• Korean Journal of Food Science and Technology
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• v.40 no.4
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• pp.365-374
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• 2008

Plastics are comparatively new polymeric materials that are manufactured by chemical synthesis, making them different from natural materials such as wood, paper, stone, metal, and glass. Due to a wide range of properties, including processing capabilities and duration, plastics have become rapidly ubiquitous, being used in all industries, and have improved our quality of life. However, it is true that plastics cause environmental contamination problems that have become important social issues, such as environmental hormone leakage due to incineration or reclamation, difficulty in securing reclamation sites, and deadly poisonous dioxin generated by the incomplete incineration of waste plastic materials. To solve these problems, it is urgent to develop and commercialize degradable plastics that can be stably and conveniently used just as general plastics, and that are easily decomposed by sunlight, soil microbes, and heat generated from reclaimed land after use. This review presents recent worldwide trends in the development and marketing of environmentally degradable plastics.

• Korean Journal of Food Science and Technology
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• v.30 no.2
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• pp.272-277
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• 1998

In order to study storage stability of fresh jujube fruits (Zizyphus jujuba Miller) controlled atmosphere storage, polyethylene film packaging and non-packaging were compared. Jujube fruits were stored on the following gas compositions: 1.5% carbon dioxide and 5, 8, 10, 12% oxygen at $7^{\circ}C$, respectively. And 0.05 mm PE packaging and non-packaging were stored at $1^{\circ}C,\;4^{\circ}C\;and\;7^{\circ}C$. Safe storage period of Bokjo jujube fruits was four weeks when stored in CA condition of $O_2\;10%\;and\;CO_2\;1.5%$ in terms of their overall quality. The rate of weight loss was not much changed either by storage method of CA or by PE film packaging. In surface color the a value of jujube fruits increased but L and b values decreased during the storage period. Hardness showed the trend of increase in all the treatment for 2 weeks of storage while in CA it decreased more than the others after 4 weeks of storage. Soluble solids and titratable acidity were changed slightly. Vitamin C contents were gradually decreased in all treatments, but non-packed jujubes at $1^{\circ}C$ were slightly increased.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2021.05a
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• pp.271-272
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• 2021

The maintenance and repair work of sidewalk block pavement is a construction that requires a large amount of budget to be invested every year. It is important to establish an appropriate standards for estimating construction cost to ensure proper budgeting and quality. In this study, the standards for estimating the cost of maintenance and construction work for sidewalk blocks that can be applied to the construction volume classified according to the site conditions, construction type, and equipment use differentiated from new construction was established. As a result, the daily construction volume was presented by reflecting excavator and truck as equipment in the combination of paver and common worker. The re-installation was applied by separating the construction volume of sections with general blocks and induction/raised blocks based on the installation of sidewalk blocks after demolition. Generally if block cutting is necessary, the precision construction conditions using a cutting machine were taken into consideration to secure the construction quality. In addition, it has been revised to apply classified construction volume into A and B-Type depending on the park and site conditions.

• Journal of Korean Society of Forest Science
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• v.95 no.6
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• pp.751-758
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• 2006

To investigate soil management practices for increasing tree growth in arid regions of China, Xinjiang poplar (Populus alba var. pyramidalis) seedlings were planted in a nursery and windbreak and were treated with fertilizers (nitrogen and phosphorus) and absorbents (artificial; K-SAM and natural: Yuho (Artemisia ordosica)) at Dengkou in Inner Mongolia. Seedling height, diameter at breast height (DBH), biomass, and nitrogen (N) and phosphorus (P) concentrations were measured 1.5 years after the treatments. Soil texture was sandy loam for nursery and clay loam for windbreak, soil pH was 8.78 for nursery and 8.51 for windbreak, and total soil N concentration was 0.06% for nursey and 0.08% for windbreak. [n general, seedling height and DBH increased in the N fertilizer treatment compared to control or other treatments both in nursery and windbreak. Also seedling growth increased after the treatments of artificial and natural absorbents in windbreak. Total above- and belowground biomass increased after the N + P treatment. Foliage N and P concentrations following N and/or P treatments were same in the nursey, however, they significantly increased in the windbreak indicating N deficiency. It appeared that N was a limiting factor for early growth of Xinjiang poplar seedlings and artificial and natural absorbents (K-SAM and Yuho) would be useful to increase seedling growth in the arid region.

• KOREAN JOURNAL OF PACKAGING SCIENCE & TECHNOLOGY
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• v.27 no.1
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• pp.1-8
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• 2021

This study is for the application of functional antibacterial packaging to fresh food. Zeolite/Zinc-polypeptide was coated on PP film at concentrations of 5%, 10%, and 15%, degree of dispersion was verified through FESEM and FT-IR analysis. In addition, the antibacterial and antifungal properties of the films were analyzed according to the control group and the concentration of coating materials. As a result, the degree of dispersion of coating material was irregular but wide, depending on the concentration of Zeolite/Zinc-polypeptide on the surface of PP film. The antibacterial effect against E. coli was over 99.9%, and the growth of R. oryzae was inhibited about 70%. Therefore, it was confirmed that Zeolite/Zinc-polypeptide had antibacterial and antifungal properties against E. coli and R. oryzae even after coated on PP film. In conclusion, Zeolite/Zinc-polypeptide coating film is expected to be effective in preventing corruption and improving the shelf life of fresh food as a functional packaging material. In order to be applied to various fresh foods in the future, storage experiments are additionally required with temperature and humidity conditions according to fresh foods.

• Korean Journal of Food Science and Technology
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• v.33 no.4
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• pp.479-485
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• 2001

A study of the levels of phthalate and adipate esters, which are suspected as endocrine disruptors, in food packaging wraps and packaged foods were carried out. Among 11 wrap samples, 8 household wraps purchased at retail markets were polyvinyl chloride(PVC) and polyethylene(PE), while 3 commercial wraps at wholesale markets were PVC. All of 51 selected food samples, such as 12 samples of vegetable, 11 samples of fruit, 6 samples of bread and rice cake, 4 samples of meat and poultry, 4 samples of fish and 14 samples of side dish, packaged with commercial PVC wraps containing adipate esters were purchased at retail markets. The level of di-(2-ethylhexyl) adipate(DEHA) and diisononyl adipate(DINA) was from 2.2 to 17.9% and from 4.2 to 22.3% in household PVC wraps, respectively. In the commercial PVC wraps, the level of DEHA showed from 18.3 to 22.5%, while other phthalate esters were not detected. The phthalate and adipate esters were not detected in PE wraps. The level of DEHA in packaged foods, such as vegetable, fruit, bread and rice cake, meat and poultry, fish and side dish, were determined up to $8.2\;{\mu}g/cm^2,\;17.4\;{\mu}g/cm^2,\;31.0{\mu}g/cm^2,\;8.3\;{\mu}g/cm^2,\;2.1\;{\mu}g/cm^2$ and $92.3\;{\mu}g/cm^2$, respectively. The results suggested that migration levels of DEHA in foods were closely related to the fat content, wrapping condition of food and stroage time and temperature.

• Resources Recycling
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• v.19 no.6
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• pp.36-42
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• 2010

Researches on resources recycling in the field of construction have made an extensive progress such as recycled aggregate of waste concrete and recycling of asphalt. On the other hand, there are almost never researches on pavement method with used waste frying oil. In South Korea, 0.2 million ton used waste frying oil is discharged every year. It is guessed that about 0.1 million ton used waste frying oil can be collected. If used waste frying oil is recycled, it is expected that disuse cost will be reduced and water pollution of rivers will be prevented. Therefore, the purpose of the study was to evaluate on mechanical features (strength, water resistance, chemical resistance, abrasion resistance, freezing and thawing resistance and permeable coefficient) whether dense graded permeable concrete mixing silica sand with flexible alkyd resin manufactured by making ester reaction with collected used waste frying oil to make alkyd resin could be applied to road pavement for non-roadway. The results of the study were as follows. In flexural strength, it had 1.6 times as much as road design standard 4.5MPa. In water resistance, chemistry resistance and freezing and thawing resistance, they had lack of strength in early age. As age went by, they didn't have large changes. And curing temperature had phenomenon of increase in strength at rather low temperature than high temperature by glass transition temperature of resin. Therefore, considering workability, strength and durability when it was applied to road pavement, it was reasonable that the mixing ratio of flexible alkyd resin was 10~15% in comparison with silica sand weight.

• Journal of Nutrition and Health
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• v.55 no.4
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• pp.476-491
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• 2022

Purpose: The purpose of this study was to evaluate the energy and nutrient contents of home meal replacement (HMR) rice products per single serving package based on nutrition labels. Methods: The market research was conducted from February to July 2021 on products sold on the internet, at convenience stores, etc. A total of 406 products were investigated. The products were divided into the following 6 classifications: instant rice (n = 45), cup rice (n = 64), frozen rice (n = 188), rice bowls with toppings (n = 32), gimbap (n = 38), and triangular gimbap (n = 39). Results: The mean packaging weight per serving was the highest in the rice bowl with toppings at 297.1 g, followed by cup rice (264.0 g), frozen rice (239.5 g), gimbap (230.2 g), instant rice (193.4 g), and triangular gimbap (121.6 g) (p < 0.001). The energy per serving package for the rice bowl with toppings was significantly the highest at 496.0 kcal (p < 0.001). The sodium content per serving package of gimbap was the highest at 1,021.8 mg and that of the instant rice was lowest at 37.4 mg (p < 0.001). The price per serving package of the rice bowl with toppings at 4,333.8 won was the highest. The contribution to the daily nutritional value per serving package of all types of HMR rice products surveyed showed an average range of 10-25% for energy, 11-22% for carbohydrates, and 2-51% for sodium. Conclusion: These results indicate the energy and nutrient contents of HMR rice products, vary by type. Therefore, consumers should review the nutrition labeling to select an appropriate HMR rice product based on their intended consumption.

• Proceedings of the Korea Water Resources Association Conference
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• 2020.06a
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• pp.129-129
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• 2020

전국적으로 약 18,000여개가 축조되어 있는 농업용 저수지는 국내농업용수 사용량 중 약 60%를 공급하는 핵심 농업기반시설로서 홍수기에 풍부한 수량을 저류한 후 관개기 혹은 갈수기에 주로 논벼 재배지역에 용수를 공급한다. 최근에는 가뭄에 의한 피해 심각성이 증가함에 따라 농업용 수확보대책 수립, 저수지 준설, 관정개발, 양수저류 등의 다양한 대응 방안을 마련하여 농업가뭄 극복을 위해 노력하고 있으나, 농업용수공급은 현장 물관리자의 경험을 토대로 공급되고 있어 공급량 관리가 정성적이고 제한적인 한계가 발생한다. 따라서, 농업용수의 효율적인 물 관리, 수원공으로부터 물공급의 합리적인 분배, 말단 수로 및 포장까지 안정적인 용수공급을 위한 물공급 및 분배 효율 분석이 필요하다. 본 연구에서는 서산지역의 신송저수지를 대상으로 2019년 5월부터 8월까지 통수일지 자료를 활용하여 농업용수 물공급 및 분배 모의, 관개효율을 분석하였다. 이를 위하여 부정류해석이 가능한 SWMM (Storm Water Management Model) 모형을 기반으로관개지구 용수공급 체계 네트워크와 들녘별로 용수공급이 가능하도록 구축하였고, 해당 지구의 실제 통수 시 수위 유량 계측을 통해 모델의 필수 변수 입력자료를 구축하였다. 전체면적 대비 수혜면적 비율과 전체 관개량 대비 해당 간선의 관개량 비율의 비교를 통해 수혜면적에 따른 관개효율을 분석하였으며, 각 수로별 공급량 대비 관개량 비율을 산정하여 수로별 관개효율을 분석하였다. 농업용수공급 효율 평가 결과는 수혜면적의 용수부족지역 파악, 시기별 용수배분의 공간적인 분포 모니터링 등 농업용수 이수대책에 활용하여 농업가뭄 상황 시 효율적인 물 배분 및 관리에 활용될 수 있을 것으로 판단된다.

• Journal of the Korean Society of Hazard Mitigation
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• v.7 no.3
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• pp.59-67
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• 2007

For the time being, HMA test specimen were prepared by Marshall Compaction Method for hot mix asphalt design and evaluated the mechanical properties of HMA at the specified air voids. Gyratory Compaction can simulate the field compaction process and measure the degree of compaction just after field compaction in laboratory. Superpave mix design with Gyratory compactor has been used for characterization of performance. The curve of gyratory compaction can be used to evaluate the permanent deformation potential of hot mix asphalt. In this paper, couple of indices for hot mix asphalt have been showed for hot mix asphalt in Korea. The major properties from gyratory compaction curve are compaction energy index and traffic compaction index. The specific guide line for the potential of hot mix asphalt has been proposed.