• Journal of the Korean Society of Tobacco Science
• /
• v.25 no.1
• /
• pp.34-38
• /
• 2003

This study was carried out to investigate the changes of dehydration process and quality of cured leaves with crushed midribs and cut of the yellowed leaves during drying stage of flue-cured tobacco. The crushed midribs of yellowed leaf dried out before raising the highest temperature of midrib drying stage and reduced the curing time by about 20 hours. However, the cut of yellowed leaf was not affected the curing time and dehydration process during drying stage of flue-curing due to a problem with the cut leaves packing excessively in the curing container. The cured weight yield was increased with crushed midrib and cut leaves, and nicotine and sugar contents of cured leaves and quality in terms of dollars per kilogram were decreased with crushed midrib and cut leaves.

• Advances in concrete construction
• /
• v.7 no.4
• /
• pp.277-288
• /
• 2019

The formulation of self-compacting concretes (SCC) and the study of their properties at the laboratory level were currently well mastered. The aim of this work is to characterize SCC under hot climatic conditions and their effects on the properties of fresh and hardened SCC. Particularly, the effect of the initial wet curing time on the mechanical behavior such as the compressive strength and the durability of the SCCs (acid and sulfate attack) as well as the microstructure of SCCs mixtures. In this study, we used two types of cement, Portland cement and slag cement, three water/binder (W/B) ratio (0.32, 0.38 and 0.44) and five curing modes. The obtained results shows that the compressive strength is strongly influenced by the curing methods, 7-days of curing in the water and then followed by a maturing in a hot climate was the optimal duration for the development of a better compressive strength, regardless of the type of binder and the W/B ratio.

• Journal of the Korean Solar Energy Society
• /
• v.39 no.4
• /
• pp.1-9
• /
• 2019

Modules using 6 inch cells have problems with loss due to empty space between cells. To solve this problem made by shingled structure which can generate more power by utilizing empty space by increasing the voltage level than modules made in 6inch cell. Thus, in this paper, the c-Si cutting cells were produced using nanosecond green laser, and then the ECA was sprayed and cured to perform cutting cell bonding. Three types of ECA materials (B1, B2, B3) with Ag as the main component were used, and experimental conditions varied from 5 to 120 seconds of curing time, 130 to $210^{\circ}C$ of curing temperature, and 1 to 3 of curing numbers. As a results of experiments varying curing time, B1 showed efficiency 19.88% in condition of 60 seconds, B2 showed efficiency 20.15% in 90 seconds, and B3 showed efficiency 20.27% in 60 seconds. In addition, experiments with varying curing temperature, It was confirmed highest efficiency that 20.04% in condition of $170^{\circ}C$ with B1, 20.15% in condition of $150^{\circ}C$ with B2, 20.27% in condition of $150^{\circ}C$ with B3. These are because the Ag particles are densely formed on the surface to make the conduction path. After optimizing the conditions of temperature and curing time, the secondary-tertiary curing experiments were carried out. as the structural analysis, conditions of secondary-tertiary curing showed cracks that due to damp heat aging. As a result, it was found that the ECA B3 had the highest efficiency of 20.27% in condition of 60 seconds of curing time, $150^{\circ}C$ of curing temperature, and single number of curing, and that it was suitable for the manufacture of Solar cell of shingled structure rather than ECA B1 and B2 materials.

• Proceedings of the Korea Concrete Institute Conference
• /
• 1997.10a
• /
• pp.143-150
• /
• 1997

The maturity concept was adopted to predict the strength of concrete, which was subjected to same temperature conditions and variable curing conditions. Penetration test and compressive test were conducted to measure the initial and final setting time and the compressible strength of concrete specimen, respectively. Also, the temperature and time were recorded at some intervals of time for calculating the maturity. The initial and final setting were delayed as the w/c ratio increased and curing temperature decreased. The activating energy decreased as the w/c ratio increased. The relationships at the relative strength and the maturity were proposed at different w/c ratio for the same temperature curing condition, and these were applied for the variable curing conditions. The results indicated that the difference between the strength of the proposed and the specimen was big at 1 days's age but quite similar after 3 day's age.

• Journal of Ocean Engineering and Technology
• /
• v.15 no.2
• /
• pp.124-129
• /
• 2001

The research on anticorrosive of valve for ship, waterworks, and drainage system is very important. The purpose of this paper is to develop the metal/polyurethan adhesive technique at insider of the value to prevent corrosion in the value. It is performed to the bending strength test by using metal /polyurethan in the metals (SB41, Al6061). It is investigated to the effects of bending strength on curing temperature, preheating time and curing time, and to the fracture mechanism of metal/polyurethan adhensived specimen. As a results, we find that the bending strength is the highest at curing temperature of 11$0^{\circ}C$ and the curing time is 60 minutes in metal/polyurethan adhesive specimen.

• Proceedings of the Korean Institute of Building Construction Conference
• /
• 2023.11a
• /
• pp.187-188
• /
• 2023

This study aimed to evaluate a feasibility of estimating setting time and compressive strength of curing conditions using a Hybrid meter. As a result, It was determined that the measured hardness value at the initial set, final set and at 5MPa of the Hybrid meter were not affected by curing conditions. And the Hybrid meter(A) is confirmed to have a higher correlation, so it is judged to be more suitable for pratical use.

• Journal of the Korean Society of Tobacco Science
• /
• v.5 no.1
• /
• pp.35-42
• /
• 1983

This study was conducted to know changes in chemical components and some enzyme activity on tobacco leaves of NC2326 and Hyangchio (Nicotiana tabacum L. ) by different curing methods. The activity of $\alpha$, $\beta$-amylase and invertase of flue-cured tobacco variety NC2326 were higher than that of sun-cured variety Hyangchio. And the peak of all of enzyme activity in both varieties showed at about 60 hours (at color fixing stage) and 6 days (yellowing stage) after start of flue-curing and sun-curing, respectively. The peak time of reducing sugar content were same with the maximum enzyme activity during curing process in both varieties. During both curing process, the content of starch was greatly reduced and there was a corresponding increase in reducing sugars. Increase in total alkaloids content continued during flue-curing process in both varieties, but during sun-curing process total alkaloids content of NC 2326 were Increased whereas those of Hyangchio were decreased markedly.

• Journal of the Korean Society of Tobacco Science
• /
• v.22 no.1
• /
• pp.13-18
• /
• 2000

All steps of the curing process are automatically controlled by preseted program according to stalk positions in flue-cured tobacco. The bulk curing experiment was carried out to evaluate the effect of the basic and modified curing program in curing time schedule of two bulk models in physical properties of cured leaves in a new flue-cured tobacco variety KF 114(Wicotiano tabacum L.). The curing process of KF 114 was prolonged in yellowing and quicker in browning stage than those of NC 82. There was no significant difference in physical properties and chromatic characteristics of the cured leaves between basic and modified program at two bulk models. The ratio of normal leaf color tended to increase and the greenish leaf decreased in the modified curing program of two models, but no difference in the brownish leaf ratio was olserved between two programs.

• Bulletin of the Korean Chemical Society
• /
• v.20 no.11
• /
• pp.1329-1334
• /
• 1999

The curing characteristics of diglycidyl ether of bisphenol A (DGEBA) with diaminodiphenylmethane (DDM) as a curing agent were studied using differential scanning calorimetry (DSC), rheometrics mechanical spectrometry (RMS), and dielectric analysis (DEA). The isothermal curing kinetics measured by DSC were well represented with the generalized auto-catalytic reaction model. With the temperature sweep, the inverse relationship between complex viscosity measured by RMS and ionic conductivity obtained from DEA was established indicating that the mobility of free ions represented by the ionic conductivity in DEA measurement and the chain segment motion as revealed by the complex viscosity measured from RMS are equivalent. From isothermal curing measurements at several different temperatures, the ionic conductivity contribution was shown to be dominant in the dielectric loss factor at the early stage of cure. The contribution of the dipole relaxation in dielectric loss factor became larger as the curing further proceeded. The critical degrees of cure, at which the dipolar contribution in the dielectric loss factor starts to appear, increases as isothermal curing temperature is increased. The dielectric relaxation time at the same degree of cure was shorter for a sample cured at higher curing temperature.

• KSCE Journal of Civil and Environmental Engineering Research
• /
• v.38 no.1
• /
• pp.19-28
• /
• 2018

The time for form removal is an important factor for ensuring the safety and economical efficiency of concrete structures, because it affects the quality, period, and cost of construction. Although local specifications suggest the form curing time, there is a problem of low quality of concrete due to early removing of form. This is because they do not fully understand effect of curing condition, and they want to shorten construction period in the field. Therefore, this research evaluates the effect of curing condition according to the time for form removal by testing specimen. As a result, the concrete compressive strength at the age of 28 days decreased about 40% in the condition of form removal after 12 hours, while the strength in the condition of form removal after 28 days decreased about 7%. Finally, this paper suggests an estimating equation for the concrete compressive strength due to the time for form removal considering various curing temperatures as equivalent ages. The proposed equation can be used in the field for evaluating the strength after form removal.