10,850 research outputs found
Results from the National Aeronautics and Space Administration remote sensing experiments in the New York Bight, 7-17 April 1975
A cooperative operation was conducted in the New York Bight to evaluate the role of remote sensing technology to monitor ocean dumping. Six NASA remote sensing experiments were flown on the C-54, U-2, and C-130 NASA aircraft, while NOAA obtained concurrent sea truth information using helicopters and surface platforms. The experiments included: (1) a Radiometer/Scatterometer (RADSCAT), (2) an Ocean Color Scanner (OCS), (3) a Multichannel Ocean Color Sensor (MOCS), (4) four Hasselblad cameras, (5) an Ebert spectrometer; and (6) a Reconafax IV infrared scanner and a Precision Radiation Thermometer (PRT-5). The results of these experiments relative to the use of remote sensors to detect, quantify, and determine the dispersion of pollutants dumped into the New York Bight are presented
Measuring micro-organism gas production
Transducer, which senses pressure buildup, is easy to assemble and use, and rate of gas produced can be measured automatically and accurately. Method can be used in research, in clinical laboratories, and for environmental pollution studies because of its ability to detect and quantify rapidly the number of gas-producing microorganisms in water, beverages, and clinical samples
WIND-TUNNEL INVESTIGATION AT MACH NUMBERS FROM 0.40 TO 1.20 OF THE STATIC AERODYNAMIC AND CONTROL CHARACTERISTICS OF A MODEL OF A NONLIFTING REENTRY CAPSULE IN COMBINATION WITH A ROCKET BOOSTER
Wind tunnel investigation at subsonic & transonic speed of static aerodynamic and control characteristics of capsule-booster mode
Suppression of spin-pumping by a MgO tunnel-barrier
Spin-pumping generates pure spin currents in normal metals at the ferromagnet
(F)/normal metal (N) interface. The efficiency of spin-pumping is given by the
spin mixing conductance, which depends on N and the F/N interface. We directly
study the spin-pumping through an MgO tunnel-barrier using the inverse spin
Hall effect, which couples spin and charge currents and provides a direct
electrical detection of spin currents in the normal metal. We find that
spin-pumping is suppressed by the tunnel-barrier, which is contrary to recent
studies that suggest that the spin mixing conductance can be enhanced by a
tunnel-barrier inserted at the interface
Detection of fungal damaged popcorn using image property covariance features
Cataloged from PDF version of article.Covariance-matrix-based features were applied to the detection of popcorn infected by a fungus that causes a symptom called "blue-eye". This infection of popcorn kernels causes economic losses due to the kernels' poor appearance and the frequently disagreeable flavor of the popped kernels. Images of kernels were obtained to distinguish damaged from undamaged kernels using image-processing techniques. Features for distinguishing blue-eye-damaged from undamaged popcorn kernel images were extracted from covariance matrices computed using various image pixel properties. The covariance matrices were formed using different property vectors that consisted of the image coordinate values, their intensity values and the first and second derivatives of the vertical and horizontal directions of different color channels. Support Vector Machines (SVM) were used for classification purposes. An overall recognition rate of 96.5% was achieved using these covariance based features. Relatively low false positive values of 2.4% were obtained which is important to reduce economic loss due to healthy kernels being discarded as fungal damaged. The image processing method is not computationally expensive so that it could be implemented in real-time sorting systems to separate damaged popcorn or other grains that have textural differences. (C) 2012 Elsevier B.V. All rights reserve
Inertial range scaling in numerical turbulence with hyperviscosity
Numerical turbulence with hyperviscosity is studied and compared with direct
simulations using ordinary viscosity and data from wind tunnel experiments. It
is shown that the inertial range scaling is similar in all three cases.
Furthermore, the bottleneck effect is approximately equally broad (about one
order of magnitude) in these cases and only its height is increased in the
hyperviscous case--presumably as a consequence of the steeper decent of the
spectrum in the hyperviscous subrange. The mean normalized dissipation rate is
found to be in agreement with both wind tunnel experiments and direct
simulations. The structure function exponents agree with the She-Leveque model.
Decaying turbulence with hyperviscosity still gives the usual t^{-1.25} decay
law for the kinetic energy, and also the bottleneck effect is still present and
about equally strong.Comment: Final version (7 pages
Detection and quantification of inverse spin Hall effect from spin pumping in permalloy/normal metal bilayers
Spin pumping is a mechanism that generates spin currents from ferromagnetic
resonance (FMR) over macroscopic interfacial areas, thereby enabling sensitive
detection of the inverse spin Hall effect that transforms spin into charge
currents in non-magnetic conductors. Here we study the spin-pumping-induced
voltages due to the inverse spin Hall effect in permalloy/normal metal bilayers
integrated into coplanar waveguides for different normal metals and as a
function of angle of the applied magnetic field direction, as well as microwave
frequency and power. We find good agreement between experimental data and a
theoretical model that includes contributions from anisotropic
magnetoresistance (AMR) and inverse spin Hall effect (ISHE). The analysis
provides consistent results over a wide range of experimental conditions as
long as the precise magnetization trajectory is taken into account. The spin
Hall angles for Pt, Pd, Au and Mo were determined with high precision to be
, , and ,
respectively.Comment: 11 page
The connection between the 15 GHz radio and gamma-ray emission in blazars
Since mid-2007 we have carried out a dedicated long-term monitoring programme
at 15 GHz using the Owens Valley Radio Observatory 40 meter telescope. One of
the main goals of this programme is to study the relation between the radio and
gamma-ray emission in blazars and to use it as a tool to locate the site of
high energy emission. Using this large sample of objects we are able to
characterize the radio variability, and study the significance of correlations
between the radio and gamma-ray bands. We find that the radio variability of
many sources can be described using a simple power law power spectral density,
and that when taking into account the red-noise characteristics of the light
curves, cases with significant correlation are rare. We note that while
significant correlations are found in few individual objects, radio variations
are most often delayed with respect to the gamma-ray variations. This suggests
that the gamma-ray emission originates upstream of the radio emission. Because
strong flares in most known gamma-ray-loud blazars are infrequent, longer light
curves are required to settle the issue of the strength of radio-gamma
cross-correlations and establish confidently possible delays between the two.
For this reason continuous multiwavelength monitoring over a longer time period
is essential for statistical tests of jet emission models.Comment: To appear in the Proceedings of the IAU Symposium No. 313:
"Extragalactic jets from every angle," Galapagos, Ecuador, 15-19 September
2014, F. Massaro, C. C. Cheung, E. Lopez, and A. Siemiginowska (Eds.),
Cambridge University Pres
- …