• 한국농공학회지
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• 제22권3호
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• pp.46-59
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• 1980

This study was conducted to obtain the most effective distribution of grain size and the optimum lime content for lime-soil stabilization. To achieve the aim, the change of consistency, the characteristics of compaction and unconfined compressive strength were tested by adding of 0, 4, 6, 8, 10 and 12 percent lime by weight for all soils adjusted by given ratios of sand to clay. The results obtained were as follows; 1. There was a tendency that the plasticity index of lime-soil mixture was decreased by increasing the amount of lime, whereas the liquid limit was varied irregularly and the plastic limit was increased. 2. With the addition of more lime, the optimum moisture content of lime-soil mixture was increased, and the maximum dry density was decreased. 3. The optimum lime content of lime-soil mixture was varied from soil to soil, and the less amount of small grain size, the less value of optimum lime content. 4. The optimum distribution of grain size for lime-soil mixture was in the soil, having the ratio of about 60 percent of cohesive clay and about 40 percent of sand by weight. 5. In the soil having fine grain size, the effect of curing appeared for long periods of time, whereas the increasing rate of unconfined compressive strength was great on the soil of coarse grain size in the earlier stage of curing period.

• Journal of Biosystems Engineering
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• 제9권2호
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• pp.65-73
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• 1984

While most of researches on the performance of high temperature grain dryer have dealt mainly with improving dryer capacity and drying speed during the last twenty years, energy efficiency, in fact, has not been emphasized. Current fuel supplies and energy cost have shifted the emphasis to reducing the energy consumption for grain drying while maintaining dryer capacity and grain quality. Since the energy input for drying is relatively large, the recovery and reuse of at least part of the exhaust energy can significantly reduce the total energy consumption in existing drying systems. Unilization of exhaust heat in grain dryer either through direct recycling or by a thermal coupling in heat exchanger have been subject of a number of investigators. However, very seldom research in Korea has been done in this area. Three drying tests(non-recycling, 0.22 recycle ratio, and 0.76 recycle ratio)were performed to investigate the thermal efficiency and heat loss factors of continuous flow type dryer, and to analyze the effect of recycle ratio (weight of exhaust air recycled/total weight of input air) on the energy requriements for rough rice drying. The test results showed that when the exhaust air was not recycled, the energy lost from furnace was 15.3 percent of input fuel energy, and latent and sensible heat of exhaust air were 61.4 percent and 11.2 percent respectively. The heat which was required in raising grain temperature and stored in dryer was relatively small. As the recycle ratio of exhaust air was increased, the drying rate was suddenly decreased, and thermal efficiency of the kerosene burner was also decreased. Drying test with 0.76 recycle ratio resulted in 12.4% increase in fuel consumption, and 38.4% increase in electric power consumption as compared to the non-recycled drying test. Drying test of 0.22 recycle ratio resulted in 6.8% saving in total energy consumption, 8.0% reduction in fuel consumption, and 2.5% increase in electric power consumption as compared to the non-recycled drying test.

• 한국대기환경학회지
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• 제2권1호
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• pp.11-21
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• 1986

The study was performed to investigate the effects of gaseous imission of sulfur dioxide and hydrogen fluoride on the growth of rice plant under stressed field conditions. The plants were cultivated in normal paddy fields where are 88 industrial plants operating with 285 smoke stacks emitting pollutants. There has been a number of reported studies (1, 3, 11, 19, 20) which deal with rice plant damages by air pollution under a simulated exposure experimental condition. Furthermore, these experiments were conducted to examine effects of a single pollutant on the plant. Furthermore, these experiments were conducted to examine effects of a single pollutant on the plant. In korea, however, there is no study reported in literature with respect to the in-situ dose-response relationship between rice pant reduction in yields and air pollution. This study is specifically dealt with multiple effects of sulfur dioxde and hydrogen fluoride on various plant growth indicators such as leaf damage, culm height, weight of grain, panicles per hill, spikelets per panicle and percent fertility.It appears that there is a good correlation between ambient concentrations of sulfur oxides and sulfur contents found in leaves with an average correlation coefficient of 0.868 within a 1% significance level. It is interesting to note that a better multiple correlation was found between percent leaf damage and sulfur and fluoride contentd found in leaf with a significance of 1% level. The yearly correlation coefficient ranges from 0.963 to 0.987 with an average being 0.971. It is, therefore, believed that a percent leaf damage may serve as a single indicator of pollutional damages to rice plant cultivating in fields. Regarding other factors to the diminution of rice plant growth in polluted atmosphere, it appears that a significant correlation to culm length and dry weight of grain with a 1% significance level whereas T/R ratio has a good correlation with lead damage within 5% significance level. An evaluation of data observed has demonstrated that both panicles per hill and percent fertility are significantly affected by air pollutants. As expected, hydrogen fluoride has more effects than sulfur oxide. It is, however, interesting to note that spikelets per panicles has slightly been affected while no indication of effects on 1000-grain-weight has been observed. This may lead to a conclusion that a reduction in yield of rice under polluted field conditions may have more been caused by the diminution of panicles per hill and percent fertility rather than by the diminution of spikelets per panicle and grain weight.

• 농약과학회지
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• 제19권4호
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• pp.394-398
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• 2015

본 연구는 잎집무늬마름병에 대한 약제방제수준을 설정하기 위하여 오대벼를 공시하여 시험을 수행하였다. 잎집무늬마름병 발병정도에 따라 수량에 미치는 관계를 분석하였으며, 수량 구성 요소인 주당 이삭수, 이삭당 립수, 등숙률, 천립중과의 관계를 분석하였다. 그 결과 발병주율에 대한 수량과의 관계는 r = -0.93, 이삭당 립수 r = -0.66, 등숙율은 r = -0.77로 고도의 유의성 있는 부의 상관이 있었으나, 주당 이삭수와 천립중은 유의한 상관이 인정되지 않았다. 따라서 본시험에서는 발병과 상관이 높은 수량에 대하여 경제적 방제수준은 발병주율 7.8%로 설정할 수 있었다.

• 한국작물학회지
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• 제47권6호
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• pp.443-447
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• 2002

참깨 재배조건에 따른 생육과 수량 및 품질 차이를 구명하고자 수행한 연구결과는 다음과 같다. 1. 비닐하우스 재배가 노지 재배에 비해 개화기가 빠른 반면 성숙기가 늦어 생식생장기간이 길었다. 또한 경장과 착삭부위장이 매우 길었다 한편 주당삭수가 많고 천립중이 무거워 수량이 57%가량 많았다. 2. 비닐하우스 재배에서는 6월 8일 파종구가 5월 9일 파종 구에 비해 착삭부위장이 길었다. 그리고 주당삭수가 많고 천립중이 무거웠다. 또한 착삭 상단부위 등숙율이 높고 착삭 중, 하단부위 천립중이 무거우나 수량은 비슷하였다. 3. 노지 재배에서는 5월 9일 파종구가 6월 8일 파종구에 비해 유효분지수와 주당삭수가 많았다. 그러나 착삭 상, 중단부위의 등숙율이 낮고 천립중이 가벼워 수량은 비슷하였다. 4. 종실의 $L^*$값은 재배조건에 따라 차이가 없었고 $a^*$값은 비닐하우스 재배에서 높았으나 $b^*$값은 노지 재배에서 높게 나타났다 그리고 파종기간 색차($\Delta E^*{ab}$)는 노지 재배에서 가장 높게 나타났다. 5. 비닐하우스 재배에서는 수용성 성분인 세사미놀 배당체 함량이 높고, 노지 재배에서는 세사민과 세사몰린 함량이 높게 나타났다.

• 한국작물학회지
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• 제35권3호
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• pp.195-200
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• 1990

수도주요생육시기별 고온처리(주간 : 37$\pm$2$^{\circ}C$, 야간 : 27$\pm$2$^{\circ}C$) 및 고온시 물관리방법이 생육 및 수량에 미치는 영향을 구명하여 고온장해대책을 위한 기초자료로 활용코자 본 시험을 실시하여 다음과 같은 결과를 얻었다. 1. 주요생육시기별 고온처리의 영향은 생육시기에 관계없이 공시품종 모두 무처리에 비해 지상부 건물중이 감소하고 부근량이 증가하며 식물체내 전 질소함량이 감소하고 규산함량이 증가하였다. 2. 수량 및 수량구성요소에 미치는 고온의 영향은 수당발화수는 감수분열기에, 임실비율 및 등숙율은 출수기에 그리고 천립중은 등숙기에 가장 저하되었으며 고온에 의한 수량감소정도는 출수기에 가장 컸으며 그 다음은 등숙기 >감수분열기 >유수형성기 >최고분염기 >분염기 순이었다. 3. 물관리방법에 따른 답면수온의 변화는 상시담수는 최적수온 보다 주간 1.1$^{\circ}C$, 야간 3.7$^{\circ}C$ 높았으며 흘러대기 물관리방법에 의하여 최적수온(주간 : 31$^{\circ}C$, 야간 : 21$^{\circ}C$)으로의 조절이 가능하였으며 이에따라 초장이 단축되고 건물중 및 신근발생율이 증가하였다. 4. 주간흘러대기 야간담수 및 화야간흘러대기 물관리 방법은 상시담수구보다 수당발화수, 등숙율 및 천립중 등의 수량구성형질의 향상을 도모하여 4-8%의 증수효과가 있었다.

• 한국농공학회지
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• 제27권2호
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• pp.57-71
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• 1985

The characteristics of compaction and unconfined compressive strength were investigated by mixing with lime to all soils adjusted by given percentages of two kinds of clays to sand to obtain the most effective distribution of grain size and the optimum lime content for soil stabilization. In addition, unconfined compressive strength and durability tested by adding of sodium metasilicate, sodium sulfate, sodium carbonate, sodium gydroxide and magnesium oxide to lime-soil mixture mixed with 8 percent lime to adjusted soil having the mixing percentage of 60 percent of cohesive black clay and 40 percent of sand by weight to get the effect and the optimum content of chemicals. The results obtained were as follows; 1.With the addition of more lime, the optimum moisture content was increased, and the maximum dry density was decreased, whereas the more the amount of clay and the less was the maximum drt density. 2. In the soil having more fine grain size the unconfined compressive strength was larger in the earlier stage of curing period, in accordance with the longer period, the mixing percentages of sand to clay showing the maximum unconfined compressive strength, on the basis of 28-day strength, were 60% : 40% (black clay) and 40% : 60% (brown clay) respectively. 3. The reason why the soil adjusted with black clay was remarkably bigger in the unconfined compressive strength than ones adjusted with brown clay for all specimen of lime-soil mixture was the difference in the kind of clay, the amount of chemical compositions the value of pH. Black clay was mainly composed of halloysite that reacted with lime satisfactorily, whereas the main composition of brown clay was kaolinite that was less effect in the enhance of unconfined compressive strength. Also the difference of unconfined compressive strength was because black clay was larger in the amount of composition of calcium oxide and magnesium oxide in the value of pH affecting directly on the unconfined compressive strength of lime-soil mixture than brown clay. 4. In the lime-soil mixture mixed with 8 percent of lime to soil that mixing percentage of sand to black clay was 60% : 40%, on the standard of 7-day strength, the effect of chemical was arranged in the order of magnesium oxide, sodium carbonate, sodium sulfate, sodium hydroxide and sodium metasilicate. 5. The optimum amount of chemical being applicable to the maximum unconfined compressive strength of lime-chemical-soil mixture was 1 percent by weight for air dry soil in the case of adding sodium carbonated and 0.75 percent on sodium hydroxide, the unconfined compressive strength was increased continuously with increase of the amount of chemical up to 2 percent of chemical content is the lime-chemical-soil mixture added sodium metasilicate, sodium sulfate and magnesium oxide. 6. It was considered that the chemical played and accelerant role of early revelation of strength because the rate of increase of unconfined compressive strength of all of lime-chemical-soil mixtures was largest on the 7-day cured specimen. 7. The effect of test on freezing and thawing after adding suitable amount of chemical on the lime-soil mixture mixed with 8 percent of lime to soil that mixing percentage of sand to black clay was 60% : 40% was arranged in the order of magnesium oxide, sodium carbonate, sodium sulfate, sodium metasilicate and sodium hydroxide.

• 식물병연구
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• 제29권2호
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• pp.137-144
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• 2023

Exserohilum turcicum is a fungus that causes northern corn leaf blight (NCLB) and has deleterious effects on maize production globally. Therefore, it is prudent to mitigate the effects of NCLB using genetic diversity. The objective of this research was to assess the severity of NCLB disease on the growth and yield of various maize genotypes. A randomized complete block design field experiment, replicated three times, was conducted to evaluate the effect of E. turcicum on 10 maize hybrids. Percent disease index, plant height, and leaf area were recorded at the silk stage. Cob weight, grain fresh weight, and grain yields were determined at harvest maturity. All measured parameters were significantly different (P<0.05) between the maize hybrids. Of the 10 genotypes, four (PAN 4R-528R, PAN 4R-728BR, PAN 3R-724BR, and P1788BR) were susceptible, five (DKC74-74BR, PAN 5R-582R, PAN 5R-890R, PAN 5R-854R, and PAN 5R-590R) were moderately susceptible, and one (DKC80-40BR) was moderately resistant. DKC80-40BR exhibited greater cob weight, while DKC74-74BR was superior in all other plant growth and yield components. Interestingly, although not significant (P>0.05) and high, maize growth and yield parameters had negative correlations with disease incidence, except for grain fresh weight. Therefore, DKC80-40BR may be selected for cultivation in areas prone to NCLB to reduce maize susceptibility to the disease, while DKC74-74BR may improve crop performance. These hybrids could be considered as potential sources of resistance or tolerance to NCLB for further validation by plant breeders.

• 한국농공학회지
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• 제26권2호
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• pp.59-68
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• 1984

The Purpose of this study was to investigate the effect of the change in misture content on some physical properties of grains, and some relations amont the properties. Materials included ere rough rice, brown rice, barley and wheat with the range of moisture content of 6~26 percent, 7~25 percent, 10~24 percent and 6~22 percent, respectively. Kernel dimension, sphericity, kernel weight, and volume were included as the physical properties of the grains. The results obtained are summarized as follows; 1. The ratio of grain length to the thickness was in the range of 3.59~4.16 for rough rice(Indica type), 2.98~3.27 for rough rice(Japonica type), 3.25 for brown rice (I.T.), 2.14~2.38 for brown rice(J.T.), 2.92~3.13 for barley and 2.10~2.21 for wheat, respectively. 2. The sphericity was found to be 42 percent for rough rice(I.T.), 48 percent for rough rice(J.T.), 52 percent for brown rice(I.T.), 62 percent for brown rice(J.T.), 45 percent for barley and 61 percent for wheat, respectively. 3. The kernel weight of grains was linealy increased with the increase of moisture content. At a specified moisture centent of 14 percent, the kernel weight was shown to be in the range of 4.72${\times}10^{-5}$~3.58${\times}10^{-5}$kg for wheat, 3.60${\times}10^{-5}$~3.12${\times}10^{-5}$kg for barley, 2.80${\times}10^{-5}$~2.35${\times}10^{-5}$kg for rough rice, and 2.24${\times}10^{-5}$~1.82${\times}10^{-5}$kg for brown rice, respectively. 4. The kernel volume was linearly increased with increase of moisture content. The rate of increase was significantly low for rough rice in comparison with the remaining grains. The kernel volume, at a specified moisture content of 14 percent, was in the range of 3.51${\times}10^{-8}$~2.76${\times}10^{-8}m^3$ for wheat, 2.84${\times}10^{-8}$~2.43${\times}10^{-8}m^3$ for barley, 2.93${\times}10^{-8}$~1.97${\times}10^{-8}m^3$ for rough rice, and 1.61${\times}10^{-8}$~1.29${\times}10^{-8}m^3$ for brown rice, respectively. 5. The kernel volume of grains was found to be related to the length, width, thickness and kernel weight as a exponential function. The kernel volume was shown to have correlation coefficient to the length factor rough rice and barley which were of low sphericity, while the width factor was predominant for brown rice and wheat which was of high sphericity.

• Journal of the Korean Wood Science and Technology
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• 제48권5호
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• pp.722-731
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• 2020

The purpose of this research is to determine the efficiency of impregnation using phenol formaldehyde resin to enhance Falcataria wood's stability and better mechanical properties. Impregnation process was carried out after moisture content stabilized at 12% on samples with a dimension of 20 mm × 20 mm × 300 mm at various concentrations and pressure time. Dimensional stability was evaluated by thickness swelling (TS) and anti-swelling efficiency (ASE) and the young's modulus was conducted according to BS 573. The mechanical properties and dimensional stability of impregnated wood were evaluated. Dimensional stability and mechanical properties of Falcataria wood were successfully increased after impregnation. PF impregnation can improve the mechanical properties and the density from 0.26 g/㎤ to 0.30 g/㎤ even with only 10% of weight percent grain. Dimensional stability increases with increasing resin concentration and time pressure. The highest increase in mechanical properties was found at a higher concentration of PF. The penetration of PF into the wood's cell darkens the color of impregnated wood.