KMITL

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

Browse

Search Results

Now showing 1 - 6 of 6

Some of the metrics are blocked by your
consent settings
A Study on Curing Temperature and Fracture Mechanism of Carbon and Glass Fiber Reinforced Polymers Using an Electron Microscopy
(2021-06-01)
Man, Tial Cuai
;
Karin, Preechar
;
Lin, Ye Htet
;
Larpsuriyakul, Patcharee
;
Ohtake, Naoto
The morphology and nanostructure of carbon and glass fiber are investigated by using XRD, SEM and TEM analysis. The composites are divided into three groups which consists of “without post-curing”, “post-cured at 80 °C for 6 hrs” and “post-cured at 120 °C for 3 hrs” to investigate curing temperature effect. The mechanical properties of composites are tested in the indentation, tensile, and flexural machine with ASTM standard. According to the results, the hardness of post-curing of carbon fiber reinforced polymer (CFRP) and glass fiber reinforced polymer (GFRP) are increased approximately three-times and 5 % compared to with and without post-curing process. The tensile strength of CFRP and GFRP are approximately 458 MPa and 385 MPa, while post-cured at 120 °C for the three-hour results are 490 MPa and 433 MPa respectively. In contrast, composites of treated fiber are not improved mechanical strength significantly for CFRP, while GFRP are slightly increased by 7 %. On the other hand, the flexural strength of treated carbon and glass fiber of composite are increased to 3 % and 15 % respectively. Higher temperature and treated fiber composites of carbon fiber are not significantly improved because high temperature curing and treated fiber created more porous to occur fracture internally.
Some of the metrics are blocked by your
consent settings
Effect of Soot Particle Size on Four Ball Metallic Wear Using Electron Microscopy Image Analysis
(2020-06-01)
Karin, Preechar
;
Amornprapa, Warawut
;
Watanawongskorn, Park
;
Saenkhumvong, Eakkawut
;
Charoenphonphanich, Chinda
The impact of soot primary nanoparticles affecting metal wear was investigated. The commercial Carbon Black (CB) with different primary particle sizes were mixed with the engine oil for simulating soot contamination. The physical properties of carbon black including density and hardness were calculated using Transmission Electron Microscopy (TEM) image analysis. The metallic wear test was evaluated by using a Four-ball wear tester. After the tests, the ball surfaces were inspected by utilizing High-Resolution Optical Microscope (OM), Scanning Electron Microscope (SEM) and Energy Dispersive X-ray spectroscopy (EDX) analysis. Based on a Four-ball wear test, the 1 % by weight of carbon black contamination shows a bit higher average wear scar diameter (WSD), but the surface roughness is reduced. SEM micrograph of metallic wear scar for the engine oil without soot shows the area of grooves, plastic deformation and subsurface crack. On the other hand, when carbon black is added to the oil, it can be seen that there are many deep grooves along with the sliding direction. The relationship of calculated oil film thickness, primary nanoparticle size distribution, carbon atom density of soot and hardness is clearly explained metallic wear mechanisms.
Some of the metrics are blocked by your
consent settings
Investigation on influence of seeding layer on morphological properties of ZnO-based nanostructure prepared by hydrothermal process
(2018-01-01)
Chongsri, Krisana
;
Boonyarattanakalin, Kanokthip
;
Pecharapa, Wisanu
In this present work, bare ZnO low-dimensional structures were synthesized by hydrothermal process with crystal growth assistance using seed layers. Different seeding layer species including ZnO and Ga-doped ZnO films prepared by sol-gel dip coating were introduced onto the substrate before the hydrothermal growth of ZnO-based nanostructures. Zn(NO<inf>3</inf>)<inf>2</inf> and GaN<inf>3</inf>O<inf>9</inf> were utilized as Zn and Ga source during hydrothermal process. The influence of seeding layer types on morphological and shapes of the hydrothermally grown nanostructures have been extensively scrutinized by Field emission scanning electron microscope (FE-SEM), X-ray diffraction (XRD) and optical spectroscopy. It was revealed that different morphologies and exceptional shapes in form of nanorods of ZnO-based nanostructures were obtained as different seeding layers were introduced. More detailed studies for clarification of seed layer effect on the growth of ZnO-based nanostructures are mentioned and discussed.
Some of the metrics are blocked by your
consent settings
Hydrothermal synthesis and characterization of ZnO:F nanorod structure
(2016-01-01)
Sinornate, Wuttichai
;
Chongsri, Krisana
;
Pecharapa, Wisanu
F-doped ZnO nanorod structures were synthesized via hydrothermal process with variation of doping content starting from zinc nitrate solution and zinc oxide thin film used as seeding layer. The zinc oxide seeding film was fabricated by spin coating on glass substrate using zinc acetate precursor and annealed at 500 °C for 2 h. Relevant properties of ZnO:F nanorod structures were characterized by scanning electron microscope (SEM), X-ray diffraction (XRD), energy-dispersive X-ray spectroscopy (EDX) and UV-VIS spectrophotometer. Corresponding results indicated that ZnO:F nanorod array, grown in (002) plane, has the characteristics of good crystallinity. In addition, this study showed that ZnO:F nanorod with exceptional structure can be obtained by hydrothermal process, operated at proper treatment time, temperature and F-doping content.
Some of the metrics are blocked by your
consent settings
Nanocrystalline diamond films deposited by two-step approach from CH4/H2 microwave plasma: The influence of reactor pressure
(2013-08-30)
Khlayboonme, S. T.
;
Thowladda, W.
The morphology, growth rate and atomic-bonding structure of nanocrystalline diamond films deposited on Si substrates were investigated under various pressures of the reactor. The films were deposited by CH<inf>4</inf>/H<inf>2</inf> microwave plasma with two-step deposition and H<inf>2</inf>-plasma cleaning processes. The pressures of 1, 2, 5, 9, and 25 kPa were used for deposition. In situ gas-phase species, including electron density, were monitored by an optical spectrometer and impedance analyzer. The films were characterized by SEM, Raman microscope, and white light reflectrometer. When the pressure increased, the surface smoothness and diamond grain size increased, amorphous carbon content decreased, and the intensity ratio of CH/H<inf>β</inf> for the growth step increased. The growth rate was in proportional to the ratio of CH/H<inf>β</inf> for the nucleation step but in inverse proportion to the electron density. The growth rates decreased from 370 nm/h for 1 kPa to 320 nm/h for 2 kPa. After that, the growth rate rapidly increased to 460 nm/h for 9 kPa, but it gradually decreased to 450 nm/h for 25 kPa. The film refractive indices were 2.16 for 5 kPa, 2.21 for 9 kPa, and 2.38 for 25 kPa. The films grown under 1 and 2 kPa showed highly light absorption. © (2013) Trans Tech Publications, Switzerland.
Some of the metrics are blocked by your
consent settings
Photocatalysis of heat treated sodium- and hydrogen-titanate nanoribbons for water splitting, H2/O2 generation and oxalic acid oxidation
(2013-04-09)
Kiatkittipong, Kunlanan
;
Iwase, Akihide
;
Scott, Jason
;
Amal, Rose
The photocatalytic activity of sodium titanate (Na<inf>1.48</inf>H<inf>0.52</inf>Ti<inf>3</inf>O<inf>7</inf>), sodium hexatitanate (Na<inf>2</inf>Ti<inf>6</inf>O<inf>13</inf>), and hydrogen titanate (H<inf>2</inf>Ti<inf>3</inf>O<inf>7</inf>) nanoribbons and anatase TiO<inf>2</inf> nanorods were compared for water splitting, oxalic acid photodegradation and H<inf>2</inf> and O<inf>2</inf> generation using sacrificial agents. The intrinsic properties of the materials were found to affect their performance depending on the particular reaction system. The Na<inf>2</inf>Ti<inf>6</inf>O<inf>13</inf> nanoribbons, in the presence of RuO<inf>2</inf> co-catalyst, outperformed the anatase nanorods, for the water splitting reaction, generating over 10 times more H<inf>2</inf>/O<inf>2</inf>. This was thought to derive from their tunnel-like structure which provided better electron/hole separation when compared with TiO<inf>2</inf>. However, the efficient holes and electrons scavenging in the presence of sacrificial agents, methanol or AgNO<inf>3</inf>, to generate H<inf>2</inf> or O<inf>2</inf>, respectively, overwhelmed the tunnel-like structure effect. In this case photoactivity was governed by the crystal structure, with observed decreasing activity in the order TiO<inf>2</inf>>Na<inf>2</inf>Ti<inf>6</inf>O<inf>13</inf>>H<inf>2</inf>Ti<inf>3</inf>O<inf>7</inf>~Na<inf>1.48</inf>H<inf>0.52</inf>Ti<inf>3</inf>O<inf>7</inf>, and by the band gap of the semiconductor which determined its capacity to absorb photons in producing electron/hole pairs. © 2013 Elsevier Ltd.

KMITL

Browse

Filters

Settings

Sort By

Results per page

Search Results