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A liquid crystal‐cladding waveguide with resistive electrode configuration is proposed for laser beam steering applications. It can achieve wide‐angle, continuous coverage, two‐dimensional beam control with fast response time. With numerical validation, we find that in comparison with previous prismatic electrode approach, our device demonstrates higher compatibility with high birefringence liquid crystal materials, and thus, a more compact form factor can be realized. Such a beam steerer is attractive for a wide range of applications including automotive LiDAR, eye‐tracking for near‐eye displays, and high‐precision 3D printing. [ABSTRACT FROM AUTHOR]

A liquid crystal‐cladding waveguide with resistive electrode configuration is proposed for laser beam steering applications. It can achieve wide‐angle continuous coverage two‐dimensional beam control with fast response time. With numerical validation, we find that in comparison with previous prismatic electrode approach, our device demonstrates higher compatibility with high birefringence liquid crystal materials, and thus a more compact form factor can be realized. Such a beam steerer is attractive for a wide range of applications including automotive LiDAR, eye‐tracking for near‐eye displays, and high‐precision 3D printing. [ABSTRACT FROM AUTHOR]

Abstract An open source compact and general tool, implemented in OpenFOAM including a novel solver with a new boundary condition and post-processing utilities, is derived to enable calculations of local current and potential distributions in electrochemical systems with activated or resistive electrodes and also leakage currents in the case of a bipolar connection. The algorithm allows the calculations for a given local potential in any electrode, for a fixed cell potential difference and also for a current flowing through the cell under galvanostatic control. In order to validate the algorithm, a detailed comparison between the suggested strategy with experimental results and some simplified theoretical models is made. It was concluded that the proposed mathematical treatment is reliable for the modelling of these electrochemical systems due to the good agreement between theoretical and experimental values with a mean relative percent error of 8.8 ± 2.1% for the current distribution for the whole set of experiments. Highlights • An open source algorithm was validated with theoretical and experimental results. • A multiregion approach avoids current conservation at electrodes as constrain. • The increase in current produces a less uniform current distribution. • Feeding by the middle point decrease the leakage current. • Resistive electrodes affect negatively the reactor performance. [ABSTRACT FROM AUTHOR]

Abstract: In the present paper a concept of static and dynamic shape control for slender piezoelastic beams is addressed. The notion shape control means to find a weighting sequence for the piezoelectric control units, such that force-induced lateral deflections are completely annihilated along the beam axis. In our case this spatial control intensity for the piezoelectric transducers is realized with so-called resistive electrodes: by prescribing only the maximum and minimum voltage level, any desirable voltage distribution along the beam axis may be obtained. For the derivation of the shape control method an extended version of the Bernoulli–Euler beam theory is used, which unifies the kinematics of a slender piezoelectric beam and the Telegrapher’s equations for moderately conductive electrodes. The outcome is an actuator equation for the displacement, which is fourth order in space and second order in time, and a sensor equation, which is second order in space and first order in time (diffusion equation for the voltage). The developed shape control method is verified by several numerical examples in the static case as well as in the dynamic frequency regime for a clamped-free beam. We show that the presented method is perfectly suited for static loads, being able to cancel force-induced structural deformations along the beam axis, whereas the deflections in the higher frequency regime can be nearly canceled out. The method is efficient, as long as a non-dimensional constant, involving the resistance, the capacitance per unit length, the length of the electrodes and the excitation frequency, is small. [Copyright &y& Elsevier]

An attractive method of two-dimensional localization based on charge division with Ni–Cr resistive strips has been adapted to a Micromegas detector taking advantage of its high gain. Along the strips, depending on the signal to noise ratio, 1.05 mm–300 μm spatial resolutions (respectively, 0.80–0.23% of the strip length) are obtained with an 3H source. For trajectory reconstruction in magnetic fields, these accuracies could match most of the localization constraints requested for measurements of the non-bending coordinate. In the direction perpendicular to the strips, localizations better than 100 μm could be achieved using the center of gravity of the charges. [Copyright &y& Elsevier]

A novel type of resistive Micromegas combining a Bulk mesh and a resistive pad board is presented. Readout pads are covered by a thin insulating layer with a top resistive coating segmented into resistive pads. Readout and resistive pads are electrically connected by means of planar resistors embedded in the insulator, enabling fast clearance of the avalanche charge from the resistive surface. The maximum gas gain achieved by these resistive detectors is similar to that of non-resistive Micromegas. A possible saturation of the gain for large energy deposits in the gas was investigated by means of 55Fe quanta and electromagnetic showers in the 30–200 GeV energy range, but no significant deviation from a proportional response was found. With a suitable choice of the resistance, these detectors demonstrate negligible gain drop and no sparking up to X-ray fluxes of ∼ 1 MHz / mm2 which constitutes a major improvement over non-resistive Micromegas. Spark suppression was also verified in a hadron beam for prototypes with a pad resistance as low as 40 k Ω or above. Passive protections of the front-end electronics against sparks (diodes on a printed circuit board) are therefore not required for these resistive detectors. [ABSTRACT FROM AUTHOR]

Digital and Semi-Digital Hadronic Calorimeters (S)DHCAL were suggested for future Colliders as part of the particle-flow concept. Though studied mostly with RPC-based techniques, investigations have shown that Micro Pattern Gaseous Detector (MPGD)-based sampling elements could outperform in terms of average pad multiplicity or at higher rates. An attractive, industry-produced, robust, particle-tracking detector for large-area coverage, e.g. in (S)DHCAL, could be the novel single-stage Resistive Plate WELL (RPWELL). It is a single-sided THick Gaseous Electron Multiplier (THGEM) coupled to the segmented readout electrode through a sheet of large bulk resistivity. We summarize here the preliminary test-beam results obtained with 6.5 mm thick (incl. electronics) 48 × 48 cm 2 RPWELL detectors. Two configurations are considered: a standalone RPWELL detector studied with 150 GeV muons and high-rate pions beams and a RPWELL sampling element investigated within a small-(S)DHCAL prototype consisting of 7 resistive Micro-MEsh Gaseous Structure (MICROMEGAS) sampling elements followed by 5 RPWELL ones. The sampling elements were equipped with a Semi-Digital readout electronics based on the MICROROC chip. [ABSTRACT FROM AUTHOR]