Analysis of enamel ultrastructure in archaeology: The identification of Ovis aries and Capra hircus dental remains

Ultrastructural features of deep, intermediate and superficial enamel were quantitatively assessed for the mandibular first permanent molars of 10 specimens each of the domestic sheep (Ovis aries) and goat (Capra hircus). The means of a number of variables differed interspecifically at high levels of statistical significance, especially with regard to the enamel of intermediate depth. A canonical discriminant function analysis employing nine variables at all three enamel depths resulted in the correct taxonomic assignment of 95% of the specimens comprising the present sample. These results, coupled with the simple preparative and analytical methods presented here, may enable archaeozoologists to utilize enamel ultrastructure in order to discriminate between fragmentary dental remains of these caprine species.     

Physico‐Chemical Characterization of Pigments and Binders of Murals in a Church in Ethiopia

Here, we report the physico‐chemical characterization of wall paintings from the Petros and Paulos church in Ethiopia. This work represents the first technical study of paintings located in Ethiopia, rather than paintings in museum collections outside the country, using diverse analytical techniques. In situ examination with a portable X‐ray fluorescence spectrometer (pXRF) was followed by analysis of samples using optical microscopy (OM), scanning electron microscopy coupled with energy‐dispersive X‐ray spectroscopy (SEM/EDS), micro‐Raman spectroscopy (MRS), attenuated total reflection – Fourier transform infrared spectroscopy (ATR‐FT–IR), X‐ray powder diffraction (XRD) and pyrolysis gas chromatography – mass spectrometry (Py‐GC/MS). The paint stratigraphy, the compositions of the support material, the preparatory and painting layers were studied, as well as the morphology of the pigment particles. The results revealed the use of earth pigments and carbon black. The preparatory layer was uncommon; composed of dolomite, clay rich in clinochlore and sand, in contrast to the more common gypsum and calcite. The binder and the stratigraphic analyses suggested a distempera technique.     

Micro‐Raman And Micro‐Stratigraphic Analysis Of The Painting Materials In The Rock‐Hewn Church Of The Forty Martyrs In Şahinefendi,Cappadocia (Turkey)

This paper presents the results of analyses carried out on the paintings on the rock‐hewn walls of the Forty Martyrs church at ?ahinefendi in Cappadocia (a UNESCO World Heritage Site), a central region of Turkey, performed during conservation work from 2007 to 2012. The micro‐samples were investigated by spectroscopic, micro‐stratigraphic and scanning electron microscopy analysis in order to study the painting technique, the materials and the degradation products. The micro‐stratigraphic analysis showed a white, sometimes pinkish, plaster. Micro‐Raman analysis, performed on cross‐sections of the mortars, enabled the detection of calcite, gypsum, anhydrite and calcium oxalate. Scanning electron microscopy and energy‐dispersive spectroscopy revealed a similar composition among all investigated phases, aside from minor differences such as the presence of diatoms in the second and third phases and of biotite, lime lumps and plants fragments in the fourth one. Apart from traditional pigments of medieval wall paintings, micro‐Raman analysis revealed the presence of lead‐based compounds and jarosite.     

Accuracy evaluation of the semi-automatic 3D modeling for historical building information models

It is stated that 3D recording and modeling of heritage buildings entail accurate building models (as-built). However, this paper presents an analysis of the 3D modeling accuracy for the creation of historical building information models (HBIM), considering the complexity and the deformations of historical buildings, using point cloud data and BIM tools. The 3D modeling processes analyzed are based on a three-stage semi-automatic approach leading to the generation of HBIM, including manual and automatic processes. The three stages consist of: (a) optical and terrestrial laser scanning; (b) meshing processes; and finally (c) 3D solid modeling to be assembled into HBIM. Next, this approach analyzed the mesh deformations generated automatically in comparison to the initial point cloud data. The deformations and the accuracy evaluation have been undertaken using different commercial software. Finally, our modeling approach shows that it can improve the accuracy of the 3D models achieved using existing BIM technologies.     

An Early Portuguese Mariner's Astrolabe from the Sodré Wreck‐site,Al Hallaniyah,Oman

A unique leaded‐gunmetal disc decorated with iconic Portuguese markings was recovered in 2014 during archaeological excavations at the Sodré shipwreck site in Al Hallaniyah, Oman. Initially the identity and function of the disc was unknown, although it did possess characteristics suggesting it could be an astrolabe. Laser imaging of the disc post conservation revealed regular scale marks on the limb of its upper right quadrant. Accurate digital measurements of the marks show them to be graded at close to 5‐degree intervals, thus confirming the identity of the disc as a mariner's astrolabe and the earliest known example discovered to date.     

Modeling and deterioration mapping of façades in historical urban context by close-range ultra-lightweight UAVs photogrammetry

Deterioration mapping of façades may be a challenging task in historical urban contexts, often characterized by narrow streets and tall buildings. In these situations, the application of Terrestrial Laser Scanning or Terrestrial Photogrammetry does not provide satisfactory results. Furthermore, the use of Unmanned Aerial Vehicles, the so-called “drones”, is generally forbidden in crowded places for safety reasons unless they are lighter than a weight imposed by the regulations in force in each country. This article presents the application of a very small and ultra-lightweight drone (less than 300 g) equipped with a low-cost camera, particularly suitable for operating in very narrow spaces. A close range photogrammetric survey performed to analyze a huge historical building façade in Bologna (Italy) pointed out a good accuracy level, confirmed by the validation of the results carried out by a 3D laser scanner survey. Moreover, a map of the degradation has been realized to support further restoration analysis, demonstrating that this low-cost, fast, and easy-to-use survey technique can be applied to other similar urban contexts at the same time.     

Thermodynamic study of capillary pressure curves based on free energy minimization

This paper presents a new method for pore level network simulation of the distribution of two immiscible phases in a permeable medium. The method requires that the Helmholtz free energy of the system — the medium and the two phases contained within the pore space — be a minimum at all saturation states. We describe the method here and show some typical results from a computer algorithm that implements it. The results include (i) an explanation of the ‘scanning’ behaviour of capillary pressure curves based wholly on the free energy minimization, (ii) predictions of capillary pressure at arbitrary wetting states, including negative capillary pressures, and (iii) illustrations of how the minimized free energy changes along the scanning curves. The method also predicts the known dependency of the capillary pressure on the pore size distribution and interfacial tension. The current work is restricted to two‐dimensional networks, but the free energy minimization appears to be generalizable to three dimensions and to more than two fluid phases. Moreover, functions generated through the minimization, specifically contact areas between the medium surface and the phases, appear to have applications predicting other multiphase petrophysical properties.     

Scanning electron microscope analysis of sediments from Tabun Cave,Mount Carmel,Israel

Scanning electron microscope analysis of sediments from Tabun Cave has revealed a detailed palaeoenvironmental history for the area. Basal units (Garrod's F and G layers) derive from wind-blown materials, intermediate units (E) are wind-blown derivatives but with marine modification, and the upper units (D, $\text{B}\text{C}$) exhibit only aeolian modification to grain surfaces. As had been previously postulated, the analyses also provide supporting evidence for chemical alteration phases within the sediments.     

The application of 3D laser scanning technology to the assessment of ordinal and mechanical cortex quantification in lithic analysis

Recent studies make use of cortex proportion as a proxy measurement for the impact of artefact transport on assemblage formation. Cortex in these studies is measured on an ordinal scale and analysed in relation to mechanical measurements of artefact size. Here we report on the use of a 3D laser scanner to obtain precise measurements from experimental lithic reduction sets. High-resolution measurements of cortex area are compared to measurements obtained through ordinal approximations of cortex proportion and mechanical approximations of artefact size. While the ordinal and mechanical measurements result in considerable error for individual artefacts, estimates improve significantly as sample size increases.     

Terrestrial laser scanning intensity data applied to damage detection for historical buildings

This paper presents a methodology to combine the technology of the terrestrial laser scanner with the techniques of digital image processing in order to study damages on stony materials that constitute historical buildings. This methodology has been tested using intensity data from three terrestrial laser scanners with different technical specifications. The unsupervised classification algorithms were used for the classification of 2D intensity images derived from the 3D information obtained from laser scanner equipment. The results obtained show the potential of the use of intensity data from terrestrial laser scanner for the recognition and characterization of certain pathologies in building materials that constitute historical buildings.