59,169 research outputs found
Evaluation of Sampling Strategies on Load Estimation For Illinois River at Highway 59
This study investigated the precision and accuracy of the two load calculation techniques. The study compared total phosphorus loads calculated by integration of Arkansas Water Resources Center (AWRC) intensive sampling data to loads calculated by a regression technique (rating curve) using fewer data. The 1998 AWRC dataset from the Illinois River at Arkansas Highway 59 was sub-sampled in a manner to simulate fixed period monitoring schemes supplemented with storm sampling. The ESTIMATOR software program was used to calculate loads. These loads were compared to the integrated load. The error of the integrated load when the variation in concentration between samples is not linear and the sensitivity of the integrated load to sampling interval were also investigated. The results show that the central tendency of the ESTIMATOR loads is accurate when storm data are included, but that the 95% confidence interval represents up to +/- 30-40% difference from the integrated load for individual estimates. More frequent sampling and more samples lead to more accurate loads. The results indicate that the central tendency of load estimates would be accurate for a method that uses a regression model with 32 or more samples including storm samples
Method for deducing anisotropic spin-exchange rates
Using measured spin-transfer rates from alkali atoms to He-3, combined with
spin-relaxation rates of the alkali atoms due to He-3 and He-4, it should be
possible to differentiate between isotropic and anisotropic spin-exchange. This
would give a fundamental limit on the He-3 polarization attainable in
spin-exchange optical pumping. For K-He, we find the limit to be 0.90+-0.11
Three Numerical Puzzles and the Top Quark's Chiral Weak-Moment
Versus the standard model's t --> W b decay helicity amplitudes, three
numerical puzzles occur at the 0.1 % level when one considers the amplitudes in
the case of an additional (f_M + f_E) coupling of relative strength 53 GeV. The
puzzles are theoretical ones which involve the t --> W b decay helicity
amplitudes in the two cases, the relative strength of this additional coupling,
and the observed masses of these three particles. A deeper analytic realization
is obtained for two of them. Equivalent realizations are given for the
remaining one. An empirical consequence of these analytic realizations is that
it is important to search for effects of a large chiral weak-moment of the
top-quark, the effective mass-scale is about 53 GeV. A full theoretical
resolution would include relating the origin of such a chiral weak-moment and
the mass generation of the top-quark, the W-boson, and probably the b-quark.Comment: 18 pages, 1 postscript table (revised to better explain notation,
model #1, add a little material...
Phenomenology of loop quantum cosmology
After introducing the basic ingredients of Loop Quantum Cosmology, I will
briefly discuss some of its phenomenological aspects. Those can give some
useful insight about the full Loop Quantum Gravity theory and provide an answer
to some long-standing questions in early universe cosmology.Comment: 16 pages, 3 figures; Invited talk in the First Mediterranean
Conference on Classical and Quantum Gravity (Crete, Greece
Application of Remote Sensing Techniques for Appraising Changes in Wildlife Habitat
An attempt was made to investigate the potential of airborne, multispectral, line scanner data acquisition and computer-implemented automatic recognition techniques for providing useful information about waterfowl breeding habitat in North Dakota. The spectral characteristics of the components of a landscape containing waterfowl habitat can be detected with airborne scanners. By analyzing these spectral characteristics it is possible to identify and map the landscape components through analog and digital processing methods. At the present stage of development multispectral remote sensing techniques are not ready for operational application to surveys of migratory bird habitat and other such resources. Further developments are needed to: (1) increase accuracy; (2) decrease retrieval and processing time; and (3) reduce costs
AMTV headway sensor and safety design
A headway sensing system for an automated mixed traffic vehicle (AMTV) employing an array of optical proximity sensor elements is described, and its performance is presented in terms of object detection profiles. The problem of sensing in turns is explored experimentally and requirements for future turn sensors are discussed. A recommended headway sensor configuration, employing multiple source elements in the focal plane of one lens operating together with a similar detector unit, is described. Alternative concepts including laser radar, ultrasonic sensing, imaging techniques, and radar are compared to the present proximity sensor approach. Design concepts for an AMTV body which will minimize the probability of injury to pedestrians or passengers in the event of a collision are presented
Analysis of webs of partial-tension-field beams subjected to lateral pressure loadings
Webs of partial-tension-field beams subjected to lateral pressure loading
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