• The Plant Pathology Journal
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• 제22권4호
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• pp.364-368
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• 2006

Survival of biocontrol agents and their effective colonization of rhizhosphere are the essential components for successful disease suppression. The effects of hydrogel supplement on bacterial survival and disease control were evaluated in pot and in the field. Addition of 2% hydrogel material to potting soil resulted in significant enhancement of colonization of biocontrol agent Serratia plymuthica A21-4 both in soil and rhizosphere of pepper plants. Rhizosphere colonization of S. plymuthica A21-4 retrieved from 40 days old pepper seedlings indicated 100 times higher bacterial population in hydrogel treated soil than in ordinary pot soil. The pepper plants sown in hydrogelated potting soil showed higher seed germination rate and the better growth of pepper plant than those in ordinary commercial pot soil. Although the suppression of Phytophthora capsid density in the potting soil by treatment of biocontrol agent A21-4 was not significantly different between in hydrogelated soil and ordinary potting soil, the suppression of Phytophthora blight between two treatments was significantly different. A21-4 treatment in hydrogelated potting soil was completely disease-free while same treatment in ordinary potting soil revealed 36% disease incidence. Our field study under natural disease occurrence also showed significantly less disease incidence(12.3%) in the A21-4 treatment in the hydrogelated soil compared to other treatments. Yield promotion of pepper by the A21-4 treatment in the hydrogelated potting soil was also recognized. Our results indicated that hydrogel amendment with biocontrol agent in pot soil would be a good alternative to protect pepper seedlings and increase plant yield.

• Journal of Electrical Engineering and Technology
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• 제10권3호
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• pp.1075-1080
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• 2015

A hybrid electric vehicle (HEV) powertrain has more than one energy source including a high-voltage electric battery. However, for a high voltage electric battery, the average current is relatively low for a given power level. Introduced to increase the voltage of a HEV battery, a compact, high-efficiency boost converter, sometimes called a step-up converter, is a dc-dc converter with an output voltage greater than its input voltage. The inductor occupies more than 30% of the total converter volume making it difficult to get high power density. The inductor should have the characteristics of good thermal stability, low weight, low losses and low EMI. In this paper, Mega Flux^® was selected as the core material among potential core candidates. Different structured inductors with Mega Flux^® were fabricated to compare the performance between the conventional air cooled and proposed potting structure. The proposed inductor has reduced the weight by 75% from 8.8kg to 2.18kg and the power density was increased from 15.6W/cc to 56.4W/cc compared with conventional inductor. To optimize the performance of proposed inductor, the potting materials with various thermal conductivities were investigated. Silicone with alumina was chosen as potting materials due to the high thermo-stable properties. The proposed inductors used potting material with thermal conductivities of 0.7W/m·K, 1.0W/m·K and 1.6W/m·K to analyze the thermal performance. Simulations of the proposed inductor were fulfilled in terms of magnetic flux saturation, leakage flux and temperature rise. The temperature rise and power efficiency were measured with the 40kW boost converter. Experimental results show that the proposed inductor reached the temperature saturation of 107℃ in 20 minutes. On the other hand, the temperature of conventional inductor rose by 138℃ without saturation. And the effect of thermal conductivity was verified as the highest thermal conductivity of potting materials leads to the lowest temperature saturations.

• Elastomers and Composites
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• 제59권2호
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• pp.73-81
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• 2024

In the field of electronic components, the potting material, which is a part of the electronic circuit package, plays a significant role in protecting circuits from the external environment and reducing signal interference among electronic devices during operation. This significantly affects the reliability of the components. Therefore, the accurate prediction and assessment of the lifespan of a material are of paramount importance in the electronics industry. We conducted an accelerated thermal aging evaluation using the Arrhenius technique on elastic potting material developed in-house, focusing on its insulation, waterproofing, and contraction properties. Through a comprehensive analysis of these properties and their interrelations, we confirmed the primary factors influencing molding material failure, as increased hardness is related to aggregation, adhesion, and post-hardening or thermal-aging-induced contraction. Furthermore, when plotting failure times against temperature, we observed that the hardness, adhesive strength, and water absorption rate were the predominant factors up to 120 ℃. Beyond this temperature, the tensile properties were the primary contributing factors. In contrast, the dielectric constant and loss tangent, which are vital for reducing signal interference in electric devices, exhibited positive changes(decreases) with aging and could be excluded as failure factors. Our findings establish valuable correlations between physical properties and techniques for the accurate prediction of failure time, with broad implications for future product lifespans. This study is particularly advantageous for advancing elastic potting materials to satisfy the stringent requirements of reliable environments.

• 한국산림과학회지
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• 제101권3호
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• pp.443-453
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• 2012

본 연구는 아까시나무 유묘에서 뿌리혹 형성에 가장 적절한 배양토의 종류와 토양의 양료 수준을 구명하기 위해 수행하였다. 상업용 상토, 완숙 혹은 미숙 퇴비, 유기질 비료, 산림용 고형비료, 화학비료 등의 토양 첨가물을 이용하여 질소와 인의 수준을 다양하게 조절한 후 포트에 아까시나무 종묘를 식재하여 3개월 간 온실에서 실험을 실시하여 초기 뿌리혹 형성에 적절한 토양 환경을 조사하였다. 피트모스, 질석, 지올라이트를 함유한 상업용 상토는 높은 보수력으로 인해 초기 활착과 건중량 생산에는 적절하였으나 무기 양료 중 질소(0.052%), 인(91 ppm)의 부족으로 인해 뿌리혹 형성에는 부적합하였다. 퇴비는 미숙 퇴비이건 완숙퇴비이건 구별 없이 뿌리혹 형성에 가장 유리했는데, 질소(0.08-0.21%)와 인(141-1,228 ppm)의 함량이 적절하였지만, 칼륨(0.14-1.58 cmol/kg)의 함량은 부족한 편이었다. 화학(복합)비료는 토양 내 질소(0.14-0.21%), 인(406-618 ppm), 칼륨(1.39-3.13 cmol/kg)의 함량을 적절한 수준으로 유지하여 초기 건중량 생산에는 지장을 주지 않았지만 뿌리혹 형성에는 부적절하였다. 산림용 고형비료는 뿌리혹 형성에 적합한 반면, 유기질 비료는 뿌리혹 형성에 적합하지 않았다. 배양토에는 적절한 수준의 질소(0.05-0.2%)와 인(100-600 ppm)이 함유되어 있을 경우에 초기 뿌리혹 형성이 제대로 이뤄졌다. 아까시나무 유묘의 경우 토양의 질소와 인 중에서 질소보다 인이 초기의 뿌리혹 형성을 더 촉진하는 것으로 판단되었다.

• 인간식물환경학회지
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• 제23권5호
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• pp.545-554
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• 2020

Background and objective: Moth orchids in the vegetative stage are suitable for a multi-layer growing environment in a closed-type plant factory which can be a good alternative that can reduce production costs by reducing cultivation time and energy cost per plant. This study was conducted to find out the optimal rhizospheric environment for different irrigation methods without a potting medium and rhizospheric ventilation for the vegetative growth of young Phalaenopsis hybrid 'Blanc Rouge' (P. KV600 × P. Kang 1) and Phalaenopsis Queen Beer 'Mantefon' in a closed-type plant factory system. Methods: The one-month-old clonal micropropagules with bare roots rapped with a sponges were fixed on the holes of styrofoam plates above growth beds, and were watered using the ebb-and-flow (EBB) and aeroponic (AER) methods with Ichihashi solution (0.5 strength) once a day at 06:00 (P) or 18:00 (S), and both (PS). Rhizospheric ventilation (V) was also applied to change the temperature, relative humidity, and CO₂ concentration of the beds. Plants potted into sphagnum moss and watered once a week were used as the control group. Results: After 12 months of treatment, the growth characteristics of the EBB groups were the best among the treatment groups without a medium, but no effect of irrigation timing was observed. V reduced the temperature, relative humidity and CO₂ concentration of the beds. Whereas, EBB+V (ebb-and-flow with ventilation) improved plant growth and reduced the occurrence of disorders and withering. Especially, EBB+V showed a similar performance to the control group. Conclusion: The results indicated that the optimal irrigation method without a potting medium for producing middle-aged potted moth orchids was the EBB system with forced rhizospheric ventilation. Therefore, further studies on the optimal ventilation method and moisture control of the crown need to be carried out to develop the irrigation system without a potting medium for vertical farming in closed-type plant factories.

• 한국농업기계학회:학술대회논문집
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• 한국농업기계학회 2001년도 하계 학술대회 논문집
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• pp.123-128
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• 2001

• The Plant Pathology Journal
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• 제22권3호
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• pp.283-288
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• 2006

Trichoderma harzianum YC459 (Th 459), isolated from sawdust compost, was effective in controlling cucumber and tomato gray mold caused by Botrytis cinerea under controlled and plastic film tunnel conditions. A water suspension of the wettable powder formulation of Th 459 significantly $(P\leq0.05)$ reduced the severity of cucumber gray mold by foliar spraying at all tested concentrations from $10^5\;to\;10^8$ colony forming unit (cfu)/ml in repeated experiments. The control efficacy was maintained at least seven days with the average control value of 70% in cucumber pot tests. Mixing one to eight grams of the granular formulation ($10^8cfu/g$ dry weight) of Th 459 into one liter nursery potting mix at seeding also significantly $(P\leq0.05)$ reduced the severity of cucumber gray mold by suppression of lesion formation three weeks after treatment. Application of mixing granular formulation at seeding in combination with foliar spraying during cultivation provided a more significant reduction $(P\leq0.05)$ of cucumber gray mold than granule mixing or leaf spray alone. The foliar spraying of the formulated wettable powder of Th 459 significantly $(P\leq0.05)$ reduced the infection of tomato fruits by B. cinerea as effective as the chemical fungicide, dichlofluanid, in three plastic film tunnel experiment trials. It is suggested that effective control of gray mold of cucumber and tomato can be provided by both treatment of Th 459 into potting mix and foliar spray through induction of systemic resistance and direct inhibition of the pathogen.

• 한국산업융합학회 논문집
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• 제20권5호
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• pp.351-357
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• 2017

Growing plant in potting media without soil is known as Soilless cultivation. This method is used mostly in greenhouse cultivation to increase horticultural commodities production. Peat moss is commonly utilized as potting media substrate because of its characteristic. However, peat moss price is high because of the quantity of peat moss in nature has been decreased. Recently, most of the research is conducted to find the alternative growing medium to cultivate horticulture plant in potting media. Perlite and rice husk ash were mentioned that had a potent as alternative growing media for seasonal plants to increase agriculture production due to the lack of production area. This study aimed to determine the effect of using different substrate and growth performance of chili. The method used was the soilless cultivation. The chili was planted in the pot with perlite media, rice husk ash media, and peat moss media. The chili was measured after 65 days after planting. The result showed that rice husk ash and perlite were more potentials in chili growth performance than peat moss. Rice husk ash had the significant result of plant height. While, Perlite effect on root length, plant weight, leaf length, and stem diameter. The best alternative for cultivation chili without substrate based on this research was perlite then rice husk ash and peat moss.

• 한국유기농업학회지
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• 제16권3호
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• pp.299-308
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• 2008

유기상토에 툽밥 발효 돈분으로 생산한 분립의 첨가비율을 달리했을 때, 벼의 유식물체 생육에 미치는 영향을 조사하였다. 저면도포 무처리구에서 추청 벼는 분립 20%까지의 혼합비율, 흑미 벼는 분립 10%까지의 첨가비율에서 유식물체의 생육이 양호하였다. 또한 저면도포 처리구에서는 추청 벼와 흑미벼 모두 분립 5% 혼합비율에서 유식물체의 생육이 양호하였다. 저면도포 처리구가 무처리구에 비하여 낮은 분립 첨가비율에서 유식물체의 생육이 양호하였던 것은 뿌리신장에 의하여 토양표면에 시용된 분립으로부터 생육에 필요한 양분의 공급이 이루어졌기 때문으로 추정된다. 또한 장기간 벼를 육묘할 경우에는 유식물체의 생육이 양호하였던 분립의 적정 혼합비율의 범위가 갖는 상토의 이화학성의 유지가 필요하다고 판단된다. 지렁이 분립의 이화학적 특성으로 볼 때, 유기 경종농업에서 토양시용 또는 상토재의 원료로서 유용하게 활용될 수 있을 것으로 판단된다.

• 한국산업융합학회 논문집
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• 제22권1호
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• pp.55-60
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• 2019

Growing plant in potting media without soil is known as Soilless cultivation. This method is used mostly in greenhouse cultivation to increase horticultural commodities production. Peat moss is commonly utilized as potting media substrate because of its characteristic. However, peat moss price is high because of the quantity of peat moss in nature has been decreased. Recently, most of the research is conducted to find the alternative growing medium to cultivate horticulture plant in potting media. Perlite and rice husk ash were mentioned that had a potent as alternative growing media for seasonal plants to increase agriculture production due to the lack of production area. This research aims to determine the growth of in rice husk ash, perlite and peat moss as growing substrates. The method used was the soilless cultivation. The chinese cabbage was planted in the pot with perlite media, rice husk ash media, and peat moss media. The chinese cabbage was measured after 35 days after planting. The result showed that peatmoss was more potentials in chinese cabbage growth performance than rice husk ash and perlite. Peat moss had the significant result of every research parameters such as plant height, plant weight, number of leaves, plant diameter, root length, and root weight. The best alternative for cultivation chinese cabbage without substrate based on this research was peat moss then rice husk ash and perlite.