Search results for "MINERALOGY"

A new method in investigations of bubble cluster shapes in two-phase flow

1991

Abstract In this paper a new probabilistic method is used to analyse the distribution of air bubbles in two-phase flow. So far, the method has been applied in astronomy and cosmology to investigate the distribution of galaxies. The basic idea is presented and the method applied to the photographed population of air bubbles in a liquid. The method allows the homogeneity of the flow to be evaluated qualitatively and quantitatively.

The pigment in red beds — a geologic thermometer

1969

The Maya Blue Pigment

2011

Abstract Maya blue is an artificial pigment fabricated by the Maya in the early first millennium AD. The pigment was used in Prehispanic times from the southern Maya region to most Mesoamerican cultures. Maya blue is made from indigotin mixed with palygorskite. This light blue pigment is surprisingly resistant to degradation in adverse environmental conditions, as it is unaffected by the attack of acids, alkalis, oxidants, reducing agents and organic solvents. Scientists do not fully agree in the mechanism of this organoclay interaction. The fabrication and distribution of this pigment probably required a sophisticated technical and commercial infrastructure. This chapter reviews the presen…

A Unique Collection of Palaeolithic Painted Portable Art: Characterization of Red and Yellow Pigments from the Parpalló Cave (Spain).

2016

In this work we analyze the pigments used in the decoration of red and yellow motifs present in the portable art of the Parpallo Cave (Gandia, Spain), one of the most important Palaeolithic sites in the Spanish Mediterranean region. Energy dispersive X-ray fluorescence spectrometry (EDXRF) and spectrophotometry in the visible region (CIEL*a*b*color coordinates and spectral reflectance curves) were used to perform in situ fast analyses of the red and yellow motifs with portable equipment and to characterize their elemental composition and their colorimetric perception, respectively. According to the elemental composition, the intensity of the fluorescence iron signals in red and yellow motif…

Environmental impact of magmatic fluorine emission in the Mt. Etna area

2007

-UniversitA degli Studi di Palermo, Italy -Istituto Nazionale di Geofisica e Vulcanologia, Sezione di Palermo - Unione Europea, Fondo Sociale Europeo

Microstructural evolution and growth of crystallite size of mullite during thermal transformation of kyanite

1997

Abstract The microstructural evolution of mullite during the thermal transformation of kyanite has been studied in the temperature range 1200–1600 °C. The shape and size of the grains were analysed by means of SEM-EDS while crystallite size evolution was studied by X-ray line profile analyses. The results obtained showed that total transformation of kyanite to mullite takes place between 1350 and 1400 °C. At temperatures below 1350 °C needle-like mullite grains are always produced. At higher temperatures the mullite grains reveal rounded end platelet morphology. Evolution from needle-like to platelet shape was correlated with the X-ray data.

An evaluation of inoceramid single-prism sclerochronology

2020

Abstract Inoceramid prisms are among the most common microfossils that can be found in Late Cretaceous strata. Since these biomineral units were formed by sequential accretion in the outer shell layer of the bivalves, they potentially serve as archives of short-term (circa-annual) paleowater temperature fluctuations. In the present study, we tested to what extent intra-prismatic stable isotope variations of individual inoceramid prisms reflect sub-annual δ13C and the δ18O patterns. We obtained multiple carbonate samples from prisms recovered from the sediment and from a cross-sectioned inoceramid shell fragment and compared data from these samples to data from classical sclerochronological …

X-ray CT analyses, models and numerical simulations: a comparison with petrophysical analyses in an experimental CO<sub>2</sub&a…

2016

Abstract. An essential part of the collaborative research project H2STORE (hydrogen to store), which is funded by the German government, was a comparison of various analytical methods for characterizing reservoir sandstones from different stratigraphic units. In this context Permian, Triassic and Tertiary reservoir sandstones were analysed. Rock core materials, provided by RWE Gasspeicher GmbH (Dortmund, Germany), GDF Suez E&P Deutschland GmbH (Lingen, Germany), E.ON Gas Storage GmbH (Essen, Germany) and RAG Rohöl-Aufsuchungs Aktiengesellschaft (Vienna, Austria), were processed by different laboratory techniques; thin sections were prepared, rock fragments were crushed and cubes of …

Electrochemistry of iron oxide pigments (earths) from pictorial microsamples attached to graphite–polyester composite electrodes

2001

The electrochemical response of different iron pigments attached to graphite–polyester composite electrodes is described. Characteristic differential pulse voltammetric profiles were obtained for green earth, iron oxide red, Mars black, ochre yellow, Sienna raw, umber raw and Van Dyke brown. Proton-assisted reductive dissolution processes occur at the three-phase boundary of the substrate electrode–attached solid–electrolyte solution system. Microsamples extracted from polychromed sculptures, canvas paintings, wall paintings, altarpieces and panel paintings from Spain, Ethiopia and Italy from the 12th to the 20th centuries were electrochemically identified in agreement with polarized light …

Traffic-related pollutants in roadside soils of different countries in Europe and Asia

2015

We investigated the magnetic and chemical properties of the roadside soil samples collected from five European and Asian countries. Spots in which cars slowed down and/or accelerated due to the traffic organization (speed limits, junctions, and traffic lights) were selected for sampling. Apart from the Zabrze site (Poland), the magnetic susceptibility and heavy metal contents decreased with increasing distance from the road edge. The highest mass-specific magnetic susceptibility values (χ) were observed in the samples collected from Mumbai (India) and Zabrze (Poland). Moreover, the high contents of Fe, Ni, Mn, and Co were observed in Mumbai, whereas in Zabrze, all the examined elements demo…