Fatigue life of electrodischarge drilled Inconel 718

The machining of complex shapes in difficult-to-cut materials is hardly achieved by traditional metal cutting. Particularly small deep holes are often a cause for premature tool failure or even a technological frontier. Yet, the use of Nickel-based alloys is common in high-temperature and aerospace applications, where thin shapes and deep holes are often required. In these cases non-contact processes, such as electrodischarge (ED) drilling, may be the only viable manufacturing solution. Morphology of ED machined surfaces is significantly different than obtained by metal-cutting operation and is known to jeopardize fatigue strength, but the extent needs to be gauged and related to the process parameters. The paper addresses the effect of ED drilled holes (0.8 mm diameter, aspect ratio 10) on the fatigue life of Inconel 718. Rotating bending fatigue tests are executed on specimens drilled under two ED setups, as well as with a traditional cutting tool. Specimens free from holes are fatigued under the same conditions for comparison. Extremal ED parameters are selected based on previous studies: conditions for best surface finish are contrasted with those for highest productivity. S-N curves show that the ED process causes a decrease of the fatigue resistance with respect to traditional drilling, whereas the effect of different ED setups is negligible. Maximum productivity can thus be pursued with no threat to fatigue performance. The fatigue limit variation is quantified by using the superposition effect principle: ED drilling causes an increase of the stress concentration factor around 25% if compared to traditional drilling. The macroscopic fatigue behavior is integrated with a study of the effects of the different drilling processes in the micro-scale, by means of a microstructural and fractographic analysis

The cement of civil society. Polity and Policymaking

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A policy-oriented approach to co-production. The case of homestay accommodation for refugees and asylum seekers

While co-production has become ever more crucial for contemporary public administration, there is no shared understanding on how to identify the co-producers. Drawing on a policy-oriented approach to co-production, this article develops a theoretical framework to identify policy beneficiaries and policy targets by looking at policy goals. Based on this distinction, we shed light on the different role that citizens can play in co-production, i.e., regular producers, clients, volunteers, or citizen producers. To validate this theoretical framework empirically, the article analyses different homestay-accommodation projects for refugees. Our findings will help scholars and practitioners to identify co-producers more accurately

Frēstyl: Simplifying the Process of Promoting and Discovering Local Live Music

In this paper, we present a new service for web and iPhone for promoting and discovering live music, frēstyl. We will show how frēstyl addresses and attempts to solve the problem that emerging musicians, local promoters and small/medium venues face when publicizing their events, both on a local and global level, and the problem that music fans face when trying to gather a complete but not overwhelming understanding of local and global live music events

Precarious Voices? Types of “Political Citizens” and Repertoires of Action among European Youth

This article’s goal is to explore the existence of ‘political citizens’ profiles across three European cities (Turin, Cologne and Lyon) and to ascertain the role of an unstable occupational status on the repertoires of action deployed. For this purpose, a technique called latent class cluster analysis (LCCA) is applied to a large sample, including young precarious and regular workers (deployed as a reference group). This technique allowed us to derive five descriptive probabilistic profiles of ‘political citizens’ and their repertoires of action in each city. The empirical findings underline the emergence of hybrid repertoires of action together with ‘single-issue’ or ‘cause-oriented’ forms of political participation. This study represents an attempt to encourage the dialogue between two strands of research in social sciences, namely sociology of work and political participation and to foster the formation of an innovative research agenda crossing these two fields

Re‐thinking policy and (multi‐level) governance failure: What went wrong and why in the reception of Ukrainian refugees in Italy?

Following the outbreak of the war in Ukraine and the arrival of 170,000 refugees, the already fragile Italian refugee system was forced to undergo major re-structuring and expansion. Re-organisation included the adoption of partially new multi-level governance relationships, as well as political instruments. Despite the widespread positive attitude of public opinion toward the Ukrainian refugees and the bipartisan support for their reception, the outcome of the policy has been not in line with the goals the proponents set out to achieve. In fact, there have been delays, poor assistance to those who have offered to host, and, in the end, a partial waste of the economic and human resources which were devoted to the reception itself. The purpose of this article is to investigate the origin and development of the “vices” of this process, departing from the interpretive lens on policy and governance failure. Our findings consolidate the theoretical challenge to the reductive binary rhetoric on success and failure, and the classic view of failure confined to formulation and implementation. In addition, the article shows that multi-level governance dynamics are strongly relevant in explaining the “vices” of policies, particularly highlighting the role, until now largely disregarded, of the latent conflicts between the actors involved. The study has benefited from 38 semi-structured interviews with political actors, including third-party organisations and public actors, the analysis of political documents, and local and national media