Floor Spectra of MDOF Nonlinear Structures

In this article, the influence of nonlinear behavior of multiple degree of freedom (MDOF) primary structures on floor response spectra is investigated by means of simple structural models. The cases of shear beam type as well as of capacity-designed plane frames were studied. It is shown that, in general, but not always, nonlinearity of the primary structure has a beneficial effect on floor spectra. However, higher mode response may be amplified due to nonlinear behavior. The issue of a one story structure exhibiting torsionnal response has also been addressed and some important properties are highlighted.     

Ancient-DNA reveals an Asian type of Mycobacterium leprae in medieval Scandinavia

Leprosy is a chronic infection of the skin and peripheral nerves caused by the pathogen Mycobacterium leprae. Its impact on human populations and societies of the past as well as its phylogeographic patterns around the world – at least in modern times – has been well documented. This slow growing bacterium has been shown to exist in distinct ‘SNP types’ that occur in relatively defined parts of the globe. The routes that the disease followed in the past are, however, still uncertain. This study of ancient-DNA typing of archaeological human remains from Sweden dated to early Medieval times provides genetic evidence that a transmission of M. leprae ‘SNP subtype’ 2G – found mainly in Asia – took or had already taken place at that time from the Middle East to Scandinavia. This finding is unique in the history of leprosy in Europe. All human specimens from this continent – both modern and ancient – that have been tested to date showed that the one responsible for the infection strains of M. leprae belong to ‘SNP type’ 3, whereas our results show that there were some European populations that were hosts to bacteria representing ‘SNP type’ 2 of the species as well.     

Constructing Identities in Early Iron Age Thessaly: The Case of the Halos Tumuli

This paper examines the Early Iron Age tumulus–cemetery of Halos in south–eastern Thessaly, with its unique cremation pyre–cairn combination. As there are no parallels for such combination of burial practices either in Thessaly or in any other area of the Greek world, it has usually been suggested that the tumuli were erected by people foreign to Thessaly, most probably of a northern origin. This paper presents evidence suggesting a local custom closely related to the desire to create a new identity.     

Surface dating by luminescence: An overview

Daylight radiation resets luminescence ‘clock’ to zero on rock surfaces, but transmission depends on the transparency of the rock. On burial, surfaces are no longer exposed to daylight and accumulation of trapped electrons takes place till the excavation. This reduction of luminescence as a function of depth fulfils the prerequisite criterion of daylight bleaching. Thus rock artefacts and monuments follow similar bleaching rationale as those for sediments. In limestone and marble, daylight can reach depths of 0.5–1 mm and up to 16 mm respectively, while for other igneous rocks e.g. quartz in granites, partial bleaching occurs up to 5mm depth under several hours of daylight exposures and almost complete beaching is achieved in the first 1 mm within about 1 min daylight exposure. The ‘quartz technique’ for limestone monuments containing traces of quartz enables their dating with Optically Stimulated Luminescence (OSL) techniques. The surface luminescence (thermoluminescence, TL or OSL) dating has been developed and further refined on various aspects of equivalent dose determination, complex radiation geometry, incomplete bleaching etc. A historical review of the development including important applications, along with some methodological aspects are discussed.     

An Investigation of Ceramic Forming Method Using Reverse Engineering Techniques: The Case of Oinochoai from Dion, Macedonia, Greece

A method for investigating the forming technique of ancient ceramic vessels is presented. The recording, analysis, and comparison of the vessels' metrical properties by means of computer tomography, three-dimensional laser scanning, and solid-modeling software enables the identification of the applied manufacturing methods. A finite elements method-based simulation of the developed deformations during the vessels' manufacture offers significant insight into the applied shaping procedures. By making possible the exact recording of both the internal and external form of the vessels as well as the simulation of the forming procedure, the method represents a marked improvement to hitherto applied methods based on radiography. The method is applied on two early iron age ceramic jugs (oinochoai) found as offerings in tombs in excavations in Dion, Greece.     

Identification of organic materials in icons of the Cretan School of iconography

The Cretan School of iconography is the last great flowering of the traditional Byzantine painting manner, which is however influenced by different schools and western art. Despite their historical significance, icons of the Cretan School have been rarely studied through modern chemical techniques and therefore very few information is available on the materials used by the Cretan painters. In the present investigation, the organic materials contained in several icons of the Cretan School of Iconography from the collection of the Benaki Museum, Athens, Greece, are analyzed and identified by High Performance Liquid Chromatography coupled to a Diode Array Detector (HPLC–DAD) and Gas Chromatography with Mass Spectrometry (GC–MS).The HPLC–DAD results provide support to a recently published report which showed that kermes used in “Cretan” icons of 15th century and early 16th century was replaced by cochineal which was used in icons dated after early 16th century. This trend is known for western art and it is now proved for Cretan icons, showing thus the influence of the Cretan painters by other European painting schools. Other dyes detected in the historical samples, extracted from Cretan icons are madder (possibly Rubia tinctorum L., according to HPLC profiles) and indigoid dyes. Oils, such as linseed and walnut oil, are identified in samples extracted from the seven icons tested by GC–MS. Egg yolk is identified in the extract of only one icon and animal glue, originated most likely from the gesso ground, is found in six samples. Other organic materials detected by GC–MS were wax, as well as synthetic resins, applied during conservation treatments.     

Identification of materials in post-Byzantine textiles from Mount Athos

Numerous textiles of inestimable historical significance have been preserved in the monasteries of Mount Athos for several centuries. However, our knowledge regarding the materials used in these objects is very limited. In the present study, microsamples extracted from ecclesiastical textiles (16th – 19th c.) of the monastery of Xeropotamou (Mount Athos) are investigated using Optical Microscopy (OM), Fourier Transform Infrared Spectroscopy (FTIR), High Performance Liquid Chromatography coupled to a Photodiode Array Detector (HPLC-PDA) and Scanning Electron Microscopy equipped with an Energy Dispersive X-ray spectrometer (SEM-EDX). The first goal of the study is to identify the colouring materials of the historical samples, which were of silk nature (OM). The presence of Prussian blue is revealed using FTIR and organic colourants such as cochineal, dyer’s broom (Genista tinctoria L.), fuchsin, indigo carmine, old fustic (Chlorophora tinctoria L.), soluble redwood (Caesalpinia trees), weld (Reseda luteola L.), young fustic (Cotinus coggygria Scop.) and indigoid dyestuff source(s) are identified using HPLC-PDA. Dyestuff extraction from silk substrates is achieved using the TFA method, which preserves the contained glycosides. Thus, the report provides further evidence to support the efficacy of the TFA method to extract various organic colourants from historical silk samples (second goal). Finally, metal threads included in some historical samples are studied using OM and SEM-EDX. The latter is employed to analyse the composition of the metal surfaces. Silver (Ag) and gold (Au) are detected on the surfaces of the majority of the samples. Two samples were manufactured only with Ag.