• Title/Summary/Keyword: Carrying capacity

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Estimation of Carrying Capacity by Food Availability for Farming Oysters in Goseong Bay, Korea (먹이가용성에 의한 고성만의 굴 양식장 수용력)

  • Lee, Sang-Jun;Jeong, Woo-Geon;Cho, Sang-Man;Kwon, Jung No
    • The Korean Journal of Malacology
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    • v.32 no.2
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    • pp.83-93
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    • 2016
  • For the continuous stable production of oyster, estimation of food availability (F) was carried out in Goseong Bay, south of coast Korea. Primary productivity ranged from 0.07 to $0.44gC/m^2/day$ (average $0.25gC/m^2/day$), lowest in July and highest in January. The distribution of primary productivity at Goseong Bay showed the pattern of "high in the south and low in the north." Food availability (F) was $F{\leq}0$, indicating insufficient food supply, from August to November and F > 0 from January to April. Continuous insufficient food supply was observed at 18 oyster farms in the southern part of the bay and 4 in its northern part. Mortality at the oyster farms was 56% on the average, and around 58% of death occurred during November when food supply was insufficient. The optimal population of cultured oyster per unit flow area was calculated to be $110-115indiv./m^2$ (198-201 indiv./string). When the sea area was divided into 3 regions (A, B, C) according to carrying capacity, the carrying capacity of (A) regions was $52-53indiv./m^2$ (93-95 indiv./string), (B) regions was $142-144indiv./m^2$ (255-259 indiv./string), and (C) regions was $198-202indiv./m^2$ (356-363 indiv./string). In particular, (A) regions showed extremely low productivity. For continuous stable oyster farming at Goseong Bay, it is necessary to control point and non-point source pollution through continuous environmental monitoring and to adjust harvest according to the base carrying capacity during the season of high water temperature.

Direction for Improving Management Model based on Carrying Capacity for Managing natural resources in ecotourism area : Focused on Getz, LAC, VIM and VERP (생태관광지역 자연자원 관리를 위한 수용력 기반 관리모델 개선방향 : Getz, LAC, VIM, VERP 관리모델을 중심으로)

  • Park, Hong Chul;Oh, Choong Hyeon
    • Journal of Environmental Policy
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    • v.13 no.4
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    • pp.107-133
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    • 2014
  • The eco-tourism has caused a variety of problems between use and conservation. The situation requires introduction of scientific management techniques, such as controlling the number of visitors to the destination and identifying appropriate carrying capacity. Getz, LAC, VIM and VERP have been developed for this purpose and they are the management model based on carrying capacity that have been explored for introduction and application in Korea. However, it is necessary to modify and supplement the management model to suit the purpose of ecotourism characteristics and the status of ecotourism in Korea. Therefore, we identified the problems of the existing management model and presented three improvements. strengthen the interdependent linkages between carrying capacity and the management goals; improve the tourism opportunity distribution model; improve the phased management. It will help many ecotourism sites to effectively manage the impacts of visitors in Korea with a minimum amount of effort and costs.

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A Study on Load Carrying Capacity of Ancient Stone Arch Bridge (고대 석조아치교량의 내하력에 관한 연구)

  • 정형식;황영철
    • Geotechnical Engineering
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    • v.8 no.4
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    • pp.31-40
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    • 1992
  • The arch of an ancient stone arch bridge consists of blocky stone blocks. For the purpose of estimation of load carrying capacity of a stone bridge, the mechanically frail discontinuities between stone blocks should be taken account of. Since the current way of analysis regards the stone arch as a continuous member, the characteristic of discontinuties is not considered. In this paper, an ancient stone arch bridge is analyzed and load carrying capacity is estimated by Finite Element Method with the discontinuties between blocks being modelled as interface elements. From the result of the study, it is shown that the load carrying capacity of a stone arch bridge is dependent of friction angle and shear stiffness between arch blocks rather than compressive strength of arch block itself and the stone arch bridge of granite is more influenced by shear stiffness than friction angle. The load carrying capacity of HONG bridge of HEUNG GUK temple analyzed in this paper is estimated as that of a third grade bridge.

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A Conversion of Load Carrying Capacity for Existing Steel Box Girder Bridge Based on Limit State Design Method (한계상태설계법에 의한 기존 강박스거더교의 내하력 환산)

  • Noh, Dong-Oh;Kyung, Kab-Soo;Park, Jin-Eun
    • Journal of the Korea institute for structural maintenance and inspection
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    • v.22 no.6
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    • pp.89-96
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    • 2018
  • Bridge structures are a socially important infrastructure and safety management of bridges during the public service period is important. Steel box girder bridges, which account for a large percentage of road bridges, have been designed by allowable stress design method(ASD) and load carrying capacity have been evaluated using ASD. Although design specification has recently been changed to limit state design method(LSD), in most cases, ASD is still used for load carrying capacity evaluation. In this study, the two design methods were used to compare the results of a load rating factor evaluation on a number of bridges, and we are going to find out how to convert the existing rating factor by ASD into rating factor by LSD. The results of this study are expected to can be used as a basis for determining the need for reinforcement and evaluating load carrying capacity by LSD in bridge maintenance.

A Experimental Study on the Static Strengthen Effect of Bridge Deck Strengthened with GFS (GFS로 성능향상된 교량 바닥판의 정적 보강효과)

  • 심종성;오홍섭;류승무;박성재
    • Proceedings of the Korea Concrete Institute Conference
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    • 2001.11a
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    • pp.739-744
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    • 2001
  • The concrete bridge deck is quitely required to be replaced or strengthened due to decreasing load carrying capacity. In this study, to increase load capacity of the reinforced concrete slab, bridge deck is reinforced with the glass fiber sheets. they are examined on the strengthen effect and the static behavior, This paper considers relation of load-displacement and strain-distance. The static behavior of the slab strengthened is represented to maximum load. Owing to that, they are examined on increasing load carrying capacity of reinforced bridge deck and strengthen effect about on the crack.

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A Study on the Parallel Line Pivoted Pad Thrust Bearing (평행선 지지식 추력베어링에 관한 연구)

  • 이경우;김종수;제양규
    • Tribology and Lubricants
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    • v.15 no.1
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    • pp.24-28
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    • 1999
  • This paper describes a new pivoting technique to improve bearing performance in pivoted pad thrust bearings. This new technique adjusts the pivot line in a line pivoted pad thrust bearing to be parallel to the trailing edge of a sector shaped pad. Bearing performance factors such as load carrying capacity, frictional torque and flow rate are numerically investigated for conventional point-pivoted and line-pivoted pads and for the new parallel-line pivoting technique. It is shown that the load carving capacity can be maximized with the new technique.

Seismic performance of exterior R/C beam-column joint under varying axial force

  • Hu, Yanbing;Maeda, Masaki;Suzuki, Yusuke;Jin, Kiwoong
    • Structural Engineering and Mechanics
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    • v.78 no.5
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    • pp.623-635
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    • 2021
  • Previous studies have suggested the maximum experimental story shear force of beam-column joint frame does not reach its theoretical value due to beam-column joint failure when the column-to-beam moment capacity ratio was close to 1.0. It was also pointed out that under a certain amount of axial force, an axial collapse and a sudden decrease of lateral load-carrying capacity may occur at the joint. Although increasing joint transverse reinforcement could improve the lateral load-carrying capacity and axial load-carrying capacity of beam-column joint frame, the conditions considering varying axial force were still not well investigated. For this purpose, 7 full-scale specimens with no-axial force and 14 half-scale specimens with varying axial force are designed and subjected to static loading tests. Comparing the experimental results of the two types of specimens, it has indicated that introducing the varying axial force leads to a reduction of the required joint transverse reinforcement ratio which can avoid the beam-column joint failure. For specimens with varying axial force, to prevent beam-column joint failure and axial collapse, the lower limit of joint transverse reinforcement ratio is acquired when given a column-to-beam moment capacity ratio.

Estimating the Carrying Capacity of a Coastal Bay for Oyster Culture -II. The Carrying Capacity of Geoie-Hansan Bay- (굴 양식수역의 환경용량 산정 -II. 거제 · 한산만의 환경용량-)

  • Park Jong Soo;Kim Hyung Chul;Choi Woo Jeung;Lee Won Chan;Kim Dong Myung;Koo Jun Ho;Park Chung Kil
    • Korean Journal of Fisheries and Aquatic Sciences
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    • v.35 no.4
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    • pp.408-416
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    • 2002
  • A 3D hydrodynamic-ecological coupled model was applied to estimate carrying capacity in Geoje-Hansan Bay where is one of the most important oyster culturing grounds in Korea. We considered the carrying capacity as the difference between food supply to the oysters and food demand, considering monthly difference of the actual growth. The food supply to the system was determined from the results of the model simulation (tidal exchange and chlorophyll $\alpha$) over the culturing period from September to May of the following year. The food demand was estimated from the food concentration (chlorophyll $\alpha$) multiple the filtration rate of oysters that is considered monthly different growth rate of oysters and food concentration. The values of carrying capacity for the system varied from 6.1 ton/ha (minimum carrying capacity) in february to 14.91 ton/ha (maximum carrying capacity) in April of marketable size oysters (>4 g wet-tissue weight) depending on temporal variations in the food supply. The oyster production calculated from present facilities was 9 ton/ha in wet-tissue weight in Geoje-Hansan Bay. This value corresponded to $60\%$ of maximum carrying capacity of the system. The optimal carrying capacity without negatively affecting on oyster production was 5.5 ton/ha when calculated from annual statistic data and 6.1 ton/ha when determined by this study. These results suggest that it must be reduced $32\%$~$39\%$ of oyster facilities in the system.

Analysis of Capacity Factors and Capacity Credits for Wind Turbines Installed in Korea (국내 풍력발전 설비의 이용률과 용량크레딧 분석)

  • Paik, Chunhyun
    • Journal of the Korean Solar Energy Society
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    • v.39 no.4
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    • pp.79-91
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    • 2019
  • The capacity credit (CC) is a key metric for mid- to long-term power system capacity planning. The purpose of this study is to estimate the CCs of domestic wind turbines. Based on hourly capacity factor (CF) data during the seven years from 2011 to 2017, the new so-called probabilistic CF scheme is introduced to effectively reflect the variability of CFs on CC estimation. The CCs are then estimated through the CF-based method and the ELCC (Effective Load Carrying Capability) method reflecting the probabilistic CF scheme, and the results are compared. The results show that the CC value 0.019 for domestic wind turbines proposed in the $8^{th}$ Basic Plan for Electricity Supply and Demand corresponds to the CC with a confidence level slightly lower than 95%.

Environmental Impact and Allowable Density Using the Rural Residential Density Matrix (주거밀도모형을 이용한 환경영향분석과 수용능력 산출)

  • Kim, Myungjin
    • Journal of Environmental Impact Assessment
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    • v.12 no.3
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    • pp.151-160
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    • 2003
  • Analysis of carrying capacity and site suitability by the systematic application of environmental information an provide a basis for implementing environmentally sensitive and sustainable resource development policies. Based on the availability of public services and environmental and site-specific constraints, a Rural Residential Density Matrix was applied in Santa Cruz County, California, USA to assess the development potential of rural land parcels since 1980. In one case, the Matrix was applied to calculate the allowable development density on a site in Lompico planned for use as a Buddhist retreat center. These calculations revealed higher environmental sensitivity and lower carrying capacity than projected in the proposed plan. Under the constraints of the county's minimum acreage policies and insufficient developable land, the developer cancelled the proposed plan. This example suggests that application of the Matrix at the concept development stage would increase the effectiveness of the prior environmental review and environmental impact assessment (EIA) system in Korea.