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1.
Jatuporn Wittayakun Pongtanawat Khemthong Sanchai Prayoonpokarach 《Korean Journal of Chemical Engineering》2008,25(4):861-864
Rice husk silica (RHS) in amorphous phase with 98% purity was prepared from a waste rice husk from rice milling by leaching
with hydrochloric acid and calcination. The RHS was used effectively as a silica source for the synthesis of zeolite Y in
sodium form (NaY). The zeolite in pure phase was obtained from a two-step synthetic route in which the starting gels were
mixed, aged for 24 h at room temperature and crystallized for 24 h at 90 °C. The diameter of single crystal particles from
a scanning electron microscope was approximately 1.0 μm, whereas the average particle diameter from laser diffraction particle
size analyzer was approximately 10 μm because of the agglomeration of small crystals. Longer crystallization time in this
route resulted in a mixed phase containing NaY and zeolite P in sodium form (NaP). In addition, a one-step synthetic route
(no aging) was studied and the product was also a mixed phase zeolite. 相似文献
2.
Pussadee Paensuwan Thanet Laorob Jatuporn Ngoenkam Uthai Wichai Sutatip Pongcharoen 《International journal of molecular sciences》2022,23(22)
Diabetic cataracts are a common complication that can cause blindness among patients with diabetes mellitus. A novel nitro dihydrocapsaicin (NDHC), a capsaicin analog, was constructed to have a non-pungency effect. The objective of this research was to study the effect of NDHC on human lens epithelial (HLE) cells that lost function from hyperglycemia. HLE cells were pretreated with NDHC before an exposure to high glucose (HG) conditions. The results show that NDHC promoted a deacceleration of cellular senescence in HLE cells. This inhibition of cellular senescence was characterized by a delayed cell growth and lower production of reactive oxygen species (ROS) as well as decreased SA-β-galactosidase activity. Additionally, the expression of Sirt1 protein sharply increased, while the expression of p21 and phospho-p38 proteins decreased. These findings provide evidence that NDHC could exert a pharmacologically protective effect by inhibiting the senescence program of lens cells during diabetic cataracts. 相似文献
3.
The evaporation heat transfer coefficient and pressure drop of R-410A flowing through a horizontal aluminium rectangular multiport mini-channel having 3.48 mm hydraulic diameter are experimentally investigated. The test runs are performed at mass flux ranging between 200 and 400 kg/m2 s. The heat fluxes are between 5 and 14.25 kW/m2 and the saturation temperatures range between 10 and 30 °C. The pressure drop across the test section is directly measured by a differential pressure transducer. The effects of the imposed wall heat flux, mass flux, vapour quality, and saturation temperature on the evaporation heat transfer and pressure drop are also discussed. The results from the present experiment are compared with those obtained from the existing correlation. New correlations for the evaporation heat transfer coefficient and pressure drop of R-410A flowing through a multiport mini-channel are proposed for practical applications. 相似文献
4.
Kitirote Wantala Pongtanawat Khemthong Jatuporn Wittayakun Nurak Grisdanurak 《Korean Journal of Chemical Engineering》2011,28(11):2178-2183
0.1 Fe/Ti mole ratio of Fe-TiO2 catalysts were synthesized via solvothermal method and calcined at various temperatures: 300, 400, and 500 °C. The calcined
catalysts were characterized by XRD, N2-adsorption-desorption, UV-DRS, XRF, and Zeta potential and tested for photocatalytic degradation of alachlor under visible
light. The calcined catalysts consisted only of anatase phase. The BET specific surface area decreased with the calcination
temperatures. The doping Fe ion induced a red shift of absorption capacity from UV to the visible region. The Fe-TiO2 calcined at 400 °C showed the highest photocatalytic activity on degradation of alachlor with assistance of 30 mM H2O2 at pH 3 under visible light irradiation. The degradation fitted well with Langmuir-Hinshelwood model that gave adsorption
coefficient and the reaction rate constant of 0.683 L mg−1 and 0.136 mg/L·min, respectively. 相似文献
5.
The electric field responses of two types of weakly nonlinear dielectric composites consisting of elliptic cylindrical inclusions, one with identical shape and the another with distributed shapes, randomly embedded in the linear host media in the dilute limit are investigated. The dielectric property of the inclusions is that the relation between the displacement (D) and electric (E) fields obey the form D = ?E + χ∣E∣βE where β is a nonlinear integer exponent and ? ? χ∣E∣β. By using the decoupling approximation, the effective nonlinear susceptibility (χe) is determined and analyzed for varying the aspect ratios and the shape distribution parameters for the composites with identical and distributed inclusion shapes, respectively. In addition, the exact analytic result of χe for the elliptical composites with distributed inclusion shapes for the case of β = 2 is derived in this article. 相似文献
6.
7.
Jatuporn?WittayakunEmail author Nurak?Grisdanurak Gerald?Kinger Hannelore?Vinek 《Korean Journal of Chemical Engineering》2004,21(5):950-955
Adsorption behavior of NO and CO as well as their reaction was investigated on cobalt supported zeolite beta (Co/BEA) prepared
by solid-state ion exchange (SSIE) and by impregnation (IMP). By temperature programmed desorption (TPD), two NO desorption
peaks at 100 and 260‡C were observed over both SSIE and IMP catalysts with complete desorption after 450‡C. CO desorbed from
SSIE catalyst between 50 and 200‡C. In the same temperature interval negligible CO2 desorption was observed, most likely due to reaction of CO with trace of cobalt oxides. Over IMP catalysts, desorption of
CO2 was found mainly at 500‡C. By comparing CO TPD profiles from physical mixtures of cobalt oxides and HBEA, SSIE catalysts
most likely contained cobalt cations in zeolite exchange position while IMP catalysts had cobalt in oxidic forms. The SSIE
catalysts were active for NO reduction at 400 and 500‡C with a maximum conversion at 500‡C. However, the activity in the presence
of water and oxygen was low. Water might inhibit the reaction by blocking active sites for NO and CO, while oxygen reacted
with CO to form carbon dioxide. The activity of SSIE was better than IMP catalyst. 相似文献
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9.
Nurak?GrisdanurakEmail author Siriluk?Chiarakorn Jatuporn?Wittayakun 《Korean Journal of Chemical Engineering》2003,20(5):950-955
The adsorption of trichloroethylene (TCE), tetrachloroethylene (PCE), and carbon tetrachloride was studied over our synthesized
mesoporous material, MCM-41, from rice husk silica source, abbreviated as RH-MCM-41. More than 99% silica for RH-MCM-41 synthesis
was extracted from rice husk under refluxing in HBr solution and then calcined at 873 K for 4 hours. RH-MCM-41 possessed surface
area around 750-1,100 m2/g with a uniform pore size with an average diameter of 2.95 nm, narrow range of pore distribution and somewhat hexagonal
structure, similar to properties of parent MCM-41. The adsorption of CC14 to RH-MCM-41 was stronger than that of TCE and PCE. The adsorption capacity of RH-MCM-41 for CVOCs (chlorinated volatile
organic compounds) was higher than commercial mordenite and activated carbons. 相似文献
10.
This article concerns the pressure drop caused by using the electrohydrodynamic (EHD) technique during evaporation of pure R-134a inside smooth and micro-fin tubes. The test section is a counter-flow concentric tube-in-tube heat exchanger where R-134a flows inside the inner tube and hot water flows in the annulus. A smooth tube and micro-fin tube having an inner diameter of 8.12 mm and 8.92 mm, respectively, are used as an inner tube. The length of the inner tube is 2.50 m. The outer tube is a smooth copper tube having an inner diameter of 21.2 mm. The electrode, which is a cylindrical stainless steel wire having diameter of 1.47 mm, is placed in the center of the inner tube. The electrical field is established by connecting a DC high voltage power supply of 2.5 kV to the electrode while the inner tube is grounded. Experiments are conducted at saturation temperatures of 10–20°C, mass fluxes of 200–600 kg/m2s, and heat fluxes of 10–20 kW/m2. The experimental results indicate that the application of EHD introduces a small pressure drop penalty. New correlations for the pressure drop are proposed for practical applications. 相似文献