• Title/Summary/Keyword: Practical Engineering

Search Result 8,239, Processing Time 0.041 seconds

Scheme on Environmental Risk Assessment and Management for Carbon Dioxide Sequestration in Sub-seabed Geological Structures in Korea (이산화탄소 해양 지중저장사업의 환경위해성평가관리 방안)

  • Choi, Tae-Seob;Lee, Jung-Suk;Lee, Kyu-Tae;Park, Young-Gyu;Hwang, Jin-Hwan;Kang, Seong-Gil
    • Journal of the Korean Society for Marine Environment & Energy
    • /
    • v.12 no.4
    • /
    • pp.307-319
    • /
    • 2009
  • Carbon dioxide capture and storage (CCS) technology has been regarded as one of the most possible and practical option to reduce the emission of carbon dioxide ($CO_2$) and consequently to mitigate the climate change. Korean government also have started a 10-year R&D project on $CO_2$ storage in sea-bed geological structure including gas field and deep saline aquifer since 2005. Various relevant researches are carried out to cover the initial survey of suitable geological structure storage site, monitoring of the stored $CO_2$ behavior, basic design of $CO_2$ transport and storage process and the risk assessment and management related to $CO_2$ leakage from engineered and geological processes. Leakage of $CO_2$ to the marine environment can change the chemistry of seawater including the pH and carbonate composition and also influence adversely on the diverse living organisms in ecosystems. Recently, IMO (International Maritime Organization) have developed the risk assessment and management framework for the $CO_2$ sequestration in sub-seabed geological structures (CS-SSGS) and considered the sequestration as a waste management option to mitigate greenhouse gas emissions. This framework for CS-SSGS aims to provide generic guidance to the Contracting Parties to the London Convention and Protocol, in order to characterize the risks to the marine environment from CS-SSGS on a site-specific basis and also to collect the necessary information to develop a management strategy to address uncertainties and any residual risks. The environmental risk assessment (ERA) plan for $CO_2$ storage work should include site selection and characterization, exposure assessment with probable leak scenario, risk assessment from direct and in-direct impact to the living organisms and risk management strategy. Domestic trial of the $CO_2$ capture and sequestration in to the marine geologic formation also should be accomplished through risk management with specified ERA approaches based on the IMO framework. The risk assessment procedure for $CO_2$ marine storage should contain the following components; 1) prediction of leakage probabilities with the reliable leakage scenarios from both engineered and geological part, 2) understanding on physio-chemical fate of $CO_2$ in marine environment especially for the candidate sites, 3) exposure assessment methods for various receptors in marine environments, 4) database production on the toxic effect of $CO_2$ to the ecologically and economically important species, and finally 5) development of surveillance procedures on the environmental changes with adequate monitoring techniques.

  • PDF

Effects of Encapsulation Layer on Center Crack and Fracture of Thin Silicon Chip using Numerical Analysis (봉지막이 박형 실리콘 칩의 파괴에 미치는 영향에 대한 수치해석 연구)

  • Choa, Sung-Hoon;Jang, Young-Moon;Lee, Haeng-Soo
    • Journal of the Microelectronics and Packaging Society
    • /
    • v.25 no.1
    • /
    • pp.1-10
    • /
    • 2018
  • Recently, there has been rapid development in the field of flexible electronic devices, such as organic light emitting diodes (OLEDs), organic solar cells and flexible sensors. Encapsulation process is added to protect the flexible electronic devices from exposure to oxygen and moisture in the air. Using numerical simulation, we investigated the effects of the encapsulation layer on mechanical stability of the silicon chip, especially the fracture performance of center crack in multi-layer package for various loading condition. The multi-layer package is categorized in two type - a wide chip model in which the chip has a large width and encapsulation layer covers only the chip, and a narrow chip model in which the chip covers both the substrate and the chip with smaller width than the substrate. In the wide chip model where the external load acts directly on the chip, the encapsulation layer with high stiffness enhanced the crack resistance of the film chip as the thickness of the encapsulation layer increased regardless of loading conditions. In contrast, the encapsulation layer with high stiffness reduced the crack resistance of the film chip in the narrow chip model for the case of external tensile strain loading. This is because the external load is transferred to the chip through the encapsulation layer and the small load acts on the chip for the weak encapsulation layer in the narrow chip model. When the bending moment acts on the narrow model, thin encapsulation layer and thick encapsulation layer show the opposite results since the neutral axis is moving toward the chip with a crack and load acting on chip decreases consequently as the thickness of encapsulation layer increases. The present study is expected to provide practical design guidance to enhance the durability and fracture performance of the silicon chip in the multilayer package with encapsulation layer.

The 'Consequence Analysis' of Variables Affecting the Extent of Damage Caused by Butane Vapor Cloud Explosions (부탄가스 증기운폭발의 피해범위에 영향을 미치는 변수에 관한 고찰)

  • Char Soon-Chul;Choo Kwang-Ho
    • Journal of the Korean Institute of Gas
    • /
    • v.5 no.4 s.16
    • /
    • pp.1-7
    • /
    • 2001
  • This paper presents a 'consequence analysis' for vapor cloud explosions caused by heavy gas leakages from commercially used storage tanks at petrochemical plants. Particularly, this paper emphasizes on evaluating the results of various vapor cloud explosion accidents from Butane storage tanks. Also this paper analyses the impact of variables on the accidents in order to acquire the optimum conditions for variables. $SuperChems^{TM}$ Professional Edition was applied to analyse the impact (If atmospheric and other variables in the situation where vapor cloud continuously disperses from the ground level. Under the assumption that practical operating conditions are selected as a standard condition, and Butane leaks from the storage tank for 15 minutes, the results show that the maximum distance of LFL (Lower Flammable Limit) was 52 meters and overpressure by the vapor cloud explosion was 1 psi at 128.2 meters. It is observed that the impact of the variables on accidental Butane storage tank leakage mainly varied upon atmospheric stability, wind velocity, pipe line size, visible length, etc., and changes in the simulation result occurred as the variables varied. The maximum distance of the LFL (Lower Flammable Limit) increased as the visible length became shorter, the size of the leak became larger, the wind velocity was decreased, and the climatic conditions became more stable. Thus, by analysing the variables that influence the simulation results of explosions of Butane storage tanks containing heavy gases, I am presenting the most appropriate method for 'consequence analysis' and the selection of standards for suitable values of variables, to obtain the most optimal conditions for the best results.

  • PDF

Airborne Hyperspectral Imagery availability to estimate inland water quality parameter (수질 매개변수 추정에 있어서 항공 초분광영상의 가용성 고찰)

  • Kim, Tae-Woo;Shin, Han-Sup;Suh, Yong-Cheol
    • Korean Journal of Remote Sensing
    • /
    • v.30 no.1
    • /
    • pp.61-73
    • /
    • 2014
  • This study reviewed an application of water quality estimation using an Airborne Hyperspectral Imagery (A-HSI) and tested a part of Han River water quality (especially suspended solid) estimation with available in-situ data. The estimation of water quality was processed two methods. One is using observation data as downwelling radiance to water surface and as scattering and reflectance into water body. Other is linear regression analysis with water quality in-situ measurement and upwelling data as at-sensor radiance (or reflectance). Both methods drive meaningful results of RS estimation. However it has more effects on the auxiliary dataset as water quality in-situ measurement and water body scattering measurement. The test processed a part of Han River located Paldang-dam downstream. We applied linear regression analysis with AISA eagle hyperspectral sensor data and water quality measurement in-situ data. The result of linear regression for a meaningful band combination shows $-24.847+0.013L_{560}$ as 560 nm in radiance (L) with 0.985 R-square. To comparison with Multispectral Imagery (MSI) case, we make simulated Landsat TM by spectral resampling. The regression using MSI shows -55.932 + 33.881 (TM1/TM3) as radiance with 0.968 R-square. Suspended Solid (SS) concentration was about 3.75 mg/l at in-situ data and estimated SS concentration by A-HIS was about 3.65 mg/l, and about 5.85mg/l with MSI with same location. It shows overestimation trends case of estimating using MSI. In order to upgrade value for practical use and to estimate more precisely, it needs that minimizing sun glint effect into whole image, constructing elaborate flight plan considering solar altitude angle, and making good pre-processing and calibration system. We found some limitations and restrictions such as precise atmospheric correction, sample count of water quality measurement, retrieve spectral bands into A-HSI, adequate linear regression model selection, and quantitative calibration/validation method through the literature review and test adopted general methods.

Experimental Study on the Effect of Filter Layers on Pumping Capacity and Well Efficiency in an Unconfined Aquifer (자유면대수층에서 필터층이 취수량 및 우물효율에 미치는 영향에 대한 실험적 연구)

  • Song, Jae-Yong;Lee, Sang-Moo;Choi, Yong-Soo;Jeong, Gyo-Cheol
    • The Journal of Engineering Geology
    • /
    • v.27 no.4
    • /
    • pp.405-416
    • /
    • 2017
  • This study evaluated a model unconfined aquifer comprising a sand or gravel layer, a filter layer, a pumping well, and an observation well. The model was employed in step drawdown tests and then used to assess the permeability of each test tank. The optimal yield and well efficiency were then calculated. Evaluation of yield by step in sand layer filters of equal thickness gave optimized watering rates of 22.03 L/min in the double filter and 19.71 L/min in the single filter. The double filter's yield was 115.0% that of the single filter. A comparison of double and single filters, each 10 cm thick, showed the double filter to have a maximum yield of 182.7%. Yields for the gravel layer were 73.56 L/min for a double filter and 65.47 L/min for a single filter of the same thickness; the former value is 112.3% of that of the latter. Comparison of double and single filters with 10-cm-thick gravel layers revealed that the double filter had a maximum yield of 160.9%. Results for sand wells showed the double filter to have a maximum efficiency of 70.4% and the single filter to have a minimum efficiency of 37.1%. Gravel-layer well efficiencies were >66.5% for both double and single filters (each 30 cm thick), but only 22.5% for a 10-cm-thick single filter. This study confirms that permeability improved as the filter material became thicker; it also shows that a double filter has a higher yield and well efficiency than a single filter. These results can be applied to the practical design of wells.

Demonstration-scale Offshore CO2 Storage Project in the Pohang Basin, Korea (포항분지 해상 중소규모 CO2 저장 실증연구)

  • Kwon, Yi Kyun
    • The Journal of Engineering Geology
    • /
    • v.28 no.2
    • /
    • pp.133-160
    • /
    • 2018
  • $CO_2$ storage is a very important technology for reduction of greenhouse gas emissions and has been considered as almost the only viable and effective option for immediate large-scale $CO_2$ sequestration. Small-scale demonstration project for offshore $CO_2$ storage in the Pohang Basin is the transitional stage R&D program for technological preparation of large-scale $CO_2$ storage project in Korea. Through the extensive exploration research for prospective $CO_2$ storage sites, the offshore strata in the Pohang Basin was recommended for the storage formation of the small-scale demonstration project. The Pohang Offshore Storage Project launched at 2013, and has accomplished the technical demonstration and technological independence in a wide range of $CO_2$ storage technology, such as geophysical exploration, storage site characterization, storage design, offshore platform construction, injection-well drilling and completion, deployment of injection facility, operation of $CO_2$ injection, and $CO_2$ monitoring. The project successfully carried out $CO_2$ test injection in early 2017, and achieved its final goal for technical development and demonstration of $CO_2$ storage in Korea. The realization of $CO_2$ injection in this project is the measurable result and has been recorded as the first success in Korea. The Pohang Offshore Storage Project has a future plan for the continuous operation of $CO_2$ injection and completion of $CO_2$ monitoring system. The project has provided in-house technical and practical expertises, which will be a solid foundation for the commercial-scale $CO_2$ storage business in Korea. Additionally, the project will help to secure national technical competitiveness in growing international technology market for $CO_2$ storage.

Developments of Water Treatment System by Biological Fluidized Bed for Water Reuse Aquaculture (생물학적 유동층을 이용한 어류양식 순환수의 처리씨스템 개발)

  • LEE Ki-Wan
    • Korean Journal of Fisheries and Aquatic Sciences
    • /
    • v.26 no.4
    • /
    • pp.380-391
    • /
    • 1993
  • The experimental study was made to propose the treatment method of wastewater in the high-density fish culture system. The BOD to COD ratios of effluents were almost same to 0.65 in the eel-farm, but were various in the farm rearing together with tilapia etc. A BOD rate curve of the eel-farm effluent could be described mathematically by the equation, $BODu=14.1(1-10^{-0.222t})+30.9(1-10^{-0.035(t-8)})$. Nitrification in Biological Fluidized Bed(BFB) system to treat the fish-farm wastewater could be reduce ammonium level up to $65{\sim}79\%$ when ammonium loading rates were between 0.014 and 0.075g $NH_4/g$ BVS-day. Nitrification efficiency was decreased by organic matters in the wastewater when ammonium loading was low(0.014 g $NH_4/g$ BVS-day). T-N removal ratios were decreased to increase loading in denitrification process, because of low C/N ratio. Based on much higher biological mass concentrations, BFB system takes many advantages of a practical viewpoint, such as stability of treatment efficiency and reduction of necessary site area for the facility, as compared with conventional treatment systems.

  • PDF

A study on applying specialized vocational high schools program and development of Gyeonggi innovative education project (경기 혁신교육지구 사업의 발전방향과 특성화(전문계)고 프로그램적용 방안연구)

  • Chang, Eun-Young;You, Hyung-Jin
    • The Journal of Korean Institute for Practical Engineering Education
    • /
    • v.3 no.1
    • /
    • pp.1-8
    • /
    • 2011
  • In this paper, as a new educational cooperation model, seeking the problems and the directions of progress on GPOE(Gyeonggi Provincial Office of Education)'s innovational education district project, recognizing the various points of issue of SVHS(specialized vocational high schools) faced now, suggesting the contents and standards of the program as measures of enhancing competitiveness of SVHS, analyzing the strengths and weaknesses of project of innovational education district and finding the plans for progress. According to the result of the advanced study and analysis, it shows that the aid as well as the supporting object of helping the SVHS's students find a job don't reach a certain level. As the aid supports across the general elementary and secondary schools, it tends to show much more emotional software-based support required by elementary school, middle school and general high school as universal education welfare rather than hardware-based support required by SVHS. Despite the competent evaluation on the survey about the supporting method from SVHS's parents teachers and students, the survey includes that teachers who ask the balancing support are increasing, some students suspect its effect of education and some parents as a residential position ask the regional growth rather than education So there are a lot of confusions among the teachers, students and parents yet. To overcome these problems, we ensure the internal stability of local education community and GPOE and local government get out large scale constructions with trust and belief to make a revolution of public education in supporting the administrative task and finance and to accomplish the program that best suits our SVHS's state to be supported without dividing educational software and hardware, should reflect the demand of field by for expert group being built and attended when build the local revolution community. Also plan to make full use of local human and property infrastructure should be added. To this end, as programs to build a pool of guest lecturers are provided to teachers who carry out innovative education programs, we seek the reformations to give students opportunities to widen participation in other school programs.

  • PDF

Gadoteridol's Signal Change according to TR, TE Parameters in T1 Image (T1영상에서 TR, TE 매개변수에 따른 Gadoteridol의 신호강도 변화)

  • Jeong, Hyun Keun;Jeong, Hyun Do;Nam, Ki Chang;Kim, Ho Chul
    • Journal of the Institute of Electronics and Information Engineers
    • /
    • v.52 no.9
    • /
    • pp.117-124
    • /
    • 2015
  • In this paper, we introduce how to control TR, TE physical MR parameters for managing $H_1$ spin's SI(Signal Intensity) which is combined with gadolinium following administration MR agent in T1 effect for diagnostic usefulness. we used MRI phantom made with 0.5 mol Gadoteridol. This phantom was scanned by FSE sequence with different TR, TE parameters. In this study, to make T1 effect, TR was 200, 250, 300, 350, 400, 450, 500, 550, 600 msec. In addition to, TE was 6.2, 12.4, 18.6, 21.6 msec. The results were as follows ; Each RSP(Reaction Starting Point) was 100, 50, 40, 30 mmol in TE 6.2, 12.4, 18.6, 21.6 msec being irrelevant to TR. In MPSI(Max Peak Signal Intensity), 4 mmol was showed in TR 200 msec while peak signal was decreased to low concentration mol in TR 250-600 msec. In terms of RA(Reaction Area), the highest SI was TE 6.2 msec in TR 200-600msec. According to the study, we are able to recognize it is possible to control enhance rates by managing TR and TE of MR parameters; moreover, we expect that enhanced T1 image in MR clinical field can be performed in a practical way with this quantitative data.

A Study on an Effect that Resources and Capabilities of Lifelong Educational Institutions have on Learning Performances (대학 평생교육기관의 자원과 역량이 학습성과에 미치는 영향에 관한 연구)

  • Jeong, Jin Tae;Kim, Joo Il
    • The Journal of Korean Institute for Practical Engineering Education
    • /
    • v.2 no.2
    • /
    • pp.120-136
    • /
    • 2010
  • As there has recently been a rapid increase in importance of lifelong study, the number of learners participating in lifelong educational programs is increasing geometrically and lifelong educational institutions turned out to be the best one where everyone wants to study. Hereupon, aimed at team leaders managing the whole nation lifelong institutions and teachers interacting briskly with learners, we tried to research and analyze main cause affecting performances of lifelong educational institutions of university in this study based on Resource Based View and Dynamic Capability Theory for continuous development of lifelong educational institutions and securement of the competition. The contents and results of this study run as follows First, We tried to investigate the relation between resources and performances of lifelong educational institutions of university as contents and results of this study. The results were analyzed that material resources like an easy accessibility, superiority of facilities and teachers' excellence of lifelong educational institutions have an beneficial influence. Second, We tried to understand a leading cause affecting Dynamic Capabilities of lifelong educational institutions. The analyzed results were that material and human resources like easy accessibility, superiority of facilities, superiorities of teachers and director's empowering readership as a superior and organizational culture(autonomy, interaction) affect Dynamic Capabilities. These results could be understood that lifelong educational institution characteristics of university are well reflected. Third, We tried to find that even though elements of Resource Based view are surely important, Dynamic Capabilities of the organization are more important for continuous development and growth of lifelong educational institutions. Upon investigation, we found that there were mediating effectiveness in relations between Absorptive Capability and Innovative Capability which are Dynamic Capabilities and performances. Like preceding, there wes also mediating effectiveness in relations between empowering and organizational culture(autonomy, interaction) of a superior. And to conclude, superiority of resources could contribute to developing lifelong educational institutions to some degree but considering features of lifelong educational markets rapidly changed, Dynamic Capabilities of organization are more important for continuous growth and expensive preferability.

  • PDF