3D scanning by multiple fan beam X-ray sources and sensors

*** Purpose – Computer tomography (CT) for 3D reconstruction entails a huge number of coplanar fan-beam projections for each of a large number of 2D slice images, and excessive radiation intensities and dosages. For some applications its rate of throughput is also inadequate. A technique for overcoming these limitations is outlined. *** Design methodology/approach – A novel method to reconstruct 3D surface models of objects is presented, using, typically, ten, 2D projective images. These images are generated by relative motion between this set of objects and a set of ten fanbeam X-ray sources and sensors, with their viewing axes suitably distributed in 2D angular space. *** Findings – The method entails a radiation dosage several orders of magnitude lower than CT, and requires far less computational power. Experimental results are given to illustrate the capability of the technique *** Practical implications – The substantially lower cost of the method and, more particularly, its dramatically lower irradiation make it relevant to many applications precluded by current techniques *** Originality/value – The method can be used in many applications such as aircraft hold-luggage screening, 3D industrial modelling and measurement, and it should also have important applications to medical diagnosis and surgery.

Issues in the assimilation of the sources of a trace gas by inverse modelling

The problem of reconstructing the (otherwise unknown) source and sink field of a tracer in a fluid is studied by developing and testing a simple tracer transport model of a single-level global atmosphere and a dynamic data assimilation system. The source/sink field (taken to be constant over a 10-day assimilation window) and initial tracer field are analysed together by assimilating imperfect tracer observations over the window. Experiments show that useful information about the source/sink field may be determined from relatively few observations when the initial tracer field is known very accurately a-priori, even when a-priori source/sink information is biased (the source/sink a-priori is set to zero). In this case each observation provides information about the source/sink field at positions upstream and the assimilation of many observations together can reasonably determine the location and strength of a test source.

Detecting the environmental impact of the Baltic Crusades on a late-medieval (13th-15th century) frontier landscape: palynological analysis from Malbork Castle and hinterland, Northern Poland

Palaeoecological analysis of peat deposits from a small bog, combined with pollen analysis of sediments infilling the moat of the nearby Teutonic Order castle at Malbork, have been used to examine the ecological impact of the Crusades on the late-medieval landscape of Northern Poland. Studies of the environmental impact of the Crusades have been almost exclusively informed by written sources; this study is the first of its type to directly investigate the environmental context of Crusading as a force of ecological transformation on the late-medieval Baltic landscape. The pollen evidence from Malbork Castle and its hinterland demonstrate that the 12th/13th–15th centuries coincide with a marked transformation in vegetation and land-use, characterized by clearance of broadleaved woodland and subsequent agricultural intensification, particularly during the 14th/15th centuries. These changes are ascribed to landscape transformations associated with the Teutonic Order’s control of the landscape from the mid-13th century. Human activity identified in the pollen record prior to this is argued to reflect the activities of Pomeranian settlers in the area. This paper also discusses the broader palaeoecological evidence for medieval landscape change across Northern Poland.

Information sources and advice used by small business tenants when leasing commercial property

Many small businesses lease commercial premises. The terms of a lease can affect the ability of the business to grow and adapt and have an impact on cashflow. Ensuring that they have the information with which to negotiate terms is part of the UK government policy focus on small businesses. Such information is most effectively disseminated through the sources of advice that small businesses use during the leasing process. Therefore these sources of advice need identifying. An interview survey of small business tenants who have recently taken leases provides initial results that suggest small businesses do not seek out advice during the leasing process or see the need to be better informed. The only formal professional input is from solicitors but this is not until after the main commercial terms have been agreed. The landlords’ letting agents play a key, but ambiguous, role in providing information as well as advice. These results suggest that the most effective way of disseminating information by government could be via the letting agents, the very people with whom the tenants are negotiating.

A comparison of the relative toxicity of bone meal and other P sources used as remedial treatments to the earthworm Eisenia fetida

It has been suggested that sources of P could be used to remediate metal-contaminated soil. The toxicity of four potential P sources, potassium hydrogen phosphate (PHP), triple superphosphate (TSP), rock phosphate (RP) and raw bone meal (RBM) to Eisenia fetida was determined. The concentration of P that is statistically likely to kill 50% of the population (LC50) for PHP, TSP and RBM was determined in OECD acute toxicity tests. 14 day LC50s expressed as bulk P concentration lay in the range 3319–4272 mg kg−1 for PHP, 3107–3590 mg kg−1 for TSP and 1782–2196 mg kg−1 for RBM (ranges present the 95% confidence intervals). For PHP and TSP mortality was significantly impacted by the electrical conductivity of the treated soils. No consistent relationship existed between mortality and electrical conductivity, soil pH and available (Olsen) P across the PHP, TSP and RBM amendment types. In RP toxicity tests mortality was low and it was not possible to determine a LC50 value. Incineration of bone meal at temperatures between 200 and 300 ◦C, pre-washing the bone meal, co-amendment with 5% green waste compost and delaying introduction of earthworms after bone meal amendments by 21 days or more led to significant reductions in the bone meal toxicity. These results are consistent with the toxicity being associated with the release and/or degradation of a soluble organic component present in raw bone meal. Bone meal can be used as an earthworm-friendly remedial amendment in metal-contaminated soils but initial additions may have a negative effect on any earthworms surviving in the contaminated soil before the organic component in the bone meal degrades in the soil.