Covariant Vortex In Superconducting-Superfluid-Normal Fluid Mixtures with Stiff Equation of State

The integrals of motion for a cylindrically symmetric stationary vortex are obtained in a covariant description of a mixture of interacting superconductors, superfluids and normal fluids. The relevant integrated stress-energy coefficients for the vortex with respect to a vortex-free reference state are calculated in the approximation of a ``stiff'', i.e. least compressible, relativistic equation of state for the fluid mixture. As an illustration of the foregoing general results, we discuss their application to some of the well known examples of ``real'' superfluid and superconducting systems that are contained as special cases. These include Landau's two-fluid model, uncharged binary superfluid mixtures, rotating conventional superconductors and the superfluid neutron-proton-electron plasma in the outer core of neutron stars.Comment: 14 pages, uses RevTeX and amssymb, submitte

Structural control on basaltic dike and sill emplacement, Paiute Ridge mafic intrusion complex, southern Nevada

Late Miocene basaltic sills and dikes in the Paiute Ridge area of southern nevada show evidence that their emplacement was structurally controlled. Basaltic dikes in this area formed by dilating pre-existing vertical to steeply E-dipping normal faults. Magma propagation along these faults must have required less energy than the creation of a self-propagated fracture at dike tips and the magma pressure must have been greater than the compressive stress perpendicular to the fault surface. N- to NE-trending en echelon dikes formed locally and are not obviously attached to the three main dikes in the area. The en echelon segments are probably pieces of deeper dikes, which are segmented perhaps as a result of a documented rotation of the regional stresses. Alternatively, changes in orientation of principal stresses in the vicinity of each en echelon dike could have resulted from local loads associated with paleotopographic highs or nearby structures. Sills locally branched off some dikes within 300 m of the paleosurface. These subhorizontal bodies occur consistently in the hanging wall block of the dike-injected faults, and intrude Tertiary tuffs near the Paleozoic-Tertiary contact. The authors suggest that the change in stresses near the earth`s surface, the material strength of the tuff and paleozoic rocks, and the Paleozoic bedding dip direction probably controlled the location of sill formation and direction of sill propagation. The two largest sills deflected the overlying tuffs to form lopoliths, indicating that the magma pressure exceeded vertical stresses at that location and that the shallow level and large size of the sills allowed interaction with the free (earth`s) surface. 32 refs., 4 figs., 1 tab

Seasonal trends in furrow irrigation erosion in southern Idaho

A study was conducted to measure the seasonal irrigation furrow erosion pattern in the absence of cultivation and a growing crop. This erosion pattern was compared to those of previous measured plot experiments for different years in the presence of cultivation and a growing crop. Erosion for sugarbeets, corn and beans was low early in the season and increased to a maximum during the same 3-week period, from 24 June to 10 July over several years. Erosion decreased as the irrigation season progressed after the erosion peak. The erosion pattern from the uncultivated, non-cropped plots resembled the pattern from previous studies on cropped soil with the maximum erosion occurring about the same time of season. The pattern trends differed only after peak erosion. For the cropped plots, there was a sudden erosion decline after peak erosion, followed by a continual gradual decrease. In contrast, for the uncultivated, non-cropped plots, there was a sudden erosion decline after peak erosion, followed by a gradual increase in erosion. Although the seasonal erosion pattern cannot be completely explained, it is important to report it because of the implication for erosion modeling. Sediment loss rates measured from these soils in southern Idaho in late June or early July would significantly overestimate seasonal erosion, whereas sediment loss rates measured in May or early June or after mid-July would underestimate seasonal erosion. These results show that researchers cannot rely upon a one-time measurement for model validation if attempting to predict irrigation furrow erosion over an entire irrigating season

Freezing effects on aggregate stability affected by texture, mineralogy, and organic matter

Aggregate stability, an important property influencing a soil's response to erosive forces, is affected by freezing. The objectives of this laboratory study were to determine how constrainment, number of freeze-thaw cycles, and water content at freezing affect the aggregate stability of six continental USA soils differing in texture, mineralogy, and organic-matter content. Moist aggregates, after being frozen and thawed either zero, one, three, or five times, were vapor wetted to 0.30 kg kg-1 and analyzed by wet sieving. Soils with clay contents of 17% or more and organic-matter contents >3% were the most stable after freezing. Aggregate stability for fine- and medium-textured soils generally decreased linearly with increasing water content at freezing. This linear decrease in stability was more rapid for constrained samples than for unconstrained samples. The stability of field-moist aggregates generally increased from zero to one or three freeze-thaw cycles. For at least one low-organic-matter soil, stability increased from one to three freeze-thaw cycles, but then decreased at five cycles. After thawing, aggregates at water contents of 0.15 kg kg-1 or more that were constrained when frozen were always significantly less stable than aggregates that were unconstrained when frozen

Effects of freezing on aggregate stability of soils differing in texture, mineralogy, and organic matter content

Aggregate stability, a measure of a soil aggregate's resistance to breakdown, influences many soil physical and hydraulic characteristics, such as surface sealing rate, infiltration rate, and hydraulic conductivity. Thus, because aggregate stability is so important, processes that may increase or decrease it should be studied. Different soils have been observed to respond differently to the freezing process. Hence, it was hypothesized that soils differing in texture, mineralogy, and organic matter content would be affected differently. A laboratory experiment was designed to test this hypothesis

Gravitational Collapse of Phantom Fluid in (2+1)-Dimensions

This investigation is devoted to the solutions of Einstein's field equations for a circularly symmetric anisotropic fluid, with kinematic self-similarity of the first kind, in $(2+1)$-dimensional spacetimes. In the case where the radial pressure vanishes, we show that there exists a solution of the equations that represents the gravitational collapse of an anisotropic fluid, and this collapse will eventually form a black hole, even when it is constituted by the phantom energy.Comment: 10 page

Controlling nitrate leaching and erosion on irrigated land

New integrated agronomic cropping systems that nearly eliminate irrigation-induced erosion, significantly reduce nitrate leaching potential, increase crop utilization of nitrogen from legume sources and fertilizer, improve irrigation uniformity, decrease production costs, and increase net profits have resulted from several years of research at Kimberly, Idaho. These systems include growing corn or cereal without tillage following alfalfa to efficiently utilize nitrogen from the legume and reduce irrigation-induced erosion. Where no corn was grown following alfalfa, nitrate-N accumulated up to 550 lbs/ac in the upper 5 feet of soil compared to only 50 lbs/ac where corn was grown. Where beans were grown for two seasons following alfalfa, nitrate-N leaching was 50 lbs/ac more than where corn and then winter wheat were grown. Banding nitrogen fertilizer on the opposite side of the corn row from the irrigation furrow used all season reduced nitrate leaching as compared to where a furrow was irrigated on the same side of the row as the fertilizer band. Nitrate moves below the root zone during wet winters by deep drainage and pass through flow. Polyacrylamide (PAM) concentrations of 10 ppm or less applied into the irrigation water can almost eliminate furrow erosion, and it increases infiltration. Applying cheese whey alone and in combination with straw at whey rates of 12 gallons and straw rates of 4 lbs/100 ft of row before beginning irrigations reduced sediment loss by more than 95%

Gauge fixing and the Hamiltonian for cylindrical spacetimes

We introduce a complete gauge fixing for cylindrical spacetimes in vacuo that, in principle, do not contain the axis of symmetry. By cylindrically symmetric we understand spacetimes that possess two commuting spacelike Killing vectors, one of them rotational and the other one translational. The result of our gauge fixing is a constraint-free model whose phase space has four field-like degrees of freedom and that depends on three constant parameters. Two of these constants determine the global angular momentum and the linear momentum in the axis direction, while the third parameter is related with the behavior of the metric around the axis. We derive the explicit expression of the metric in terms of the physical degrees of freedom, calculate the reduced equations of motion and obtain the Hamiltonian that generates the reduced dynamics. We also find upper and lower bounds for this reduced Hamiltonian that provides the energy per unit length contained in the system. In addition, we show that the reduced formalism constructed is well defined and consistent at least when the linear momentum in the axis direction vanishes. Furthermore, in that case we prove that there exists an infinite number of solutions in which all physical fields are constant both in the surroundings of the axis and at sufficiently large distances from it. If the global angular momentum is different from zero, the isometry group of these solutions is generally not orthogonally transitive. Such solutions generalize the metric of a spinning cosmic string in the region where no closed timelike curves are present.Comment: 12 pages, accepted for publication in Physical Review

Relativistic superfluid models for rotating neutron stars

This article starts by providing an introductory overview of the theoretical mechanics of rotating neutron stars as developped to account for the frequency variations, and particularly the discontinuous glitches, observed in pulsars. The theory suggests, and the observations seem to confirm, that an essential role is played by the interaction between the solid crust and inner layers whose superfluid nature allows them to rotate independently. However many significant details remain to be clarified, even in much studied cases such as the Crab and Vela. The second part of this article is more technical, concentrating on just one of the many physical aspects that needs further development, namely the provision of a satisfactorily relativistic (local but not microscopic) treatment of the effects of the neutron superfluidity that is involved.Comment: 42 pages LateX. Contribution to Physics of Neutron Star Interiors, ed. D. Blasche, N.K. Glendenning, A. Sedrakian (ECT workshop, Trento, June 2000