• Journal of Plant Biology
• /
• 제9권1_2호
• /
• pp.25-30
• /
• 1966

The writer presented in the report 7th of this series(Chong, 1959. '62 a.b. '64, '65) the result of fertlizer application on Sasamorpha purpurascens var. borealis with regards to soil conditions, climate, planting position etc. and this report is on the effectiveness of fertilizers by kinds of the new (1-year old) and old(3-to 4 years old) Phyllostachys retticulata. The ineffectiveness of fertilizers for old bamboos aged more than 8-years old has been reported previously. The study site was chosen in a bamboo groven situated at Hyunnae Ri, Okkye Myun, Myungju Gun, Kangwon Do. Each plot was so designed that only one individual remained at the center of a circular area with a dimeter of meters by eliminating the clums and severing the rhizomes, of other individuals around it. And, for the fertilizer test, 10 individuals(the new and old: 5 to 5) were observed per kind of fertilizer used; thus marking the total number of 160 plots in all. The second part of this study was conducted for the potted individuals which numbered 48, successfully established ones out of 55 the transplanted to pots. The 48 were divided into 8 treatments: whole fertilization (NPK＋compost＋human manure); NPK; N; K; Human manure; compost; and the control. Amoung of fertilizers applied was 200 grams for the natural plots and 100 grams for pot; it continued for 3 years and applied twice a year (spring and summer) following the theory of Dr. Koichi-ro Ueda(1954, '60 a.b.). Measurements were taken in August each year. The resutls were confirming the fact that the bamboos require a great deal of fertilizers. The results show the following points: 1) Fertilizers were more effective in the 3 to 4 year old bamboos. 2) The order of effectiveness of fertilizers by kind was the whole fertilization, NPK, and N treatments for Phyllostachys reticulata. 3) Organic matter in addition to commercial fertilizers showed better result than the soil application of the latter due to better soil aeration.

• Journal of Forest and Environmental Science
• /
• 제38권2호
• /
• pp.90-101
• /
• 2022

The study aims to assess composition, diversity and population indices of natural regeneration of woody species in Jebel El Gerrie forest reserve, Blue Nile State, Sudan. We conducted field work between December 2018 and January 2019. We used random sampling to collect vegetation data in the forest where we made a total of 90 circular sample plots (radius 17.84 m) and distributed them proportionally to the area of each of the four density-based vegetation classes of the forest i.e. high density (C1), medium density (C2), low density (C3) and crop land (C4). In each sample plot we identified all regenerating tree species and counted their regeneration frequencies. We calculated ecological metrics of regeneration frequency, density, abundance, richness, evenness, diversity and importance value index (IVI) and drew abundance rank curve. Results revealed that out of fifteen mature tree species present, natural regeneration of 8 species, which belong to 6 families, was observed. The relatively most frequently naturally regenerating and abundant species were Anogeissus leiocarpa and Combretum hartmannianum. Richness, evenness and diversity of regenerating species were 1.33, 0.82 and 1.7, respectively. One-way ANOVA (α=0.05) of mean regeneration densities disclosed that there were significant differences (F_3,86=16.77, p=0.000) between C2 & C3 (p=0.000) and C2 & C4 (p=0.000). While regeneration of seven tree species were absent, two, two and four species were of good, poor and fair regeneration status, respectively. A comparison of mean density of natural regeneration with that of parent trees reflects a poor regeneration status of the forest. The study provides empirical results on the regeneration status of species and signifies the need for management interventions for species conservation and restoration, maintenance of biodiversity and sustainable production.

• Journal of Forest and Environmental Science
• /
• 제38권3호
• /
• pp.174-183
• /
• 2022

The study aims to examine population indices of mature trees in Jebel Elgarrie forest, Blue Nile State, Sudan. We used remote sensing techniques to stratify the forest into vegetation classes depending on tree density. We distributed 97 circular sample plots (0.1 ha) proportionally to the area of the vegetation classes. In each sample plot we identified, counted and recorded all mature trees (DBH ≥10 cm). We calculated frequency, density, abundance, richness, evenness and diversity for each species and we drew abundance rank curve of mature trees. We used One-Way ANOVA to test for differences (α=0.05) in mean density (No./ha) of mature trees between vegetation classes. Results revealed that the forest was conveniently sub-divided into high density (C1), medium density (C2), low density (C3) and bare farm land (C4) classes. We identified fifteen tree species that belong to 10 families and 14 genera. Combretaceae and Fabaceae were the common families while Anogeissus leiocarpa was the most frequently occurring species. While species diversity varied between vegetation classes, diversity of the forest as a whole is low. While mean density of mature trees in C1, C2, C3 and C4 it was 100, 74, 10, and 0, respectively, it was 54 for the whole forest indicating low stocking, Following One-Way ANOVA, multiple comparisons revealed significant differences in mean density of mature trees between C1 & C3 and C2 & C3. The study provided empirical results on population indices of mature tree species, which would be of importance for successful management and conservation of the forest.

• 한국산업융합학회 논문집
• /
• 제25권6_2호
• /
• pp.1111-1117
• /
• 2022

Recently, interest in the circular economy has emerged in the industry. As a result, interest in Re-manufacturing, which makes old equipment similar to new products, is growing. In the machine tool industry with many aging equipment, the Re-manufacturing industry is essential, and among them, research on the performance improvement of gear type oil pumps was conducted. The purpose was to achieve the target performance of flow rate and volume efficiency by changing the shape of the gear pump housing clearance and inlet/outlet, and Computational Fluid Analysis and Central Composite Design were conducted using ANSYS CFX 2022 R2 and MINITAB®. The level of each determined factor was determined. 20 design points were derived, and the Flow Rate at each design point was calculated, and the Theoretical Flow Rate was calculated to obtain Volumetric Efficiency. The optimal design point was obtained when the Flow Rate was 140 lpm and the Volumetric Efficiency was maximum, the optimal design point was obtained when both were maximum, and the Surface Plot for each factor was obtained to identify the tendency.

• Journal of Forest and Environmental Science
• /
• 제26권3호
• /
• pp.149-159
• /
• 2010

This paper analyzes data on the composition, status, diversity, and distribution pattern of invasive forest undergrowth in a protected area (Khadimnagar National Park) of Northeastern Bangladesh. Assessment was done by means of stratified random sampling to diversify the invasive forest undergrowth species. For vegetation survey, 45 plots were taken randomly in ($2m{\times}2m$) circular plot from three topographical regions namely top of the hill, middle slope and plain land (15 plots from each region) and a total of 715 individuals, 22 invasive species belonging to 17 families were recorded from the study site. Among invasive species, shrubs constitute 10 species, herbs 9 species, and vines 3 species respectively. Mass number of invasive undergrowth species was grows in plain land (45.45%) followed by middle slope (31.82%). Based on the survey, invasive undergrowth plants of study areas were also categorized into three degrees of invasiveness e.g., highly invasive, moderately invasive and potentially invasive. Herbs, shrubs, and vines constitute the highest density at Chromolaema odorata (Linn.) King. (1.09), relative density at Chromolaema odorata (Linn.) King. 6.85%; highest and lowest frequency was calculated at Cassia alata L. (64.44%) and Diplazium esculentum (24.44%); for relative frequency the highest was Cassia alata L., which occupies 6.64%. Determination of the abundance of the different species revealed that Cassia alata L., constitutes (3.36) followed by Pteris cretica Wilsonii (3.14) of the area. The presence of invasive undergrowth species always reduced the number of associated species. Therefore, an extensive in-depth long-term investigation, proper policy formulation and management interventions and further study and continuous monitoring on their impacts need to be triggered targeting the control of the invasive undergrowth species of this protected area. In this aspect, national and international organization could help to conserve its biodiversity.

• Structural Engineering and Mechanics
• /
• 제87권3호
• /
• pp.221-229
• /
• 2023

Urbanization and industrialization have significantly increased the amount of solid waste produced in recent decades, posing considerable disposal problems and environmental burdens. The practice of waste utilization in concrete has gained popularity among construction practitioners and researchers for the efficient use of resources and the transition to the circular economy in construction. This study employed Lytag aggregate, an environmentally friendly pulverized fuel ash-based lightweight aggregate, as a substitute for natural coarse aggregate. At the same time, fly ash, an industrial by-product, was used as a partial substitute for cement. Concrete mix M20 was experimented with using fly ash and Lytag lightweight aggregate. The percentages of fly ash that make up the replacements were 5%, 10%, 15%, 20%, and 25%. The Compressive Strength (CS), Split Tensile Strength (STS), and deflection were discovered at these percentages after 56 days of testing. The concrete cube, cylinder, and beam specimens were examined in the explorations, as mentioned earlier. The results indicate that a 10% substitution of cement with fly ash and a replacement of coarse aggregate with Lytag lightweight aggregate produced concrete that performed well in terms of mechanical properties and deflection. The cementitious composites have varying characteristics as the environment changes. Therefore, understanding their mechanical properties are crucial for safety reasons. CS, STS, and deflection are the essential property of concrete. Machine learning (ML) approaches have been necessary to predict the CS of concrete. The Artificial Fish Swarm Optimization (AFSO), Particle Swarm Optimization (PSO), and Harmony Search (HS) algorithms were investigated for the prediction of outcomes. This work deftly explains the tremendous AFSO technique, which achieves the precise ideal values of the weights in the model to crown the mathematical modeling technique. This has been proved by the minimum, maximum, and sample median, and the first and third quartiles were used as the basis for a boxplot through the standardized method of showing the dataset. It graphically displays the quantitative value distribution of a field. The correlation matrix and confidence interval were represented graphically using the corrupt method.

• 한국산림과학회지
• /
• 제17권1호
• /
• pp.35-42
• /
• 1973

천연활엽수림(天然闊葉樹林)은 수형(樹型)이 불규칙(不規則)하며 이용가치(利用價値)도 떨어진다. 우리나라에서의 활엽수림(闊葉樹林)은 대체(大體)로 오지(奧地)에 위치(位置)하고 있으며 개발(開發)에 문제점(問題點)이 허다(許多)하겠으나 총축적량(總蓄積量)이 부족(不足)한 현금(現今) 이의 개발이용(開發利用)의 필요성(必要性)이 대두(擡頭)되고 있다. 이러한 시점(時點)에서 본(本) 연구(硏究)는 천연활엽수(天然闊葉樹) 조사(調査)에 알맞은 추출법(抽出法)을 구명(究明)하므로서 조사사업(調査事業)에 이바지할 수 있다고 하겠다. 본(本) 조사(調査)는 1. 10ha되게 3개소(個所)를 선정(選定)하고 이를 대상(對象)으로 4가지 추출법(抽出法)을 적용(適用)하여 0.1ha($20m{\times}50m$) 구형표본점(矩形標本點) 6개(個) 즉(卽) 6%의 추출율(抽出率)로 표본(標本)을 추출(抽出) 조사(調査)하였는데 조사결과(調査結果)는 표(表) 1과 같으며 적용(適用)된 추출법(抽出法)은 (1) 격자법(格子法)에 의(依)한 임의추출법(任意抽出法) (2) 좌표법(座標法)에 의(依)한 임의추출법(任意抽出法) (3) 선표본점법(線標本點法) (4) 부차추출법(副次抽出法)이다. 2. 1:15, 000 항공사진(航空寫眞)을 이용(利用)하여 위 지역(地域)을 포함(包含)하는 지역(地域)에서 150ha 되게 구획(區劃)한 후(後) Mirror Stereoscope로 임상(林相)을 구분(區分)하였다. 경급(經級)과 소밀도(疎密度)를 기준(基準)으로 구분(區分)하였더니 3계급(階級)으로 나눠졌는데 150ha에서 계통적(系統的)으로 7개(個)(추출율(抽出率) 0.46%)의 표본점(標本點)을 배치(配置)하고 현지(現地)에서 0.1ha 원형표본점(圓形標本點)을 조사(調査)하였는데 그 결과(結果)는 표(表) 4와 같다. 3. 추출법(抽出法)에 따른 값과 매목조사결과(每木調査結果)(모평균(母平均))와를 비교(比較)하였더니 유의차(有意差)가 없었다(표(表3)). 4. 이상(以上)의 결과(結果)로 다음과 같은 결론(結論)을 얻었다. 1) 격자법(格子法)과 선표본점법(線標本點法)에 의(依)한 조사(調査)가 타추출법(他抽出法)에 비(比)하여 양호(良好)하다. 2) 원형표본점(圓形標本點)을 사용(使用)했을때는 구형표본점(矩形標本點)을 사용(使用)했을때 보다 과대치(過大値)를 가져온다. 3) 천연활엽수림(天然闊葉樹林)은 임목(林木)이 고르게 서있지 않으므로 표본점(標本點)의 수(數)를 적게 취(取)하면 오차가 커질 위험(危險)이 있다.

• 한국지리정보학회지
• /
• 제20권3호
• /
• pp.181-194
• /
• 2017

본 연구의 목적은 산림재적 현장자료와 항공 LiDAR 자료 기반의 산림재적 추정을 위한 회귀모델의 개발이다. 추정 모델은 경상북도 봉화군 지역에서 임의추출법에 의해 선정된 30개의 원형 표본지로부터 산출한 표본지별 산림재적을 반응변수로 하고, 항공 LiDAR 원자료로부터 개별 표본지의 고도분포 백분위수(Height Percentiles, HP) 및 층위 단위 점 개체수 백분율(Height Bin, HB)을 추출하여 예측변수로 사용하여 구성하였다. 단순선형회귀분석, 이차 다항회귀분석 및 단계적 회귀분석 방법을 이용한 다중회귀분석을 실시하여 적합모델들의 후보들을 도출하였으며, 검증을 위하여 각 모델별로 교차 타당성 검증을 실시하여 PRESS 통계치를 구하였다. 모델의 $R^2$ 및 PRESS을 비교하여 적합성을 검토한 결과, $HB_{5-10}$, $HB_{15-20}$, $HB_{20-25}$, $HBgt_{25}$의 다중회귀모델의 $R^2$이 0.509로 가장 높고, $HP_{25}$ 단순회귀모델의 PRESS 값이 122.352으로 가장 낮은 것으로 나타났다. 수직구조가 복잡한 우리나라 산림재적을 추정하는 모델로는 다양한 수직적 정보를 포함하고 있는 $HB_{5-10}$, $HB_{15-20}$, $HB_{20-25}$, $HBgt_{25}$이 상대적으로 보다 적합하다고 사료된다.

• 아시안잔디학회지
• /
• 제18권2호
• /
• pp.97-104
• /
• 2004

Putting green의 높은 이산화탄소 함량은 많은 골프장 관리자들에게 있어서 green 관리시 항상 난제로 여겨져 왔다. 무기성 토양은 green 근권(根圈:토양 중에서 뿌리의 영향이 미치는 범위)에서 이용 가능한 자유산소를 제한하며 그로 인하여 뿌리발달을 방해하며 잔디성장을 위한 영양분이 용도를 제지시킨다. 이 실험은 현 운영되는 골프장 (South illinois, Carbondale, U,S,A) 에서 선택 되어진 아홉 개의 green 에서 근권의 $CO_2$ 함유량과 잔디품질 (Turf qualify Index) 사이의 관계성을 조사하기 위하여 실행되어졌다. 아홉개의 putting green에서 각 green 의 다섯 곳의 소구획을 무작위로 선택하여 1998년 8월 부터 1999년 8월 까지 일곱번의 반복으로 잔디품질, $CO_2$ 함유량, 수분함량과 수분 침투율 (Infiltration rate) 을 측정하였다. $CO_2$ 함유량은 이른 봄 보다 늦은 여름에 높았으며 $CO_2$ 함유량이 높아짐에 따라 잔디품질은 급격히 낮아졌다. 수분함량이 많을수록 $CO_2$ 함유량이 높았으며 반대로 수분 침투율은 낮아짐을 보였다. 높은 수분 침투율은 $CO_2$ 함유량을 감소시켰다. 결론적으로 알맞은 토양의 물리적 조건(수분 함량과 침투율)이 $CO_2$ 함유량과 잔디성장에 있어서 매우 중요한 역할을 함을 알 수 있다. 잔디품질의 향상을 위해 putting green root zone의 알맞은 배수와 함께 근권의 공기 조건이 매우 중요함이 이 실험을 통해 조사되었다.

• Radiation Oncology Journal
• /
• 제9권1호
• /
• pp.27-35
• /
• 1991

8MHz 라디오파를 이용한 자입식 온열치료를 위한 기초실험의 일환으로 조직등가물을 이용하여 다양한 needle electrode의 배열을 통한 적정 온도분포를 규명하고자 하였고, 직접 개의 뇌실질에 자입 온열요법을 시도하여 이에 따른 조직 병리학적 소견을 관찰하고자 하였다. 조직등가물 실침에서 저자들은 needle electrode 1 cm 간격의 정방형 배치에서 횡단면상 $90\%$ relative SAR 분포가 약 1.25 cm 반경의 균일한 원형으로 관찰됨을 알 수 있었고 종단면상 needle electrode의 길이에 따라 균일한 온도분포가 이루어짐을 관찰할 수 있었다. 정상 개의 뇌실질에 자입하여 직접 정방형의 중심을 $43^{\circ}C$로 유지하며 50분간 온열요법을 시행한 후 관찰한 조직 병리학적 소견은 liquefactive necrosis, pyknosis of neuronal element 및 Polymorphonuclear leukocytes들이 회백질에서 급성기에 관찰 되었고 liquefactive necrosis 주위에 lipid-laden macrophage들이 관찰됨이 공통적인 특징 이었으며 후기 변화로 괴사조직 주위로 신경교세포의 증식이 관찰되었다.