• Journal of the Korean Ceramic Society
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• v.38 no.11
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• pp.1067-1074
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• 2001

Four different composition of autoxidation drying type waterborne coatings (WBC-1, WBC-2, WBC-3, WBC-4) were prepared by the compounding of bentonite (BEN) as a water swellable clay and organometallic soaps as a drier with acrylic binder and coating additives. The solution viscosity, solid content, rheological properties and drying rate of WBCs were investigated. Also the thermal stability, the transmittance and the water-resistance of the films casted by WBCs were measured, and the surface topology of WBC films were investigated by the scanning probe microscopy. As WBC-2, WBC-3 and WBC-4 containing BEN showed the thixotropy with the shear rate, the storage stability of WBC was a excellent. When the driers was mixed in the ratio of Mn/Zn/Ba=1/2/3, the dry ability of WBCs showed maximum as 5.0 sec at 60$\^{C}$. The initial decomposition temperature and the transmittance of WBC films containing BEN increased in range of 32.2∼54.7$\^{C}$ and 5.1∼8.6% than the commercial WBC (MC-21W), respectively. The water resistance of WBC films increased in order of MC-21W

• Journal of Korean Tunnelling and Underground Space Association
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• v.19 no.2
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• pp.231-248
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• 2017

Government plans to construct a double-deck tunnel under a portion of Gyeongbu Expressway that will solve traffic problems and could also be used as a flood storage facility. Divergence tunnels connect the main tunnel to the urban areas and their construction effects on adjacent structures at shallow depth need to be analyzed. This study primarily includes the numerical analysis of construction effects of divergence tunnels on utility tunnels. The utility tunnel was analyzed for three cases of volume loss applied to the divergence tunnel and two cases of the angle between main tunnel and divergence tunnel ($36^{\circ}$ and $45^{\circ}$). The results show that the more the volume loss was applied and the shorter the distance was between utility tunnel and divergence tunnel, the more the utility tunnel was affected in terms of induced displacements, angular displacement and stability. The worst scenario was found out to be the one where the angle between main tunnel and divergence tunnel was $36^{\circ}$ and the distance between divergence tunnel and utility tunnel was 10 m, resulting in the largest displacement and differential settlement at the bottom of the utility tunnel. A relationship between the angular displacement and the distance to diameter ratio was also established.

• Korean Journal of Agricultural Science
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• v.35 no.2
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• pp.137-145
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• 2008

A layer feeding trial was conducted to investigate the effects of high quality corn distiller's dried grains with solubles(DDGS) on laying performance and nutrient metabolizabilities. A total of 216 Hy-line Brown layers, 23-wk of age, were employed in a 10-wk feeding trial consisting of three dietary treatments(0%, 10%, and 20% DDGS), and six replicates per treatment. All experimental diets were prepared as iso-protein(17%) and iso-calorie(2,780 kcal/kg). At the end of the trial, the effect of DDGS on fecal ammonia emission was also estimated. The use of DDGS up to 20% in layer diets did not affect the feed intake, laying rate, egg weight, and feed conversion ratio(P>0.05). The DM metabolizability decreased significantly(P<0.05) by the DDGS supplementation(P<0.05). The NFE metabolizability decreased gradually as the level of DDGS increased(P<0.05). The fecal ammonia emission from DDGS-fed birds tended to decrease as the storage days extended. In conclusion, albeit DDGS has some unfavorable effects on DM and NFE metabolizabilities, it could be included in layer diets up to 20% level without any harmful effects on laying performance.

• Food Science and Preservation
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• v.17 no.6
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• pp.793-799
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• 2010

Kimchi was fermented in permeability-controlled polyethylene containers, in glazed onggi (Korean ethnic earthenware) or glass bottles at $5^{\circ}C$ for 8 weeks. During 4 weeks of storage, kimchi fermented in the permeability-controlled container showed a stable fermentation pattern, in terms of changes in pH and acidity, compared with kimchi fermented in the other containers. With respect to changes in bacterial counts, kimchi fermented in polyethylene containers showed vigorous multiplication of lactic acid bacteria, especially Lactobacillus sp., but slow growth of total aerobic bacteria. The springiness of kimchi fermented in the polyethylene containers was optimal (about 10% more than that of glass bottle-fermented kimchi), and the overall acceptability and hardness of container-fermented kimchi were excellent upon sensory evaluation. The DPPH radical-scavenging activity of kimchi fermented in polyethylene containers was also greater (91%) than that of kimchi fermented in glazed onggi (73%) or glass bottles (63%). The $O_2$ and $CO_2$ permeabilities of the polyethylene containers were higher (458 and $357\;mmol\;h^{-1}\;m^{-2}\;atm^{-1}$, respectively) than were those of the other containers; the permeability ratio was 0.8. Glass bottles showed no permeance. The results indicate that permeability-controlled polyethylene containers may be used for kimchi fermentation.

• Food Science and Preservation
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• v.16 no.5
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• pp.699-704
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• 2009

Commercially produced 'baby leaves' of Brassica campestris var. narinosa (Chinese cabbage) were used in the present study. Baby leaf vegetables were sown on 128 cell plug trays and harvested 30 days after sowing. For mechanical stress experiments, seedlings were thinned to three per cell, selected for uniformity, and watered at the base. Trays were treated with mechanical stress by stroking back and forth 50 times, using a sheet of A4 paper folded to double thickness. Plants were treated between 12:00 and 14:00 daily for 15-20 days. Harvested baby leaf vegetables were packed in MAP salad bags made of P-plus film, $50{\mu}m$ polypropylene (PP) film, and polyethylene terephthalate (PET) boxes. Fresh weight was well-maintained under P-plus and PP film on storage at $8^{\circ}C$. However, loss of fresh weight occurred quickly in PET boxes, and vegetable quality deteriorated rapidly. Stressed leaves were smaller but thicker, with an increased dry weight ratio. We thus suggest that P-plus or PP film is most appropriate packing for marketing of baby leaf vegetables, which should be stored at $8^{\circ}C$. Our data on baby leaf vegetables also make a significant new contribution in that we demonstrate a positive effect of stress touching on baby leaf processability.

• Korean Journal of Food Science and Technology
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• v.31 no.6
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• pp.1604-1612
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• 1999

The study was carried out to investigate the quality of the wet noodle added with the powders of nopal and nopalitos from Opuntia ficus-indica. The wet noodles were prepared to the ratio of 3, 6 and 9% (w/w) of the nopal and the nopalitos based on a flour weight. The initial pasting temperature and final viscosity in an amylograph decreased as the increase of the nopal and the nopalitos powders. A cooked weight and volume decreased with the increase of the nopal and the nopalitos powders, while a cooking loss increased. From the sensory evaluation, the wet noodles included 3% nopalitos and 6% nopal powders were similarly evaluated as the noodle used whole wheat flour. Bacterial counts of wet noodle with the nopal and the nopalitos powders were always lower than those of the control. Bacterial counts of wet noodle slowly increased as the increase of the amount of nopal and the nopalitos powders during storage at $4^{\circ}C\;and\;20^{\circ}C$. The methanol extracts from the nopal showed antimicrobial activities against Escherichia coli, Escherichia coli O157 : H7, Salmonella typhimurium, and Bacillus subtilis, while the extracts from the nopalitos showed antimicrobial activity only against Escherichia coli.

• Korean Journal of Food Science and Technology
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• v.36 no.2
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• pp.321-328
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• 2004

Raw mulberry (Morus spp.) juice was prepared by minimal processing using several filter aids, fining agents, and clarifying enzymes, followed by filtration, centrifugation, and membrane filtration. Control of browning in minimally processed mulberry juices by anti-browning agents, sodium hydrosulfite, L-ascorbic acid, citric acid, and NaCl, was investigated using quantitative measurements of color changes during storage. Clarification of mulberry juice was improved by adding several filter aids, fining agents, and enzymes, followed by filtration and centrifugation. Several fining agents, including chitosan, chitin, PVPP, gelatin, and casein at a concentration of 1%, and combination of ultrafiltration and centrifugation at 8,000 rpm were not suitable for clarification of juice owing to strong adsorption of anthocyanin pigment. Combination of $0.01\;{\mu}m$ membrane filtration and centrifugation at 8,000 rpm was effective for clarification of mulberry juice. Browning of minimally processed mulberry juice was inhibited significantly by adding 200 ppm sodium hydrosulfite, and 0.1% L-ascorbic acid (L-AsA) and 0,1% citric acid (CA) also showed considerable browning inhibition. Combination of L-AsA and CA, which was moderately effective for browning inhibition of juice, may be useful as a sulfite alternative for mulberry juice. Optimum sugar ($^{\circ}Brix$)/acid ratio and commercial sterilization of minimally processed mulberry juice were approximately 40 and 10 min at $85-90^{\circ}C$, respectively.

• Journal of Korea Water Resources Association
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• v.53 no.9
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• pp.681-690
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• 2020

Generally, the design capacity of the rainwater harvesting unit is determined by trial and error method that is repeatedly calculating various analysis scenarios with capacity, reliability, and rainwater utilization ratio, etc. This method not only takes a lot of time to analyze but also involves a lot of calculations, so analysis errors may occur. In order to solve the problem, this study suggested a way to directly determine the minimum capacity to meet arbitrary target reliabilities using the global optimization method. The method was implemented by simulation model with particle swarm optimization (PSO) algorithms using Python language. The pyswarm that is provided as an open-source of python was used as optimization method, that can explore global optimum, and consider constraints. In this study, the developed program was applied to the design data for the rainwater harvesting constructed in Cheongna district 1 in Incheon to verify the efficiency, stability, and accuracy of the analysis. The method of determining the capacity of the rainwater harvesting presented in this study is considered to be of practical value because it can improve the current level of analytical technology.

• Journal of Environmental Health Sciences
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• v.6 no.1
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• pp.1-9
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• 1979

An experimental study was carried out to develop a rural type toilet of which the effluent could not transmit parasitic diseases at a village in Kangwon Province, Korea, during the period of January through December 1978, A drum tank (dia. 57cm$\times$90cm) and a cement tank (100cm$\times$100cm$\times$100cm) were filled with human excreta collected from toilets of the villages (the ratio of feces to urine was estimated approximately 1: 5) at once and three threecompartment toilets were constructed and used by people. pH, temperatures and viability of parasitic eggs were examined with the content of toilets. Rusults are summarized as follows: 1. pH increased from 7.0 at the beginning of experiment to 7.5 or 8.0 after 4 months of storage in drum tank as well as in cement tank and so did from 7.0~7.5 in the first tank to 8.0~8.5 in the third tank of all three-compartment toilets. 2. Temperatures of content at middle part of toilets in January through March ranged from 2 to 6$\circ$C which were 2-4$\circ$C higher than those of air, and those of lower part were again 1~2$\circ$C higher than of middle part. but temperatures of air, at middle part andat lower part in April were 14$\circ$C, 9~10$\circ$C and 8~9$\circ$C respectively, in July 29$\circ$C, 20~21$\circ$C and 19~20$\circ$C respe ctively and in October 17$\circ$C, 14$\circ$C and 14~13$\circ$C respectively. 3. All the parasitic eggs were degenerated about 4 months after filling drum tank with human excreta on 10th April while 10% of eggs were degenerated on 15th May, and all the eggs were degenerated about 4 months after filling cement tank on 24th August while about 10% were degenerated on 11th September and 20% on 4th October. 4. Degeneration rates of eggs were only 5~15% at 5cm below surface in the first tanks of three-compartment toilets while 45~65% at 50cm below, and concentration rates of eggs in second tanks were 8~12% of those in first tanks and only a few eggs were found in third tank but all of them were degenerated. Specific gravity of liquid of 1.022~1.024 in second tanks was not enough for overflowing eggs into third tanks.

• The KIPS Transactions:PartC
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• v.14C no.5
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• pp.431-438
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• 2007

RFID system is core technology that construct ubiquitous environment for replacement of barcode technology. Use ratio of RFID system rapidly increase because the technology has many good points such as identification speed, storage space, convenience etc. But low-cost tag operates easily by query of reader, so the system happened user privacy violent problem by tag information exposure. The system studied many ways for security application, but operation capability of low-cost tag is about $5K{\sim}10K$ gates, but only $250{\sim}3K$ gates allocated security part. So it is difficult to apply security to the system. Therefore, this scheme uses dividing 64 bits and reduces arithmetic, so proposed scheme provide mutual authentication that can apply to low-cost RFID system. Existing methods divide by 4 and used 96 bits. However, that reduces 32 bits length for lightweight and reduced from communication number of times of 7 times to 5 times. Also, because offer security by random number than existing scheme that generate two random numbers, that is more efficient. However, uses hash function for integrity that was not offered by XOR arithmetic and added extension of proposed scheme. Extended scheme is not offered efficiency than methods that use XOR arithmetic, but identification distance is mode that is proposed secure so that can use in for RFID system.