Reflectance - Current state of research and future directions for archaeological charcoal; Results from a pilot study on Irish Bronze Age cremation charcoals

‘Reflectance’ is a method that estimates the absolute burn temperature of charcoal from the ‘shininess’ of resin mounted samples. The method's usefulness for archaeological charcoal is yet to be comprehensively studied. This article details first results from reflectance testing of archaeological charcoals excavated from Irish Bronze Age cremations, which included calcined bone. As calcination of bone commences at 650 °C, it was expected that the charcoals would reflect at least this temperature. This was not the case for taxonomically identified charcoals >2 mm, nor for micro-charcoals of c. 250 μm, although measured temperatures rose slightly with decreasing fraction size of charcoal remains. Depositional practice, combustion completeness and taphonomic influences may have all played a part in this result, and these will need careful consideration in different archaeological circumstances. However, the greatest challenge for reflectance of archaeological materials lies in obtaining full agreement on the production and use of reflectance calibration curves. Current calibration curves differ substantially, by 100–150 °C (±50–75 °C) and in one instance up to as much as 180 °C (±90 °C). Without better agreement on calibration, the method's ultimate usefulness in archaeological research will be limited. At the level of refinement currently possible, it will still be useful for determining very high or very low temperature processes, and possibly the difference between charcoal fuel and raw wood fuel fires. The latter has distinct implications for estimating ancient forest wood consumption, since more wood is consumed in processes employing charcoal fuel. Proving the utility of reflectance for archaeological purposes may also require modification of normal practice for archaeological field collection of charcoal, to include collection and laboratory processing of un-sieved soil samples.The authors acknowledge the support of the CSIRO, Sydney; the Department of Archaeology, and the Australian Centre for Microscopy and Microanalysis, University of Sydney (especially materials preparation specialist, Mr Adam Sikorski); and the McDonald Institute for Archaeological Research, University of Cambridge. Excavations were carried out by Margaret Gowen & Co. Ltd, funded by the National Roads Authority, Ireland. This research was partly funded by the Government of Ireland, Irish Research Council (Project id GOIPD/2013/387) supported by the School of Archaeology, University College Dublin

Fuel in ancient food production

Fuel is a little considered part of the ancient economy. The production and consumption of food constituted one of the major uses of fuel in the Greco-Roman world. It was required on an industrial scale in bakeries, temples and probably bars, but it was also required daily in people’s homes mostly for cooking food (in the kitchen, and in the triclinium), and also for sacrificing to the Lares. Wood and wood charcoal were the main fuels in the Roman world, but non-wood fuels including agricultural waste (especially olive pressings), were also consumed. This paper reviews the types of fuel used in the preparation of food, both commercially and domestically, with reference to examples from the Greco-Roman world, especially Pompeii. The relative heat values of different fuels are discussed, together with an overview of the supply constraints and probable volumes required.This discussion summarizes work funded by The D.M. McDonald Grant Fund, and completed at, the McDonald Institute for Archaeological Research, University of Cambridge, as well as the Department of Archaeology, University of Sydney

Accelerating the development of new solar absorbers by photoemission characterization coupled with density functional theory

The expectation to progress towards Terawatts production by solar technologies requires continuous development of new materials to improve efficiency and lower the cost of devices beyond what is currently available at industrial level. At the same time, the turnaround time to make the investment worthwhile is progressively shrinking. Whereas traditional absorbers have developed in a timeframe spanning decades, there is an expectation that emerging materials will be converted into industrially relevant reality in a much shorter timeframe. Thus, it becomes necessary to develop new approaches and techniques that could accelerate decision-making steps on whether further research on a material is worth pursuing or not. In this review, we will provide an overview of the photoemission characterization methods and theoretical approaches that have been developed in the past decades to accelerate the transfer of emerging solar absorbers into efficient devices

Intrinsic electronic superconducting phases at 60 K and 90 K in double-layer YBa2_2Cu3_3O6+δ_{6+\delta}

We study superconducting transition temperature ($T_c$) of oxygen-doped double-layer high-temperature superconductors YBa$_2$Cu$_3$O$_{6+\delta}$ (0 $\le$ $\delta$ $\le$ 1) as a function of the oxygen dopant concentration ($\delta$) and planar hole-doping concentration ($P_{pl}$). We find that $T_c$, while clearly influenced by the development of the chain ordering as seen in the $T_c$ $vs.$ $\delta$ plot, lies on a universal curve originating at the critical hole concentration ($P_c$) = 1/16 in the $T_c$ $vs.$ $P_{pl}$ plot. Our analysis suggests that the universal behavior of $T_c$($P_{pl}$) can be understood in terms of the competition and collaboration of chemical-phases and electronic-phases that exist in the system. We conclude that the global superconductivity behavior of YBa$_2$Cu$_3$O$_{6+\delta}$ as a function of doping is electronically driven and dictated by pristine electronic phases at magic doping numbers that follow the hierarchical order based on $P_c$, such as 2 $\times$ $P_c$, 3 $\times$ $P_c$ and 4 $\times$ $P_c$. We find that there are at least two intrinsic electronic superconducting phases of $T_c$ = 60 K at 2 $\times$ $P_c$ = 1/8 and $T_c$ = 90 K at 3 $\times$ $P_c$ = 3/16.Comment: 4 pages, 2 figure

Pension Accounting And Reporting With Other Comprehensive Income And Deferred Taxes: A Worksheet Approach

This instructional tool presents pension accounting using a worksheet approach where debits equal credits for both the employer and for the plan. Transactions associated with the initiation of the plan through the end of the second year of the plan are presented, including their impact on accumulated other comprehensive income and deferred taxes. This article is intended as a supplemental teaching tool that demonstrates the impact of a plan’s funded status on the employer’s financial statements in a way that, based upon anecdotal evidence, accounting students and practitioners have found extremely beneficial beyond traditional accounting textbooks

Surface electronic properties of undoped InAlN alloys

The variation in surface electronic properties of undoped c-plane InxAl1−xN alloys has been investigated across the composition range using a combination of high-resolution x-ray photoemission spectroscopy and single-field Hall effect measurements. For the In-rich alloys, electron accumulation layers, accompanied by a downward band bending, are present at the surface, with a decrease to approximately flatband conditions with increasing Al composition. However, for the Al-rich alloys, the undoped samples were found to be insulating with approximate midgap pinning of the surface Fermi level observed

Drivers of success in implementing sustainable tourism policies in urban areas

The existing literature in the field of sustainable tourism highlights a number of barriers that impede the implementation of policies in this area. Yet, not many studies have so far considered the factors that would contribute to putting this concept into practice, and few address the case of urban areas. The concept of sustainability has only received limited attention in urban tourism research, even though large cities are recognised as one of the most important tourist destinations that attract vast numbers of visitors. Adopting a case study approach, this paper discusses a number of drivers of success identified by policy-makers in London to contribute to the implementation of sustainable tourisms policies at the local level, and briefly looks at the relationship between these drivers and the constraints perceived by the respondents to hinder the implementation of such policies in practice. These findings may help policy-makers in other large cities to successfully develop and implement policies towards sustainable development of tourism in their area

Plow Power Requirements for Forestry Site Preparation

In this field study, data were collected to determine power requirements required by a trailing site preparation plow and the magnitudes of dynamic forces experienced by a plow during normal operation and during impact with stumps or other obstructions. Drawbar pull data were collected from five different tillage treatments on a recently harvested loblolly pine (Pinus taeda) site in central Alabama. The five treatments were: 1) a coulter, ripping shank, and four bedding disks; 2) a coulter, ripping shank, and two bedding disks; 3) a coulter and ripping shank; 4) a coulter alone; and 5) a ripping shank alone. A 330 kN [75 000 lb] capacity tension load cell was used to measure the drawbar load, a GPS receiver recorded tractor speed, four direct current displacement transducers (DCDT's) monitored the depth of the disks, and two optical tachometers measured the speed of the tractor's front and rear drive shafts. Each treatment produced significantly different drawbar loads (to alpha levels less than 0.001). The resulting mean loads were 46.0 kN [10 300 lb], 33.5 kN [7530 lb], 31.5 kN [7080 lb], 15.8 kN [3560 lb], and 43.4 kN [9760 lb] for treatments one through five, respectively. Maximum recorded drawbar load during a collision with a stump was 338.9 kN [76 188 lb]