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Title: Transdiagnostic Emotional Factors as Mediators of the Relation between Obsessive-Compulsive Symptoms and Tobacco Use and Dependence in a Large Community Sample of Adolescents
Creator: Chang, Weilynn Christine
Date: 2023
Description: This study investigated the associations between obsessive compulsive disorder symptoms (OCS) and tobacco use and tobacco dependence in a...
Show moreThis study investigated the associations between obsessive compulsive disorder symptoms (OCS) and tobacco use and tobacco dependence in a large community sample of adolescents. Specifically, transdiagnostic emotional vulnerability factors (i.e., anhedonia, distress tolerance and anxiety sensitivity) were explored as potential mediators of the relation between OCS and tobacco use/dependence. Weighted logistic regression models found that OCS was significantly positively associated with likelihood of tobacco use in the past six months (when suppressor variables were excluded). Similarly, zero-inflated negative binomial regression models found a significant positive relation between OCS and tobacco dependence (when suppressor variables were excluded). There was no significant weighted indirect effect via anhedonia for the OCS-Tobacco Use association, which suggests that anhedonia was not a significant mediator in this case. However, the indirect effect via anhedonia for the OCS-Tobacco Dependence association was significant at the p < .05 level, but not the adjusted p < .001 threshold (when suppressor variables were removed). The weighted indirect effect via distress tolerance for the OCS-Tobacco Use association was significant at the p < .05 level, but not the p < .001 threshold (when suppressor variables were removed). There was no significant indirect effect via distress tolerance for the OCS-Tobacco Dependence association. There was a significant weighted indirect effect via anxiety sensitivity for the OCS-Tobacco Use association (when suppressor variables were removed). There were no significant indirect effects via anxiety sensitivity for the OCS-Tobacco Dependence association. When overlapping variance was accounted for by including all three mediators simultaneously, anhedonia was still not a significant mediator of the OCS-Tobacco Use association; there were still significant indirect effects via distress tolerance and anxiety sensitivity, under specific model parameters. Our results also revealed that while Asian adolescents demonstrated lower likelihood of tobacco use compared to those who were Hispanic/Latinae, Asian youth demonstrated more severe tobacco dependence symptoms.
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Title: The Peter Principle and Career Development in Construction Management
Creator: Bolisetty, Lakshmi Satya Bavya
Date: 2023
Description: The construction industry, like any other industry, may benefit from updating its working environment by adopting advances in technology,...
Show moreThe construction industry, like any other industry, may benefit from updating its working environment by adopting advances in technology, updating the qualifications of its workforce, and ensuring that the right professionals are employed at each level. Having effective career development programs, filling project management roles with competent professionals, and promoting competent professionals ensures a successful project delivery. Promotion typically ensures candidates are rewarded for their performance and motivates them towards achieving higher success. Promoting the wrong person or having an incompetent person at any management level has detrimental effects to the project’s success. However, according to the “Peter Principle” (Peter, 1969), incumbents in a hierarchy tend to rise to “a level of respective incompetence”. That is, they are promoted based on their success in their current role, rather than their ability to perform in the new one. Through a review of the literature and a critical analysis of the existing research, this study examines the strengths and weaknesses of the Peter Principle and its relevance to professionals employed by construction companies and construction management firms in contemporary management practice. It also explores the reasons why an incumbent is stuck in a position for a long time. The findings of this research suggest that while the Peter Principle may have some limitations, it remains an important concept for managers to consider when making decisions about employee promotion and development. It concludes that while the Peter Principle may have a significant effect in promotion decisions, there are also external circumstances unique to each individual that may affect their performance.
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Title: Organo-Functionalized Polyoxometalates
Creator: Alsaleh, Musaed Riyadh A
Date: 2023
Description: Polyoxometalates (POM) or transition metal oxide clusters are a sub-class of metal oxide-based materials of contemporary interest. POMs are...
Show morePolyoxometalates (POM) or transition metal oxide clusters are a sub-class of metal oxide-based materials of contemporary interest. POMs are molecular systems which contain highly symmetrical structures and are characteristics of group 5 and 6 metals, especially V, Mo, and W. Typical POM clusters have nuclearities ranging from 6 to 18 metal centers and are purely inorganic in their compositions. POMs can act as multielectron redox systems, while retaining their robust oxometallic framework structure. POMs have been receiving increasing attention, in part due to their potential as redox active materials for applications in various areas and their suitability as attractive molecular building units for making new functional materials of desirable properties and functions.In recent years, there has been a growing interest in the functionalization of polyoxometalates with organic moieties to synthesize organo-functionalized POMs. During the course of the work described in this thesis, we explored the synthesis of organo-functionalized polyoxometalates with special interest in polyoxovanadates incorporating heterometal center(s) in addition to vanadium in the structure. The focus of the work was on low nuclearity POMs. The thesis describes the synthesis and full characterization of a new organo-functionalized polyoxovanadate cluster - [(n-C4H9)4N]2[V6O13{(OCH2)3C (CH2CH3)}2]. The cluster compound has been characterized by a series of analytical techniques- FT-IR, Thermo Gravimetric Analysis, Bond Valence Sum calculations and complete single X-ray diffraction structure analysis. The hexavanadate cluster features {V6O19} oxometallate core composed of six edge sharing {VO6} octahedra defined by five bridging oxygen atoms and a terminal {V=Ot} oxo group. The {V6O19} oxometallic core of the cluster adopts the Lindqvist structure incorporating two 1,1,1-tris(hydroxymethyl)propane organic ligands. Six of the oxygens in the {V6O19} core come from the three alkoxy groups from two organic ligands. To the best of our knowledge, this organo-functionalized POM cluster has not been reported in the literature previously.
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Title: Efficacy of Power Ultrasound Technology on the Reduction of Listeria monocytogenes and Salmonella enterica on Produce Matrices
Creator: Biswas, Priya
Date: 2023
Description: Fresh produces are considered as ready-to-eat (RTE) and are minimally processed before the distribution to retailers and consumers. Fresh...
Show moreFresh produces are considered as ready-to-eat (RTE) and are minimally processed before the distribution to retailers and consumers. Fresh produce recalls are frequently linked with pathogenic bacteria like Salmonella enterica and Listeria monocytogenes because of minimal processing. This study evaluated the use of power ultrasound coupled with organic acids like citric, acetic, and lactic acid which are generally recognized as safe and often helps to maintain the quality and prolong the shelf life of fresh RTE fruits and vegetables.All the produce matrices which include cucumbers, romaine lettuce, tomatoes, and strawberry were inoculated with four-strain cocktails of rifampicin-resistant S. enterica or L. monocytogenes at approximately 8 log CFU/ matrix. The produce matrices were dried for 1 h and treated for 2 minutes using 2 % or 5 % citric, lactic, or malic acid. This treatment was conducted with or without power ultrasound treatment at 40 kHz. Samples were taken in sets of three and placed into a stomacher bags. The bag contained 225 ml of water or acid. Following a 2 min treatment period, the samples were placed in separate stomacher bags, each containing 225ml of BPB or BLEB, for S. enterica or L. monocytogenes respectively. Followed serial dilutions, samples were then plated on BHIARif plates. For each condition, triplicate samples were taken, and three separate trials were conducted. The use of Student's t-test allowed for the evaluation of population differences, with a significance level of p<0.05 being deemed significant. Cucumber, romaine lettuce, tomatoes, and strawberries treated with 5 % concentration of citric, lactic, and malic acids, with addition of ultrasound showed a greater result in reductions of S. enterica to populations of 5.54 ± 0.47, 4.54 ± 0.83, and 4.69 ± x 0.36, log CFU/cucumber, 6.66 ± 0.51, 4.12 ± 0.32, and 5.51 ± 0.68, log CFU/ lettuce, 4.38 ± 0. 47, 3.12, and 5.04 ± 0.37 log CFU/ tomato, 4.66 ± 0.49, 4.69 ± 0.06, and 6.22 ± 0.39, log CFU/ strawberries, respectively. For L. monocytogenes, 5 % concentration of acids with the addition of ultrasound resulted in populations of 7.69 ± 0.35, 6.04 ± 0.24, and 6.96 ± 0.41, log CFU/ cucumbers, 7.57 ± 0.12, 5.49 ± 0.55, and 5.78 ± 0.73 log CFU/ lettuce, 6.44 ± 0.13, 5.08 ± 0.12, and 6.04 ± 0.22 log CFU/ tomato, 6.16 ± 0.37, 5.18 ± 0.22, and 5.64 ± 0.50, log CFU/ strawberries, respectively. The most effective acid was lactic when compared with citric and malic acids. The objective of this study is to investigate the effectiveness of power ultrasound as a novel non-thermal processing technology, in order to contribute to the existing knowledge base on this topic.
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Title: Critical Understanding of Multi-Mode Luminescence Properties of Eu3+ Doped LaAlO3
Creator: Alolayan, Abdulelah Abdulaziz H
Date: 2023
Description: Fluorescent anti-counterfeit materials with multi-luminescent modes under different external excitation sources are always advantageous over...
Show moreFluorescent anti-counterfeit materials with multi-luminescent modes under different external excitation sources are always advantageous over the conventional anti-counterfeit techniques. In the present thesis, our aim is to develop efficient Eu3+ doped LaAlO3 phosphor materials with different modes of luminescence properties such as down conversion-luminescence (DCL), persistent-luminescence (PersL), and optically stimulated luminescence (OSL), Thermo-luminescence (TL), radioluminescence (RL) Although, there are many reports on persistent-luminescence and optically stimulated luminescence based on Eu3+ doped matrices but the red persistent luminescence of Eu3+ ion on those matrices is not very long and the OSL intensities are also low. Herein, we report a long red persistent luminescence which lasted for 17 hrs. and the OSL intensity is very high. Furthermore, we have observed that the OSL property can be achieved even after 35 days of UV excitation and indicating its potential application for optical storage phosphor. From carrying out TSL studies we have found that three different types of traps namely Trap 1, Trap 2 and Trap 3 with trap depth 0.63 eV, 0.82 eV, 1.02 eV respectively are responsible for the persistent and OSL properties. It has been concluded that Trap 1 is mostly responsible for the persistent luminescence in short term while Trap 2 and Trap 3 are responsible for intermediate and long persistent luminescence. Further, Trap 2 and Trap 3 were also found to be present even after 35 days and responsible for the OSL properties. Anti-counterfeiting PersL composite has been developed in which AC real-life application is demonstrated.
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Title: Neuropsychological Pattern of Verbal and Nonverbal Processing Speed Discrepancy in Veterans with Co-Occurring mTBI and PTSD
Creator: VanLandingham, Hannah B.
Date: 2023
Description: Rates of traumatic brain injury (TBI) exposure have increased over time (CDC, 2022). This pattern of increased TBI risk is additionally...
Show moreRates of traumatic brain injury (TBI) exposure have increased over time (CDC, 2022). This pattern of increased TBI risk is additionally associated with risk for development of posttraumatic stress disorder (PTSD; APA, 2013). Ongoing PTSD symptomology can lead to neuropsychological profiles in which deficits are more pronounced for verbally constrained performances when compared to nonverbal performances. However, less is known about this performance discrepancy in patients with a history of head injury with comorbid PTSD. Moreover, the little existing research focuses on the domains of executive functioning, learning, and memory, with little to no research on processing speed discrepancies. These findings could have significant implications for healthcare and cognitive intervention pre- and post-mTBI and/or trauma exposure because this discrepancy may impact clinical assessment and subsequent diagnosis. The analysis will include 1) determination of statistically and clinically significant differences for those with co-occurring PTSD and mTBI, and 2) examine within-subjects differences with and without the inclusion of covariates. The present research found that there are no differences between those with co-occurring PTSD and head injury compared to individuals without a co-occurring diagnosis, in addition to no significant discrepancies notes within the PTSD and mTBI group alone
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Title: Modeling and Optimization of Power Plant Cooling Tower Systems Using Physics-Based and Neural-Network-Based Models
Creator: Salomon, Basile Clément Paul
Date: 2023
Description: Condensers and cooling towers are commonly used in steam power plants to condense the steam exiting the turbine and to recycle the condensed...
Show moreCondensers and cooling towers are commonly used in steam power plants to condense the steam exiting the turbine and to recycle the condensed-water into the boiler in a closed-loop system. These condensers typically use cooling water drawn from a water body (lake, river etc) to condense the steam. Cooling towers are used to lower the temperature of the warm water exiting the condenser. Since the steam condensation temperature plays an important role in the power plant efficiency, cool- ing tower performance which is limited by the wet-bulb temperature of the ambient air has been extensively studied. This work investigates the modeling of an enhanced cooling tower technology using a new pre-cooling and dehumidifying system (PDHS). This new system, based on a reversed Brayton cycle, is made out of a compressor, an air-cooled heat exchanger (HX), a heat and mass exchanger (HMX) and an expander. The goal of this PDHS concept is to pre-cool the air entering the cooling tower in order to improve its performance. In this work, a systems model has been developed. Thermodynamic models have been used for the compressor, the air-cooled heat exchanger and the expander. For the remaining components, i.e. the heat and mass exchanger, the cooling tower and the condenser, physics-based models have been developed and tested. Once tested and validated, each model can be integrated into the integrated PDHS-cooling tower-condenser system. Two different configurations of the PDHS have been considered in this thesis. In the open water loop configuration, the water in the HMX is obtained from the municipal water supply (or an alternate water source) and is released back to the source after exiting the HMX. In the closed water loop configuration, the water used to cool down the air in the HMX is being recirculated and cooled in the power plant cooling tower. The physics-based model of the PDHS developed in this work has been validated using results from an empirical model of the PDHS by GTI Energy. This first case study also shows how the PDHS can be used to save water in the cooling tower (CT). Indeed, when using the PDHS, a 37% reduction in the cooling tower evaporation rate can be observed when comparing to the baseline. This decrease in the CT evaporation rate is the main source of make-up water savings. Moreover, the water harvested by condensation in the PDHS can be redirected towards the CT, bringing another source of water savings. These two combined lead to an overall 46% decrease of the make-up water usage in the cooling tower. Another case study has been conducted on a 500 MW condenser unit. It shows that, under summer ambient conditions i.e. Ta,db = 35°C and φ = 47%, the PDHS can help the condenser restore its designed cooling load of 453 MW. Finally, using the physics-based model to create a dataset, an artificial neural network model of the PDHS has been developed to constitute a black box for the PDHS that would be able to predict with sufficient accuracy the condenser and HMX loads, the air conditions at the inlet of the CT and water temperature at both ends of the condenser and CT given the ambient air condition, the compressor pressure ratio and the water split between the condenser and the heat and mass exchanger.
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Title: Functionalized 2D Materials as Enablers of High Energy and High Power Energy Storage Devices
Creator: Radhakrishnan, Sivaviswa
Date: 2023
Description: The present Thesis concerns with the synthesis of novel functionalized 2D materials for applications as cathodes in lithium-ion batteries. It...
Show moreThe present Thesis concerns with the synthesis of novel functionalized 2D materials for applications as cathodes in lithium-ion batteries. It further concerns with the role of porosity in these novel cathode materials to achieve simultaneously high energy and power density. Examples of the novel cathode materials synthesized here include several functionalized hexagonal boron nitride (hBN) and graphene (G) species. hBN was functionalized with Li₂C₂O₄, LiBF₄, -OBF₂ groups, NOBF₄, etc. The color of the functionalized hBN species ranges from white through brown to black indicating drastic changes in the band structure of hBN due to functionalization. Functionalized G species include Li₂C₂O₄ and -OBF₃ functionalized ones. Preliminary electrochemical tests were carried out for an initial assessment of the properties of these materials. Additionally, the role of the DOL solvent was also investigated in high power CFx batteries
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Title: Design and Fabrication of Battery-Operated Radiator Control (BORC) Utilizing 3D Printing Strategies
Creator: Riley, Christopher W.
Date: 2023
Description: The scope of this work aims to serve as a continuation of prior research focused on the “development and evaluation of an automatic steam...
Show moreThe scope of this work aims to serve as a continuation of prior research focused on the “development and evaluation of an automatic steam radiator control system or retrofitting legacy heating systems in existing buildings” (Syed Ali et al., 2020) by describing and testing the mechanical components of the developed controller in full detail. Other aspects of radiator efficiency are also explored. Primarily, this work aims to elaborate on the importance of material selection and mechanical properties of the design process. It also proposes initiative-taking solutions for the building’s energy recovery by monitoring the initial set up and focusing on certain details such as cardinal direction, thermal breaks, etc. These legacy systems are generally problematic when attempting to calculate energy efficiency, as a majority of radiator controls tend to be manual. Though there are comparable products within the European market, they cater to hot water systems and not steam, and in some instances require an internet bridge for operation (Tahersima et al., 2010). Since this is an extension of our earlier project, I will refer to it as Battery Operated Radiator Control (BORC) and the previous version as BERG’s Automated Radiator Control (ARC).
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Title: The Effect of Time Step on HSPF Model Performance
Creator: Rubinstein, Benjamin J.
Date: 2023
Description: Hydrological modeling is a mature and well researched field; however, because most climate data are collected on hour or greater time...
Show moreHydrological modeling is a mature and well researched field; however, because most climate data are collected on hour or greater time intervals there is very little research on the effect of using high resolution data as inputs for the models. A Python tool for downloading high resolution five minute interval data from the Oklahoma Mesonet was created and the PyHSPF Python package was used to generate, calibrate, and validate HSPF models using five minute, one hour, and daily time steps. Flow errors, R², and Nash-Sutcliffe efficiency for simulated outflows, and resource usage were compared for each model. The hourly and five minute models performed similarly well, and the daily model performed significantly worse. The results of this work could prove useful for policy makers and researchers looking to update or create new climate data collection protocols, and the tools used can be applied to many different kinds of future research.
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Title: Understanding Location Bias in Fake News Datasets of Twitter
Creator: Patil, Kayenat Kailas
Date: 2023
Description: Fake news tends to spread faster and wider than real news. It has a greater impact and can lead to negative and dangerous outcomes. With the...
Show moreFake news tends to spread faster and wider than real news. It has a greater impact and can lead to negative and dangerous outcomes. With the world spending an increasing amount of time on their mobile devices, people tend to get more of their news from their desired social media platform. It has become part of our daily lives, whether it is to keep in touch with friends and family, to getting gossip on celebrities or even shopping. In 2022, the average time a person spends per day on the internet on a social media platform has been accounted to be about 147 minutes,[1] indicating an increase in time spent scrolling through information online.It has become a widespread phenomenon in recent years, thanks in part to the rapid spread of information through social media and other online channels. It is increasingly important to explore and understand fake news and its impact on society, as well as to develop effective tools and methods for detecting and combating it. There are several factors that can tamper with the successful detection of fake news. Machine learning models often fall to such biases that result in inaccurate predictions. There are several biases that have been identified like age, gender, sex and many more. In this thesis, we are exploring location as a form of a bias and if it hinders prediction. We have looked at location from two perspectives. One, taking location as co-ordinates in the form of latitude and longitude and analyzing the likelihood of a tweet coming from a location to be fake or not. The second method we have used is that we have considered location as an entity and used natural language processing model to see if its able to predict if the given tweet is fake or not, along with masking the location mentioned in the tweet and analyzing how the performance of the model changes. Machine learning models can play an important role in fake news detection models, by analyzing large amounts of data and identifying patterns and indicators that suggest a piece of information may be false or misleading, but they are often susceptible to some form of biases. By studying biases on machine learning models on fake news datasets, we can develop more effective tools for identifying fake news and taking steps towards mitigating it, ultimately helping to protect the integrity of information and promote informed decision-making in society.
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Title: Effect of Pre-Processing Data on Fairness and Fairness Debugging using GOPHER
Creator: Sarkar, Mousam
Date: 2023
Description: At present, Artificial intelligence has been contributing to the decision-making process heavily. Bias in machine learning models has existed...
Show moreAt present, Artificial intelligence has been contributing to the decision-making process heavily. Bias in machine learning models has existed throughout and present studies’ direct usage of eXplainable Artificial Intelligence (XAI) approaches to identify and study bias. To solve the problem of locating bias and then mitigating it has been achieved by Gopher [1]. It generates interpretable top-k explanations for the unfairness of the model and it also identifies subsets of training data that are the root cause of this unfair behavior. We utilize this system to study the effect of pre-processing on bias through provenance. The concept of data lineage through tagging of data points during and after the pre-processing stage is implemented. Our methodology and results provide a useful point of reference for studying the relation of pre-processing data with the unfairness of the machine learning model.
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Title: Linear Systems Analysis of Molecular Dynamics
Creator: Nicholson, Stanley Anselm
Date: 2023
Description: Most proteins reduce the complexity of atomic motion to stable and coherent structures. Molecular dynamics (MD) has provided swaths of...
Show moreMost proteins reduce the complexity of atomic motion to stable and coherent structures. Molecular dynamics (MD) has provided swaths of trajectory data of proteins. We analyze these trajectories using classical stochastic signal analysis, well established and utilized by engineers. Linear systems analysis operates to uncover linearities given an input and output signal. The coherence function says an input and output are linearly related if and only if the coherence equals one. Analyzing protein motion in the frequency domain allows us to extract a frequency function relating the modes of motion as determined by atomic power spectra. Motivated by biochemistry, we analyze classical interactions like hydrogen bonds and salt bridges and find they act like a linear system, or effective spring. We test our analysis on two protein systems: crambin and the Mu Opioid Receptor (MOR). We extend our results to all pairwise interaction and determine coherent communities of atoms within the MOR. We present various community detection algorithms and demonstrate their validity using common metrics in MD. Identifying rigid and tightly correlated regions of the protein offers great potential in coarse graining protein structure and understanding protein motion.
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Title: Pain and Life Satisfaction: The Role of Emotional Support and Social Participation in Adults with Pediatric-Onset Spinal Cord Injury
Creator: Oh, Alison J.
Date: 2023
Description: Individuals who acquire a spinal cord injury (SCI) during their pediatric years are unique from individuals who acquire an SCI during...
Show moreIndividuals who acquire a spinal cord injury (SCI) during their pediatric years are unique from individuals who acquire an SCI during adulthood due to the heightened risks for developing secondary health conditions and chronic pain. These concerns may significantly impede developmental milestones and experiences, such as social participation, that may decrease life satisfaction. Thus, research on pain characteristics (e.g., frequency of pain, duration of pain, level of current pain, and level of general pain) alongside the role of emotional support and social participation on life satisfaction in adults with pediatric-onset SCI is needed. This study sample consisted of 205 individuals with pediatric-onset SCI who were former patients at pediatric hospitals in three metropolitan cities. Participants were individuals who were 19 years of age or older at the time of the interview, with the age of injury at 18 years or prior. Associations between demographic, pain, and injury characteristics, emotional support, social participation, and life satisfaction were assessed via bivariate Pearson correlations and a 3-block hierarchical multiple linear regression with LS as the primary outcome. Although pain characteristics and emotional support were not associated with life satisfaction among adults who sustained a pediatric-onset SCI, social participation was positively associated with life satisfaction. These findings suggest that clinicians should evaluate various pain characteristics and highlight the role of social participation when treating individuals with SCI.
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Title: Examination of Power Ultrasound and Organic Acid-based Hurdle Technology in the Reduction of Salmonella Enterica on Peaches and Apples
Creator: Mathias, Hina Valida
Date: 2023
Description: Fresh produce includes fruit matrices like whole peaches and apples that are minimally processed and are a popular choice among different...
Show moreFresh produce includes fruit matrices like whole peaches and apples that are minimally processed and are a popular choice among different types of demographics because of their nutrition content and health benefits. However, there have been increasing pathogen outbreaks in these matrices over the past few decades, which are majorly rooted in cross contamination either due to poor handling pre and post processing or the insufficient reduction of the pathogen at processing by the applied hurdle technology. While chemical sanitizers are a popular option in the food industry, the awareness and demand for green consumerism and sustainability have created a need for research to determine the efficacies of organic acids and non-thermal technologies like power ultrasound in the reduction of different pathogens on different food matrices. This study focusses on the S. enterica reduction capabilities of three organic acids – citric, malic, and lactic alone and in combination with 40 kHz power ultrasound at 1, 2 and 5% for treatment times of 2, 5 and 10 min on whole yellow peaches and gala apples. Peaches and apples were spot inoculated with a four-strain cocktail of S. enterica, resulting in 9 log CFU/fruit. Post air drying for 1 h, the fruits were treated with water, 1, 2, or 5% citric, lactic, or malic acid for 2, 5 or 10 min with and without power ultrasound treatment at 40 kHz. The population of S. enterica on the fruits was enumerated before and after treatment. Three independent trials with triplicate samples were performed for each condition. Population differences were evaluated via Student's t-test and ANOVA; p<0.05 was considered significant. The initial level of inoculum ranged from 8.67 ± 0.41 to 8.20 ± 0.26 log CFU/peach and 7.28 ± 0.60 to 8.17 ± 0.37 log CFU/apple in peaches and apples, respectively. Water treatments showed pathogen reduction as high as 1.22 log CFU/peach and 1.02 log CFU/apple. Citric acid treatments on peaches showed significant pathogen reduction at higher time increments at 5% with a reduction of S. enterica as high as 2.24 log CFU/peach after 10 min. Malic acid showed the highest recorded log reduction in peaches at 5% and 10 min being 4.20 log CFU/peach (n=1/9, samples above the enumeration limit) and apples at 5% and 5 min being 3.71 log CFU/apple (n=4/9, samples above the enumeration limit) both in combination with an ultrasound. Lactic acid, unlike the other two organic acids, showed a pathogen reduction of over 3 log CFU/fruit at 2% after 10 min, with the highest pathogen reductions of 3.76 log CFU/peach and >3.62 log CFU/apple at 5% and10 min. There was no particular trend with significant enhancement of pathogen reduction either with time increment or the addition of ultrasound and varied with the varying acids, treatment conditions and fruit matrices.
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Title: Cities on the Move: Envisioning Cityscape in the Autonomous Vehicle Era
Creator: Lee, Hyo Eun
Date: 2023
Description: As cities have developed in response to a rapidly changing environment since the industrial revolution, a variety of circumstances and issues...
Show moreAs cities have developed in response to a rapidly changing environment since the industrial revolution, a variety of circumstances and issues have arisen. In cities, technological development and the rise of private automobiles have been related to urban sprawl, traffic congestion, environmental degradation, and mobility inequalities. Currently, autonomous vehicles are bringing a paradigm shift in mobility as technological innovations accompany the fourth industrial revolution. As cities undergo renewal through new mobility, recent developments in driverless technologies should be considered for their long-term impact on the built environment. The purpose of this thesis is to propose a design, along with a set of scenarios, for a transportation hub in the era of autonomous vehicles to address today's complex mobility requirements. Through bringing together existing case studies, research on autonomous vehicles, and drawing conclusions regarding the relationship between mobility and urban landscapes, this thesis explores how autonomous vehicles will affect the future built environment in a set of timelines. Considering the future transportation hub will require programs and infrastructure to support autonomous vehicles, this thesis also provides a vision of the future of transportation modes and how they interact. Finally, a transportation hub design model and an automation city model for the AV era will be proposed.
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Title: Simulation and Experimental Testing of High-Gradient Dielectric Disk Accelerating Cavities
Creator: Weatherly, Sarah K.
Date: 2022
Description: Structure-based wakefield acceleration can be accomplished using either Collinear Wakefield Acceleration (CWA) where the drive beam and the...
Show moreStructure-based wakefield acceleration can be accomplished using either Collinear Wakefield Acceleration (CWA) where the drive beam and the witness beam are located on the same beamline or Two Beam Acceleration (TBA) where the RF power generated by the drive beam is extracted and transferred to the witness beam line. A Dielectric Disk Accelerator (DDA) is an accelerating structure that is utilized by TBA that uses dielectric disks to improve the structure's shunt impedance and accelerate the witness beam. Dielectric based accelerators studied in this thesis are X-Band structures (have a working frequency between 8 and 12 GHz) that can use any pulse length but in this study utilize short (<20 ns) traveling wave pulses. Short pulse lengths are used to decrease breakdown probability and allow for a large gradient. DDAs have a higher group velocity and a larger shunt impedance compared to traditional metallic accelerating structures while maintaining a large accelerating gradient. DDAs are a strong candidate for use in the Argonne Wakefield Accelerator’s 500 MeV Demonstrator. Recent experimental results of a clamped single cell structure demonstrated a >100 MV/m accelerating gradient with no evidence of breakdown in the RF volume. Additional structures, including a brazed single cell model and a multicell structure, have been designed and are now being fabricated for high power testing.
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Title: ESTIMATING PM2.5 INFILTRATION FACTORS FROM REAL-TIME OPTICAL PARTICLE COUNTERS DEPLOYED IN CHICAGO HOMES BEFORE AND AFTER MECHANICAL VENTILATION RETROFITS
Creator: Wang, Mingyu
Date: 2021
Description: PM2.5 are fine inhalable particles that are 2.5 micrometers or smaller in size. Indoor PM2.5 consists of outdoor PM2.5 (ambient PM2.5) that is...
Show morePM2.5 are fine inhalable particles that are 2.5 micrometers or smaller in size. Indoor PM2.5 consists of outdoor PM2.5 (ambient PM2.5) that is infiltrated into the indoor environment and indoor generated PM2.5 (non-ambient PM2.5). As people spend nearly 90% of their lifetimes indoors, with most of that time in their homes, PM2.5 exposure in homes results in severe health effects such as asthma. One strategy increasingly being used to dilute air pollutants generated indoors and improve indoor air quality (IAQ) in homes is the introduction of mechanical ventilation systems. However, mechanical ventilation systems also have the potential to introduce more ambient PM2.5 than relying on infiltration alone, although limited data exist to demonstrate the magnitude of impacts in occupied homes. The objective of this paper is to estimate the infiltration factor (Finf) of PM2.5 before and after installing mechanical ventilation systems in a subset of occupied homes. The data source utilized comes from the Breathe Easy Project, a more than 2-year-long study conducted in 40 existing homes in Chicago, IL aiming to explore the effects of three different types of mechanical ventilation system retrofits on IAQ and asthma. An automated algorithm was developed to remove indoor PM2.5 peaks in time-series data collected from optical particle counters deployed inside and outside of each home. The Finf was estimated using the resulting indoor/outdoor ratio with indoor peaks removed. Before mechanical ventilation retrofits, the weekly median Finf was 0.29 (summer median = 0.41, fall median = 0.26, winter median = 0.29, spring median = 0.30); after mechanical ventilation retrofits, the median Finf was 0.34 (winter median= 0.28, spring median = 0.45, summer median = 0.54, fall median = 0.20). Differences in Finf between pre- and post-intervention periods were not statistically significant (p = 0.23 from Wilcoxon signed rank tests). The median PM2.5 infiltration factor increased ~22% (from 0.27 to 0.33) with the installation of balanced ventilation systems with energy recovery ventilators (ERV), although differences were not statistically significant (Wilcoxon signed rank p = 0.35). The median PM2.5 infiltration factor decreased ~4% (from 0.28 to 0.27) after installing intermittent CFIS systems, which intermittently supply ventilation air through the existing central air handling units and associated filters (which were upgraded to a minimum of MERV 10 in all CFIS homes), although differences were not statistically significant (Wilcoxon signed rank p = 0.24). The median PM2.5 infiltration factor increased ~26% (from 0.35 to 0.44) with the installation of continuous exhaust-only systems, and differences were significant (Wilcoxon signed rank p = 0.04). These results suggest that the filtration mechanisms used on the CFIS and balanced systems were adequate for maintaining similar distributions of Finf values pre- and post-interventions whereas the increased delivery of outdoor air via the building envelope by exhaust-only systems significantly increased Finf following retrofits.
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Title: Architecture as a Communicator of Values and Identity Spaces for Public Safety and Community Benefits
Creator: Waidele Arteaga, Nicolas
Date: 2022
Description: Urban segregation, violence, and crimes are linked to drug trafficking. El Castillo Social Factory is an urban strategy that aims to recover...
Show moreUrban segregation, violence, and crimes are linked to drug trafficking. El Castillo Social Factory is an urban strategy that aims to recover the El Castillo neighborhood and prevent drug trafficking from advancing, understanding that police action is necessary but insufficient.This neighborhood is located on the southern periphery of Santiago in a commune called La Pintana and aspires to make its neighborhoods “more livable, healthy, and economically viable.” This proposal explores how investing in civic commons can make these goals a reality. First, it is essential to increase the presence of the State, strengthening existing services and adding new ones, with a focus on the care of children and young people. The second is to recover vacant lots and public spaces in poor condition or deteriorated through an “urban acupuncture” strategy based on the construction of many small or medium-sized projects. Art and sports are fundamental, allowing us to protect children and young people and offer them horizons of recreation and hope. The public buildings, institutions, land, water bodies, and infrastructure inherited from earlier generations are ready for us to see anew—as a robust network of civic assets ready to be activated for the current needs, desires, and dreams of all the people who share and shape them. El Castillo Social Factory offers a fresh look at our community anchors and the vibrant hubs our public spaces can become when we invest in collective urban life. Its vision focuses on positive transformation at the architectural scale—where personal experience and aspirations meet broad, long-range planning efforts—to spark the imagination and spur us to work together toward realizing the abundant potential of what we hold in common.
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Title: Automated Successive Baseline Schedule Model
Creator: Patel, Mihir Prakashbhai
Date: 2021
Description: The construction project involves many stakeholders and diverse phases. Usually, a construction schedule is initially set up as a simple ideal...
Show moreThe construction project involves many stakeholders and diverse phases. Usually, a construction schedule is initially set up as a simple ideal case scenario, but then, during construction, the project faces modifications such as delay, acceleration, and change in logic caused by the project’s complexity and inherent risk. To recover the damage(s) caused by these modifications, the parties responsible for them should be identified accurately. Researchers and practitioners developed and used various delay analysis models to quantify delays, but the selection of the model depends on the time of analysis, available information, and expertise of the analyst. So, the results can be biased. The general problem is that most delay analysis models consider only delays in quantifying impacts rather than every type of modification that impacted the project, including CPM logic changes and adding/removing activities during construction. This study proposes a new successive baseline model to enable the precise analysis of the impacts of all sorts of modifications that occur during construction. This model can achieve unbiased and accurate results. The analysis process can also be computerized into a web application to improve efficiency and productivity. The fundamental concepts of the various modifications that can occur in the work schedule during construction and the analysis of the modifications’ impacts are presented in this study. Issues related to concurrency, float ownership, type of modification, selection of delay analysis model, and challenges with automation are also highlighted to broaden the understanding disagreements of the parties to a construction contract. A case example is presented to prove the accuracy and usefulness of the proposed model and web application.
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