The effects of pressure on the biodegradability of sanitary sewage in a model activated sludge reactor

Based on existing information concerning the effects of pressure on the biodegradability of sanitary sewage, a model activated sludge reactor was used in conjunction with pressurization to determine the viability of pressurization as a primary sewage treatment process. Municipal sewage samples were pressurized at 40 psig for one hour with an excess of oxygen. An air compressor and a steel drum were used for sample pressurization. A non-pressurized control sample was maintained. After pressurization, the samples were fed into separate model activated sludge reactors. Biodegradability of both types of effluent was measured by determining their five day biochemical oxygen demands (B.O.D.). Other tests were performed on the samples to measure turbidity, ammonia content, and long term B.O.D. It was found that after treatment in the reactor, no definitive measured effect due to pressurization was observed in the five day B.O.D. test. However, the pressurized effluent was found to be more turbid, and to have a higher ammonia content than the non-pressurized sample. The long term B.O.D. tests indicated some divergence between the pressurized and non-pressurized effluent B.O.D. curves

Momentum-resolved electron-phonon interaction in lead determined by neutron resonance spin-echo spectroscopy

Neutron resonance spin-echo spectroscopy was used to monitor the temperature evolution of the linewidths of transverse acoustic phonons in lead across the superconducting transition temperature, $T_c$, over an extended range of the Brillouin zone. For phonons with energies below the superconducting energy gap, a linewidth reduction of maximum amplitude $\sim 6 \mu$eV was observed below $T_c$. The electron-phonon contribution to the phonon lifetime extracted from these data is in satisfactory overall agreement with {\it ab-initio} lattice-dynamical calculations, but significant deviations are found

Landau damping of Bogoliubov excitations in optical lattices at finite temperature

We study the damping of Bogoliubov excitations in an optical lattice at finite temperatures. For simplicity, we consider a Bose-Hubbard tight-binding model and limit our analysis to the lowest excitation band. We use the Popov approximation to calculate the temperature dependence of the number of condensate atoms $n^{\rm c 0}(T)$ in each lattice well. We calculate the Landau damping of a Bogoliubov excitation in an optical lattice due to coupling to a thermal cloud of excitations. While most of the paper concentrates on 1D optical lattices, we also briefly present results for 2D and 3D lattices. For energy conservation to be satisfied, we find that the excitations in the collision process must exhibit anomalous dispersion ({\it i.e.} the excitation energy must bend upward at low momentum), as also exhibited by phonons in superfluid $^4\rm{He}$. This leads to the sudden disappearance of all damping processes in $D$-dimensional simple cubic optical lattice when $U n^{\rm c 0}\ge 6DJ$, where $U$ is the on-site interaction, and $J$ is the hopping matrix element. Beliaev damping in a 1D optical lattice is briefly discussed.Comment: 28 pages, 9 figure

Quantum phase transitions in holographic models of magnetism and superconductors

We study a holographic model realizing an "antiferromagnetic" phase in which a global SU(2) symmetry representing spin is broken down to a U(1) by the presence of a finite electric charge density. This involves the condensation of a neutral scalar field in a charged AdS black hole. We observe that the phase transition for both neutral and charged (as in the standard holographic superconductor) order parameters can be driven to zero temperature by a tuning of the UV conformal dimension of the order parameter, resulting in a quantum phase transition of the Berezinskii-Kosterlitz-Thouless type. We also characterize the antiferromagnetic phase and an externally forced ferromagnetic phase by showing that they contain the expected spin waves with linear and quadratic dispersions respectively.Comment: 24 pages; v2: references added, typos correcte

Interrelations Between the Neutron's Magnetic Interactions and the Magnetic Aharonov-Bohm Effect

It is proved that the phase shift of a polarized neutron interacting with a spatially uniform time-dependent magnetic field, demonstrates the same physical principles as the magnetic Aharonov-Bohm effect. The crucial role of inert objects is explained, thereby proving the quantum mechanical nature of the effect. It is also proved that the nonsimply connectedness of the field-free region is not a profound property of the system and that it cannot be regarded as a sufficient condition for a nonzero phase shift.Comment: 18 pages, 1 postscript figure, Late

Accumulation of three-body resonances above two-body thresholds

We calculate resonances in three-body systems with attractive Coulomb potentials by solving the homogeneous Faddeev-Merkuriev integral equations for complex energies. The equations are solved by using the Coulomb-Sturmian separable expansion approach. This approach provides an exact treatment of the threshold behavior of the three-body Coulombic systems. We considered the negative positronium ion and, besides locating all the previously know $S$-wave resonances, we found a whole bunch of new resonances accumulated just slightly above the two-body thresholds. The way they accumulate indicates that probably there are infinitely many resonances just above the two-body thresholds, and this might be a general property of three-body systems with attractive Coulomb potentials.Comment: 4 pages, 3 figure

Population dynamics of Azotobacter chroococcum in sugarbeet rhizosphere depending on mineral nutrition

Population dynamics of Azotobacter chroococcum has been studied in the rhizosphere of a sugarbeet hybrid inoculated with Azotobacter strains 5, 8 and 14. Simultaneously we examined the effects of four levels of nitrogen fertilization (non-fertilized control, 50, 100, 150 and 200 kg N/ha) and the applications of manure and harvest residues. Samples were taken three times in May, July and October. The experiment included inoculated and non-inoculated variants at all four levels of fertilization, in five replicates

Characterization of a ballistic supermirror neutron guide

We describe the beam characteristics of the first ballistic supermirror neutron guide H113 that feeds the neutron user facility for particle physics PF1B of the Institute Laue-Langevin, Grenoble (ILL). At present, the neutron capture flux density of H113 at its 20x6cm2 exit window is 1.35x10^10/cm^2/s, and will soon be raised to above 2x10^10/cm^2/s. Beam divergence is no larger than beam divergence from a conventional Ni coated guide. A model is developed that permits rapid calculation of beam profiles and absolute event rates from such a beam. We propose a procedure that permits inter-comparability of the main features of beams emitted from ballistic or conventional neutron guides.Comment: 15 pages, 11 figures, to be submitted to Nuclear Instruments and Methods