• Journal of Korean Society of Steel Construction
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• v.19 no.1
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• pp.79-86
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• 2007

The corrosion durability of steel bridge coatings, such as organic and metallic coatings, is often evaluated by field exposure tests, but such tests take from several years to decades to complete. As a potential method for fast corrosion testing, accelerated exposure tests were considered in this study. The S6-cycle accelerated exposure test, specified in the Japanese Industrial Standards (JIS K5621), was carried out on uncoated structural steels for 30, 60, 90, 120 and 150 days, and the resultant weight loss was determined. The weight loss was compared with that obtained from previous field exposure tests, and acceleration factors of the S6-cycle test to field exposure test sites were determined. The application of the S6-cycle accelerated exposure tests to field environments was presented based on the acceleration factor and the amount of flying salt.

• Journal of the Korea institute for structural maintenance and inspection
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• v.23 no.2
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• pp.75-83
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• 2019

In this study, to propose the deterioration curves of urethane, ceramic, polysiloxane and fluorocarbon coating for the steel bridge, an accelerated corrosion tests were carried out. The each coating system wes applied on the top of the specimens, and circular initial defects were introduced with different diameters with 0.5, 1.0, 3.0, 5.0 mm. An accelerated corrosion test condition was used to simulate severe corrosive environment depending on ISO 20340. The deterioration curve of each coating type was evaluated based on deteriorated area from the circular defects. In order to evaluate the coating service life of installed steel bridge using deterioration curve, the acceleration coefficient was calculated at correlation between ISO 20340 and corrosivity categories by ISO 9223 based on field corrosion rate. From test results, the propagation rate of coating deterioration area was different to diameter of circular defects. In case of urethane coating, the coating service lifes of 3% deterioration area was evaluated in 31.8, 15.8, 9.9 and 3.9 years with C2, C3, C4 and C5 category.

• Applied Biological Chemistry
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• v.21 no.1
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• pp.31-34
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• 1978

The stability of active ingredient of BPMC formulation under ultraviolet lights and sunlights was investigated using dust, emulsifiable concentrate and granular. The active ingredient of BPMC dust was more rapidly degraded by irradiation with ultraviolet lights than emulsifiable concentrate or granular tested. In the case of BPMC emulsions, the degree of degradation was increased in the order of granular, emulsifiable concentrate, dust by irradiation with ultraviolet lights. BPMC was unstable in alkaline solution and ultraviolet lights had highly significant relation to the decomposition of its active ingredient.

• Korean Journal of Agricultural Science
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• v.15 no.1
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• pp.47-68
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• 1988

This study was conducted to define the optimal conditions for embryo growth during seed stratification and for breaking dormancy as well as seed germination of stratified ginseng seeds. The experiments were also carried out to detect some materials which were expected to induce seed dormancy in the ginseng seeds. The results summarized as follows; 1. The growth of embryo during seed stratification was significantly inhibited by the existence of endocarp. The fastest embryo growth was resulted at $15^{\circ}C$ and an estimated optimal temperature for embryo growth was about $18^{\circ}C$. 2. There was no significant difference between the embryo growth and germination ratio of ginseng seeds which were sown in seed bed at Aug-5 without seed stratification and that of artificial seed stratification. 3. Embryo growth and germination ratio was significantly inhibited by high temperature treatment at $30^{\circ}C$ for 24 hours or respiration stress by immersing seeds in water for 10 days or more. 4. When the seed stratification was started at $10^{\circ}C$, growth of embryo in the ginseng seeds were almost stopped. But, when the seeds were stratified first at $20^{\circ}C$ for 50 days and next at $10^{\circ}C$ for 50 days, the embryo growth was significantly promoted compared with the embryo growth in the seeds which were stratified at $20^{\circ}C$ for 100 days. 5. The successive embryo growth after seed stratification was significantly accelerated at $10^{\circ}C$ but the seeds chilled at $5^{\circ}C$ for 100 days were resulted in the highest germination ratio as well as the shortest days for germination. 6. The successive embryo growth during chilling treatment and seed germination were significantly inhibited by immersing seeds in water just before chilling treatment or during chilling treatment and by interruption of chilling treatment with raising temperature to $20^{\circ}C$ for 20 days during chilling treatment. 7. The germination ratio of ginseng seeds which finished chilling treatment was highest at $10^{\circ}C$ and 62.5% was the estimated soil moisture for the best germination of ginseng seeds. The ginseng seeds were found to require high amount of oxygen for germination. 8. Only water soluble material in homogenized ginseng seeds showed a significant inhibiting effect on the seed germination of sesame, millet and soybean. Water soluble material dissolved from undehisced ginseng seeds showed stronger inhibiting effect on the seedling growth of sesame than material from dehisced ginseng seeds. Extraction temperature did not influence the inhibiting effect of the material dissolved from ginseng seeds on the seedling growth of sesame. 9. Water soluble materials dissolved from the berry pulps, leaves, fresh roots and dried roots also showed a significant inhibiting effect on the seedling growth of sesame. 10. Water soluble materials dissolved from the ginseng seeds, leaves and fresh roots showed a significant inhibiting effect on the germination of true fungi and the growth of spawn but the growth of phytopathogenic bacteria was not. 11. Among the water soluble materials dissolved from ginseng seeds, the materials of low molecular weight less than 3,000 were resulted a significant inhibiting effect on the seedling growth of sesame and the materials of high molecular weight also showed an inhibiting effect.

• Korean Journal of Social Welfare
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• v.59 no.1
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• pp.301-327
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• 2007

The purpose of this study is to examine the timing and the risk factors associated with the adoption of legally-free foster children. The sample of the study was drawn from foster care files of Adoption and Foster Care Analysis and Reporting System(AFCARS) in 32 states between October 1998 (FY 1999) and September 2002(FY 2002). The timing post-TPR to adoption was examined by plotting the Kaplan-Meier cumulative hazard function for adoption and by plotting the KM hazard functions stratified by child's race and child's age at TPR. Cox proportional-hazards regression analysis was used to identify risk factors for adoption of legally-free foster children after TPR. The hazard of adoption was very low immediately after TPR but increased steadily starting at 3 months and then declined after 20 months. The cumulative hazard functions for White non-Hispanic children and Black non-Hispanic children crossed over at 13 months after TPR. Racial minority status, older age, and disability were negatively associated with the hazard of adoption. Physical abuse, sexual abuse had the lower hazard for adoption compared by neglect. Caretaker's inability to cope had the slightly lower hazard for adoption whereas inadequate housing showed the slightly greater hazard for adoption. Characteristics of foster care services turned into be powerful predictors of adoption. Specifically, legally-free children placed in pre-adoptive homes, those who shared the same racial/ethnic background with their foster caretakers, and those who were placed in two-parent families have a greater likelihood of adoption. The findings highlight the importance of foster care service provisions after TPR to facilitate adoption of legally-free foster children. Furthermore, a more substantial resources and targeted support for foster children who experience physical abuse and sexual abuse in need of adoption should be provided for moving the foster children into permanency.