Determination of the columnar to equiaxed transition in hypoeutectic lamellar cast iron

Shrinkage porosity as a volume change related casting defect in lamellar cast iron was reported in theliterature to form during solidification in connection to the dendrite coherency. The present work includesan experimental study on dendrite coherency – also called columnar-to-equiaxed transition in lamellar castiron using thermal analysis and expansion force measurements. Investigation was carried out in order tostudy the mechanism of dendrite coherency formation. Cylindrical test bars were cast from the same alloywith different pouring temperature, amount of inoculant and time between the addition of inoculant andstart of pouring the samples. Cooling rate and expansion force was recorded as a function of time. Anumerical algorithm based on temperature differences measured under solidification was used to inter-pret the solidification process. Three different methods have been compared to determine the columnarto equiaxed transition. The compared methods were based on registered temperature differences, basedon registered expansion forces during the volume change of the solidifying samples and based on the cal-culated released latent heat of crystallization. The obtained results indicate a considerable influence on theformation and progress of coherency due to variation of casting parameters. It has been shown that thecoherency is not a single event at a defined time moment rather a process progressing during a timeinterval.

Government decentralization and disaster impact, an exploratory study

The purpose of this study is to explore the link between decentralization and the impact of natural disasters through empirical analysis. It addresses the issue of the importance of the role of local government in disaster response through different means of decentralization. By studying data available for 50 countries, it allows to develop the knowledge on the role of national government in setting policy that allows flexibility and decision making at a local level and how this devolution of power influences the outcome of disasters. The study uses Aaron Schneider’s definition and rankings of decentralization, the EM-DAT database to identify the amount of people affected by disasters on average per year as well as World Bank Indicators and the Human Development Index (HDI) to model the role of local decentralization in mitigating disasters. With a multivariate regression it looks at the amount of affected people as explained by fiscal, administrative and political decentralization, government expenses, percentage of urbanization, total population, population density, the HDI and the overall Logistics Performance Indicator (LPI). The main results are that total population, the overall LPI and fiscal decentralization are all significant in relation to the amount of people affected by disasters for the countries and period studied. These findings have implication for government’s policies by indicating that fiscal decentralization by allowing local governments to control a bigger proportion of the countries revenues and expenditures plays a role in reducing the amount of affected people in disasters. This can be explained by the fact that local government understand their own needs better in both disaster prevention and response which helps in taking the proper decisions to mitigate the amount of people affected in a disaster. The reduction in the implication of national government might also play a role in reducing the time of reaction to face a disaster. The main conclusion of this study is that fiscal control by local governments can help reduce the amount of people affected by disasters.