1,721,107 research outputs found
A proposal to modify the Kelly-Tyson equation to calculate the interfacial shear strength (IFSS) of composites with low aspect ratio fibers
No full textThe mechanical behavior of short-fiber composites generally differs from long-fiber composites. The mechanical response is influenced by the particular distribution of tensions and by the mechanism of load transfer from the matrix to the fibers. The transfer load from the matrix to the fibers occurs through shear stresses at the surfaces of the fibers (edges or ends effects). The end effects in long fiber composites, involving a small portion of fiber, are negligible; nevertheless, for short and very short fibers composites these end effects cannot be neglected. Interfacial adhesion between the reinforcement and the matrix plays an important role, in fact it influences both physical and mechanical properties of the composites, but the experimental determination is often laborious and analytical models are frequently used to evaluate the interfacial shear strength (IFSS). In this paper a modification of the Kelly-Tyson model for the calculation of the interfacial stress for short (aspect ratio < 20) and ultra-short fibers composites (aspect ratio < 10) has been proposed to take into account the end effects that in the original model were not considered. Successively, the Bader and Bowyer model (that derives from the Kelly-Tyson model) for the evaluation of the IFSS was also modified. A few examples of calculations of the IFSS, using this modified Bader and Bowyer model, have been provided using published literature data. Furthermore, a mechanical characterization of flax fibers has been carried out and their adhesion to poly(lactic) acid (PLA) matrix were evaluated for composites containing ultrashort fibers (aspect ratio < 10). The IFSS value obtained was compared with that obtained from the single fiber fragmentation test (SFFT). It was found that a very good estimation of IFSS can be done by using this analytical model that can be easily applied with a limited number of experimental tests
An electronic barrier system to improve blood transfusion safety
No full textIn blood transfusion procedures, it is necessary to guarantee that each patient actually receives the blood unit which has been assigned to him, so that mistransfusions are avoided. For this reason, before starting the administration, a cross-check involving the patient and the trasfusion unit codes must be carried out at bedside. To perform these tests in a safe and fast way, several electronic solutions based on barcode labels and RFID tags have been adopted in the last few years. However, most reliable results are still obtained by means of barrier systems, i.e. mechanical devices that prevent the use of units until the cross-check is positive. In this paper, we present a microcontroller-based barrier system which can easily be integrated with common barcode/RFID-based solutions, so that an even higher safety degree is achievable together with simple and fast utilization. The system provides blood unit temperature monitoring and event logging capabilities, can be controlled by means of a wireless connection, and is powered by a high capacity Li-ion battery, which ensures long operating cycles. Moreover, it features a simple human interface, and appears rather small and light, thus resulting definitely suitable for the clinical settings. Once implemented, the system has been successfully validated by means of a Lab VIEW interface emulating a typical medical facility set-up. Currently, two on-site applications show a remarkable safety and speed improvement in performing cross-check procedures
Study on the preferential distribution of acetyl tributyl citrate in poly(lactic) acid-poly(butylene adipate-co-terephthalate) blends
Full text linkIn this work, the preferential distribution of acetyl tributyl citrate plasticiser (ATBC) in poly(lactic acid) (PLA)-poly(butylene adipate-co-terephthalate) PBAT blends has been investigated. Pure plasticised PLA and PBAT blends and their binary blends (PLA/PBAT with 80 wt% of PLA and 20 wt% of PBAT and PBAT/PLA with 80 wt% of PBAT and 20 wt% of PLA) containing different ATBC amount (from 5 to 20 wt%) have been investigated. Dynamic mechanical thermal analysis (DMTA) has been performed in order to evaluate the shift of the glass transition temperature (Tg) in both the polymer systems. The results obtained showed a larger shift for PLA than the PBAT and the calculated plasticiser partition coefficient for both binary blends revealed a preferential distribution of ATBC in the PLA phase rather than PBAT (KA/B = 1.07 for PLA-based system and KA/B = 1.45 for PBAT-based system). The results obtained have also been confirmed by the Hansen Solubility Parameters (HSPs) methodology. The study is finally augmented by the differential scanning calorimetry (DSC) and morphology analysis in order to demonstrate the possible effects of crystallinity on the plasticiser distribution in the binary blends
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
Semi-Supervised Classification with A*: A Case Study on Electronic Invoicing
Full text linkThis paper addresses the time-intensive task of assigning accurate account labels to invoice entries within corporate bookkeeping. Despite the advent of electronic invoicing, many software solutions still rely on rule-based approaches that fail to address the multifaceted nature of this challenge. While machine learning holds promise for such repetitive tasks, the presence of low-quality training data often poses a hurdle. Frequently, labels pertain to invoice rows at a group level rather than an individual level, leading to the exclusion of numerous records during preprocessing. To enhance the efficiency of an invoice entry classifier within a semi-supervised context, this study proposes an innovative approach that combines the classifier with the A* graph search algorithm. Through experimentation across various classifiers, the results consistently demonstrated a noteworthy increase in accuracy, ranging between 1% and 4%. This improvement is primarily attributed to a marked reduction in the discard rate of data, which decreased from 39% to 14%. This paper contributes to the literature by presenting a method that leverages the synergy of a classifier and A* graph search to overcome challenges posed by limited and group-level label information in the realm of electronic invoicing classification
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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