Probing the link between residual entropy and viscosity of molecular fluids and model potentials

This work investigates the link between residual entropy and viscosity based on wide-ranging, highly accurate experimental and simulation data. This link was originally postulated by Rosenfeld in 1977, and it is shown that this scaling results in an approximately monovariate relationship between residual entropy and reduced viscosity for a wide range of molecular fluids (argon, methane, CO2, SF6, refrigerant R-134a (1,1,1,2-tetrafluoroethane), refrigerant R-125 (pentafluoroethane), methanol, and water), and a range of model potentials (hard sphere, inverse power, Lennard-Jones, and Weeks-Chandler-Andersen). While the proposed "universal" correlation of Rosenfeld is shown to be far from universal, when used with the appropriate density scaling for molecular fluids, the viscosity of non-associating molecular fluids can be mapped onto the model potentials. This mapping results in a length scale that is proportional to the cube root of experimentally measureable liquid volume values

Fossil trees, tree moulds and tree casts in the Palaeocene Mull Lava Field, NW Scotland: context, formation and implications for lava emplacement

Megafossils and macrofossils of terrestrial plants (trees, leaves, fruiting bodies, etc.) are found in sedimentary and pyroclastic units interbedded with lavas in many ancient lava fields worldwide, attesting to subaerial environments of eruption and the establishment of viable plant communities during periods of volcanic quiescence. Preservation within lava is relatively rare and generally confined to the more robust woody tissues of trees, which are then revealed in the form of charcoal, mineralised tissue or as trace fossil moulds (tree moulds) and casts of igneous rock (tree casts, s.s.). In this contribution, we document several such fossil trees (s.l.), and the lavas with which they are associated, from the Palaeocene Mull Lava Field (MLF) on the Isle of Mull, NW Scotland. We present the first detailed geological account of a unique site within the Mull Plateau Lava Formation (MPLF) at Quinish in the north of the island and provide an appraisal of the famous upright fossil tree – MacCulloch's Tree – remotely located on the Ardmeanach Peninsula on the west coast of the island, and another large upright tree (the Carsaig Tree) near Malcolm's Point in the district of Brolass, SW Mull; both occurring within the earlier Staffa Lava Formation (SLF). The taphonomy of these megafossils, along with palynological and lithofacies assessments of associated strata, allows speculation of likely taxonomic affinity and the duration of hiatuses supporting the establishment of forest/woodland communities. The Ardmeanach and Carsaig specimens, because of their size and preservation as upright (? in situ) casts enveloped by spectacularly columnar-jointed basaltic lava, appear to be unique. The aspect of these trees, the thickness of the enveloping lavas and the arrangement of cooling joints adjacent to the trees, implies rapid emplacement, ponding and slow, static cooling of voluminous and highly fluid basaltic magma. The specimens from Quinish include two prostrate casts and several prostrate moulds that collectively have a preferred orientation, aligning approximately perpendicular to that of the regional Mull Dyke Swarm, the putative fissure source of the lavas, suggesting local palaeo-flow was directed towards the WSW. The Quinish Lava is an excellent example of a classic pāhoehoe (compound-braided) type, preserving some of the best examples of surface and internal features so far noted from the Hebridean Igneous Province (HIP) lava fields. These Mull megafossils are some of the oldest recorded examples, remarkably well preserved, and form a significant feature of the island's geotourism industry

The Return of Business Creation

Freshly released government data show that new business formation rebounded in 2011, after four years of decline, from the depths of the Great Recession. This is a welcome development -- new businesses are the engine of job creation in the United States economy and an important source of innovation and productivity. Perhaps most importantly, the rise in new business formation between 2010 and 2011 was geographically dispersed throughout the United States.While the rise of new business creation in 2011 is a significant development -- it is the first annual gain in five years and the largest percentage annual increase in nearly a decade -- the bulk of this paper examines two classes of new businesses that most closely resemble entrepreneurship: companies less than one year old with one to four employees and those with fine to nine. This analysis finds that the smallest of these new firms represent most of the increase in firm formation in 2011:* New companies with one to four employees comprise the vast majority of new businesses formed each year, accounting for, on average, 86 percent of new firms since the late 1970s in the BDS data. * Job creation at new businesses of all sizes increased by 4.3 percent, and rose by 5.4 percent in new companies with one to four employees, reversing four consecutive years of decline for those smallest companies. * Companies less than one year old with one tofour employees have created, on average, more than 1 million jobs per year over the past three decades; those with five to nine employees have added, on average, half a million jobs per year. * With a promise of more detailed analysis infuture reports, this paper presents maps that illustrate the increased share of new business formation in most states and metro areas across the nation

Measuring, Predicting and Visualizing Short-Term Change in Word Representation and Usage in VKontakte Social Network

Language in social media is extremely dynamic: new words emerge, trend and disappear, while the meaning of existing words can fluctuate over time. Such dynamics are especially notable during a period of crisis. This work addresses several important tasks of measuring, visualizing and predicting short term text representation shift, i.e. the change in a word's contextual semantics, and contrasting such shift with surface level word dynamics, or concept drift, observed in social media streams. Unlike previous approaches on learning word representations from text, we study the relationship between short-term concept drift and representation shift on a large social media corpus - VKontakte posts in Russian collected during the Russia-Ukraine crisis in 2014-2015. Our novel contributions include quantitative and qualitative approaches to (1) measure short-term representation shift and contrast it with surface level concept drift; (2) build predictive models to forecast short-term shifts in meaning from previous meaning as well as from concept drift; and (3) visualize short-term representation shift for example keywords to demonstrate the practical use of our approach to discover and track meaning of newly emerging terms in social media. We show that short-term representation shift can be accurately predicted up to several weeks in advance. Our unique approach to modeling and visualizing word representation shifts in social media can be used to explore and characterize specific aspects of the streaming corpus during crisis events and potentially improve other downstream classification tasks including real-time event detection

Chebyshev Expansions Empower Faster and More Precise Pure Fluid Calculations

Computationally efficient simulation of thermal systems is usually limited by evaluation of thermophysical properties. It is common (for instance in heat exchanger simulation) that more than 90% of the total runtime may be spent evaluating thermophysical properties. A key (and computationally expensive, especially for mixtures) part of that calculation is the determination of phase equilibrium. This work demonstrates that the use of Chebyshev expansions combined with extended precision calculations allows for a non-iterative numerical formulation that is more accurate than the iterative calculations with the full equation of state and is also much faster to evaluate. In essence, this approach makes phase equilibrium calculations of pure fluids from equations of state obsolete

Defoe, realism and the picaresque novel

This thesis deals with the continuing critical discussion of Defoe's fiction, and seeks the most appropriate ways of assessing his achievement. It is apparent that no general agreement has been reached about Defoe's work, and this arises from the way critics have sought for a kind of consistency throughout his work which is not to be found. The terms 'realism' and 'picaresque' are very frequently applied to Defoe's fiction, as all-encompassing critical terms. Each of these is examined, and defined ostensively. When applied to the novels, they are found to be useful in revealing Crusoe's jeopardy, Moll's innocence, and the problems of the ending of Roxana. However, such general critical terms obscure the development within Defoe's fiction, from the thematic confusion of Crusoe to the more integrated and organised Roxana. The final aim of this study is to draw attention to the neglected features of Crusoe, Moll, and Roxana, and to re-appraise both Defoe's achievement and the various ways of describing that achievement

Production of resonant particles in pion-deuteron interactions at 4 GeV/c

From a 400K picture sample of an exposure of 4 GeV/c π(^+) mesons in deuterium, the two channels π(^+)d → P(_s)Pπ(^+)π(^-) and π(^+)d → dπ(^+)π(^+)π(^-) are examined both by mass cut techniques and by a statistical cluster searching technique in the full 3n-5 dimensional kinematic space defined by the number of final state particles (n). The clustering technique is shown to reproduce the distributions found by mass cut methods with some sharpening of the angular distributions and an increase in the statistics of the resunance signular available for analysis. The method is tested by applying it to a Monte Carlo simulated experiment and the results are shown to give a high degree of seperation of the various sub-channels. The reaction π(^+)d → p(_s)pπ(^+)π(^-), with a cross-section of 2.10 ± 0.17 mb, is seen tobe dominated by the production of the pº and fº mesons. The regions of the pº and fº mesons are examined, and their spin structures determined by density matrix element analyses. These show that at low t values there are substantial S and S+P wave components under the pº and fº respectively. The pº meson data are shown to be compatible with >90% pure pion exchange at low values of t. For the coherent reaction π+d →dπ(^+)π(^-), which is dominated by pº production and the d* effect, the cross section is seen to be 0.316 ± 0.025 mb. The d* effect is shown to be compatible with the production of an intermediate Δ state, the subsecuent decay of which leaves an intact deuteron in the final state