• KCID journal
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• v.21 no.1
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• pp.32-44
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• 2014

In Korea, global warming caused by the climate changes impacted on weather system with increase in frequency and intensity of precipitation, and the rainfall pattern changes significantly by regional groups. Furthermore, it is expected that the regional and annual fluctuation ranges of the rainfall in the future would be more severe. Nowadays, agricultural drainage system designed by the existing standard of 20-year return period and 2 days of fixation time cannot deal with the increment rainfall such as localized heavy rain and local torrential rainfalls. Therefore, it is required to reinforce the standard of the drainage system in order to reduce the agricultural flood damage brought by unusual weather. In addition, it is needed to improve the standard of agricultural drainage design in order to cultivate farm products in paddy fields as facility vegetable cultivation and up-land field crop have been damaged by the moisture injury and flooding. In order to prepare for the changes of rainfall pattern due to climate changes and improve the agricultural drainage design standards by the increase of cultivating farm products, the purpose of this study is to examine the impact of climate changes, the changes of relative design standard, and the analytic situation of agricultural flood damages, to consider the drainage design standard revision, and finally to prepare for enhanced agricultural drainage design standards.

• Journal of Korea Technical Association of The Pulp and Paper Industry
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• v.30 no.4
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• pp.11-17
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• 1998

Reducing the effluent discharge from a paper mill is urgently needed due to tightening environmental regulations and economic reasons. For a paper mill to respond to system closure it is required to adopt the best practical retention system that enables the mill to improve fines retention and drainage. In this study, effects of various retention agents on fines retention, drainage and formation were examined using linerboard stock in the laboratory. Among the retention aids tested, high molecular weight cationic polyacrylamides showed good efficiency both in retention and drainage. On the other hand, high charge density, low molecular weight polymeric retention aids showed little improvement both in retention and drainage. The best retention system selected from the laboratory experiment was applied on a paper machine producing linerboard to evaluate its effect on papermaking system closure.

• Magazine of the Korean Society of Agricultural Engineers
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• v.38 no.4
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• pp.125-136
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• 1996

In order to investigate the characteristics of gravity drainage for geotextile, small-scale model tests for the geotextile chimney drain of earth dam which is a typical type of gravity drainage were carried out using 15 kinds of nonwoven and composite geotextiles. According to the results of this study, the drainage discharge of geotexgile drain generally increases with exponential function as hydraulic head increases and the increasing rate is greater in the coarser soil of dam material. It has a trend to increase when the construction slope of geotextile drain is steeper and the number of layers of geotextile is more. The relationship between the transmissivity of geotextile and the drainage discharge has positive correlation and the rate of increase is greater in the coarser soil. The geotextile products must be carefully selected in consideration of transmissivity of geotextile when the soil to be drained is coarser and the seepage flow is relatively high. Most of staple fiber nonwoven geotextile used in this study are found to be appropriate for drainage purpose. Among them, the composite geotextile the type of which geotextile is evaluated to be the most excellent material. But the geotextile of low permeability such as filament thermal bonded and filament spunbonded nowovens closely examined their transmissivity especially to be used for drainage function.

• Journal of the Korean GEO-environmental Society
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• v.14 no.10
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• pp.49-57
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• 2013

Recently, recycling of the industrial by-products has been an important issue of the Yeosu bay, where large industrial complex is located. Major industrial by-products which are produced from Yeosu industrial complex area are phosphogypsum and flyash, which are about 82% and 10% of the 1.6 million tons industrial by-products. Moreover since the Yeosu industrial complex is located at seaside, phosphogypsum has been pointed as cause of serious environmental contaminant from the regional society. Therefore recycling study can't be delayed anymore. In this paper, artificial aggregate was manufactured by non-sintering process from industrial byproducts - e.g., phosphogypsum and slag - as a geotechnical drainage material. To show the feasibility of the artificial aggregate as a geotechnical drainage material, geotechnical experiments including particle size analysis, permeability test, and large scale direct shear test were carried out. Test results show that the permeability of the artificial aggregates range from $6.94{\times}10^{-1}cm/sec$ to $8.86{\times}10^{-1}cm/sec$, which is much larger value than those are required for the drainage material from the construction specification in Korea, and the friction angle of the artificial aggregate is as large as that of sand in water immersion conditions. From the test results, it was concluded that artificial aggregate made from industrial by-products can be used successfully as a geotechnical drainage material.

• Proceedings of the Korea Technical Association of the Pulp and Paper Industry Conference
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• 2006.06b
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• pp.239-243
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• 2006

Papermaking has changed remarkably during the past 20 years, creating huge pressures on retention and drainage programs. During this time, technology has advanced from single PAM flocculants to inorganic microparticle-based programs and then to micropolymer-based programs. In today's evolving fine paper market, retention and drainage programs have to meet increased demands in many areas, such as increased speed, GAP formers, dilution headboxes, higher ash levels, reduced furnish quality, lower cost, and increased machine efficiency. Hercules recently introduced a new technology that offers performance and stability improvements and operational cost savings as compared to existing advanced technologies. $PerForm(R)$ SP Advanced Retention and Drainage Technology consists of a family of products based on a structured organic particulate that offers papermakers the ultimate flexibility for management of wet end chemistry. This paper compares $PerForm(R)$ SP Advanced Retention and Drainage Technology to inorganic microparticle and micropolymer technologies and provides multiple case histories on machines that demonstrate the benefits of the technology. In these case histories, the PerForm SP is shown to provide improved retention and drainage that results in improved performance and operational cost savings to the mill.

• Proceedings of the Korea Technical Association of the Pulp and Paper Industry Conference
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• 2006.06b
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• pp.433-440
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• 2006

A fiber processing method, which might be an alternative for conventional refining process, was introduced. The method consists of repetitive, gentle, mechanical impacts on fiber, and ensued fiber uncurling process. This method was very effective for OCC and BCTMP for increasing WRVs (water retention value) while keeping fiber lengths from shortening. For OCC and BCTMP, gentle mechanical impacts on fibers using Hobart mixer increased breaking lengths and tear strengths simultaneously at fast drainage level, and straightening fibers using kady mill increased those strength properties further. For SwBKP and HwBKP, only mechanical impacts using the mixer were effective on increasing tensile and tear strength at fast drainage, but not kady mill treatment. The strength increases of BCTMP by this alternative fiber processing method were exceptionally high. An extensive engineering development should be followed to actualize this fiber processing mechanism in an energy-effect way.

• Journal of Soil and Groundwater Environment
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• v.15 no.4
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• pp.46-52
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• 2010

Acid mine drainage occurs when sulfide minerals are exposed to an oxidizing environment. The objective of this study was to inhibit the oxidation of pyrite by applying various coating agent such as $KH_2PO_4$, MgO and $KMnO_4$ over its surface as an oxidation inhibitors. Experiments were conducted for 8 days to test the feasibility of oxidation inhibitors. The optimal condition of coating agent for standard pyrite and IK mine was the combination of 0.01M $KH_2PO_4$, 0.01M NaOAc and 0.01M NaClO. Otherwise, for YD mine the combination of 0.01M $KMnO_4$, 0.01M NaOAc and 0.01M NaClO. The $SO_4^{2-}$ reduction efficiency of pyrite, IK and YD mine samples was 70, 92 and 84%, respectively. For 8 days, no significant increase of $SO_4^{2-}$ from pyrite sample coated with inhibitor was observed. The pH of solution remains in between 4 to 6 for the reaction conditions.

• Journal of the Korean Wood Science and Technology
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• v.26 no.4
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• pp.86-91
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• 1998

The drainage was used to determine the specific filtration resistance for wood and non-wood fibers. The drainage rate is also affected by factors that can be changed on consistency, pressure drop across the mat, basis weight, additives, and viscosity. Recent development of theoretical studies in flow through porous media and filtration operation emphasize the urgent need for more accurate data for porosity and specific filtration resistance. This study was investigated to determine specific filtration resistance of Hw, Sw-BKP and Kenaf fiber by filtration experimental. Freeness levels selected were 150,250,and $350m\ell$ CSF. The average specific filtration resistance decreased as freeness increased and resistance of Sw-BKP was greater than that of Hw-BKP. The filtrate and porosity increased and specific filtration resistance decreased as particle size of fiber increased.

• Journal of Korea Technical Association of The Pulp and Paper Industry
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• v.32 no.3
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• pp.18-24
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• 2000

To evaluate the efficiency of various cationic starches in improving retention drainage and strength properties of newsprints which are being made using extensive amount of domestic recycled wastepapers in a highly closed papermaking system diverse cationic starches have been prepared and tested. In the case of cationic starches with low charge density as the degree of substitution increas-es fines retention increased. Results also showed that the retention efficiency decreased sub-stantially for cationic starches with low DS when the conductivity of white water inceased. Tensile strength increased with the addition of cationic starches and then decreased. On the other hand internal bonding strength increased linearly with the addition of cationic starch. Oxidizing treatment of cationic starch was detrimental for retention and freeness improve-ment. Also crosslinking treatment of wet processed cationic starches made cationic starches less effective in retention and drainage.

• Economic and Environmental Geology
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• v.33 no.5
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• pp.405-415
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• 2000

This study was carried out to understand the formation of acid mine drainage (AMD) by pyrophyllite (so-called Napseok)-rainwater interaction (weathering), dispersion patterns of heavy metals, and patterns of mixing with non-polluted water in the Tongnae pyrophyllite mine. Based on the mass balance and reaction path modeling, using both the geochemistry of water and occurrence of the secondary minerals (weathering products), the geochemical evolution of AMD was simulated by computer code of SOLVEQ and CHILLER. It shows that the pH of stream water is from 6.2 to 7.3 upstream of the Tongnae mine. Close to the mine, the pH decreases to 2. Despite being diluted with non-polluted tributaries, the acidity of mine drainage water maintains as far as downstream. The results of modeling of water-rock interaction show that the activity of hydrogen ion increases (pH decreases), the goncentration of ${HCO_3}^-$ decreases associated with increasing $H^+$ activity, as the reaction is processing. The concentration of ${SO_4}^{2-}$first increases minutely, but later increases rapidly as pH drops below 4.3. The concentrations of cations and heavy metals are controlled by the dissolution of reactants and re-dissolution of derived species (weathering products) according to the pH. The continuous adding of reactive minerals, namely the progressively larger degrees of water-rock interaction, causes the formation of secondary minerals in the following sequence; goethite, then Mn-oxides, then boehmite, then kaolinite, then Ca-nontronite, then Mgnontronite, and finally chalcedony. The results of reaction path modeling agree well with the field data, and offer useful information on the geochemical evolution of AMD. The results of reaction path modeling on the formation of AMD offer useful information for the estimation and the appraisal of pollution caused by water-rock interaction as geological environments. And also, the ones can be used as data for the choice of appropriate remediation technique for AMD.