1,721,053 research outputs found
Correction to: Performance measurement for offline inspections under variable interactions and inspection errors in low-volume production
No full textIn the published article “Performance measurement for offline inspections under variable interactions and inspection errors in low-volume production. Prod. Eng. Res. Devel. (2021). https:// doi. org/ 10. 1007/ s11740- 021- 01077-9” the order of author's name is given incorrectly. Erratum: Verna Elisa, Genta Gianfranco, Galetto Maurizio & Franceschini Fiorenzo was the Authors list in the article. Corrige: the correct Authors list should be: Elisa Verna, Gianfranco Genta, Maurizio Galetto & Fiorenzo Franceschini. Erratum: the previous citation of the article was: “Elisa, V., Gianfranco, G., Maurizio, G. et al. Performance measurement for offline inspections under variable interactions and inspection errors in low-volume production. Prod. Eng. Res. Devel. (2021). https:// doi. org/ 10. 1007/ s11740- 021- 01077-9”. Corrige: the article should be cited as “Verna, E., Genta, G., Galetto, M., et al. Performance measurement for offline inspections under variable interactions and inspection errors in low-volume production. Prod. Eng. Res. Devel. (2021). https:// doi. org/ 10. 1007/ s11740- 021- 01077-9”. Original article corrected
Uncertainty evaluation of small wear measurements on complex technological surfaces by machine vision-aided topographical methods
No full textWear assessment is an essential feature within the Industry 4.0 framework to optimise machining and control durability of components made of innovative materials. Complex topographies often make wear measurement a challenging task. Literature tackles it by comparing the final topography with the unworn state, either by empirical methods or by registration via machine vision algorithms. This paper develops a framework to evaluate the related measurement uncertainty, so far lacking, by exploiting instruments metrological characteristics and statistical modelling. This framework is applied to an industrially relevant case study to compare the performances of accredited methods for wear measurement available in literature
Oil whip and unstable whirling in anisotropic rotors on lubricated bearings
No full texthe dynamics of rotors running on lubricated bearings is complex. While the linearized analysis allows to study the stability in the small and phenomena like oil whirl and oil whip, more complex behaviour, that may include chaotic motion, requires a fully nonlinear analysis. Since lubricated bearings behave like anisotropic supports, complex whirling pattern can be expected when the rotor is anisotropic. The aim of the present paper is to investigate to what extent the anisotropy of the rotor affects its dynamic behaviour. In particular, the interactions between the instability ranges due to rotating anisotropy and to oil whip are searched. The rotor models are built using DYNROT FEM code to build the basic rotor model and to obtain linearized solutions. The linear model of the rotor is then mated to nonlinerar bearing models and integrated numerically in time. Time domain results allow to draw some general conclusions applicable to simplified models as well as to real-world rotors
Unbalance response of rotors: a modal approach with some extensions to dumped natural systems
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Accurate estimation of prediction models for operator-induced defects in assembly manufacturing processes
Get PDFThe presence of defects in industrial manufacturing may compromise the final quality and cost of a product. Among all possible defect causes, human errors have significant effects on the performances of assembly systems. Much research has been conducted in recent years focusing on the problem of defect generation in assembly processes, considering the close connection between assembly complexity and human errors. It was observed that the relationship between the average number of defects introduced during each assembly phase and the related assembly complexity follows a power-law relationship. Accordingly, many authors proposed a data logarithmic transformation in order to linearize the mathematical model. However, as has already been discussed in literature, when the model is retransformed in the original form a significant bias may occur, leading to completely wrong predictions. In this paper, the bias due to the logarithmic transformation of models for predicting defects in assembly is analyzed and discussed. Two alternative methods are proposed and compared to overcome this drawback: the use of a bias correction factor to the retransformed fitted values and a power-law nonlinear regression model. The latter has proved to be the best approach to predict defects with few non-repeated data and affected by high variability, such as in the case under study
Going Beyond Counting First Authors in Author Co-citation Analysis
Get PDFThe 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
Get PDF“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
An artificial intelligence classifier for electron beam powder bed fusion as-built surface topographies
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