Search results for " Misure"
showing 10 items of 421 documents
Measurement of long-lived radionuclide activity induced in target components of a cyclotron used for [18F ]-[FDG] production
2019
The evaluation of high activity induced in target components in using a medical cyclotron to produce positron-emitting radionuclides for PET (Positron Emission Tomography) diagnostic studies is one of important issue and involves radiation protection concepts when operators are engaged in maintenance and/or substitution of a target or its components. Most of replaced target components are generally classified and stored in a Pb-shielded container in order to wait for their radioactive decay. However, after some years, it can be necessary to start with the removal of the oldest parts, for a temporary storage of the fresh activated ones. The feasibility of these operations and the waste final…
Coincidence-Summing corrections in high resolution gamma-ray spectrometry: simplified analytical expressions
2010
Simplified expressions to determine the coincidence-summing correction factors by using a matrix representation of a decay scheme are reported. Expressions can be used directly for point sources, with the introduction of full-energy-peak and total efficiencies, while for extended sources a more complex procedure, though approximate, is suggested.
On the feasibility of dating the age of a nuclear incidental event by gamma-ray spectrometry of environmental samples
2019
The dating of a nuclear incidental event is an important element for the assessment of its enviromental impact and radiation protection implications on the involved population. In this framework, a procedure has already been proposed to determine the age of a nuclear event by measuring through a gamma-ray spectrometric analysis the activity of two fission products in a small sample of uranium irradiated for a short time in a nuclear reactor [1,2]. However, It may be useful to extend the application of the above mentioned procedure for assessing the “timing of occurrence” of an incidental event considering other samples and in particular, by sampling and measuring environmental samples. The …
NUCLEAR MAGNETIC RESONANCE RELAXOMETRY AND IMAGING FOR DOSIMETRY WITH AGAROSE FRICKE GEL
2016
Introduction: Fricke Xylenol Gel (FXG) dosimetric system is based on the radiation induced oxidation of ferrous to ferric ions. In this kind of gels it can occur that ferrous and ferric ions diffuse in the gel matrix. To preserve the spatial distribution of the dose from diffusion, Fricke gels must be undergoing measurement within a few hours of their irradiation. Thus, the spatial integrity of the dose distribution in the Fricke gel is maintained. The oxidation of ferrous ions also causes a reduction of the longitudinal nuclear magnetic relaxation time which can be measured by means of nuclear magnetic resonance (NMR) instrumentation. In this work we performed NMR relaxometry and MR imagin…
Electron Spin Resonance and Thermoluminescence dating of shells and sediments from Sambaqui (shell mound) Santa Marta II, Brazil
2020
In Tupi, the word Sambaqui means “mound of shells”. These archaeological sites are cultural vestiges left by the prehistoric occupation of the Brazilian coast from five to six thousand years ago. Mollusks, fishes, and other marine edible foods were important for the survival of this population. The remains of foods, mainly shells, were heaped up, giving a mound of different proportions, which became part of the landscape of the Brazilian coastal plain. Due to the large number of Sambaquis in Brazil and considering that Sambaqui Santa Marta II, Laguna, SC, has not yet been dated, Electron Spin Resonance (ESR) measurements were performed in aragonite shells collected from different layers of …
EPR dating of shells from Malhada Marsh, Rio de Janeiro, Brazil
2020
The formation of the coastal plain of the Brazilian sea is mainly due to the fluctuation of relative sea level in the past. Armacao dos Buzios or simply Buzios is a municipality in the microregion of lakes, in the state of Rio de Janeiro. In this region there is a lowland area about two meters above current sea level. This lowland area is also known as coastal plain of Una River. It is expected that during the Holocene period the sea level reached a maximum about 2.5 meters above the current level. During that time billions of mollusks lived and proliferated in the shallow waters around the coastal plain of the Una River. As they died their shells formed a layer in the soil including Malhad…
VERIFICA DELL’ATTECCHIMENTO DEGLI INNESTI-TALEA DI VITE DOPO LA FORZATURA MEDIANTE TECNICHE TERMOGRAFICHE E MECCANICHE
2016
Grafting is an important technique for getting good yields in plant multiplication. Understanding the success of the graft after the incubation room is important to the evaluation of the suitable grafting for the open field (nursery). Successful grafting in vines requires the development of a functional vascular system between the scion and the rootstock. The graft compatibility and its augmentation depend upon various natural factors like environment, weather, soil conditions and protective measures etc. The present study examines the capability of thermography, mechanical and electrical techniques to assess the graft quality and successful of Vitis vinifera after the incubation room. Afte…
IEEE Std. 1459 power quantities ratio approaches for simplified harmonic emissions assessment
2018
The paper investigates the suitability of using power ratio parameters for harmonic emissions assessment at the point of common coupling (PCC). The study is carried out starting from the IEEE Std. 1459-2010 apparent power decomposition, where power factors are defined for evaluating line utilization and harmonic pollution levels. In addition, the study investigates the behavior of new parameters, which are expressed in terms of ratio between IEEE Std. 1459-2010 power quantities. The study is carried out for both single-phase and three-phase case, also considering the presence of capacitors. ? 2018 IEEE.
Applicazione della tecnica HFMEA in radioterapia
2014
Equilibri di idrolisi ad alta temperatura
2009
L’idrolisi di molti ioni metallici dà spesso luogo alla formazione di specie mono e polinucleari. Nel caso di cationi quali Ga(III), Al(III), Cr(III) le difficoltà riscontrate nella raccolta dei dati sono essenzialmente dovute alla lentezza degli equilibri in studio; ciò ha causato disaccordo tra i dati di letteratura sia sulla natura delle specie formate che sulla loro stabilità. In assenza di un opportuno catalizzatore per lo studio a temperatura ambiente, l’unico modo per aumentare la velocità delle reazioni è aumentare la temperatura, in modo tale da ottenere stati di reale equilibrio. Un aumento della temperatura rende complicata la termostatazione dei reattivi e la loro aggiunta dall’…