• 한국환경과학회지
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• 제14권9호
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• pp.827-835
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• 2005

A three-dimensional ecological model (EMT -3D) was applied to Nonylphenol in Tokyo Bay. EMT -3D was calibrated with data obtained in the study area. The simulated results of dissolved Nonylphenol were in good agreement with the observed values, with a correlation coefficient(R) of 0.7707 and a coefficient of determination (R2) of 0.5940. The results of sensitivity analysis showed that biodegradation rate and bioconcentration factor are most important factors for dissolved Nonylphenol and Nonylphenol in phytoplankton, respectively. In the case of Nonylphenol in particulate organic carbon, biodegradation rate and partition coefficient were important factors. Therefore, the parameters must be carefully considered in the modeling. The mass balance results showed that standing stocks of Nonylphenol in water, in particulate organic carbon and in phytoplankton are $8.60\times 10^5\;g,\;2.19\times 10^2\;g\;and\;3.78\times 10^0\;g$ respectively. With respect to the flux of dissolved Nonylphenol, biodegradation in the water column, effluent to the open sea and partition to particulate organic carbon were $6.02\times10^3\;g/day,\;6.02\times10^2\;g/day\;and\;1.02\times10^1\;g/day$, respectively.

• 공업화학
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• 제2권4호
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• pp.393-398
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• 1991

실제 실험 시간에 따른 시료의 무게변화와 생성가스의 조성 측정을 동시에 진행할 수 있는 실험실 규모의 장치를 칸 발란스를 이용하여 제작하였다. 급속 가열이 가능하도록 텅스텐 할로겐 등을 이용한 복사가열 방식을 채택하였고 시료 접시는 복사열을 충분히 흡수하도록 흑연을 사용하였다. 석탄가스화 실험조건에서 이 흑연이 반응기체와 반응하는 것을 막기위하여 실리콘나이트로 코팅하였고, 시료접시 바로 밑에 위치한 열전쌍에도 같은 방식으로 제작된 흑연 모자를 씌워 복사열 흡수능력이 서로 다른 흑연(시료접시)과 금속체(열전쌍) 사이에서 생길 수 있는 온도 측정의 오차를 최소화 하도록 하였다. 이 장치를 사용한 결과 상온에서 섭씨 800도까지 3 분 이내에 온도상승이 가능하였으며 시료 접시의 무게변화없이 실험중 석탄 시료의 무게 변화와 가스조성을 동시에 측정할 수 있었다.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 1990년도 한국자동제어학술회의논문집(국제학술편); KOEX, Seoul; 26-27 Oct. 1990
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• pp.1361-1364
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• 1990

In order to tackle global environmental problems such as destruction of the ozone layer or climatic changes due to atmospheric temperature increase, the acquisition of plentiful and precise data is necessary. Therefore, a means of conducting long-lasting high-resolution measurements over broad areas is required. A feasibility study has been made on a high altitude (20km), super-pressured helium-filled PLTA (Powered Ligher-than-Air) vehicle as an ideal platform for environmental observation. It has a long service life and carries a larger payload than an artificial satellite. This PLTA platform uses an electric propulsion system to maintain position in space against wind currents. The thruster is driven by solar power acquired from solar cells. For night use, solar energy is stored in regenerative fuel cells. This study focuses on energy balance and structural analysis of the hull and platform. The platform is capable of conducting high resolution remote sensing as well as having the capability to serve as a telecommunications relay. The platform could replace a number of ground-based telecommunications relay facilities, guaranteeing sufficient radio frequency intensity to secure good quality telecommunication transmittal. The altitude at which the platform resides has the lowest wind flow in the lower stratosphere, and permits viewing from the ground within a 1,000km range. Because this altitude is much lower than that required of an artificial satellite, the measuring resolution is a couple of thousand times higher than with artificial satellites. The platform can also be used to chase typhoons and observe them from their sources in tropical regions.

• 열처리공학회지
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• 제13권5호
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• pp.346-354
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• 2000

Effect of Nb addition on the phase transformation behavior was studied through continuous cooling transformation tests after reheating(reheating CCT) and deforming(deforming CCT) the 0.07%C-1.3%Mn-0.015%Ti-(0~0.08)% Nb steels. Transformation temperatures for deforming CCT were lower than those for reheating CCT, and the critical cooling rate for bainite transformation during deforming CCT was lower than that during reheating CCT. These enhanced hardenability for deforming CCT was considered to come from the sufficient solid solution of Nb in austenite during high temperature reheating before deformation. With Nb addition, the phase transformation temperature decreased, the bainite formation was enhanced, and the hardness of steel increased. Furthermore, these phenomena were more remarkable for deforming CCT than for reheating CCT. From the results, Nb-Ti bearing low carbon steel was considered to be a very favorable alloy system with good strength/toughness balance by recrystallization control rolling process.

• Journal of Biosystems Engineering
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• 제37권2호
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• pp.82-89
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• 2012

Purpose: The simulation model of a pneumatic conveying drying (PCD) for sawdust was developed and verified with the experiments. Method: The thermal behavior and mass transfer of a PCD were modeled and investigated by comparing the experimental results given by a reference (Kamei et al. 1952) to validate the model. Momentum, energy and mass balance, one dimensional first order ordinary differential equations, were coded and solved into Matlab V. 7.1.0 (2009). Results: The simulation results showed that the moisture content reduced from 194% to 40% (dry basis), air temperature decreased from $512^{\circ}C$ to $128^{\circ}C$ with the particle residence time of 0.7 seconds. The statistical indicators, root mean square error and R-squared, were calculated to be 0.079, and 0.998, respectively, between the measured and predicted values of moisture content. The relative error between the measured and predicted values of the final pressured drop, air temperature, and air velocity were only 8.96%, 0.39% and 1.05% respectively. Conclusions: The predicted moisture content, final temperature, and pressure drop values were in good agreement with the experimental results. The developed model can be used for design and estimation of PCD system for drying of wood dust particles.

• Spatial Information Research
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• 제14권1호
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• pp.115-128
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• 2006

본 연구의 목적은 GIS를 이용하여 공간자료 분석을 통한 포항지역의 지하수 개발적지 선정 및 검증을 하는 것이다 이를 위해 본 연구에서는 물수지, 토지이용, 임상도, 토양분포, 지형고도, 경사, 수문지질 및 선구조 등을 분석하였다. 그리고 이러한 분석 자료 및 GIS 공간분석기법을 이용하여 지하수 산출성 표본자료와 상관 분석하여 수문지질 특성평가를 실시하여 수문지질특성에 따른 지하수 산출 특성을 도출하였다. 이러한 결과를 바탕으로, 포항시의 지하수 개발 적지 선정을 위한 지하수 잠재 가능성도를 작성하였고, 이를 지하수 산출량 자료와 비교 검증을 하였다. 검증 결과 지하수 개발 적지 분석 결과와 지하수 산출량 자료와의 관련성이 높게 나타났다. 이러한 지하수 개발 적지 선정 결과는 지하수 개발에 관련된 관리에 사용될 수 있다.

• 한국식품영양과학회지
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• 제35권8호
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• pp.1106-1114
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• 2006

Good health and longevity are the goal of human beings. Dietary treatment for the improvement of health and chronic diseases therapy has been occupied an important position in Oriental and Western medicine. In this paper, the viewpoints of dietary treatment in Oriental and Western medicine were compared. The principle of Yin-Yang and five elements, as a standing rule that establishes the theory of Oriental medicine and origin of the oriental philosophy, it provides the based of the Oriental medicine's outlook of the world. The principles of dietary treatment in Oriental medicine was reasonable combination of food, balance of Oh-Mi and temperance of food. Nutritional therapy in Oriental medicine has done the phase of Bian Zheng by individual characteristics. The theory of Yin-Yang and five elements, Ki-Mi, Sasang Constitution Medicine and Kyi-Kyung were obviously recognized the theory of nutrition therapeutics in Oriental medicine. In Western medicine, dietary treatment supplies individuals with a recipe of calorie and specific nutrients. The Food Exchange System was very convenient way of practice in nutrition therapy. But each of dietary treatment in Oriental and Western nutrition has strong and week points. So we need to study enough materials to treatment of Oriental nutrition and Western nutrition for the improvement of health and chronic diseases therapy.

• 설비공학논문집
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• 제15권3호
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• pp.177-186
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• 2003

In the present study, the flow characteristics of developing turbulent flows are investigated at the exit region of a square cross-sectional 180" curved duct with dimensions of 40mm$\times$40mm$\times$4000mm (height $\times$ width $\times$length). Smoke particles produced from mosquito coils were used as seed particles for the LDV measurement. Experiments were carried out to measure axial velocity profiles, shear stress distributions and entrance lengths by using an LDV system and Rotating Machinery Resolver RMR with PHASE software. Experimental results clearly show that the time-averaged Reynolds number does not affect oscillatory flow characteristics because the turbulent components tend to balance the oscillatory components in the fully developed flow region. Also, the velocity profiles are in good agreement with 1/7power law such as the results of steady turbulent flows. The turbulent intensity linearly increases along the walls and is slightly higher, especially in the period of deceleration. On the other hand, the LDV measurements show that shear stress values in slightly higher in the period of deceleration due to the flow characteristics in the exit region. The entrance length where flows become stable appears at the point that is 40 times the length of hydraulic diameter.eter.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제17권1호
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• pp.97-119
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• 2023

The number of industrial Internet of Things (IoT) users is increasing rapidly. Lightweight block ciphers have started to be used to protect the privacy of users. Hardware-oriented security design should fully consider the use of fewer hardware devices when the function is fully realized. Thus, this paper designs a lightweight block cipher IIoTBC for industrial IoT security. IIoTBC system structure is variable and flexibly adapts to nodes with different security requirements. This paper proposes a 4×4 S-box that achieves a good balance between area overhead and cryptographic properties. In addition, this paper proposes a preprocessing method for 4×4 S-box logic gate expressions, which makes it easier to obtain better area, running time, and power data in ASIC implementation. Applying it to 14 classic lightweight block cipher S-boxes, the results show that is feasible. A series of performance tests and security evaluations were performed on the IIoTBC. As shown by experiments and data comparisons, IIoTBC is compact and secure in industrial IoT sensor nodes. Finally, IIoTBC has been implemented on a temperature state acquisition platform to simulate encrypted transmission of temperature in an industrial environment.

• Nuclear Engineering and Technology
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• 제56권3호
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• pp.1002-1012
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• 2024

To remove insoluble fission products, which could possibly cause reactor instability and significantly reduce heat transfer efficiency from primary system of molten salt reactor, a helium bubbling method is employed into a passive molten salt fast reactor. In this regard, two-phase flow behavior of molten salt and helium bubbles was investigated experimentally because the helium bubbles highly affect the circulation performance of working fluid owing to an additional drag force. As the helium flow rate is controlled, the change of key thermal-hydraulic parameters was analyzed through a two-phase experiment. Simultaneously, to assess the applicability of numerical model for the analysis of two-phase flow behavior, the numerical calculation was performed using the OpenFOAM 9.0 code. The accuracy of the numerical analysis code was evaluated by comparing it with the experimental data. Generally, numerical results showed a good agreement with the experiment. However, at the high helium injection rates, the prediction capability for void fraction of helium bubbles was relatively low. This study suggests that the multiphaseEulerFoam solver in OpenFOAM code is effective for predicting the helium bubbling but there exists a room for further improvement by incorporating the appropriate drag flux model and the population balance equation.