Nano-CT evaluation of totally corroded coins: A demonstration study to determine if detail might still be discernible despite the lack of internal,non-corroded,metal

Five unidentifiable, completely corroded ancient coins (three of which were large fragments), proven to lack any residual internal metal, were scanned by nano-computed tomography (CT) to see if discernible detail might still be present. One fragment could be identified as an early fourth-century Urbs Roma commemorative AE 3/4. Another fragment was a coin of either Valerian or of the joint rule of Valerian and Gallienus, which could be dated to the period 254–56 ce . The other three lacked discernible detail. This proof-of-concept study shows that nano-CT scanning has the potential to allow non-invasive identification of at least some totally corroded coins.     

Between east and west: Glass beads from the eighth to third centuries bce from Poland

The study analyses the chemical composition of 57 glass samples from 40 beads discovered at 20 archaeological sites in Poland. The beads are dated to Hallstatt C–Early La Tène periods (c.800/750–260/250 bce ). Analyses were carried out using laser ablation-inductively coupled plasma-mass spectrometry (LA-ICP-MS). Two groups were distinguished among the glasses based on the MgO/K₂O ratio: high-magnesium glass (HMG), five samples; and low-magnesium glass (LMG), 52 samples. The former were melted with halophyte plant ash, the second with mineral soda. These glasses were produced in the Eastern Mediterranean (more likely in Mesopotamia or Syro-Palestine than in Egypt) and transported in the form of semi-products to secondary glass workshops in Europe. Some of the white opaque glass was coloured and opacified in Europe.     

Drawing the line with Google Earth: the place of digital mapping outside of geography

The Te Kawa a Māui Atlas project explores how mapping activities support undergraduate student engagement and learning in Māori studies. This article describes two specific assignments, which used online mapping allowing students to engage with the work of their peers. By analysing student evaluations of these activities, we identify four aspects that benefit student engagement: mapping diversifies the learning experience; mapping promotes acquisition of a different skill set; online mapping allowed more open sharing of work and; mapping promotes place-based learning. Some students were ambivalent about the assignments, so mapping should only be used to support other learning objectives.     

Negotiations of Irish identity in the wake of terrorism: the case of the Irish in Birmingham 1973–74

This article explores the Irish migrant experience in Birmingham during and in the wake of terrorist campaigns carried out in Britain between 1969 and 1975 and attributed to the Irish Republican Army (IRA). Beginning with a discussion of the competencies with which Irishness was associated at the close of the 1960s in England, many of which were hinged on a notion of the Irish predisposition towards violence, the article continues on to take the political, cultural and religious “temperature” of the Irish community in Birmingham between 1969 and 1975, and follows on with a discussion of the specific strategies sought out by Irish immigrants to come to terms with the effect of events such as the “Birmingham Bombings” on their daily lives. Principle findings that emerge from the study indicate that IRA terrorism forced the Irish in Birmingham to engage with and adopt a number of distinct linguistic and cultural strategies in the post-1974 period, the cultivation of which indefinitely altered their relationship with Ireland as “home”, their visibility in the public British sphere and their associational patterns and practices within the migrant enclave.     

A Rock‐Magnetic Quest for Possible Ore Sources for the Ancient Iron‐Smelting Industry in the Olkhon Region (Lake Baikal,Siberia)

Rock‐magnetic techniques were used to examine the topsoil layer of Kurma archaeological site (in the Olkhon region, on the north‐western coast of Lake Baikal, Siberia) in an effort to determine the possible sources of iron ores for iron‐smelting centres (at about the bc /ad boundary). Measurements have shown a magnetic enhancement of the topsoil due to magnetite grains resulting from weathering of strongly magnetic crystalline rocks. They have also revealed a preliminary picture of the distribution of strongly magnetic topsoils around the ancient iron‐smelting centres. Perhaps, in addition to traditional sources of raw materials, the ancient metallurgists used black sand talus as an ore deposit.     

Permeability changes in simulated granite faults during and after frictional sliding

Thermal–hydrological–mechanical coupling processes suggest that fault permeability should undergo dynamic change as a result of seismic slip. In igneous rocks, a fault's slip surface may have much higher permeability than the surrounding rock matrix and therefore operate as a conduit for fluids. We conducted laboratory experiments to investigate changes in fracture permeability (or transmissivity) of a fault in granite due to shear slip and cyclic heating and cooling. Our experiments showed that high initial fracture transmissivity (>10^?18 m³) was associated with a high friction coefficient and that transmissivity decreased during slip. We propose that this reduction in transmissivity reflects the presence of gouge in fracture voids, increasing the area of contact in the fault plane and reducing the hydraulic aperture. In contrast, when initial fracture transmissivity was low (<10^?18 m³), we observed that friction was lower and transmissivity increased during slip. The high transmissivity and high friction may be explained by large areas of bare rock being in contact on the slip surface. Slip velocity had little influence on the evolution of permeability, probably because gouge produced at different slip velocities had similar grain size distributions, or because gouge leaked from the slip surface. Transmissivity decreased with increasing temperature in heating tests, probably due to thermal expansion increasing normal stress on the fracture. Frictional heating did not influence transmissivity during the shearing tests.