• Journal of Mechanical Science and Technology
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• v.15 no.2
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• pp.268-276
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• 2001

In order to improve the efficiency of a direct contact heat exchanger for a solar thermal energy system, the working fluid should be dispersed into small and uniform droplets, and stay within a heat exchanger for a long time. Therefore, installation of meshes in a direct contact heat exchanger is suggested in the present study, and the performance of the direct contact heat exchanger with several layers of meshes is experimentally investigated. Diethyl phthalate is used as the working fluid, and the performance of the heat exchanger is tested for several different operating conditions and compared to that of the heat exchanger without meshes. The results of this investigation show that meshes make droplets uniform and small when the flow rate is low. The relationship between the Peclet number and the Nusselt number becomes linear if it is steady. And, the Nusselt number for the direct contact heat exchanger with meshes becomes greater than that without meshes as the Peclet number increases.

• Journal of Korean Ophthalmic Optics Society
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• v.17 no.1
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• pp.1-10
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• 2012

Purpose: Cellulose acetate (CA) was blended with polyethyleneglycol (PEG) having different molecular weight at various mixing conditions to enhance melt-processibility of CA, which might prevent the harmful effect resulted from the introduction of phthalic plasticizer. Methods: To establish optimal plasticizing conditions, CA/PEG blends were examined under various plasticizing conditions: PEG concentration, molecular weight of PEG, and plasticzing temperature. Mechanical properties of the CA/PEG blends, as well as migration and exudation of the PEG, were performed in order to evaluate the efficiency of plasticization. Results: Compared to industrial CA resin plasticized by diethyl phthalate, CA/PEG blends exhibited similar thermal plasticization. It was established that the optimum condition was to blend 30~40 phr PEG with molecular weight 400 at $175{\sim}180^{\circ}C$. CA/PEG blend showed superior glassness, PEG stability, and mechanical properties. Conclusions: CA/PEG blends would be a eco-friendly glasses frame to substitute traditional CA glasses frame prepared phthalate plasticizers.

• Journal of Pharmaceutical Investigation
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• v.40 no.3
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• pp.167-173
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• 2010

Repeated oral administration of hydrochlorothiazide, a loop diuretic, due to transient high blood levels, may cause adverse effects such as gastric disturbance, nausea, high blood sugar, and hyper lipidemia. Transdermal administration could avoid some of these systemic side effects and gastric disorders. We have developed a matrix using ethylene-vinyl acetate (EVA), a heat-processible and flexible material, for transdermal delivery of hydrochlorothiazide. Drug solubility was highest at 40% PEG-400 volume fraction. Drug release increased as concentration increased with a linear relationship between the release rate and the square root of loading dose. Increasing temperature increased drug release from the EVA matrix. The activation energy, measured from the slope of log P versus 1000/T, was 11.9 kcal/mol for a 2.5% loading dose from EVA matrix. Diethyl phthalate had the highest plasticizing effects on the release of hydrochlorothiazide. To increase the skin permeation of hydrochlorothiazide from the EVA matrix, enhancers such as the saturated fatty acids, the unsaturated fatty acids, and the non-ionic surfactants were added to the EVA matrix, and skin permeation was evaluated using a modified Keshary-Chien diffusion cell fitted with intact excised rat skin. Polyoxyethylene 23-lauryl ether showed the highest enhancing effects. In conclusion, transdermal delivery of hydrochlorothiazide could be improved from an EVA matrix containing plasticizer and permeation enhancer.

• Journal of Environmental Science International
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• v.20 no.2
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• pp.231-239
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• 2011

Diethyl phthalate (DEP) and nonylphenol (NP) are widely spread in the natural environment as an endocrine disruption chemicals (EDs). Therefore, in this study, ultrasound (US) and ultraviolet (UVC), including $TiO_2$, as advanced oxidation processes (AOPs) were applied to a DEP and NP contaminated solution. When only the application of US, the optimum frequency for significant DEP degradation and a high rate of hydrogen peroxide ($H_2O_2$) formation was 283 kHz. We know that the main mechanism of DEP degradation is radical reaction and, NP can be affected by both of radical reaction and pyrolysis through only US (sonolysis) process and combined US+UVC (sonophotolysis) process. At combined AOPs (sonophotolysis/sonophotocatalysis) such as US+UVC and US+UVC+$TiO_2$, significant degradation of DEP and NP were observed. Enhancement effect of sonophotolysis and sonophotocatalysis system of DEP and NP were 1.68/1.38 and 0.99/1.17, respectively. From these results, combined sonophotocatalytic process could be more efficient system to obtain a significant DEP and NP degradation.

• Mycobiology
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• v.45 no.3
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• pp.178-183
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• 2017

Diabetes mellitus is a chronic disorder which affects millions of population worldwide. Global estimates published in 2010 reported the world diabetic prevalence as 6.4%, affecting 285 million adults. Foot ulceration and wound infection are major forms of disabilities arising from diabetic diseases. This study was aimed to develop a natural antimicrobial finishing on medical grade textile that meets American Association of Textiles Chemists and Colorists (AATCC) standard. The textile samples were finished with the ethanolic extract of Penicillium amestolkiae elv609, an endophytic fungus isolated from Orthosiphon stamineus Benth (common name: cat's whiskers). Endophyte is defined as microorganism that reside in the living plant tissue, without causing apparent disease symptom to the host. The antimicrobial efficacy of the ethanolic extract of P. minioluteum was tested on clinical pathogens isolated from diabetic wound. The extract exhibited significant inhibitory activity against 4 bacteria and 1 yeast with the minimal inhibitory concentration ranged from 6.25 to 12.5 mg/mL. The results indicate different susceptibility levels of the test microorganism to the ethanolic extract. However, the killing activity of the extract was concentration-dependent. The finished medical textile showed excellent antimicrobial efficacy on AATCC test assays. All the microbial cultures treated with the textile sample displayed a growth reduction of 99.9% on Hoheinstein Challenge Test. The wash durability of the finished textile was found good even after 50 washes with commercial detergent. Besides, the gas chromatography mass spectrometry analysis showed that 6-octadecenoic acid and diethyl phthalate were the main bioactive constituents of the extract. In conclusion, the developed medical textile showed good antimicrobial efficacy on laboratory tests. This work can be extended to in vivo trials for developing healthcare textile products for antimicrobial applications.