KMITL

Permanent URI for this communityhttps://dspace.kmitl.ac.th/handle/123456789/1

Browse

Search Results

Now showing 1 - 10 of 19

Some of the metrics are blocked by your
consent settings
Characterization of dust particles generated in Thailand Tokamak-1
(2027-01-01)
Nilgumhang, Kewalee
;
Chokchaiworadilok, Sirat
;
Poolyarat, Nopporn
;
Dangtip, Somsak
;
Limsuwan, Pichet
Thailand Tokamak-1 (TT-1) is the first magnetic confinement fusion device in Thailand and the ASEAN region. During plasma operation, plasma–wall interactions (PWI) inevitably lead to erosion of the 316L stainless-steel vacuum vessel and the boronized first wall, resulting in dust generation and plasma contamination. This work investigates the morphology and elemental composition of dust particles collected from the TT-1 vacuum chamber after plasma campaigns. In this experiment, we carried out a total of 604 discharge operation shots over a period of three months, using 99.999% purity H<inf>2</inf> gas as the fuel gas and 99.999% purity He gas for Glow Discharge Cleaning (GDC). Dust was sampled from the inner surface of the vacuum vessel using carbon tape and analyzed by field-emission scanning electron microscopy (FE-SEM) coupled with energy-dispersive X-ray spectroscopy (EDS). Four primary dust morphologies were identified: (i) smooth flake-like particles, (ii) grain-crack particles with surface cracking, (iii) granular particles with fine grains distributed across the surface, and (iv) cauliflower-like structures attributed to repeated thermal cycling. EDS analysis revealed that Fe, Cr, and Ni, originating from the 316L stainless-steel wall, are the dominant metallic constituents, together with light elements such as B, C, and O associated with the boronization layer and subsequent oxidation. The presence of B- and C-rich granular dust confirms successful deposition and erosion of the boron coating used for wall conditioning. These results demonstrate that dust generated in TT-1 is a mixture of wall and boronization-layer fragments, which poses potential theoretical risks of plasma impurity accumulation, enhanced radiative losses, and compromised plasma ignition and stability in future high-performance campaigns. The present characterization provides a basis for future studies on dust transport, retention, and mitigation strategies in TT-1 and similar medium-size tokamak devices.
Some of the metrics are blocked by your
consent settings
Effect of paclobutrazol on growth retarding in potted chrysanthemum (Dendranthema grandiflora)
(2024-03-01)
Piphatwatthanakul, P.
;
Boonkamjat, T.
;
Saetiew, K.
Paclobutrazol application was compared to the control. It showed a positive influence in reducing stem height, canopy width, internode length, node number, and flower size. Besides, methods of application were insignificantly found. As for the second experiment, decreased concentrations to 0, 100, 200, 300, and 400 ppm of paclobutrazol were tested, using the same manner of application as in the first experiment. It appeared that all concentrations of paclobutrazol decreased canopy width, stem length, internode length, and node number when compared with the control treatment, similar to results of the experiment 1. Nevertheless, it occurred in Prakaimat variety that both foliar spraying and soil drenching of paclobutrazol led to increasing chlorophyll content and carotenoid level. Meanwhile, Fiona chrysanthemum responded better to foliar spraying method than of soil drenching.
Some of the metrics are blocked by your
consent settings
Mechanical, Thermal and Morphological Properties of Poly(Lactic Acid) and Poly(Butylene Adipate-co-Terephthalate) Blends with Organoclay
(2022-01-01)
Wacharawichanant, Sirirat
;
Wongpan, Krittaphorn
;
Aksornnam, Khunpat
;
Phankokkruad, Manop
This work studied the effect of nanoclay surface modified with 25-30 wt% of methyl dihydroxyethyl hydrogenated tallow ammonium (Clay-DHA) on morphological, mechanical and thermal properties of poly(lactic acid) (PLA) and poly(butylene adipate-co-terephthalate) (PBAT) blends. The PLA/PBAT (75/25 w/w) blends without and with Clay-DHA were melt mixed by an internal mixer and molded by compression method. The morphological analysis observed the phase separation of PLA/PBAT blends due to minor PBAT phase dispersed as spherical shape in PLA phase, indicating a poor interfacial adhesion between PLA and PBAT phases. The incorporation of Clay-DHA could improve the compatibility of polymer blends. The tensile testing found that the addition of Clay-DHA 1 and 3 phr increased Young’s modulus of PLA/PBAT blends. The addition of Clay-DHA decreased the strain at break of PLA/PBAT blends. The thermal degradation of PLA/PBAT blends and composites showed the similar thermal degradation process step. The addition of Clay-DHA was no effect on thermal stability and thermal properties of PLA/PBAT blends.
Some of the metrics are blocked by your
consent settings
EFFECT OF DIPPING SOLDERING ON THICKNESS AND INTERMETALLIC COMPOUND MORPHOLOGY BETWEEN Sn-3.0Cu LEAD-FREE SOLDER AND COPPER SUBSTRATE
(2022-01-01)
Mookam, Niwat
;
Kanlayasiri, Kannachai
The thickness and morphology of intermetallic compounds formed between Sn-3.0Cu lead-free solder and the copper substrate were investigated. In the experiment, the dipping soldering was performed at 350°C using Sn-3.0Cu lead-free solder for various dipping time lengths of 5, 10, 20, 50, 75 and 100s, respectively. The results indicated that η- Cu6Sn5 intermetallic phase was found to exist between the lead-free solder and the copper substrate. The formation of an ε-Cu3Sn particles on the η- Cu6Sn5 surface and grain boundary was found only when the substrate was soldered for 75 and 100s. The long soldering time and formation of ε-Cu3Sn particles resulted in the morphology of the η- Cu6Sn5 IMC changed from scallop shape to more round. Nevertheless, the thickness and morphology of intermetallic compounds was also found to be influenced by the diffusion controlled process.
Some of the metrics are blocked by your
consent settings
Sphere-like and flake-like ZnO immobilized on pineapple leaf fibers as easy-to-recover photocatalyst for the degradation of congo red
(2021-04-01)
Deebansok, Siraprapha
;
Amornsakchai, Taweechai
;
Sae-Ear, Pannagorn
;
Siriphannon, Punnama
;
Smith, Siwaporn Meejoo
This work reports immobilization of ZnO photocatalyst on very fine pineapple leaf fiber (PALFs) by a by polyelectrolyte coating method, for the removal of colored pollutants from water stream, allowing for simple recovery after use. It also emphasizes on the effect of defect structure containing in ZnO of hierarchical sphere-like and flake-like morphologies on the color removal performance. The photocatalytic activity of ZnO/PALFs for degradation of congo red (CR) dye was examined under static (dark) and UV/visible irradiation conditions, and effective color removal (>95 %) was achieved, as the results of adsorption and photo-oxidation processes. Results from photoluminescence and X-ray photoelectron spectroscopy suggested that the sphere-like ZnO, bearing zinc vacancies (VZn), zinc interstitials (Zni), singly ionized oxygen vacancies (Vo+), and oxygen vacancies (Vo), has superior photocatalytic activity up to 3.6 times compared to that of flake-like ZnO. With the recyclability up to 3 cycles (>84 % color removal efficiencies), the ZnO immobilized on PALFs have shown a great promise as an easy-to-recover photocatalyst for the removal of colored pollutants in wastewater treatment processes.
Some of the metrics are blocked by your
consent settings
Oxidation Kinetics of Soot on Acicular Mullite Membrane Filter Using Electron Microscopy and Thermogravimetric Analysis
(2020-12-01)
Saenkhumvong, Eakkawut
;
Karin, Preechar
;
Charoenphonphanich, Chinda
;
Vittayakorn, Naratip
;
Hanamura, Katsunori
This paper investigates the oxidation kinetics of carbon black on acicular mullite using thermogravimetric (TGA) and mullite microstructures by scanning electron microscopy (SEM) for the development of diesel particulate filters (DPFs). It is observed that the amount of each chemical composition strongly affects the structure of mullite. The addition of AlF<inf>3</inf> and V<inf>2</inf>O<inf>5</inf> to mullite promotes the growth of needle-shaped mullite crystals. Thermogravimetric analysis was used to investigate and characterize chemical kinetics of soot oxidation for better understanding of designs and configurations of diesel particulate filters. The mass conversion of soot on the acicular mullite (ACM) is oxidized faster than that on the mullite (ML) membrane at all temperatures examined. The calculation of apparent activation energy (E<inf>a</inf>) of soot oxidation with isothermal methods on mullite was presented. The results showed that activation energy of soot oxidation is enhanced with ACM than with ML at all temperatures examined. The average calculated apparent activation energy of soot oxidation on ACM and ML are 146.4 kJ/mole and 155.3 kJ/mole, respectively.
Some of the metrics are blocked by your
consent settings
Morphology and properties of poly(lactic acid)/ethylene-octene copolymer blends with different organoclay types
(2020-01-01)
Wacharawichanant, Sirirat
;
Sriwattana, Attachai
;
Yaisoon, Kulaya
;
Phankokkruad, Manop
This work studied the morphology, mechanical and thermal properties of poly (lactic acid) (PLA)/ethylene-octene copolymer (EOC) (80/20) blends with different organoclay types. Herein, EOC was introduced to toughening PLA by melt blending and organoclay was used to improve compatibility and tensile properties of the blends. The two organoclay types were nanoclay surface modified with aminopropyltriethoxysilane 0.5-5 wt% and octadecylamine 15-35% (Clay-ASO) and nanoclay surface modified with dimethyl dialkyl (C14-C18) amine 35-45 wt% (Clay-DDA). The organoclay contents were 3, 5 and 7 phr. Scanning electron microscope (SEM) observation results revealed PLA/EOC blends demonstrated a two-phase separation of dispersed EOC phase and PLA matrix phase. The addition of organoclay significantly improved the compatibility between PLA and EOC phases due to EOC droplet size decreased dominantly in PLA matrix, so organoclay could act as an effective compatibilizer. The incorporation of organoclay increased significantly tensile strength of PLA/EOC/organoclay composites while Young’s modulus increased with 5 phr of organoclay. The thermal stability of PLA/EOC blends did not change when compared with neat PLA, and when added Clay-ASO in the blends could improve the thermal stability of the PLA/EOC blends.
Some of the metrics are blocked by your
consent settings
Morphology and mechanical properties of poly(Lactic acid) with propylene-ethylene copolymer and α-cellulose
(2019-01-01)
Wacharawichanant, Sirirat
;
Opasakornwong, Patteera
;
Poohoi, Ratchadakorn
;
Phankokkruad, Manop
This work studied the improvement of poly(lactic acid) (PLA) properties by adding propylene-ethylene copolymer (PEC) and α-cellulose (AC). The PLA blends and composites were melt mixed by an internal mixer and molded by compression method. The morphological analysis observed the phase separation of PLA/PEC blends due to minor PEC phase dispersed as spherical shape in PLA phase, indicating a poor interfacial adhesion between PLA and PEC phases. The incorporation of AC did not improve the compatibility of polymer blends. Young’s modulus and tensile strength of PLA blends reduced with increasing amount of PEC because the elastics of ethylene molecules in PEC structure. Young’s modulus of PLA/PEC/AC composites increased with increasing AC contents. The stress at break of the PLA/PEC blends was improved with the presence of AC. The strain at break of PLA/PEC blends increased with increasing PEC contents, and the presence of AC showed the decrease of strain at break of PLA/PEC blends.
Some of the metrics are blocked by your
consent settings
Morphological and genetic characterization of marine filamentous cyanobacterium Geitlerinema isolated from Thailand
(2018-04-01)
Tinpranee, Nichanan
;
Worananthakij, Worakrit
;
Incharoensakdi, Aran
;
Phunpruch, Saranya
Geitlerinema is a dominant benthic filamentous cyanobacterium found in the Gulf of Thailand and the Andaman Sea. We investigate the diversity of Geitlerinema strains isolated from Thailand using morphological and molecular characterization. No morphological differences were observed in the Geitlerinema isolates. Nucleotide sequencing and phylogenetic analyses of the 16S rDNA, the 16S–23S rRNA internal transcribed spacer (16S–23S ITS) and the cpcB-cpcA intergenic spacer (cpcB-cpcA IGS) showed that the marine Geitlerinema isolates belong to a single cluster that includes marine Geitlerinema sp. Flo1 and Geitlerinema sp. PCC7105 but is distinct from a type species, Geitlerinema splendidum and Geitlerinema strains which were recently transferred to the genus Anagnostidinema. From our results, it is confirmed that marine Geitlerinema differs from true freshwater Geitlerinema and is proposed to be a new genus in Oscillatoriales. In addition, using random amplification of polymorphic DNA (RAPD), the marine Geitlerinema isolates in this study could be classified into eight clades; however, this classification revealed no correlation with the geographic locations.
Some of the metrics are blocked by your
consent settings
Mechanical properties and phase morphology of poly(lactic acid)/acrylonitrile-butadiene rubber/organoclay nanocomposites prepared by melt blending
(2018-01-01)
Wacharawichanant, Sirirat
;
Chomphunoi, Kasana
;
Wisuttrakarn, Chawisa
;
Phankokkruad, Manop
This work investigated the mechanical properties and phase morphology of poly(lactic acid) (PLA)/acrylonitrile-butadiene rubber (NBR) blends and nanocomposites, which prepared by melt blending in an internal mixer. The contents of NBR were 5, 10, 15 and 20 wt% and the content of organoclay was 3 phr. The impact test showed that the impact strength of PLA/NBR blends increased with an increase of NBR content and the impact strength of the blends was more than eight times by adding NBR 10 wt% when compared with neat PLA. The tensile test showed that Young's modulus and tensile strength of PLA/NBR blends and nanocomposites decreased after adding NBR and organoclay. While the strain at break of the NBR blends increased with increasing NBR content. This result is attributed to the rubber phase in NBR in a cause the increment of elongation and elasticity in PLA/NBR blends. The morphology of PLA/NBR blends observed the fractured surface was rougher than that of pure PLA. This observation indicates that the addition of NBR in PLA can change the brittle fracture of PLA to ductile fracture, which has an effect to the strain at break or elongation of PLA. However, the morphology of the PLA/NBR blends were also observed the phase separation of the dispersed NBR phase and PLA matrix phase, and appeared the voids in a polymer matrix. The addition of organoclay had an effect slightly on the morphology of the blends. From X-ray diffraction, results found that PLA/organoclay and PLA/NBR/organoclay nanocomposites showed the intercalated structure, which PLA chains were inserted into the interlayer of clay due to the increase of d-spacing.

KMITL

Browse

Filters

Settings

Sort By

Results per page

Search Results