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On the use of photobleaching to reduce fluorescence background in Raman spectroscopy to improve the reliability of pigment identification on painted textiles
No full textSubjecting a specimen of red lead watercolour paint on silk to photobleaching was demonstrated to be a simple means by which to engineer a reduction in the magnitude of the fluorescent background that was approximately exponential with time, with a corresponding improvement in the signal to noise ratio of the Raman spectrum, thus rendering the characteristic peaks more easily visible and allowing more confident identification of the pigment. However, relative heights of the Raman peaks obtained from the sample were seen to alter progressively as a result of irradiation, indicating that some component of the sample was undergoing degradation that may result in longer-term damage to a fragile historic artefact. It was also shown that crystals of the lead monoxide pigment massicot were present in the samples ofred lead on a painted silk artefact dating from 1750. It is concluded that this was either due to deliberate mixing of pigments by the artist, contrary to historic records, or as a result of the roasting techniques used to create red lead pigments at the time and not due to thermal degradation of the pigment during Raman analysis
Surveying silk fibre degradation by crystallinity determination: a study on the Tang-Dynasty silk treasure from Famen Temple, China
No full textWhen Chinese archaeologists opened an unknown vault under the collapsed pagoda of Famen Temple near Xian (Shaanxi Province, NW China) in 1987, they found a vast amount of valuable silk textiles. The degraded textiles were part of a treasure comprising hundreds of artifacts deposited by Tang dynasty (ad 618–907) emperors as a gift to the temple. Run as a bilateral German-Chinese project, the Roemisch-Germanisches Zentralmuseum Mainz established a textile conservation laboratory in Shaanxi´s provincial capital Xian in 2001, joining numerous other laboratories that have existed there since the early 1990s.This preliminary study represents part of an ongoing investigation programme that accompanies the conservation work. The Tang dynasty silk is generally in a very poor state of preservation as a result of its long burial period. Large sections have only survived as an amorphous brown mass of fibre debris. Some parts are better preserved, however, offering the unique opportunity to study the whole range of degradation stages on ancient silks.This preliminary scientific investigation focuses on the determination of the silk fibres’ crystallinity and its relation to the ageing process. As we know from modern material, silk is mainly crystalline, albeit in a somewhat amorphous state. The methods of investigation used were X-ray diffraction (XRD) using synchrotron radiation, which is a new way to determine crystallinity of ancient silk fibres; and polarized Fourier transform infrared spectroscopy (FTIR) for the determination of crystallite orientation. Both methods were specifically devised to gain information on small single fibres
Raman microspectroscopy interrogating 19th and 20th century painted trades union banners
No full textWe have previously developed protocols for the application of Raman microspectroscopy to studies on painted textiles. We have further assessed the value of such microanalyses in the identification of both inorganic and organic constituents, including original components and consolidants used in conservation treatments. This paper presents the results of a recent study on a number of 19th- and 20th-century trades union banners directed at collating a spectral database of inorganic pigments used in the illustrations and at probing the preparative process prior to painting. Such information will contribute to an understanding of the manufacture of such banners and their current condition, leading to the development of optimum conservation procedures.While Raman spectroscopy has the potential to be used in situ and, with the appropriate protocol, is non-destructive, nonetheless we have found that the analysis of resin-embedded cross-sections is to be preferred with microtoming providing the cleanest sample surface. The optimum methodology for acquiring good quality Raman spectra is described including operation in the confocal mode, with consideration of fluorescence, interference from resin, laser-induced photochemistry, and so on
Photograph of N.C. Wyeth Painting of Lincoln and Johnson
No full textThe color photographic print depicts and image of N.C. Wyeth\u27s painting of Abraham Lincoln and Andrew Johnson.https://scholarsjunction.msstate.edu/fvw-photographs/1531/thumbnail.jp
Wyeth Laboratories Check
No full textA check was presented in the amount of $5,000 to Dr. Howard H. Bradshaw from Wyeth Laboratories in 1960, designated for surgical research. In photo from (L-R) Charles Suttle from Wyeth Laboratories; Dr. Bradshaw, who in 1960 was professor and chairman of the Department of Surgery; and Dr. Coy C. Carpenter, dean of Bowman Gray School of Medicine
Part of the property of the Wyeth City Land and Improvement Company : Marshall County, Ala. in Township 8, Range 3
No full textProposed development was to be named in honor of John Allan Wyeth, Confederate veteran and nationally-known physician.; Contains certifications by Judge of Probate, etc.; Reduced photocopy of original
Polarised ATR-FTIR characterisation of cellulosic fibres in relation to historic artefacts
No full textThe utility of polarised attenuated-total-reflectance (ATR) FTIR spectroscopy was investigated for the identification of cellulosic fibres and characterisation of their state of degradation.Turning the polariser so that the electric vector is parallel (Epll) or perpendicular (Eprp) provides a means of assessing the orientational crystallinity of cellulose from the polarised spectra of aligned plant fibres. Analysis of the spectra can reveal both the angle of microfibrillar wind and its directionality. Here, the best fits to the data suggest: flax 7?/S-spiral; sisal 25?/Z-spiral; coir 70?/S-spiral, where the predominant twist is given for the outer cell-wall regions sampled. Polarised-ATR-FTIR also allows degradation of the amorphous component of cellulose to be highlighted, by recording spectra with the optimum alignment of fibre and polariser. Changes observed on thermal ageing of flax in air at 190 ?C are consistent with oxidation of amorphous cellulose and formation of carbonyl and carboxylate moieties; the non-dichroic nature of the carbonyl band confirms that the ordered crystalline regions were not primarily involved
iRat: Intelligent rat animat technology
No full textThis paper presents the iRat (intelligent Rat animat technology), a robot designed for robotic and neuroscience teams as a tool for studies in navigation, embodied cognition, and neuroscience research. The rat animat has capabilities comparable to the popular standard Pioneer DX robots but is an order of magnitude smaller in size and weight. The robot's volume is approximately 0.08m with a mass of 0.5kg and has visual, proximity, and odometry sensors, a differential drive, a 1 GHz x86 computer, and LCD navigation pad interface. To facilitate the value of the platform to a broader range of researchers, the robot uses the Player-Stage framework, and C/C++, Python, and MATLAB APIs have been tested in real time. Two studies of neural simulation for robot navigation have confirmed the rat animat's capabilities
Pineapple Patch at Wyeth Place
No full textThe pineapple patch on the Wyeth Estate located north of Welborne, from Interlachen to Center Street. J.H. Wyeth was a Rollins trustee from 1901 to 1906
Art review of N.C. Wyeth: Precious Time, an exhibition of works by N. C. Wyet
No full textArt review of N.C. Wyeth: Precious Time, an exhibition of works by N. C. Wyeth, which is being presented at the Portland Museum of Art in Portland through October 15
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