Simulations of Solid-on-Solid Models of Spreading of Viscous Droplets

We have studied the dynamics of spreading of viscous non-volatile fluids on surfaces by MC simulations of SOS models. We have concentrated on the complete wetting regime, with surface diffusion barriers neglected for simplicity. First, we have performed simulations for the standard SOS model. Formation of a single precursor layer, and a density profile with a spherical cap shaped center surrounded by Gaussian tails can be reproduced with this model. Dynamical layering (DL), however, only occurs with a very strongly attractive van der Waals type of substrate potential. To more realistically describe the spreading of viscous liquid droplets, we introduce a modified SOS model. In the new model, tendency for DL and the effect of the surface potential are in part embedded into the dynamics of the model. This allows a relatively simple description of the spreading under different conditions, with a temperature like parameter which strongly influences the droplet morphologies. Both rounded droplet shapes and DL can easily be reproduced with the model. Furthermore, the precursor width increases proportional to the square root of time, in accordance with experimental observations. PACS: 68.10.Gw, 05.70.Ln, 61.20.Ja.Comment: to appear in Physica A (1994), standard LaTex, 20 page

Zircon behaviour in low temperature environments

Abstract Zircon in mudstones, sandstones and greenschist facies metasediments has been investigated using conventional SEM techniques (BSE, CL and SE imaging) and reveals highly variable microstructures and textures. In these rocks, zircon readily responds to low temperature events due to radiation damage in its crystal lattice while crystalline zircon remains unmodified. Zircon that alters as a result of metamictization has a low BSE intensity (dark BSE zircon) and electron microprobe measurements show an enrichment of Mg, Al, Ca, Fe, Y and a loss of Si and Zr, while Hf appears to remain relatively constant between the unmodified parent and the resulting modified phase. Dark BSE zircon forms via two main mechanisms. The dominant dark BSE zircon form (Group 1) has a microstructure containing an abundance of pores, cavities and inclusions forming as a result of a coupled dissolution-reprecipitation mechanism. Electron backscattered diffraction (EBSD) analyses suggests that the structure is composed of randomly orientated nanocrystalline zircon. The other form of dark BSE zircon (Group 2) is produced by a solid-state diffusion-driven cation-exchange process in which structural recovery occurs (as determined by EBSD) and where inclusions or pores are absent in the microstructure of the product phase. The different forms of altered zircon are chemically indistinct. Zircon outgrowths (c.1µm thick) on the margins of detrital unmodified zircon in clay-rich sandstones indicate Zr was transported from altered grains. These zircons crystallised below 100°C. The upper temperature at which metamict zircon may be dissolved is constrained by the annealing temperature of the zircon lattice whereby metamict areas are repaired above c.250°C. Zircon outgrowths are larger (c.3µm thick) and in much greater abundance in slates that have experienced deformation and temperatures c.350°C. They have a complex microstructure, partly as a result of interactions with xenotime that also forms outgrowths upto 12µm thick on zircon. Xenotime inclusions and zircon-xenotime complexes have been identified within zircon outgrowths using TEM and LV-STEM. Electron transparent foils of the outgrowth were prepared using the FIB microscope. Zircon outgrowths have similar chemical characteristics to dark BSE zircon but have distinctly different substitution relationships. There are also differences between the chemistry of dark BSE zircon from sedimentary and greenschist facies rocks where the latter is considerably more enriched in Al, Y and Ca. The implications of this are that zircon chemistry is strongly influenced by the local conditions in which in formed. Sedimentary processing causes considerable bias in the zircon population. Fine-grained sediment is a sink for high U and Th, heavily radiation damaged, old zircon in comparison to mature sediment that is likely to contain an abundance of low U and Th zircon or young zircon upon deposition. Small metamict zircon fragments are prone to dissolution and can be readily stripped from the matrix of fine-grained sediments. The concentration of zircon outgrowths in fine-grained sedimentary and metasedimentary rocks is primarily the result of sedimentological processes. The findings of this work illustrate the importance of studying minerals in-situ and within their petrological context. The wide-spread and abundant nature of low temperature zircon is a major consideration for geochronology, sedimentary provenance studies, the interpretation of zoning in zircon and has significant implications for the long-term storage of radioactive material

Tracing Hyperobjects: Digital Deep Mapping in the Anthropocene

Agency in the Anthropocene is premised on knowledge of a situation which challenges human comprehension through its complexity and exceeds the spatio-temporal limits of individual, human-scale experience. It hints at a scale and entanglement of factors that likewise defy conventional mapping and spatial methods. Timothy Morton offers the hyperobject as a description of such objects, and proposed new speculative and phenomenological strategies for their exploration. This raises a complex and daunting question: how can challenges of perceiving–and mapping–the forces at work at more-than-human scale be effectively addressed? In this paper, we propose a digitally-expanded notion of ‘Deep Mapping’ as a potential methodology for sensing the contours of the hyperobject: a tracing or palpation of objects of knowledge which exceed the individual. In previous cultural moments, strategies such as Fredric Jameson’s ‘cognitive mapping’ have offered pathways for agency through spatial exploration and ordering of complex situations, though often at the expense of temporality. Deep mapping, conversely, temporalises the act of mapping through narrativisation, but is typically localised and deliberately limited in scale. We argue that the use of digital strategies to augment the deep map can transcend individual and local experience, and provides access to an understanding of the object by opening cognition to its many hidden dimensions, at spatial and temporal scales both above and below those available to human perception. If narrative can be used to reveal the psychological and cultural depths hidden in geographical space, then digital methods such as GIS and data visualisation can be used to demonstrate the way these depths are themselves part of higher-order temporal and spatial patterns. By combining the two, it is possible to ameliorate the deficiencies of other approaches to mapping the multiplicity of agencies at play in environmental perception while simultaneously accepting the finitude of knowledge possible of a hyperobject

Concurrent Sessions D: Downstream Migrant Surface Collectors-What Works and What Doesn\u27t Work - Evaluation of the Hydraulic Performance of a Free Surface Fish Bypass

In 2004, following consultations with the Federal Energy Regulatory Commission (FERC), the National Marine Fisheries Service (NOAA Fisheries) issued a document that included a Biological Opinion relevant to Priest Rapids Dam. A subsequent Biological Opinion, issued by NOAA Fisheries in 2008, was incorporated with the new FERC license. The 2008 Biological Opinion contained the same requirements as the 2004 Biological Opinion with respect to the survival objectives for downstream migrating juvenile fish. These objectives are 93% survival of juveniles and a juvenile and adult combined survival of 91% for the species listed for protection. Grant PUD is seeking to achieve at least 95% juvenile survival past the Priest Rapids Dam. In the past, Grant PUD spilled roughly 61% of the total river flow at Priest Rapids Dam during the spring fish passage season with the aim of achieving the survival target. A study was undertaken to identify a number of different fish passage alternatives for Priest Rapids Dam including: screening systems, collecting and bypassing fish through surface-oriented openings, and/or through modified turbine passages. The study suggested several options that had the potential to provide high fish passage efficiency and survival in a more efficient manner than high-volume spill programs. Further work concentrated on fish bypass through surface releases with prototype tests being conducted to assess the efficiency of fish collection as a function of bypass flow. Physical and numerical modeling were also undertaken to support the design of surface bypass alternatives. The final bypass design consisted in a modified spillway with elevated ogee crest in bays 20, 21 and 22.This paper presents results of the reduced scaled laboratory and CFD models developed to evaluate different bypass conceptual designs. Two numerical models were used; the commercial code Fluent and the open source code Open Foam. Details of model development and validation with data obtained in the reduced scale laboratory model will be presented. Possible cavitation, loads and impact on the tailrace with the selected bypass were computed and will be discussed

A dynamic topography for visualizing time and space in fictional literary texts

This paper presents research on creating interactive prototypes for visualizing temporal spatial relationships in fictional literary texts. Developed within the context of the Chronotopic Cartographies project, a practice-led inquiry yielded dynamic visualizations from literary texts, the research explores the development and application of interactive three-dimensional environments illustrating the ‘chronotopic’, time-space relationships across a series of fictional literary texts. Expert feedback highlights the potential of the interaction model as a useful visual paradigm for supporting methods of reflective inquiry hypothesis making. The work also represents a potential model for creating interactive temporal visualizations which support hypothesis making across a broader sphere of the humanities

Mapping British Public Monuments related to Slavery

This article is a product of the first complete survey of British public representational monuments in the UK related to transatlantic slavery, available online at Britishpublicmonumentsrelatedtoslavery.net. Identifying over 900 monuments, it brings this survey to bear on current public and policy debates about such monuments’ history, significance and meaning vis-à-vis slavery, art and heritage. Examining the monuments at scale, we identify the monuments’ patterns of production and provide data-led answers to specific questions such as what Britain’s most significant monumental legacies of slavery are; how enslaved people appear in British public monuments; and how this data might support rethinking these monuments

Global, regional, and national disability-adjusted life-years (DALYs) for 333 diseases and injuries and healthy life expectancy (HALE) for 195 countries and territories, 1990-2016 : a systematic analysis for the Global Burden of Disease Study 2016

Background Measurement of changes in health across locations is useful to compare and contrast changing epidemiological patterns against health system performance and identify specific needs for resource allocation in research, policy development, and programme decision making. Using the Global Burden of Diseases, Injuries, and Risk Factors Study 2016, we drew from two widely used summary measures to monitor such changes in population health: disability-adjusted life-years (DALYs) and healthy life expectancy (HALE). We used these measures to track trends and benchmark progress compared with expected trends on the basis of the Socio-demographic Index (SDI). Interpretation At a global level, DALYs and HALE continue to show improvements. At the same time, we observe that many populations are facing growing functional health loss. Rising SDI was associated with increases in cumulative years of life lived with disability and decreases in CMNN DALYs offset by increased NCD DALYs. Relative compression of morbidity highlights the importance of continued health interventions, which has changed in most locations in pace with the gross domestic product per person, education, and family planning. The analysis of DALYs and HALE and their relationship to SDI represents a robust framework with which to benchmark location-specific health performance. Country-specific drivers of disease burden, particularly for causes with higher-than-expected DALYs, should inform health policies, health system improvement initiatives, targeted prevention efforts, and development assistance for health, including financial and research investments for all countries, regardless of their level of sociodemographic development. The presence of countries that substantially outperform others suggests the need for increased scrutiny for proven examples of best practices, which can help to extend gains, whereas the presence of underperforming countries suggests the need for devotion of extra attention to health systems that need more robust support

A post-glacial sea level hinge on the central Pacific coast of Canada

Post-glacial sea level dynamics during the last 15,000 calendar years are highly variable along the Pacific coast of Canada. During the Last Glacial Maximum, the Earth\u27s crust was depressed by ice loading along the mainland inner coast and relative sea levels were as much as 200 m higher than today. In contrast, some outer coastal areas experienced a glacial forebulge (uplift) effect that caused relative sea levels to drop to as much as 150 m below present levels. Between these inner and outer coasts, we hypothesize that there would have been an area where sea level remained relatively stable, despite regional and global trends in sea level change. To address this hypothesis, we use pond basin coring, diatom analysis, archaeological site testing, sedimentary exposure sampling, and radiocarbon dating to construct sea level histories for the Hakai Passage region. Our data include 106 newly reported radiocarbon ages from key coastal sites that together support the thesis that this area has experienced a relatively stable sea level over the last 15,000 calendar years. These findings are significant in that they indicate a relatively stable coastal environment amenable to long-term human occupation and settlement of the area. Our results will help inform future archaeological investigations in the region