11,789 research outputs found
Long distance tracking of birds
The application of radio telemetry techniques to the long distance tracking of birds is discussed. The types of equipment developed and methods for attachment to a bird are described. The operating range of the radio transmitter receiver system is examined, and methods for acquiring and analyzing the data are explained
A high pressure, high temperature combustor and turbine-cooling test facility
A new test facility is being constructed for developing turbine-cooling and combustor technology for future generation aircraft gas turbine engines. Prototype engine hardware will be investigated in this new facility at gas stream conditions up to 2480 K average turbine inlet temperature and 4.14 x 10 to the 6th power n sq m turbine inlet pressure. The facility will have the unique feature of fully automated control and data acquisition through the use of an integrated system of mini-computers and programmable controllers which will result in more effective use of operating time, will limit the number of operators required, and will provide built in self protection safety systems. The facility and the planning and design considerations are described
OBTAINING LOWER AND UPPER BOUNDS ON THE VALUE OF SEASONAL CLIMATE FORECASTS AS A FUNCTION OF RISK PREFERENCES
A methodological approach to obtain bounds on the value of information based on an inexact representation of the decision makerÂ’s utility function is presented. Stochastic dominance procedures are used to derive the bounds. These bounds provide more information than the single point estimates associated with traditional decision analysis approach to valuing information, in that classes of utility functions can be considered instead of one specific utility function. Empirical results for valuing seasonal climate forecasts illustrate that the type of management strategy given by the decision makerÂ’s prior knowledge interacts with the decision makerÂ’s risk preferences to determine the bounds.Risk and Uncertainty,
Engineering multiferroism in CaMnO
From first-principles calculations, we investigate the structural
instabilities of CaMnO. We point out that, on top of a strong
antiferrodistortive instability responsible for its orthorhombic ground-state,
the cubic perovskite structure of CaMnO also exhibit a weak ferroelectric
instability. Although ferroelectricity is suppressed by antiferrodistortive
oxygen motions, we show that it can be favored using strain or chemical
engineering in order to make CaMnO multiferroic. We finally highlight that
the FE instability of CaMnO is Mn-dominated. This illustrates that,
contrary to the common believe, ferroelectricity and magnetism are not
necessarily exclusive but can be driven by the same cation
Effects of gravity on laminar gas jet diffusion flames
Zero gravity effects on laminar gas jet diffusion flame
Strain-induced ferroelectricity in simple rocksalt binary oxides
The alkaline earth binary oxides adopt a simple rocksalt structure and form
an important family of compounds because of their large presence in the earth's
mantle and their potential use in microelectronic devices. In comparison to the
class of multifunctional ferroelectric perovskite oxides, however, their
practical applications remain limited and the emergence of ferroelectricity and
related functional properties in simple binary oxides seems so unlikely that it
was never previously considered. Here, we show using first-principles density
functional calculations that ferroelectricity can be easily induced in simple
alkaline earth binary oxides such as barium oxide (BaO) using appropriate
epitaxial strains. Going beyond the fundamental discovery, we show that the
functional properties (polarization, dielectric constant and piezoelectric
response) of such strained binary oxides are comparable in magnitude to those
of typical ferroelectric perovskite oxides, so making them of direct interest
for applications. Finally, we show that magnetic binary oxides such as EuO,
with the same rocksalt structure, behave similarly to the alkaline earth
oxides, suggesting a route to new multiferroics combining ferroelectric and
magnetic properties
Baseball\u27s Conflict of Law
There is a conflict of laws in Major League Baseball, resulting from the National League’s refusal to adopt the Designated Hitter Rule, and the American League’s refusal to abandon it. As is often the case when rules of two jurisdictions diverge, the conflict reflects a difference in priorities and philosophies between the two leagues. By adopting and maintaining the Designated Hitter Rule, the American League demonstrates its preference for offensive output at the expense of baseball tradition. The National League preserves tradition by adhering to the natural law of baseball
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