Is X-ray diffraction able to distinguish between animal and human bones?

The possibility of determining the human or animal origin of bones from the lattice parameters of their inorganic bioapatite phase, when subjected to a high temperature treatment using the powder X-ray diffraction (XRD) technique, has been explored on a wide number of specimens. Forty-two animal bones were treated in a furnace at 1100 °C for 36 min and compared to 53 cremated human bones from a range of ancient necropolises. The X-ray diffraction patterns of bioapatite were simulated using both monoclinic P21/b and hexagonal P63/m structures to verify any occurrence of phase transformation and any difference in the lattice parameters due to the model. It was determined that the differences between the a-axis and c-axis of the monoclinic and hexagonal lattice were unimportant. Some outlying values were revealed to be caused by the presence of chlorine ions diffused into the apatite structure increasing its average unit cell values. Nevertheless, our results clearly show that in terms of lattice parameters the variability of human specimens are completely overlapped by the non-human variability making the use of XRD in order to distinguish animal from human bones questionable.     

Physical and Numerical Approaches for the Optimal Insertion of Seismic Viscous Dampers in Shear-Type Structures

This article presents the results of an exhaustive parametric analysis which compares the performances offered by various systems (which lead to both classical and non classical damping matrices) of added viscous dampers in shear-type structures. The aim of the research work here presented is the identification of the system of added viscous dampers which maximizes the dissipative properties under an equal “total size” constraint. The choice of the systems of added viscous dampers considered in the comparison is carried out both using a numerical approach (based upon the use of genetic algorithms) and a physically based approach (based upon the properties of classically damped systems). The comparison is carried out through the numerical evaluation of the dynamic response of representative shear-type structures to both stochastic and recorded earthquake inputs. The results obtained using both approaches indicate that a damping system based upon the mass proportional damping component of the Rayleigh viscous damping matrix (referred to as MPD system) is capable of optimizing simultaneously a number of different performance indexes, providing the best “overall” damping performances. The MPD system is characterised by viscous dampers (a) which connect each floor to a fixed point and (b) which are sized proportionally to the corresponding floor mass.     

A spotted hyaena den in the Middle Palaeolithic of Grotta Paglicci (Gargano promontory,Apulia, Southern Italy)

The Palaeolithic sequence of Grotta Paglicci (Gargano promontory, Apulia, Southern Italy) is one of the most important in the Mediterranean area: It comprises the whole Upper Palaeolithic cultural sequence known for the region, as well as Early Middle Palaeolithic and Lower Palaeolithic levels. These earlier phases are best represented in a collapsed room located outside the present-day cave (the so called “external rock shelter”). In this area, a new excavation, started in 2004, brought to light Middle Palaeolithic animal remains associated with evidence of spotted hyaena (SU 64 and 53). The spatial distribution analysis of remains from SU 53 revealed the presence of a bone accumulation area and a wider dispersal of hyaena coprolites. Three main ungulate species (aurochs, fallow deer and red deer) as well as carnivores (spotted hyaena, wolf, fox, wild cat and lynx) and lagomorphs have been identified. The majority of aurochs remains are located in the main accumulation; among these specimens, a complete metatarsal connected with three tarsal bones has been found; a talus and a complete tibia, probably belonging to the same limb, have also been identified. The multidisciplinary study carried out in this paper highlights a specific bone accumulation and scattering pattern in a spotted hyaena (Crocuta crocuta) den. In addition, taphonomy of lagomorph remains indicates the presence of other depositional agents.     

Masonry Italian Code-Conforming Buildings. Part 2: Nonlinear Modelling and Time-History Analysis

ABSTRACT

The unreinforced masonry (URM) buildings designed to be conforming with the Italian building code, as illustrated in the companion paper, were analyzed by performing time-history analyses on models realized using an equivalent frame approach and by adopting two different constitutive laws. Both the effect of record-to-record variability and of epistemic and aleatory uncertainties in modelling were explored. The achieved results constitute the basis for the evaluation of the risk level implicit in Italian code-conforming buildings. Two main performance conditions are considered, namely usability-preventing damage and global collapse limit states.     

A Five-Step Procedure for the Dimensioning of Viscous Dampers to Be Inserted in Building Structures

Viscous dampers have widely proved their effectiveness in mitigating the effects of the seismic action upon building structures. In view of the large impact that use of such dissipative devices is already having and would most likely have soon in earthquake engineering applications, this article presents a practical procedure for the seismic design of building structures equipped with viscous dampers, which aims at providing practical tools for an easy identification of the mechanical characteristics of the manufactured viscous dampers which allow to achieve target levels of performances. Selected numerical applications are developed with reference to simple, but yet relevant, cases.     

Post-Tensioned Glulam Beam-Column Joints with Advanced Damping Systems: Testing and Numerical Analysis

This article describes tests investigating a feasible source of passive damping for post-tensioned glue-laminated (glulam) timber structures. This innovative structural system adapts precast concrete PRESSS technology [Priestley et al., 1999] to engineered wood products combining the use of post-tensioned tendons with large timber members. Current testing is aimed at further improvement of the system through additional energy dissipation. Testing has favorably compared glue-laminated timber (not previously implemented in this way) with laminated veneer lumber (LVL) used in New Zealand. After initial benchmark testing with post-tensioning only, a simple, minimally invasive and replaceable type of hysteretic damper was added.     

Holocene Deposits of Saharan Rock Shelters: The Case of Takarkori and Other Sites from the Tadrart Acacus Mountains (Southwest Libya)

The excavation at Takarkori rock shelter is part of a long-term study of Holocene cultural dynamics in southwest Libya begun in the early 1990s. With a rich Holocene occupation, the area is one of the key spots for reconstruction of human occupation of the last 10,000 years. In this region, similar to the case in the rest of the Sahara, most of the data come from surface investigations at open-air sites, while excavated caves and rock shelters provide just a few. Although less exposed than open-air sites, Holocene archaeological deposits in Saharan caves and rock shelters are characterized by a fairly dynamic nature. Loose sediments, coupled with variability of human occupations and magnitude of natural agents, determine multiple alterations to the archaeological deposits in sheltered sites. In this paper, we present the nature and meaning of the archaeological deposits at Takarkori rock shelter, where a relatively large area has been recently excavated, showing a stratigraphic sequence extending from c. 9,000 to 4,200 BP, unevenly represented by several occupation pulses. In order to sharpen understanding of the development of human occupation at this site, specific procedures for the study and recording of the archaeological deposit have been developed, along with a program of extensive radiocarbon dating. Data from the Takarkori sequence ultimately will be integrated with available published stratigraphies from the Acacus Mountains, with the aim of reviewing the results from past excavations.     

History and Ideology of an Akan Centre: The Cosmological Topography of Wiawso

This article documents in a specific setting, the Sefwi variant of the Akan civilization of West Africa, the complex interplay between history and ideology in the establishment of settlements’ hegemony. The text scrutinizes sources on specific historical circumstances concerning the transformation of Wiawso, the town chosen for this exercise of cosmological topography, over the last three centuries. The demographic, social, ritual and urban dynamics are discussed with reference to the semantics of the spatial dimension of Akan settlements’ hegemonic ambitions. The focus on the interplay between history and ideology elucidates two issues. First, the importance of strategic and historically‐specific evocation and display of objects, sites and narratives claiming reference to the past, in generating and mobilizing structures of signification sustaining Wiawso’s recognized prominence. Second, the persistence over time of certain Akan ideological features concerning principally what the past entails and the standards for evaluating settlements’ success in centralization.     

A new calibration of the XRD technique for the study of archaeological burned human remains

A new calibration of human bones as a function of programmed temperature (200–1000 °C) and time (0, 18 and 60 min) is presented and discussed in order to investigate the issues related to the study of cremated bone remains by using the powder X-ray diffraction approach. The experimental results confirm the growth of hydroxylapatite crystallites as a function of the applied temperature, with a sigmoid behaviour that has been parameterized to the experimental data points. Particularly, it was observed that the thermal treatments for 60 min anticipate of about 100 °C the effects that are otherwise observed after the treatments for 0 min. The developed procedure was subsequently applied to cremated remains of various archaeological sites of Spain and supplied precise information not only about the temperature reached during the funerary rites, but also on the presumed duration for the cremation.     

Earthquakes and Tie-Rods: Assessment,Design, and Ductility Issues

The effectiveness of tie-rods is widely stressed in past earthquakes and they are still used today as reinforcement intervention, given that their use is a low-invasive and low-expensive technique. However, the earthquake design of these devices is not so simple since the main feature of a tie-rod derives from its ductility and that should be preserved as was done in the past. In this article, some considerations about static and seismic design of tie-rods are made, highlighting the main failure modes of the system. To assess seismic vulnerability of I-mode mechanism, displacement-based methods are usually used, requiring high elongation capability of the tie-rods. For this reason, an experimental campaign was carried out to define clearly the maximum elongation of tie-rods and to investigate the influence of bar length on ductility. The results have shown a good displacement capacity that decreases with the increase of steel strength. A simplified formulation, obtained from nonlinear kinematic analysis, is derived to evaluate quickly the seismic vulnerability of I-mode mechanism with tie-rods and to design this common retrofitting intervention in existing buildings.