scholarly journals X-ray Micro-Tomography as a Method to Distinguish and Characterize Natural and Cultivated Pearls

2021 ◽  
Vol 6 (4) ◽  
pp. 51
Author(s):  
Luisa Vigorelli ◽  
Elisabetta Croce ◽  
Debora Angelici ◽  
Raffaella Navone ◽  
Sabrina Grassini ◽  
...  
Keyword(s):  
Diagnostic Techniques ◽  
X Ray ◽  
Non Invasive ◽  
Heritage Studies ◽  
Different Types ◽  
Micro Tomography ◽  
Invasive Techniques ◽  
Tomographic Analysis ◽  
Private Collections

Digital radiography and computed tomography are two fundamental diagnostic techniques in different fields of research, including cultural heritage studies and gemmology. The application of these physical methods of investigation has gained considerable importance as they are non-invasive techniques. The presented work has been mainly focused on micro-tomographic analysis. The project is concerned with the study of natural and cultivated pearls in order to develop an investigation methodology for the analysis, distinction and characterization of different types of pearls, some of them belonging to different precious jewels from private collections. The investigations, carried out on a total of 22 heterogeneous types of pearls, allowed us to establish their origin (natural or cultivated) or to confirm/deny if a hypothesis was already expressed, and as well to highlight the cultivation methodology used case by case. Furthermore, it was possible to ascertain how large and varied the market for cultured pearls is nowadays and how difficult is, in some particular cases, to ascertain their attribution to a certain origin.

scholarly journals Brightly Colored to Stay in the Dark. Revealing of the Polychromy of the Lot Sarcophagus in the Catacomb of San Sebastiano in Rome

Heritage ◽  
2020 ◽  
Vol 3 (3) ◽  
pp. 858-874
Author(s):  
Susanna Bracci ◽  
Donata Magrini ◽  
Rachele Manganelli del Fà ◽  
Oana Adriana Cuzman ◽  
Barbara Mazzei
Keyword(s):  
Late Antiquity ◽  
3D Model ◽  
Non Invasive ◽  
Naked Eye ◽  
Executive Process ◽  
Different Types ◽  
Yellow Ochre ◽  
Invasive Techniques

The Lot Sarcophagus is one of the most relevant funerary sculptures of late antiquity (mid-4th century AC). Some of the remarkable aspects are the following (i) it is still preserved in situ; (ii) most of the carved scenes are rarities or unicum; (iii) not all the sculpture work has been completed, which allows us to analyse the executive process; (iv) many traces of polychromy have remained. This paper is focused on the characterization of the residual polychromy by using in-situ non-invasive techniques. Furthermore, few micro samples were taken, to be analysed in laboratory to study the composition of some deposits and to define if a preparatory layer was present under the coloured layer. The data showed that the very rich polychromy of the Lot Sarcophagus was made of Egyptian blue, yellow ochre, and three different types of red: two inorganics (red ochre and cinnabar), and one organic-based (madder lake). Furthermore, some decorations, completely vanished and no longer visible to the naked eye, have been rediscovered, also providing details on the construction phases. During the project, the 3D model of the sarcophagus was acquired, which afterwards was used to map the results of the diagnostic campaign.

Stochastic Modeling of Multidimensional Particle Properties Using Parametric Copulas

2019 ◽  
Vol 25 (3) ◽  
pp. 720-734 ◽  
Author(s):  
Orkun Furat ◽  
Thomas Leißner ◽  
Kai Bachmann ◽  
Jens Gutzmer ◽  
Urs Peuker ◽  
...  
Keyword(s):  
Prediction Models ◽  
Image Data ◽  
Archimedean Copulas ◽  
Mineralogical Characterization ◽  
X Ray ◽  
Particle Properties ◽  
Particle Characteristics ◽  
Different Types ◽  
Micro Tomography

AbstractIn this paper, prediction models are proposed which allow the mineralogical characterization of particle systems observed by X-ray micro tomography (XMT). The models are calibrated using 2D image data obtained by a combination of scanning electron microscopy and energy dispersive X-ray spectroscopy in a planar cross-section of the XMT data. To reliably distinguish between different minerals the models are based on multidimensional distributions of certain particle characteristics describing, for example, their size, shape, and texture. These multidimensional distributions are modeled using parametric Archimedean copulas which are able to describe the correlation structure of complex multidimensional distributions with only a few parameters. Furthermore, dimension reduction of the multidimensional vectors of particle characteristics is utilized to make non-parametric approaches such as the computation of distributions via kernel density estimation viable. With the help of such distributions the proposed prediction models are able to distinguish between different types of particles among the entire XMT image.

scholarly journals How Many Secret Details Could a Systematic Multi-Analytical Study Reveal About the Mysterious Fresco Trionfo della Morte?

Heritage ◽  
2019 ◽  
Vol 2 (3) ◽  
pp. 2370-2383
Author(s):  
Alberghina ◽  
Schiavone ◽  
Greco ◽  
Saladino ◽  
Armetta ◽  
...  
Keyword(s):  
Ir Spectroscopy ◽  
Analytical Study ◽  
Multispectral Imaging ◽  
Imaging Analysis ◽  
X Ray ◽  
Small Areas ◽  
Non Invasive ◽  
History Of ◽  
Invasive Techniques

The “Trionfo della morte” is a detached fresco painting dated at the half of the XV century. Its history is strictly connected with the history of Palermo and it is considered a symbol of the late Gothic period. Some small areas of the fresco were analyzed using a combination of non-invasive techniques and hand-held instrumentations (multispectral imaging analysis, X-ray fluorescence (XRF), and IR spectroscopy). The characterization of the nature of pigments used in its realization and restoration works was performed and some indications about its conservation state were obtained. More interestingly, some hidden details were revealed on the mysterious painting. They constitute additional evidence of the preciousness of the fresco.

scholarly journals Synthesis and Characterization of Clay Polymer Nanocomposites of P(4VP-co-AAm) and Their Application for the Removal of Atrazine

Polymers ◽  
2019 ◽  
Vol 11 (4) ◽  
pp. 721 ◽  
Author(s):  
Jorge A. Ramírez-Gómez ◽  
Javier Illescas ◽  
María del Carmen Díaz-Nava ◽  
Claudia Muro-Urista ◽  
Sonia Martínez-Gallegos ◽  
...  
Keyword(s):  
Polymer Nanocomposites ◽  
Nanocomposite Materials ◽  
Synthesis And Characterization ◽  
Cross Linking ◽  
X Ray Diffraction ◽  
Numerous Species ◽  
X Ray ◽  
Different Types ◽  
Synthesized Materials

Atrazine (ATZ) is an herbicide which is applied to the soil, and its mechanism of action involves the inhibition of photosynthesis. One of its main functions is to control the appearance of weeds in crops, primarily in corn, sorghum, sugar cane, and wheat; however, it is very toxic for numerous species, including humans. Therefore, this work deals with the adsorption of ATZ from aqueous solutions using nanocomposite materials, synthesized with two different types of organo-modified clays. Those were obtained by the free radical polymerization of 4-vinylpyridine (4VP) and acrylamide (AAm) in different stoichiometric ratios, using tetrabutylphosphonium persulfate (TBPPS) as a radical initiator and N,N′-methylenebisacrylamide (BIS) as cross-linking agent. The structural, morphological, and textural characteristics of clays, copolymers, and nanocomposites were determined through different analytical and instrumental techniques, i.e., X-ray diffraction (XRD), Fourier-transform infrared spectroscopy (FTIR), and thermogravimetric analysis (TGA). Adsorption kinetics experiments of ATZ were determined with the modified and synthesized materials, and the effect of the ratio between 4VP and AAm moieties on the removal capacities of the obtained nanocomposites was evaluated. Finally, from these sets of experiments, it was demonstrated that the synthesized nanocomposites with higher molar fractions of 4VP obtained the highest removal percentages of ATZ.

Characterization of oil nano-structures with monochromatic x-ray micro-tomography

2012 ◽  
Author(s):  
Victor E. Asadchikov ◽  
Alexey V. Buzmakov ◽  
Anna S. Osadchaya ◽  
Denis A. Zolotov ◽  
Michael K. Rafailov
Keyword(s):  
X Ray ◽  
Nano Structures ◽  
Micro Tomography

Calcium oxalate crystal distribution in rose peduncles: Non-invasive analysis by synchrotron X-ray micro-tomography

2012 ◽  
Vol 72 ◽  
pp. 27-34 ◽  
Author(s):  
Uzuki Matsushima ◽  
André Hilger ◽  
Wolfgang Graf ◽  
Simon Zabler ◽  
Ingo Manke ◽  
...  
Keyword(s):  
Calcium Oxalate ◽  
Calcium Oxalate Crystal ◽  
X Ray ◽  
Non Invasive ◽  
Micro Tomography

scholarly journals Progress of non-invasive diagnostic of liver fibrosis: review of modern laboratory methods

2020 ◽  
pp. 224-232
Author(s):  
E. A. Kulebina ◽  
A. N. Surkov
Keyword(s):  
Liver Fibrosis ◽  
Gold Standard ◽  
Diagnostic Techniques ◽  
Serum Markers ◽  
Diagnostic Systems ◽  
Non Invasive ◽  
Type Iv ◽  
Acid Type ◽  
Experimental Laboratory ◽  
Invasive Techniques

Fibrosis and cirrhosis are traditionally diagnosed by making a biopsy. However, in recent decades, scientists around the world have shown that the accepted “gold standard of diagnosis” – morphological assessment of biopsy – has a number of limitations. The search for non-invasive techniques to diagnose fibrosis has led to the development of many scales using laboratory indices. Non-invasive diagnostic techniques are safer for the patient than liver biopsy. In addition, they can be repeated in a dynamic to assess the condition of the liver over time. Most currently available non-invasive diagnostic techniques are considerably cheaper than the accepted “gold standard”. Their practical use is increasing every year, and in a number of countries the frequency of liver biopsies in viral hepatitis B and C is steadily decreasing due to the development of serum and imaging diagnostic systems. Recent studies show that the assessment of the degree of fibrosis by non-invasive methods is as accurate as a morphological study. In recent years, a number of serum markers have been considered as non-invasive diagnostics of the stages of liver fibrosis, among which the largest number of studies are devoted to hyaluronic acid, type IV collagen, and their combination with various common laboratory tests. The latest non-invasive techniques will make a significant paradigm shift in the evaluation of liver fibrosis in the near future. In this review we have analyzed widely used as well as experimental laboratory techniques used in the diagnosis of liver fibrosis.

Characterization of Dislocations and Micropipes in 4H n+ SiC Substrates

2008 ◽  
Vol 600-603 ◽  
pp. 333-336 ◽  
Author(s):  
Ping Wu ◽  
Murugesu Yoganathan ◽  
Ilya Zwieback ◽  
Yi Chen ◽  
Michael Dudley
Keyword(s):  
Etch Pits ◽  
Screw Dislocations ◽  
X Ray ◽  
Nitrogen Doped ◽  
Different Types ◽  
History Of ◽  
Density Analysis ◽  
Threading Defects ◽  
Edge Dislocations

Etching of 4H-SiC wafers in molten KOH as a method for micropipe and dislocation density analysis was investigated. The obtained results were correlated with those of the synchrotron white beam x-ray topography. Heavily nitrogen-doped SiC shows a significantly different etching behavior in comparison with the low-doped material. This complicates identification of different types of threading defects. In particular, it is difficult to separate Threading Screw Dislocations (TSD) from Threading Edge Dislocations (TED). Depending on the level of doping and thermal history of the crystal, some of the etch pits emerging due to the 1c screw dislocations can be as large as those due to the micropipes.

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