Self-consistent equilibrium of a two-dimensional electron system with a reservoir in a quantizing magnetic field: Analytical approach

An analytical approach has been developed to describe grand canonical equilibrium between a three dimensional (3D) electron system and a two dimensional (2D) one, an energy of which is determined self-consistently with an electron concentration. Main attention is paid to a Landau level (LL) pinning effect. Pinning means a fixation of the LL on a common Fermi level of the 2D and the 3D systems in a finite range of the magnetic field due to an electron transfer from the 2D to the 3D system. A condition and a start of LL pinning has been found for homogeneously broadened LLs. The electronic transfer from the 3D to the 2D system controls an extremely sharp magnetic dependency of an energy of the upper filled LL at integer filling of the LLs. This can cause a significant increase of inhomogeneous broadening of the upper LL that was observed in recent local probe experiments.Comment: 12 pages, 2 figures, revtex

Dry matter yields and quality of organic lupin/cereal mixtures for wholecrop forage

In view of climate change predictions and the general desirability of increasing the amount of home grown protein, a case exists for the investigation of lupins and lupin/cereal bicrop combinations as wholecrop forage on organic farms. A replicated randomised block trial is described which took place at the Royal Agricultural College, Cirencester, in 2005. This involved spring sown blue, white and yellow lupins, millet, wheat and triticale and lupin/cereal bi-crops. Data for dry matter yields for wholecrop silage, crude protein, MAD fi bre content and estimated ME, are presented for a single harvest. It is concluded that white lupins and white lupin bi-crops with spring wheat or triticale offer the best prospects for a viable wholecrop forage crop in an organic situation

BiSON data preparation: A correction for differential extinction and the weighted averaging of contemporaneous data

The Birmingham Solar Oscillations Network (BiSON) has provided high-quality high-cadence observations from as far back in time as 1978. These data must be calibrated from the raw observations into radial velocity and the quality of the calibration has a large impact on the signal-to-noise ratio of the final time series. The aim of this work is to maximise the potential science that can be performed with the BiSON data set by optimising the calibration procedure. To achieve better levels of signal-to-noise ratio we perform two key steps in the calibration process: we attempt a correction for terrestrial atmospheric differential extinction; and the resulting improvement in the calibration allows us to perform weighted averaging of contemporaneous data from different BiSON stations. The improvements listed produce significant improvement in the signal-to-noise ratio of the BiSON frequency-power spectrum across all frequency ranges. The reduction of noise in the power spectrum will allow future work to provide greater constraint on changes in the oscillation spectrum with solar activity. In addition, the analysis of the low-frequency region suggests we have achieved a noise level that may allow us to improve estimates of the upper limit of g-mode amplitudes.Comment: Accepted for publication in MNRAS; 10 pages, 7 figure

The Fulling-Davies-Unruh Effect is Mandatory: The Proton's Testimony

We discuss the decay of accelerated protons and illustrate how the Fulling-Davies-Unruh effect is indeed mandatory to maintain the consistency of standard Quantum Field Theory. The confidence level of the Fulling-Davies-Unruh effect must be the same as that of Quantum Field Theory itself.Comment: Awarded "honorable mention" by Gravity Research Foundation in the 2002 Essay competitio

Parametrizing the time-variation of the "surface term" of stellar p-mode frequencies: application to helioseismic data

The solar-cyle variation of acoustic mode frequencies has a frequency dependence related to the inverse mode inertia. The discrepancy between model predictions and measured oscillation frequencies for solar and solar-type stellar acoustic modes includes a significant frequency-dependent term known as the surface term that is also related to the inverse mode inertia. We parametrize both the surface term and the frequency variations for low-degree solar data from Birmingham Solar-Oscillations Network (BiSON) and medium-degree data from the Global Oscillations Network Group (GONG) using the mode inertia together with cubic and inverse frequency terms. We find that for the central frequency of rotationally split multiplets the cubic term dominates both the average surface term and the temporal variation, but for the medium-degree case the inverse term improves the fit to the temporal variation. We also examine the variation of the even-order splitting coefficients for the medium-degree data and find that, as for the central frequency, the latitude-dependent frequency variation, which reflects the changing latitudinal distribution of magnetic activity over the solar cycle, can be described by the combination of a cubic and an inverse function of frequency scaled by inverse mode inertia. The results suggest that this simple parametrization could be used to assess the activity-related frequency variation in solar-like asteroseismic targets.Comment: 13 pages, 11 figures. Accepted by MNRAS 13 October 201

The Energy-Momentum Tensor in Fulling-Rindler Vacuum

The energy density in Fulling-Rindler vacuum, which is known to be negative "everywhere" is shown to be positive and singular on the horizons in such a fashion as to guarantee the positivity of the total energy. The mechanism of compensation is displayed in detail.Comment: 9 pages, ULB-TH-15/9

The spin vector of Venus determined from Magellan data

A control network of the north polar region of Venus has been established by selecting and measuring control points on full-resolution radar strips. The measurements were incorporated into a least-squares adjustment program that improved initial estimates of the coordinates of the control points, pole direction, and rotation rate of Venus. The current dataset contains 4206 measurements of 606 points on 619 radar strips. The accuracy of the determination is driven by spacecraft ephemeris errors. An accurate estimate of the rotation period of Venus was obtained by applying an ephemeris improvement technique. The second cycle closure orbits improved ephemeris solutions for 40 orbits (376-384, 520-528, 588-592, 658-668, 1002-1010, 1408-1412, 1746-1764, and 2166-2170) are included and fixed in the geodetic control computations, thus trying the network to the J2000 coordinate system

Progress in materials and structures at Lewis Research Center

The development of power and propulsion system technology is discussed. Specific emphasis is placed on the following: high temperature materials; composite materials; advanced design and life prediction; and nondestructive evaluation. Future areas of research are also discussed

Performance of the Birmingham Solar-Oscillations Network (BiSON)

The Birmingham Solar-Oscillations Network (BiSON) has been operating with a full complement of six stations since 1992. Over 20 years later, we look back on the network history. The meta-data from the sites have been analysed to assess performance in terms of site insolation, with a brief look at the challenges that have been encountered over the years. We explain how the international community can gain easy access to the ever-growing dataset produced by the network, and finally look to the future of the network and the potential impact of nearly 25 years of technology miniaturisation.Comment: 31 pages, 19 figures. Accepted by Solar Physics: 2015 October 20. First online: 2015 December 7. Open Acces

Rotational quantum friction in superfluids: Radiation from object rotating in superfluid vacuum

We discuss the friction experienced by the body rotating in superfluid liquid at T=0. The effect is analogous to the amplification of electromagnetic radiation and spontaneous emission by the body or black hole rotating in quantum vacuum, first discussed by Zel'dovich and Starobinsky. The friction is caused by the interaction of the part of the liquid, which is rigidly connected with the rotating body and thus represents the comoving detector, with the "Minkowski" vacuum outside the body. The emission process is the quantum tunneling of quasiparticles from the detector to the ergoregion, where the energy of quasiparticles is negative in the rotating frame. This quantum rotational friction caused by the emission of quasiparticles is estimated for phonons and rotons in superfluid 4He and for Bogoliubov fermions in superfluid 3He.Comment: RevTex file, 4 pages, 1 figur