貫入을 받는 表土의 리올러지 特性 : 貫入抵抗應力弛綬 Penetration Stresss Relaxation

羅又禎 慶尙大學校 1991 論文集 Vol.30 No.2

This study was carried out to figure out the effect of the moisture content and the penetration rate on the penetratin stress relaxation behavior of the surface soil of a loamy sand under laboratory conditions. The following results were obtained from the study. 1. The penetration stress relaxation characteristics of the surface of a loamy sand can be described by a generalized Maxwell model consisting of the Maxwell elements. 2. At the moisture content of 20% and penetration speed of 50 mm/min, for all the probes, residual stresses were the greatest, being about 65∼68% of initial stress. And relaxation intensity of the second element was the greatest at the same condition. 3. With the increase of penetration speed, the rate of the decrease of residual stress was increased and relaxation intensity was increased, too.

고점성 바이오유의 미립화를 위한 초음파의 적용

주은선,나우정,김종천 慶尙大學校生産技術硏究所 1996 生産技術硏究所論文集 Vol.12 No.-

An experiment was conducted to figure out the atomization characteristics of rice-bran oil which is a highly viscous liquid by applying ultrasonic energy to improve the atomization of spray droplets. A spray simulator, an ultrasonic system, and six different nozzles(three kinds of single hole-type nozzles and three kinds of pintle-type nozzles) were made. To investigate the effects of ultrasonic energy on the atomization of a highly viscous liquid, a phase doppler particle analyzer was used for measurement and calculation of spray droplets data. Nozzle opening pressures chosen were of 5 levels, i. e., 10 MPa, 13 MPa, 16 MPa, 20 MPa, and 24 MPa. It was observed that the application of ultrasonic energy into the highly viscous rice-bran oil was effective for the atomization improvement of the liquid fuel. With the increase of nozzle opening pressures and pin-edge angles, and with the decrease of the hole diameters, the atomization of spray droplets was improved, which conforms to general theoretical characteristics.

굴절률이 Dual-Beam LDV의 信號特性에 미치는 影響

朱恩選,羅又禎 慶尙大學校 1986 論文集 Vol.25 No.2

The effects of refractive indices on the visibility which is an important characteristic in a Dual-Beam LDV are investigated. There are two methods for experiment; One is in the case of the variety of refractive indices of scatterers, and the other in the case of the variety of refractive indices of media. In this study, the above second method was selected in order to find that the refractive index is an important parameter on the visibility. A resistance wire with 30㎛ width and a Pt wire with 50㎛ width were applied as scatterers. Five media, ie., H2O(n=1.332), Chloroform (n=1.444), DMSO (n=1.476), Benzyl alcohol (n=1.538) and Carbondisulfide (n=1.628), were used as surrounding media. In the result, it is found that the refractive index of scatter is a parameter of the visibility.

??형 超音波 噴霧器에 依한 세탄液滴의 微粒化 特性

李智弘,鄭鎭度,羅又禎 慶尙大學校 1991 論文集 Vol.30 No.2

This study was performed to figure out the atomization characteristics of free-falling oetane droplets from a π-type ultrasonic vibrator dircted downwards. Droplets were collected by the magnesium oxide immersion method. The diameter and distribution of droplets were measured and analyzed. The results are summarized as following : 1. The shape of free-falling oetane droplets in space from the π-type ultrasonic vibrator was fully developed promixed spray column, showing almost the same diameter as the outer diameter of the horn through its whold length. 2. The mean of the Sauter mean diameter of the collected cetane droplets was 52.8㎛, and, its maximum and minimum droplet diameters were approximately 95 ㎛ and 15 ㎛, respectively. 3. The distribution types of droplet size were right-skewed Gaussian distribution curve in all cases with small variace. The Sauter mean diameters ranged from 48 ㎛ to 59 ㎛.

3個의 耕耘날을 利用한 平衡振動式 耕耘裝置(Ⅲ) : 垂直加振時의 振動特性 Characteristics of Vibration Induced by Vertical Oscillation

金容煥,金成泰,羅又禎 慶尙大學校 1984 論文集 Vol.23 No.2

This is the third of series of reports on the study on a balanced type oscillating tillage implement using triple blades system. Previous reports of this study, the characteristics of vibration and power requirement induced by horizontal oscillation were presented. In this paper, the vertical and horizontal vibration tendency due to the various oscillating frequencies, amplitudes, lift angles and travel speeds appeared by vertical oscillation were investigated. Obtained results are as follows: 1. Oscillating accelerations on the vertical and horizontal direction were decreased by increased travel speed, and were increased by increased oscillating frequency and amplitude. 2. The lowest oscillating acceleration in each direction was shown at the condition of travel speed 0.2m/s, oscillating frequency 7.5Hz, amplitude 2mm and lift angle was 30℃. But there must be considered at the same time the side of view for total power requirement, tillage effect, and reduction effect of oscillating acceleration to determine the optimum condition of the instrument. 3. Triple blades tillage implement, using these studies, was shown a great potential capacity for the side of reduction effect of oscillating acceleration, compare with many other non-balanced oscillating tillage systems.

溫室保溫커튼의 材料特性에 따른 保溫效果分析

金榮福,金容換,李昇揆,金成泰,羅又禎,閔永鳳,朴重春,崔東烈 慶尙大學校 1991 論文集 Vol.30 No.2

The effects of the material properties of thermal curtains upon reduction of the greenhouse heat loss were studied. A theoretical analysis procedure with equations and computer programs was developed to estimate them by using energy balance principles. Curtain effectiveness for every three kinds pf value level of the material properties were studied and compared. The results of this study would be useful for the developent and management of greenhouse thermal curtains.

土壤硬度測定器具 開發에 關한 硏究

金容煥,河浩成,李昇揆,金成泰,羅又禎,閔泳鳳 慶尙大學校 1980 論文集 Vol.19 No.1

An instrument for measuring cone penetration using the strain gage system was devised. The soil hardness of given soils under different conditions can be measured and compared by using this instrument. The soil hardness is a very useful index for making decisions in various aspects of the field and laboratory use; the workability of the agricultural machinery on the given field, and the uniformity of soil hardness of the stuffed soil in the soil bin which is tilled repeatedly. The performance of this newly devised cone penetrometer was compared with the conventional one through the field test. The summarized results are as follows; 1. In case of KM-1 type cone penetrometer, the newly devised one, the relation between the cone index and the strain indicated are as follows, Ci=0.026642ε₁-0.4173 when base area is 3.23㎠ Ci=0.013342ε₂ when base area is 6.45㎠ 2. The KM-1 type cone penetrometer is more convenient than conventional one in view of its accuracy and its adaptability of the self recording system. 3. Cone index increases gradually as penetrating depth into the soil is increased. Its maximum value appeared at the depth of about 20cm and then the cone index decreases until the cone reaches the depth of 40cm. It is assumed that such increase of cone index is caused by the existence of plow pan in paddy fields. 4. When cone penetrometers are manually penetrated into the soil deeper than 20cm from ground surface, its found to be difficult to carry out measuring operations due to high soil resistance to penetration. So, in order to use cone penetrometers below the depth more than 20cm, some equipment is necessary to maintain uniform penetrating speed of the cone. 5. Under the same soil conditions, the relation between Cik and Cic, cone indexes derived KM-1 type from conventional cone penetrometers respectively, was as follow;??

Study on the Tractive Characteristics of the Seed Furrow Opener for No-till Planter

Woo-Jung La(羅又禎) 충남대학교 농업과학연구소 1978 農業技術硏究報告 Vol.5 No.2

" EVALUATION OF THE PENETROMETER TEST FOR ASSESSING THE SOIL SURFACE STRENGTH "

Woo Jung La 경상대학교 경남문화연구소 1986 慶南文化硏究 Vol.9 No.1

Study on the Tractive Characteristics of the Seed Furrow Opener for No-till Planter

La, Woo-Jung 충남대학교 농업과학연구소 1978 農業技術硏究報告 Vol.5 No.2

動力耕耘機用 豆類의 無耕耘 播種機에 附着하여 使用하는 溝切器中에서 所要牽引力이 작고 溝切作業 精度가 良好한 溝切器의 開發을 爲한 基礎資料를 얻기 爲하여 驅動式 土槽에 人工土壤을 채우고 圓板型 및 호우型 溝切器의 所要牽引力과 이에 影響을 미치는 因子들과의 關係를 究明코자 室內模型 實驗을 實施하여 다음과 같은 結果를 얻었다. 圓板型 溝切器에 對하여 直徑別로 組立角을 8°와 16°, 耕深을 3cm와 6cm로 變化시키면서 2.75cm/sec의 速度로 牽引力을 測定한 結果 圓板의 直徑이 約 28cm인 境遇에 牽引力이 最少로 나타났고, 直徑이 이보다 크거나 작은때는 牽引力은 增加하는 傾向을 나타냈으며 比抵抗도 大體로 비슷한 傾向이었으나 圓板의 直徑이 約 30cm일 때 最少로 나타났다. 種子播種의 深度調節을 目的으로 作溝深(3cm 및 6cm)과 牽引力과의 關係를 調査하였던 바, 耕深과 牽引力과의 關係는 거의 直線的인 變化를 나타냈으며 牽引力에 影響을 미치는 因子中에서 耕深의 影響이 가장 컸음을 알 수 있었다. 一般的으로 組立角 및 走行速度에 別 影響없이 耕深 3cm 및 6cm 共히 牽引力은 直徑 約 28cm에서, 比抵抗은 約 30cm에서 最少의 값을 나타내었다. 播種機의 作業性能과 關係가 깊은 走行速度 및 播巾의 調節을 目的으로 圓板의 組立角과 走行速度가 牽引力에 미치는 影響을 調査했던 바, 組立角과 走行速度가 增加함에 따라 모두 牽引力이 增加하는 傾向을 나타내었으나 牽引力에 미치는 影響은 走行速度가 더욱 크게 나타났다. 圓板型 溝切器가 호우型 溝切器를 比較하기 爲하여 쐐기角이 16°이고 리프트角이 20°인 호우型 溝切器와 條件이 비슷한 組立角 16°의 圓板型 溝切器의 牽引特性을 比較한 結果 直徑 30cm인 圓板型의 境遇는 比抵抗이 0.35∼0.5㎏/cm^2인데 比해 호우型의 境遇는 0.71∼1.02kg/cm^2로 나타나 호우型의 牽引比抵抗이 平均 2倍程度 크게 나타났고 竹溝狀態도 圓板型의 境遇보다 不良하였다. This study was carried out to obtain basic data for the type selection of furrow openers for the notillage soybean planter trailed by the two-wheel tractor from the standpoint of minimum draft and good performance of furrowing. For this study, two models of furrow opener, hoe and disc type, were tested on the artificial soil stuffed in the moving soil bin. The results obtained were as follows. In the case of disc furrow opener, the drafts were measured according to various diameters of discs under the condition of disc angle 8° and 16°, working depth 3cm and 6cm, working speed 2.75cm/sec. Minimum draft appeared when the diameter of disc was about 28cm and the drafts increased as the diameter of discs became larger or smaller than this diameter. Specific draft showed almost same tendencies as above but showed the minimum when the diameter was about 30cm. For the purpose of controlling the seeding depth, the relationships between draft and working depths, 3cm and 6cm, were tested, The variations of draft concerning the various working depths showed linear changes and were affected in higher degree by depths than other factors. There were general tendencies at both working depths, 3cm and 6cm, that total draft showed the minimum with the disc diameter of about 28cm and specific draft showed it with the disc diameter of about 30cm regardless of disc angle and working speed. For the purpose of controlling the working width and speed, the relationships among drafts, disc angle and working speed were investigated and there were general tendencies that the draft increased as the angle and speed were increased and the draft was affected more by speed than by angle. To compare the hoe-type with disc-type opener, the specific drafts of hoe openers were compared with those of disc opener of 16° angle and 30cm diameter. The specific draft of disc-type opener with the diameter of 30cm was 0.35∼0.5 kg/㎠ in while 0.71∼1.02 kg/㎠ in the case of hoe type with the lift angle of 20° which is 2 times as much as that of disc type in average value. And the furrows opened by disc openers were cleaner than those opened by hoe openers.