• Journal of the Korean Wood Science and Technology
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• v.42 no.4
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• pp.491-498
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• 2014

In order to obtain basic data for concentration control of alkaline copper quat (ACQ) solution in wood preservative treatment, this study investigates the change of concentration and adsorption of treating solution and active ingredient, copper oxide (CuO) and didecyldimethyl ammonium chloride (DDAC), in the process of recycling of ACQ solution. Japanese larch (Larix leptolepis), Douglas-fir (Psedotsuga menziesii) and Radiata pine (Pinus radiata) were treated with ACQ solution. The active ingredient concentration of ACQ solution was decreased continuously with increase of recycling. There are differences between extent of concentration decrease of Cu (as CuO) and DDAC. DDAC was decreased more quickly and to a higher degree than Cu for all recycling. The extent of DDAC concentration decrease was remarkable than that of Cu for wood species. The amount of DDAC adsorbed into wood decreased with the increase of ACQ solution recycling, but adsorption of Cu was little difference regardless of recycling. The adsorption of Cu into wood increased as DDAC concentration decrease by recycling of ACQ solution. This is likely due to decrease of DDAC competition with Cu for the same reaction site in wood.

• Journal of the Korean GEO-environmental Society
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• v.8 no.5
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• pp.23-29
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• 2007

The performance of the improved soil against liquefaction depends upon the chemical density, and it has been decided on the basis of the unconfined compressive strength of the improved soil up to date. On the other hand, several authors have proposed that the stiffness degradation could be treated as the clue for the judgment of the possibility of liquefaction. In this study, therefore, the stiffness degradation of the improved soil was estimated as the resistance against liquefaction by using the strain controlled cyclic triaxial test equipment. Based on the test results, it is concluded that the chemically treated sand can resist against the liquefaction in aspect of the reduction in effective stress and in the stiffness. Furthermore, even in the case of low chemical density, such as 2% in this study, has enough liquefaction resistance when compared with the 5~6% which often used in practical design. Considering this fact, the design of chemical density based on the unconfined strength can lead the overestimation in chemical density, and chemical density can be reduced when considering the stiffness reduction shown in this study.

• Journal of the Korean Wood Science and Technology
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• v.44 no.5
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• pp.743-749
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• 2016

The concentration control of wood preservatives is necessary to produce a preservative treated wood having a uniform quality. Concentration measurement method of wood preservatives to be easily used in the field has not been developed yet. This study examined the way to estimate the concentration from turbidity of ACQ wood preservative that can be relatively easily measured by using a portable turbidity meter. The addition of phosphoric acid solution in an alkaline ACQ solution having a very low turbidity is created a suspension of the white substance and the turbidity suddenly increased. The optimum amount of addition of the phosphoric acid solution is until the pH of ACQ solution reaches 7, the turbidity of the ACQ solution reaches maximum value. Excessive addition of the phosphoric acid solution results in a turbidity decrease with acidification of the ACQ solution. Also ACQ solution becomes transparent. The high significance was recognized with positive correlation between the concentration and the turbidity of the ACQ solution. From the t-test, The significant difference between the actually measured concentrations and the concentrations predicted by the regression equation for industrial ACQ solutions was not recognized. Thus, it was possible to know that concentration prediction and control of industrial ACQ solution using the turbidity and a regression equation. Therefore, using the regression equation and turbidity is expected to be able to management the concentration of ACQ solution in the industrial field.

• Journal of the Korean Geotechnical Society
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• v.39 no.8
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• pp.41-48
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• 2023

Microbially induced calcite precipitation(MICP) is a novel cementation method meant to enhance soil engineering properties through the use of microorganisms. This study investigates the effect of different MICP concentrations on plant growth. Tall fescue seeds are grown in plant columns filled with Jumunjin sand. Following plant growth, the soil samples are treated with MICP via spraying method. The results indicate that the MICP-treated plants exhibit hampered growth compared with the untreated plants. pH and electrical conductivity(EC) tests are performed to analyze the changes in soil properties by MICP. The MICP-treated soils exhibit a pH = 7, similar to the untreated soil. However, the EC dramatically increases with the increase in the MICP concentration, which leads to an increase in the osmotic pressure of the soil surrounding the plant roots. Eventually, the higher osmotic pressure in MICP-treated soil hinders the absorption of water and nutrients in plant roots, thus inhibiting plant growth.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.11 no.4
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• pp.189-200
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• 1991

The purpose of this study is to examine the cut-off effect in aquifer by chemical grouting. Moreover, injection tests using specially prepared injection equipment of 1.5 shot system which hydrauric condition can be controlled are attempted to investigate the cut-off effect by confirming the gelling condition of samples according to the variation of flow velosity. And the permeability is measured according to changing of time by falling head test in order to consider the durability of grouts. Therefore to increase the cut-off effect in groundwater flow, shortening the gel-time according to the increasement of flow velocity, increasing the concentration and quantity of grouts(grouting ratio) according to the increasement of that, and as another direct method, contracting the distance between grouting holes or enlarging the grouting line should be done. These coefficients should be designed by data based on injection test in laboratory and field.

• Magazine of the Korean Society of Agricultural Engineers
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• v.8 no.2
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• pp.1200-1212
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• 1966

• Magazine of the Korean Society of Agricultural Engineers
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• v.11 no.2
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• pp.1638-1643
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• 1969

• Journal of Korean Society of Forest Science
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• v.64 no.1
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• pp.26-32
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• 1984

This research was conducted to examine the effect of bonding on the bending and shear strength of COMPLY-board when used with meranti face veneer and fire retardant treated particle-board core. For ammonium sulfate, modulus of rupture (MOR) of COMPLY-board increased with increasing chemical concentration up to 10 percent and then decreased after that concentration. However, Minalith showed reverse effect to the result for ammonium sulfate. Modulus of elasticity (MOE) of COMPLY-hoard decreased with increasing chemical concentration and its differences were not significant between concentration. Shear strength was shown better when treated with ammonium sulfate than with Minalith. Wood failure of COMPLY increased with increasing chemical concentration up to 15 percent and then decreased after that concentration. The products of parallel and cross veneer laminated were better than those of COMPLY composed of fire retardant treated particle-board core. Non-treated particle-board was the least in strength. MOE of fire retardant treated COMPLY increased by 136 percent and its MOE by 170 percent as compared with non treated particle-board.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.4 no.2
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• pp.89-99
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• 1984

Engineering properties of soils is studied by permeating injection of water-glass chemical grout by use of a large sized grouting equipment of 1.5 shot system. Furthermore, the effectiveness of chemical groutinig by taking water-glass chemical grout combined with portland-cement for the purpose of improving the soil strength is confirmed. Relationships between main factors which cause the effectiveness of chemical grouting are described, and the factors are velocity and temperature of flowing water; grain size distribution and density of soils; density, viscosity, gel time and volume of grouts; injection pressure and grouting process. Improvement of the effectiveness of chemical grouting in flowing water by preventing the dilution and flowing down of grouts is investigated. Moreover, local shear failures and upheaval phenomena of ground are also investigated by field measurement.

• Journal of the Korean GEO-environmental Society
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• v.17 no.9
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• pp.37-45
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• 2016

This study analyzes the environmental and durability problems of traditional (LW) grouting method. And the proposed method was compared to the others effects by analyzing the in-situ applicability and effect of performance of the method using the silica sol. This study analyzed the eco-friendly, effects of high strength silica sol through laboratory tests. The effects of the construction process were identified through the field tests. The compressive strength was increased by 1.3 times compared to the LW method and the shrinkage is 3~8 times less than that of LW method with water glass. No toxicity, which could affect soil contamination. In particular, it was confirmed that the Toxicity fish also survived with little pH change in the concentration tank. Also it confirmed the construction effects through field test. Field tests are a standard penetration test, permeability test, LLT, BST. Permeability was reduced to $1{\times}10^{-5{\sim}-6}cm/sec$.