Search results for "Libs"

Latvijas atradņu dzelzsrūdu sastāva noteikšana

2022

Latvijas atradņu dzelzsrūdu sastāva noteikšana. Vorobjovs D., zinātniskie vadītāji: prof., Dr. chem. Vīksna A. un asoc. prof., Dr. geol. Stinkulis Ģ. Bakalaura darbs, 62 lappuses, 35 attēli, 7 tabulas, 45 literatūrās avoti, 2 pielikumi. Latviešu valodā. Bakalaura darba ietvaros veica kvalitatīvo (mineraloģisko) dzelzsrūdu paraugu analīzi laboratorijas apstākļos, izmantojot pulvera rentgendifraktometrijas (XRD) metodi, ka arī tika izmantota rentgenstaru fluorescence (XRF) un lāzera inducētas sadalīšanās spektroskopija (LIBS) rūdu kvantitatīvā ķīmiskā sastāva noteikšanai.

Studio integrato per la caratterizzazione dei laterizi

2008

Metodologie spettroscopiche integrate per la caratterizzazione dei prodotti di corrosione nei bronzi archeologici

2010

LIBS analysis for a stratigraphic study on Cultural Heritage material

2015

Study of Toner Penetration in Papers by Laser Induced Plasma Spectroscopy and Optical Profilometry

2023

Four major toners are used in the printing industry, cyan, magenta, yellow and black (Key) for making color images on paper. Paper brands suitable for printing have thin mineral/latex coatings, and toners are applied on top of the coating in the printing process. Chemical compositions from toner to toner, as well as from coating to coating, vary according to the needs of the end user. Interactions between the toner and the coating define the final color formation of the images in printing. Hence, it is important to study characteristics and dynamics of toners on coated papers. In this paper, we have used laser-induced plasma spectroscopy (LIBS) to provide information on elemental distributi…

Time‐gated Raman and laser‐induced breakdown spectroscopy in mapping of eudialyte and catapleiite

2019

Abstract Raman analysis of rock samples containing rare earth elements (REEs) is challenging due to the strong fluorescence, which may mask the weaker Raman signal. In this research, time‐gated (TG) Raman has been applied to the construction of the mineral distribution map from REE‐bearing rock. With TG Raman, material is excited with a short subnanosecond laser pulse, and the Raman signal is collected within a picosecond‐scale time window prior to the formation of a strong fluorescent signal by means of single‐photon avalanche diode array. This allows signal readout with a significantly reduced fluorescence background. TG Raman maps are used to reveal the location of valuable minerals and …

Detection of deuterium retention by LIBS at different background pressures

2017

ITER plans foresee the quantitative diagnostics of fuel retention in reactor walls at near-atmospheric pressures. Using laser induced breakdown spectroscopy (LIBS) for this purpose assumes a reliable resolving of Balmer α-lines of hydrogen isotopes in spectra of plasma produced by focused laser radiation onto the target surface. To develop LIBS for quantitative diagnostics of fuel retention during the maintenance breaks of ITER, the effect of background gas pressure on the laser-induced plasma characteristics has been studied. The background pressure limits the expansion rate of plasma and as a result it leads to higher plasma concentrations. At the same time the limiting factor of the reso…

Integrated analytical methodologies for the study of corrosion processes in archaeological bronzes

2011

Abstract The investigations on structure and micro-chemical composition of archaeological metal alloys are needed in archaeometry. The aim of this study is devoted both to acquire information about their provenance and production technology, and to improve our understanding about the corrosion processes. In this paper we present the study of the corrosion phenomena of bronze samples, laboratory-made according to binary, ternary and quaternary alloys typical of Roman archaeometallurgical production through an integrated methodology based on the use of non or micro invasive physical techniques. Among the analysed samples, two were artificially aged through burial in the archaeological site of…

Optimization of spodumene identification by statistical approach for laser-induced breakdown spectroscopy data of lithium pegmatite ores

2021

Mapping with laser-induced breakdown spectroscopy (LIBS) can offer more than just the spatial distribution of elements: the rich spectral information also enables mineral recognition. In the present study, statistical approaches were used for the recognition of the spodumene from lithium pegmatite ores. A broad spectral range (280–820 nm) with multiple lines was first used to establish the methods based on vertex component analysis (VCA) and K-means and DBSCAN clusterings. However, with a view to potential on-site applications, the dimensions of the datasets must be reduced in order to accomplish fast analysis. Therefore, the capability of the methods in mineral identification was tested wi…

Singular value decomposition approach to the yttrium occurrence in mineral maps of rare earth element ores using laser-induced breakdown spectroscopy

2017

Laser-induced breakdown spectroscopy (LIBS) has been used in analysis of rare earth element (REE) ores from the geological formation of Norra Kärr Alkaline Complex in southern Sweden. Yttrium has been detected in eudialyte (Na15 Ca6(Fe,Mn)3 Zr3Si(Si25O73)(O,OH,H2O)3 (OH,Cl)2) and catapleiite (Ca/Na2ZrSi3O9·2H2O). Singular value decomposition (SVD) has been employed in classification of the minerals in the rock samples and maps representing the mineralogy in the sampled area have been constructed. Based on the SVD classification the percentage of the yttrium-bearing ore minerals can be calculated even in fine-grained rock samples. peerReviewed