bluuebunny/crossref_metadata_2025_split huggingface dataset:
Waterlogged archaeological wood—chemical changes by conservation and degradation
Authors: Christensen M. , Frosch M. , Jensen P. , Schnell U. , Shashoua Y. , Nielsen O. F. 
Published: September 2006

AbstractConservation of waterlogged archaeological wooden artefacts from the Nydam Bog in the southern part of Denmark was investigated by Raman spectroscopy. Two different conservation methods were used: the cellosolve/petroleum method and the polyethylene glycol (PEG)/freeze‐drying method. Conservation with cellosolve/petroleum at both room and elevated temperatures was used to preserve archaeological arrows made from pinewood and ash wood. The double bonds in lignin were affected by the warm treatment. Holocellulose in the archaeological wooden arrows had decomposed completely. A band around 180 cm−1 in the R(v)‐representation of the low‐wavenumber Raman spectrum was used to monitor the presence of water in PEG2000 with a structure like the one in ‘free’ bulk water. The lignin/PEG2000 relative band intensities were used to make a quantitative estimate of the wood/PEG2000 ratio in a PEG2000 impregnated piece of hardwood. A decreasing degradation of holocellulose was observed from the surface to the centre of an oak piece from the Kolding Cog, built around 1200 A.D. A broad background was observed in the spectra recorded close to the surface of the plank. A similar, very intense, broad background was seen in untreated collapsed ash wood from the Nydam Bog. This broad background, most probably arising from fluorescence, was too intense to allow a Raman spectrum to be seen. In these cases, ATR‐FTIR spectroscopy is a valuable complementary tool in studies of waterlogged archaeological wood, confirming that holocellulose degrades more rapidly than lignin. Copyright © 2006 John Wiley & Sons, Ltd.
A study of medieval illuminated manuscripts by means of portable Raman equipments
Authors: Bersani Danilo , Lottici Pier Paolo , Vignali Francesca , Zanichelli Giuseppa 
Published: September 2006

AbstractThe pigments used in five important medieval illuminated manuscripts (Ms. Pal.6; Ms. Pal. 159; Ms. Pal. 212; Ms. Parm. 1650; Ms. Parm. 3063), all held in the Biblioteca Palatina in Parma (Italy), were analysed in situ by portable micro‐Raman instruments supplied by Renishaw and Horiba Jobin‐Yvon. In spite of a strong fluorescence background, different pigments were identified and important information on the pigment palette used in the manuscript illumination, helpful to clarify the history of the artworks, was obtained. Differences in the pigments used, suggesting late interventions, were found. In particular, an addition was identified in the Ms. Pal. 212 manuscript (Bruges—15th century), and late interventions were found in the coat of arms of Barbara of Brandenburg in her breviary (Ms. Pal. 6). A different origin for some rubrics and illumination was found in Ms. Parm. 3063, a 12th century Psalter, whereas common palettes for the different artists were confirmed for Ms. Parm. 1650 and for Ms. Pal. 159. Copyright © 2006 John Wiley & Sons, Ltd.
Micro‐Raman study of red decorations in French faiences of the 18th and 19th centuries
Authors: Marco de Lucas M. C. , Moncada F. , Rosen J. 
Published: September 2006

AbstractObtaining the red color was a technical and economic challenge for the French faience manufactories in the 18th and 19th centuries. The tendency of the red hematite to turn into drab brown during the firing process explains the difficulty in obtaining this color. Red decorations in shards coming from the four production centers of faience manufacturing during this period—Rouen (northwest), Nevers (central), Thiviers (southwest) and Argonne (northeast)—have been studied by means of micro‐Raman spectroscopy, scanning electron microscopy (SEM) and energy‐dispersive X‐ray spectroscopy (EDX). Among them, Thiviers appears to be the leader thanks to a particular reddish sandstone called ‘Grès de Thiviers’ (GT) available in the region. This material is composed of α‐quartz grains cemented by goethite (α‐FeOOH), leading to red hematite during the firing process. Raman spectra revealed that GT was also used by the Nevers manufactories in the middle of the 19th century instead of other methods used in the middle of the 18th century based on the mixture of Naples yellow with iron oxides. Manufactories in the north of France at Rouen and Argonne did not employ GT, but Naples yellow together with iron oxides or other pigments as ‘bol d'Arménie’. Copyright © 2006 John Wiley & Sons, Ltd.
Micro‐Raman study of aluminium‐bearing hematite from the slip of Gaul sigillata wares
Authors: Zoppi A. , Lofrumento C. , Castellucci E. M. , Dejoie C. , Sciau Ph. 
Published: September 2006

AbstractThe presence of sub‐microscopic Al‐Fe2O3 and Fe‐Al2O3 impure crystallites in the slip of sigillata wares from La Graufesenque (southern France) has recently been demonstrated by micro‐structural analyses, posing new questions about manufacturing processes and technological skills. To clarify the chemical composition and the spatial distribution of such phases within the slip, five representative sigillata wares were investigated by micro‐Raman spectroscopy. The recorded spectra show the typical hematite bands, though the Raman peaks are broadened and shifted, which agrees with a disordered phase. This is also reflected in a signal at 670 cm−1, while a shoulder close to 430 cm−1 is attributed to point defects, in agreement with the substitution of Fe atoms by Al atoms. A corundum spectrum was not detected indeed, probably hidden by the more intense hematite one. Spectral parameters were then estimated by a curve‐fitting analysis. Their comparison indicates a similarity among the investigated slips as well as uniformity within the slip layer. This suggests an awareness of the control of the production process among the local craftsmen. The spectral interpretation was assisted by reference spectra acquired on artificially doped hematite and corundum powder samples, which were used for probing the doping effect on the vibrational features of the pure crystallites. Copyright © 2006 John Wiley & Sons, Ltd.
Raman study of a ‘Tabula Colorum Physiologica’ in a 1686 printed journal
Authors: Baraldi Pietro , Fagnano Concezio , Bensi Paolo 
Published: September 2006

AbstractA Table painted in 1686 with spots of colors on paper was investigated. It appears that the Table is composed of pure pigments, and their mixtures in a 1:1 proportion. However, there were some problems when analyzing the pure compounds and the mixtures, due to the interaction of some pigments, as degradation had occurred. Possible explanations of the nature of the compound are analyzed and discussed. Copyright © 2006 John Wiley & Sons, Ltd.
Evidence for the degradation of an alloy pigment on an ancient Italian manuscript
Authors: Aceto Maurizio , Agostino Angelo , Boccaleri E. , Crivello F. , Garlanda A. Cerutti 
Published: September 2006

AbstractAn unusual metallic pigment was identified on an ancient Italian manuscript containing theHomilies on the Gospelsof Gregory the Great, belonging to the Archive and Chapter Library of Vercelli (Italy) and datable to the IX century. Green uncial text and part of decoration on this manuscript were described as ‘being of golden fashion’ in a book written at the beginning of XX century. Investigations carried out with portable XRF and Raman instruments revealed that the green colouration is actually the result of a marked degradation process that has altered the original composition of the pigment, an alloy of copper, lead and zinc. Probably because of the conditions of storage of the manuscript, the pigment tarnished owing a chemical process that could resemble the infamous ‘bronze disease’: that is, the conversion of metallic copper into inorganic salts. Measurements were performed bothin situ, i.e. directly on the manuscript, and on small fragments of ink collected from the page gutters. Copyright © 2006 John Wiley & Sons, Ltd.
Fuzzy logic: a technique to Raman spectra recognition
Authors: Castanys Tutzó M. , Perez‐Pueyo R. , Soneira M. J. , Ruiz Moreno S. 
Published: September 2006

AbstractThis paper presents two strategies based on fuzzy logic to identify unknown Raman spectra. Following the guidelines of visual inspection, it would be possible to compare the whole spectrum of the analyzed sample with the spectra of standard materials or, once the wavenumber positions of the bands of the unknown spectrum are localized, to compare them with those of the reference spectra. In both cases, it is necessary to have a database in which either the whole standard spectrum or the position of their bands are stored. In order to automate and to facilitate the task of comparison and identification of Raman spectra, two fuzzy logic systems are proposed. In one case, the designed fuzzy logic system uses a similarity index that quantifies the likeness between the compared spectra to find out to which material can the unknown spectrum correspond. In the other case, the proposed fuzzy logic system identifies the analyzed material, searching for the coincidence on the position of their bands with those of the considered standard materials. In both cases, the identification of artistic pigments can be achieved from their Raman spectra in a systematic and objective way. Copyright © 2006 John Wiley & Sons, Ltd.
Raman spectroscopic analysis of mediaeval wall paintings in the Palencia region, Spain
Authors: Villar S. E. Jorge , Edwards H. G. M. , Medina J. , Perez F. Rull 
Published: September 2006

AbstractThe use of Raman spectroscopic techniques for the analysis of wall paintings and frescoes has been reported previously. In this paper we present for the first time the Raman study of a collection of three wall paintings attributed to the same artist, dating from the XVth century, and a fourth wall painting dated three centuries earlier, all of them located in the same area, namely Palencia in northern Spain. From the results obtained here we can conclude that there is an identifiable recipe for the different colours and pigment tonalities, which had been maintained during the centuries regardless of the artistic origin of the work and did not seem to have been subjected to external influences. Also, the use of expensive pigments by the artist(s) is identified with the local importance of the figure, more than with the established religious hierarchy. Copyright © 2006 John Wiley & Sons, Ltd.
Raman spectroscopic analysis of a unique linen artefact: the HMS Victory Trafalgar sail
Authors: Edwards Howell G. M. , Nikhassan Nik F. , Farwell Dennis W. , Garside Paul , Wyeth Paul 
Published: September 2006

AbstractThe Battle of Trafalgar took place in 1805 and is generally accepted to mark the last occasion of combat between major fleets of sailing ships, when a combined Franco‐Spanish force of 33 battleships was defeated by a British fleet of 27 battleships blockading Cadiz and the approaches to the Mediterranean Sea. The HMS Victory Trafalgar sail, the fore‐topsail from Admiral Lord Nelson's flagship, was severely damaged and has since suffered significant natural deterioration. As the only extant early 19th century sail in the world, it is a unique artefact and arguably Britain's foremost maritime textile treasure. Prior to its display at the bicentennial exhibition in 2005, the sail was analysed by Raman spectroscopy. Complementary tensile tests were also completed on loose yarn from around the damaged areas. The mechanical data and Raman spectral comparisons suggest a good correspondence between the historic sailcloth and surrogate specimens. The latter were prepared by subjecting modern linen canvas to a four‐stage regime of artificial ageing in an attempt to reproduce the weakened state of the 200‐year‐old sailcloth, and provide model material to help appreciate the properties of the historic canvas. Detailed analysis suggests that certain Raman signatures are characteristic of ageing and may correlate with reduced performance of the fabric, suggesting that the technique could offer a non‐destructive approach to informing the preservation of a national textile heritage. Copyright © 2006 John Wiley & Sons, Ltd.
Preliminary investigations by Raman microscopy of prehistoric pigments in the wall‐painted cave at Roucadour, Quercy, France
Authors: Ospitali Francesca , Smith David C. , Lorblanchet Michel 
Published: September 2006

AbstractRaman microscopy (RM) was applied to an ongoing study of prehistoric pigments employed in Palaeolithic wall paintings in the Roucadour Cave (France). Micro‐samplings were carried out on parts of red or black painted figures representing animals and also negative human hands.These first analyses showed that in all the red micro‐samples, the main pigment is haematite. Where the tone was dark red, well‐formed crystals of haematite were identified, but magnetite, Mn oxide and carbon grains were also found. An intermediate mineral phase structurally in‐between goethite and haematite was also identified. In red samples, the yellowish hydrated species goethite was also detected. A great quantity of white, greyish‐white and yellowish‐white crystals were present in the pigment, and many of them were identified as calcite or quartz.The black pigments were constituted of well‐formed crystals of Mn oxyhydroxide in some black micro‐samples. Suggestions are made for the identification of some mineral species (bixbyite, hollandite, nsutite) but there is still much uncertainty on this topic. In others, amorphous carbon grains were utilised as the main pigment. This distinction is important for orienting the research towards a subsequent investigation by radiocarbon dating.Traces of anatase were found in black pigments, as were traces of rutile and gypsum in red pigments. It is interesting that haematite occurs in all the black pigments, black because of the great content of C or of Mn oxyhydroxide, and that several red pigments contain minor carbon, such that each pigment is a mixture with at least five different species in most micro‐samples. These data are compatible with the possibility that the prehistoric artists used naturally‐occurring impure geological materials (e.g. (Fe,Mn)‐ochre rocks) and natural biological materials (e.g. wood or oil to make charcoal or soot), but it cannot exclude the fact that they may have treated the raw materials and/or manufactured mixtures of purer materials. Copyright © 2006 John Wiley & Sons, Ltd.
Comparison of germanium oxide fibers with silica and sapphire fiber tips for transmission of erbium: YAG laser radiation
Authors: Polletto Travis J. , Ngo Anthony K. , Tchapyjnikov Alexei , Levin Ken , Tran Danh , Fried Nathaniel M. 
Published: September 2006

AbstractBackground and ObjectivesEndoscopic applications of the Erbium:YAG laser have been limited due to the lack of a suitable optical fiber delivery system. The purpose of this study was to compare the transmission of Er:YAG laser radiation through germanium oxide trunk fibers with silica and sapphire fiber tips for potential use in contact tissue ablation during endoscopy.Study Design/Materials and MethodsEr:YAG laser radiation with a wavelength of 2.94 µm, pulse length of 300 microseconds, pulse energies from 5 to 1,360 mJ, coupled into pulse repetition rates of 3–10 Hz, was through 1‐m‐long germanium oxide fibers with either 1‐cm‐long, 550‐µm‐diameter silica or sapphire tips.ResultsTransmission through the germanium oxide/sapphire fibers measured 65±5% compared with 55±4% for the germanium oxide/silica fibers (P<0.05). The damage threshold for the hybrid fibers averaged 309± 44 mJ and 126±43 mJ, respectively (n = 7 fibers each) (P<0.05). The highest pulse energies transmitted through the fibers were 700 mJ and 220 mJ, respectively.ConclusionsImproved index‐matching of the trunk fiber and fiber tip at 2.94 µm resulted in higher transmission and damage thresholds for the germanium oxide/sapphire fibers. The germanium oxide/sapphire fiber may represent a promising mid‐infrared optical fiber delivery system for use in endoscopic applications of the Er:YAG laser requiring a flexible, biocompatible, and robust fiber delivery system for contact tissue ablation. Lasers Surg. Med. 38:787–791, 2006. © 2006 Wiley‐Liss, Inc.
Fabrication and Characterization of an Organic‐Inorganic Gradient Surface made by Polymethylsilsesquioxane (PMSQ)
Authors: Liu Haiyun , Xu Jian , Li Yanfang , Li Baiyu , Ma Jun , Zhang Xiaoli 
Published: September 2006

AbstractSummary: A simple method for the fabrication of a chemical composition gradient from organic to inorganic by the pyrolysis of a polymethylsilsesquioxane (PMSQ) thin film in a gradient temperature field is reported. The resultant chemical gradient surface demonstrates gradual changes in wettability, and slight microstructural changes are observed along the substrate.FT‐IR spectra of gradient PMSQ surface along the length from the unheated side to the heated side.magnified imageFT‐IR spectra of gradient PMSQ surface along the length from the unheated side to the heated side.
Metal ion retention from aqueous solution using the ultrafiltration technique: preparation, retention capacity of copolymers of N‐maleimide derivatives with β‐methylhydrogen itaconate and metal complexes
Authors: Pizarro Guadalupe del C , Marambio Oscar G , Jeria‐Orell Manuel , Huerta Margarita R , Rodríguez Oscar O , Olea‐Azar Claudio , Rivas Bernabé L , Habicher Wolf D 
Published: September 2006

AbstractChlorophenylmaleimide (Cl‐PhMI) and N‐maleoylglycine (N‐MG) with β‐methylhydrogen itaconate (β‐MHI) were copolymerized by radical polymerization, and their metal ion retention capacity (MRC) and thermal behavior were studied. The copolymers were obtained by varying the mole fraction of Cl‐PhMI or N‐MG in the feed from 0.25 to 0.75. The monomer reactivity ratios, r1 and r2, were determined using the Kelen–Tüdös method. The molecular weight and polydispersity were also determined. The capacity to remove several metal ions, such as Cu(II), Cr(III), Co(II), Zn(II), Ni(II), Pb(II), and Fe(III), in aqueous phase was determined using the liquid‐phase polymer‐based retention technique. Inorganic ion interactions with the hydrophilic polymer were determined as a function of pH and the filtration factor. The MRC depends strongly on the pH. Metal ion retention increased with increases in pH and the content of β‐MHI units in the macromolecular backbone. The copolymers and polymer–metal complexes of transition metal ions were characterized using elemental analysis, Fourier transform infrared spectroscopy, 1H NMR, and electron paramagnetic resonance spectroscopy. The maximum MRC of Cu(II) ions of poly(Cl‐PhMI‐co‐β‐MHI) varied from 240 to 260 mg g−1, while the MRC of Cu(II) ions of poly(N‐MG‐co‐β‐MHI) varied from 270 to 318 mg g−1 at pH 5 and pH 7. The thermal behavior of the copolymers and polymer–metal complexes was studied using differential scanning calorimetry and thermogravimetry techniques under nitrogen atmosphere. The copolymers have a lower thermal decomposition temperature than the polymer‐metal complex for the same copolymer composition. The thermal behavior may be correlated with the copolymer composition. Copyright © 2006 Society of Chemical Industry
Autodiffusion: a novel method for emitter formation in crystalline silicon thin‐film solar cells
Authors: Wolf A. , Terheiden B. , Brendel R. 
Published: September 2006

AbstractThe in situ formation of an emitter in monocrystalline silicon thin‐film solar cells by solid‐state diffusion of dopants from the growth substrate during epitaxy is demonstrated. This approach, that we denote autodiffusion, combines the epitaxy and the diffusion into one single process. Layer‐transfer with porous silicon (PSI process) is used to fabricate n‐type silicon thin‐film solar cells. The cells feature a boron emitter on the cell rear side that is formed by autodiffusion. The sheet resistance of this autodiffused emitter is 330 Ω/□. An independently confirmed conversion efficiency of (14·5 ± 0·4)% with a high short circuit current density of (33·3 ± 0·8) mA/cm2is achieved for a 2 × 2 cm2large cell with a thickness of (24 ± 1) µm. Transferred n‐type silicon thin films made from the same run as the cells show effective carrier lifetimes exceeding 13 µs. From these samples a bulk diffusion lengthL > 111 µm is deduced. Amorphous silicon is used to passivate the rear surface of these samples after the layer‐transfer resulting in a surface recombination velocity lower than 38 cm/s. Copyright © 2006 John Wiley & Sons, Ltd.
Free radical polymerization with catalytic chain transfer: Using NMR to probe the strength of the cobalt–carbon bond in small molecule model reactions
Authors: Morrison David A. , Davis Thomas P. , Heuts Johan P. A. , Messerle Barbara , Gridnev Alexei A. 
Published: September 2006

AbstractThis work examines cobalt–carbon bond formation between the cobalt (II) macrocycle, (tetrakis(p‐methoxyphenyl)porphyrinato)cobalt (II), (TAP)Co, and a variety of radicals derived from vinyl compounds to facilitate a better understanding of the various factors affecting the cobalt–carbon bond strength in catalytic chain transfer polymerization. The reaction of (TAP)Co with the following vinylic molecules was studied: methacrylonitrile, cyclohexene, methyl methacrylate, styrene, methyl acrylate, vinyl acetate, vinyl benzoate, methyl crotonate, cis‐2‐pentenenitrile, and ethyl α‐hydroxymethacrylate. Different concentrations of each vinylic compound were added to (TAP)Co and 2,2′‐azobis(isobutyronitrile) in CDCl3 at 60 °C. The ratio of Co(III) to Co(II) and the nature of the radical bound to the cobalt macrocycle were determined via nuclear magnetic resonance measurements. Several factors are shown to affect the reaction of the radical and the cobalt (II) species (and hence the strength of the cobalt–carbon bond in the resulting compound). These factors are as follows: the number of pathways by which a radical may be derived from the vinyl compound; the variety of radicals that can be produced from the vinylic molecule; the stability of the radical(s) generated; and the relative propagation rate of the vinyl compound. A discussion on the relevance of this study to the behavior of different monomers in catalytic chain transfer reactions is included. © 2006 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 44: 6171–6189, 2006
Multi‐center nature of ethylene polymerization catalysts based on 2,6‐bis(imino)pyridyl complexes of iron and cobalt
Authors: Kissin Yury V. , Qian Changtao , Xie Guangyong , Chen Yaofeng 
Published: September 2006

Abstract2,6‐Bis(imino)pyridyl complexes of Fe and Co in combination with methylalumoxane form very active homogeneous catalytic systems for polymerization of ethylene. GPC analysis of the polymers prepared with the complexes indicates that the Co complexes produce single‐center catalysts whereas the Fe complexes produce catalysts with numerous types of active centers. Different centers in the latter catalyst systems respond differently to reaction conditions such as the reaction duration, the [MAO]:[Fe] ratio, the ethylene concentration, etc. The article examines the effects of reaction variables on the performance of both types of catalysts and proposes an explanation for the complex behavior of the catalysts derived from the Fe complexes. © 2006 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 44: 6159–6170, 2006