The Influence of Temperature on the Low-Velocity Impact Response of Polyamide 6/Basalt Plain Fabric Laminates

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Effect of friction on a crashworthiness test of flat composite plates

The diffusion of fiber reinforced plastics in crashworthiness applications is continuously growing thanks to the excellent balance between high mechanical performances and low weight, resulting in most cases in a Specific Energy Absorption (SEA) of composite structures higher than that of the corresponding metallic structures. In this paper, a new fixture to test composite plates applying an in-plane load has been used to investigate the effect of the impact velocity and of the friction caused by the fixture on the SEA of carbon fiber reinforced epoxy plates. The tests have been carried out using a drop tower testing machine and the effect of the friction has been studied varying the clamping force given by the fixture. Splaying is the main failure mechanism found in the specimens during the tests; SEA values (43.6 kJ/kg in average) increase with the clamping force due to the higher friction level induced by higher clamping force; impact velocity does not significantly influence the results. To avoid an overestimation of the SEA due to the excessive friction force (+5.6% when the clamping force increases from 0.8 kN to 8 kN), a Polytetrafluoroethylene (PTFE) coating has been applied to the anti-buckling supports to reduce the friction. The effect of this modification has been studied by carrying out a new test in which the specimen slides between the anti-buckling supports with a given clamping force. A significant reduction (-48% with same clamping force) of the friction force is obtained when the lubricant is applied

Bootstrapping and Collaboratively Enriching the Italian Domain WordNet through the WiKyoto Knowledge Editor

Enhancing the development of multilingual resources is of utmost importance for use in computer applications. The need of ever growing resources for effective multilingual content processing has given impulse to a radical change in the perspective of language resource (LR) creation, structuring, exploitation and maintenance. The Web has played a key role in this process: indeed the possibility to access growing amounts of structured and unstructured data as well as the ease of creating and sharing contents between distributed communities of users have strongly affected the methodologies and techniques to bootstrap, enrich and access LRs. From static knowledge bases usually created and maintained by groups of experts and tailored to the specific exploitation contexts, LRs have turned into dynamic repositories of linguistic knowledge. Their content is usually easily accessible over the Web and often exploited, aggregated and optimized on-the-fly by on-line information mining services. In this context, the adoption of standardized data formats to facilitate interoperability and data exchange is essential. Moreover, the creation and maintenance of these resources has taken great advantage from the possibility to harvest Web data in order to bootstrap or enrich them. Several new frameworks have been proposed to support access, search, integration and interoperability of "new generation" LRs. Wide distributed communities of Web users are more and more directly or indirectly involved in keeping language resources updated or in extending them. After a brief description of modern LRs, we focus our attention on two essential issues involving them: the need for standard formats that support interoperability in a distributed Web context and the possibility for the Web communities to collaboratively maintain and enrich these resources. In particular, we present the Italian WordNet (IWN) and its exploitation in the context of the KYOTO Project, as a real-world scenario where standardization, interlinking, enrichment as well as collaborative editing are put into practice. The KYOTO Project is a complex knowledge-driven environment built with the aim of enabling communities of users to mine information form textual documents, sharing the collected facts across cultures, languages and domains. The semantic ground supporting all the information mining tasks of KYOTO is constituted by the Multilingual Knowledge Base, composed by a collection of WordNets encoding language-specific lexical patterns for each language covered by KYOTO. All of them are mapped to the language-independent entities of the KYOTO Central Ontology. In the context of KYOTO, we describe the process followed to define WordNet-LMF (WN-LMF), the standard format tailored to represent lexical resources adhering to the lexical knowledge WordNet model, useful to easily integrate general and domain lexicons in KYOTO. We present the conversion of the IWN to the WN-LMF standard, as a necessary pre-requisite for IWN to be integrated in the Multilingual Knowledge Base. We expose a (semi)-automatic procedure which allows IWN to upgrade ILI connections to the last version available of the Princeton English WordNet, 3.0. We also consider the Species2000 SKOS thesaurus, a knowledge resource with a data structure different from WordNet: we present its conversion to WN-LMF. To enable the multilingual and multicultural community of KYOTO users to maintain and extend KYOTO knowledge resources, we introduce the Wikyoto Knowledge Editor: it is the Web-based wiki environment useful to navigate, collaboratively enrich the Multilingual Knowledge Base. We describe its Web interface by a practical use case concerning the extension of the Italian Domain WordNet

Contextualizing Microcredit in Bosnia-Herzegovina and Hungary: A Focus Group Exploration

Microfinance is gaining importance as a tool to reduce poverty and promote financial and social inclusion. The main goal of the paper is to analyze the role of microcredit in solving the problem of credit access to vulnerable people. The paper focuses on the direct experience of people who have used microcredit living in Bosnia-Herzegovina and Hungary to analyze the use of microcredit in these areas. From the methodological point of view, the research uses focus groups to investigate customer relations with the banking system, microcredit, social and financial exclusion, and possible alternatives to microcredit. In this way, it is possible to analyze the mechanism through which involvement in microcredit operations results in positive(and negative) effects on people's lives. Results show that microcredit is a great opportunity to facilitate employment, create jobs, increase productivity, improve living conditions promote social integration. Results show that services of mentoring and coaching improve entrepreneurship skills or vocational(technical) know-how. These services help to improve access to finance for vulnerable individuals and to support better living conditions. We identify current good practices among microfinance services to understand the future potential role of microcredit proposes concrete in particular areas

High availability using virtualization - 3RC

High availability has always been one of the main problems for a data center. Till now high availability was achieved by host per host redundancy, a highly expensive method in terms of hardware and human costs. A new approach to the problem can be offered by virtualization. Using virtualization, it is possible to achieve a redundancy system for all the services running on a data center. This new approach to high availability allows the running virtual machines to be distributed over a small number of servers, by exploiting the features of the virtualization layer: start, stop and move virtual machines between physical hosts. The 3RC system is based on a finite state machine, providing the possibility to restart each virtual machine over any physical host, or reinstall it from scratch. A complete infrastructure has been developed to install operating system and middleware in a few minutes. To virtualize the main servers of a data center, a new procedure has been developed to migrate physical to virtual hosts. The whole Grid data center SNS-PISA is running at the moment in virtual environment under the high availability system.Comment: 10 page

An innovative fixture for testing the crashworthiness of composite materials

Despite the growing diffusion of composite materials in automotive and aerospace sectors, a standard procedure for testing their crashworthiness has not been developed yet. At present, the international standards for testing composite materials under impact conditions are not adequate to test their crush behavior. In this paper, a procedure for measuring the energy absorption due to the compressive crushing of a composite flat specimen along its mid plane is proposed. The experimental setup requires a fixture to hold the specimen and to avoid its buckling and an instrumented drop weight tower to obtain the force-displacement curves with the aim of calculating the Specific Energy Absorption. The paper describes the adopted test procedure and some of the features of the newly developed experimental setup. The effectiveness of the procedure is demonstrated by testing several glass fiber-epoxy specimens under different impact energies