1,721,104 research outputs found
An approach to the identification of ambers from different archaeological sites (Part 2)
No full textChemical studies on resinous materials in archaeological remains are generally aimed at identifying the origin of the materials present, at studying the production and manufacturing techniques, and at improving techniques for their conservation and restoration.
This is particularly true for ambers remains. This paper presents some significant results for a systematic characterisation of the chemical composition of ambers of different provenance. The study has been carried out by using spectroscopic techniques, Raman and FT-IR with the aim ofcreating or extend FT-IR, Raman, FT-Raman libraries of geological and archaeological ambers. The data could be used as references in provenance studies of archaeological amber finds.
Based on this knowledge, archaeological resinous materials, recoveredin a various sites, dating back from the VI century BC to the second centuryAD, have been analysed and the relevant results discussed. Comparisons of analytical detailed results enable the recent and ancient history of the materials to be traced.
It is shown that provenance can be ascertained, in addition to the classical Beck’s method of FT-IR spectra (based on the special shape of the infrared spectrum in the 1500- 1000 cm-1 region), also by using Raman spectra and XRF data. The alteration of Museum preserved samples are taken into consideration for a description of the rapid changes of the spectra recorded
An approach to the identification of ambers from different archaeological sites (P1)
No full textChemical studies on resinous materials in archaeological remains are generally aimed at identifying the origin of the materials present, at studying the production and manufacturing techniques, and at improving techniques for their conservation and restoration.
This is particularly true for ambers remains. This paper presents some significant results for a systematic characterisation of the chemical composition of ambers of different provenance. The study has been carried out by using spectroscopic techniques, Raman and FT-IR with the aim of creating or extend FT-IR, Raman, FT-Raman libraries of geological and archaeological ambers. The data could be used as references in provenance studies of archaeological amber finds.
Based on this knowledge, archaeological resinous materials, recovered in a various sites, dating back from the ninth century BC to the second century AD, have been analysed and the relevant results discussed. Comparisons of analytical detailed results enable the recent and ancient history of the materials to be traced.
It is shown that provenance can be ascertained, in addition to the classical Beck’s method of FT-IR spectra (based on the special shape of the infrared spectrum in the 1500- 1000 cm-1 region), also by using Raman spectra and XRF data. The alteration of Museum preserved samples are taken into consideration for a description of the rapid changes of the spectra recorded
The identification of natural organic components in the construction materials of ancient earthen sites in China
No full textThis research begins with a review of the previous research on the application and identification of natural organic materials, such as starch and sugar, in ancient architectures in China. The review reveals that most (92.7%) of the existing methods relied upon “spot test”: a basic form of chemical reaction-based analysis. These tests are generally insufficient in sensitivity and specificity for the dependable identification of organic materials. Moreover, a significant gap is identified in the lack of blank tests for detecting organic residues in foundational materials like earth, which is crucial for establishing a baseline in such studies.
Through the analysis of modern and archaeological samples, the research develops and applies a novel analytical strategy for identifying starch and disaccharides. The new protocol includes pretreatment, sample screening, extraction of organics and identification at the molecular level, moving beyond the limitations of most existing analytical methods. The research explores the application of 8 analytical methods to develop this new protocol. Amongst them, FTIR and LOI are found suitable for the screening step. MALDI-TOF-MS and LC-MS/MS are effective in detecting starch and sucrose in earth samples at low detection limits. Significant findings from this new protocol include the identification of starch and sucrose in several archaeological samples, evidencing the artificial addition of these organics in earthen constructions. The outcomes not only enhance the methodology in archaeological science but also have important implications for the analysis and conservation of ancient sites
Developing the use of supercritical fluids in archaeological sciences
No full textInternational audienceWhile they have been used extensively in industry, supercritical fluids have not yet been fully explored in the field of archaeological sciences. There are only few documented applications which are mostly related to cleaning, drying, and conservation of delicate archaeological artefacts: actively eroding iron objects, silk textiles and paper from historical records have been cleaned and stabilised using supercritical CO2; supercritical fluids have also been used to dry waterlogged corks or other wooden materials; a further two publications have focused on the use of supercritical fluids prior to radiocarbon dating.Here, I will briefly review these applications and present the results of two recent pilot studies. We successfully optimised a procedure using supercritical fluids to extract lipids from a broad range of archaeological ceramic fragments without having to powder them [1]. We also successfully removed conservation materials and soil contaminants from archaeological bones prior to radiocarbon dating using supercritical fluids [2]. Results obtained on both sets of samples show that supercritical fluids can provide a more efficient and greener alternative to liquid solvents for the non-destructive extraction of organic materials from archaeological artefacts and contribute significantly to a range of research questions in archaeological sciences.[1] Devièse T, Van Ham-Meert A, Hare V, Lundy J, Hommel P, Ivanovich Bazaliiskii V and Orton J (2018). "Supercritical fluids for higher extraction yields of lipids from archaeological ceramics." Analytical Chemistry 90(4): 2420–2424.[2] Devièse T, Ribechini E, Querci D and Higham T (2019). "Assessing the efficiency of supercritical fluid extraction for the decontamination of archaeological bones prior to radiocarbon dating." Analyst 144: 6128-6135
Developing the use of supercritical fluids in archaeological sciences
No full textInternational audienceWhile they have been used extensively in industry, supercritical fluids have not yet been fully explored in the field of archaeological sciences. There are only few documented applications which are mostly related to cleaning, drying, and conservation of delicate archaeological artefacts: actively eroding iron objects, silk textiles and paper from historical records have been cleaned and stabilised using supercritical CO2; supercritical fluids have also been used to dry waterlogged corks or other wooden materials; a further two publications have focused on the use of supercritical fluids prior to radiocarbon dating.Here, I will briefly review these applications and present the results of two recent pilot studies. We successfully optimised a procedure using supercritical fluids to extract lipids from a broad range of archaeological ceramic fragments without having to powder them [1]. We also successfully removed conservation materials and soil contaminants from archaeological bones prior to radiocarbon dating using supercritical fluids [2]. Results obtained on both sets of samples show that supercritical fluids can provide a more efficient and greener alternative to liquid solvents for the non-destructive extraction of organic materials from archaeological artefacts and contribute significantly to a range of research questions in archaeological sciences.[1] Devièse T, Van Ham-Meert A, Hare V, Lundy J, Hommel P, Ivanovich Bazaliiskii V and Orton J (2018). "Supercritical fluids for higher extraction yields of lipids from archaeological ceramics." Analytical Chemistry 90(4): 2420–2424.[2] Devièse T, Ribechini E, Querci D and Higham T (2019). "Assessing the efficiency of supercritical fluid extraction for the decontamination of archaeological bones prior to radiocarbon dating." Analyst 144: 6128-6135
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Variations on the Author
Full text link“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Appropriate Similarity Measures for Author Cocitation Analysis
Full text linkWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
ELUCIDATING FUNERAL RITUALS IN BURIALS FROM THE END OF THE ROMAN EMPIRE: DEVELOPMENT OF A MULTI-ANALYTICAL APPROACH
No full textThis thesis presents the development and the principal results of a multi analytical approach dedicated to the characterisation of organic and inorganic materials recovered from three archaeological burials. The principal aim of this research was the identification of the preserved materials to understand their function in these funeral structures.
The archaeological materials studied come from the catacomb of Saints Peter and Marcellinus in Rome where numerous bodies were simultaneously pilled up together and from two French sites located in Anché and Naintré where the bodies were contained in lead coffins. All sites, originating in the Roman Empire, are dated to the second-third century AD.
The experimental part of the thesis was organised into three parts. First, the samples were observed and classified on the basis of their morphological features. Then, their analysis by FTIR spectroscopy allowed to obtain a first chemical identification. Finally, on the basis of the results obtained by FTIR spectroscopy, separative, structural and other spectroscopic techniques were implemented to enlarge knowledge relative to the nature and the state of degradation of each material. This multi-analytical protocol, optimised for the study of minute samples, allowed to identify a large range of materials such as resinous substances, dyes, minerals and textiles and provided new information, at a molecular level, about the processes of degradation of these materials in archaeological context.
The association of archaeological data with chemical information allowed to understand the function of most of the materials present into the tombs. It demonstrated the use of clay and precious imported resins to embalm the bodies. The presence of gypsum and calcite established that all bodies were packed, an unusual funeral practice at this time.
The same analytical protocol applied to anthropological materials, such as bones and skin fragments, shed new light on the diagenesis of human remains in their archaeological environment.
From an historical point of view, this research revealed new elements about the rich funeral practices of the Roman Empire and increases knowledge about the technical know-how of the period, such as textile manufacture and purple dyeing. Moreover, new information about the exchanges of precious materials such as Baltic amber, frankincense and oriental textiles at this time was obtained
- …
