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2020

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Improved Adaptive Fractional Order Differential Method For Medical Image Enhancement, Wasin Tranghiranyathorn Jan 2020

Improved Adaptive Fractional Order Differential Method For Medical Image Enhancement, Wasin Tranghiranyathorn

Chulalongkorn University Theses and Dissertations (Chula ETD)

In this work, we propose a construction of a new 5x5 fractional order differential mask that uses sixteen directions of gradient operator and weights each pixel in the mask by the Euclidean distance from the center of the mask. Then, we apply this new mask to the Adaptive Fractional Differential Algorithm (AFDA). The AFDA allows the optimal fractional order of each pixel to be obtained using an adaptive function constructed based on the area feature of image. Experimental results for medical images, show that the AFDA with the new mask gives better image enhancement than the original AFDA. It makes …

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Knight's Tours On Ringboards, Deficient 4 X N Chessboards And Some L-Boards, Wasupol Srichote Jan 2020

Knight's Tours On Ringboards, Deficient 4 X N Chessboards And Some L-Boards, Wasupol Srichote

Chulalongkorn University Theses and Dissertations (Chula ETD)

A (legal) knight's move is the result of moving the knight two squares horizontally or vertically on the board and then turning and moving one square in a perpendicular direction. A closed knight's tour is a sequence of knight's moves that visits every square on a given chessboard exactly once and returns to its start square. A closed knight's tour and its variations are studied widely over the rectangular chessboard or a three-dimensional rectangular box. For m,n > 2r, an (m,n,r)-ringboard or RB(m,n,r) is defined to be an m x n chessboard, denoted by CB(m x n), with the middle part …

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Sustainability Assessment Of Power Production By Chemical Looping Combustion, Watchara Uraisakul Jan 2020

Sustainability Assessment Of Power Production By Chemical Looping Combustion, Watchara Uraisakul

Chulalongkorn University Theses and Dissertations (Chula ETD)

This study investigated the chemical looping combustion (CLC) process improvement for power production from energy management, system hydrodynamics, and sustainability perspectives. In the first part, the 3k factorial design was used for systematically investigating the operating variables that affect the thermal efficiency of the CLC combined with the humid air gas turbine (HAT) cycle. A set of operating variables, A) pressure of the air reactor, B) air compressor stages number, C) air compression methods, and D) air flow rate, were explored. The result showed that the highest thermal efficiency was at 55.87 % when operated at (A) 15 atm, (B) …

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Drought Tolerant Gene Identification By Rice Genome Comparison And Gene Characterization In Arabidopsis Plant Model, Chutarat Punchkhon Jan 2020

Drought Tolerant Gene Identification By Rice Genome Comparison And Gene Characterization In Arabidopsis Plant Model, Chutarat Punchkhon

Chulalongkorn University Theses and Dissertations (Chula ETD)

Abiotic stresses, especially drought and salt stresses can affect plant growth and productivity. 'Kao Dawk Mali 105' ('KDML105') rice is one of the crops which has to face both drought and salt stresses as it is grown in rain-fed saline soil in the northeastern region of Thailand, where the irrigation is limited. CSSL104, a chromosome substitution line with 'KDML105' genetic background, was developed in order to improve drought tolerant ability of 'KDML105' rice by transferring the drought tolerant (DT)-QTL region from double haploid line, DH103. Photosynthesis parameters of CSSL104 and its parental lines, 'KDML105' and DH103, were investigated, when they …

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Synthesis Of Sulfonamide Chalcones As Α-Glucosidase Inhibitors, I Putu Sukanadi Jan 2020

Synthesis Of Sulfonamide Chalcones As Α-Glucosidase Inhibitors, I Putu Sukanadi

Chulalongkorn University Theses and Dissertations (Chula ETD)

Diabetes mellitus occurs from deficiencies in insulin secretion or insulin resistance which leads over time to high risk for long-term macro-and microvascular complications. Diabetes mellitus type 2 contributes to more than 90% of all cases worldwide. One approach of treatment for this disorder is utilizing α-glucosidase inhibitors. Certain sulfonamides and chalcones are considered as viable candidates that are effective in reducing hyperglycemia. Forty-seven sulfonamide chalcones were synthesized by the Claisen-Schmidt reaction with various substituents on the A, B, and C-rings furnishing the desired products with 50-95 %yield. All compounds were-tested for α-glucosidase inhibitory activity. Twenty-nine compounds exhibited a very strong …

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Sexual Behaviors Of Indochinese Long-Tailed Macaque Macaca Fascicularis In Comparison With Sundaic Long-Tailed Macaque, Prangmas Kumpai Jan 2020

Sexual Behaviors Of Indochinese Long-Tailed Macaque Macaca Fascicularis In Comparison With Sundaic Long-Tailed Macaque, Prangmas Kumpai

Chulalongkorn University Theses and Dissertations (Chula ETD)

Regarding to the previous studies reported that the past hybridization event between rhesus (Macaca mulatta; Mm) and long-tailed (M. fascicularis; Mf) macaques was occurred by the southward introgression of male Mm into Mf population, thus the Mf originating from Indochinese region carried higher level of genetic admixture of Mm ancestry than the Mf living in Sundaic region. Since it was reported that Mf are non-seasonal breeder while Mm are seasonal breeder, thus, it is interesting to compare the sexual behaviors between Indochinese and Sundaic Mf. Mf populations at Wat Haad Moon Kra Beau, Pichit province (WHM; 16° 51′N) and Khao …

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Discrete-Time Risk Model Based On Zero Inflated Poisson Time Series, Siwarak Sawongnam Jan 2020

Discrete-Time Risk Model Based On Zero Inflated Poisson Time Series, Siwarak Sawongnam

Chulalongkorn University Theses and Dissertations (Chula ETD)

An important goal of actuary is to develop models for company portfolio and insurance products. Risk measurement is one of the essential measures that inform actuaries and risk managers about the degree to which the risk bearing entity. To have precise risk measure, we require an appropriate claim count process. The common claim count processes are usually constructed from the Poisson distribution. However, insurance data have generally excess zeros which causes the overdispersion. This violates the assumption of the Poisson distribution. Therefore, alternative distributions accommodating zero count are explored in literature. The zero inflated Poisson distribution is one of the …

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Electrochemical Paper-Based Immunosensor For Biomarkers Detection, Suchanat Boonkaew Jan 2020

Electrochemical Paper-Based Immunosensor For Biomarkers Detection, Suchanat Boonkaew

Chulalongkorn University Theses and Dissertations (Chula ETD)

This dissertation focused on the development of electrochemical paper-based immunosensor for determining essential biomarkers by using a label-free immunoassay. This dissertation can be divided into four main parts. In the first part, an origami paper-based analytical device (oPAD) was developed for c-reactive protein (CRP) detection. oPAD was designed to combine the preparation of immunosensor and detection step into a single device. A gold nanoparticle modified graphene screen-printed carbon electrode (AuNPs/G/SPCE) was utilized to enhance the sensitivity of the electrode. The developed sensor was successfully applied to determine CRP in a certified serum sample. For the second part, an electrochemical paper-based …

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Communication Strategy For Conservation Of Thai Food Product : A Case Study Of Moo-Naem, Ananporn Sakulraungsri Jan 2020

Communication Strategy For Conservation Of Thai Food Product : A Case Study Of Moo-Naem, Ananporn Sakulraungsri

Chulalongkorn University Theses and Dissertations (Chula ETD)

The study of Communication strategy for conservation of thai food product : a case study of Moo-Naem consisted of three objectives. 1) To add value to Moo-Naem and communicate the value to its customer; 2) To encourage people to perceive the value of Moo-Naem and purchase Moo-Naem; and 3) To use communication strategy as a tool to conserve Moo-Naem as the traditional and cultural cuisine. Two methodologies were utilized: 1) questionnaire surveys in which the population of the study is the people who lived in Bangkok, Thailand. Simple random sampling method was applied and self-administrated written in Thai and English …

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Effects Of Soil Composition, Surfactant Structure And Washing Conditions On Diesel Contaminated Soil Removal Efficiency Using Micellar Solution, Angkana Jantanaprasartporn Jan 2020

Effects Of Soil Composition, Surfactant Structure And Washing Conditions On Diesel Contaminated Soil Removal Efficiency Using Micellar Solution, Angkana Jantanaprasartporn

Chulalongkorn University Theses and Dissertations (Chula ETD)

Surfactant solutions are commonly used for the remediation of petroleum-contaminated soil due to their good petroleum removal performance, time-saving capability, and cost effectiveness. However, applying surfactants in excess concentrations could make oil recovery difficult. Moreover, residual surfactants in soil are toxic to microorganisms and plants. Thus, it is crucial to identify a suitable surfactant concentration for soil washing applications. The main objective of this study was to evaluate the effect of soil composition (sand, silt, clay and organic matter), surfactant structure (Tween 20, 40, 60 and 80, and Tergitol 15-S-7, 9 and 15). Subsequently, two surfactants from each series (Tween …

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Factors Influencing Adoption And Usage Probability Of Car Sharing In Bangkok, Baweena Ruamchart Jan 2020

Factors Influencing Adoption And Usage Probability Of Car Sharing In Bangkok, Baweena Ruamchart

Chulalongkorn University Theses and Dissertations (Chula ETD)

This thesis aimed to examine factors influencing adoption and usage probability of car sharing in Bangkok. There were two phases of study. The first phase was examining the factors influencing the probability of using of car sharing. The latter was designed to assess customers' attitudes toward the intention to use car sharing. Both studies employed a quantitative method of data collection and analysis. Study One assessed the likelihood of using car sharing from customers' characteristics in three main groups: socio-economic status, travel behavior and car-sharing preferences. The data were collected through a questionnaire with the target population group. In total, …

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Environmental Impacts And Hazardous Characteristics Of Led Lamps Waste, Delpavita Koralege Lakshani Diluka Gunawardhaa Jan 2020

Environmental Impacts And Hazardous Characteristics Of Led Lamps Waste, Delpavita Koralege Lakshani Diluka Gunawardhaa

Chulalongkorn University Theses and Dissertations (Chula ETD)

LED lighting technology has strongly taken the Thai lighting market due to the high consumption in residential, industrial and commercial sectors so the sustainability of LED lamps chain is considered as a critical factor for Thai lighting market. Additionally LED lamps waste consist of toxic metals hence improper landfilling has high potential to create negative environment and human health impact due to toxic metals contamination to environment. Therefore, this study focused on (1) quantifying environmental impact due to consumption behaviors among industrial lighting consumers and (2) hazard characterization and toxicity estimation of improper landfilling of LED lamps waste. Environmental impact …

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Pvdf Hollow Fiber Membrane Modification For Dye Wastewater Treatment By Ozonation Membrane Contacting Process, Hanh Le Thi My Jan 2020

Pvdf Hollow Fiber Membrane Modification For Dye Wastewater Treatment By Ozonation Membrane Contacting Process, Hanh Le Thi My

Chulalongkorn University Theses and Dissertations (Chula ETD)

One of the main pollutions from textile wastewater is the dyeing wastewater containing color and organic matters. Among the treatment methods of dye wastewater, ozonation membrane contactor was used as the concept of this research. PVDF membranes were developed by pulse inductively coupled plasma (PICP) and grafted by organosilanes for hydrophobicity enhancement applied for dye wastewater treatment by ozonation membrane contactor. To obtain a stable grafting, the surface of PVDF hollow fiber membrane was activated by the plasma operating condition including two different plasma gases (oxygen and argon), applied voltage and pressure, plasma treatment shot, followed by grafting with four …

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Assessing Environmental Impact Through Dpsir Framework And Environmental Justice Lenses:A Case Study Of Inland Capture Fisheries In Mahakam River, Etik Sulistiowati Ningsih Jan 2020

Assessing Environmental Impact Through Dpsir Framework And Environmental Justice Lenses:A Case Study Of Inland Capture Fisheries In Mahakam River, Etik Sulistiowati Ningsih

Chulalongkorn University Theses and Dissertations (Chula ETD)

Inland capture fisheries significantly contribute to the achievement of SDG, but most inland capture fisheries are poorly managed or not managed at all. Inland fishery is often facing against the big-scale industrial project. In the Middle Mahakam Area, two dominant natural resources exploited for the industrial project are palm oil and coal mining. Palm oil production, coal mining production, the human population was increasing in the last ten years, and on the opposite, the water quality index is decreasing. However, although many previous studies suggested that fish catches are declining, fisheries statistics show the opposite data. Government statistics show that …

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Development Of X-Ray Shielding Material From Combination Of Amorphous Cellulose Of Used Paper, Barium Sulphate, And Natural Rubber, Harinate Mungpayaban Jan 2020

Development Of X-Ray Shielding Material From Combination Of Amorphous Cellulose Of Used Paper, Barium Sulphate, And Natural Rubber, Harinate Mungpayaban

Chulalongkorn University Theses and Dissertations (Chula ETD)

This research aimed to fabricate X-ray shielding substrates using amorphous cellulose from office waste paper and eucalyptus pulp mixed with natural rubber to produce the prototypes. The amorphous cellulose was prepared using only the sulfuric acid at 0 °C to rearrange the crystalline chain to the amorphous chain. After that, the barium sulfate/amorphous cellulose composite (Ba/AC) was regenerated using barium chloride solution. The shielding sheets were formulated by mixing vulcanization natural rubber individual with Ba/AC from office waste paper (NR-W), the purified eucalyptus pulp (NR-E), and barium sulfate powder (NR-P). The NR-W and NR-E were shown the predominant attenuation than …

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Prediction Of Arsenic Contamination In Rayong Groundwater Basin Using Machine Learning Based Approaches, Narongpon Sumdang Jan 2020

Prediction Of Arsenic Contamination In Rayong Groundwater Basin Using Machine Learning Based Approaches, Narongpon Sumdang

Chulalongkorn University Theses and Dissertations (Chula ETD)

The present study used three algorithms consisting of Support Vector Machine (SVM), Random Forest (RF), and Artificial Neuron Network (ANN) to locate risk area of arsenic (As)contamination in Rayong coastal aquifers, Thailand. There were three parts in this study consisting of 1) selecting the proper parameters 2) selecting the appropriate model, and 3) constructing the risk map of As. To perform models efficiently, the parameters used to generate the models have to be selected based on the correlation of each hydrochemical parameter with As concentration, which could explain the mechanisms of As release in groundwater. Due to major parameters in …

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Factors Influencing Adoption And Usage Probability Of Automated Parcel Lockers, Orawee Thongkam Jan 2020

Factors Influencing Adoption And Usage Probability Of Automated Parcel Lockers, Orawee Thongkam

Chulalongkorn University Theses and Dissertations (Chula ETD)

The study proposes a model to predict probability to use Automated Parcel Locker (APL) in Bangkok by adopting Multiple Linear Regression. In addition, to help business to market to the right target and increase the intention to use, the study investigates factors influencing Intention to use APL by employing Structural Equation Model (SEM). The framework is developed based on Technology Acceptance Model (TAM) and other external factors. The questionaries were conducted for both methods with 718 observation and 500 responses, randomly selected. The results show that variables best predict probability to use APL is price set with discount, followed by …

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Synthesis Of Nanoscale Zerovalent Iron (Nzvi) Derived From Lignin Containing Wastewater For Arsenic Removal, Phoomipat Jungcharoen Jan 2020

Synthesis Of Nanoscale Zerovalent Iron (Nzvi) Derived From Lignin Containing Wastewater For Arsenic Removal, Phoomipat Jungcharoen

Chulalongkorn University Theses and Dissertations (Chula ETD)

Nanoscale zerovalent iron (nZVI) plays a significant role in environmental remediation including the removal of arsenic from groundwater and drinking water. This study synthesized modified nZVI particles in order to remove arsenic in drinking water. Reductive precipitation under various conditions was used to produce non-modified nZVI (B-nZVI) and lignin-modified nZVI using either 1 g/L lignin solution (L-nZVI) or pulp and paper wastewater (P-nZVI) as the substrate. Ferrous to borohydride molar ratio of 1:1 was found to be the most appropriate ratio for L-nZVI and P-nZVI production since lignin was incorporated into the nZVI structure the most. According to TEM analysis, …

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Fishermen's Participation In Marine Litter Collection Schemes In Thailand, Phornphavit Thongphaijit Jan 2020

Fishermen's Participation In Marine Litter Collection Schemes In Thailand, Phornphavit Thongphaijit

Chulalongkorn University Theses and Dissertations (Chula ETD)

Marine litter is a global environmental problem that poses various threats to the environment, the economy and society. Its impacts, for example, are the cost of beach cleaning, tourism, the beautiful landscape and etc. Marine litter, which later breaks into microplastics, affects marine lives contributing to the loss of economy to the people who depend on them. Several measures are used to tackle marine litter, including prevention and reduction of waste generation, prevention and reduction of litter reaching the marine environment, and marine litter removal. The latter is essential to clean already-at-sea litter or marine debris. Thailand, among the top …

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Perspectives And Challenges Of Green Hotel In Thailand, Pornwajee Sangmanee Jan 2020

Perspectives And Challenges Of Green Hotel In Thailand, Pornwajee Sangmanee

Chulalongkorn University Theses and Dissertations (Chula ETD)

The hotel business is intense resource consumption such as water, energy, and non-durable products to delight customers, leading to environmental problems. With this regard, the transformation of the green hotel and environmental saving programs can dwindle the hotel property's adverse impacts. The purposes of this paper are 1) to study the perception of hotel practitioners and stakeholders toward the critical challenges of green hotel transformation and 2) to propose the recommendations for green hotel operations and certification scheme in Thailand. The study employed mixed methods to collect the data. The in-depth interviews were along with field observation; the interviews data …

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City-Wide Greenhouse Gas Mitigation Options To Support Global Climate Goals: Case Studies Of Bangkok, Chiang Mai, And Rayong, Thailand, Sittisak Sugsaisakon Jan 2020

City-Wide Greenhouse Gas Mitigation Options To Support Global Climate Goals: Case Studies Of Bangkok, Chiang Mai, And Rayong, Thailand, Sittisak Sugsaisakon

Chulalongkorn University Theses and Dissertations (Chula ETD)

The action of city on climate mitigation becomes a crucial role. The aims of this study were to quantify greenhouse gases (GHGs) emission, identify feasibility of mitigation options in selected provinces, and to evaluate the performance of local capacity to support Thailand's Nationally Determined Contributed (NDC) and 1.5oC limit pathway. Three provinces, including Bangkok, Chiang Mai and Rayong of Thailand were selected as case studies. The results revealed that stationary energy was the greatest contribution to the city's GHGs emissions in all case studies. Transportation was the second largest emitter in Bangkok and Chiang Mai, whereas IPPU was the second …

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Leaching Potential Assessment Of Atrazine And Nitrate In Sugarcane Field, Suphan Buri Province, Sorranat Ratchawang Jan 2020

Leaching Potential Assessment Of Atrazine And Nitrate In Sugarcane Field, Suphan Buri Province, Sorranat Ratchawang

Chulalongkorn University Theses and Dissertations (Chula ETD)

Atrazine is widely used as a herbicide to control annual broadleaf in agricultural area such as rice and sugarcane. It is considered as one of endocrine disrupting chemicals. Atrazine also affects liver, the central nervous system, immune system and cardiovascular function. The study area is sugarcane field in U-thong and Song Phi Nong district, Suphan Buri province. In this area, soil and groundwater samples were collected at eight different points distributed over the sugarcane area with different soil types. Batch adsorption experiment was carried out to evaluate the proper adsorption isotherm of each soil. Additionally, groundwater samples were analyzed for …

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Development Of Tod Readiness Index And Its Application To Transit Station In Bangkok, Srisamrit Supaprasert Jan 2020

Development Of Tod Readiness Index And Its Application To Transit Station In Bangkok, Srisamrit Supaprasert

Chulalongkorn University Theses and Dissertations (Chula ETD)

Studies on the Transit-Oriented Development (TOD) for Bangkok are found sparingly. The TOD concept is a supportive development for the rapidly changing city in order to reduce urban transport problems while encouraging people to shift transport modes to use public transportation instead of private cars. This study discusses the context of TOD in the density, the design, and the diversity of land use around transit stations among successful stations in many countries. There were 18 station areas in Bangkok which, by using the TOD Readiness score, the assessment of the stations implies that the higher scoring transit stations are more …

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Detection Of Arsenite-Oxidizing Bacteria In Groundwater From A Gold Mine Under Different Geochemical Environments, Supeerapat Kraidech Jan 2020

Detection Of Arsenite-Oxidizing Bacteria In Groundwater From A Gold Mine Under Different Geochemical Environments, Supeerapat Kraidech

Chulalongkorn University Theses and Dissertations (Chula ETD)

Millions of people around the world potentially expose to arsenic (As) contaminated groundwater. Besides, the dominant form of As in groundwater is arsenite (As+3) and is more toxic than arsenate (As+5). This study integrated the microbial investigation, geochemical modeling, and multivariate statistical analysis to investigate the arsenite-oxidizing bacteria community from As-contaminated groundwater and its environmental influencing factors in order to understand and further develop the in-situ arsenic bioremediation technology. Microbial investigation was focusing on the detection and identification of native arsenite-oxidizing bacterial community using PCR-DGGE, cloning and sequencing of arsenite oxidase (aoxB) gene amplicons. Nine groundwater samples were collected from …

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Sustainable Business Development Through Sufficiency Economy Practice : A Case Study Of Thai Listed Companies, Veerawin Korphaibool Jan 2020

Sustainable Business Development Through Sufficiency Economy Practice : A Case Study Of Thai Listed Companies, Veerawin Korphaibool

Chulalongkorn University Theses and Dissertations (Chula ETD)

The purpose of the research is to determine the sufficiency economy philosophy (SEP) performance through annual and sustainable development reports and simplify the outcomes by representing through a scoring system. Each of the SEP elements was aligned with each GRI sub-topic to generate a SEP scoring system. Then, the results from the scoring system were verified by testing the relationship between SEP performance and firm-specific risk of 34 Thai listed companies from 2013 to 2018 via panel data analysis. The global reporting initiative (GRI) standards were used as the fundamental scoring system as it's widely used and accepted in academic …

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Assessments Of Hydraulic Responses To Climate Variability Of Dominant Trees In Successional Forests In Khao Yai National Park For Environmental Management, Weerapong Unawong Jan 2020

Assessments Of Hydraulic Responses To Climate Variability Of Dominant Trees In Successional Forests In Khao Yai National Park For Environmental Management, Weerapong Unawong

Chulalongkorn University Theses and Dissertations (Chula ETD)

In Southeast Asia, tropical forests have been increasingly threatened by human disturbances and climate change-induced water stress. However, uncertainty remains as to how these forests would respond to environmental changes under water deficit conditions. Here, we conducted a study of seasonal variation in leaf water status and hydraulic properties of dominant tree species across forest successional stages in Khao Yai National Park, Thailand. Specifically, we measured midday leaf water potential (Ψmd) during the wet and dry season, and assessed branch xylem vulnerability at which 50% is lost (P50). The associations between P50 and maximum xylem hydraulic conductivity (Ksmax) and maximum …

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Learning-Based Approach For Visual Quality Enhancement On High Efficiency Video Coding Standard, Sovann Chen Jan 2020

Learning-Based Approach For Visual Quality Enhancement On High Efficiency Video Coding Standard, Sovann Chen

Chulalongkorn University Theses and Dissertations (Chula ETD)

High Efficiency Video Coding (HEVC) has dramatically enhanced the coding efficiency compared to the previous video coding standard, H.264/AVC. However, the existing rate control updates its parameters according to a fixed initialization, which can cause error prediction of bit allocation to each coding tree unit (CTU) in frames. In this work, a learning-based mapping between rate control parameters and video contents is proposed to achieve an accurate target bit rate and good video quality. The proposed framework contains two main structural codings, including spatial and temporal coding. We initiate an effective learning-based particle swarm optimization for both spatial and temporal …

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The Deactivation Study Of Titanium Dioxide Catalyst In Thermochemical Processes Via Density Functional Theory, Chinanang Ngamlaor Jan 2020

The Deactivation Study Of Titanium Dioxide Catalyst In Thermochemical Processes Via Density Functional Theory, Chinanang Ngamlaor

Chulalongkorn University Theses and Dissertations (Chula ETD)

In this study, the investigation of catalytic deactivation of TiO2 by coking was performed using DFT. The effect of the Hubbard U, which was varied as U equal 4 to 6 eV and Van der Waal corrections on electronic properties were also investigated. The effect of temperature in the range of 400-1000°C was also studied. This work aims to understand relatives of coke formation, oxygen vacancy, phase transformation. The increment of the Hubbard U values provide a more accurate quantitative cited by the energy gap from the experimental investigation, the appropriate U value of the A-TiO2 (101) is 4 eV, …

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Synthesis And Anti-Psoriatic Activity Of A Mycophenolic Acid-Curcumin Conjugate As A Mutual Prodrug, Yonelian Yuyun Jan 2020

Synthesis And Anti-Psoriatic Activity Of A Mycophenolic Acid-Curcumin Conjugate As A Mutual Prodrug, Yonelian Yuyun

Chulalongkorn University Theses and Dissertations (Chula ETD)

Due to its several mechanisms of action, curcumin (CUR) has been employed as adjuvant therapy in treating psoriasis. Limited oral bioavailability was the problem for the development of CUR for therapeutic purposes. Therefore, many approaches, including the prodrug strategy, have been devised to address Cur's drawbacks. CUR was conjugated with mycophenolic acid (MPA) as a new prodrug in this research. Characterization of MPA-CUR structure was done by FT-IR, 1H-NMR, 13C-NMR, and MS. MPA-CUR showed water solubility at 0.73 μM and log P at 2.33, respectively. MPA-CUR was found more stable in buffer solutions than CUR and MPA. In vitro anti-psoriatic …

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Surface-Enhanced Raman Scattering Using Fluorescence-Quenched Carbon Quantum Dots For Mercury Ion Detection, Andaru Dena Prasiwi Jan 2020

Surface-Enhanced Raman Scattering Using Fluorescence-Quenched Carbon Quantum Dots For Mercury Ion Detection, Andaru Dena Prasiwi

Chulalongkorn University Theses and Dissertations (Chula ETD)

Mercury ion (Hg2+) is one of the most challenging problems due to its high toxicity at low concentration and bioaccumulative effects affecting human health. Herein, we propose a strategy to exploit the fluorescence quenching of carbon quantum dots (CQDs) combined with surface-enhanced Raman scattering (SERS) technique to detect Hg2+. CQDs exhibit strong fluorescence emission interfering SERS measurement. However, with the presence of Hg2+, fluorescence from CQDs can be quenched, and the SERS spectrum can be collected. In this work, SERS spectra of rhodamine 6G (R6G) incorporated with CQDs and Hg2+ (0.100‒100 ng/L) were studied. The SERS spectra of R6G was …

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