162 research outputs found

    Designing smart pulse flow meters using diversion analysis

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    The operation of modern housing infrastructure is characterized by a constant increase in the cost of the limited resources used. This necessitates the priority implementation in the concept of a smart home of elements aimed at resource saving and their rational management. The study provides an overview of the implementation architectures of the internet of things (IoT) concept in the construction of home automation systems and the requirements they impose on the implementation of smart primary meters of controlled physical quantities. Based on a diversion analysis, a promising smart water meter was developed. The prototype is ergonomic and has a structural form factor convenient for further integration. The designed model of the electronic module of the water flow monitoring system implements, in addition to typical tasks, additional functionality: transfer of recorded indicators and technical information to the cloud storage, warning the user about an emergency situation, accumulation of current data in non-volatile memory. It is possible to use the accumulated statistics for training the predictive analysis module. The proposed architecture option will allow creating energy-efficient elements of home automation systems in the future

    Extreme plasma states in laser-governed vacuum breakdown

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    Triggering vacuum breakdown at the upcoming laser facilities can provide rapid electron-positron pair production for studies in laboratory astrophysics and fundamental physics. However, the density of the emerging plasma should seemingly stop rising at the relativistic critical density, when the plasma becomes opaque. Here we identify the opportunity of breaking this limit using optimal beam configuration of petawatt-class lasers. Tightly focused laser fields allow plasma generation in a small focal volume much less than λ3{\lambda}^3, and creating extreme plasma states in terms of density and produced currents. These states can be regarded as a new object of nonlinear plasma physics. Using 3D QED-PIC simulations we demonstrate the possibility of reaching densities of more than 102510^{25} cm3^{-3}, which is an order of magnitude higher than previously expected. Controlling the process via the initial target parameters gives the opportunity to reach the discovered plasma states at the upcoming laser facilities

    Overtones of Isoscalar Giant Resonances in medium-heavy and heavy nuclei

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    A semi-microscopic approach based on both the continum-random-phase-approximation (CRPA) method and a phenomenological treatment of the spreading effect is extended and applied to describe the main properties (particle-hole strength distribution, energy-dependent transition density, partial direct-nucleon-decay branching ratios) of the isoscalar giant dipole, second monopole, and second quadrupole resonances. Abilities of the approach are checked by description of gross properties of the main-tone resonances. Calculation results obtained for the resonances in a few singly- and doubly-closed-shell nuclei are compared with available experimental data.Comment: 12 pages, 14 figures, submitted to Phys. Rev.

    Semimicroscopical description of the simplest photonuclear reactions accompanied by excitation of the giant dipole resonance in medium-heavy mass nuclei

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    A semimicroscopical approach is applied to describe photoabsorption and partial photonucleon reactions accompanied by the excitation of the giant dipole resonance (GDR). The approach is based on the continuum-RPA (CRPA) with a phenomenological description for the spreading effect. The phenomenological isoscalar part of the nuclear mean field, momentum-independent Landau-Migdal particle-hole interaction, and separable momentum-dependent forces are used as input quantities for the CRPA calculations. The experimental photoabsorption and partial (n,γ)(n,\gamma)-reaction cross sections in the vicinity of the GDR are satisfactorily described for 89^{89}Y, 140^{140}Ce and 208^{208}Pb target nuclei. The total direct-neutron-decay branching ratio for the GDR in 48^{48}Ca and 208^{208}Pb is also evaluated.Comment: 19 pages, 5 eps figure

    Quantum cascade laser intracavity absorption spectrometer for trace gas sensing

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    A mid-infrared intracavity laser absorption spectrometer for trace gas sensing is demonstrated. An external-cavity multi-mode quantum cascade laser with central wavelength 8.0 mu m was combined with a scanning Fabry-Perot interferometer, which analyzed the change of the laser emission spectrum caused by introducing an analyte inside the cavity. The detection mechanism is based on monitoring the laser spectrum dynamics at adiabatically changing laser conditions in long pulse operation mode. Fast acquisition and vapor exchange allow nearly real-time analyte detection. Sensitivity at the level of 1 x 10(-5) cm(-1) was demonstrated based on a weak water vapor absorption line
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