Evaporation of Concentrated Polymer Solutions is Insensitive to Relative Humidity

A recent theory suggests that the evaporation kinetics of macromolecular solutions is insensitive to the ambient relative humidity (RH) due to the formation of a ‘polarisation layer’ of solutes at the air-solution interface. We confirm this insensitivity up to RH ≈ 80% in the evaporation of polyvinylalcohol solutions from open-ended capillaries. To explain the observed drop in evaporation rate at higher RH, we need to invoke compressive stresses due to interfacial polymer gelation. Moreover, RH-insensitive evaporation sets in earlier than theory predicts, suggesting a further role for a gelled ‘skin’. We discuss the relevance of these observations for respiratory virus transmission via aerosols

The evaporation of concentrated polymer solutions is insensitive to relative humidity

A recent theory suggests that the evaporation kinetics of macromolecular solutions is insensitive to the ambient relative humidity (RH) due to the formation of a `polarisation layer' of solutes at the air-solution interface. We confirm this insensitivity up to RH~80% in the evaporation of polyvinyl alcohol solutions from open-ended capillaries. To explain the observed drop in evaporation rate at higher RH, we need to invoke compressive stresses due to interfacial polymer gelation. Moreover, RH-insensitive evaporation sets in earlier than theory predicts, suggesting a further role for a gelled `skin'. We discuss the relevance of these observations for respiratory virus transmission via aerosols.Comment: Accepted in PR

Diffusive evaporation dynamics in polymer solutions is ubiquitous

Recent theory and experiments have shown how the buildup of a high-concentration polymer layer at a one-dimensional solvent-air interface can lead to an evaporation rate that scales with time as $t^{-1/2}$ and that is insensitive to the ambient humidity. Using phase field modelling we show that this scaling law constitutes a naturally emerging robust regime, Diffusion-Limited Evaporation (DLE). This regime dominates the dynamical state diagram of the system, which also contains regions of constant and arrested evaporation, confirming and extending understanding of recent experimental observations and theoretical predictions. We provide a theoretical argument to show that the scaling observed in the DLE regime occurs for a wide range of parameters, and our simulations predict that it can occur in two-dimensional geometries as well. Finally, we discuss possible extensions to more complex systems.Comment: 6 pages, 4 figure

Healthcare choice: Discourses, perceptions, experiences and practices

Policy discourse shaped by neoliberal ideology, with its emphasis on marketisation and competition, has highlighted the importance of choice in the context of healthcare and health systems globally. Yet, evidence about how so-called consumers perceive and experience healthcare choice is in short supply and limited to specific healthcare systems, primarily in the Global North. This special issue aims to explore how choice is perceived and utilised in the context of different systems of healthcare throughout the world, where choice, at least in policy and organisational terms, has been embedded for some time. The articles are divided into those emphasising: embodiment and the meaning of choice; social processes associated with choice; the uncertainties, risks and trust involved in making choices; and issues of access and inequality associated with enacting choice. These sociological studies reveal complexities not always captured in policy discourse and suggest that the commodification of healthcare is particularly problematic

Sparrows can't sing : East End kith and kinship in the 1960s

Sparrows Can’t Sing (1963) was the only feature film directed by the late and much lamented Joan Littlewood. Set and filmed in the East End, where she worked for many years, the film deserves more attention than it has hitherto received. Littlewood’s career spanned documentary (radio recordings made with Ewan MacColl in the North of England in the 1930s) to directing for the stage and the running of the Theatre Royal in London’s Stratford East, often selecting material which aroused memories in local audiences (Leach 2006: 142). Many of the actors trained in her Theatre Workshop subsequently became better known for their appearances on film and television. Littlewood herself directed hardly any material for the screen: Sparrows Can’t Sing and a 1964 series of television commercials for the British Egg Marketing Board, starring Theatre Workshop’s Avis Bunnage, were rare excursions into an area of practice which she found constraining and unamenable (Gable 1980: 32). The hybridity and singularity of Littlewood’s feature may answer, in some degree, for its subsequent neglect. However, Sparrows Can’t Sing makes a significant contribution to a group of films made in Britain in the 1960s which comment generally on changes in the urban and social fabric. It is especially worthy of consideration, I shall argue, for the use which Littlewood made of a particular community’s attitudes – sentimental and critical – to such changes and for its amalgamation of an attachment to documentary techniques (recording an aural landscape on location) with a preference for nonnaturalistic delivery in performance

CO adsorption on neutral iridium clusters

The adsorption of carbon monoxide on neutral iridium clusters in the size range of n = 3 to 21 atoms is investigated with infrared multiple photon dissociation spectroscopy. For each cluster size only a single v(CO) band is present with frequencies in the range between 1962 cm-1 (n = 8) and 1985 cm-1 (n = 18) which can be attributed to an atop binding geometry. This behaviour is compared to the CO binding geometries on clusters of other group 9 and 10 transition metals as well as to that on extended surfaces. The preference of Ir for atop binding is rationalized by relativistic effects on the electronic structure of the later 5d metals

Open access and open source in chemistry

Scientific data are being generated and shared at ever-increasing rates. Two new mechanisms for doing this have developed: open access publishing and open source research. We discuss both, with recent examples, highlighting the differences between the two, and the strengths of both

Conditional citizens? welfare rights and responsibilities in the late 1990s

In Britain the relationship between welfare rights and responsibilities has undergone change. A new welfare 'consensus' that emphasizes a citizen ship centred on notions of duty rather than rights has been built. This has allowed the state to reduce its role as a provider of welfare and also defend a position in which the welfare rights of some citizens are increas ingly conditional on those individuals meeting compulsory responsibili ties or duties. This concentration on individual responsibility/duty has undermined the welfare rights of some of the poorest members of society. Three levels of debate are considered within the article: academic, pol itical and 'grassroots'. The latter is included in an attempt to allow some 'bottom up' views into what is largely a debate dominated by social sci entists and politicians

Why Social Enterprises Are Asking to Be Multi-stakeholder and Deliberative: An Explanation around the Costs of Exclusion.

The study of multi-stakeholdership (and multi-stakeholder social enterprises in particular) is only at the start. Entrepreneurial choices which have emerged spontaneously, as well as the first legal frameworks approved in this direction, lack an adequate theoretical support. The debate itself is underdeveloped, as the existing understanding of organisations and their aims resist an inclusive, public interest view of enterprise. Our contribution aims at enriching the thin theoretical reflections on multi-stakeholdership, in a context where they are already established, i.e. that of social and personal services. The aim is to provide an economic justification on why the governance structure and decision-making praxis of the firm needs to account for multiple stakeholders. In particular with our analysis we want: a) to consider production and the role of firms in the context of the “public interest” which may or may not coincide with the non-profit objective; b) to ground the explanation of firm governance and processes upon the nature of production and the interconnections between demand and supply side; c) to explain that the costs associated with multi-stakeholder governance and deliberation in decision-making can increase internal efficiency and be “productive” since they lower internal costs and utilise resources that otherwise would go astray. The key insight of this work is that, differently from major interpretations, property costs should be compared with a more comprehensive range of costs, such as the social costs that emerge when the supply of social and personal services is insufficient or when the identification of aims and means is not shared amongst stakeholders. Our model highlights that when social costs derived from exclusion are high, even an enterprise with costly decisional processes, such as the multistakeholder, can be the most efficient solution amongst other possible alternatives