Coefficients and terms of the liquid drop model and mass formula

The coefficients of different combinations of terms of the liquid drop model have been determined by a least square fitting procedure to the experimental atomic masses. The nuclear masses can also be reproduced using a Coulomb radius taking into account the increase of the ratio $R\_0/A^{1/3}$ with increasing mass, the fitted surface energy coefficient remaining around 18 MeV

Micro-Drilling of ZTA and ATZ Ceramic Composit: Effect of Cutting Parameters on Surface Roughness

Ceramics are a class of materials widely used during last fifteen years for orthopaedic applications. It is well known that they are characterized by low wear rate, and friction coefficient. However, these materials are very difficult to machine into complex shapes because of their brittleness and high hardness. The most effective method to increase the crack resistance is the formation of a composite structure. This class of materials, composed by two or more different ceramics, can present higher characteristic respect to the single component, like fracture toughness and flexural strength. This paper presents a study of the influence of cutting parameters (cutting speed, feed rate and step number) onto the hole surface roughness and deformation due to the drill operation. The ceramic composite materials AZT (alumina toughened zirconia) and ZTA (zirconia toughened alumina) were first characterized in terms of hardness and roughness. After the drilling test, the holes were analyzed using scanning electron microscope (SEM) and an advanced 3-dimensional non-contact optical profilomete

Worker turnover at the firm level and crowding out of lower educated workers

unemployment;wages;labour turnover. education;business cycles

Separations at the Firm Level

This paper analyzes the determinants of lay-offs, job-to-job movements and total separations with a unique data set that combines information on individual firms and their workers. We are in particular interested in whether the lay-off policy of firms can explain the relatively high level of unemployment amongst lower educated workers and the relatively strong sensitivity of their unemployment rate to the business cycle. We find that lay-off rates decrease with education but that the change over the cycle in the lay-off rate of workers with a lower level of education compared to that of workers with a higher level of education can not explain the stronger cyclicality of the unemployment rate for lower educated workers. We conclude that this stronger cyclicality is not due to the personnel policy of firms.unemployment;mobility;layoffs

Understanding the failure of education for sustainable development:an analysis of the content and pedagogy of education for sustainable development

Abstract. Widespread changes to the social, economic, and natural environments caused by human activities threaten the increase in life quality achieved in the 21st century. This has led to the acknowledgement that a sustainable transition of our societies is required so that the basic human needs of current and future societies are met. The recognition of education as one of the main tools to achieve this transition has led to the creation of education for sustainable development (ESD), which aims at transmitting skills, values, and ethics of sustainability. Although there have been numerous declarations of intention from states and global governing bodies, evidences show a gap between the expressed ambitions and the effectiveness of ESD implementation. One of the main challenges is to switch from an environmental studies-centered approach to ESD, where sustainability competences are merely seen as a collection of learned knowledge and skills, to a holistic educational approach where the entire educational and social structure is devoted to transmitting sustainability skills and values and give opportunities to act sustainably. The aim of this thesis is to 1) understand what is ESD, its relation to sustainable development and to the educational process; 2) identify the obstacles to an efficient implementation of ESD; and 3) define the content and pedagogy of ESD. The intention is to build a content and pedagogical framework that can be used for the implementation of ESD in educational contexts