8,010 research outputs found
The use of geomagnetic field models in magnetic surveys
The importance of global geomagnetic field models for the reduction of magnetic surveys is discussed. It is demonstrated that a numerical model with adequate secular variation correction, provides a suitable representation of the regional field. The limitations of the presently available models are reported, with emphasis on the International Geomagnetic Reference Field
Adverse events following influenza immunization reported by healthcare personnel using active surveillance based on text messages
Studies have demonstrated that healthcare personnel (HCP) have concerns about the potential side effects of trivalent inactivate influenza vaccine (IIV3).1-3 A recent metaanalysis of reasons HCP refuse IIV3 indicates the strongest predictors of vaccine acceptance are belief that the vaccine is safe and belief the vaccine does not cause the disease it is meant to prevent.
Cosmic String Power Spectrum, Bispectrum and Trispectrum
We use analytic calculations of the post-recombination gravitational effects
of cosmic strings to estimate the resulting CMB power spectrum, bispectrum and
trispectrum. We place a particular emphasis on multipole regimes relevant for
forthcoming CMB experiments, notably the Planck satellite. These calculations
use a flat sky approximation, generalising previous work by integrating string
contributions from last scattering to the present day, finding the dominant
contributions to the correlators for multipoles l > 50. We find a well-behaved
shape for the string bispectrum (without divergences) which is easily
distinguishable from the inflationary bispectra which possess significant
acoustic peaks. We estimate that the nonlinearity parameter characterising the
bispectrum is approximately f_NL \sim -20 (given present string constraints
from the CMB power spectrum. We also apply these unequal time correlator
methods to calculate the trispectrum for parrallelogram configurations, again
valid over a large range of angular scales relevant for WMAP and Planck, as
well as on very small angular scales. We find that, unlike the bispectrum which
is suppressed by symmetry considerations, the trispectrum for cosmic strings is
large. Our current estimate for the trispectrum parameter is tau_NL \sim 10^5,
which may provide one of the strongest constraints on the string model as
estimators for the trispectrum are developed
In-Flight Stability Analysis of the X-48B Aircraft
This report presents the system description, methods, and sample results of the in-flight stability analysis for the X-48B, Blended Wing Body Low-Speed Vehicle. The X-48B vehicle is a dynamically scaled, remotely piloted vehicle developed to investigate the low-speed control characteristics of a full-scale blended wing body. Initial envelope clearance was conducted by analyzing the stability margin estimation resulting from the rigid aircraft response during flight and comparing it to simulation data. Short duration multisine signals were commanded onboard to simultaneously excite the primary rigid body axes. In-flight stability analysis has proven to be a critical component of the initial envelope expansion
Renovation of Nitrogenous Wastewater Via Land Application
Removal of inorganic and organic nitrogen from wastewater prior to recharge of ground and surface waters can be accomplished by judicious land application. This study focused attention upon the feasibility of using sprinkler irrigation as the wastewater delivery system with coastal bermudagrass (Cynodon dactylon L.,var. coastal) pasture as the wastewater sink. One site was located on a Sawyer soil near El Dorado, while the other was located on a Savannah soil near Malvern. This report is limited to the renovation of surface waters. Results revealed that nitrogen concentration in runoff water from rainfall was substantially less than nitrogen concentration of the wastewater applied to the soil and similar to background levels. Such results support the consideration of land application as a viable wastewater disposal method
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