1,721,050 research outputs found
Thickness determination of the gilding on brass materials by XRF technique
No full textThe gold coating layer of the gold-plated brass objects was estimated using calibration curves obtained with a handheld X-ray fluorescence spectrometer (XRF). Calibration curves were obtained using reference materials (Au and brass) and intensity ratios of the X-ray fluorescence peaks generated in both the gold coating and the brass substrate. In addition, a calibration was also performed with the PLS (Partial Least Squares) multivariate analysis method. Good agreement was obtained by comparing the results of the different methods. The calibrations were successfully applied to gold-plated brass jewels and samples
Coating thickness of plated objects using XRF technique concentrations
No full textThe coating layer thickness of the double-layer objects was estimated using the concentration value of an element of the covering layer or of the substrate after obtaining suitable calibration curves using reference materials. The x-ray fluorescence technique was used with a handheld instrument to determine the concentration of elements. Various experimental configurations were built using gold- and silver-plated materials. The concentration calibrations curve as a function of coating layer thickness were successfully applied to gold-plated brass and copper jewelry, gold-plated samples and an ancient silver coin. The results obtained using the concentrations are in good agreement with those of other more elaborate methods
A method for emanation coefficient measurements of 222Rn and 220Rn from soils
No full textA new method to determine emanation coefficient of 222Rn and 220Rn from soil samples is presented. The aim of the present work is to obtain a useful, rapid and noise free method to make soil sample measurements. The method is based on the measurements of specific activities of 220Rn and 222Rn in a sealed chamber using α-spectrometry and on the measurements of specific activities of 232Th and 226Ra using γ-spectrometry. The specific activities of radon isotopes are measured using the electrostatic collection of polonium isotopes on the silicon surface barrier detector mounted at the top of a chamber containing the soil sample. In the chamber volume, the process of balance has been studied and the results show that the time needed to achieve the equilibrium is shorter than in the presence of free exhalation. © 1997 Published by Elsevier Science Ltd
ANALYSIS BY SCANNER OF TRACKS PRODUCED BY RADON ALPHA PARTICLES IN CR-39 DETECTORS
No full textThe most used passive detectors for Radon measurement are the CR39s, both for the good stability of the material and for the practicality of use. But, commercial reading systems are expensive and not always fast. The aim of the present work was the development of a method for a rapid, efficient and economic evaluation of the result of the indoor Radon measurement performed with CR39 detectors. The analysis and acquisition of detector images were performed using a photo scanner and the free ImageJ software. Several groups of CR-39 detectors were exposed, developed and analysed. Calibration curve was obtained in a wide range of exposure values (200-12 000 kBq·h·m -3) to allow the procedure to be applied in all possible measurement environments. Furthermore, a statistical study was carried out on the shape and size of nuclear tracks after chemical development. The dependence of the track size on Radon exposure was effective in showing the trace saturation effect as well
Gli Incusi della Collezione Numismatica del Museo Campano: presentazione preliminare
No full textGli esemplari inediti delle serie incuse di Magna Grecia, attestate nella gamma di emissioni tra seconda metà del VI sec. a.C. e prima metà del V sec. a.C., nella collezione del Museo Campano Provinciale di Capua, rappresentano una presenza inconsueta in ambito campano: la questione si innesta sulla genesi e sui processi di formazione della raccolta. Inoltre, i materiali esaminati si segnalano per l’ apporto di nuovi elementi allo studio delle monetazioni di pertinenza. L’analisi condotta mediante ED-XRF ha consentito di puntualizzare la composizione elementale degli esemplare e di escludere, nella maggioranza dei casi, il fenomeno dell’arricchimento in superficie (Vedi anche articolo, pag. 75)
Development of radon transport model in different types of dwellings to assess indoor activity concentration
No full textThe influence of different building types on the activity concentration of Radon indoor is studied through transport models in soil and building materials. The numerical solutions of the relevant transport equations are solved by the finite differences method (FDM) and used to evaluate the indoor Radon activity concentration. Several boundary conditions are introduced to simulate the Radon entry into the buildings from soils and to assess the Radon activity concentration at the different floors. The types of dwelling investigated differ in the position of the lower floor respect to the ground. Comparisons are made to modeling assessments obtained considering different soil characteristics underneath the building and building materials to simulate indoor Radon activity concentration. These investigations lead to the conclusion that, in addition to the nature of the soil and building materials, the position of lower floor of dwellings plays a significant role in determining the amount of radon entry into residential buildings. This work is effective to assess the health hazards coming from the Radon accumulation in living environments
ANALYSIS by SCANNER of TRACKS PRODUCED by RADON ALPHA PARTICLES in CR-39 DETECTORS
No full textThe most used passive detectors for Radon measurement are the CR39s, both for the good stability of the material and for the practicality of use. But, commercial reading systems are expensive and not always fast. The aim of the present work was the development of a method for a rapid, efficient and economic evaluation of the result of the indoor Radon measurement performed with CR39 detectors. The analysis and acquisition of detector images were performed using a photo scanner and the free ImageJ software. Several groups of CR-39 detectors were exposed, developed and analysed. Calibration curve was obtained in a wide range of exposure values (200–12 000 kBq·h·m −3) to allow the procedure to be applied in all possible measurement environments. Furthermore, a statistical study was carried out on the shape and size of nuclear tracks after chemical development. The dependence of the track size on Radon exposure was effective in showing the trace saturation effect as well
Gold-coating thickness determination on Ag, Cu, Fe, and Pb using a handheld X-ray instrument
No full textHere, the X-ray fluorescence technique is used to determine the thickness of a coating layer as well as to analyze the surface of objects. Four metals (Ag, Cu, Fe, Pb) were covered with increasing thicknesses of gold. The measurements were performed with a commercial handheld instrument, X-SORT (Spectro). In double layers, the thickness of the covering layer was assessed by (a) the ratio between the most intense fluorescence lines of the covered element, (b) a cross-ratio between two lines of the elements in the two layers, and (c) the ordinary partial least squares (PLS) regression method. In all cases, the curves obtained could be used for the quantitative determination of the thickness. The experimental data followed the theoretical trend even though the values of the attenuation parameters were not always in agreement with the theoretical ones. Comparisons and discussion of the results of the different approaches and also with models in the literature are made. The methods studied were applied to determine the nature of the coating layers of some gilded objects and proved to be suitable for estimating the thickness of gold by providing results that were in good agreement with each other
Estimation of Ag coating thickness by different methods using a handheld XRF instrument
No full textPrecious objects are often made from a thin layer of metal (gold or silver) superimposed on another metal or alloy. Non-invasive XRF analysis is widely used on these objects to determine the composition and thickness of the surface layer. Here, silver surface thickness of two-layered metal samples using an ED-XRF handheld spectrometer is estimated by different methods whose results are compared. These methods involved the relationships between the intensities of the characteristic lines of Kα, Kβ, Lα and Lβ of Ag and of elements present in the substrate (Cu, Fe, Pb) and some of their combinations, as well as the PLS regression. Reference layers were used to derive the calibration curves of each methodology. PLS method was the most accurate, but the other methods were also found suitable for the purpose. Applications have been successfully made on an ancient Roman coin and a modern silver-plated object
Innovative methodologies for the analysis of radon time series
Full text linkThe present contribution is a part of a wide and detailed study on the long-term radon time series specific activity using novel methods of analysis with different aims: to extract the general trend; to evidence and distinguish endogenous and climatic dependences; to identify anomalies in order to show the correlation with geophysical phenomena; to forecast the original signal. Various examples of application of these methods are exhibited on radon time series collected in some Italian sites, in order to make a retrospective analysis to better study the existing correlation between anomalies and earthquakes. The results obtained from this study highlight the manifold capabilities of the proposed methods in the radon signal analysis, exploitable also for any kind of research framework that needs data analysis of time series
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