• 농업과학연구
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• 제24권1호
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• pp.6-10
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• 1997

초장, 엽수, 경수, 경직경, 엽장, 엽폭, 근경생산량을 평가하기위하여 수집 한 94 clone은 경수와 근경생산량에서 유용한 변이를 보여주었다. 초장, 엽수, 엽장, 엽폭, 경직경은 약간의 변이가 관찰되었다. 작물학적 특성간의 단순상관은 근경생산량과 정의 상관을 보여주었고 엽수, 초장, 경직경은 근경생산량과 고도의 정의 상관을 보여주었다. 경로계수분석을 통하여 경수, 엽수, 경직경순으로 근경생산에 직접효과를 준다는 결과를 얻을 수 있었다. 엽수를 통한 초장의 간접효과가 가장 크게 나타났고, 엽수를 통한 엽장, 엽폭과 경직경을 통한 초장, 엽장, 엽폭에서도 간접효과가 관찰되었다. 선발의 관점에서 볼 때, 초장, 엽수, 경수와 같은 특성들은 좋은 유전형을 선발하기에 적합하다고 여겨진다.

• Journal of the Korean Wood Science and Technology
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• 제43권2호
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• pp.145-155
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• 2015

Fiber morphology and basic characteristics of Legi bamboos (Gigantochloa atter) growing on Yogyakarta were studied considering their age and height positions in the culms. Culms of 4, 16, and 40 months were harvested, and their total lengths were measured. The length, diameter, and wall thickness of each internode were measured. All the sample culms were divided into three different parts along the height, and their fiber dimension and physical properties were observed. The data obtained were analyzed by analysis of variance. The results showed that the culms had a diameter of 5.8 to 10.8 cm. The lowest internodes always showed the shortest length and the thickest wall. The culms had an average fiber length of 2.41 mm and Runkel ratio of 0.61. Fiber length was affected by the height, while fiber diameter, lumen diameter, and fiber wall thickness were affected significantly by the age of the culms. The culms had high green moisture content (GMC) of 157.89%, and basic density (BD) of $456.67kg.m^{-3}$, a total longitudinal shrinkage of 0.35%, and relatively low R/T shrinkage ratio. The interactions between age and height were affected GMC and BD.

• Design & Manufacturing
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• 제15권4호
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• pp.24-31
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• 2021

In this study, an artificial neural network model was constructed to convert CAE analysis data into similar experimental data. In the analysis and experiment, the injection molding data for 50 conditions were acquired through the design of experiment and random selection method. The injection molding conditions and the weight, height, and diameter of the product derived from CAE results were used as the input parameters for learning of the convert model. Also the product qualities of experimental results were used as the output parameters for learning of the convert model. The accuracy of the convert model showed RMSE values of 0.06g, 0.03mm, and 0.03mm in weight, height, and diameter, respectively. As the next step, additional randomly selected conditions were created and CAE analysis was performed. Then, the additional CAE analysis data were converted to similar experimental data through the conversion model. An artificial neural network model was constructed to predict the quality of injection molded product by using converted similar experimental data and injection molding experiment data. The injection molding conditions were used as input parameters for learning of the predicted model and weight, height, and diameter of the product were used as output parameters for learning. As a result of evaluating the performance of the prediction model, the predicted weight, height, and diameter showed RMSE values of 0.11g, 0.03mm, and 0.05mm and in terms of quality criteria of the target product, all of them showed accurate results satisfying the criteria range.

• 한국안전학회지
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• 제39권1호
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• pp.1-8
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• 2024

Commercial gas stoves feed primary air to the burner and burn the fuel-air mixture in a partially premixed combustion. This mechanism produces carbon monoxide during combustion. In this study, design parameters of a commercial gas stove were optimized by considering the carbon monoxide emission. Gas consumption rate, carbon monoxide emission, and water boiling temperature as a heating performance were determined. Carbon monoxide emission was measured using a Korean Industrial Standards standard collector. Water boiling temperature was measured by first soaking the pot in water for approximately 10 min and then heating the pot filled with water. A thermocouple was installed inside the pot. Carbon monoxide increased as the nozzle diameter was increased and the burner-pot height was decreased. This result was due to the insufficient mixing between the fuel and air. Heating performance was enhanced when the nozzle diameter was increased and the burner-pot height was decreased. However, the heating performance deteriorated when the nozzle diameter was 1.8 mm and the burner-pot height was reduced to 50 mm. This phenomenon was due to the formation of a flame on the side of the pot. A merit factor was defined to find the optimal design parameters to satisfy gas consumption rate, carbon monoxide emission, and heating performance. Optimal design values were established to be a nozzle diameter of 1.5 mm and a burner-pot height of 60 mm.

• 생태와환경
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• 제49권3호
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• pp.236-243
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• 2016

본 논문은 국립공원 아고산대 침엽수림을 효과적으로 보전하고 관리하는 데 기초자료로 활용하고자 진행된 사례연구로서 지리산국립공원과 속리산국립공원의 아고산대에서 현지 조사된 구상나무 (Abies koreana Wilson) 210개체의 서식실태 자료를 바탕으로, 입지환경의 기본이 되는 지리적 위치와 지형적 특성이 구상나무의 생장에 미치는 영향을 분석하였다. 이를 위해서 구상나무의 생장과 관련된 변수는 수고 및 흉고직경으로 하고, 지형적 특성은 GIS 공간분석을 이용하여 추출된 지리적 위도, 해발고도, 산지경사, 사면향 그리고 지형습윤지수로 하였다. 두 변수군의 연관성의 유무와 정도를 평가하기 위해서 정준상관분석을 이용하고, 다중회귀분석을 이용하여 지리 지형적 특성이 구상나무의 생장구조에 미치는 영향을 평가하였다. 구상나무 생장구조를 나타내는 흉고직경 및 수고는 지형의 수직적인 분포보다 지리 위도적인 분포와 연관성이 더 크고, 지리 지형요소는 수고보다 흉고직경과 연관성이 더 큰 것으로 나타났다. 구상나무의 생장구조변수와 지리 지형변수는 유의한 상관관계가 있고, 지리 지형변수가 생장구조변수를 18.1% 정도 설명하는 것으로 나타났다. 구상나무의 흉고직경에 영향을 주는 변수는 지리적 위도, 지형습윤지수, 사면향 그리고 해발고도의 순으로 통계적 유의성이 있는 것으로 나타났다. 위도가 높아질수록 흉고직경은 작아지고 지형적 요소에 따라서는 커지는 것으로 나타났다. 수고에 영향을 주는 변수는 지형습윤지수만이 유의미한 것으로 나타났다. 전반적으로, 구상나무의 생장구조와 관련된 수고와 흉고직경은 지리적인 특성의 영향이 가장 클 것으로 나타났다. 특히 지형적 특성 중에서 수분상태의 영향이 다른 지형요소에 비해서 더 클 것으로 예측되었다. 이러한 결과로 볼 때, 지리 지형적인 특성은 구상나무의 생장에 중요한 요인이 될 것으로 추측된다. 비록 지리 지형적 특성만을 고려하고 GIS를 이용하여 제작된 공간분석 자료를 사용한 한계가 있다고 해도, 본 연구결과는 향후 국립공원 아고산대에서 서식하고 있는 침엽수림의 생장환경을 조사하고 연구하는 데 유용하고, 구상나무 등 상록침엽교목을 효과적으로 관리하고 보전하기 위해서 대책을 수립하는 데 기초자료로 활용될 것으로 기대된다.

• Geomechanics and Engineering
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• 제4권4호
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• pp.251-262
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• 2012

Triaxial tests are essential to estimate the shear strength properties of the soil or rock. Normally triaxial tests are carried out on samples of 38 mm diameter and 76 mm height. Granular materials, predominantly used in base/sub-base construction of pavements or in railways have size range of 60-75 mm. Determination of shear strength parameters of those materials can be made possible only through triaxial tests on large diameter samples. This paper describes a large diameter cyclic triaxial testing facility set up in the Geotechnical Engineering lab of Indian Institute of Science. This setup consists of 100 kN capacity dynamic loading frame, which facilitates testing of samples of up to 300 mm diameter and 600 mm height. The loading ram can be actuated up to a maximum frequency of 10 Hz, with maximum amplitude of 100 mm. The setup is capable of carrying out static as well as dynamic triaxial tests under isotropic, anisotropic conditions with a maximum confining pressure of 1 MPa. Working with this setup is a difficult task because of the size of the sample. In this paper, a detailed discussion on the various problems encountered during the initial testing using the equipment, the ideas and solutions adopted to solve them are presented. Pilot experiments on granular sub-base material of 53 mm down size are also presented.

• Journal of Plant Biology
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• 제9권1_2호
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• pp.7-16
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• 1966

In order to determine the factors related to site quality, 13 areas of Larch growing in the Kwangung and its vicinity forest as sample plots, were examined. Sample plots included various site classes as well as age classes. Three were divided into two groups (major and minor trees). Average height of dominant trees was determined through messurement of 5 to 6 dominant tree in each sample plots. Average height of dominant 30 year-old trees was the basis for site index. A Standard Yield Table for the larch produced in Kwangnung forest was made by various data, which included age class 5, ranging from 10 to 45 years. The relationship of the height of the trees, the site conditions, and ground vegetation are investigated in this paper. The site indexes of 40 forest class age in 28-B and 28-G forest classes of the larch associations for ground vegetation had comparatively rarge differences due to the sampled areas. The relation of the direction of forest communities to the height and the diameter of the tree shwoed that its communiteis of northest and northwest parts appeared higher valueof the height and the diameter. The diameter and the height of trees were closely realted to each other. The samller the occupied area per tree and the smaller the average distance among trees, the more density was increased. The larger the density was the lower height of the trees. In the ground vegetation of the larch communities, there seems to be a definite correlation between the height of trees and the occupied area per tree or the average distance among the trees. The height of trees and site index of two larch communities were as follow: 28-B forest class site index 20.8, height 24.0m, 28-G forest class site index 18.4, height 20.9m. The ground layer was analyzed by the method of Quadrat(20/20sq. cm) with an interval of 1M. It set up 40 Quadrats of the larch communiteis. The community structure of the ground vegetation of two larch was analyzed, and important value was calculated and then evaluated. The ground vegetation under the larch had developed Burmannii Beauv stratal society below the 28-B and 28-G the forest class. Accordingly, the first important value of Burmannii Beauv was found in two ground vegetation below the larch. Therefore, this species could be quantitatively considered as the forest indicator species. Common species of each community appeared 18 species out of 34 species in the ground vegetation under two larch communities. The ground vegetation of the 28-B forest class showed more than that of the 28-G forest class. the similarity of the ground vegetation was measrued by the Frequency Index Community Coefficient. The differences between the associations were lcearly manifested by the ground vegetation tested by Gleason's Frequency Index of Community Coefficient for the analysis of each stratal society of all associations. According to F.I.C.C. the ground vegetation under two larch(28-B and 28-G) forest classes showed higher value. An investigation into the relationship of physical and chemical properties of soil and site was considered the next step to be taken in the study of the larch site classification.

• International Journal of Concrete Structures and Materials
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• 제5권1호
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• pp.49-55
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• 2011

The main objective of this investigation is to study size effect on compressive strength of CFRP confined concrete cylinders subjected to axial compressive loading. In total 24 concrete cylinders with different sizes were tested, small specimens with a diameter of 100 mm and a height of 200 mm, medium specimens with a diameter of 200 mm and a height of 400 mm, and big specimens with a diameter of 300 mm and a height of 600 mm. The lateral confining pressure of each specimen is the same and from that hypothesis the small specimens were confined with one layer of CFRP, medium and big specimens were performed by two and three layers of CFRP respectively. Test results indicate a significant enhancement in compressive strength for all confined specimens, and moreover, the compressive strengths of small and medium specimens are almost the same while a bit lower for big specimens. These results permit to conclude that there is no size effect on compressive strength of confined specimens regardless of cylinder dimension.

• Asian-Australasian Journal of Animal Sciences
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• 제30권12호
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• pp.1718-1723
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• 2017

Objective: The study explored the dynamics of shearing force and its correlation with chemical compositions and in vitro dry matter digestibility (IVDMD) of stylo. Methods: The shearing force, diameter, linear density, chemical composition, and IVDMD of different height stylo stem were investigated. Linear regression analysis was done to determine the relationships between the shearing force and cut height, diameter, chemical composition, or IVDMD. Results: The results showed that shearing force of stylo stem increased with plant height increasing and the crude protein (CP) content and IVDMD decreased but fiber content increased over time, resulting in decreased forage value. In addition, tall stem had greater shearing force than short stem. Moreover, shearing force is positively correlated with stem diameter, linear density and fiber fraction, but negatively correlated with CP content and IVDMD. Conclusion: Overall, shearing force is an indicator more direct, easier and faster to measure than chemical composition and digestibility for evaluation of forage nutritive value related to animal performance. Therefore, it can be used to evaluate the nutritive value of stylo.

• 한국산림과학회지
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• 제96권2호
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• pp.138-144
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• 2007

This study was undertaken to compare the biomass of Abies koreana growing at two sites. A $10{\times}10m$ plot was established in each site of a natural stand in Mt. Jiri and a plantation in Gyeongsan nursery. Five trees of A. koreana were randomly selected in each site. The following traits were investigated from each tree : height, basal diameter, age, weight of stem, branches, and needles as above-ground traits and weight of total roots, horizontal roots, and vertical roots as below-ground traits. In Gyeongsan nursery, age of sample trees was negatively correlated with both height and weight of total stem, while height was highly correlated with weight of horizontal roots. There was high correlation between the basal diameter and weight of total stem, and between the basal diameter and weight of roots. In Mt. Jiri stand, most of the above-ground traits except age were significantly correlated with the below-ground traits. The linear regression equation between the cross section area of base (X) and the weight of total stem (Y) in Gyeongsan nursery was Y=12.66X-12.92, and correlation was significant ($R^2=0.89$). The linear regression equation between the cross section area of base(X) and the weight of total branches (Y) in Mt. Jiri stand was Y=25.51X+6.00, and correlation was highly significant ($R^2=1.0$).