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Articles 14551 - 14580 of 198032

Full-Text Articles in Engineering

Experimental Investigation Of Surfactant Impact On Surfactant-Oil-Brine System For Surfactant Enhanced Oil Recovery, Chananpat Worpattanaluk Jan 2025

Experimental Investigation Of Surfactant Impact On Surfactant-Oil-Brine System For Surfactant Enhanced Oil Recovery, Chananpat Worpattanaluk

Chulalongkorn University Theses and Dissertations (Chula ETD)

Enhanced Oil Recovery (EOR) is a vital technique for improving hydrocarbon extraction efficiency from mature or low-production reservoirs. Among various EOR methods, chemical flooding, particularly surfactant-based EOR, has gained attention due to its ability to reduce interfacial tension (IFT), to alter rock wettability, and to mobilize trapped oil. However, the performance of surfactant systems is highly sensitive to reservoir salinity, temperature, and rock-fluid interactions, leading to surfactant precipitation, adsorption losses, and interfacial tension reduction. Therefore, understanding the effects of salinity, surfactant concentration, and the role of scale inhibitors on the physicochemical stability of surfactant-oil-brine systems is essential for designing robust …

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Enhancing Performance Of Lstm For Water Level Forecasting In Lower Mekong River With Feature Selection Strategy, Chanreng Sey Nhim Jan 2025

Enhancing Performance Of Lstm For Water Level Forecasting In Lower Mekong River With Feature Selection Strategy, Chanreng Sey Nhim

Chulalongkorn University Theses and Dissertations (Chula ETD)

This study addresses key research gaps, including the lack of systematic feature selection, structured hyperparameter optimization, and comprehensive long-term and cross-location performance evaluation in the Lower Mekong River Basin to enhance the water level forecasting performance. The research has utilized a Vanilla Long Short-Term Memory (LSTM) network trained on 22 years of historical water level data from the Mekong River Commission (MRC) and 16 localization meteorological features from Open-Meteo. The methodology uses Grid Search optimization for hyperparameter tuning and employs the Spearman rank correlation coefficient as a filter feature selection technique to identify relevant input variables and minimize redundancy. Performance …

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Efficient Photocatalytic Hydrogen Evolution Via Novel Syntheses Of Srtio₃/G-C₃N₄ Heterojunction Photocatalysts, Chiramet Thatsanakunlaphan Jan 2025

Efficient Photocatalytic Hydrogen Evolution Via Novel Syntheses Of Srtio₃/G-C₃N₄ Heterojunction Photocatalysts, Chiramet Thatsanakunlaphan

Chulalongkorn University Theses and Dissertations (Chula ETD)

Strontium titanate/graphitic carbon nitride (SrTiO3/g-C3N4) heterojunctions are widely used as photocatalysts. However, traditional multistep synthesis methods for these photocatalysts often involve complexity, long processing times, and high energy consumption. To address these issues, a systematic comparison of various simplified synthesis approaches was conducted, emphasizing the influence of synthesis parameters on the structural properties and hydrogen evolution performance. Six comparative studies were conducted to illustrate the roles of solvent choice, thermal post-treatment, and synthesis route. Results showed that ethylene glycol consistently produced more active photocatalysts than ethanol in both one-pot and two-step solvothermal methods. Non-calcined samples exhibited superior hydrogen evolution activity …

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Quality Of Life Prediction For Driving Route Planning System Using Image Recognition And Deep Learning, Intouch Prakaisak Jan 2025

Quality Of Life Prediction For Driving Route Planning System Using Image Recognition And Deep Learning, Intouch Prakaisak

Chulalongkorn University Theses and Dissertations (Chula ETD)

Assessing travel-related Quality of Life (QoL) is a significant challenge due to its reliance on subjective human perception, which is difficult to measure. Traditional studies are often constrained by the limited scope of costly, manual data collection. The significant contribution of this research is the introduction of a new framework that can analyze tourist perception on a large and systematic scale. The novelty of this work lies in the utilization of Google Street View (GSV) as a large-scale visual data source, coupled with the use of a sequence-based model to analyze travel routes, which allows for the simulation of the …

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Improving The Availability Of Aluminium Sheath Extrusion Machines In The Cable Industry, Jirathana Vasinyont Jan 2025

Improving The Availability Of Aluminium Sheath Extrusion Machines In The Cable Industry, Jirathana Vasinyont

Chulalongkorn University Theses and Dissertations (Chula ETD)

Aluminium sheath extrusion machines (AL Seamless) play a critical role in the production of high-voltage cables, ensuring the integrity and quality of electrical transmission infrastructure. However, after commissioning such machines at PD Company was fraught with challenges, including frequent breakdowns, limited machine availability, and production inefficiencies. The underlying issues stemmed from inadequate standard operating procedures (SOPs), insufficient knowledge transfer during commissioning, and suboptimal maintenance practices. To address these challenges, this research applied structured methodologies, including Failure Mode and Effects Analysis (FMEA) to identify critical failure points and root causes, and Total Productive Maintenance (TPM) to improve operational reliability. Knowledge transfer …

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Out-Of-Domain Tuberculosis Detection From Chest X-Ray Images Using Meta Learning With Soft Labels, Kanokphat Jinanarong Jan 2025

Out-Of-Domain Tuberculosis Detection From Chest X-Ray Images Using Meta Learning With Soft Labels, Kanokphat Jinanarong

Chulalongkorn University Theses and Dissertations (Chula ETD)

Automated tuberculosis screening from chest x-ray images could greatly benefit regions with limited medical resources. However, currently available methods could not handle this problem well due to the difference in chest x-ray images in each region caused by the difference in machine and demographics, the possible noise in the available labels, and other reasons. We therefore propose a new machine learning algorithm that could detect tuberculosis with great accuracy on any other data sources by learning from completely different data sources. We used a model-agnostic meta-learning together with a soft label approach, utilizing the meta-gradient to dynamically adjust the soft …

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A Study On The Impact Of Superconducting Fault Current Limiteron Arc Flash Hazard In An Industrial System, Kittipong Anantanasap Jan 2025

A Study On The Impact Of Superconducting Fault Current Limiteron Arc Flash Hazard In An Industrial System, Kittipong Anantanasap

Chulalongkorn University Theses and Dissertations (Chula ETD)

The increasing integration of distributed generation raises short-circuit current levels, which lead to concerns about equipment overheating, insulation deterioration, and system stability issues. The Resistive Superconducting Fault Current Limiter (R-SCFCL) offers an effective solution by dynamically increasing circuit impedance during faults without affecting normal operation. However, its integration may alter the fault-clearing time of the protection system, which is crucial for arc-flash safety. This study evaluates the impact of R-SCFCL integration on arc-flash hazards in an industrial power system, utilizing DIgSILENT PowerFactory and calculations based on IEEE 1584. Results indicate that while the R-SCFCL effectively reduces arcing current, the incident …

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Vehicle Routing Problem With Time Constraint From Multiple Origins To Selective Destinations By Using Genetic Algorithm, Manocha Kruetet Jan 2025

Vehicle Routing Problem With Time Constraint From Multiple Origins To Selective Destinations By Using Genetic Algorithm, Manocha Kruetet

Chulalongkorn University Theses and Dissertations (Chula ETD)

This thesis addresses the vehicle routing problem with time constraints from multiple origins to selective destinations by using a genetic algorithm for efficient path planning. The focus is on optimizing field collection and repossession activities in the financial industry to enhance operational efficiency and customer satisfaction. The proposed approach integrates two main components: a tailored genetic algorithm for multi-objective optimization and a graph neural network for precise travel time estimation. The genetic algorithm is designed to minimize total travel distance or travel time and balance the workload among field collectors, while the graph neural network provides travel time estimates to …

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Development Of Defective Tiox And Hfo2-X For Efficient Visible-Light-Driven Photocatalytic Degradation Of Organic Pollutants, Mohammad Rahim Pour Jan 2025

Development Of Defective Tiox And Hfo2-X For Efficient Visible-Light-Driven Photocatalytic Degradation Of Organic Pollutants, Mohammad Rahim Pour

Chulalongkorn University Theses and Dissertations (Chula ETD)

The development of efficient photocatalysts capable of operating under visible light is critical for addressing persistent organic contaminants in wastewater. In this thesis, two complementary strategies are presented that exploit defect engineering and heterojunction construction to enhance charge separation, light absorption, and pollutant degradation. In the first study, titanium oxide quantum dots with a high density of oxygen vacancies were dispersed onto H-Beta zeolite supports via a sono-deposition approach. The zeolite substrate not only enabled uniform distribution of sub-5 nm TiOx particles, but also promoted pre-accumulation of cationic dyes, which significantly improved their subsequent oxidation. Structural and spectroscopic analyses confirmed …

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Feasibility Study Of Utilization Of Calcium-Based Material For Integrated Methane Dry Reforming And Co2 Absorption-Mineralization Processes, Nattanan Watcharasawat Jan 2025

Feasibility Study Of Utilization Of Calcium-Based Material For Integrated Methane Dry Reforming And Co2 Absorption-Mineralization Processes, Nattanan Watcharasawat

Chulalongkorn University Theses and Dissertations (Chula ETD)

This thesis investigates an integrated absorption-mineralization and dry reforming of methane (IAM-DRM) loop. The aim is to demonstrate the feasibility of using CaCO3 derived from amine scrubbing both as a CO2 sink and as reactive support for in situ Ni activation during DRM, while simultaneously regenerating the MEA solvent and calcium material for repeated use. CO2 absorption of monoethanolamine (MEA) yield equilibrium loadings of 0.66 mol CO2 mol-1 MEA with regenerated MEA maintaining identical performance. Mineralization on CaCl2 and Ca(OH)2 produced different phases product. Temperature programmed DRM demonstrated that mineralized CaCO3 can activate Ni in situ and sustain CH4 conversion. …

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Electrochemical Reduction And Regeneration Of Carbamate, Nattiya Jumpadib Jan 2025

Electrochemical Reduction And Regeneration Of Carbamate, Nattiya Jumpadib

Chulalongkorn University Theses and Dissertations (Chula ETD)

A reliable method for removing carbon dioxide (CO2) gas from industrial emissions involves CO2 absorption into monoethanolamine (MEA) solution to achieve carbon neutrality. However, the regeneration of MEA is costly and still requires heat to release the CO2 that was captured and other processes to manage the CO2 onwards. Our research demonstrates that integrating CO2 capture with electrochemical CO2 conversion reduces regeneration processes and converts CO2 into valuable products. The electrochemical reduction and regeneration of MEA-CO2 adduct (carbamate) were investigated simultaneously by using copper pulse-electrodeposited on copper foils as a cathode in a microchannel reactor. The gas products were analyzed …

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Effect Of Catalyst Bed Configuration On Temperature Profile And Reactor Performance For Fischer-Tropsch Synthesis : A Computational Fluid Dynamics Simulation, Natthasit Khawyen Jan 2025

Effect Of Catalyst Bed Configuration On Temperature Profile And Reactor Performance For Fischer-Tropsch Synthesis : A Computational Fluid Dynamics Simulation, Natthasit Khawyen

Chulalongkorn University Theses and Dissertations (Chula ETD)

This research investigates the performance of the Fischer–Tropsch reaction in a fixed-bed reactor packed with spiral-structured catalysts using COMSOL Multiphysics to evaluate heat management, hot spot reduction, and the enhancement of high-value product selectivity. The study comprises two main scenarios. The first examines the effects of tube spacing and number of tubes in a multitube reactor arranged in a hexagonal pattern using a 20% Co/SiO₂ spiral-structured catalyst. In models R1–R4, which contain a fixed number of 10 tubes, tube spacing was found to have only a limited influence on temperature distribution; all models still exhibited a hot spot near the …

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Performance Evaluation Of Strategic Bandwidth Block Assignment For Interference Reduction In High-Density 5g Nr Cell Environments, Pasapong Wongprasert Jan 2025

Performance Evaluation Of Strategic Bandwidth Block Assignment For Interference Reduction In High-Density 5g Nr Cell Environments, Pasapong Wongprasert

Chulalongkorn University Theses and Dissertations (Chula ETD)

Due to the increasing demand for mobile data, mobile network operators (MNOs) typically rely on cell densification to increase capacity. However, doing so also introduces more inter-cell interference (ICI), leading to lower spectral efficiency and making further capacity enhancements challenging. This thesis explores a bandwidth block assignment method for ICI mitigation. The core idea is to divide the bandwidth of an NR carrier into two partially overlapping bandwidth parts (BWPs) to reduce the impact of ICI. By allowing the two BWPs to share the same synchronization signal block (SSB), the same attach and handover configurations can be applied. A modified …

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Behavior Of Reinforced Concrete Beams With Externally Anchored Rebars, Nyan Soe Lynn Jan 2025

Behavior Of Reinforced Concrete Beams With Externally Anchored Rebars, Nyan Soe Lynn

Chulalongkorn University Theses and Dissertations (Chula ETD)

This study investigates a minimally invasive rehabilitation method for reinforced concrete (RC) beams using externally anchored reinforcement by means of epoxy. Two programs were conducted: flexural rehabilitation using externally anchored longitudinal bars, and shear rehabilitation using externally anchored U-shaped stirrups. Four beam specimens were tested under four-point bending for the flexural program, and four under three-point bending for the shear program. Test results from the flexural program showed large deformation due to plastic hinge formation. Due to their unbonded nature, the external rebars engaged later than the internal reinforcement and developed large deflection. Load-carrying capacity, however, was not increased since …

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Tailoring The Intrinsic Properties Of Polypropylene/Polypropylene Carbonate Blends Using Epoxidized Natural Rubber As A Bio-Based Compatibilizer, Patsita Suphansomboon Jan 2025

Tailoring The Intrinsic Properties Of Polypropylene/Polypropylene Carbonate Blends Using Epoxidized Natural Rubber As A Bio-Based Compatibilizer, Patsita Suphansomboon

Chulalongkorn University Theses and Dissertations (Chula ETD)

The goal of this study was to enhance the biocompatibility of polypropylene/polypropylene carbonate (PP/PP) polymer blends by varying amounts of epoxidized natural rubber (ENR). This study focuses on determining how ENR concentration affects the interface and final properties of the polymer blend. A comprehensive analysis of the physical, mechanical, thermal, chemical, and dynamic mechanical properties, as well as the rheological properties of the PP/PPC system, was conducted to assess structural changes and property evolution within the PP/PPC system. The experimental results revealed that ENR can interact with PPC, resulting in a reduced domain size and a more uniform distribution. This …

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Evaluating Co2 Storage Criteria : Focusing On Thailand's Petroleum Basins For Carbon Storage, Paul Tivere Benjamin Jan 2025

Evaluating Co2 Storage Criteria : Focusing On Thailand's Petroleum Basins For Carbon Storage, Paul Tivere Benjamin

Chulalongkorn University Theses and Dissertations (Chula ETD)

Anthropogenic carbon dioxide (CO2) emissions from large point sources remain central to Thailand’s climate challenge, and geological carbon capture and storage (CCS) is now included in national mitigation plans. However, Thailand still lacks a transparent way to compare candidate saline aquifers and petroleum basins in terms of storage performance, containment, and socio-economic conditions, while allowing for uneven data quality. This thesis develops a Thailand-specific, two-stage framework that combines threshold-based screening with a multi-criteria ranking framework based on the Analytic Hierarchy Process (AHP) and Data Confidence Scores (DCS). Twenty-one criteria in three groups (capacity and injectivity, containment, and socio-economic constraints) were …

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Development Of Self-Healing Polymer From Bio-Based Benzoxazine Blend With Poly(Ethylene Glycol) For Anti-Biofouling Applications, Pharaporn Yodkum Jan 2025

Development Of Self-Healing Polymer From Bio-Based Benzoxazine Blend With Poly(Ethylene Glycol) For Anti-Biofouling Applications, Pharaporn Yodkum

Chulalongkorn University Theses and Dissertations (Chula ETD)

Biofouling remains a significant challenge in marine industries, as conventional coatings often lose their antifouling efficacy once they become damaged. Incorporating self-healing capabilities into antifouling coatings has therefore emerged as a promising strategy to extend service life and maintain long-term performance. In this study, self-healing polymers were developed based on a bio-derived benzoxazine resin (E-fa), synthesized from renewable precursors including eugenol (a phenol source), furfurylamine (an amine source), and paraformaldehyde, and subsequently blended with poly(ethylene glycol) (PEG). The blends were formulated with varying weight ratios (95/5, 90/10, 85/15, and 80/20 wt/wt%) and PEG molecular weights (PEG-600, PEG-1500, and PEG-4000). This …

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Real-Time Monitoring System For Sedentary Behavior Using Pose-Estimation Approach, Pheng Ou Chea Jan 2025

Real-Time Monitoring System For Sedentary Behavior Using Pose-Estimation Approach, Pheng Ou Chea

Chulalongkorn University Theses and Dissertations (Chula ETD)

Long-term sedentary behavior, defined as extended periods of sitting or inactivity, increases the risk of obesity, cardiovascular disease, and other health problems. These risks are often underestimated due to low levels of physical activity. This study proposes the use of You Only Look Once (YOLO)–based pose estimation for dwell-time analysis to monitor sedentary behavior. We examined posture over an entire day to assess prolonged inactivity and encourage individuals to balance energy expenditure with available time—such as engaging in exercise in the early morning or evening according to recommended guidelines. For employees across generations, as well as for vulnerable groups such …

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A Novel Hydrothermal Synthesis Process Of Mil-53(Al) Using Bamboo Biochar As A Sustainable Precursor For Co₂ Adsorption, Pisit Phayutcharoenkun Jan 2025

A Novel Hydrothermal Synthesis Process Of Mil-53(Al) Using Bamboo Biochar As A Sustainable Precursor For Co₂ Adsorption, Pisit Phayutcharoenkun

Chulalongkorn University Theses and Dissertations (Chula ETD)

Among the numerous MOFs members, MIL-53 (Al) framework is one of the most interesting structures due to the breathing effect and has been widely investigated for hydrogen storage and water treatment. It is built up by the interconnection of infinite trans chains of corner-sharing AlO4(OH)2 octahedral by 1,4-benzenedicarboxylate ligands. MIL-53 crystallizes in a “wine rack” structure (Pnma, a = 17.129(2) Å, b = 6.628(1) Å, c = 12.182(1) Å, α = β = γ = 90°) with large internal pores held open by excess solvent and unreacted ligand in the as-synthesized state. Another challenge is the synthesis process and raw …

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Simulation On Hydrogen Production From Mae-Moh Lignite Coal Gasification, Pitatchai Arunwong Jan 2025

Simulation On Hydrogen Production From Mae-Moh Lignite Coal Gasification, Pitatchai Arunwong

Chulalongkorn University Theses and Dissertations (Chula ETD)

Hydrogen energy has attracted significant attention due to its cleanliness, efficiency, and sustainability. Gasification is considered one of the most promising thermochemical routes to convert coal into high-quality syngas, which can subsequently be utilized for hydrogen production. Mae-Moh lignite, a low-rank coal with low carbon content and high moisture and volatile matter, is selected as the feedstock for this study. This research aims to develop a comprehensive simulation model of a hydrogen production process, integrating gasification, water-gas shift (WGS), acid gas removal, and hydrogen purification using the software simulator. The model predicts hydrogen product gas composition from Mae-Moh lignite under …

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Development Of Microfluidic Device To Monitor The Contamination In Drinking Water Using Impedance Spectroscopy, Pornpipat Oupchan Jan 2025

Development Of Microfluidic Device To Monitor The Contamination In Drinking Water Using Impedance Spectroscopy, Pornpipat Oupchan

Chulalongkorn University Theses and Dissertations (Chula ETD)

Microplastic contamination is a growing concern, as microplastics have been found in brain tissue and can enter the body through consumption. The objective of this research is to develop a microfluidic device to monitor microplastic particles by using electrical impedance spectroscopy principles. The device operates based on a flow-through principle. The configuration of electrode consists of copper-based cylindrical electrode with diameter of 300 micrometer and a center-to-center spacing of 2000 micrometer. The electrodes are designed to be replaceable. The microchannel has a rectangular cross-section with a width of 2000 micrometer and a height of 1000 micrometer. The microfluidic device was …

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Suppressing Bromine Volatilization In Anthraquinone–Bromine Flow Batteries Using A Low-Cost Quaternary-Ammonium Complexing Agent, Prapassorn Areebumrungsuk Jan 2025

Suppressing Bromine Volatilization In Anthraquinone–Bromine Flow Batteries Using A Low-Cost Quaternary-Ammonium Complexing Agent, Prapassorn Areebumrungsuk

Chulalongkorn University Theses and Dissertations (Chula ETD)

The deployment of anthraquinone-bromine redox flow batteries (AQBFBs) is hindered by the volatilization and corrosiveness of bromine (Br2), which elevates safety risks, causes active species loss, and reduces Coulombic Efficiency (CE). This study investigates the use of the low-cost additive 3-chloro-2-hydroxypropyltrimethylammonium chloride (CHA) as a bromine-complexing agent to mitigate these issues. The CHA additive utilizes a quaternary ammonium group to electrostatically associate with bromine and polybromide species, forming stable CHA-Brn complexes. Simultaneously, its hydroxyl functionality enhances solubility in the aqueous electrolyte, which promoted the self-recovery of this oil phase to the aqueous phase and, in turn, suppresses bromine vapor pressure …

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Development Of P-Type Cesium Iodide Thin Film For Radiation Detection By Rf-Magnetron Sputtering, Rhett Simon Tabbada Jan 2025

Development Of P-Type Cesium Iodide Thin Film For Radiation Detection By Rf-Magnetron Sputtering, Rhett Simon Tabbada

Chulalongkorn University Theses and Dissertations (Chula ETD)

Cesium iodide (CsI) is a wide-bandgap alkali halide semiconductor with strong potential for radiation detection and optoelectronic integration, though its intrinsic insulating nature limits charge transport. In this study, the effects of silicon (Si) doping on the structural, optical, electrical, and radiation-response capabilities as a semiconductor of CsI thin films were determined. The CsI thin films were deposited on n-Silicon (n-Si) (100) substrates using magnetron sputtering. In the optimization of sputtering conditions, three films with a thickness of 250 nm were fabricated with varying sputtering power for Si: 0W, 5W, and 10W, while keeping the sputtering power for CsI constant …

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Properties Modification Of High-Density Polyethylene Blending With Polypropylene Carbonate-Grafted-Stearic Acid, Suphiriya Khongphom Jan 2025

Properties Modification Of High-Density Polyethylene Blending With Polypropylene Carbonate-Grafted-Stearic Acid, Suphiriya Khongphom

Chulalongkorn University Theses and Dissertations (Chula ETD)

The purpose of this study is to improve the mechanical properties of high-density polyethylene (HDPE) by incorporating it with polypropylene carbonate-grafted-stearic acid (PPC-g-ST). PPC was modified with stearic acid to enhance interfacial adhesion and compatibility between HDPE and PPC. The blends were prepared using an internal mixer at 160°C with a rotation speed of 60 rpm for 8 minutes. PPC-g-ST was added to PPC at 3, 5, 7, and 10 wt% contents. FTIR confirmed the formation of ester linkages between the carboxylic groups of stearic acid (ST) and the hydroxyl groups of PPC through the appearance of characteristic absorption bands. …

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Endoplanar: Deformable Planar-Based Gaussian Splatting For Surgical Scene Reconstruction, Thatphum Paonim Jan 2025

Endoplanar: Deformable Planar-Based Gaussian Splatting For Surgical Scene Reconstruction, Thatphum Paonim

Chulalongkorn University Theses and Dissertations (Chula ETD)

Precise modeling of deformable anatomical structures from stereoscopic endoscopic footage plays a critical role in advancing surgical guidance and robotic automation within image-assisted medical procedures. Recent advances in Gaussian splatting have demonstrated real-time visualization capabilities with notable quality on endoscopic data; however, traditional 3D Gaussian representations introduce volumetric artifacts that compromise geometric fidelity and depth accuracy. We address these challenges through EndoPlanar, a deformable planar Gaussian framework that projects volumetric primitives onto planar surfaces. This planar formulation facilitates bias-free depth calculation and normal vector derivation—capabilities that remain elusive with standard ellipsoidal representations. We further incorporate a regularization mechanism to ensure …

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Advancing Voice Spoofing Detection In Thai : A Comprehensive Dataset And Performance Analysis On Speaking Styles And Channel Effects, Ticho Urai Jan 2025

Advancing Voice Spoofing Detection In Thai : A Comprehensive Dataset And Performance Analysis On Speaking Styles And Channel Effects, Ticho Urai

Chulalongkorn University Theses and Dissertations (Chula ETD)

Voice authentication is increasingly used in applications such as banking and call center verification, but it faces serious risks from spoofed voices. Recent advances in text-to-speech (TTS) and voice cloning make it possible to generate highly natural fake speech, creating an urgent need for robust anti-spoofing systems. While most prior work focuses on English, little research addresses the Thai language. To fill this gap, we present the Chula Spoofed Speech (CSS) dataset, a large-scale Thai corpus containing 1.3M utterances of both bona fide and synthetic speech. The synthetic samples are generated using five state-of-the-art TTS systems from the same utterances …

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Bismuth Surfactant-Mediated Epitaxy Of Gaas(Bi) On On-Axis Ge(100) Substrates, Valgeir Sigmarsson Jan 2025

Bismuth Surfactant-Mediated Epitaxy Of Gaas(Bi) On On-Axis Ge(100) Substrates, Valgeir Sigmarsson

Chulalongkorn University Theses and Dissertations (Chula ETD)

In this work, Bi-surfactant-mediated epitaxy is applied in GaAs(Bi) film deposition on nom- inally on-axis Ge(100) substrates to investigate its effect on mitigating the formation of anti-phase domains (APDs) inherent to the polar-on-non-polar GaAs/Ge(100) heterostructure. GaAs(Bi) layers were deposited by solid-source molecular beam epitaxy (MBE) with a V/III ratio of ~90 and stepwise variations in Bi flux between samples. The Bi-free GaAs sample exhibited an unstable RHEED pattern indicating ill-ordered growth mode, confirmed by AFM showing an amor- phous surface with an RMS value of ~20 nm. In contrast, Bi-assisted growth produced stable RHEED (1×3) surface reconstructions. AFM revealed single-crystal …

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Risk Management For Irrigation Water Pumping Project In Myin Gyan District, Myanmar, Ye Lin Aung Jan 2025

Risk Management For Irrigation Water Pumping Project In Myin Gyan District, Myanmar, Ye Lin Aung

Chulalongkorn University Theses and Dissertations (Chula ETD)

This study evaluates risk and performance management in the Si Mee Khon irrigation water pumping project in Myin Gyan District, Myanmar. Although intended to supply irrigation to 5,000 acres of farmland, the project has fallen short of planned targets. By Q3 2025, 53.62% of the budget had been spent while only 44% of the intended coverage had been completed, signalling significant delays and cost inefficiencies. The research identifies and prioritises key risks, assesses their effects on schedule and cost performance, and proposes mitigation strategies. A mixed-method approach was used, combining interviews with twenty MOALI officials and quantitative analysis based on …

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Evaluation Of Heavy Metal Bioaccumulation And Growth In Hemp From Chicken Manure, Vermicompost, And Wastewater Sludge With Biochar And Health Risk Assessment, Chutiphan Sangsoda Jan 2025

Evaluation Of Heavy Metal Bioaccumulation And Growth In Hemp From Chicken Manure, Vermicompost, And Wastewater Sludge With Biochar And Health Risk Assessment, Chutiphan Sangsoda

Chulalongkorn University Theses and Dissertations (Chula ETD)

Hemp (Cannabis sativa L.) has become an economically valuable crop with a wide range of benefits. To promote more sustainable agricultural systems, the use of recycled substrates has increasingly replaced traditional fertilizers. However, substrates such as dry chicken manure, vermicompost, and wastewater sludge (WWS) combined with biochar often contain heavy metal contaminants, which may pose health risks through exposure to hemp. This study investigated three cultivars Rosella, Superwoman S1, and Red Robin over a 120-day period. The objectives were: (1) to compare the effects of dry chicken manure, vermicompost, and wastewater sludge (with and without biochar) on soil nutrient quality …

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Interaction Between Extreme Temperature Events And Air Pollution On Mortality In Thailand : A Nationwide Time Series Study, Phichet Khunthong Jan 2025

Interaction Between Extreme Temperature Events And Air Pollution On Mortality In Thailand : A Nationwide Time Series Study, Phichet Khunthong

Chulalongkorn University Theses and Dissertations (Chula ETD)

Climate change has increased the frequency and intensity of extreme temperature events (ETEs; heat and cold waves), concomitantly affecting PM2.5 fluctuation. However, limited research has investigated the interaction of ETEs and PM2.5 on mortality, particularly in tropical regions where the interaction could influence differently from cold countries. A two-stage time-series using distributed lag non-linear models was employed to estimate region-specific relative risks and 95% confidence intervals (RRs and 95% CIs) of ETEs and PM2.5 on daily cardiovascular and respiratory mortality. The relative excess risk due to interaction (RERI) was examined to quantify additive effects. Cold waves had the greatest effect …

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