10,964 research outputs found

    Indium antimonide crystal growth experiment M562

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    It was established that ideal diffusion controlled steady state conditions, never accomplished on earth, were achieved during the growth of Te-doped InSb crystals in Skylab. Surface tension effects led to nonwetting conditions under which free surface solidification took place in confined geometry. It was further found that, under forced contact conditions, surface tension effects led to the formation of surface ridges (not previously observed on earth) which isolated the growth system from its container. In addition, it was possible, for the first time, to identify unambiguously: the origin of segregation discontinuities associated with facet growth, the mode of nucleation and propagation of rotational twin boundaries, and the specific effect of mechanical-shock perturbations on segregation. The results obtained prove the advantageous conditions provided by outer space. Thus, fundamental data on solidification thought to be unattainable because of gravity-induced interference on earth are now within reach

    PROFITABILITY OF CONVENIENCE MARKET DAIRY DEPARTMENTS

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    Examines return on investment to dairy departments in a sample of convenience markets and makes recommendations for profit improvement.Agribusiness,

    Solidification (crystal growth) in the presence of gravitational forces

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    The surface tension behavior of doped and undoped InSb melts was investigated as well as their temperature and composition dependence. Surface tension in InSb melts was determined using the sessile-drop technique covering the temperature range from 530 C to 880 C. A linear regression of the data obtained shows that the temperature dependence of sigma is 392- (T-530) x (7000) plus or minus 10 dyne/cm. The d sigma/d Tau for intrinsics InSb is less than that previously reported. On the basis of the surface tension data obtained, it is concluded that surface tension induced convective flow velocities in InSb under reduced gravity conditions range from zero to at most 1 cm/sec. Accordingly, no interference with dopant segregation can be expected during growth in space because the momentum boundary layer (at the crystal melt interface) associated with any Marangoni-type convective flows would, at the given growth rate, be significantly larger than the predicted diffusion boundary layer thickness

    Preparation of homogeneous vitreous materials for electronic and optical devices

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    Vitreous material builds up as series of solidified layers on inside walls of sealed quartz ampoule containing molten constituents of material, and forms well defined shapes to close dimensional tolerances. Ampoules are made of material which does not react with melt and has lower thermal expansion coefficient than solidified layer

    The nature of the red disk-like galaxies at high redshift: dust attenuation and intrinsically red stellar populations

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    We investigate which conditions of dust attenuation and stellar populations allow models of dusty, continuously star-forming, bulge-less disk galaxies at 0.8<z<3.2 to meet the different colour selection criteria of high-z ``red'' galaxies (e.g. Rc-K>5.3, Ic-K>4, J-K>2.3). As a main novelty, we use stellar population models that include the thermally pulsating Asymptotic Giant Branch (TP-AGB) phase of stellar evolution. The star formation rate of the models declines exponentially as a function of time, the e-folding time being longer than 3 Gyr. In addition, we use calculations of radiative transfer of the stellar and scattered radiation through different dusty interstellar media in order to explore the wide parameter space of dust attenuation. We find that synthetic disks can exhibit red optical/near-infrared colours because of reddening by dust, but only if they have been forming stars for at least about 1 Gyr. Extremely few models barely exhibit Rc-K>5.3, if the inclination i=90 deg and if the opacity 2*tauV>6. Hence, Rc-K-selected galaxies at 1<z<2 most probably are either systems with an old, passively evolving bulge or starbursts. Synthetic disks at 1<z<2 exhibit 4<Ic-K<4.8, if they are seen edge on (i.e. at i about 90 deg) and if 2*tauV>0.5. This explains the large fraction of observed, edge-on disk-like galaxies with Ks4. Finally, models with 2<z<3.2 exhibit 2.3<J-K<3, with no bias towards i about 90 deg and for a large range in opacity (e.g. 2*tauV>1 for i about 70 deg). In conclusion, red disk-like galaxies at 0.8<z<3.2 may not necessarily be dustier than nearby disk galaxies (with 0.5<2*tauV<2) and/or much older than about 1 Gyr. This result is due both to a realistic description of dust attenuation and to the emission contribution by TP-AGB stars... (Abridged)Comment: 16 pages, 8 ps figures, accepted for publication in MNRA

    Magnification relations in gravitational lensing via multidimensional residue integrals

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    We investigate the so-called magnification relations of gravitational lensing models. We show that multidimensional residue integrals provide a simple explanation for the existence of these relations, and an effective method of computation. We illustrate the method with several examples, thereby deriving new magnification relations for galaxy lens models and microlensing (point mass lensing).Comment: 16 pages, uses revtex4, submitted to Journal of Mathematical Physic

    2018 Annual Report

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    In 2018, the Museum of Southwestern Biology (MSB) has continued to improve its profile and impacts, both on the University of New Mexico campus and in the international scientific community. Its collections serve as scientific infrastructure that enhances research, teaching, community service, and public outreach. The MSB is part of the UNM Department of Biology, and the missions of the MSB and the Department are synergistic. MSB houses extensive and rapidly growing collections representing biodiversity of world, primarily from the last halfcentury. MSB has outstanding collections from New Mexico and western North America, but it also has substantial holdings from five other continents around the world. MSB consists of eight divisions, and one special program (the Natural Heritage Program New Mexico). MSB also manages the large federal collection of the US Geological Survey collection, second only the Smithsonian Institution in size among federal collections. The collections enrich education by allowing for scientists, educators, public health professionals, and natural resource managers to investigate climate change, environmental quality, emerging diseases, invasive species, ecology, genomics, and evolution. The databases associated with the MSB\u27s eight collections constitute a significant, accessible informatics resource that grows in value each time scientific research is done using the collections. In these ways, MSB contributes to understanding life on earth, its origins, diversity, function, and relationships with human society and public health. MSB annual reports are archived and accessible via UNM\u27s internet repository: (http://repository.unm.edu/handle/1928/24433).https://digitalrepository.unm.edu/msb_annual_reports/1012/thumbnail.jp

    Paul C. Witt Papers, 1908-1970

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    A Study of the Contribution of the Hymn to the Worship Service

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    The purpose of this study is to determine the values within the hymn and their relative contributions to the worship service of the church. As an element of the worship, the hymn is observed to be incorrectly evaluated and understood. It is hoped that by careful observation and discussion, some new contributions can be added to the fund of knowledge which will aid in man \u27s worship of God

    Jeremy Witt, Baritone, Senior Voice Recital

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