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525 results on '"Howell G M Edwards"'

1. Porcelain shards from Portuguese wrecks: Raman spectroscopic analysis of marine archaeological ceramics

Author

Elizabeth A. Carter, Michelle L. Wood, Danita de Waal, and Howell G. M. Edwards

Subjects
Raman spectroscopy, β-wollastonite, Anatase, Porcelain, Ming period, Fine Arts, Analytical chemistry, QD71-142
Abstract

Abstract Raman spectroscopic analysis of shards recovered from two Portuguese shipwrecks, the Santo Espirito (1608) and the Santa Maria Madre de Deus (1643), believed to be carrying porcelains of the Ming period have revealed some interesting and novel results that inform historical ideas of porcelain production. The porcelain body of two of the four shards from the Santa Maria Madre de Deus were found to contain anatase, a low temperature polymorph of titanium dioxide, and β-wollastonite a mineral characteristic of soft-paste porcelains that are made at medium-temperature firing conditions. Previously, β-wollastonite has been found in a range of sixteenth to nineteenth century European porcelains but this is the first report of its detection in porcelain believed to be from the Ming period. These same shards exhibited unusual spectral features that were attributed to the resonance enhancement of rare earth elements that resulted from excitation using a near-infrared source.

Published
2017
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3. Raman identification of the different glazing technologies of Blue-and-White Ming porcelains

Author

Anh-Tu Ngo, Linda C. Prinsloo, Philippe Colomban, Howell G. M. Edwards, L. Valérie Esterhuizen, De la Molécule aux Nanos-objets : Réactivité, Interactions et Spectroscopies (MONARIS), Institut de Chimie du CNRS (INC)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), University of Bradford, and University of the Witwatersrand [Johannesburg] (WITS)

Subjects
Anatase, Materials science, Mullite, 02 engineering and technology, engineering.material, 01 natural sciences, Wollastonite, Raman microspectroscopy, symbols.namesake, chemistry.chemical_compound, Materials Chemistry, [CHIM]Chemical Sciences, Quartz, Process Chemistry and Technology, 010401 analytical chemistry, Glaze, Metallurgy, Cobalt, 021001 nanoscience & nanotechnology, Silicate, 0104 chemical sciences, Surfaces, Coatings and Films, Electronic, Optical and Magnetic Materials, Blue, chemistry, Porcelain, Ceramics and Composites, engineering, symbols, 0210 nano-technology, Raman spectroscopy, Composition, Black spot
Abstract

International audience; Shards of Blue-and-White Ming porcelain from shipwrecks of Portuguese ships found on the coasts of South Africa plus a shard from Mombasa (Kenya) were analyzed by optical microscopy, SEM-EDS and Raman microspectroscopy (458 nm). Whereas the Raman signature of porcelain body paste compositions which are based on mullite, quartz and an amorphous phase with the minor presence of anatase and feldspar are very comparable whatever the variable alumina content, at least two types of glazes are observed: a high-temperature soda-potassium glaze, and glazes richer in calcium and similar to a celadon glaze (with the possibility of wollastonite formation). The blue decoration is obtained with a material rich in manganese typical of the Ming productions. Some shards exhibit a two-layer glaze and the blue decoration is either placed under-glaze, or in-glaze as found in the Vietnamese productions of the same period. Previous assignments of the Raman signature of feldspar to cobalt aluminate are now not favoured (blue colour is obtained with Co2+ ions dissolved in the glassy silicate) and several black spots exhibit the characteristic spectrum of an epsilon Fe2O3 phase being present.

Published
2022
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13. Raman analysis of a shocked planetary surface analogue: Implications for habitability on Mars

Author

Melissa McHugh, Jose Antonio Manrique, Guillermo Lopez-Reyes, Mike J. Cole, Fernando Rull, Marco Veneranda, Ian Hutchinson, Carlos Pérez, Howell G. M. Edwards, Aurelio Sanz Arranz, Mark J. Burchell, Hannah Natasha Lerman, John Parnell, and Andoni Moral

Subjects
symbols.namesake, Planetary surface, chemistry, Habitability, symbols, chemistry.chemical_element, General Materials Science, Mars Exploration Program, Raman spectroscopy, Carbon, Spectroscopy, Geology, Astrobiology
Published
2021
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14. Tribute to Derek Long: An instant snapshot of the development of Raman spectroscopy and its application in the fields of instrumentation and methodology, solid‐state materials, cultural heritage, DFT modeling and applications in biology, microbiology, and medicine

Author

Howell G. M. Edwards, Philippe Colomban, Wolfgang Kiefer, and Laurence A. Nafie

Subjects
Snapshot (photography), Cultural heritage, Engineering, business.industry, Solid-state, Systems engineering, General Materials Science, Instrumentation (computer programming), business, Spectroscopy, Instant
Published
2021
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15. Non‐invasive and non‐destructive Raman spectroscopic characterization of some Brazilian ethnographic resins

Author

Dalva Lúcia Araújo de Faria, Silvia Cunha Lima, Howell G. M. Edwards, Marta S. Maier, Sara D. Parera, and Marisa Coutinho Afonso

Subjects
symbols.namesake, Chemistry, Non destructive, Non invasive, symbols, General Materials Science, ACERVO MUSEOLÓGICO, Raman spectroscopy, Spectroscopy, Nuclear chemistry, Characterization (materials science)
Published
2021
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41. A spectroscopic analysis of late 16th century domestic wall paintings in the Saracens Head Inn, Nottinghamshire, UK

Author

Luiz Fernando C. de Oliveira, Richard Telford, Christopher Brooke, Howell G. M. Edwards, and Alex Surtees

Subjects
Painting, media_common.quotation_subject, Raman imaging, government.political_district, Art, Ancient history, symbols.namesake, government, symbols, Head (vessel), General Materials Science, Nottinghamshire, Raman spectroscopy, Spectroscopy, media_common
Published
2021
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42. The use of Raman and infrared spectroscopy in determining the space symmetry group among the groups with the same rules of systematic absence in the diffraction patterns: Some basic principles and applications

Author

T. N. Moroz and Howell G. M. Edwards

Subjects
Diffraction, symbols.namesake, Materials science, Infrared, symbols, Infrared spectroscopy, General Materials Science, Symmetry group, Space (mathematics), Raman spectroscopy, Molecular physics, Spectroscopy
Published
2021
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44. Raman spectroscopic search for scytonemin and gloeocapsin in endolithic colonizations in large gypsum crystals

Author

Howell G. M. Edwards, Jan Jehlička, Jan Mareš, Ivan Němec, Kateřina Němečková, and Adam Culka

Subjects
Gypsum, Materials science, Scytonemin, engineering.material, Photochemistry, symbols.namesake, chemistry.chemical_compound, chemistry, engineering, symbols, General Materials Science, Raman spectroscopy, Gloeocapsin, Spectroscopy
Published
2021
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47. Green and blue pigments in Roman wall paintings: A challenge for Raman spectroscopy

Author

Susana E. Jorge-Villar and Howell G. M. Edwards

Subjects
Azurite, media_common.quotation_subject, Mineralogy, Malachite, Art, engineering.material, Indigo, Chrysocolla, Egyptian blue, chemistry.chemical_compound, chemistry, visual_art, visual_art.visual_art_medium, engineering, Celadonite, General Materials Science, Spectroscopy, Lazurite, Verdigris, media_common
Abstract

In Roman wall paintings, blue and green colours are less commonly encountered than red and yellow and were more expensive. Despite this, Pliny and Vitruvius describe the more common compounds used for these pigments, translated today as azurite, lazurite, chrysocolla, indigo and Egyptian blue for blues and verdigris, malachite, celadonite, glauconite and chlorite for greens. A confusion in their nomenclature is often found in the most common blue pigment that is the first manufactured compound, Egyptian blue. For greens, celadonite and glauconite were usual and called generically ‘green earths’, but they prove to be difficult to characterize analytically. In this paper, we evaluate the Raman spectroscopic identification of the characteristic Roman blue and green pigments as used in wall paintings using two different laser wavelengths (green and near infrared) and clarify their nomenclature.

Published
2021
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49. Raman spectroscopic and SEM/EDXS analyses of high translucent Nantgarw porcelain

Author

Howell G. M. Edwards, Philippe Colomban, Charles Fountain, De la Molécule aux Nanos-objets : Réactivité, Interactions et Spectroscopies (MONARIS), and Institut de Chimie du CNRS (INC)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)

Subjects
010302 applied physics, Materials science, Glaze, Metallurgy, 02 engineering and technology, 021001 nanoscience & nanotechnology, Bone china, 01 natural sciences, symbols.namesake, 0103 physical sciences, Materials Chemistry, Ceramics and Composites, symbols, [CHIM]Chemical Sciences, 0210 nano-technology, Spectral data, Raman spectroscopy
Abstract

In the first quarter of the 19th Century the factory established at Nantgarw created some of the finest quality porcelain in the world, rivalling that of Sevres, but beset by economic difficulties resulting from extraordinarily high kiln losses approaching 90 %, the production which started in 1817 (ceased by 1820) produced the finest translucency ever achieved in Georgian porcelains. An opportunity has arisen to analyse rare Nantgarw porcelain shards excavated archaeologically from the Nantgarw China Works site. Two types of compositions, bone china and silica-rich pastes are identified by Raman and SEM-EDXS analyse, confirming some ancient studies. The spectral data from “sagged” silica-rich shards are interpreted to reveal potential explanations of the manufacturing fault which significantly contributed to the demise of the ceramics factory. Finally, the pigments and glaze used in Nantgarw porcelain decoration have been analysed and identified for the first time.

Published
2020
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50. Involvement of Streptomyces in the Deterioration of Cultural Heritage Materials Through Biomineralization and Bio-Pigment Production Pathways: A Review

Author

Mohamed F. Ghaly, Mahmoud E.F. Abdel-Haliem, Mona F. Ali, Akmal A. Sakr, and Howell G. M. Edwards

Subjects
0301 basic medicine, biology, 030106 microbiology, macromolecular substances, 010501 environmental sciences, biology.organism_classification, 01 natural sciences, Microbiology, Streptomyces, Cultural heritage, Melanin, 03 medical and health sciences, Pigment, visual_art, Botany, Earth and Planetary Sciences (miscellaneous), visual_art.visual_art_medium, Environmental Chemistry, 0105 earth and related environmental sciences, General Environmental Science, Biomineralization
Abstract

Streptomyces are involved in the deterioration of cultural heritage materials through several pathways, the most important of these are biomineralization and bio-pigment production. The biominerali...

Published
2020
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