Advanced bearing study. Part 2: Bearing tests

Tests of ball bearings of various material combinations in liquid hydroge

Nitrogen removal during summer and winter in a primary facultative WSP pond: preliminary findings from 15N-labelled ammonium tracking techniques

Nitrogen removal mechanisms and pathways within WSP have been the focus of much research over the last 30 years. Debates and theories postulated continue to refine our knowledge regarding the cycling and removal pathways for this important nutrient, but a succinct answer has yet to be provided for holistic nitrogen removal. In this study, two experimental runs using labelled 15N as a stable isotope tracking technique were conducted on a pilot-scale primary facultative WSP in the UK; one in the summer of 2006, and the other in the winter of 2007. An ammonium chloride (15NH4Cl) spike was prepared as the slug for each experimental run, which also contained rhodamine WT to act as a dye tracer enabling the hydraulic characteristics of the pond to be mapped. Initial results from the study are reported here, and findings are compared and contrasted. Preliminary findings reveal that a greater proportion of 15N is incorporated into the algal biomass by assimilation and subsequent release as soluble organic nitrogen in summer than in winter. 15N ammonium passes out of the system much sooner and in a much higher proportion in the winter than in summer

Rangeland biomass estimation demonstration

Because of their sensitivity to chlorophyll density, green leaf density, and leaf water density, two hand-held radiometers which have sensor bands coinciding with thematic mapper bands 3, 4, and 5 were used to calibrate green biomass to LANDSAT spectral ratios as a step towards using portable radiometers to speed up ground data acquisition. Two field reflectance panels monitored incoming radiation concurrently with sampling. Software routines were developed and used to extract data from uncorrected tapes of MSS data provided in NASA LANDSAT universal format. A LANDSAT biomass calibration curve estimated the range biomass over a four scene area and displayed this information spatially as a product in a format of use to ranchers. The regional biomass contour map is discussed

Surveying the solar system by measuring angles and times: from the solar density to the gravitational constant

A surprisingly large amount of information on our solar system can be gained from simple measurements of the apparent angular diameters of the sun and the moon. This information includes the average density of the sun, the distance between earth and moon, the radius of the moon, and the gravitational constant. In this note it is described how these and other quantities can be obtained by simple earthbound measurements of angles and times only, without using any explicit information on distances between celestial bodies. The pedagogical and historical aspects of these results are also discussed briefly.Comment: 12 pges, one figur

Use of the tensor product for numerical weather prediction by the finite element method

This is Part 2 of a report-pair concerning application of the tensor product in solving large sets of simultaneous linear equations arising in finite element formulations of Numerical Weather Prediction problems. A rectangular region having a graded mesh with Dirichlet boundary conditions on all four edges is considered. Coefficient matrices are the "mass" matrix and the "stiffness" matrix of the finite element method. For the stiffness matrix, which appears in Poisson's equation, operation counts and storage requirements are compared with corresponding numbers for solutions by successive over-relaxation and Gaussian elimination. FORTRAN programs for implementation of the tensor product formulations are given.Naval Environmental Prediction Research Facility, Monterey, Californiahttp://archive.org/details/useoftensorprodu005new

Levinson's theorem for the Schr\"{o}dinger equation in two dimensions

Levinson's theorem for the Schr\"{o}dinger equation with a cylindrically symmetric potential in two dimensions is re-established by the Sturm-Liouville theorem. The critical case, where the Schr\"{o}dinger equation has a finite zero-energy solution, is analyzed in detail. It is shown that, in comparison with Levinson's theorem in non-critical case, the half bound state for $P$ wave, in which the wave function for the zero-energy solution does not decay fast enough at infinity to be square integrable, will cause the phase shift of $P$ wave at zero energy to increase an additional $\pi$.Comment: Latex 11 pages, no figure and accepted by P.R.A (in August); Email: [email protected], [email protected]

Generalized Mean Field Approach to a Resonant Bose-Fermi Mixture

We formulate a generalized mean-field theory of a mixture of fermionic and bosonic atoms, in which the fermion-boson interaction can be controlled by a Feshbach resonance. The theory correctly accounts for molecular binding energies of the molecules in the two-body limit, in contrast to the most straightforward mean-field theory. Using this theory, we discuss the equilibrium properties of fermionic molecules created from atom pairs in the gas. We also address the formation of molecules when the magnetic field is ramped across the resonance, and present a simple Landau-Zener result for this process.Comment: 35 page

Deep sea photography

Interest of the senior author in deep sea photography stems from a desire to obtain photographs of deep sea luminous fish-not by their own light, but in their natural environment, using artificial illumination. The abundance of deep sea forms observed by Beebe (1934) from his bathysphere suggests that success might be achieved, especiaJly if a lure could be found that would attract deep sea fish to the front of the camera

On the Localization of One-Photon States

Single photon states with arbitrarily fast asymptotic power-law fall-off of energy density and photodetection rate are explicitly constructed. This goes beyond the recently discovered tenth power-law of the Hellwarth-Nouchi photon which itself superseded the long-standing seventh power-law of the Amrein photon.Comment: 7 pages, tex, no figure

ECONOMIC AND ENVIRONMENTAL EVALUATION OF DAIRY MANURE UTILIZATION FOR YEAR ROUND CROP PRODUCTION

The production of excess on-farm manure is placing continuous pressures on dairy producers to meet or exceed standards for environmental regulations while maintaining profitability and competitiveness. Evaluation of the effects of recycling nutrients on the profitability of the whole farm enterprise is important for a dairy operation. The objective of this study was to develop a linear programming model that evaluates the economic performance of a dairy operation considering production and environmental constraints. The main goal was to maximize profits from the dairy enterprise considering milk production, manure production, crop production while maintaining a balance of nutrients in the system. Results from simulation analyses showed greater effects on total farm profits at the more restrictive P-based than N-based manure application rates.Environmental Economics and Policy,