1,721,192 research outputs found
Spectroscopic considerations on DIAL measurement of carbon dioxide in volcanic emissions
No full textThe true magnitude of CO2 emissions from volcanic activity is poorly constrained, limiting our understanding of the natural carbon cycle. CO2-sensitive lidars could be used to measure the distribution of CO2 in a volcanic plume, thereby allowing volcanic CO2 fluxes to be measured directly. The recently-begun ERC research project CO2VOLC aims to produce such an instrument based on the differential absorption lidar (DIAL) technique. In this paper we investigate the ON and OFF wavelengths which offer optimal CO2 detection and identify the spectral requirements of the lidar transmitter, in the context of commercially available solid-state laser sources
High resolution spectroscopy of sweeteners
No full textThe identification of sophistication in beverage and food products has an increasing role in modern society. Different techniques are currently used for qualitative assessment of food stuff and beverages. Among them high resolution spectroscopy shown to be able to identify different types of sweeteners such as fructose, glucose, maltose, sucrose and aspartame. To this purpose, a reliable, fast and easy-to-use screening method for the optical characterization of these substances was developed. In the present work the Infrared Laser Photo-Acoustic Spectroscopy was used to record high resolution infrared absorption spectra of common sugars in the fingerprint region, not previously reported in literature at our knowledge. Spectral data were obtained by a CO2 laser based optical apparatus. These preliminary results are the key toward a further analysis of sweeteners in a complex matrix devoted to detecting adulteration of commercial fruit juices and light drinks by low cost sweeteners
Spettroscopia ad alta risoluzione di zuccheri
Full text linkUn sensore IR basato su spettroscopia laser fotoacustica (LPAS) realizzato al Centro ENEA di Frascati, sulla base di una sorgente laser CO2, è stato applicato alla rivelazione ad alta risoluzione degli spettri di assorbimento di comuni sostanze dolcificanti nella regione fingerprint. Vengono descritti metodo e risultati sperimentali. A nostra conoscenza, i dati spettrali ottenuti con tecnica LPAS per il fruttosio, glucosio, maltosio e saccarosio non sono stati precedentemente riportati dalla letteratura scientifica.A Infrared Laser Photo-Acoustic Spectroscopy (LPAS) sensor realised at ENEA Frascati Center, based on a CO2 laser source, was applied for recording high resolution absorption spectra of common sugars in the fingerprint region. The methods and the experiments are described; the results are reported. The spectral data obtained by the LPAS sensor for fructose, glucose, maltose and sucrose were not previously reported in literature at our knowledge
Investigation of Plant–Pathogen Interaction by Laser-Based Photoacoustic Spectroscopy
No full textThe CO2laser-based photoacoustic spectroscopy apparatus, constructed at ENEA Frascati (Italy), was applied to monitor trace amounts of ethylene emitted by plants in a stress condition. More specifically, in the present work, the biotic stress response of tomato mutant plants after inoculation with Phthorimaea operculella larvae (Lepidoptera: Gelechiidae) was investigated. The principle of the method, the photoacoustic setup, the experimental work, and the results are being reported
Spectroscopic study of some IED's precursors by means of laser photoacoustic spectroscopy combined with multivariate analysis
No full textThe Improvised Explosive Device (IED) is the most prevalent form of explosive device utilized by terrorists today being easy to realize and difficult to detect. These explosive devices are made by mixing different precursor substances that are generally cheap and commercially available. Thus, attention should be focused on developing fast and reliable methods able to identify such substances. In this paper we applied laser photoacoustic spectroscopy method for the spectral characterization and identification of a number of common chemicals used as precursors of IEDs: potassium sulfate, potassium nitrate, magnesium sulfate, ammonium perchlorate, ammonium nitrate, and acetone. The analyzed chemical species were classified by Principal Component Analysis applied to the collected spectral data. As conclusion of the study, the laser photoacoustic spectroscopy combined with chemometrics has confirmed to be a useful tool that could support the fight against the increased realization of modern bombs for criminal use
Application of laser photoacoustic spectroscopy and chemometrics in homeland security
No full textIn the last decades, the military and Government organizations have an increasing interest in development of field-sensors for homeland security issues. In order to detect explosives (such as DNT, TNT, tetryl, RDX, HMX, TATP, PETN) and some precursors of Improvised Explosive Devices (i.e. potassium sulfate, potassium nitrate, magnesium sulfate, ammonium perchlorate, ammonium nitrate, acetone), we applied laser photoacoustic spectroscopy (LPAS) and a chemometric method (PCA, Principal Component Analysis) to speed up the identification process. The results indicated that the combination of LPAS and PCA is very useful for a rapid identification of these chemicals. © Springer International Publishing Switzerland 2016
QCL based photoacoustic spectometer for food safety
Full text linkIl Laboratorio Diagnostiche e Metrologia (FSN-TECFIS-DIM) dell’Agenzia Nazionale per le Nuove Tecnologie, l’Energia e lo Sviluppo Economico Sostenibile (ENEA) ha applicato da anni la spettroscopia fotoacustica con laser CO2 alla sicurezza alimentare. Allo scopo di rendere disponibili alle autorità di controllo uno strumento portatile e di facile utilizzo, sono necessari laser più piccoli e controlli automatici. Questo rapporto presenta un nuovo strumento, basato su una sorgente QCL, in cui ogni misura è completamente gestita da un software dedicato. Quindi, alcune caratterizzazioni dell’intero sistema e delle sue componenti sono fornite. Alla fine, i suoi primi risultati nel quadro del progetto Metrofood
sono brevemente descritti.The Diagnostics and Metrology Laboratory (FSN-TECFIS-DIM) of the Italian National Agency for New Technologies, Energy and Sustainable Economic Development (ENEA) applied for years photoacoustic spectroscopy with CO2 lasers to food safety. In order to make available to control authorities a portable and user-friendly instrument, smaller lasers and automated controls are necessary. This report presents a new instrument, based on a QCL source, in which each measurement is fully managed by a dedicated software. Then, some characterizations of the whole system and its components are provided. Finally, its first results in the framework of the Metrofood project are briefly described
Red color characterization in several Roman frescos and paintings by in situ and remote LIBS, LIF and Raman Spectroscopies
Full text linkNowadays, in situ pigments characterization on a cultural heritage relevant surface is possible by using combined laser spectroscopies which are suitable to detect at high resolution both molecular (Raman, LIF) and atomic sample composition (LIBS), the latter with stratigraphic capabilities and high sensitivity for trace detection. Their applications are here reported regarding the identification of historical pigments and dyes on different substrates, particularly in wall paintings, from pre-historic times up to the XIXth century when the use of synthetic substances became common. In this paper attention is focused on red colors, known since antiquity for the additional ritual and medical use. Their pictorial use along the centuries is shown and in selected cases provenances hypothesis, based on historical information, could be supported by results of composition analysis and elemental trace detection made possible by the application of laser technologies
LIF/Raman/XRF non-invasive microanalysis of frescoes from St. Alexander catacombs in Rome
No full textLaser-induced fluorescence (LIF), Raman spectroscopy and X-ray (XRF) fluorescence were used to study two frescoes at the S. Alexander catacombs complex, in Rome. LIF analysis has shown the presence of a transparent protective material probably deposited in previous restoration treatments and allowed to clearly distinguish the areas undergoing the current restoration process from the ones which still have to be treated. Raman and XRF analysis allowed to non-destructively characterizing most of the pictorial materials used for the artworks, including calcite (CaCO3), red ochre (Fe2O3), minium (Pb3O4), yellow ochre (α-FeOOH) and others. Therefore, thanks to the complementarity of the above-mentioned techniques, it was possible to obtain a detailed characterization of the studied frescoes. Finally, the whole ensemble of results constituted a valid tool to effectively plan the restoration of the frescoes. © 2018 Elsevier B.V
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