Population changes of Ad_lie and emperor penguins along the Prince Olav Coast and on the Riiser-Larsen Peninsula

The trends of penguin populations are thought to be reliable indicators of ecosystem changes in the Southern Ocean. There are seven Ad_lie penguin colonies and one emperor penguin colony along the Prince Olav Coast and one emperor penguin colony on the Riiser-Larsen Peninsula. We compiled and analyzed the available data collected by airborne and ground census between 1971 and 2000 in order to determine the breeding status of penguins in this area. Ad_lie penguin populations increased at two colonies; no apparent trends were observed at other colonies. Emperor penguin populations were high in the mid-1990s and suddenly decreased in 2000. Populations need to be carefully monitored in the coming years

Simplified Method to Evaluate Upper Limit Stress Intensity Factor Range of an Inner-Surface Circumferential Crack under Steady State Thermal Striping

Simplified method to evaluate the upper limit stress intensity factor (SIF) range of an inner-surface circumferential crack in a thin- to thick-walled cylinder under steady state thermal striping was considered in this paper. The edges of the cylinder were rotation-restrained and the outer surface was adiabatically insulated. The inner surface of the cylinder was heated by a fluid with constant heat transfer coefficient whose temperature fluctuated sinusoidally at constant amplitude ΔT. By combining our analytical temperature solution for the problem and our semianalytical numerical SIF evaluation method for the crack, we showed that the desired maximum steady state SIF range can be evaluated with an engineering accuracy after ΔT, the mean radius to wall thickness ratio rm/W of the cylinder, the thermal expansion coefficient and Poisson’s ratio are specified. By applying are method, no transient SIF analysis nor sensitivity analysis of the striping frequency on the SIF range is necessary. Numerical results showed that our method is valid for cylinders in a range of rm/W = 10 to 1