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Title: Do Numeric Performance Ratings Have Any Merit?
Creator: Sanders, Emily Kathleen
Date: 2022
Description: Numeric performance ratings have been a component of performance evaluation for decades (Prowse & Prowse, 2009; Pulakos, Mueller-Hanson & Arad...
Show moreNumeric performance ratings have been a component of performance evaluation for decades (Prowse & Prowse, 2009; Pulakos, Mueller-Hanson & Arad, 2019). Yet, in recent years their necessity has been questioned (Adler, Campion, Colquitt, Grubb, Murphy, Ollander-Krane, & Pulakos, 2016), with some organizations going so far as to remove numeric ratings entirely (Capelli & Tavis, 2016; Rock, Davis & Jones, 2014; Burkus, 2016). Unfortunately, this practice has been largely unexamined in an empirical manner. The present study tested whether the claim – that numeric ratings do not matter – holds up in all cases. This is done by exploring whether the presence or absence of numeric ratings, impacts employee perceptions of fairness associated with the appraisal. As numeric ratings are argued to be a mechanism for communicating a fair, standard, and consistent practice, the study aimed to understand if the mere presence of numeric ratings may offset some of the negative reaction employees have toward performance appraisal when they have poor-quality relationships with their supervisors. Findings indicated that while employee-manager relationship quality (assessed via Leader-Member Exchange) has a direct relationship with perceptions of fairness associated with the appraisal, the presence of numeric ratings did not moderate this relationship. Practical implications and future research recommendations are discussed.
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Title: Toward an Extraordinary Ecotourism Destination on The Shoreline of Aseer Region, Kingdom Of Saudi Arabia
Creator: Saleh, Abdulmalik Mohammad S.
Date: 2022
Description: Since the dawn of the Anthropocene epoch, human activities have been adversely influencing our globe and becoming a controversial phenomenon....
Show moreSince the dawn of the Anthropocene epoch, human activities have been adversely influencing our globe and becoming a controversial phenomenon. However, as a counterforce, multiple adoptions of sustainable green movements worldwide are continually attempting alternate resolutions to preserve nature. As the tourism industry grows, ecotourism, for instance, is a specific eco-friendly approach that asserts minimizing human impacts and conserving captivating nature, improving the livelihood of local communities, and involving interpretation and education. A demi-decade ago, Saudi Arabia’s 2030 vision (the post-oil plan) was launched to diversify its GDP and develop public service sectors such as tourism. This thesis investigates the relationship between architecture and the possibilities of ecotourism principles, besides the governmental program, under multiple tourism indicators along the untouched Aseer shoreline, which has valuable attractions and amenities; it is faced with several issues, including informal planning, limited infrastructure, and low-income community. We built a suggested project based on a collection of written materials on the area’s environmental and culturally diverse aspects and case studies; architecture-to-ecotourism is thriving, but there is still potential for methodological development. The thesis findings demonstrate that architecture can immensely contribute to sustainable development through the ecotourism concept and can have a tangible impact on the project. Simultaneously, architecture, through ecotourism, is successful by improving the economic aspect of the host societies, reducing environmental consequences, and strengthening heritage identity. This research needs further studies on the correlation, which remains highly debated, between architecture and ecotourism norms to sustain nature.
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Title: Stimulation-Responsive Materials for the Treatment of Disordered Tissues
Creator: Clutter II, Elwin Dean
Date: 2022
Description: Microenvironments offer physical and chemical cues to cells that affect their behavior. These cues can be bioactive chemicals such as drugs...
Show moreMicroenvironments offer physical and chemical cues to cells that affect their behavior. These cues can be bioactive chemicals such as drugs and cytokines, matrix cues like stiffness and composition, and electrical signals as seen in membrane potentials and epithelial wound healing. Controlling these cues can drive cell behavior toward apoptosis, proliferation, or changes in protein expression. In this thesis research, three components were used to model changes in cell behavior: the near infrared dye indocyanine green (ICG), silk fibroin (SF) from Bombyx mori silkworm cocoons, and carbon nanotubes (CNT). The mechanism of ICG photobleaching was studied for the efficacy to kill neuroblastoma cancer cells. ICG was twice as effective at killing neuroblastoma than fibroblast cells. Albumin stabilized monomeric ICG to enhance photobleaching by improving light interaction, and photodegradation of ICG into α,β-unsaturated aldehydes led to significant reduction of proliferation in neuroblastoma cells by targeting cell signaling components such as protein transcription factors. SF-ICG composite materials were developed into films and electrospun fibers. These composite materials were examined as light-activated wound coverings to control bleeding in hemorrhage, using ICG’s photothermal effect. ICG added an absorbance peak to SF at 805 nm. Irradiation decreased this peak, produced a new absorbance peak at 352 nm, and an increased fluorescence peak around 490 nm, showing photochemical changes that may be useful in sensor design. Increased heat production from irradiation of SF-ICG occurred in the films with 0.2% w/w ICG in SF during 1 min irradiation, whereas SF-ICG fibers required improvement of processing by ethanol vapor treatment (EVT) to reduce loss of ICG during preparation. EVT improved ICG retention in SF fibers during sterilization with 70% ethanol solution thus improving heat generation in the SF-ICG fibers. Heat evolved from SF-ICG 0.2% film solidified bovine blood within 42 s, with visible changes after the first 6 s. SF electrospun fibers were investigated to optimize silk preparation to reduce diameters and increase alignment to mimic local native cell environments with and without CNT to add conductivity for enhancement of electrical stimulation. CNT reduced SF fiber diameters below 1% and effected alignment differently as the concentration increased. Longer degumming times decreased SF fiber diameters and alignment of the same concentration. The optimized conditions were 1 h degumming time with 1.5 ml/h flow rate at a concentration of 100 mg/ml spinning solution with 0.25% CNT to form fibers with 1.36 (± 0.09) µm diameter and 0.31 (± 0.01) a.u. alignment. Additionally, SF fibers were used as a long-term cell growth scaffold to compare with decellularized native tissue. Decellularized tissue decreased fibroblast mRNA expression of collagen type 1, lysyl oxidase-like 1 and matrix metalloproteinase 9, while all other genes expression was the same as cells on plastic. The SF fiber scaffold reduced fibroblast expression of collagen type 3 compared to growth on plastic, and both collagen types 1 and 3 increased over growth time on SF. Immunofluorescence staining showed both collagens newly deposited on the SF scaffold and improved over time. In conclusion, proteins stabilized ICG monomers to improve light interaction, efficacy of photobleaching, and heat evolution to induce apoptosis in neuroblastoma and agglutination of blood in SF composites. Irradiation of ICG enhanced changes in optical properties and may have sensor applications. The decrease of genes may be due to each scaffold having lower stiffness compared to plastic. ICG and SF are both materials with applications as biological scaffolds in pelvic organ prolapse and treatment of neuroblastoma and hemorrhage.
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Title: Fatigue Life Prediction for Structures with Interval Uncertainty
Creator: Desch, Michael R.
Date: 2022
Description: A new method for reliable fatigue life prediction in metal structural components is developed where uncertainties are quantified using...
Show moreA new method for reliable fatigue life prediction in metal structural components is developed where uncertainties are quantified using interval variables. Using this crack-initiation-based method, first, the uncertainties in laboratory test data for the fatigue failure of a structural detail are enumerated. This uncertainty quantification is performed through an interval-based enveloping procedure that relates the interval stress ranges to the number of cycles to failure, leading to the construction of an interval S-N relationship. Next, the uncertainties in field test data are enumerated in the extremum values of each stress range, as intervals, leading to the construction of interval stress ranges. For both the laboratory and field data uncertainty analyses, the mean stress effects are considered. Next, the interval damage accumulated over the duration of the field data is determined using the constructed interval S-N relationship and the obtained interval stress ranges. Then, the interval existing damage and interval remaining life are determined. Finally, as a conservative measure, the minimum remaining fatigue life is obtained in which all uncertainties are considered. Three numerical examples illustrating the developed method are presented, and the results are compared with results obtained by both Monte Carlo simulation and optimization. Using this method, for the numerical examples considered, it is shown that the results for bounds on the existing damage and the remaining fatigue life are sharp. Moreover, due to its set-based approach, the method is significantly more computationally efficient when compared with iterative procedures.
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Title: Stress-Induced Habitual Responding as a Maintenance Factor in Bulimia Nervosa Spectrum Disorders
Creator: Dougherty, Elizabeth Nash
Date: 2022
Description: Individuals with bulimia nervosa spectrum disorders often compulsively engage in binge eating and purging, despite life threatening...
Show moreIndividuals with bulimia nervosa spectrum disorders often compulsively engage in binge eating and purging, despite life threatening consequences. Little is known about factors that contribute to compulsivity in these conditions. The purpose of this study was to investigate whether stress and habitual control over bulimic behaviors play a role in maintaining symptoms in these disorders, using ecological momentary assessment. Women with bulimia nervosa spectrum disorders (N = 81) completed self-report baseline questionnaires and a 14-day EMA protocol which involved daily assessments of stress, negative affect, bulimic behaviors, and contextual antecedents to bulimic behaviors. The results indicated that baseline habitual control over binge eating and purging were not associated with global eating pathology or eating disorder-related clinical impairment. However, exploratory analyses revealed that habitual control over binge eating and purging were associated with more frequent engagement in these behaviors during the previous four weeks. Neither stress appraisal nor stressor frequency were associated with habitual control over bulimic behavior during the EMA period. In terms of affect trajectories surrounding bulimic behaviors, negative affect increased in the hours leading up to these behaviors, decreased in the hours following these behaviors, and was higher immediately after these behaviors compared to before. Habitual control over binge eating and purging did not moderate temporal relations between negative affect and bulimic behaviors during the EMA period. Overall, the findings suggest that habit may play a role in maintaining binge eating and purging.
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Title: Effect of heat treatment on microstructure and electrochemical behavior of laser powder bed fusion hydride- dehydride ti-6al-4v alloy
Creator: Delpazir, Melody Honardan
Date: 2022
Description: In powder bed additive manufacturing, feedstock and processing have an impact onfinal microstructure and properties of 3D-printed parts. While...
Show moreIn powder bed additive manufacturing, feedstock and processing have an impact onfinal microstructure and properties of 3D-printed parts. While numerous studies have evaluated 3D-printing of spherical powder, very limited research has been carried out on the processing of the non-spherical feedstock. This study is targeted specifically to the use of non-spherical Ti-6Al-4V powders in the laser powder bed fusion (L-PBF) process. Two different post-heat-treatments including hot isostatic pressing and solution treatment are applied. The microstructure evaluation, potentiodynamic polarization, and electrochemical impedance spectroscopy methods are used to characterize L-PBF processed and post- treated specimens. Though as-built part exhibits anisotropic microstructure containing acicular α′ martensite with trace amount of β phase, the heat-treated parts are composed of α+β in which length and thickness of the α-lath depends on the treatment. The below β transus heat treatment leads to the formation of a homogenized grain structures composed of α+β. Electrochemical results show that the below β transus heat-treatment had a slight positive effect on the improvement of corrosion resistivity (corrosion rate of 4.2×10-6 mmy- 1 , which is classified as an excellent ) compared to other conditions, which would be associated to the natural excellent corrosion resistance of Ti-6Al-4V alloy. This slight improvement can be ascribed by the slightly faster formation of a passive layer and its enhanced efficiency because of the presence of the fine-structured β phase in post heat- treated L-PBF processed Ti-6Al-4V alloy.
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Title: DOES FAMILY QUALITY OF LIFE MEDIATE THE RELATION BETWEEN AUTISM WAIVER SERVICES AND CHILD PROGRESS?
Creator: Desai, Shivani S.
Date: 2022
Description: Autism Spectrum Disorder (ASD) is a pervasive neurodevelopmental disorder that affects a child’s language, social, and behavioral development,...
Show moreAutism Spectrum Disorder (ASD) is a pervasive neurodevelopmental disorder that affects a child’s language, social, and behavioral development, and also is associated with difficulty with academics, independent completion of daily living skills, and emotion regulation. Diagnosed individuals often require comprehensive, long-term, and family-based intervention that is costly. Several states, including Maryland, have adopted Medicaid Home and Community Based Services (HCBS) waiver services that specifically serve children and young adults with ASD at no out-of-pocket cost to families. The Maryland autism waiver (AW) also includes services to support diagnosed individuals’ family members, including family consultation and respite services. Family factors, such as specific parenting behaviors and parental mental health, contribute significantly to symptom improvement in children with ASD and child development more broadly, highlighting the importance of studying family systems and targeting them in treatment. Prior research has found that AW services have a positive impact on family quality of life (FQoL), which is a multidimensional concept of family functioning. The aim of the present study was to examine if the several domains of FQoL are mediators in the relation between receipt of Maryland HCBS AW services and caregivers’ perception of their child’s improvement in several domains of functioning. The participants in this study consisted of 460 families who were enrolled in a larger study examining effects of Maryland AW services. Half of these families (n = 230) received the Maryland Medicaid AW services (n = 230) and the other half were on a registry to receive services (n = 230). Deidentified survey data were collected between 2013-2016 from caregiver informants who had a child under the age of 21 who exhibited symptoms of ASD. The survey included questions about demographics, FQoL, and their child’s progress in the areas of academics, independent living skills, social communication skills, stereotypic and repetitive behaviors, and aggressive behaviors over the past 6 months. Results of the mediation analyses revealed that FQoL in the domains of parenting, emotional well-being, and disability support services (but not in the domains of family interaction and physical/material well-being) each mediated the relations between AW services and caregiver report of improvement in all measured domains of child functioning (academics, independent living skills, social communication skills, stereotypic and repetitive behaviors, and aggressive behaviors). These findings highlight the significant role of FQoL as a mediator in the relation between waiver serves and child outcome. They also reveal the importance of increasing family quality of life when providing treatment services to children with symptoms of autism and their families.
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Title: WIDE BANDGAP FRACTIONAL POWER PROCESSING
Creator: Kundu, Aritra
Date: 2022
Description: The adoption of wide bandgap (WBG) power semiconductors can improve the performance of power converters at the expense of significantly higher...
Show moreThe adoption of wide bandgap (WBG) power semiconductors can improve the performance of power converters at the expense of significantly higher cost than Si at present time. In this thesis, an innovative Wide bandgap Fractional Power Processing (WFPP) design concept is introduced where silicon devices process the base power at a low switching frequency (2kHz or lower) while WBG devices are judiciously used to process only a fraction of the total power at a much higher frequency (tens of kHz). WFPP inverter is a design concept that splits the power processing into a low frequency Si base power processor and a high-frequency WBG fractional power processor. WBG devices are therefore judiciously used to process only a fraction of the total power to achieve both high-efficiency and lower cost than a full-WBG converter design. This thesis investigates an optimization strategy to minimize the total power loss while maintaining a reasonable THD and cost for a hybrid inverter design with comprehensive power loss analysis and calculation on fundamental and harmonics currents. Optimal selection of power sharing between the Si and WBG inverters and switching frequency are discussed in the thesis. The circulating current paths in topology with hybrid switching frequencies are also analyzed and presented in this thesis. Experimental results on a 9kW SiC/Si hybrid inverter prototype with isolated and non-isolated DC power supplies are presented to validate the design concept.
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Title: STRUCTURE AND DYNAMICS OF MODIFIED NUCLEOSOMES UNDER EPIGENETIC REGULATION
Creator: Kohestani, Havva
Date: 2022
Description: Epigenetic regulations are critical in inducing heritable phenotype changes in biological systems without alternating their core genetic DNA...
Show moreEpigenetic regulations are critical in inducing heritable phenotype changes in biological systems without alternating their core genetic DNA sequences. In vivo, reversible epigenetic mechanisms engage various molecular structures from RNAs to larger proteins. The present thesis investigates the influence of epigenetic regulatory factors such as histone protein variants and small non-coding RNAs on the dynamics and structure of nucleosome core particles. Our results show that a histone substitution is an efficient tool in increasing or decreasing the exposure of DNA to post-translational modification (PTMs) factors or larger molecular assembly elements. Substitution of canonical H2A with H2A.B alters DNA-dimer interface resulting in increased breathing and accessibility of DNA. Replacement of canonical H3 with CENP-A variant impacts the overall core-DNA dynamics with flexibility of DNA entry/ exit sites and more rigid tetramer structure. Histone substitution also affects the micro to macro level molecular communication in the nucleosome system. The long-range correlated motions are weakened in H2A.B compared to canonical NCP. We observed a reduction in effective long-range DNA-DNA and DNA-core allosteric pathways in CENP-A NCP compared to canonical and Widom NCPs. Non-coding RNAs increase the tendency of the H3 tail histones to interact with DNA and induce the structural changes in the initial ideal B-DNA of NCP. Overall, the interaction of epigenetic regulatory factors in the form of protein or nucleic acids shifts the energetic and structural properties of the original nucleosome system. As a result, the chromatin structure is prepared to generate the proper biological response throughout spermatogenesis, chromosome segregation, or PTMs assembly.
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Title: PREDICTING AND SIMULATING OUTDOOR THERMAL COMFORT-BASED HUMAN BEHAVIOR IN URBAN ENVIRONMENTS
Creator: Khan, Zahida Marzaban
Date: 2022
Description: Rapid urban growth due to a constant rise in world population has amplified the need for sustainable design development of cities. Human...
Show moreRapid urban growth due to a constant rise in world population has amplified the need for sustainable design development of cities. Human behavior, a key performance metric of sustainable design, can be rewarding for urban policies and city planning. Due to its complex nature, human behavior prediction and simulation are increasingly challenging. Complexity is associated with multiple factors, among which social and environmental factors are critical, especially in urban conditions with tall buildings that create unique microclimates. Human behavior in this study referred to human spatial behavior. This research hypothesized that the microclimatic variations at seasonal and diurnal levels affect people’s behavior in outdoor urban environments. Additionally, interdisciplinary crossover studies on novel methodologies to predict human behavior is becoming popular. Moreover, architects and urban designers are interested in human behavior simulation tools that can help them make informed design decisions through ‘what-if’ scenarios and assess their designs before execution. This doctoral research investigated the inter-relationship between Outdoor Thermal Comfort (OTC), human behavior, and urban morphology for Plazas in urban conditions with tall buildings and within a specific climate zone. The study focused on two overarching objectives: (1) to present a novel research methodology to investigate and predict OTC-based human behavior in urban conditions; and (2) to develop HuBeSIM - a human behavior simulation framework using an agent-based model (ABM) to simulate OTC integrated human behavior in outdoor spaces. Daley Plaza – an urban public space built-in 1965 in downtown Chicago — was used as (1) a case study to test the feasibility of this research methodology and (2) a pilot study to demonstrate the HuBeSIM framework. The outcome of this study shows a significant impact in the outdoor urban environments with design goals that use human behavior as a key performance indicator. The research contributes to the modeling and simulation of OTC-based human behavior in urban environments to nurture livable communities and sustainable cities. The first part of the dissertation presented a novel research methodology involving data collection through an on-site observational study for behavioral mapping, and microclimatic CFD simulations for OTC index - Physiological Equivalent Temperature (PET). The sample data consisted of two seasons, namely summer and fall, with more than 600 observations collected during the three-hour lunchtime period. The second part of the dissertation involved developing a Human Behavior SIMulation (HuBeSIM) framework in the popular computer aided design platform Rhino® and Grasshopper® (GH). This part integrated OTC using physics-based modeling and human behavior using mathematical agent-based modeling to develop a simulation framework for outdoor urban space design. The findings from the observational study revealed a moderate relationship between microclimate and human behavior in the fall, and a weak correlation in summer. The results showed that people’s behavior is not affected by PET values above 35°C. The proposed Human Behavior SIMulation framework has a high potential to develop into a comprehensive model by incorporating other behavioral factors. This study contributes to the sustainable built environment design that leads to the environmental, social, and economic upliftment of a city.
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Title: The Feasibility of Double-Skin Façades to Provide Natural Ventilation in Tall Office Buildings
Creator: Kim, Yohan
Date: 2022
Description: Many tall office buildings (i.e., buildings of or taller than 656 ft (200 m)) are on the rise around the world. The energy efficiency and...
Show moreMany tall office buildings (i.e., buildings of or taller than 656 ft (200 m)) are on the rise around the world. The energy efficiency and healthy environment of tall office buildings has become an important concern, given the current environmental challenges and health considerations. Natural ventilation has proven to be an effective passive strategy in improving energy efficiency and providing healthy environments given environmental challenges. However, such a strategy has not been commonly adopted to tall office buildings that traditionally rely on single-skin façades (SSFs), due to the high wind pressure that creates excessive air velocities and occupant discomfort at upper floors. Double-skin façades (DSFs) can provide an opportunity to facilitate natural ventilation in tall office buildings, as the fundamental components such as the additional skin and openings create a buffer to regulate the direct impact of wind pressure and the airflow around the buildings. Wind-driven natural ventilation has not been fully studied in DSFs as most previous studies focused on the stack effect. Moreover, the studies assumed that the indoor spaces are mechanically ventilated without regard to airflow behavior between the air cavities and the indoor spaces. This study investigates the impact of modified multi-story type DSFs on indoor airflow in a 60-story, 780-foot (238 m) naturally ventilated tall office building under isothermal conditions. Therefore, the performance of wind effect related components was assessed based on the criteria (e.g., air velocity and airflow distribution), with respect to opening size, number of openings per floor, cavity depth, and cavity segmentation. Computational fluid dynamics (CFD) software was utilized to simulate outdoor airflow around the tall office building, and indoor airflow at various heights in case of various DSF configurations. Two sequential CFD simulations were carried out not only to reduce computational time, but also to comprehensively analyze the impact of DSFs responding to positive and negative wind pressures on indoor airflow behavior. The CFD simulation results indicate that the outer skin opening is the more influential parameter than the others on indoor airflow behavior. On the other hand, variations of inner skin opening size help improve the indoor airflow, with respect to the desired air velocity and distributions. Despite some air vortexes observed in the indoor spaces, cross ventilation can occur as positive pressure on the windward side and negative pressure on the other sides generate a productive pressure differential. The results also demonstrate that DSFs with smaller openings suitably reduce not only the impact of wind pressure, but also the concentration of high air velocity near the windows on the windward side, compared to single-skin façades. Further insight on indoor airflow behaviors depending on various DSF configurations leads to a better understanding of the DSF design strategies for effective natural ventilation in tall office buildings. This study aims to develop a performance-based DSF design guideline to assist architects in their design of DSF components in the early design stage.
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Title: Keeping the Spark Alive: Examining Associations Between Technology Use For Cybersex, Health and Relationship Satisfaction In Long-Distance Relationships
Creator: Khan, Humza
Date: 2022
Description: Background: Technology is important to many romantic relationships, especially long-distance relationships (LDR), insofar as technology can...
Show moreBackground: Technology is important to many romantic relationships, especially long-distance relationships (LDR), insofar as technology can minimize the impact of the lack of proximity that is characteristic to LDR. Cybersex, a specific use of technology within romantic relationships, is associated with increased relationship satisfaction among partners in proximal relationships. Cybersex also relates to health broadly, and to anxiety and depression specifically, with mixed associations. Despite LDR lending themselves to cybersex, associations between cybersex, relationship satisfaction, and health have not been studied in LDR. This study has three aims: (1) to provide the first descriptive data related to cybersex behavior, relationship satisfaction and health in LDR; (2) to examine associations between cybersex behaviors and relationship satisfaction, and cybersex and health in LDR; and, (3) to test whether biological sex moderates cybersex-relationship satisfaction and cybersex-health associations among those in LDR. We predicted that cybersex behaviors would relate positively to relationship satisfaction for both males and females, although we predicted males would report stronger associations than females. We predicted cybersex behaviors would relate positively to health for both males and females, although we predicted females would report weaker associations than males. Methods: Participants (N = 146; 18 years or older; English speaking; in LDR for 3+ months) completed a paid online survey on relational experiences and health/well-being. Cybersex behaviors were assessed through an internally created “sex and cybersex behaviors” scale. Relationship satisfaction was assessed via the Couples Satisfaction Index (CSI). Both broad health, and anxiety and depression, were assessed with the PROMIS-29. Correlations were assessed between key study variables. Regression analyses were used first to test associations between cybersex and relationship satisfaction, then cybersex and health, and finally, the moderation effect of biological sex in these associations. Results: The average member of our sample was White, college aged, had no children, a full-time undergraduate student and low SES. Correlation analyses show significant correlations between core study variables (relationship satisfaction, global health, cybersex behavior, depression & anxiety) at some level. Sex-level analyses show that when compared to males, females reported significantly higher average anxiety scores, and more texting sex behavior. Linear regressions established cybersex behavior as a negative predictor of global health and a positive predictor of depression and anxiety, but not relationship satisfaction. Moderation analyses indicated that biological sex moderated the cybersex behavior-global health association such that more cybersex behavior negatively predicted global health for males but not females. Discussion: These differences among sexes and health in LDR observed within our findings may be explained by the social role theory, in which females have worse health than males however, males having worse overall physical health than females may be due to a lack of copresence from their partner. In addition, females engaging in higher levels of texting cybersex may be related to sociocultural factors. Conclusion: Overall, our study contributes to the understanding of cybersex behavior, relationship satisfaction and health outcomes by among males and females in LDR. Our findings suggest that this sample of LDR females engage in more texting cybersex, have higher anxiety symptom severity, and have equal levels of relationship satisfaction.
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Title: Efficacy of Organic Acid Treatments for the Reduction of Listeria Monocytogenes on Hard Boiled Eggs
Creator: Khouja, Bashayer
Date: 2022
Description: Ready-to-eat hard-boiled eggs (HBEs) are a popular and convenient choice for consumers and food servicers. Recentrecalls of hard-boiled eggs...
Show moreReady-to-eat hard-boiled eggs (HBEs) are a popular and convenient choice for consumers and food servicers. Recentrecalls of hard-boiled eggs have highlighted the susceptibility of contamination with Listeria monocytogenes. HBEs are generally treated with antibacterials to ensure the safety and quality of the product. While citric acid is often used, research has determined it is not effective in some situations; therefore, the assessment of additional organic acids is necessary. This study examined the efficacy of acetic, lactic, and malic acid on the reduction of L. monocytogenes on HBEs after a 24- hour treatment trials and 28 days storage trials. Fresh eggs were cooked in boiling water, peeled, and stored at 4°C for 24h before use. For treatment trials, HBEs were dip- inoculated with a 4-strain cocktail of rifampicin resistant L. monocytogenes, resulting in 8 log CFU/egg. Following air drying, hard-boiled eggs were treated at 5 or 25°C with 2% acetic, lactic, or malic acid. L monocytogenes populations were enumerated in intervals up to 24h by homogenization of HBEs with BLEB and cultivation on BHIrif. For pre- treatment storage trials, HBEs were first dip- inoculated with a rifampicin- resistant 4- strain L. monocytogenes cocktail for 20 min, resulting in 1 log CFU/egg, air dried for 10 min, followed by treatment with 2% acetic, lactic, or malic acid for 24 h at either 5 or 25°C. For post- treatment inoculation trials, HBEs were first soaked in 2% acetic, lactic, or malic acid for 24 h at either 5 or 25°C, air dried for 10 min, spot-inoculated at 1 log CFU/egg, and then dried for 20 min. All HBEs were individually stored in bags at 5°C for up to 28 days. The presence of L. monocytogenes was determined at intervals during storage by enrichment with BLEB on BHIrif and Brilliance Listeria Agar. Triplicate eggs were assessed for each timepoint, and three independent trials were conducted. Data were analyzed by Student’s T-test, ANOVA, and Fisher’s exact test, p≤0.05. The initial inoculation level of L. monocytogenes on HBEs was 8.27±0.37 log CFU/egg. After 24 h treatment, all L. monocytogenes populations were significantly reduced on HBEs. At 5°C, populations were reduced by 3.15±0.70, 3.46±0.02, and 4.78±0.23 log CFU/egg. Compared to 5°C, a significantly higher population reduction occurred with acetic and lactic acid when treatment occurred at 25°C. The inactivation of L. monocytogenes on HBEs for the storage trials was associated with the order of the contamination: pre-or post-the acid treatment. Prior storage, L. monocytogenes was detected on 100% of the HBEs. Malic acid pre-treatment was significantly effective in eliminating L. monocytogenes on HBEs at 5 and 25°C, while acetic acid was effective only at 5°C. All acids did not eliminate L. monocytogenes in the case of post-treatment contamination at any tested temperature. The results of this study aid in understanding the efficacy of organic acid treatments against L. monocytogenes on HBEs. Results are useful in the development of preventive controls and guidelines to ensure the safety of HBEs.
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Title: ANALYTICAL APPROACH TO ESTIMATE ROTOR TEMPERATURE IN SWITCHED RELUCTANCE MOTOR
Creator: Koujalagi, Shweta Manohar
Date: 2022
Description: Motors contribute most of the loads. Motors find major applications in automobile industries, household appliances, industrial equipment, and...
Show moreMotors contribute most of the loads. Motors find major applications in automobile industries, household appliances, industrial equipment, and other areas. With the time, engineers and industries found some of the drawbacks or disadvantages of using induction motors in certain applications. They started developing other types of motors that are more efficient than existing ones. Among those, switched reluctance motor, referred as SRM is the one. SRMs are simple in construction, rugged and highly efficient motors.Even though SRM has higher efficiency, it still contribute some losses in the form of heat which will increase the temperature of SRM. If the temperature increases beyond certain limit, cable insulation fails, degrades rotor capability of aligning characteristics, damages bearings, etc. Therefore, it is important to understand the flow of heat in SRM. This thesis focuses on heat transfer analysis from stator coil to rotor of SRM using analytical method and numerical method such as finite element analysis from available coil temperature without using any kind of sensors. Analytical and FEA models are built separately to obtained rotor temperatures at various coil temperatures and rotor speeds. Finally, analytical results are validated with FEA model results. Therefore, once the rotor temperature is estimated accurately, model can be implemented in automotive and other industrial applications to continuously monitor the rotor temperature. It is important to monitor temperature to avoid damage of SRM by thermal effects.
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Title: THE RELATIONSHIP BETWEEN SLUGGISH COGNITIVE TEMPO AND PERFORMANCE ON TASKS OF PROCESSING SPEED: INFLUENCE OF DEPRESSION
Creator: Kim, Jeong Hye
Date: 2021
Description: Sluggish cognitive tempo (SCT) is often associated with reported difficulties in various functional areas, including daily activities,...
Show moreSluggish cognitive tempo (SCT) is often associated with reported difficulties in various functional areas, including daily activities, emotional functioning, cognitive functioning, academic performance, and sleep. However, there are only a handful of research studies on SCT and neurocognitive functioning in adult populations, and the neuropsychological profile of SCT in adults is unclear.The purpose of this research is to investigate the effect of depression on the relationship between a self-reported measure of SCT and objective measures of SCT in adults by focusing on processing speed performance. The result of this research supports the previous notion that SCT is a novel and independent condition distinct from ADHD, and there are significantly positive relationships between symptoms of SCT and Inattention and Hyperactivity/Impulsivity. Furthermore, SCT and depression are also positively associated indicating the people who experience more symptoms of SCT report more symptoms of depression. However, results did not support the hypothesis that SCT significantly contribute to differences in performance on various types of neuropsychological tasks (WAIS PSI, Trail Making Test, and CPT-II Reaction Time) assessing processing speed after controlling for symptoms of ADHD (inattention and hyperactivity/impulsivity) and symptoms of depression. It is notable that the significant model beta weights for SCT in the final regression model suggests that the relationship between SCT and processing speed is worthy of additional investigation.
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Title: MULTICRITERIA DECISION-MAKING METHODOLOGY WITH TRADEOFF ANALYSIS FOR TRANSPORTATION BUDGET ALLOCATION
Creator: Truong, Tung Quoc
Date: 2022
Description: Transportation agencies in the United States nowadays rely on tax dollars for maintaining surface transportation infrastructure, which mainly...
Show moreTransportation agencies in the United States nowadays rely on tax dollars for maintaining surface transportation infrastructure, which mainly comes from fuel tax. However, travel behaviors are changing every day. People and businesses demand better and safer roads. Yet, consumers travel in more fuel-efficient vehicles and buy less gas, which means less revenue for fixing aging roads and highways. Meanwhile, new construction and repair costs increase for our overburdened transportation systems. Transportation agencies, therefore, must use their limited funding more wisely to optimize the service performance and minimize risks (Li, 2018). The budget allocation problem in transportation is not an easy task. The consequences of an ineffective decision in allocating resources are multi-facet both in the short- and long-term, including degrading in the condition of transportation facilities, losing public trust, and increasing backlogs in maintenance and repair. Therefore, transportation agencies are seeking more robust and comprehensive data-driven strategies that take into account of agency’s strategic goals and regulatory requirements, user expectations, nature of the asset, availability of resources, and lifecycle cost analysis in determining the optimal allocation of resources and making the best use of available funds (Li and Sinha, 2004; Sinha and Labi, 2007). The proposed research aims to utilize the concept of multicriteria decision making coupled with a holistic asset management framework to support performance-based allocations of transportation budgets and help transportation agencies achieve the future vision of the nation’s strategic planning requirements to enable sustainable management of the system. A computational study for the real-world dataset obtained by a state Department of Transportation (DOT) is conducted using the proposed budget allocation method. The results from the computational study reveal that the proposed method can derive optimal decision solutions for transportation budget allocation problems and can be utilized by transportation agencies on different scales – urban and rural, in other sectors – public and private, to effectively manage the transportation infrastructure sustainably, by effectively spending transportation budget to maximize service performance and minimize operating costs.
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Title: CARING FOR THE CAREGIVER: INTERPERSONAL FACTORS AND DEPRESSION AS PARALLEL-SERIAL MEDIATORS BETWEEN STIGMA AND SUICIDAL IDEATION
Creator: Tsen, Jonathan Y.
Date: 2022
Description: Background/Objectives: This study applied Joiner's Interpersonal PsychologicalTheory to a caregiver population, by describing relationships...
Show moreBackground/Objectives: This study applied Joiner's Interpersonal PsychologicalTheory to a caregiver population, by describing relationships among affiliate stigma, thwarted-belongingess (TB), perceived-burdensomeness (PB), and depression, and suicidal ideation (SI). Participants/Setting: 243 adult caregivers participated in this study via Prolific Academic and caregiver-related websites. Design/Main Outcome Measures: This study used a cross-sectional, survey-based design including demographics, the Affiliate Stigma Scale (α=.93), Interpersonal Needs Questionnaire-15 (α=.95), Center of Epidemiology Studies–Depression-10 (α=.90), and Depressive Symptom Inventory— Suicide Subscale (α = .91) via Qualtrics. Analyses run on SPSSv27/Hayes’ PROCESS macro. Results: Parallel-serial mediation found after controlling for covariates that the total indirect effect of affiliate stigma on SI through both TB and PB then through depression was significant, B = .0271, SE = .0062, β = .1659, 95%CI [.0152, .0393]. Conclusions: Findings indicated that affiliate stigma indirectly affected SI through both TB and PB then through depression. Interventions to improve caregiver wellbeing should capitalize on both improving interpersonal functioning and depressive symptoms in tandem in order to reduce SI risk.
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Title: Towards Understanding the Microstructure and Mechanical Properties of Additively Manufactured Ni-base Superalloys
Creator: Tiparti, Dhruv Reddy
Date: 2022
Description: Nickel-base superalloy components such as turbine discs typically undergo numerous manufacturing steps that contribute to increasing the cost...
Show moreNickel-base superalloy components such as turbine discs typically undergo numerous manufacturing steps that contribute to increasing the cost and the waste of excess materials. With advent of fusion based additive of manufacturing (AM) techniques, such components with complex geometry can be fabricated with great efficiency. However due to characteristically high energy densities, fast cooling rate, and layer-by-layer building process associated with AM; Ni-base superalloys with higher temperature performance are difficult to be fabricated by AM due to susceptibility to composition related defect formation, which is further exacerbated by anisotropic grain structures induced by the large thermal gradients present. Crack-free material can be fabricated but, in most cases, issues such as an anisotropic microstructure will prevail, and the balance of mechanical properties achieved may not be suitable for the desired applications. Several strategies exist to mitigate the challenges posed by additive manufacturing via post-processing such as hot-isostatic processing, annealing heat treatments, application of grain refining inoculants, etc. All these strategies utilized to mitigate issues with AM of Ni-base superalloys still require further study to understand their effects on the microstructure and mechanical properties. This work aims to evaluate the use of inoculant particles, and novel heat treatments on the microstructure and mechanical properties of different superalloys. First, the effect of varying amounts of CoAl2O4 inoculant ranging from 0 to 2 wt.% on the microstructure evolution of Inconel 718(IN718) fabricated by selective laser melting (SLM) was evaluated. The findings from this study indicated that additions of CoAl2O4 only resulted in a minor degree of grain refinement with slight increase in anisotropy; in addition, a CoAl2O4 ¬content above 0.2 wt.% resulted in the formation of agglomerate inclusions; and that to effectively utilize CoAl2O4 as a grain refining inoculant, process parameters must be further optimized while considering the formation of agglomerates, and other defects. Second, the application of CoAl2¬O4 was extended towards the Direct Energy Deposition (DED) of IN718. Here findings indicated that due to the modification of the thermophysical properties of the melt pool by oxide addition, an earlier onset of large columnar extending across multiple layers occurred while counteracting conditions required for equiaxed grain formation; and these CoAl2O4 were also found to exhibit a potent Zenner pinning effect that maintained the as-built grain structure despite application of extreme high treatment condition of 1200oC for 4 hrs. Third, the tensile and fatigue properties of the DED IN718 with CoAl2O4 were evaluated. Here, it was found that the addition of CoAl2O4 leads to a minor increase in tensile strength in the as-built condition attributed primarily to the fine oxide dispersion; a more modest increase in tensile strength in the heat-treated condition due to grain refinement induced by retaining the as-built grain structure; and that despite the increase in tensile strength with CoAl2O4 a corresponding increase in fatigue life did not occur. Lastly, the processing of René 65 conducted by laser-powder bed fusion(L-PBF) was done and compared to the conventionally cast and wrought material. Here, the effect of the difference in processing route in conjunction with heat treatments was evaluated to understand the creep and stress relaxation behavior. It was found that L-PBF of René 65 led to an overall improved resistance to deformation by creep and relaxation mechanism.
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Title: SYNTHESIS AND CHARACTERIZATION OF MG, NB, TI-DOPED LINIO2 CATHODE MATERIAL FOR LI-ION BATTERIES
Creator: Tian, Yiwen
Date: 2022
Description: In this project, the influence of several metal doping on the electrochemical properties of LiNiO2 materials was analyzed. The doping method...
Show moreIn this project, the influence of several metal doping on the electrochemical properties of LiNiO2 materials was analyzed. The doping method is aiming to improve the stability of the layered structure and inhibit the mixing of nickel and lithium by enhancing the structural stability of the layered material and replacing part of Ni with other metals in the process of intercalation/deintercalation, thereby promoting the cyclic performance and reversible capacity. The LiNiO2 powder doped with Nb, Ti and Mg is denoted as Li0.96Ni0.9Nb0.06Ti0.04Mg0.02O2 or, in short, metal-doped LiNiO2. The synthesis of the metal-doped LiNiO2 powder consists of mixing the lithium and nickel sources with various metal oxides and then being subjected to high-energy ball milling for 10 hours, followed by heating for 20 h in a metallic tube furnace at 680℃ with flowing oxygen atmosphere. The undoped LiNiO2 powder synthesized using the same process and conditions was compared with the doped LiNiO2 powder. In order to understand the doping mechanism, field emission scanning electron microscopy (FESEM), energy dispersive spectroscopy (EDS), and X-ray diffraction (XRD) were used to analyze the morphology, composition and crystal structure of the final product. Benefiting from the Mg, Nb, and Ti doping, the doped LiNiO2 exhibited a high reversible capacity of 130.56 mAh g-1, higher than that of undoped LiNiO2 (95.02 mAh g-1) under the 0.1C charge/discharge rate in the voltage window between 2.5 and 4.2 V. Further, the doped LiNiO2 has 86% of capacity retention over 100 cycles, better than undoped LiNiO2 (only 44% of capacity retention) under the 0.5C charge/discharge rate between 2.5 and 4.2 V.
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Title: Quality of Life in People with Epilepsy: The Associations of Anti-seizure Medications and Biopsychosocial Variables
Creator: Thomas, Julia A.
Date: 2022
Description: People with epilepsy, on average, experience lower quality of life (QOL) than healthy controls (Taylor et al., 2011). This study examined the...
Show morePeople with epilepsy, on average, experience lower quality of life (QOL) than healthy controls (Taylor et al., 2011). This study examined the associations between specific anti-seizure medication, biopsychosocial factors, and QOL in people with epilepsy. Analysis of covariance revealed that individuals taking three or more anti-seizure medications had significantly lower QOL than those taking levetiracetam. Findings also demonstrated that when looking at biopsychosocial factors as predictors of QOL in hierarchical regression, anxiety, depression, and daytime sleepiness were significant predictors of QOL. Once these factors were entered into the model, number of medications was no longer significant. The final model predicted 59.6% of the variance in QOL. Lastly, a moderation analysis to examine the moderating effect of employment on the association between number of anti-seizure medications and QOL was not significant. Additional exploratory analyses looking at individuals who were employed versus those who were not employed were completed. These findings underscore the importance of addressing psychological health and sleep factors within the epilepsy population.
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