• Journal of Radiation Protection and Research
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• v.10 no.2
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• pp.148-154
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• 1985

Radiation shield design for a shipping cask, KSC-1, was evaluated to verify that the cask can be used in the transportation of a spent fuel assembly discharged from KNU 5 & 6. Radiation source term of the spent fuel assembly was calculated with the computer program ORIGEN-79, QAD-CG, ANISN-KA and DOT 3.5 codes Were used in the shielding calculations and the nuclear cross section data needed was extracted from the DLC-23/CASK library. It is concluded that KSC-1 shipping cask satisfies the requirements specified in the relevant regulations under normal conditions of transport and under accident conditions in transport.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.20 no.1
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• pp.86-99
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• 2021

One of the methods to alleviate traffic congestion is to increase the efficiency of the roads by providing traffic condition information on road user and distributing the traffic. For this, reliability must be guaranteed, and quantitative real-time traffic speed prediction is essential. In this study, and based on analysis of traffic speed related to traffic conditions, historical data correlated with traffic flow were used as input. We developed an LSTM model that predicts speed in response to normal traffic conditions, along with a CNN-LSTM model that predicts speed in response to incidents. Through these models, we try to predict traffic speeds during the hour in five-minute intervals. As a result, predictions had an average error rate of 7.43km/h for normal traffic flows, and an error rate of 7.66km/h for traffic incident flows when there was an incident.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.29 no.4A
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• pp.373-384
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• 2009

For the first step on the quantitative evaluation of shrinkage reduction and differential shrinkage analysis of lightweight aggregate concrete, this study sets the moisture transport model of concrete by pre-absorbed water of porous lightweight aggregates and measured effective moisture diffusion coefficient, moisture capacity, degree of humidity supply and degree of humidity consumption by water binder ratio and aggregate type. The effective moisture diffusion coefficient in steady state caused by humidity difference between inside and outside of concrete had low value as low water-binder ratio. And in case of same water-binder ratio, effective moisture diffusion of mixtures used normal aggregates were lower than those used lightweight aggregates. To determine moisture store capability of concrete - moisture capacity, moisture contents were measured in 9 humidity conditions. As a result moisture contents of mixtures used lightweight aggregates was higher than mixtures used normal aggregates in all humidity conditions. This study measured lightweight aggregates' degree of humidity supply that applicable to normal atmospheric environment (above RH 50%) and made it quantitatively. Also amount of moisture release was set as a exponential function that represents a clear trend proportion to time and inverse proportion to humidity of the surroundings. As the result of measurement about degree of moisture consumption inside concrete following the internal consumption caused by cement hydration self-drying, it was showed that rapid decrease of humidity, around 10%, at early ages (7~10 days) when water-binder ratio is 0.3 and slow decrease around 5% and 1% when water-binder ratio is 0.4 and 0.5.

• Journal of Pharmaceutical Investigation
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• v.24 no.3
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• pp.19-25
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• 1994

The single-pass perfusion technique was employed in order to investigate the effect of water flux from the rat jejunum in the normal experimental conditions. Our results suggested that water flux below ${\pm}0.75%/cm$ of jejunal length was considered normal. Water flux was $-0.131\;{\pm}\;0.311%/cm$ of jejunal length in a citrate buffer and should be corrected in order to determine the permeabilities of the compounds. Perfusion rate up to 0.5 ml/min had no effects on the permeability of ampicillin. Neither the effective permeabilities nor the wall permeabilities of aminopenicillins were influenced by water flux during experiments in rats.

• Transactions of the Korean Society of Mechanical Engineers
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• v.19 no.8
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• pp.1989-1998
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• 1995

Characteristics of the flame propagation for normal and abnormal combustion in hydrogen premixture in a cylindrical constant-volume combustion chamber are studied numerically. A detailed hydrogen oxidation kinetic mechanism, mixture transport properties and a model describing spark ignition process are used. The calculated pressure-time history of the stable deflagration wave propagation agrees well with the experiment. The ignition of the premixture in the unburned gas, initiated by the hot spot, causes a transition from deflagration to detonation under some initial temperature and pressure. Under the initial conditions with high temperature and pressure, excessive ignition energy initiates a strong blast wave and a detonation wave that follows. The chemical reaction in the detonation wave is much more vigorous than that in the deflagration wave and the peak pressure in the detonation wave is much higher than the equilibrium value.

• 한국신재생에너지학회:학술대회논문집
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• 2008.05a
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• pp.550-553
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• 2008

In this paper, experiments of air-breathing proton exchange membrane fuel cell (PEMFC) for mobile devices were carried out according to the cathode conditions. These conditions are defined by the cathode flow field plate type (the channel type, the open type) and the cathode surface direction. Single cell and 6-cell stack were used in this experiments. The experimental results showed that the open type cathode flow field plate gave better performance for small size PEMFCs because the open type cathode plate allowed better air convection than the channel type cathode plate. In the experiments related to the direction of the slits on the cathode flow field plate, the horizontal slit cell was better than the vertical slit cell. With respect to the cathode surface direction, when the cathode surface is placed in the direction normal to the ground, PEMFC generated more stable power in the mass transport loss region.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2001.11b
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• pp.766-771
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• 2001

The package used to transport radioactive materials, which is called by cask, must be safe under normal and hypothetical accident conditions. These requirements for the cask design must be verified through test or finite element analysis. Since the cost for FE analysis is less than one for test. the verification by FE analysis is mainly used. But due to the complexity of mechanical behaviors. the results depends on how users apply the codes and it can cause severe errors during analysis. In this paper, finite element analysis is carried out for the 9 meters free drop and the puncture condition of the hypothetical accident conditions using LS-DYNA3D and ABAQUS/Explicit. We have investigated the analyzing technique for the free drop impact test of the cask and found several vulnerable cases to errors. The analyzed results were compared with each other. We have suggested a reliable and relatively simple analysis technique for the drop test of spent nuclear fuel casks.

• Nuclear Engineering and Technology
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• v.52 no.9
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• pp.2025-2033
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• 2020

Signature-based safeguards (SBS) is being developed to assist tradition nuclear material accountancy methods in tracking material in pyroprocessing facilities. SBS involves identifying off-normal scenarios that would result in improper movement of material in a pyroprocessing facilities and determining associated sensor response signatures. SBS investigations are undertaken in the computational space utilizing an electrochemical transport code known as enhanced REFIN with anodic dissolution (ERAD) to calculate the affect of off-normal conditions in the electrorefiner (ER) on material movement. Work is undertaken to experimentally validate the predictions and assumptions made by ERAD for off-normal occurrences. These experiments were undertaken on a benchtop scale and involved operating an electrochemical cell at 10 separate current densities for constant current operations to deposit U and Gd at a W cathode. These experiments were then modeled using ERAD to compare calculated predictions versus analytical experimental results it was found. It was discovered both the experimental and calculated results reflect a trend of increased codeposition of U and Gd with increasing current density. ERAD was thus demonstrated to be useful for predicting trends from anomalous operation but will require further optimization to be utilized as a quantitative design tool.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.37 no.9
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• pp.815-821
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• 2013

The efficiency and lifetime of a polymer electrolyte membrane fuel cell (PEMFC) system is critically affected by the humidity of the incoming gas, which should be maintained properly under normal operating conditions. Typically, the incoming gas of a fuel cell is humidified by an external humidifier, but few studies have reported on the device characteristics. In this study, a laboratory-scale planar membrane humidifier is designed to investigate the characteristics of water transport through a hydrophilic membrane. The planar membrane humidifier is immersed in a constant temperature bath to isolate the humidifier from the effect of temperature variations. The mass transfer capability of the hydrophilic membrane is first examined under isothermal conditions. Then, the mass transfer capability is investigated under various conditions. The results show that water transport in the hydrophilic membrane is significantly affected by the flow rate, operating temperature, operating pressure, and flow arrangement.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.16 no.4
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• pp.92-106
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• 2017

The adverse weather is known as a factor that interrupts traffic flow and causes traffic accidents and traffic congestion by lowering visibility of drivers. Especially, in case of fog unlike any other weather conditions, traffic accidents lead to serious accidents and the fatality of the accidents is known to be high. This paper aims to analyze uninterrupted traffic flow characteristics under foggy conditions among adverse weathers. The traffic volumes and speeds under foggy and normal conditions were analyzed. Results indicated that fog with low visibility causes the most insignificant reduction in traffic volumes. On the other hand, the reduction in the speeds due to low visibility was evident. In addition, the relationship between flow, speed, and density in fog were analyzed. Analysis results showed that the fog with less than 200m visibility had clear impact on traffic flow.