• Nuclear Engineering and Technology
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• 제7권1호
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• pp.53-68
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• 1975

The world's nuclear powered ships have been reviewed mainly based on development of the marine nuclear reactor and the present trends of nuclear warships and merchant ships in the world. In particular, emphasis was on the four nonmilitary nuclear ships, Russian Ice breaker Lenin, American Cargo-passenger ship Savannah, German Ore carrier Otto Hahn, and Japanese Cargo ship Mutsu. They are the only civilian nuclear ships which have entered service at the present time in the world. The nuclear fleets in United States, United Kingdom, Soviet, and France were described in view of historical development and the present stock of the nuclear ships. The present projects and the future trends for the nuclear merchant ships in the main shipbuilding countries have been also discussed. The nuclear fission and reactor were briefly discussed in the beginning of this article.

• Nuclear Engineering and Technology
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• 제56권1호
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• pp.275-282
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• 2024

Lead bismuth eutectic (LBE) is used as coolant for MicroURANUS, a small marine nuclear power plant, and this coolant is transported in the plant by an electromagnetic pump. Given the considerable heat generated by the electromagnetic pump, the cooling of the pump is essential. This study compared air cooling and water-cooling methods and found that the maximum temperatures during air and water cooling were 640 K and 372 K, respectively. These findings were utilized to design an electromagnetic pump with water-cooling. The maximum temperature of the pump was lower than the boiling point of water; thus, the pump did not require a separate pressurization. Consequently, the resistance problem of the coil and the deformation problem of the material caused by generated heat can be solved through water-cooling.

• Journal of Advanced Marine Engineering and Technology
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• 제10권1호
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• pp.74-84
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• 1986

Ejectors, having no moving, lubricating and leaking parats, are widely used as marine pumps because of its high working confidence. For instance, uses in ships are stripping in crude oil tank, bilge discharge in engine room, ballast water pumping on are carrier, and brine discharge from fresh water generator. And it is also used as cooling water recirculating pump in boiling water type nuclear reactor and deep-well pump. It is not easy to determine the optimal dimension for designing each ejector agreed with its suggested performance condition, because complicated calculations must be repeated to obtain the maximum efficiency affected by flowrate ratio, head ratio, area ratio and so on. Therefore, it is considered that the CAD (Computer-Aided Design) for ejector is a powerful method for design according to the individual design condition. In this paper, a computer program for water ejector design is developed based on the previous paper on theoretical analysis and experimental results for water ejector. And from the theoretical approach, an equation for the working limit and an equation for determing the shape of throat are obtained. The validity of the present computer program is sufficiently confirmed through the comparison of the computed results with the main dimension of the previous manufactured water ejector. This program will be easily developed as the CAD for various kinds of ejectors, including steam ejector.

• Journal of Industrial and Engineering Chemistry
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• 제68권
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• pp.267-273
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• 2018

Hydrothermal liquefaction of Chlorella vulgaris feedstock containing 80% (w/w) water was conducted in a batch reactor as a function of temperature (300, 325 and $350^{\circ}C$) and reaction times (5, 10 and 30 min). The biocrude yield, elemental composition and higher heating value obtained for various reaction conditions helped to predict the optimum conditions for maximizing energy recovery. To optimize the recovery of inorganic nutrients, we further investigated the effect of reaction conditions on the ammonium ($NH_4{^+}$), phosphate ($PO_4{^{3-}}$), nitrate ($NO_3{^-}$) and nitrite ($NO_2{^-}$) concentrations in the aqueous phase. A maximum energy recovery of 78% was obtained at $350^{\circ}C$ and 5 min, with a high energy density of 34.3 MJ/kg and lower contents of oxygen. For the recovery of inorganic nutrients, shorter reaction times achieved higher phosphorus recovery, with maximum recovery being 53% at $350^{\circ}C$ and 5 min. Our results indicate that the reaction condition of $350^{\circ}C$ for 5 min was optimal for maximizing energy recovery with improved quality, at the same time achieving a high phosphorus recovery.

• 한국환경기술학회지
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• 제19권6호
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• pp.550-555
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• 2018

국제 해사기구 (IMO)에서 MARPOL 73/78은 조문과 여섯 개의 부속서로 구성되어 있다. Annex IV는 선박의 하수를 규제한다. 2012년 제 64회 결의안에서 선박에서 배출되는 하수 중 영양염류를 제거하도록 규제하였다. 2014년 해양수산부의 지원으로 영양염류를 제거 할 수 있는 대용량 폐수처리 장치를 개발하였다. Sequence Batch Reactor (SBR)와 Membrane Bio Reactor (MBR)를 결합한 새로운 공정이 개발되었다. 현존하는 SBR 공정의 사이클에서는 침전을 제외하고 통기 및 교반만을 사용하였고, 상기 막은 처리 된 물을 배출 시키는데 사용하였다. 본 연구에서는 MACROGEN 사의 NGS 분석 기술을 이용하여 Bench 규모 폐수처리 설비를 이용한 하수처리장 원수를 처리하기 위한 최적 운전조건에서 폭기조 내 미생물의 우점종을 분석하였다. 그 결과 Bacteroidetes는 호기성 박테리아의 27.1 %를 차지했으며 Gammaproteobacteria는 혐기성 박테리아의 16.8 %를 차지하였다. Operational taxonomic unit ratio에 Others 항목이 차지하는 비율도 상당하다고 볼 수 있는데 기존의 오수처리를 위해 필요했던 미생물 외에 아직 NCBI (National center for Biotechnology Information)에 등록되지 않은 미생물일 가능성이 있어 추후 연구가 필요하다고 판단된다.

• Journal of Advanced Marine Engineering and Technology
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• 제39권6호
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• pp.633-641
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• 2015

선박, 발전소, 석유화학 등의 분야에서 운전되고 있는 많은 프로세스들은 강한 비선형성을 보일 뿐만 아니라 동시에 시변 특성도 가지고 있다. 이런 프로세스에 기존의 고정-파라미터 PID 제어기를 적용하면 성능이 나빠지고 경우에 따라서는 불안정해질 수도 있다. 따라서 본 연구에서는 복잡한 프로세스를 제어하기 위한 비선형 PID 제어기를 제안한다. 제안되는 제어기의 이득은 오차와 오차의 변화율의 비선형 함수로 기술되며, 사용자 파라미터들은 ITAE를 최소로 하는 관점에서 유전알고리즘으로 동조된다. 제안된 방법은 열분해반응 또는 촉매를 이용한 고분자합성에 널리 사용되는 연속 교반탱크반응기를 대상으로 시뮬레이션을 실시하며, 그 유효성을 보이기 위해 다른 두 비선형/적응 제어법과 비교한다.

• Journal of Advanced Marine Engineering and Technology
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• 제27권5호
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• pp.657-665
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• 2003

Combined De-NOx Process in which $NH_3$ SCR (Selective Catalytic Reduction) and non-thermal Plasma Process are simultaneously used, has been investigated with a pilot test facility. The pilot test facility treats the combustion flue gases exhausted from a diesel engine that generates 240 kW of electrical power. Test results show that up to 80 % of NOx (NO and NO2) can be removed at 100 - $200^{\circ}C$. None of conventional De-NOx techniques works under such low temperature range. In addition to NOx. the Pilot test results show that soot can be simultaneously treated with the present non-thermal plasma technique. The present pilot test shows that the electrical power consumption to operate the non-thermal plasma reactor is equivalent to 3 - 4 % of the electrical power generated by the diesel engine.

• Journal of Advanced Marine Engineering and Technology
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• 제27권6호
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• pp.790-796
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• 2003

As a fluid machinery for piping liquid in the reactor cooling system, multi-stage centrifugal pump requires the structural dynamic stability against external dynamic excitation. This paper is concerned with the finite element analysis of its eigen behavior and seismic response to RRS(Required Response Spectrum) curves in the case of SSE (Safe Shutdown Earthquake). Through the finite element analysis, the major vibration characteristics of multi-stage centrifugal pump(MSCP) are investigated and seismic qualification based on the IEEE codes is executed. The numerical results show that the MSCP used in this study has enough seismic strength.

• Journal of Microbiology and Biotechnology
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• 제12권3호
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• pp.503-507
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• 2002

Chitosan oligosaccharides (COSs) were prepared and fractionated into three groups of COS [a high molecular weight COS (HMWCOS), medium molecular weight COS (LMWCOS), and low molecular weight COS (LMWCOS)] according to their molecular weight, using an ultrafiltration membrane enzymatic bioreactor designed earlier [8]. Antitumor activity of these COSs was then examined against Sarcoma 180 solid (S180) or Uterine cervix carcinoma No. 14 (Ul4) tumor cell-bearing mice. Among these COSs, MMWCOS with molecular weight range from 1.5 to 5.5 kDa effectively inhibited the growth of both tumor cells in the mice. In addition, the administration of MMWCOS resulted in increased thymus weight among lymphoid organs. The mice treated with MMWCOS showed improved survival rate and larger number of survivors after 40 days of feeding. The most effective of MMWCOS far antitumor activity in the S180- or U14-bearing mice was 20 mg/kg/day or more.

• Journal of Advanced Marine Engineering and Technology
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• 제40권2호
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• pp.112-119
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• 2016

Many studies have been conducted on the performance of a passive autocatalytic recombiner (PAR), but not many have focused on the locations where the PAR is installed. During a severe accident in a nuclear reactor containment, a large amount of hydrogen gas can be produced and released into the containment, leading to hydrogen deflagration or a detonation. A PAR is a hydrogen mitigation method that is widely implemented in current and advanced light water reactors. Therefore, for this study, a PAR was installed at different locations in order to investigate the difference in hydrogen reduction rate. The results indicate that the hydrogen reduction rate of a PAR is proportional to the distance between the hydrogen induction location and the bottom wall.