Life Extension of Aged Jointed Plain Concrete Pavement through Remodeling Index-Based Analysis.

As jointed plain concrete pavements (JPCP) age in South Korea, the cost of pavement maintenance is increasing annually. To extend the life of jointed concrete pavements through preventive maintenance, this study used 2017 pavement management system data to analyze the effects of traffic volume, alkali-silica reaction (ASR) grade, age, smoothness, and damaged area on the remodeling index (RMI-a measure of expressway pavement condition). In addition, this study evaluates the final RMI as well as the corresponding pavement condition and change in RMI value after conducting preventive maintenance in lieu of resurfacing or overlaying. The results demonstrated that the effect of ASR grade increased as the RMI forecast year increased and that change in surface distress (△SD) increased with age (most intensively when the pavement was 15-20 years of age). Moreover, change in international roughness index (△IRI) increased with age and traffic volume (similarly within 15-20 years of pavement age). Hence, preventive maintenance is a must for sections with high traffic volume and age even if the RMI is low. Finally, performing repairs through preventive maintenance decreases the number of expressway sections requiring resurfacing and overlaying, thus extending the life of the concrete pavement.

Influence of temperature shifts on the onset and development of red sea bream iridoviral disease in rock bream Oplegnathus fasciatus.

The effects of various water temperature treatments on the development of red sea bream iridovirus disease (RSIVD) in rock bream Oplegnathus fasciatus challenged with iridovirus Sachun (IVS-1) were determined by measuring the mortality and the viral concentration in the spleen of infected fish. Experimental infections of rock bream with IVS-1 at water temperatures of 18, 21, and 25 degrees C resulted in a cumulative mortality of 100%, but infections at 13 degrees C resulted in 0% mortality, even after 45 d. The disease progressed more rapidly at higher water temperatures; at 25, 21, and 18 degrees C, the mean numbers of days until death were 17, 20, and 30 d, respectively. When the water temperature for fish infected with iridovirus by intramuscular injection was shifted from 13 to 25 degrees C, the cumulative mortality reached 100%, with rapid onset of the disease, independent of the time at which the temperature was shifted, i.e. 7, 14, or 30 d after injection at 13 degrees C. Real-time PCR data revealed that the viral genome copy number in the spleen of rock bream maintained at 13 degrees C increased with time, suggesting the occurrence of viral replication even at 13 degrees C. In the reverse experiment, when the water temperature for fish that were infected at a higher temperature was shifted to 13 degrees C, 3 or 7 d after injection at 25 degrees C, the fish showed 100% cumulative mortality, although the mean number of days until death was higher than that observed for fish maintained at a constant temperature of 25 degrees C. The viral DNA concentration in the spleen of rock bream that had been shifted down to 13 degrees C, 3 or 7 d after injection at 25 degrees C, was not suppressed, but increased and eventually reached levels sufficient to induce mortality at 13 degrees C. However, the level of viral genome copy numbers in the spleen of dead fish at 25 degrees C, regardless of whether those fish were held at a constant temperature of 25 degrees C or shifted up from 13 degrees C, appeared to be greater than the level found in the dead fish shifted down to 13 degrees C after inoculation at 25 degrees C.