• Journal of the Society of Naval Architects of Korea
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• v.53 no.2
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• pp.162-169
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• 2016

A new concept of membrane type LNG CCS was proposed. Also, its static behavior was numerically analyzed considering the interaction between primary and secondary barrier together with securing device. Hull deflection was taken into account as an external load, together with temperature distribution across the barriers. The suggested numerical model considers both sliding and contact between the two mating surfaces of both the primary and secondary barrier, and anisotropic material behavior of plywood, R-PUF was also taken into account. Furthermore, detailed local strength was evaluated for the securing device, which is arranged between two barriers to hold the primary barrier. It was confirmed through the numerical analysis that the new concept of membrane type CCS was structurally safe under static loading condition and securing concept was structurally reliable.

• Journal of the Korean Institute of Gas
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• v.3 no.3 s.8
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• pp.58-64
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• 1999

This paper has been analyzed for the stress behavior problems of the ring knot membrane unit using the finite element method about the pitch design of the membrane unit, which is one of the most important parameters in manufacturing of the membrane type LNG storage tanks. The FEM results have been compared those of the existing pitch design length. The safety problem of the ring knot membrane model, which is considered in this study, does not come out any more no matter what the pitch length is used in the extra large LNG storage tanks. But in the case of the membrane for LNG tankers, it is advantageous to design the pitch short because of fatigue strength caused by repeated loadings. Looking at the deformation behaviors of the membrane corrugation, the deformation of the hight in the y direction occurs $15{\~}50\%$ more than that of the width in the z direction. It shows also that the deformation of the membrane with $-162^{\circ}C$ cryogenic temperature is not so great compared with the deformation by hydrostatic pressure.

• Membrane Journal
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• v.22 no.3
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• pp.224-233
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• 2012

To improve permeation performance of gas separation membrane, polysulfone hollow fiber membrane was prepared by wet-dry phase inversion method using Triton X-100 as non-ionic additive. And variation of gas permeation behavior by additive was investigated. Various spinning conditions such as air gap, concentration of polymer, dope tank temperature were controlled and these effects were studied. The morphology and gas permeation property of hollow fiber membranes were investigated using scanning electron microscope (SEM) and bubble flow meter respectively. We confirmed that the membranes added with Triton X-100 had a smooth external skin at various air gap length conditions. The macrovoids of these hollow fiber membranes were more developed with increase of air-gap from 4 to 90 cm and that induced higher permeance. The permeance of polysulfone membranes has the higher value at comparatively lower concentration polymer (30 wt% polysulfone) and lower concentration of additive (15 wt% Triton X-100). When temperature in dope tank was controlled, the membranes prepared at $100^{\circ}C$ showed low permeance because of volatilization of additive and solvent.

• Journal of Korean Society of Water and Wastewater
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• v.25 no.6
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• pp.981-987
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• 2011

Biologically treated water contains a large quantity of organic matters and microorganisms which can cause various problems to membrane. The membrane fouling occurred by these reasons is hard to control by single physical cleaning. This study analyzes the efficiency of aeration with chemical backwashing and foulants removal during chemical backwashing. The cleaning efficiency improves when the chemical concentration is high and the contact time of chemical is long. Chemical backwashing with aeration shows exceptional cleaning efficiency which leads the physical cleaning is required during chemical backwashing since it forms flow inside the membrane submerged tank. From the foulants removal analysis, the particles such as turbidity and TOC removal rate increase when the aeration is applied. Dissolved matter of DOC and UV254 removal is dependent on higher chemical concentration. According to FTIR analysis, one of major foulants, the polysaccharide is controlled by the chemical backwashing with aeration condition.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2003.11a
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• pp.91-95
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• 2003

There is a problem to be solved for improvement of durability and safety supervision. When you do the waterproofing and anticorrosive work of main concrete from the design stage, the material and method of construction need to be correctly applied to appropriate circumstance conditions. Epoxy have mostly been used for concrete water tank structure. Lately, lots of subjects on adaption of polyurea resin waterproofing and anticorrosive are under discussion. Then, we attempt to approach by evaluating and comparing every capabilities with another waterproofs in this study. Performance evaluation items include the adherence performance, the imprint of seal performance, temperature dependence performance, promotion weatherizing ability, inner chemical performance, drinking water eruptive performance. Through the experiment analysis, we found that the polyurea resin waterproofing membrane is dominantly superior to other waterproofs. According to this study, we suggest the polyurea resin waterproofing membrane as a new waterproofing material for concrete structure.

• Journal of the Korea Institute of Building Construction
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• v.2 no.1
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• pp.131-138
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• 2002

There is a problem to be solved for improvement of durability and safety supervision. When you do the waterproofing work of main concrete from the design stage, the material and method of construction need to be correctly applied to appropriate circumstance conditions. Epoxy have mostly been used for concrete water tank structure. Lately, lots of subjects on adaption of polyurea resin waterproofing and anticorrosive are under discussion. Then, we attempt to approach by evaluating and comparing every capabilities with another waterproofs in this study. Performance evaluation items include the adherence performance, the imprint of seal performance, temperature dependence performance, promotion weatherizing ability, Inner chemical performance. drinking water eruptive performance. Through the experiment analysis, we found that the polyurea resin waterproofing membrane is dominantly superior to other waterproofs. According to this study, we suggest the polyurea resin waterproofing membrane as a new waterproofing material for concrete structure.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2003.05a
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• pp.91-95
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• 2003

There is a problem to be solved for improvement of durability and safety supervision. When you do the waterproofing and anticorrosive work of main concrete from the design stage, the material and method of construction need to be correctly applied to appropriate circumstance conditions. Epoxy have mostly been used for concrete water tank structure. Lately, lots of subjects on adaption of polyurea resin waterproofing and anticorrosive are under discussion. Then, we attempt to approach by evaluating and comparing every capabilities with another waterproofs in this study. Performance evaluation items include the adherence performance. the imprint of seal performance, temperature dependence performance. promotion westernizing ability, inner chemical performance. drinking water eruptive performance. Through the experiment analysis, we found that the polyurea resin waterproofing membrane is dominantly superior to other waterproofs. According to this study, we suggest the polyurea resin waterproofing membrane as a new waterproofing material for concrete structure.

• Journal of the Society of Naval Architects of Korea
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• v.47 no.2
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• pp.233-241
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• 2010

Scaffolding system in the membrane LNG carrier is a steel structure composed of various pipe-shaped members connected by specific coupling devices. In this study, the automatic design program for scaffolding system in membrane LNG carrier has been developed. It enables user to arrange members easily considering design constraints and input variables such as size of tank, position of legs, level height and so on. In addition to that, it creates finite element analysis model with loading and boundary conditions automatically and carries out structural analysis. With post processor based a state-of-the-art computer graphics, users can easily check the results of structural analysis and make a report for structural safety of scaffolding system.

• Membrane and Water Treatment
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• v.3 no.2
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• pp.113-121
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• 2012

Up-flow multi-layer bioreactor (UMBR) is a hybrid system using dual sludge that consists of an up-flow multi-layer bioreactor as anaerobic/anoxic suspended growth microorganisms followed by an aeration tank. The UMBR acts as a primary settling tank, anaerobic/anoxic reactor, thickener which requires low energy due to mixing by up-flow stream. This study focused on using a pilot UMBR plant with capacity of 20-30 $m^3$/day for domestic wastewater in HCMC. HRTs of UMBR and aeration tank were 4.8 h and 7.2 h, respectively. The average MLSS of UMBR ranged from 10,000-13,600 mg/l SS. Internal recycle rate and sludge return were 200-300% and 150-200%, respectively. The results obtained from this study at flow rate of 20 $m^3$/day showed that removal of COD, SS, TKN, N-$NH_4$, T-N, and color were 91%, 87%, 86%, 80%, 91% and 91%, respectively.

• Earthquakes and Structures
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• v.26 no.5
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• pp.337-348
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• 2024

This paper presents a new seismic isolation design for liquid storage tank (LST). The seismic isolation system includes: LST, flexible membrane, sand mat and rolling seismic isolation devices. Based on the mechanical equilibrium theory, the symmetric concave rolling restoring force model of the isolation device is derived. Based on the elasticity theory and restoring force model of the seismic isolation, a simplified mechanical model of LST with the new seismic isolation is established. The rationality of the seismic isolation design of LST is explored. Meanwhile, the seismic response of the new seismic isolation LST is investigated by numerical simulation. The results show that the new seismic isolation tank can effectively reduce the seismic response, especially the control of base shear and overturning moment, which greatly reduces the risk of seismic damage. The seismic reduction rate of the new seismic isolation storage tanks in Class I, II, and III sites is better than that in Class IV sites. Moreover, the seismic isolation device can effectively control the ground vibration response of storage tanks with different liquid heights. The new seismic isolation LST design provides better isolation for slender LSTs than for broad LSTs.