• Journal of the Korea Organic Resources Recycling Association
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• v.5 no.1
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• pp.33-42
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• 1997

It is not long since treatment of food waste became a social problem. However, it is a fact that there have been a lot of debates on the treatment of food waste since several years ago. At present, two ways of disposing food waste are under great interest in Korea and Japan. One is drying of food waste at high temperature. The other is disappearance type, in which analysis by microorganism takes place with continuous supply of a bulking agent for a certain period of time that was stored in a reactor. In our laboratory, Disappearance type Food Waste Disposer is under interest, and experiments regarding condition establishment for efficient analysis of food waste were conducted. As preceding experimentation, experiments were done with regard to the selection of a substance to be used as a bulking agent, improvement by addition of a substance which maximizes initial growth of microorganism, and a concentration change in rank odors generated by reaction with deodorizer (absorbent). The results turned out to be satisfactory.

• Journal of Food Hygiene and Safety
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• v.13 no.2
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• pp.77-82
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• 1998

As a fundermental research for quality stailization of herb extract, the effects of water activity on microbial growth in herb extract were investigated. Herbs-Panax ginseng, Cinnamomum cassia, Lycium chinense, Zyzyphus jujuba, Lindera obtusilobum-were mixed and extracted with water at $80^{\circ}C$ and concentrated at $75^{\circ}C$. Water activity of the herb extract was adjusted to 0.86, 0.80 and 0.69, using water activity analyzer. The extracts were incubated for 180 days at $40^{\circ}C$ and then examined microbial cell counts and some physicochemical properties. In the extract of $a_{w}$ 0.86, 18 CFU/g of initial viable cell was increased to 80 CFU/g with 90 days of incubation and to 190 CFU/g 180 days of incubation. In the extract of $a_{w}$ 0.80, 24 CFU/g of initial viable cell was also increased to 83 CFU/g during the 90 days of incubation and to 170 CFU/ g for the 180 days of incubation. However, in the extract of $a_{w}$ 0.69, viable cell after 180 days of incubation was remained at almost the same level as initial viable cell. pH of herb extract was reduced in proportion to the decrease in water activity. The TLC (thin layer chromatography) patterns of ginseng saponins of herb extract did not show any significant changes after 180 days of incubation. Growth of pathogenic microorganisms was inhibited more with lower water activity of the herb extracts. In the herb extract inoculated with Candida albicans and Aspergillus niger, initial viable cells of 150 and 140 CFU/g were decreased to 30 and 20 CFU/g, repectively, after 30 days of incubation at $28^{\circ}C$. In the case of herb extract inoculated with Escherichia coli, Staphylococcus aureus, and Pseudomonas aeruginosa, growth of the bacteria was totally inhibited even after 30 days of incubation at $37^{\circ}C$.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.15 no.1
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• pp.74-82
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• 1982

In the previous study, we have reported the effect of lowering water activity of sodium chloride, sugars and polyols. In this study, water activity($a_w$)of various model Preparations of Kamaboko was measured and ability of lowering $a_w$ of starch, glycine and sodium lactate was discussed. In addition, the aw measurements were also compared to the predicted values of au which were derived from the equation of Raoult's law and the linear slope method by Sloan ana Labuza. The effect of starch on lowering $a_w$ was very low, and glycine was more effective than starch. Sodium lactate was shown to be the most effective among humectants examined. When it was added by $7.5\%$, the $a_w$ of model Kamaboko A was reduced to 0.93-0.94. Generally, prediction by the equation of Raoult's law turned out to be useful for determining $a_w$ lowering effect of humectants, excepting sodium chloride and sodium lactate. The equation of regression derived from the least squares could be applied to Predicting au in the model Kamaboko.

• International Journal of Highway Engineering
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• v.7 no.2 s.24
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• pp.45-55
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• 2005

It is known that the Q/C(Quality Control) in the early age of portland cement concrete(PCC) pavement gives a huge effect on long term pavement performance. Thus, many studies regarding the construction of PCC pavement have focused on how to assure construction quality at the early age stage. Curing is one of the most important factor in Q/C of PCC pavement. Membrane curing that protects the evaporation of moisture by placing an impermeable layer on the slab surface is the most common practice for curing the PCC pavement. In order to improve the membrane curing practice, the rate of curing compound should be optimized. However, the optimum rate of curing compound considering Korean weather and environmental conditions has not been specified in the pavement construction specifications. In this study, a proper application rate was recommended in terms of minimizing evaporation with several full-scale tests where various rates of curing compound have been applied. Four test sites on the expressway were enlisted during the summer of 2002 and 2003. Application rates tested were in the range of $0. The rate of evaporation, the temperature pattern of the slab and the pulse velocity of concrete surface have been monitored at each test construction. The result from this study showed that the rate of current construction was approximately $160ml/m^2$ and that approximately $400ml/m^2$ of curing application was recommended as the proper rate for minimizing the moisture evaporation.

• Journal of the Korea Organic Resources Recycling Association
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• v.7 no.2
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• pp.57-64
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• 1999

The purpose of this study is to establish effective conditions for controlling $CH_4$, $N_2O$ emission from organic Waste / wastewater treatment processes. Continuous and batch experiments were conducted to treat the micro algae from polluted and eutrophicated lakes through the thermophilic oxic process. The microalgae used were mainly Microcystis sp.(collected from eutrophic lake) and Chlorella sp. (cultured in laboratory) Wasted cooking oil was added by aid-heating source. Physico-chemical components of sludges and microalgae were analyzed. In batch experiments, air supply was changed from 50ml/min to 150ml/min. The temperature. water content and drained water were affected by the air flow rate at initial stage. However, there was almost no influence of air flow rate on them in middle and last stages. At air flow rate of 100ml/min, the degradation rate of organic material was higher than that at other air flow rates. $CO_2$ concentration in exhaust was proportional to the strength of aeration, especially at initial stage when degradation was active. $CH_4$ with low concentration was detected only at starting stage when air diffusion was not enough. $N_2O$ production was not affected by variation of air supply. In continuous experiments no matter what the dewatering methods (with PAC and without PAC) and media (wood chip and reed chip) were changed, $N_2O$ was almost not affected by variation of injected air. Result showed that the reed chips using for lake purification could be used as media for thermophilic oxic process in lake and marshes area. $CO_2$ concentration was not so much affected by the change of dewatering methods and media types. $CH_4$ was not detected in the experimental period. So it can be shown that the thermophilic oxic process had been well operated in wide handling conditions regardless of media and dewatering methods.

• Journal of the Korean Applied Science and Technology
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• v.38 no.6
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• pp.1533-1542
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• 2021

Eco-friendly polyurethane can be defined as a highly utilized material used in various fields. The various structural properties of the synthesis of isocyanates and polyols provide versatility and customization for use in the manufacturing field. The characteristics of polyurethane vary widely from soft touch coatings to hard building materials like rocks. These mechanical, chemical and biological properties and ease of alignment are drawing tremendous attention not only in the field of research but also in related industries. In order to improve the performance of water-dispersible polyurethane materials, it can be derived through processes such as adjusting the blending of raw materials and adding additives and nanomaterials. This study highlights the basic chemical structure of eco-friendly water-dispersible polyurethane in the fields of medical science, automobiles, coatings, adhesives, paints, textiles, marine industries, wood composite materials, and clothing.

• Journal of the East Asian Society of Dietary Life
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• v.13 no.3
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• pp.197-215
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• 2003

This study was carried out to investigate the effects of added emulsifier and enzyme on the quality characteristics of Seolgiddeok with black rice powder, green tea powder, Lentines edodes powder, pumpkin powder during storage. Samlpes were divided into two groups, the emulsifier-enzyme added group and the control, and stored fur 4 days at 2$0^{\circ}C$. Moisture content was measured by the air oven method; the Hunter's cole. values by Lightness (L), redness (a), yellowness (b) value; the degree of gelatinization by the enzyme digestion method, and expressed as glucose content by Somogi-Nelson method. The degree of retrogradation was calculated as the retrogradation rate using the degree of gelatinization value, and total cell and mold counts were also measured. Texture and sensory characteristics were also investigated. The results are as follows: The emulsifier-enzyme group was significantly different from the control from each examination and the retrogradation of pumpkin Seolgiddeok with emulsifier-enzyme was delayed the most among samples tested.

• Journal of Korean Society of Forest Science
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• v.86 no.1
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• pp.1-8
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• 1997

Second year results are presented from a trial designed to quantify the reduction in radiata pine(Pinus radiata D. Don) seedling growth caused by competition from a range of important weed species on a moist North Island site in New Zealand. Radiates pine seedlings(1/0) were grown on the weed free control and with either herbaceous broadleaves, grass, broom, pampas, buddleia, or gorse. Resource(nutrient and water) levels were varied by factorial +/- irrigation and fertilizer treatments. Radiata pine seedling volume growth 21 months after planting was greatest when it was grown on the weed free control or in association with gorse, and was least when grown with either buddleia or pampas. There was no evidence that the effects of the weeds on seedling growth were mediated by either competition for water or nutrients. Tall, fast-growing species that overtopped the seedlings(broom, buddleia, pampas) had the greatest effect on seedling growth and the magnitude of the effect was correlated with degree of overtopping. This implies that shading or competition for light is probably an important factor.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.14 no.3
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• pp.139-147
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• 1981

In this study, by using Landrock method modified by Yokozeki (1973) and Koizumi (1980), water activity ($a_w$) of various model preparations of Kamaboko was measured and ability of lowering $a_w$ of humectants added such as sodium chloride, sugars and polyols was discussed. The results were as follows : 1 The effect of sodium chloride on lowering aw was the highest among all of examined. When $4\%$ sodium chloride as humectant was added to the model Kamaboko, the $a_w$ was reduced to 0.94 or below. 2. Among the sugars, glucose was so effective that it lowered $a_w$ to 0.96 by adding $10\%$, but it would cause browning reaction on the Kamaboko surface. 3. Glycerin was the most effective among the polyols. When it was added by $10\%$, the $a_w$ of Kamaboko was reduced to 0.95. 4. It was more effective to decrease $a_w$ to lower moisture content of model Kamaboko.

• Journal of the Korea Organic Resources Recycling Association
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• v.2 no.1
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• pp.51-64
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• 1994

To compost the food garbage with the dry bean curd and sawdust as the bulking agents, the method of high-speed fermentation by the characteristic microorganisms group was applied. The results of experiments are summarized as follows ; 1. Korean food garbage, which is high in water content, is difficult to compost only by microorganism fermentation without the addition of bulking agents such as dry bean curd cake and sawdust. 2. Weight reduction rates are ranging from 35.6% to 64.5% and varying with the composition of food garbage. The less weight reduction rate is, the longer continuous-fermentation is. And the color of compost is changing sequentially as yellow -> brown -> black. 3. Comparing with the controlled microorganism group, the weight reduction rate and $H_2CO_3$ production rate in the characteristic microorganism group fermentation reactors are higher. And the fermentation rate is satisfactory when the characteristic microorganism group is added. 4. The value of fermented composting as fertilizer diminishes, and the contents of Total Nitrogen, $P_2O_5$, $K_2O$ increase on the condition that the fermentation continues. However, the organic contents and C/N ratio diminish as the fermentation continues. 5. The high-speed fermentation technology demonstractes the possibility of recycling as well as the reduction of composting time provided that it is applied as a pretreatment process for composting.