Magnetostriction of single crystal and polycrystalline Tb0.60Dy0.40 at cryogenic temperatures

At cryogenic temperatures, single crystals of TbDy alloys exhibit giant magnetostrictions of nearly 9000 ppm, making these materials promising for engineering service in cryogenic actuators, valves, and positioners. The preparation of single crystals is difficult and costly. Preliminary results on the magnetostriction of textured polycrystalline materials are presented here. For instance, polycrystalline Tb0.60Dy0.40, plane-rolled (one direction of applied stress) to induce crystallographic texture, has shown magnetostrictions at 77 K of 3000 ppm for an applied field of 4.5 kOe and an applied load of 23 MPa, or 48% that of a single crystal under similar conditions. Comparisons are presented between the magnetostrictive response of plane- and form-rolled (two orthogonal directions of applied stress) polycrystalline Tb0.60Dy0.40 at 10 and 77 K. It is reported that at 10 K plane-rolled Tb0.60Dy0.40 exhibits 1600 ppm magnetostriction at an applied field of 4.4 kOe with a minimal applied load of 0.28 MPa. An observed restoration of the initial unstrained state may be a useful feature of polycrystalline materials for engineering service. Finally it is reported that thermal expansion measurements provide a measure of crystallographic texture for comparison with the magnetostriction

Solar generation and storage of O2 (a 1 delta g)

An investigation was performed of the technical steps required to design a solar powered oxygen-iodine laser. Singlet delta oxygen is formed upon transfer of energy from selected photoexcited dye molecules to ground state molecular oxygen and then is concentrated and stored as an endoperoxide by reaction with an aromatic hydrocarbon. The endoperoxide, when heated, releases singlet oxygen in high yield thus providing a regenerable source of laser fuel. Energy transfer from dye molecules to molecular oxygen was investigated. When dye molecules were adsorbed to polymer substrates it was observed that the dye became embedded in the polymer matrix. Porphin dyes were incorporated into films of 1,4-dimethyl-2-poly(vinylnaphthalene), 2PVN. An endoperoxide was formed when porphin-doped 2PVN was exposed to visible radiation. This demonstrates the possibility of generating singlet oxygen using solar energy and concentrating and storing it in one simple step. Transport of energy by exciton migration in polycrystalline dye films was also investigated

The Montage Image Mosaic Service: Custom Image Mosaics On-Demand

The Montage software suite has proven extremely useful as a general engine for reprojecting, background matching, and mosaicking astronomical image data from a wide variety of sources. The processing algorithms support all common World Coordinate System (WCS) projections and have been shown to be both astrometrically accurate and flux conserving. The background ‘matching’ algorithm does not remove background flux but rather finds the best compromise background based on all the input and matches the individual images to that. The Infrared Science Archive (IRSA), part of the Infrared Processing and Analysis Center (IPAC) at Caltech, has now wrapped the Montage software as a CGI service and provided a compute and request management infrastructure capable of producing approximately 2 TBytes / day of image mosaic output (e.g. from 2MASS and SDSS data). Besides the basic Montage engine, this service makes use of a 16-node LINUX cluster (dual processor, dual core) and the ROME request management software developed by the National Virtual Observatory (NVO). ROME uses EJB/database technology to manage user requests, queue processing and load balance between users, and managing job monitoring and user notification. The Montage service will be extended to process userdefined data collections, including private data uploads

As-built design specifications of the LANDSAT Imagery Verification and Extraction System (LIVES). Volume 1: Test and appendices

There are no author-identified significant results in this report

Interpretation, translation and intercultural communication in refugee status determination procedures in the UK and France

This article explores the interplay between language and intercultural communication within refugee status determination procedures in the UK and France, using material taken from ethnographic research that involved a combination of participant observation, semi-structured interviews and documentary analysis in both countries over a two-year period (2007–2009). It is concerned, in particular, to examine the role played by interpreters in facilitating intercultural communication between asylum applicants and the different administrative and legal actors responsible for assessing or defending their claims. The first section provides an overview of refugee status determination procedures in the UK and France, introducing the main administrative and legal contexts of the asylum process within which interpreters operate in the two countries. The second section compares the organisation of interpreting services, codes of conduct for interpreters and institutional expectations about the nature of interpreters’ activity on the part of the relevant UK and French authorities. The third section then explores some of the practical dilemmas for interpreters and barriers to communication that exist in refugee status determination procedures in the two countries. The article concludes by emphasising the complex and active nature of the interpreter's role in UK and French refugee status determination procedures

STUDIES ON THYMUS FUNCTION : I. COOPERATIVE EFFECT OF THYMIC FUNCTION AND LYMPHOHEMOPOIETIC CELLS IN RESTORATION OF NEONATALLY THYMECTOMIZED MICE

Immunological restoration of 45-day old, neonatally thymectomized C3Hf mice by treatment with humoral thymic function (thymoma grafts, thymus or thymoma in diffusion chambers) ranges from 0 to 12% and is difficult to acheive. When small numbers (5–20 x 106) of young adult lymphohemopoietic cells, ineffective by themselves, are given in association with humoral thymic function, a cooperative effect is observed and restoration ranges from 30 to 60%. With a particular cell dosage (20 x 106), effectivity for cooperation with thymic function was the following in decreasing order: spleen, lymph nodes, thoracic duct cells, bone marrow, blood leukocytes, thymus, and Peyer's patch cells. Comparable results were obtained using spleen, thymus, and hemopoietic liver from newborn donors in association with thymic function. For similar cell dosages, newborn thymus cells were more effective than adult thymus in their cooperative effect with thymic function. Dispersed thymus cells in association with young adult bone marrow or newborn hemopoietic liver cells showed no synergism for the cooperative effect with thymic function in the present model. Using hemiallogeneic cells (F1 hybrid into parent) it was possible to show that restoration was mediated by proliferative expansion of the injected cells. This was indicated by specific tolerance to tissues of the other parental strain and by cellular chimerism, especially of lymphoid tissues, as indicated by chromosome markers and absence of significant numbers of immunocompetent cells of host origin. A population of paritally differentiated cells of hemopoietic origin, termed postthymic, sensitive to humoral activity of the thymus and present in the lymphohemopoietic tissues of adult and newborn mice is postulated to explain our results. These cells are postthymic and thymus dependent in the sense that they already received thymic influence, probably through traffic, and are incapable of self-renewal in absence of the thymus. Sensitivity to humoral activity of the thymus is characterized by proliferative expansion and/or a differentiative process eventually leading to larger numbers of competent cells

Connecting the time domain community with the Virtual Astronomical Observatory

The time domain has been identified as one of the most important areas of astronomical research for the next decade. The Virtual Observatory is in the vanguard with dedicated tools and services that enable and facilitate the discovery, dissemination and analysis of time domain data. These range in scope from rapid notifications of time-critical astronomical transients to annotating long-term variables with the latest modeling results. In this paper, we will review the prior art in these areas and focus on the capabilities that the VAO is bringing to bear in support of time domain science. In particular, we will focus on the issues involved with the heterogeneous collections of (ancillary) data associated with astronomical transients, and the time series characterization and classification tools required by the next generation of sky surveys, such as LSST and SKA.Comment: Submitted to Proceedings of SPIE Observatory Operations: Strategies, Processes and Systems IV, Amsterdam, 2012 July 2-

STUDIES ON THYMUS FUNCTION : III. DURATION OF THYMIC FUNCTION

The immune functions of neonatally thymectomized C3Hf mice exposed only temporarily to thymus function show a progressive decay with time in the absence of the thymus. The immune responses studied at different ages in the range of 100–600 days were: first-set rejection of H-2-compatible and incompatible skin allografts, second-set rejection of skin allografts, capacity of spleen cells to produce graft-versus-host reactions in F1 hybrids, resistance to infection with mouse hepatitis virus, and response of spleen cells to phytohemagglutinin in vitro. These long-term studies had the purpose of determining the duration of the restoration induced by thymus function when the mice were exposed only temporarily to it. Different models were used but the two basic ones were: (a) mice grafted intraperitoneally at 15 days of age with a syngeneic thymus that was removed surgically at 10, 20, or 30 days after grafting, and (b) mice grafted at 15 days of age with allogeneic strain A thymoma or C57BL thymus, these representing situations in which there is spontaneous rejection of the restoring graft. In all the experimental models used, the animals were restored when tested at 100 days of age, but progressively became immunologically incapacitated at 200–300 days of age. From the more controlled experiments in which the restoring thymus graft was removed surgically, the following conclusions can be drawn. (a) A short exposure to a thymus graft can produce restoration of immune functions in neonatally thymectomized mice, but this restoration is not self-sustaining in the absence of the thymus and declines progressively with age. The decline usually starts at 200–300 days of age. (b) This was especially clear in experiments in which the same animal was tested twice in its lifetime for capacity to produce graft-versus-host reactions; these animals were competent at 100 days and became incompetent at 400 days of age. (c) The shortest period of thymic exposure studied was 10 days; if vascularization of the graft is taken into account, 2–3 days of thymic function are sufficient to produce restoration. (d) The immune decay observed in the thymectomized animals exposed temporarily to thymus was more profound than the physiological decay of immunity observed in control animals of similar age. (e) Of all the tests studied, the response of spleen cells to phytohemagglutinin was to be preserved the longest in animals exposed only temporarily to thymic function. The present results were interpreted in accordance with our previous findings indicating that a population of postthymic cells can be developed by temporary exposure of neonatally thymectomized animals to thymic function, but that this population is not self-sustaining in the absence of thymus and progressively decays by physiological attrition