Reconstructing change in firing technology during the Final Neolithic–Early Bronze Age transition in Phaistos, Crete. Just the tip of the iceberg?

Changes in firing practice have been suggested as representing a revolution in ceramic technology at the beginning of the Bronze Age in Crete. The introduction of kiln structures has been held responsible for such a change, perhaps by newcomers to the island, along with other innovative technologies. However, these hypotheses were often based on limited analytical data and mostly on macroscopic examination. This paper re-examines the suggestion of a transformation in firing technology at the beginning of the Bronze Age by presenting analyses of the rich ceramic assemblage from the site of Phaistos in South-Central Crete, which offers a rare, good stratigraphic sequence from the end of the Final Neolithic into the Early Bronze Age. Here, firing technology is reconstructed by macroscopic examination of colour across vessel breaks, by SEM examination and FT-IR analysis. This allows the reconstruction of temperature ranges and firing rates over the phases considered and a re-assessment of changes in firing technology, revealing a more multi-faceted pattern of change. Finally, changes in firing procedure are contextualised in the overall ceramic operational sequence, revealing a complex, stepped picture of change in ceramic production over the transition from the Final Neolithic

Heat transfer properties of post-medieval crucibles

In the present case study, the thermal conductivity of two post-medieval crucibles was determined. The investigated crucible fragments represented two broadly contemporary production sites, Großalmerode and Obernzell, which were employing different types of raw materials (sand tempered kaolinitic clays and natural graphitic clays, respectively) and different firing conditions. The samples were part of a larger assemblage, which had been studied in view of production technology and function of pyrotechnical ceramics in post-medieval Europe and in view of dissemination of products from different production centers. The study results were expected to provide complementary information regarding the technology and use of the crucible

The circulation and consumption of Red Lustrous Wheelmade Ware: petrographic, chemical and residue analysis

yesRed Lustrous Wheelmade ware is one of the most recognisable classes of pottery from the Late Bronze Age of the east Mediterranean. Yet both its production source and the nature of its contents and use remain a source of some debate. These questions are tackled here through an intensive programme of scientific analysis involving 95 samples of Red Lustrous Wheelmade ware and related wares from seven sites in Turkey, Cyprus and Egypt. Petrography and instrumental neutron activation analysis are combined in the study of the ceramic fabrics, with a view to specifying the source of this ware; while gas chromatography and gas chromatography-mass spectrometry are used to analyse absorbed and visible residues in and on the sherd samples, in the hope of shedding light on vessel contents and possible use. The results of the fabric analysis show the ware to be extremely homogeneous, indicative of a single source: northern Cyprus is at present the most likely candidate, although further analysis, particularly of clay samples from the region in question, would certainly be desirable. The residue analysis suggests that Red Lustrous Wheelmade ware might have been used to carry some kind of plant oils, possibly perfumed, and that in some instances the vessel interior was coated with beeswax as a sealant.AHR

A contribution to the study of post-depositional alterations of pottery using TL dating analysis

In luminescence dating, the potassium concentration significantly contributes to the dose rate value in the age estimation. Within this study, fine-grain thermoluminescence dating has been applied on sherds of calcareous pottery of known age, excavated at a Roman site in Mallorca, Spain. For those of the samples that showed signs of severe potassium leaching, according to chemical and mineralogical examination, the thermoluminescence analysis provided overestimated dates. By using the known archaeological age of the samples, a corrected dose rate value can be estimated which provides the potassium concentration averaged for the burial period. Finally, a step-like model can then be used to estimate the fraction of the burial period after which most of the alteration effects took place

Production technology of glazed pottery in Chalcis, Euboea, during the Middle Byzantine period

This paper focuses on various categories of glazed pottery, which were in circulation in western Euboea (Greece) during the Middle Byzantine and Late Byzantine periods. The production technology and particularly the surface treatment of Byzantine glazed pottery have been investigated on the basis of 56 ceramic fragments from a rescue excavation in Orionos street in Chalkis, Euboea. This paper focuses on the manufacture of glazed pottery within the local pottery repertoire of Chalkis, while trying to contextualise the pottery typology and to consider the issues of technology. The chemical analysis by non-invasive energy dispersive X-ray fluorescence (XRF) and Scanning electron microscopy (SEM-EDS) provided information about the compositional variation of the examined glazed ceramics assemblage. Moreover, sections of the samples were examined by optical microscopy and scanning electron microscopy (SEM) in order to determine the microstructure of the samples, as well as the vitrification and the porosity of the ceramic body. Finally, X-ray diffraction (XRD) was applied for qualitative mineralogical analysis indicating presence or absence of high temperature phases and information about firing conditions.Roman Provinces, Middle Ages and Modern Perio

Think Globally, Act Locally: Global Requirements and Local Transformation in Sugar Pots Manufacture in Sicily in the Medieval and Post-Medieval Periods

Since medieval times, sugar production and consumption has had a huge impact on European social, cultural, and economic development. The introduction of sugar cultivation entailed knowledge transfer and new technological requirements, such as the manufacture of sugar pots used to crystallise sugar, which requires a specific design, and thermal and mechanical properties. This paper presents part of the results of the SPotEU project, funded under the Marie Skłodowska-Curie Actions, which explores the development and impact of sugar production in western Europe through the study of sugar pot manufacture from an interdisciplinary perspective, integrating archaeological and historical research with material science and material culture approaches. This paper focuses on sugar pots from Sicily, one of the main regions for sugar production in Western Europe in the 11-16th centuries A.D. Sugar pots were assessed from technological and performance points of view, aided by instrumental analysis (petrography, SEM, XRF, XRD, mechanical, and thermal property tests). The archaeological and analytical results are presented, revealing different centres of sugar pot production on the island, and specific choices in the design of the vessels and their properties. This allows us to discuss how craftspeople locally adapted their ceramic-making traditions to face the new product demands from the sugar production industry in the Mediterranean

Standardisation of elemental analytical techniques applied to provenance studies of archaeological ceramics: an inter laboratory calibration study

Chemical analysis is a well-established procedure for the provenancing of archaeological ceramics. Various analytical techniques are routinely used and large amounts of data have been accumulated so far in data banks. However, in order to exchange results obtained by different laboratories, the respective analytical procedures need to be tested in terms of their inter-comparability. In this study, the schemes of analysis used in four laboratories that are involved in archaeological pottery studies on a routine basis were compared. The techniques investigated were neutron activation analysis (NAA), X-ray fluorescence analysis (XRF), inductively coupled plasma optical emission spectrometry (ICP-OES) and inductively coupled plasma mass spectrometry (ICP-MS). For this comparison series of measurements on different geological standard reference materials (SRM) were carried out and the results were statistically evaluated. An attempt was also made towards the establishment of calibration factors between pairs of analytical setups in order to smooth the systematic differences among the results

Efficient and stable air-processed ternary organic solar cells incorporating gallium-porphyrin as electron cascade material

Two gallium porphyrins, a tetraphenyl GaCl porphyrin, termed as (TPP)GaCl, and an octaethylporphyrin GaCl porphyrin, termed as (OEP)GaCl, were synthesized to use as an electron cascade in ternary organic bulk heterojunction films. A perfect matching of both gallium porphyrins’ energy levels with that of poly(3-hexylthiophene-2,5-diyl) (P3HT) or poly[N-9′-heptadecanyl-2,7-carbazole-alt-5,5-(4′,7′-di-2-thienyl-2′,1′,3′-benzothiadiazole)] (PCDTBT) polymer donor and the 6,6-phenyl C71 butyric acid methyl ester (PCBM) fullerene acceptor, forming an efficient cascade system that could facilitate electron transfer between donor and acceptor, was demonstrated. Therefore, ternary organic solar cells (OSCs) using the two porphyrins in various concentrations were fabricated where a performance enhancement was obtained. In particular, (TPP)GaCl-based ternary OSCs of low concentration (1:0.05 vv%) exhibited a ~17% increase in the power conversion efficiency (PCE) compared with the binary device due to improved exciton dissociation, electron transport and reduced recombination. On the other hand, ternary OSCs with a high concentration of (TPP)GaCl (1:0.1 vv%) and (OEP)GaCl (1:0.05 and 1:0.1 vv%) showed the poorest efficiencies due to very rough nanomorphology and suppressed crystallinity of ternary films when the GaCl porphyrin was introduced to the blend, as revealed from X-ray diffraction (XRD) and atomic force microscopy (AFM). The best performing devices also exhibited improved photostability when exposed to sunlight illumination for a period of 8 h than the binary OSCs, attributed to the suppressed photodegradation of the ternary (TPP)GaCl 1:0.05-based photoactive film

Chemical and mineralogical alteration of ceramics from a Late Bronze Age kiln at Kommos, Crete: the effect on the formation of a reference group

The formation of reference groups comprises an important procedure in chemical provenance studies of archaeological pottery. Material from ancient kilns is thought to be especially suitable for reference groups, as it comprises a definite unit of past production. Pottery from the Late Minoan IA kiln excavated at Kommos, Crete was analysed in order to produce a reference group in this important area of Minoan ceramic production. The samples were characterized by a combination of techniques providing information on the chemistry, mineralogy and microstructure of the ceramic body. Initially, the study was unable to establish, in a straightforward manner, a chemical reference group. Different ceramic pastes and a range of selective alterations and contaminations, affected by variable firing temperatures and burial environment, were shown to be responsible for the compositional variability. Procedures are described to compensate for such alterations and the perturbations in the data that they produce