• 한국초지조사료학회지
• /
• 제25권1호
• /
• pp.65-70
• /
• 2005

This study was conducted to investigate the effect of combine crawler attaching slurry spreader on soil and growth of rye. The performance test at actual field was conducted to test for possibility of practical use. Field test of the slurry spreader was operated in upland and paddy field. Experiments was conducted to compare the effects of the soil damage and crop productivity incorporating Pig slurry by two different types of slurry spreader. In this experiment a slurry spreader using crawler of combine have been designed and developed to enhance the operation in small field and reduce e damage of soil structure. but it was not suitable for transference in long distance. Conventional tractor mounted vacuum is not suitable for $71.6\%$ water condition in the small areas of paddy land. But the slurry spreader using crawler could be controlled the working point and moving by crawler in paddy land of small area. The wheels depths of soil in the supplementary application in the rye field was 4.9 m in tractor mounted spreader. but the wheels depth of crawler attaching spreader was 1.6cm. The dry matter yield of rye was reduced by $12\%$ in supplementary application of slurry due to mechanical damage from passage of the tires. This is particularly noticeable at high soil moisture condition in paddy land. It was concluded that the slurry spreader developed in this study could be successfully used for basal and supplementary application of slurry in rye paddy field.

• 한국산학기술학회:학술대회논문집
• /
• 한국산학기술학회 2004년도 춘계학술대회
• /
• pp.311-314
• /
• 2004

바이오디젤 (지방산 메틸에스테르)을 기반으로 하여 생산된 합성윤활유 베이스에 대한 독성을 분석 평가하였다. OECD 207의 방법에 의거하여 인공토양(artifical soil)에서 300$\~$600 mg의 지렁이를 선별하였다. 0.01, 0.1, 1, 10, 100과 1,000 mg/kg의 각 농도별로 선별된 지렁이를 10마리씩 넣고 수분 $31\~37\%$, 온도 $20{\pm}2^{\circ}C$와 PH 6.0 $\pm$ 0.5를 조절하여 14일간 지렁이의 반수치사농도(lethal concentration when $50\%$ of the population were killed, $LC_{50}$)를 측정하였다. 합성윤활유의 측정 된 반수치사농도($LC_{50}$)는 1,555 mg/kg로 측정되었으며, 유의 확률이 < 0.02로서 유의수준 $5\%$에서 유의함을 알 수 있었다.

• 지질공학
• /
• 제26권3호
• /
• pp.339-352
• /
• 2016

지하 매질의 물리적인 성질을 정확히 평가하기 위한 가장 일반적인 방법은 해당 지점에서 시추하여 채취한 암편을 대상으로 해석한 지질공학적인 실내시험 결과와 시추공 안에 삽입한 탐사 기구를 통해 얻은 지구물리학적인 자료를 함께 복합적으로 해석하는 것이다. 이 연구에서는 충북 증평의 지질학습장으로 예정된 시험부지 중의 한 곳에서 시추공 탐사 대신 수집한 지표 탄성파탐사(굴절법 및 표면파법) 자료로부터 얻은 P파 및 S파 속도구조와 이를 토대로 작성된 포아송 비 단면을 통해 노두에 좁은 폭으로 드러난 암석 환경(적색퇴적암, 회색화산암, 풍화 화산암) 및 접촉선에서 관찰된 단열, 파쇄대가 확인되는지 알아보았다. 또한 탐사 지역에 주로 분포하는 회색 화산암과 적색 퇴적암을 대상으로 지표지질 조사와 실내 지질공학 실험을 수행하였다. 탐사자료에서 평가된 동적 탄성계수 영률은 지질공학 자료의 정적 탄성계수보다 높았다. 실내 시험에서 회색화산암에 비해 공극률이 작고 함수비가 작은 것으로 평가된 적색퇴적암은 추가적으로 건기와 우기에 실시한 전기탐사(비저항 및 자연전위) 결과에서 건우기와 관계없이 상대적으로 전기비저항이 높고 그 변화 폭이 매우 작은 영역으로 확인되었다. 특히 높은 함수비와 공극률을 갖는 풍화된 회색 화산암과 함께 접촉선에서 좁게 발달한 단열 파쇄대가 우기 때의 충전율을 높이는 열린 통로의 역할을 한 것으로 해석된다.

• 한국작물학회지
• /
• 제45권5호
• /
• pp.305-309
• /
• 2000

Ultra-drying [＜5.0% seed moisture content (SMC)] storage technique is a cost-effective storage method for oily seeds. To decide proper ultra-drying condition for soybean seeds, drying rate was compared three silica gel to seed ratios, two seed sizes with varietal difference, two kinds of container, and three seed amounts per container under :t 23$\pm$1$^{\circ}C$. When the relative humidity (RH) was reduced at the rate of less than 0.1 % a day, silica gel was replaced with dry one by 47 days. Higher silica gel to seed ratios (3:1 and 2:1) dried faster than lower ratio (1:1) until 28 days, but not after 43 days of drying. Also, large seeded variety was dried faster than small seeded variety. Kinds of container and seed amounts per container didn't show differences in drying of soybean seeds. After completion of ultra-drying, percentage germination by standard germination test (SGT) was not different among silica gel to seed ratios, kinds of container, and seed amounts per container, except among seed sizes (varieties). Before SGT, soybean seeds were premoistened using saturated ${CaCl}_2$ for 48 hours and ${NH}_4$Cl for 24 hours in desiccators. To compare germinability between ordinary-dried seeds and ultra-dried seeds, the seeds of seven soybean varieties, which were varying in size from 8.1 to 34.9 g per 100 seeds, were dried using same amount of silica gel under 23$\pm$1$^{\circ}C$. After completion of 76 days of drying, SMCs were reduced to 3.13-3.45% from 7.86-8.82%. SMC after completion of drying was not correlated with 100-seed weight (r=0.556). Before germination tests, soybean seeds were premoistened using saturated salt solutions. Percentage germination was higher with ultra-dried seeds than ordinary-dried seeds in SGT and higher with ordinary-dried seeds than ultra-dried seeds in AAT at the beginning of storage and after 6 months storage, but general trend of percentage germination was not observed among varieties classified by 100-seed weight. From these results, we concluded that further studies are needed to improve ultra-drying storage method for soybean seeds.

• 한국산림과학회지
• /
• 제70권1호
• /
• pp.45-54
• /
• 1985

본(本) 연구(硏究)는 균근균(菌根菌) 접종묘(接種苗)[모래밭버섯균(菌)(Pisolithus tinctorius), 사마귀버섯균(菌)(Thelephora terrestris)]와 무처리(無處理) 묘목(苗木)을 이용(利用)하여 인산수준(燐酸水準)과 수분(水分) 조건(條件)에 따른 묘목(苗木)의 생장(生長) 및 양료흡수(養料吸收)에 미치는 균근(菌根)의 효과(效果)를 측정(測定) 조사(調査)한 것으로 그 결과(結果)는 다음과 같다. 1) 근원경(根元徑) 생장(生長)은 습구(濕區)에서가 건구(乾區)에서보다 2.7배 생장(生長)이 컸다. 2) 건구(乾區)에서는 모래밭버섯균(菌) 처리(處理) 묘목(苗木)의 물질생산(物質生産)은 평균 26% 증가하고, 무처리(無處理) 묘목(苗木)은 72% 증가하여 모래밭버섯균(菌) 처리(處理) 묘목(苗木)이 무처리(無處理) 묘목(苗木)보다 순물질생산량(純物質生産量)이 적었다. 3) 순물질생산량(純物質生産量)에 있어서 건구(乾區)에서보다 습구(濕區)에서 4배 증가했으나 인산(燐酸) 시비수준(施肥水準)은 순물질생산량(純物質生産量)에 영향이 없었다. 4) 모래밭버섯균(菌) 처리(處理)는 습구(濕區)에서 질소(窒素), 인산(燐酸) 및 가리(加理)의 양과(養科) 흡수(吸收)의 효과(效果)가 뚜렷이 나타났는데 무처리(無處理) 묘목(苗木)에 비하여 각각 1.9배, 1.8배, 1.5배의 흡수(吸收)가 촉진(促進)되었다. 5) 모래밭버섯균(菌) 처리(處理) 묘목(苗木)은 인산(燐酸) 시비수준(施肥水準)이 증가함에 따라 인산(燐酸) 흡수량(吸收量)이 많았으나 무처리(無處理) 묘목(苗木)에서는 인산(燐酸) 시비수준(施肥水準)의 증가가 인산(燐酸) 흡수(吸收)에 영향(影響)을 미치지 않았다. 6) 모래밭버섯균(菌) 처리(處理) 묘목(苗木)은 인산(燐酸) 시비수준(施肥水準)이 증가함에 따라 가리(加理)의 양과(養科) 흡수(吸收)를 촉진(促進)시켰다.

• 한국지하수토양환경학회지:지하수토양환경
• /
• 제21권2호
• /
• pp.1-7
• /
• 2016

Ferrous slag is a by-product from steel making process and waste concrete is generated from construction activities. Large part of ferrous slag and waste concrete are recycled as construction materials. However, Ca²⁺ leaching out of ferrous slag and waste concrete in the water-contacting environment can cause a strength change. Strength can be reduced due to the dissolution of solid form of CaO which is one of the main contents of ferrous slag and waste concrete. On the other hand, strength can be enhanced due to the pozzolanic reaction of cementitious components with water. In this study, steelmaking slag, blast furnace slag, and waste concrete were aged by exposure to raining events, and the change of their compaction and shear strength characteristics was investigated. Optimum moisture content of all materials used in this study increased with aging period while maximum dry unit weight slightly decreased, implying that the relative contents of fine particles increased as the CaO solid particles were dissolved. Internal friction angle and shear strength of recycled materials also increased with aging period, indicating that the materials became denser by the decrease of void ratio attributed to the fine particles generated during the weathering process and the development of cementitious compounds increasing the bonding and interlocking forces between the particles. The results of this study demonstrated that mechanical strength of recycled materials used as construction materials has little chance to be deteriorated during their service life.

• 한국농공학회지
• /
• 제31권2호
• /
• pp.66-81
• /
• 1989

The characteristics of resilient modulus(Mr) which dominates the life of pavement and the design of pavement were investigated on the test specimens which were cement treated and non-treated of the three different soil types. The results are summarized as follows : 1. The resilient modulus was decreased by increasing the cyclic deviator stress ($\sigma$d) , especially the resilient modulus was gradually decreased or sometimes increased when the value of ad was greater than 0.75- 1. 0kg/cm$^2$. 2. The resilient modulus was increased by increasing the homogeneous confined stress ($\sigma$do) and such phenomena were distinct on the coarse soils. 3. The resilient modulus was increased by increasing the ratio of confined stress(Kc), and this phenomena were eminent on the coarse soils too, and the higher permanent strain was showed by increasing the value of Kc. 4. In the drained cyclic triaxial compression test, the value of ad, Kc, and (Oho) was introduced by the following interrelated equations which were similar to the Mr model of Cole. Kcn/Mr=K1(J$_2$/ $\tau$oct)K2 ............. (coarse soli) Mcn/Mr=K3($\sigma$dp/ $\tau$f)k4 ...............(fine soils) 5. The stress path was not much affected by the value of Mr, however, moisture content, dry desity, and contant of fines affected the value of Mr. 6. In the soil-cement specimens, the resilient compression strain($\varepsilon$d) was decreased by the increment of the $\sigma$ho, and Mr was decreased by increasing the $\sigma$d 7. In the flexible pavement. the cement treated layer should be designed not to fail by the fatigue before the designed traffic load, and actually the pavement could cover the traffic load to a certain extent under the post-crack phase, therefore farther studies on this phenomena' are required in the design analysis. 8. The finite element computer program (ANALYS) was used for displacement analysis of pavement containing the cement-treated layer, The result showed that the program used for this analysis was proved to be usable.

• Journal of Biosystems Engineering
• /
• 제34권5호
• /
• pp.351-357
• /
• 2009

This study was conducted to verify the simulation model through the drying test, and investigate effect of factors, such as temperature of drying air, airflow rate, and velocity of the airflow, on the drying. The low temperature drying simulation model was developed based on the circulation dry simulation model presented by Keum et al. (1987), and by modifying low temperature thin layer drying model, equilibrium moisture content model, latent heat of vaporization model, and crack ratio prediction model. The heat pump and experimental dryer with a capacity of 150kg were used for the test. The RMSE between the predicted and measured value was 0.27% (drying temperature), 0.15% (crack ratio), and 2.08% (relative humidity), so the relevance of the model was verified. In addition, the effect of drying temperature, airflow rate, and velocity of the airflow on the drying was examined. The experimental results showed that the crack ratio at drying temperature of $25{\sim}40^{\circ}C$ was allowable. Moreover, at below $30^{\circ}C$, variation of the crack ratio was slight, but drying time was delayed. Given these results, the drying temperature of over $30^{\circ}C$ was effective. As the airflow rate increased, required energy dramatically increased. Whereas drying rate slowly increased, so loss of drying efficiency was caused. Considering these results, the dryer needed to be designed and adjusted to lower than $30\;m^3/min{\cdot}ton$. As velocity of the airflow increased, required drying energy increased when the velocity of the airflow was over $5\;m^3$/hr, while crack ratio and drying rate showed little variation.

• 한국구조물진단유지관리공학회 논문집
• /
• 제12권2호
• /
• pp.149-155
• /
• 2008

최근 교통소통의 필수적인 수단으로 많은 도로가 건설 중에 있으며 기 시공된 도로 등은 차량의 통행과 기후 등의 여러 요인에 의해 내하력이 저하되고 있다. 본 연구에 적용된 지반의 흙의 종류와 소성지수 그리고 비중은 각각 SC, 12.2%, 2.66이였으며 최대건조단위중량, 최적함수비, 수정CBR은 각각 $1.895g/cm^2$ (수정다짐 D), 13.6%, 16.2%였다. 이러한 지반조건에서 동적콘관입시험의 관입지수로부터 추정한 CBR과 소형 FWD시험의 동적변형계수로부터 환산한 정적변형계수 사이에는 상관계수가 0.90으로 높은 상관성을 나타내었다.

• 대한토목학회논문집
• /
• 제33권3호
• /
• pp.1037-1047
• /
• 2013

다짐 에너지에 따른 노반 성토재의 탄성파 속도변화 특성을 규명하기 위하여 다양한 위치에서 채취한 시료를 이용하여 실내 다짐 시험, 실내 탄성파 측정 시험, 현장 탄성파 측정 시험을 실시하였다. 함수비 변화에 따른 압축파와 전단파 속도 변화 곡선은 다짐 곡선과 유사한 형태를 보인다. 다짐에너지가 100 %이상 되는 조건에서는 다짐 에너지가 증가하더라도 습윤 측의 다짐곡선과 탄성파 속도 곡선에 큰 변화가 없다. 압축파의 경우 건조 측에서 건조단위중량이 증가함에 따라 압축파 속도가 선형적으로 증가하는 양상이 나타나지만, 습윤 측에서는 건조단위중량이 증가함에 따라 지수함수의 형태로 압축파 속도가 비선형적으로 증가한다. 현장 시험으로 측정한 탄성파 속도는 구속압이 증가함에 따라 증가하며, 압축파 속도보다는 전단파 속도가 다짐 에너지 수준에 보다 민감하게 변화한다.