23,236 research outputs found

    Apollo 8 colorimetry

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    Lunar colorimeter image processing aboard Apollo

    The construction of colorimetry by committee

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    This paper explores the confrontation of physical and contextual factors involved in the emergence of the subject of color measurement, which stabilized in essentially its present form during the interwar period. The contentions surrounding the specialty had both a national and a disciplinary dimension. German dominance was curtailed by American and British contributions after World War I. Particularly in America, communities of physicists and psychologists had different commitments to divergent views of nature and human perception. They therefore had to negotiate a compromise between their desire for a quantitative system of description and the perceived complexity and human-centeredness of color judgement. These debates were played out not in the laboratory but rather in institutionalized encounters on standards committees. Groups such as this constitute a relatively unexplored historiographic and social site of investigation. The heterogeneity of such committees, and their products, highlight the problems of identifying and following such ephemeral historical 'actors'

    Heavy quark colorimetry of QCD matter

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    We consider propagation of heavy quarks in QCD matter. Because of large quark mass, the radiative quark energy loss appears to be qualitatively different from that of light quarks at all energies of practical importance. Finite quark mass effects lead to an in-medium enhancement of the heavy-to-light D/\pi ratio at moderately large (5--10 GeV) transverse momenta. For hot QCD matter a large enhancement is expected, whose magnitude and shape are exponentially sensitive to the density of colour charges in the medium.Comment: 15 pages, 4 figures, LaTe

    From eye to machine: shifting authority in color measurement

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    Given a subject so imbued with contention and conflicting theoretical stances, it is remarkable that automated instruments ever came to replace the human eye as sensitive arbiters of color specification. Yet, dramatic shifts in assumptions and practice did occur in the first half of the twentieth century. How and why was confidence transferred from careful observers to mechanized devices when the property being measured – color – had become so closely identified with human physiology and psychology? A fertile perspective on the problem is via the history of science and technology, paying particular attention to social groups and disciplinary identity to determine how those factors affected their communities’ cognitive territory. There were both common and discordant threads motivating the various technical groups that took on the problems of measuring light and color from the late nineteenth century onwards, and leading them towards the development of appropriate instruments for themselves. The transition from visual to photoelectric methods <i>could</i> be portrayed as a natural evolution, replacing the eye by an alternative roviding more sensitivity and convenience – indeed, this is the conventional positivist view propounded by technical histories. However, the adoption of new measurement technologies seldom is simple, and frequently has a significant cultural component. Beneath this slide towards automation lay a raft of implicit assumptions about objectivity, the nature of the observer, the role of instruments, and the trade-offs between standardization and descriptive power. While espousing rational arguments for a physical detector of color, its proponents weighted their views with tacit considerations. The reassignment of trust from the eye to automated instruments was influenced as much by the historical context as by intellectual factors. I will argue that several distinct aspects were involved, which include the reductive view of color provided by the trichromatic theory; the impetus provided by its association with photometry; the expanding mood for a quantitative and objective approach to scientific observation; and, the pressures for commercial standardization. As suggested by these factors, there was another shift of authority at play: from one technical specialism to another. The regularization of color involved appropriation of the subject by a particular set of social interests: communities of physicists and engineers espousing a ‘physicalist’ interpretation, rather than psychologists and physiologists for whom color was conceived as a more complex phenomenon. Moreover, the sources for automated color measurement, and instrumentation for measuring color, were primarily from the industrial sphere rather than from academic science. To understand these shifts, then, this chapter explores differing views of the importance of observers, machines and automation

    The botany and proximate analyses of some edible species of the New Zealand flora : a thesis presented in partial fulfilment of the requirement for the degree of Master of Science in Plant Biology at Massey University

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    1. The edible organs of some New Zealand plant species have been assessed at light microscope level for their botanical basis, and for their nutritional basis by proximate analysis and Plasma Emission Spectrometry. 2. The species investigated, listed by Colenso (1880) as the most valued plant foods of the pre-European Maori, were: Pteridium esculentum (rhizome), Corynocarpus laevigatus (kernel), Elaeocarpus dentatus, (pericarp), Sonchus asper (herb), Calystegia sepium (rhizome), Cyathea medullaris (frond stipe), Cordyline australis (leaf bases, root), Rhopalostylis sapida (apical shoot), Typha orientalis (pollen and rhizome), Beilschmiedia tawa (kernel), Marattia salicina (rhizomal scale), Porphyra columbina (frond), Auricularia polytricha (basidiocarp), Arthropodium cirratum (rhizome), Bolboschoenus fluviatilis (rhizomal tuber), Gastrodia cunninghamii (rhizome) and Asplenium bulbiferum (immature frond). 3. Specimens were collected at the appropriate traditional seasons (except for Gastrodia cunninghamii) and samples prepared by freeze-drying and milling. Samples were also prepared of the cooked organs of Corynocarpus laevigatus, Elaeocarpus dentatus, Sonchus asper, Cyathea medullaris, Beilschmiedia tawa and Porphyra columbina. 4. Analytical determinations were made for lipid, by extraction with di-ethyl ether; nitrogen, by micro-Kjeldahl method and colorimetric measurement of ammonia using indophenol; protein, by Bradford procedure using Coomassie Brilliant Blue and colorimetry; dietary fibre, by Englyst procedure using enzymatic digestion and colorimetry; soluble sugar, by acid hydrolysis and colorimetry; and starch, by enzymatic digestion and colorimetry. 5. Botanical investigations were made following histological procedures and microtechnique using paraffin wax embedding and staining with safranin and fast green; and by differential staining of hand-cut sections using Sudan Blue, iodine and Coomassie Brilliant Blue. 6. Analytical determinations were made for 23 trace, minor and major constituent elements, using inductively-coupled argon plasmas in a simultaneous emission spectrometer. 7. Proximate analyses showed high levels of lipid in Corynocarpus laevigatus, Cyathea medullaris, and Sonchus asper, of protein in Corynocarpus laevigatus, Sonchus asper, Rhopalostylis sapida, Typha orientalis (pollen) and Asplenium bulbiferum; of dietary fibre in Auricularia polytricha, Beilschmiedia tawa, Marattia salicina (root) and Porphyra columbina (uncooked); of soluble sugar in Cyathea medullaris, Cordyline australis (leaf bases and root), Typha orientalis (rhizomes and pollen) and Pteridium esculentum; and of starch in Corynocarpus laevigatus, Elaeocarpus dentatus, Marattia salicina, Calystegia sepium and Gastrodia cunninghamii. 8. High levels of essential minerals and trace elements were measured in many samples, and some excess levels of toxic metals were recorded. 9. The nutritional and ethnobotanical aspects of a pre-European Maori diet were related to the analytical and botanical findings of the investigation

    Apparatus enables automatic microanalysis of body fluids

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    Apparatus will automatically and quantitatively determine body fluid constituents which are amenable to analysis by fluorometry or colorimetry. The results of the tests are displayed as percentages of full scale deflection on a strip-chart recorder. The apparatus can also be adapted for microanalysis of various other fluids

    Colorimetry technique for scalable characterization of suspended graphene

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    Previous statistical studies on the mechanical properties of chemical-vapor-deposited (CVD) suspended graphene membranes have been performed by means of measuring individual devices or with techniques that affect the material. Here, we present a colorimetry technique as a parallel, non-invasive, and affordable way of characterizing suspended graphene devices. We exploit Newton rings interference patterns to study the deformation of a double-layer graphene drum 13.2 micrometer in diameter when a pressure step is applied. By studying the time evolution of the deformation, we find that filling the drum cavity with air is 2-5 times slower than when it is purged

    Digital Color Imaging

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    This paper surveys current technology and research in the area of digital color imaging. In order to establish the background and lay down terminology, fundamental concepts of color perception and measurement are first presented us-ing vector-space notation and terminology. Present-day color recording and reproduction systems are reviewed along with the common mathematical models used for representing these devices. Algorithms for processing color images for display and communication are surveyed, and a forecast of research trends is attempted. An extensive bibliography is provided

    Studies of relationships among outer solar system small bodies and related objects

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    This program involves telescopic observations of colorimetry, spectroscopy, and photometry of small bodies of the solar system, emphasizing possible relationships among outer solar system asteroids, comets, and certain satellites. Earth approacher targets of opportunity and lab spectroscopic studies are included
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