The Influence of Extended Cure on Mechanical Performance of Aerospace-Grade Film Adhesives

Bonded adhesive joints have seen increased usage in aircraft structures as weight and cost reductions drive manufacturers to composite designs. As the use of epoxy film adhesives become more prevalent, it is important to characterize the thermal and mechanical properties of the adhesive after exposure to various manufacturing conditions. Prior studies suggest that thermal characteristics and mechanical performance of epoxy resin formulations may be considered a function of chemical structure, cure temperature, and cure duration. It was therefore hypothesized that by controlling cure temperature and duration, the Tg, degree of cure, and mechanical performance of aerospace-grade film adhesives may be controlled. Three epoxy film adhesives cured with three different cure cycles were thermally characterized using DSC, DMA, and rheological techniques. It was shown that increased cure duration provided increased degrees of cure and Tg of the adhesives as a result of a more developed polymer network. V-notch shear and flat-wise tensile testing at ambient dry and elevated temperature wet conditions were used to mechanically characterize the performance of the adhesives cured with three different cure cycles. Mechanical test results showed that adhesives with more aromatic chemical structures saw less degradation as a result of moisture exposure and elevated temperature testing, while the adhesive with simpler chemical structure exhibited significantly reduced performance at elevated temperature wet conditions. It was concluded that while extended cure exposure did not provide significant gains in mechanical performance, the increased polymer network development provided increased resistance to the effects of moisture absorption and elevated temperature environments

The Globality of Islam: Sharia as a Nigerian 'Self-Determination' Movement

This paper was produced as part of a project at the University of California, Santa Cruz titled Globalization, State Capacity and Islamic Movements. The objective of this paper to assess how globalization and Islam impact the capacity of national states to manage Muslim demands for self-determination expressed either as a call for establishing an Islamic state, an alternative Islamic project or greater regional autonomy. After discussing our general arguments, we turn to an analysis of the Sharia movement for self determination in twelve states located in northern Nigeria, a movement that challenged national identities, provoked inter-communal conflict and threatened the existence of the Nigerian federation.

Embodied cognition and temporally extended agency

According to radical versions of embodied cognition, human cognition and agency should be explained without the ascription of representational mental states. According to a standard reply, accounts of embodied cognition can explain only instances of cognition and agency that are not “representation-hungry”. Two main types of such representation-hungry phenomena have been discussed: cognition about “the absent” and about “the abstract”. Proponents of representationalism have maintained that a satisfactory account of such phenomena requires the ascription of mental representations. Opponents have denied this. I will argue that there is another important representation-hungry phenomenon that has been overlooked in this debate: temporally extended planning agency. In particular, I will argue that it is very difficult to see how planning agency can be explained without the ascription of mental representations, even if we grant, for the sake of argument, that cognition about the absent and abstract can. We will see that this is a serious challenge for the radical as well as the more modest anti-representationalist versions of embodied cognition, and we will see that modest anti-representationalism is an unstable position

Financial Integration and Fiscal Policy Efficiency in a Monetary Union.

The gap between the interest rates of different members of the European Monetary Union (EMU) points out to an imperfect degree of financial integration despite the common currency. This paper develops a two-country New Open Economy Macroeconomics (NOEM) model with imperfect financial integration in a monetary union in order to analyze fiscal policy efficiency and the impact of financial integration on the international transmission of fiscal policy shocks. For this, we introduce imperfect financial integration into the fixed exchange rate version of Obstfeld-Rogoff (1995, 1996). We show that a higher degree of financial integration decreases short run consumption and interest rate volatility in both countries while it increases the volatility in the long run following a balanced-budget increase in government spending in one of the countries. In terms of welfare, the degree of financial integration is irrelevant since it has no effect on the utility of the members.New open economy macroeconomics, fiscal policy, financial integration, monetary union.