1,720,965 research outputs found
Thermoelastic Stress Analysis of the Contact Between a Flat Plate and a Cylinder
No full textIn the frame of intercomparison testing among different optical full-field measurement techniques, the crucial aspect concerning contact problems between bodies has been extensively analyzed through thermoelasticity. This technique has allowed us to obtain stress patterns in terms of the first stress invariant by measuring temperature fluctuation on the surface of a cyclically loaded mechanical component. For the present study, a special-purpose test bench was assembled to be used within a round robin test, so as to properly load the sample. The test case taken into account is the very well-known contact problem between a cylinder and a flat plate. The results obtained from thermoelasticity through the use of a zoom lens, were compared to classical Hertz theory prediction and FEA models
Design of an optical measurement system for dynamic testing of electrospindles
No full textDynamic characterization of electrospindles is necessary to ensure long life, reliability and high-tech performance required in many industrial applications. Many diagnostic approaches have been developed with regard to fault detection and dynamic characterization of rotating machinery.
Here, an optimized set-up of a measurement system based on electro-optical sensors is proposed for performing vibration tests on electrospindle rotors. A complete, dynamic characterization of the rotor is obtained through modelling and accurate measurements of shaft vibrations are performed to trace vibration modes of the rotor. The proposed measurement set-up can be used to support the design optimization of electrospindles in order to increase quality standards
Development of a new capacitive matrix for a steering wheel's pressure distribution measurement
No full textPressure distribution measurements are becoming increasingly important in the automotive field for ergonomic optimization of components like seats or steering wheel. Nowadays, traditional sensors shows several drawbacks such as response variation in time, low sensitivity and high level of intrusiveness. Moreover the great difficulty of carrying out dynamical analysis in the area of interest highly limits their use. A new type of matrix, now available, promises to overcome such problems, and it has been widely tested in the automotive field. The matrix is based on a series of condensers which vary the capacity depending on the pressure applied on their surface. The high sensitivity and the chance of monitoring pressure distribution with frequency contents up to 200 Hz make this tool particularly suitable for evaluating steering wheel’s goodness effectiveness in an on-road test. Relevance to industry: The knowledge of the behavior of capacitive sensor matrix for pressure distribution at the operator’s hand-car stirling wheel interface may benefit automobile designers and manufacturers to evaluate steering wheel goodness and seat effectiveness perform through on-road tests and to evaluate the efficiency of the power steering mechanism
A Novel Method for the design of prostheses based on Thermoelastic Stress Analysis and Finite Element Analysis
No full textApplied statistics for extreme wind estimate
No full textThe assessment of extreme wind speeds is a crucial issue for securing structural safety of wind turbines and inquiring largest loads to which turbines must be prepared to undergo. International standards suggest applying the Gumbel method of fitting the annual maxima to their theoretic probability distribution. Yet, often, wind databases are too short to apply such methods with statistical significance, and other procedures are commonly adopted [such as peaks over threshold (POT) and independent storms], which involve dependency on arbitrary thresholds for filtering data and issues of sub-asymptocity, i.e. how well the selected dataset fits to density functions describing the distribution of peaks or extreme values. The present paper aims at contributing to such currently ongoing debate, providing a statistical analysis of the application of POT and independent storms methods on wind time series of various lengths from different geographical areas. The CERN data analysis framework ROOT has been employed for guaranteeing excellent standards of computational precision and wealth of statistical information. Analysis of uncertainties in the wind speeds estimates and tests of the goodness of fit of the datasets to the proper distributions have been carried on. An algorithm for choosing the optimum thresholds was developed, which encapsules and compromises the statistical complexity of the methods. A declustering procedure has been carried on for discriminating proper peaks in the POT method: it has been tested that such declustering provides a dramatic improvement of the statistical quality of the method
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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