3,716 research outputs found

    Space station thermal control surfaces. Volume 1: Interim report

    Get PDF
    The U.S. space program goals for long-duration manned missions place particular demands on thermal-control systems. The objective of this program is to develop plans which are based on the present thermal-control technology, and which will keep pace with the other space program elements. The program tasks are as follows: (1) requirements analysis, with the objectives to define the thermal-control-surface requirements for both space station and 25 kW power module, to analyze the missions, and to determine the thermal-control-surface technology needed to satisfy both sets of requirements; (2) technology assessment, with the objectives to perform a literature/industry survey on thermal-control surfaces, to compare current technology with the requirements developed in the first task, and to determine what technology advancements are required for both the space station and the 25 kW power module; and (3) program planning that defines new initiative and/or program augmentation for development and testing areas required to provide the proper environment control for the space station and the 25 kW power module

    Infrared-temperature variability in a large agricultural field

    Get PDF
    The combined effect of water carved gullies, varying soil color, moisture state of the soil and crop, nonuniform phenology, and bare spots was measured for commercially grown barley planted on varying terrain. For all but the most rugged terrain, over 80% of the area within 4, 16, 65, and 259 ha cells was at temperatures within 3 C of the mean cell temperature. The result of using relatively small, 4 ha instantaneous field of views for remote sensing applications is that either the worst or the best of conditions is often observed. There appears to be no great advantage in utilizing a small instantaneous field of view instead of a large one for remote sensing of crop canopy temperatures. The two alternatives for design purposes are then either a very high spatial resolution, of the order of a meter or so, where the field is very accurately temperature mapped, or a low resolution, where the actual size seems to make little difference

    Airborne observed solar elevation and row direction effects on the near-IR/red ratio of cotton

    Get PDF
    An airborne multispectral scanner was used to obtain data over two adjacent cotton fields having rows perpendicular to one another, at three times of day (different solar elevations), and on two dates (different plant size). The near IR/red ratios were displayed in image form, so that within-field variations and differences between fields could be easily assessed. The ratio varied with changing Sun elevation for north-south oriented rows, but no variation was detected for east-west oriented rows

    Space station thermal control surfaces

    Get PDF
    Mission planning documents were used to analyze the radiator design and thermal control surface requirements for both space station and 25-kW power module, to analyze the missions, and to determine the thermal control technology needed to satisfy both sets of requirements. Parameters such as thermal control coating degradation, vehicle attitude, self eclipsing, variation in solar constant, albedo, and Earth emission are considered. Four computer programs were developed which provide a preliminary design and evaluation tool for active radiator systems in LEO and GEO. Two programs were developed as general programs for space station analysis. Both types of programs find the radiator-flow solution and evaluate external heat loads in the same way. Fortran listings are included

    An Intelligent Advisor for City Traffic Policies

    Get PDF
    Nowadays, city streets are populated not only by private vehicles but also by public transport, fleets of workers, and deliveries. Since each vehicle class has a maximum cargo capacity, we study in this article how authorities could improve the road traffic by endorsing long term policies to change the different vehicle proportions: sedans, minivans, full size vans, trucks, and motorbikes, without losing the ability of moving cargo throughout the city. We have performed our study in a realistic scenario (map, road traffic characteristics, and number of vehicles) of the city of Malaga and captured the many details into the SUMO microsimulator. After analyzing the relationship between travel times, emissions, and fuel consumption, we have defined a multiobjective optimization problem to be solved, so as to minimize these city metrics. Our results provide a scientific evidence that we can improve the delivery of goods in the city by reducing the number of heavy duty vehicles and fostering the use of vans instead.Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tech. This research has been partially funded by the Spanish MINECO and FEDER projects TIN2014-57341-R, TIN2016-81766-REDT, and TIN2017-88213-R. University of Malaga, Andalucia TECH. Daniel H. Stolfi is supported by a FPU grant (FPU13/00954) from the Spanish MECD. Christian Cintrano is supported by a FPI grant (BES-2015-074805) from Spanish MINECO

    Unpaid community volunteers – effective providers of directly observed therapy (DOT) in rural South Africa

    Get PDF
    Objective. To illustrate successes and difficulties for the South African National Tuberculosis Progranune in a rural area.Design. Prospective cohort study.Setting. Sekhukhuneland, Provincial Health Service Southern Region, Northern Province, South Africa.Subjects. All patients diagnosed with tuberculosis (TB) in thecatchment area of four rural hospitals between January 1997 and June 1999,Main outcome measures. Standard outcomes for TB treatment as defined by the World Health Organisation. Treatment failure, treatment interruption and death were grouped as poor outcomes.Results. One thousand four hundred and seventy-six people were diagnosed with TB. The majority (76%) had smearpositive pulmonary disease. Treatment was given by directly observed therapy (DOT) throughout in all but 15 instances. Excluding 10 subjects with known multidrug-resistant TB (MDRTB), 723 (66%) were cured, 68 (6%) completed treatment, 73 (7%) interrupted treatment, 37 (3%) failed treatment, 66 (6%) transferred out, and 134 (12%) died. Of the 920 initially smear-positive patients who survived the first 2 months to receive DOT in the community, 693 (75%) were supervised by unpaid community volunteers. Poor outcomes were no more common among patients supervised by these volunteers than among patients supervised by professional health care workers. Male gender (odds ratio 1.38,95% confidence interval 1.02, 1.87) was significantly associated with a poor outcome.Conclusion. Although there were difficulties, the national progranune was successfully applied with no additional funds or facilities. Explanations for the high death rate and poor outcomes for men need to be found. Great efforts will be required to preserve the quality of the TB programme if it is devolved to primary care level

    An Early Catalog of Planet Hosting Multiple Star Systems of Order Three and Higher

    Full text link
    We present a catalog (status July 1, 2022) of triple and higher order systems identified containing exoplanets based on data from the literature, including various analyses. We explore statistical properties of the systems with focus on both the stars and the planets. So far, about 30 triple systems and one to three quadruple systems, including (mildly) controversial cases, have been found. The total number of planets is close to 40. All planet-hosting triple star systems are highly hierarchic, consisting of a quasi-binary complemented by a distant stellar component, which is in orbit about the common center of mass. Furthermore, the quadruple systems are in fact pairs of close binaries (``double-doubles"), with one binary harboring a planet. For the different types of star-planet systems, we introduce a template for the classifications of planetary orbital configurations in correspondence to the hierarchy of the system and the planetary host. The data show that almost all stars are main-sequence stars, as expected. However, the stellar primaries tend to be more massive (i.e., corresponding to spectral types A, F, and G) than expected from single star statistics, a finding also valid for stellar secondaries but less pronounced. Tertiary stellar components are almost exclusively low-mass stars of spectral type M. Almost all planets have been discovered based on either the Radial Velocity or the Transit method. Both gas giants (the dominant type) and terrestrial planets (including super-Earths) have been identified. We anticipate the expansion of this data base in the light of future planetary search missions.Comment: Accepted by ApJS; 59 pages, including 11 figures and 12 table

    Analytic Inversion of Emission Lines of Arbitrary Optical Depth for the Structure of Supernova Ejecta

    Get PDF
    We derive a method for inverting emission line profiles formed in supernova ejecta. The derivation assumes spherical symmetry and homologous expansion (i.e., v(r)rv(r) \propto r), is analytic, and even takes account of occultation by a pseudo-photosphere. Previous inversion methods have been developed which are restricted to optically thin lines, but the particular case of homologous expansion permits an analytic result for lines of {\it arbitrary} optical depth. In fact, we show that the quantity that is generically retrieved is the run of line intensity IλI_\lambda with radius in the ejecta. This result is quite general, and so could be applied to resonance lines, recombination lines, etc. As a specific example, we show how to derive the run of (Sobolev) optical depth τλ\tau_\lambda with radius in the case of a pure resonance scattering emission line.Comment: 6 pages, no figures, to appear in Astrophysical Journal Letters, requires aaspp4.sty to late

    Acquisition of Laser Scanning Confocal Microscope for Biological and Materials Research

    Get PDF
    Biological and Materials research at the University of Maine will be strongly impacted by the acquisition of a Laser Scanning Electron Microscope as a result of this NSF-MRI award. The Leica confocal unit, along with an upright and inverted microscope and digital camera will form a multi-user facility for campus researchers working with a range of biological and materials problems. Initially, 13 faculty members from 8 academic departments have projects planned for the instrument. The microscope will be the first of its kind on the University of Maine campus. A wide range of research problems will be attacked through use of this instrument in conjunction with existing instrumentation. Examples include: Biological research projects involve understanding the maintenance of bone structure through mapping of the distribution of proteins, the reproduction of algae in troubled marine ecosystems, and bacterial or viral diseases of fish. Additionally, improved understanding of fundamental microbe-plant symbiosis and wood decay processes will allow for future applied research to attack economically and socially important problems. The development of biofilms for sensors of biological and chemical warfare agents will be aided through film characterization using this instrument. This $10 million effort is a University/private industry/Department of Defense partnership. Materials-related research includes determination of morphology and fracture of wood-based composite material, microfracture characterization of cement-based materials, and characterization of paper roughness. This work, along with environmental scanning electron microscopy and X-ray microtomography, is focused on the measurement of microstructural mechanisms of material behavior and its improvement through subsequent processing changes. The ultimate benefit will include more efficient use of natural resources, better performance and lowered product costs
    corecore