Flight deck automation: Promises and realities

Issues of flight deck automation are multifaceted and complex. The rapid introduction of advanced computer-based technology onto the flight deck of transport category aircraft has had considerable impact both on aircraft operations and on the flight crew. As part of NASA's responsibility to facilitate an active exchange of ideas and information among members of the aviation community, a NASA/FAA/Industry workshop devoted to flight deck automation, organized by the Aerospace Human Factors Research Division of NASA Ames Research Center. Participants were invited from industry and from government organizations responsible for design, certification, operation, and accident investigation of transport category, automated aircraft. The goal of the workshop was to clarify the implications of automation, both positive and negative. Workshop panels and working groups identified issues regarding the design, training, and procedural aspects of flight deck automation, as well as the crew's ability to interact and perform effectively with the new technology. The proceedings include the invited papers and the panel and working group reports, as well as the summary and conclusions of the conference

Population III star formation in a Lambda CDM universe, II: Effects of a photodissociating background

We examine aspects of primordial star formation in the presence of a molecular hydrogen-dissociating ultraviolet background. We compare a set of AMR hydrodynamic cosmological simulations using a single cosmological realization but with a range of ultraviolet background strengths in the Lyman-Werner band. This allows us to study the effects of Lyman-Werner radiation on suppressing H2 cooling at low densities as well as the high-density evolution of the collapsing core in a self-consistent cosmological framework. We find that the addition of a photodissociating background results in a delay of the collapse of high density gas at the center of the most massive halo in the simulation and, as a result, an increase in the virial mass of this halo at the onset of baryon collapse. We find that, contrary to previous results, Population III star formation is not suppressed for J$_{21} \geq 0.1$, but occurs even with backgrounds as high as J$_{21} = 1$. We find that H2 cooling leads to collapse despite the depressed core molecular hydrogen fractions due to the elevated H2 cooling rates at $T=2-5 \times 10^3$ K. We observe a relationship between the strength of the photodissociating background and the rate of accretion onto the evolving protostellar cloud core, with higher LW background fluxes resulting in higher accretion rates. Finally, we find that the collapsing halo cores in our simulations do not fragment at densities below $n \sim 10^{10}$ cm$^{-3}$ regardless of the strength of the LW background, suggesting that Population III stars forming in halos with T$_{vir} \sim 10^4$ K may still form in isolation.Comment: 46 pages, 14 figures (9 color). Accepted by the Astrophysical Journal, some minor revision

Overcoming migration during giant planet formation

In the core accretion model, gas giant formation is a race between growth and migration; for a core to become a jovian planet, it must accrete its envelope before it spirals into the host star. We use a multizone numerical model to extend our previous investigation of the "window of opportunity" for gas giant formation within a disk. When the collision cross-section enhancement due to core atmospheres is taken into account, we find that a broad range of protoplanetary disks posses such a window.Comment: 4 pages, 3 figs, accepted to ApJ

Temperature-dependent quantum pair potentials and their application to dense partially ionized hydrogen plasmas

Extending our previous work \cite{filinov-etal.jpa03ik} we present a detailed discussion of accuracy and practical applications of finite-temperature pseudopotentials for two-component Coulomb systems. Different pseudopotentials are discussed: i) the diagonal Kelbg potential, ii) the off-diagonal Kelbg potential iii) the {\em improved} diagonal Kelbg potential, iv) an effective potential obtained with the Feynman-Kleinert variational principle v) the ``exact'' quantum pair potential derived from the two-particle density matrix. For the {\em improved} diagonal Kelbg potential a simple temperature dependent fit is derived which accurately reproduces the ``exact'' pair potential in the whole temperature range. The derived pseudopotentials are then used in path integral Monte Carlo (PIMC) and molecular dynamics (MD) simulations to obtain thermodynamical properties of strongly coupled hydrogen. It is demonstrated that classical MD simulations with spin-dependent interaction potentials for the electrons allow for an accurate description of the internal energy of hydrogen in the difficult regime of partial ionization down to the temperatures of about $60 000$ K. Finally, we point out an interesting relation between the quantum potentials and effective potentials used in density functional theory.Comment: 18 pages, 11 figure

Technique for producing wind-tunnel heat-transfer models

Inexpensive thin skinned wind tunnel models with thermocouples on certain surface areas were fabricated. Thermocouples were designed for measuring aerodynamic heat transfer in wind tunnels

Strangeness in Compact Stars and Signal of Deconfinement

Phase transitions in compact stars are discussed including hyperonization, deconfinement and crystalline phases. Reasons why kaon condensation is unlikely is reviewed. Particular emphasis is placed on the evolution of internal structure with spin-down of pulsars. A signature of a first order phase transition in the timing structure of pulsars which is strong and easy to measure, is identified.Comment: 17 pages, 15 figures, Latex. (Invited Talk at the International Symposium on ``Strangeness In Quark Matter 1997'', Thera (Santorini), Hellas, April 14-18, 1997, To be published in Journal of Physics G (Organizers: A Panagiotou and J. Madsen

Sustainable development of smallholder crop-livestock farming in developing countries

Meeting the growing demand for animal-sourced food, prompted by population growth and increases in average per-capita income in low-income countries, is a major challenge. Yet, it also presents significant potential for agricultural growth, economic development, and reduction of poverty in rural areas. The main constraints to livestock producers taking advantage of growing markets include; lack of forage and feed gaps, communal land tenure, limited access to land and water resources, weak institutions, poor infrastructure and environmental degradation. To improve rural livelihood and food security in smallholder crop-livestock farming systems, concurrent work is required to address issues regarding efficiency of production, risk within systems and development of whole value chain systems. This paper provides a review of several forage basedstudies in tropical and non-tropical dry areas of the developing countries. A central tenet of this paper is that forages have an essential role in agricultural productivity, environmental sustainability and livestock nutrition in smallholder mixed farming systems

The Temperature Evolution of the Spectral Peak in High Temperature Superconductors

Recent photoemission data in the high temperature cuprate superconductor Bi2212 have been interpreted in terms of a sharp spectral peak with a temperature independent lifetime, whose weight strongly decreases upon heating. By a detailed analysis of the data, we are able to extract the temperature dependence of the electron self-energy, and demonstrate that this intepretation is misleading. Rather, the spectral peak loses its integrity above Tc due to a large reduction in the electron lifetime.Comment: 5 pages, revtex, 4 encapsulated postscript figure

Radiation protection by auxin analogues and antiviral agents

Cobalt 60 gamma radiation of male white mice to determine ability of auxin and antiviral agents to provide radiation protectio