Investigation of Corrosion Mechanisms of Coated and Uncoated Magnesium Alloys

The corrosion-driven organic coating failure of Mg alloys and in particular the E717 alloy was investigated using a combination of in-situ Scanning Kelvin Probe (SKP) analysis and time-lapse photography where two principal failure mechanisms were identified: cathodic delamination and filiform corrosion. Initiation of underfilm corrosion by application of group I chloride salt to a coating defect produced a cathodic-driven coating delamination. The delamination distance increased linearly with time and the delamination occurred both in the presence and absence of oxygen. Post-corrosion elemental analysis of the delaminated regions using secondary-ion mass spectrometry revealed an abundance of group I cation, but no chloride. Experiments using the SKP and Stratmann-type Mg samples showed that the delamination rates remained linear even at protracted holding times and were insensitive to the type of group I cation present in the initiating electrolyte. Additional experiments on AZ31 and AZ91 Mg alloys revealed that both alloys are susceptible to organic coating delamination with the latter alloy being the most resistant to coating deadhesion. The mechanism was discussed in terms of anodic dissolution at the defect coupled predominantly with underfilm hydrogen evolution, producing organic coating disbondment under conditions where cations are able to transport ionic current within a region of increased pH. The second focus of this thesis was to study the filiform corrosion (FFC) of organic coated E717, AZ31 and AZ91 Mg alloys. The FFC was inoculated by applying MgCl2, HCl and FeCl2 in a coating defect and the FFC propagation rates were quantified by determining the underfilm corroded area with time, which were shown to increase as a function of log[Cl-], remain unaffected by the absence of oxygen, but strongly dependent on the relative humidity of the holding environment. SEM-EDX surface analysis of FFC affected regions was used in combination with in-situ SKP mapping to elucidate the mechanism of FFC propagation, where chloride-induced anodic dissolution at the disbondment front is coupled with the reduction of water on a cathodically activated corroded surface behind with progressive Cl- entrapment in the FFC tail. Finally, the localised corrosion behaviour of the E717 Mg alloy immersed in chloride-containing electrolytes was investigated using an in-situ Scanning Vibrating Electrode Technique (SVET) coupled with Time-lapse Imaging (TLI). The localised corrosion was characterised by discrete local anodes corresponding with the leading edges of dark filiform-like features that combine with time to produce a mobile anodic front leaving a cathodically activated corroded surface behind similar to what was observed with the FFC mechanism. Breakdown potential, measured using time-dependent free corrosion potential transients and potentiodynamic polarisation at neutral and high alkalinity respectively, were shown to vary with the log[Cl-] and the time for corrosion initiation was progressively decreased with increasing chloride concentration

Protest-Case Analysis: A Methodological Approach for the Study of Grassroots Environmental Mobilizations

http://deepblue.lib.umich.edu/bitstream/2027.42/51334/1/570.pd

Proletarianization Under Tourism: A Micro-Level Analysis

http://deepblue.lib.umich.edu/bitstream/2027.42/51093/1/325.pd

Alternative Forms of Resilience. A typology of approaches for the study of Citizen Collective Responses in Hard Economic Times

A variety of theoretical and conceptual perspectives have been applied to studying collective citizen initiatives arising in response to hard economic times, such as solidarity-based exchanges and networks, cooperative structures, barter clubs, credit unions, ethical banks, time banks, alternative social currency, citizens' self-help groups, neighbourhood assemblies and social enterprises. Since the global financial crisis of 2008, scholarly attention on novel, alternative, resilient structures has increased, especially in regions that have been most affected. A comprehensive literature review is therefore needed on these initiatives which usually aim to meet basic needs such as food, shelter, health and education at the community level, or build and envision autonomous communities. This paper has four aims. First, it proposes a new, all-encompassing conceptual framework, alternative forms of resilience, to embrace all issues and groups related to such initiatives, during the new millennium and its economic and political challenges, while taking into account the impact of the 2008 crisis. Secondly, it offers a comprehensive literature review on collective citizen initiatives studied through different theoretical, methodological and conceptual understandings. Thirdly, it provides a new typology of several approaches on novel, collective and solidarity-oriented critical resilience initiatives which take into account political issues, be they policy or social-movement related. Finally, it points to future research areas which would aim to systematically address the political and non-political features of citizen-collective responses

Phosphorescent-based pavements for counteracting urban overheating – A proof of concept

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An analysis of the determining factors of fuel poverty among students living in the private-rented sector in Europe and its impact on their well-being

Existing research suggests that students are an under-reported and under-supported group of the population that frequently lives in fuel poverty. Furthermore, studies show that students do not realize that they live in fuel poor conditions and are rarely recognized as a group vulnerable to fuel poverty. The aim of the research presented in this paper is to understand, evaluate and consequently reveal the experiences of students living in the private-rentedd sector, quantify their possible exposure to fuel poverty, and to determine the impacts of this exposure on their well-being. Three thousand five hundred and twelve students from seven European countries participated in this research making it the largest study to date targeting this specific social group. Our results demonstrate that this group is vulnerable to fuel poverty and that their exposure to such conditions can have a detrimental effect on both their mental and physical health, as well as their social life

Transnational Solidarity, Migration, and the Refugee Crisis: (In)Formal Organising and Political Environments in Greece, Germany, and Denmark

Over the last decade, the unprecedented influx of refugees and migrants into the European Union has posed a significant challenge to Europe, with solidarity being contested at two fronts: first, the question of solidarity with refugees in terms of meeting adequate measures of protection and satisfying their elementary needs; and second, the question of solidarity within the European Union in terms of sharing the costs and burden of hosting these refugees among the member states. One driving factor of these contestations is that the solidarity challenge in facing the ‘refugee crisis’ is taken up differently in transit countries in the South of Europe and destination countries in the North. Wishing to shed light on how national contexts impact transnational solidarity organising, we draw on a fresh set of cross-national evidence from a random sample of 277 transnational solidarity organisations (TSOs) in Greece, Germany, and Denmark. The aim is to illustrate the effects of political opportunities and threats during the 2007–2016 crises period on migration-related solidarity activities organised by TSOs. We will do so through tri-national comparisons tracing the patterns in which migration-related TSOs appear through time. The data used is produced in the context of the TRANSSOL project by a new methodological approach (action organisation analysis) based on hubs-retrieved organisational websites and their subsequent content analysis

Corrigendum to “Pollen-based paleoenvironmental and paleoclimatic change at Lake Ohrid (south-eastern Europe) during the past 500 ka” published in Biogeosciences, 13, 1423–1437, 2016

In this corrigendum we report an updated pollen record from the Lake Ohrid DEEP site spanning the past 500 ka whereby we have reprocessed and re-analyzed 104 samples affected by chemical procedure problems that occurred in one palynological laboratory. Firstly, these samples were affected by the use of wrong containers, causing in- adequate settling of particles at the set centrifuging speed. Secondly, HCl and HF treatments were combined without the prescribed intermediate centrifuging and decanting steps. The inaccuracy in the protocol resulted in the loss of smaller pollen grains and in the overrepresentation of bisaccate ones in most of the re-analyzed samples. We therefore provide an updated set of figures with the new data and have revised the description of the results, discussion and conclusions re- ported in Sadori et al. (2016) where necessary. We stress that the majority of the original results and conclusions remain valid, while the records’ reliability and resolution have improved as 12 samples that had been omitted in the original study because of low count sums are now included in the revised dataset (Sadori et al., 2018)

Civil Society Activism in Italy Across Different Fields: A Multifaceted Picture of Solidarity in Hard Times

Over the last years, Italian civil society organisations have been working on a daily basis to mitigate the impact of both the global economic crisis and the refugee crisis, which have increased social vulnerabilities. Relying on the data gathered through 30 in-depth interviews with transnational solidarity organisations’ representatives, this chapter analyses solidarity practices in three fields of activity: disability, unemployment and migration. Results show that solidarity attitudes, practices and discourses are strongly influenced by the policy domain in which the organisations are active. Furthermore, the crisis led organisations to search for new strategies and approaches, even though it has been an ineffective vector of transnationalisation due to lack of resources, and the necessity to cope with pressing needs at national and local level/s.Results presented in book have been obtained through the project ‘European paths to transnational solidarity at times of crisis: Conditions, forms, role-models and policy responses’ (TransSOL). This project was funded by the European Commission under the Horizon 2020 research and innovation programme (grant agreement No. 649435)