Surface-modified minerals for radionuclide sequestration

This thesis is concerned with experiments designed to identify materials to increase the utility of the Sellafield Ion Exchange Plant (SIXEP) process. Clinoptilolite, ZSM-5, vermiculite and kaolinite have been surface modified by grafting with APTES, TMSPE and TMSPETT ligands using varying grafting times (1-24 h), ligand concentrations (1-3 mmol) and solvents with different polarities (with dielectric constant between 1.9 80). Materials before and after grafting were analysed using long and short range techniques including elemental analysis (CHN), powder X-ray diffraction (PXRD), scanning electron microscopy (SEM), solid state nuclear magnetic resonance (SSNMR) and infra-red (FTIR) spectroscopy. The amount of graft placed on the surface increased with reaction time for all materials as the amount of carbon per unit mass of the support, determined by CHN analysis, increased with time. C-H stretches were consistently observed in the FTIR of the grafted materials but no change was observed to the long range order in the PXRD pattern. 13C SSNMR showed that small solvent molecules such as acetone can become trapped in the material supports during grafting and long drying times are required to ensure that trapped solvent molecules do not contaminate the CHN analyses of the materials after grafting. Clinoptilolite and vermiculite consistently achieved higher grafting levels than ZSM-5 or kaolinite, with clinoptilolite (NDA) showing the greatest carbon content of 56.16 mmol of APTES per gram of clinoptilolite using hexane as the solvent. Despite a similar molecular weight, TMSPE consistently showed lower levels of grafting than APTES. APTES grafting levels were increased by using citric, phosphoric and nitric acid (1-3 mol L-1) to pre-treat the surface of the materials over different time periods (1-24 h) to improve the level of APTES graft. While the carbon content was higher for acid treated clinoptilolite (NDA) after grafting, in the case of the citric acid treatment, this increase maybe due to the formation of iron (III) citrate from the dissolution of poorly crystalline iron impurities in the clinoptilolite (NDA). Ungrafted and grafted clinoptilolite, ZSM-5, vermiculite and kaolinite samples were investigated for their ability to sequester caesium, strontium, uranium and plutonium species. Absorption/desorption experiments were initially conducted on the ungrafted compounds using caesium and strontium cations to establish a baseline for the most abundant species in pond liquor. Caesium and strontium cations are trapped within the cages of clinoptilolite in an ion exchange reaction which places these ions on sites of the appropriate size and geometry for these species. Once ion exchanged, neither ion is desorbed from the clinoptilolite readily and they remain trapped inside the cage, irrespective of concentration of other species in solution. While vermiculite is also successful at removing both caesium and strontium cations, it is less successful in retaining them during desorption, with typically one third of the trapped ions being released back into solution. ZSM-5 and kaolinite have contrasting behaviour, due to few exchangeable cations, meaning caesium and strontium uptake is poor. Samples of clinoptilolite with different particle sizes and potassium content were compared and showed that smaller particles facilitated faster exchange. Grafting had a variable effect on the caesium/strontium cation uptake and release during absorption/desorption presumably as a result of the donors on grafted ligand interacting weakly with the large cations. Experiments using distilled water and synthetic liquor (carbonated sodium hydroxide), demonstrated uranium and plutonium species were extracted by all materials after grafting at concentrations in the SIXEP range. The most successful ligand/graft combination for plutonium at pH 7 was APTES grafted on clinoptilolite (10.79% carbon)

Experimental archeology and serious games: challenges of inhabiting virtual heritage

Experimental archaeology has long yielded valuable insights into the tools and techniques that featured in past peoples’ relationship with the material world around them. However, experimental archaeology has, hitherto, confined itself to rigid, empirical and quantitative questions. This paper applies principles of experimental archaeology and serious gaming tools in the reconstructions of a British Iron Age Roundhouse. The paper explains a number of experiments conducted to look for quantitative differences in movement in virtual vs material environments using both “virtual” studio reconstruction as well as material reconstruction. The data from these experiments was then analysed to look for differences in movement which could be attributed to artefacts and/or environments. The paper explains the structure of the experiments, how the data was generated, what theories may make sense of the data, what conclusions have been drawn and how serious gaming tools can support the creation of new experimental heritage environments

The JNCC terrestrial biodiversity surveillance schemes: an assessment of coverage

Biodiversity information is needed to provide a sound evidence base for decision-making, including operational needs, statutory reporting requirements and strategic needs. In this study we sought to assess aspects of coverage so as to identify gaps in taxonomic, thematic (habitat) and spatial coverage which might need to be addressed in future

A new framework of spatial targeting for single-species conservation planning

Context: Organisations acting to conserve and protect species across large spatial scales prioritise to optimise use of resources. Spatial conservation prioritization tools typically focus on identifying areas containing species groups of interest, with few tools used to identify the best areas for single-species conservation, in particular, to conserve currently widespread but declining species. / Objective: A single-species prioritization framework, based on temporal and spatial patterns of occupancy and abundance, was developed to spatially prioritize conservation action for widespread species by identifying smaller areas to work within to achieve predefined conservation objectives. / Methods: We demonstrate our approach for 29 widespread bird species in the UK, using breeding bird atlas data from two periods to define distribution, relative abundance and change in relative abundance. We selected occupied 10-km squares with abundance trends that matched species conservation objectives relating to maintaining or increasing population size or range, and then identified spatial clusters of squares for each objective using a Getis-Ord-Gi* or near neighbour analysis. / Results: For each species, the framework identified clusters of 20-km squares that enabled us to identify small areas in which species recovery action could be prioritized. / Conclusions: Our approach identified a proportion of species’ ranges to prioritize for species recovery. This approach is a relatively quick process that can be used to inform single-species conservation for any taxa if sufficiently fine-scale occupancy and abundance information is available for two or more time periods. This is a relatively simple first step for planning single-species focussed conservation to help optimise resource use

The risk of extinction for birds in Great Britain

t Over the last 20 years,species priorities for bird conservation in the UK have been guided by ‘Birds of Conservation Concern’ – an in-depth assessment made possible by the top-class data available on the status of the UK’s birds. For other wildlife, priorities tend to be informed by measures of extinction risk, generated by the IUCN Regional Red List process.We carried out the first formal IUCN assessment for birds in Great Britain. Of the 241 species assessed, 100 (43%) had at least one population (breeding and/or non-breeding) that qualified as Threatened using the standard IUCN Red List criteria and categories. Of 289 separate assessments of breeding or non-breeding populations, 39% qualified as Threatened (8% Critically Endangered, 14% Endangered, 17% Vulnerable) with a further 10% classified as Near Threatened. Both Golden Oriole Oriolus oriolus and Fieldfare Turdus pilaris were assessed as being Critically Endangered (Possibly Extinct) as breeding species, in addition to seven species that are already extinct (either Extinct or Regionally Extinct). The proportion of GB birds qualifying as Threatened was high compared with birds elsewhere in Europe and other taxonomic groups in GB. We believe that, if similar data were available, levels of extinction risk would be higher for other areas/taxa than is currently estimated

What do students find difficult when they read Shakespeare?:Problems and solution

Teaching and learning Shakespeare takes place across the world. Pedagogical matters have been the subject of much discussion in the last few decades. This article begins by reviewing that discussion, showing how different approaches – textual, contextual and active (or performance) – connect with the language of the plays. No study, it is pointed out, has conducted an empirical investigation as to what exactly students find problematic when they read the language of Shakespeare’s plays, an obvious first step, one might think, in designing an approach. The main aim of this article was to describe a study designed to do exactly this. It was conducted with two groups of Shakespeare students, one with English as a first language and one with English as an additional language. Participants were asked to identify difficulties in extracts from plays, rate specific linguistic forms according to difficulty and discuss what they think of Shakespeare’s language. Common areas of difficulty included archaic words, borrowings from other languages, coinages and false friends. With these findings in mind, the article briefly reflects on pedagogical solutions that are corpus-related, arguing that these address some of the problems associated with traditional textual approaches by requiring the active involvement of learners, treating language in a contextualised fashion and focussing on the language itself. © The Author(s) 2020

Diversity of response and effect traits provides complementary information about avian community dynamics linked to ecological function

Functional diversity metrics based on species traits are widely used to investigate ecosystem functioning. In theory, such metrics have different implications depending on whether they are calculated from traits mediating responses to environmental change (response traits) or those regulating function (effect traits), yet trait choice in diversity metrics is rarely scrutinized. Here, we compile effect and response traits for British bird species supplying two key ecological services—seed dispersal and insect predation—to assess the relationship between functional diversity and both mean and stability of community abundance over time. As predicted, functional diversity correlates with stability in community abundance of seed dispersers when calculated using response traits. However, we found a negative relationship between functional diversity and mean community abundance of seed dispersers when calculated using effect traits. Subsequently, when combining all traits together, we found inconsistent results with functional diversity correlating with reduced stability in insectivores, but greater stability in seed dispersers. Our findings suggest that trait choice should be considered more carefully when applying such metrics in ecosystem management