34,287 research outputs found

    Antenna tracking mechanism for geostationary satellites

    Get PDF
    The design and development of a continuous duty cycle antenna tracking mechanism (ATM) for geostationary communications satellites is described. The FACC requirements for an ATM and description of the development mechanism designed and built for the program are presented. The mechanism mechanical configuration and component performance is documented along with its launch and operational constraints. The proposed development tests and the results of computer simulations are discussed. The advantages of this mechanism are its simplicity with inherent reliability, low mass, high stiffness, and ability to accurately point a wide range of antenna sizes

    Use of a Producer Survey to Reconcile Differences in Experiment Station Yield Estimates

    Get PDF
    Average producer practice reveals that the expected returns are greater from dual-purpose wheat grown for both forage and grain than for grain-only wheat. Variety trials report an 11 bushel per acre yield advantage and hence economic advantage for grain-only. Research was conducted to reconcile the inconsistency.direct elicitation method, dual-purpose, simulation, stocker steers, survey, triangular distribution, wheat, Farm Management, Livestock Production/Industries, Q10, Q12,

    A Group of Red, Ly-alpha Emitting, High Redshift Galaxies

    Full text link
    We have discovered two new high redshift (z=2.38) galaxies, near the previously known z=2.38 galaxy 2139-4434 B1 (Francis et al. 1996). All three galaxies are strong Ly-alpha emitters, and have much redder continuum colors (I-K about 5) than other optically-selected high redshift galaxies. We hypothesize that these three galaxies are QSO IIs; radio-quiet counterparts of high redshift radio galaxies, containing concealed QSO nuclei. The red colors are most easily modelled by an old (> 0.5 Gyr), massive (> 10E11 solar masses) stellar population. If true, this implies that at least one galaxy cluster of mass much greater than 3E11 solar masses had collapsed before redshift five.Comment: 12 pages, 2 figures, uses aaspp4 style file. Accepted for publication in Astrophysical Journal Letter

    Psychological health and attitude toward Christianity: a study among pupils attending Catholic schools in the Netherlands

    Get PDF
    This study examines the wider relevance of recent research conducted in England, Northern Ireland and Hong Kong concerning the association between religion and psychological health among young people, by administering translations of the same measures to a sample of 980 pupils attending Catholic secondary schools in the Netherlands. These pupils completed the short-form Revised Eysenck Personality Questionnaire together with the Francis Scale of Attitude toward Christianity. The data confirmed the key finding from previous research that a more positive attitude toward Christianity is associated with lower scores recorded on the psychoticism scale. The implications of these findings are discussed for religious educators

    Work-related psychological health and psychological type among lead elders within the Newfrontiers network of churches in the United Kingdom

    Get PDF
    Building on a series of recent studies concerned with assessing work-related psychological health and psychological type among various groups of church leaders, this study reports new data provided by 134 Lead Elders within the Newfrontiers network of churches in the United Kingdom who completed the Francis Psychological Type Scales (FPTS) together with the two scales of the Francis Burnout Inventory (FBI) concerned with emotional exhaustion and satisfaction in ministry. Compared with other groups of church leaders, Lead Elders within the Newfrontiers network of churches reported lower levels of emotional exhaustion and higher levels of satisfaction in ministry. Compared with other groups of church leaders, there was a higher proportion of extraverts among Lead Elders within the Newfrontiers network of churches. There was only a weak association between psychological type and burnout

    Dynamics of electron currents in nanojunctions with time-varying components and interactions

    Full text link
    We study the dynamics of the electron current in nanodevices where there are time-varying components and interactions. These devices are a nanojunction attached to heat baths and with dynamical electron-phonon interactions and a nanojunction with photon beams incident and reflected at the channel. We use the two-time nonequilibrium Green's functions technique to calculate the time-dependent electron current flowing across the devices. We find that whenever a sudden change occurs in the device, the current takes time to react to the abrupt change, overshoots, oscillates, and eventually settles down to a steady value. With dynamical electron-phonon interactions, the interaction gives rise to a net resistance that reduces the flow of current across the device when a source-drain bias potential is attached. In the presence of dynamical electron-photon interactions, the photons drive the electrons to flow. The direction of flow, however, depends on the frequencies of the incident photons. Furthermore, the direction of electron flow in one lead is exactly opposite to the direction of flow in the other lead thereby resulting in no net change in current flowing across the device.Comment: 7 page
    corecore