1,720,960 research outputs found
Micromanufacturing of Conductive Polymer Electrodes for Sensing Microsystems
No full textWearable technologies are receiving a growing attention from research and industry in many different scientific areas [1]. Many of the commercialized devices are mainly based on the detection of gravitational, electric or acoustic impulse and environmental sensors [2]. However, for various healthcare applications it is of vital importance to be able to analyse bodily fluids, detecting microscopic biomarkers in order to monitor health conditions in a continuous, not-invasive and localized way. For this reason, the realization of the realization of in-situ wearable electrochemical bio-sensors is highly needed since it will open the possibility of mass screening and personalized medicine [1]. Conductive polymers are well suited for wearable bio-sensor applications, due to their unique electrical and optical properties that can be selected by choosing among a broad range of available materials [3][4][5]. Moreover, they provide also biocompatibility, low cost and easy manufacturability. This thesis presents a low cost and simple method for fabricating an all polymeric device for pH monitoring. Indeed, pH is one of the keys indicator of wound infection and it is important to study its evaluation during wound healing in order to select the right therapy. The device consists of a microfluidic channel, for uid handling, and polymeric electrodes made of poly(3,4-ethylenedioxythiophene)-poly(styrenesulfonate) (PEDOT:PSS), one of the most promising conductive electrodes. The PEDOT layer has been created by spin-coating on a cyclic ole_n copolymer (COC) substrate and has been characterized by both contact and optical interferometry. In order to increase adhesion, isopropanol has been added to PEDOT before spin-coating and a post-process treatment with ethylene glycol has demonstrated to be crucial to increase the PEDOT conductivity and decrease its solubility in water, Electrodes coupled with microchannels were fabricated by mean of a single hot embossing process. The thesis presents a comparison between a standard hot embossing process with a soft embossing one (in which the mold is polymeric). Two different processes for fabrication the mold are discussed: direct milling of aluminum for the hard mold and soft lithography with polydimethilsiloxane on a polystyrene master. The polymeric electrodes obtained after embossing have been characterized by means of electrical and electrochemical measurements. In order to impart pH sensitivity, a pH sensitive layer of polyaniline has been electropolimerized on the PEDOT working electrode and characterized by means of SEM imaging and electrochemistry. Finally, the response of the device to a relevant range of pH is tested and validated by monitoring its potentiometric response. In conclusion, this thesis describes the development and characterization of an all polymeric microfluidic pH sensing system with integrated electrodes manufactured by means of a single-step embossing process.Mechanical, Maritime and Materials EngineeringPrecision and Microsystems Engineerin
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
Compliant Fluidic Control Structures: Concept and synthesis approach
No full textThe concept and synthesis approach for planar Compliant Fluidic Control Structures (CFCSs), monolithic flexible continua with embedded functional pores, is presented in this manuscript. Such structures are envisioned to find application in biomedicine as tunable microfluidic devices for drug/nutrient delivery. The functional pores enlarge and/or contract upon deformation of the compliant structure in response to external stimuli, facilitating the regulated control of fluid/nutrient/drug transport. A thickness design variable based topology optimization problem is formulated to generate effective designs of these structures. An objective based on hydraulic diameter(s) is conceptualized, and it is extremized using a gradient based optimizer. Both geometrical and material nonlinearities are considered. The nonlinear behaviour of employed hyperelastic material is modeled via the Arruda-Boyce constitutive material model. Large-displacement finite element analysis is performed using the updated Lagrangian formulation in plane-stress setting. The proposed synthesis approach is applied to various CFCSs for a variety of fluidic control functionalities. The optimized designs of various CFCSs with single and/or multiple functional pores are fabricated via a Polydimethylsiloxane (PDMS) soft lithography process, using a high precision 3D printed mold and their performances are compared with the numerical predictions.Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.Computational Design and MechanicsMicro and Nano Engineerin
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
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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