1,720,956 research outputs found
Rapid Fabrication of Electro-Adhesive Devices with Inkjet Printed Electrodes
Full text linkThis letter proposes a procedure for the rapid prototyping and on-demand manufacturing of thin film flexible electro-adhesive devices (EADs) made with a commercial polyimide dielectric layer, inkjet printed interdigitated silver electrodes and blade coated silicone elastomer encapsulation backing. As a proof demonstration, flexible thin-film EADs featuring 9.6 cm2 active area, 315 μm thickness and 0.7 g weight have been manufactured and tested over different adhering substrates showing peak adhesive shear stresses of up to 56.67 kPa, fast response time (11 ms for initial activation and 0.3 s for full electrification) and little energy requirements (from 1.3 mJ for initial activation to 20 mJ for full electrification and with a subsequent power consumption of about 1 mW for long-term grasp holding). Practical application of the manufactured EADs within a gripper for the grasping and handling of real objects that include a glass bottle, a hollow carbon fiber tube, a cardboard box, a box with thin polypropylene envelope and a polypropylene bottle is also demonstrated
Assessing the Relationships between Interdigital Geometry Quality and Inkjet Printing Parameters
Full text linkDrop on demand (DoD) inkjet printing is a high precision, non-contact, and maskless additive manufacturing technique employed in producing high-precision micrometer-scaled geometries allowing free design manufacturing for flexible devices and printed electronics. A lot of studies exist regarding the ink droplet delivery from the nozzle to the substrate and the jet fluid dynamics, but the literature lacks systematic approaches dealing with the relationship between process parameters and geometrical outcome. This study investigates the influence of the main printing parameters (namely, the spacing between subsequent drops deposited on the substrate, the printing speed, and the nozzle temperature) on the accuracy of a representative geometry consisting of two interdigitated comb-shape electrodes. The study objective was achieved thanks to a proper experimental campaign developed according to Design of Experiments (DoE) methodology. The printing process performance was evaluated by suitable geometrical quantities extracted from the acquired images of the printed samples using a MATLAB algorithm. A drop spacing of 140 μm and 170 μm on the two main directions of the printing plane, with a nozzle temperature of 35◦C, resulted as the most appropriate parameter combination for printing the target geometry. No significant influence of the printing speed on the process outcomes was found, thus choosing the highest speed value within the investigated range can increase productivity
Experimental characterization of a multilayer silicone-based electroactive patch for gripper applications
No full textFlexible thin-film Electro-Adhesive Devices (EADs) represent a promising technology with great potential for gripper applications. Generally, the gripping action of an EAD is due to the electrostatic force induced by an electric field produced by applying a voltage across a couple of electrodes that are embedded between dielectric substrates. This paper presents a novel manufacturing process and the experimental characterization of a multilayer electro-adhesive gripper. The proposed device employs highly elastic silicone (PDMS) thin-film as the grasping layer, i.e., the dielectric layer that comes in contact with the grasped object, a carbon-black mixture in a silicone compound for the electrodes, and a rigid polyimide thin-film as the backing layer, i.e., the dielectric layer on the backside of the EAD. A fabrication methodology is illustrated, which starts from a casting of thin conductive electrodes on a polyimide film, followed by a laser-cutting operation to shape the electrodes and a blade casting process to encapsulate the overall system in a PDMS compound. Different prototypes obtained through this manufacturing procedure have been experimentally evaluated through a testing campaign conducted on three groups of specimens, each composed of five identical samples, with a different electrode thickness per group. Samples are tested for electrostatic shear stress and electrical breakdown during the grasping of paper substrates, identifying the best performing EAD group
Inkjet printed thin-film electro-Adhesive device: Manufacturing and characterization
No full textThis paper describes the development of an electro-Adhesive gripper with silver interdigitated electrodes that are inkjetprinted on a pre-fabricated flexible dielectric film made of polyether ether ketone (PEEK), which also acts as the gripper adhering surface, and encapsulated in a blade-casted silicone elastomer backing layer. After a description of the manufacturing approach, the paper presents and discusses the results of the electro-mechanical characterization of two fabricated nominally identical electro-Adhesive devices, by specifically focusing on: electrically-induced adhesion shear stress, capacitance variation, energy and power consumption
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
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