Preliminary study of a Georgia O'Keeffe pastel drawing using XRF and μXRD

2009 ◽  
Vol 24 (2) ◽  
pp. 116-123 ◽  
Author(s):  
Lynn B. Brostoff ◽  
Catherine I. Maynor ◽  
Robert J. Speakman

X-ray fluorescence spectrometry (XRF) and micro-X-ray diffraction (μXRD) were used to analyze the composition of pigments on a pastel drawing, Special No. 32, by Georgia O’Keeffe. XRF analyses showed that, among other pigments present in the drawing, the red, orange, and yellow pigments may possibly be identified with lead- and chromium-based pigments: lead chromates, red and yellow lead oxides, and/or lead carbonates, plus calcium-based pastel fillers, such as whiting or gypsum. XRD examination of a sample removed from a dark mottled area of coral red pastel confirmed that this pigment layer, which is associated with a darkened appearance and high Pb:Cr ratios, matches the red lead oxide, minium (2PbO⋅PbO2).

Coatings ◽  
2021 ◽  
Vol 11 (1) ◽  
pp. 37
Author(s):  
Yan Liu ◽  
Taoling Dong ◽  
Kun Zhang ◽  
Fuwei Yang ◽  
Liqin Wang

Targeting cleaning of the artificial gypsum layer on white marble was studied. It was conducted by means of the specific depletion of the calcium and sulfate ions by the barium carbonate scavenger, which led to the continuous dissolution and clearance of gypsum layer. The cleaning effect was evaluated by scanning electron microscopy with energy dispersive X-ray spectroscopy (SEM/EDX), X-ray diffraction (XRD), capillary suction, and color difference measurement. By this method, only the gypsum layer was cleared away and the carbonate substrate of marble was left intact at the same time. This method will be highly useful for the conservation of marble relics from surface weathering.


2019 ◽  
Vol 964 ◽  
pp. 240-245 ◽  
Author(s):  
Amaliya Rasyida ◽  
Thalyta Rizkha Pradipta ◽  
Sigit Tri Wicaksono ◽  
Vania Mitha Pratiwi ◽  
Yeny Widya Rakhmawati

Utilization of brown algae especially in Madura, where it’s close to Surabaya, only limited for food. This become a reference for developing and increasing the potential of this algae by extracting one of the ingredients, namely alginate. This paper deals with the characterization of sodium alginate extracted from sargassum sp. using modified-purified calcium routes. The extracted sodium alginate will be further used as composite hydrogel materials and compared with commercial sodium alginate. Hereafter, the synthesized composite is expected to be bio-ink for 3d printer. Chemical composition analysis were analyzed using X-Ray Fluorosense (XRF) followed by Fourier-transform infrared spectroscopy (FTIR) analysis to identify the functional group of composite and X-Ray Diffraction (XRD). Furthermore, viscosity bath is performed to compare the viscosity of extracted and commercial one. The result shows that modified-purified calcium routes in the extraction process of sodium alginate is desirable for improving their properties. Interestingly enough, with the goal of using it as bio-ink in 3d printed fabrication, the synthesized composite shows viscosity, 300 cSt, which meets the criteria for bio-ink in 3d printer.


2010 ◽  
Vol 12 (4) ◽  
pp. 53-57 ◽  
Author(s):  
Agata Markowska-Szczupak ◽  
Krzysztof Ulfig ◽  
Barbara Grzmil ◽  
Antoni Morawski

A preliminary study on antifungal effect of TiO2-based paints in natural indoor light The antifungal activity of four commercial photocatalytic paints (KEIM Ecosil ME, Titanium FA, Photo Silicate and Silicate D) in natural indoor light was investigated. The paints contained TiO2 in rutile and anatase crystalline forms as evidenced by means of the X-ray diffraction analysis. In most cases the paints inhibited growth of fungi viz. Trichoderma viride, Aspergillus niger, Coonemeria crustacea, Eurotium herbariorum, and Dactylomyces sp. The KEIM Ecosil ME paint displayed the highest antifungal effect in the light, which could be explained with the highest anatase content. The paint antifungal activity and the fungal sensitivity to the TiO2-mediated photocatalytic reaction both decreased in the following orders: KEIM Ecosil ME > Titanium FA > Photo Silicate > Silicate D and T. viride > Dactylomyces sp. > A. niger > E. herbariorum.


EKSPLORIUM ◽  
2020 ◽  
Vol 41 (2) ◽  
pp. 73
Author(s):  
Windi Anarta Draniswari ◽  
Sekar Indah Tri Kusuma ◽  
Tyto Baskara Adimedha ◽  
I Gde Sukadana

ABSTRAK Anomali radiometri telah ditemukan di area Sungai Amplas pada bongkah batuan vulkanik. Nilai yang terukur dari spektrometer gama adalah 787 ppm eU dan 223 ppm eTh. Penemuan ini menarik untuk pengembangan eksplorasi. Studi lebih lanjut diperlukan untuk mengetahui karekteristik batuan pembawa mineral radioaktif dari sampel in-situ. Penelitian ini bertujuan untuk mengetahui karakteristik petrologi dan geokimia batuan vulkanik Ampalas sebagai studi awal untuk mengetahui proses akumulasi mineral radioaktif pada batuan vulkanik Ampalas. Metodologi yang digunakan meliputi pengamatan lapangan, pengambilan sampel batuan, analisis petrografi dan X-Ray Fluorescence (XRF). Batuan vulkanik ampalas tersusun atas ponolit, foidit, dan foid-syenit. Tekstur batuannya terdiri dari porfiritik, aliran, rim piroksen, zoning, pseudo-leusit, korosi, inklusi mafik, dan sieve. Karakteristik geokimia menunjukkan alkalinitas tinggi dan indikasi pengayaan mineral radioaktif yang tersebar dalam batuan. Proses magmatis yang berperan dalam pembentukan batuan vulkanik adalah fraksionasi kristal (fraksionasi leusit dan alkali felspar), asimilasi kerak kontinen, dan pencampuran magma. Interaksi antara magma dan kerak menyebabkan diferensiasi magma berkelanjutan yang menghasilkan akumulasi uranium dan torium lebih tinggi.ABSTRACT Anomalous radiometry has been found in Ampalas River Area on volcanic rock boulder. The values measured from gamma spectrometer are 787 ppm eU and 223 ppm eTh. This discovery is promising for exploration development. Further study need to figure the radioactive mineral bearing rock characteristic from in-situ samples. The research aim is to determine the petrology and geochemical characteristics of Ampalas volcanic rocks as preliminary study to find radioactive mineral accumulation process of Ampalas volcanic rocks. The methodologies are field observation, rock sampling, petrography, and X-Ray fluorescence (XRF) analyses. The Ampalas volcanic rocks consist of phonolite, phoidite, and phoid syenite. Their textures are porphyritic, flow, pyroxene rim, zoning, pseudo-leucite, corrosion, mafic inclusions, and sieve. The geochemical characteristics show high alkalinity and radioactive mineral enrichment disseminating on rock. The magmatic processes which play a significant role in radioactive mineral-bearing rocks formation are crystal fractionations (leucite and alkaline feldspar fractionations), continental crust assimilation, and magma mixing. Long interaction between magma and crust creates advanced magma differentiation causing higher uranium and thorium accumulation.  


Geosciences ◽  
2019 ◽  
Vol 9 (4) ◽  
pp. 172 ◽  
Author(s):  
Michela Ricca ◽  
Giuseppe Paladini ◽  
Natalia Rovella ◽  
Silvestro Antonio Ruffolo ◽  
Luciana Randazzo ◽  
...  

This work focused on the study of decorated pottery dated back to the 16th century from the Roman archaeological site of Villa dei Quintili, a monumental complex located in the south-eastern part of Rome (Italy). A minero-petrographic and geochemical study was undertaken to analyse five archaeological samples in order to define textural features and raw materials used for their production, along with the chemical and physical composition of the superficial decorative glazed coatings. For this purpose, different analytical methods were used, such as polarising optical microscope (POM), X-ray diffraction (XRD), micro-Raman spectroscopy, X-Ray fluorescence (XRF), and electron microprobe analysis coupled with energy dispersive spectrometry (EMPA-EDS). The results of such a multidisciplinary approach allowed us to achieve important results crucial to recognise the shards as majolica of the Renaissance period, improving knowledge about manufacturing processes of these renowned painted ceramic artefacts.


1993 ◽  
Vol 310 ◽  
Author(s):  
Lynnette D. Madsen ◽  
Louise Weaver

AbstractSingle oxides (with titanium or lead) deposited as thin films by low pressure metalorganic chemical vapour deposition were investigated by x-ray diffraction and Raman spectroscopy. Examination of mixed oxides (titanates) and silicates were also carried out using these techniques. The crystallographic nature of these thin films were examined and comparisons made to their bulk counterparts. The deposition and anneal conditions 600 for producing cubic PbTiO3 films are discussed briefly.


2020 ◽  
Vol 9 (6) ◽  
pp. 456-467
Author(s):  
Yassine Salhi ◽  
Sghir Cherrouf ◽  
Mohammed Cherkaoui

The electrodeposition of Cu-Zn-Sn (CZT) coating at ambient temperature was investigated. The bath consists of metal salts SnSO4, ZnSO4,7H2O and CuSO4,5H2O and sodium citrate (NaC6H5Na3O7,2H2O) as a complexing agent. For precipitation, the pH is maintained at 5. The reducing of copper, tin and zinc through Cu2HCit3−, Sncit2− and ZnHcit− complexes respectively are confirmed by the presence of three cathodic peaks on the voltammograms realized on steel and ITO glass substrate. X-ray diffraction patterns revealed peaks corresponding to the phases: Cu-Zn cubic, Cu-Sn hexagonal and β-Sn tetragonal. The deposition rate is 35 μm/h. SEM observation and EDAX analysis showed that the coating consists of a uniform CZT layer of which composition is 55% copper, 20% zinc and 25% tin at -1.5V.  A preliminary study showed a remarkable improvement in the corrosion resistance of CZT coated steel in comparison with bare steel.


2017 ◽  
Vol 19 (4) ◽  
pp. 217-222
Author(s):  
Wan Jeffrey Basirun ◽  
Idris Mohamed Saeed ◽  
Hanieh Ghadimi ◽  
Magaji Ladan ◽  
Mohammad Reza Mahmoudian ◽  
...  

The corrosion of lead in methanesulfonic acid solution in the presence of a MnO2 air cathode in a primary lead-air cell is in-vestigated. The highest power density of the lead-air cell is 2.8 mW cm-2. X-ray photoelectron spectroscopy and powder X-ray diffraction results demonstrate the formation of lead (II) oxide and lead (IV) dioxide on the air cathode after continuous discharge. Field emission scanning electron microscopy image shows that the surface coverage of lead (II) oxide and lead (IV) dioxide on the air cathode is only partial and will allow oxygen reduction.


1990 ◽  
Vol 185 ◽  
Author(s):  
L. P. Stodulski ◽  
V. J. Dorge

AbstractDuring conservation, The Detroit Institute of Arts' late Gothic carved wooden sculpture, Madonna and Child, was found to have extensive, though fragmentary, remains of the original polychromy and at least four subsequent “restoration” overpaints. The materials present in the original and overpaintings were probed by polarizing microscopic and X-ray diffraction analyses of individual paint specimens, and scanning electron microscopic/energydispersive X-ray analyses of cross sections prepared using an ultramicrotome. Several sections were also studied using ultraviolet fluorescence microscopic staining techniques to determine the nature of the media used.The pigments identified include azurite, lead white, calcite, vermilion, red lead, hematite, red lakes and glazes, smalt and Prussian blue. Gold and silver metal leafs were also detected. The deteriorated remains of the late Gothic pressed brocade technique, and the use of “bronze” paint to approximate genuine gold leaf on a later addition to the sculpture, are also discussed.


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