Search results for "Radiation"
showing 10 items of 5298 documents
Optical absorption of torus-shaped metal nanoparticles in the visible range
2007
Received 22 November 2007; published 19 December 2007We theoretically and experimentally investigated the optical response of a thin metal nanotorus in the visiblerange. The close formulas describing the extinction cross sections of a torus are obtained in the nonretardedapproximation. We demonstrate a good agreement between numerical simulations and experimental data. Ourfindings show that the main resonance is highly sensitive to the external medium and the geometrical param-eters of the particle.DOI: 10.1103/PhysRevB.76.245422 PACS number s : 78.67.Bf, 73.20.Mf, 78.20.Ci
Clonal differences in growth and phenolics of willows exposed to elevated ultraviolet-B radiation
2003
Abstract In this study, the effects of elevated ultraviolet-B (UV-B, 280–320 nm) radiation on growth and leaf phenolics were evaluated in clones of dark-leaved willow ( Salix myrsinifolia Salisb.) and tea-leaved willow ( Salix phylicifolia L.). Willows were raised for one growing season in an irradiation field, where they were exposed either to a constant 50% increase in UV-B CIE radiation simulating 20–25% ozone depletion or to a small increase in UV-A radiation (320–400 nm). Control willows were grown in the irradiation field under solar radiation (ambient control). Despite the high constitutive concentrations of a UV-absorbing leaf flavonoid, dihydromyricetin, UV-treatments clearly reduc…
Assessment of contamination of <em>Salmonella</em> spp. in imported black pepper and sesame seed and salmonella inactivation by gamma irr…
2021
This study shows the frequency of seeds samples contaminated by Salmonella spp. collected randomly from local markets; on 30 black pepper sample no contaminated sample was found while Salmonella spp. was detected in 3 of 36 (8.3%) analyzed sesame samples; three different serotypes were identified: S. Montevideo, S. Stanleyville e S. Tilene. The efficacy of gamma irradiation to inactivate Salmonella Montevideo in black pepper and sesame irradiated between 1 and 5 kGy was evaluated. 3 kGy is sufficient to reduce of 3-4 log CFU/g; whereas 5 kGy have been need to reduce 5.5-6 log CFU/g for samples of black pepper and sesame. No statistically significant differences were found between black pepp…
Photochemical sample treatment for extracts clean up in PCB analysis from sediments.
2013
Sample purification can be considered the most polluting step of the whole analytical process for PCBs determination in sediment samples. The use of photochemical sample treatment represents an alternative methodology for extracts clean up allowing for a reduction of the used amount of organic solvents. The first application of a photochemical sample treatment for the selective removal or reduction of organic substances interfering with PCBs analyses in sediments is reported. The method's efficiency and robustness were compared with currently used chromatographic purification. Quality parameters such as recovery, linearity and reproducibility were studied. The entire procedure was validated…
SU-FF-T-62: Dosimetric Evaluation of An Internal Shielding Used with a HDR Skin Applicator
2009
Purpose: The Valencia HDR skin applicators are accessories of the microSelectron HDR afterloading system (Nucletron) cup shaped to limit the dose to the irradiation area. Applicators sizes are: diameter 2 and 3 cm. The typical prescription depth is 3 mm. This work aims to evaluate the backscatter and electron contamination of an internal shielding used to reduce the dose to the ocular globe when the lesion is located at the eyelid. Monte Carlo(MC) and experimental methods have been used. Method and Materials: The geometry has been: the Valencia applicator (2 cm diameter) on the surface of a solid polystyrene slab phantom; inside, a 2 mm lead slab located at 3 mm depth. MC simulation charact…
Characterisation of two new radiochromic gel dosimeters TruView™ and ClearView™ in combination with the vista™ optical CT scanner: A feasibility study
2018
This study aims at characterising the properties of TruView™ and ClearView™ two new gel dosimeters (Modus Medical Devices Inc.) and at studying the feasibility of relative dosimetry using these dosimeters and the Vista™ Optical CT scanner to accurately evaluate dose.In this work, we investigated key dosimetric aspects (dose response, energy and dose rate dependence) and stability of these radiochromic gels initiated in preliminary works (Huet et al., 2017; Colnot et al., 2017) using spectrophotometric measurements. Moreover, by mean of optical CT scanning (Vista™), their performances to measure relative depth dose (PDD) and cross profiles were analysed.TruView™ and ClearView™ present a line…
Imaging of Located Buried Defects in Metal Samples by an Scanning Microwave Microscopy
2011
Abstract A non-destructive method is proposed to detect the located buried defects using scanning microwave microscopy. Based on the “skin effect”, our recent developments authorize 3D tomography with nanometric resolution. This technique associates the electromagnetic microwave measurement using a Vector Network Analyzer (VNA) with the nanometer-resolution positioning capabilities of an Atomic Force Microscope. At each used frequency, an incident electromagnetic wave is send to the sample and the reflected wave gives information on a specific depth layer in the material. With a large bandwidth of frequencies, a 3D tomography is allowed inside the material. With characteristic tools of nano…
Astrophysical S-factor for the $^{2}H(ρ,γ)^{3}$ He reaction at big-bang nucleosynthesis energies
2020
10th European Summer School on Experimental Nuclear Astrophysics , Catania, Italy, 16 Jun 2019 - 23 Jun 2019; The European physical journal / Web of Conferences 227, 02015 (2020). doi:10.1051/epjconf/202022702015
Threshold Neutral Pion Photoproduction on the Proton
2015
The neutral pion photoproduction on the proton near threshold has a very small scattering cross section when compared to the charged channels, which in ChPT is explained by strong cancellations between the lowest order pieces. Therefore it is very sensitive to higher-order corrections of chiral perturbation theory. We perform a fully covariant calculation up to chiral order p^3 and we investigate the effect of the inclusion of the Delta(1232) resonance as an explicit degree of freedom. We show that the convergence improves, leading to a much better agreement with data at a wide range of energies.
The Image Gently in Dentistry campaign: promotion of responsible use of maxillofacial radiology in dentistry for children
2014
© 2014 Published by Elsevier Inc. The Image Gently in Dentistry campaign to be launched in September 2014 is a specific initiative of the Alliance for Radiation Safety in Pediatric Imaging, supported by organized dentistry and dental education as well as many dental specialty organizations. The objective of the campaign is to change practice by increasing awareness of the opportunities to improve radiation protection when imaging children in dental practices. Six practical steps are provided that underline the principle that one size does not fit all, especially when it comes to using radiography during pediatric dental procedures. When we image children, let us image gently: More is often …