Interaction of Stern layer and domain structure on photochemistry of lead-zirconate-titanate.

Perovskite ferroelectric materials such as PZT have long been known to have wideband semiconducting properties. It has also been found that they have interesting spatially controllable surface photochemical effects that are not seen in 'normal' semiconductors. This has led to their being studied as possible tools in areas such as metal salt reduction and oxidation for nanoparticle growth. This paper discusses the effects of incident photon energy on the reduction of Ag0 onto PZT(30/70) surfaces with particular emphasis on the part played by energy band bending and the Stern layer. It was found that for increasing photon energy between 4.4 and 5.0 eV both the [1 1 1] and the [1 0 0] orientations of PZT followed a similar trend in that the average Ag0 cluster cross-sectional area increased by a ratio of ca 1.6 to 1. This increase was put down to the higher energy photons exciting more electrons from deeper in the density of states for the material allowing a greater reduction rate of Ag+ at the surface

Insights into the relationship between inherent materials properties of PZT and photochemistry for the development of nanostructured silver.

Recently there has been great interest in using patterned ferroelectric materials for the photochemical growth of metal nanostructures. Variations in surface and sub-surface structure influence the photochemical processes. Here we show that crystallography, and hence remnant polarization, of the ferroelectric affects photo-deposition. The ratio of metal growth on c– and c+ domains varies from 1 : 2 for [100] to 1 : 100 for [111]. This is shown to be dependent on the variations in the band structu

Problems encountered in buying woolens and worsteds for a retail textile store

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Touching Topography: Negotiating Landscape Encounters with ‘Several Parts’ of the Wye Valley Area of Outstanding Natural Beauty.

This collaborative research project explores the significance of the Wye Valley Area of Outstanding Natural Beauty as a meaningful site for contemporary society and especially for a small selection of artists who reside there, some of them, for over thirty years. The research has enquired as to the possible agency of the landscape in expressive media and the artist’s part as catalyst in the creative process. Over the last four hundred years, many representations of landscape in Western Europe, including those of the Wye Valley, have reduced human experience of topography to a vertical, flat and oblong plane. By being framed, drawings, prints and paintings have hedged in foliage, cordoned vistas and fenced off panoramas. Such depictions have arguably reduced a comprehensive, corporeally centred encounter to an ‘ocularcentric’ one. Subsequently, due to the continued nature of framing, photography, and more recently, smartphone photography has done little to dissolve the frame placed between us and the world we witness. Such photography repeatedly reinstates the visual values of others and continues to centre on the visual account of reality. A botanically abundant setting such as the Lower Wye Valley is arguably a sensorially stimulating site; a place within which to be near living (and dying) matter; investigations were therefore situated within the predominantly arboreal landscape along the Wye, roughly between Ross and Chepstow and through the implementation of a broad range of intentionally immersive research methodologies. By using auto-ethnography, observation, ambulatory interviews, researcher-led group walks and making pilotstudies, it was hoped that any resulting data would be informed by actual encounters with the material nature of the location. By adopting a physically centred approach to the study, it was the intention to elicit primary responses from participants as part of iv endorsing a more multi-modal approach to experiencing landscape with the intended result being a more ecologically and empathetic relationship with place

Techniques and applications of in-line holography

The analysis of aerosols was one of the first direct applications of holography and illustrates the advantage of in-line holography over photographic or direct observation methods. The diffracted light waves from an illuminated sample volume are made to interfere with a phase related reference wave and the resulting hologram can be used to produce a real, magnified, three-dimensional image of the original sample volume. It therefore provides a unique approach to the in-situ analysis of dynamic particle fields. However, although the technique has many important applications, its usefulness has been limited by the quality of the reconstructed image. The choice of recording materials and processing methods and their contribution to the image quality, has been investigated. This has resulted in improved images from both phase and absorption holograms. By direct analysis of the reconstructed image, the size, shape, orientation and velocity of individual droplets or particles is obtained. The technique has been used to determine the droplet size distribution from several agricultural spray devices and in this context has been compared to some of the major existing sizing systems. In addition, in-line holography has been applied to the study of droplet behaviour near cotton leaf surfaces. The effect of parameters such as droplet size and wind speed on the impaction efficiency was investigated to determine the optimum droplet size for specific spraying conditions. Finally, the technique has been applied to problems of concentration studies, the measurement of natural spore velocities and the conditions governing ligament formation from rotary atomisers

Quantifying the Offset of Greenhouse Gas Emissions at the University of North Alabama

This study quantified the discrete and areal carbon sequestration capacity of the University of North Alabama’s green infrastructure. USDA i-Tree was used to analyze and report on the carbon sequestration of 1487 campus trees, which provided -82.29 metric tons CO2 sequestration. Quantification of CO2 sequestered for 61 acres of undisturbed stands of native forest is -56.45 MT CO2. A summated sequestration capacity of UNA green infrastructure is estimated at -138.74 metric tons of CO2 per year. Sequestration capacity of the University of North Alabama’s green infrastructure is compared to their direct emissions for 2017. The scope I CO2e emissions from gasoline, diesel, and natural gas totaled 1,982.10 Metric tons. The offset capacity of UNA green infrastructure was estimated at 6.98% of UNA Scope I emissions, leaving a balance of 1,848.36 Metric tons of CO2e emission as UNA’s Scope I footprint

Feasibility of recruitment to an oral dysplasia trial in the United Kingdom

Background: Oral epithelial dysplasia (OED) has a malignant potential. Therapeutic options for OED remain both limited and without good evidence. Despite surgery being the most common method of treating OED, recurrence and potentially significant morbidity remain problematic. Consequently, there has been much interest in non-surgical treatments for OED. Cyclo-oxygenase (COX) up-regulation is known to occur in the dysplasia-carcinoma sequence and evidence now exists that COX-2 is a prognostic marker of malignant transformation in OED. COX-inhibitors are therefore considered a potential therapeutic strategy for treating this condition. We aimed to provide both proof of principal evidence supporting the effect of topical COX inhibition, and determine the feasibility of recruitment to an OED chemoprevention trial in the UK. Methods: Recruitment of 40 patients with oral leukoplakia to 4 study arms was planned. The total daily dose of Aspirin would increase in each group and be used in the period between initial diagnostic and follow-up biopsies. Results: During the 15-month recruitment period, 15/50 screened patients were eligible for recruitment, and 13 (87%) consented. Only 1 had OED diagnosed on biopsy. 16 patients were intolerant of, or already taking Aspirin and 16 patients required no biopsy. Initial recruitment was slow, as detection relied on clinicians identifying potentially eligible patients. Pre-screening new patient letters and directly contacting patients listed for biopsies improved screening of potentially eligible patients. However, as the incidence of OED was so low, it had little impact on trial recruitment. The trial was terminated, as recruitment was unlikely to be achieved in a single centre. Conclusion: This feasibility trial has demonstrated the low incidence of OED in the UK and the difficulties in conducting a study because of this. With an incidence of around 1.5/100,000/year and a high proportion of those patients already taking or intolerant of Aspirin, a large multi-centred trial would be required to fulfil the recruitment for this study. The ability of topical non-steroidal anti-inflammatory drugs to modify COX and prostaglandin expression remains an important but unanswered question. Collaboration with centres in other parts of the world with higher incidences of the disease may be required to ensure adequate recruitment. ISRCTN: 31503555