• 한국터널공학회:학술대회논문집
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• 2005.04a
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• pp.189-201
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• 2005

Brittle failure has been detected in over-stressed rock mass during the construction of oil storage cavern. The main characteristics of stress induced brittle failure of the site are introduced. Various evaluation and measures are sought to stabilize the over-stressed rock mass. The major results from numerical analysis of the cavern are presented, and from current microseismic monitoring to detect hazard from brittle failure are presented.

• Structural Engineering and Mechanics
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• v.23 no.6
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• pp.615-634
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• 2006

Seismic response of the liquid storage tanks isolated by the elastomeric bearings and sliding systems is investigated under near-fault earthquake motions. The fault normal and parallel components of near-fault motion are applied in two horizontal directions of the tank. The continuous liquid mass of the tank is modeled as lumped masses known as sloshing mass, impulsive mass and rigid mass. The corresponding stiffness associated with these lumped masses has been worked out depending upon the properties of the tank wall and liquid mass. It is observed that the resultant response of the isolated tank is mainly governed by fault normal component with minor contribution from the fault parallel component. Further, a parametric study is also carried out to study the effects of important system parameters on the effectiveness of seismic isolation for liquid storage tanks. The various important parameters considered are: aspect ratio of tank, the period of isolation and the damping of isolation bearings. There exists an optimum value of isolation damping for which the base shear in the tank attains the minimum value under near-fault motion. The increase of damping beyond the optimum value will reduce the bearing and sloshing displacements but increases the base shear. A comparative performance of five isolation systems for liquid storage tanks is also studied under normal component of near-fault motion and found that the EDF type isolation system may be a better choice for design of isolated tank in near-fault locations. Finally, it is also observed that the satisfactory response can be obtained by analysing the base-isolated tanks under simple cycloidal pulse instead of complete acceleration history.

• Journal of Internet Computing and Services
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• v.17 no.2
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• pp.1-9
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• 2016

Users are provided infrastructure such as CPU, memory, network, and storage as IaaS (Infrastructure as a Service) service on cloud computing environments. However storage instances cannot support the maximum storage capacity that SQL servers can use, because the capacity of instances provided by service providers is usually limited. In this paper, we propose a method of securing mass storage capacity for SQL servers by sharing network disks with limited storage capacity. We confirmed through experiments that it is possible to secure mass storage capacity, which exceeds the maximum storage capacity provided by an instance with Amazon EBS on Amazon EC2 Windows environments, and it is possible to improve the overall performance of the SQL servers by increasing the disk capacity and performance.

• Journal of the Korean Society of Environmental Restoration Technology
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• v.19 no.2
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• pp.83-93
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• 2016

This study purposed to examine the water retention capacity of floor litter in deciduous forests. Water holding capacity(WHC) and interception storage capacity of Alnus hirsuta Turcz. ex Rupr., Quercus acutissima, Quercus mongolica litters were experimentally estimated. Physical characteristics of litters were also obtained to understand the relationships between water-retention capacity and litter characteristics. Experiments showed that WHC increases with specific volume of litter, varying 244.4% to 416.8% of its dry mass. Interception storage have estimated with rainfall simulation experiments. Maximum interception storage ($C_{max}$) and minimum interception storage ($C_{min}$) of litters were 220% and 138% of dry mass in Alnus hirsuta Turcz. ex Rupr., 218% and 137% in Quercus acutissima, and 240% and 156% in Quercus mongolica. Both $C_{max}$ and $C_{min}$ increased linearly with litter mass, and the values of $C_{min}$ in broadleaf litters have also linear relation to leaf area.

• Journal of Korean Society of Water and Wastewater
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• v.22 no.2
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• pp.233-238
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• 2008

Recently, rainwater harvesting facilities have increasingly constructed mainly in elementary schools and government buildings. Nevertheless, few methods are available for efficient planning and design of rainwater harvesting facilities by considering the weather conditions and purpose of rainwater management in each site, which may lead to a construction of uneconomic facilities. The current method estimates the size of rainwater storage tank by multiplying the size of building or plottage with a certain ratio and has many limitations. In this study, we first developed a method for planning and design of rainwater storage facilities using $Rainstock^{TM}$ model, which is based on mass balance, and economic analysis. Then, the model was applied for the design of a rainwater harvesting facility in a building with the catchment area of $1,000m^2$. The model calculation indicated that the economic feasibility of rainwater harvesting depends on not only the size of storage tank but also the water usage rate. When the water usage rate is $1m^3/day$, the rainwater harvesting facility is not cost-effective regardless of the size of the storage tank. With increasing the water usage rate, the economical efficiency of the facility was improved for a specific size of the storage tank. Based on the model calculation, the optimum tank sizes for $5m^3/day$ and $10m^3/day$ of water usage rates were $24m^3$ and $57m^3$, respectively. It is expected that the model is useful for optimization of rainwater storage facilities in planning and designing steps.

• Tunnel and Underground Space
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• v.22 no.3
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• pp.188-195
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• 2012

Using a computational fluid dynamics (CFD) code, FLUENT, the present study investigated the thermal stratification behavior of Lyckebo storage in Sweden, which is the very first large-scale rock cavern for underground thermal energy storage. Heat transfer analysis was carried out for numerical cases with different temperatures of the surrounding rock mass in order to examine the effect of rock mass heating due to periodic storage and production of thermal energy on thermal stratification and heat loss. The change of thermal stratification with respect to time was quantitatively examined based on an index of the degree of stratification. The results of numerical simulation showed that in the early operational stage where the surrounding rock mass was less heated, the stratification of stored thermal energy was rapidly degraded over time, but the degradation and heat loss tended to reduce as the surrounding rock mass was heated during a long period of operation.

• 한국신재생에너지학회:학술대회논문집
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• 2010.06a
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• pp.225.1-225.1
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• 2010

Within recent years attention has been focused on the method of hydrogen storage using metal hydride reactor due to its high energy density, durability, safety and low operating pressure. In this paper, a numerical study is carried out to investigate the coupled heat and mass transfer process for absorption in a cylindrical metal hydride hydrogen storage reactor using a newly developed model. The simulation results demonstrate the evolution of temperature, equilibrium pressure, H/M atomic ratio and velocity distribution as time goes by. Initially, hydrogen is absorbed earlier from near the wall which sets the cooling boundary condition owing to that absorption process is exothermic reaction. Temperature increases rapidly in entire region at the beginning stage due to the initial low temperature and enough metal surface for hydrogen absorption. As time goes by, temperature decreases slowly from the wall region due to the better heat removal. Equilibrium pressure distribution appears similarly with temperature distribution for reasons of the function of temperature. This work provides a detailed insight into the mechanism and corresponding physicochemical phenomena in the reactor during the hydrogen absorption process.

• 한국신재생에너지학회:학술대회논문집
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• 2007.06a
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• pp.831-835
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• 2007

Energy Saving is one of worldwide emerging issues. These days, applicable techniques of railway vehicle's regenerative energy are investigating in worldwide railway industries. Energy saving methods are "Downsizing energy loss" and "Re-utilizing kinetic energy". Useful plans for Downsizing energy loss are "adjusting operation table" and "optimizing running pattern". Furthermore, regenerative energy that is produced with decreasing speed and stoping, is an important element with reducing vehicle's weight, raising equipment 's efficiency, decreasing running resistance and re-configurating running pattern. Sustainable energy storage mass : Flywheel, EDLC(electrical double layer capacitor) and Secondary battery are applied in overseas, but these cases are not reported within the country. This research is reported for problems and economical validity that comes from by installing sustainable regenerative energy storage system in korean railway industries.

• Journal of the Optical Society of Korea
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• v.13 no.4
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• pp.456-463
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• 2009

We introduce a holographic data storage system for intermediating between small data sets and mass holographic data recording. It employs a holographic sequentially superimposed recording technique. We discuss a time scheduling technique for making uniform reconstruction of sequentially recorded holograms and we show experimental results. We also discuss the Bragg selectivity of sequentially recorded holograms. The maximum storage density of our system is estimated to be 224kbit/$mm^2$. Our system is useful as an intermediate recording system before recording mass holographic data in a larger system.

• International journal of steel structures
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• v.18 no.4
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• pp.1167-1176
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• 2018

Steel cylindrical tanks are widely used for the storage of hazardous substances of which leakage must be prevented under any circumstances. However, the dynamic response of the steel cylindrical liquid storage tank depends sensitively on the fluid-structure interaction and the vibration of the tank structure and necessitates clarification for the safety of the tank structure. This paper presents the results of shaking table tests performed to examine the dynamic behavior of a scaled cylindrical steel tank model considering the presence or not of fixed roof and added mass at the top of the tank for various fluid levels. The test results confirm the occurrence of both beam-type and oval-type vibration modes and show that the larger content of liquid inside the container amplified the acceleration along the height of the cylindrical tank. The oval-type vibration modes are seen to be more dominant in case of large water-to-structure mass ratio.