Moisture Distribution in Partially Saturated Concrete Studied by Impedance Spectroscopy

The moisture content and its spatial distribution has a great influence on the durability properties of concrete structures. Several non-destructive techniques have been used for the determination of the total water content, but moisture distribution is difficult to determine. In this paper impedance spectroscopy is used to study the water distribution in concrete samples with controlled and homogeneously distributed moisture contents. The technique is suitable for the determination of water distribution inside the sample, using the appropriate equivalent circuits. It is shown that using the selected drying procedures there is no change in the solid phase of the samples, although the technique can only be used for the qualitative study of variations in the solid phase when samples are too thick. The results of this work show that for a wide range of concrete percentages of saturation, from full to 18 % saturation, practically all the pores keep at least a thin layer of electrolyte covering their walls, since the capacitance measurement results are practically independent of the saturation degree.

Impedance spectroscopy study of the effect of environmental conditions in the microstructure development of OPC and slag cement mortars

In this work, the microstructure of mortars made with an ordinary Portland cement and slag cement has been studied. These mortars were exposed to four different constant temperature and relative humidity environments during a 180-day period. The microstructure has been studied using impedance spectroscopy, and mercury intrusion porosimetry as a contrast technique. The impedance spectroscopy parameters make it possible to analyze the evolution of the solid fraction formation for the studied mortars and their results are confirmed with those obtained using mercury intrusion porosimetry. The development of the pore network of mortars is affected by the environment. However, slag cement mortars are more influenced by temperature while the relative humidity has a greater influence on the OPC mortars. The results show that slag cement mortars hardened under non-optimal environments have a more refined microstructure than OPC mortars for the studied environmental conditions.

Letter from Benjamin Colman to Edward Wigglesworth about John Leverett, 1728 March 4

Benjamin Colman wrote this letter to Edward Wigglesworth on March 4, 1728; it was sent from Colman, in Boston, to Wigglesworth, in Cambridge. The letter concerns their mutual friend, John Leverett, who had died several years before. It appears that Wigglesworth was charged with writing an epitaph for Leverett and had solicited input from Colman. Colman writes of his great admiration for Leverett, praising his "virtue & piety, wisdom & gravity [...] majesty & authority [...] eye & voice, goodness & courtesie."

Mutual perceptions of Asia and the EU/Europe. Media, elite and public opinion in Singapore and Germany. EU Centre in Singapore Working Paper No. 12, December 2012

In an increasingly interlinked and interdependent world, Europe and Asia are key players. Free trade agreements (FTAs), such as the ones the EU concluded with South Korea and Singapore, are indicative of strong mutual economic interests. It is therefore timely to take a closer look at the mutual perceptions of Asians and Europeans – not only at the governmental and policymaking levels, but also in terms of public opinion and the media. Drawing on data from an extensive research project led by the National Centre for Research on Europe (NCRE), New Zealand, the empirical study in this paper assesses the mutual perceptions of the EU/Europe and Asia, and their respective actors, focusing on two countries – Germany and Singapore. It seeks to do so through an analysis of the data collected from print and broadcast media, interviews with media practitioners, and the findings from public opinion surveys.

The European Union and the United States, before the election: a much deeper mutual understanding. Jean Monnet/Robert Schuman Paper Series Vol. 12 Special, October 2012

From the Introduction. Governor Romney’s statement that President Obama was trying to convert the United States into a European state actually served to point out the need for a much deeper understanding of both entities to make considerable progress in the future. The need for a close alliance is taken for granted. However, the link is riddled with confusion and stereotypes. This relationship is considered a normal fact forged by mutual historical legacies. Hence the frequent signs of awkward behaviour and misunderstandings under the cover of the notion that potential damage will be corrected by the force of the special relationship. If conflicts are detected, both parties are said to be condemned to agree. If a lack of knowledge is detected, it will be modified by accessible means. Mechanisms for an understanding and cooperation are within reach. Therefore, an effective relationship is not utopian. However, there are areas in which much work is needed to strengthen the alliance and correct its shortcomings. There is a need, not only for agreements in economic and political issues, but also for a deeper understanding of the essence of both entities.

Le principe de reconnaissance mutuelle dans la libre prestation de services = The principle of mutual recognition in the free provision of services. Research Papers in Law 2/2009

No abstract.