300 research outputs found

    A linear domain decomposition method for two-phase flow in porous media

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    This article is a follow up of our submitted paper [11] in which a decomposition of the Richards equation along two soil layers was discussed. A decomposed problem was formulated and a decoupling and linearisation technique was presented to solve the problem in each time step in a fixed point type iteration. This article extends these ideas to the case of two-phase in porous media and the convergence of the proposed domain decomposition method is rigorously shown.Comment: 8 page

    The Rossborough Inn on the Campus of the University of Maryland

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    Study undertaken by graduate students of the Historic Preservation Program, School of Architecture, Planning and Preservation, University of Maryland, College Park. January 2017. Dennis J. Pogue, faculty advisor; Donald J. Linebaugh, program director.This study of the Rossborough Inn was undertaken by graduate students in the University of Maryland Historic Preservation Program under the aegis of the university’s Office of Facilities Management. The goal of the project has been to trace the history and determine the significance of the Rossborough Inn and to use those findings in critically assessing options for its future role in the evolving campus. Each of three major campus projects that are currently in the planning stages have the potential to dramatically impact the Rossborough Inn and Gardens, either as significant threats to the integrity of the site or as exciting opportunities to return the historic structure to its earlier prominence. The proposed Purple Line light rail system is slated to be built directly north of the Rossborough Inn, with a stop positioned nearby. The Discovery District redevelopment scheme is envisioned as transforming the character of the Route 1 corridor, to include erecting a satellite museum of the Phillips Art Gallery. The potential sites for the new building for the School of Public Policy are located directly south and/or west of the Rossborough Inn. From circa 1803, when a local entrepreneur named Richard Ross constructed the Rossborough Inn, the building hosted a variety of influential leaders of the day. By the 1830s the Rossborough Inn had been converted as a private residence on the “Rossburg” tenant farm; in 1858 it was sold by the Calvert family to the newly established Maryland Agricultural College. Over the next three decades the building was pressed into a variety of uses: as a residential rental property, then as the residence for the college president, and finally as the college laundry. When the Hatch Act was passed by Congress in 1887, the Rossborough Inn was selected to be the home for the Maryland State Agricultural Experiment Station. After serving in that capacity for almost 50 years, in 1938-39 the vacant structure was restored under the direction of the Works Progress Administration. The Rossborough Inn operated as a tea room and house museum until it was turned into the University of Maryland Faculty Club in 1954. After another half-century serving as a focal point of dining and special event activities on campus, the Rossborough Inn was converted once again, this time as administrative office space. The decades of the 1930s-1940s were a pivotal period for the University of Maryland. The Rossborough Inn played a crucial role in helping President Harry “Curly” Byrd promote his vision of transforming the university from its agricultural roots to a major academic institution. Over 15 new buildings were erected, following popular Colonial Revival architectural designs. Along with restoring the Rossborough Inn to evoke its historic past, the nearby Dairy building was dressed in Colonial Revival finery, and by 1941 the gardens and landscape surrounding the buildings were configured to provide a new formal pedestrian entry to campus. One of the primary statements of significance for the Rossborough Inn is its pre-eminent place within the ceremonial campus entrance. The ensemble composed of the inn building, Turner Hall (formerly the Dairy), and the surrounding area, remains largely intact and deserves to be recognized and preserved as a significant designed historic landscape. We believe that there are opportunities to preserve and enhance the Rossborough Inn and the historic landscape as prominent features of the university, while respecting the character and the contributions of the oldest building on the campus

    New Era in Designing and Governing Cooling Intensity of Liquid Quenchants to Decrease Distortion During Hardening of Steel Parts

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    It was proved in last decade that very intensive and uniform cooling eliminates quench crack formation and significantly decreases distortion of quenched steel parts as compared with their slow cooling in mineral oils. That opened a new era in design ing and governing cooling intensity of liquid quenchants for strengthening steel parts and decrease their distortion after quenching. The new approaches were developed by authors to provide accelerated and uniform cooling steel parts during quenching by creation on their surface thin insulating layers. For this purpose low concentration of water polymer solutions of inverse solubility are used as a quenchant. More information on cooling intensity of Poly (Alkylene Glycol) polymers (PAG) solutions one can find in a well known book (Totten et al., 1993). Along with decreasing distortion of steel parts, such approach decreases cost of bath’s coolant which less affects environment. It is shown in presentation that accelerated cooling should be interrupted at proper time to provide self tempering, fix compressive residual stresses, decrease more distortion and prevent quench crack formation. To govern process of quenching and make cooling interruption, software IQCalc2 was developed

    Introduction

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    [No abstract available

    Resolving Stellar Populations outside the Local Group: MAD observations of UKS2323-326

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    We present a study aimed at deriving constraints on star formation at intermediate ages from the evolved stellar populations in the dwarf irregular galaxy UKS2323-326. These observations were also intended to demonstrate the scientific capabilities of the multi-conjugated adaptive optics demonstrator (MAD) implemented at the ESO Very Large Telescope as a test-bench of adaptive optics (AO) techniques. We perform accurate, deep photometry of the field using J and Ks band AO images of the central region of the galaxy. The near-infrared (IR) colour-magnitude diagrams clearly show the sequences of asymptotic giant branch (AGB) stars, red supergiants, and red giant branch (RGB) stars down to ~1 mag below the RGB tip. Optical-near-IR diagrams, obtained by combining our data with Hubble Space Telescope observations, provide the best separation of stars in the various evolutionary stages. The counts of AGB stars brighter than the RGB tip allow us to estimate the star formation at intermediate ages. Assuming a Salpeter initial mass function, we find that the star formation episode at intermediate ages produced ~6x10^5 M_sun of stars in the observed region.Comment: 4 pages, 4 figures, Accepted for publication in A&A Letter

    A near-infrared study of AGB and red giant stars in the Leo I dSph galaxy

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    A near-infrared imaging study of the evolved stellar populations in the dwarf spheroidal galaxy Leo I is presented. Based on JHK observations obtained with the WFCAM wide-field array at the UKIRT telescope, we build a near-infrared photometric catalogue of red giant branch (RGB) and asymptotic giant branch (AGB) stars in Leo I over a 13.5 arcmin square area. The V-K colours of RGB stars, obtained by combining the new data with existing optical observations, allow us to derive a distribution of global metallicity [M/H] with average [M/H] = -1.51 (uncorrected) or [M/H] = -1.24 +/- 0.05 (int) +/- 0.15 (syst) after correction for the mean age of Leo I stars. This is consistent with the results from spectroscopy once stellar ages are taken into account. Using a near-infrared two-colour diagram, we discriminate between carbon- and oxygen-rich AGB stars and obtain a clean separation from Milky Way foreground stars. We reveal a concentration of C-type AGB stars relative to the red giant stars in the inner region of the galaxy, which implies a radial gradient in the intermediate-age (1-3 Gyr) stellar populations. The numbers and luminosities of the observed carbon- and oxygen-rich AGB stars are compared with those predicted by evolutionary models including the thermally-pulsing AGB phase, to provide new constraints to the models for low-metallicity stars. We find an excess in the predicted number of C stars fainter than the RGB tip, associated to a paucity of brighter ones. The number of O-rich AGB stars is roughly consistent with the models, yet their predicted luminosity function is extended to brighter luminosity. It appears likely that the adopted evolutionary models overestimate the C star lifetime and underestimate their K-band luminosity.Comment: MNRAS, accepte

    The innate immune response of self-assembling silk fibroin hydrogels

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    Silk has a long track record of use in humans, and recent advances in silk fibroin processing have opened up new material formats. However, these new formats and their applications have subsequently created a need to ascertain their biocompatibility. Therefore, the present aim was to quantify the haemocompatibility and inflammatory response of silk fibroin hydrogels. This work demonstrated that self-assembled silk fibroin hydrogels, as one of the most clinically relevant new formats, induced very low blood coagulation and platelet activation but elevated the inflammatory response of human whole blood in vitro. In vivo bioluminescence imaging of neutrophils and macrophages showed an acute, but mild, local inflammatory response which was lower than or similar to that induced by polyethylene glycol, a benchmark material. The time-dependent local immune response in vivo was corroborated by histology, immunofluorescence and murine whole blood analyses. Overall, this study confirms that silk fibroin hydrogels induce a similar immune response to that of PEG hydrogels, while also demonstrating the power of non-invasive bioluminescence imaging for monitoring tissue responses

    Microstructural evolution in solution heat treatment of gas- atomised Al alloy (7075) powder for cold spray

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    Cold gas dynamic spray is being explored as a repair technique for high-value metallic components, given its potential to produce pore and oxide-free deposits of between several micrometers and several millimeters thick with good levels of adhesion and mechanical strength. However, feedstock powders for cold spray experience rapid solidification if manufactured by gas atomization and hence can exhibit non-equilibrium microstructures and localized segregation of alloying elements. Here, we used sealed quartz tube solution heat treatment of a precipitation hardenable 7075 aluminum alloy feedstock to yield a consistent and homogeneous powder phase composition and microstructure prior to cold spraying, aiming for a more controllable heat treatment response of the cold spray deposits. It was shown that the dendritic microstructure and solute segregation in the gas-atomized powders were altered, such that the heat-treated powder exhibits a homogeneous distribution of solute atoms. Micro-indentation testing revealed that the heat-treated powder exhibited a mean hardness decrease of nearly 25% compared to the as received powder. Deformation of the powder particles was enhanced by heat treatment, resulting in an improved coating with higher thickness (* 300 lm compared to * 40 um for untreated feedstock). Improved particle–substrate bonding was evidenced by formation of jets at the particle boundaries
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