• KCI Concrete Journal
• /
• v.11 no.3
• /
• pp.19-28
• /
• 1999

This study treated self-compacting high Performance concrete as two Phase materials of Paste and aggregates and examined the effect of powder and aggregates on self-compacting high performance, since fluidity and segregation resistance of fresh concrete are changed mainly by paste. To improve the fluidity and self-compactibility of concrete, optimum powder ratio of self-compacting high performance concrete using fly ash and blast-furnace slag as powders were calculated. This study was also designed to provide basic materials for suitable design of mix proportion by evaluating fluidity and compactibility by various volume ratios of fine aggregates, paste, and aggregates. As a result, the more fly ash was replaced, the more confined water ratio was reduced because of higher fluidity. The smallest confined water ratio was determined when 15% blast-furnace slag was replaced. The lowest confined water ratio was acquired when 20% fly ash and 15% blast-furnace slag were replaced together. The optimum fine aggregates ratio with the best compactibility was the fine aggregate ratio with the lowest percentage of void in mixing coarse aggregate and fine aggregate In mixing the high performance concrete. Self-compacting high performance concrete with desirable compactibility required more than minimum of unit volume weight. If the unit volume weight used was less than the minimum, concrete had seriously reduced compactibility.

• Food Science and Preservation
• /
• v.8 no.4
• /
• pp.385-392
• /
• 2001

This study was to investigate the inhibiting effect of electrolyzed oxidizing (EO) water with/without freezing point depressing agents on polyphenol oxidase (PPO) activity of peeled chestnut. 0.85% sodium chloride, 0.5% citron and 0.5% lemon juice were used to freezing point depressing agents. The content of total phenolics was 13.36 mg% at the earlier stage of storage, and then suddenly increased at around 8∼1ldays. At the 11th day, PPO activity of untreated chestnut was 1,152 units, that was higher than any ethers. EO water adding lemon and citron juice showed synergistic effects on the enzyme inhibition, and their PPD activities were 143.3 and 180.22 units after 4 weeks, respectively. Sensory analysis showed that acceptance of peeled chestnuts was dependent on color and taste, which was related to PPO activity and sweetness. The peeled chestnut treated with EO water added citron or lemon juice tended to show the highest score fur acceptance.

• Journal of Navigation and Port Research
• /
• v.31 no.10
• /
• pp.879-884
• /
• 2007

This study is to observe the change of temperature and relative humidity for various vegetables in vacuum precooling system. The materials for experiments were the lettuce, chinese cabbage, pak choi and cabbage. The experimental apparatus was constructed of vacuum chamber, vapor/water separator, water tank, pumps ejecting and cooling water circulation, refrigerator unit, cooling coil for water cooling, Hygrometer and Data logger measuring of the temperature change. The experiments were operated in 20torr and recorded every 3 minutes. It was found that the cooling temperature and speed of vegetables are depending on the percentage of its water content. The more water contains, the faster cooling speed and the lower cooling temperature.

• International Journal of Concrete Structures and Materials
• /
• v.9 no.2
• /
• pp.185-206
• /
• 2015

This paper presents statistical models developed to study the influence of key mix design parameters on the properties of lightweight self-consolidating concrete (LWSCC) with expanded shale (ESH) aggregates. Twenty LWSCC mixtures are designed and tested, where responses (properties) are evaluated to analyze influence of mix design parameters and develop the models. Such responses included slump flow diameter, V-funnel flow time, J-ring flow diameter, J-ring height difference, L-box ratio, filling capacity, sieve segregation, unit weight and compressive strength. The developed models are valid for mixes with 0.30-0.40 water-to-binder ratio, high range water reducing admixture of 0.3-1.2 % (by total content of binder) and total binder content of $410-550kg/m^3$. The models are able to identify the influential mix design parameters and their interactions which can be useful to reduce the test protocol needed for proportioning of LWSCCs. Three industrial class ESH-LWSCC mixtures are developed using statistical models and their performance is validated through test results with good agreement. The developed ESH-LWSCC mixtures are able to satisfy the European EFNARC criteria for self-consolidating concrete.

• Geomechanics and Engineering
• /
• v.30 no.2
• /
• pp.211-218
• /
• 2022

This study characterizes Proctor and geophysical properties in a broad range of grading and fines contents. The results show that soil index properties such as uniformity and fines plasticity control the optimum water content and peak dry unit trends, as well as elastic wave velocity. The capillary pressure at a degree of saturation less than S = 20% plays a critical role in determining the shear wave velocity for poorly graded sandy soils. The reduction in electrical resistivity with a higher water content becomes pronounced as the water phase is connected A parallel set of compaction and geophysical properties of sand-kaolinite mixtures reveal that the threshold boundaries computed from soil index properties adequately capture the transitions from sand-controlled to kaolinite-controlled behavior. In the transitional fines fraction zone between F_F ≈ 20 and 40%, either sand or kaolinite or both sand and kaolinite could dominate the geophysical properties and all other properties associated with soil compaction behavior. Overall, the compaction and geophysical data gathered in this study can be used to gain a first-order approximation of the degree of compaction in the field and produce degree of compaction maps as a function of water content and fines fraction.

• Journal of the Korean Society of Food Science and Nutrition
• /
• v.33 no.4
• /
• pp.736-740
• /
• 2004

Preparation of ginseng concentrate with high content of acidic polysaccharide from white tail ginseng marc that was obtained after preparation of white tail ginseng extract. As a result of extraction of white tail ginseng under various concentrations of ethanol (0∼90%), both amount of acidic polysaccharide and extraction yield decreased by increasing the ethanol concentration. However, acidic polysaccharide extracted by water from white tail ginseng marc was increased in accordance with the increase of ethanol concentration. The optimal condition for the extraction of acidic polysaccharide from the marc was treatment of $\alpha$-amylase in 390∼650 unit/g residue/15 mL of distilled water for 5 min at 4$0^{\circ}C$. The amount of acidic polysaccharide in water extract of the marc was increased from 8.3% to 10.5% by the treatment of $\alpha$-amylase. A new ginseng extract mixture was manufactured by mixing 50% ethanol extract of white tail ginseng and water extract of alcoholic residue in the ratio of 8:2 (w/w). Crude saponin content and acidic polysaccharide content were 10.5% and 17%, respectively. The mixture had a same crude saponin content and twice acidic polysaccharide content comparing to 50% ethanol extract of white tail ginseng. It suggests that preparation of new ginseng concentrate with high content of acidic polysaccharide from white tail ginseng marc has high potencies in the utilization of waste material.

• Journal of Korean Neurosurgical Society
• /
• v.59 no.4
• /
• pp.334-340
• /
• 2016

Objective : The aim of our study was to evaluate the neuroprotective functions of the combination therapy using methylprednisolone (MP) and tranilast (TR) after spinal cord injury (SCI) in adult rats. Methods : Spinal cord compression injury model was achieved using Yasargil aneurysm clip. Rats were divided into control group, MP group, TR group, and combination therapy group using TR and MP. Rat models were assessed for locomotor functional recovery using Basso, Beattie, and Bresnahan (BBB) score, spinal cord water content and myeloperoxidase (MPO) activity 24 hours post SCI, haematoxylin and eosin staining and glial fibrillary acid protein (GFAP) staining at 7 and 14 days post SCI. Results : The spinal cord water content and MPO activity in the combination therapy group was significantly lower than the control group and the individual therapy groups p<0.05. The combination therapy group had significantly higher BBB scores than control group and individual therapy groups (p<0.05). At one week after SCI, GFAP expression in the combination group was significantly lower than the control group (p<0.05) but there was no significant difference compared to the individual therapy groups (p>0.05). At 2 weeks after SCI there was a slight decrease in GFAP expression compared to the first week but the difference was not statistically significant (p>0.05), GFAP expression between the groups was not statistically significant p>0.05. Conclusion : Combining MP and TR is therapeutically more effective in improving functional recovery, inhibiting inflammation and glial scar formation after acute SCI.

• Journal of The Korean Society of Agricultural Engineers
• /
• v.51 no.1
• /
• pp.21-26
• /
• 2009

This study was performed to evaluate the physical and mechanical properties of concrete using waste activated carbon. Materials used were ordinary portlant cement, crushed coarse aggregate, natural fine aggregate, waste activated carbon, and superplasticizer. The substitution ratios of waste activated carbon were 0,1,2,3,4,5,6,7,8,9 and 10%. The unit weight was decreased and water absorption ratio was increased with increasing the waste activated carbon content, respectively. When the substitution ratio of waste activated carbon was 3%, compressive strength, flexural strength and dynamic modulus of elastisity were more higher than that of the ordinary portland cement (OPC), and it was decreased with increasing the waste activated carbon content, respectively. The most effective contents of waste activated carbon was 2% in performance and 4% in practical use Accordingly, waste activated carbon can be used for concrete material.

• Journal of The Korean Society of Agricultural Engineers
• /
• v.50 no.5
• /
• pp.39-50
• /
• 2008

This study are decided the mix proportion method of latex modified concrete for agricultural concrete structures from the results of workability and strength test with mix proportion factor. For mix proportion factor, this study are selected the water-cement ratio, unit cement amount and latex content. Also, this study were performed the slump, compressive strength test and microstructure analysis using the scanning electron microscope(SEM). The strength and slump of LMC are dependent with unit cement amount, latex content, and water-cement ratio. Especially, the strength of LMC are not controlled by single mix proportion factor but effected by combined mix proportion factor. Microstructure investigation are showed the LMC are reduced the internal pore volume and enhanced the transition zone between cement paste and aggregate interface. This effect get by consist of latex films in the concrete. Also, this study were recommended the mix proportion method for LMC. These mix proportions method are estimated the mix design for satisfied the target performance which are applied the agricultural concrete structure.

• Proceedings of the Korean Geotechical Society Conference
• /
• 2000.03b
• /
• pp.591-598
• /
• 2000

In the present study, the variation of settlement, pore water pressure and undrained shear strength through model tests were measured. Also, the variation of water content, unit weight and shear strength by the vane shear tests were observed. In this study, appropriate deposit time of construction equipments used in treatment of hydraulic fills is determined from the prediction curve of increased shear strength in dredged fills.