• Proceedings of the Microbiological Society of Korea Conference
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• 2007.05a
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• pp.83-85
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• 2007

Deep-sea bacteria are adapted to extreme environments, such as high pressures and cold temperatures. We have isolated many piezophiles which grow well even under high pressures from deep-sea sediment. Shewanella violacea DSS12 and Moritella japonica DSK1 have the ability to grow at up to 70 MPa, and those bacteria have unique mechanisms of gene expression in response to high pressure conditions. The combination of gene expression systems in piezophiles, like the high pressure-dependent promoters and GFP reporter gene, may reveal highly fluorescent cells when exposed to high hydrostatic pressure conditions. It is predicted that a novel bio-sensing system can be made to probe high pressure environments using living bacteria. First, gene transformation into our piezophiles, strains DSS12 and DSK1, were examined. Eschericha coli S17-1 was used for bacterial conjugation with those piezophiles. As a result, the broad host range vector, pKT231, and the shuttle vector, pTH10, were successfully introduced to DSS12 and DSK1, respectively. Next, The pressure regulated promoters from DSS12 and DSK1 were cloned into proper vectors and combined with GFP as a reporter gene downstream of each promoter. The transformants of DSK1 and DSS12 with the recombinant pTH10 and pKT231 plasmid, which has cadA and glnA promoters (each of them is a pressure regulated promoter from DSK1 and DSS12, respectively) and GFP, were grown under high pressure and gene expression of GFP promoted by 50 MPa pressure was confirmed. This is a critical point to create a pressure-sensing bacteria, as the "High Pressure Glow Cells", which will indicate the level of environmental pressure using fluorescence of GFP as a reporter gene.

• Proceedings of the Korean Operations and Management Science Society Conference
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• 1996.04a
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• pp.373-376
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• 1996

The design development, and production of a product is one of the greatest challenges which flexible manufacturing systems face today. No matter how a company refines and controls the manufacturing process, if the product is not properly designed, it will not operate correctly or performed well. Therefore the focus on quality of design must be balanced. One such strategy certain to address the managerial and manufacturing of the future is concurrent engineering. Concurrent engineering calls for the consideration and inclusion of product design attributes satisfying all the design constraints such as customer requirements. Furthermore, concurrent engineering has been recently promoted in many industries as a response to competitive marketing pressures. Viewed as a systematic approach of creating high quality products and bringing them to market at lower cost and in significantly less time, it also attracts the attention of quality designers. In this paperm a methodology and model for optimizing the product design, especially selection of optimal design alternative, is developed. The focus of this paper is on product design as the most critical activity of concurrent engineering. The model is based on the customer requirements for quality. Customer requirements for a certain product can be grouped based on the various design attributes. The design attributes have the priorities. The number of design functions. Design attributes value are calculated, however these values are applied to the optimization method. Numerical example will be illustrated.

• Wind and Structures
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• v.18 no.6
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• pp.669-691
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• 2014

Since low-rise residential buildings are the most common and vulnerable structures in coastal areas, a reliable prediction of their performance under hurricanes is necessary. The present study focuses on developing a refined finite element model that is able to more rigorously represent the load distributions or redistributions when the building behaves as a unit or any portion is overloaded. A typical 5:12 sloped low-rise residential building is chosen as the prototype and analyzed under wind pressures measured in the wind tunnel. The structural connections, including the frame-to-frame connections and sheathing-to-frame connections, are modeled extensively to represent the critical structural details that secure the load paths for the entire building system as well as the boundary conditions provided to the building envelope. The nail withdrawal, the excessive displacement of sheathing, the nail head pull-through, the sheathing in-plane shear, and the nail load-slip are found to be responsible for the building envelope damage. The uses of the nail type with a high withdrawal capacity, a thicker sheathing panel, and an optimized nail edge distance are observed to efficiently enhance the building envelope performance based on the present numerical damage predictions.

• The Journal of Fisheries Business Administration
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• v.28 no.1
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• pp.51-70
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• 1997

The fishing industry of Korea is now i a critical transitional stage. That is, broadly speaking, there are two dominant factors that constrain the further development of Korea fishey and effective competition in the international fishing industry. First of all, the global fishing industry has experienced many significant changes due to the execution of U.N, maritime law, the establishment of EEZ(the Exclusive Economic Zones), the increased roles of WTO(the World Trade Organization) as well as Korea being a member of OECD(the Organization for Economic Co-operation and Development). Second, the fishing industry of Korea is faced with the following domestic troubles, such as the icreasing fishing expenses, insufficient labor supply, and the collapse of traditional local co-operative organizations of fishing villages, etc. However, the demand for aquatic products of home consumers not only continues to increase but also is shifting to select more valuable species, completely ignoring the above-mentioned serious pressures incurred by the Korean fishery. To solve these problems and keep developing steadily, it is necessary for the fishing industry of Korea to adopt a more active and flexible development pattern in order to reset up the regional economic base in fishing villages nation-wide and make the exploitation of fishing resources balance. The paper gives an reconsideration to the primary alternatives facing the Korean fishery and its prospective roles in a realistic and far-sighted attitude. It may serve as an endeavour in seeking an outlet for the fishing industry of korea to advance forwardly and lastingly.

• Korea-Australia Rheology Journal
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• v.16 no.4
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• pp.163-168
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• 2004

In this study, an ultrasonic technique was employed to obtain pressure-volume-temperature (PVT) rela­tionship of polymer melt by measuring ultrasonic velocities under various temperatures and pressures. The proposed technique was applied to on-line monitoring of injection molding process as an attempt to predict quality of molded parts. From the comparison based on Tait equation, it was confirmed that the PVT behav­ior of a polymer is well described by the variation of ultrasonic velocities measured within the polymer medium. In addition, the changes in part weight and moduli were successfully predicted by combining the data collected from ultrasonic technique and artificial neural network algorithm. The results found from this study suggest that the proposed technique can be effectively utilized to monitor the evolution of solid­ification within the mold by measuring ultrasonic responses of various polymers during injection molding process. Such data are expected to provide a critical basis for the accurate prediction of final performance of molded parts.

• Journal of Industrial Technology
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• v.23 no.A
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• pp.109-118
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• 2003

This paper is results of numerical works of investigating effects of horizontal drain arrangements on vacuum consolidation. Extensive numerical analyses were carried out to find the appropriate arrangements of horizontal drain of vacuum consolidation. Commercially available program of CRISP, well known to be good to modelling the behavior of clay material, was used Cam-clay model, based on the Critical State of Soil Mechanics(CSSM), was used to simulate the geotechnical engineering behavior of clay. Model test results carried out previously in the laboratory were compared with numerically estimated results and it was found that results about consolidational settlement with times were in good agreements. Based on this confirmation, parametric numerical study was performed to investigate effects of horizontal drain arrangements on vacuum consolidation with changing the vertical and horizontal spacings between drains for the given soil properties and vacuum. The effect of distance of drain located in top layer from the surface of the ground on the settlement due to vacuum was also investigated. As a results of numerical analyses, appropriate arrangements of horizontal drain to maximize the consolidation settlement due to vacuum were found. The mechanism of vacuum consolidation about the vacuum pressures being transferred to the effective stresses around drains was also evaluated.

• Geomechanics and Engineering
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• v.38 no.4
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• pp.397-408
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• 2024

Buried box culverts are crucial elements of transportation infrastructure. However, their behavior under foundation loads is not well understood, indicating a significant gap in existing research. This study aims to bridge this gap by conducting a detailed numerical analysis using the Finite Element Method and Abaqus software. The research evaluates the behavior of buried box culverts by examining their interaction with surrounding soil and the pressures from surface foundation loads. Key variables such as embedment depth, culvert wall thickness, concrete material properties, foundation pressure, foundation width, soil elastic modulus, and friction angle are altered to understand their combined effects on structural response. The methodology employs a validated 2D numerical model under plane strain conditions. Parametric studies highlight the critical role of culvert depth (H) in influencing earth pressure and bending moments. Foundation pressure and width demonstrate complex interdependencies affecting culvert behavior. Variations in culvert materials' elastic modulus show minimal impact. It was found that the lower wall of the buried culvert experiences higher average pressure compared to the other two walls, due to the combined effects of the culvert's weight and down drag forces on the side walls. Furthermore, while the pressure distribution on the top and bottom walls is parabolic, the pressure on the side walls follows a different pattern, differing from that of the other two walls.

• Journal of the Korea Concrete Institute
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• v.16 no.6 s.84
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• pp.841-850
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• 2004

The modeling of uplift pressure within dam, on the foundation on which it was constructed, and on the interface between the dam and foundation is a critical aspect in the analysis of concrete gravity dams, i.e. crack stability in concrete dam can correctly be predicted when uplift pressures are accurately modelled. Current models consider a uniform uplift distribution, but recent experimental results show that it varies along the crack faces and the procedures for modeling uplift pressures are well established for the traditional hand-calculation methods, but this is not the case for finite element (FE) analysis. In large structures, such as dams, because of smaller size of the fracture process zone with respect to the structure size, limited errors should occur under the assumptions of linear elastic fracture mechanics (LEFM). In this paper, the fracture behaviour of concrete gravity dams mainly subjected to uplift Pressure at the crack face was studied. Triangular type, trapezoidal type and parabolic type distribution of the uplift pressure including uniform type were considered in case of evaluating stress intensity factor by surface integral method. The effects of body forces, overtopping pressures are also considered and a parametric study of gravity dams under the assumption of LEFM is performed.

• Journal of the Computational Structural Engineering Institute of Korea
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• v.28 no.2
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• pp.197-205
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• 2015

Offshore structures for the gas production are exposed to the risk of gas leaks, and gas explosions can result in fatal damages to the primary structures as well as secondary structures. To minimize the damage from the critical accidents, the study of the dynamic response of structural members subjected to blast loads must be conducted. Furthermore, structural dynamic analysis has to be performed considering relationships between the natural frequency of structural members and time duration of the explosion loading because the explosion pressure tends to increase and dissipate within an extremely short time. In this paper, the numerical model based on time history data were proposed considering the negative phase pressure in which considerable negative phase pressures were observed in CFD analyses of gas explosions. The undamped single degree of freedom(SDOF) model was used to characterize the dynamic response under the blast loading. A blast wall of FPSO topside was considered as an essential structure in which the wall prevents explosion pressures from the process area to utility and working areas. From linear/nonlinear transient analyses using LS-DYNA, it was observed that dynamic responses of structures were influenced by significantly the negative time duration.

• Fire Science and Engineering
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• v.26 no.4
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• pp.77-81
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• 2012

This study of aims to provide basic data for improve the performance of air respirators that generate by bad influencing elements in fire emergency field. With three types of conditions set up for these tests, the pressures of containers have been extracted; the ambient temperatures have been checked, and the generation of moisture inside and outside container have been checked and identified. Specifically, these tests have been conducted at temperatures ranging between $-20{\sim}40^{\circ}C$. The pressures of containers have been extracted to reach between 0.4~0.8 MPa, using a pressure regulating valve. These tests have resulted in no change in the temperature and moisture outside the containers and no generation of moisture inside the containers as well. Although moisture has been generated inside the pressure gauge, the amount of moisture has not exceeded 25 $mg/m^3$, i.e. the limit suggested by the Korean Government. Therefore, it is judged that the moisture generated inside air respirators, which can be the most critical issue in the equipment, is likely to be caused in the process of managing the equipment or replacing air in the equipment at places of end-users, rather than in the process of manufacturing and production of the equipment.