• Korean Journal of Organic Agriculture
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• v.22 no.4
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• pp.695-703
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• 2014

We experimented with the effect of oleic acid and its appropriate concentration to prevent powdery mildew eco-friendly in a cucumber greenhouse cultivation. 'Baekbongdadaki' (Nongwoo Bio. co. Korea) was treated in the plastic greenhouse at Sangmyung University. We treated four levels of concentration of oleic acid, which were 0, 2000, 4000, 6000, and 8000 ppm. There were investigated diseased severity, diseased leaf area, control value, and pesticide injury. The degree of control values by oleic acid treatments was investigated at 3 days after treatment. The recurrence of powdery mildew was checked for 55 days. The day and night temperature in the greenhouse were controlled to 23 and $15^{\circ}C$ respectively. The humidity inside the greenhouse was not controlled to prevent outbreak of the disease. From the experimental results, oleic acid was very efficient to control powdery mildew. 2000 ppm of oleic acid was shown to be the most control efficiency without any pesticide injury. The recommended method to treat it was to spray three times every 3 weeks.

• Food Science and Industry
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• v.50 no.2
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• pp.2-11
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• 2017

Packaging is the last defensive barrier that protects food products from insect infestation during storage. However, though packaging films are hermetically sealed, insects can still be attracted by strong olfactory cues and penetrate through packaging materials, resulting in contamination. Insect contamination may cause consumers to be repulsed by contaminated food products. Especially, it is well known that stored-product insects cause critical problems in the cereal industry by inducing quantitative and qualitative damages to the grain products. The contaminations are caused by insects' metabolic byproducts and body parts, consequentially caused customer repulsion. Therefore, it is necessary to repel and control insects. However, management systems for storage insects in food industry have been inadequate for many years. Synthetic pesticides has been widely used, but pesticides may accumulate in foods, causing acute and chronic symptoms in consumers. For this reason, there is a growing need for the development of natural insecticides that can replace synthetic pesticides. Thus, various reports about anti-insect packaging materials and strategies to repel insects were introduced in this study. Furthermore, we suggested new strategies to develop an insect-repelling active packaging materials which could be applied in the food packaging industry.

• Journal of the Mineralogical Society of Korea
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• v.27 no.4
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• pp.251-262
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• 2014

Inorganic binders were studied in order to apply a conservation material for stone monument. A pure inorganic binder and 3 species of inorganic binder which contain additives on the basis of a pure inorganic binder were selected as test samples. Through the application of inorganic binders on Geochang granite investigate their influences on stone. pH 4.0 and 5.6 acid solution, respectively were manufactured on the basis of the acidity of domestic rainfall. Alkaline water with pH 8.0 and deionized water with pH 6.85 were prepared as control group. Changes in weights of inorganic binders were not definite according to the acidity of water while weight losses in inorganic binder type were greater after reaction with the water. The compressive strengths of pure inorganic binder was largest before the test but its decrease rate were larger after reaction with the water. Water absorption rate of inorganic binders are 6.72 to $12.44kg/m^2{\cdot}t^{1/2}$ after reaction with the water. Such high absorption was considered that it forced water to move deep into inorganic binder and made the components of inorganic binder dissolve. Acidities of the water of pH 4.0, 5.6, 6.85 and 8.0, respectively were changed to pH 9.0-10.0 after reaction with the inorganic binders. Ion concentrations in the water changed after reaction with the inorganic binders and $Mg^{2+}$, and $K^+$ significantly increased, dissolved from the binder. The high concentration of ions detected showed that the binder reacted with water and formed white salts with high solubility such as $MgSO_4{\cdot}nH_2O$, $KNO_3$. Ion concentrations significantly decreased from the binder after treatment with consolidant and water repellent.

• Journal of Bio-Environment Control
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• v.21 no.3
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• pp.299-304
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• 2012

In this work, we experimented with the two-fluid fogging system that eco-friendly prevents whiteflies in greenhouses in order to find the optimal concentration of oleic acid supplied through the system and to evaluate the control value of three consecutive treatments. The first experiment, which was to find the optimal concentration of oleic acid, used "Dotaerang Gold" tomatoes grown in stand-alone plastic greenhouse at Buyeo Tomato Experiment Station. We tested three levels of concentration of oleic acid, which were 0, 2000, and 4000 ppm. The second experiment, which was to evaluate the control value of three consecutive treatments of oleic acid, used "Rokusanmaru" tomatoes grown in Venlo type glasshouse at Gyeonggi-Do Agricultural Research & Extension Services. In this experiment, oleic acid of 2000 ppm was applied three times with two days intervals. The number of whiteflies was counted 2 two days after the last application of oleic acid. Even when oleic acid was not being applied, the two-fluid fogging system was run from 9:00 am to 5:00 pm whenever the temperature is higher than $25^{\circ}C$ or the humidity is lower than 75%. In the first experiment, the control value was 81.6% with 2000 ppm of oleic acid and 93.6% with 4000 ppm. It means that the higher the concentration is, the greater the control value. In the second experiment, 2000 ppm treatment resulted in 85.8% of the control value, which is higher than the required standard for insecticides. Hence, spraying oleic acid with the concentration of 2000 ppm three times with two days intervals turned out to be a very effective in the eco-friendly prevention of whitefly.