1,720,995 research outputs found
Machine learning for in-process end-point detection in robot-assisted polishing using multiple sensor monitoring
No full textThe decision on polishing operation stopping time when employing a robot-assisted polishing machine is a critical issue for the full automation of the polishing process. In this paper, a machining learning approach based on artificial neural networks was developed using multiple sensor monitoring data to realize an intelligent system capable to determine the state of the polishing process in terms of target surface roughness achievement. During the experimental tests, surface roughness measurements were performed on each polished workpiece and the acquired sensor signals were analyzed and processed by applying two kinds of feature extraction procedures: statistical features extraction and principal component analysis. By feeding diverse types of feature pattern vectors to artificial neural networks, a highly accurate classification of the polishing process state was obtained using the principal component feature pattern vectors
Microbial-based cutting fluids as bio-integration manufacturing solution for green and sustainable machining
No full textMetal working fluids in machining operations, also called cutting fluids (CFs), accomplish the main functions of lubrication between the tool and the work material, cooling down the cutting zone, and washing away the chips from the cutting area. Traditional CFs are either entirely based on mineral oils or, for water-based CFs, contain up to 10% mineral oils. Over time, CFs become contaminated by foreign substances, including bacteria and fungi, causing rancid odour in the work environment and health hazards for the machinists; this contamination is countered by adding biocides, which in turn can be polluting and unhealthy. Conventional CFs, therefore, are potentially pathogenic for humans, deteriogenic for the environment, and costly to dispose of due to the mineral oil and biocide contents. As the global CF consumption amounts to over two million tons/year, the development of greener, more sustainable CFs is highly desired in the manufacturing industry. In this paper, the replacement of mineral oil in CFs with suitable microorganisms providing the lubrication function is studied within a bio-integrated manufacturing approach, with the aim to markedly reduce the negative impact conventional CFs on environment and human health. The turning trials were performed on AISI 1045 steel bars under Small Quantity Lubrication (SQL) conditions using a microbial-based CF containing a microalgae species as lubricant component. The viability and effectiveness of utilising the novel microbial-based CF was positively demonstrated. The cutting forces, tool wear level, surface finish and dimensional accuracy achieved with the microbial-based CF were comparable to or better than for dry cutting and conventional CF
Integration of reverse engineering and ultrasonic non-contact testing procedures for quality assessment of CFRP aeronautical components
No full textUltrasonic evaluation of induction heat treatment applied to thermoplastic matrix CFRP
No full textThermoplastic matrix carbon fibre reinforced polymers (CFRP) are extensively utilized for composites structures in the aerospace and aeronautical industries. Diverse techniques were currently applied to joining composite parts, the most promising method is the induction heat treatment. In this paper, experimental tests were performed on thermoplastic matrix CFRP specimens by varying the induction heat treatment parameters: power, frequency and current. An advanced ultrasonic (UT) non-destructive evaluation based on pulse-echo technique was employed for the investigation of the utilized process parameters through the UT evaluation of the process induced damage and its depth along the thickness of the thermoplastic matrix CFRP laminates
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
- …
