1,356 research outputs found

    The Superposition Principle of Waves Not Fulfilled under M. W. Evans' O(3) Hypothesis

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    In 1992 M.W. Evans proposed a so-called O(3) symmetry of electromagnetic fields by adding a constant longitudinal "ghost field" to the well-known transversal plane em waves. He considered this symmetry as a new law of electromagnetics. Later on, since 2002, this O(3) symmetry became the center of his Generally Covariant Unified Field Theory which he recently renamed as ECE Theory. One of the best-checked laws of electrodynamics is the principle of linear superposition of electromagnetic waves, manifesting itself in interference phenomena. Its mathematical equivalent is the representation of electric and magnetic fields as vectors. By considering the superposition of two phase-shifted waves we show that the superposition principle is incompatible with M.W. Evans' O(3) hypothesis.Comment: 5 pages, no figure

    MRI of "diffusion" in the human brain: New results using a modified CE-FAST sequence.

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    “Diffusion-weighted” MRI in the normal human brain and in a patient with a cerebral metastasis is demonstrated. The method employed was a modified CE-FAST sequence with imaging times of only 6-10 s using a conventional 1.5-T whole-body MRI system (Siemens Magnetom). As with previous phantom and animal studies, the use of strong gradients together with macroscopic motions in vivo causes unavoidable artifacts in diffusion-weighted images of the human brain. While these artifacts are shown to be considerably reduced by averaging of 8-16 images, the resulting diffusion contrast is compromised by unknown signal losses due to motion

    Localized proton NMR spectroscopy in different regions of the human brain in vivo. Relaxation times and concentrations of cerebral metabolites.

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    High-resolution proton NMR spectra of normal human brain in vivo have been obtained from selected 27- and 64-ml volumes-of-interest (VOI) localized in the insular area, the occipital area, the thalamus, and the cerebellum of normal volunteers. Localization was achieved by stimulated echo (STEAM) sequences using a conventional 1.5-T whole-body MRI system (Siemens Magnetom). The proton NMR spectra show resonances from lipids, lactate, acetate, Nacetylaspartate (NAA), γ-aminobutyrate, glutamine, glutamate, aspartate, creatine and phosphocreatine, choline-containing compounds, taurine, and inositols. While T1 relaxation times of most of these metabolites were about 1100–1700 ms without significant regional differences, their T2 relaxation times varied between 100 and 500 ms. The longest T2 values of about (500 ± 50) ms were observed for the methyl protons of NAA in the white matter of the occipital lobe compared to (320 ± 30) ms in the other parts of the brain. No significant regional T2 differences were found for choline and creatine methyl resonances. The relative concentrations of NAA in gray and white matter were found to be 35% higher than those in the thalamus and cerebellum. Assuming a concentration of 10 mM for total creatine the resulting NAA concentrations of 13–18 mMare by a factor of 2–3 higher than previously reported using analytical techniques. Cerebral lactate reached a maximum concentration of about 1.0 mM

    Cryogenic silicon detectors with implanted contacts for the detection of visible photons using the Neganov-Luke Effect

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    There is a common need in astroparticle experiments such as direct dark matter detection, 0{\nu}\b{eta}\b{eta} (double beta decay without emission of neutrinos) and Coherent Neutrino Nucleus Scattering experiments for light detectors with a very low energy threshold. By employing the Neganov-Luke Effect, the thermal signal of particle interactions in a semiconductor absorber operated at cryogenic temperatures, can be amplified by drifting the photogenerated electrons and holes in an electric field. This technology is not used in current experiments, in particular because of a reduction of the signal amplitude with time which is due to trapping of the charges within the absorber. We present here the first results of a novel type of Neganov-Luke Effect detector with an electric field configuration designed to improve the charge collection within the semiconductor.Comment: 6 pages, 5 figures, submitted to Journal of Low Temperature Physic

    Sampling Plans for Control-Inspection Schemes Under Independent and Dependent Sampling Designs With Applications to Photovoltaics

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    The evaluation of produced items at the time of delivery is, in practice, usually amended by at least one inspection at later time points. We extend the methodology of acceptance sampling for variables for arbitrary unknown distributions when additional sampling infor- mation is available to such settings. Based on appropriate approximations of the operating characteristic, we derive new acceptance sampling plans that control the overall operating characteristic. The results cover the case of independent sampling as well as the case of dependent sampling. In particular, we study a modified panel sampling design and the case of spatial batch sampling. The latter is advisable in photovoltaic field monitoring studies, since it allows to detect and analyze local clusters of degraded or damaged modules. Some finite sample properties are examined by a simulation study, focusing on the accuracy of estimation
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