• Journal of Forest and Environmental Science
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• 제34권1호
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• pp.31-45
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• 2018

At present the biodiversity of the riparian forest is under threat due to various anthropogenic pressures. Hence study was conducted along the three unprotected zones of riparian forest in Dikhu river, Nagaland, north-east India in order to compared the diversity, distribution and population structure of riparian trees. In each zone $100{\times}100m^2$ plot were marked and subdivided into 20 plots of $10{\times}10m^2$. 10 plots on each side of the river were taken randomly covering 0.02 ha. Only tree with dbh ${\geq}10cm$ and dbh above 1.5 m above ground level were recorded as individual species. A total of 29 tree species belonging to 18 families were recorded from the three zones of the river. Tree species richness was highest at the middle zone (19) followed by upper (14) and lower zone (7). The most abundant species and family recorded at upper, middle and lower zones were Melia azaderach of Euphorbiaceae ($380\;stems\;ha^{-1}$), Terminalia chebula of Euphorbiaceae ($432.5\;stems\;ha^{-1}$) and Duabanga grandiflora of Lythraceae ($365\;stems\;ha^{-1}$) respectively. The ranges of diversity indices observed in the three zones were: Shannon-Wiener index (1.25-0.73), Simpson diversity index (0.42-0.93), Evenness index (0.47-0.37) and Index of co-dominance (0.75-0.94). Rest of other indices were also estimated and compared. Distribution of trees shows the contagious pattern common in the upper and middle zones and regular in the lower zone. The girth size class analysis demonstrated that the riparian forest is in less mature succession stage. This study emphasize the need for management and conservation of riparian forest by developing policy to declare the riparian zone as protected area to prevent further degradation and loss of biodiversity from these unregulated zones along the river.

• 생물환경조절학회지
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• 제9권4호
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• pp.207-211
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• 2000

지온이 포도의 생육에 미치는 영향을 조사하기 위하여 노지용으로 많이 재배되는 캠벨얼리와 시설포도인 블랙올림피아를 공시하여 지온을 1$0^{\circ}C$, 15$^{\circ}C$, 2$0^{\circ}C$, $25^{\circ}C$로 조절하여 재배하고 생육조사와 더불어 광합성 속도 및 식물체의 무기성분함량을 조사한 결과를 요약하면 다음과 같다. 지온 20~$25^{\circ}C$에서 품종에 관계없이 엽중, 경중, 근중을 비롯한 모든 생육이 좋았다. 광합성 속도와 엽록소 함량은 2$0^{\circ}C$구에서 가장좋았다. 지온이 높아질수록 줄기와 뿌리인 인산, 칼륨, 석회의 함량이 많았다.

• Steel and Composite Structures
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• 제8권3호
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• pp.243-264
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• 2008

This paper details a testing facility ("NATURAL FIRE FACILITY") that allows closely-controlled experimental testing on full-scale sub-frames while reproducing the spatially transient temperature conditions measured in real fires. Using this test facility, an experimental investigation of six steel sub-frames under a natural fire was carried out at the Department of Civil Engineering of the University of Coimbra. The main objective of these tests was to provide insight into the influence of these connection types on the behaviour of steel sub-structures under fire. The experimental layout is defined by two thermally insulated HEA300 columns and an unprotected IPE300 beam with 5.7 m span, supporting a composite concrete slab. Beam-to-column connections are representative of the most common joint type used on buildings: welded joints and extended, flush and partial depth plate. Finally, the available results are presented and discussed: evolution of the steel temperature; development of displacements and local deformations and failure modes on the joints zone.

• Structural Engineering and Mechanics
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• 제30권6호
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• pp.713-732
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• 2008

Serviceability and durability of the concrete members can be seriously affected by the corrosion of steel rebar. Carbonation front and or chloride ingress can destroy the passive film on rebar and may set the corrosion (oxidation process). Depending on the level of oxidation (expansive corrosion products/rust) damage to the cover concrete takes place in the form of expansion, cracking and spalling or delamination. This makes the concrete unable to develop forces through bond and also become unprotected against further degradation from corrosion; and thus marks the end of service life for corrosion-affected structures. This paper presents an analytical model that predicts the weight loss of steel rebar and the corresponding time from onset of corrosion for the known corrosion rate and thus can be used for the determination of time to cover cracking in corrosion affected RC member. This model uses fully the thick-walled cylinder approach. The gradual crack propagation in radial directions (from inside) is considered when the circumferential tensile stresses at the inner surface of intact concrete have reached the tensile strength of concrete. The analysis is done separately with and without considering the stiffness of reinforcing steel and rust combine along with the assumption of zero residual strength of cracked concrete. The model accounts for the time required for corrosion products to fill a porous zone before they start inducing expansive pressure on the concrete surrounding the steel rebar. The capability of the model to produce the experimental trends is demonstrated by comparing the model's predictions with the results of experimental data published in the literature. The effect of considering the corroded reinforcing steel bar stiffness is demonstrated. A sensitivity analysis has also been carried out to show the influence of the various parameters. It has been found that material properties and their inter-relations significantly influence weight loss of rebar. Time to cover cracking from onset of corrosion for the same weight loss is influenced by corrosion rate and state of oxidation of corrosion product formed. Time to cover cracking from onset of corrosion is useful in making certain decisions pertaining to inspection, repair, rehabilitation, replacement and demolition of RC member/structure in corrosive environment.

• 한국환경생태학회지
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• 제37권4호
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• pp.302-314
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• 2023

본 연구에서는 생물다양성협약(CBD) 글로벌 보전목표(K-M GBF)의 핵심이라고 할 수 있는 실천목표 3(30by30)에 대한 우리나라의 효과적 대응 방향을 모색하기 위한 것으로, OECM에 대한 글로벌 개념 고찰 및 전문가 인식조사를 통해 국가 차원의 체계적인 OECM 발굴방향을 모색하고자 하였다. 글로벌 표준을 준수하되 한국적 맥락을 반영한 국가 차원의 체계적인 OECM 발굴방향을 모색을 위해 본 연구에서는 ①OECM 관련 한국적 용어 사용, ②글로벌 표준을 반영한 결정인자(criteria) 도출, ③우리나라 잠재 OECM 후보 유형 도출, ④OECM 발굴‧보고 시 고려사항 등을 검토하였다. 먼저 OECM의 단순 번역어 사용이 아닌 이의 개념을 잘 반영한 '한국적 용어' 사용에 대한 공감대 형성이 있었으며, 가장 선호되는 용어이자 '자연과 조화로운 삶'이라는 생물다양성협약(CBD) 2050 비전과도 그 맥락을 같이하는 '자연공존지역(12명)'이 타당한 것으로 나타났다. 글로벌 표준을 반영한 주요 결정인자로는, 1단계 선별과정에서 OECM 핵심 특성을 반영한 4개 결정인자(1. 보호지역 여부, 2. 지리적 경계, 3. 거버넌스‧관리, 4. 생물다양성 가치)를 활용하고, 개별지역 심층진단을 수행하기 전에 관리‧관할기관 등과의 공감대형성(2단계) 과정을 거친 후 3단계(발굴‧보고단계)에서 2가지 결정인자(3-1 거버넌스와 관리의 효과성과 지속성, 4-1의 생물다양성 가치의 장기적 보전성과)를 추가하여 심층 진단을 수행하는 방향을 제시하였다. 본 연구에서 살펴본 28개 유형은 대체적으로 OECM 부합성이 높은 것으로 나타났으며(4.45~6.21점/7점, 평균 5.24점), 특히 자연환경국민신탁의 보전재산(6.21점) 및 보전협약지(6.07점)가 OECM 개념에 가장 잘 부합할 것으로 나타났다. 이어 세계자연유산 완충구역(5.77점), 사찰림(5.73점), 개발제한구역(5.63점), 비무장지대(5.60점), 생물권보전지역 완충구역(5.50점) 등이 잠재성이 높은 것으로 나타났다. 절대보전무인도서의 경우 보호지역에 부합한다는 응답(5.83/7점)이 OECM 부합성(5.52/7점) 보다 더 높게 나타나, 향후 절대보전무인도는 그 주변해역(1km)과 더불어 한국보호지역데이터베이스(KDPA)에 등재를 추진하는 것이 바람직할 것으로 판단된다. OECM 관련 글로벌 표준 검토 및 전문가 인식조사 결과를 토대로, 한국적 맥락의 OECM 발굴시 고려사항으로 10가지를 제시하였다. 향후 이러한 고려사항을 참고하여 단계적인 발굴사업을 통해 OECM을 목록화하고 기존 보호지역과의 연계를 통한 국가 차원의 현지-내 보전체계 정립을 위한 지속적인 연구가 필요할 것으로 판단된다.