Metal fluorides, metal chlorides and halogenated metal oxides as Lewis acidic heterogeneous catalysts. Providing some context for nanostructured metal fluorides

Aspects of the chemistry of selected metal fluorides, which are pertinent to their real or potential use as Lewis acidic, heterogeneous catalysts, are reviewed. Particular attention is paid to β-aluminum trifluoride, aluminum chlorofluoride and aluminas γ and η, whose surfaces become partially fluorinated or chlorinated, through pre-treatment with halogenating reagents or during a catalytic reaction. In these cases, direct comparisons with nanostructured metal fluorides are possible. In the second part of the review, attention is directed to iron(III) and copper(II) metal chlorides, whose Lewis acidity and potential redox function have had important catalytic implications in large-scale chlorohydrocarbons chemistry. Recent work, which highlights the complexity of reactions that can occur in the presence of supported copper(II) chloride as an oxychlorination catalyst, is featured. Although direct comparisons with nanostructured fluorides are not currently possible, the work could be relevant to possible future catalytic developments in nanostructured materials

An analytical connection between temporal and spatio-temporal growth rates in linear stability analysis

We derive an exact formula for the complex frequency in spatio-temporal stability analysis that is valid for arbitrary complex wave numbers. The usefulness of the formula lies in the fact that it depends only on purely temporal quantities, which are easily calculated. We apply the formula to two model dispersion relations: the linearized complex Ginzburg--Landau equation, and a model of wake instability. In the first case, a quadratic truncation of the exact formula applies; in the second, the same quadratic truncation yields an estimate of the parameter values at which the transition to absolute instability occurs; the error in the estimate decreases upon increasing the order of the truncation. We outline ways in which the formula can be used to characterize stability results obtained from purely numerical calculations, and point to a further application in global stability analyses.Comment: 36 pages, 16 figures; Article has been tweaked and reduced in size but essential features remain the same; Supplementary material (16 pages) is also include

Absolute linear instability in laminar and turbulent gas/liquid two-layer channel flow

We study two-phase stratified flow where the bottom layer is a thin laminar liquid and the upper layer is a fully-developed gas flow. The gas flow can be laminar or turbulent. To determine the boundary between convective and absolute instability, we use Orr--Sommerfeld stability theory, and a combination of linear modal analysis and ray analysis. For turbulent gas flow, and for the density ratio r=1000, we find large regions of parameter space that produce absolute instability. These parameter regimes involve viscosity ratios of direct relevance to oil/gas flows. If, instead, the gas layer is laminar, absolute instability persists for the density ratio r=1000, although the convective/absolute stability boundary occurs at a viscosity ratio that is an order of magnitude smaller than in the turbulent case. Two further unstable temporal modes exist in both the laminar and the turbulent cases, one of which can exclude absolute instability. We compare our results with an experimentally-determined flow-regime map, and discuss the potential application of the present method to non-linear analyses.Comment: 33 pages, 20 figure

Charting Complex Changes: Application of the eHealth Implementation Toolkit (e-HIT) in the Delivering Assisted Living Lifestyles at Scale (dallas) Programme

The 'dallas' (Delivering Assisted Living Lifestyles at Scale) programme is a UK-wide digital healthcare initiative that has been designed to support independent living, enhance preventative care, and improve lifestyles by harnessing the potential of e-health technologies and digital services. This short paper presents a brief update on one strand of the University of Glasgow evaluation of the dallas programme. We have used the e-Health Implementation Toolkit (e-HIT) to investigate processes involved in the implementation of e-health tools and digital services being developed and deployed across the dallas communities and to assess 'distance travelled' by communities from baseline to midpoint of a three year programme. Qualitative data analysis was guided by the Normalisation Process Theory (NPT) and Framework Analysis. The e-HIT scores indicated that the dallas communities had underestimated the amount of work involved in implementing at scale. Qualitative data analysis showed that communities have successfully navigated barriers in order to make significant progress in strategic areas, including the development of new models of partnership working resulting in brand recognition and agile service design. The dallas communities are now sharing lessons learned and generating new professional knowledge, skills and understanding across several key strategic areas required for operationalising the implementation of e-health technologies and digital services at scale. The new knowledge being generated through the dallas programme will contribute to the ongoing transformation of digitally enabled healthcare based on more personalised flexible models of provision which resonates with the current e-health policy environment

La réponse de Régis à Huet concernant le doute cartésien

La critique du cartésianisme formulée par Pierre-Daniel Huet à la fin du XVIIe siècle constitue l’un des événements les plus marquants de l’histoire du scepticisme à la période moderne. Cette critique se fonde sur l’arsenal des arguments sceptiques produits durant tout le XVIIe siècle et pave la voie à la position anti-métaphysique des Lumières, qui commence avec Bayle et se poursuit avec les philosophes en passant par Hume. La réponse attendue des cartésiens à l’encontre de Huet est venue de Pierre-Sylvain Régis, auquel Huet va répondre à son tour à plusieurs reprises. Bien que la critique de Huet ait porté sur l’ensemble des thèmes spécifiques au cartésianisme (le doute méthodique, le cogito, la clarté et la distinction des perceptions, etc.), et bien que Régis ait répondu sur tous ces points, il n’en reste pas moins que le débat entre eux s’est essentiellement concentré sur le doute cartésien, que nous examinons minutieusement ici à la lumière de leur confrontation.The attack of Pierre-Daniel Huet on Cartesianism at the end of the seventeenth century was one of the most significant events in the history of skepticism in the early modern period. It capitalized on the building momentum generated by the use of skeptical arguments throughout the century, and it opened the way to the anti-metaphysical stance of the Enlightenment, beginning with Bayle and passing to the philosophes, including Hume. The inevitable Cartesian response to Huet came from Pierre-Sylvain Regis, to whom Huet then responded in various ways. Although Huet’s attack had taken aim at all the themes with which Cartesianism has come to be associated (the method of doubt, the cogito, clarity and distinctness of perception, etc.), and although Regis replied on all these topics, the debate between them concentrated on Cartesian doubt, here closely examined in light of their debate

Quantum Backflow States from Eigenstates of the Regularized Current Operator

We present an exhaustive class of states with quantum backflow -- the phenomenon in which a state consisting entirely of positive momenta may have negative current and the probability flows in the opposite direction to the momentum. They are characterized by a general function of momenta subject to very weak conditions. Such a family of states is of interest in the light of a recent experimental proposal to measure backflow. We find one particularly simple state which has surprisingly large backflow -- about 41 percent of the lower bound on flux derived by Bracken and Melloy. We study the eigenstates of a regularized current operator and we show how some of these states, in a certain limit, lead to our class of backflow states. This limit also clarifies the correspondence between the spectrum of the regularized current operator, which has just two non-zero eigenvalues in our chosen regularization, and the usual current operator.Comment: 16 pages, 2 figure

Conceptualizing Constituent Perceptions of Success towards Public Education

The aggressive age of assessment and accountability to which the American public school system belongs, belies the dichotomy, or disparate and passionate views of how to appropriately determine growth or success of learning for our students. The differences are startling; polar opposites of conception and ideal, and controversial, with educational professionals at odds with policy makers and the general public. At issue, or the core of this debate, is the question of what is the most effective way in assessing our schools and the children within them? Is there really one way to assess or determine success and are we really being honest with ourselves when we say our students are learning and achieving

Conceptualizing Constituent Perceptions of Success towards Public Education

The aggressive age of assessment and accountability to which the American public school system belongs, belies the dichotomy, or disparate and passionate views of how to appropriately determine growth or success of learning for our students. The differences are startling; polar opposites of conception and ideal, and controversial, with educational professionals at odds with policy makers and the general public. At issue, or the core of this debate, is the question of what is the most effective way in assessing our schools and the children within them? Is there really one way to assess or determine success and are we really being honest with ourselves when we say our students are learning and achieving