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Title: WISDOM FROM A MENTOR IN A MATTER OF MINUTES : INVESTIGATING A PROPOSED MODEL OF FLASH MENTORSHIP IN STUDENT-ALUMNI INTERACTIONS
Creator: Wisner, Amy Marie
Date: 2022
Collection: Electronic Theses & Dissertations
Description: Mentoring is an age-old practice that proves meaningful for protégés across contexts and program designs. Because both mentoring practice and mentoring research take place in a wide variety of domains and with seemingly limitless program details, it has become difficult to define or execute with any precision. Mentoring practitioners and researchers would benefit greatly from a mentorship model to inform their program designs and selection of mentoring type best-suited to the situation. In...
Show moreMentoring is an age-old practice that proves meaningful for protégés across contexts and program designs. Because both mentoring practice and mentoring research take place in a wide variety of domains and with seemingly limitless program details, it has become difficult to define or execute with any precision. Mentoring practitioners and researchers would benefit greatly from a mentorship model to inform their program designs and selection of mentoring type best-suited to the situation. In recent years, a type of mentoring that has gained popularity is flash mentorship. This short-term, one-time interaction is desirable because of the limited commitment required for everyone involved. However, little is known about the effectiveness of this type of mentorship. The current work sought to develop a model of effective flash mentorship with the broader goal of establishing best practices for pairing mentors with protégés in meaningful ways. A proposed model of flash mentorship posited that relationship quality and advice quality predicted protégé situational satisfaction. Antecedents of relationship quality were posited to include attraction and deep-level similarity. Antecedents of advice quality were posited to include message features and mentor expertise. Although all causal links posited by the model were of sufficient magnitude to be consistent with predictions, the fit of the model proved insufficient. Limitations of the findings and recommendations for future research are discussed.
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Title: COLLECTIVE ACTION AND SEED PRODUCTION : A PATHWAY FOR WOMEN'S EMPOWERMENT AND COMMUNITY SEED SECURITY IN INDIA
Creator: Lewis, Arena
Date: 2022
Collection: Electronic Theses & Dissertations
Description: There exists a wide range of development interventions that aim to 1) empower women and 2) ensure food security for rural smallholder farmers. These types of interventions, implemented separately, have had varied success. The implementation of interventions to achieve both women’s empowerment and seed security simultaneously has been researched in a few studies, but the successful achievement of these goals has rarely been observed. This study investigates the impact a layered seed production...
Show moreThere exists a wide range of development interventions that aim to 1) empower women and 2) ensure food security for rural smallholder farmers. These types of interventions, implemented separately, have had varied success. The implementation of interventions to achieve both women’s empowerment and seed security simultaneously has been researched in a few studies, but the successful achievement of these goals has rarely been observed. This study investigates the impact a layered seed production/self-help group program had on women’s empowerment and seed security. The research was conducted in 2 districts in Uttar Pradesh, India using semi-structured interviews of 36 participants. The findings indicate that, through the collective power of self-help groups, women were empowered and seed security was increased for women within the group as well as the greater community through the seed production program. Further, women who participated in the seed production program in addition to their regular self-help group membership, were empowered through additional channels specific to the layered seed production systems. This research indicates that self-help groups can act as a platform for development interventions and integrate well with seed system interventions.
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Title: DESIGN AND ENGINEERING OF STARCH-BASED POLYMER MATERIALS AS SUBSTITUTES FOR PERSISTENT NON-BIODEGRADABLE PLASTICS
Creator: Kulkarni, Apoorva Chandrakant
Date: 2022
Collection: Electronic Theses & Dissertations
Description: Replacing carbon-carbon backbone persistent hydrocarbon plastics with biobased and biodegradable plastics offers value proposition of reduced carbon footprint and an environmentally responsible end-of-life. This work focuses on design and engineering of starch based polymeric materials as substitutes for non-biodegradable plastics. The biodegradability of these bioplastics in aqueous environment was evaluated.Starch foams are being used as replacement for petroleum-based foams in insulation...
Show moreReplacing carbon-carbon backbone persistent hydrocarbon plastics with biobased and biodegradable plastics offers value proposition of reduced carbon footprint and an environmentally responsible end-of-life. This work focuses on design and engineering of starch based polymeric materials as substitutes for non-biodegradable plastics. The biodegradability of these bioplastics in aqueous environment was evaluated.Starch foams are being used as replacement for petroleum-based foams in insulation and cushion protection applications. However, moisture sensitivity remains a problem resulting in collapse of cell structure and loss of mechanical integrity. First section of the thesis focuses on engineering high-performance starch foams with enhanced moisture resistance using reactive extrusion processing technology. Chitosan, polyvinyl butyral (PVB) and sodium trimetaphosphate (STMP) were used with water as a plasticizer and a blowing agent to make foams with desired physico-mechanical properties. The resulting foams were hydrophobic, insoluble in water, and showed improved moisture resistance. The biodegradability of the foams was not impacted – they were completely biodegradable as established by ASTM/ISO standards. Crosslinking of starch with STMP increased the compressive strength of the foams by three times compared to control foams. Optimization of process parameters ensured an efficient, cost-effective route towards commercialization. In the second section, our group’s chemically modified thermoplastic starch (MTPS) prepared by reactive extrusion technology was explored in three different applications. First, MTPS, was melt blended with glycol modified polyethylene terephthalate (PETG) using transesterification chemistry to synthesize MTPS-g-PETG in situ graft copolymer with 33% grafting. Mechanical and thermal properties of the blend were evaluated and compared with neat PETG. The addition of starch into PETG molecular backbone did not result in PETG biodegradability. This finding refutes many claims of biodegradability of non-biodegradable polymers by the addition of starch and similar additives. in the marketplace. Second, the use of MTPS as a biobased and biodegradable nucleating agent and barrier property enhancer in polylactide (PLA) was explored. Our findings establish that MTPS accelerates the rate of crystallization of PLA (polylactide polymers) by up to 98 times at 100°C, reducing the half time for crystallization from 20 mins to less than 1 minute. Oxygen barrier properties of PLA was improved 127% without causing detrimental impact on mechanical properties or biodegradability. Third application focuses on using MTPS as a carrier for iodine, which is a very effective and strong antimicrobial agent. The antimicrobial starch-iodine complex in pellet form was manufactured by extrusion processing. The new MTPS-iodine complex was incorporated in various proportions to commercial fully biodegradable-compostable polyester films. The morphological, mechanical, and antibacterial properties of these films were evaluated and compared with current commercial additives used to obtain antibacterial properties. The last section focuses on the end-of-life evaluations for biobased and biodegradable plastics using kinetics approach. The effect of temperature on biodegradation of cellulose and Poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV) in an aqueous environment seeded with a biologically aggressive microbial inoculum was studied. A global equation was derived from the reparametrized Arrhenius equation and the kinetic rate law to estimate the time required for 90% removal of polymer from the low temperature ocean environment. The t90 (time required to remove 90% of the polymer carbon from the environment) for PHBV at 10°C ranged from 6.2-6.9 years. The t90 of cellulose at 10 C was found to be 1.1-1.2 years. ASTM/ISO standards for measuring and reporting ocean biodegradability is static and conducted at one temperature (30°C), whereas ocean temperatures can vary from −1.8 °C to 33.4 °C. The kinetic analysis and model developed can provide a method to estimate time for complete removal of the biodegradable polymer carbon in ocean environments.
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Title: STREET SKATEBOARDING MITIGATION THROUGH STRATEGIC LANDSCAPE PLANTINGS
Creator: Lentz, Elijah Graham
Date: 2022
Collection: Electronic Theses & Dissertations
Description: Bent handrails, wax covered ledges, and chipped concrete are just a few of the common damages that are far too often the consequence of street skateboarding. Too many public properties have been damaged, trespassed, and plagued by street skateboarders as they use urban architecture and amenities to perform skate tricks on. These areas are not designed for skateboarding and often suffer the consequences as street skateboarders use urban spaces for sport. The purpose of this research is to shed...
Show moreBent handrails, wax covered ledges, and chipped concrete are just a few of the common damages that are far too often the consequence of street skateboarding. Too many public properties have been damaged, trespassed, and plagued by street skateboarders as they use urban architecture and amenities to perform skate tricks on. These areas are not designed for skateboarding and often suffer the consequences as street skateboarders use urban spaces for sport. The purpose of this research is to shed light on the ongoing conflict that occurs between street skateboarders and urban public spaces and to propose design solutions utilizing strategic landscape plantings aimed to deter street skateboarding. By using a Likert-type survey with perspective design renderings used to collect and compare data from both skateboarders and non-skateboarders, as well as observing and recording evidence of street skateboarding and its damages, solutions best fit for the study’s site area of The Eli and Edythe Broad Art Museum will be determined. Ultimately, this study’s conclusions are intended to add to the knowledge of combating street skateboarding conflict. This study’s findings show that only in specific instances there are significant differences of perceptions between skateboarders and non skateboarders when determining the effectiveness of planting based street skateboarding deterrents and that a street skateboarding conflict exists at the Eli and Edythe Broad Art Museum. Having just made its debut at the Tokyo 2020 Summer Olympic Games, it is inevitable new effective street skateboarding mitigation strategies will be needed as the sport continues to grow around the world.
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Title: Fast and Memory-Efficient Subspace Embeddings for Tensor Data with Applications
Creator: Zare, Ali
Date: 2022
Collection: Electronic Theses & Dissertations
Description: The widespread use of multisensor technology and the emergence of big data sets have brought the necessity to develop more versatile tools to represent higher-order data with multiple aspects and high dimensionality. Data in the form of multidimensional arrays, also referred to as tensors, arise in a variety of applications including chemometrics, physics, hyperspectral imaging, high-resolution videos, neuroimaging, biometrics, and social network analysis. Early multiway data analysis...
Show moreThe widespread use of multisensor technology and the emergence of big data sets have brought the necessity to develop more versatile tools to represent higher-order data with multiple aspects and high dimensionality. Data in the form of multidimensional arrays, also referred to as tensors, arise in a variety of applications including chemometrics, physics, hyperspectral imaging, high-resolution videos, neuroimaging, biometrics, and social network analysis. Early multiway data analysis approaches used to reformat such tensor data as large vectors or matrices and would then resort to dimensionality reduction methods developed for low-dimensional data. However, by vectorizing tensors, the inherent multiway structure of the data and the possible correlation between different dimensions will be lost, in some cases resulting in a degradation in the performance of vector-based methods. Moreover, in many cases, vectorizing tensors leads to vectors with extremely high dimensionality that might render most existing methods computationally impractical. In the case of dimension reduction, the enormous amount of memory needed to store the embedding matrix becomes the main obstacle. This highlights the need for approaches that are applied to tensor data in their multi-dimensional form. To reduce the dimension of an $n_1 \times n_2 \times \dots \times n_d$ tensor to $m_1 \times m_2 \times \dots \times m_d$ with $m_j \leq n_j$, MPCA\footnote{Multilinear Principal Component Analysis} would change the memory requirement from $\prod_{j=1}^d m_jn_j$ for vector PCA to $\sum_{j=1}^d m_jn_j$, which can be a considerable improvement.On the other hand, tensor dimension reduction methods such as MPCA need training samples for the projection matrices to be learned. This makes such methods time consuming and computationally less efficient than oblivious approaches such as the Johnson-Lindenstrauss embedding. The term \textit{oblivious} refers to the fact that one does not need any data samples beforehand to learn the embedding that projects a new data sample onto a lower-dimensional space.\\ In this thesis, first a review of tensor concepts and algebra as well as common tensor decompositions is presented. Next, a modewise JL approach is proposed for compressing tensors without reshaping them into potentially very large vectors. Theoretical guarantees for the norm and inner product approximation errors as well as theoretical bounds on the embedding dimension are presented for data with low CP rank, and the corresponding effects of basis coherence assumptions are addressed. Experiments are performed using various choices of embedding matrices. Results verify the validity of one- and two-stage modewise JL embeddings in preserving the norm of MRI and synthesized data constructed from both coherent and incoherent bases. Two novel applications of the proposed modewise JL method are discussed. (i) Approximate solutions to least squares problems as a computationally efficient way of fitting tensor decompositions: The proposed approach is incorporated as a stage in the fitting procedure, and is tested on relatively low-rank MRI data. Results show improvement in computational complexity at a slight cost in the accuracy of the solution in the Euclidean norm. (ii) Many-Body Perturbation Theory problems involving energy calculations: In large model spaces, the dimension sizes of tensors can grow fast, rendering the direct calculation of perturbative correction terms challenging. The second-order energy correction term as well as the one-body radius correction are formulated and modeled as inner products in such a way that modewise JL can be used to reduce the computational complexity of the calculations. Experiments are performed on data from various nuclei in different model space sizes, and show that in the case of large model spaces, very good compression can be achieved at the price of small errors in the estimated energy values.
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Title: Improving the Efficiency of Residential Buildings in Rural Alaska : An Analysis of Existing Infrastructure and Its Importance in Creating Energy-Efficient Homes
Creator: Milan, Maria
Date: 2022
Collection: Electronic Theses & Dissertations
Description: Rural communities in Alaska, many of which have a high Alaska Native population, currently face significant housing challenges. In a climate that can become extremely cold, houses are generally lacking in energy efficiency. Residents pay high rates for both oil and electricity to heat and operate their homes. Their homes are much smaller and with higher occupancy in comparison to typical U.S. homes. In addition, as the winter season brings sub-zero temperatures, windows remain shut with...
Show moreRural communities in Alaska, many of which have a high Alaska Native population, currently face significant housing challenges. In a climate that can become extremely cold, houses are generally lacking in energy efficiency. Residents pay high rates for both oil and electricity to heat and operate their homes. Their homes are much smaller and with higher occupancy in comparison to typical U.S. homes. In addition, as the winter season brings sub-zero temperatures, windows remain shut with limited mechanical or natural ventilation, also creating indoor air quality concerns. To date there has been limited studies of rural Alaskan communities’ housing, to better understand and quantify such housing challenges. This research focuses on a detailed study of the rural Alaskan community of Unalakleet. Located on the western shore of Alaska, this coastal community of approximately 765 people faces many housing challenges, similar to other rural Alaskan communities. Through collaboration with the housing authority in Unalakleet, this research conducted home energy assessments and resident interviews in the summer of 2021, including 27 energy assessments and 22 interviews. The purpose of the energy assessments was to collect information on typical building features and data, as well as to identify housing challenges. The interviews were generally completed for homes that also had an energy assessment and were used to better understand residents’ perspectives on energy and housing challenges beyond what was observed in the assessments. Blower door tests suggest that homes are usually small and tight, with leakiness around areas like the windows, where mold frequently was observed. Short-term indoor air quality monitoring suggests that some homes, especially those less than 46 m2 , had high CO2 concentrations, relative to others. Some homes had significant mold growth, and others had many areas of damage. Still, interviews with community members suggest that they were grateful for their housing and the ability to live in Unalakleet. The overall purpose of this research is to provide evidence to quantify the typical housing characteristics presence in rural Alaskan communities, as well as to provide results that motivate and support opportunities for new, more efficient housing. The introduction discusses major housing challenges, from high energy bills to the history of inefficient infrastructure in rural Alaska. Physical characteristics of assessed homes, followed by indoor air quality and air flow, are discussed in Chapters 2 and 3, respectively. Finally, Chapter 4 uses data collected from the 27 housing assessments to create a building energy model, where energy usage in existing housing is modeled to represent a ‘typical’ rural Alaskan home. The results of this model show where the largest improvements in efficiency can be made, especially in adding higher R-value insulation. The conclusion provides a brief overview of research contribution, limitations, and future work.
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Title: Optimizing and Improving the Fidelity of Reactive, Polarizable Molecular Dynamics Simulations on Modern High Performance Computing Architectures
Creator: O'Hearn, Kurt A.
Date: 2022
Collection: Electronic Theses & Dissertations
Description: Reactive, polarizable molecular dynamics simulations are a crucial tool for the high-fidelity study of large systems with chemical reactions. In support of this, several approaches have been employed with varying degrees of computational cost and physical accuracy. One of the more successful approaches in recent years, the reactive force field (ReaxFF) model, wasdesigned to fill the gap between traditional classical models and quantum mechanical models by incorporating a dynamic bond order...
Show moreReactive, polarizable molecular dynamics simulations are a crucial tool for the high-fidelity study of large systems with chemical reactions. In support of this, several approaches have been employed with varying degrees of computational cost and physical accuracy. One of the more successful approaches in recent years, the reactive force field (ReaxFF) model, wasdesigned to fill the gap between traditional classical models and quantum mechanical models by incorporating a dynamic bond order potential term. When coupling ReaxFF with dynamic global charges models for electrostatics, special considerations are necessary for obtaining highly performant implementations, especially on modern high-performance computing architectures.In this work, we detail the performance optimization of the PuReMD (PuReMD Reactive Molecular Dynamics) software package, an open-source, GPLv3-licensed implementation of ReaxFF coupled with dynamic charge models. We begin byexploring the tuning of the iterative Krylov linear solvers underpinning the global charge models in a shared-memory parallel context using OpenMP, with the explicit goal of minimizing the mean combined preconditioner and solver time. We found that with appropriate solver tuning, significant speedups and scalability improvements were observed. Following these successes, we extend these approaches to the solvers in the distributed-memory MPI implementation of PuReMD, as well as broaden the scope of optimization to other portions of the ReaxFF potential such as the bond order computations. Here again we find that sizable performance gains were achieved for large simulations numbering in the hundreds of thousands of atoms.With these performance improvements in hand, we next change focus to another important use of PuReMD -- the development of ReaxFF force fields for new materials. The high fidelity inherent in ReaxFF simulations for different chemistries oftentimes comes at the expense of a steep learning curve for parameter optimization, due in part to complexities in the high dimensional parameter space and due in part to the necessity of deep domain knowledge of how to adequately control the ReaxFF functional forms. To diagnose and combat these issues, a study was undertaken to optimize parameters for Li-O systems using the OGOLEM genetic algorithms framework coupled with a modified shared-memory version of PuReMD. We found that with careful training set design, sufficient optimization control with tuned genetic algorithms, and improved polarizability through enhanced charge model use, higher accuracy was achieved in simulations involving ductile fracture behavior, a difficult phenomena to hereto model correctly.Finally, we return to performance optimization for the GPU-accelerated distributed-memory PuReMD codebase. Modern supercomputers have recently achieved exascale levels of peak arithmetic rates due in large part to the design decision to incorporate massive numbers of GPUs. In order to take advantage of such computing systems, the MPI+CUDA version of PuReMD was re-designed and benchmarked on modern NVIDIA Tesla GPUs. Performance on-par with or exceeding the LAMMPS Kokkos, a ReaxFF implementation developed at Scandia National Laboratories, with PuReMD typically out-performing LAMMPS Kokkos at larger scales.
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Title: EXPLORING THE RELATIONSHIP BETWEEN RESILIENCE AND ADVERSE IMPACT OF STUTTERING
Creator: Grobbel, Hannah
Date: 2022
Collection: Electronic Theses & Dissertations
Description: Children who stutter often experience adverse impact such as bullying, negative thought patterns, and reduced self-esteem that result from living with their condition. Research suggests that there are factors that may place a child who stutters at greater risk for adverse impact as well as protective factors that mitigate this risk. The aim of this study is to examine the relationship between resilience and stuttering’s adverse impact in children. Resilience reflects both internal factors...
Show moreChildren who stutter often experience adverse impact such as bullying, negative thought patterns, and reduced self-esteem that result from living with their condition. Research suggests that there are factors that may place a child who stutters at greater risk for adverse impact as well as protective factors that mitigate this risk. The aim of this study is to examine the relationship between resilience and stuttering’s adverse impact in children. Resilience reflects both internal factors such as grit and the ability to cope and external factors such as family support and access to resources. We collected data from children who stutter and their parents to assess children’s resilience and stuttering’s adverse impact using standardized assessments. We then explored the relationship between resilience and adverse impact through descriptive statistics, linear regression, and correlation analyses. Results revealed that even children in the youngest, preschool-aged group showed adverse impact due to stuttering. We also found that greater resilience predicted less adverse impact in in school-aged and adolescent children who stutter. These findings provide insight into the experience of stuttering and offer support for treatments that incorporate resilience building into therapy to help mitigate adverse impact experienced by children who stutter.
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Title: The Impact of Social Class on Students’ Pre-College Perceptions of Co-Curricular Involvement
Creator: Rossman, Danielle
Date: 2022
Collection: Electronic Theses & Dissertations
Description: This dissertation uses a cross sectional quantitative design to investigate the relationship between first-year college students’ social class and their pre-college interest in engaging in co-curricular experiences during college, their motivations for engaging in co-curricular experiences, and their perceptions of whether co-curricular activities will teach them leadership and work ethic skills. The study also investigated multiple variables to address social class- including metrics of...
Show moreThis dissertation uses a cross sectional quantitative design to investigate the relationship between first-year college students’ social class and their pre-college interest in engaging in co-curricular experiences during college, their motivations for engaging in co-curricular experiences, and their perceptions of whether co-curricular activities will teach them leadership and work ethic skills. The study also investigated multiple variables to address social class- including metrics of subjective social status and socioeconomic status. The study used data from two surveys that were administered to a sample (N = 839) of first-year, first-time college students from a regional comprehensive university prior to their matriculation. The findings of this study indicate that students’ awareness of their socioeconomic status was the only significant predictor of their interest in getting involved in co-curricular activities during college. Students’ perceived family contribution to their college education significantly predicted their interest in working during college, while social class had no impact on a student’s interest in joining fraternity and sorority life or in student government association. There was a significant relationship between a student’s race, gender, and high school extracurricular experiences and their motivation for engagement. A student’s Expected Family Contribution was not a significant predictor of the student’s interest, motivation, or perception related to involvement. Students’ awareness of their socioeconomic status also impacted their perceptions that they could learn leadership skills and work ethic from co-curricular activities, while students with higher subjective social class were more likely to believe they could learn leadership skills from being a participant or member in co-curricular experiences. Implications of these findings for research, theory and practice are offered. More research is needed that explores the impact of social class, and incorporates multiple diverse metrics of social class, on students’ college experience. Studies that investigate the ability of on-campus employment to serve as a high impact proactive for students who may not otherwise have the ability to participate in co-curricular experiences on campus are also needed.
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Title: VISIONING THE AGRICULTURE BLOCKCHAIN : THE ROLE AND RISE OF BLOCKCHAIN IN THE COMMERCIAL POULTRY INDUSTRY
Creator: Fennell, Chris
Date: 2022
Collection: Electronic Theses & Dissertations
Description: Blockchain is an emerging technology that is being explored by technologists and industry leaders as a way to revolutionize the agriculture supply chain. The problem is that human and ecological insights are needed to understand the complexities of how blockchain could fulfill these visions. In this work, I assert how the blockchain's promising vision of traceability, immutability and distributed properties presents advancements and challenges to rural farming. This work wrestles with the...
Show moreBlockchain is an emerging technology that is being explored by technologists and industry leaders as a way to revolutionize the agriculture supply chain. The problem is that human and ecological insights are needed to understand the complexities of how blockchain could fulfill these visions. In this work, I assert how the blockchain's promising vision of traceability, immutability and distributed properties presents advancements and challenges to rural farming. This work wrestles with the more subtle ways the blockchain technology would be integrated into the existing infrastructure. Through interviews and participatory design workshops, I talked with an expansive set of stakeholders including Amish farmers, contract growers, senior leadership and field supervisors. This research illuminates that commercial poultry farming is such a complex and diffuse system that any overhaul of its core infrastructure will be difficult to ``roll back'' once blockchain is ``rolled out.'' Through an HCI and sociotechnical system perspective, drawing particular insights from Science and Technology Studies theories of infrastructure and breakdown, this dissertation asserts three main concerns. First, this dissertation uncovers the dominant narratives on the farm around revision and ``roll back'' of blockchain, connecting to theories of version control from computer science. Second, this work uncovers that a core concern of the poultry supply chain is death and I reveal the sociotechnical and material implications for the integration of blockchain. Finally, this dissertation discusses the meaning of ``security’’ for the poultry supply chain in which biosecurity is prioritized over cybersecurity and how blockchain impacts these concerns. Together these findings point to significant implications for designers of blockchain infrastructure and how rural workers will integrate the technology into the supply chain.
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Title: EXPLORING STUDENTS’ UNDERSTANDING OF INTERACTIONS AND ENERGY ACROSS CHEMISTRY AND BIOLOGY
Creator: Noyes, Keenan Chun Hong Lee
Date: 2022
Collection: Electronic Theses & Dissertations
Description: One of the goals of science education is to help students make sense of the world around them. To that end, it is critical that students understand the central ideas in each discipline like, in chemistry, energy and interactions. These ideas are of particular importance because they are directly related to one another and are relevant across other science disciplines. Unfortunately, researchers have found that students often struggle to develop a deep understanding of these ideas. To uncover...
Show moreOne of the goals of science education is to help students make sense of the world around them. To that end, it is critical that students understand the central ideas in each discipline like, in chemistry, energy and interactions. These ideas are of particular importance because they are directly related to one another and are relevant across other science disciplines. Unfortunately, researchers have found that students often struggle to develop a deep understanding of these ideas. To uncover better ways to support students’ learning, I explored how students understand interactions and energy in both chemistry and biology.In this dissertation, I focused on London dispersion forces (LDFs), a type of intermolecular force (IMF) which occurs between all atoms and molecules. Specifically, I used the lens of causal mechanistic reasoning to think about students’ knowledge. That is, how students connect the properties and behaviors of the underlying entities to the overall phenomenon. If we can help students to develop this type of understanding, they may be able to make powerful predictions about new, unfamiliar phenomena in which IMFs play an important role. Additionally, I explored how students thought about the energy changes which result from the formation of LDFs. Lastly, I designed assessments to elicit and characterize explanations of protein-ligand binding, a biological phenomenon governed by IMFs. To explore these questions, I used a mix of qualitative and quantitative techniques. I designed tasks to elicit causal mechanistic responses from students, using students’ responses to refine the task design. I also developed coding schemes to characterize students’ engagement in causal mechanistic reasoning. Furthermore, I developed and used automated resources to analyze thousands of responses in a matter of minutes. In these studies, I focused primarily on undergraduate students enrolled in Chemistry, Life, the Universe, and Everything (CLUE), a transformed, core-idea centered general chemistry curriculum. From these studies, I found that the majority of CLUE students could leverage electrostatic ideas to explain LDFs, and that a meaningful proportion of those students could provide a full causal mechanistic account. This highlights the importance of emphasizing these interactions, and the mechanism by which they form, throughout the general chemistry course sequence. Additionally, students who used causal mechanistic reasoning to discuss LDFs were more likely to use that same reasoning in the context of the associated changes in potential energy. However, this relationship was weaker among those providing a partially causal mechanistic response. This suggests that more work needs to be done to find ways of supporting students to connect the ideas of interactions and energy. Additionally, in this thesis, I describe the process by which I used iterative design to develop a task eliciting causal mechanistic explanations of a biological phenomenon. In future work, these materials can be used to explore how broader groups of students engage with this task in an effort to foster interdisciplinary coherence.
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Title: FATE OF SILVER NANOPARTICLES DURING SIMULATED COMMERCIAL PROCESSING OF FRESH-CUT LETTUCE
Creator: Gunathilaka, Gayathri Upeksha
Date: 2022
Collection: Electronic Theses & Dissertations
Description: ABSTRACTFATE OF SILVER NANOPARTICLES DURING SIMULATED COMMERCIAL PROCESSING OF FRESH-CUT LETTUCEByGayathri Upeksha GunathilakaThe use of silver nanoparticles (Ag NPs) in pesticides could lead to residual levels in food crops, thus raising both food safety and environmental concerns. The effectiveness of typical produce processing practices to remove Ag NPs from fresh produce is poorly understood. Further, little is known about the behavior of Ag NPs in wash water during commercial production...
Show moreABSTRACTFATE OF SILVER NANOPARTICLES DURING SIMULATED COMMERCIAL PROCESSING OF FRESH-CUT LETTUCEByGayathri Upeksha GunathilakaThe use of silver nanoparticles (Ag NPs) in pesticides could lead to residual levels in food crops, thus raising both food safety and environmental concerns. The effectiveness of typical produce processing practices to remove Ag NPs from fresh produce is poorly understood. Further, little is known about the behavior of Ag NPs in wash water during commercial production of fresh-cut produce, which limits our ability to design effective mitigation strategies.The first study evaluated the behavior of Ag NPs over time when exposed to commercially applicable chlorine concentrations (2–100 mg chlorine/L) in simulated lettuce wash water. Aggregation and dissolution of Ag NPs (5 mg/L) were evaluated in the presence and absence of dissolved lettuce extract (DLE, 0.1%). Aggregate size of Ag NPs increased faster in the presence of chlorine (49 to 431 nm) compared to the control (P < 0.05). Lower dissolved Ag concentrations and more negative zeta potentials were found in the presence of chlorine (0.01 to 0.03 mg/L and -39 to -95 mV) and DLE (0.01 to 0.14 mg/L and -28 to -32 mV), as compared to the control (0.54 to 0.8 mg/L and -10 to -20 mV) (P < 0.05). Transmission electron microscopy with energy dispersive spectroscopy confirmed the formation of composite AgCl-Ag NPs particles in the presence of chlorine. The increased aggregate size over time likely resulted from nucleation and crystal growth of AgCl. In the presence of DLE, Ag NPs and AgCl precipitates were embedded in and bound to the DLE matrix. These observations suggest that chlorine and plant-released organic matter could substantially change the fate of Ag NPs in wash water and subsequently their environmental impact. In the second study the removal of Ag NPs from Ag NP-contaminated lettuce leaves was investigated during batch and small-scale pilot processing. First, a batch-type system (4-L carboy jar) was used to evaluate the impact of commercial produce sanitizers and simulated leafy green processing water on the removal of Ag NPs from contaminated lettuce. Peroxyacetic acid (PAA; 80 mg/L) and chlorine (100 mg/L and pH 6.5) were used with/without 2.5% (w/v) organic load as washing treatments with deionized water serving as the control treatment. Treating lettuce with the organic load alone, organic load with chlorine, chlorine alone, 0% organic load and peroxyacetic acid removed about 2.7%–6.6% of Ag from the lettuce after 5 min of washing. Thereafter, the removal of Ag NPs from contaminated lettuce was assessed using a small-scale pilot processing line during 90 seconds of flume-washing followed by centrifugal drying (a typical washing practice in commercial produce processing). The Ag removal efficiency ranged between 0.3% to 3%, probably resulting from strong binding of Ag with plant organic materials. Significantly greater Ag concentrations were found in the centrifugal water than in flume water, suggesting that centrifugation removed additional Ag from lettuce. The low Ag removal observed in both the simulated batch-type and pilot-scale produce washing systems demonstrate that typical produce processing conditions may not be effective in removing Ag NPs from contaminated produce. Thus, it is necessary to further investigate and develop effective methods for the Ag NP removal from contaminated produce.
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Title: PRODUCTIVITY IMPACTS OF STRATEGIES TO ENHANCE RUMINANT FIBER DIGESTION
Creator: Ibraheem, Muhammad
Date: 2022
Collection: Electronic Theses & Dissertations
Description: Strategies to improve forage fiber digestibility can increase dairy sustainability. Reducing lignin content through natural breeding or genetic engineering can improve DMI, neutral detergent fiber (NDF) digestibility and feed efficiency. A 60 mid-lactating cow experiment was carried out to compare production and nutrient digestibility responses to low-lignin vs. conventional alfalfa hay. The 3 treatments provided 0% (conventional), 50% (blend) and 100% low-lignin alfalfa; all diets contained...
Show moreStrategies to improve forage fiber digestibility can increase dairy sustainability. Reducing lignin content through natural breeding or genetic engineering can improve DMI, neutral detergent fiber (NDF) digestibility and feed efficiency. A 60 mid-lactating cow experiment was carried out to compare production and nutrient digestibility responses to low-lignin vs. conventional alfalfa hay. The 3 treatments provided 0% (conventional), 50% (blend) and 100% low-lignin alfalfa; all diets contained 31.8% alfalfa on a dry matter (DM) basis. Low-lignin alfalfa decreased total-tract NDF digestibility and milk fat concentration in a dose-dependent manner. All other nutrient and production parameters were unaffected. Therefore, observed NDF digestibility and milk fat results suggest that the low-lignin alfalfa provided less physically effective fiber, failing to demonstrate obvious benefits. Another strategy for improving NDF digestibility involves use of different trace mineral supplements. In a small meta-analysis that included 8 studies and 12 comparisons in both sectors, beef and dairy, effects of hydroxy vs. sulfate trace minerals (TM) on nutrient digestibility and DM intake were investigated. Study design, sector and method of digestibility analysis were the factors included in the analysis. Hydroxy TM increased DM digestibility only in beef cattle and NDF digestibility, which was affected by digestibility analysis method. Total collection studies showed the greatest benefit, followed by use of undigested NDF as a digestibility marker, but 24-h in situ approaches did not show any significant response. In conclusion, adopting multiple strategies for optimizing fiber digestibility might help the dairy industry achieve greater feed efficiency goals.
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Title: A POTENTIAL ROLE FOR EARLY GUT MICROBIAL COLONIZATION IN INFANT BEHAVIOR AND CHILD SLEEP DISORDERS
Creator: Ma, Tengfei
Date: 2022
Collection: Electronic Theses & Dissertations
Description: There is increasing evidence from pre-clinical and human studies implicating the microbiota–gut–brain axis in behavior and sleep physiology. Infancy is a critical time period for brain development and is vulnerable to the harmful effects of gut dysbiosis. Thus, it is crucial to understand how gut microbial colonization during this period may influence behavior and sleep physiology in the later stages of life.We analyzed data from 194 mother-infant pairs from the Michigan Archive for Research...
Show moreThere is increasing evidence from pre-clinical and human studies implicating the microbiota–gut–brain axis in behavior and sleep physiology. Infancy is a critical time period for brain development and is vulnerable to the harmful effects of gut dysbiosis. Thus, it is crucial to understand how gut microbial colonization during this period may influence behavior and sleep physiology in the later stages of life.We analyzed data from 194 mother-infant pairs from the Michigan Archive for Research on Child Health (MARCH) cohort Study. Clinical and demographic information was obtained from the birth certificate and interview during pregnancy and childhood. Fecal samples from infants at 3-9 months of age were sequenced at the V4 region of the 16S rRNA gene. In the first study, which examined whether feeding practices may affect early gut microbial colonization, we found that the gut microbiota of infants who were exclusively breastfed displayed a significantly lower Shannon diversity (p-adjust < 0.001) and a different gut microbiota composition than infants who were not breastfed (p-value = 0.001). Among the exclusively breastfed infants, recipients of supplemental vitamin D displayed a significantly lower Shannon diversity (p-adjust = 0.007) and different gut microbiota composition structure than non-supplemented, breastfed infants (p-value = 0.02). In addition, several individual taxa were identified to be associated with different feeding practices. In the second study, we examined whether gut microbiota in early infancy was associated with temperament in the nine-month-old infants. We identified that a microbial cluster characterized by a higher abundance of Bifidobacterium, Veillonella, and Escherichia-Shigella that was associated with lower emotionality scores (coefficient = -0.58, p-value = 0.02) compared to a cluster characterized by a higher abundance of Bacteroides. This association was especially prominent among infants who were not supplemented with vitamin D (coefficient = -1.01, p-value = 0.01), while no significant association was found among infants who were supplemented (coefficient = -0.43, p-value = 0.20). In the final aim, we assessed the association between gut microbiota in early infancy and the difficulty of initiating and maintaining sleep at age of two years. The gut microbiota of children who had difficulty maintaining sleep displayed significantly higher Shannon index (OR: 2.41, 95% CI= 1.23-4.93, p-adjust < 0.04) and Chao 1 index (OR: 1.01, 95% CI= 1.0-1.03, p-adjust < 0.008) after adjustment for covariates. We also observed that gut microbiota composition was significantly different between children with difficulty initiating (p-value= 0.043) and maintaining sleep (p-value= 0.004) by PERMANOVA based on the unweighted UniFrac distance metric. In conclusion, these results from analysis in a prospective cohort study suggest that early gut microbial colonization is shaped by breastfeeding status, vitamin D supplement, and maternal characteristics including gestational age, delivery mode and education level. Our findings suggested that the infant gut microbiome clusters may be associated with the temperament characteristic of negative emotionality in 9-month-old infants. We also demonstrated a significant association between infant gut microbiome composition and sleep problems in 2-year-old children. Thus, our results add to the evidence that early gut microbial colonization may be linked with brain outcomes with potential long-term effects.
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Title: Quantitative Analysis of New Key Factors of Immune Cells in Autoimmune Diseases
Creator: Bunn, Demarcus
Date: 2022
Collection: Electronic Theses & Dissertations
Description: AbstractExplorations of New Key Factors of Immune Cells in Autoimmune Diseases By Demarcus Bunn The work presented in this dissertation demonstrates an emerging role of immune cells in type one diabetes (T1D) and multiple sclerosis (MS). The immune cells that will be presented are neutrophils and T-cells. Presented work shows an altered cell metabolism in both disease states that leads to further secondary complications. An overview of the immunology, as well as each autoimmune disease, will...
Show moreAbstractExplorations of New Key Factors of Immune Cells in Autoimmune Diseases By Demarcus Bunn The work presented in this dissertation demonstrates an emerging role of immune cells in type one diabetes (T1D) and multiple sclerosis (MS). The immune cells that will be presented are neutrophils and T-cells. Presented work shows an altered cell metabolism in both disease states that leads to further secondary complications. An overview of the immunology, as well as each autoimmune disease, will be presented. Experimental efforts to increase or decrease cell metabolism in order to alleviate secondary complications will be shown. Furthermore, the use of 3D printed devices for in vitro models mimicking these disease states properties will be presented.Individuals T1D have a history of being more susceptible to infection. This section of the dissertation will demonstrate how a once forgotten pancreatic peptide, C-peptide, has a positive effect on raising immunity through improving immune cell energetics. Previous studies in the Spence lab have shown that C-peptide only binds to red blood cells (RBC) in the presence of albumin, but for the biological changes, Zn2+ is needed. Spence lab research has shown that the combination of C-peptide/Zn2+/albumin increases the metabolism of RBCs. This work shows novel data showing that C-peptide binds specifically to other cell types. Additionally, changes in cell metabolism will be investigated. This portion of the dissertation is important for alleviating reoccurring and persistent infections.MS is characterized by the destruction of the myelin sheath around the nerves. The cell type that does the damage is T lymphocytes. However, little research has been done investigating what makes the permeability of the blood-brain barrier increase. Here, we will introduce the potential role of NETosis, a form of programmed cell death, has on blood brain barrier permeability. There have been recent reports that exogenous adenosine triphosphate (ATP) increases the rate of NETosis production in vitro. Previous work in the Spence lab has shown that RBCs from individuals with MS secrete significantly more ATP than control red blood cells. Presented work will show that ATP derived directly from RBCs causes dysregulation of NETosis. The concluding section of the dissertation will be dedicated to 3D printing. An overview of the current state and future advancements of 3D printing will be presented. Presented work will show the use of 3D printing to provide more relevant conditions for in vitro experiments. Here, 3D printed models were used to investigate immune cell behaviors and changes in cell bioenergetics.
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Title: Creating Opportunities for Learning for English Learners with Disabilities Through Quality Individualized Education Programs
Creator: Paul, Jennifer Maria
Date: 2022
Collection: Electronic Theses & Dissertations
Description: Understanding the needs of students who are English learners (ELs) and are also students with disabilities has become an area of policy and research in recent years. Uncovering the needs of this student group requires a closer examination and understanding of the Individualized Education Program (IEP). The IEP is a foundational process and document used by all educators of students identified as students with disabilities to help inform those students’ education. The IEP defines everything...
Show moreUnderstanding the needs of students who are English learners (ELs) and are also students with disabilities has become an area of policy and research in recent years. Uncovering the needs of this student group requires a closer examination and understanding of the Individualized Education Program (IEP). The IEP is a foundational process and document used by all educators of students identified as students with disabilities to help inform those students’ education. The IEP defines everything from a student’s current abilities to their goals and even identifies educators’ plans for instruction and support. The IEP is the ‘road map’ for students’ classroom experiences. But what should be included in the ‘road map’ for students with disabilities that are also ELs? The need to answer this question is of great importance as there is currently no guidance from the Michigan Department of Education for Michigan educators on this topic. It is likely that because of an absence of this magnitude that students would bear the brunt of its absence. The negative repercussions come in the form of a potential lack of students’ learning opportunities specific to their needs as English learners. Through the use of the opportunity to learn (OTL) framework developed by Kurtz and Elliott (2011) my research investigates how educators can improve a student’s OTL within the IEPs they conduct and write. My dissertation explores the barriers educators experience as they develop IEPs for this group of students. It will also consider when educators should include EL’s specific needs within the IEP. The study will also recommend that educators use a tool created through my research to improve OTL for ELs with disabilities within the IEPs on which they work.
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Title: Progress toward chemical identification of the sea lamprey (Petromyzon marinus) alarm cue
Creator: Mensch, Emily Lauren
Date: 2022
Collection: Electronic Theses & Dissertations
Description: This thesis examined the chemical constituents of repellent odors in the sea lamprey (Petromyzon marinus), an invasive fish in the Great Lakes basin, for use in management and conservation. Odors are powerful tools that guide organism’s movement decisions, and repellent odors such as conspecific alarm cues are particularly potent. In chapter one, we investigated the chemistry of the alarm cue through behaviorally guided fractionation. We found substantial avoidance responses to two major...
Show moreThis thesis examined the chemical constituents of repellent odors in the sea lamprey (Petromyzon marinus), an invasive fish in the Great Lakes basin, for use in management and conservation. Odors are powerful tools that guide organism’s movement decisions, and repellent odors such as conspecific alarm cues are particularly potent. In chapter one, we investigated the chemistry of the alarm cue through behaviorally guided fractionation. We found substantial avoidance responses to two major fractions: water-soluble and chloroform soluble and a full avoidance response upon recombination of the two fractions. We found no consistent avoidance patterns to subfractions, or individual compounds identified in the water-soluble fraction, and we found no avoidance response to all 32 identified compounds from the water-soluble fraction when combined at observed ratios in the skin. In chapter two, we investigated the role of a potential repellent molecule, putrescine, on sea lamprey activity and avoidance in a small individual behavioral assay and avoidance in a large, multi-animal assay. We found a context-dependent response, where sea lamprey did not increase activity in the small assay but did show a substantial avoidance response to putrescine. No evidence of avoidance to putrescine was observed in the large assay. In sum, these results suggest the alarm cue is likely not contained in the 32 identified compounds in the water-soluble-fraction alone and that the behavioral response to putrescine is context dependent. While elucidating the chemistry of the sea lamprey alarm cue may be more difficult than through behaviorally guided fractionation alone, the continued pursuit is worthwhile because of the utility in invasive species management and conservation of native species.
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Title: Topological Data Analysis and Machine Learning Framework for Studying Time Series and Image Data
Creator: Yesilli, Melih Can
Date: 2022
Collection: Electronic Theses & Dissertations
Description: The recent advancements in signal acquisition and data mining have revealed the importance of data-driven tools for analyzing signals and images. The availability of large and complex data has also highlighted the need for investigative tools that provide autonomy, noise-robustness, and efficiently utilize data collected from different settings but pertaining to the same phenomenon. State-of-the-art approaches include using tools such as Fourier analysis, wavelets, and Empirical Mode...
Show moreThe recent advancements in signal acquisition and data mining have revealed the importance of data-driven tools for analyzing signals and images. The availability of large and complex data has also highlighted the need for investigative tools that provide autonomy, noise-robustness, and efficiently utilize data collected from different settings but pertaining to the same phenomenon. State-of-the-art approaches include using tools such as Fourier analysis, wavelets, and Empirical Mode Decomposition for extracting informative features from the data. These features can then be combined with machine learning for clustering, classification, and inference. However, these tools typically require human intervention for feature extraction, and they are sensitive to the input parameters that the user chooses during the laborious but often necessary manual data pre-processing. Therefore, this dissertation was motivated by the need for automatic, adaptive, and noise-robust methods for efficiently leveraging machine learning for studying images as well as time series of dynamical systems. Specifically, this work investigates three application areas: chatter detection in manufacturing processes, image analysis of manufactured surfaces, and tool wear detection during titanium alloys machining. This work’s novel investigations are enabled by combining machine learning with methods from Topological Data Analysis (TDA), a relatively recent field of applied topology that encompasses a variety of mature tools for quantifying the shape of data. First, this study experimentally shows for the first time that persistent homology (or persistence) from TDA can be used for chatter classification with accuracies that rival existing detection methods. Further, the efficient use of chatter data sets from different sources is formulated and studied as a transfer learning problem using experimental turning and milling vibration signals. Classification results are shown using comparisons between the TDA pipeline developed in this dissertation and prominent methods for chatter detection. Second, this work describes how to utilize TDA tools for extracting descriptive features from simulated samples generated using different Hurst roughness exponents. The efficiency of the feature extraction is tested by classifying the surfaces according to their roughness level. The resulting accuracies show that TDA can outperform several traditional feature extraction approaches in surface texture analysis. Further, as part of this work, adaptive threshold selection algorithms are developed for Discrete Cosine Transform, and Discrete Wavelet Transform to bypass the need for subjective operator input during surface roughness analysis. Both experimental and synthetic data sets are used to test the effectiveness of these two algorithms. This study also discusses a TDA-based framework that can potentially provide a feasible approach for building an automatic surface finish monitoring system.Finally, this work shows that persistence can be used for tool condition monitoring during titanium alloys machining. Since, in these processes, the cutting tools typically fracture catastrophically before the gradual tool wear reaches the maximum tool life criteria, the industry uses very conservative criteria for replacing the tools. An extensive experiment is described for relating wear markers in various sensor signals to the tool condition at different stages of the tool life. This work shows how, in this setting, TDA provides significant advantages in terms of robustness to noise and alleviating the need for an expert user to extract the informative features. The obtained TDA-based features are compared to existing state-of-the-art featurization tools using feature-level data fusion. The temporal location of the most representative tool condition features is also studied in the signals by considering a variety of window lengths preceding tool wear milestones.
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Title: THE ORIGINATION AND IMPLEMENTATION OF THE NATIONAL WETLANDS POLICY OF UGANDA : ENVIRONMENT, KNOWLEDGE, AND POWER FROM THE LATE NINETEENTH CENTURY TO PRESENT
Creator: Doyle-Raso, John
Date: 2022
Collection: Electronic Theses & Dissertations
Description: In the 1980s, following widespread environmental and intellectual changes associated with “swamp reclamation” that in Uganda had started in the early twentieth century, proponents of the emerging science of “wetland conservation” sought to influence the practices and thinking of people across the country. To do so, they created a national wetlands policy based on decentralized “community-based” projects. Yet, farmers’ and investors’ engagements with reclamation have continued. Meanwhile, the...
Show moreIn the 1980s, following widespread environmental and intellectual changes associated with “swamp reclamation” that in Uganda had started in the early twentieth century, proponents of the emerging science of “wetland conservation” sought to influence the practices and thinking of people across the country. To do so, they created a national wetlands policy based on decentralized “community-based” projects. Yet, farmers’ and investors’ engagements with reclamation have continued. Meanwhile, the Ugandan wetlands policy became internationally influential for its groundbreaking approach to interdisciplinary questions about governance, emphasizing economic analyses based on concepts such as “ecosystem services” and “Environmental Economic Valuation.” Ugandan wetland conservationists have had more influence abroad than domestically, as in Uganda neoliberalization and recentralization have limited the power of the community-based groups who have worked through the national policy. Using a range of sources including but not limited to archives and interviews with conservationists, this dissertation historicizes the Ugandan wetlands conservation policy. It comprises two parts addressing overlapping time periods. The first three chapters consider the origination of this policy by analyzing environmental and intellectual changes in southeastern and southwestern Uganda, leading to the creation in the late-twentieth century of environmental regulations. The latter three chapters examine how conservationists have tried implementing the policy in rural and urban places, and in relation to the national emblem of Uganda – the Grey Crowned Crane. They have focused their efforts on community-based projects outside Protected Areas promoting indigenous knowledges and practices to obtain economic benefits from wetlands that conservationists. This approach was an early manifestation of connected trends in international developmentalist networks. Furthermore, the limitations on its implementation have become pivotal in the global histories of neoliberalization, decentralization, and recentralization. Historicizing Ugandan wetland conservationism contributes to four scholarly literatures. 1) Analyzing community-based projects outside “Protected Areas” advances the historiographies of conservation and watershed management in Africa by considering the significances of neoliberalization, decentralization, and recentralization beyond extraordinary legal cases. 2) Examining intellectual changes in this history – including an emphasis on community-based projects, use of the concept of ecosystem services, and the promotion of indigenous knowledges and sciences – reveals connections between changes in environmental science and global trends in developmentalism. 3) Focusing on these changes in Uganda builds on analyses of environmental management in political power there by identifying the importance of an underexamined resource in entrenched land conflicts, and by uncovering early institutional bases of recentralization. 4) Because Ugandan wetland conservationists were global leaders in policy creation, citizen science, and more changes in scientific thinking, researching their work reveals how African scientists have navigated tensions between their local, national, and international interlocutors to become internationally influential. Studying the history of Ugandan wetland conservationism reveals how different people’s engagements with changes in environmental thinking have reshaped environments and livelihoods, as well as influenced international scientific networks.
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Title: Evaluating The Suitability Of Salvaged Lumber As Feedstock In Cross-Laminated Timber
Creator: Abdul Azeez, Ahamed
Date: 2022
Collection: Electronic Theses & Dissertations
Description: Structural abandonment has been a growing concern in the United States for the past few decades. Conventional demolition procedures exercised to eliminate the abandoned structures result in wood waste that are not feasible for reuse. On the other hand, the demand for lumber has been steadily increasing. This research focuses on promoting deconstruction, obtaining the salvaged lumber from deconstructed abandoned buildings, and evaluating the possibility of reusing it to make way for a...
Show moreStructural abandonment has been a growing concern in the United States for the past few decades. Conventional demolition procedures exercised to eliminate the abandoned structures result in wood waste that are not feasible for reuse. On the other hand, the demand for lumber has been steadily increasing. This research focuses on promoting deconstruction, obtaining the salvaged lumber from deconstructed abandoned buildings, and evaluating the possibility of reusing it to make way for a secondary means of lumber production.The study evaluates the engineering properties of salvaged lumber. Furthermore, the salvaged lumber is partially used to manufacture Cross Laminated Timber (CLT) per the current standards and its properties are compared against the properties of CLT panels exclusively made of freshly sawn lumber. By developing variables for the study, the various factors affecting the properties are analyzed. The researcher believes that the intended results would inaugurate the consideration of salvaged wood usage in wood products that serve as construction material.
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