Light-sheet microscopy offers faster imaging and reduced phototoxicity in comparison to conventional point-scanning microscopy, making it a preferred technique for imaging biological dynamics for durations of hours or days. Such extended imaging sessions pose a challenge, as it reduces the number of specimens that can be imaged in a given day. Here, we present a versatile light-sheet imaging instrument that combines two independently controlled microscope-twins, built so that they can share an ultrafast near-infrared laser and a bank of continuous-wave visible lasers, increasing the throughput and decreasing the cost. To permit a wide variety of specimens to be imaged, each microscope-twin provides flexible imaging parameters, including (i) operation in one-photon and/or two-photon excitation modes, (ii) delivery of one to three light-sheets via a trio of orthogonal excitation arms, (iii) sub-micron to micron imaging resolution, (iv) multicolor compatibility, and (v) upright (with provision for inverted) detection geometry. We offer a detailed description of the twin-microscope design to aid instrument builders who wish to construct and use similar systems. We demonstrate the instrument’s versatility for biological investigation by performing fast imaging of the beating heart in an intact zebrafish embryo, deep imaging of thick patient-derived tumor organoids, and gentle whole-brain imaging of neural activity in behaving larval zebrafish.Cryogenic helium-4 has extremely small kinetic viscosity, which makes it a promising material for high Reynolds (Re) number turbulence research in compact laboratory apparatus. In its superfluid phase (He II), helium has an extraordinary heat transfer capability and has been utilized in various scientific and engineering applications. In order to unlock the full potential of helium in turbulence research and to improve our understanding of the heat transfer mechanism in He II, a flow facility that allows quantitative study of helium heat-and-mass transfer processes is needed. Here, we report our work in assembling and testing a unique helium pipe-flow facility that incorporates a novel double-line molecular tagging velocimetry (DL-MTV) system. This flow facility allows us to generate turbulent pipe flows with Re above 107, and it can also be adapted to produce heat-induced counterflow in He II. The DL-MTV system, which is based on the generation and tracking of two parallel thin He2 * molecular tracer lines with an adjustable separation distance, allows us to measure not only the velocity profile but also both the transverse and longitudinal spatial velocity structure functions. We have also installed a differential pressure sensor on the flow pipe for pressure drop measurements. The testing results of the flow facility and the measuring instruments are presented. We discuss how this facility will allow us to solve some outstanding problems in the helium heat-and-mass transfer topic area.Quartz crystal resonators are suitable for digital output sensors due to their sensitivity to force. This paper presents a highly sensitive inclinometer sensor with a quartz resonator cluster. The force sensitive resonator cluster is designed on the quartz substrate to eliminate common-mode disturbances, such as temperature, as well as to improve sensitivity to force. The inclinometer sensor comprises two quartz resonator clusters that form a push-pull structure. The difference in inclination causes gravitational acceleration to produce an axial force along the input axis, with the resonance frequency shifting in proportion to the axial force. A signal processing and fusion scheme for the inclinometer sensor is presented and then tested. GSK1904529A mw The results show that the scale factor of the sensor prototype is 3.5102 Hz/1′ and that nonlinearity is 1.040% full scale in the range of -2°-+2°. The resolution of the inclinometer sensor is better than 0.0055°, making these devices a potentially attractive option for numerous precision inclination measurement applications.This paper considers the application of Field Programmable Gate Array (FPGA)-based infinite impulse response (IIR) filtering to increase the usable bandwidth of a piezoelectric transducer used in optical phase locking. We experimentally perform system identification of the interferometer with the cross-correlation method integrated on the controller hardware. Our model is then used to implement an inverse filter designed to suppress the low frequency resonant modes of the piezoelectric transducer. This filter is realized as a 24th-order IIR filter on the FPGA, while the total input-output delay is kept at 350 ns. The combination of the inverse filter and the piezoelectric transducer works as a nearly flat response position actuator, allowing us to use a proportional-integral (PI) control in order to achieve stability of the closed-loop system with significant improvements over a non-filtered PI control. Finally, because this controller is completely digital, it is straightforward to reproduce. Our control scheme is suitable for many experiments that require highly accurate control of flexible structures.Dielectric measurements on insulating materials at cryogenic temperatures can be challenging, depending on the frequency and temperature ranges of interest. We present a technique to study the dielectric properties of bulk dielectrics at GHz frequencies. A superconducting coplanar Nb resonator is deposited directly on the material of interest, and this resonator is then probed in distant-flip-chip geometry with a microwave feedline on a separate chip. Evaluating several harmonics of the resonator gives access to various probing frequencies in the present studies up to 20 GHz. We demonstrate the technique on three different materials (MgO, LaAlO3, and TiO2), at temperatures between 1.4 K and 7 K.Photonic Doppler Velocimetry (PDV) is a fiber-based diagnostic for the extreme conditions created by high-speed impact, explosive detonation, electrical pulsed power, and intense laser ablation. PDV is a conceptually simple application of the optical Doppler effect, but measurements above 1 km/s only became practical at the beginning of the twenty-first century. This review discusses the evolution of PDV, its operational details, practical analysis, and outstanding challenges.