1,721,020 research outputs found
Carbon dioxide determination in atmosphere and seawater: Approaches for the comparability of measurement results
No full textThe rising levels of carbon dioxide in the atmosphere are responsible for fundamental changes occurring in seawater carbonate chemistry. For both air and water, there is a pressing need to assure metrological traceability thus obtaining comparable measurement results on spatial and temporal scales. At INRIM several activities are carried out to establish the metrological traceability for carbon dioxide measurement results. Two primary methods, the gravimetry and the dynamic dilution, are used for the preparation of reference standards for composition which can be used to calibrate sensors and analytical instrumentation for carbon dioxide determination both in atmosphere and seawater. An overview of possible approaches is given
Mesoscale structures at complex fluid-fluid interfaces: A novel lattice Boltzmann/molecular dynamics coupling
Full text linkComplex fluid-fluid interfaces featuring mesoscale structures with adsorbed particles are key components of newly designed materials which are continuously enriching the field of soft matter. Simulation tools which are able to cope with the different scales characterizing these systems are fundamental requirements for efficient theoretical investigations. In this paper we present a novel simulation method, based on the approach of Ahlrichs and Dünweg [Ahlrichs and Dünweg, Int. J. Mod. Phys. C, 1998, 9, 1429], that couples the "Shan-Chen" multicomponent lattice Boltzmann technique with off-lattice molecular dynamics to simulate efficiently complex fluid-fluid interfaces. We demonstrate how this approach can be used to study a wide class of challenging problems. Several examples are given, with an accent on bicontinuous phase formation in polyelectrolyte solutions and ferrofluid emulsions. We also show that the introduction of solvation free energies in the particle-fluid interaction unveils the hidden, multiscale nature of the particle-fluid coupling, allowing us to treat symmetrically (and interchangeably) the on-lattice and off-lattice components of the system. © 2013 The Royal Society of Chemistry
Interplay between distribution of live cells and growth dynamics of solid tumours
No full textExperiments show that simple diffusion of nutrients and waste molecules is not sufficient to explain the typical multilayered structure of solid tumours, where an outer rim of proliferating cells surrounds a layer of quiescent but viable cells and a central necrotic region. These experiments challenge models of tumour growth based exclusively on diffusion. Here we propose a model of tumour growth that incorporates the volume dynamics and the distribution of cells within the viable cell rim. The model is suggested by in silico experiments and is validated using in vitro data. The results correlate with in vivo data as well, and the model can be used to support experimental and clinical oncology
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
Metrologically traceable determination of the water content in biopolymers: INRIM activity
Full text linkWater content in materials is a key factor affecting many chemical and
physical properties. In polymers of biological origin, it influences their stability and
mechanical properties as well as their biodegradability. The present work describes
the activity carried out at INRiM on the determination of water content in samples
of a commercial starch-derived biopolymer widely used in shopping bags (Mater-
Bi (R)). Its water content, together with temperature, is the most influencing parameter
affecting its biodegradability, because of the considerable impact on the microbial
activity which is responsible for the biopolymer degradation in the environment. The
main scope of the work was the establishment of a metrologically traceable procedure
for the determination of water content by using two electrochemical methods, namely
coulometric Karl Fischer (cKF) titration and evolved water vapour (EWV) analysis.
The obtained results are presented. The most significant operational parameters were
considered, and a particular attention was devoted to the establishment of metrological
traceability of the measurement results by using appropriate calibration procedures,
calibrated standards and suitable certified reference materials. Sample homogeneity
and oven-drying temperature were found to be the most important influence quantities
in the whole water content measurement process. The results of the two methods were
in agreement within the stated uncertainties. Further development is foreseen for the
application of cKF and EWV to other polymers
The use of dynamic dilution by Mass Flow Controllers in the environmental monitoring of CO2: calibration issues and strategies
Full text linkGaseous pollutants determination in atmosphere is usually carried out by comparison methods with dedicated analysers, which need to be calibrated with proper certified reference gas mixtures. D ynamic dilution allows the generation of gas mixtures which can be employed either to calibrate the analysers or to validate gas mixtures contained in high pressure cylinders. The dynamic dilution is often achieved by using Mass Flow Controllers (MFCs) due to their ease of use and good level of reliability. The MFC sensors are based on heat exchange equations, therefore the response of these instruments is sensitive to the nature of the flowing gas. The different response can be taken into account through a so-called Gas Correction Factor (GCF), which can be computed when the gas properties are known. Neglecting the use of proper GCFs may result in a bias in the assignment of the molar fraction of dynamic mixtures. The present paper deals with the calculation carried out at INRIM of the GCF in the generation of dynamic mixtures of carbon dioxide in synthetic air at ambient level. The results obtained without using the GCFs are compared with those obtained by application of the correction, showing the presence of a systematic non-negligible bias
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
SEGA Z'AMANTS = Les amants ; BATEAU TALBER / Boris Vian ; J. Bellingham. La Pointe aux piments. HEY ! SEGA / M. Sega, M. Miquel et G. Sala ; Maria Sega
No full textBnF-Partenariats, Collection sonore - BelieveContient une table des matière
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