Deposition and characterisation of nickel oxide based coatings for advanced glazing applications

This thesis is a comparative study of nickel oxide based thin films for use as a counter electrode in a variable transmittance electrochromic device. Coatings have been prepared using anodic electrodeposition, colloidal precipitation and radio frequency (r.f.) sputtering. Systematic studies of the effect of deposition process parameters on optical and electrochromic properties of such films have been undertaken. Optimum conditions for the deposition of coatings deposited by colloidal and anodic deposition have been determined. A novel process for the colloidal deposition of electrochromic a-Ni(OH)2 coatings using a simple one dip process is reported. Also the electrochromic properties of coatings anodically deposited from aqueous solutions containing NiS04 and NH40H were improved by the addition of the non-ionic surfactant polyoxyethylene sorbitan monolaurate. Spectroscopic and electrochemical analytical techniques were used to identify the chemical composition of the coloured and bleached states. It was found using Fourier transform infra-red spectrophotometry (FTIR) that coatings deposited by anodic and colloidal deposition contained f3-Ni(OH)2 and a-Ni(OH)2 respectively in the as-deposited and transparent states. For coatings deposited by both techniques 13 or y-NiOOH was detected in the coloured state using FTIR. Using Raman spectroscopy, y-NiOOH was detected in the coloured state for coatings deposited by anodic deposition from solutions containing the additive polyoxyethylene sorbitan monolaurate. I3-Ni(OH)2 was also detected in the transparent state of r.f. sputtered coatings that were electrochemically cycled in 1M KOH(aq). Using cyclic voltammetry the oxidation of nickel hydroxide to the oxyhydroxide was detected during colouration for coatings produced using anodic electrodeposition, colloidal precipitation and r.f. sputtering (after cycling sputtered films for 1 hour in 1M KOH(aq). This information has been compared for films prepared using the different deposition techniques to enable the respective colouration mechanisms to be elucidated. Prototype electrochromic devices have been constructed and their performances assessed. It can be concluded that nickel oxide based coatings can be used as suitable counter electrodes for hydrated electrochromic devices

Generation of stress in the storage particles of lithium-ion batteries

Models are developed for the transport of lithium (Li) ions in the electrolyte of Li ion batteries, their diffusion through storage electrode particles, and their kinetics through the surface of the particles between the electrolyte and the particles. As a consequence of the Li ion intercalating in the storage particles, their lattice swells, leading to elastic stress when the concentration of Li ions in the particles is not uniform. The models of transport are based on standard concepts for multicomponent diffusion in liquids and solids, but are not restricted to dilute solutions, or to small changes in the concentration of the diffusing species. In addition, phase changes are permitted during mass transport as the concentration of Li varies from the almost depleted state of the storage particle to one where the material is saturated with its ions. The elastic swelling and shrinkage may involve very large dilatations, which can be allowed for in the formulation of the model. Thus, the models can be suitable for storage particle, where the amount of Li can vary by large amounts depending on the state of charge, for staging as observed in the storage process in graphite, for the enormous swelling that takes place when silicon is used for storage, and for electrolytes in which the concentration of Li ions is high. The model is used to compute the processes of charging and discharging the battery to assess the parameters that influence the development of stress in the storage particles, and to deduce the likelihood of fracture of the storage particle material. The objective is to assess designs of porous electrode microstructures that permit rapid charging and discharging, but obviate the likelihood of fracture and other mechanical damage that limit the performance and reliability of the battery

A break-even analysis of UK universities

working pape

A two-fold study of equine weaning practices and behaviours displayed following mare removal

The behavioural effects on the foal and dam during weaning in horses are well documented and it is commonly agreed that both are likely to suffer from stress at this time. Many different weaning methods are employed worldwide, with no indication of the least stress inducing. This study has two aims. First, to document frequency of weaning method, type of breeder, foal age at the time of mare removal and reason for use of weaning method. Second, to compare behaviours following abrupt and gradual weaning methods. The first aim was addressed by a questionnaire distributed globally via social media and equine academic societies’ distribution lists. All (100%) of the 440 responses were usable. Data were collated and statistically analysed. Gradual weaning was the most common (40.5%) method, and abrupt method second most common (30.9%). Typically, larger studs which breed more foals per annum, tend to wean earlier and use abrupt methods, smaller studs, breeding few foals per annum, tend to wean later using gradual or ‘other’ methods of weaning. The second aim was addressed via behavioural observation of two groups of seven foals, one group subjected to gradual weaning and the second to abrupt weaning. Foals displayed increased behaviour frequency post-mare removal versus pre-mare removal. Locomotary behaviours increased following mare removal and eating and lying down behaviours decreased. Foals in the abrupt group displayed significantly more behaviours, post-mare removal than the gradual group. These results indicate that industry practice reflects a wide range of weaning 5 methods utilised for many reasons. Additionally, foals were more stressed following mare removal and use of gradual methods, may improve welfare

Can tuition fees be justified? A break-even analysis of the financial statements of UK universities

working pape

Size distribution measurements of wildfire smoke-influences aerosol at Yosemite National Park

Dec 2004.Includes bibliographical references.Sponsored by National Park Service H2380040002 to 04-56

Influences on the fraction of hydrophobic and hydrophilic black carbon in the atmosphere

Black carbon (BC) is a short term climate forcer that directly warms the atmosphere, slows convection, and hinders quantification of the effect of greenhouse gases on climate change. The atmospheric lifetime of BC particles with respect to nucleation scavenging in clouds is controlled by their ability to serve as cloud condensation nuclei (CCN). To serve as CCN under typical conditions, hydrophobic BC particles must acquire hygroscopic coatings. However, the quantitative relationship between coatings and hygroscopic properties for ambient BC particles is not known nor is the time scale for hydrophobic-to-hydrophilic conversion. Here we introduce a method for measuring the hygroscopicity of externally and internally mixed BC particles by coupling a single particle soot photometer with a humidified tandem differential mobility analyzer. We test this technique using uncoated and coated laboratory generated model BC compounds and apply it to characterize the hygroscopicity distribution of ambient BC particles. From these data we derive that the observed number fraction of BC that is CCN active at 0.2% supersaturation is generally low in an urban area near sources and that it varies with the trajectory of the airmass. We anticipate that our method can be combined with measures of air parcel physical and photochemical age to provide the first quantitative estimates for characterizing hydrophobic-to-hydrophilic conversion rates in the atmosphere.Peer reviewe

Maori Responses to Covid-19

Mäori infection rates from Covid-19 are perhaps the only example in Aotearoa New Zealand’s contemporary history where Mäori have achieved better social outcomes than non-Mäori. This remarkable, and unanticipated, outcome is potentially a golden precedent for policymakers if we can determine the critical factors that reversed embedded trends of disproportionate disadvantage. This article argues that, while the national lockdown and science-based approach were important enablers of these outcomes, the nationwide Mäori response to Covid-19 should also be recognised as critical. It describes the key components of the Mäori response to Covid-19 and argues that, in composite, the Mäori response demonstrates the value and positive impact of ‘strengths-based’ policy at scale, as well as providing insight into key policy settings that would enable the positive outcomes in respect of Covid-19 to be replicated across other important policy areas

Fibrillar Elastomeric Micropatterns Create Tunable Adhesion Even to Rough Surfaces

Acknowledgements V.B., N.K.G., and E.A. contributed with conception and experimental design. V.B. performed the experiments. V.B., R.H., A.G., and R.M.M. carried out analysis and interpretation of data. V.B., R.H., A.G., and E.A. wrote the manuscript. V.B. and R.H. contributed equally to this work. V.B. acknowledges funding by SPP 1420 of the German Science Foundation DFG. E.A., N.K.G., and R.H. acknowledge funding from the European Research Council under the European Union/ERC Advanced Grant “Switch2Stick,” Agreement No. 340929.Peer reviewedPublisher PD