Preparation and characterisation of refractory whiskers and selected alumina composites

A whisker is a common name of single crystalline inorganic fibre of small dimensions, typically 0.5-1 μm in diameter and 20-50 μm in length. Whiskers are mainly used as reinforcement of ceramics. This work describes the synthesis and characterisation of new whisker types. Ti0.33Ta0.33Nb0.33CxN1-x, TiB2, B4C, and LaxCe1-xB6 have been prepared by carbothermal vapour–liquid–solid (CTR-VLS) growth mechanisms in the temperature range 900-1800°C, in argon or nitrogen. Generally, carbon and different suitable oxides were used as whisker precursors. The oxides reacted via a carbothermal reduction process. A halogenide salt was added to form gaseous metal halogenides or oxohalogenides and small amount of a transition metal was added to catalyse the whisker growth. In this mechanism, the whisker constituents are dissolved into the catalyst, in liquid phase, which becomes supersaturated. Then a whisker could nucleate and grow out under continuous feed of constituents. The syntheses of TiC, TiB2, and B4C were followed at ordinary synthesis conditions by means of mass spectrometry (MS), thermogravimetry (TG), differential thermal analysis (DTA) and quenching. The main reaction starting temperatures and reaction time for the different mixtures was revealed, and it was found that the temperature inside the crucible during the reactions was up to 100°C below the furnace set-point, due to endothermic nature of the reactions. Quench experiments showed that whiskers were formed already when reaching the temperature plateau, but the yield increased fast with the holding time and reached a maximum after about 20-30 minutes. Growth models for whisker formation have been proposed. Alumina based composites reinforced by (2-5 vol.%) TiCnano and TiNnano and 25 vol.% of carbide, and boride phases (whiskers and particulates of TiC, TiN, TaC, NbC, (Ti,Ta)C, (Ti,Ta,Nb)C, SiC, TiB2 and B4C) have been prepared by a developed aqueous colloidal processing route followed by hot pressing for 90 min at 1700°C, 28 MPa or SPS sintering for 5 minutes at 1200-1600°C and 75 MPa. Vickers indentation measurements showed that the lowest possible sintering temperature is to prefer from mechanical properties point of view. In the TiNnano composites the fracture mode was typically intergranular, while it was transgranular in the SiCnano composites. The whisker and particulate composites have been compared in terms of e.g. microstructure and mechanical properties. Generally, additions of whiskers yielded higher fracture toughness compared to particulates. Composites of commercially available SiC whiskers showed best mechanical properties with a low spread but all the other whisker phases, especially TiB2, exhibited a great potential as reinforcement materials.

Democracy Reconsidered : Britain, France, Sweden, and the EU

The purpose of this thesis is to investigate whether some positions in democratic theory should be adjusted or abandoned in view of internationalisation; and if adjusted, how. More specifically it pursues three different aims: to evaluate various attempts to explain levels of democracy as consequences of internationalisation; to investigate whether the taking into account of internationalisation reveals any reason to reconsider what democracy is or means; and to suggest normative interpretations that cohere with the adjustments of conceptual and explanatory democratic theory made in the course of meeting the other two aims. When empirical methods are used, the scope of the study is restricted to West European parliamentary democracies and their international affairs. More particularly, the focus is on the making of budget policy in Britain, France, and Sweden after the Second World War, and recent budget policy in the European Union. The aspects of democracy empirically analysed are political autonomy, participation, and deliberation. The material considered includes parliamentary debates, official statistics, economic forecasts, elections manifestos, shadow budgets, general election turnouts, regulations of budget decision-making, and staff numbers in government and parliament budgetary divisions. The study reaches the following conclusions among others. (i) The fact that internationalisation increases the divergence between those who make and those who are affected by decisions is not by itself a democratic problem that calls for political reform. (ii) That international organisations may have authorities delegated to them from democratic states is not sufficient to justify them democratically. Democratisation still needs to be undertaken. (iii) The fear that internationalisation dissolves a social trust necessary for political deliberation within nations seems to be unwarranted. If anything, views argued by others in domestic budgetary debate are taken increasingly serious during internationalisation. (iv) The major difficulty with deliberation seems to be its inability to transcend national boundaries. International deliberation at state level has not evolved in response to internationalisation and it is undeveloped in international institutions. (v) Democratic political autonomy diminishes during internationalisation with regard to income redistribution and policy areas taken over by international organisations, but it seems to increase in public spending. (vi) In the area of budget policy-making there are no signs that governments gain power at the expense of parliaments during internationalisation. (vii) To identify crucial democratic issues in a time of internationalisation and to make room for theoretical virtues like general applicability and normative fruitfulness, democracy may be defined as a kind of politics where as many as possible decide as much as possible.

Muslim Women Managing Women's Shelters : Somaya, the Muslimwoman and Religion as Resource

This article focuses on Sisters’ Shelter Somaya in Sweden, an organization unique in its claim to be a women’s shelter by and for Muslim women, and in its combining of Islamic and secular feminisms. Examining the organization’s self-presentations, the author argues that there is, however, an ongoing shift from an emphasis on its Muslim profile to a dissolution of the very same. Looking into potential loss in the process (for clients, activists, allies, and feminism at large), the analysis draws on current research on anti-Muslim intolerance and normative secularism. The concept of the “Muslim woman” is employed to illustrate the stereotyping that continuously associates Muslim women with “victims” inhabiting shelters rather than capable “managers”. Intersectionality is pointed at as an emic strategy adopted by Somaya to overcome division, but also critically analysed as a consensus-creating signifier that hinders diversity. Thus,the article raises the increasingly important issue of the relationship between religion, gender, and feminism in the post-secular turn, and the author calls for critical self-reflection and creative affirmation in the interaction with heterogeneous others.

Essays on Personnel Economics and Gender Issues

This thesis consists of four self-contained essays in economics. Tournaments and unfair treatment. This paper introduces the negative feelings associated with the perception of being unfairly treated into a tournament model and examines the impact of these perceptions on workers’ efforts and their willingness to work overtime. The effect of unfair treatment on workers’ behavior is ambiguous in the model in that two countervailing effects arise: a negative impulsive effect and a positive strategic effect. The impulsive effect implies that workers react to the perception of being unfairly treated by reducing their level of effort. The strategic effect implies that workers raise this level in order to improve their career opportunities and thereby avoid feeling even more unfairly treated in the future. An empirical test of the model using survey data from a Swedish municipal utility shows that the overall effect is negative. This suggests that employers should consider the negative impulsive effect of unfair treatment on effort and overtime in designing contracts and determining on promotions. Late careers in Sweden between 1970 and 2000. In this essay Swedish workers’ late careers between 1970 and 2000 are studied. The aim is to examine older workers’ career patterns and whether they have changed during this period. For example, is there a difference in career mobility or labor market exiting between cohorts? What affects the late career, and does this differ between cohorts? The analysis shows that between 1970 and 2000 the late careers of Swedish workers comprised of few job changes and consisted more of “trying to keep the job you had in your mid-fifties” than of climbing up the promotion ladder. There are no cohort differences in this pattern. Also a large fraction of the older workers exited the labor market before the normal retirement age of 65. During the 1970s and first part of the 1980s, 56 percent of the older workers made an early exit and the average drop-out age was 63. During the late 1980s and the 1990s the share of old workers who made an early exit had risen to 76 percent and the average drop-out age had dropped to 61.5. Different factors have affected the probabilities of an early exit between 1970 and 2000. For example, skills did affect the risk of exiting the labor market during the 1970s and up to the mid-1980s, but not in the late 1980s or the 1990s. During the first period old workers in the lowest occupations or with the lowest level of education were more likely to exit the labor market than more highly skilled workers. In the second period old workers at all levels of skill had the same probability of leaving the labor market. The growth and survival of establishments: does gender segregation matter? We empirically examine the employment dynamics that arise in Becker’s (1957) model of labor market discrimination. According to the model, firms that employ a large fraction of women will be relatively more profitable due to lower wage costs, and thus enjoy a greater probability of surviving and growing by underselling other firms in the competitive product market. In order to test these implications, we use a unique Swedish matched employer-employee data set. We find that female-dominated establishments do not enjoy any greater probability of surviving and do not grow faster than other establishments. Additionally, we find that integrated establishments, in terms of gender, age and education levels, are more successful than other establishments. Thus, attempts by legislators to integrate firms along all dimensions of diversity may have positive effects on the growth and survival of firms. Risk and overconfidence – Gender differences in financial decision-making as revealed in the TV game-show Jeopardy. We have used unique data from the Swedish version of the TV-show Jeopardy to uncover gender differences in financial decision-making by looking at the contestants’ final wagering strategies. After ruling out empirical best-responses, which do appear in Jeopardy in the US, a simple model is derived to show that risk preferences, the subjective and objective probabilities of answering correctly (individual and group competence), determine wagering strategies. The empirical model shows that, on average, women adopt more conservative and diversified strategies, while men’s strategies aim for the greatest gains. Further, women’s strategies are more responsive to the competence measures, which suggests that they are less overconfident. Together these traits make women more successful players. These results are in line with earlier findings on gender and financial trading.