• Journal of Forest and Environmental Science
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• 제39권2호
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• pp.96-104
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• 2023

The successful restoration program requires a comprehensive understanding of variables influencing seedling efficiency. Below-ground is hypothesized to have a major impact on seedling performance of species when planted in agriculture, and degraded areas with different types of mulching. This study investigated on Sg. Terla Forest Reserve in Cameron Highlands Pahang, Malaysia. In this study randomized complete block design (RCBD) was used. The excavation method was applied to study the root system development, above, and below ground biomass distributions under different types of mulching: coconut mulching (CM), oil palm mulching (OM), plastic mulching (PM) and control (CK). The root diameter, main root length, lateral root length, root coiling, and root direction toward to sun were recorded. The results in this study indicate that mulching had significant effect on root diameter, main root length, and root distributions among treatments while for lateral root length, root: shoot ratio, dry biomass distributions, and above and below ground biomass did not showed significant effect among treatments. The highest values for root diameter, lateral root length, main root length, root distributions, dry biomass distributions and above and below ground biomass were showed in CM treatments. However 75% of root coiling was observed in seedlings between treatments.

• 한국정보통신학회논문지
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• 제2권1호
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• pp.141-146
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• 1998

Recently, the computer vision such as part measurement, and product inspection is very popular to achieve the factory automation since the labor cost is dramatically increasing. In this paper, the diameter and the length of rope are measured by CCD camera which is orthogonally mounted on the ceiling. Two parameters which are the diameter and the length of rope are used to measure the weight of rope. If the weight of rope is reached to predetermined weight, the information is transmitted to PLC(programmable logic control) to cut the rope on the wheel. The cutting machine cuts the rope according to the information obtained from the CCD camera. To measure the diameter and length of rope on real time, the searching space for image segmentation is restricted the predetermined area according to the camera calibration position. Finally, to estimate the weight of rope, the knowledge base system which depends on the diameter, the length of rope, and weight relation between these information are constructed according to diameters of rope. This method contributes to achieve the factory automation, and reduce the production cost since the operators are unnecessary to measure the weight of rope by try-and-error method.

• Asian-Australasian Journal of Animal Sciences
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• 제19권1호
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• pp.13-18
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• 2006

Two different animal models, which differ in whether or not taking maternal genetic effect into account, for estimating genetic parameters of cashmere weight, live body weight, cashmere thickness, staple length, fiber diameter, and fiber length in Inner Mongolia White Cashmere Goat were compared via likelihood ratio test. The results indicate that maternal genetic effect has significant influence on live body weight and cashmere thickness, but no significant influence on the other traits. Using models suitable for each trait, both genetic parameters and trends were analyzed with the MTDFREML program. Heritability estimates from single trait models for cashmere weight, live body weight, cashmere thickness, staple length, fiber diameter and fiber length were found to be 0.30, 0.07, 0.21, 0.29, 0.28 and 0.21, respectively. Genetic correlation estimates from two-trait models between live body weight and all other traits (-0.06~0.07) was negligible, as were those between fiber diameter and all other traits (-0.01~0.03) except cashmere thickness (0.19). Cashmere weight and staple length had moderate to low genetic correlations with other traits (-0.24~0.39 and -0.24~0.34, respectively) except for live body weight and fiber diameter. Cashmere thickness had a strong genetic correlation with fiber length (0.81), and low genetic correlation with other traits (0.19~0.34) except live body weight. Genetic trend analysis suggests that selection for cashmere weight was very effective, which has led to the slow genetic progress of cashmere thickness and fiber length due to their genetic correlations with cashmere weight. The selection for live body weight was not effective, which was consistent with its low inheritability.

• 한국작물학회지
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• 제25권3호
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• pp.63-67
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• 1980

인삼의 재래종에 대해서 유용형질과 관계가 있는 가시 Marker gene을 탐색하고, 선발을 용역하게 할수 있는 육종의 기초자료를 얻고저 년생별 각종 농경형질간의 상관관계를 조사하였던 바 그 결과를 요약하면 다음과 같다. 1. 형질상호간의 상관관계는 년생에 따라 다소 차이가 있었으나 경직경, 엽중, 경중은 각년생 공히 거의 모든 형질과 고도의 유의성이 있는 정(+) 상관을 보였다. 2. 각년생차에 관계없이 수량형질인 근중과 상관이 높았던 지상부형질은 경직경, 엽중, 엽폭, 장엽수, 소엽수, 엽중, 경중이었으며, 이들은 모두 정(+)상관을 보였다. 3. 따라서 경직경이 굵고, 엽면적이 넓고, 엽수가 많은 것이 다수성일 것으로 사료됨으로 경직경과 엽면적 및 엽수를 표식형질로 활용, 선발하는 것이 효과적일 것으로 생각된다.

• 한국포장학회지
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• 제19권2호
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• pp.61-65
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• 2013

Modified atmosphere (MA) of reduced $O_2$ and elevated $CO_2$ concentrations has been used for keeping the quality of fresh produce and extending the shelf life. As a way to attain the beneficial MA package around the produce, a gas diffusion tube or perforation can be attached onto the container and controlled on real time in its opening/closing responding to $O_2$ and $CO_2$ concentrations measured by gas sensors. The timely-controlled opening of the gas diffusion tube can work in harmony with the produce respiration and help to create the desired MA. By use of the mathematical modeling, the effect of tube dimension on the controlled container atmosphere was figured out in this study. Spinach and king oyster mushroom were used as typical commodities for designing the model container system (0.35 and 0.9 kg in 13 L, respectively) because of their respiration characteristics and the optimal MA condition ($O_2$ 7~10%/$CO_2$ 5~10% for spinach; $O_2$ 2~5%/$CO_2$ 10~15% for mushroom). With a control logic for the gas composition to stay as close as possible to optimum MA window without invading injurious low $O_2$ and/or high $CO_2$ concentrations, the atmosphere of the sensor-controlled container could stay at its lower $O_2$ boundary or upper $CO_2$ limit under certain tube dimensional conditions. There were found to be the ranges of the tube diameter and length allowing the beneficial MA. The desired range of the tube dimension for spinach consisted of combinations of larger diameter and shorter length in the window of 0.3~2 cm diameter and 0.2~10 cm length. Similarly, that for king oyster mushroom was combinations of larger diameter and shorter length in the window of 0.9~2 cm diameter and 0.2~3 cm in length. Clear picture on generally affordable tube dimension range may be formulated by further study on a wide variety of commodity and pack conditions.

• Nuclear Engineering and Technology
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• 제53권10호
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• pp.3229-3235
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• 2021

The key process used in nuclear industries for the management of radiotoxicity associated with spent fuel in a closed fuel cycle is solvent extraction. An understanding of hydrodynamics and mass transfer is of primary importance for the design of mass transfer equipment used in solvent extraction processes. Understanding the interfacial phenomenon and the associated hydrodynamics of the liquid drops is essential for model-based design of mass transfer devices. In this work, the phenomenon of drop formation at the tip of a nozzle submerged in quiescent immiscible liquid phase is revisited. Previously reported force balance based models and empirical correlations are analyzed. Experiments are carried out to capture the process of drop formation using high-speed imaging technique. The images are digitally processed to measure the average drop diameter. A correlation based on the force balance model is proposed to estimate drop diameter and jet length. The average drop diameter obtained from the proposed model is in good agreement with experimental data with an average error of 6.3%. The developed model is applicable in both the necking as well as jetting regime and is validated for liquid-liquid systems having low, moderate and high interfacial tension.

• 한국산림과학회지
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• 제90권4호
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• pp.445-449
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• 2001

가로수용 무궁화를 만들기 위한 무궁화 수행유도 실험에서 무궁화의 지하고를 100cm, 150cm, 200cm로 하고 시비를 달리한 결과, 각각의 근원경 평균이 15.7mm, 13.8mm, 10.8mm로 지하고가 낮을수록 근원경의 생장이 우수하였으며, 분산분석의 결과도 지하고에 따른 영향이 유의한 것으로 나타났다. 그리고 시비에 따른 영향은 유의하지 않았다. 또한 가로수로 식재하여 '99년부터 2000년까지 2년 동안 조사한 결과는 지하고 80~120cm, 121~150cm, 151-200cm에서 각각의 근원경 평균이 4.9mm, 4.5mm, 3.0mm의 값을 나타내 지하고 80~120cm, 121~150cm의 근원경 생장이 좋은 것으로 나타났다. 앞으로 가로수용으로 무궁화를 육성하가 위해서는 먼저 수고와 지하고를 고려하는 것이 타당한 것으로 본 실험의 결과에서 나타났다. 그러나 본 실험의 결과는 짧은 기간의 시험에 의한 것이므로 앞으로 계속하여 관찰 연구하여 보완하고자 한다.

• 대한기계학회논문집B
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• 제21권8호
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• pp.1009-1023
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• 1997

The breakup length of a liquid jet with flowrate, formed by releasing through a nozzle of circular cross-section into the atmosphere, was experimented and studied for 3 liquid nozzles of varying diameters. The experimental result was analyzed using the existing theoretical equation for predicting the breakup length. It was found that the breakup length of liquid jet depends on the velocity, and the breakup length increases with increasing of the liquid nozzle diameter. Also, the variation range of the breakup length for the same flowrate of liquid increased rapidly as velocity was increased for laminar flow, but in the turbulent flow region, it leveled off in the range of approximately 0.55-0.7 of the mean breakup length. Furthermore, when the longest smooth liquid jet was applied to the co-axial flow air blast atomizer, the effect of air flow on the flow pattern and breakup length was studied for 6 glass nozzles of different lengths and diameters. It was found that depending on the diameter of the mixing tube and liquid jet, it was possible to observe a wide range of flow patterns, such as liquid jet through flow, partial annular flow and annular flow. The liquid jet breakup length was more sensitive to the change in the length rather than the diameter of the mixing tube. As the length of the mixing tube shortens, the breakup length also shortens rapidly.

• 터널과지하공간
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• 제15권2호
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• pp.137-144
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• 2005

이 연구에서는 최소자승법을 이용하여 절리의 직경분포를 추정하는 방법을 개발하였다. 이전에 Song and Lee가 제안한 방법에서는 현장에서 조사한 양끝내포선(contained trace) 분포로부터 무한 조사창에서 정의되는 절리선(joint trace) 길이 분포를 먼저 구하고 이 후에 직경분포를 구하게 된다. 그러나 새로 제안한 방법을 사용하면 중간 추정과정없이 현장에서 얻은 양끝내포선 분포로부터 바로 절리의 직경분포를 구할 수 있다. 이전의 방법과 비교할 때 새로 제안된 방법은 표본의 크기가 작을 때 조금 더 높은 추정정밀도를 보이며, 직경분포를 추정하는 과정에서 절리의 기하학적 파라미터의 하나인 체적빈도(volumetric frequency)도 제공한다. 새로운 추정법의 검증을 위해 Monte Carlo 시뮬레이션을 적용하였다.

• 한국강구조학회 논문집
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• 제12권3호통권46호
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• pp.259-268
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• 2000

마찰접합에 있어서 작용외력은 고력볼트로 체결된 접합부재간의 마찰면에 작용하는 마찰력에 의해 전달된다. 이 마찰력은 마찰면의 미끄럼계수와 고력볼트 조임력의 곱에 비례한다. 그러나 너트회전법에 의한 조임시 고력볼트 조임력은 많은 인자에 의해 영향을 받는다. 여유나사길이와 길이-직경비는 고력볼트 조임력을 지배하는 중요한 인자 중에 하나이다. 따라서 본 논문은 여유나사길이와 길이-직경비에 따른 고력볼트 세트(F10T, M16, M20, M22, M24)의 기계적 특성에 관한 실험을 통하여 고력볼트의 정확한 체결 방법을 제공하고자 한다.