Search results for "RADIATION"
showing 10 items of 5298 documents
High-energy radiation process, a "facile" and "versatile" approach to obtain PVP-graft- AA nanogels
2012
Poly(N-vinylpyrrolidone)-grafted-acrylic acid biocompatible nanogels (NGs) were prepared using an exiting industrial-type electron accelerator and setups, starting from semi-dilute aqueous solutions of a commercial PVP and the acrylic acid monomer. As a result, NGs with tunable size and structure can be obtained quantitatively. Sterility was also imparted at the integrated dose absorbed. The chemical structure of the NGs produced was confirmed through Fourier Transformer Infrared Spectroscopy (FT-IR). The molecular and physico-chemical properties of NGs, such as the hydrodynamic dimensions and surface charge densities, for various polymer and monomer concentrations in the irradiated solutio…
Photoactivity of Shape-Controlled TiO2 in Gas-Solid Regime Under Solar Irradiation
2018
Shape-controlled TiO2 materials have been tested as photocatalysts under both simulated and natural solar irradiation.
Rare-earth doped silica optical fibres for ionizing radiation detection
2016
Scintillating silica optical fibre sensors have shown interesting results for ionizing radiation monitoring and therefore can be useful for dosimetry applications in medical field. In fact, they enable a remote, punctual and real-time dose assessment (Mones et al., 2008). In addition, the high radiation hardness that characterizes silica optical fibers, makes these systems promising for radiation detection in high energy physics experiments (Chiodini et al., 2014). This work aims to review the recent progresses in the development and characterization of rare-earth doped silica fibres. The radioluminescent and dosimetric properties of Ce, Eu, Yb and Pr-doped silica matrices are described and…
Effects of radiation in accretion regions of classical T Tauri stars
2019
Context. Models and observations indicate that the impact of matter accreting onto the surface of young stars produces regions at the base of accretion columns where optically thin and thick plasma components coexist. Thus, an accurate description of these impacts is necessary to account for the effects of absorption and emission of radiation. Aims. We study the effects of radiation emerging from shock-heated plasma in impact regions on the structure of the pre-shock down-falling material. We investigate whether a significant absorption of radiation occurs and if it leads to a pre-shock heating of the accreting gas. Methods. We developed a radiation hydrodynamics model describing an accreti…
Outdoor Mean Radiant Temperature Estimation: Is the Black-Globe Thermometer Method a Feasible Course of Action?
2018
Urban planning has become one of the crucial action in order to address and mitigate the effect and the consequences of the global warming and it also entails different sectors of the urban context. The survey and control of the outdoor climatic conditions are among the involved sectors and mean radiant temperature is amid the most analyzed parameters. The aim of the paper is to investigate the effective suitability of one of the most used method in the assessment of the mean radiant temperature, namely the globe-thermometer method, in outdoor urban environment, singling out possible shortcomings and actual efficacy. Specifically, data obtained by measurement campaigns performed by means of…
Assessment of the mean radiant temperature in urban areas: methods at comparison
2018
Mean radiant temperature may play a pivotal role in the assessment of the outdoor environmental conditions in urban areas. However, its assessment in urban settings is not a simple task owing to the presence of complex and articulated environment and of solar radiation. The article aims to perform a comparison among the results yielded by different methods: the globe-thermometer method, and the six-directional technique. The scope of such a survey is an analysis of the actual appropriateness of the more practical, albeit less accurate, globe-thermometer method to outdoor environments. Furthermore, an analytical model, previously elaborated by the authors and here modified to make it applica…
The importance of reliable climatic data in the urban energy policy
2011
In the last years, more and more attention has been focused on energy issues, in particular at urban level, as it is pointed out by the Directive 2002/91/EC on the Energy Performance of Buildings. In fact, the building sector encompasses nearly 30% of the energy whole consumptions. To try to limit such consumptions, both central and local governments should plan effective policies, such as promoting the use of renewable sources and of more energy efficient buildings (e.g. by means of green coverings). But in order to do that, local administrations should provide reliable tools for engineers and technicians to plan such systems. Nowadays, several software are available; the weak point is the…
Mode I fracture toughness behaviour of epoxy resincarbon fiber composites cured by ionising radiation
2012
In this work Mode I fracture toughness behavior of Electron Beam cured unidirectional CFRP laminates is investigated by means of standardized Double Cantilever Beam (DCB) tests. A matrix system, comprising a DGEBA epoxy monomer and a typical initiator of cationic polymerization, was used and panel samples assembled by hand lay-up. Curing was achieved by 20 to 40 minutes irradiation on a pulsed 10 MeV Electron Beam accelerator. One batch of resin was also mixed with 10 phr of a PES thermoplastic monomer in order to enhance the matrix toughness. The influence of fibre-matrix adhesion, matrix toughening and matrix crosslinking density on the mode I delamination behavior have been investigated …
Epoxy resin-thermoplastic blends cured by ionising radiation. Structure/properties relationships
2009
Radiation curing of an epoxy resin based blend is carried out in order to produce polymer matrices for high-performance composites. A suitable choice of both curing process and formulation parameters allows to irradiate at about 60°C. Moreover hydrothermal ageing is performed on cured materials and their properties have been evaluated
Testing and linearity calibration of films of phenol compounds exposed to thermal neutron field for EPR dosimetry
2015
This paper reports the preliminary results obtained by Electron Paramagnetic Resonance (EPR) measurements on films of IRGANOX® 1076 phenols with and without low content (5% by weight) of gadolinium oxide (Gd2O3) exposed in the thermal column of the Triga Mark II reactor of LENA (Laboratorio Energia Nucleare Applicata) of Pavia (Italy). Thanks to their size, the phenolic films here presented are good devices for the dosimetry of beams with high dose gradient and which require accurate knowledge of the precise dose delivered. The dependence of EPR signal as function of neutron dose was investigated in the fluence range between 10(11) cm(-2) and 10(14) cm(-2). Linearity of EPR response was fou…