• Transactions of the Korean Society of Mechanical Engineers B
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• v.39 no.3
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• pp.285-291
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• 2015

A centrifuge works on the principle that particles with different densities will separate at a rate proportional to the centrifugal force during high-speed rotation. Dense particles are quickly precipitated, and particles with relatively smaller densities are precipitated more slowly. A decanter-type centrifuge is used to remove, concentrate, and dehydrate sludge in a water treatment process. This is a core technology for measuring the sludge conveyance efficiency improvement. In this study, a smoothed particle hydro-dynamic analysis was performed for a decanter centrifuge used to convey sludge to evaluate the efficiency improvement. This analysis was applied to both the original centrifugal model and the design change model, which was a ball-plate rail model, to evaluate the sludge transfer efficiency.

• Korean Chemical Engineering Research
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• v.45 no.4
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• pp.328-334
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• 2007

Chemical heat pump system of 2-propanol/acetone/hydrogen is most suitable to the recovery of waste heat of power plant. various types of 5 wt% Pt-alumina catalysts were prepared for 2-propanol dehydrogenation using sol-gel method. The characteristics and the dehydrogenation reaction rate of each catalyst were investigated. Pt-alumina xerogel catalyst has excellent reaction rate and good durability in comparison with the existing alumina supported Pt catalysts. Pt-alumina aerogel catalyst had the highest reaction rate in all prepared catalysts, but sufficient aging time was necessary to maintain its reaction rate. A potential advantage of the aerogel catalyst is the fact that the high temperature heat treatment is not required. Without heat treatment or with low temperature heat treatment, the Pt-alumina aerogel catalyst has excellent reaction rate as well as durability and this gives us the economic advantage. Alumina xerogel supported Pt catalyst prepared by incipient wetness method showed good reaction rate, and had good mechanical strength. Blank alumina xerogel prepared by sol-gel method can be used for the support of metal catalysts.

• Food Science and Preservation
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• v.20 no.1
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• pp.37-44
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• 2013

To investigate the usability of the bitterns produced during salt manufacture, the characteristics of soybean curds coagulated with bitterns like solar salt bitterns (SSB), dehydrated salt bitterns (DSB), concentrated sea water (CSW) and bitterns produced during the storage of solar salt (BSS) were measured. The Mg contents of all the bitterns were the same, but the Na content of the BSS was 1.0-2.0 times as high as that of the other bitterns. The yield of the soybean curds did not differ with the addition of coagulants, except for the CSW. However, the soybean curds were acquired in large quantities by the DSB and CSW. The mg and Na contents of the soybean curds that were made with the bitterns were higher than those of $MgCl_2$. The heavy metals were below 3 ppm in the curds, especially those produced by the CSW, but Pb was not detected. Among the mechanical characteristics of the soybean curds, their adhesiveness was not affected by the coagulants, but the mechanical hardness of the curds produced by the DSB and CSW was lower. The sensory evaluation showed that the curds that were produced by the bitterns were more highly preferred than those produced by $MgCl_2$. In particular, the soybean curd that was made with the CSW was favored due to its soft texture. The results of this study, particularly the high yield of the curds that showed a soft texture, showed that the bitterns, especially the CSW, could be used safely and economically.

• Proceedings of the Korea Technical Association of the Pulp and Paper Industry Conference
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• 2002.05a
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• pp.15-16
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• 2002

라이너지는 대부분의 원료물질을 고지로부터 얻고 있는 친환경적 상품이 다. 그러나 고지를 원료로 사용함에 따라 많은 문제가 발생하게 된다. 그중 원료와 함께 유입되는 다양한 종류의 오염물질로 인하여 기인되는 스틱키는 강도를 저하시킬 뿐 아니라 얼룩 및 반점을 형성하여 제품의 질을 떨어뜨리 고, 또한 설비를 오염시켜 수명 단축 및 세척에 의한 조업중단 등 생산성 저 하를 가져온다. 이러한 문제는 초지기의 대형화와 고속화, 용수조건의 악화 및 고지 재활용율 증가 등의 이유로 더욱 커지고 있다. 본 논문에서는 라이너지 생산공정의 가운데 지료조성공정의 매크로 스틱 키 정량분석을 통하여 전반적인 분포를 조사하였다. 그 결과 매크로 스틱키 는 스크린과 클리너를 통해 다량 제거되고, 공정상의 기계적 에너지에 의해 더욱 미분화되어 제어가 어려운 마이크로 스틱키로 진행되고 있음을 확인하 였다. 또 지료 분급을 위하여 설치된 플로테이션 설비는 기존의 정선설비인 스크린과 클리너에서 제거되기 어려운 마이크로 스틱키를 제거할 수 있음을 확인하였다. 본 연구에서는 실제 공정의 마이크로 스틱키 정량이 가능한 설비를 제작 하였다. 제작된 설비는 마이크로 스틱키의 정량 뿐만 아니라 환경의 변화에 따른 마이크로 스틱키의 침착성 변화를 볼 수 있도록 하였고, 또한 현장조건 에 적합하도록 다량의 지료분석과 손쉬운 작동이 가능케 하였다. 제작된 마 이크로 스틱키 정량설비를 이용하여 현장 플로테이션 공정을 대상으로 마이 크로 스틱키를 정량한 결과 리젝트의 지료에서 더 많은 량의 마이크로 스틱 키가 존재함을 확인하였다. 이는 소수성의 마이크로 스틱키가 기포와 함께 리젝트로 배출되고 있음을 보여주고 있으며, 또한 3종의 분급된 지료에서 와 이어상에서 탈수된 각각의 백수를 분석함으로써 백수 재활용에 따른 마이크 로 스틱키의 농축현상올 밝혔다. 플로테이션 과정중에 마이크로 스틱키의 거동 파악과 제어를 향상시키기 위하여 MCC를 이용하여 준비된 마이크로 스틱키 모텔물질을 이용하여 실험 실적 부유부상 실험을 실시하였다. 이를 통하여 플로테이션 공정의 마이크로 스틱키 제어 최적화 방안과 고농도의 마이크로 스틱키를 함유한 지료의 처 리를 방안을 검토하였다.

• Journal of Radiation Protection and Research
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• v.25 no.4
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• pp.217-221
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• 2000

Radiotheraphy may be considered as one of the most effective treatments for digestive tumors. This procedure has major side effects, especially in fast growing tissues like intestinal mucosa. For this reason, the morphological changes in mouse jejunal villi after whole body ${\gamma}-irradiation$ were analysed. Four week old ICR male mice were irradiatied with 6.5Gy or 12Gy of whole body ${\gamma}-irradiation$ and were sacrificed 3 days later. Jejunum among intestine were taken for morphology. Samples were carried out dehydration process and sliced sample covered with paraffin was hold on the slide and then light microscopy was observed by Hematoxylin & Eosin staining. villi at both irradiated doses were showed that the length of villi were shortened and thickened and that lumen were expanded in comparison with non-irradiated group. Since willi have an important role in digestion and very sensitive to radiation from this test, it has a role of test parameter for finding radioprotectors as well as evaluating the biological effect by radiaton.

• Analytical Science and Technology
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• v.18 no.3
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• pp.216-223
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• 2005

In this study, several kinds of volatile amines in ambiant air were collected and their concentrations were expected from the calibration curves prepared by standard solutions of 7 amines by the official measuring method prescribed in Japanese Offensive Odor Law. The obtained calibration curves showed a good linearity and the detection limit of trimethyl amine was found to be about 0.033 ppb (0.040 ng) in case of 50 liters air. It means that trimethyl amine could be detected with the concentration of lower than its permitting level at the border line of companies. As typical examples of measuring amines in air, results of investigation of two sewage works and one rendering plant around the capital area indicated that 4 kinds of amines, i.e. methyl amine, dimethyl amine, trimethyl amine and isopropyl amine were detectable and concentrations of trimethyl amine at the primary sedimentation pond and sludge dewatering building of the sewage plant A showed 9.07 ppb and 7.79 ppb respectively, being over the concentration of odor strength 2.5, And the aeration tank, excrement input facility and indoor of maintenance room of excrement process building in the sewage plant B showed 70.0 ppb of dimethyl amine and 2.44 ppb of trimethyl amine.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.36 no.5
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• pp.571-577
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• 2012

In this study, a small movable batch treatment system for dredging soil deposited in a rain water tube is proposed; further, a vacuum silo sorting separation device with a vacuum silo, first-stage sorting separator, and conveyor is designed. The vacuum silo sorting separation device also consists of a storage tank, transferring screw, vacuum gate, screen bar, screen bar cleaner, and vacuum discharging device. In view of the fact that the flow of drawn air in the storage tank is a major factor influencing the sorting separation performance, the optimum shape of the tank is determined by CFD flow analysis. In addition, by using CAE structure analysis, the safety of a storage tank made of boards is examined. The specifications of the vacuum silo sorting separation device are determined by conducting mechanical and dynamic simulations of the driving mechanism of the vacuum silo sorting separation device through 3D-CAD modeling. Following this study, we will design a drum-screen-type second sorter, a decanter-type dehydration device, and waste water tank and pump as a secondary device. Further, on the basis of this design, we will construct a prototype model and carry out a field test.

• Applied Chemistry for Engineering
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• v.17 no.2
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• pp.177-182
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• 2006

In this work, we have prepared organophilic MMT having thermal stability by ion exchange reaction of various aromatic ammonium salts with MMT containing sodium ion. The organic modifiers having alkyl side chains and amine functional group were successfully synthesized by effectively introducing the surfaces of MMT via ion exchange reaction to form organophilic MMTs with a view to improve the reactivity and thermal stability. The WAXD patterns of organophilic MMT showed the more increased gallery spacing by $3.3{\AA}$ than that of the pristine MMT and also the onset of initial decomposition of organophilic MMT was $275^{\circ}C$ as determined by a thermogravimetric analysis. The polyimide (PI) nanocomposite films based on poly(amic acid) and organophilic MMT were prepared by a solution blending followed by cyclodehydration reaction. We have investigated the dispersity of organophilic MMTs in PI matrix by using WAXD and the effect of the organophilic MMT content on the mechanical properties of PI nanocomposite films was studied.

• Journal of the Korea Organic Resources Recycling Association
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• v.8 no.4
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• pp.93-99
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• 2000

Treatment of shaving scrap, a chrome containing solid scrap generated by leather manufacturing process, has been so far depended on mainly incineration, soil landfill and ocean dumping, which give bad impact on environment and cause pollution. Shaving scrap generates from the mechanical work for controlling the final thickness of leather and its main components are collagen protein and pan of chromium compound. For the purpose of reusing this leather waste as resources, researches in connection with collagen fiber recovery, gelable protein recovery and liquid fertilizer is being speedily progressed. In the experiment, shaving scrap went through wet pulverizing treatment by physical and chemical methods. Then, making the leather sheet evenly, it is mixed with natural latex and every kind of binding materials in the container, and the mixtures were passed through experimental hydraulic press machine and applied to Fourdrinier machine respectively. Lastly, a test for fading out physical strength and properties of multiple-purpose of leather-like material was performed on a continuous leather sheet prepared by the experiment. In result, the physical strength and properties of leather-like material showed noticeable differences according to mixing ratio of binding materials, beating methods and the Ends of binding materials selected, and generally tear strength was the weakest property among others. Also, by the pilot scale experiment in sequence, it was possible to manufacture recycled goods made of soft and hard types of leather-like material with various performances.

• 한국신재생에너지학회:학술대회논문집
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• 2011.11a
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• pp.110.2-110.2
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• 2011

바이오가스 생산은 현재 정부에서 추진하고 있는 저탄소 녹색성장으로 인해 더욱 그 가치의 중요성이 부각되고 있다. 스웨덴 Scandinavian Biogas Fuel AB(SBF) 사의 바이오 가스 생산 기술을 이용함으로 소화효율을 개선하고 바이오가스 발생량을 극대화하였다. 전국 403개 공공하수처리시설 중 소화조가 설치된 처리시설은 65 개소이며 이중 57 개소에서 총 64개 소화조를 운영 중이다. 하지만 국내 소화조의 효율은 유입수질 저하, 운영, 관리 미숙으로 인해 전진국의 1/4 수준으로 에너지 이용률이 미미한 편이다. 환경부는 2010년부터 에너지 이용, 생산사용 확대, 추진을 위해 하수처리시설별 이용 가능한 에너지 잠재력의 종류, 양, 지역 내 수요자, 공급자 의 현황 규모 등을 정리해 2012년부터 에너지 이용사업 확대를 추진한다. SBF의 기술을 바탕으로 하수처리시설에서 들어오는 하루 슬러지 $1370m^3$와 음식물쓰레기 180t을 함께 처리하며 바이오가스 생산량을 더욱 늘렸다. 각 $7,000m^3$의 달걀모양(egg shape) 소화조 2개를 운영하며 생 슬러지와 음식물 쓰레기 처리 후 바로 소화조로 투입, 혐기 소화하는 방식이며 슬러지 최종처분방법은 탈수 후 소각된다. 반입되는 생 슬러지의 평균 TS 1.7%, VS 63% 이며 농축 후에는 평균 TS 9%, VS 75% 이다. 또 소화조로 들어가는 음식물 쓰레기는 평균 TS 8%, VS 85% 이며 소화 후 평균 TS 3.6% VS 59% 이다. 그리고 소화조의 pH는 7.3~7.8,유기산의 농도는 150mg/L~350mg/L, 가스발생량은 하루 평균 $26,500Nm^3$이며 소화효율은 평균 67%이다. 혐기성소화는 산소가 없는 무 산소 상태 에서 분해 가능한 유기물을 분해시켜 메탄으로 전환시키고 우리는 현재 이 가스를 소화조 가온에 사용하고, 판매하고 있다. 소화효율을 높이기 위하여 가온과 교반이 행해지는데 가온방식은 직접가온방식(증기주입식)과 간접가온방식(열교환방식)이 있다. 그중 우리는 간접가온방식을 채택하여 소화효율을 높였고 일반중온 혐기소화온도보다 약간 높은 $38^{\circ}C$로 운전한다. 그리고 일반적으로 알려진 교반방식인 가스교반, 기계교반, 이 둘은 병행한 교반이 아닌 독자적인 방법을 이용, 소화조 내의 슬러지가 정체되어 교반되지 않는 부분을 최소화 하였다. 이때 미생물이 투입되기 힘든 소화조 아래 쪽 으로도 고루분포 되어 슬러지를 이용 하게 되고 소화조 상하부의 온도차가 $1^{\circ}C$ 이하로 거의 완벽한 교반상태를 보여 줌 으로써 소화효율을 최대한으로 한다. 더욱이 소화일수 부족으로 인한 전반적 소화효율 저하가 발생하지 않도록 input과 output 조절을 통한 적정소화일수 20~25일을 최대한 맞추어 운전하여 소화조 설계용량의 평균 90%를 활용하고 있다.