1,721,032 research outputs found
Self presentation in blogs and social networks
No full textRecent approaches to the study of identity in online contexts underline
how people on the Internet have multiple identities and are at risk of identity
fragmentation. Subjectivities are context-specific, negotiated with other people and
actualized in Self Presentations. The aim of this study is to investigate how social
media users deal with choices regarding their Self Presentation and how different
profiles of the same person relate to one other. Thirty-six users with accounts on
two blog-hosting services and one social network website answered an online
structured interview and elaborated on the different choices of Self Presentation
for each service. Content Results show users accurately and consciously choose
the way they present their Self according to their aims, actual and potential
readership, and the technical possibilities of the media. Answers also show that
people online are conscious of the multiple presentations they enact, and they feel
an underlining sense of unity and coherence, which may be traced back to the
concept of Self
An experimental study on a novel reclaimed rubber compound for fiber-reinforced seismic isolators
No full textClassical rubber seismic isolators reinforced with steel shims are generally large, heavy, and expensive so rarely used for housing buildings. In the last few years, different technologies have been investigated and fiber reinforced elastomeric isolators (FREIs) demonstrated to be a promising option. Only by properly combining a lower cost of raw materials including the manufacturing process and an easier installation process can result in a cost-effective solution. In the present study, novel reclaimed-rubber FREIs reinforced with low cost fabrics were designed and manufactured. A reclaimed compound (RC) has been developed resulting in mechanical properties not significantly different from virgin rubber. Mechanical characterization of the RC showed a typical response of soft compound even if with lower tensile deformation capacity. RC adhesion with polyester and nylon fabrics was investigated in order to prevent debonding between different layers. In this regard recycled-rubber FREIs with polyester and nylon fabrics were manufactured and tested in unbonded configuration. The devices showed promising performance and paved the way for the development of low-cost and environmental-friendly seismic isolators for housing buildings
Laboratory characterization of a reclaimed rubber compound for low-cost elastomeric isolators
No full textAlthough seismic isolation devices are effective in protecting structures during an earthquake, they are generally large, heavy, and expensive, making their application prohibitive for housing buildings. In the last few years, different strategies have been investigated to make seismic isolators cheaper and lighter for housing buildings in developing countries. Lower costs can be obtained at different scales: simplifying the installation process of devices, reducing energy consumption during manufacturing, and using recycled materials. Both weight and cost of isolators could be reduced by adopting flexible reinforcements in place of steel reinforcing plates, also allowing easier installation without bolted connections in unbounded configuration. Costs can be further reduced by replacing natural rubber with a recycled elastomer. It has been demonstrated that trying to give a second life to rubber is challenging, since devulcanization process, capable of breaking chemical bonds between rubber and sulphur, is highly polluting and requires high consumption of energy. In the present work, a recycled compound has been preliminary developed with mechanical properties not significantly lower than virgin rubber. Obtained parameters are satisfactory for use in unbounded isolators with flexible internal reinforcement where internal stresses are significantly reduced. In particular, a novel compound has been properly formulated in order to be lower cost in comparison to traditional one. Mechanical characterization of the material showed excellent properties including shear modulus and hardness similar to those of a soft rubber, even if a reduced ultimate deformation capacity is achieved. Furthermore, rubber adhesion with different fabrics has been investigated. Preliminary results are very promising and pave the way for the development of high-performance and low-cost rubber isolators
Dynamic behaviour in compression and shear of low shape factor rubber blocks
No full textThe attention of the authors is focused on the study of low shape factor rubber blocks, having a low vertical stiffness. Firstly, the behaviour of natural rubber blocks is analysed when they are subjected only to an axial load, and then subjected to axial and shear combined action: in the first case, a model which takes into account the geometric non-linearity is considered, that is a model that considers the shape factor as a function of the current compressive strain; in the second case, the main issue is the influence of the axial load on the horizontal stiffness and on damping. For both cases, the analytical results are compared to the experimental ones. © 2019, Patron Editore S.r.l
Analytical and numerical modelling of shear-link device for seismic energy dissipation in frame structures
No full textWith the continuous development of new supplemental seismic control systems, recent research advancements can be applied to structures located in earthquake-prone zones. Several energy dissipation devices have been conceived and experimentally investigated. However, until a comprehensive design procedure that incorporates all parameters of the control system is formulated, the applications of these devices remain limited. The present study is part of a research project about a particular shear-link (SL) dissipative device. It has been recently introduced for an effective seismic protection of structures, also installed for many real applications, especially in South America. Starting from experimental data, an ABAQUS finite-element nonlinear model of such device is presented. It is suitably tuned to simulate the combined isotropic/kinematic hardening response of the SL device. It also provides a deeper understanding of the overall nonlinear behavior of the device, so as to laid the foundations for a simplified modelling approach the authors propose in the second part of the work. The latter is an approximate analytical model able to predict initial stiffness of the SL device, yielding force, as well as the equivalent damping ratio at large displacement. Alternative models for stiffness are also introduced and compared for complexity and accuracy. The final aim is that of providing a reliable yet simple tool the professionals can use to include SL devices in a fully integrated and manageable design process. The assessment of the accuracy of both analytical and numerical models is based on the available experimental data. The results as well as the involved approximation are presented and discussed
Graphene NanoPlatelet-based coating as thermal protection from high-power radiative fluxes
No full textA major disadvantage of polymer-based composite materials is their poor performance when exposed to relatively high heat flux. At temperatures typically above 300–400 °C, the organic matrix decomposes releasing heat, smoke, and toxic volatiles, jeopardising the composite mechanical performances. The heat flux resistance of composites can be improved by integrating protective coatings on their surface. In the present work, graphene nanoplatelet (GNP) films are employed as thermal barrier coatings (TBCs) to mitigate the thermal degradation of Carbon Fibres Reinforced Plastic (CFRP). The films were bonded onto the heat-exposed surface of CFRP laminates. Laser spot heating tests, with different laser power densities (25–150 kW/m2), were adopted to assess the effectiveness of the coating. The effect of the thickness of the protective layer has been tested too, by changing the number of layers (from 1 to 2 layers). From the results, a significant reduction in the temperatures and damages were observed. Moreover, the damage extension and residual mechanical performances of exposed samples have been assessed as a function of the power density and the protection level. A significant improvement of the post-heat flexural moduli and a significant reduction of the damaged areas have been obtained in laminates protected with high-loaded graphene nanoplatelet films
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Variations on the Author
Full text link“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Appropriate Similarity Measures for Author Cocitation Analysis
Full text linkWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
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