• Magazine of the Korean Society of Agricultural Engineers
• /
• v.16 no.1
• /
• pp.3225-3262
• /
• 1974

The purposes of this thesis are to clarify experimentally the variation of ground water temperature in tube wells during the irrigation period of paddy rice, and the effect of ground water irrigation on the growth, grain yield and yield components of the rice plant, and, furthermore, when and why the plant is most liable to be damaged by ground water, and also to find out the effective ground water irrigation methods. The results obtained in this experiment are as follows; 1. The temperature of ground water in tube wells varies according to the location, year, and the depth of the well. The average temperatures of ground water in a tubewells, 6.3m, 8.0m deep are $14.5^{\circ}C$ and $13.1^{\circ}C$, respercively, during the irrigation period of paddy rice (From the middle of June to the end of September). In the former the temperature rises continuously from $12.3^{\circ}C$ to 16.4$^{\circ}C$ and in the latter from $12.4^{\circ}C$ to $13.8^{\circ}C$ during the same period. These temperatures are approximately the same value as the estimated temperatures. The temperature difference between the ground water and the surface water is approximately $11^{\circ}C$. 2. The results obtained from the analysis of the water quality of the "Seoho" reservoir and that of water from the tube well show that the pH values of the ground water and the surface water are 6.35 and 6.00, respectively, and inorganic components such as N, PO4, Na, Cl, SiO2 and Ca are contained more in the ground water than in the surface water while K, SO4, Fe and Mg are contained less in the ground water. 3. The response of growth, yield and yield components of paddy rice to ground water irrigation are as follows; (l) Using ground water irrigation during the watered rice nursery period(seeding date: 30 April, 1970), the chracteristics of a young rice plant, such as plant height, number of leaves, and number of tillers are inferior to those of young rice plants irrigated with surface water during the same period. (2) In cases where ground water and surface water are supplied separately by the gravity flow method, it is found that ground water irrigation to the rice plant delays the stage at which there is a maximum increase in the number of tillers by 6 days. (3) At the tillering stage of rice plant just after transplanting, the effect of ground water irrigation on the increase in the number of tillers is better, compared with the method of supplying surface water throughout the whole irrigation period. Conversely, the number of tillers is decreased by ground water irrigation at the reproductive stage. Plant height is extremely restrained by ground water irrigation. (4) Heading date is clearly delayed by the ground water irrigation when it is practised during the growth stages or at the reproductive stage only. (5) The heading date of rice plants is slightly delayed by irrigation with the gravity flow method as compared with the standing water method. (6) The response of yield and of yield components of rice to ground water irrigation are as follows: \circled1 When ground water irrigation is practised during the growth stages and the reproductive stage, the culm length of the rice plant is reduced by 11 percent and 8 percent, respectively, when compared with the surface water irrigation used throughout all the growth stages. \circled2 Panicle length is found to be the longest on the test plot in which ground water irrigation is practised at the tillering stage. A similar tendency as that seen in the culm length is observed on other test plots. \circled3 The number of panicles is found to be the least on the plot in which ground water irrigation is practised by the gravity flow method throughout all the growth stages of the rice plant. No significant difference is found between the other plots. \circled4 The number of spikelets per panicle at the various stages of rice growth at which_ surface or ground water is supplied by gravity flow method are as follows; surface water at all growth stages‥‥‥‥‥ 98.5. Ground water at all growth stages‥‥‥‥‥‥62.2 Ground water at the tillering stage‥‥‥‥‥ 82.6. Ground water at the reproductive stage ‥‥‥‥‥ 74.1. \circled5 Ripening percentage is about 70 percent on the test plot in which ground water irrigation is practised during all the growth stages and at the tillering stage only. However, when ground water irrigation is practised, at the reproductive stage, the ripening percentage is reduced to 50 percent. This means that 20 percent reduction in the ripening percentage by using ground water irrigation at the reproductive stage. \circled6 The weight of 1,000 kernels is found to show a similar tendency as in the case of ripening percentage i. e. the ground water irrigation during all the growth stages and at the reproductive stage results in a decreased weight of the 1,000 kernels. \circled7 The yield of brown rice from the various treatments are as follows; Gravity flow; Surface water at all growth stages‥‥‥‥‥‥514kg/10a. Ground water at all growth stages‥‥‥‥‥‥428kg/10a. Ground water at the reproductive stage‥‥‥‥‥‥430kg/10a. Standing water; Surface water at all growh stages‥‥‥‥‥‥556kg/10a. Ground water at all growth stages‥‥‥‥‥‥441kg/10a. Ground water at the reproductive stage‥‥‥‥‥‥450kg/10a. The above figures show that ground water irrigation by the gravity flow and by the standing water method during all the growth stages resulted in an 18 percent and a 21 percent decrease in the yield of brown rice, respectively, when compared with surface water irrigation. Also ground water irrigation by gravity flow and by standing water resulted in respective decreases in yield of 16 percent and 19 percent, compared with the surface irrigation method. 4. Results obtained from the experiments on the improvement of ground water irrigation efficiency to paddy rice are as follows; (1) When the standing water irrigation with surface water is practised, the daily average water temperature in a paddy field is 25.2$^{\circ}C$, but, when the gravity flow method is practised with the same irrigation water, the daily average water temperature is 24.5$^{\circ}C$. This means that the former is 0.7$^{\circ}C$ higher than the latter. On the other hand, when ground water is used, the daily water temperatures in a paddy field are respectively 21.$0^{\circ}C$ and 19.3$^{\circ}C$ by practising standing water and the gravity flow method. It can be seen that the former is approximately 1.$0^{\circ}C$ higher than the latter. (2) When the non-water-logged cultivation is practised, the yield of brown rice is 516.3kg/10a, while the yield of brown rice from ground water irrigation plot throughout the whole irrigation period and surface water irrigation plot are 446.3kg/10a and 556.4kg/10a, respectivelely. This means that there is no significant difference in yields between surface water irrigation practice and non-water-logged cultivation, and also means that non-water-logged cultivation results in a 12.6 percent increase in yield compared with the yield from the ground water irrigation plot. (3) The black and white coloring on the inside surface of the water warming ponds has no substantial effect on the temperature of the water. The average daily water temperatures of the various water warming ponds, having different depths, are expressed as Y=aX+b, while the daily average water temperatures at various depths in a water warming pond are expressed as Y=a(b)x (where Y: the daily average water temperature, a,b: constants depending on the type of water warming pond, X; water depth). As the depth of water warning pond is increased, the diurnal difference of the highest and the lowest water temperature is decreased, and also, the time at which the highest water temperature occurs, is delayed. (4) The degree of warming by using a polyethylene tube, 100m in length and 10cm in diameter, is 4~9$^{\circ}C$. Heat exchange rate of a polyethylene tube is 1.5 times higher than that or a water warming channel. The following equation expresses the water warming mechanism of a polyethylene tube where distance from the tube inlet, time in day and several climatic factors are given: {{{{ theta omega (dwt)= { a}_{0 } (1-e- { x} over { PHI v })+ { 2} atop { SUM from { { n}=1} { { a}_{n } } over { SQRT { 1+ {( n omega PHI) }^{2 } } } } LEFT { sin(n omega t+ { b}_{n }+ { tan}^{-1 }n omega PHI )-e- { x} over { PHI v }sin(n omega LEFT ( t- { x} over {v } RIGHT ) + { b}_{n }+ { tan}^{-1 }n omega PHI ) RIGHT } +e- { x} over { PHI v } theta i}}}}{{{{ { theta }_{$\infty$ }(t)= { { alpha theta }_{a }+ { theta }_{ w'} +(S- { B}_{s } ) { U}_{w } } over { beta } , PHI = { { cpDU}_{ omega } } over {4 beta } }}}} where $\theta$$\omega$; discharged water temperature($^{\circ}C$) $\theta$a; air temperature ($^{\circ}C$) $\theta$$\omega$';ponded water temperature($^{\circ}C$) s ; net solar radiation(ly/min) t ; time(tadian) x; tube length(cm) D; diameter(cm) ao,an,bn;constants determined from $\theta$$\omega$(t) varitation. cp; heat capacity of water(cal/$^{\circ}C$ ㎥) U,Ua; overall heat transfer coefficient(cal/$^{\circ}C$ $\textrm{cm}^2$ min-1) $\omega$;1 velocity of water in a polyethylene tube(cm/min) Bs ; heat exchange rate between water and soil(ly/min)

• Proceedings of the Korean Vacuum Society Conference
• /
• 2016.02a
• /
• pp.159-159
• /
• 2016

Vertically-aligned carbon nanotubes (VCNT) have attracted much attention due to their unique structural, mechanical and electronic properties, and possess many advantages for a wide range of multifunctional applications such as field emission displays, heat dissipation and potential energy conversion devices. Surface modification of the VCNT plays a fundamental role to meet specific demands for the applications and control their surface property. Recent studies have been focused on the improvement of the electron emission property and the structural modification of CNTs to enable the mass fabrication, since the VCNT considered as an ideal candidate for various field emission applications such as lamps and flat panel display devices, X-ray tubes, vacuum gauges, and microwave amplifiers. Here, we investigate the effect of surface morphology of the VCNT by water vapor exposure and coating materials on field emission property. VCNT with various height were prepared by thermal chemical vapor deposition: short-length around $200{\mu}m$, medium-length around $500{\mu}m$, and long-length around 1 mm. The surface morphology is modified by water vapor exposure by adjusting exposure time and temperature with ranges from 2 to 10 min and from 60 to 120oC, respectively. Thin films of SiO2 and W are coated on the structure-modified VCNT to confirm the effect of coated materials on field emission properties. As a result, the surface morphology of VCNT dramatically changes with increasing temperature and exposure time. Especially, the shorter VCNT change their surface morphology most rapidly. The difference of field emission property depending on the coating materials is discussed from the point of work function and field concentration factor based on Fowler-Nordheim tunneling.

• The Korea Journal of Herbology
• /
• v.30 no.3
• /
• pp.35-40
• /
• 2015

Objectives : Zizyphus jujube (ZJ) has been used as a traditional medicine for various diseases. However, the inhibitory effect of ZJ on intestinal inflammation has not been fully understood, yet. The aim of this study is to investigate anti-colitis activity of ZJ in dextran sulfate sodium (DSS)-induced colitis mouse model. Methods : To investigate the protective effects of ZJ,the colitis mice were induced by drinking water containing 5% DSS for 7 days. Mice were randomized into groups receiving ZJ (500 mg/kg), sulfasalazine (SFZ) (150 mg/kg) as a positive control, or water as a negative control. We assayed the effects of ZJ on DSS-induced the clinical signs, measuring weight loss, colon length and disease activity index (DAI). Additionally, to find a possible explanation for the anti-inflammatory effects of ZJ, we evaluated the effects of ZJ on the production of prostaglandin $E_2$ ($PGE_2$) and expression of cyclooxygenase (COX)-2 in colitis tissue. Results : The results showed that mice treated with DSS showed considerable clinical signs, including weight loss, and reduced colon length. However, administration of ZJ significantly reduced the weight loss, shortens colon length, and improved DAI as clinical symptoms. Moreover, ZJ inhibited the $PGE_2$ production and COX-2 expression levels in DSS-treated colon tissues. Conclusions : Collectively, the findings of this study provide us with novel insights into the pharmacological actions of ZJ as a potential molecule for use in the treatment of intestinal inflammation including ulcerative colitis.

• Water for future
• /
• v.29 no.3
• /
• pp.143-152
• /
• 1996

The hydraulics of flow within the covered reach of urban streams is very complicated due to the accumulation and interference effect of eddies around the multiple piers supporting the covering slab. An extensive experimental study is done to quantitatively estimate the backwater rise effect caused by various arrays of multiple piers. The factors governing the backwater rise are found out to be the contraction ratio due to the piers, Froude number of the flow, longitudinal pier spacing, and the length of the covered reach. For a single section of lateral pier arrays the effect of contraction ratio and Froude number on the backwater rise is analyzed and a multiple regression equation is derived. The effect of multiple piers, arrayed in both lateral and longitudinal directions, on the backwater rise is analyzed in terms of the contraction ratio, Froude number,longitudinal pier spacing and the total length of the covered reach. A multiple regression equation for the backwater rise estimation is proposed based on the experimental data collected in the present study.

• The Korea Journal of Herbology
• /
• v.29 no.4
• /
• pp.29-34
• /
• 2014

Objectives : Ulcerative colitis (UC) is an inflammatory bowel disease, which is one of chronic gastrointestinal disorders. Orostachys japonicus (OJ) has been used as a traditional medicine for various diseases including gastric cancer, gastric ulcers and intoxication. However, the regulatory effect of OJ on intestinal inflammation has not been fully understood, yet. The aim of this study was to investigate the effect of OJ on dextran sulfate sodium (DSS)-induced colitis in mice. Methods : To ascertain the pharmacological effects of OJ, the colitis mice were induced by drinking water containing 5% DSS for 7 days. Mice were randomized into groups receiving OJ (100 mg/kg), sulfasalazine (150 mg/kg) as a positive control, or water as a negative control. We evaluated the effects of OJ on DSS-induced the clinical signs, measuring weight loss and colon length. In addition, the inhibitory effect of OJ on the tumor necrosis factor-${\alpha}$ (TNF-${\alpha}$) level was determined by enzyme-linked immunosorbent assay in colitis tissue. Results : The results indicated that mice treated with DSS showed remarkable clinical signs, including weight loss, and reduced colon length. However, treatment with OJ significantly improved the weight loss and DAI as clinical symptoms. Moreover, OJ reduced the TNF-${\alpha}$ levels in DSS-treated colon tissues. Conclusions : Collectively, the findings of this study provide us with novel insights into the pharmacological actions of OJ as a potential medicine for use in the treatment of ulcerative colitis.

• The Journal of Pediatrics of Korean Medicine
• /
• v.20 no.2
• /
• pp.19-34
• /
• 2006

Objective : The purpose of this study is to find out the effect of Jowonsangamibang(JWS) on the growth of rats. Methods : First of all, we divided male Sprague-Dawley rats into 4 groups(J1, J2, J3 and sham group). Then J1, J2 and J3 groups were administered with JWS water extracts(JWSE) once a day at a dosage 250, 500, 1,000mg/kg respectively for 3 weeks. The sham group was administered with normal saline in the same manner. And we measured body weight, amount of body weight increased, length of femur, serum GH, serum IGF-I, serum TSH and serum testosterone after each week. Results : There were no significant changes of body weight, the level of GH, TSH, and testosterone in J1, J2 and J3 groups. The change of body weight gained was increased significantly in the J3 group compared with the sham group after 1, 2 and 3 weeks. The length of the femur was increased significantly in the J2 group after 1 week and in the J3 group after 3 weeks compared with the sham group. The level of IGF-I in the serum was increased significantly in J1, J3 after 1 week compared with the sham group. Conclusion : According to the results above, JWS increased body weight, length of femur, serum GH, serum IGF-1 compared with the sham group. This study shows that JWS has an effect on promoting the growth of rats, thus it's expected to treat of growth delay in children.

• Journal of Korean Society of Water and Wastewater
• /
• v.29 no.5
• /
• pp.559-564
• /
• 2015

Distribution basins are used widely in the water treatment process. Uniform distribution at the distribution basin is an important because it affect precipitation efficiency of sedimentation basin. Generally distribution basin has a free surface water and is consisted of a weir. Study result, when inflow of distribution basin is less, amount of overflow is much at the nearest weir from the inlet. But when inflow is much, amount of overflow is much at the far weir from the inlet. The difference of distribution amount at the pipe is affected by the curvature and length of the pipe. The magnitude of the effect is determined by the relative energy loss and the flow state of the distribution basin. Optimization of the response surface method for minimizing an amount of deviation of the distribution is a very useful technique to determine the optimal ratio of the valve opening.

• Proceedings of the Korean Society of Agricultural Engineers Conference
• /
• 1998.10a
• /
• pp.382-387
• /
• 1998

Triaxial compression tests were run to study on the undrained strength characteristics of fiber mixed kaolin clay(Hadong). The influence of various test parameters such as amount and aspect ratio(ratio of length to diameter) of fiber, confining stress was also investigated. Test results showed that the increase in aspect ratio was increased in deviator stress at failure, but no effect on pore water pressure at failure. Deviator stress at failure was also increased at 0.5％ mixing ratio(weight fraction of fiber to that of soil solid) of fiber but it was, thereafter, decreased and wits reached to constant after 2％ mixing ratio. On the contrary, Pore water pressure at failure was increased as mixing ratio of fiber was greater than 1%. Deviator stress and pore water pressure of both clay and fiber mixed clay(FMC) at failure were increased as confining stress was increased. Deviator stress of FMC at failure was about 10％ larger than that of clay, but pore water pressure of FMC at failure was almost similar to that of clay.

• Journal of the Korea Safety Management & Science
• /
• v.25 no.2
• /
• pp.129-138
• /
• 2023

This study attempted to analyze the comparative advantage in terms of disaster safety costs in verifying the effectiveness and economic feasibility of the high-performance water-bulwark system in the pole tunnel, which was recently promoted as a part of the acceleration of vehicles. The tunnel to be analyzed was divided into a short tunnel(Anyang, Cheonggye) and a long tunnel(Suraksan, Sapaesan). As a result, it was analyzed that 25% of the improvement effect would occur if one lane was secured by applying the Water-Bulwark System. It was analyzed that this is because the time value cost, which accounts for a large proportion of the traffic congestion cost of short tunnels and pole tunnels, differs depending on the congestion time and traffic volume, not the length of the tunnel.

• Journal of the Korean GEO-environmental Society
• /
• v.23 no.2
• /
• pp.25-36
• /
• 2022

In this study, seepage control effect of relief well was evaluated quantitatively on embankment of small fill dam and levee. Seepage analysis of dam and levee were carried out according to the permeability of fill material and foundation and to analyze behaviour characteristics of seepage. The up-lift pressure at toe of embankment was analyzed which is generated by seepage according to relief well installation condition. The relief well could reduce pore water pressure which is to cause piping or up-lift pressure at foundation ground of embankment and it does not be influenced on geometric condition such as dam height and slope incline. In case of relative low permeable ground, the pore water pressure reduction effect of relief well was decreased compare with high permeable ground but it shows pore water pressure reduction effect compare with no relief well condition. The reduction effect of relief well shows relative gap according to diameter and penetration length of relief well and the installation length of relief well is the most effective factor for seepage control.