9,311 research outputs found

    Fuse and switch functions combined within a single housing

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    Fuswitch provides both switch and fuse functions within a single housing. A mercury capillary is used to alternately vaporize and condense the mercury within a reservoir. The housing is impervious to mercury and the fuse portion of the device operates on the principle of the self-healing mercury fuse

    Global Classical Solutions of the Boltzmann Equation with Long-Range Interactions and Soft Potentials

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    In this work we prove global stability for the Boltzmann equation (1872) with the physical collision kernels derived by Maxwell in 1866 for the full range of inverse power intermolecular potentials, r−(p−1)r^{-(p-1)} with p>2p>2. This completes the work which we began in (arXiv:0912.0888v1). We more generally cover collision kernels with parameters s∈(0,1)s\in (0,1) and γ\gamma satisfying γ>−(n−2)−2s\gamma > -(n-2)-2s in arbitrary dimensions Tn×Rn\mathbb{T}^n \times \mathbb{R}^n with n≥2n\ge 2. Moreover, we prove rapid convergence as predicted by the Boltzmann H-Theorem. When γ+2s≥0\gamma + 2s \ge 0, we have exponential time decay to the Maxwellian equilibrium states. When γ+2s<0\gamma + 2s < 0, our solutions decay polynomially fast in time with any rate. These results are constructive. Additionally, we prove sharp constructive upper and lower bounds for the linearized collision operator in terms of a geometric fractional Sobolev norm; we thus observe that a spectral gap exists only when γ+2s≥0\gamma + 2s \ge 0, as conjectured in Mouhot-Strain (2007).Comment: This file has not changed, but this work has been combined with (arXiv:0912.0888v1), simplified and extended into a new preprint, please see the updated version: arXiv:1011.5441v

    Single-shot electro-optic sampling of coherent transition radiation at the A0 Photoinjector

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    Future collider applications and present high-gradient laser plasma wakefield accelerators operating with picosecond bunch durations place a higher demand on the time resolution of bunch distribution diagnostics. This demand has led to significant advancements in the field of electro-optic sampling over the past ten years. These methods allow the probing of diagnostic light such as coherent transition radiation or the bunch wakefields with sub-picosecond time resolution. Potential applications in shot-to-shot, non-interceptive diagnostics continue to be pursued for live beam monitoring of collider and pump-probe experiments. Related to our developing work with electro-optic imaging, we present results on single-shot electro-optic sampling of the coherent transition radiation from bunches generated at the A0 photoinjector.Comment: 3 p

    Series of experiments for empirical validation of solar gain modelling in building energy simulation codes - experimental setup, test cell characterization, specifications and uncertainty analysis

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    Empirical validation of building energy simulation codes is an important component in understanding the capacity and limitations of the software. Within the framework of Task 34/Annex 43 of the International Energy Agency (IEA), a series of experiments was performed in an outdoor test cell. The objective of these experiments was to provide a high-quality data set for code developers and modelers to validate their solar gain models for windows with and without shading devices. A description of the necessary specifications for modeling these experiments is provided in this paper, which includes information about the test site location, experimental setup, geometrical and thermophysical cell properties including estimated uncertainties. Computed overall thermal cell properties were confirmed by conducting a steady-state experiment without solar gains. A transient experiment, also without solar gains, and corresponding simulations from four different building energy simulation codes showed that the provided specifications result in accurate thermal cell modeling. A good foundation for the following experiments with solar gains was therefore accomplished

    Unitarity of the infinite-volume three-particle scattering amplitude arising from a finite-volume formalism

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    In a previous publication, two of us derived a relation between the scattering amplitude of three identical bosons, M3\mathcal M_3, and a real function referred to as the {divergence-free} K matrix and denoted Kdf,3\mathcal K_{\text{df},3}. The result arose in the context of a relation between finite-volume energies and Kdf,3\mathcal K_{\text{df},3}, derived to all orders in the perturbative expansion of a generic low-energy effective field theory. In this work we set aside the role of the finite volume and focus on the infinite-volume relation between Kdf,3\mathcal K_{\text{df},3} and M3\mathcal M_3. We show that, for any real choice of Kdf,3\mathcal K_{\text{df},3}, M3\mathcal M_3 satisfies the three-particle unitarity constraint to all orders. Given that Kdf,3\mathcal K_{\text{df},3} is also free of a class of kinematic divergences, the function may provide a useful tool for parametrizing three-body scattering data. Applications include the phenomenological analysis of experimental data (where the connection to the finite volume is irrelevant) as well as calculations in lattice quantum chromodynamics (where the volume plays a key role).Comment: 19 pages, 4 figures, JLAB-THY-19-2945, CERN-TH-2019-07

    Formation and Acceleration of Uniformly-Filled Ellipsoidal Electron Bunches Obtained via Space-Charge-Driven Expansion from a Cesium-Telluride Photocathode

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    We report the experimental generation, acceleration and characterization of a uniformly-filled electron bunch obtained via space-charge-driven expansion (often referred to as "blow-out regime") in an L-band (1.3-GHz) radiofrequency photoinjector. The beam is photoemitted from a Cesium-Telluride semiconductor photocathode using a short (<200<200 fs) ultraviolet laser pulse. The produced electron bunches are characterized with conventional diagnostics and the signatures of their ellipsoidal character is observed. We especially demonstrate the production of ellipsoidal bunches with charges up to ∼0.5\sim0.5 nC corresponding to a ∼20\sim20-fold increase compared to previous experiments with metallic photocathodes.Comment: 9, pages, 13 figure

    The exposure history of the Apollo 16 site: An assessment based on methane and hydrolysable carbon

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    Nineteen soils from eight stations at the Apollo 16 landing site have been analyzed for methane and hydrolysable carbon. These results, in conjunction with published data from photogeology, bulk chemistry, rare gases, primordial and cosmogenic radionuclides, and agglutinate abundances have been interpreted in terms of differing contributions from three components-North and South Ray Crater ejecta and Cayley Plains material

    Tunable subpicosecond electron bunch train generation using a transverse-to-longitudinal phase space exchange technique

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    We report on the experimental generation of a train of subpicosecond electron bunches. The bunch train generation is accomplished using a beamline capable of exchanging the coordinates between the horizontal and longitudinal degrees of freedom. An initial beam consisting of a set of horizontally-separated beamlets is converted into a train of bunches temporally separated with tunable bunch duration and separation. The experiment reported in this Letter unambiguously demonstrates the conversion process and its versatility.Comment: 4 pages, 5 figures, 1 table; accepted for publication in PR
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