• 한국초지조사료학회지
• /
• 제42권2호
• /
• pp.89-95
• /
• 2022

본 시험은 남부지역에서 파종간격에 따른 이탈리안 라이그라스 종자의 생산성 변화를 구명하기 위하여 수행되었다. 이탈리안 라이그라스(Lolium multiflorum Lam.) '그린콜' 품종을 2020년 가을에 경남 진주지역에 파종하였다. 처리는 3처리의 파종간격(20cm, 30cm, 및 40cm)을 두고 난괴법 3반복으로 수행하였다. 시험구의 파종은 2020년 10월 17일에 하였으며 수확은 출수일로부터 약 60일째인 2021년 5월 31일에 하였다. 출수기는 평균 4월 27일로 처리 간에 차이는 없었다. 초장은 30cm 파종간격에서 유의적으로 길었고 20cm 처리구에서 가장 짧았다. 내도복, 내병성 및 내한성은 처리간에 유의적인 차이가 나타나지 않았지만, 도복이 심한 편이었다. 이삭의 길이는 40cm구에서 가장 길었고 이삭당 종자수는 20cm 파종구에서 가장 많았으나 처리간 유의성은 없었다. 종자 수량은 20cm 파종간격에서 2,180 kg/ha로 가장 많았으며 간격이 넓어질수록 줄어들었다. 종자 및 짚의 건물함량은 평균 44.90% 및 45.51%으로 나타났으며 처리간 유의적인 차이는 나타나지 않았다. 채종 후 남은 짚의 수량은 건물기준 평균 7,506 kg/ha로 나타났으며 20cm 파종간격에서 높았다. 이상의 결과를 종합하여 볼 때 남부지역에서 가을 파종을 통한 이탈리안 라이그라스 종자생산 시 20cm 간격으로 파종하는 것이 가장 유리한 것으로 나타났다.

• International Journal of Industrial Entomology and Biomaterials
• /
• 제17권2호
• /
• pp.201-203
• /
• 2008

A field study on self trap cropping system in controlling tukra mealy bug Maconellicoccus hirsutus Green) incidence on mulberry (Morus spp.; V-1 variety; $3'{\times}3'$ spacing) gardens was undertaken in selected sericulture farmers' mulberry gardens of Pydeti village (Parigi Mandal, Anantapur District, Andhra Pradesh, India). The study was conducted for three years (2004, 2005 and 2006). Four treatments (T0; control/no treatment, T1; self trap cropping rows with 10 row interval, T2; self trap cropping rows with 10 row interval and treating these rows only with 0.5% neem oil emulsion and T3; self trap cropping rows with 10 rows intervals and treating all the mulberry rows including self trap cropping rows with 0.5% neem oil emulsion) were considered. The results indicated that the incidence increased in T0 and T1 while the same suppressed in T2 and T3. The suppression (%) of tukra incidence between T2 and T3 was not significant. Hence, T2 only was recommended to farmers as its economical viable practice. The results are discussed based on the importance of tukra, its suppression and cost of treatment.

• 대한기계학회:학술대회논문집
• /
• 대한기계학회 2003년도 추계학술대회
• /
• pp.181-186
• /
• 2003

An experimental study has been conducted to measure the temperature fields for two and three staggered rows of the rectangular shaped-holes with high turbulence intensity. 10 % turbulence intensity is obtained by installation of two kinds of grids which have different shapes. One grid which is installed at 30d upstream from center of 1st row of holes is composed of vertical cylinders of which diameter is 10 mm and center to center distance is 18 mm. The other installed 15d apart to upstream from center of 1st row of holes which has square pattern is constructed of 3 rum square bars and bar spacing is 25 mm. Temperature fields are measured by using a thermocouple rake which is attached on three-axis traversing system. The results show that the overall values are decreased and the thicker film of coolant is fanned downstream of rows of holes for high mainstream turbulence intensity.

• Journal of Biosystems Engineering
• /
• 제27권5호
• /
• pp.417-424
• /
• 2002

This study was conducted to develop a vehicle, leading or following a worker at a certain distance to assist laborious transporting works in greenhouses. A prototype vehicle was tested in the practical field conditions using a developed control algorithm. Results of this study were summarized as following: 1. The sensing device consisted of infrared sensors was attached to the front of the vehicle and turning following algorithm was developed to make the vehicle turned as it follows a worker simultaneously. 2. The measured average power consumptions were 110W and 89W, equivalent to 5.2-6.4 hrs battery durations, at low speed with and without the maximum payload, respectively. 3. Results of the travel tests showed that the deviations from the center of row spacing were $\pm$100 mm along the ridge and $\pm$85 mm along the hydroponic bed in the greenhouse. Therefore, the worker-following transport vehicle was feasible to travel along the row without collision in the greenhouse.

• 한국지반공학회논문집
• /
• 제32권1호
• /
• pp.5-18
• /
• 2016

본 연구에서는 모형실험을 통해 균질모래지반에 매설된 횡력을 받는 무리말뚝의 수평저항력을 산정하는데 가장 큰 영향을 주는 배면토의 저항형태를 파악하였다. 저항거동 형태는 회전절점, 쐐기 파괴각, 쐐기 날개각으로 파악하였다. 실험은 지반의 상대밀도, 말뚝의 폭, 말뚝의 간격과 배열을 달리하여 수행하였다. 그 결과 직렬말뚝에서의 지반거동 양상은 전열과 중간열이 같았고 후열의 경우 전열과 중간열 보다 작은 값을 나타내었다. 병렬말뚝의 경우 지반거동 양상이 단독말뚝과 같게 나타났다. 실험 결과를 바탕으로 회전절점, 쐐기 파괴각, 쐐기 날개각 산정 값 들을 식으로 제안하였다.

• Journal of Biosystems Engineering
• /
• 제30권4호
• /
• pp.220-228
• /
• 2005

This study was conducted to investigate the main factors that contain a rotating velocity ratio between wheel and conveyor belt, a tilt angle of conveyor belt and a rotating velocity of a dick cutter for mechanization of Chinese leek harvest. In the survey on the cultivation of Chinese leek, row spacing of 350 m and cutting height of 10 mm from the ground were set up for field tests. Test equipment was designed to cut, pick up and convey Chinese leek one row by one row. From the results of material tests, pick-up height of conveyor belt was set up at $60\~90m$ from the bottom, and the strain and stress at rupture of Chinese leek was 0.487 m/m and 0.01078 MPa. An elastic coefficient of the rubber (Neoprene) of conveyor belts was 1.1077 under the strain of 0.3 nym. from the results of field tests, the tilt angle of conveyor belt was the range of $25^{\circ}\~30^{\circ}$ under consideration far space of container, the velocity ratio between vehicle and conveying belt was 1 to 2.4~1.7 at 0.1~0.3 m/s of vehicle, and optimum rotating velocity of the disk cutter was 34.8 m/s or more under consideration for soil friction.

• 한국지반공학회논문집
• /
• 제15권6호
• /
• pp.239-249
• /
• 1999

본 논문에서는 측방변형을 받는 수동 군말뚝의 거동특성을 연구하기 위해 말뚝의 휨강성, 말뚝중심간격, 상대밀도와 두부구속조건을 변화시킨 단독말뚝과 말뚝 중심간격이 말뚝직경(D)의 2.5, 5.0, 7.0배가 되는 1열 군말뚝에 대한 모형실험을 실시하였다. 실내모형실험은 주문진 표준사와 화강 풍화토에 근입된 수동말뚝에 직사각형 형태의 측방변위를 점진적으로 가하여 주문진 표준사에 대해 총 32회, 화강풍화토에 대해 총 16회의 실험을 실시하였다. 주문진 표준사에 대해서는 알루미늄과 PVC말뚝을, 화강풍화토에 대해서는 PVC 말뚝만을 사용하였다. 그 결과 수동말뚝에서 발생하는 최대 휨모멘트와 말뚝변위는 말뚝의 휨강성, 말뚝중심간격, 지반조건, 두부구속조건에 따라 크게 영향을 받는다는 것을 알 수 있었다. 1열 군말뚝은 두부 구속조건에 상관없이 말뚝중심간격 7.0D 이하에서 그룹효과가 나타났으며, 7.0D에서 거의 단독말뚝과 같은 거동을 보임을 알 수 있었다. 말뚝의 간격이 좁아짐에 따라 말뚝의 변위와 휨모멘트 모두 감소하였다. 아울러 말뚝의 휨강성이 클수록 휨모멘트는 증가하나 변위는 감소하고, 상대밀도가 클수록 휨모멘트와 변위는 커지는 경향을 보였다. 상대밀도에 대한 휨모멘트의 크기 변화는 고정단에 의한 실험보다 자유단에 의한 실험에서 더 크게 나타났다.

• 한국작물학회지
• /
• 제44권4호
• /
• pp.364-367
• /
• 1999

Swordbean was recently introduced to Korea, and cultural technique for stable production, e.g. optimum seeding date and planting space, has not been established. This experiment was conducted to elucidate the changes of growth characteristics, yield components, and yield as affected by different seeding dates and planting spaces. Days to flowering was shortened by 4∼28 days as seeding was delayed. Stem diameter, number of pods per plant, number of seeds per plant, 100-seed weight, and seed yield tended to increase with delaying seeding up to 5 April and then to decrease with further delaying seeding. These results indicate that optimum seeding date of swordbean in unheated polyvinyl house would be early April. Although, the swordbean exhibited large increases in plant height, number of branches per plant, and stem diameter at the wider spacings, planting space could be decreased to the 60 cm plant-spacing and 30 cm row-spacing with no deleterious effect on yield.

• 한국농공학회지
• /
• 제15권3호
• /
• pp.3096-3106
• /
• 1973

As a link in the chain of antidrought measure, our attempt is made to obtain basic informations on the construction of an infiltration gallary which can be supplied with irrigation water by catching of underground water in small river beds, which is economical, permanent and efficient. The experiment was made, concerning the structure of catchment conduits, by constructing a model sand tank $1.5m{\times}5m{\times}1.5m$ in dimension made of reinforced concrete. Various kinds of measuring equipment were attached to the model tank which contains a set of catchment conduits, each of them was made 30cm in diameter and 60cm in length with the ratio of sectional area to total area of influx holes 10:1, 20:1, 30:1. The average size of influx holes was fixed from 0mm to 10mm, 20mm and 30mm in diameter respectively. Obtained results are as follow; (a) In view of the water catchment capacity, manufacturing cost and the antipressure strength of the catchment conduits, it is the best method to decide the total number of influx holes 20 per sq. meter of each tile surface, and the size of influx holes 20mm in diameter, when the conduits have diameter less than 1m. (b) The greatest factor of safety against external load is to arrange the influx holes in a zigzag manner on the tile surface. The most effective formula of arrangement is $S{\geqq}\sqrt{2gd}$ where: s : spacing of opening row. g : spacing of opening line. d : diameter of influs hole.

• 설비공학논문집
• /
• 제17권6호
• /
• pp.529-535
• /
• 2005

This study experimentally examines the air-side performance of spiral finned tube heat exchangers. The effects of fin spacing, fin height, and tube alignment were investigated. Reduction of fin spacing decreased the Colburn j factor. However, the effect of fin height on the Colburn j factor was negligible. An increase of tube row decreased the Nusselt number for both staggered and in-line tube alignments. However, the decrease of the Nusselt number for the in-line tube alignment was much more significant than that of the staggered tube alignment. The average Nusselt number of the staggered tube alignment was larger than that of the in-line tube alignment by $10\%$ when the Reynolds number ranged from 300 to 1700. An empirical correlation of the Nusselt number was developed by using geometric parameters of heat exchanger and correction factors. The correction factor considered the effects of tube alignment and number of tube rows on the heat transfer. The proposed correlation yielded a mean deviation of $4\%$ from the present data.