• 한국환경보건학회지
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• 제6권1호
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• pp.1-9
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• 1979

An experimental study was carried out to develop a rural type toilet of which the effluent could not transmit parasitic diseases at a village in Kangwon Province, Korea, during the period of January through December 1978, A drum tank (dia. 57cm$\times$90cm) and a cement tank (100cm$\times$100cm$\times$100cm) were filled with human excreta collected from toilets of the villages (the ratio of feces to urine was estimated approximately 1: 5) at once and three threecompartment toilets were constructed and used by people. pH, temperatures and viability of parasitic eggs were examined with the content of toilets. Rusults are summarized as follows: 1. pH increased from 7.0 at the beginning of experiment to 7.5 or 8.0 after 4 months of storage in drum tank as well as in cement tank and so did from 7.0~7.5 in the first tank to 8.0~8.5 in the third tank of all three-compartment toilets. 2. Temperatures of content at middle part of toilets in January through March ranged from 2 to 6$\circ$C which were 2-4$\circ$C higher than those of air, and those of lower part were again 1~2$\circ$C higher than of middle part. but temperatures of air, at middle part andat lower part in April were 14$\circ$C, 9~10$\circ$C and 8~9$\circ$C respectively, in July 29$\circ$C, 20~21$\circ$C and 19~20$\circ$C respe ctively and in October 17$\circ$C, 14$\circ$C and 14~13$\circ$C respectively. 3. All the parasitic eggs were degenerated about 4 months after filling drum tank with human excreta on 10th April while 10% of eggs were degenerated on 15th May, and all the eggs were degenerated about 4 months after filling cement tank on 24th August while about 10% were degenerated on 11th September and 20% on 4th October. 4. Degeneration rates of eggs were only 5~15% at 5cm below surface in the first tanks of three-compartment toilets while 45~65% at 50cm below, and concentration rates of eggs in second tanks were 8~12% of those in first tanks and only a few eggs were found in third tank but all of them were degenerated. Specific gravity of liquid of 1.022~1.024 in second tanks was not enough for overflowing eggs into third tanks.

• KSBB Journal
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• 제4권3호
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• pp.221-228
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• 1989

각종 섬유질 효소당화반응조내의 현탁액 혼합교반 양상이 효소당화에 미치는 영향을 검토하기 위하여 3종의 대표적인 bioreactor;vertical impeller type bioreactor-(VITB), horizonatl paddle type bioreactor(TDTB)를 제작하여 그 효용성을 비교 검토하였다. 최적 교반강도는 impel-ler나 paddle로 현탁핵을 교반하는 VITB와 HPTB가 각각 100rpm, 그리고 통자체를 회전시켜 교반하는 TDTB가 200rpm이었으며 TDTB에 부착된 baffle의 형태 및 크기는 큰 영향을 주지 않았다. 또한 VITB나 TDTB의 경우 과다한 교반은 효소의 실활을 유발시켜 오히려 섬유소당화를 저해하였다. 3종의 bioreactor의 최적 교반조건에서의 당화효율을 비교한 결과 VITB가 가장 높았으며 특히 고농도 섬유소 당화시 가장 높은 당화효율을 보여, 가장 효율적인 교반양상을 나타내는 것으로 보인다. 이로 미루어 impeller나 paddle의 물리적 충격에 의한 현탁액의 cellulose network를 파괴시키는 효소반응기가 단순히 교반혼합하는 반응기에 비하여 우수한 결과를 줌을 알 수 있었다. 반면 주어진 양의 당을 생산하는데 소요되는 동력소모를 검토한 결과 TDTB가 VITB에 비하여 다소 낮았으나 고농도의 경우는 급속히 증가되었다. 적절한 bioreactor의 선정에는 기질의 가격, 당화수율, 고농도 당화, 그리고 반응기의 scale-up의 용이성등이 종합적으로 검토되어져야 할 것이다.

• International Journal of Aerospace System Engineering
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• 제1권1호
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• pp.16-20
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• 2014

Recently, various kinds of study on light weight structure are performing in the world. The Al honeycomb sandwich structural type adopt for improvement of lightness and structural stability to major part structure of aircraft or spacecraft. Adhesion badness properties of adhesive and adhesion properties of fillet mainly studied about al honeycomb structure. But study for adhesive properties of sandwich construction with surface treatment of Aluminum alloy barely performed. In this study, adhesive film was used between Al and honeycomb core of honeycomb panel[1]. The study for adhesive properties of sandwich construction with surface treatment of AA 5052 skin was performed.

• Journal of Advanced Marine Engineering and Technology
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• 제33권1호
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• pp.90-96
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• 2009

Injection molding process is one of the most important methods to produce plastic parts with high efficiency and low cost. Today, injection molded parts have been increased dramatically the demand for high strength and quality applications. This report investigates that the optimum injection molding condition for minimum of shrinkage. Molding shrinkage is occurred by several reasons such as thermal shrinkage, a hardening process and compressibility. This report concentrate on shrinkage by a hardening process. As Change a holding pressure and holding time, checked deflections of X, Y, Z directions by shrinkage based on same condition. In conclusion, it was found that holding pressure is stronger and holding time is longer, the deflection by shrinkage is smaller because injection molding needs enough time for cooling and high density. The FEM Simulation CAE tool. Moldflow, is used for the analysis of injection molding process.

• 수산해양기술연구
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• 제35권1호
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• pp.65-76
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• 1999

Our status of off-shore stow-net fishery is in face with many difficult problems; the lack of fisherman by evading the 3-D occupation, the safety accident by unskilled crew and old type fishing system. In order to solve those problems, it is necessary to save the man power and ensure the safety of fishing work by the effective utilization of power and automatization of fishing gear system. This is consists of the side drum driven by main engine, the net hauler, the bow and stern capstan, jib crane etc. Therefore, we suggest the design on unification of power device of fishing gear system as follows; (1) fishing system by uni-hydraulic power and (2) fishing system by electric motor and electro-hydraulic power.

• 한국농업기계학회:학술대회논문집
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• 한국농업기계학회 1993년도 Proceedings of International Conference for Agricultural Machinery and Process Engineering
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• pp.877-885
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• 1993

Three types of solar grain dryers, namely , the solar grain bin dryer, the solar greenhouse rotary drum dryer and small scale solar green house tray dryer, have been tested. The results showed that each type of solar grain dryer has its feature. These solar drying units have three main advantages : (1) Required commercial energy to remove 1Kg moist from rough rice is only 5.3% to 15.8% of the energy consumed by common heated dryer : 2) The area of solar drying system is only about 10% of the area of the sunny ground to give equal drying capacity ; (3) There are good drying quality in the moisture uniform , germination percentage, and grain color.

• Journal of Magnetics
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• 제5권2호
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• pp.59-64
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• 2000

A drum type of high gradient magnetic separator was designed and optimized by computer simulations. The magnetic separator consists of high performance rare earth $(Nd_2Fe_14B)$ permanent magnets and magnetic yokes of extremely low carbon steel interconnecting the permanent magnets. Magnetic circuits of the separator were simulated for the aim of the least cost, highest magnetic strength and most efficient function by using specialized S/W (Vector Field Program) employing the Finite Element Method. The magnetic flux density was provided to be strong enough to collect the invisible fine metal particles from the surface of hot rolled steel plate with the efficiency of almost 95%.

• 대한전기학회논문지:전력기술부문A
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• 제48권9호
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• pp.1119-1125
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• 1999

In this paper, a decentralized multilevel-adaptive controller for a boiler-turbine system is designed by using multiple model adaptive method. It is applied to the drum type boiler-turbine system which is simplified from Boryung T/P #1,2 model. A linearlized model is decomposed into three subsystems by means of linear transformation. Then the DMC based on such subsystem is designed and a Multiple Model Adaptive Control(MMAC) scheme is applied for the purpose of the good tracking to variable load demands of the thermal power plant. The good performance of the designed controller is shown by simulations in various conditions that have the large step and ramp change of power demamd.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 1992년도 한국자동제어학술회의논문집(국내학술편); KOEX, Seoul; 19-21 Oct. 1992
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• pp.880-886
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• 1992

There has been continuous effort to achieve total automation of the power plants. But due to complexity, nonlinearities and time-varying properties of the system, no success has been reported if conventional and/or modern control theories are applied. In spite of this, the start-up and shutdown operations are successfully performed by skilled human operators who are able to utilize a great wealth of knowledge and past experiences. In this paper, in order to automate the shutdown operation of power plants, it is proposed that the operation be performed by a more efficient method than the current used, through dividing the total process into several subprocesses, introducing checkpoints, and using fuzzy logic. For this, fuzzy logic controllers and fuzzy decision-makers are designed and the validity is shown by simulation via a set of piecewise continuous shutdown models.

• Nuclear Engineering and Technology
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• 제50권4호
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• pp.619-626
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• 2018

Most publications confirm that an ecological interface is a very efficient tool to supporting operators in recognition of complex and unusual situations and in decision-making. The present article describes the experience of implementation of an ecological interface concept for visualization of material balance in a drum separator of RBMK-type NPPs. Functional analysis of the domain area was carried out and revealed main factors and contributors to the balance. The proposed ecological display was designed to facilitate execution of the most complicated cognitive operations, such as comparison, summarizing, prediction, etc. The experimental series carried out at NPPs demonstrated considerable reduction of operators' mental load, time of reaction, and error rate.