1,720,964 research outputs found
A new criterion for quality monitoring of pulsed laser spot welding using an infrared sensor - Part 1: the radiation feature as a criterion for quality monitoring
No full textMany manufactured goods use pulsed laser spot welding in joining and weld quality has to be controlled in particular. This paper suggests a criterion for quality monitoring of pulsed laser spot welding of thin metal sheets using a point infrared (IR) sensor. A new radiation feature is derived from a mathematical model and its properties are examined. Weld quality is closely related to temperature profile and there are many cases that can generate the expected weld quality. Change in weld quality should be detected from the variation in temperature profile. Simulation results show that the radiation feature can be used to detect the change in the initial temperature profile. In the experiments, radiation features and weld cross-sections were examined for various welding conditions. Results show that the radiation feature could detect the dimensional variation of the heat-affected zone (HAZ)
Robust in-process monitoring of pulsed laser spot welding using a point infrared sensor
No full textMany manufactured goods employ pulsed laser spot welding in joining and it is important to monitor the weld quality. The weld quality is highly related to the thermal history of the weld and there have been many trials to monitor the quality using an infrared (IR) sensor. Though the emitted thermal radiation is a function of the emissivity and the surface temperature, the measuring condition has an important influence on the detectable radiation. To increase the reliability of monitoring, it is useful to find the robust feature that is immune to the change of measuring condition. This paper suggests an in-process monitoring method using a point IR sensor for the pulsed laser spot welding of thin metal sheet. The suggested monitoring method is robust to the change of the measuring condition and it can detect the variation of the absorbed energy as well as any serious defect in the weldment
Current treatment for Alzheimer's disease : an overview
No full textDespite extensive research, no cure has been found for Alzheimer's disease as yet. A large number of medications have been investigated to determine their potential for altering the natural history of the disease and this work is ongoing. In an effort to shed light on current and future (awaiting approval) medications, the following is a summary of published material and experiences with some of the drugs
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
Design of high precision linear stage with double-sided multi-segmented trapezoidal magnet array and its compensations for force ripples
No full textGenerally, linear motor is used as actuators for high precision stage which requires long stroke, high speed and high precision capability. In order to meet the needs of high speed and high precision, it is important that the motor generates large force and has small size. In this paper we propose a linear motor with multi-segmented (MST) magnet array to maximize actuating force per unit volume. The MST magnet array is a modified version of standard Halbach magnet array. Each magnet in the MST magnet array has various shapes and dimensions while standard Halbach magnet array has identical magnets. In order to optimize the shapes and dimensions, design optimization of the motor is carried out and its performance is investigated. We conclude that the linear motor with the MST array can generate more actuating force per unit volume than the one with conventional magnet array and standard Halbach magnet array. A high precision stage is constructed using the optimized MST magnet array. Even though we obtain maximized actuating force, the flux density by the MST array is seriously distorted from ideal sinusoidal flux density with respect to mover position. This distorted flux density results in force ripples when we use three phase commutation. And no matter how small force ripples would be, serious tracking errors occur in high precision linear stages. Thus, force ripple must be compensated. In this paper, we proposed a simple method to reduce the ripple by current shaping. (C) 2006 Elsevier Ltd. All rights reserved
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