Digital Commons Network^™

Performance Characterization And Optimization Of A Point-Cloud-Based Path Planner In Off-Road Terrains, Casey D. Majhor

Dissertations, Master's Theses and Master's Reports

In this dissertation, I present a multifaceted study on the generation of artificial terrains using a multifractal method, and their use in autonomous ground vehicle (AGV) planning and navigation performance characterization in high-fidelity simulations, and automated parameter optimization.

My first contribution is a multifractal artificial terrain generation method leveraging the 3D Weierstrass-Mandelbrot function to control terrain roughness. We generate 60 unique off-road terrains while varying the fractal dimension and test the impact on vehicle traversal difficulty. Results show that increasing the fractal dimension decreases low-roughness areas, increases semi-rough and high-roughness areas, and decreases vehicle success rates while increasing vertical accelerations, …

Modeling Pulsatile Flows Using Truly Incompressible Finite Volume Lattice Boltzmann Model, Akshay S. Dongre

Dissertations, Master's Theses and Master's Reports

The present study addresses the compressibility error inherent in the standard Lattice Boltzmann Method (LBM) and LBM’s restriction to uniform Cartesian meshes. To mitigate the compressibility error, an incompressible LBM (iLBM) model has been incorporated into the finite volume framework using a cell-centered finite volume approach, leveraging the simplicity of the LBM algorithm for irregularly shaped flow domains with unstructured meshes. Monotonic Upstream-centered Scheme for Conservation Laws (MUSCL) and linear reconstruction (LR) schemes have been used to compute convective fluxes across the cell interfaces with boundary conditions implemented using the second-order accurate Non-Equilibrium Extrapolation (NEE) method.

The finite volume iLBM …

Sustainable Materials For Environment − Multifunctional Material Made From Dead Leaves And Nanostructured Materials For Antibiotic Degradation, Siyuan Fang

Dissertations, Master's Theses and Master's Reports

As environmental pollution from industrial processes and human activities continues to rise, finding efficient approaches to recycle waste materials and degrade persistent contaminants becomes increasingly critical. Dead leaves, an abundant but underutilized biomass, present an opportunity for creating value-added materials if their biocomponents can be preserved and transformed. Simultaneously, antibiotics such as tetracycline are widely found in water bodies but pose serious ecological and health risks, necessitating effective degradation methods. This dissertation addresses these challenges by leveraging natural and nanostructured materials to develop multifunctional products and advanced photocatalytic processes.

Chapter 3 of this dissertation addresses the challenge of converting waste …

Phase Field Modeling Of Fracture And Phase Separation Using Numerical Methods And Machine Learning, Revanth Mattey

Dissertations, Master's Theses and Master's Reports

Phase field modeling is a crucial tool in scientific and engineering disciplines due to its ability to simulate complex phenomena like phase transitions, interface dynamics, and pattern formation. It plays a vital role in understanding material behavior during processes such as solidification, phase separation, and fracture mechanics. Particularly in fracture mechanics, phase field modeling can be utilized to predict the crack path in complex materials. Understanding the failure behavior is vital for applications of any material. The specific contributions to the field of phase field fracture mechanics, are, Firstly, we propose a novel phase field fracture model to simulate the …

Investigating Microphysical Variability And Entrainment In Clouds Using Airborne Digital Holography, Machine Learning, And Large Eddy Simulations, Nithin Allwayin

Dissertations, Master's Theses and Master's Reports

Advancing our understanding of cloud microphysics—the processes governing cloud particles' formation, growth, and interactions—is essential for accurate weather and climate modeling. In this work, we investigate how droplet size distributions vary in a cloud and explore how microphysical properties such as droplet size and number concentration respond to entrainment and mixing.

In the first part of the work, a novel algorithm is developed combining hypothesis testing with density-based clustering to identify characteristic cloud droplet size distribution types in marine stratocumulus clouds. Applied to data from the airborne Holographic Detector for Clouds (HOLODEC), the algorithm successfully identifies a relatively small set …

Synthesis Of Long Oligodeoxynucleotides, Yipeng Yin

Dissertations, Master's Theses and Master's Reports

Synthetic long oligodeoxynucleotides (ODNs) have found wide applications in diverse fields such as chemical biology, synthetic biology, and genes and genomes synthesis. Those applications leading to a significant demand for their production. However, traditional methods for purifying synthetic ODNs present notable drawbacks, particularly their inability to purify long ODNs, rendering long ODN synthesis challenging. To address these issues, chemical synthesis techniques for long ODNs coupled with non-chromatographic purification methods have been developed. This technology makes the purification of long synthetic ODNs feasible and offers a viable pathway for producing genes and genomes with extensive repeats or stable secondary structures, which …

Understanding Catalyst Design Principles In Transition Metal Mixed Anionic Chalcogenides For Electrocatalytic Energy Conversion, Ibrahim Abdullahi

Doctoral Dissertations

"This research focused on the synthetic design of transition metal mixed anionic chalcogenide catalysts containing various ligand types around the central metal atom (chalcogen anion and chalcogen-based organic ligand) generating diverse crystal structure types applied for water splitting and carbon dioxide reduction reactions (CO₂RR).

A series of catalysts were synthesized starting with isolated metal complexes (ME_n) with a central metal core (M = Co, Ni, Cu, and Cr) through molecular clusters, to bulk nanostructured solids of similar M-E coordination. Bis(dichalcogenoimidodiphosphinato) were employed as ligands in the metal complexes, and anionic chalcogen (E = S, Se, and …

Development And Testing Of High Strength Scalable High Entropy Alloys, Hans Jakob Pommerenke

Doctoral Dissertations

"High entropy alloys have shown promise through their ability to be tailored to specific scenarios. From highly corrosive environments to precipitation strengthened alloys to radiation environments high entropy alloys allow tailor made alloys for every solution. New compositions are developed and tested but little work focuses on the processing effect choosing rather than using processing as a steppingstone to achieve properties without investigating the processing effects. This work focuses on single phase face-centered cubic alloys strengthened by processing and precipitation strengthening. In conjunction with the development of these alloys, the ability to scale production will be investigated and characterized to …

Low-Shrinkage Fiber-Reinforced Concrete For Infrastructure Construction And Rehabilitation, Jingjie Wei

Doctoral Dissertations

"The aim of this study is to develop two classes of low-shrinkage high-performance concrete (HPC): fiber-reinforced super workable concrete (FR-SWC) for infrastructure construction and fiber-reinforced self-consolidating concrete (FR-SCC) for repair applications. HPC with excess content of shrinkage mitigation materials (SMMs), including shrinkage-reducing admixture (SRA), superabsorbent polymer (SAP), and expansive agent (EA) has a detrimental effect on mechanical performance. These classes of HPC were optimized to reduce shrinkage, enhance mechanical properties, and improve durability. The effect of fiber type (macro synthetic fiber, MSF; 5D steel fiber, 5D; 80% 3D + 20% short steel fibers; STST), SMMs, and plastic viscosity on bond …

Additive Manufacturing Of Steel And Aluminum Structures: Modeling And Experiments, Manoj Kumar Reddy Rangapuram

Doctoral Dissertations

"Additive manufacturing (AM) is defined as the process of joining materials to make objects from three-dimensional model data. Complex geometries can be easily manufactured compared to conventional subtractive methods with more freedom and flexibility in the design process. As the demand for AM process increased, it has become critical to understand the process and various parameters that constitute in affecting the quality of the manufactured part. Conducting experiments can be time intensive and costly to optimize a process. Modeling can be used as an aid to optimize, examine, and predict the process outcome.

The objective of this study is (i) …

การตีความข้อยกเว้นด้านความมั่นคงมาตรา Xxi(B) ขององค์การการค้าโลก, นิธินันท์ ลีธนะกุล

Chulalongkorn University Theses and Dissertations (Chula ETD)

ข้อยกเว้นด้านความมั่นคงตามมาตรา XXI(b) แห่งความตกลงองค์การการค้าโลก (WTO) ทวีความสำคัญขึ้นในปัจจุบัน เนื่องจากประเทศสมาชิกนำมาใช้เป็นเครื่องมือจำกัดการค้าระหว่างประเทศมากขึ้น การศึกษานี้มุ่งวิเคราะห์การตีความและการบังคับใช้ข้อยกเว้นดังกล่าว โดยเปรียบเทียบกับบทบัญญัติมาตรการที่กระทำได้ (Non-Precluded Measures Clause: NPM) ในกฎหมายการลงทุนระหว่างประเทศ โดยตั้งสมมติฐานว่าการพิจารณาเพียงเงื่อนไขตาม (i)-(iii) ของมาตรา XXI(b) เป็นเกณฑ์ที่อาจทำให้ประเทศสมาชิกยกอ้างข้อยกเว้นความมั่นคงได้โดยง่ายเกินไป การศึกษาใช้วิธีวิจัยเชิงเอกสารโดยวิเคราะห์คำวินิจฉัยของคณะกรรมการระงับข้อพิพาทของ WTO คำชี้ขาดของคณะอนุญาโตตุลาการด้านการลงทุนระหว่างประเทศ ตลอดจนประวัติการเจรจาและวัตถุประสงค์ของมาตรา XXI ผลการศึกษาพบว่า WTO ยังขาดกฎเกณฑ์ที่ชัดเจนในการตรวจสอบการใช้ดุลพินิจของรัฐ แม้ไม่อาจนำกฎเกณฑ์ของกฎหมายการลงทุนระหว่างประเทศมาใช้โดยตรงเนื่องจากลักษณะธุรกรรมและความสัมพันธ์ที่แตกต่างกัน แต่มีส่วนที่สอดคล้องกันคือการใช้วลี "it considers necessary" ที่สะท้อนลักษณะบทบัญญัติแบบอัตวินิจฉัย (self-judging) ทั้งนี้ แนวปฏิบัติจากกฎหมายการลงทุนระหว่างประเทศสามารถนำมาประยุกต์ใช้ในการตรวจสอบการใช้ดุลพินิจของรัฐภายใต้กรอบ WTO ในส่วนของหลักสุจริตได้ อย่างไรก็ตาม ความกังวลสำคัญคือการใช้ข้อยกเว้นด้านความมั่นคงในทางที่ผิดอย่างต่อเนื่อง อาจทำให้ข้อยกเว้นกลายเป็นหลักปฏิบัติปกติ ซึ่งทำลายเจตนารมณ์ดั้งเดิมและส่งผลกระทบต่อเสถียรภาพของระบบการค้าระหว่างประเทศ การศึกษานี้จึงเสนอแนะให้พัฒนาแนวทางการตีความที่ชัดเจนขึ้น สร้างกลไกการตรวจสอบที่มีประสิทธิภาพ และสร้างความสมดุลระหว่างการคุ้มครองผลประโยชน์ด้านความมั่นคงของรัฐและการรักษาเสถียรภาพของระบบการค้าระหว่างประเทศ

Disciplining The Responses To Cross-Border Subsidies: The Case Study Of Eu And Us Trade Remedy Investigations Against Products From Indonesia And Thailand, Jia Zhen Cen

Chulalongkorn University Theses and Dissertations (Chula ETD)

The geopolitical confrontation between the United States and China extends across various levels and domains, with trade being one of the most prominent arenas. Subsidies, a longstanding source of contention in international trade, have become an even more contentious issue following China’s launch of the Belt and Road Initiative (BRI) in 2013. Traditionally, subsidies are provided by a government to its domestic producers, and WTO subsidy rules allow its Members to take countervailing measures against subsidies of their direct trading partners when those subsidies cause injury to the Member's domestic industries. However, the rise in cross-border subsidies – where governments …

The Dynamics Of The Chana Community Network Movement: Strategic Shifts, Impacts, And Reflections On Thailand's Political Landscape, Abdullah Yuhannan

Chulalongkorn University Theses and Dissertations (Chula ETD)

This dissertation examines the dynamics of the Chana Community Movement, one of Thailand’s most enduring grassroots movements. Originating in the early 1990s with opposition to illegal commercial fishing, the movement has evolved to resist the Chana Industrial Estate Project. The research addresses key questions concerning factors sustaining the movement, tactical adaptations, societal impacts, and its reflection of Thailand’s contemporary political landscape. The study employs a qualitative research methodology, combining document analysis, in-depth interviews, and participant observation, alongside analytical frameworks derived from political struggle studies and social movement theories for comprehensive analysis. The findings reveal that the Chana Community Movement succeeded …

Understanding Pluriversal Ontology: The Cases Of Three Alternative Agriculture Communities In Sisaket Province, Northeastern, Thailand, Thita Ornin

Chulalongkorn University Theses and Dissertations (Chula ETD)

In reaction to the global development paradigm, the concept of Pluriverse has played a pivotal role in exploring alternatives to development, aiming to foster a world that accommodates multiple worlding with the goals to facilitate various approaches to collective well-being, moving away from anthropocentric, linear growth within the modern capitalist development. This thesis seeks to understand alternative agriculture cases in the Northeast of Thailand through the Pluriversal ontology conceptual framework and to determine its usefulness through the following proposed framework; (1) alternative agricultural development discourse analysis, (2) friction and assimilation with modernity and (3) post-development values. Taken an inspiration from …

Thailand's Never-Ending Pesticide Debate: Contested Future Sociotechnical Imaginaries Through A Relational Co-Productionist Lens, Henriette Erawan Kamphorst

Chulalongkorn University Theses and Dissertations (Chula ETD)

Since the introduction of the Green Revolution, the use of agrochemicals in Thai farming has sparked repeated contentious debates among local policy elites, addressing issues such as consumer health, farmer livelihoods, and environmental degradation. In 2019, this subject re-emerged on the policy agenda with the proposed ban of three key agrochemicals: Chlorpyrifos, Paraquat, and Glyphosate. In order to understand why the pesticide issue has remained on policy actors’ agendas for so long and still continues to be subject to ongoing debate, this research takes on a new perspective by adopting a relational co-productionist approach in the construction of contesting sociotechnical …

Private Motorcycle Users' Insights Toward Public Bus Adoption In Phnom Penh, Eangthay Tang

Chulalongkorn University Theses and Dissertations (Chula ETD)

As Phnom Penh experiences rapid population growth and economic expansion, traffic congestion has worsened, largely due to the increasing ownership of private motorcycles. Despite the introduction of public bus services, adoption remains low as concerns over service quality, limited coverage, and inadequate infrastructure deter motorcycle users from making the shift. This study investigates the behavioral intentions, preferences, and concerns of motorcycle users, specifically targeting university students, to understand how public bus services can be improved to encourage adoption. Data were collected in July 2024 from 457 university students who regularly use motorcycles, using a structured questionnaire across four Phnom Penh …

The Effects Of Uv-Radiation On The Removal Of Microplastics In Water Using Agglomeration-Micro-Flotation, Palot Srichonphaisarn

Chulalongkorn University Theses and Dissertations (Chula ETD)

Microplastics, plastic particles with diameter 1 micrometer to 5 millimeters, can disturb marine ecosystems due to their small size and surface properties which can be a carrier for hazardous matters. While wastewater treatment plants could remove some microplastics but some of them remain. Among the various removal techniques, flotation is a potential method due to the hydrophobic nature of microplastics. This study investigates the effects of ultraviolet radiation on the surface wettability of microplastics and removal efficiency of microplastics. The 6 types of microplastics were prepared from plastic boards. After the ultraviolet radiation, the results showed that ultraviolet radiation could …

Exploring Microplastics In Seawater And Zooplankton On The Eastern Coast Of Thailand: A Case Study In Phuket Province, Pensiri Akkajit, Sirima Yuankerd, Arsanchai Sukkuea

Applied Environmental Research

Microplastics can accumulate in the environment and be transferred to different trophic levels, making them a concern for the aquatic food chain. As far as the researcher is aware, this study is the first to analyze microplastics in seawater and zooplankton along the eastern coastline of Phuket, Thailand, emphasizing their ecological significance. Analysis of the seawater samples identified 256 microplastic particles, with an average concentration of 52.6±21.4 and 32.6±30.3 particles L-1 for 20–300 µm and >300 µm classes, respectively. Four zooplankton species—copepod, fish larvae, bivalvia larvae, and shrimp larvae—were chosen for examination. The findings indicated that microplastics can move to …

Prevalence Of Microplastics In Coastal Area Of Samae San, Thailand And Its Possible Source, Siwanath Pangpunth, Sujaree Bureekul, Voranop Viyakarn

Applied Environmental Research

This research explored the abundance, morphology, and polymer composition of microplastics (MPs) in various environmental samples within the Samae San subdistrict involving surface soil nearby the dumping site, road dust soil, beach sand and sediment in the area with distinct land- based activities. Dumping site soil exhibited the highest concentration in items per kg of dry weight at 93,734.3, followed by road dust soil (573.0 ± 583.7), beach sand (99.8 ± 75.3), and sediment (83.1 ± 50.4). Morphological traits revealed similarities between transparent fiber-shaped particles in beach sands and sediment, and those in nearby road dust soil, while green sheet-shaped …

Removal Of Chromium From Aqueous System Using Nanocellulose Prepared From Defoliated Terminalia Catappa Leaves, Lopamudra Digal, Jayashree Mohanty

Applied Environmental Research

Nanocellulose is considered as a sustainable and renewable nanomaterial due to its abundant availability, biodegradability and biocompatibility characteristics. The study demonstrates the synthesis of nanocellulose from defoliated leaves of the Tropical Almond (Terminalia catappa) plant, abundantly available residual plant biomass and its subsequent use in eliminating Cr(VI) from the water system. The study demonstrates the preparation of nanocellulose by chemical means, employing NaOH and H2SO4 as chemical agents. Characterization techniques like FTIR, SEM, and XRD were used to study the chemical composition and morphology of the resulting nanocellulose. The characterization studies confirm the formation of nanocellulose from the plant biomass. …

Exploring Google Earth Engine, Machine Learning, And Gis For Land Use Land Cover Change Detection In The Federal Capital Territory, Abuja, Between 2014 And 2023, Akus Kingsley Okoduwa, Chika Floyd Amaechi

Applied Environmental Research

This study aims to visualize various land use land cover (LULC) classes, estimate the net change in LULC types between the years 2014 and 2023, and use transition mapping to track LULC transitions within waterbody, vegetation, bareland, and buildup to better understand how land use types change from one another. Google Earth Engine (GEE), Random Forest (RF), and Geographic Information System (GIS) were used for LULC classification and change detection. The dataset employed for this study is Landsat-8 with 30 m resolution, and four land cover classes, which include waterbody, vegetation, bareland, and buildup, were classified for this study using …

Spatiotemporal Patterns Of Land Surface Temperature, Urban Heat Island, And Potential Heat Stress Risk Areas Assessment For Tropical Inland City And Coastal City In Thailand, Thar Htet Aung, Sakpod Tongleamnak, Rasamee Suwanwerakamtorn

Applied Environmental Research

Global warming and rapid urban growth, compounded by the urban heat island (UHI) effect, are posing substantial challenges for urban populations and ecological well-being due to increased heat stress risks. This study aimed to analyze the spatiotemporal patterns of land surface temperature (LST), UHI, and potential heat stress risk areas (PHSRA) in two distinct cities, an inland city, Nakhon Ratchasima, and a coastal city, Si Racha, during the summer. Geoinformatics techniques and Crichton’s Risk Triangle method were employed, using updated demographic data and Sentinel-3 data from 2017 to 2022. The findings indicate that the inland city daytime average LST values …

Geospatial Modelling Of Flood Susceptibility Of The Calabar City, Cross River State, Nigeria, Joel Efiong, Eme Efiong, Oluyemi Akintoye, Ebin Inah, Obianuju Awan, Francis Ogban

Applied Environmental Research

Flooding remains a major environmental problem in many parts of the world including Nigeria, causing untold losses. This study modelled the flood susceptibility of Calabar Metropolis using frequency ratio and geographical information system (GIS). Direct field observation and key informant approaches were used to obtain 127 previous and current flood locations in the study area from which a database of historical flood occurrence was developed. Using the geostatistical analyst tool within a geographical information environment the flood locations were split into two parts in the ratio of 70:30 percent for the training and testing processes, respectively. Eight flood conditioning factors …

Market Failure And Censorship In The Marketplace Of Ideas, John P. Anderson, Jeremy Kidd

Oklahoma Law Review

No abstract provided.

Tesla, Let Me Fix My Car: The Right To Repair And The Need For A Balance Between Public And Private Enforcement, Emanuele S. Putrino

Oklahoma Law Review

No abstract provided.

Prioritizing Oklahoma Mothers: Recommending Rehabilitation And Recovery Rather Than Punishment For Pregnancy, Alex B. Cox

Oklahoma Law Review

No abstract provided.

Re/Descheduling Marijuana Through Administrative Action, Scott Bloomberg, Alexandra Harriman, Shane Pennington

Oklahoma Law Review

No abstract provided.

After Affirmative Action: Contextual Admissions And The Future Of African American Law School Enrollment, Nathan L. Bennett Fleming

Oklahoma Law Review

No abstract provided.

The Nation’S Transfer Tax Regime And The Tax Gap, Jay A. Soled

Oklahoma Law Review

No abstract provided.

Interpolation, Litigation, And Copyright Confusion: How The Music Industry’S Influence Is Hindering Creativity, Hannah Edmondson

Oklahoma Law Review

No abstract provided.