, Chivalric Contradictions, and Grief in Medieval Literature
Get PDFScholarship on medieval and Arthurian chivalry in recent decades has focused largely on the Gawain Poet’s 1375 Sir Gawain and the Green Knight and Sir Thomas Malory’s 1470 Le Morte D’Arthur. These two romances seem to offer more critical looks at the chivalric system than the glorification of knightly life provided by romances from the previous centuries of the high medieval period. In past works such as L’atre Périlleux and Claris et Laris, Sir Gawain is depicted as the ideal knight—in these poems he is humble, strong, noble, and always perfectly in accord with the chivalric code. In Sir Gawain and Morte, however, Gawain comes to represent the inconsistencies within chivalry and its conflicts with medieval Christian principles. In Sir Gawain and the Green Knight, Gawain makes a crucial mistake that suggests he, as a human being, cannot achieve perfect chivalry, and that the chivalric expectations to which knights are held contradict the instinct of self-preservation as well as Christian values of life and mercy. Meanwhile, Gawain’s vengeful reaction to the death of a loved one in Morte D’Arthur demonstrates how the chivalric ethos can allow for a knight to handle complex emotions in a destructive and violent manner as opposed to the Church-endorsed route of penitence and peaceful resolution. In discussing the complexities of medieval chivalry and the consistent use of Gawain’s character as its representative, this analysis will consider medieval writings on chivalry, grief, and Christianity as well as recent scholarship on Sir Gawain, Morte, and minor French romances involving Gawain. Research for this project will explore the way that Sir Gawain’s character transformed from being the symbol of the model knight to emblematic of the conflicting qualities of the chivalric code and its opposition to Christian principles
Assessment of Human Performance in Industry 5.0 Research Via Eye-Tracking and Cognitive Biases
Get PDFManufacturing assembly is combining previously made components or subassemblies into a final finished product. The assembly process can be manual, hybrid, or fully automated. Human operators who are involved in assembly use their judgment to perform the process. They collaborate with the other work agents such as assembly machines, robots, smart technologies, and computer interfaces. The recent Industrial revolution, Industry 5.0, exploits human expertise in collaboration with efficient and accurate machines. Manufacturing facilities that feature Industry 5.0 work settings require higher expectations, higher accuracy, sustainability solutions, mass customization of products, more human involvement, and digital technologies in smart workstations. Given these features, the cognitive load exerted on human workers in this environment is continuously increasing, leading to the use of cognitive heuristics. Cognitive biases are getting more attention in the cognitive ergonomics field, to help understand the operational behavior of workers. Manufacturing facilities can integrate cognitive assistance systems to work in parallel with physical and sensorial assistance systems. Cognitive assistance systems help toward better work conditions for workers and better overall system performance. This research explores the impact of human thinking style and using a cognitive assistance system on workers\u27 cognitive load, bias-related human performance, and user satisfaction. This research presents the design and experimental implementation of a research framework based on a well-established three-layer model for implementing Industry 5.0 in manufacturing. The research framework was designed to apply the dual-system theory and cognitive assistance in Assembly 5.0. Two experiments are presented to show the effectiveness of the proposed research framework. A cognitive assistance system was designed and compared to a benchmark system from LEGO ® Company. Subjective and objective measures were used to assess the thinking style, cognitive load, bias-related human performance, and user satisfaction in Assembly 5.0. As Industry 5.0 requires higher expectations, higher accuracy, smart workstations, and higher complexity, cognitive assistance systems can reduce the cognitive load and maintain the work efficiency and user satisfaction. Therefore, this work is important to industry to expand the use of cognitive ergonomic tools and employ them for A5.0 workers\u27 benefits
Examining Representation of Gifted Students in an Urban Gifted Education Program Through the Lens of Social Capital Theory and Culturally Relevant Leadership
Get PDFGifted education has been permeated with discrepancies in representation since its inception. Despite efforts to minimize the gifted gap, under identification of minority groups continues. A gifted student’s social capital and a school district’s execution of culturally relevant leadership may impact underrepresentation. Therefore, an instrumental case study was implemented to understand, through a social capital and culturally relevant leadership lens, how gifted policy impacts representation of students in a gifted education program in an urban school district. Gifted identification relies heavily on teacher recommendations, which is why it is essential to understand educators’ perceptions of giftedness when investigating underrepresentation. Twenty educators were surveyed, and twenty-two educators and leaders were interviewed to explore perceptions of giftedness and the district’s current gifted education program.
Educators’ and educational leaders’ perceptions of giftedness are similar; however, educators acknowledge more need for the social and emotional development of gifted students. Educators and leaders perceive social capital to be an essential component for identification. Elements of culturally relevant leadership are present; nevertheless, a better understanding of the gifted education program is necessary for educational leaders to challenge underrepresentation and induce change in the gifted education program. Educators and leaders at the secondary level do not prioritize gifted education, though they understand the importance of meeting gifted students’ educational needs. Additionally, educators and leaders acknowledge the need for policy reform.
Results indicate that implementing the following could lead to an increase in identification: provide professional development on gifted characteristics and the gifted identification process; implement forms of culturally relevant leadership; incorporate an equity policy and scrutinize gifted numbers
Coaching Isn\u27t Just for Little League Anymore: A Theory of Individual Coachability
Get PDFUtilizing coaching as an employee development activity has increased significantly in the practitioner space in recent years. Practitioners have implemented coaching in the modern organization, establishing best practices for both coaches and coachees. Coaching is a dyadic relationship whereby the coach and the coachee play a critical role in the successes obtained by the relationship. Previous academic research in a variety of disciplines, including athletics, entrepreneurship, marketing, and management, has studied the coach/coachee relationship extensively from the perspective of the coach. Although the coach’s perspective is important, practitioners and academics agree that individual coachability is a key individual characteristic of a coachee for coaching success. However, there has been little research evaluating the individual coachee. Further, what little research there is, presents inconsistencies in regards to what makes an individual coachable. Therefore, the purpose of this dissertation is to establish a theory of individual coachability by defining individual coachability and empirically evaluating its elements.
Theory development begins with a rigorous literature review. I thoroughly examine current coaching literature, establishing the need for a theory of individual coachability. Through inductive and deductive research, I establish that goal-setting, self-efficacy, feedback, and accountability are important elements of individual coachability. Rooted in the newly developed theory, I define individual coachability for universal use across all areas of research. I achieve this through a series of empirical studies. In Study 1, I develop a measure of coachability, establishing that coachability is a second order construct. I conduct an exploratory factor analysis to confirm the structure. In Study 2, I test the convergent and discriminant validity of the developed scale by comparing it to existing constructs. I conduct a confirmatory factor analysis to establish validity of the constructs in the measurement model. In Study 3, using the established scale from Study 2, I conduct an experiment, using experimental vignette methodology, to observe whether individual coachability influences the relationship between the quality of an organization’s developmental coaching program and various organizational outcomes. More specifically, I hypothesize that the quality of the developmental coaching program and individual coachability will interact to predict job performance, employee engagement, and organizational commitment. I also hypothesize that when a workplace has no developmental coaching program, job performance, employee engagement, and organizational commitment for those high in coachability will be higher than for those who are low in coachability