1,721,001 research outputs found
Theretical and practical approach in determining matrix effects in quantitative XRF analysis
No full textanalysis of rocks by XRF. These effects can be corrected by using ap-
propriate experimental or calculated algorythms, starting from a set of
reference samples using multivariate regression methods.
In this work, we propose a simple method to evaluate the expected
matrix effects for major elements, on the basis of the XRF total mass
attenuation coefficients available in the literature.
The obtained results confirm that theoretically calculated matrix ef-
fects are compatible with those experimentally observed.
The proposed method makes it easier to choose an appropriate cali-
bration set for routine analysis, allowing for a reduction in the number
of standards to be used, or in case it is necessary to activate a new
analytical line
Quantitative phase analyses on Portland cement by rietveld method
No full textQuantitative phase analyses (QPA) on a series of industrial Portland cements were performed using the Rietveld methods. The results were compared to those obtained from Bogue calculation in order to assess (if any) the correlations between this two techniques. In agreement with other recent reports, it appears that relationships having a general validity cannot be established. This finding reinforces the conclusion that the Rietveld method should be regarded as the most versatile and reliable technique for QPA of Portland cements
Dati preliminari sulla "cristallinità" dell'illite in alcune formazioni della successione umbro-marchigiana (Appennino centrale)
No full text
Macigno sandstone from Monti d’Oltre Serchio: Chemical, mineralogical, petrographic and physical characterization of a building material
No full textThe sandstones of the Macigno Formation have been widely used in Tuscany as a building material since Roman times and even earlier by the Etruscans. In this work, we focus on the Macigno sandstone of the Monti d'Oltre Serchio, on its physical properties and on its chemical, mineralogical and petrographic characteristics
The building stones of Pienza (Tuscany, Italy)
No full textPienza, a fifteenth-century town in Tuscany, Italy, is renowned as a prime example of Renaissance urbanism. Constructed by Pope Pius II, the town was designed by the esteemed architect Bernardo Rossellino to embody an ideal city centered around a grand square, Piazza Pio II. This study focuses on
identifying and characterizing the stones used in Pienza's main buildings and understanding their decay forms. Through XRF and XRD analyses, the chemical and mineralogical characteristics of the main
identified litologies (Pienza sandstones and Bioclastic calcirudites) have been determined. Microscopic observations aided in studying thin sections, while physical and mechanical properties of the stones
were also assessed. The findings have led to the proposal of an geo-lithological itinerary to showcase the building stones of the most remarkable monuments and palaces of the Pienza center, and highlight the locations of their quarrying areas. This research aims to contribute to the knowledge and valorization of Pienza's architectural heritage
Relationships among tectonic deformation in foreland fold&thrust belts, clay mineralogy and vitrinite reflectance data: a case history from the Central Apennines (Italy)
No full textGoing Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
- …
