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Articles 1861 - 1890 of 2554
Full-Text Articles in Engineering
Synthesis Of Activated Carbons From Coffee Ground Residues And Their Application As Catalysts For Ethanol Dehydrogenation, Jeerati Ob-Eye
Synthesis Of Activated Carbons From Coffee Ground Residues And Their Application As Catalysts For Ethanol Dehydrogenation, Jeerati Ob-Eye
Chulalongkorn University Theses and Dissertations (Chula ETD)
In this present study, characteristics and catalytic properties of activated carbon derived from coffee ground residue, cobalt metal (Co) supported-activated carbon and various metals (Ce, Co, Cu and Ni) supported-commercial activated carbon were determined and characterized. This study was divided into three parts. Regarding to the first part, the synthesis of activated carbon catalysts derived from coffee ground residues with different methods of physical activation was investigated. The results showed that the catalyst with physically activated by CO2 for 4 hours, exhibited the best catalytic activity of ethanol dehydrogenation to acetaldehyde. In the second part, the best catalyst from the …
Simulation And Evaluation Of Butadiene Production From Ethanol Via One-Step Reaction, Jirawat Imsaard
Simulation And Evaluation Of Butadiene Production From Ethanol Via One-Step Reaction, Jirawat Imsaard
Chulalongkorn University Theses and Dissertations (Chula ETD)
1,3-butadiene is an important compound produced from the steam cracking process. Raising demand for alternatives to fossil fuels has led to an increase in bio-derived ethanol production, which can also be used as a feedstock for 1,3-butadiene synthesis. This research investigated the simulation of 1,3-butadiene production from ethanol using one-step process with 1.AI2O3/ZnO (60:40), 2.MgO-SiO2-Na2O (1:1)(0.1%) and 3.Hf2.5ZM1.6/SiO2 as heterogeneous catalysts. The process simulation was carried out using commercial Aspen plus 8.0 program and the heat utilization efficiency was evaluated by Aspen energy analyzer software. The process optimal condition sequences were identified by adjusting the separation distillation parameters which include …
Effects Of Tio2 Support And Co Addition On Ni/Tio2 Catalysts In Selective Hydrogenation Of Furfural To Furfuryl Alcohol, Kittithad Wonglekha
Effects Of Tio2 Support And Co Addition On Ni/Tio2 Catalysts In Selective Hydrogenation Of Furfural To Furfuryl Alcohol, Kittithad Wonglekha
Chulalongkorn University Theses and Dissertations (Chula ETD)
Furfuryl alcohol is an important chemical intermediate that can be converted into many value-added derivative molecules. It is typically produced by the hydrogenation of furfural using supported metal catalysts. In this work, 15%wt Ni catalysts supported on titania (TiO2) were prepared by incipient wetness impregnation method. The effects of phase composition and average crystallite sizes of TiO2 and Co addition in the range of 1-3 wt% on the catalytic properties of 15 wt%Ni/TiO2 were investigated in the selective hydrogenation of furfural to furfuryl alcohol at 50°C, 20 bar of H2, and 2 h reaction time. It was found that Ni …
Hydrothermal Carbonization Carbon-Based Acid Catalyst For Biodiesel Production, Laddawan Tumkot
Hydrothermal Carbonization Carbon-Based Acid Catalyst For Biodiesel Production, Laddawan Tumkot
Chulalongkorn University Theses and Dissertations (Chula ETD)
This study aims to synthesize the production of biodiesel (oleic acid methyl ester) by esterification in the presence of sulfonated hydrothermal carbon based catalyst under microwave irradiation. The catalyst was prepared by hydrothermal carbonization, followed by sulfonation presenting sulfonic acid group as an active site. The catalyst characterization results confirmed good microwave-absorptivity of the catalyst which can be heated directly and accelerate the reaction immediately at the surface of the catalyst. Esterification of oleic acid (OA) with methanol experiments were optimized by using response surface methodology based on central composite design. Three variables: molar ratio of methanol to OA (2.5:1-7.5:1), …
Graphene Sheets Decorated With Silver Nanoparticles As An Oxygen Reduction Reaction Catalyst For Zinc-Air Battery, Laksanaporn Poolnapol
Graphene Sheets Decorated With Silver Nanoparticles As An Oxygen Reduction Reaction Catalyst For Zinc-Air Battery, Laksanaporn Poolnapol
Chulalongkorn University Theses and Dissertations (Chula ETD)
The aim of this thesis is to develop a catalyst for the cathode of a zinc-air battery and to investigate the effects of reduced graphene oxide decorated with silver nanoparticles on the cathode in the zinc-air battery. First, reduced graphene oxide (AgNPs/rGO) was synthesized using glucose reduction at 60 degrees Celsius. Next, the structure and morphology of AgNPs/rGO were checked using X-ray diffraction (XRD). Then, transmission electron microscopy (TEM) analyzes were carried out. The amount of silver (Ag) decorate in graphene oxide was confirmed by EDX. Next, the synthesized catalysts at 3 concentration, using a rotating disk electrode (RDE), led …
Effect Of Cu Modified Tio2 Catalysts Prepared By Incipient Wetness Impregnation And Sputtering For Photocatalytic Co2 Reduction In Aqueous Solution, Nantiya Jantarasorn
Effect Of Cu Modified Tio2 Catalysts Prepared By Incipient Wetness Impregnation And Sputtering For Photocatalytic Co2 Reduction In Aqueous Solution, Nantiya Jantarasorn
Chulalongkorn University Theses and Dissertations (Chula ETD)
In this work, we investigated the photocatalytic CO2 reduction in aqueous solution and were carried out in a stirred slurry reactor using Cu/TiO2 catalysts synthesized by incipient wetness impregnation and sputtering method. Effects of Cu loading onto titania support enhancing efficiency of the photocatalytic CO2 reduction in aqueous solution under UV irradiation by a band gap energy modification appeared between valence band and conduction band are narrowed. Cu assisted a selective hydrocarbon compound, this is methane. A comparison between Cu/TiO2 catalysts synthesized by incipient wetness impregnation and sputtering method showed that both methods exhibited similar methane selectivity. Sputtered catalysts are …
Reactive Extraction Of Metal Ion And Simultaneous Stripping Using Nanofibers-Supported Liquid Membrane In A Microchannel, Nattakarn Chucherd
Reactive Extraction Of Metal Ion And Simultaneous Stripping Using Nanofibers-Supported Liquid Membrane In A Microchannel, Nattakarn Chucherd
Chulalongkorn University Theses and Dissertations (Chula ETD)
Heavy metals in wastewater resulting from industries have become a prime concern for both environmental and economic reasons. This work intends to recover ions of heavy metal from wastewater using reactive extraction by nanofibers-supported liquid membrane (NSLM) in a microchannel. The use of supported liquid membrane enables simultaneous extraction and stripping (i.e., recovery of the extractant) processes. In this study, the NSLM was applied in a microchannel to minimize mass transfer resistance, hence improving overall performance of the extraction. Copper (II) ion was used as a model ion, while di-2-ethylhexyl phosphoric acid (D2EHPA) dissolved in kerosene was used as the …
Electrode Improvement Using Diamond-Like Carbon For Electrochemical Advanced Oxidation In Diuron Degradation, Nimit Kantiyawong
Electrode Improvement Using Diamond-Like Carbon For Electrochemical Advanced Oxidation In Diuron Degradation, Nimit Kantiyawong
Chulalongkorn University Theses and Dissertations (Chula ETD)
Diuron is one of the pesticides. Its residual can contaminate natural water resource resulting in environmental and human health problems. Several processes have been used to remove diuron contamination. Nowadays, an electrochemical advanced oxidation process (EAOP) in a microchannel reactor is used to degrade diuron owing to its high efficiency. In this research, the diamond-like carbon (DLC) thin film was used as an electrochemical electrode because it has superior hardness and electrical conductivity. In this research, we have successfully synthesized the DLC thin films using graphite as target material on the surface of 304 stainless steel substrate by the direct …
Computational Fluid Dynamics Modeling Of The Climate Inside A Chicken House, Nuttaphon Kanjanaudomsuk
Computational Fluid Dynamics Modeling Of The Climate Inside A Chicken House, Nuttaphon Kanjanaudomsuk
Chulalongkorn University Theses and Dissertations (Chula ETD)
Nowadays, most of chicken products are from a closed house system. Climate inside such chicken house can significantly affect chicken welfare and its productivity. Moreover, Thailand is in a tropical region where thermal stress is easily occurred. Suitable operating condition and chicken house design can help improve interior climate which can be evaluated by computational fluid dynamics (CFD) modeling technique. In this study, realizable k-ε model, energy conservation and species transport equations were applied to simulate the air velocity, temperature and relative humidity, respectively, inside the chicken house. The model was validated with measured air velocity, temperature and relative humidity …
The Development Of Pt/Wox/Al2o3 For 1,3-Propanediol Production From Glycerol, Parama Uttraporn
The Development Of Pt/Wox/Al2o3 For 1,3-Propanediol Production From Glycerol, Parama Uttraporn
Chulalongkorn University Theses and Dissertations (Chula ETD)
In this work, the researcher studied the hydrogenolysis of glycerol to 1,3-propanediol, by compared the catalytic activity between AlOOH (boehmite) and g-Al2O3. The catalysts were prepared by wet impregnation method. To investigate the properties, catalysts were characterized by XRD, XPS, BET, H2-TPR, H2-TPD, H2-TPR, SEM-EDX, Py-IR, NH3-IR, and XAS. The type of support showed to be of significance in deciding the activity and the selectivity to 1,3-propanediol. It was found that 2%Pt/WOx/g-Al2O3 gave higher activity and selectivity of 1,3-propanediol, which due to a large amount of active site and Brønsted acid site in the catalyst. The effects of H2 pressure, …
Effect Of Metal Oxides On Zirconia For Ketonic Decarboxylation Of Methyl Stearate, Pawaphat Sartsri
Effect Of Metal Oxides On Zirconia For Ketonic Decarboxylation Of Methyl Stearate, Pawaphat Sartsri
Chulalongkorn University Theses and Dissertations (Chula ETD)
In this research, the effect of characteristics of zirconia and metal oxide modified zirconia catalysts on the catalytic performance were investigated by ketonic decarboxylation of methyl stearate to desired ketone product at the optimal condition (400°C and 1 bar). Zirconia and metal oxide modified zirconia catalysts were characterized by using X-ray diffraction (XRD), Scanning electron microscope (SEM), N2-physissorption, X-ray photoelectron spectroscopy (XPS), and IR spectra of pyridine adsorption (Pyridine-IR). The results indicated that the transition metal oxide group modified zirconia catalysts have higher contents of total Lewis acid site and oxygen vacancies site, and lower content of total Brønsted acid …
Regeneration Of Zinc Particles For Zinc-Air Battery By Spouted-Bed Electrochemical Reactor, Peerawat Puengthaijaroen
Regeneration Of Zinc Particles For Zinc-Air Battery By Spouted-Bed Electrochemical Reactor, Peerawat Puengthaijaroen
Chulalongkorn University Theses and Dissertations (Chula ETD)
Zinc-air batteries are a promising energy storage system due to its high energy density, low toxicity, and low flammability. They are currently used commercially in low-current devices. Batteries for high-current applications are constructed with zinc particles for increased specific surface areas. Nevertheless, the regeneration of zinc particles from dissolved zincate ions in spent electrolytes has been relatively neglected. We fabricate and study a spouted-bed electrochemical reactor for the regeneration of zinc particles from spent electrolytes. The reactor measures 220 mm high and 130 mm wide with copper as a cathode and stainless steel as an anode. The reactor is separated …
Dual-Electrolyte System For Suppressing Corrosion Of Aluminum Electrode In Aluminum-Air Flow Battery, Pemika Teabnamang
Dual-Electrolyte System For Suppressing Corrosion Of Aluminum Electrode In Aluminum-Air Flow Battery, Pemika Teabnamang
Chulalongkorn University Theses and Dissertations (Chula ETD)
Aluminum-air batteries have received considerable attention as an electrical power source due to their theoretical specific capacity reaching 2.98 Ah/g. Further, Al-air batteries are abundant and low cost. On the other hand, the aluminum in the batteries has a problem, such that it is subject to self-corrosion in alkaline. Herein, this work concentrates on the aluminum's corrosive behavior and self-corrosion in methanol-3M KOH mixed solution containing different percentages of deionized water i.e. (0, 5, 10 and 20)%wt, using electrochemical (half-cell testing). The aluminum-air battery consists of: aluminum anode | anolyte | anion exchange membrane | catholyte | air cathode. The …
Reaction Mechanism And Pathway For The Selective Photocatalytic Hydrogenation Of Nitroaromatics Over Tio2 In Alcohols, Pimchanok Nakchuai
Reaction Mechanism And Pathway For The Selective Photocatalytic Hydrogenation Of Nitroaromatics Over Tio2 In Alcohols, Pimchanok Nakchuai
Chulalongkorn University Theses and Dissertations (Chula ETD)
This research investigated the mechanism and photocatalytic performance of the selective photocatalytic hydrogenation of different nitroaromatics (Ar-NO2) in several alcohols under UV light using P25-TiO2 at room temperature and atmospheric pressure. The effect of Pt-deposited P25-TiO2 on the photocatalytic performance was also studied. Ar-NO2 was converted to aminoaromatics (Ar-NH2) with high Ar-NO2 conversion and Ar-NH2 selectivity at nearly 100%. The amounts of Ar-NH2 were proportional with carbonyl compounds at the ratio around 1:3. Acetaldehyde, acetone, and butanone were produced by oxidation of ethanol, 2-propanol, and butanol, respectively. Ethanol exhibited the fastest completed Ar-NO2 conversion due to the most efficient formation …
Oxidative Dehydrogenation Of Ethanol To Acetaldehyde Over Magnesium Aluminium Layered Double Hydroxides Catalyst, Piriya Pinthong
Oxidative Dehydrogenation Of Ethanol To Acetaldehyde Over Magnesium Aluminium Layered Double Hydroxides Catalyst, Piriya Pinthong
Chulalongkorn University Theses and Dissertations (Chula ETD)
In this research, the characteristic and catalytic activity of Mg-Al LDH and their metal-modified mixed oxide were investigated. This research was divided into three parts. In the first part, the effect of calcination temperature on catalytic performance via oxidative dehydrogenation of ethanol was elucidated. The results showed that calcination temperature affected the characteristic of Mg-Al LDH, especially basicity. Moreover, the calcination temperature also affected the catalytic performance on oxidative dehydrogenation of ethanol over Mg-Al LDH. The result was consistent with the basicity of catalysts. In the second part, the Mg-Al mixed oxide derived from calcination of Mg-Al LDH was modified …
Effects Of Immobilization Of Methylalumoxane On Cellulose Support On Ethylene Polymerization Behaviors., Praonapa Tumawong
Effects Of Immobilization Of Methylalumoxane On Cellulose Support On Ethylene Polymerization Behaviors., Praonapa Tumawong
Chulalongkorn University Theses and Dissertations (Chula ETD)
The way to improve the physical properties of polyethylene is done by adding nano-sized filler during the synthetic process. These can be commonly achieved by in situ polymerization. These studies are divided into two parts in this research. Firstly, it investigated the effect of types and amounts of cocatalyst and scavenger of zirconocene catalyst on ethylene polymerization behaviors. In fact, methylalumoxane (MAO) and triethylaluminum (TEA) were used as cocatalyst and scavenger, respectively. The ratios of [Al]MAO/[Zr]cat and [Al]TEA/[Zr]cat were varied during the in situ polymerization of ethylene. The polymerization was performed in a semi-batch autoclave reactor under adiabatic operation at …
Development Of Suture Pad From Silk-Reinforced Polydimethylsiloxane Composite, Radhitya Banuaji Prastowo
Development Of Suture Pad From Silk-Reinforced Polydimethylsiloxane Composite, Radhitya Banuaji Prastowo
Chulalongkorn University Theses and Dissertations (Chula ETD)
The aim of this research is to investigate the mechanical properties of polydimethylsiloxane reinforced with short silk fibers for suture pad application. The effect of aspect ratio and fibers content of the polydimethylsiloxane reinforced with silk fibers on the properties was evaluated. From the results, tensile modulus and tensile strength of polydimethylsiloxane reinforced with different aspect ratio were increased with increasing aspect ratio and fibers content. The composite with the addition of silk fiber produces higher tear resistance with suture thread compared with pure polydimethylsiloxane. Furthermore, the hardness of polydimethylsiloxane reinforced with short silk fibers was improved with the addition …
Design Of Solid Oxide Fuel Cell-Molten Carbonate Fuel Cell Combined System For Power Generation And Carbon Dioxide Emission Reduction, Prathak Jienkulsawad
Design Of Solid Oxide Fuel Cell-Molten Carbonate Fuel Cell Combined System For Power Generation And Carbon Dioxide Emission Reduction, Prathak Jienkulsawad
Chulalongkorn University Theses and Dissertations (Chula ETD)
This research concentrates on the design and performance analysis of a solid oxide fuel cell (SOFC) and a molten carbonate fuel cell (MCFC) integrated system with using methane as fuel. Because SOFCs cannot completely use their fuel, there is remaining fuel leaving the system. In addition, the exhaust gas from an SOFC can be directly fed into an MCFC. The integrated fuel cell system shows an electrical efficiency of 55.22%, which is higher than a single fuel cell system. Fuel utilization of both fuel cells, SOFC temperature dramatically affect the performance of the integrated system. Four configurations were next proposed …
Effect Of Calcination Conditions Of P25-Tio2 On Photocatalytic Selective Hydrogenation Of 3-Nitrostyrene, Saknarin Chaitaworn
Effect Of Calcination Conditions Of P25-Tio2 On Photocatalytic Selective Hydrogenation Of 3-Nitrostyrene, Saknarin Chaitaworn
Chulalongkorn University Theses and Dissertations (Chula ETD)
In this work, we investigated the effect of calcination of nanocrystalline commercial titanium dioxide catalyst (P25) on photocatalytic selective hydrogenation of 3-nitrostyrene. TiO2 supports were calcined under air, hydrogen and nitrogen atmosphere at various temperatures around 600 to 900°C for 5 hours. In order to investigate characteristic and catalytic properties of TiO2 after treatment, treated-TiO2 were analyzed by using X-ray diffraction (XRD), N2-physisorption, X-ray photoelectron spectroscopy (XPS), UV-Vis spectroscopy (UV-Vis), photoluminescence spectroscopy (PL), thermogravimetric analysis (TGA), scanning electron microscope (SEM). Photocatalytic hydrogenation performance of treated-TiO2 were tested under UV light irradiation. The 3-nitrostyrene consumption was linearly related to the photoluminescence …
Synthesis Of Black Titanium Dioxide And Effect Of Calcination Conditions And Reducing Agent On Photocatalytic Degradation Of Methyl Orange, Saran Saensook
Synthesis Of Black Titanium Dioxide And Effect Of Calcination Conditions And Reducing Agent On Photocatalytic Degradation Of Methyl Orange, Saran Saensook
Chulalongkorn University Theses and Dissertations (Chula ETD)
This research studied the synthesis and application of black titanium dioxide in the photocatalytic degradation of methyl orange (MO). First, titanium dioxide was prepared via a sol-gel method. Then sodium borohydride was used as the reducing agent in order to synthesize black titanium dioxide. Thus, a 2x2x3 factorial experimental design was employed to assess the significance of the following three factors: (A) calcination temperature (400 and 500 °C); (B) calcination time (5 and 10 h); and (C) the molar ratio of NaBH4 to TiO2 used (0:1, 0.5:1, and 1:1). The removal of MO under UV and visible light were the …
The Effect Of Mcm-41 Addition To Pva/Pan/Pvp Polymer Electrolyte For Zinc-Air Batteries, Sirinuch Nanthapong
The Effect Of Mcm-41 Addition To Pva/Pan/Pvp Polymer Electrolyte For Zinc-Air Batteries, Sirinuch Nanthapong
Chulalongkorn University Theses and Dissertations (Chula ETD)
A membrane separator is one of the main components in zinc-air batteries playing an important role in controlling the mass transfer for the electrochemical reaction in the battery which determines the battery performance. This work aimed to develop a new membrane separator for the zinc-air battery. Polyvinyl alcohol (PVA), polyacrylonitrile (PAN), polyvinylpyrrolidone (PVP), and their blends were used for the fabrication of separator in this work. In addition, an inorganic nanoparticle with high hydroxide content such as MCM-41 was also applied as the filler for the polymers. The results revealed that the addition of PAN in PVA enhanced the electrolyte …
Application Of Amine-Functionalized Titanium Dioxide Wrapped In Reduced Graphene Oxide In Photocatalytic Degradation Of Methylene Blue, Sirinya Kanjanapanasont
Application Of Amine-Functionalized Titanium Dioxide Wrapped In Reduced Graphene Oxide In Photocatalytic Degradation Of Methylene Blue, Sirinya Kanjanapanasont
Chulalongkorn University Theses and Dissertations (Chula ETD)
This research investigated the effect of reduced graphene oxide (rGO) addition to amine-functionalized titanium dioxide (APTMS-TiO2). The loading amount of rGO was varied from 0 to 0.05 %wt. Also, the effect of the amount of 3-aminopropyltrimethoxysilane (APTMS) was studied. To synthesize TiO2/rGO catalysts, the amount of APTMS was varied at 2.21 and 22.1 mmol. TiO2 catalyst was synthesized via a sol-gel method. Next, the surface of TiO2 was modified with APTMS by refluxing. Then graphene oxide was wrapped around APTMS-TiO2 and was reduced to rGO using hydrazine and ammonia. In the experiment, the catalyst was dispersed in methylene blue solution …
Effect Of Ceo2 And La2o3 Promoters On Ni/Al2o3 Oxygen Carrier Performance In Chemical Looping Steam Reforming Of Ethanol For Hydrogen Production, Supalak Isarapakdeetham
Effect Of Ceo2 And La2o3 Promoters On Ni/Al2o3 Oxygen Carrier Performance In Chemical Looping Steam Reforming Of Ethanol For Hydrogen Production, Supalak Isarapakdeetham
Chulalongkorn University Theses and Dissertations (Chula ETD)
The effects of Ce and/or La on NiO/Al2O3 were studied in chemical looping steam reforming of ethanol. Oxygen carriers (OCs) were prepared by wet impregnation method and characterized by various techniques. The redox test was performed by alternating between fuel feed (FFS) and air feed step (AFS) at 500oC. It was found that Ce- and La-doped improved the OCs' properties. A suitable amount of Ce- and La-doping helped increase carbon tolerance due to oxygen storage capacity and mobility. The solubility limit was found at 50 mol% La in solid solution. At higher La-doping, La2O3 dispersed on the surface and adsorbed …
Design And Performance Evaluation Of Integrated System Of Hydrotreating And Hydrogen Generation For Bio-Hydrogenated Diesel Fuel Production From Palm Oil, Siriporn Boonsuk
Design And Performance Evaluation Of Integrated System Of Hydrotreating And Hydrogen Generation For Bio-Hydrogenated Diesel Fuel Production From Palm Oil, Siriporn Boonsuk
Chulalongkorn University Theses and Dissertations (Chula ETD)
This research studied the simulations of the integrated systems between of hydrotreating and hydrogen generation with various selectivity of deoxygenation (DO) pathways (i.e. decarboxylation (DCO2), hydrodecarbonylation (HDCO), and hydrodeoxygenation (HDO)). Two integrated systems were proposed i.e. 1) integrated system between single-step hydrotreating and propane steam reforming (as called "single-step integrated system") and 2) integrated system between two-step hydrotreating (hydrolysis+DO) and glycerol steam reforming (as called "two-step integrated system"). Results revealed that, among DO pathways, DCO2 exhibited the lowest total minimum energy requirement (total MER) and the highest total efficiency for both integrated systems mainly due to lower electricity requirement to …
Improving The Efficiency Of Dye-Sensitized Solar Cells With Ultrasonic Spray-Coated Tio2 Electrode That Was Modified By Mno2, Coo, Or Sno2, Supasun Thanadvanichkul
Improving The Efficiency Of Dye-Sensitized Solar Cells With Ultrasonic Spray-Coated Tio2 Electrode That Was Modified By Mno2, Coo, Or Sno2, Supasun Thanadvanichkul
Chulalongkorn University Theses and Dissertations (Chula ETD)
This research investigated the modification of TiO2 electrode by adding the second metal oxide, namely, manganese dioxide (MnO2), cobalt oxide (CoO), or tin dioxide (SnO2) use in for dye-sensitized solar cell (DSSCs). TiO2 and modified TiO2 sols were synthesized via sol-gel methods. The sols were sprayed 500 times onto the fluorine-doped tin oxide glass substrates as a thin film using an ultrasonic spray coater. Finally, the thin film electrode was calcined at 400ºC for two hours. The amount of MnO2, CoO, or SnO2 was varied at 0, 0.1, 0.5, 1.0, and 3.0%wt. The photovoltaic efficiency of DSSCs was measured using …
Preliminary Study On Synthesis And Characterization Of The Star-Shaped Poly (Ethylene Glycol) Through Polycondensation Reaction, Tanchanok Wongkhan
Preliminary Study On Synthesis And Characterization Of The Star-Shaped Poly (Ethylene Glycol) Through Polycondensation Reaction, Tanchanok Wongkhan
Chulalongkorn University Theses and Dissertations (Chula ETD)
The synthesis of star-shaped poly(ethylene glycol) was synthesized from pentetic acid (PA) and poly(ethylene glycol) (PEG) by polycondensation reaction in order to solve the problem of the melt strength of the molten polymer of poly(lactic acid). In this study, the star-shaped poly(ethylene glycol) were synthesized with a different molecular weight of neat poly(ethylene glycol) of 200, 400 and 600 g/mol. After that, the chemical structure of product-PEG was investigated by FTIR and NMR techniques. FTIR spectra of the product-PEG exhibited carbonyl peak due to the reaction between hydroxyl groups of PEG and carboxyl groups of PA. The NMR spectra of …
Lactic Acid Production From Glucose By Using Divalent Transition Metal Oxide Catalyst On Magnesium Oxide Support Without Alkaline Solution, Tanyatorn Udomcharoensab
Lactic Acid Production From Glucose By Using Divalent Transition Metal Oxide Catalyst On Magnesium Oxide Support Without Alkaline Solution, Tanyatorn Udomcharoensab
Chulalongkorn University Theses and Dissertations (Chula ETD)
This research was studied the effects of the type of divalent metal oxide (Cu, Co, Ni, and Zn) supported on magnesium oxide catalyst using the hexadecyltrimethylammonium bromide (CTAB) as the capping agent with metal loading at 1.5, 5, and 10 mmol/gram-catalyst on lactic acid production from glucose. To achieve the lactic acid production of lower reactor corrosion rate and being environmentally friendly, the reaction was performed in an alkali additive-free environment. The catalysts were synthesized by hydrothermal method and characterized by various techniques. The XRD pattern of spent CuCTAB/MgO and CoCTAB/MgO catalyst showed the reduced metal species indicated the used …
Effect Of Tio2 Polymorphs And Crystallite Size On The Catalytic Properties Of Pt/Tio2 In The Selective Hydrogenation Of Furfural To Furfuryl Alcohol, Thunyaporn Kaewla-Ueat
Effect Of Tio2 Polymorphs And Crystallite Size On The Catalytic Properties Of Pt/Tio2 In The Selective Hydrogenation Of Furfural To Furfuryl Alcohol, Thunyaporn Kaewla-Ueat
Chulalongkorn University Theses and Dissertations (Chula ETD)
Furfuryl alcohol (FA) is an important intermediate for the manufacturing of many fine chemical products such as furan, resin, vitamin C, and lysine. In this research, the selective hydrogenation of furfural to FA was carried out in a batch reactor at 50ºC, 20 bar H2 and 2 h reaction time using Pt (0.5 wt. %) on TiO2 support. The Pt/TiO2 catalysts were prepared by the incipient wetness impregnation on different commercial TiO2 polymorphs and different temperatures calcined TiO2 sol-gel. Among the commercially available TiO2, it was found that Pt supported on P25 exhibited the highest furfural conversion and selectivity of …
Analysis Of Cracked Body Repaired By Adhesively Bonded Patches By Bem-Fem Coupling, Binh Viet Pham
Analysis Of Cracked Body Repaired By Adhesively Bonded Patches By Bem-Fem Coupling, Binh Viet Pham
Chulalongkorn University Theses and Dissertations (Chula ETD)
This thesis presents an efficient numerical technique capable of handling the stress analysis of three-dimensional cracked bodies strengthened or repaired by adhesively bonded patches. The proposed technique is implemented within the framework of the coupling of the weakly singular boundary integral equation method and the standard finite element procedure. The former is applied to efficiently treat the elastic body containing cracks whereas the latter is adopted to handle both the adhesive layers and the patches. The approximation of the near-front relative crack-face displacement is enhanced by using local interpolation functions that can capture the right asymptotic behaviour. This also offers …
The Relationship Of Influential Factors On Material Management Effectiveness In Building Construction Projects: Case Study In Vietnam, Bao Van Pham
Chulalongkorn University Theses and Dissertations (Chula ETD)
The improvement of management processes in construction could be seen as one of the important keys to project success in which material management should be appropriately taken into consideration. Although many previous research studies have examined the components of construction material management, the relationship of factors influencing material management effectiveness has not been explored. This study was carried out to identify influential factors on material management effectiveness and develop a model to explain the relationships between these factors and the effectiveness of material management based on practical projects. The research method included the collection of contractors' opinions in building projects …