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Articles 6181 - 6210 of 6471
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Synthesis Of Puerarin-Gold Nanoparticles For Transdermal Delivery, Kwanruen Chanpeng
Synthesis Of Puerarin-Gold Nanoparticles For Transdermal Delivery, Kwanruen Chanpeng
Chulalongkorn University Theses and Dissertations (Chula ETD)
Puerarin (Pur) is herbal medicine that its inflammatory response but low solubility to reduce activity. Thus, the aim of this study was to synthesize q188-kappa-carrageenan@Pur@gold nanoparticles (q188-κ-c@Pur@AuNPs) for enhancing solubility and transdermal delivery. The κ-c was synthesized by quaternization of κ-c with 25% (v/v) q188, and the q188-κ-c @AuNPs was prepared by reducing HAuCl4 into AuNPs by using 25% (v/v) q188-κ-c as reducing and stabilizing agents. The highest degree of quaternization (%DQ) at 21.12% was found q188 addition, which was calculated from 1H NMR. The solubility of the q188-κ-c derivatives was 43.7±0.01%, which higher than κ-c. The size of synthesized …
Effect Of Corrosion Inhibitors In Lubricant For Electronic Industry, Natclitta Maipul
Effect Of Corrosion Inhibitors In Lubricant For Electronic Industry, Natclitta Maipul
Chulalongkorn University Theses and Dissertations (Chula ETD)
The selected functional polymers and fatty esters of poly)1-butene pyrrolidone) (PP) and propylene glycol monostearate (PG) were investigated and applied to use as the corrosion inhibitors for protecting material removal during read/write head lapping processes in hard disk drive (HDD) production. Potentiodynamic polarization measurement was used to study their corrosion behaviors against antiferromagnetic materials (IrMn) which are the most sensitive materials in the head structure. Corrosion rate of PP- and PG-modified lubricants were 0.086 and 0.084 Å/min, respectively, while standard lubricant was 0.111 Å/min. Moreover, the leaching out of metallic atoms was investigated by using inductively couple plasma mass spectroscopy …
Mixed Metal Oxide Catalysts Derived From Natural Sources For Production Of Fatty Acid Methyl Esters, Wayu Jindapon
Mixed Metal Oxide Catalysts Derived From Natural Sources For Production Of Fatty Acid Methyl Esters, Wayu Jindapon
Chulalongkorn University Theses and Dissertations (Chula ETD)
The objectives of this research are to study active sites of Ca-based catalysts derived from calcite (CaCO3) and dolomite (CaMg(CO3)2), and to clarify catalytic effect of MgO in the calcined dolomite as catalyst in transesterification of palm oil with methanol. Firstly, the effects of calcination temperature on evolution of MgO in dolomite and its catalytic activity were studied. The MgO containing in the calcined dolomite was not active, while the main active site was CaO. However, Ca and Mg mixed oxides obtained from calcined dolomite had higher activity than that prepared by physical mixing in which calcite and magnesite (MgCO3) …
Hydrodeoxygenation Of Oleic Acid On Unsupported Co-Mo And Ni-Mo Sulfide Catalysts, Paphawee Sanggam
Hydrodeoxygenation Of Oleic Acid On Unsupported Co-Mo And Ni-Mo Sulfide Catalysts, Paphawee Sanggam
Chulalongkorn University Theses and Dissertations (Chula ETD)
In this research, hydrodeoxygenation (HDO) of oleic acid (model compound of palm oil) over unsupported Co-Mo and Ni-Mo sulfide catalysts was carried out in Parr reactor to produce bio-hydrogenated diesel (BHD). The effects of reaction parameters: temperature, hydrogen pressure and the mole ratio of catalysts (Ni/(Ni+Mo) or Co/(Co+Mo)) on the conversion and product yields (mainly n-C17 and n-C18 hydrocarbons) were investigated to find the optimal conditions. The results showed that high pressure favored a HDO pathway, while high temperature strongly affected to decarboxylation and decarbonylation pathways. At optimal condition as temperature of 280oC, reaction times of 6 h and hydrogen …
Preparation Of Porous Carbon From Popped Rice Via Impregnated Water Coupled With Freeze-Drying Process, Purichaya Nisawa-Anutaraphan
Preparation Of Porous Carbon From Popped Rice Via Impregnated Water Coupled With Freeze-Drying Process, Purichaya Nisawa-Anutaraphan
Chulalongkorn University Theses and Dissertations (Chula ETD)
Activated carbon is an interesting material due to its high surface area derived from the highly porous structure. This material is suitable for using as a good adsorbent in various applications such as wastewater treatment, gas absorption and medicine. Production of activated carbon typically consists of two steps which are carbonization and activation. Agricultural wastes are used as carbon sources. This research focuses on the production of activated carbon from popped rice due to its appropriate chemical and structural characteristics, including highly starch content and connected-pore structure. Therefore, it should potentially be applied to produce activated carbon if the surface …
Photooxidation Of Organosulfur Compounds Catalyzed By Iodo-Bodipy Derivatives Under Visible Light Irradiation, Piyamaporn Tangkasemsamran
Photooxidation Of Organosulfur Compounds Catalyzed By Iodo-Bodipy Derivatives Under Visible Light Irradiation, Piyamaporn Tangkasemsamran
Chulalongkorn University Theses and Dissertations (Chula ETD)
In this work, iodo-BODIPY derivatives, I-GB, 3I-GB, I-RB, were synthesized and used as photocatalysts for oxidation of organosulfurs such as thiols and thioethers into the corresponding disulfides and sulfoxides, respectively, as well as compared with benchmark photocatalyst, rose bengal. All BODIPY derivatives were successfully synthesized in good yields (36-80%) via condensation reaction between 4-iodobenzaldehyde and corresponding pyrroles, followed by oxidation with DDQ and complexation with BF3.OEt2. Among all synthesized BODIPYs, 3I-GB and 3I-RB showed relatively low quantum yield (0.053-0.054) with high singlet oxygen generation efficiency under green LED suggesting that both of them could serve as good photocatalysts for sulfur …
Development Of Hydrogen Embrittlement Resisted Pd-Cu Alloy Membrane, Ratchaneekorn Chukiatthai
Development Of Hydrogen Embrittlement Resisted Pd-Cu Alloy Membrane, Ratchaneekorn Chukiatthai
Chulalongkorn University Theses and Dissertations (Chula ETD)
The development of PdCu alloy membranes that can be used in hydrogen separation at low working temperature (<300°C) without hydrogen embrittlement problem is a very attractive topic for the petrochemical industry. Pd–Cu membranes have been prepared by electroless plating and electroplating method on stainless steel support. The compositions of the PdCu alloy membranes were related to both the metal deposition rates. The appropriate annealing temperature of Pd–Cu membranes was found at 500 °C in argon atmosphere for 24 hours to form a complete alloy material. After thermal annealing, the Cu atom was distributed in Pd alloy membrane. The surface morphology, compositions, and crystallinity of the PdCu alloy membranes were characterized using scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDS) and X-ray diffraction (XRD). The best Pd contents in PdCu alloy membrane were about 84 and 75 %at. The hydrogen flux through the PdCu alloy membrane was measured at temperature 150 to 300 °C and differential pressure 0.5 to 2.5 bar for membrane stability. The hydrogen flux increased with increasing temperature and pressure. Adding Cu atoms in Pd can reduce strain in Pd lattice structure. Both PdCu alloy membrane can be operated at the lower temperature than a critical temperature of pure Pd membrane without hydrogen embrittlement.
Effect Of Metallocene Elastomers And Screw Speed On Polypropylene Compounds: Morphological And Physical Properties, Supot Ponhan
Effect Of Metallocene Elastomers And Screw Speed On Polypropylene Compounds: Morphological And Physical Properties, Supot Ponhan
Chulalongkorn University Theses and Dissertations (Chula ETD)
Polypropylene (PP) which is widely used in automotive industries can replace engineering plastics and metals due to its outstanding mechanical properties, moldability and reduced weight. Some automotive parts such as bumper require higher impact resistance, which is the limited property of PP. The aim of this work is to improve the impact properties with balancing the stiffness-impact properties and the physical properties by blending PP with metallocence elastomer (POE) using a twin screw extruder. The effects of PP and POE type and blending ratio on the PP/POE blends properties and morphology was studied. The results showed that the impact strength …
Water/Dust Repellent Coatings For Wood Surface From 3-Aminopropyltriethoxy Silane-Quat 188, Tanate Tubtimtong
Water/Dust Repellent Coatings For Wood Surface From 3-Aminopropyltriethoxy Silane-Quat 188, Tanate Tubtimtong
Chulalongkorn University Theses and Dissertations (Chula ETD)
Wetting and dust fouling on wood surface are big problems because of hydroxyl group and static charge on its surface. These problems could be minimized by surface modification which decreasing of hydroxyl groups and increasing of positive charges on wood surface. Many researches were reported about wetting issue but there were few studies directly involved to dust problem. In this research, 3-aminopropyltriethoxy silane (APTES) and 3-chloro-2-hydroxypropyltrimethyl ammonium chloride (Q188) were used to modify hydroxyl groups on wood surface to enhance wetting and dust repellency behavior of wood. The APTES-treated woods (AW) were prepared by immersion solution method and then were …
Molecular Dynamics Of Single-Wall Carbon Nanotube Wrapped With Polypropylene, Wanwisa Panman
Molecular Dynamics Of Single-Wall Carbon Nanotube Wrapped With Polypropylene, Wanwisa Panman
Chulalongkorn University Theses and Dissertations (Chula ETD)
Nowadays, the nanocomposite materials have been widely used in various applications due to their unique properties such as thermal and electrical properties. Polymer/carbon nanotube (CNT) nanocomposite is one the important nanocomposite materials that are manufactured for improving thermal conductivity and electrical properties of polymers. Unfortunately, polypropylene (PP)/CNT preparation is difficult because of CNT dispersion and aggregation. Accordingly, amylose (AMY) and chitosan (CS) are selected in the present study in order to demonstrate how AMY and CS could diminish such problems by non-covalent modification on outer surface of single-walled CNT using molecular dynamics (MD) simulations. The MD results reveal that AMY …
Methane Adsorption By Carbon Molecular Sieve Derived From Polycarbonate And Polyaniline, Jakchai Thawornwatthanasirikul
Methane Adsorption By Carbon Molecular Sieve Derived From Polycarbonate And Polyaniline, Jakchai Thawornwatthanasirikul
Chulalongkorn University Theses and Dissertations (Chula ETD)
The adsorptions of methane by carbon molecular sieves (CMS) were investigated at 35°C and 45°C by volumetric apparatus with the pressure range from 0 to 800 psia. CMS was prepared from polymer precursors such as polycarbonate (PC) and polyaniline (PANI) by carbonization under nitrogen inert atmosphere and activation by CO2 at temperature 700, 800 and 900°C. The yield of CMS is decreased with increasing carbonization and activation temperature. The methane adsorption capacity at 35°C of CMS derived from PC is 2.82 mmol CH4/g. The methane adsorption of the samples from PC is higher than those obtained from PANI for the …
Effect Of Oxygen-Containing Functional Groups On Methane Adsorption By Activated Carbon, Kittima Dheerapreampree
Effect Of Oxygen-Containing Functional Groups On Methane Adsorption By Activated Carbon, Kittima Dheerapreampree
Chulalongkorn University Theses and Dissertations (Chula ETD)
Natural gas has been applied as a fuel for vehicle because it is cheaper and cleaner burning than other fuels. In the vehicle, natural gas is ordinarily reserved by compressing and storing under high pressure at room temperature but this method has several limitations (e.g. low energy density, high weight of tank). Therefore, a porous material with high specific surface area (e.g. activated carbon) is suggested to eliminate the limitations of natural gas storage by compression, natural gas is adsorbed at relatively low pressure and room temperature. The adsorption capacity of activated carbons is related with their physical and chemical …
The Incipient Layer Of Wax Deposit, Tunya Ketjuntiwa
The Incipient Layer Of Wax Deposit, Tunya Ketjuntiwa
Chulalongkorn University Theses and Dissertations (Chula ETD)
The formation of the incipient layer of wax deposit when waxy oil is exposed to a cold surface is studied. Using a cold-finger apparatus, the evolution of deposit thickness is monitored with a video camera, allowing one to resolve the deposit layer formation from inception up to long times where deposit thickness no longer times where deposit thickness no longer grows. Characterization of wax deposits show that incipient layer has identical composition to waxy oil, indicating that deposit is not formed by a diffusion process. Modelling shows deposit formation at the investigated conditions cannot be explained by a diffusion process.
Material Flow Analysis (Mfa) Study For Sustainable Management Of Pvc Wastes In Thailand (Phase Iii), Wikanda Khomchu
Material Flow Analysis (Mfa) Study For Sustainable Management Of Pvc Wastes In Thailand (Phase Iii), Wikanda Khomchu
Chulalongkorn University Theses and Dissertations (Chula ETD)
Polyvinyl chloride (PVC) products are used for domestic consumption more than 400,000 tons annually and tend to be increasing in Thailand. After discarded, these products will become wastes which are being accumulated and could cause several environmental problems if they are disposed by inappropriate method. In previous studies, our group investigated the material flow of PVC in Thailand to handle the PVC waste problems. Material Flow Analysis (MFA) model was developed to estimate the quantity and route of PVC wastes in Thailand. Furthermore, the primary data were collected from recycle shops and landfill sites were used to estimate the amount …
Probiotic Properties And Anti-Helicobacter Pylori Activity Of Lactic Acid Bacteria From Plant And Fermented Food Products, Sujitra Techo
Probiotic Properties And Anti-Helicobacter Pylori Activity Of Lactic Acid Bacteria From Plant And Fermented Food Products, Sujitra Techo
Chulalongkorn University Theses and Dissertations (Chula ETD)
Two hundred and thirty-eight strains of lactic acid bacteria (LAB) isolated from several plant-materials and fermented food products collected in Thailand were screening for antibacterial activity. Fifty-three strains which exhibited antimicrobial activity against Helicobacter pylori clinical strains, were selected and identified based on the phenotypic, chemotaxonomic characteristics and 16S rRNA gene sequence analysis. They were identified as Lactobacillus (Lb.) plantarum subsp. plantarum (3 strains), Lb. pentosus (10 starins), Pediococcus (P.) pentosaceus (2 strains), Lb. paracasei subsp. tolerans (1 strain), Lb. fermentum (5 strains), Enterococcus (En.) faecium (2 strains), En. casseliflavus (1 strain), Lactococcus (Lc.) garvieae subsp. garvieae (1 strain), Lc. …
Clinical Efficacy Of Biocellulose Wound Dressing Containing Silk Sericin And Polyhexamethylene Biguanide For Split-Thickness Skin Graft Donor Sites, Supamas Napavichayanun
Clinical Efficacy Of Biocellulose Wound Dressing Containing Silk Sericin And Polyhexamethylene Biguanide For Split-Thickness Skin Graft Donor Sites, Supamas Napavichayanun
Chulalongkorn University Theses and Dissertations (Chula ETD)
A biocellulose wound dressing composed of silk sericin as an accelerative wound healing component and polyhexamethylene biguanide (PHMB) as an antimicrobial agent which showed effective and safe wound treatment. A prospective, single-blinded, randomized controlled matched-pair study was designed to evaluate the safety and the clinical efficacy of the biocellulose wound dressing containing silk sericin and PHMB compared with Bactigras® in healthy volunteers (phase I clinical study) and in split-thickness skin graft (STSG) donor site wound treatment (phase II clinical study). There were 105 healthy volunteers in phase I clinical study. The results showed that the erythema and melanin levels of …
Anti-Aging Activity Evaluation Of Grammatophyllum Speciosum Extract For Development Into An Anti-Wrinkle Serum, Verisa Chowjarean
Anti-Aging Activity Evaluation Of Grammatophyllum Speciosum Extract For Development Into An Anti-Wrinkle Serum, Verisa Chowjarean
Chulalongkorn University Theses and Dissertations (Chula ETD)
Grammatophyllum speciosum Blume (Orchidaceae) is a large-sized orchid in Southeast Asia. The aim of this study was to evaluate G. speciosum pseudobulb extract for anti-aging activities, both in vitro and in vivo. In vitro anti-aging activity was performed using non-cell and cell-based assays. In vitro study, G. speciosum pseudobulb extract exhibited a high content of gastrodin, which was used as an active analytical marker. The total content of the antioxidant polyphenols in G. speciosum ethanolic extract was 48.19 ± 0.39 mg epigallocatechin gallate (EGCG) equivalent / g extract. The anti-collagenase enzyme activity of the ethanolic extract of the pseudobulb of …
Development Of Polyurethane Based Foam Dressing Impregnated With Silver Nanoparticles And Asiaticoside For Dermal Wound Treatment, Nantaporn Namviriyachote
Development Of Polyurethane Based Foam Dressing Impregnated With Silver Nanoparticles And Asiaticoside For Dermal Wound Treatment, Nantaporn Namviriyachote
Chulalongkorn University Theses and Dissertations (Chula ETD)
This study was an innovation of polyurethane foam dressing containing silver nanoparticles and asiaticoside that aimed to treat dermal wounds. It consists of three essential properties; the natural polyols containing foam dressing could absorb exudate and maintain moisture in the wound bed, the silver could prevent and kill bacteria, the asiaticoside could accelerate wound healing. The foam dressing was produced and 2% of hydrophilic natural polyols of various types added. The characteristics were evaluated. Hydroxypropyl methylcellulose (HPMC), chitosan low MW (CLMW) and sodium alginate (Alg) were selected according to their high absorption capacity, low dehydration, good mechanical strength and low …
Free Radical Scavengers From Dendrobium Palpebrae, Napat Kyokong
Free Radical Scavengers From Dendrobium Palpebrae, Napat Kyokong
Chulalongkorn University Theses and Dissertations (Chula ETD)
Phytochemical study of Dendrobium palpebrae Lindl. (Orchidaceae) afforded ten pure compounds. One of them was characterized as a new phenanthrene-phenanthraquinone derivative named dendropalpebrone, and nine known compounds were identified as gigantol, lusianthridin, nobilone, 3,7-dihydroxy-2,4,8-trimethoxyphenanthrene, 2,5-dihydroxy-4,9-dimethoxyphenanthrene, moscatilin, scoparone, 4,5,4'-trihydroxy-3,3'-dimethoxybibenzyl and dendroflorin. All of the isolated compounds were initially screened for their free radical scavenging activity via oxygen radical absorbance capacity assay, DPPH radical scavenging assay, deoxyribose degradation assay, and assay for intracellular antioxidant activity in H2O2-induced RAW 264.7 murine macrophage cells. Dendroflorin showed the most potent activity in all assays, especially in the deoxyribose degradation assay. It manifested an IC50 value …
Bioactive Compounds From Dendrobium Infundibulum, Salinee Na Ranong
Bioactive Compounds From Dendrobium Infundibulum, Salinee Na Ranong
Chulalongkorn University Theses and Dissertations (Chula ETD)
Phytochemical study of the methanol extract from Dendrobium infundibulum (Orchidaceae) led to isolation of nine pure compounds including two new compounds (dendroinfundin A and dendroinfundin B) and seven known compounds (ephemeranthol A, moscatilin, aloifol I, batatasin III, 3,3'-dihydroxy-4,5-dimethoxybibenzyl, 3,4'-dihydroxy-3',4,5-trimethoxybibenzyl and dendrosinen B). Their structures were determined from their spectroscopic data. All compounds were then examined for their lipase and alpha-glucosidase inhibitory activities. Dendrosinen B (IC50 = 295.0±37.9 µM) showed moderate inhibitory activity against lipase when compared with orlistat (IC50 = 31.4±0.6 nM). Strong anti alpha-glucosidase agents were batatasin III (IC50 = 148.8±8.4 µM) and dendrosinen B (IC50 = 213.9±2.4 µM), …
Free Radical Scavenging Compounds From Dendrobium Parishii, Virunh Kongkatitham
Free Radical Scavenging Compounds From Dendrobium Parishii, Virunh Kongkatitham
Chulalongkorn University Theses and Dissertations (Chula ETD)
In this study, the EtOAc extract of Dendrobium parishii Rchb. f. was separated to obtain two new compounds including a bibenzyl derivative, 4,3′,4′-trihydroxy-3,5-dimethoxybibenzyl, and a bibenzyl-dihydrophenanthrene derivative, (−)-dendroparishiol, and five known compounds including flavanthrinin, moscatilin, 4,5,4′-trihydroxy-3,3′-dimethoxybibenzyl, dendrocandin E and asiatic acid. The structures of all of the isolated compounds were determined by analysis of spectroscopic data (NMR and HR-ESI-MS). They were then evaluated for antioxidant activities using DPPH free radical scavenging activity, deoxyribose degradation and oxygen radical absorbance capacity assays. Among the tested compounds, (−)-dendroparishiol showed the strongest free radicals reduction and was further investigated for antioxidant activity in H2O2-induced …
Chemical Constituents And Bioactivities Of The Leaves And Stems Of Pseuduvaria Fragrans, Wongvarit Panidthananon
Chemical Constituents And Bioactivities Of The Leaves And Stems Of Pseuduvaria Fragrans, Wongvarit Panidthananon
Chulalongkorn University Theses and Dissertations (Chula ETD)
Chemical investigation of the leaves and stems of Pseuduvaria fragrans resulted in the isolation of seven pure compounds, including a new benzophenone C-glycoside named pseuduvarioside and six known compounds comprising (-)-guaiol, (+)-isocorydine, cyathocaline, isoursuline, N-trans-feruloyltyramine and N-trans-coumaroyltyramine. The structure determination of the isolated compounds was carried out by analysis of their UV, HRS-ESI-MS and NMR data in comparison with previously reported values. All the isolates were evaluated for their α-glucosidase inhibitory activity. Only N-trans-feruloyltyramine and N-trans-coumaroyltyramine exhibited strong activity with IC50 values of 3.58 µM and 0.58 µM, respectively, as compared with the drug acarbose (IC50 985.6 µM). Kinetic studies …
Anatomical And Biomechanical Factors Associated With Plantar Fasciitis In Thai Male Conscripts, Pavinee Harutaichun
Anatomical And Biomechanical Factors Associated With Plantar Fasciitis In Thai Male Conscripts, Pavinee Harutaichun
Chulalongkorn University Theses and Dissertations (Chula ETD)
Etiology of plantar fasciitis among novice conscripts is multifactorial. The combination of all potential factors should be included for multivariate analysis to determine the significant predictors. The present study aimed to identify the intrinsic predictors of plantar fasciitis among novice conscripts. Two hundred and seventy healthy male conscripts who were without lower back or lower extremity pain prior to the commencement of military training were participated in this study. Intrinsic predictors which included individual, anatomical, and biomechanical variables were assessed at baseline. After 10 weeks of training, 113 participants were assessed again and classified as having (n = 71) or …
Comparisons Of The Four Square Step Test And The Four Square Step Test On Foam Surface In Their Accuracy To Discriminate Between Elderly With And Without Fall History, Phakkanut Mathurapongsakul
Comparisons Of The Four Square Step Test And The Four Square Step Test On Foam Surface In Their Accuracy To Discriminate Between Elderly With And Without Fall History, Phakkanut Mathurapongsakul
Chulalongkorn University Theses and Dissertations (Chula ETD)
The aims of this study were 1) to investigate the intra-rater reliability, inter-rater reliability and concurrent validity of the four square step test with foam (FSST+foam) and 2) to compare the four square step test (FSST) and the FSST+foam in their accuracy for discriminating among faller elderly, non-faller elderly, and adults. Twelve participants (4 each group) were assessed by the FSST, FSST+foam, timed up and go test (TUG) and five times sit to stand test (FTSST). The intraclass correlation coefficient and correlation coefficient were calculated to determine the reliability and validity, respectively. To investigate the accuracy for discriminating between groups, …
Biomechanics Of Sit-To-Stand And Stand-To-Sit In Typical Children Aged 4 - 12 Years And Young Adults, Potjanun Mapaisansin
Biomechanics Of Sit-To-Stand And Stand-To-Sit In Typical Children Aged 4 - 12 Years And Young Adults, Potjanun Mapaisansin
Chulalongkorn University Theses and Dissertations (Chula ETD)
The aim of study is to investigate the biomechanical pattern of sit-to-stand and stand-to-sit movement in children aged 4 to 12 years and young adults. Seventy-six participants were separated into 4 groups as following: (1) 18 children aged 4-6 years; (2) 19 children aged 7-9 years; (3) 20 children aged 10-12 years; (4) 19 adults aged 18-25 years. All participants performed their preferred pattern of sit-to-stand and stand-to-sit movement. The results showed that two patterns of sit-to-stand movement were found including sit-to-stand with and without feet moving backward. Children performed sit-to-stand with and without feet moving backward while adults only …
Gas Sensing Response Of Nickel Doped Calcium Copper Titanate Thin Films Synthesized By Sol-Gel Method, Arisara Boontum
Gas Sensing Response Of Nickel Doped Calcium Copper Titanate Thin Films Synthesized By Sol-Gel Method, Arisara Boontum
Chulalongkorn University Theses and Dissertations (Chula ETD)
Nickel-doped calcium copper titanate (Ni-doped CCTO) thin films prepared by nickel oxide (NiO) and nickel (II) acetate (C4H6NiO4) have been synthesized using sol-gel method. Four layers of Ni-doped CCTO films with various nickel dopant concentrations including undoped film were deposited by a spin coating technique on silicon and alumina substrates. Each film layer was annealed at a fixed annealing temperature of 800 °C. All samples were characterized by X-ray diffraction (XRD), energy dispersive X-ray spectroscopy (EDX), X-ray photoelectron spectroscopy (XPS) field emission scanning electron microscope (FESEM). Only the doped films prepared by NiO were analyzed by Raman spectroscopy. Moreover, the …
Plasma Characteristics And Ion Etching Performance In Hard Disk Drive Slider Fabrication Processes, Napakan Wongpanit
Plasma Characteristics And Ion Etching Performance In Hard Disk Drive Slider Fabrication Processes, Napakan Wongpanit
Chulalongkorn University Theses and Dissertations (Chula ETD)
A hard disk drive (HDD) is the permanent magnetic data storage and one of the most important components of computers, electronic devices and cloud data storage service facility. The data reading and writing are operated by the reader and writer parts of HDD head or slider. These reader and writer were made of multilayer thin ilms of different materials, forming a tunneling magnetoresistive (TMR) device. In HDD production, the ion beam etching (IBE) process was used in the preparation of surface patterns and cleaning in many fabrication steps. The Monte Carlo-based simulation package, SRIM was applied to calculate the etching …
Effects Of Gamma Ray Irradiation On Structural And Optical Properties Of Csi:Tl Crystals, Poramin Sintham
Effects Of Gamma Ray Irradiation On Structural And Optical Properties Of Csi:Tl Crystals, Poramin Sintham
Chulalongkorn University Theses and Dissertations (Chula ETD)
In this research work, effects of gamma ray irradiation on structural and optical properties of CsI doped with Tl (CsI:Tl), which is a scintillator material used for radiation detector applications, were investigated by field emission scanning electron microscopy (FESEM), X-ray diffraction (XRD), UV-VIS spectroscopy and X-ray luminescence spectroscopy. The CsI:Tl crystals used in this study were grown by a modified homemade Bridgman-Stockbarger technique with CsI powder precursors purities of 99.999% and 99.9% and with the same amount of Tl in form powder of Tl. It is observed that CsI:Tl crystal grown with the 99.999% CsI powder precursor exhibited a colorless …
Effect Of Tio2 Morphology On Efficiency Of Ch3nh3pbi3 Perovskite Solar Cells, Ramon Songtanasit
Effect Of Tio2 Morphology On Efficiency Of Ch3nh3pbi3 Perovskite Solar Cells, Ramon Songtanasit
Chulalongkorn University Theses and Dissertations (Chula ETD)
A TiO2 compact (cp) layer or blocking layer (bl) plays a crucial role in a hybrid organic-inorganic lead halide perovskite solar cell (PSC) because it prevents the carrier recombination at the interface of fluorine-doped tin oxide (FTO) and perovskite layers. In this work, fabrication, characterizations of cp-TiO2 and their effects on the PSC were studied. The cp-TiO2 layers in this work were fabricated by radio frequency (RF)-magnetron sputtering method and spin coating method with various conditions. The cp-TiO2 layer was incorporated into the PSC device structure consisting of Au/spiro-OMeTAD/MAPbI3/mp-TiO2/cp-TiO2/FTO. For the sputtering method, cp-TiO2 could selectively block the transport of …
Tribological Characterization Of Lapping Lubricant In Hard Disk Drive Fabrication, Sawanee Jitphayomkun
Tribological Characterization Of Lapping Lubricant In Hard Disk Drive Fabrication, Sawanee Jitphayomkun
Chulalongkorn University Theses and Dissertations (Chula ETD)
One of the most important processes in hard disk drive fabrication is the lapping process. As two bodies are in contact, the friction occurs, and the softer material can be worn out by the harder. By using lubricant in the lapping process, it does not only reduce the friction, but it also transfers heat and captures debris away from the surface contacts. This thesis work focused on the effects of tribological parameters toward the characteristics of lubricants, using ball-on-disk tribometer. The tribological behaviors between using different base lubricants were investigated. At the same condition as final lapping process, EG-based and …