12,163 research outputs found
Science leadership for tomorrow: The role of schools of public affairs and universities in meeting needs of public science agencies
Recommendations and requirements for the preparation of personnel with some scientific or technological background to enter fields of public policy and administration are reported. University efforts to provide science administration graduate programs are outlined and increased cooperation between government and university resources is outlined
Performance of charge-injection-device infrared detector arrays at low and moderate backgrounds
Three 2 x 64 element charge injection device infrared detector arrays were tested at low and moderate background to evaluate their usefulness for space based astronomical observations. Testing was conducted both in the laboratory and in ground based telescope observations. The devices showed an average readout noise level below 200 equivalent electrons, a peak responsivity of 4 A/W, and a noise equivalent power of 3x10 sq root of W/Hz. Array well capacity was measured to be significantly smaller than predicted. The measured sensitivity, which compares well with that of nonintegrating discrete extrinsic silicon photoconductors, shows these arrays to be useful for certain astronomical observations. However, the measured readout efficiency and frequency response represent serious limitations in low background applications
Germination and storage of apple seeds
Apple seeds will not germinate immediately after the fruit has become mature enough for picking. It is necessary for the seed to pass thru a stage of after-ripening.
The freshly extracted apple seed contains about 85 percent moisture. At room temperature approximately one-half of the moisture is lost during the first five days.
Soaking the seed prior to planting does not increase germination.
Ninety-one percent of apple seeds prevented from drying out when they were extracted from the fruit germinated. The best temperature for storage was found to be a temperature between 10 and 30 C. Seeds which had air dried germinated poorly in all cases.
Apple seeds which had been air dried and kept for a year did not germinate.
Apple seeds may be planted any time after Nov. 1. Where seeds are to be shipped long distances, special precaution must be made to keep the seeds from deteriorating.
The seed coat is not a factor in causing delayed germination
Addemdum to: ''The Mathematical Structure of Quantum Superspace as a Consequence of Time Asymmetry''
In this paper we improve the results of sec. VI of paper [M. Castagnino,
Phys. Rev. D 57, 750 (1998)] by considering that the main source of entropy
production are the photospheres of the stars
Classical and quantum regimes of two-dimensional turbulence in trapped Bose-Einstein condensates
We investigate two-dimensional turbulence in finite-temperature trapped
Bose-Einstein condensates within damped Gross-Pitaevskii theory. Turbulence is
produced via circular motion of a Gaussian potential barrier stirring the
condensate. We systematically explore a range of stirring parameters and
identify three regimes, characterized by the injection of distinct quantum
vortex structures into the condensate: (A) periodic vortex dipole injection,
(B) irregular injection of a mixture of vortex dipoles and co-rotating vortex
clusters, and (C) continuous injection of oblique solitons that decay into
vortex dipoles. Spectral analysis of the kinetic energy associated with
vortices reveals that regime (B) can intermittently exhibit a Kolmogorov
power law over almost a decade of length or wavenumber () scales.
The kinetic energy spectrum of regime (C) exhibits a clear power law
associated with an inertial range for weak-wave turbulence, and a
power law for high wavenumbers. We thus identify distinct regimes of forcing
for generating either two-dimensional quantum turbulence or classical weak-wave
turbulence that may be realizable experimentally.Comment: 11 pages, 10 figures. Minor updates to text and figures 1, 2 and
Effects of flame retardance additives on the mechanical and fire performance of natural fibre composites
The incorporation of sustainability is becoming increasingly important in manufacturing practices worldwide. This includes the development of natural fibre composites with mechanical and flammability characteristics suitable for structural interiors. Composites manufactured from kenaf fibres and polypropylene (PP) were investigated as to their suitability as materials for the interiors of buildings, aircraft and such-like. Natural fibres like kenaf act as fuel sources during combustion, and hence, flame retardants are added to the mix. In the present study, the ammonium polyphosphate (APP)-based flame retardant Budit® 3167 was used to address this issue. Limited studies exist on how the inclusion of APP influences the composites’ mechanical properties. Hence the main objective of this research project was to evaluate the effect of adding Budit 3167 on both mechanical and flammability properties of kenaf-PP composites. Kenaf-PP composites were manufactured with various fibre weight percentages, with and without Budit 3167. The composites were subjected to different experiments to assess their mechanical and flammability behaviour. It was found that Budit 3167 not only improved the flammability properties of the composites, but also the tensile and flexural moduli due to the flame retardant behaving like a particle reinforcement. However, weak interfacial bonds arising from the addition of Budit 3167 led to a decrease in mechanical strength, providing a basis for further investigation. It was concluded that kenafPP composites with Budit 3167 show good potential as a sustainable alternative for structural interiors
The Suzaku Observation of NGC 3516: Complex Absorption and the Broad and Narrow Fe K Lines
We present results from a 150 ksec Suzaku observation of the Seyfert 1.5 NGC
3516 in October 2005. The source was in a relatively highly absorbed state. Our
best-fit model is consistent with the presence of a low-ionization absorber
which has a column density near 5 * 10^{22} cm^{-2} and covers most of the
X-ray continuum source (covering fraction 96-100%). A high-ionization absorbing
component, which yields a narrow absorption feature consistent with Fe K XXVI,
is confirmed. A relativistically broadened Fe K alpha line is required in all
fits, even after the complex absorption is taken into account; an additional
partial-covering component is an inadequate substitute for the continuum
curvature associated with the broad Fe line. A narrow Fe K alpha emission line
has a velocity width consistent with the Broad Line Region. The low-ionization
absorber may be responsible for producing the narrow Fe K alpha line, though a
contribution from additional material out of the line of sight is possible. We
include in our model soft band emission lines from He- and H-like ions of N, O,
Ne and Mg, consistent with photo-ionization, though a small contribution from
collisionally-ionized emission is possible.Comment: Accepted for publication in PASJ (Suzaku second special issue). 36
pages, 10 figure
Recommended cereal varieties : 1969
Cereal varieties widely recommended for growing in 1969 are Gamenya and Falcon wheats, Dampier and Beecher barleys and Swan oats.
Other varieties include the new wheat Darkan, which is recommended only for the higher rainfall areas, the rust resistant wheats Mengavi and Gamut, and Irwin oats for late sowing in northeastern districts
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