• Resources Recycling
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• v.25 no.2
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• pp.60-68
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• 2016

In this study, earlier analyzed tetrapod, one of an original group of offshore constructions studied for manufacturability of the concrete using the properties of steel making slag aggregate. steel making slag aggregate assessment, RCS and Blast Furnace Slag : the 20 mm air-cooled slag and combinations by 50 %, aggregate properties on the most appropriate for the properties of recycled aggregate concrete optimal mix, and assessing it. Properties of concrete used to be derived are judged as to bury the studies show that the hollowing-out of the RCS, plastic sole use is in the workability of the aggregate, plastic in the 20 mm slag also assessed to be a slight disadvantage, but RCS by mixing air-cooled coarse and 50 percent to 20 percent 50 mm. Thus, steel making slag marine structures using recycled aggregate, in rapid chilled slag or air-cooled slag. The sole use of the aggregate them than to combine the aggregate of concrete. After they satisfy the quality standard quality shall be used will aggregate steel making slag who meet the criteria concrete manufacturing in general or par with the aggregate of concrete. Performance was assessed as to develop a more than that.

• Journal of the Korean Society for Precision Engineering
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• v.29 no.8
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• pp.896-905
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• 2012

Recently, the application of the plastic material to automotive components and structures has steadily increased to satisfy demands on the saving of overall weight and the improvement of energy efficiency. The objective of this paper is to investigate the development of a bumper back-beam using a thermoplastic olefin (TPO). The bumper back-beam was designed to be manufactured from the injection molding process. In order to obtain a proper design of the bumper back-beam, three-dimensional finite element analyses were performed for various design alternatives. Stress-strain curves for different strain rates were measured by high speed tensile tests of the TPO to consider strain rate effects in the FEA. The influence of the sectional shape and the rib formation on the contact force-intrusion curves, the deflection and the energy absorption rate of the bumper back-beam was examined. From the results of the examination, a proper design of the bumper back-beam was acquired. The bumper back-beam consisting of TPO was fabricated from the injection moulding process and the vibration welding. Pendulum crash tests were carried out using the fabricated bumper back-beam. The results of the tests showed that the designed bumper back-beam can satisfy requirements of the federal motor vehicle safety standard (FMVSS). Through the comparison of the previously designed bumper back-beam with the newly designed bumper back beam, it was noted that the weight of the designed bumper back-beam is lighter than that of the previously designed bumper back beam by nearly 16 %. In addition, it was considered that the newly designed bumper back beam can improve recycling of the bumper back-beam.

• Journal of the Korea Organic Resources Recycling Association
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• v.23 no.1
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• pp.23-28
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• 2015

This study was conducted to evaluate the biodegradation characteristics of food waste on various collection systems using anaerobic batch test. The ultimate methane production from food waste in standard plastic garbage bags (sample A) was $285.6mL\;CH_4/g$ volatile solids (VS) which is the lowest, and reaction constant was $0.215d^{-1}$. The ultimate methane production from food waste in waste vessel based on RFID (sample D) was $493.4mL\;CH_4/g$ VS which is the highest, and reaction constant was $0.162d^{-1}$. The determinants of rate limiting step on all samples showed positive numbers, and the methane production step was found a rate limiting step.

• Journal of the Korea Organic Resources Recycling Association
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• v.4 no.1
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• pp.73-81
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• 1996

The expriment was carried out to clarify the fertilizer efficiency of a garbage-based compost in cultivation of leaf vegitables. 1. Only application of 8 tons per 10 of the compost did not have any growth injury to "Osaka-shirona" (a cultivar of Brassica pekinensis L.) in a pot experiment 2. In four continuous cropping with application of 3 tons per 10 a of the compost before every seeding, "Osaka-shirona" grew satisfactorily. 3. Osaka-shirona, spinich and garland chrysanthemum were cultivated under a plastic house applied with 2 tons per a of each of the garbage-based compost and cattle manure, delayed release fertilizer and bark compost on the market. There was no difference of the vegetable yields among the applied field, as well as of the contents of ${\beta}$-carotene, vitamin C, Ca and Fe.

• Resources Recycling
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• v.16 no.2 s.76
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• pp.56-62
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• 2007

In this study, we carried out the research on triboelectrostatic separation for heavy group plastics (PET, PVC) recovered from wet gravity separation. From the research on charging characteristic for the choice of charging materials, it was found that PP was optimum charging material to make high charging amount with opposite polarity for PET and PVC of heavy group. Therefore, we manufactured a charger of cyclone type using PP material for separation of PET and PVC. At optimum test conditions that used PP cyclone charger developed in this study, we developed a triboelectrostatic separation technique that can separate PET plastic up to grade of 98.5% and recovery of 86.2%. We established new separation technology that could recycle the PET and PVC heavy group plastics recovered from wet gravity separation.

• Journal of the Korea Concrete Institute
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• v.13 no.1
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• pp.54-61
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• 2001

As a part of the movement of natural resources conservation, there have been doing many recycling research works for obsolete aged tire, wasted plastic materials, etc. The purpose of this experimental study is to develop glass concrete by recycling wasted glasses as a cementitious constituent in concrete. First of all, the optimum replacement ratio of powdered waste glasses(PWG) can be determined through pilot compressive strength test on normal and high strength concrete cylinders, which have been made in various mix proportions by changing the replacement ratio of PWG. Then, further tests have been done to figure out mechanical properties of most desirable glass concrete with optimum replacement ratio of PWG, such as static modulus of elasticity, compressive and tensile strengths, flexural strength. On the other hand, the alkali-silica reactions by the mortar-bar method(KS F 2546) have been experimentally doing in various grain sizes of PWG, since the alkali in the cement has a tendency to react with the silica in the PWG. In can be confirmed from the test that glass concrete can have better workability than concrete with silica fume, and they are alike in compressive strength. It is concluded that wasted glasses can be used as pratical additives for economic and environmentally friendly concrete.

• Journal of the Korea Organic Resources Recycling Association
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• v.6 no.2
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• pp.113-129
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• 1998

To suggest the separate collection system of garbage in household, people's disposition was evaluated. It was indicated that garbage be collected daily to minimize the odor which was major nuisance from garbage. However, most people wanted to discharge garbage in two or three days interval, as they did not prefer frequent handling. So, proper size of garbage container was determined as two to three days capacity. In contrast with it, it was major opinion that dicharged garbage should be collected everyday by local government to eliminate the outdoor pollution. Plastic bag was the most popular container, as it could be used instantly. Price of the bag affected on the efficiency of reduction and separate collection of garbage. Low price increased the separate collection and decreased the reduction, while high price introduced the opposite result. So, the dual price system was suggested to enhance both objectives.

• Journal of the Korea Organic Resources Recycling Association
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• v.14 no.3
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• pp.138-147
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• 2006

In this study, the composition and physico-chemical characteristics of municipal solid waste (MWS) which was treated in national park area kyungnam-do landfill were investigated. It is necessary to measure the characteristics of MSW and sludge to build a waste treatment facility, the data-base and total managing of the landfill. This MSW was composed of 34.62% of food wastes, 36.05% of papers, 15.37% of plastics & vinyls, 2.28% of textiles, 3.33% of wood, 0.49% of rubber & leathers and others, respectively. Most of MSW are composed of food, paper and plastic waste and more than 90% was combustible waste. For three components, moisture is 29.84%, combustible component is 62.30% and ash is 7.86%. The chemical element has the high order of carbon, oxygen, hydrogen on the dry basis of wastes. Also, the low heating value of the MSW which is measured by calorimeter is calculated as 2377.8kcal/kg. low heating value of the sludge is calculated as 338.06kcal/kg.

• Journal of the Korean Society for Marine Environment & Energy
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• v.11 no.1
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• pp.46-49
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• 2008

Recycling glass fiber, 'F-fiber,' was obtained by the separation of the roving layer from waste FRP and the concrete products or structures were considered for its application. Experiment was carried out for the bending strength of aggregate (2.45 of cement) by weight and F-fiber (density of 1.45, volume ratio to all of the aggregate and the cement). Whereas the specimen containing 1% F-fiber showed the bending strength 23% higher than that without F-fiber after curing far 28 days, the one with 0.5% F-fiber did not give any change. It could be found, therefore, that the minimum mixing amount should be larger than 0.5% fur the strength reinforcement. One of the reinforcing concrete product, bench flume, containing 1% F-fiber showed 21% increment of bending strength In contrast to that without F-fiber.

• Proceedings of the Korean Institute of Resources Recycling Conference
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• 2005.10a
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• pp.97-106
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• 2005

현재 우리나라에서만 연간 약 26만들이 발생되고 있는 농업용 폐비닐은 재생원료로 재활용되어지면 국내외에서 그 용도가 매우 많으나 멀칭용으로 사용되었던 폐비닐은 그 오염도가 워낙 심하여 쉽게 재활용할 수 없는 처지이다. 즉 공급과 수요는 많으나 재생기술의 한계가 병목으로 작용하고 있는 현실이다. 따라서 간단하고 경제적인 방법으로 재활용할 수 있는 습식 및 건식 재생기술의 개발이 계속되어 요구되어 왔다. 강제 세척, 회전분리, 열풍 건조 및 압착성형을 이용한 새로운 간이습식공정을 통하여 멀칭용 농업용 폐비닐을 순도 95% 이상의 탄화 및 열화가 적은 압착 펠렛을 경제적으로 제조할 수 있었다. 이들의 재생 수지는 인장강도 $168.6{\pm}3.9kgf/cm^2$, 파단신을 315.8%, 인장탄성을 $2,551.8{\pm}50.1kgf/cm^2$, 굴곡강도와 굴곡탄성을 $166.7{\pm}7.4kgf/cm^2,\;5,716.2{\pm}242.2kgf/cm^2$ 그리고 충격강도는 $49.2kgf\;cm/cm$을 각각 보여 연질수지로써 기능하기 위한 충분한 성능을 보유하고 있음을 알 수 있었다. 또한 이들의 응용분야 확대를 위하여 fly ash 및 탄산칼슘을 배합하여 이들의 물성변화를 살폈다.