35 research outputs found
Synchrotron radiation representation in phase space
The notion of brightness is efficiently conveyed in geometric optics as
density of rays in phase space. Wigner has introduced his famous distribution
in quantum mechanics as a quasi-probability density of a quantum system in
phase space. Naturally, the same formalism can be used to represent light
including all the wave phenomena. It provides a natural framework for radiation
propagation and optics matching by transferring the familiar `baggage' of
accelerator physics (beta-function, emittance, phase space transforms, etc.) to
synchrotron radiation. This paper details many of the properties of the Wigner
distribution and provides examples of how its use enables physically insightful
description of partially coherent synchrotron radiation in phase space
Calibration of multi-layered probes with low/high magnetic moments
We present a comprehensive method for visualisation and quantification of the magnetic stray field of magnetic force microscopy (MFM) probes, applied to the particular case of custom-made multi-layered probes with controllable high/low magnetic moment states. The probes consist of two decoupled magnetic layers separated by a non-magnetic interlayer, which results in four stable magnetic states: ±ferromagnetic (FM) and ±antiferromagnetic (A-FM). Direct visualisation of the stray field surrounding the probe apex using electron holography convincingly demonstrates a striking difference in the spatial distribution and strength of the magnetic flux in FM and A-FM states. In situ MFM studies of reference samples are used to determine the probe switching fields and spatial resolution. Furthermore, quantitative values of the probe magnetic moments are obtained by determining their real space tip transfer function (RSTTF). We also map the local Hall voltage in graphene Hall nanosensors induced by the probes in different states. The measured transport properties of nanosensors and RSTTF outcomes are introduced as an input in a numerical model of Hall devices to verify the probe magnetic moments. The modelling results fully match the experimental measurements, outlining an all-inclusive method for the calibration of complex magnetic probes with a controllable low/high magnetic moment
International Geomagnetic Reference Field: the 12th generation
The 12th generation of the International Geomagnetic Reference Field (IGRF) was adopted in December 2014 by the Working Group V-MOD appointed by the International Association of Geomagnetism and Aeronomy (IAGA). It updates the previous IGRF generation with a definitive main field model for epoch 2010.0, a main field model for epoch 2015.0, and a linear annual predictive secular variation model for 2015.0-2020.0. Here, we present the equations defining the IGRF model, provide the spherical harmonic coefficients, and provide maps of the magnetic declination, inclination, and total intensity for epoch 2015.0 and their predicted rates of change for 2015.0-2020.0. We also update the magnetic pole positions and discuss briefly the latest changes and possible future trends of the Earth’s magnetic fiel
Standardisation of magnetic nanoparticles in liquid suspension
Suspensions of magnetic nanoparticles offer diverse opportunities for technology innovation, spanning a large number of industry sectors from imaging and actuation based applications in biomedicine and biotechnology, through large-scale environmental remediation uses such as water purification, to engineering-based applications such as position-controlled lubricants and soaps. Continuous advances in their manufacture have produced an ever-growing range of products, each with their own unique properties. At the same time, the characterisation of magnetic nanoparticles is often complex, and expert knowledge is needed to correctly interpret the measurement data. In many cases, the stringent requirements of the end-user technologies dictate that magnetic nanoparticle products should be clearly defined, well characterised, consistent and safe; or to put it another way—standardised. The aims of this document are to outline the concepts and terminology necessary for discussion of magnetic nanoparticles, to examine the current state-of-the-art in characterisation methods necessary for the most prominent applications of magnetic nanoparticle suspensions, to suggest a possible structure for the future development of standardisation within the field, and to identify areas and topics which deserve to be the focus of future work items. We discuss potential roadmaps for the future standardisation of this developing industry, and the likely challenges to be encountered along the way
PERSPECTIVAS DEL PROCESO DE GLOBALIZACIÓN Y SU INFLUENCIA SOBRE LOS DERECHOS HUMANOS ECONÓMICOS, SOCIALES Y CULTURALES
El escenario internacional se encuentra en constante transformación debido a lo que se ha denominado el proceso de “globalización”. Este afecta las relaciones internaciones interestatales e influye en la vida cotidiana de los individuos. El Derecho Internacional y más específicamente el Derecho Internacional de los Derechos Humanos no es ajeno a este proceso. La investigación afirma que nos encontramos frente a una etapa de transnacionalización de los Derechos Humanos, que permite que los individuos cuenten con mayor protección en ámbitos supranacionales. También hace especial mención a los derechos Económicos Sociales y Culturales, analiza el debate sobre el pluralismo jurídico y la eficacia diferencial. En la metodología empleada se revisan fuentes documentales y se realiza un análisis de algunos derechos particulares previstos en el Pacto de Derechos Económicos, Sociales y Culturales. Los planteamientos permiten afirmar que el proceso de globalización ha determinado la transnacionalización de los Derechos Humanos, surgiendo de dicho fenómeno consecuencias positivas y negativas en cuanto a su cumplimiento
Polivalenza di componenti bioattivi fenolici degli alimenti. Poster. Atti del XIV Congresso della Società Italiana di Scienza dell’Alimentazione
Validation of an isocratic HPLC method based on the use of ABZ+ plus phase for the simultaneous determination of methylxantines, chlorogenic acid, some hydroxy-benzoic and hydroxy-cinnamic acids. Application to cocoa, coffee, tea and cola-drinks
Valutazione SPME-2D-GC-TOF del profilo aromatico volatile del tartufo bianco d’Alba (Tuber magnatum Pico).
Total antioxidant activity of hazelnut skin (Nocciola Piemonte PGI): impact of different roasting conditions
The thin brown perisperm (skin) that envelops hazelnut kernels is usually removed after roasting process, leading a phenolic-rich by-product. Principal aim of this work was to characterise the total antioxidant activity of phenolic extracts obtained from roasted “Nocciola Piemonte PGI” hazelnuts skin. Different extraction solvents (methanol, acidified methanol, ethanol, acidified ethanol, and acetone/water) and different protocols (cold solvent-assisted extraction and semi-automated Soxhlet extraction) were employed. The influence of different roasting degree (180 °C/10 min and 180 °C/20 min) was also investigated. DPPHradical dot and ABTSradical dot+ radical-scavenging methods, ferrous ions chelation activity and inhibition of lipid peroxidation investigated in this study demonstrated significant antioxidant properties for hazelnut skin phenolics. The main mechanism involved appeared the antiradical activity, strictly related to the total phenolic content (r = −0.8798 and −0.8285 for DPPHradical dot and ABTSradical dot+ assays, respectively). The acidification of extraction solvents led to a significant decrease of antiradical activity, whilst the different roasting conditions significantly influenced the chelation activity and the inhibition of lipid peroxidation, showing higher effectiveness for high-roasted hazelnut skin extracts. Conversely, the direct measure of the antioxidant capacity of defatted hazelnut skins revealed higher ABTSradical dot+ scavenging properties for medium-roasted sample.info:eu-repo/semantics/publishe
Caratterizzazione chimica e proprietà antiossidanti della frazione polifenolica estratta da cuticola di semi di Corylus avellana L.
info:eu-repo/semantics/nonPublishe