• Journal of the Korean Society of Tobacco Science
• /
• v.24 no.2
• /
• pp.75-81
• /
• 2002

This study was performed to investigate the influence of curing conditions on the composition of essential oil during curing process of burley tobacco leaves. The curing conditions were the primed curing in vinyl house (house-curing), air-curing barn (air-curing) and stalk-curing in conventional curing house (stalk-curing). Total 90 compounds are identified from the steam volatile oils of harvest and cured tobacco leaves by GC and GC-MS, respectively. The major components were neophytadiene, hexadecanoic acid, 3,8,13-duvatriene-1,5-diols, oxide-9-methylene-3,13-duvadienols, solanone, megastigma-4,6,8-trien-3-ones, phenylacetaldehyde, $\beta$-phenylethyl alcohol, indole, dihydroactinidiolide and phytol. The amount of alcoholic compounds was decreased more than approximately 50% in cured leaves without regard to the curing conditions. $\beta$-Phenylethyl alcohol and 3,8,13-duvatriene-1,5-diols were decreased more in air curing and stalk curing than in house curing. The amounts of phenylacetaldehyde, solanone, $\beta$-damascone, $\beta$ -damascenone, oxysolanone and megastigma-4,6,8-trien-3-ones as ketonic compounds, dihydroactinidiolide and indole as miscellaneous compounds in air-cured and stalk-cured tobacco leaves were 2 times higher than those in house-cured leaves, while esteric and acidic compounds were not changed largely in content by curing conditions.

• Magazine of the Korean Society of Agricultural Engineers
• /
• v.26 no.3
• /
• pp.46-58
• /
• 1984

This study was carried out to investigate the compressive strength and the other effects varying to seasons and curing days on the wet curing conditions of the plain concrete. The results obtained are summarized as follows; 1. The longer the wet curing days and the higher the temperature, the greater the compressive strength was expected. 2.。$_2$8, compressive strength of concrete at 28 days under the dry curing conditions showed a range in 64-76% of that under the wet curing conditions. 3. The seasonal variations in the compressive strength under the wet curing showed in order of summer>spring=autumn>winter, and that under the dry curing were in order of spring ≒autumn> summer> winter. 4. In order to obtain 90% of the design compressive strength, 7 days in spring or autumn and 2 weeks of the wet curing in summer were required. 5. The compressive strength of concrete under the wet curing by using wet straw bag cover was almost the same as that of water curing method. 6. Under the wet curing conditions, the higher the temperature, the greater the effect of the curing of concrete was obtained, however, the compressive strength of concrete was decreased under relatively higher (over 15$^{\circ}$ C) and lower temperature (below 4$^{\circ}$C). 7. Freezing damage was occured when temperature was below 0$^{\circ}$ C and humidity was relatively high. 8. A considerable differnce between estimation of $^{\circ}$$_2$8 from $^{\circ}$7 and measured one was appeared in case of the dry curing conditions. Oregon formula was appeared to be acceptable under the wet curing conditions. 9. In relationship between $^{\circ}$$_2$8 and $^{\circ}$7~, $^{\circ}$28=1. 52 $^{\circ}$7 under the wet curing conditions except winter season, and $^{\circ}$$_2$8 =(1.39-1, 48)$^{\circ}$7 under the dry curing conditions were shown.

• Computers and Concrete
• /
• v.6 no.6
• /
• pp.437-450
• /
• 2009

The effect of six different curing conditions on compressive strength and ultrasonic pulse velocity (UPV) of volcanic pumice concrete (VPC) and normal concrete (NC) has been studied. The curing conditions include water, air, low temperature ($4^{\circ}C$) and different elevated temperatures of up to $110^{\circ}C$. The curing age varies from 3 days to 91 days. The development in the pulse velocity and the compressive strength is found to be higher in full water curing than the other curing conditions. The reduction of pulse velocity and compressive strength is more in high temperature curing conditions and also more in VPC compared to NC. Curing conditions affect the relationship between pulse velocity and compressive strength of both VPC and NC.

• Proceedings of the Korea Concrete Institute Conference
• /
• 2003.05a
• /
• pp.751-756
• /
• 2003

This Paper concerns the compressive strength development tendencies of concrete according to their Ages and curing conditions. The test results are on follows; (1) The compressive strength development of concrete appears larger according to the curing conditions under water curing, condition structural curing and field curing conditions. (2) The compressive strength development rate of concrete after 28 days' curing becomes smaller, but the case of lower strength of concrete not.

• Proceedings of the Korean Institute of Building Construction Conference
• /
• 2023.05a
• /
• pp.377-378
• /
• 2023

This study examined the effect of curing conditions on the compressive strength of dry mortar for floor. The compressive strength according to the relative humidity during curing was compared, and the influence of expansive additives on compressive strength under water curing was reviewed. As a result, low relative humidity conditions during curing was not effective in improving the compressive strength of dry mortar for floor, and it was judged that the continuous hydration reaction insufficient due to lack of the moisture supply. In order to improve compressive strength, high relative humidity maintenance was found to be an important factor. However, under water curing conditions, the compressive strength has decreased as a result of continuous volume expansion due to the use of the expansive additives.

• Proceedings of the Korea Concrete Institute Conference
• /
• 2006.11a
• /
• pp.825-828
• /
• 2006

In this paper, experimental studies are performed to find out properties of crack according to the change of curing conditions of flyash concrete. To study the effect of curing conditions on flyash concrete, slump, bleeding, air content and hydration temperature of fresh concrete are measured according to various curing conditions. In addition, the effect of caring conditions on compressive strength, tensile strength and Plastic drying shrinkage cracking of hardened concrete is also considered.

• Proceedings of the Korea Concrete Institute Conference
• /
• 2006.11a
• /
• pp.441-444
• /
• 2006

Extrusion molding concrete panel is cured two times, that is the steam curing at atmospheric pressure and a high-pressure steam curing(autoclaving). Steam curing at atmospheric pressure is done before autoclaving and to acquire the proper strength for treat in process. Though this curing is the important factor on the quality of product and the speed in manufacturing 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. This study is to investigate the properties of specimen according to variation of curing conditions in the coring chamber such as laboratory scale, pilot plant, and commercial plant. As estimating, in case of steam curing at atmospheric pressure to make extrusion molding concrete panel, moisture curing is better than dry curing and the desirable maximum temperature in curing chamber is about $50^{\circ}C$.

• Proceedings of the Korean Institute of Building Construction Conference
• /
• 2017.11a
• /
• pp.13-14
• /
• 2017

Red mud is an inorganic by-product produced from the mineral processing of alumina from Bauxite ores. This study is to investigate characteristic with respect to curing conditions according to the red mud content. The results best of best showed that the water curing compressive strength better than atmospheric curing, steam curing.

• Proceedings of the Korean Institute of Building Construction Conference
• /
• 2022.04a
• /
• pp.91-92
• /
• 2022

This study is a basic study on carbonation curing technology of concrete using supercritical CO₂, and carbonation curing was carried out by exposing concrete to supercritical CO₂ for a certain period of time. In the case of conventional carbonation curing, long-term curing was performed for several weeks by controlling the concentration of CO₂, but by using supercritical CO₂, more rapid carbonation curing was carried out using constant temperature and pressure conditions to improve durability through surface modification of concrete. This experiment was conducted with the goal of deriving the optimal carbonation curing conditions by measuring the carbonation depth by exposing concrete for a certain period of time to conditions above the supercritical level. As a result, it was confirmed that the carbonation depth increased as the curing time increased, and the curing time could be shortened compared to the carbonation curing according to the existing CO₂ concentration.

• KOREAN JOURNAL OF CROP SCIENCE
• /
• v.45 no.2
• /
• pp.79-82
• /
• 2000

Tuberous root of yacon (Polymnia sonchifolia Poeppig ＆ Endlicher) has not starch, and its brix degree changes during the curing. Therefore its chemical composition changes were investigated according to different curing conditions. Tuberous root contained 87.1% moisture at harvesting, that was decreased to 84.1-86.0% at 30 days after curing in different curing conditions. Brix degree was increased from 5.7 to 14.2-15.8% at 30 days after curing in comparison to at harvesting. Free sugars were detected from tuberous root in yacon by HPLC; that were fructose, glucose and sucrose. Fructose contents were increased from 0.09 to 1.04-1.79% during 30 days in five curing conditions. Glucose contents were shown to increase from 0.03 to 1.04-1.37 %. Sucrose contents were shown to increase from 0.04 to 0.13-0.43%. Tuberous root contained fructose, glucose and sucrose in order of amount that were highest in single-polyethylene film covered green house. Sucrose was little as comparison with fructose and glucose. Fructose and glucose were increased to 16.7 and 40.7 times, respectively, but sucrose was increased little about 6.8 times.