Kitiwan, Mettaya

Preferred name

Kitiwan, Mettaya

Alternative Name

Kitiwan, M.

Main Affiliation

School of Science

mettaya.ki@kmitl.ac.th

Now showing 1 - 8 of 8

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Effects of AlN on the reactive sintering of porous Al2TiO5composites
(2020-01-01)
Kitiwan, Mettaya
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Kongsak, Mongkol
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Atong, Duangduen
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Wakui, Yoshito
The porous Al2TiO5/Al2O3 composites were fabricated by reactive sintering at 1500-1700 °C in nitrogen atmosphere. The starting materials Al2O3 and TiO2 were mixed in an equimolar ratio and the addition of AlN was 5-40 mol%. The effects of AlN content and sintering temperature on phase composition, linear shrinkage, pore sized distribution, porosity and microstructure were investigated. The XRD results showed that the composites mainly consist of Al2TiO5 while the peak intensity of Al2O3 increased with AlN content. The median pore sizes decreased with increasing AlN content and were in the range of 2- 6 lm, 1-2 lm, 0.4-0.7 lm, and 0.3-0.5 lm for composites using 10, 20, 30, 40 mol% AlN, respectively. The porosities of ATN10 and ATN20 were from 20% to 10% at 1600 °C to 1700 °C while the porosities of ATN30 and ATN40 were almost constant in between 11 and 13%. The addition of AlN effectively decrease the grain size of Al2TiO5 and led to reduce microcrack at the grain boundary.
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Dry film Holographic grating based on computer-generated mask Lithography
(2022-01-01)
Inneam, Chanikan
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Tipawan Khlayboonme, S.
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Kitiwan, Mettaya
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Yindeesuk, Witoon
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Srinuanjan, Keerayoot
This paper presented an alternative technique for fabricating the dry film holographic grating based on a mask generated by computer simulation and experimental results. The mask was generated by a fringe pattern which is created by the mathematical model of two beams interference with various angles. Computer simulation of the fringe pattern was printed on film, i.e., the holographic grating mask. The mask was attached on dry film and then illuminated by UV light, where the lithography technique was applied. According to the lithography technique, the computer-generated holographic grating mask was transferred to dry film. After fabrication, fringe patterns obtained from the grating were observed. Then, the grating period was analyzed and confirmed by Scanning Electron Microscope (SEM). Experimental results show that the method could apply to fabricate the dry film holographic grating.
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Effect of B doping on electrical and thermal properties of SiC bodies fabricated by spark plasma sintering
(2019-01-01)
Taki, Yukina
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Kitiwan, Mettaya
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Katsui, Hirokazu
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Goto, Takashi
B-doped SiC bodies were fabricated by spark plasma sintering at 2373 K, 50 MPa, 300 s in a vacuum and N<inf>2</inf> atmosphere. The relative density of 1 mol% B doped-SiC body sintered in a vacuum and 5 mol% B doped-SiC body sintered in N<inf>2</inf> atmosphere were 97 and 98%, respectively. The electrical conductivity of B-doped SiC bodies sintered in a vacuum with 0.5 mol% B and that with 1 mol% B sintered in N<inf>2</inf> atmosphere showed semi-insulative conduction in the range of 3-510-3 S m-1 at room temperature. The thermal conductivity of B-doped SiC body at 0.5 at% B sintered in a vacuum were 185 W m-1 K-1 while that at 1 at% B sintered in N<inf>2</inf> atmosphere were 177 W m-1 K-1 at room temperature.
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Xps analysis of oxide formed on the surface of co-28cr-6mo-1si alloy oxidized at 550 ºc
(2020-01-01)
Tunthawiroon, Phacharaphon
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Kitiwan, Mettaya
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Wongpromrat, Patthranit
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Chiba, Akihiko
This work investigated the influence of oxidation durations on the formation of oxide on the surface of wrought Co-28Cr-6Mo-1Si alloy. The iso-thermal oxidation was individually performed in air at 550ºC for 4, 12 and 24 h. For comparison, the surface of the non-oxidized Co-28Cr-6Mo-1Si alloy was concurrently examined. The chemical compositions of the non-oxidized and oxidized alloys were principally analyzed via X-ray photoelectron spectroscopy (XPS). The XPS results revealed that the surface of the non-oxidized alloy enriched in Cr-oxide. After oxidation treatment, the Co-oxide, existing as Co2+ state was observed coexisting with two Cr-oxide states, Cr3+ and Cr4+. The low concentrations of Mo6+ were also observed on the oxidized alloy surface. With the increase in oxidation durations, the Co-oxide was suppressed by Cr-oxide. The XPS depth profile analysis indicated that the thickness of the oxide film increased with increasing the oxidation duration.
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Investigation of Contact Angles of SnAgCu Solder Paste Mixed with Graphene Oxide Using Digital Holography Technique
(2021-01-20)
Jongjinakool, Kavisra
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Prakobsang, Tawipon
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Plaipichit, Suwan
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Kanlayasiri, Kannachai
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Kitiwan, Mettaya
Since lead is a pollutant to the environment, therefore lead-free solder paste compounds have been interested in many research teams. The objective of this research is the investigation properties of solder paste with graphene oxide and reduced graphene oxide. In our experimental method the solder pastes of SnAgCu mixed with graphene oxide with bad electrical conductivity at different concentration by weight of 0.00%, 0.05%, 0.1% and 0.2% respectively. Subsequently, the shape changes of the compounds have been investigated by using digital in-line holography using laser diode wavelength 635 nm as the light source. The solder paste compounds were melted at 250 ± 5 °C and were recorded for every 5 seconds. Then, the contact angles of the melted solder paste compound have been determined using their digital holographic reconstructed images.
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Effect of expanded perlite on physical and mechanical properties of cement mortar
(2021-09-15)
Patthanavarit, Jira
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Kitiwan, Mettaya
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Keawprak, Nittaya
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Tunthawiroon, Phacharaphon
This study presents an investigation of the physical and mechanical properties of the cement mortar containing expanded perlite as a filler material. The effects of perlite replacement contents and compressive molding force on bulk density, water absorption, and flexural strength were observed. In the mixture of mortar, the content of sand was replaced with perlite ranging from 0 to 15% by weight. The specimen was pressed under the uniaxial force varied from 20 to 40 kN then de-molded and cured in the humidity for 28 days. With the increase in perlite content from 0 to 15 wt%, the bulk density decreased from 2118 kg/m3 to 1586 kg/m3 while the water absorption increased from 7.4% to18.7%. All composites showed a low thermal conductivity in the range of 0.10-0.27 W/m K. The specimen without perlite had a flexural strength in the range of 10.7-14.2 MPa, while that of sample containing perlite was 7.8-12.5 MPa. The cement mortar composite containing 10 wt% expanded perlite and molding at 40 kN showed the highest flexural strength of 12.50±1.36 MPa while the bulk density and water absorption were 1773 kg/m3 and 1.40 %, respectively. The results of this research can be used as a guideline for further development in building materials such as lightweight roof tile, lightweight brick, and ceiling tile.
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The Addition of Fluoride to the Eggshell-derived Hydroxyapatite: A Preliminary Study
(2021-01-01)
Uthayaphamornwat, Vilasinee
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Suksap, Arissara
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Khantachawana, Anak
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Kitiwan, Mettaya
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Srirussamee, Kasama
Dental caries are one of the major oral health problems, which could be mitigated by addressing the dental defects. Hydroxyapatite (HA) is commonly used for tooth and bone replacement due toits similar properties as the native hard tissues. Natural sources with abundant availability, such as eggshells, could be used to synthesize HA. Moreover, with the presence of fluorine in HA, it was suggested that the performance of this material could be enhanced in terms of material stability and anti-caries properties. This preliminary study aims to compare two methods used to produce fluoride-added HA from eggshells, which are pH cycling and wet precipitation methods. The molecular structure, crystal structure, particle appearance and chemical compositions of the obtained samples were characterized. The results suggested that pH cycling has provided samples with higher fluorine content, more crystalline structure and less CO3than those obtained from wet precipitation method. Therefore, pH cycling method appears to be more suitable for further processing and characterization of the fluoride-added HA samples derived from eggshells.
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Characterization of Fluoride-added Hydroxyapatite Derived from Eggshells for Dental Application
(2023-01-01)
Uthayaphamornwat, Vilasinee
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Khantachawana, Anak
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Kitiwan, Mettaya
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Srirussamee, Kasama
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Tunthawiroon, Phacharaphon
Hydroxyapatite (HA) is one of the potential biomaterials used for treating dental defects. It can be incorporated with fluoride to enhance its anti-caries properties, though other properties could be dependent on processing technique. Hence, this study aims to characterize the influence of sintering on the properties of fluoride-added HA derived from eggshells. FTIR and XRD techniques are used to characterize the chemical and crystal structures of the samples, whilst dissolution test is carried out to characterize material degradation in the acidic environment. The results show that sintering increased the crystallinity in both HA and fluoride-add HA (F-HA) samples, which corresponds with the enhanced stability during the dissolution test. Moreover, it is also found that the addition of fluoride could further stabilize the material structure, though the impurities found in all the samples still need to be minimized. These findings suggest that sintering and fluoride addition could potentially enhance anti-caries properties of eggshell-derived HA, which could be beneficial for dental application in future subject to further process optimization and analysis.

Kitiwan, Mettaya

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