Open Access. Powered by Scholars. Published by Universities.®
- Discipline
-
- Medicine and Health Sciences (3086)
- Social and Behavioral Sciences (2614)
- Engineering (2554)
- Physical Sciences and Mathematics (1876)
- Education (1377)
-
- Arts and Humanities (1146)
- Law (897)
- Business (839)
- Medical Sciences (830)
- Chemistry (670)
- Chemical Engineering (656)
- Life Sciences (645)
- Computer Sciences (618)
- Architecture (582)
- Public Affairs, Public Policy and Public Administration (547)
- Civil and Environmental Engineering (478)
- Communication (468)
- Communication Technology and New Media (468)
- Mass Communication (468)
- Nursing (445)
- Economics (441)
- Operations Research, Systems Engineering and Industrial Engineering (375)
- Sociology (373)
- Industrial Engineering (372)
- Dentistry (357)
- Electrical and Computer Engineering (357)
- Law and Economics (344)
- Pharmacy and Pharmaceutical Sciences (342)
- Political Science (342)
- Operational Research (307)
Articles 12091 - 12120 of 15281
Full-Text Articles in Entire DC Network
Effects Of Habitat Enhancement On Bird Diversity In Kaeng Khoi District, Saraburi Province, Dijan Sunar Rukmi
Effects Of Habitat Enhancement On Bird Diversity In Kaeng Khoi District, Saraburi Province, Dijan Sunar Rukmi
Chulalongkorn University Theses and Dissertations (Chula ETD)
Various techniques of habitat enhancement have been used to increase the habitat quality, consequently enriching biodiversity and maintaining ecosystem services. This study aims to assess the effects of habitat enhancement on bird diversity, guild composition and bird usage pattern by conducting bird censuses and observations as well as arthropod samplings in the landscape-scale (LS) experiment plots and in the teak reforestation (TR) enhanced with sunflower and sunn hemp species over dry and wet seasons of 2015-2016. Sunflower treatment attracted more bird species (LS: 28, TR: 19) than sunn hemp treatment (LS: 25, TR: 15), but bird occurrence was varied based …
Taxonomy And Systematics Of Earthworm Genus Pontodrilus Perrier, 1874 In Thailand, Teerapong Seesamut
Taxonomy And Systematics Of Earthworm Genus Pontodrilus Perrier, 1874 In Thailand, Teerapong Seesamut
Chulalongkorn University Theses and Dissertations (Chula ETD)
A taxonomic study of the littoral earthworm genus Pontodrilus Perrier, 1874 was critically conducted based on material collected from marine sandy coasts along the east and west sides of the Thai-Malay Peninsula (Thailand and Malaysia) and selected localities in Japan. Comparative material from other parts of Southeast Asia, including Myanmar, Vietnam, Malaysia, Singapore and Indonesia, were also collected. Morphological examination identified almost all of the specimens as Pontodrilus litoralis, but as two morphotypes with some character differences in the diverticulum between them. A combined morphological and molecular phylogenetic analyses supported one of these morphotypes as a new species, P. longissimus. …
Suppressive Effect Of Crepidatin On Stemness Of Lung Cancer Cells, Narumol Bhummaphan
Suppressive Effect Of Crepidatin On Stemness Of Lung Cancer Cells, Narumol Bhummaphan
Chulalongkorn University Theses and Dissertations (Chula ETD)
Cancer stem cells (CSCs) have been perceived as rare populations driving cancer progression, metastasis, and drug resistance in leading cancers. The discovery of new compounds that attenuates CSCs’ properties is crucial for enabling advances in novel therapeutics to limit recurrence. We have reported the CSC-suppressing activity of chrysotoxine and crepidatin, two bibenzyl compounds isolated from Dendrobium pulchellum. Both chrysotoxine and crepidatin displayed suppression in CSC-like phenotypes, as determined in CSC-rich populations and primary CSCs in 3D culture and extreme limiting dilution assay. Individual treatment of chrysotoxine and crepidatin also affected the expression of CSC markers and associated proteins concomitantly decreased …
The Role Of Cytokine Response Signatures In The Pathogenesis Of Leptospirosis Associated Acute Kidney Injury, Nattachai Srisawat
The Role Of Cytokine Response Signatures In The Pathogenesis Of Leptospirosis Associated Acute Kidney Injury, Nattachai Srisawat
Chulalongkorn University Theses and Dissertations (Chula ETD)
Background: Acute Kidney Injury (AKI) is one of the most serious complications of leptospirosis, an important zoonosis in the tropics. Host pathogen interaction is one of the potential key factor in development of leptospirosis associated AKI. In this multicenter study, we aimed to study the association of cytokines, leptospiral burden, and anti-leptospira antibody and AKI in leptospirosis. Method: In the first cohort, patients who presented with clinical suspiciousness of leptospirosis were prospectively enrolled in 9 centers from August 2012 to November 2014. In the second cohort, we prospectively recruited patients from 15 centers from February 2016 to July 2017. The …
Molecular Epidemiology And Characterization Of Rotavirus Group A, Group C And Porcine Epidemic Diarrhea Virus In Pigs With Gastroenteritis Among The Commercial Swine Farms In Thailand, 2011-2016, Supansa Tuanthap
Chulalongkorn University Theses and Dissertations (Chula ETD)
The most frequent viruses associated with pig gastroenteritis have been previously reported as porcine epidemic diarrhea virus (PEDV) and rotavirus (RV). Rotavirus is an important cause of diarrhea in piglets and pigs worldwide, and group A (RVA) and group C (RVC) are mostly affected. In Thailand, studies on RVA and PEDV have been reported periodically, whereas information on RVC is still limited. In this study, 769 samples (fecal and intestinal content) from pigs with diarrhea were collected from pig herds located in difference provinces throughout Thailand between 2011 and 2016. The specimens were tested using virus-specific RT-PCR to detect the …
Establishment Of An In Vitro System To Screen For Substances To Improve Osteogenesis Imperfecta Osteoblasts Functions, Wandee Udomchaiprasertkul
Establishment Of An In Vitro System To Screen For Substances To Improve Osteogenesis Imperfecta Osteoblasts Functions, Wandee Udomchaiprasertkul
Chulalongkorn University Theses and Dissertations (Chula ETD)
Background: Osteogenesis imperfecta (OI) is a heritable bone disorder caused mainly by dominant mutations in genes encoding collagen-related proteins which are COL1A1 and COL1A2. Genotype-phenotype correlation has some discrepancies which lead to the difficult prediction of the clinical outcome of OI patients. We identified a child with dentinogenesis imperfecta (DI) and OI who was homozygous for c.1009G>A (p.G337S) mutation in COL1A2. Her parents were heterozygous for the mutation and had only DI. This family provides the opportunity to explore the biochemical changes which are different between the homozygous with DI and OI and the heterozygous with DI only. Methods: …
Immunity To Pertussis Vaccination, Nasamon Wanlapakorn
Immunity To Pertussis Vaccination, Nasamon Wanlapakorn
Chulalongkorn University Theses and Dissertations (Chula ETD)
Thailand has implemented universal whole cell pertussis vaccination in children for more than 35 years; nevertheless, the numbers of reported pertussis cases are still on the rise, especially among infants below one year who bear the greatest risk of severe complications. Several countries have implemented a pertussis booster during adolescence. However, data on the appropriate age groups targeted for a booster in the Thai population is limited. The increase in pertussis incidence among Thai infants warrants the need to further investigate the pre-existing maternal antibody against Bordetella pertussis (B. pertussis) antigens and the potential benefit of Tetanus toxoid-reduced dose of …
Effects Of 4,5,4'-Trihydroxy-3,3'-Dimethoxybibenzyl From Dendrobium Ellipsophyllum On Induction Of Apoptosis And Inhibition Of Cancer Stem-Like Cells In Human Lung Cancer H460 Cells, Anirut Hlosrichok
Chulalongkorn University Theses and Dissertations (Chula ETD)
Failure of current chemotherapeutic drugs leads to the recurrence of tumors and increased mortality in lung cancer patients. This study investigated 4,5,4'-trihydroxy-3,3'-dimethoxybibenzyl (TDB), a bibenzyl extracted from Dendrobium ellipsophyllum Tang and Wang as a novel anticancer agent for lung cancer. Selective anticancer activity of TDB against human lung cancer cells was demonstrated with a high half maximal inhibitory concentration (IC50) approximately > 300 µM in dermal papilla cells, while IC50 in human lung cancer H460 cells was approximately 100 ± 5.18 µM. Flow cytometry confirmed that TDB (50 µM) treatment for 24 h, caused significant early and late apoptosis but not …
Effect Of Major Triterpenoids Of Centella Asiatica On Neurite Outgrowth In Neuro-2a Cells, Nonthaneth Nalinratana
Effect Of Major Triterpenoids Of Centella Asiatica On Neurite Outgrowth In Neuro-2a Cells, Nonthaneth Nalinratana
Chulalongkorn University Theses and Dissertations (Chula ETD)
Centella asiatica has been reported to demonstrate neuroprotection and memory improvement in various animal models. Triterpenoid glycosides, madecassoside (MS), asiaticoside (AS), and their aglycones, madecassic acid (MA) and asiatic acid (AA) are considered as major neuroactive constituents in C. asiatica. In this study we aimed to compared MS, AS, MA and AA for their neurite outgrowth activities and mechanisms in Neuro-2a cells. Immunofluorescent staining against ßIII-tubulin showed that MS and AS significantly increased the percentage of neurite-bearing cells and neurite length with higher potency than MA and AA. Our mechanistic studies revealed the differences in signal activation between glycosides and …
A Study On The In Vitro Stability And Metabolism Of Curcumin Diethyl Disuccinate In Plasma, Pahweenvaj Ratnatilaka Na Bhuket
A Study On The In Vitro Stability And Metabolism Of Curcumin Diethyl Disuccinate In Plasma, Pahweenvaj Ratnatilaka Na Bhuket
Chulalongkorn University Theses and Dissertations (Chula ETD)
Stability in aqueous media such as buffers and plasma are the one of important properties of drug candidates. Curcumin diethyl disuccinate (CDD), an ester prodrug of curcumin, has been developed to improve the chemical stability of curcumin. In this study, the in vitro stability of CDD in HCl buffer (pH 1.2), acetate buffer (pH 4.5), phosphate buffer (pH 6.8, 7.4 and 8.0) and in vitro metabolism of CDD in rat, dog and human plasma were investigated at 4, 25 and 37 °C. HPLC and nonlinear regression analyses showed that the degradation of CDD in buffers was temperature-dependent and followed pseudo-1st …
Optimization Of Protein Hydrolysate Preparation From Split Gill Mushroom Schizophyllum Commune, Aunchalee Wongaem
Optimization Of Protein Hydrolysate Preparation From Split Gill Mushroom Schizophyllum Commune, Aunchalee Wongaem
Chulalongkorn University Theses and Dissertations (Chula ETD)
The optimum conditions for hydrolysate production from split gill mushroom protein using the microbial protease, Alcalase were investigated. The study was conducted using central composite design and response surface methodology. Three independent factors: hydrolysis temperature (45, 50, and 55 °C); hydrolysis time (60, 120, and 180 min); and enzyme to substrate ratio (2%, 4%, and 6% w/v) were varied, while the pH was fixed at pH 8. These three factors had a significant effect on the DH and ABTS radical-scavenging activity (p < 0.05). The optimum conditions obtained from experiments were: enzyme to substrate ratio 2%; hydrolysis time 161.4 min; and temperature 55 °C. The coefficient of determination (R2) of total protein and the IC50 value for ABTS radical-scavenging activity were 0.972 and 0.205 µg/mL, respectively, and the DH value was 50.882%. The hydrolysate was fractionated by molecular weight (MW) cut-off membranes (10, 5, 3, and 0.65 kDa). The < 0.65 kDa fraction had the highest radical scavenging ability (IC50 = 0.026 ± 0.004 µg/mL). The MW < 0.65 kDa fraction was separated by reversed-phase HPLC to yield four subfractions (F1–5). The F4 subfraction showed the highest maximum ABTS radical-scavenging activity and was selected for further analysis by quadrupole-time-of-flight-electron spin induction–mass spectrometry-based. Five antioxidant peptides were identified. In addition, the MW< 0.65 kDa fraction protected against oxidation-induced DNA damage in pBR322, pKS, and pUC19 plasmids. Furthermore, the MW < 0.65 kDa fraction, exhibited cellular antioxidant activity in a human intestinal cancer cell line (HT-29), which was dependent on the peptide concentration. These results suggested that split gill mushroom protein hydrolysate is a good source of bioactive peptides and has potential as a natural antioxidant in food production and cosmetic products.
Reaction Mechanisms Of Substrate And Inhibitor With Ns2b/Ns3 Serine Protease Of Zika Virus By Mm And Qm/Mm Simulations, Bodee Nutho
Chulalongkorn University Theses and Dissertations (Chula ETD)
Zika virus (ZIKV) infection has become a public health concern worldwide. The recent epidemiological data have revealed a possible association of ZIKV infection with neurological manifestations in both newborn children and adults. Currently, there is no anti-ZIKV drug or vaccine available for preventing or controlling ZIKV infection. An attractive drug target for ZIKV treatment is NS2B/NS3 serine protease that plays a crucial role to cleave the peptide bond during the viral replication process. Initially, the ZIKV NS2B/NS3 serine protease in complex with four peptide substrates were studied to investigate the binding recognition and protein-substrate interactions using conventional molecular dynamics (MD) …
Development And Screening Of Chalcones Against Cancer Protein Targets Using In Silico And In Vitro Techniques, Kanyani Sangpheak
Development And Screening Of Chalcones Against Cancer Protein Targets Using In Silico And In Vitro Techniques, Kanyani Sangpheak
Chulalongkorn University Theses and Dissertations (Chula ETD)
Targeted cancer therapy has become one of high potential cancer treatments. Human topoisomerase IIα (hTopoIIα) and Epidermal growth factor receptor tyrosine kinase (EGFR-TK) are proteins that play important roles on cell cycle. The hTopoIIα catalyzes the cleavage and rejoining of double-stranded DNA while EGFR function on cell signaling. Thus, the two proteins have been suggested as molecular target for the development of novel cancer therapeutics. A series of 47 chalcone derivatives was screened against hTopoIIα and EGFR-TK by in silico and in vitro techniques. Chalcone 3d showed a high cytotoxicity with IC50 values of 10.8, 3.2 and 21.1 µM against …
Extraction Of Spent Green Tea Leaves As Bioactive-Compound Source, Monsichar Yannarat
Extraction Of Spent Green Tea Leaves As Bioactive-Compound Source, Monsichar Yannarat
Chulalongkorn University Theses and Dissertations (Chula ETD)
Spent green tea leaves (SGTL) are a major contributor to the high cost of commercial tea products because of the large amount of leftover and the cost of disposal. This research investigates on the solvent and time for the extraction of SGTL that provides good yield of potential compound and to separate bioactive compounds as enrich-fractions and pure compounds. The obtained fractions were evaluated for antioxidant, antityrosinase, anticholinesterase and plant growth regulator activities. Caffeine was found in all samples. Among five extracts, the dichloromethane extract revealed high caffeine content (92.8 %peak area), while the methanol extract showed the highest five-catechin …
Production Of 1, 12- Dodecanedioic Acid By Recombinant Microbial Cytochrome P450 In Pichia Pastoris And Saccharomyces Cerevisiae, Phawadee Buathong
Production Of 1, 12- Dodecanedioic Acid By Recombinant Microbial Cytochrome P450 In Pichia Pastoris And Saccharomyces Cerevisiae, Phawadee Buathong
Chulalongkorn University Theses and Dissertations (Chula ETD)
1,12-Dodecanedioic acid (DDA) is a primary compound which is used as an intermediate precursor for production of valuable chemical products. Biosynthesis of 1,12-DDA by recombinant (r) microorganisms can be used as an alternative method to compensate several disadvantages from chemical synthesis. The purpose of this study was to clone a CYP52A17 from Candida tropicalis to produce cytochrome P450 which can terminally oxidize fatty acids to hydroxy-fatty acids and further to dicarboxylic acids (ω-oxidation). The wild type rCYP52A17 and its engineered L261S/L490S (leucine changed to encode for serine) form (rCYP52A17mut) were expressed in Pichia pastoris and Saccharomyces cerevisiae which coexpressing the …
Characterization Of Pmspӓtzle And Spipm5 From Black Tiger Shrimp Penaeus Monodon, Sittichai Boonrawd
Characterization Of Pmspӓtzle And Spipm5 From Black Tiger Shrimp Penaeus Monodon, Sittichai Boonrawd
Chulalongkorn University Theses and Dissertations (Chula ETD)
Humoral response proteins in shrimp, antimicrobial proteins (AMPs) and proteinase inhibitors, are implicated in host defenses against the pathogen infection because their expression is changed in response to microbial infection. After the pathogen infection in shrimp, the Spätzle protein is synthesized and activated the pathogenic signaling via Toll pathway by its active protein for the synthesis of AMPs. In this study, three PmSpätzle isoforms, PmSpz1, 2 and 3 genes, were identified in Penaeus monodon. The PmSpz1 gene was chosen for studied in details. Its gene was expressed in all shrimp tissues tested and in response to WSSV infection. Western blot …
Optimization Of Protein Hydrolysate Preparation And Their Angiotensin I-Converting Enzyme Inhibitory Activity From Shiitake Mushrooms Lentinula Sp., Supawee Paisansak
Optimization Of Protein Hydrolysate Preparation And Their Angiotensin I-Converting Enzyme Inhibitory Activity From Shiitake Mushrooms Lentinula Sp., Supawee Paisansak
Chulalongkorn University Theses and Dissertations (Chula ETD)
Angiotensin-I converting enzyme (ACE) is a key enzyme involved in regulating blood pressure. ACE converts angiotensin-I into angiotensin-II, which results in raised blood pressure. Inhibition of ACE leads to a decreased concentration of angiotensin-II and lowering of blood pressure. Food protein-derived ACE inhibitory peptides are considered to be a safer alternative to antihypertensive drugs. Shiitake mushrooms, one of the most consumed mushrooms in Thailand, are recognized as a nutritive food with health-stimulating properties. The aim of this study was to optimize the preparation of a shiitake-protein hydrolysate and investigate the ACE inhibitory activity of the hydrosylate. Shiitake mushrooms were hydrolyzed …
Production And Characterization Of Cutinase From Tropical Fungi And Application With Detergent For Stain And Fuzz Removal From Spun Polyester Fabrics, Taweeporn Sooksai
Production And Characterization Of Cutinase From Tropical Fungi And Application With Detergent For Stain And Fuzz Removal From Spun Polyester Fabrics, Taweeporn Sooksai
Chulalongkorn University Theses and Dissertations (Chula ETD)
Fungi were isolated from agricultural soil and plant specimens. Twenty three isolates from 44 fungal isolates were found to produce cutinase by using PCL-plate clearing assay and their cutinase activity were investigated. All the cutinase-producing fungi were cultured in liquid mineral medium (LMM) containing PCL or crude cutin extracted from papaya peels, which was a carbon source for cutinase production. Cutinase activity was assayed base on the hydrolysis of paranitrophenyl butarate (p-NPB). It was found that PBURU-T5 gave the highest cutinase activity. The isolate PBURU-T5 was selected for identification based on morphology together with comparative nucleotide sequencing from internal transcribed …
Glycation And Α-Glucosidase Inhibitors From Boesenbergia Rotunda And Lansium Parasiticum, Thammatee Potipiranun
Glycation And Α-Glucosidase Inhibitors From Boesenbergia Rotunda And Lansium Parasiticum, Thammatee Potipiranun
Chulalongkorn University Theses and Dissertations (Chula ETD)
Glycation is spontaneous non-enzymatic reaction between protein and glycation precursors; methylglyoxal (MG) that initially yields advanced glycation end-products (AGEs), which ultimately trigger to several severe complications. Therefore, the inhibition of AGEs formation is the imperative approach for alleviating diabetic complications. Moreover, one of typical diabetic therapy is α-glucosidase inhibition to reduce glucose level in bloodstream. Therefore, this research aims to study bioactivity and mechanism of natural products to inhibit glycation and α-glucosidase. From preliminary study of some phenolic compounds, flavanones from fingerroot (Boesenbergia rotunda) could inhibit glycation. The dichloromethane extract of fingerroot afforded three flavanones (pinocembrin, pinostrobin, and alpinetin), two …
Flowering Phenology And Pollination Biology Of Ceropegia Thailandica Meve And Ceropegia Suddeei Kidyoo, Chayanin Kraithep
Flowering Phenology And Pollination Biology Of Ceropegia Thailandica Meve And Ceropegia Suddeei Kidyoo, Chayanin Kraithep
Chulalongkorn University Theses and Dissertations (Chula ETD)
The flowers of the genus Ceropegia have complex structures that involve in pollination mechanism. These structres gynostegium, pollinarium and corona. Moreover, the corolla tube which is inflated at base and the corolla lobes are connate only at tip forming a cage-like structure functions as a trap. When pollinators are attracted to flower, they could be temporarily trapped inside the flower. From previous studies, there are about 18 species in Thailand. Most Thai species have flowers characterized by a long narrow corolla lobe with distinct inflated basal portion. However, some species have a short corolla tube, such as C. thailandica Meve. …
Taxonomic Revision And Pollination Biology Of Orchid Genera Crepidium Blume And Dienia Lindl. (Malaxidinae, Orchidaceae) In Thailand, Anchalee Nuammee
Taxonomic Revision And Pollination Biology Of Orchid Genera Crepidium Blume And Dienia Lindl. (Malaxidinae, Orchidaceae) In Thailand, Anchalee Nuammee
Chulalongkorn University Theses and Dissertations (Chula ETD)
The terrestrial orchid Crepidium Blume and Dienia Lindl. in Thailand were enumerated by Gunnar Seidenfaden under Malaxis with key and drawings. Because of no species descriptions in publication, it is difficult to delimit species boundary. Moreover, recent discovery of new species results in unreliable assessment of species, therefore, the taxonomic revision of Crepidium and Dienia in Thailand should be carried out. The results indicated that the column and transversal callus on labellum are taxonomically important characters to delimit these two genera. In addition, morphological characters, i.e. stem and leaf morphology, labellum auricles, margins and number of teeth on distal margin …
Reforming Regulation Of Multi-Level Marketing In Myanmar, Zeyar Nyunt Oo
Reforming Regulation Of Multi-Level Marketing In Myanmar, Zeyar Nyunt Oo
Chulalongkorn University Theses and Dissertations (Chula ETD)
The business of multi-level marketing is prohibited in Myanmar under the Notification no 46/2018. There are not only three paragraphs but also lack of the definition of MLM in this Notification. If distributors sell any product through MLM in Myanmar, they will be punished with imprisonment for a term exceeding three years under section 5 of the Myanmar Essential Goods and Services Law 2012. The study of the provisions on the business of MLM in selected ASEAN countries, Indonesia, Malaysia, Thailand, and Singapore indicates that the definition of multi-level marketing and pyramid scheme is not the same. Moreover, businessman and …
Taxonomic Revision Of The Fern Family Athyriaceae In Thailand, Puttamon Pongkai
Taxonomic Revision Of The Fern Family Athyriaceae In Thailand, Puttamon Pongkai
Chulalongkorn University Theses and Dissertations (Chula ETD)
The most up-to-date account of the Athyriaceae is in Flora of Thailand. This account includes seven genera, i.e. Athyrium, Anisocampium, Cornopteris, Deparia, Diplazium, Hypodematium and Kuniwatsukia. Previously, the taxonomic relationships among genera were ambiguous and not well understood. The existing keys and descriptions are uncertain and do not include some unknown taxa. This research aims to clarify the taxonomic status of this family and its genera based on morphological, anatomical, palynological and molecular data. The results indicated that the types and shapes of frond, scale types, sorus shapes, shapes of vascular bundle and ornamentation of spores are valuable characters for …
Simulation Of Water Effect On Biodiesel Production Using Waste Cooking Oil Via Ester-Transesterification In A Reactive Distillation Column, Ajala Anantapinitwatna
Simulation Of Water Effect On Biodiesel Production Using Waste Cooking Oil Via Ester-Transesterification In A Reactive Distillation Column, Ajala Anantapinitwatna
Chulalongkorn University Theses and Dissertations (Chula ETD)
This research investigated the effect of water content in waste cooking oil (WCO) on the performance of a reactive distillation column for biodiesel production via ester-transesterification. A mixture of triolein and oleic acid was used as a WCO model compound. Amberlyst-15 was used to catalyze esterification while CaO was used for transesterification. From Langmuir-Hinshelwood-Hougen-Watson (LHHW) kinetic model taking into account water absorption for esterification of oleic acid (FFA), biodiesel yield was decreased with increasing of water content in WCO feedstocks. On the other hand, the initial rate of transesterification was increased with increase of amount of water in WCO feedstocks …
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 …