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Gamma-Aminobutyric Acid Contents And Glutamate Decarboxylase Activity In Local Thai Rice And Transgenic Rice Overexpressing Oscam1-1 Gene, Potitorn Kanchitanurak Jan 2022

Gamma-Aminobutyric Acid Contents And Glutamate Decarboxylase Activity In Local Thai Rice And Transgenic Rice Overexpressing Oscam1-1 Gene, Potitorn Kanchitanurak

Chulalongkorn University Theses and Dissertations (Chula ETD)

In rice grain, many considerable nutrients are shown to have potential functional food benefits. GABA is a metabolic product that is primarily produced by the decarboxylation of L-glutamic acid (L-Glu), catalyzed by glutamate decarboxylase (GAD), which is a cytosolic enzyme regulated by Ca2+-calmodulin (CaM) complex. The accumulation of GABA is related to the activity of GAD and substrate concentration of L-Glu. In this study, analysis of GABA contents in local Thai rice (Oryza sativa L.) during 0-72 h of germination revealed that GABA concentrations rapidly increased and the pattern of increment varied among different rice varieties. Genome-wide association mapping using …

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A Comparative Study Of Consumer Protection Regulation In The Case Of Online Influencers' Hidden Advertisement: Towards The Development Of A Universal Regulatory Framework, Shuang Liang Jan 2022

A Comparative Study Of Consumer Protection Regulation In The Case Of Online Influencers' Hidden Advertisement: Towards The Development Of A Universal Regulatory Framework, Shuang Liang

Chulalongkorn University Theses and Dissertations (Chula ETD)

Social media has become highly influential, with statistics showing that TikTok, one of the leading social media platforms, has over 600 million active users. The popularity of these platforms has led to a rise of "influencers" who are individuals with a strong targeted audience of followers, carefully built through their online activities such as posting photographs and short videos on the platforms. As their posts attract significant attention from their followers, the influencers may, in return for commercial products being featured on their posts, receive benefits which mainly include direct financial benefits, and indirect financial benefits such as free products. …

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Toward Transparency : A Study On The Governance Of Investment Infrastructure Funds In Transportation Projects In Indonesia, Tanty Larasati Jan 2022

Toward Transparency : A Study On The Governance Of Investment Infrastructure Funds In Transportation Projects In Indonesia, Tanty Larasati

Chulalongkorn University Theses and Dissertations (Chula ETD)

This research examines information transparency on the governance of infrastructure investment funds in Indonesia, including the contrast with the concepts of collective investment schemes, European Long-Term Investment Fund, and infrastructure funds in Thailand. The hypothesis of this study is that the regulatory framework of infrastructure investment funds in Indonesia is less comprehensive in enabling the availability and clarity of information for investors’ informed decisions, compared to such concepts. Correspondingly, it finds that information asymmetry occurred due to minimal access and amount of information for assessment. The parties interested in this transaction tend to withhold their key concerns or disseminate them …

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Existence And Enforcement Of A Right To Be Forgotten In China, Yue Zhen Jan 2022

Existence And Enforcement Of A Right To Be Forgotten In China, Yue Zhen

Chulalongkorn University Theses and Dissertations (Chula ETD)

This research examines establishment and enforcement of the right to be forgotten under the Chinese legal system, including the origin and characteristics of the "right to be forgotten", as well as the regulations on "erasure" in China. It finds that protection challenges stem from the fact that personal data can be publicly accessible online. In addition, different countries, which are electronically connected through the internet, may have different legal protection measures for a right to be forgotten. In China, a legislative protection on a right to be forgotten is relatively weak. Firstly, compared with the General Data Protection Regulation (GDPR), …

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Simulation Of Photoelectrochemical Co2 Conversion To Useful Chemicals, Aroonroj Chaosukho Jan 2022

Simulation Of Photoelectrochemical Co2 Conversion To Useful Chemicals, Aroonroj Chaosukho

Chulalongkorn University Theses and Dissertations (Chula ETD)

Photoelectrochemical (PEC) CO2 reduction reaction (CO2 RR) is one of the possible solutions to reduce CO2 emissions. Among a variety of products derived from CO2 RR, CO, and HCOO- are found to be interesting chemicals. The geometry and arrangement of the main components of PEC cells play important roles in the cell performance of CO2 RR. In this study, a correlation of hydrodynamics and kinetics on the TiO2-photoanode and SnO2-GDE, used as a cathode, was investigated by COMSOL Multiphysics by controlling operating conditions for 2-dimensional different PEC cell configurations. The Microfluidic flow cell (MFC) with a zero-gap anode with a …

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Techno-Economic Analysis Of Succinic Acid Production From Sugarcane Molasses, Apitsada Rongsawad Jan 2022

Techno-Economic Analysis Of Succinic Acid Production From Sugarcane Molasses, Apitsada Rongsawad

Chulalongkorn University Theses and Dissertations (Chula ETD)

This study proposes an alternative approach to address global warming concerns by introducing bio-based succinic acid production derived from molasses and waste CO2 in ethanol production as a substitute for conventional petroleum-based methods. The evaluation focuses on the downstream process; reactive extraction, aiming to assess its feasibility in terms of technical, economic, energy, and CO2 emission performance. The results indicate that the integrated process, Int. ETOH+SA 25:75, exhibits remarkable benefits, including a 66% reduction in CO2 emissions from ethanol production, a 77% decrease in energy consumption compared to petroleum-based methods, and NPV of 2,180 million USD with a 40.81% IRR …

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Techno-Economic And Environmental Assessment For Enhancementbiodiesel Production Process Using Rotating Tube Reactor And Dry Washing, Arthit Jarungwongsathien Jan 2022

Techno-Economic And Environmental Assessment For Enhancementbiodiesel Production Process Using Rotating Tube Reactor And Dry Washing, Arthit Jarungwongsathien

Chulalongkorn University Theses and Dissertations (Chula ETD)

The study aims at exploring the potential use of rotating tube reactor (RTR) and performing economic analysis as wells as addressing the challenges associated with the utilization of different feedstocks including of refined palm oil (RPO) and waste cooking oil (WCO) for biodiesel production. The type of feedstock strongly influenced the optimum reaction temperature. For instance, RPO can produce biodiesel in the RTR at room temperature while WCO required the external heat source for biodiesel production at 65°C. In addition, two transesterification steps of WCO were required to achieve 95.16%. Simulation results found that the process intensification using RTR and …

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Enzymatic Pretreatment Of Rice Bran Acid Oil Before Γ-Oryzanol Recovery, Asdarina Binti Yahya Jan 2022

Enzymatic Pretreatment Of Rice Bran Acid Oil Before Γ-Oryzanol Recovery, Asdarina Binti Yahya

Chulalongkorn University Theses and Dissertations (Chula ETD)

This study aims to apply enzymatic reactions for pretreating the major byproduct of rice bran oil (RBO) industry, rice bran acid oil (RBAO) before γ-oryzanol recovery. RBAO contains free fatty acids (FFAs), glycerides, and is rich in the super-antioxidant, γ-oryzanol. As a primary step to recover γ-oryzanol from RBAO, glycerides must be removed because of having similar polarity with γ-oryzanol. This study is conducted in two parts, hydrolysis and esterification/transesterification. In the first part, enzymatic hydrolysis. The study evaluates the performance of operating conditions using one factor at a time (OFAT) on the reaction time, temperature, lipase loading, water:RBAO ratio, …

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Development Of Bioplastic Composite Films With Improved Antimicrobial Properties: A Comparative Study Between Blown Film Extrusion, Doctor Blading And Spray Coating, Atiwit Singhapan Jan 2022

Development Of Bioplastic Composite Films With Improved Antimicrobial Properties: A Comparative Study Between Blown Film Extrusion, Doctor Blading And Spray Coating, Atiwit Singhapan

Chulalongkorn University Theses and Dissertations (Chula ETD)

Poly(3-hydroxybutyrate-co-4-hydroxybutyrate) (P3HB4HB) is a bioplastic that has gained attention as a potential alternative to petroleum-based plastics in film packaging due to its good barrier properties and thermal stability. However, poly(3-hydroxybutyrate-co-4-hydroxybutyrate) has no outstanding properties. Therefore, the researcher added lignin powder to improve its antimicrobial properties, another essential property of the packaging film. This work successfully prepared a composite bioplastic film between poly(3-hydroxybutyrate-co-4-hydroxybutyrate) and lignin powder by forming through a blown film extrusion, doctor blading, and spray coating. In order to give the film a high surface energy and enable it to adhere to the lignin solution on the surface, the …

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Glycerol Carbonate Production From Glycerol And Diethyl Carbonate: A Comparative Study Between A Separated Reaction/Distillation (Srd) Process And A Reactive Distillation (Rd) Process, Chayanin Sriharuethai Jan 2022

Glycerol Carbonate Production From Glycerol And Diethyl Carbonate: A Comparative Study Between A Separated Reaction/Distillation (Srd) Process And A Reactive Distillation (Rd) Process, Chayanin Sriharuethai

Chulalongkorn University Theses and Dissertations (Chula ETD)

Glycerol carbonate is one of the valuable products that can be converted from glycerol produced in the biodiesel industry. In this work, the continuous process of glycerol carbonate production via transesterification from crude glycerol and diethyl carbonate will be developed using Aspen Plus simulation. There are two processes to be considered. First, the separated reaction/distillation (SRD) process consists of a continuously stirred tank reactor for the reaction section and a distillation column for the purification section. Second, the reactive distillation (RD) process consists of a reactive distillation column that can accommodate both the reaction and purification in a single column, …

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Parameters Optimization In Chlor-Alkali Ion-Exchange Membrane Electrolysis Process With Artificial Neural Network, Kittapas Sukantowong Jan 2022

Parameters Optimization In Chlor-Alkali Ion-Exchange Membrane Electrolysis Process With Artificial Neural Network, Kittapas Sukantowong

Chulalongkorn University Theses and Dissertations (Chula ETD)

Since ion-exchange membrane electrolysis cell has developed for producing Chlor-Alkali products. New higher efficiency and lower consumption technology are released from licensors yearly, which made the process correlation deviate from the original design. The machine learning is used with “Neural Network Fitting Tool (nftool)” in MATLAB. To find a correlation between 5 inputs consisting of current density (CD, KA/m2), operation day (DOL, day), feed brine flow rate (QFB, m3/h), feed caustic flow rate (QHD, m3/h), cell temperature (T, degC) and one output which is cell voltage (CV, V). Datasets were collected from the plant information management system “exaquantum” historian database. …

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Economic Evaluation Of Ethyl Lactate Production Via Reactive Distillation At Different Concentrations Of Lactic Acid, Nattapat Klin-U-Bol Jan 2022

Economic Evaluation Of Ethyl Lactate Production Via Reactive Distillation At Different Concentrations Of Lactic Acid, Nattapat Klin-U-Bol

Chulalongkorn University Theses and Dissertations (Chula ETD)

Ethyl lactate is a green solvent made from agricultural crops, making it more environmentally friendly than petrochemical solvents. The product is obtained via esterification of lactic acid with ethanol over Amberlyst-15 acid catalyst in a reactive distillation column. In commercial-scale production of ethyl lactate, this work designs production processes at two concentrations of lactic acid (50 and 85 wt.%) and two ethanol feed temperatures (25 and 85 °C). Highly concentrated lactic acid can result in adverse effects, such as increased oligomers and reduced desired products, making a comprehensive simulation of the production process necessary to evaluate energy consumption, economics, and …

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Simultaneous Reaction And Separation Technologies For Biodiesel Production Derived From Alternative Feedstocks, Nattawat Petchsoongsakul Jan 2022

Simultaneous Reaction And Separation Technologies For Biodiesel Production Derived From Alternative Feedstocks, Nattawat Petchsoongsakul

Chulalongkorn University Theses and Dissertations (Chula ETD)

This research focused on the production of biodiesel using hybridized reactive distillation (hybridized RD) and centrifugal contractor reactor (CCR) from waste cooking oil (WCO) to reduce the operating cost. However, WCO contains some water which can cause saponification. The study showed that using two heat exchangers with hybridized RD is a simple method for water removal but it required the highest energy and cost (1.63 $/kg biodiesel). The extended spacing stage for water removal required a new hybridized RD construction with additional spacing stages. This method can handle and require less energy, resulting in lower cost (1.07 $/kg biodiesel). The …

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Sulfur-Tolerant Cobalt-Doped La0.3sr0.7tio3-D-Perovskite Cathode For Intermediate-Temperature Solid Oxide Electrolysis Cell, Natthamon Nuengjumnong Jan 2022

Sulfur-Tolerant Cobalt-Doped La0.3sr0.7tio3-D-Perovskite Cathode For Intermediate-Temperature Solid Oxide Electrolysis Cell, Natthamon Nuengjumnong

Chulalongkorn University Theses and Dissertations (Chula ETD)

Lanthanum doped strontium titanate (LST) is a perovskite cathode in Solid Oxide Electrolysis Cell (SOEC) which shows great performance in syngas production from CO2 and steam feed. However, the LST type cathode suffers from structural stability. Sulfur containing in industrial exhaust gas can affect its durability which inhibit the technology in real application. Therefore, to improve sulfur tolerance, La0.3Sr0.7Ti1-yCoyO3-δ (LSTC) by adding Co2+ metal ion at B-site when y is 0 to 20%mol was synthesized. Citrate acid-nitrate combustion method was used and the synthesized powder. LST and La0.3Sr0.7Ti0.9Co0.10O3-δ (LSTC0.10) exhibited single phase perovskite while La2O3 and La(OH)3 were observed in …

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Ethylene Polymerization With Zirconocene Catalyston Zeolite A Support Derived From Fly Ash, Natthapat Warintha Jan 2022

Ethylene Polymerization With Zirconocene Catalyston Zeolite A Support Derived From Fly Ash, Natthapat Warintha

Chulalongkorn University Theses and Dissertations (Chula ETD)

Zeolite A (LTA) synthesis from fly ash has many applications, in which metallocene catalytic support is uncommon. This research study has three parts. Firstly, investigation of the effects of immobilized MAO cocatalyst and zirconocene catalyst techniques on silica support. Immobilized MAO, followed by metallocene catalyst method had the highest catalytic activity, which was used in the next parts. The second part examined the optimal temperature and [Al]MAO/[Zr]cat ratio with ethylene polymerization in a semi-batch autoclave reactor utilizing LTA-supported metallocene catalysts. The optimal conditions were found at 80°C and [Al]MAO/[Zr]cat ratios equal to 2000 that were used in the next section. …

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Characteristics And Catalytic Properties Of Copper On Mcf-Si And Sba-15 For Hydrogenation Of Carbon Dioxide, Sirimas Suelueam Jan 2022

Characteristics And Catalytic Properties Of Copper On Mcf-Si And Sba-15 For Hydrogenation Of Carbon Dioxide, Sirimas Suelueam

Chulalongkorn University Theses and Dissertations (Chula ETD)

At present, the production of methanol from the hydrogenation of carbon dioxide is widespread. The current popular catalysts include copper oxide, zinc oxide and aluminum oxide (CZA) catalysts. As the reaction progresses, the catalyst forms coke. This causes the efficiency of the catalyst to decrease. In this study, the copper catalyst on the mesoporus silica support was investigated. This type of support has high thermal stability. Cu catalysts were synthesized on MCF-Si and SBA-15 supports with different pore morphology such as spherical and hexagonal shape, respectively, by wetness impregnation (W) method and incipient wetness impregnation (IW) with a copper loading …

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Comparison Of Techno-Economic Analysis Of 1,3-Propanediol Production From Crude Glycerol Via Chemical And Biological Methods, Sivatchaya Boriboon Jan 2022

Comparison Of Techno-Economic Analysis Of 1,3-Propanediol Production From Crude Glycerol Via Chemical And Biological Methods, Sivatchaya Boriboon

Chulalongkorn University Theses and Dissertations (Chula ETD)

At present, the biodiesel industry is expanding rapidly which could lead to an oversupply of the by-product, crude glycerol. To manage this, crude glycerol should be converted into value-added chemicals such as 1,3-propanediol (1,3-PDO). In this study, the production of 1,3-PDO via catalytic reaction is simulated using a process simulator to evaluate its techno-economic performance as well as its environmental impact. The obtained results will be compared with the conventional production of 1,3-PDO to point out the advantages that the catalytic reaction can offer in terms of economic, energy utilization, raw material utilization, and environmental impacts.

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Scale Up Of Benzoxazinone Derivative Synthesis In Batch Reactor, Sumate Boonkird Jan 2022

Scale Up Of Benzoxazinone Derivative Synthesis In Batch Reactor, Sumate Boonkird

Chulalongkorn University Theses and Dissertations (Chula ETD)

Benzoxazinone derivative is one of starting materials in the synthesis of Deferasirox (a Chelating iron for thalassemia patient). The parameters of Benzoxazinone derivative synthesis were investigated from the condensation of salicylic acid, salicylamide, cyanuric chloride, and triethylamine using toluene as solvent. The mole equivalent ratio of salicylic acid: salicylamide:cyanuric chloride:triethylamine at 1:1:0.67:1 provided the 46.77% yield of Benzoxazinone derivative in laboratory scale. Surprisingly, 4-chloro-2-(2-hydroxyphenyl)-4H-benzo[e][1,3]oxazine-4-ol was observed in the synthesis of Benzoxazinone derivative. In addition, the reaction scheme of Benzoxazinone derivative synthesis was proposed as a model for the study of the chemical kinetic constant. Furthermore, the scale up of Benzoxaxinone …

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Effects Of Zinc Oxide On Thermal, Mechanical, Morphological, And Gas Barrier Properties Of Polybutylene Succinate/ Poly(3-Hydroxybutyrate-Co-4-Hydroxybutyrate) Films, Sunisa Suwatthi Jan 2022

Effects Of Zinc Oxide On Thermal, Mechanical, Morphological, And Gas Barrier Properties Of Polybutylene Succinate/ Poly(3-Hydroxybutyrate-Co-4-Hydroxybutyrate) Films, Sunisa Suwatthi

Chulalongkorn University Theses and Dissertations (Chula ETD)

Currently, conventional polymers from petrochemical processes have low biodegradability and remain in the environment for several hundred years. This has negative effects on the environment. This research aims to improve the properties of biopolymers such as poly(butylene succinate) (PBS) and poly(3-hydroxybutyrate-co-4-hydroxybutyrate) (P3HB4HB). P3HB4HB was selected to blend with PBS in with weight ratios of PBS:P3HB4HB was 90/10 and ZnO nanoparticles (0.5, 1 and 2%) was selected as a nucleating agent. The melt blending process using an internal mixer and molded into a film using a compression molding process. The chemical structures, morphological properties, thermal properties, dynamic mechanical properties, mechanical properties …

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Control Of A Polybutylene Succinate (Pbs) Polymerization In A Semi-Batch Reactor By Neural Network Model Based Predictive Controller, Takorn Plengsangsri Jan 2022

Control Of A Polybutylene Succinate (Pbs) Polymerization In A Semi-Batch Reactor By Neural Network Model Based Predictive Controller, Takorn Plengsangsri

Chulalongkorn University Theses and Dissertations (Chula ETD)

Polybutylene succinate (PBS) is a biodegradable plastic known for its strength and versatility in various applications. This research presents a data-driven approach to simulate temperature control in a semi-batch reactor during polymerization, the performance of the proposed approaches was compared against conventional controllers, including PID control and first-principles model MPC control. The study developed neural network model-based predictive control (NNMPC) and multiple neural network model-based predictive control (Multi-NNMPC), using Python and Tensorflow. Neural network models were trained by using a wide range of dynamic data with varying numbers of neurons in hidden layers to investigate the process dynamics under different …

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Design Of Process For Recovery Of Gold And Nickel Ions From Wastewater Of Metal Plating Process In Electronics Industry Using Hollow Fiber Supported Liquid Membrane, Wanchalerm Srirachat Jan 2022

Design Of Process For Recovery Of Gold And Nickel Ions From Wastewater Of Metal Plating Process In Electronics Industry Using Hollow Fiber Supported Liquid Membrane, Wanchalerm Srirachat

Chulalongkorn University Theses and Dissertations (Chula ETD)

In the manufacture of printed circuit boards (PCBs), electroless nickel immersion gold (ENIG) plating is widely applied. During the plating process, excess nickel and gold plating solutions, which adheres to the workpiece, is removed. As a result, economical quantities of nickel and gold ions accumulate in the rinse water baths and can then be collected. In this work, the simultaneously selective extraction and recovery of nickel and gold ions using a single-step operation of hollow fiber supported liquid membrane (HFSLM) technique was studied. Real rinse wastewater from the plating process containing trace nickel ions (Ni(II)) of 15 mg/L and gold …

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The Study Of Weave-Pattern Effect On Filtration Performance Of Woven Filter Cloths By Computational Fluid Dynamic Modeling, Wisit Bandasak Jan 2022

The Study Of Weave-Pattern Effect On Filtration Performance Of Woven Filter Cloths By Computational Fluid Dynamic Modeling, Wisit Bandasak

Chulalongkorn University Theses and Dissertations (Chula ETD)

An important global problem that has an impact on both human health and the environment is air pollution. Exercise and outdoor activities are essential for human well-being, but they can also have a detrimental effect on health and the environment. For example, PM2.5 and PM10 particles can enter the lungs and cause respiratory and cardiovascular disorders. Moreover, masks must be worn in order to stop the COVID-19 epidemic from spreading. Nevertheless, not all masks are effective in preventing viruses and air pollution. Consequently, selecting the proper mask is essential for avoiding health risks. Using the use of computational fluid dynamics, …

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Improvement Of Hydrodynamics And Heat Transfer In Biomass Fluidized Bed Combustor With Immersed Tubes Using Cfd-Dem, Krittin Korkerd Jan 2022

Improvement Of Hydrodynamics And Heat Transfer In Biomass Fluidized Bed Combustor With Immersed Tubes Using Cfd-Dem, Krittin Korkerd

Chulalongkorn University Theses and Dissertations (Chula ETD)

Computational Fluid Dynamics coupled with Discrete Element Method (CFD-DEM) has been extensively utilized for studying hydrodynamics and heat transfer in fluidization processes. This study specifically focuses on improving hydrodynamics and heat transfer in a biomass fluidized bed combustor with immersed tubes. The investigation involves the use of mixed biomass, exploring the effects of biomass types, biomass loading, and blending ratios to propose criteria for selecting suitable biomass fuel for the system. Design parameters related to the immersed tubes, such as the angle between tubes, tube diameters, and distance between tubes, were also considered. A data-driven model was developed based on …

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Chemical Constituents From The Fresh Pericarps Of Mature Mangosteen Fruit Garcinia Mangostana, Ahmad Tijani Azeez Jan 2022

Chemical Constituents From The Fresh Pericarps Of Mature Mangosteen Fruit Garcinia Mangostana, Ahmad Tijani Azeez

Chulalongkorn University Theses and Dissertations (Chula ETD)

α-Mangostin has been identified as a major chemical constituent in the pericarps of mangosteen (Garcinia mangostana Linn.) Over time, dried pericarps of mangosteen have been subjected to studies in literature. This study aimed to explore isolation of α-mangostin and other chemical constituents from the fresh pericarps of mature mangosteen fruits and investigate their relative antioxidant and anticancer activities. Repeated column chromatography on ethyl acetate and methanol extracts of fresh mature mangosteen pericarps led to the isolation of α-mangostin (33.25% of crude extracts) as the major compound, beta-mangostin (0.225%) and gartanin (7.57%). Their antioxidant scavenging activity was investigated against 2,2-diphenyl-1-picrylhydrazyl (DPPH) …

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Simultaneous Extraction And Colorimetric Detection Of Ions Using Gel Electromembrane, Ali Sahragard Jan 2022

Simultaneous Extraction And Colorimetric Detection Of Ions Using Gel Electromembrane, Ali Sahragard

Chulalongkorn University Theses and Dissertations (Chula ETD)

A total integrated electrocolorimetric sensing approach consisting of gel-based electromembrane extraction and colorimetric detection in one-step process was developed. This system was designed using colorimetric reagents preadded to the agarose gel for the determination of the following two model analytes: iodide for negative ions and nickel for positive ions. In this system, when a voltage was applied, the analytes were extracted and transferred from the sample solution (donor phase) to the gel (acceptor phase). The analytes then simultaneously reacted with the colorimetric reagents inside the gel, yielding blue and pink colors for iodide and nickel ions, respectively. These colors were …

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Fluorescent Hydrazine-Naphthalimide Encapsulated By Ethyl Cellulose For Detection Of Long-Chain Aldehydes, Faiza Lawan Isah Jan 2022

Fluorescent Hydrazine-Naphthalimide Encapsulated By Ethyl Cellulose For Detection Of Long-Chain Aldehydes, Faiza Lawan Isah

Chulalongkorn University Theses and Dissertations (Chula ETD)

One of the most common diseases globally which takes numerous lives is lung cancer. The high concentrations of aldehydes found in tobacco smoke and motor vehicle exhaust are among the contributors for lung cancer. There is a lot of interest in developing a nanosensor for identifying long-chain aldehydes. The conventional methods for detecting aldehyde are highly complex, expensive, and time-consuming. To overcome this drawback, alternative detection techniques such as fluorescence techniques are needed for the quick, easy, and affordable identification of aldehydes. Aldehyde molecules and their derivatives are often used as biomarkers to aid in the diagnosis and treatment of …

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Deep Eutectic Solvent-Coated Paper-Based Device For Colorimetric Detection Of Chromium(Vi), Fakhry Gripaldi Pandu Jan 2022

Deep Eutectic Solvent-Coated Paper-Based Device For Colorimetric Detection Of Chromium(Vi), Fakhry Gripaldi Pandu

Chulalongkorn University Theses and Dissertations (Chula ETD)

Hexavalent chromium, Cr(VI), is one of the heavy metal ions often found in the environment that is highly toxic and classified as a carcinogen. In this work, rapid screening and onsite monitoring of Cr(VI) using paper-based has been developed. Furthermore, a natural-based deep eutectic solvent, comprising choline chloride and thymol that makes it an environmentally friendly solvent, is applied as a coating medium on the test strips for qualitative and quantitative analysis of Cr(VI) for the first time. 1,5-Diphenylcarbazide was used as an indicator and complexing agent for Cr(VI). The detection was conducted by using a smartphone equipped with an …

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Use Of Layered Double Hydroxides As Ionophore For Anion Selective Electrode, Kittipong Konraeng Jan 2022

Use Of Layered Double Hydroxides As Ionophore For Anion Selective Electrode, Kittipong Konraeng

Chulalongkorn University Theses and Dissertations (Chula ETD)

Layered double hydroxides (LDHs) or hydrotalcite compounds are referred to anionic clays with specific anion adsorption and exchanging properties. These behaviors are similar to ionophores and ionic additives in ion selective electrodes (ISEs). Therefore, in this study LDHs was used to function as tailor-made ionophores for particular anions and ionic additives in ISEs. MgAl LDHs were prepared, and then modified the intercalated anions to be NO3-. The selective polymeric membrane was casted using PVC and MgAl LDHs-NO3-. The membrane containing 30%(w/w) MgAl LDHs-NO3- showed the best ISE characteristics toward NO3- with response slopes of -51.31 mV decade-1 in the concentration …

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Colorimetric Detection Of Norfloxacin And Ceftazidime By Modified Materials, Lalitphan Hongtanee Jan 2022

Colorimetric Detection Of Norfloxacin And Ceftazidime By Modified Materials, Lalitphan Hongtanee

Chulalongkorn University Theses and Dissertations (Chula ETD)

Novel approaches were developed for the colorimetric detection of norfloxacin and ceftazidime using chemically modified polymer resin and cotton sponge as sensing materials, respectively. For norfloxacin detection, the optimum condition was achieved by using a resin modified with 6.0 µM Congo red at pH 6 to extract norfloxacin in 10 mL of sample at pH 2. The reaction was completed within 15 minutes. Regarding ceftazidime detection, a cotton sponge functionalized with polyethyleneimine (PEI) was fabricated and characterized by FTIR, SEM, and ninhydrin test. To fabricate the PEI-sponge, 170 mM 3-aminopropyl triethoxysilane (APTES) was used to modify 1.0 g cotton fibers …

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Nickel Complexes Containing N4 Schiff-Base Macrocycles Dereived From Diphenylamine-2,2'-Dicarboxaldehyde For Catalytic Co2 Reduction, Methasit Juthathan Jan 2022

Nickel Complexes Containing N4 Schiff-Base Macrocycles Dereived From Diphenylamine-2,2'-Dicarboxaldehyde For Catalytic Co2 Reduction, Methasit Juthathan

Chulalongkorn University Theses and Dissertations (Chula ETD)

In this dissertation, nickel(II) complexes featuring N4-Schiff base macrocycles derived from diphenylamine-2,2'-dicarboxaldehyde (1-Ni and 2-Ni) with a new crystal structure ([2-Ni]Me) were synthesized and investigated for electrochemical CO2 reduction (ECR). Cyclic voltammetry (CV) of two nickel complexes, 1-Ni and 2-Ni, illustrated the catalytic response whereas one, [2-Ni]Me, virtually remained peak-shaped in the presence of CO2, indicating the feasibility of ECR activity for these nickel complexes. To develop heterogeneous ECR catalysts in aqueous media, all nickel complexes were adhered on N-doped graphene (NG) through non-covalent interaction, obtaining Ni@NG hybrid catalysts. The Ni@NG catalysts showed satisfactory ECR activity with the faradaic efficiency …

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