Salt weathering of limestones: susceptibility of petrographical features (SEM study)

Fundação para a Ciência e a Tecnologia (FCT) - Verbas nacionais e FEDE

Mass spectrometry improvement on an high current ion implanter

The development of accurate mass spectrometry, enabling the identification of all the ions extracted from the ion source in a high current implanter is described. The spectrometry system uses two signals (x-y graphic), one proportional to the magnetic field (x-axes), taken from the high-voltage potential with an optic fiber system, and the other proportional to the beam current intensity (y-axes), taken from a beam-stop. The ion beam mass register in a mass spectrum of all the elements magnetically analyzed with the same radius and defined by a pair of analyzing slits as a function of their beam intensity is presented. The developed system uses a PC to control the displaying of the extracted beam mass spectrum, and also recording of all data acquired for posterior analysis. The operator uses a LabView code that enables the interfacing between an I/O board and the ion implanter. The experimental results from an ion implantation experiment are shown. (C) 2011 Elsevier B.V. All rights reserved

Performance of stones under different conditions : a study of metro stations

The study of stone alterations in the Lisbon Metro stations allowed the discussion of the influence in the development of these alterations of stones characteristics and the actual conditions to which the stones are subjected. Alterations occur under what can be considered the usual conditions of use but also under abnormal situations that must be taken into account given its frequency. The diverse situations identified are considered in the discussion of possible recommendations bearing in mind the actual situations found at the stations.Financiado pela Fundação para a Ciência e a Tecnologia com fundos nacionais (programa plurianual de financiamento de unidades de investigação)

Estimating home-range size: when to include a third dimension?

Most studies dealing with home ranges consider the study areas as if they were totally flat, working only in two dimensions, when in reality they are irregular surfaces displayed in three dimensions. By disregarding the third dimension (i.e., topography), the size of home ranges underestimates the surface actually occupied by the animal, potentially leading to misinterpretations of the animals' ecological needs. We explored the influence of considering the third dimension in the estimation of home-range size by modeling the variation between the planimetric and topographic estimates at several spatial scales. Our results revealed that planimetric approaches underestimate home-range size estimations, which range from nearly zero up to 22%. The difference between planimetric and topographic estimates of home-ranges sizes produced highly robust models using the average slope as the sole independent factor. Moreover, our models suggest that planimetric estimates in areas with an average slope of 16.3° (±0.4) or more will incur in errors ≥5%. Alternatively, the altitudinal range can be used as an indicator of the need to include topography in home-range estimates. Our results confirmed that home-range estimates could be significantly biased when topography is disregarded. We suggest that study areas where home-range studies will be performed should firstly be scoped for its altitudinal range, which can serve as an indicator for the need for posterior use of average slope values to model the surface area used and/or available for the studied animals.This work was partially supported by a research project from the Spanish National Plan (project ref: CGL2009-10741) funded by the Spanish Ministry of Science and Innovation and EU-FEDER funds. P. M. was supported by a Ph.D. grant from the Fundaçao para a Ciència e a Tecnologia (FCT) (SFRH/BD/37795/2007). N. S. was partially supported by a postdoctoral grant from FCT (SFRH/BPD/26666/2006). L. M. R. was funded by a Postdoctoral fellowship from the FCT and Fundo Social Europeu (III Quadro Comunitario de Apoio) (SFRH/BPD/35842/2007) and FAPESP (Proc. Ref.: 2011/00408-4).Peer Reviewe

Performance of stones under different conditions: a study of metro stations

Fundação para a Ciência e a Tecnologia (FCT

Arduino-controlled Reflectance Transformation Imaging to the study of cultural heritage objects

Fundacao para a Ciencia e a Tecnologia, Portugal (Grant Nos. UIDB/04349/2020 and UID/FIS/04559/2019)- Private funds. V.C. acknowledges the support from UID/Multi/04349/2019. J.C. acknowledges NOVA.ID.FCT.This article examines the development of a low-cost and portable set-up controlled by an Arduino board to perform Reflectance Transformation Imaging technique, from the information derived from 45 digital photographs of an object acquired using a stationary camera. The set-up consists of 45 high-intensity light emitting diodes (LEDs) distributed over a hemispherical dome of 70 cm in diameter and a digital camera on the top of the dome. The LEDs are controlled by an Arduino board, and the user can individually control the LEDs state (ON or OFF) and duration of illumination. An old manuscript written with iron-gall ink and a set of 1 Euro coins mint in 2002 were photographed with the set-up. The interactive re-lighting and the mathematical enhancement of the object's surface revealed corrosion, loss of material, scratches and other details, which were not perceived in standard images. These unique features, which can be extracted using edge detection processing, have immediate application in different fields such as cultural heritage or forensic studies, where they can be used as fingerprints to identify unique objects, allowing also recognizing the use of tools to alter the surface of coins to increase the price in the market.publishersversionpublishe

Nanotechnology in Roman Opaque Red Glass from the 2nd Century AD. Archaeometric Investigation in Red Sectilia from the Decoration of the Lucius Verus Villa in Rome

PD/BD/135053/2017 UID/EAT/00729/2019This work aims to characterise the chemical composition of Roman opaque red glass sectilia dated to the 2nd century A.D and to shed light on Roman glassmaking production of different shades of red, from red to reddish-brown. Due to the lack of technical historical sources for this period many questions about technological aspects still remain. In this project a multi-disciplinary approach is in progress to investigate the red glass sectilia with several red hues from the Imperial Villa of Lucius Verus (161–169 A.D.) in Rome. First, colorimetric measurements were taken to identify the various red hues. The second step was chemical characterization of the samples and the identification of crystalline colouring phases. Particle Induced X-Ray Emission (PIXE) analysis was used to investigate the chemical composition of these glass samples, while the crystalline phases were identified by Raman Spectroscopy and Scanning Electrons Microscope with Energy Dispersive X-ray Spectrometry (SEM-EDS). Using SEM-EDS nanoparticles were detected as a colouring agent, the chemical composition and the morphology of which has been studied in depth. This information has been compared with the colorimetric analysis to establish any correlation with the different colour hues.publishersversionpublishe

MF Calculator: A Web-Based Application for Analyzing Similarity

This paper presents the metric-frequency calculator (MF Calculator), an online application to analyze similarity. The MF Calculator implements a metric-frequency similarity algorithm for the quantitative assessment of similarity in ill-structured data sets. It is widely applicable as it can be used with nominal, ordinal, or interval data when there is little prior control over the variables to be observed regarding number or content. The MF Calculator generates a proximity matrix in CSV, XML or DOC format that can be used as input to traditional statistical techniques such as hierarchical clustering, additive trees, or multidimensional scaling. The MF Calculator also displays a graphical representation of outputs using additive similarity trees. A simulated example illustrates the implementation of the MF calculator. An additional example with real data is presented, in order to illustrate the potential of combining the MF Calculator with cluster analysis. The MF Calculator is a user-friendly tool available free of charge. It can be accessed from http : //mfcalculator.celiasales.org/Calculator.aspx, and it can be used by non-experts from a wide range of social sciences.info:eu-repo/semantics/publishedVersio

18F-FDG measurement in primary lung cancer: SUV normalization to different distribution volumes

Introduction: Standard Uptake Value (SUV) is a measurement of the uptake in a tumour normalized on the basis of a distribution volume and is used to quantify 18F-Fluorodeoxiglucose (FDG) uptake in tumors, such as primary lung tumor. Several sources of error can affect its accuracy. Normalization can be based on body weight, body surface area (BSA) and lean body mass (LBM). The aim of this study is to compare the influence of 3 normalization volumes in the calculation of SUV: body weight (SUVW), BSA (SUVBSA) and LBM (SUVLBM), with and without glucose correction, in patients with known primary lung tumor. The correlation between SUV and weight, height, blood glucose level, injected activity and time between injection and image acquisition is evaluated. Methods: Sample included 30 subjects (8 female and 22 male) with primary lung tumor, with clinical indication for 18F-FDG Positron Emission Tomography (PET). Images were acquired on a Siemens Biography according to the department’s protocol. Maximum pixel SUVW was obtained for abnormal uptake focus through semiautomatic VOI with Quantification 3D isocontour (threshold 2.5). The concentration of radioactivity (kBq/ml) was obtained from SUVW, SUVBSA, SUVLBM and the glucose corrected SUV were mathematically obtained. Results: Statistically significant differences between SUVW, SUVBSA and SUVLBM and between SUVWgluc, SUVBSAgluc and SUVLBMgluc were observed (p=0.000<0.05). The blood glucose level showed significant positive correlations with SUVW (r=0.371; p=0.043) and SUVLBM (r=0.389; p=0.034). SUVBSA showed independence of variations with the blood glucose level. Conclusion: The measurement of a radiopharmaceutical tumor uptake normalized on the basis of different distribution volumes is still variable. Further investigation on this subject is recommended

Swiss stained-glass panels: an analytical study

The history and iconography of Swiss stained glass dating between the 16th and 18th centuries are well studied. However, the chemical and morphological characteristics of the glass and glass paints, particularly the nature of the raw materials, the provenance of the glass, and the technology used to produce it are less well understood. In this paper, we studied two sets of samples from stained-glass panels attributed to Switzerland, which date from the 16th to 17th centuries: the first set comes from Pena National Palace collection, the second from Vitrocentre Romont. The aims were to identify the materials used in the production of the glass, to find out more about their production origin and to characterize the glass paints. Both glass and the glass paints were analysed by particle-induced X-ray emission; the paints were additionally analysed by scanning electron microscopy–electron-dispersive X-ray spectroscopy (SEM-EDS). The results show that the glass from both sets was probably produced in the same region and that wood ash was used as a fluxing agent. Different recipes have been used to make the blue enamels. However, the cobalt ore used as a coloring agent in all of the blue enamels came from the mining district in Schneeberg, Germany