Browsing by Author "Udomsak Kitthawee"

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    A facile fynthesis of ZnS nanostructures via liquid-solid reactions
    (Trans Tech Publications Ltd, 2014) Weerachon Phoohinkong; Thitinat Sukonket; Udomsak Kitthawee
    Zinc sulfide (ZnS) nanostructures are important materials for many technologies such as sensors, infrared windows, transistors, LED displays, and solar cells. However, many methods of synthesizing ZnS nanostructures are complex and require expensive equipment. In this study, a liquid-solid chemical reaction without surfactant was used to synthesize ZnS at room temperature. In addition, commercial grade zinc oxide (ZnO) particles were used as a precursor. The effect of the addition of acids and inorganic salts were investigated. The products were characterized by field emission scanning electron microscopy (FESEM) coupled with energy-dispersive X-ray spectroscopy (EDX), and transmission electron microscopy (TEM). The results show that the nanoparticles of ZnS were obtained in hydrochloric acid and acetic acid addition. The diameters were in the range of 10 to 20 nm and 50 to 100 nm, respectively. In the case of a sodium chloride salt addition, a ZnS structure was obtained with a particle size of approximately 5 nm and a flake-like morphology. © (2014) Trans Tech Publications, Switzerland.
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    Effect of rice husk ash to mechanical properties of clay bricks
    (2013) Sutas Janbuala; Udomsak Kitthawee; Mana Aermbua; Pitak Laoratanakul
    This research explored the effect of rice husk ash on the mechanical properties of clay bricks, for example, strength, density, and water absorption. Rice husk ash, varying 0 to 5% by weight, was added. The results showed that porosity increased when adding rice husk. Adding 3% rice husk ash by weight showed the best mechanical brick properties, with 13.50 MPa of compressive strength, 1.69 g/cm3 of density, and 11.50% of water absorption. © (2013) Trans Tech Publications, Switzerland.
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    Effect of sludge from water treatment plant on properties of pottery
    (Trans Tech Publications Ltd, 2014) Sutas Janbuala; Wittawat Ratanathavorn; Mana Aermbua; Arpapan Satayavibul; Udomsak Kitthawee
    This research aims to study the effect of sludge from water treatment plants on the properties of pottery such as density, compressive strength, water absorption, and porosity.The composition of sludge from water treatment plants added to the clay varies, at percentages of 0%, 10%, 20%, 30%, 40%, and 50%, controlled by weight. The results showed that the composition of 10% by weight of sludge from the water treatment plant yields the ultimate pottery properties, with 12.63 MPa of compressive strength, 1.85 g/cm3 of density, 14.24% of water absorption, and 26.34% of porosity. © (2014) Trans Tech Publications, Switzerland.
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    Firmness properties of mangoes
    (2007) Bundit Jarimopas; Udomsak Kitthawee; B. Jarimopas; Department of Agricultural Engineering, Faculty of Engineering, Kamphaengsaen Kasetsart University, Kamphaenagsaen, Nakohn Pathom, Thailand; email: jarimopas@yahoo.com
    The purpose of this research was to determine the firmness of mango fruit at different stages of maturity. Immature, mature, and over mature fruit from two Thai mango cultivars (Nam Dokmai and Chok Anan) were subjected to two firmness measuring techniques: a slow compression technique using the Universal Testing Machine and a high-speed impact sensing technique using the low-mass impact tester. The firmness of a mango as determined by the compression test was expressed by the slope of the force-deformation graph, while firmness values derived from the impact test were defined by the ratio between maximum acceleration and the corresponding time (the firmness index). A very good correlation between the two indicators was obtained. Each firmness indicator of the two cultivars remained relatively unchanged from the immature through to the fully mature stage, although firmness rapidly decreased as the fruit ripened. The Chok Anan cultivar was firmer than the Nam Dokmai type throughout the development period. The impact method was able to determine mango firmness rapidly, accurately, and non-destructively.
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    Low-cost and fast production of nano-silica from rice husk ash
    (Trans Tech Publications Ltd, 2014) Weerachon Phoohinkong; Udomsak Kitthawee
    Silica with nanostructure are the high quality silica that are used in many industry areas. The applications of silica nanostructure frequently depend on physical properties such as morphology and size of structure. Rice husk ash is the waste from biomass power plants and is a high quality, raw material as a silica source. The conventional methods for synthesis of nano-silica from rice husk ash are energy consumption or time consumption. The objective of this work was to investigate the synthesized of nano-silica from rice husk ash via sodium silicate solution. Nano-silica particles were obtained via alkaline extraction and a fast acid precipitation method at room temperature by adding inorganic salts and without surfactant or template. The flow synthesis was investigated at ambient temperature, varying the concentration of hydrochloric acid, sodium chloride, and flow-rate while fixing the concentration of sodium silicate. The samples were characterized by field emission scanning electron microscopy (FESEM), transmission electron microscopy (TEM), and X-ray diffraction (XRD). The results revealed that the sodium chloride is significantly inorganic salt for generated nano-silica, with uniform spherical morphology (80-150 nm), without curing or aging time. In the flow synthesis method, the silica nanoparticles, of diameter around 10 nm and aggregate particles of around 50 to 200 nm, were obtained. This method may be applicable to control different grade of silica and can easily scaling up of silica production for different industries. © (2014) Trans Tech Publications, Switzerland.
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    Preparation and characterization of dextran-modified ZnO and Cu-doped ZnO nanohybrid material for enhanced antimicrobial delivery and activity
    (Elsevier Ltd, 2025) Tita Foophow; Pipat Lertkowit; Udomsak Kitthawee; Weerachon Phoohinkong; W. Phoohinkong; Faculty of Science and Technology, Suan Dusit University, Bangkok, 10300, Thailand; email: weerachon_pho@dusit.ac.th
    Zinc oxide (ZnO) nanoparticles are widely used in various applications, particularly in antimicrobial products. Efforts to enhance their performance and efficacy, including copper (Cu) doping and incorporating natural polymers. In this study, dextran-modified ZnO and Cu-doped ZnO nanohybrids were synthesized and characterized using exodextran isolated from Leuconostoc mesenteroides TISTR 473. Characterization results showed that dextran binds to the surface of ZnO particles through C[sbnd]O_Zn and C-OH_O interactions, particularly at oxygen vacancy sites. The incorporation of dextran improved the antibacterial efficacy of ZnO and Cu-doped ZnO nanoparticles against bacteria related to fruit and vegetable spoilage, including gram-positive Bacillus altitudinis and gram-negative Achromobacter mucicolens. These findings highlight the potential of dextran-modified ZnO nanomaterials in enhancing antimicrobial activity and biocompatibility for biomedical applications, as well as their use in food packaging to extend shelf life. © 2024 Elsevier Ltd