1,721,162 research outputs found
Kinematic and Dynamic Study of Cam Mechanisms for Bottling Machines
Full text linkThe main objective of this study is to analyze and optimize the cam mechanisms of the cork capper station currently in use for wine bottling machines. For each machine model considered, current cam profiles and corresponding real trajectories performed during operation are analyzed. Subsequently, various alternative laws of motion are tested to implement the same process, respecting the same precision points but modifying other parts of trajectory to improve machine dynamic performances. A series of tests carried out on a reconfigurable prototype and using different types of cork have made it possible to verify the effectiveness of the new laws of motion and to obtain the load acting on the machine at different operating speeds
INVESTIGATIONS ON THE VISCOMETRIC PROPERTIES OF ETHANE-1,2-DIOL+1,2-DIMETHOXYETHANE BINARY-MIXTURES
No full textThe kinematic viscosity (nu) of pure ethane-1,2-diol (ED), 1,2-dimethoxyethane (DME) and nine binary mixtures at nineteen temperatures ranging from -10 to +80-degrees-C has been measured. The experimental values have been used to test some empirical equations of the type nu = nu(T) and nu = nu(x1), which are also suitable for data fits in the case of strongly associated dipolar components in the mixtures. The chainlike self-association of ED is widely reflected in its viscosity, which is considerably greater than that of DME. The viscosities of all the mixtures increase on passing from the values of pure DME to pure ED as the mole fraction of ED increases, and the mixing process always gives rise to negative excess properties (nu(E)) at all the temperatures investigated. Furthermore, thermodynamic parameters of viscous flow have been evaluated on the basis of Eyring's theory
Design and testing of a digital twin for monitoring and quality assessment of material extrusion process
No full textIn this paper are illustrated conception, realization and validation of an original solution for the digital twin
of a material extrusion 3D printer, the most popular additive manufacturing machine. The system is composed
by three main modules: a core containing the simulation engine, a data interface managing incoming data
and a graphical interface enabling user remote control. It receives as input the process data collected by
several sensors and the same part program (G-Code file) used by the real machine; thus, the system provides
various real time functions for process monitoring, condition monitoring and geometrical accuracy control.
Alongside detecting load on critical components and checking wear and tear, it can also systematically sort
data collected or calculated during operation to help in optimizing printing parameters. Through interaction
with the print host software, the twin is able to intervene directly in the current process to pause printing in
case of anomalies and to assist users along a recovery procedure. An index of quality of the printed piece is
obtained by comparing the CAD model of the printed part and a 3D model of the deposited material powered
by the data coming from the machine. The system has been tested on a custom-made Cartesian printer: a
number of prints were made with different speeds and accelerations to assess the impact of these settings on
the average quality, and a more in-depth study was carried out on the digital models of the prints to investigate
the origin of the defects detected. The programs and devices used do not rely on commercial solutions, so that
the system is easily replicable
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
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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