• Journal of the Korea Concrete Institute
• /
• v.20 no.5
• /
• pp.543-548
• /
• 2008

Solid hydrated by hydro-thermal synthesis reaction is cured two times, the first curing is the steam curing at atmospheric pressure and the second one is a high-pressure steam curing, that is autoclaving. Steam curing is to acquire the proper strength for the resistance of treatment in the first curing process, it was not evaluated properly so far. Because of ignorance about curing, some engineers even think that the dry curing is better than the steam curing. The relation between compressive strength of solid hydrated by hydrothermal synthesis reaction and curing condition are presented in this paper. In order to investigate the effect of curing on the strength properties of specimen, the hydration behavior of solid hydrated by hydro-thermal synthesis reaction has been studied over curing condition using XRD, DT-TGA and porosimeter, SEM analysis technique. The results show that the specimens which are cured with blended method of dry and steam curing appear to have better strength properties than that of dry curing and steam curing. Also, there are significant difference of hydration behavior among curing condition in the solid hydrated by hydro-thermal synthesis reaction.

• Proceedings of the Korean Society of Crop Science Conference
• /
• 2017.06a
• /
• pp.39-39
• /
• 2017

In Asia, sweet potato (Ipomoea batatas) is a very important crop for starch production. Approximately 74.3% of the total sweet potato production quantity is produced in Asia (FAO, 2014) and China is the largest producer of sweet potato. Post-harvest management is particularly important because it is difficult to maintain the quality as well as quantity of sweet potatoes. Despite the importance of post-harvest management, researches on sweet potato have been focused on production-related study such as breeding of new variety, improved techniques of cultivation, so there is limited research on storage after harvest. Curing is a normal practice after sweet potato harvest to promote wound healing and extend postharvest storage life. In Korea, harvested sweet potatoes are usually cured for 4 to 7 days at $30-33^{\circ}C$ and 80-95% relative humidity within one week. Since the optimum storage temperature of sweet potato is regarded as $15-20^{\circ}C$, additional facilities and costs are required to raise the temperature for curing. However, the majority of small farmers do not have the capacity to provide additional facilities and costs. This study was initiated to suggest a new curing method to accelerate the wound healing by applying chemical oxidation to the wound surface of sweet potato. Oxidative stress is known to play an important role in the synthesis of secondary metabolites including lignin. In addition, chemical oxidation can be applied to prevent spoilage caused by microorganisms. Powerful gaseous oxidant with excellent penetration ability and superior sterilization effect was selected for this study. Lignification, weight loss, and spoilage rate of artificially wounded sweet potatoes were investigated after oxidant fumigation. There were clear differences in morphological analysis such as lignification pattern, lignin deposition color, and continuity of lignified cell layers between oxidant-fumigated sweet potatoes and control. These results show that gaseous oxidant can be used to supplement or replace the curing practice, to improve shelf-life as well as curing cost reduction.

• Proceedings of the Korean Institute of Building Construction Conference
• /
• 2015.11a
• /
• pp.49-50
• /
• 2015

Recently, by-products from concrete industry are generated in large quantities because of urban redevelopment. Accordingly, waste concrete powder(WCP) inevitably generated in the course of crushing, screening, and separating the waste concrete also show high emission and be increasing gradually, but which is mostly buried with waste concrete aggregate. This is a basic research to increase the value added utilization rate of WCP. We have examined strength characteristic of extruding panel with WCP, depending on the curing methods. The result of study shows similar strength to the base specimen in autoclave curing condition. And in autoclave curing condition, the specimen with WCP of 20% and 30% satisfy the target strength of 14MPa.

• Proceedings of the Korea Concrete Institute Conference
• /
• 2001.05a
• /
• pp.769-774
• /
• 2001

The purpose of this study is to analyze the curing effect of heating cable for concreting in cold weather. An experiment was conducted to evaluate the temperature history of concrete structures cured with embedded heating cables. Results are as follows : In comparison with the non-heating case, applying of heating cable resulted in the rise of temperature in the range of $10^{\circ}C$. In order to get successful results, the optimal pitch length for the embedded heating cables ranged from 20cm to 25cm. When working with the existing curing methods, applying this heating cable would be more effective in concrete curing. Finally, a formula and process was suggested to predict the Internal temperature history of concrete structures under the various curing conditions.

• Proceedings of the Korea Concrete Institute Conference
• /
• 2009.05a
• /
• pp.365-366
• /
• 2009

Humidity curing of the concrete after placing is significant to ensure the crack resistance, strength, and durability. Generally, there are watering and sheet curing methods as humidity curing methods to the upper part of slab concrete, therefore this study investigates effects of these curing methods to preservation of humidity on the cement mortar.

• Journal of Korean Society for Quality Management
• /
• v.16 no.1
• /
• pp.43-48
• /
• 1988

Most of silicone used for water repellent finish is MHP (methyl hydrodiene polysiloxane), which is formed by hydrolysis and condensation polymerization of MHD (methyl hydrodiene dichlorosilane: Me H Si $Cl_2$). The cross-linking theory explains the water repellent mechanism of MHP. The silicone finish on fiber could improve in handle, softness, abrasion resistance, soil repellency, tear strength and crease resistance, as well as water repellency. According to using method silicone-water repellent finishing agents, could be devided into air dry type and curing type. MHP is the typical curing type of water repellent finishing agent, and this type requires the curing temperature above $150^{\circ}C$ at least. High curing temperature is the very drawback of this curing type. For this reason, there has been global interest in the lowering of its temperature. The objective of this study is to investigate merits of alkali treatment for silicone finishing by ANOVA and LSD (least significant difference).

• Journal of the Korean Society of Tobacco Science
• /
• v.21 no.2
• /
• pp.182-187
• /
• 1999

A bulk curing experiment was carried out to evaluate the effect of air flow reduction in the bulk barn from color fixing stage in the chemical properties of cured leaves, The air flow was controlled by reducing air velocity of a blower from 0.3m/sec to 0.2m/sec using a boltage regulator(Slidac). The bulk curing before color fixing stage was processed in the conventional curing method. Reduction of air circulation in bulk barn did not affected so much on change of the contents of the main chemical components in cured leaved, such as nicotine, total sugar, total nitrogen, petroleum ether extract, and organic acids. Only a slight increase in essential oil contents, such as solanone, damascenone, damascone, $\beta$-ionone, and megastigmatrienone isomer, could be observed in leaves cured in the reduced air flow.

• Proceedings of the Korean Society For Composite Materials Conference
• /
• 2003.04a
• /
• pp.192-195
• /
• 2003

UV curing technology becomes important in various sectors of applications due to the high efficiency, environmental protection and saving energy. Above all, It is necessary to consider the formulation of glass fiber sizes in some detail to achieve this study since they are governed by the products to be made and their performance in the composites made form them. The effect of glass fiber sizes against UV curing system was investigated by the method of changing size formulation. Nanosil 700 was used in order to increase curing efficiency. Yellow effect was not observed at the 1% fiber sizer content.

• Computers and Concrete
• /
• v.16 no.3
• /
• pp.487-502
• /
• 2015

This study investigated particle expansion in basic oxygen furnace slag (BOF) and desulfurization slag (DSS) after heat curing by using the volume method. Concrete hydration was accelerated by heat curing. The compressive strength, ultrasonic pulse velocity, and resistivity of the concrete were analyzed. Maximum expansion occurred in the BOF and DSS samples containing 0.30-0.60 mm and 0.60-1.18 mm particles, respectively. Deterioration was more severe in the BOF samples. In the slag aggregates for the complete replacement of fine aggregate, severe fractures occurred in both the BOF and DSS samples. Scanning electron microscopy revealed excess CH after curing, which caused peripheral hydration products to become extruded, resulting in fracture.

• Magazine of the Korean Society of Agricultural Engineers
• /
• v.44 no.2
• /
• pp.99-106
• /
• 2002

This study is performed to examine pH reduction by neutralization treatment and curing condition of porous concrete using rice straw ash for planting. Test results show that pH of porous concrete without neutralization treatment in the dry and water curing is 10.34 ∼ 10.57 and 9.42 ∼ 9.72, respectively. pH of porous concrete by neutralization treatment in the dry and water curing is 9.72 ∼ 10.03 and 9.00 ∼ 9.37, respectively. Accordingly, the best method for pH reduction of porous concrete for planting is to use water curing and neutralization treatment.