• Title/Summary/Keyword: energy index

Search Result 2,329, Processing Time 0.037 seconds

Reliability analysis of shallow tunnel with surface settlement

  • Yang, X.L.;Li, W.T.
    • Geomechanics and Engineering
    • /
    • v.12 no.2
    • /
    • pp.313-326
    • /
    • 2017
  • Based on the reliability theory and limit analysis method, the roof stability of a shallow tunnel is investigated under the condition of surface settlement. Nonlinear Hoek-Brown failure criterion is adopted in the present analysis. With the consideration of surface settlement, the internal energy and external work are calculated. Equating the rate of energy dissipation to the external rate of work, the expression of support pressure is derived. With the help of variational approach, a performance function is proposed to reliability analysis. Improved response surface method is used to calculate the Hasofer-Lind reliability index and the failure probability. In order to assess the validity of the present results, Monte-Carlo simulation is performed to examine the correctness. Sensitivity analysis is used to estimate the influence of different variables on reliability index. Among random variables, the unit weight significantly affects the reliability index. It is found that the greater coefficient of variation of variables lead to the higher failure probability. On the basis of the discussions, the reliability-based design is achieved to calculate the required tunnel support pressure under different situations when the target reliability index is obtained.

Assessment of Remote Sensing-based Hydrological Drought Indices (인공위성영상 기반의 수문기상변수를 활용한 수문학적 가뭄지수 개발 및 평가)

  • Sur, Chanyang;Park, Seo-Yeon;Kim, Tae-Woong;Lee, Joo-Heon
    • Proceedings of the Korea Water Resources Association Conference
    • /
    • 2018.05a
    • /
    • pp.22-22
    • /
    • 2018
  • 본 연구에서는 수문학적 가뭄을 분석하기 위해 두가지 지수를 개발하여 소개하고자 한다. 첫번째는, 물수지식을 기반으로 산정된 Water Budget-based Drought Index(WBDI)로 강우와 증발산의 차이를 이용하여 산정한다. 두 번째는 에너지 수지식을 기반으로 산정된 Energy-based Water Deficit Index(EWDI)로 에너지 수지 기반의 증발산, 태양복사에너지와 토양수분 등을 이용하여 산정한다. 두가지 지수 모두 인공위성 영상 자료를 활용하였다. WBDI 산정을 위한 강수량 자료는 Tropical Rainfall Measuring Mission(TRMM)과 Global Precipitation Mission(GPM)를 활용하였으며, 증발산 자료는 Moderate Resolution Imaging Spectroradiometer (MODIS) 자료를 활용하였다. EWDI 산정에 필요한 입력자료는 모두 MODIS 자료를 활용하였다. 산정된 두 가뭄지수의 수문학적 가뭄 분석을 위해 자연유출지점인 6개 지점을 선정하여 유출량 자료와 비교하였다. 유출량 자료를 활용하여 Error matrix 기법을 적용하여 두 수문학적 가뭄지수의 우리나라에서의 적용성을 파악하였다.

  • PDF

A Study on Improvement for Greenship Certification Scheme to Achieve Net-Zero (탄소중립을 위한 친환경선박 인증제도의 개선방향에 관한 연구)

  • Junkeon, Ahn
    • Journal of the Society of Naval Architects of Korea
    • /
    • v.59 no.6
    • /
    • pp.372-384
    • /
    • 2022
  • Total shipping accounts for 2.9 % of the annual average percentage of global anthropogenic GHG emissions. The International Maritime Organization implements EEDI (Energy Efficiency Design Index), Energy Efficiency eXisting-ship Index (EEXI), and Carbon Intensity Indicator (CII) as regulatory frameworks for shipping decarbonization. The Republic of Korea has enforced the Act on Development and Popularization of Greenship from 2020 and publicly announced the 1st national plan which was named 『2030 Greenship-K Promotion Strategy』 for the activation of a greenship market. The Greenship Certification Scheme is going on for the sustainability of Korean shipbuilding and shipping industries, to secure clean maritime environments, as well as to contribute to the national economy. Greenship Certification guarantees the credit of such eco-friendly technologies and products for shipping. The certification is going to be the basis of industrial competitiveness in coastal and international shipping. This study investigates an existing certification process, identifies the limitations, and proposes the process improved with several case studies. The improved certification scheme may have rationality for Net-zero with regard to climate alignment.

A Study on Realization Method of Low Carbon School Building (저 탄소 학교건축물 구현 방안에 관한 연구)

  • Tae, Sung-Ho;Cho, Young-Sang;Shin, Sung-Woo;Lee, Seung-Min;Meang, Joon-Ho
    • The Journal of Sustainable Design and Educational Environment Research
    • /
    • v.9 no.2
    • /
    • pp.30-37
    • /
    • 2010
  • This study purposed realization and a phase reduction of school building $CO_2$ emissions. Accordingly selected standard school buildings and evaluated life cycle environmental load($CO_2$). This study proposed Green building technology which separated design sector, energy sector, afforestation sector for carbon-neutral city school buildings realization of M-city. As a result, elementary, middle and high schools of M-city built in the year 2013 were required that design sector was Energy Performance Index(EPI) 75 point and energy sector was solar installations more than 25% of the power usage, Solar systems installed more than 10% of total gas consumption and the area of afforesting more than 35% of the ecological area to achieve 30% $CO_2$ reduction compared to the Respectively standard school buildings.

Revaluation of Solar Radiation Resources in Korean Peninsular (한반도 태양에너지 자원의 재평가)

  • Jo, Dok-Ki;Yun, Chang-Yeol;Kim, Kwang-Deuk;Kang, Young-Heack
    • 한국태양에너지학회:학술대회논문집
    • /
    • 2009.11a
    • /
    • pp.50-55
    • /
    • 2009
  • Images taken by geostationary satellite may be used to estimate solar irradiance fluxes at earth's surface. It is based on the empirical correlation between a satellite derived cloud index and the irradiance at the ground. For the validation, estimated solar radiation fluxes are compared with observed solar radiation fluxes at 16 sites over the Korean peninsular from January 1982 to December 2007. Estimated solar radiation fluxes show reliable results for estimating the global radiation with average deviation of -7.58 to +3.8% from the measured values and the yearly averaged horizontal global insolation of Korean peninsula was turned out to be $3.59kW/m^2/day$.

  • PDF

Study on Thermal Performance Characteristics of CPC System Depending on Weather Conditions and Capacity of Heat Storage Tank (기상 조건과 축열조 용량에 따른 복합 포물형 집열기(CPC) 시스템의 열적 성능 특성에 관한 연구)

  • LIM, SOK-KYU;JUNG, YOUNG GUAN;KIM, KYOUNG HOON
    • Journal of Hydrogen and New Energy
    • /
    • v.30 no.1
    • /
    • pp.58-66
    • /
    • 2019
  • Static compound parabolic collectors (CPCs) have advantages such as ease for fabrication and lower cost compared with other concentrating collectors. In this study, thermal performance analysis of CPC employing heat storage tank was carried out. The clearness index and capacity of heat storage tank are taken as the main parameters for numerical simulation. The effects of the parameters on the hourly and daily system performances ncluding the useful energy, heat loss, and collector efficiency were numerically investigated. Results showed that the system has a potential for efficient recovery of solar thermal energy.

Optimized stiffener detailing for shear links in eccentrically braced frames

  • Ozkilic, Yasin O.
    • Steel and Composite Structures
    • /
    • v.39 no.1
    • /
    • pp.35-50
    • /
    • 2021
  • Eccentrically braced frames (EBFs) are utilized as a lateral resisting system in high seismic zones. Links are the primary source of energy dissipation and they are exposed to high deformation, which may lead to buckling. Web stiffeners were introduced to prevent buckling of shear link. AISC 341 provides the required vertical stiffeners for a shear link. In this study, different stiffener configurations were examined. The main objective is to improve the behavior of short links using different stiffener configurations. Pursuant to this goal, a comprehensive numerical study is conducted using ABAQUS. Shear links with different stiffener configurations were subjected to cyclic loading using loading protocol mandated by AISC 341. The results are compared in terms of energy dissipation and shear capacities and rupture index. The proposed stiffener configurations were further verified with different link length ratios, I-shapes and thickness of stiffener. Based on the results, the stiffener configuration with two vertical and two diagonal stiffeners perpendicular to each other is recommended. The proposed stiffener configuration can increase the shear capacity, energy dissipation capacity and the ratio of energy/weight up to 27%, 38% and 30%, respectively. Detailing of the proposed stiffener configuration is presented.

A Study on Nutrient Intakes, Glycemic Index, and Glycemic Load according to Obesity Index in Elementary School Students (남녀 초등학생의 비만도에 따른 영양소 섭취 및 Glycemic Index, Glycemic Load에 관한 연구)

  • Bae, Yun-Jung;Choi, Mi-Kyeong
    • Journal of the East Asian Society of Dietary Life
    • /
    • v.21 no.2
    • /
    • pp.174-184
    • /
    • 2011
  • The purpose of this study was to evaluate nutrients intakes, glycemic index (GI), glycemic load (GL) according to obesity index in elementary school students. The study subjects included 229 elementary school students (boys=108, girls=121) who were divided into 3 groups consisting of an underweight group (obesity index<-10%, n=58), a normal weight group (10%${\leq}$ obesity index<10%, n=130) and an overweight group (obesity index${\geq}$10%, n=41) by their obesity index. The nutrient and food intakes data obtained by a 3-day food record were analyzed. Daily dietary GI and GL values were calculated from the 3-day food record. The average age of the subjects was 11.9 years. The mean daily energy intake was 2,186.8 kcal in the underweight group, 2,123.5 kcal in the normal weight group, and 2,174.2 kcal in the overweight group. The intakes of calcium and animal calcium per 1,000 kcal in the overweight group were significantly lower than in the underweight and normal weight groups (p<0.01, p<0.05), and fruit, egg and milk intakes in the overweight group were lower than those in the underweight group (p<0.05, p<0.05, p<0.05). The mean daily dietary GI of the underweight, normal weight, and overweight groups were 67.7, 68.4 and 69.5, respectively (p<0.05). The mean daily dietary GL of the underweight, normal weight, and overweight groups were 212.8, 208.1 and 213.3, respectively. The major food source of dietary GI and GL in the three groups was rice. Other major food sources of dietary GI were croquettes, hand-rolled noddle soups, instant noddles, milk, and rice cake. Dietary GI was not significantly correlated with weight, obesity or body mass index, when adjusted for energy, carbohydrate, and dietary fiber. However, GL adjusted to energy, carbohydrate and dietary fiber tended to correlate with obesity index (r=0.126, p=0.059). These results suggest that dietary GI and GL have possibility affecting obesity-related indicators in elementary school students.

Effect of Polyethylene Glycol Molecular Weight and NCO Index on Properties of the Hydrophilic Reactive Hotmelt Polyurethane Adhesives (Polyethylene Glycol의 분자량 및 NCO index의 변화에 따른 Hydrophilic Reactive Hotmelt Polyurethane의 물성 변화)

  • Han, Young Chul;Kim, Dack Han;Oh, Kyung Seok;Shin, Hyeon Jeong;Yang, Jeong Han;Jeong, Han Mo
    • Textile Coloration and Finishing
    • /
    • v.30 no.2
    • /
    • pp.90-97
    • /
    • 2018
  • Hydrophilic reactive hot-melt polyurethane adhesive(HRHA) using a hydrophilic polyol having different molecular weight and NCO index was synthesized. This HRHA was synthesized using Polyethylene glycol(PEG) as a hydrophilic polyol, Polypropylene glycol(PPG) and Polycaprolactone diol(PCL) as hydrophobic polyols, and Methylene diphenyl diisocyanate(MDI) as an isocyanate. The changes in IR spectrum, viscosity and thermal properties of HRHA with different PEG molecular weights and NCO index were investigated, and the tensile strength and elongation of the HRHA casting film and the peel strength, moisture permeability and water pressure of the HRHA coated fabric were confirmed. In this experiment, as the molecular weight of PEG and NCO index increased, the adhesive strength, tensile strength, elongation and moisture permeability was increased but viscosity and Tg was decreased.

Estimation of Rock Erodibility due to Energy Dissipation of Inflow Passing through the Sluice Gate of Seadike (배수갑문 유입수류의 에너지 감쇠에 따른 암석 침식 가능성 추정)

  • Jo, Jin-Hun;Park, Yeong-Jin;Park, Sang-Hyeon
    • Journal of Korea Water Resources Association
    • /
    • v.33 no.2
    • /
    • pp.237-245
    • /
    • 2000
  • Sihwa seadike is originally designed to control the water level In lake Sihwa. However the sluice gate is being operated everyday to preserve the water quality of lake. Due to the frequent operation of gates the bottom of drainage canal which is composed of weathered rock and soft rock is being scoured. Recently the bottom in the front area of apron was protected by putting underwater concrete. This study is carried out to understand the hydraulic situation for protection, and to estimate the trend of scouring by comparing between energy dissipation and registance of bottom rock. Annandale(1995) introduced the erodibility index theory, and suggested a criteria to judge the erodibility of rock through the relation between the erodibility index and energy dissipation. Determenation of erodibility index of rock is based on the results of sample core analysis, and the energy dissipation of flow is calculated from the estimation of total head on the scale model. These two values are plotted on the criteria, and the erodibility of rock is determined.

  • PDF