• Journal of the Institute of Electronics and Information Engineers
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• v.49 no.12
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• pp.149-155
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• 2012

SSD is a storage device of having high-performance controller and cache buffer and consists of many NAND flash memories. Because NAND flash memory does not support in-place update, valid pages are invalidated when update and erase operations are issued in file system and then invalid pages are completely deleted via garbage collection. However, garbage collection performs many erase operations of long latency and then it reduces I/O performance and increases wear leveling in SSD. In this paper, we propose a new method of de-duplicating valid data and recycling invalid data. The method de-duplicates valid data and then recycles invalid data so that it improves de-duplication ratio. Due to reducing number of writes and garbage collection, the method could increase I/O performance and decrease wear leveling in SSD. Experimental result shows that it can reduce maximum 20% number of garbage collections and 9% I/O latency than those of general case.

• Journal of the Institute of Electronics Engineers of Korea SC
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• v.46 no.6
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• pp.21-27
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• 2009

As portable electronic systems being used more often, it becomes a more important issue to lengthen the lifetime of the power battery of the system, for instance, by developing batteries of a higher efficiency. A simple as well as practical method to lengthen the lifetime is to use multiple batteries that are connected in parallel. But in this paper we present a new idea in using multiple batteries, with which the residual energy of the battery can be used in the sense of recycling. The idea is based on a usual phenomenon that a battery cell that has been used until its voltage has dropped below a reference level may still have some residual energy, due to which the voltage can recover when the cell takes a rest for a while. As a practical realization scheme of this idea, a multi-cell configuration method with a cell selection switch is introduced, and its feasibility has been examined by performing experimental observations on the behavior of battery discharge. It has been found that the lifetime of an Alkaline primary battery cell can be lengthened approximately by one or two hours with the proposed method.

• Resources Recycling
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• v.18 no.2
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• pp.30-38
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• 2009

In this research, we studied the scale-up triboelectrostatic process for separation of PVC from higher gravity fraction of plastic wastes produced from wet gravity separation process. High density polyethylene (HDPE) was found to be the most effective materials for a tribo-charger in the separation of plastic tailings. In a commercial scale triboelelctrostatic separator unit, using the HDPE pipe-line charger, a grade of 99.1% with PET, PS and others and a recovery of 86% was obtained under optimum conditions at over 250 kV/m electric field, a splitter position of -8 cm from the center, and less than 40% relative humidity. The developed unit can process the plastic wastes at a 300 kg/h, and the product can be utilized as RPF or RDF of over grade 2.

• Journal of the Korean Recycled Construction Resources Institute
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• v.4 no.4
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• pp.371-378
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• 2016

In this study, a small portable sorting pilot for separation that can be used in dismantling construction site, which is the stage of construction waste generation, was developed, and its separation efficiency was evaluated to increase the actual recycling rate of the construction waste. The pilot was developed as portable sorting pilot for separation of 6 ton capacity that can handle one arm roll box within a $15m^2$ area in consideration of narrow places in the downtown area where a number of dismantling sites are located and various processes performed in the dismantling sites. In order to evaluate the efficiency performance of the developed device, the separation and sorting were carried out ten times with respect to trommel rotational speed RPM 2-3, 4-6 and 7-8. According to the results, the highest efficiency of about 90% was shown at RPM 6-7.

• Resources Recycling
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• v.16 no.5
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• pp.71-76
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• 2007

The mixed plastic waste generated from households after hand-picking and/or mechanical sorting processes amounts to 1,750,000 ton in 2006, and most of these waste are finally end up with landfill and/or incineration due to the lacks of separation technologies and economical reasons. The mixed plastic wastes can not be used as raw materials for chemical and/or thermal recycling processes because of their high content of PVC(upto 4.0 wt.%). In the present research, gravity separation system has been developed to remove PVC from the mixed plastic waste and to recover the PO-type plastics. This system mainly consists of air classification, magnetic separation, one-step crushing, feeding system at fixed rate and wet-type gravity separation system. The gravity system based on centrifugal separation has been developed at capacity of 0.5 ton/h and it consists of mixing, precleaning, separation, dewatering, recovery system and wastewater treatment system, etc. The main objective of this process is to achieve high separation efficiency of polyolefins with less than 0.3 wt.% PVC content and less than 10% moisture content in the final products. In addition, a crushing unit of with 8 rotor system is also developed to improve the crushing efficiency of soft-type plastics. The system with a capacity of 1.0 ton/h is developed and operational results are presented.

• Resources Recycling
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• v.6 no.3
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• pp.15-21
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• 1997

Flyash from a coal-hed power plan1 is produced approximtcly 3 million tons m 1996 and causes the serious environmentalpmblem due to the disposal in the ash pond. Flyash is an accepted additive in concrete where it adds strength, sulfate ateresistanceand reduced cost, provided acccptablc levcls of unbunrned carbon are mmtmed This papzr describes to investigate thc technicalfeasibility of a dry triboelcctrostatlcp roccss to scparate unburned carbon h m f lyash into economically valuable produck Puliclesof unburned carbon and flyash can be impded positivc and negative surface charzes. rcapeclively. with a copper tniochargcr dueto dirferences in the work function values of thc particles and the tnbacharger. and cm he separated by passing thcm throuph anexternal electic field. A laboratory s d e separation system consists of r sacw feeder for ash supply, a tniocharger, verticalcollecling copper plates, power supplies, a flow meter, and a fan. Separation tests taking into account separahian efficiency and ashrecovery showed that flyash recovery was sh-nngly dependent an thc tnbocharger geomzhy, elect"c ficld strength. flyssh s ~ c a,n dash feeding late. Optimal separation conditions were flyash size less than 125 Fm and electric field shcngrh of 200 kV1m. Ovcr 80%of the flyash with 7% lass on ignition was recovered at wrbon contznts less than 3%bon contznts less than 3%

• Clean Technology
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• v.17 no.4
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• pp.306-313
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• 2011

Flux or solder is used in soldering process for manufacturing electronic parts such as printed circuit boards (PCB). After soldering process, residual flux and solder paste on the parts should be removed since their residuals could cause performance degradation or failure of parts due to their corrosion and electric leakage. Ozone depletion substances such as 1,1,1- trichloroethane (TCE) and HCFC-141b have widely been using for removal of residual flux and solder paste after soldering process In manufacturing of electronic parts until now. In this study, non-aqueous cleaning agents without flash point were developed and applied to industrial field for replacement of cleaning agents with ozone depletion. In order to develop non-aqueous cleaning agents without ethers, esters, fluoride- type solvents. And their physical properties and cleaning abilities were evaluated, and they were applied to industrial fields for cleaning of flux and solder on the PCB. And vacuum distillation apparatus were operated to determine their operating conditions and recycling yields for recycling of used cleaning agents formulated in this study. As a result of physical properties measurement of our formulated cleaning agents, they were expected to have good wetting and penetrating power since their surface tensions were relatively low as 18.0~20.4 dyne/$cm^2$ and their wetting indices are relatively large. And some cleaning agents holding fluoride-type solvents as their components did not have any flash point and they seemed to be safe in their handling and storage. The cleaning experimental results showed that some cleaning agents were better in their cleaning of flux and solder paste than 1,1,1-TCE and HCFC-141b. And industrial application results of the formulated cleaning agents for cleaning PCB indicated that they can be applicable to industry due to their good cleaning capability in comparison with HCFC-141b. The recycling experiments of the used formulated cleaning agents through a vacuum distillation apparatus also showed that their 91.9~97.5% could be recycled with its proper operating conditions.

• Journal of the Korea Organic Resources Recycling Association
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• v.1 no.2
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• pp.287-298
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• 1993

In this study, generation characteristics and distribution situation of the animal fat residue were investigated to identify it's management problems and to propose alternatives for the recycling and final disposal. Generation sources were the meat distribution net-work including about 170 slaughterhouses, 280 meat-packing plants, thousands of meat shops and restaurants etc. The daily total amount of the animal fat residue is about 700 ton/day. More than 60% of the generation sources were concentrated in Seoul metropolitan area. The residue was collected by about 300 men using old-fashioned devices like handcarts, bike and auto bike, transported to the recycling plants by about 60 collection agencies. The residue was processed to produce by-products such as grease, tallow, animal feed ingredient in the recycling plants. At present, however, a great number of unlicensed, and mostly small rendering processors without having pollution control facilities do the unlawful business. These small, old fashioned and unorganized businesses are creating environmental problems by disposing the waste in improper ways such as open burning and dump. Improvement of the distribution network, the large-scale plants, and the estabilishing proper infrastructures were suggested to overcome the problems for the sound fat residues reprocessing industry.

• Proceedings of the Korean Society for Agricultural Machinery Conference
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• 2017.04a
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• pp.116-116
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• 2017

2012년 국내 총 폐기물(지정폐기물 제외) 발생량은 382,009 톤/일 으로 이 중 12.8%를 차지하는 생활폐기물 중 음식물 채소류폐기물 발생량은 13,209 톤/일 으로 대부분 소각 후 매립 처리되고 있다. 본 연구에서는 고수분 음식물 및 농업 폐기물을 재활용한 고형연료 제조에 필요한 열분해장치를 개발하고 실험을 통해 그 성능을 확인하고자 하였다. 본 연구를 위해 건조용량 50 kg/hr인 실험실용 열분해장치를 제작하였다. 건조 처리된 농업폐기물과 음식물 쓰레기를 열분해용 실험 원료로 사용하였다. 원료종류, 열분해 온도, 열분해 시간에 따른 농업폐기물과 음식물 쓰레기의 열분해 특성을 파악하였다. 농업부산물 건조물의 열분해 처리 결과, 열분해 처리능력은 평균 55.35 kg/hr, 저위발열량은 평균 3,333 kcal/kg으로 측정되었다. 농업부산물을 단순 건조 처리한 경우 고위발열량은 3,400 kcal/kg, 저위발열량은 3,090 kcal/kg으로 측정되어 열분해처리로 발열량이 향상됨을 알 수 있다. 음식물 쓰레기 건조물의 열분해 처리조건 및 결과, 열분해 처리능력은 평균 88.27 kg/hr, 저위발열량은 평균 4,016 kcal/kg으로 측정되었다. 음식물 쓰레기를 단순 건조 처리한 경우 고위발열량은 4,040 kcal/kg, 저위발열량은 3,686 kcal/kg으로 측정되어 열분해처리로 발열량이 향상됨을 알 수 있다. 열분해 처리능력은 연구목표치인 50 kg/hr보다 높게 나타났으며, 저위발열량은 연구목표치인 4,000 kcal/kg 보다 다소 높게 나타났다. 다만 저위발열량 측정 기준 함수율이 습량기준으로 약 10%로 추정되는 바 5%로 조절하고, 열분해 열풍온도를 $200^{\circ}C$ 까지 상승시키면 발열량이 훨씬 향상될 것으로 판단된다.

• Proceedings of the Korean Society for Agricultural Machinery Conference
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• 2017.04a
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• pp.117-117
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• 2017

2012년 국내 총 폐기물(지정폐기물 제외) 발생량은 382,009 톤/일 으로 이 중 12.8%를 차지하는 생활폐기물 중 음식물 채소류폐기물 발생량은 13,209 톤/일 으로 이중 음식물 폐기물은 탈수 후 사료 제조 또는 매립 처리되고 있다. 본 연구에서는 고수분 음식물 쓰레기를 재활용한 고형연료 제조에 필요한 건조장치를 개발하고 실험을 통해 그 성능을 확인하고자 하였다. 본 연구를 위해 건조용량 500 kg/hr인 실험실용 열분해장치를 제작하였다. 회사 구내식당 및 창원시에서 수거된 음식물 쓰레기를 실험 원료로 사용하였다. 건조공기 투입 온도에 따른 음식물 쓰레기의 건조 특성을 파악하였다. 음식물 쓰레기 건조실험 결과, 총 건조소요시간은 약 20시간 정도로 나타났으며, 건조속도는 약 2.90 %/hr로 나타났다. 건조시간은 연구 목표치인 1회당 15시간보다 5시간 소요된 것으로 나타났으나 투입 및 배출에 소요되는 예열 및 냉각 시간을 제외하면 약 16시간으로 연구목표치에 근접한 것으로 판단된다. 투입건조공기 온도에 따른 건조시간은 큰 차이를 보이지 않았으며, 특히 $155^{\circ}C$에서 21시간으로 나타나 향후 폐열 활용 시 $200^{\circ}C$ 이상의 고온의 공기를 사용하지 않아도 건조작업이 가능함을 확인하였다. 건조시간 단축을 위해서는 투입공기의 온도보다는 투입공기와 음식물 쓰레기의 접촉 면적이 큰 영향을 끼치는 것으로 판단된다.