• Journal of the Korean Wood Science and Technology
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• 제43권1호
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• pp.36-42
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• 2015

This study examined true modulus of elasticity (MOE) and modulus of rigidity (G) for domestic woods with different slenderness ratios (L/D) using the static bending and stress wave tests. Bending properties of small clear wood specimen of three domestic wood species were determined at 12% moisture content. The results of this study indicated that both MOR and MOE of domestic woods were affected by the slenderness ratio. As the slenderness ratio increased, MOR and MOE increased. G and true MOE of domestic timber beams were obtained at different slenderness ratios by flexure test and stress wave test. The values reported here can be useful if these species woods are used for structural purposes. However, the reported values are only indicative and do not represent the true average of wood species due to the limited number of specimens tested.

• Fire Science and Engineering
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• 제28권2호
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• pp.20-25
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• 2014

In this study, the extinguishing performance evaluation of wetting agent for wood crib was conducted by using a scale model equipment that we designed. To confirm the optimal conditions of the experiment, a test was changed amount of fire extinguishing water and the number of timber. As a result, the discrimination of the fire extinguishing performance was seen only when 20 pieces of wood and the extinguishing water of 100 mL were used. After evaluating the extinguishing performance of domestic and foreign wetting extinguishing agents under these conditions, a reignition was occurred in only when we used water. In addition, the discrimination of extinguishing performance was seen through the temperature distribution according to the time of watering. Based on the results of this experiment, this study is expected to be able to use as a basis on presenting a method of optimized performance evaluation of wetting extinguishing agent.

• Journal of Forest and Environmental Science
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• 제13권1호
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• pp.1-27
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• 1997

This study was to survey the flora of resources vascular plants in the Experiment Forests of Kangwon National University. Resources vascular plants were composed of 98 families, 345 genera, 551 species, 2 subspecies, 88 varieties, 10 formae, and 2 hybrid, totaling 653 taxa. Among the investigated resources plants, Korean endemic plants and rare or endangered plants were distributed 20 taxa and 18 taxa, respectively. There were 27 taxa of Naturalized plants in this study area, which would have unpredictable influence on the natural ecosystem. The urbanized index(UI) of all over the investigated areas was about 12.4%. Useful resources plants were composed edible source(42.1%), medicinal source(33.8%), pasture source(28.8%), ornamental source(11.8%), timber source(5.2%), fiber source(1.4%), industrial source(1.1%). Vascular plants of unknown use were 140 taxa(21.4%).

• Journal of Korean Society of Forest Science
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• 제3권1호
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• pp.10-14
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• 1963

1. This is a study on the utilization volume of the 94 native Korean red pines in Kwangyan Forests. 2. The formulas which derived by the above investigation are follows. a. Hight growth curve ; $H=4.76+0.125D+0.0026D^2$ b. Cubic volume formula; $V=0.0000839D^{2.3}\;H^{0.2}$ c. The relation between utilization volume and log length ; Vu=0.1708-0.0230L d. The percentage of utilization, when length was 2 meters; $P=27.37\;D^{0.3648}$ e. The number of 2 meter long timbers; $N=0.0863D^{1.16}$ f. The equation of the utilization timber volume when log length was 2 meters; $Vu=0.0000159D^2\;H^{1.3}$ 3. As a conclusion, it was found that the utilization volume in the case of 2 meter log, was most greater than the others.

• Journal of Korean Society of Forest Science
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• 제11권1호
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• pp.25-32
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• 1970

Site-index curves for Pinus densiflora Sieb. et Zucc. grown in the middle part of Korea were developed from stem analysis data by a procedure of guide curve equation $Yt=K-ab^t$ (t=0, 1, 2, ${\cdots}{\cdots}$) and shown in Fig. 2. The stand density expressed as size-number criteria was calculated and the relation of number of tree per hectare and average DBH was presented in Fig. 3, in which soil fertility showed little effect. When this is compared to Reineke's density standards, the Pinus densiflora stand ranks high level of stocking density (Fig. 5). As a measure for estimating timber volume, the angle-summation technique revealed to result wider variation. Constructing hypothetical populations for appraising angle-summation technique, the significance of its application in silvicultural and ecological research are discussed.

• Coupled systems mechanics
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• 제9권2호
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• pp.147-161
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• 2020

Constructive merging of "basic" systems of different behavior creates hybrid systems. In doing so, the structural elements are grouped according to the behavior in carrying the load into a geometric order that provides sufficient load and structure functionality and optimization of the material consumption. Applicable in all materializations and logical geometric forms is a transparent system suitable for the optimization of load-bearing structures. Research by individual authors gave insight into suitable system constellations from the aspect of load capacity and the approximatemethod of estimating the participation of partialstiffnesswithin the rigidity ofthe hybrid system. The obtained terms will continue to be the basisfor our own research of the influence of variable parameters on the behavior of hybrid systemsformed of glued laminated girder and cable of different geometric shapes. Previous research has shown that by applying the strut-type hybrid systems can increase the load capacity and reduce the deformability ofthe free girder.The implemented parametric analysis pointsto the basic parameterin the behavior of these systems-the rigidity ofindividual elements and the overallstiffnessofthe system.The basic idea ofpre-stressing is that, in the load system or individual load-bearing element, prior to application of the exploitation load, artificially challenge the forcesthatshould optimize the finalsystembehaviorin the overall load. Pre-stressing is possible only if the supporting system orsystem's element possesssufficientstrength orstiffness, orreaction to the imposed forces of pre-stressing. In this paper will be presented own research of the relationship of partial stiffness of strut-type hybrid systemsofdifferentgeometric forms.Conducted parametric analysisofhybridsystemswithandwithoutpre-stressing, and on the example of the glulam-steel strut-type hybrid system under realistic conditions of change in the moisture content ofthe wooden girder,resulted in accurate expressions and diagramssuitable for application in practice.

• Journal of Forest and Environmental Science
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• 제29권2호
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• pp.147-156
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• 2013

Multiple use forestry is capable of generating income for forest based communities through Non-Timber forest products (NTFPs) which provide food, medicine, materials for domestic use and cash income for communities adjoining forest areas in developing countries. This study evaluates the economics of producing ginger rhizomes under teak canopy in a multiple land use system during 2007 and 2008 in even aged teak plantations in Ibadan and Ife, Nigeria. Twelve $6m^2$ sample plots were randomly selected in Completely Randomized Block Design within and outside the plantation. Average ginger rhizome of (50-60 g) were planted on the slightly tilled soil. NPK 15:15:15 was applied at 180 kg/ha on a split unit dose. ANOVA, Profitability, Benefit-Cost (B/C) ratio were used to analyze data. Results showed no significant differences between sites in ginger rhizome yield, (0.089 and 0.718, ${\rho}{\leq}0.05$) in 2007 and 2008 respectively. Average yield were higher outside teak canopy in both sites and treatments, (Ibadan -40.05 g>32.9 g, Ife -67.6 g>25.2 g and Ibadan -41.3 g>31.5 g, Ife -66.8 g>25.0 g) with and without NPK respectively. NPK had no effect on yields within teak plantation, (Ibadan -31.5<32.9 g, Ife -25 g<25.2 g). Ginger rhizome production was viable financially without inorganic fertilizer during second cropping season within and outside plantation (B/C=1.02, 1.09) respectively. Ginger could be raised profitably under teak canopy, however, studies on insolation requirement of ginger under teak canopy and other tree plantations are recommended.

• Journal of architectural history
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• 제16권1호
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• pp.83-99
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• 2007

This study examines the joint and splice of wooden structure at Geunjeongjeon Hall of Gyengbok Palace, which was constructed in the late Joseon Dynasty. The scope of the study is on the part of columns, the bracket sets, and the frame structure. This research also deals with the relationship between vortical load and horizontal load. Firstly, the examination of the joint and splice methods between the pillar and penetrating ties is on the joint and splice methods of the outer and corner. Through the investigation, it is verified that the joint methods between pillar and penetrating tie on the outer and corner pillars is the method of Sagal joints(cross joints, 사개맞춤). Joints used between pillar and penetrating tie are dovetailed tenon joints, between columns and Anchogong(안초공), between columns and Choikgong(초익공) are tenon joint(장부맞춤). Secondly, the examination of the joint and splice methods of the bracket set is on that of Salmi and Cheomcha(첨차), and Salmi and Janghyeo(장혀). Joints used between Salmi and Cheomcha, Salmi and Janghyeo are halved joint, and between each Janghyeo are stepped dovetailed splice. It is Cheomcha that is used the Jujang-Cheomcha(주장첨차) on center line. Therefore it is connected with each bracket set, which gets to is the strong system, easy and convenient on the construction of that. Thirdly, the frame structure of wooden architecture in royal palace is consist of purlins and beams, Janghyeo(장혀, timber under purlin), tall columns, king posts, etc. Through the investigation, it is verified that the joint and splice methods between purlins and beams are used with the methods of Sungeoteok joint(숭어턱맞춤). It is verified that the joint and splice methods between beams and high columns are used with methods of mortise and tenon joint(장부맞춤), is highly related with tensile force. To reduce the separation of parts, sangi(산지) and tishoi(띠쇠) are used as a counterproposal, which were generally used for architecture in royal Palaces in the late Joseon Dynasty and continued to be used until these days common wooden architecture.

• Journal of architectural history
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• 제19권6호
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• pp.233-250
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• 2010

Jukseoru as an official pavilion of the government, one of the eight sceneries in Gwndong Area, is located on the cliff over Osipcheon River. This paper interprets form and space of the pavilion with restored old life by analyzing pictures of official party in 18th century in Chosun Dynasty. Every part of the space is occupied by persons by the class and duty: the pricipal guest, nobles, subordinates, gisaengs, court musicians, and guards from the high to the low and from the inside to the outside. Applying the analysis to the Jukseoru pavilion, the noblest lord takes sit on the platform in front of folded screen at main bay under checked ceiling, enclosed by low timber beam. The next northern end bay is a place for subordinates' and servants' waiting for preparation for rice wine. Southern end entrance bay is not a result of later addition but deliberately and originally made for lower place outside the railing of wooden floor: for a waiting woman gisaeng, and subordinates. Outside under the eaves on the platform with bedrock, artificial stone and soil is a place for court musicians, subordinates, and guards. The yard in front of the building is a place for preparing meals by cookers. Every detailed ornamental form is different each other by the place for the occupied class. Existing theory tells that the building, 7 bays gable-and-hipped roof, is a result of structural extention of 2 bays at the 5 bays gabled-roof. However, through the interpretation of old pictures and application to the pavilion, the present Juseoru is not a result of later structural addition, but deliberately designed creation suited to life in hierarchical traditional society.

• Korean Journal of Plant Resources
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• 제15권3호
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• pp.188-210
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• 2002

Tonggo-san(1066.5m) is located at 36° 53' 00" - 36" 55' 00" in latitude, at 129° 10' 30" - 129° 13' 00" in longitude and on Seo-myeon, Uljin-gun and Subi-myeon, Yeongyang-gun in Gyeongsangbuk-do. Tonggo-san shows the typical vegetation patterns including the middle area of temperate region of Korea represented by the secondary forests of Quercus mongolica and Q. dentata. There was no detailed result on the flora and vegetation of Tonggo-san until now. Therefore, we tried to discuss on the distribution and availability of vascular plants including economical plants. Also, we could discuss the especialized plants and their distributions according to the criteria by the Ministry of Environment. The results of plant collection and their investigation from April in 2001 to November in 2001 are as follows : The vascular plants consist of total 565 taxa; 17 forms, 82 varieties, 466 species, 297 genera, 94 families,37 orders, 4 classes, 2 subphyla. In this area, there were a lot of useful economic plants such as 232 taxa(41%) of edible source, 222 taxa(39％) of forage source, 183 taxa(32%) of medicinal source, and 72 taxa(12%) of ornamental source, 15 taxa(2.6%) timber source, 7 taxa(1.2%) industrial raw material source respectively. Among them, the Korean endemic plants were 22 taxa(3.9％ among total 565 taxa); 1 forms, 2 varieties, 19 species, 22 genera, 16 families. And rare and endangered plants was 1 taxa; Astragatus membranaceus. Also, the naturalized plants were 19 taxa(3.4% among total 565 taxa and 10.4% among the total naturalized plants in Korea).