Measurement of Gravitomagnetic and Acceleration Fields Around Rotating Superconductors

It is well known that a rotating superconductor produces a magnetic field proportional to its angular velocity. The authors conjectured earlier, that in addition to this so-called London moment, also a large gravitomagnetic field should appear to explain an apparent mass increase of Niobium Cooper-pairs. A similar field is predicted from Einstein's general relativity theory and the presently observed amount of dark energy in the universe. An experimental facility was designed and built to measure small acceleration fields as well as gravitomagnetic fields in the vicinity of a fast rotating and accelerating superconductor in order to detect this so-called gravitomagnetic London moment. This paper summarizes the efforts and results that have been obtained so far. Measurements with Niobium superconductors indeed show first signs which appear to be within a factor of 2 of our theoretical prediction. Possible error sources as well as the experimental difficulties are reviewed and discussed. If the gravitomagnetic London moment indeed exists, acceleration fields could be produced in a laboratory environment.Comment: To appear in the proceedings of the STAIF-2007 conference published by AI

Can the Tajmar effect be explained using a modification of inertia?

The Tajmar effect is an unexplained acceleration observed by accelerometers and laser gyroscopes close to rotating supercooled rings. The observed ratio between the gyroscope and ring accelerations was 3+/-1.2x10^-8. Here, a new model for inertia which has been tested quite successfully on the Pioneer and flyby anomalies is applied to this problem. The model assumes that the inertia of the gyroscope is caused by Unruh radiation that appears as the ring and the fixed stars accelerate relative to it, and that this radiation is subject to a Hubble-scale Casimir effect. The model predicts that the sudden acceleration of the nearby ring causes a slight increase in the inertial mass of the gyroscope, and, to conserve momentum in the reference frame of the spinning Earth, the gyroscope rotates clockwise with an acceleration ratio of 1.8+/-0.25x10^-8 in agreement with the observed ratio. However, this model does not explain the parity violation seen in some of the gyroscope data. To test these ideas the Tajmar experiment (setup B) could be exactly reproduced in the southern hemisphere, since the model predicts that the anomalous acceleration should then be anticlockwise.Comment: 9 pages, 1 figure. Accepted by EPL on the 4th December, 200

Laser power stabilization for second-generation gravitational wave detectors

We present results on the power stabilization of a Nd:YAG laser in the frequency band from 1 Hz to 100 kHz. High-power, low-noise photodetectors are used in a dc-coupled control loop to achieve relative power fluctuations down to 5×10−9 Hz−1/2 at 10 Hz and 3.5×10−9 Hz−1/2 up to several kHz, which is very close to the shot-noise limit for 80 mA of detected photocurrent on each detector. We investigated and eliminated several noise sources such as ground loops and beam pointing. The achieved stability level is close to the requirements for the Advanced LIGO gravitational wave detector

Evaluation of selected chemical processes for production of low-cost silicon, phase 3

A Process Development Unit (PDU), which consisted of the four major units of the process, was designed, installed, and experimentally operated. The PDU was sized to 50MT/Yr. The deposition took place in a fluidized bed reactor. As a consequences of the experiments, improvements in the design an operation of these units were undertaken and their experimental limitations were partially established. A parallel program of experimental work demonstrated that Zinc can be vaporized for introduction into the fluidized bed reactor, by direct induction-coupled r.f. energy. Residual zinc in the product can be removed by heat treatment below the melting point of silicon. Current efficiencies of 94 percent and above, and power efficiencies around 40 percent are achievable in the laboratory-scale electrolysis of ZnCl2

Measurements of greenhouse gases and related tracers at Bialystok tall tower station in Poland

Quasi-continuous, in-situ measurements of atmospheric CO2, O2/N2, CH4, CO, N2O, and SF6 have been performed since August 2005 at the tall tower station near Bialystok, in Eastern Poland, from five heights up to 300 m. Besides the in-situ measurements, flask samples are filled approximately weekly and measured at Max-Planck Institute for Biogeochemistry for the same species and, in addition, for H2, Ar/N2 and the stable isotopes 13C and 18O in CO2. The in-situ measurement system was built based on commercially available analysers: a LiCor 7000 for CO2, a Sable Systems "Oxzilla" FC-2 for O2, and an Agilent 6890 gas chromatograph for CH4, CO, N2O and SF6. The system was optimized to run continuously with very little maintenance and to fulfill the precision requirements of the CHIOTTO project. The O2/N2 measurements in particular required special attention in terms of technical setup and quality assurance. The evaluation of the performance after more than three years of operation gave overall satisfactory results, proving that this setup is suitable for long term remote operation with little maintenance. The precision achieved for all species is within or close to the project requirements. The comparison between the in-situ and flask sample results, used to verify the accuracy of the in-situ measurements, showed no significant difference for CO2, O2/N2, CH4 and N2O, and a very small difference for SF6. The same comparison however revealed a statistically significant difference for CO, of about 6.5 ppb, for which the cause could not be fully explained. From more than three years of data, the main features at Bialystok have been characterized in terms of variability, trends, and seasonal and diurnal variations. CO2 and O2/N2 show large short term variability, and large diurnal signals during the warm seasons, which attenuate with the increase of sampling height. The trends calculated from this dataset, over the period August 2005 to December 2008, are 2.02±0.46 ppm/year for CO2 and -23.2±2.5 per meg/year for O2/N2. CH4, CO and N2O show also higher variability at the lower sampling levels, which in the case of CO is strongly seasonal. Diurnal variations in CH4, CO and N2O mole fractions can be observed during the warm season, due to the periodicity of vertical mixing combined with the diurnal cycle of anthropogenic emissions. We calculated increase rates of 10.1±4.4 ppb/year for CH4, (-8.3)±5.3 ppb/year for CO and 0.67±0.08 ppb/year for N2O. SF6 shows only few events, and generally no vertical gradients, which suggests that there are no significant local sources. A weak SF6 seasonal cycle has been detected, which most probably is due to the seasonality of atmospheric circulation. SF6 increased during the time of our measurement at an average rate of 0.29±0.01 ppt/year

Bilayer Membrane in Confined Geometry: Interlayer Slide and Steric Repulsion

We derived free energy functional of a bilayer lipid membrane from the first principles of elasticity theory. The model explicitly includes position-dependent mutual slide of monolayers and bending deformation. Our free energy functional of liquid-crystalline membrane allows for incompressibility of the membrane and vanishing of the in-plane shear modulus and obeys reflectional and rotational symmetries of the flat bilayer. Interlayer slide at the mid-plane of the membrane results in local difference of surface densities of the monolayers. The slide amplitude directly enters free energy via the strain tensor. For small bending deformations the ratio between bending modulus and area compression coefficient, Kb/KA, is proportional to the square of monolayer thickness, h. Using the functional we performed self-consistent calculation of steric potential acting on bilayer between parallel confining walls separated by distance 2d. We found that temperature-dependent curvature at the minimum of confining potential is enhanced four times for a bilayer with slide as compared with a unit bilayer. We also calculate viscous modes of bilayer membrane between confining walls. Pure bending of the membrane is investigated, which is decoupled from area dilation at small amplitudes. Three sources of viscous dissipation are considered: water and membrane viscosities and interlayer drag. Dispersion has two branches. Confinement between the walls modifies the bending mode with respect to membrane in bulk solution. Simultaneously, inter-layer slipping mode, damped by viscous drag, remains unchanged by confinement.Comment: 23 pages,3 figures, pd

Giant vesicles at the prolate-oblate transition: A macroscopic bistable system

Giant phospholipid vesicles are shown to exhibit thermally activated transitions between a prolate and an oblate shape on a time scale of several seconds. From the fluctuating contour of such a vesicle we extract ellipticity as an effective reaction coordinate whose temporal probability distribution is bimodal. We then reconstruct the effective potential from which we derive an activation energy of the order of $k_BT$ in agreement with theoretical calculations. The dynamics of this transition is well described within a Kramers model of overdamped diffusion in a bistable potential. Thus, this system can serve as a model for macroscopic bistability.Comment: 10 pages, LaTeX, epsfig, 4 eps figures included, to appear in Europhys. Let

In-situ measurements of oxygen, carbon monoxide and greenhouse gases from Ochsenkopf tall tower in Germany

We present 2.5 years (from June 2006 to December 2008) of in-situ measurements of CO2, O2, CH4, CO, N2O and SF6 mixing ratios sampled from 23, 90 and 163m above ground on the Ochsenkopf tower in the Fichtelgebirge range, Germany (50?0104900 N, 11?4803000 E, 1022ma.s.l.). In addition to the in-situ measurements, flask samples are taken at Ochsenkopf at approximately weekly intervals and are subsequently analysed for the mixing ratios of the same species, as well as H2, and the stable isotopes, ?13C, ?18O in CO2. The in-situ measurements of CO2 and O2 from 23m show substantial diurnal variations that are modulated by biospheric fluxes, combustion of fossil fuels, and by diurnal changes in the planetary boundary layer height. Measurements from 163m exhibit only very weak diurnal variability, as this height (1185ma.s.l.) is generally above the nocturnal boundary layer. CH4, CO, N2O and SF6 show little diurnal variation even at 23m owing to the absence of any significant diurnal change in the fluxes and the absence of any strong local sources or sinks. From the in-situ record, the seasonal cycles of the gas species have been characterized and the multi-annual trends determined. Because the record is short, the calculation of the trend is sensitive to inter-annual variations in the amplitudes of the seasonal cycles. However, for CH4 a significant change in the growth-rate was detected for 2006.5–2008.5 as compared with the global mean from 1999 to 2006 and is consistent with other recent observations of a renewed increasing global growth rate in CH4 since the beginning of 2007