• Journal of the Korean Wood Science and Technology
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• v.47 no.2
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• pp.129-144
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• 2019

This study aimed at developing an accelerated collection method that reduces measurement and collection time by improving and complementing the desiccator method, which is mainly used for quality control in wood-based panels and furniture production sites. First, this study measured the formaldehyde emissions from the wood-based panels by grade using the desiccator method. Further, this study compared the desiccator method with the developed process and analyzed the correlation in optimal temperature, time, and exposed area. The results showed that the developed process resulted in relatively similar outcomes in comparison to the desiccator method when the temperature was $100^{\circ}C$, the time was 1 h, and two specimens were used, at which the correlation was high. To verify the developed process, this study commissioned Korea Conformity Laboratories with the standardized temperature, time, and the number of specimens to compare them with the specimen that was not used in the actual test. As a result, the correlation to the desiccator method was shown to be very high. However, the formaldehyde emission measured by the accelerated collection process was mostly higher than that measured by the desiccator method. The formaldehyde emission grades from several specimens were one level higher. However, from the perspectives of quality control, it was determined that the accelerated collection method developed in this study could be sufficiently used.

• Journal of Life Science
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• v.15 no.5 s.72
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• pp.840-846
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• 2005

This study was carried out to investigate the effect of electron beam irradiation and cooking temperature on physico-chemical characteristics and lipid oxidation of beef. A total of six beef carcasses ($280\∼300 kg$) that were quality grade $1^{+}$(marbling score No.7, meat color No.4, maturity No.1, texture No.1) was purchased at the commercial slaughter house. The carcasses were transported and washed using high pressure water, and pasteulized with $ 50\% $ ethyl alcohol in the laboratory. After the carcasses were deboned and trimmed, loin and round were taken out to make steak (1.5cm thickness) or ground beef respectively. Samples were wrap or vacuum packaged and irradiated with 0, 3, 4.5, 6 and 7.5 kGy using electron-beam accelerator at Samsung Heavy Industries Ltd. Co. (in Taejun). Irradiated samples were cooked with different methods(electronic pan and gas oven) and temperatures ($ 60^{\circ}C, 70^{\circ}C and 80^{\circ}C$) and used to measure fatty acid composition, TBARS, cholesterol oxide products and panel test scores. The content of saturated fatty acids increased by increasing heating temperature in oven boiling steak (OBS) and pan boiling steak (PBS), and there was no difference by electron-beam irradiation. Both irradiated and non-irradiated treatment were high as the heating temperature increased in TBARS by heating temperature in PBS (p < 0.05) and the amount of Malonaldehyde (MA), standard of fat deterioration, was increased in OBS (p < 0.05). Non-irradiated and 3, 6 kGy treatment produced about 2 fold amount of MA at $ 60^{\circ}C $ compared with $ 80^{\circ}C $. In comparison with PBS, OBS produced much amount of MA and a bit different from non-irradiated treatment but did not show no tendency. As irradiation levels and heating temperature increased, the amount of cholesterol oxides products was increased and also pan-heating method, direct heating method, significantly increased the degree of oxidation compared with oven-heating method, indirect heating method (p < 0.05).

• Journal of Korean Society of Forest Science
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• v.103 no.2
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• pp.159-164
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• 2014

The objective of this study was to establish an open-field experimental warming treatment and precipitation manipulation system to simulate climate change impact for Pinus densiflora seedlings based on a climate change scenario in Korea. Two-year-old seedlings were planted in a nursery in April, 2013. The air temperature of warmed plots (W) was set to increase by $3.0^{\circ}C$ compared to control plots (C) using infrared lamps from May, 2013. The three precipitation manipulation consisted of precipitation decrease using transparent panel (-30%; $P^-$), precipitation increase using pump and drip-irrigation (+30%; $P^+$) and precipitation control (0%; $P^0$). Initially, the air temperature was $2.2^{\circ}C$ higher in warmed plots than in control plots and later air temperature was maintained close to the target temperature of $3.0^{\circ}C$. The average soil temperature was $3.1^{\circ}C$ higher in warmed plots than in control plots. Also the average soil moisture content after the precipitation manipulation increased by 13.9% in $P^+W$ and decreased by 10.0% in $P^-W$ compared to $P^0W$, and increased by 23.7% in $P^+C$ and decreased by 7.6% in $P^-C$ compared to $P^0C$. It was confirmed that the open-field experimental warming and precipitation manipulation system was properly designed and operating.

• Journal of Bio-Environment Control
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• v.26 no.4
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• pp.353-360
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• 2017

In this study, the design and performance test of the air to water heat pump capable of producing hot water for greenhouse heating by using the surplus solar heat inside the greenhouse and the air heat outside greenhouse as the selective heat source were conducted. The heat storage operations using the surplus solar heat and the outside air heat were designed to be switched according to the setting temperature of the greenhouse in consideration of the optimum temperature range of the crop. In the developed system, it was possible to automatically control the switching of heat storage operation, heating and ventilation by setting 12 reference temperatures on the control panel. In the selective heat storage operation with the surplus solar heat and outside air heat, the temperature of thermal storage tank was controlled variably from $35^{\circ}C$ to $52^{\circ}C$ according to the heat storage rate and heating load. The heat storage operation times using the surplus solar heat and outside air heat were 23.1% and 30.7% of the experimental time respectively and the heat pump pause time was 46.2%. COP(coefficient of performance) of the heat pump of the heat storage operation using the surplus solar heat and outside air heat were 3.83 and 2.77 respectively and was 3.24 for whole selective heat storage operation. For the comparative experiment, the heat storage operation using the outside air heat only was performed under the condition that the temperature of the thermal storage tank was controlled constantly from 50 to $52^{\circ}C$, and COP was analyzed to be 2.33. As a result, it was confirmed that the COP of the heat storage operation using the surplus solar heat and outside air heat as selective heat source and the variable temperature control of the thermal storage tank was 39% higher than that of the general heat storage operation using the outside air heat only and the constant temperature control of the thermal storage tank.

• Proceedings of the Korea Institute of Fire Science and Engineering Conference
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• 2008.11a
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• pp.479-483
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• 2008

There are no International Standards or Criteria pertaining to fires inside tunnels at the moment, but there are some fire-related regulations in some advanced countries such as Germany and the Netherlands where some fire-related studies have been expedited. Germany has established regulations related to the safety of structures by stipulating Fire Curves of RABT and EBA Tunnels. Also, the Netherlands has established the resistance capacity of structures by stipulating RWS curve so that they can prevent the adjacent area from being damaged due to a tunnel collapse. Hydrocarbon Fire Curve is the standard assessing the behaviour of a structure in a serious fire, by increasing the heating speed and the maximum temperature of ISO 834 Curve, while MHC Fire Curve, which was established in France, realizes more serious fire conditions. In this study, we aimed to develop the basis of full-sized experiments, with which you can assess the fire-resisting capacity against the fire strength of concrete PC panel lining, through the realization of various tunnel fire curves as mentioned above, by developing the heating furnace suitable for the requirements of Fire-Resisting Standards, with which you can assess the fire damage of tunnel concrete lining. We have developed various conditions of the heating furnace and the method to install a thermo couple within the furnace based on EFNARC and KS F2257-1. We have also conducted a calibrating experiment in order to secure its reliability.

• Proceedings of the Korean Vacuum Society Conference
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• 2016.02a
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• pp.196.1-196.1
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• 2016

TCO(Transparent Conducting Oxide) on flat glass is used in thin-film photovoltaic cell, flat-panel display. Nowadays, Corning(R) Willow Glass(R), known as flexible substrate, has attracted much attention due to its many advantages such as reliable roll-to-roll glass processing, high-quality flexible electronic devices, high temperature process. Also, it can be an alternative to flexible polymer substrates which have their poor stability and degradation of electrical and optical qualities. For application on willow glass, the flexibility, electrical, optical properties can be greatly influenced by the TCO thin film thickness due to the inherent characterization of thin film in nanoscale. It can be expected that while thick TCO layer causes poor transparency, its sheet resistance become low. Also, rarely reports were focusing on the influence of flexible properties by varying TCO thickness on flexible glass. Therefore, it is very important to optimize TCO thickness on flexible Willow glass. In this study, Ti-ZnO thin films, with different thickness varied from 0 nm to 50 nm, were deposited on the flexible willow glass by atomic layer deposition (ALD). The flexible, electrical and optical properties were investigated, respectively. Also, these properties of Ti-doped ZnO thin films were compared with un-doped ZnO thin film. Based on the results, when Ti-ZnO thin films thickness increased, resistivity decreased and then saturated; transmittance decreased. The Figure of Merit (FoM) and flexibility was the highest when Ti-ZnO thickness was 40nm. The flexible, electrical and optical properties of Ti-ZnO thin films were better than ZnO thin film at the same thickness.

• Nuclear Engineering and Technology
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• v.49 no.7
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• pp.1442-1450
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• 2017

In liquid metal fast breeder reactors, postulated failures of the plant protection system may lead to serious unprotected accidental consequences. Unprotected transients are generically categorized as transient overpower accidents and transient under cooling accidents. In both cases, core meltdown may occur and this can lead to a molten fuel coolant interaction (MFCI). The understanding of MFCI phenomena is essential for study of debris coolability and characteristics during post-accident heat removal. Sodium is used as coolant in liquid metal fast breeder reactors. Viewing inside sodium at elevated temperature is impossible because of its opaqueness. In the present study, a methodology to depict MFCI phenomena using a flat panel detector based imaging system (i.e., real time radiography) is brought out using a woods metal-water experimental facility which simulates the $UO_2-Na$ interaction. The developed imaging system can capture attributes of the MFCI process like jet breakup length, jet front velocity, fragmented particle size, and a profile of the debris bed using digital image processing methods like image filtering, segmentation, and edge detection. This paper describes the MFCI process and developed imaging methodology to capture MFCI attributes which are directly related to the safe aspects of a sodium fast reactor.

• Journal of Welding and Joining
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• v.27 no.5
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• pp.74-80
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• 2009

The membrane of the LNG carriers consists of thin strips of INVAR(Fe-36%Ni) steel plates, and the junction between INVAR strips is fabricated by welding. Thousands of the raised edge joints, regularly spaced, are located around all the side of the tank corner near the transverse bulkhead, and TIG welding is manually made on the top of the raised edges. Since the thickness of all the laminated edge plies is extremely thin and the weld position is under a bad accessibility, highly skilled workers are required to perform welding relatively for a long welding time. An alternative scheme for the corner membrane fabrication is proposed in the study to improve the installation workability and thus productivity. The scheme replaces the welded edges with the preformed corrugation ones. A panel strip with regularly-spaced corrugations is installed at the corner instead of the individual flat strip of which edge is vertically raised to be welded with the adjacent strip. In the study, a series of the evaluation on the corrugated edge members was performed to assess the applicability to the real LNG carrier fabrication. Opening displacement at the raised edge was experimentally examined. Elastic stiffness regressed from the displacement was nearly same in both edge types. Edge displacement and local stresses were calculated under hydrostatic pressure and temperature change due to liquefied cargo. Fatigue test was performed on both corrugated and welded edge specimens consisting of two or five plies of invar strips. Fatigue strength of the corrugated specimens was not less than that of the welded specimens.

• Journal of The Korean Society of Agricultural Engineers
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• v.51 no.5
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• pp.25-34
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• 2009

The objective of this study is to evaluate the future potential climate and vegetation canopy change impact on a dam watershed hydrology. A $6,661.5\;km^2$ dam watershed, the part of Han-river basin which has the watershed outlet at Chungju dam was selected. The SWAT model was calibrated and verified using 9 year and another 7 year daily dam inflow data. The Nash-Sutcliffe model efficiency ranged from 0.43 to 0.91. The Canadian Centre for Climate Modelling and Analysis (CCCma) Coupled Global Climate Model3 (CGCM3) data based on Intergovernmental Panel on Climate Change (IPCC) SRES (Special Report Emission Scenarios) B1 scenario was adopted for future climate condition and the data were downscaled by artificial neural network method. The future vegetation canopy condition was predicted by using nonlinear regression between monthly LAI (Leaf Area Index) of each land cover from MODIS satellite image and monthly mean temperature was accomplished. The future watershed mean temperatures of 2100 increased by $2.0^{\circ}C$, and the precipitation increased by 20.4 % based on 2001 data. The vegetation canopy prediction results showed that the 2100 year LAI of deciduous, evergreen and mixed on April increased 57.1 %, 15.5 %, and 62.5% respectively. The 2100 evapotranspiration, dam inflow, soil moisture content and groundwater recharge increased 10.2 %, 38.1 %, 16.6 %, and 118.9 % respectively. The consideration of future vegetation canopy affected up to 3.0%, 1.3%, 4.2%, and 3.6% respectively for each component.

• Journal of the Korean Society of Food Culture
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• v.2 no.2
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• pp.133-147
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• 1987

The sensory quality characteristics of 7 different types of Korean traditional tea products were analyzed. For the standardization of sensory testing condition, the optimum drinking temperature were measured with 50 students, and all the samples tested were found to fall in the range of $60-70^{\circ}C$. The optimum concentrations of tea for drinking were generally met with the amount recommended by the producer. A total of 45 sensory describing terms expressing the taste, odor, and mouthfeel were collected. Using the sensory describing terms as the character notes, flavor profile analysis was made for each tea product with 8 members of trained panel. The differences in quality characteristics of 29 test samples were evaluated and shown in the chart constructed by the quantitative descriptive analysis method.