• Magazine of the Korea Concrete Institute
• /
• v.9 no.1
• /
• pp.143-151
• /
• 1997

Chemical resistance of the cement mortar containing the Thermally Activated Diaomite(TAD) and H.M.(Heavy Metals) has been studied. The H.M.. extracted from EAF(Electrica1 Arc Furnace) Dust. were saturated with diatomite. The diatomite was then thermally activated at $750{\circ}C$ for 30minutes and powdeled. The powder was mixed with a portland cement on a weight basis from 0%. 2.5%. 5.0%. 10%. 20%. The optimum mixture. after those mixtures were subjected to compressive strength(7 and 28days) and leaching bchaviour of H.M.. was tested for its experiment on Wet/Dry cycles and chemical resistance(e.q. imrncrsion in 5%(Conc.) of H2S04, CaC12 and hlgSO4. It was shown that the cement, mortar containing 10% of' P.D. gave a rise to the remarkable increase in compressive strength. The compressive strength was generally decrease beyond the addition of 10% of P.D. The maximum $496kgf/cm^2$ of 28days compressive strength was acheiveti when 10% of P.D. was added to the cement mortar.

• Journal of the Korean Geotechnical Society
• /
• v.33 no.4
• /
• pp.25-34
• /
• 2017

The soil-water characteristics is the most important state parameter for understanding changes in suction and water contents of unsaturated soil slopes. In the field, the hysteretic behaviors of drying and wetting soil-water characteristic curve are real and the adoption of path-dependent suction-water content is needed to predict the hydro-mechanical analysis of unsaturated soils. In this study, in-situ monitored hydraulic behavior of various soil slopes are compared with the data from numerical analysis with the laboratory soil water characteristic curve. Then, the verifications are performed based on the field monitored data respectively. Therefore, the use of path-dependent soil-water characteristic curves could be more rational for design and analysis of unsaturated soil slopes under rainfall conditions.

• Geomechanics and Engineering
• /
• v.23 no.4
• /
• pp.339-349
• /
• 2020

This study investigates the feasibility of using the results of the UPV (ultrasonic pulse velocity) test to assess the UCS (unconfined compressive strength) of unsaturated soil. A series of laboratory tests was conducted on samples of unsaturated lateritic soils of northern Taiwan. Specifically, the unconfined compressive test was combined with the pressure plate test to obtain the unconfined compressive strength and its matric suction (s) of the samples. Soil samples were first compacted at the designated water content and subsequently subjected to the wetting process for saturation and the following drying process to its target suction using the apparatus developed by the authors. The correlations among the UCS, s and UPV were studied. The test results show that both the UCS and UPV significantly increased with the matric suction regardless of the initial compaction condition, but neither the UCS nor UPV obviously varied when the matric suction was less than the air-entry value. In addition, the UCS approximately linearly increased with increasing UPV. According to the investigation of the test results, simplified methods to estimate the UCS using the UPV or matric suction were established. Furthermore, an empirical formula of the matric suction calculated from the UPV was proposed. From the comparison between the predicted values and the test results, the MAPE values of UCS were 4.52-9.98% and were less than 10%, and the MAPE value of matric suction was 17.3% and in the range of 10-20%. Thus, the established formulas have good forecasting accuracy and may be applied to the stability analysis of the unsaturated soil slope. However, further study is warranted for validation.

• Korean Journal of Rural Living Science
• /
• v.8 no.2
• /
• pp.73-81
• /
• 1997

Parsimon juice dyeing is the one of the most popular natural dyeing methods which have been done traditionally among the farmers. The clothes dyed with parsimon juice has several merits, that is, it become much more durable, cool, easy to wash and wear after dyeing and these merits are the reason why people likes to wear the parsimon juice dyeing clothes as work wear. Especially in Cheju province, parsimon juice clothes became a folk costume and many people still enjoy wearing it in the hot summer days. But one of the demerits of parsimon dyeing is that the possible period of dyeing is very short. So, if parsimon juice dyeing could be done with the preserved parsimon juice, it would be possible to enlength the period. With this idea, we compared the color and colorfastness of fabrics which were dyed with 4 kinds of parsimon juice. The experimental parsimon juice 96-8 was preserved during 13 months, 96-9 was 12 months, 97-8 was 1 month and 97-9 was not preserved one. The experimental fabrics were cotton, silk. nylon and polyester fabrics. The results were as follows ; 1. The colors of fabrics dyed with experimental parsimon juice 96-9, 97-8, 97-9 were yellow-red and dyeing states were good. But the colors of fabrics dyed with 96-8 were dark and the state were bad, because the color of experimental parsimon juice 96-8 was changed during preservation. 2. The best state of dyeing could see in the fabrics dyed with experimental parsimon juice 97-8, although that was preserved 1 month. 3. There were differences of color between experimental fabrics dyed with same juice and the colors were thicker in cotton and silk than in nylon and polyester fabrics. 4. During wetting and drying process, the color changes in fabrics dyed with no preserved one were more than in fabrics dyed with preserved ones. 5. The color fastness to the light of the dyed fabrics was over 4, to the acidic perspiration was 3~4 or 4~5, to the alkaline perspiration was 2, 3 or 3~4 and to the washing was 1~2. There was no significant difference in colorfastness between the 96-9 dyed fabrics and 97-9 dyed fabrics.

• Journal of Korean Society of Coastal and Ocean Engineers
• /
• v.19 no.3
• /
• pp.253-265
• /
• 2007

This study applied the previous results of the NAO model, a tidal correction model, to the open boundary condition for the behavior of tidal elevation and tidal currents in the South Sea. This study used the EFDC model considering the wetting and drying problem and using the $\sigma-coordinate$ as a vertical coordinate and generated two mesh cases of the constant grid size of 2.0 km and the variable grid size of $0.5\sim2.0km$. The numerical results for the tides showed that the predicted results were in quite good agreements with the observational data acquired from the tidal stations of the NORI. The predicted tides were observed to propagate from the east area to the west area in the South Sea. The verification results reveal that the numerical results are more correlated with the measured tidal data as the grid size decreases. The grid size of 2 km results in proper simulation of tidal currents in wide waterway and offshore area whereas the numerical results from the grid size of 0.5 km tend to somewhat underestimate the tidal currents affected by narrow waterway and topography in inner-bay.

• Journal of Korean Society of Coastal and Ocean Engineers
• /
• v.21 no.2
• /
• pp.164-173
• /
• 2009

MIKE21, a commercial hydrodynamic model, was applied at the Masan Bay to evaluate the model's applicability of simulating the inundation phenomena. A storm surge/inundation model which adopts overflow computation scheme was applied together for comparison. The results of both models show correspondence with not only observed inundation area but also inundation water depth to prove their ability as inundation models. Especially, the accuracy of the MIKE21 model, which just adopts wetting/drying scheme, does not seem to be behind the inundation model. Moreover, an inundation simulation of the virtual MAEMI which was generated at preceding study, was conducted. The inundation area of the virtual MAEMI is similar to that of the real MAEMI, but inundation water depth is deeper than the real MAEMI.

• Journal of Korea Technical Association of The Pulp and Paper Industry
• /
• v.45 no.4
• /
• pp.52-64
• /
• 2013

This study was carried out to investigate the characteristics of starch paste which was used for the conservation of paper properties. Three kinds of commercial corn starch and five kinds of fermented wheat starch were examined on the contents of amylose and amylopectin, shapes of particles, and viscosity and pH of paste. And adhesive strength on the drying, accelerated aging, and wetting treatments were measured. The contents of amylopectin of oxidized corn starch were higher those of cationic corn starch, unmodified corn starch, and fermented wheat flour. In case of fermented wheat flour, increasing of a fermentation period was resulted in increasing of amylopectin contents. The particle shapes of commercial corn starch showed with a uniform polygon, but fermented wheat flour showed with a mixture of small and large oval types. The viscosity of oxidized corn starch were very lower those of cationic corn starch and unmodified corn starch. And increasing of a fermentation period of wheat flour was resulted in increasing of viscosity. The pH of commercial corn starch were 3.6-7.5 and fermented wheat flour were 3.6-5.2. Through the examination on the nature and adhesive strength of starch paste, the oxidized corn starch 60 cps which is the name of products and wheat flour which had fermented for 5 years were considered that most suitable for conservation of paper properties.

• Research in Plant Disease
• /
• v.7 no.3
• /
• pp.150-154
• /
• 2001

The relationships between the weather conditions and the occurrence of rice bacterial grain rot caused by Burkholderia glumae during the rice heading period, were examined by analying the data accumulated from 1992 through 2000 and by conducting greenhouse and field experiment to develop a model far forecasting the disease. The disease severely occurred in 1994, 1995, 1998, and 2000, when it was high in temperature and rainfall during the heading period of middle-late rice varieties. While it occurred weakly in 1993 was high in rainfall and low temperature and it was reversely in 1997. When treated under wetting condition (above the 24-hour)after inoculation at heading period, the infection rate increased as the inculum concentration increased, it was 86.1% at 10$^{8}$ cfu/ml. When under drying condition, the disease of 12.5% occurred only at $^{8}$ cfu/ml. On the other hand, 1,000 grain weight and the percentage of ripened grains remarkably decreased as the infection rate increased.

• Korean Journal of Soil Science and Fertilizer
• /
• v.48 no.3
• /
• pp.189-193
• /
• 2015

Bad drainage problems from paddy fields adjacent to roads are caused by higher constructed roads which change topography of paddy fields to concave topography and artificial pan to prevent road erosion when road constructions are occurred. This study investigated effects of topography changes on soils by road constructions. Soil samples were investigated by physico-chemical analyses and micromorphology analyses from representative soil profile of Sachon series and soil samples. The characteristics of Sachon series that were adjacent to roads were fewer redoximorphic features (RMF) and increase in grey layers than the original Sachon series. The characteristics of Yecheon Series were shown from Jeollanamdo - Suncheon > Chungchungnamdo - Cheonan > Gangwondo - Wonju. Mosaic speckles were shown from micromorphological analyses because of repeat of shrink and expansion by wetting and drying. The location of graying in soil clods were found from coarse stone blocks to fine stone blocks and color changes of composed particles were also found.

• Journal of Fashion Business
• /
• v.13 no.2
• /
• pp.78-86
• /
• 2009

When scouring and contraction finishing at $90^{\circ}C$ using Relaxer or Rotary Washer contraction and weight loss ratio in warp and weft directions were excellent. Also surface state of fabric after drying or sanding treatment was excellent without crease. Low melting polyester fabric showed a complete melting bond by heat setting(P/S) at above $160^{\circ}C$. The alkali hydrolysis reaction of polyester showed the breakpoint in the weight loss behavior test, polyester yarn showed a breakpoint ranging from 25% to 28%. This is due to the difference of the hydrolysis rate between regular polyester and soluble polyester. Initially the soluble polyester was eluted and micro-fibrillized 5 times faster than a regular polyester. At a later time, a regular polyester was reduced weight to impart a proper flexibility and drape property to the fabric. As a result of surface sanding finishing, the surface of interior fabric showed a surface state most stabilized when using Mesh No. 220 in mono 0.2d after elution finishing. When the rotation direction of sanding roller was pro-, pro-, pro-, and retro-direction, a directional effect of tuft was not shown, a writing effect as suede was exhibited and a surface state was even. Sublimation fastness was 3-4 class for polyester and 2-4 class for nylon. Light fastness 3-4 class after lapse of 100 hours and 2-4 class after lapse of 160 hours. Abrasion fastness was 3-4 class on wet and 4-5 class on dry Laundry fastness was 2-4 class. As such, the abrasion fastness is slightly reduced upon wetting and the use thereof for interior is excellent, whereas laundry fastness is slightly lowered.