含水率變化가 穀物의 物理的 特性에 미치는 影響(I) -球形率, 重量, 體積-

오무영,Oh, Moo-Young 한국농공학회 1984 한국농공학회논문집 Vol.26 No.2

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.

시멘트 배합량(配合量)이 콘크리트의 소성수축(塑性收縮)에 미치는 영향(影響)

오무영 ( Oh Moo Young ),윤충섭 ( Yoon Choong Sup ) 한국농공학회 1976 韓國農工學會誌 : 전원과 자원 Vol.18 No.4

The objective of this study is to investigate the characteristics of the concrete mixture and the plastic shrinkage of concrete exposed to a rapid evaporation immediately after placement, and to measure the shringkage rate according to the cement-mixture. Drying of concrete was conducted under a controlled chamber in which the temperature was 36±2℃, the relative humidity 45±2%, and the wind velocity 4±1m/sec. All of the concrete mo1ds were made to have good workability as 6±0.5cm in slump. The results obtained are as follows; 1) The evaporation rate was 3.36kg/㎢, 2.98kg/㎢ and 2.91kg/㎢ respectively for each concretemixtures 365kg, 335kg and 317kg after 5 hour exposure, and the evaporation was measured at all 55∼57% after 2 hours and additional in 10% on after 5 hours exposure. 2) The weight of the concrete were was reduced to 3.0%, 2.6% and 2.4% respectively for each of them. 3) The shrinkage of concrete was 0.87 mm/m, 0.56mm/m and 0.31 mm/m after 5 hour exposure, and the shringkage of concrete was measured at 84%, 59% and 45% after 2 hours and it in 1∼5% after 5 hour exposure and then stopped. 4) A recommendation for good concrete is that the evaporation should be minimized during 2 hours after placement of concrete, if possible.

함수솔변화(含水率變化)가 의물(毅物)의 물리적(物理的) 특성(特性)에 미치는 영향(影響)(I) - 구형률(球形率),중량(重量),체적(體積) -

오무영 ( Oh Moo Young ) 한국농공학회 1984 韓國農工學會誌 : 전원과 자원 Vol.26 No.2

The Purpose of this study was to investigate the effect of the change in moisture content on some physical properties of grains, and some relations among 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 4.72×10^-5~3.58×10^-5kg for wheat, 3.60×10^-5~3.12×10^-5kg for barley, 2.80×10^-5~2.35×10^-5kg for rough rice, and 2.24×10^-5~1.82×10^-5kg 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 3.51×10^-8~2.76×10^-8m³for wheat, 2.84×10^-8~2.43×10^-8m³ for barley, 2.93×10^-8~1.97×10^-8m⁸m³ for rough rice, and 1.61×10^-8~1.29×10^-8m³for 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.

연약지반(軟弱地盤)에 대(對)한 사면안전(斜面安全)의 연구(硏究)

오무영 ( Oh Moo Young ) 한국농공학회 1967 韓國農工學會誌 : 전원과 자원 Vol.9 No.3

성형직후(成形直後) 건조환경(乾燥環境)이 시멘트 모르터의 강도(强度)에 미치는 영향(影響)

오무영 ( Oh Moo Young ),김준희 ( Kim Jun Hee ) 한국농공학회 1991 韓國農工學會誌 : 전원과 자원 Vol.33 No.2

This study was carried out to research the strength drop of concrete in dry environment. The mixing ratio of cement-fine aggregate was 1 : 1, 1 : 2, 1: 3 and 1 : 4. The curing was compared standard curing with dry curing immediately after casting. It is analysis of strength change by water-proof mixing. The curing age of cement mortar was 3days, 7days, l4days and 28days. The result obtained from this study are summarized as follows. 1. The compressive and bending strength change by increasing the curing age, dry curing mortar the increasing rate of strength was decreased than standard curing mortar. 2. The compressive and bending strength change in early curing, strength difference between standard curing mortar and dry curing mortar was gradually closed by increasing the W/C. 3. The dry curing mortar was decreased than standard curing mortar in decreasing rate of compressive and bending strength by increasing the W/C. 4. The compressive strength of water-proof mortar in early curing, liquid water-proof mortar was shown high strength in dry curing than standard curing. The powder and liquid water-proof mortar have a small effect in dry environment. The liquid water-proof mortar was high strength without relation change of curing age in dry environment than standard curing. 5. The compressive strength of liquid water-proof mortar in poverty mix, dry curing was shown high strength than standard curing. 6. The bending strength was increased than compressive strength by decreasing the volume of cement in early curing. The increasing rate of bending strength was decreased to compressive stength by increasing the curing age.

콘크리트의 Consistency 변화가 소성수축(塑性收縮)에 미치는 영향

오무영 ( Moo Young Oh ) 한국농공학회 1978 韓國農工學會誌 : 전원과 자원 Vol.20 No.1

The objective of this study is to investigate how the varieties of consistency of fresh concrete influence on the plastic shrinkage in dry condition. The test was conducted under the controlled chamber in which the temperature was kept at 25±2℃, the humidity 35±3%, and the wind velocity 4.0±0.5m/sec. The results obtained from the test are as follow. 1) The rate of evaporation was highest at 2-3 hour after casting, and decreased gradually. 2) The plastic shrinkage was increased as to the slump values. The shrinkage rate was very highest at 2-4 hour and hardly showed any changes after 6 hour. 3) The recommendation for good cloncrete is that slump value should be as low as possible in construction.

성형직후(成形直後) 증발작용(蒸發作用)을 받은 콘크리트의 강도(强度)에 대(對)한 연구(硏究)

오무영 ( Moo Young Oh ) 한국농공학회 1974 韓國農工學會誌 : 전원과 자원 Vol.16 No.4

The objective of this study was to investigate the characteristics of the evaporation rate, the plastic shrinkage and the compressive strength of concrete exposed to a rapid evaporation environment immediately after casting. Drying of concrete were conducted under a controlled chamber in which the temperature was mainfoimed at 30±1℃, the relative humidity 22±1 percent, and the wind velocity 7±1 m/sec. The compressive strength of concrete was tested after 28 days of standard curing. The results obtained are as follows: 1. The evaporation rate was the highest at the very beginning, was decreased as the drying progresses, and was kept almost constant after 6 hours. 2. The shrinkage of concrete was changed in three different rates for the concrete mixture having its slump vallue between 3.0cm and 7.5cm. 3. The plastic shrinkage was ended within 5 or 6 hours after casting, regardless of the water cement ratio. 4. The shrinkage was increased within the limit of slump values between 3.0cm and 7.5cm as the water-cement ratio was increased. 5. The evaporation was kept on even after the plastic shrinkage was ended. 6. Within the limit of good workability (slump value between 4.5cm and 7.5cm), the compressive strength of concrete was increased when the shrinkage rate was slow but it was decreased when the rate was rapid 7. From the result of this study it is recommended that (1) the water-cement ratio should be less as long as the workability of concrete is allowable; (2) the evaporation should be prevented at least for 4 hours after casting concrete.

철근(鐵筋)콘크리트 단순(單純)스라브교(橋)의 설계(設計)모우멘트의 비교연구(比較硏究)

오무영 ( Moo Young Oh ) 한국농공학회 1972 韓國農工學會誌 : 전원과 자원 Vol.14 No.2

Agricultural road bridges are mostly constructed with simple slab structure We can’t get any standard results in designing of them, while we don’t have authentic specifications yet. Up to the present, Japanese and AASHO codes bave been used, but they dide’nt bring perfect detas in design. In this repart, I am going to study the distrebution and maxinam moment of truck load on the road surface to put in order some specifications of the simple slab bridge. Truck load paesents D hard, which is effect on the simple slab bridge bridge, and lane load. D load is provided into whl loads which is distributer on the effecient width E as a concentrated load to work on one point. Max load aming into one meter of slab is E. Being the main reinforce ment paralled to traffic, the efficicient width E is as follow; E=1.2+0.06S In this formular, E shonld be equal or smaller than than 2.1m, ands in the span for moment. Max. moment M=1/E-PS/4 In Japanese specification. Max. moment of the simple slab bridge is H=1.8s+0.5(t·m),for the span is 3.0~10.0 meter, as we compare with another specifications Max. moment has variety to increase to span length of slob showed in fig I.

함수율변화(含水率變化)가 곡물(穀物)의 물리적특성(物理的特性)에 미치는 영향(影響) (II) - 진밀도(眞密度), 충적밀도(充積密度), 압축도(壓縮度) -

오무영 ( Oh Moo Young ) 한국농공학회 1985 韓國農工學會誌 : 전원과 자원 Vol.27 No.3

The purpose of this study was to investigate the effect of the change in moisture content on some physical properties of grains, and some relations among the properties. Materials included were 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. True density, bulk density and compressibility were included as the physical properties of the grains. The results obtained are summarized as follows; 1. With the increase in moisture content, the true density was linearly decreased for brown rice, barley and wheat, but was linearly increased for rough rice. At a specified moisture content of 14 percent, the value was in the range of 1407~1389kg/㎥ for brown rice, 1354~1295kg/㎥ for wheat, 1286~1259kg/㎥ for barley, and 1200~1142kg/㎥ for rough rice, respectively. 2. With the increase in moisture content, the bulk density of grains was linearly increased for rough rice, linearly decreased for brown rice, and hyperbolically related for barley and wheat. At a specified moisture content of 14 percent, range of 606~567kg/㎥ for rough rice, 779~751kg/㎥ for brown rice. The Maximum value for barley was in the range of 655~636kg/㎥ at the moisture content of 14 percent and 814~740kg/㎥ for wheat at 12 percent. 3. With the increase in moisture content, the tap bulk density was linearly incresed for rough rice, linearly decreased for brown rice, and hyperbolically related for barley and wheat. The value at a specified moisture content and the maximum values were increased by tapping. 4. The compressibility of grains was decreased with the increase of moisture content for rough rice and brown rice, it was increased from the moisture content of 14 percent for barley, and was shown minimum value at moisture content range of 12~16 percent for wheat.

지형공간정보체계를 적용한 농장의 적지분석에 관한 연구

이신호(RHEE Shin-Ho),오무영(OH Moo-Young),최진용(CHOI Jin-Young),김한중(KIM Han-Joong) 대한공간정보학회 1995 대한공간정보학회지 Vol.3 No.2