scholarly journals A little key to oxalate formation in oil paints: protective patina or chemical reactor?

2018 ◽  
Vol 17 (3) ◽  
pp. 266-270 ◽  
Author(s):  
V. Otero ◽  
M. Vilarigues ◽  
L. Carlyle ◽  
M. Cotte ◽  
W. De Nolf ◽  
...  
Keyword(s):  
Synchrotron Radiation ◽  
Calcium Oxalate ◽  
Degradation Mechanism ◽  
Chemical Reactor ◽  
Chrome Yellow ◽  
Oil Paints

A novel degradation mechanism for 19th c. chrome yellow oil paints is proposed based on the oil photodegradation induced and calcium oxalate formation. It was proved by synchrotron radiation using artificially aged pigment reconstructions.

scholarly journals Structural elucidation of the degradation mechanism of nickel-rich layered cathodes during high-voltage cycling

2020 ◽  
Vol 56 (36) ◽  
pp. 4886-4889 ◽  
Author(s):  
Jing Lai ◽  
Jun Zhang ◽  
Zuowei Li ◽  
Yao Xiao ◽  
Weibo Hua ◽  
...  
Keyword(s):  
High Resolution ◽  
Synchrotron Radiation ◽  
High Voltage ◽  
Degradation Mechanism ◽  
Structural Elucidation ◽  
Synchrotron Radiation Diffraction ◽  
Voltage Region ◽  
High Voltage Region ◽  
Layered Cathodes

A splitting of two O3 phases, rather than the often observed O1 phases in the conventional LiCoO2 electrode, was discovered in the LiNi0.85Co0.10Mn0.05O2 at high-voltage region (>4.6 V) by in situ high-resolution synchrotron radiation diffraction.

Examination of the Photochemical Curing and Degradation of Oil Paints by Laser Raman Spectroscopy

1997 ◽  
Vol 51 (8) ◽  
pp. 1218-1223 ◽  
Author(s):  
Seiichiro Higuchi ◽  
Tosimitsu Hamada ◽  
Yohichi Gohshi
Keyword(s):  
Raman Spectroscopy ◽  
Degradation Mechanism ◽  
Paint Film ◽  
Laser Raman Spectroscopy ◽  
Polymerization Reaction ◽  
Laser Raman ◽  
Curing Reaction ◽  
Oil Paints ◽  
Paint Films ◽  
Reaction Schemes

In the present study, the curing and the degradation of oil paints by irradiation with ultraviolet light was investigated by laser Raman spectroscopy. At present, the curing reaction of oil paints is interpreted by several reaction schemes, although none of them is considered to be based on definite experimental evidence. The most typical examples are as follows: one is the radical termination reaction of the crosslinking type; the other, the polymerization reaction of the Diels—Alder reaction (diene reaction) type. In the present investigation, oil paint film (ZnO White and TiO2 White) was irradiated with a Xe lamp, and the time dependence of the Raman spectra of the films was examined. It is shown that the curing reaction cannot be explained by either of the above-mentioned reaction schemes. A new reaction mechanism for the curing and the degradation of paint films is proposed. It is concluded that the microscopic approach to the elucidation of the degradation mechanism of oil paint films based on Raman spectroscopy is very useful for the improvement of oil painting techniques.

Damages Induced by Synchrotron Radiation-Based X-ray Microanalysis in Chrome Yellow Paints and Related Cr-Compounds: Assessment, Quantification, and Mitigation Strategies

2020 ◽  
Vol 92 (20) ◽  
pp. 14164-14173
Author(s):  
Letizia Monico ◽  
Marine Cotte ◽  
Frederik Vanmeert ◽  
Lucia Amidani ◽  
Koen Janssens ◽  
...  
Keyword(s):  
Synchrotron Radiation ◽  
Mitigation Strategies ◽  
Chrome Yellow ◽  
X Ray

Correlating thermophysical properties with the molecular composition of 19th century chrome yellow oil paints

2017 ◽  
Vol 138 ◽  
pp. 201-211 ◽  
Author(s):  
Diogo Sanches ◽  
Ana Maria Ramos ◽  
Jorge F.J. Coelho ◽  
Cátia S.M.F. Costa ◽  
Márcia Vilarigues ◽  
...  
Keyword(s):  
19Th Century ◽  
Thermophysical Properties ◽  
Molecular Composition ◽  
Chrome Yellow ◽  
Oil Paints

scholarly journals Probing the chemistry of CdS paints in The Scream by in situ noninvasive spectroscopies and synchrotron radiation x-ray techniques

2020 ◽  
Vol 6 (20) ◽  
pp. eaay3514 ◽  
Author(s):  
Letizia Monico ◽  
Laura Cartechini ◽  
Francesca Rosi ◽  
Annalisa Chieli ◽  
Chiara Grazia ◽  
...  
Keyword(s):  
Synchrotron Radiation ◽  
Water Soluble ◽  
Key Factors ◽  
Internal Factors ◽  
Cadmium Sulfate ◽  
X Ray ◽  
Secondary Reactions ◽  
Spectroscopy Studies ◽  
Oil Paints

The degradation of cadmium sulfide (CdS)–based oil paints is a phenomenon potentially threatening the iconic painting The Scream (ca. 1910) by Edvard Munch (Munch Museum, Oslo) that is still poorly understood. Here, we provide evidence for the presence of cadmium sulfate and sulfites as alteration products of the original CdS-based paint and explore the external circumstances and internal factors causing this transformation. Macroscale in situ noninvasive spectroscopy studies of the painting in combination with synchrotron-radiation x-ray microspectroscopy investigations of a microsample and artificially aged mock-ups show that moisture and mobile chlorine compounds are key factors for promoting the oxidation of CdS, while light (photodegradation) plays a less important role. Furthermore, under exposure to humidity, parallel/secondary reactions involving dissolution, migration through the paint, and recrystallization of water-soluble phases of the paint are associated with the formation of cadmium sulfates.

Identification of calcium oxalate crystals in dried or fixed tobacco leaf

1984 ◽  
Vol 42 ◽  
pp. 288-289
Author(s):  
Vicki L. Baliga ◽  
Mary Ellen Counts
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Calcium Oxalate ◽  
Growth And Development ◽  
Polarized Light ◽  
Calcium Oxalate Crystals ◽  
X Ray Diffraction ◽  
X Ray ◽  
Transmission Electron ◽  
Scanning Electron

Calcium is an important element in the growth and development of plants and one form of calcium is calcium oxalate. Calcium oxalate has been found in leaf seed, stem material plant tissue culture, fungi and lichen using one or more of the following methods—polarized light microscopy (PLM), scanning electron microscopy (SEM), transmission electron microscopy (TEM) and x-ray diffraction.Two methods are presented here for qualitatively estimating calcium oxalate in dried or fixed tobacco (Nicotiana) leaf from different stalk positions using PLM. SEM, coupled with energy dispersive x-ray spectrometry (EDS), and powder x-ray diffraction were used to verify that the crystals observed in the dried leaf with PLM were calcium oxalate.

An SEM study of raphide crystal initials in the leaves of vitis (grape)

1995 ◽  
Vol 53 ◽  
pp. 984-985
Author(s):  
H. J. Arnott ◽  
M. A. Webb ◽  
L. E. Lopez
Keyword(s):  
Calcium Oxalate ◽  
Water Soluble ◽  
Calcium Oxalate Crystals ◽  
Calcium Oxalate Crystal ◽  
Oxalate Crystals ◽  
Large Numbers ◽  
Sem Study ◽  
The Matrix ◽  
Crystal Cells ◽  
Crystal Idioblast

Many papers have been published on the structure of calcium oxalate crystals in plants, however, few deal with the early development of crystals. Large numbers of idioblastic calcium oxalate crystal cells are found in the leaves of Vitis mustangensis, V. labrusca and V. vulpina. A crystal idioblast, or raphide cell, will produce 150-300 needle-like calcium oxalate crystals within a central vacuole. Each raphide crystal is autonomous, having been produced in a separate membrane-defined crystal chamber; the idioblast''s crystal complement is collectively embedded in a water soluble glycoprotein matrix which fills the vacuole. The crystals are twins, each having a pointed and a bidentate end (Fig 1); when mature they are about 0.5-1.2 μn in diameter and 30-70 μm in length. Crystal bundles, i.e., crystals and their matrix, can be isolated from leaves using 100% ETOH. If the bundles are treated with H2O the matrix surrounding the crystals rapidly disperses.

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