1,720,974 research outputs found
Effect of nanofiber proximity on the mechanical behavior of high volume fraction aligned carbon nanotube arrays
No full textThe effect of nanofiber proximity on the mechanical behavior of nanofiber arrays with volume fractions (V f) from 1% to 20% was quantified via nanoindentation of an aligned carbon nanotube (A-CNT) array. The experimental results show that the indentation modulus for A-CNT arrays has a highly non-linear scaling with the CNT V f, leading to modulus enhancements of up to ∼600× at V f = 20%. Modeling illustrates that the origin of the highly non-linear trend with V f is due to the minimum inter-CNT spacing, which is shown to be more than an order of magnitude larger than the graphitic spacing.United States. Army Research Office (Contract No. W911NF- 07-D-0004)United States. Army Research Office (Contract No. W911NF-13-D-0001)Scientific and Technical Research Council of Turkey (2214-International Research Fellowship Programme)NECST Consortiu
High Electromechanical Response of Ionic Polymer Actuators with Controlled-Morphology Aligned Carbon Nanotube/Nafion Nanocomposite Electrodes
No full textAuthor Manuscript 2011 October 8Recent advances in fabricating controlled-morphology vertically aligned carbon nanotubes (VA-CNTs) with ultrahigh volume fraction create unique opportunities for markedly improving the electromechanical performance of ionic polymer conductor network composite (IPCNC) actuators. Continuous paths through inter-VA-CNT channels allow fast ion transport, and high electrical conduction of the aligned CNTs in the composite electrodes lead to fast device actuation speed (>10% strain/second). One critical issue in developing advanced actuator materials is how to suppress the strain that does not contribute to the actuation (unwanted strain) thereby reducing actuation efficiency. Here, experiments demonstrate that the VA-CNTs give an anisotropic elastic response in the composite electrodes, which suppresses the unwanted strain and markedly enhances the actuation strain (>8% strain under 4 V). The results reported here suggest pathways for optimizing the electrode morphology in IPCNCs using ultrahigh volume fraction VA-CNTs to further enhanced performance.United States. Army Research Office (Grant W911NF-07-1-0452)National Institutes of Health (U.S.) (Grant R01-EY018387-02)United States. Multidisciplinary University Research Initiativ
Conductive Filler Morphology Effect on Performance of Ionic Polymer Conductive Network Composite Actuators
No full textSeveral generations of ionic polymer metal composite (IPMC) actuators have been developed since 1992. It has been discovered that the composite electrodes which are composed of electronic and ionic conductors, have great impact on performance of ionic polymer actuators by affecting strain level, efficiency and speed. One of important factors in composite electrodes is the shape and morphology of electronic conductor fillers. In this paper, RuO2 nanoparticles and vertically aligned carbon nanotube (Va-CNT) are used as conductor fillers. Making use of unique properties of Va-CNT forests with ultrahigh volume fraction in Nafion nanocomposite, an ionic polymer actuator is developed. Ion transport speed is greatly increased along CNT alignment direction. The high elastic anisotropy, arising from the high modulus and volume fraction of Va-CNTs, enhances actuation strain while reducing the undesirable direction strain. More than 8% actuation strain under 4 volts with less than one second response time has been achieved.United States. Army Research Office (Grant No. W911NF-07-1-0452)Boeing CorporationAirbus IndustrieBoeing Aerospace CompanyEmpresa Brasileira de AeronáuticaLockheed MartinSaab (Firm)Spirit AeroSystemsTextron, inc.Composite Systems TechnologyTohoTenax IncMassachusetts Institute of Technology. Nano-Engineered Composite aerospace STructures ConsortiumTürkiye Bilimsel ve Teknolojik Araştırma KurumuSpain. Ministerio de Educación y Ciencia (FPU grant AP-2004-6264
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
Appropriate Similarity Measures for Author Cocitation Analysis
Get PDFWe 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
Get PDFWe 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
koamabayili/VECTRON-author-checklist: VECTRON author checklist
No full textWe have done our best to complete the author checklist relating to the use of animals in the hut study. Note that the objective for the hut study was to evaluate the IRS treatment applications for residual efficacy against Anopheles mosquitoes, including the local An. coluzzii mosquito population. Cows were only used to attract mosquitoes into the huts and no tests were carried out directly on the cows. The author checklist is intended for use with studies where experiments are carried out on animals, which is why we have had such difficulty in completing this for the hut study, as many of the questions do not relate to how the cows were used
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