• Steel and Composite Structures
• /
• v.44 no.2
• /
• pp.199-210
• /
• 2022

This study build finite element analysis (FEA) models describing the bending events of coiled tubing (CT) at the wellhead and trips into the hole, accurately provide the state of stress and strain while the CT is in service. The bending moment and axial force history curves are used as loads and boundary conditions in the diametrical growth models to ensure consistency with the actual working conditions in field operations. The simulation diametrical growth results in this study are more accurate and reasonable. Analysis the factors influencing fatigue and diametrical growth shows that the internal pressure has a first-order influence on fatigue, followed by the radius of the guide arch, reel and the CT diameter. As the number of trip cycles increase, fatigue damage, residual stress and strain cumulatively increase, until CT failure occurs. Significant residual stresses remain in the CT cross-section, and the CT exhibits a residual curvature, the initial residual bending configuration of CT under wellbore constraints, after running into the hole, is sinusoidal. The residual stresses and residual bending configuration significantly decrease the buckling load, making the buckling and buckling release of CT in the downhole an elastic-plastic process, exacerbating the helical lockup. The conclusions drawn in this study will improve CT models and contribute to the operational and economic success of CT services.

• Steel and Composite Structures
• /
• v.44 no.2
• /
• pp.271-281
• /
• 2022

This study discusses challenges of running expandable profile liners (EPLs) to isolate trouble zones in directional section of a deep well, and summary the expandable profile liner technology (EPLT) field trial experience. Technically, the trial result reveals that it is feasible to apply the EPLT solving lost-circulation control problem and wellbore instability in the deep directional section. Propose schemes for optimizing the EPLT operation procedure to break through the existing bottleneck of EPLT in the deep directional section. Better-performing transition joints are developed to improve EPL string reliability in high borehole curvature section. High-performing and reliable expanders reduce the number of trips, offer excellent mechanical shaping efficiency, simplify the EPLT operation procedure. Application of the expansion and repair integrated tool could minimize the risk of insufficient expansion and increase the operational length of the EPL string. The new welding process and integrated automatic welding equipment improve the welding quality and EPL string structural integrity. These optimization schemes and recent new advancements in EPLT can bring significant economic benefits and promote the application of EPLT to meet future challenges.

• Architectural research
• /
• v.15 no.2
• /
• pp.59-68
• /
• 2013

To ameliorate a long-standing, persistent housing shortage in Korea, large-scale massive housing production has been an imperative, and the extensive growth highly values development and consumption. The state's priority for the quantitative growth of housing stock has proved to be successful, but the state faces with economic and environmental crises in a global era. To achieve the qualitative growth, the previous administration pronounced a green growth policy from the inception, and a series of strategic measures under a holistic plan have been taken widely and vigorously. As part of the strategies, the green home project was undertaken, and simultaneously the movement of green living led by the governance has been activated. However, little attention to the grassroots effort was paid and the efficacy hasn't been adequately addressed. This study examines the factors affecting green living of residents in multifamily housing. Based on public guidelines to green living, 106 specific items were drawn out and largely categorized into 6 areas (water, waste, transportation, air quality, consumption, and energy), and the questionnaire was constructed using them. Of 750 survey forms mailed out, 161 responses were returned and the collected data were used for statistical analysis. The findings indicated that varying degrees of green living was well practiced, the state-led green home project was relatively well recognized, and the green growth policy was strongly supported. Also the respondents' attitude toward green living were more associated with demographic variables than housing characteristics, and familiarity with green home project was related to attitudes toward green living. Since the on-going approach to green living has focused on simple and economical ways, it has proved to be effective but progressive strategies to make living greener are necessarily developed.

• Journal of Korean Society of Transportation
• /
• v.10 no.2
• /
• pp.5-24
• /
• 1992

This research presets the method of determining basic capacity of signalized intersection using the concept of ideal saturation flow rate. Vehicle discharge rates during green time were collected and studied as part of the preparation of Korean Highway Capacity Manual. From the result of this study the ideal saturation flow rate and saturation queue position were determined. In addition, based on the ideal saturation flow rate two geometric adjustment factors(lane width and grade adjustment factors) were studied. The results were presented in this paper.

• Proceedings of the KSR Conference
• /
• 2007.11a
• /
• pp.1744-1759
• /
• 2007

This study intended to identify the problems of the railroad which are raised as one of the 21C next-generation but to define the direction for the absence of the national policy and examine the competitiveness of railway transportation which is a Green Network with low environmental destruction and high energy efficiency as the continuable means of transportation for the 21st century with superiority to energy crisis caused by high oil price, conclusion of the Kyoto Protocol for worsened air pollution, and reduced cost of traffic jam.

• Journal of the Korean Society for information Management
• /
• v.32 no.3
• /
• pp.99-130
• /
• 2015

This study was conducted to develop and propose the evaluation indicators to evaluate the eco-friendliness of the library, when certified as the eco-friendly Green Libraries. To do this, we extracted the green library components through an analysis of the green library literatures and case studies, and surveyed the perceptions of the library staffs about the assessment factors. Finally, we developed the green library evaluation index with 11 evaluation areas, 31 evaluation items, and 135 evaluation indicators. The 11 evaluation areas are as follows; Land use and transportation, energy and environmental protection, materials and resources, water cycle management, maintenance management, ecological environment, the indoor environment, the library resources, the eco-education programs and campaigns, the staff and operations, and the computerization.

• Journal of the Korea Institute of Building Construction
• /
• v.12 no.4
• /
• pp.401-414
• /
• 2012

The adoption of Green Frame is expected to provide economic benefits, since construction costs are reduced by the in-situ production of precast concrete column and beam. The cost reduction can ultimately be realized by saving transportation costs and the overhead and profit of PC plants. The cost structure of Green Frame, which is built up using composite precast concrete members, is similar to that of a bearing-wall structure, but the difference in construction process has resulted in some cost differences for a few items. In particular, production and installation is the principal work involved in Green Frame made by precast concrete members, while form and concrete work is the principal work for a bearing-wall structure. As such, the rental time and fee for a tower crane should be compared through time analysis. To verify reliability, this study focused on developed residential projects to estimate the construction costs. Through this analysis, it was found that the costs of Green Frame were 1.57% lower than the costs of bearing-wall structure. The results of this study will help in the development of a management plan for the structural work of Green Frame.

• Journal of the Society of Naval Architects of Korea
• /
• v.47 no.2
• /
• pp.188-195
• /
• 2010

Green water load is an important parameter to be considered in designing a modern ship or offshore structures like FPSO and FSRU. In this research, a numerical simulation method for green water phenomenon is introduced. The Navier-Stokes equations and the continuity equation are used as governing equations. The equations are calculated using Finite Difference Method(FDM) in rectangular staggered grid system. To increase the numerical accuracy near the body, the Cartesian cut cell method is employed. The nonlinear free-surface during green water incident is defined by Marker-density method. The green waters on a box in regular waves are simulated. The simulation results are compared with other experimental and computational results for verification. To check the applicability to moving ship, the green water of the ship which is towed by uniform force in regular wave, is simulated. The ship is set free to heave and to surge.

• Journal of the Society of Naval Architects of Korea
• /
• v.45 no.3
• /
• pp.258-268
• /
• 2008

The radiation potential of a ship advancing in waves is studied using the 3D time-domain forward-speed free-surface Green function and the Green integral equation. Numerical solutions are obtained by making use of the 2nd order BEM(Boundary Element Method) which make it possible to take account of the line integral along the waterline in a rigorous manner. The 6 degree of freedom motion memory functions of a hemisphere and the Wigley seakeeping model obtained by direct integration of the time-domain 3D potentials over the wetted surface are presented for various Froude numbers.

• Journal of the Korean Institute of Landscape Architecture
• /
• v.32 no.4
• /
• pp.59-70
• /
• 2004

This study is about apartment greening to improve urban environment. To achieve this, questionnaires concerning the planter preferences were distributed. To improve perpendicular greening methods for apartments, MOCT (The Ministry of Construction and Transportation) reformed the law to obligate constructors to make apartment planters in June, 2000. But apartment residents take negative attitudes to making green space. It is difficult to manage the planters as well, so it is necessary that the point at making green spaces at apartments be scrutinized through questionnaires and an active method for making and managing the planter be made. The results show that apartment residents are reluctant to pay the expenses for planting and managing planters and have negative attitudes about plant purchases. If planting and managing of simplified planters are continually entrusted to residents, even vertical landscapes will be affected by illegal diversion and negligence as a result. Therefore, support from governments and local administrations are needed and legal obligation should be imposed on construction companies to install irrigation facilities.