• Korean Journal of Air-Conditioning and Refrigeration Engineering
• /
• v.22 no.7
• /
• pp.492-507
• /
• 2010

This article reviews the papers published in the Korean Journal of Air-Conditioning and Refrigeration Engineering during 2009. It is intended to understand the status of current research in the areas of heating, cooling, ventilation, sanitation, and indoor environments of buildings and plant facilities. Conclusions are as follows. (1) Research trends of thermal and fluid engineering have been surveyed as groups of general thermal and fluid flow, fluid machinery and piping, and new and renewable energy. Various topics were covered in the field of general thermal and fluid flow such as an expander, a capillary tube, the flow of micro-channel water blocks, the friction and anti-wear characteristics of nano oils with mixtures of refrigerant oils, etc. Research issues mainly focused on the design of micro-pumps and fans, the heat resistance reliability of axial smoke exhaust fans, and hood systems in the field of fluid machinery and piping. Studies on ground water sources were executed concerning two well type geothermal heat pumps and multi-heat pumps in the field of new and renewable energy. (2) Research works on heat transfer area have been reviewed in the categories of heat transfer characteristics and industrial heat exchangers. Researches on heat transfer characteristics included the heat transfer in thermoelectric cooling systems, refrigerants, evaporators, dryers, desiccant rotors. In the area of industrial heat exchangers, researches on high temperature ceramic heat exchangers, plate heat exchangers, frosting on fins of heat exchangers were performed. (3) In the field of refrigeration, papers were presented on alternative refrigerants, system improvements, and the utilization of various energy sources. Refrigeration systems with alternative refrigerants such as hydrocarbons, mixed refrigerants, and $CO_2$ were studied. Efforts to improve the performance of refrigeration systems were made applying various ideas of suction line heat exchangers, subcooling bypass lines and gas injection systems. Studies on heat pump systems using unutilized energy sources such as river water, underground water, and waste heat were also reported. (4) Research trend in the field of mechanical building facilities has been found to be mainly focused on field applications rather than performance improvements. In the area of cogeneration systems, papers on energy and economic analysis, LCC analysis and cost estimating were reported. Studies on ventilation and heat recovery systems introduced the effect on fire and smoke control, and energy reduction. Papers on district cooling and heating systems dealt with design capacity evaluation, application plan and field application. Also, the maintenance and management of building service equipments were presented for HVAC systems. (5) In the field of architectural environment, various studies were carried to improve indoor air quality and to analyze the heat load characteristics of buildings by energy simulation. These studies helped to understand the physics related to building load characteristics and to improve the quality of architectural environment where human beings reside in.

• Food Science and Preservation
• /
• v.20 no.4
• /
• pp.451-458
• /
• 2013

The purpose of this research is to distinguish the quantitative determination of phytochemicals in various agricultural products and to optimize an HPLC method for the determination of lycopene, lutein, ${\alpha}$-carotene, ${\beta}$-carotene, and cryptoxanthin. Among the different conditions studied, the most suitable ones for our samples were the extraction with hexane/acetone/ethanol (50:25:25, v/v/v), dissolution of the dry extract in tetrahydrofuran/acetonitrile/methanol (15:30:55, v/v/v), injection on a $C_{18}$ column with methanol/acetonitrile (90:10, v/v) + triethylamine $9{\mu}M$ as mobile phase, and ${\lambda}_{detection}$=475 nm. The mean percent recovery for the HPLC method were $120.7{\pm}4.1%$ (lycopene), $89.2{\pm}3.5%$ (lutein), $91.2{\pm}2.9%$ (${\alpha}$-carotene), $99.1{\pm}4.4%$ (${\beta}$-carotene), and $100.0{\pm}5.3%$ (cryptoxanthin). The contents of lutein in the agricultural products were spinach, kiwi, tomato, blueberry, melon, respectively. However, the lycopene contents were the highest in the Black tomato ($56.66{\pm}7.48mg/kg$) and Jangseong tomato ($50.28{\pm}5.42mg/kg$). The concentration of ${\beta}$-carotene in all of the agricultural products ranged from 0.07 mg/kg to 65.03 mg/kg. The quercetin content of the agricultural products increased in the order of blueberry (986.57~1,054.06 mg/100 g), kiwi (44.96~55.09 mg/100 g), hallabong (31.92~35.60 mg/100 g), and tomato (26.38~34.94 mg/100 g). The highest kaempferol content was found in the blueberry (47.79~76.15 mg/100 g) with results in all of the tested samples varying between 6.54~48.11 mg/100 g. The total polyphenol contents of the various agricultural products increased in the blueberry (213.60~229.96 mg/100 g), spinach (112.50~141.67 mg/100 g) and kiwi (46.49~70.44 mg/100 g). The total flavonoid content was the highest in both blueberry and spinach. Vitamin C content was detected in kiwi > hallabong > tomato > blueberry, respectively. The total anthocyanin contents (TAC) was detected in the Damyang blueberry and the imported blueberry.

• Journal of Korean Society of Environmental Engineers
• /
• v.27 no.6
• /
• pp.590-598
• /
• 2005

An adequate method to identify chromium separation, Cr(III) and Cr(VI), in water samples were studied by using High Performance Liquid Chromatography(HPLC) coupled with Inductively Coupled Plasma Mass Spectometer(ICP-MS) equipped with Dynamic Reaction Cell(DRC). The characteristic distribution of Cr(III) and Cr(VI) in the raw water taken at the six water intake stations in Seoul, was analyzed by the method developed by the authors. The chromium species separated by HPLC was isocratically conducted by using tetrabutylammonium phosphate monobasic(1.0 mM TBAP), ethylenediaminetetraacetic acid(0.6 mM EDTA) and 2% v/v methanol as the mobile phase. 5% v/v methanol was used as flushing solvent. A reactive ammonia($NH_3$) gas was used to eliminate the potential interference of $ArC^+$. Several Parameters such as solvent ratio, pH, flow rate and sample injection volume were optimized for the successful separation and reproducibility. Although it has been reported thai the separation sensitivity of Cr(III) is superior to that of Cr(VI), the authors observed Cr(VI) was more sensitive than Cr(III) when ammonia($NH_3$) gas was used as the reaction gas. It took less than 3 minutes to analyze chromium species with this method and the estimated detection limits were $0.061\;{\mu}g/L$ for Cr(III) and $0.052\;{\mu}g/L$, for Cr(VI). According to the results from the analysis on chromium species in the raw water of the six intake stations, the concentrations of Cr(III) ranged from 0.048 to $0.064\;{\mu}g/L$(ave. $0.054\;{\mu}g/L$) while that of Cr(VI) ranged from 0.014 to $0.023\;{\mu}g/L$(ave. $0.019\;{\mu}g/L$). Recovery ratio was very high($90.1{\sim}94.1%$). There were two or three times more Cr(III) than Cr(VI) in the raw water.