In this paper, a numerical study was conducted on the development of HVAC(Heating, Ventilating and Air Conditioning) performance required for a large-scale greenhouse. In order to increase the simulation efficiency, fan model, porous media, and radiator model, etc. provided by Fluent were used based on the part performance analysis such as blowing fans and PTC heaters. Developed simulation method was applied to the decision of fan position to secure the flow uniformity and the determination of the heater specification to maintain the temperature suitable for plant growth. This study is the first step for the development of integrated environmental control system of greenhouse for high-income crop cultivation and the simulation method will be revised after correlation test.
In this paper, numerical simulations were conducted to secure both flow distribution and uniform flow discharge through a wall mount type air sterilizer. In order to increase the reliability of the simulation results where there is no well-known validation case for air sterilizer, mesh sensitivity study was performed under the constraint that y+ set to one for k-w SST turbulent modeling for both the air sterilizer and the fan. The installation of various guides and structures was reviewed in the point of flow distribution and pressure drop inside the sterilizer, and the exhaust pressure conditions were predicted to secure uniform flow discharge at outlets. This study has been done based on the computational analysis during the development stage of the air sterilizer, and the results will be verified through physical testing after production of prototype.
This study analyzed the relationship between the community structure of benthic macroinvertebrates and habitat changes in open estuaries among the sites included in the national estuary monitoring program. The estuary survey was conducted under the “Guidelines for Investigation and Evaluation of Biometric Networks” and classified by sea area, 80 places in the East Sea, 102 places in the South Sea, and 19 places in the West Sea were investigated. In a total of 201 open estuaries, benthic macroinvertebrates were identified with 4 phyla, 9 classes, 41 orders, 139 families, 269 species and 196 species in the East Sea, 182 species in the South Sea, and 90 species in the West Sea. The highest population densities were Insecta in the East Sea, the Malacostraca in the South Sea, and the Annelida in the West Sea. Through SIMPER analysis, species contributing to the similarity of benthic macroinvertebrates communities in each sea area were identified. Some species greatly influenced the similarity of clusters. The benthic community in the East Sea was affected by the salinity, so the contribution rate of freshwater species was high. On the other hand, the benthic communities of the South and West Seas showed species compositions are influenced by the substrate composition. As results, the benthic macroinvertebrate community in Korean estuaries was impacted by salinity and substrate simultaneously, and the close relationship with geographical distance was not observed. The result of this study is expected to be used to respond to environmental changes by identifying and predicting changes in the diversity and distribution of benthic macroinvertebrates in Korea estuaries.
In this study, the analysis of the unsteady viscous flow field using the uRANS equation in a moving mesh was studied. The simulation domain is composed of an overset zone fixed to a propeller and rotating at a constant angular speed and a far zone which is located in the far distance and does not move. Each zone is composed of a polyhedral meshes for the accurate and robust gradient calculation in addition to the reduction of computation time. Simulation technique was applied to the aerodynamic analysis of the 5-inch propeller and compared with those of the MRF and the thrust test. The thrust predicted by the moving mesh showed good correlation with the MRF result within 0.5% difference, but the torque showed a tendency to under-prediction by about 10% compared to the MRF. In the future, we plan to further validate the numerical analysis technique using the moving mesh by applying it to the configurations in which precise test results exist.
압출성형 결과 최근 관심이 많은 구증구포 흑삼에 함유 되는 진세노사이드인 Rg2, Rg5 등의 함량이 바렐온도가 높은 조건에서 매우 많이 증가되는 결과를 볼 수 있다 기존의 연구는 실험실 수준의 압출 성형기를 사용하였으나 산업화가 가능한 pilot-scale 설비를 사용하여 scale-up 공정의 가능성을 확인하였다. 또한 preconditioner를 활용하여 압출성형 전에 수증기에 의한 수화 및 열처리를 통해서 보다 효율적인 인삼 가공공정이 가능한 공정으로 운영하였다. 압출성형 결과 최근 관심이 많은 구증구포 흑삼에 함유되는 진세노사이드인 Rg2, Rg5 등의 함량이 바렐온도가 높은 조건에서 매우 많이 증가되는 결과를 볼 수 있다. 이는 pilot scale twin-screw extruder 설비를 활용한 공정이 인삼의 가공 공정으로 산업화에 유용하게 사용될 수 있는 결과라 사료된다.
Spare part management is very important to products that have large number of parts and long lifecycle such as automobile and aircraft. Supply chain must support immediate procurement for repair. However, it is not easy to handle spare parts efficiently due to huge stock keeping units. Qualified forecasting is the basis for the supply chain to achieve the goal. In this paper, we propose an agent based modeling approach that can deal with various factors simultaneously without mathematical modeling. Simulation results show that the proposed method is reasonable to describe demand generation process, and consequently, to forecast demand of spare parts in long-term perspective.
The present note provides an overview of the three succeeding scientific papers, which gives an insight about the multidisciplinary studies and opinion on Biodiversity. These three papers are based on the seminar series of biodiversity organized by the department of life science, Hanyang University during 2011~2013.
본 연구는 DDGS의 첨가가 거세한우의 비육성적, 도체특성 및 지방산조성에 미치는 영향을 조사하기 위해서 실시되었다. 평균 28.2개월령 (평균 체중 747.1±62.8㎏)의 거세한우 44두를 대조구, 시험1구 (DDGS 15% 첨가구) 및 시험2구 (DDGS 30% 첨가구)에 각각 15, 14 및 15두씩 배치하여 84일간 사양시험을 실시하였다. 일당증체량은 처리구별 유의적인 차이가 나타나지 않았다. 사료요구율은 시험1구와 시험2구가 대조구에 비하여 각각 9.3%과 17.1% 낮게 나타났다. 도체성적의 경우 등지방두께와 등심단면적은 처리구별 차이가 나타나지 않았다. 처리구별 육질등급별 출현율은 1++등급 출현율은 시험1구 (42.9%)에서 가장 높았고, 시험2구 (26.7%)에서 가장 낮게 나타났다. 도체등심의 지방산 조성은 불포화지방산 함량은 시험1구가 시험2구에 비하여 유의적 (P<0.05)으로 높게 나타났으며, C18:2 (linoleic acid) 및 다가 불포화지방산은 시험1구 및 시험2구에서 유의하게 (P<0.05) 높게 나타났다. 이상과 같은 결과를 종합해 보면, 거세한우의 비육후기에 DDGS 15% 급여한 시험1구에서 사료요구율, 육질등급 및 불포화지방산 함량 증가에 효과적인 것으로 나타났다.
CONWIP is robust and efficient for various type of operating system, such as series, parallel, and assembly systems. Especially, assembly system would be controlled couple of modified CONWIP system. In the following paper, we developed Critical Path CONWIP system that gives signal to sub-line from a station of critical path then, compared with m-conwip, discrete-card-buffer CONWIP. 2 representative asymmetric assembly system models are used to compare each control system. As a result, critical path CONWIP holds less whole work-in-process with similar output. It can decrease total cost and WIP for high holding cost assembly system
본 연구는 플라스틱하우스 수박 재배 시 육묘 포트종류와 그 정식 방법이 정식 후 생육 및 과실 특성에 미치는 영향을 알아보기 위해 수행하였다. 잎의 수, 면적 및 광합성률, 초장, 생체중량 모두 정식 후 시간이 경과하면서 관행포트 묘에 비해 이중플라스틱포트 묘에서 우수한 경향을 나타내었다. 수확과의 과고, 과폭 및 과중도 이중플라스틱포트 묘에서 다른 포트 묘에 비해 다소 큰 경향이었다. 과피두께는 사각형피트포트 묘에서 가장 얇았고 관행포트 묘에서 가장 두꺼웠으며, 배꼽 직경은 과피두께 결과와 반대의 경향을 나타내었다. 그리고 이중플라스틱포트 묘의 정식 깊이에 따른 초기 생육은 포트 높이의 2/3 정도에서 가장 우수하였다.
The ammonia in ambient were sampled by high efficiency diffusion scrubber (HEDS) and analyzed by IC. Ammonia showed high linearity (R²>0.999) of the calibration curve and good repeatability (RSD<5%). The detection limit of Ammonia was about 0.05 ppbv. Average concentration of Ammonia was 12.7 ppbv, Instantaneous maximum concentration was 83.4 ppbv. Continuous sampling method is proper to monitor ammonia which is the odor material instantaneously increased mainly affected by meteorological condition. The sampling and analysis process can be automated and performed in real-time by continuous sampling of HEDS-IC system.
목적:이 연구는 노인전문병원에 입원한 환자들의 일상생활활동과 관련된 요인을 알아보고자 하였다.
연구방법:연구대상은 전국 8개 노인전문병원에 입원한 환자 1,001명을 대상으로 하였다. 일상생활활동능력 및 그와 관련된 요인은 RAI(resident assessment instrument) Long-Term Care Facility version 한글판을 사용하여 조사하였다. 조사기간은 2003년 1월 26일에서 3월 8일까지였다.
결과:노인전문병원에 입원한 환자들의 79.9%가 신경계 질환을 갖고 있었다. 일상생활활동과 관련된 요인은 인지 기능, 수의운동, 균형능력, 시각기능 및 신경계 질환의 유무였고, R-square 값은 .66이었다.
결론:이 연구결과를 통해 노인전문병원에서 신경계 질환을 갖고 있는 환자가 가장 많이 입원하고 있었으며, 일상생활활동과 관련된 요인은 인지기능, 수의운동, 균형능력, 시각 기능임을 알 수 있었다. 그러므로 노인전문병원에서 신경계 질환을 대상으로 하는 재활치료 프로그램이 강화되어야 할 것이다. 그 중 작업치료는 다양한 신체기능 상태를 고려하여 일상생활활동 훈련을 시행하는 보건전문영역이므로 그 역할이 확대되어야 할 것으로 생각된다.