• Journal of the Korean Institute of Gas
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• v.17 no.4
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• pp.58-69
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• 2013

This paper presents production data analysis for two production wells located in the shale gas field, Canada, with the proper analysis method according to each production performance characteristics. In the case A production well, the analysis was performed by applying both time and superposition time because the production history has high variation. Firstly, the flow regimes were classified with a log-log plot, and as a result, only the transient flow was appeared. Then the area of simulated reservoir volume (SRV) analyzed based on flowing material balance plot was calculated to 180 acres of time, and 240 acres of superposition time. And the original gas in place (OGIP) also was estimated to 15, 20 Bscf, respectively. However, as the area of SRV was not analyzed with the boundary dominated flow data, it was regarded as the minimum one. Therefore, the production forecasting was conducted according to variation of b exponent and the area of SRV. As a result, estimated ultimate recovery (EUR) increased 1.2 and 1.4 times respectively depending on b exponent, which was 0.5 and 1. In addition, as the area of SRV increased from 240 to 360 acres, EUR increased 1.3 times. In the case B production well, the formation compressibility and permeability depending on the overburden were applied to the analysis of the overpressured reservoir. In comparison of the case that applied geomechanical factors and the case that did not, the area of SRV was increased 1.4 times, OGIP was increased 1.5 times respectively. As a result of analysis, the prediction of future productivity including OGIP and EUR may be quite different depending on the analysis method. Thus, it was found that proper analysis methods, such as pseudo-time, superposition time, geomechanical factors, need to be applied depending on the production data to gain accurate results.

• Journal of Navigation and Port Research
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• v.46 no.6
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• pp.491-500
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• 2022

It has been noted that an accurate estimation of wind loads on offshore structures such as an FLNG (Liquefied Natural Gas Floating P roduction Storage Offloading Units, LNG FPSOs) with a large topside plays an important role in the safety design of hull and mooring system. Therefore, the present study aims to develop a computational model for estimating the wind load acting on an FLNG. In particular, it is the sequel to the previous research by the author. The numerical computation model in the present study was modified based on the previous research. Numerical analysis for estimating wind loads was performed in two conditions for an interval of wind direction (α), 15° over the range of 0° to 360°. One condition is uniform wind speed and the other is the NPD model reflecting the wind speed profile. At first, the effect of sand-grain roughness on the speed profile of the NPD model was studied. Based on the developed NPD model, mesh convergence tests were carried out for 3 wind headings, i.e. head, quartering, and beam. Finally, wind loads on 6-degrees of freedom were numerically estimated and compared by two boundary conditions, uniform speed, and the NPD model. In the present study, a commercial RANS-based viscous solver, STAR-CCM+ (ver. 17.02) was adopted. In summary, wind loads in surge and yaw from the wind speed profile boundary condition were increased by 20.35% and 34.27% at most. Particularly, the interval mean of sway (45° < α <135°, 225° < α < 315°) and roll (60° < α < 135°, 225° < α < 270°) increased by 15.60% and 10.89% against the uniform wind speed (10m/s) boundary condition.

• Computers and Concrete
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• v.31 no.3
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• pp.267-276
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• 2023

The main purpose of the current research is to develop an efficient two variables trigonometric shear deformation beam theory to investigate the buckling behavior of symmetric and non-symmetric functionally graded carbon nanotubes reinforced composite (FG-CNTRC) beam resting on an elastic foundation with various boundary conditions. The proposed theory obviates the use to shear correction factors as it satisfies the parabolic variation of through-thickness shear stress distribution. The composite beam is made of a polymeric matrix reinforced by aligned and distributed single-walled carbon nanotubes (SWCNTs) with different patterns of reinforcement. The material properties of the FG-CNTRC beam are estimated by using the rule of mixture. The governing equilibrium equations are solved by using new analytical solutions based on the Galerkin method. The robustness and accuracy of the proposed analytical model are demonstrated by comparing its results with those available by other researchers in the existing literature. Moreover, a comprehensive parametric study is presented and discussed in detail to show the effects of CNTs volume fraction, distribution patterns of CNTs, boundary conditions, length-to-thickness ratio, and spring constant factors on the buckling response of FG-CNTRC beam. Some new referential results are reported for the first time, which will serve as a benchmark for future research.

• Journal of Biosystems Engineering
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• v.21 no.4
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• pp.429-435
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• 1996

A wind tunnel consisting of two air flow conditioners with polycarbonate pipes, a plant growth room, a suction fan and fan controller, and fluorescent lamps, was designed to investigate the interactions between the growth of plug seedlings under artificial light and their Physical environments. Light transmissivities in the plant growth room based on the photosynthetic photon flux density and photosynthetically active radiation was appeared to be 96.3% and 96.8%, respectively. Measurement showed a uniformity in the vertical profiles of air current speed at the middle and rear regions of plug trays in wind tunnel. This result indicated that the development of a wind tunnel based on the design criteria of the American Society of Mechanical Engineers was adequate. Air current speed inside the plug stand was significantly decreased due to the resistance by the leaves of plug seedlings and boundary layer developed over and below the plug stand. Driving force to facilitate the diffusion of gas inside the plug stand might be regarded as extremely low. Aerodynamic characteristics above the plug stand under artificial light were investigated. As the air current speed increased, zero plane displacement decreased but roughness length and frictional velocity increased. Zero plane displacement linearly increased with the average height of plug seedlings. The wind tunnel developed in this study would be useful to investigate the effects of air current speed on the microclimate over and inside the plug stand and to collect basic data for a large-scale plug production under artificial light in a semi-closed ecosystem.

• Korean Journal of Remote Sensing
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• v.33 no.6_2
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• pp.1159-1169
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• 2017

Since 1970's, various satellite remote sensing technology has been developed and accumulation of observational data has been carried out, and coastal environment monitoring research is being conducted through analysis of relationship between satellite remote sensing data and coastal sedimentary environment. However, generation of coastal thematic maps by various national agencies are not included in the production of coastal themes using satellite imagery. In this study, we want to deduct the current problems through survey of marine spatial information provided by the government. The purpose of this study is to investigation the direction of the development of large scale coastal thematic maps by analyzing coastal boundary map, coastal topographic map and coastal sedimentary facies map.

• Journal of Advanced Research in Ocean Engineering
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• v.1 no.2
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• pp.106-114
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• 2015

In the fabrication of offshore oil and gas facilities, the significance of dimension control is growing continuously. But, it is difficult to determine the deformation of the structure during fabrication by simple lab tests due to the large size and the complicated shape. Strain-boundary method (a kind of shrinkage method) based on the shell element was proposed to predict the welding distortion of a structure effectively. Modeling of weld geometry in shell element is still a difficult task. In this paper, a concept of imaginary temperature pair is introduced to handle the effect of geometric factors such as groove shape, plate thickness and pass number, etc. Single pass imaginary temperature pair formula is derived from the relation between the groove area and the FE mesh size. By considering the contribution of each weld layer to the whole weldment, multi-pass imaginary temperature is also derived. Since the temperature difference represents the distortion increment, cumulative distortion curve can be drawn by integrating the temperature difference. This curve will be a useful solution when engineers meet some problems occurred in the shipyard. A typical example is shown about utilization of this curve. Several verifications are conducted to examine the validity of the proposed methodology. The applicability of the model is also demonstrated by applying it to the fabrication process of the heavy ship block. It is expected that the imaginary temperature model can effectively solve the modeling problem in shell element. It is also expected that the cumulative distortion curve derived from the imaginary temperature can offer useful qualitative information about angular distortion without FE analysis.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.34 no.10
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• pp.1471-1478
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• 2010

Microforming processes have recently attracted considerable attention from industry and academia since they enable the production of microscale parts using various materials at a high production rate, minimize material loss, and provide parts with excellent mechanical properties. However, for successful development and applications of the microforming process it is critical to take the tribological size effect into consideration because previous studies have shown that traditional friction models for macroscale forming generate significantly erroneous results in the case of microforming. In this paper, we performed scaled ring compression experiments to investigate the tribological size effect of aluminum and brass materials in microforming. The sensitivity of the interfacial friction to the deformation characteristics of the ring was quantitatively analyzed by the finite element analysis. In addition, a friction model based on slip line field and upper boundary techniques was used to theoretically explain the friction mechanism in microforming.

• Spatial Information Research
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• v.5 no.1
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• pp.43-59
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• 1997

There are currently more than tens of thematic maps in Korea. Among them, there are some thematic maps which are used by one organization only by which was made, and there are common thematic maps which are used by several organizations. In this study, among many kinds of common thematic maps which are currently used, the common thematic maps which will be digitized for parts of NGIS project were chosen and the priority of project was established. After selecting five maps from the common thematic maps classified as the first ranking, current land use map, parcel-address map, administrative boundary map, urban planning map and road map, the area of CheJoo Island was digitized as a pilot project. Through the pilot project of CheJoo Island, the level of application was verified, and the method was presented in order to reduce the trial and error in the process of this production after analyzing the matter from the pilot project. The direction for digitizing common thematic maps was presented based on the result of the pilot project, in addition to, the detail plan was established after deciding the number of people needed, the amount of money spent, and the period needed for making digital maps nationwide.

• KIEAE Journal
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• v.16 no.5
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• pp.73-79
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• 2016

Purpose: In order to improve the energy performance of existing buildings, so actively promoted green remodeling business. Also, improvement of the performance of envelope system of apartment housing is an absolute. The purpose of implementation of the data base and application plan of the envelope system for green remodeling of apartment housing. Method: For this study, It proposed a classification system of green remodeling envelope system constructed actual to select the applicable representative method and input material of apartment housing for green remodeling. In this study, divided into construction waste processing stage and production phase of the material for the boundary of the system, and implementation the classification system of the envelope system for applicable green remodeling. For this, established 6 environmental impact categories database. Result: As a result of various suggestions were available for case study research, alternative combinations of existing combinations than six kinds of environmental impact insulation system with superior input materials combining 96 kinds, window system, 12 kinds for determining the applicability of the established database. Depending on the account for a large proportion if compared to the detailed analysis of the environmental impact resulting from the production phase and disposal phase was analyzed that the operating management of the necessary input materials. Is considered that the economic performance and integrated energy performance required by the applicable public housing green remodeling evaluation techniques considered for future improvements insulation sheath.

• Asian-Australasian Journal of Animal Sciences
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• v.18 no.7
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• pp.1022-1028
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• 2005

The objectives of this study were to evaluate and compare the environmental load of two different concentrate feed supply systems to the Japanese domestic livestock industry using the Life-cycle Assessment (LCA) method. The current system was defined as that requiring 11.469 million tons of corn imported from the US by sea transport and supplied as concentrate feed to the Japanese domestic livestock industry. The new system proposed by Kaku et al. in 2004 was defined as where 802,830 tons of US imported corn would not be planted in US and would be replaced by barley planted in 278 thousand ha of Japanese domestic land left fallow for the past year. In this case, 909,000 tons of domestic harvest barley would have been supplied as concentrate feed to the Japanese domestic livestock industry in 2000. The activities taken into account within the two system boundaries were three stages: concentrate feed production, feed transportation and gas emission from the soil by chemical fertilizer. Finished compost was regarded as organic fertilizer and was put instead of chemical fertilizers within the system boundary. Adoption of this new concentrate feed supply system by the Japanese domestic livestock industry could reduce 78,462 tons $CO_2$-equivalents of global warming potential, 347 tons $SO_2$-equivalents of acidification potential, 54 tons $PO_4$-equivalents of eutrophication potential and 0.842 million GJ as energy consumption below 2,000 levels. This LCA study comparing two Japanese domestic livestock concentrate feed supply systems showed that the stage of feed transport contributed most to global warming and the stage of emission from the soil contributed most to acidification and eutrophication. The Japanese domestic livestock industry could participate in emissions trading with $CO_2$-equivalents reduced by shifting from some imported US corn as a concentrate feed to domestic barley planted in land left fallow. In that case the Japanese government could launch emissions trading in accordance with Kyoto Protocol in the future.