• Journal of the Korean Wood Science and Technology
• /
• v.51 no.5
• /
• pp.334-344
• /
• 2023

Dregs from the sugar palm (Arenga pinnata) starch industry are considered a waste product of the agricultural industry and have not yet been optimally utilized. Therefore, this study aimed to manufacture particleboards from dregs using different amounts of adhesive and particle size ratios. Sugar palm dregs, which had been separated into fibers and powder/fine particles, were used as raw material for making particleboards. The fiber had an average length of 6.84 ± 3.23 cm, while the fine particles were of a size that passed through size 10 mesh and remained in size 60 mesh. Three ratios of fiber to fine particles (100:0, 75:25, and 50:50 wt%) with three different amounts of sucrose-citric acid adhesive (10, 15, and 20 wt%) were used in this study. Increasing the amount of fine particles and the resin content can improve the physical properties and the internal bond strength of boards made from sugar palm dregs. The fine particles possibly filled the gap between the fibers in the particleboard, while the fibers exhibited a high bending strength. As a result, a high-performance particleboard can be attained by combining the composition ratio of fiber/fine particles and resin content. In this study, particleboards made from fiber/fine particles (75:25 wt%) and adhesive content of 15 wt% and 20 wt% had the mechanical properties that met the requirements of Japanese Industrial Standard (JIS) A 5908 type 18. Sugar palm dregs have the potential to be used as raw materials to create value-added particleboards.

• Proceedings of the Korea Concrete Institute Conference
• /
• 2005.11a
• /
• pp.435-438
• /
• 2005

The effect of content of reactive aggregate on alkali-silica reaction was investigated through the ASTM C 1260 method. The replacement proportions of fine aggregate by reactive aggregate were 25, 50, 75 and $100\%$, respectively. Reactive aggregate and fine aggregate(non-reactive aggregate) used are a metamorphic rock and andesite rock, respectively. The results indicate that the mortar-bar containing $25\%$ replacement of fine aggregate by reactive aggregate shows the lowest expansion but expansion in excess of $0.1\%$ at 16 days, which can distinguished between deleterious and potentially reactive. Although content of reactive aggregate is a small amount, it can cause detrimental expansion due to alkali-silica reaction.

• Journal of the Korea Concrete Institute
• /
• v.12 no.4
• /
• pp.103-111
• /
• 2000

The influence of the improvement of grain shape of the coarse aggregate to the unit powder content of concrete and the fine aggregate ratio for the increase of the flowability and segregation resistance of high performance concrete was examined. According to the experimental results, flowability and compacting of concrete presents best states in the S/a which has the smallest 패야 ratio. The coarse aggregate after improvement of grain shape, that has changed from the 0.68 of spherical rate of disk shape to 0.73, led fine aggregate ratio to be down 6% (i.e from 47% to 41%). The improvement of grain shape of the coarse aggregate also led the lowest unit powder content to be down 60kg/㎥ (ie from 530kg/㎥ to 470kg/㎥). And approximate 10% of unit water content has been reduced as unit powder content was down. However, the compressive strength after the improvement of grain shape of the coarse aggregate decreased to 5% due to decrease of adhesiveness of the aggregate and cement paste.

• Food Science and Biotechnology
• /
• v.18 no.2
• /
• pp.513-518
• /
• 2009

This study was carried out to investigate the changes of yield, total phenolics, saponin content and composition, antimicrobial, and antioxidant activities of various fractions of fine ginseng root (Panax ginseng C.A. Mayer) by maceration method in the order of increasing polarity (hexane, chloroform, ethyl acetate, butanol, and water). Butanol fraction showed the highest total saponin content compare to other fractions. Hexane fraction could harvest significantly high ginsenoside Rg2, Rg1, and Rf (p<0.05). And the contents of ginsenoside Rh1, Rg3, and Rg1 showed relatively higher in the fraction of ethyl acetate than other fractions. The system of hexane-chloroform-ethyl aceate-butanol showed relatively high content of ginsenoside Re, Rd, Rc, Rb3, and Rb1. However, the last fraction of water still remained lots of Rb2 content. The fraction of water was the highest phenolics. The 1,1-diphenyl-2-picryhydrazil, superoxide, and hydroxyl radical scavenging activity of water fraction was higher than the other fractions. In antimicrobial activity, the fraction of hexane showed relatively high antimicrobial activity against Pseudomonas aeruginosa, Salmonella typhimurium, Staphylococcus aureus, Bacillus cereus, and Escherichia coli. And the fractions of the chloroform and ethyl acetate showed higher antimicrobial activities than the other samples in against P. aeruginosa and S. typhimurium.

• Proceedings of the Korea Concrete Institute Conference
• /
• 2004.05a
• /
• pp.368-371
• /
• 2004

It analyzes the quality of the fine aggregate which is reproduced through a dry production process with cyclone and a wet production process. The conclusions of the study are as follows. 1. The recycled fine aggregate through the dry production process with cyclone shows the low rate of absorption and impurity content after the cyclone process. It shows that its density is 2.37, absorption rate is 4.8 and stability is $5.1\%$ and less. Therefore, it satisfies the standards of KS F 2573(recycled aggregate for concrete) as the first grade. 2. The recycled fine aggregate through the wet production process shows the low rate of absorption and foreign substance content after the process of wash and dehydration. It shows that its density is 2.40, absorption rate is 3.12 and stability is $3.2\%$ and less. Therefore, it satisfies the standards of KS F 2573(recycled aggregate for concrete) as the first grade.

• Proceedings of the Korean Geotechical Society Conference
• /
• 2007.09a
• /
• pp.502-513
• /
• 2007

This paper describes the rainfall-induced slope failures caused by infiltration due to prolonged rainfall. The emphasis was on quantifying the effect of fine-grained contents which are influencing on the infiltration rate in the wetting front of initially unsaturated slopes during rainfall. Suction tests by tensiometer were performed for five mixture specimens with varying fine-grained contents and then, numerical analyses for the stability of unsaturated slopes are carried out for different relative densities and mixture portions based on the soil water characteristic curves obtained by GCTS pressure plate. It is shown that the fines are highly influenced on wetting front suction of unsaturated soil slopes. Based on the results, it is found that until 15% fine content is the limit showing different wetting front suction, beyond which the wetting band depth do not affect considerably the stability of unsaturated slopes.

• Journal of the Korean Recycled Construction Resources Institute
• /
• v.8 no.4
• /
• pp.490-497
• /
• 2020

This work has been initiated to find possibility whether recycled fine aggregate can be used as a source of aggregate for structural concrete or not. Two-stage mixing approach was chosen in order to maximize strength potential from recycled fine aggregate. Moisture content of the recycled fine aggregate was changed, and two different types of two-stage mixing approaches were applied to produce cement mortar. The strength of mortar made of 100% recycled fine aggregate by two-stage mixing approaches was compared to that of mortar made of 100% washed sea sand. According to the results, the effect of moisture content on compressive strength was observed from low water cement mortar(W/C 0.3). In case of W/C 0.5 cement mortar, no clear relationship was observed between moisture content and strength development. It was found that two-stage mixing approach has a potential to increase the strength of mortar made of 100% recycled fine aggregate. In case of modified version of two-stage mixing approach which first prepares cement paste and pours recycled fine aggregate into the cement paste, was more effective to increase the strength of mortar made of 100% recycled fine aggregate.

• Journal of Ginseng Research
• /
• v.11 no.1
• /
• pp.84-89
• /
• 1987

The contents of some chemical constituents in several parts of Panax ginseng were investigated. Each part of ginseng was extracted with 70% ethanol and then water. The yield of extract was the highest in fine root, and relatively low in roughly dried ginseng and white ginseng, On the other hand, the contents of total sugars in white ginseng and seedling ginseng were high, but low in leaf and peel. The contents of crude protein in roughly dried ginseng and white ginseng were high, but those in leaf, rhizome (nod) and peel were low. The content of crude fat was higher in leaf than in other parts of ginseng plants and that was the lowest in fine root. Among free sugars, the content of fructose was high in leaf and rhizome, but that was the lowest in fine root. In the case of glucose content, leaf contained the highest amount, but fine root did the lowest. Sucrose contents in white, roughly dried and lateral roots were high, whereas that in leaf was low.

• Textile Coloration and Finishing
• /
• v.29 no.4
• /
• pp.211-222
• /
• 2017

In this study, we investigated the dyeing properties of the ultra-fine nylon suede non-woven fabric with Sulphur black dye regarding to the effect of dye concentrations, reducing agent contents, sodium carbonate contents, antioxidant contents, immersion temperature and exposure time in air by pad-steam process. The optimal conditions of dyeing for the ultra-fine nylon suede non-woven fabric were determined with dye concentration of 30% o.w.f., reducing agent content of $9{\sim}13g/{\ell}$, sodium carbonate content of $1{\sim}4g/{\ell}$, antioxidant content of $1{\sim}5g/{\ell}$, immersion temperature of $70^{\circ}C$, exposure time of 20 minutes in air and immersion time of 1 minute, respectively. Meanwhile, the colorfastness to washing, the colorfastness to light, and the colorfastness to perspiration for dyed ultra-fine nylon suede non-woven fabric were achieved in the range of 4-5 grades. The formaldehyde and arylamine were not detected on the ultra-fine nylon suede non-woven fabric by KC tests.

• Journal of the Korean Geosynthetics Society
• /
• v.16 no.4
• /
• pp.57-66
• /
• 2017

Self-weight consolidation test and soil property of dredged soil at Incheon habour route were analyzed to determine the initial dredging reclamation amount, reclamation depth, and estimating the required time of self-weight consolidation with calculation of the final planned height of dredging reclamation site. The moisture content, void ratio and ratio of volume change with elapsed time after throwing were estimated through Yano's empirical equation. As a result, there was a less variation in elements when fine-grained soil content was low as similarly to the behavior of coefficient of sedimentation-consolidation, Cs and the highest variation was shown at the fine-grained soil content of 50%. The retention ratio according to the fine grained soil content that could reinforce the comprehensive aspect of retention ratio for each particle size presented in the standard of estimate for reclamation construction work was calculated and presented using the calculated ratio of volume change.