1,721,024 research outputs found
About enhanced applications of experiment-based full-field datasets in failure risk grading and vibro-acoustics
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Modeling of the dissipative properties of a material by means of a generalized fractional SLS approach
No full textA physically sound material model must satisfy some strict conditions. It must be causal, i.e. strain vs stress frequency response function must be consistent, where is the complex conjugate operator. Moreover, the model should be consistent with experimental results obtained from any homogeneous structure made of the modeled material. Standard material tests range from quasi-static (stress and strain relaxation) to low to high frequency behavior (free and forced vibrations). The dissipative material properties
strongly influence the value of the stress and strain relaxation time and of the damping ratio associated to any natural vibration mode of a tested specimen.
The simplest standard material models known from literature are the Hook, Newton, Maxwell and Kelvin material models, and it will be shown that they are not consistent with the previously outlined conditions. Nevertheless, such simple models can be combined to obtain more effective models [1]. The classic standard linear solid (SLS) model is made up of a series arrangement of Kelvin model blocks ( being the model order) where can be high if many conditions deriving from test measurements must be satisfied. The dissipative behavior of such models depends on the viscosity parameter associated to the viscous elements of each Kelvin block constituting the SLS model, but it will be shown that high viscosity values typically lend to both high relaxation times and overdamped free response too. While the former result is generally consistent with experimental results, the latter result is typically not consistent with tests done with specimens in medium to high frequency vibrational conditions. Newtonian material models with fractional derivative operators were proposed in the past [2]. The dissipative behavior of such models depends on both the viscosity parameter and the associated fractional derivative order, typically allowing to model quasi static and free vibrational behavior of material specimens with a low order generalized fractional SLS model
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
Molecular characterisation of bois noir phytoplasmas from Bosnia and Herzegovina
No full textBois noir (BN) phytoplasmas were associated with grapevine yellows diseases in Bosnia and Herzegovina (Delic and Lolic, 2010). The disease is widely to moderate distributed in vineyards with both domestic and imported grapevine cultivars. Molecular characterisation of selected strains of BN phytoplasmas detected in heavily BN-infected vineyards in was done to verify the presence of genetic variability. Thirty-five DNA samples of grapevines that were shown to be positive by PCR assays on the 16S rDNA were selected for the study. Polymorphisms were studied in the 16S rDNA, Tuf and ribosomal protein genes of the selected samples. Tuf1f/r, TufAYf/r, and TufINT1f/TufINT4r primer pairs were used in nested PCR for amplification of Tuf genes; RFLP analyses with HpaII showed the presence of the tuf type-b (VK-II) in all the tested samples.
The BN infected samples were further amplified with rp/STOL primers and PCR products were digested with TaiI and SspI restriction enzymes. Finally 16S rDNA genes were amplified with P1/P7 primers in direct PCR and with R16F2n/R16R2 primers in nested PCR assays: both types of amplicons obtained were restricted with MboII and RsaI, MboII, Hpy188I enzymes, respectively.
Restriction profiles obtained after RFLP analyses on 16S rDNA and ribosomal protein amplicons weren't uniform. Some samples showed profiles comparable with some of those recently published (Contaldo et al., 2009), while some of the profiles of other samples were totally different from any of those reported in literature. Therefore, polymorphism of these regions should be further studied to better understand BN epidemiology in Bosnia and Herzegovina
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
Dispelling the Myths Behind First-author Citation Counts
Full text linkWe conducted a full-scale evaluative citation analysis study of scholars in the XML research field to explore just how different from each other author rankings resulting from different citation counting methods actually are, and to demonstrate the capability of emerging data and tools on the Web in supporting more realistic citation counting methods. Our results contest some common arguments for the continued
use of first-author citation counts in the evaluation of scholars, such as high correlations between author rankings by first-author citation counts and other citation
counting methods, and high costs of using more realistic citation counting methods that are not well-supported by the ISI databases. It is argued that increasingly available digital full text research papers make it possible for citation analysis studies to go beyond what the ISI databases have directly supported and to employ more
sophisticated methods
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