• Food Science of Animal Resources
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• v.35 no.4
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• pp.459-465
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• 2015

Bovine milk provides essential nutrients, including immunologically important molecules, as the primary source of nutrition to newborns. Recent studies showed that RNAs from bovine milk contain immune-related microRNAs (miRNA) that regulate various immune systems. To evaluate the biological and immunological activity of miRNAs from milk products, isolation methods need to be established. Six methods for extracting total RNAs from bovine colostrums were adopted to evaluate the isolating efficiency and expression of miRNAs. Total RNA from milk was presented in formulation of small RNAs, rather than ribosomal RNAs. Column-combined phenol isolating methods showed high recovery of total RNAs, especially the commercial columns for biofluid samples, which demonstrated outstanding efficiency for recovering miRNAs. We also evaluated the quantity of five immune-related miRNAs (miR-93, miR-106a, miR-155, miR-181a, miR-451) in milk processed by temperature treatments including low temperature for long time (LTLT, 63℃ for 30 min)-, high temperature for short time (HTST, 75℃ for 15 s)-, and ultra heat treatment (UHT, 120-130℃ for 0.5-4 s). All targeted miRNAs had significantly reduced levels in processed milks compared to colostrum and raw mature milk. Interestingly, the amount of immune-related miRNAs from HTST milk was more resistant than those of LTLT and UHT milks. Our present study examined defined methods of RNA isolation and quantification of immune-specific miRNAs from small volumes of milk for use in further analysis.

• Journal of Institute of Control, Robotics and Systems
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• v.13 no.11
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• pp.1060-1066
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• 2007

When a high-energy ultrasound propagates through a solid body that contains a crack or a delamination, the two faces of the defect do not ordinarily vibrate in unison, and dissipative phenomena such as friction, rubbing and clapping between the faces will convert some of the vibrational energy to heat. By combining this heating effect with infrared imaging, one can detect a subsurface defect in material efficiently. In this paper a detection of the welding defect of thin SUS 304 plates using the UIR (ultrasonic infrared imaging) technology is described. A low frequency (20kHz) ultrasonic transducer was used to infuse the welded thin SUS 304 plates with a short pulse of sound for 280ms. The ultrasonic source has a maximum power of 2kW. The surface temperature of the area under inspection is imaged by a thermal infrared camera that is coupled to a fast frame grabber in a computer. The hot spots, which are a small area around the defect tip and heated up highly, are observed. From the sequence of the thermosonic images, the location of defective or inhomogeneous regions in the welded thin SUS 304 plates can be detected easily.

• KIEAE Journal
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• v.15 no.1
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• pp.103-109
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• 2015

Recently, the usage of renewable energy system has been recommended because of the energy saving and depletion of fossil fuel. Especially, ground source heat pump system(GSHP) has a high efficiency by using annual stable ground temperature. Also, wood pellet is low cost and a high calorific value compared to fossil fuel. However, only small number of farms have applied renewable energy system to horticultural facility because of a high initial costs and uncertainty of its cost efficiency. In this study, in order to analyze the feasibility for the horticulture, TRNSYS simulation based on the standard horticultural facility was conducted in different weather and covering material conditions. Then, comparative feasibility analysis of each energy supplying system was conducted. As a result, we have found out that a high initial cost of renewable energy system was recovered by the economics of the energy cost. Due to the energy cost reduction, the payback periods were 10-11 years in the case of GSHP and 4-6 years in the case of wood pellet boiler.

• The KSFM Journal of Fluid Machinery
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• v.18 no.4
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• pp.5-12
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• 2015

Several working fluids for Organic Rankine Cycle(ORC) were recommended by many researchers. However, the recommended optimal working fluids were not exactly same because the operating conditions of ORC and application were different. The major parameter to select the working fluid for ORC was the temperature of available thermal energy. In this study, low-grade thermal energy was used for the heat source for ORC and the appropriate working fluids were searched among 26 candidate working fluids. The requirements to be a working fluid for ORC were reviewed and the cycle analysis for simple cycle was conducted with $75^{\circ}C$ and $35^{\circ}C$ at the turbine inlet and exit, respectively. R600, R601, toluene were best candidates if the system could work without leaking the working fluid. Next, R236ea, R245ca, R245fa were recommended because they are not inflammable working fluids as well as better efficiency.

• Resources Recycling
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• v.5 no.4
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• pp.17-24
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• 1996

The computer simulation model was established to verify the applicability of smelting reduction concept to treatment of industrial wastes which becomes issue on the enviromental and recycling view point. Computer simulation model provides as following results. The increase of post combustion ratio(PCR) and heat transfer efficiency of PC energy(HTE) is effective ways to save energy. But, in order to increase PCR, recovery efficiency of post combustion energy(HTE) have to be higher than 85% HTE considering refractory life and saving energy together. Coke is most useful fuel source because it shows lowest dependence of PCR and low hydrogen content. The quality of hot metal of current process would be expected to the similar level with that of blast furnace. The utilization of scrap and Al dross can be also possible to maximize the advantages of current process which is high temperature and chemical dilution with hot metal and slag. In case of scrap, energy consumption was slightly increases because of heating up energy of scrap. Consquently, current process concept provides the possibility of intergrating recycles of industrial wastes materials such as EAF slag, coke oven dust, life terminated acidic refractory, aluminium dross and scrap by smelting reduction process.

• Journal of Energy Engineering
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• v.10 no.3
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• pp.195-205
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• 2001

A great deal of energy is necessary with emission of lots of wastewater in dyeing and finishing process, but heat recovery from wastewater is not introduced since is technology is not developed yet. In order to obtain the method utilizing hot water produced by heat source, that is, dyeing wastewater it was investigated the characteristics of dyeing and finishing process and energy basic unit. Energy basic unit of polyester/cotton (T/C), polyester/rayon (T/R) and polyester dyeing process are higher than that of the other process. The average quantity of wastewater for each dyeing company is 20,470 ton/month, the average temperature of wastewater is about 41$^{\circ}C$. Because the SS solution of wastewater in polyester dyeing process is lower than that of the other process, the effect of corrosion in heat recovery system is low. Since the energy price for 1000 kcal produced by vapor compression heat pump is presumed to be 22.50 won, it is found to be very economic heat recovery system, and its payback is 2.09 years for the factory with LNG boiler.

• Journal of the Korean Institute of Gas
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• v.19 no.4
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• pp.41-48
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• 2015

The performance characteristics of a scroll expander is the most important variable for the performance of organic Rankine cycle system. In this paper, the performance characteristics of a scroll expander was identified using 1kW class organic Rankine cycle system with various operating conditions. The ORC system is composed of an evaporator, a scroll expander, a condenser and a working fluid feed pump that uses R245fa as working fluid. The hot water temperature was controlled from $80^{\circ}C$ to $115^{\circ}C$ by the 50kW-class electric water-heater. The maximum isentropic efficiency of the scroll expander was measured about 77%, and the shaft power was measured from 0.5 kW to 1.8 kW according to heat source temperatures.

• Journal of Korea Society of Industrial Information Systems
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• v.24 no.5
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• pp.9-16
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• 2019

In today's global energy market, the importance of green energy is emerging. Hydrogen energy is the future clean energy source and one of the pollution-free energy sources. In particular, the fuel cell method using hydrogen enhances the flexibility of renewable energy and enables energy storage and conversion for a long time. Therefore, it is considered to be a solution that can solve environmental problems caused by the use of fossil resources and energy problems caused by exhaustion of resources simultaneously. The purpose of this study is to efficiently produce hydrogen using plasma, and to study the optimization of DME reforming by checking the reforming reaction and yield according to temperature. The research method uses a 2.45 GHz electromagnetic plasma torch to produce hydrogen by reforming DME(Di Methyl Ether), a clean fuel. Gasification analysis was performed under low temperature conditions ($T3=1100^{\circ}C$), low temperature peroxygen conditions ($T3=1100^{\circ}C$), and high temperature conditions ($T3=1376^{\circ}C$). The low temperature gasification analysis showed that methane is generated due to unstable reforming reaction near $1100^{\circ}C$. The low temperature peroxygen gasification analysis showed less hydrogen but more carbon dioxide than the low temperature gasification analysis. Gasification analysis at high temperature indicated that methane was generated from about $1150^{\circ}C$, but it was not generated above $1200^{\circ}C$. In conclusion, the higher the temperature during the reforming reaction, the higher the proportion of hydrogen, but the higher the proportion of CO. However, it was confirmed that the problem of heat loss and reforming occurred due to the structural problem of the gasifier. In future developments, there is a need to reduce incomplete combustion by improving gasifiers to obtain high yields of hydrogen and to reduce the generation of gases such as carbon monoxide and methane. The optimization plan to produce hydrogen by steam plasma reforming of DME proposed in this study is expected to make a meaningful contribution to producing eco-friendly and renewable energy in the future.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.15 no.2
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• pp.666-671
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• 2014

Using positive temperature coefficient (PTC) heater as supplementary heating for diesel engine vehicles with low heat source is a good method to enhance the heating performance during cold start. In this study, the PTC elements were made by using screen printing process for forming ohmic contact layer, and prototype of PTC heater was designed and made for a diesel engine vehicle. In process of designing the PTC heater, the thermal flow analysis of PTC element modules was conducted for verifying the effect of the shapes of contact surface between each of the components (cooling fin, insulator, ceramic element). We also investigated the performance characteristic (heating capacity, energy efficiency, pressure drop) of the PTC heater through the experiments. Therefore, the experimental results indicated that prototype of PTC heater had satisfactory performance. This study will be basis for improving the manufacturing process and increasing the performance of the PTC element and heater.

• Korean Journal of Food Science and Technology
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• v.31 no.3
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• pp.638-643
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• 1999

In this study we prepared 5 types of nutritional beverage base samples containing various ratios of soy protein isolate (SPI) and sodium caseinate as protein source. The rheological properties of each sample were measured and the results were as followes; Samples changed their rheological properties with the ratio of SPI. Samples represented newtonian property with low ratio of SPI, pseudoplastic property with the increment of SPI, and bingham pseudoplastic property with higher increment of SPI (80% as protein source). In this result we conjectured that the more was the SPI, the more was the formation of progel during heat treatment, which could be the reason of the rheological changes. In the test of the relationship between temperature and apparent viscosity, apparent viscosity of samples decreased along with the increment of temperature. In observing the relationship between time and apparent viscosity, we found sample, containing high ratio of SPI (80%), represented thixotropic property clearly with the hysteresis loop.