• Journal of The Korean Society of Agricultural Engineers
• /
• v.47 no.7
• /
• pp.49-56
• /
• 2005

Contamination in the drainage channels and creeks with pesticides used in agriculture is of a major concern in many countries. In this study the stream pesticide model RIVWQ (chemical transport model for riverine environments) was assessed for its applicability in simulating pesticide fate in drainage channels. The model was successfully calibrated against field data collected on flows and pesticide concentrations for a drainage channel from a small catchment in the Murrumbidgee Irrigation Area of southwestern New South Wales. The effects of different pesticide loading scenarios from farm fields on channel water quality were analysed by the calibrated model. The model simulated the flow rates and the pesticide concentrations in the drainage channel well. The results of the model simulation suggest that the RIVWQ model can be effectively used for predicting pesticide fate in the drainage channels and exposure assessment of pesticide in the agricultural environment.

• Journal of Korea Technical Association of The Pulp and Paper Industry
• /
• v.33 no.4
• /
• pp.7-14
• /
• 2001

Recycled fibers usually give slow drainage in the paper forming process, which limits the application of more refining to the recycled fibers for improving paper strength and formation. To use recycled fibers more effectively, especially OCC, developing very efficient handling technique of short fibers and fines is inevitable. We tried to make hard flocs of fractionated short fibers and fines, which were the main cause of slow drainage, by adding excessive amount of retention aid selectively on them. This technique was proved to increase drainage considerably, but to decrease strength properties, compared to the conventional technique of adding the same amount of polymers to the whole furnish in the lab test. The bonding capability of short fibers and fines in Korean OCC was very poor. Various chemical treatment on the short fibers and fines of the Korean OCC did not improve their bonding and optical properties. One of the reasons of no improvement in their properties was their high amount of ashes.

• Korean Journal of Agricultural Science
• /
• v.37 no.1
• /
• pp.97-104
• /
• 2010

In this study, a laboratory model test on utilization of recycled aggregates and crushed stone as vertical drains to use alternative material of sand in soft ground is performed. The vertical and horizontal coefficient of permeability of the recycled aggregates and crushed stone showed largely 1.2~4.0 times and 3.0~3.3 times greater than sand, respectively. Therefore, it showed enough to be an alternative material to the sand which had been being used as the vertical and horizontal drainage material before. The variations of pore water pressure with time showed constantly regardless of the load in all vertical drainage materials. When water level drops suddenly, the pore water pressure of the recycled aggregate and crushed aggregate is reduced to nearly zero. Therefore, it was applicable to the field because discharge capacity was similarity to that of sand. The settlement in crushed aggregates and recycled aggregate decreases gradually with the load increase. When water level drops suddenly, earth pressure in all drains materials was evaluated the equivalent drainage capacity similarity to sand because it show approaching the nearly zero.

• Journal of Korea Technical Association of The Pulp and Paper Industry
• /
• v.46 no.5
• /
• pp.61-68
• /
• 2014

The energy efficiency of papermaking process becomes more significant because of various new regulation of the energy consumption and the green house gas emission. In this study, the effects of wood powder addition on the drainage and the drying efficiency of the OCC based paper products, linerboard, were deeply investigated for improving energy efficiency. The fractionation of wood powder depending on the size were conducted. The bigger size of wood powder resulted in the higher bulk and the higher drainage efficiency, but the lower paper strength. The drying efficiency were in detail evaluated depending on the drying process level. In the first section of drying process until the 80% solid level, there were no significant changes in the drying efficiency by the addition of wood powder. However, after the 80 % solid level, the drying efficiency was greatly improved by the addition of wood powder. Those results showed the addition of wood powder could greatly affect not only the drainage in forming and wet pressing but also the drying process.

• Korean Journal of Environmental Agriculture
• /
• v.30 no.1
• /
• pp.37-42
• /
• 2011

BACKGROUND: The purpose of this study was to evaluate ecological function of small-scale pond and movement characteristics of mudfish (Misgurnus mizolepis) during midsummer drainage period. METHODS AND RESULTS: In situ experiments were performed in the paddy field with mudfish under the condition of midsummer drainage from 13 July to 29 July 2010. The mudfish used in this experiment is approximately 1,000 individuals with a cut tail. Mudfishs were released in the rice field before midsummer drainage and caught again in the small-scale pond and the paddy field after midsummer drainage. Results showed that the abundance of mudfish was higher in drainage canal than small-scale pond at the early stage of midsummer drainage, because flow was formed toward the drainage canal. In that time, 3% of the total marked mudfish were captured at outlet of drainage canal. As the paddy was drying, 5% of total marked mudfish moved to the small-scale pond during midsummer drainage period. Contrary to the general hypothesis, the marked mudfish was not found in holes in paddy field.of total caught in the small-scale pond ingested mainly animal prey, and it's frequency of empcy stomach was 10%.oOn the other hand, all m total collected in the paddy field showed empcy stomach. It was apparent from the experiment that m total are eeldng normally in the small-scale pond, while m total are not eat properly in paddy field. CONCLUSION(s): As the paddy was drying, mudfish moved to the small-scale pond during midsummer drainage period but mudfish was not found in holes in paddy field. It can be concluded that small-scale provides a shelter and prey to mudfish in the midsummer drainage period.

• Proceedings of the Korea Technical Association of the Pulp and Paper Industry Conference
• /
• 2000.04a
• /
• pp.71-71
• /
• 2000

Recycled fibers usually give slow drainage in the paper forming zone on papermachine, which limit the application of more refining to the fibers for improving paper strength and formation. To use recycled fibers, especially, OCC, more effectively, developing very efficient handling technique of short fibers and fines is inevitable. We tried to make hard flocs of fractionated short fibers and fines, which were the main cause of slow drainage, by adding excessive amount of retention aid on them. This technique was proved to increase drainage with no difference in strength properties, compared to the conventional technique of adding the same amount of polymers to the whole furnish in the lab test. The bonding capability of short fibers and fines in Korean OCC were very poor to be considered as ´fillers´in paper products. Various chemical treatment on the short fibers and fines of the Korean OCC did not improve their bonding and optical properties. One of the reasons of no improvement in their properties was thought to be their high amount of ashes (over 30% in the fractionated samples).

• Journal of The Korean Society of Agricultural Engineers
• /
• v.65 no.4
• /
• pp.25-32
• /
• 2023

KDS (Korean Design Standard) for agricultural drainage is a planning standard that helps determine the appropriate capacity and type of drainage facilities. The objective of this study was to analyze the inundation of the agricultural basin considering the current design standard and the critical rainfall duration. This study used the rainfall durations of 1-48 hour, and the time distribution method with the Chicago and the modified Huff model. For the runoff model, the NRCS (Natural Resources Conservation Service) unit hydrograph method was applied, and the inundation depth and duration were analyzed using area-elevation data. From the inundation analysis using the modified Huff method with different rainfall durations, 4 hours showed the largest peak discharge, and 11 hours showed the largest inundation depth. From the comparison analysis with the current method (Chicago method with a duration of 48 hours) and the modified Huff method applying critical rainfall duration, the current method showed less peak discharge and lower inundation depth compared to the modified Huff method. From the simulation of changing values of drainage rate, the duration of 11 hours showed larger inundation depth and duration compared to the duration of 4 hours. Accordingly, the modified Huff method with the critical rainfall duration would likely be a safer design than the current method. Also, a process of choosing a design hydrograph considering the inundation depth and duration is needed to apply the critical rainfall duration. This study is expected to be helpful for the theoretical basis of the agricultural drainage design standards.

• Journal of Korea Technical Association of The Pulp and Paper Industry
• /
• v.40 no.2
• /
• pp.1-7
• /
• 2008

The trend of using more hardwood and recycled fibers, and closing more tightly of the paper mill white water system has resulted in build-up of fines as well as organic and inorganic contaminants in the white water. This changes in papermaking wet end requires developing chemical additive system that provides good fiber retention and drainage in closed white water system. In this study the effect of charge densities and chemical characteristics of microparticle systems consisted of cationic guar gums and anionic colloidal silica sols on drainage and retention have been examined. Results showed that higher charge density of cationic guar gum and anionic colloidal silica sol gave better retention and drainage. Particularly highly structured silica gave greater retention efficiency.

• Proceedings of the Korean Society of Crop Science Conference
• /
• 1994.06a
• /
• pp.122-123
• /
• 1994

• Journal of Korea Technical Association of The Pulp and Paper Industry
• /
• v.43 no.3
• /
• pp.21-29
• /
• 2011

Recently, the use of recycled fibers was increased in order to replace the virgin pulp for low production cost and forest conservation. However, the recycled fibers decreases drainage rate, papermaking efficiency and product quality by short fibers and low wettability because of hornification. To overcome the limitation of low drainage rate, the technology of organic fillers were applied. Wooden fillers gave high bulk and stiffness of paper, but they reduced the strength of paper. In order to improve strength properties 4 types of strength additives were added and analyzed. Cationic starch, branched strength additive, linear wet strength additive, and linear dry strength additive were used. The drainage rate and paper properties such as bulk, air permeability and tensile strength were measured. As results of analysis, addition of branch type of strength agent such as C-starch was effective than linear type of strength agent in the drainage rate. Nevertheless there was no effect on the drainage rate by adding the pretreated wooden fillers. By adding the pretreated wooden fillers, bulk, air permeability and tensile strength of handsheets were improved with low dosage than non-pretreated fillers.