1,720,958 research outputs found
Polymer-grafted QCM chemical sensor and application to heavy metal ions real time detection
No full textA flow type quartz crystal microbalance (QCM) chemical sensor was
developed for monitoring heavy metal ions in aqueous solutions (that is suitable
for environmental monitoring). The sensor is based upon surface chelation of the
metal ions at multifunctional polymer modified gold electrodes on 9 MHz AT-cut
quartz resonators, functioning as a QCM. New processes have been developed which
enable to obtain surface-modified gold electrodes with high heavy metal ions
complexing ability. These polymer grafted QCM sensors can selectively adsorb heavy
metal ions, such as copper, lead, chrome and cadmium, from solution over a wide
range from 0.01 to 1000 ppm concentration by complexation with functional groups
in the polymers. Cations typically present in natural water did not interfere with
the detection of heavy metals. X-Ray Reflectivity (XRR) and Total Reflection X-ray
Fluorescence (TXRF) were carried out to characterise the unmodified and modified
gold surfaces as well as to verify the possibility to selectively bond and remove
metal ions
BIOCOMPOSITE FERTILISER MATERIALS
No full textThe present invention relates to the preparation of biocomposite materials with a fertilizing action obtainable by crosslinking protein hydrolyzates with epoxidized vegetable oils. The materials according to the invention will also contain suitable fillers and specific additives
Hydrolyzed protein based materials for biodegradable spray mulching coatings
Full text linkLow density polyethylene (LDPE) films are widespread used in agriculture
for soil mulching. The use of LDPE mulching films causes the serious drawback of
huge quantities of waste to be disposed of. Over the last years the growing
environmental awareness has been prompting the research to develop a new
generation of mulching products starting with raw materials from renewable origin.
These materials have to retain their physical and mechanical properties while in use
and have to be compostable or biodegradable at the end of their life, degrading via
micro-organisms into carbon dioxide or methane, water and biomass. The research
is focused on the development of novel biodegradable polymeric materials based on
hydrolyzed proteins, derived from waste products of the leather industry.
Biodegradable soil mulching coatings were realized with these biodegradable
polymeric materials by means of spray techniques; the coatings were tested in a
Ligustrum ovalifolium cultivation carried out inside a greenhouse. This paper
describes the functionalities of the new bio-based mulching coatings, which were
developed and tested in real scale greenhouse cultivation tests. During the trial, the
biodegradable soil mulching materials showed suitable properties for an efficient
and profitable use in agriculture. The innovative biodegradable spray coatings
lasted up to 18 months. The biodegradable materials could be the environmentally
friendly alternatives to synthetic petro-chemical polymers and could contribute to a
sustainable agriculture
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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