471 resultados para stabilisation
Resumo:
A method using iodine has been developed for the stabilisation of low softening point (SP) pitch fibres that avoids air stabilisation in the production of carbon fibres (CF). The interaction between iodine and petroleum pitches has been studied by following the changes in the hydrogen content, aromatic or aliphatic, during the heat treatment of iodine-treated pitch fibres. Two low SP petroleum pitches were used and the iodine-treated pitch fibres were analysed by TGA, DSC, DRIFT, XPS and SEM. The results confirm that using this novel method pitches with low SP can be used to prepare CF with two advantages, compared with conventional methods. The stabilisation time is considerably reduced and treatments to increase the SP, usually required when low SP pitches are used to prepare CF, can be avoided.
Resumo:
The stabilisation of pitch fibres (PFs) is the most important step for their subsequent use in the preparation of carbon fibres (CFs) and their resulting characteristics. The present work studies the influence that the stabilisation time has on the porosity of the CFs, and on the subsequent properties as carbon molecular sieve (CMS). The increase of the stabilisation time carried out at 573 K, from 2 to 8 h favours their CMS properties producing a decrease in the microposity accessible to N2, which gets completely blocked after 6 and 8 h, while the narrow microporosity (V-DR CO2) remains accessible. Adsorption kinetic studies with CH4 and CO2 were performed to assess the possibility of using these CFs as CMS by comparing them with Takeda 3A CMS. The results suggest that there is an optimal stabilisation time which allows the preparation of CFs from an abundant raw precursor with properties similar to Takeda 3A CMS.
Resumo:
This paper argues that it should be possible to complement Europe’s Economic and Monetary Union with an insurance-type shock absorption mechanism to increase the resilience of member countries to economic shocks and reduce output volatility. Such a mechanism would neither require the establishment of a central authority, nor would it lead to permanent transfers between countries. For this mechanism to become a reality, however, it would be necessary to overcome certain technical problems linked to the difficulty of anticipating correctly the position of an economy in the business cycle.
Resumo:
After winning the 2010 presidential election, Viktor Yanukovych and his government developed an ambitious and comprehensive programme of reforms across key areas of social and political life. The return to a presidential system of government created the ideal conditions for the introduction of deep reforms: it allowed Viktor Yanukovych to consolidate more power than any other Ukrainian president before him.The authorities launched an overhaul of the tax and the pension systems, and of the Ukrainian gas sector. Kyiv also completed its negotiations on an Association Agreement with the EU and on a Deep and Comprehensive Free Trade Area. However, the reformist zeal of Ukraine’s political elite progressively diminished as the parliamentary election approached, the economy slowed down, and the polls showed a decline in support for the ruling Party of Regions. Many of the reforms still remain in the planning stages, and in many areas the government has moved backwards. Viktor Yanukovych has proved unable to make systemic changes, and has increasingly used his powers to crush political opposition in Ukraine. The outcome of the latest parliamentary elections prevents the formation of a stable parliamentary majority, which in turn, removes any chance of reform before the 2015 presidential ballot.
Resumo:
The situation in the North Caucasus has stabilised, in comparison with previous years, mainly as regards the activity of the Islamic military underground. This is an effect of ideological changes among the militants which have led to a dilution of the Caucasian armed struggle and its marginalisation in global jihad, since top priority has been granted to the Middle Eastern front. The factors which have contributed to this stabilisation are the organisational crisis in the Caucasus Emirate and the outflux of militants to the Middle East, as well the successful ‘carrot and stick’ policy adopted by Moscow. However, the partial stabilisation in the Caucasus is inherently precarious, being a contingent outcome of the situation rather than the result of systemic change. The region’s pressing problems remain unresolved; and these problems are generating chronic instability and cauing the Caucasus to drift away from Russia in civilisational terms. An economic or political crisis in the Russian Federation may result in the conflicts in the Caucasus unfreezing, including a reactivation of the idea of Chechen independence as well as the idea of the Caucasus Emirate, which is a part of global jihad.
Resumo:
On 15 February 2016 Bosnia and Herzegovina applied for membership of the European Union. This was the result of the new policy strategy which the EU introduced in 2014, aimed at unblocking BiH’s integration process and encouraging local elites to accelerate the reform process. Despite a formal application to the EU, the main internal problems of BiH remain the same - local politicians focus more on the power struggle and enhancing ethnic division than on reform and this is hampering the economic development of one of the poorest countries in Europe. For these reasons this report is devoted to analysing the internal challenges to the stability, coherence and unity of the country. Special attention was also placed on examining the interest and strategies of the various international actors since they can hinder or support the reform process.