33,795 research outputs found
Hydrogeological and Hydrochemical Connection Between the Decatur City Spring and Crystal Lake, Benton County, Arkansas
Arkansas is ranked nationally in the production of broilers, laying hens, turkey, swine and beef cattle. These animals produce large volumes of waste, which are spread on pasture land as a method of disposal, as well as a source of fertilizer, resulting in nonpoint source contamination of surface water and ground water. One area of concern includes the Decatur City Spring, which provides municipal water for the city of Decatur. A total of eight sites in the surrounding area were monitored routinely for water quality parameters, including pH, specific conductance, and nitrate-nitrogen. Water temperature and spring and lake stage were also recorded. Crystal Lake (site 7), an impoundment of Wolf Creek (site 4) is south and upstream from the Decatur City Spring (site 3). It has been proposed that the city spring and lake are hydrogeologically connected. Additionally, there are two springs, (sites 5 and 6) both northwest and downstream of the lake, below the dam, that provide most of the flow to Wolf Creek. Spring site 1 is downstream from Decatur City Spring on Wolf Creek. Results indicate relatively low, but consistent nitrate concentrations for sites 7 (0.7-1.4 mg/L), 5 (0.4-1.0 mg/L) and 6 (0.2-0.6 mg/L), which are the lake and two springs below it, respectively. These consistent concentrations, as well as the similar periodicities, suggest an association between these three sites. Higher nitrate concentrations are exhibited for sites 3 (2.4-3.0 mg/L) and 1 (2.4-2.9 mg/L), which are the city spring and the spring north of it. There is also correlation in the periodicity of these two sites indicating a relationship between them. Based on similar fluctuations in the hydrochemical data, it can be concluded that Crystal Lake and Decatur Spring are hydrogeologically related. Water flows from Crystal Lake to the two springs below the dam. These springs feed Wolf Creek which is then connected to Decatur Spring via a losing segment just above the spring, hydrogeologically connecting Decatur Spring to Crystal Lake
Poynting Vector Flow in a Circular Circuit
A circuit is considered in the shape of a ring, with a battery of negligible
size and a wire of uniform resistance. A linear charge distribution along the
wire maintains an electrostatic field and a steady current, which produces a
constant magnetic field. Earlier studies of the Poynting vector and the rate of
flow of energy considered only idealized geometries in which the Poynting
vector was confined to the space within the circuit. But in more realistic
cases the Poynting vector is nonzero outside as well as inside the circuit. An
expression is obtained for the Poynting vector in terms of products of
integrals, which are evaluated numerically to show the energy flow. Limiting
expressions are obtained analytically. It is shown that the total power
generated by the battery equals the energy flowing into the wire per unit time.Comment: 19 pages, 8 figure
Probing the classical field approximation - thermodynamics and decaying vortices
We review our version of the classical field approximation to the dynamics of
a finite temperature Bose gas. In the case of a periodic box potential, we
investigate the role of the high momentum cut-off, essential in the method. In
particular, we show that the cut-off going to infinity limit decribes the
particle number going to infinity with the scattering length going to zero. In
this weak interaction limit, the relative population of the condensate tends to
unity. We also show that the cross-over energy, at which the probability
distribution of the condensate occupation changes its character, grows with a
growing scattering length. In the more physical case of the condensate in the
harmonic trap we investigate the dissipative dynamics of a vortex. We compare
the decay time and the velocities of the vortex with the available analytic
estimates.Comment: 7 pages, 8 eps figures, submitted to J. Optics B for the proceedings
of the "Atom Optics and Interferometry" Lunteren 2002 worksho
Earth feature identification for onboard multispectral data editing: Computational experiments
A computational model of the processes involved in multispectral remote sensing and data classification is developed as a tool for designing smart sensors which can process, edit, and classify the data that they acquire. An evaluation of sensor system performance and design tradeoffs involves classification rates and errors as a function of number and location of spectral channels, radiometric sensitivity and calibration accuracy, target discrimination assignments, and accuracy and frequency of compensation for imaging conditions. This model provides a link between the radiometric and statistical properties of the signals to be classified and the performance characteristics of electro-optical sensors and data processing devices. Preliminary computational results are presented which illustrate the editing performance of several remote sensing approaches
Dissipative dynamics of vortex arrays in trapped Bose-condensed gases: neutron stars physics on K scale
We develop a theory of dissipative dynamics of large vortex arrays in trapped
Bose-condensed gases. We show that in a static trap the interaction of the
vortex array with thermal excitations leads to a non-exponential decay of the
vortex structure, and the characteristic lifetime depends on the initial
density of vortices. Drawing an analogy with physics of pulsar glitches, we
propose an experiment which employs the heating of the thermal cloud in the
course of the decay of the vortex array as a tool for a non-destructive study
of the vortex dynamics.Comment: 4 pages, revtex; revised versio
Simulations of thermal Bose fields in the classical limit
We demonstrate that the time-dependent projected Gross-Pitaevskii equation
derived earlier [Davis, et al., J. Phys. B 34, 4487 (2001)] can represent the
highly occupied modes of a homogeneous, partially-condensed Bose gas. We find
that this equation will evolve randomised initial wave functions to
equilibrium, and compare our numerical data to the predictions of a gapless,
second-order theory of Bose-Einstein condensation [S. A. Morgan, J. Phys. B 33,
3847 (2000)]. We find that we can determine the temperature of the equilibrium
state when this theory is valid.
Outside the range of perturbation theory we describe how to measure the
temperature of our simulations. We also determine the dependence of the
condensate fraction and specific heat on temperature for several interaction
strengths, and observe the appearance of vortex networks. As the
Gross-Pitaevskii equation is non-perturbative, we expect that it can describe
the correct thermal behaviour of a Bose gas as long as all relevant modes are
highly occupied.Comment: 15 pages, 12 figures, revtex4, follow up to Phys. Rev. Lett. 87
160402 (2001). v2: Modified after referee comments. Extra data added to two
figures, section on temperature determination expande
Quantum whistling in superfluid 4He
Fundamental considerations predict that macroscopic quantum systems such as
superfluids and the electrons in superconductors will exhibit oscillatory
motion when pushed through a small constriction. Here we report the observation
of these oscillations between two reservoirs of superfluid 4He partitioned by
an array of nanometer-sized apertures. They obey the Josephson frequency
equation and are coherent amongst all the apertures. This discovery at the
relatively high temperature of 2K (2000 times higher than related phenomena in
3He) may pave the way for a new class of practical rotation sensors of
unprecedented precision.Comment: 6 pages, 3 figures, to be published in Natur
First report on incidence of inflorescence blight and pod rot (Choanephora infundibulifera) on dolichos bean (Dolichos lablab, L.) and yard long beanin (Vignaunguiculata sub sp. sesquipedalis) India
Inflorescence blight and pod rot caused by Choanephorasp. were recorded in two major vegetable crops viz.dolichos bean and yard long bean at a very high degree of severity. Usually, the disease occurs in mild proportions without causing economic loss during rainy season in Kerala (June to September) affecting vegetable crops like cowpea and bhendi. However, during the year 2016, the disease was noticed with a very high severity of more than 90 per cent on two crops grown at two different locations in Thrissur district of Kerala during October to January. None of the commonly used fungicides could control the disease. The pathogen was found to be luxuriantly growing on the inflorescences of dolichos bean and on the fruits of yard long bean. The first incidence of the disease was recorded during the last week of October, 2016. The disease spread was almost cent per cent on susceptible genotypes of dolichos bean and more than 90 per cent in variety ‘Vaijayanthi’ of yard long bean. A study was conducted exploring the pre disposing factors leading to the occurrence of the disease in epidemic proportions.Meteorological factors affecting the disease were studied and it was found that there is positive correlation of the disease severity with increasing atmospheric temperature and rainfall.Atmospheric temperature more than 30oC along with high humidity and rain fall during the preceding week are found to be the major pre disposing factors lead to the epidemic in both the crops. The pathogen was isolated and based on morphological characters, identified as Choanephora sp. Pathogenicity was proved by inoculation on healthy inflorescence stalks.Molecular characterization of the pathogen confirmed the identity as Choanephora infundibulifera. This is the first report of the pathogen on dolichos bean and yard long bean in India
Brane Cosmology Solutions with Bulk Scalar Fields
Brane cosmologies with static, five-dimensional and Z_2 symmetric bulks are
analysed. A general solution generating mechanism is outlined. The qualatitive
cosmological behaviour of all such solutions is determined. Conditions for
avoiding naked bulk singularities are also discussed. The restrictions placed
on the solutions by the assumption of such a static bulk are investigated. In
particular the requirement of a non-standard energy-momentum conservation law.
The failure of such solutions to provide viable quintessence terms in the
Friedmann equations is also discussed.Comment: 15 pages, references added, minor change
Mutual information between geomagnetic indices and the solar wind as seen by WIND : implications for propagation time estimates
The determination of delay times of solar wind conditions at the sunward libration point to effects on Earth is investigated using mutual information. This measures the amount of information shared between two timeseries. We consider the mutual information content of solar wind observations, from WIND, and the geomagnetic indices. The success of five commonly used schemes for estimating interplanetary propagation times is examined. Propagation assuming a fixed plane normal at 45 degrees to the GSE x-axis (i.e. the Parker Spiral estimate) is found to give optimal mutual information. The mutual information depends on the point in space chosen as the target for the propagation estimate, and we find that it is maximized by choosing a point in the nightside rather than dayside magnetosphere. In addition, we employ recurrence plot analysis to visualize contributions to the mutual information, this suggests that it appears on timescales of hours rather than minutes
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