1,720,999 research outputs found
Fabrication and Characterisation of Perovskite Thin Films for Photovoltaic Application
No full textThis paper presents an alternative way to obtain perovskite thin films for photovoltaic application. This technique results more competitive, scalable, low-cost, reproducible and is different from other most common methods of fabrication
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
Sensors for the monitoring of analytes in the sweat
Full text linkIn the last decade, can be found an exceptional growth in research activity relating to the development of wearable devices, capable of continuously monitoring the health conditions of the wearer by analyzing body fluids such as blood, urine, saliva, tears and sweat. Among the body fluids available, sweat is a biofluid of particular interest, as it allows a non-invasive, continuous and comfortable collection. Human sweat contains useful information on the health of an individual and therefore is an excellent biofluid for the detection of specific analytes. The most abundant ions in the sweat are Na+ and Cl- (10 - 100 mM), and their monitoring is useful in patients with cystic fibrosis. Other constituents are Ca2+, K+, ascorbic acid, glucose (0.1-10 μM) related to osteoporosis, hypoaldosteronism, scurvy and diabetes disease. The sweat pH is in the range 3 to 8 [1] [2] and indicates the level of metabolism and homeostasis of the body.
Wearable sensor needs to be flexible, compact and easily applicable. It must also offer a stable response, with high sensitivity and selectivity towards specific analytes [3]. Over the years, many wearable sensors for sweat monitoring have been developed, combining different form factors, substrates and sensing mechanism. In this work, electrochemical sensors based on polyaniline (PANi), which is pH sensitive, were studied. First, the best conditions of electrochemical deposition of PANi were studied [4], using as flexible substrate polyethylene terephthalate coated with indium-tin oxide (ITO-PET). In order to improve the sensor performance electrodes were also modified by electrochemical deposition of reduced graphene oxide (rGO). All samples were characterized by XRD, SEM and EDS analysis in order to study morphology and evaluate the crystalline phases of the deposited PANi. The electrodes were tested as pH sensors using different buffer solutions, from 2 to 8, by Open Circuit Potential (OCP) technique. The ITO-PET/rGO/PANi electrodes show good behavior in terms of sensitivity (62.3 mV/pH), very close to Nernstian response of 59 mV/pH and reproducibility of 3.8%. Flexibility and mechanical stability tests were carried out on the sensor to evaluate both the wearability and mechanical resistance. In addition, interference tests, in the presence of competing ions such as Na+, Cl-, K+, NH4+, aimed to verify the selectivity were also performed
Ni alloy nanowires as high efficiency electrode materialsnfor alkaline electrolysers
No full textHydrogen production by water electrolysis (WE) is a very promising technology
because it is a pollution-free process especially if renewable sources are
employed to energy supply. Nowadays, the cost of hydrogen production by WE
is higher than other available technologies, which makes WE not competitive.
Many efforts have been made to improve WE performance, through the use of
electrodes made of transition metal alloys as cathode and compound of metal
oxide as anode [1].
In the field of water-alkaline electrolyzer, the development of cheap
nanoporous based nickel electrodes with high electrocatalytic features is one of
the potential approaches to increase the WE performance [2].
A facile method for obtaining nanostructured electrodes is template
electrosynthesis. Through this method, we have fabricated electrodes formed
of Ni nanowires and its alloys that have a very high surface area. In previous
works, we have shown that water-alkaline electrolyzer with Ni nanowires
electrodes covered by nanoparticles of IrO2 as an anode and Pd as a cathode
have good and stable performance also at room temperature [2-5].
In this work, the attention has been focused on the fabrication of nickel-alloy
electrodes. Three different alloys (Ni-Co, Ni-Zn and Ni-W) at different
composition were studied in order to found the best alloy and relative best
composition. Nanostructured electrodes were obtained by template
electrodeposition using a nanoporous membrane and starting from aqueous
solutions containing the two elements of the alloy at different concentrations.
We found that composition of alloys can be tuned by electrolyte composition
and also depends on the difference on the redox potential of elements and on
the presence of complexing agents in deposition bath.
The chemical and morphological features of these nanostructured electrodes
will be presented and discussed. Furthermore, electrochemical and
electrocatalytic tests aimed to establishing the best alloy composition were
carried out for both hydrogen and oxygen evolution reaction. Then, test
conducted at a constant current density in aqueous solution of potassium
hydroxide (30% w/w) will be also reported. For all investigated alloys we have
obtained very encouraging results
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