• Journal of the Korea Academia-Industrial cooperation Society
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• v.13 no.10
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• pp.4927-4935
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• 2012

Turmeric is a medicinal herb with various pharmacological activities. Curcumin, demethoxycurcumin(DMC) and bisdemethoxycurcumin(BDMC) were extracted from turmeric by dipping and ultrasonic wave method. And extraction efficiency was identified using solid phase extraction(SPE). The extracted sample were simultaneously separated and analyzed from three kinds of commercial $C_{18}$ reversed-phase high performance liquid chromatography using water and acetonitrile as mobile phase with isocratic elution mode. Flow rate 1.0mL/min, injection volume $10{\mu}L$ and column oven temperature $40^{\circ}C$ at 425nm wavelength has been conducted. From the experimental results, the optimum mobile phase composition of water/acetonitrile 50/50vol% using RS tech column. It is evident that the amount of curcuminoids extracted(extraction time 4h) by 100% MeOH was higher than any aqueous MeOH composition. Finally, in 100% water extraction, the amount(mAU${\times}$mim) of curcuminoids extracted by SPE was 14.3 and 24.5 times respectively higher than ultrasonic wave and dipping method. The shown results can be applied as sources for pharmaceuticals and functional material.

• Journal of Advanced Marine Engineering and Technology
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• v.34 no.5
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• pp.638-644
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• 2010

Numerical predictions of a fully developed turbulent flow through a square duct ($30mm{\times}30mm$) with twisted tape inserts and with twisted tape plus interrupted ribs are respectively conducted to investigate regionally averaged heat transfer and flow patterns. A rib height-to-channel hydraulic diameter(e/$D_h$) of 0.067 and a lengthto-hydraulic diameter(L/$D_h$) of 30 are considered at Reynolds number ranging 8,900 to 29,000. The interrupted ribs are axially arranged on the bottom wall. The twisted tape is 0.1 mm thick carbon steel sheet with diameter of 28 mm, length of 900 mm, and 2.5 turns. Each wall of the square channel is composed of isolated aluminum sections. Two heating conditions are investigated for test channels with twisted tape inserts and rib turbulators: (1) electric heat uniformly applied to four side walls of the square duct, and (2) electric heat uniformly applied to two opposite walls of the square channel. The results show that uneven surface heating enhances the heat transfer coefficient over uniform heating conditions, and significant improvements can be achieved with twisted tape inserts plus interrupted ribs.