A Micromachined Geometric Moiré Interferometric Floating-Element Shear Stress Sensor

Horowitz, Stephen; Chen, T.; Chandrasekaran, V.; Tedjojuwono, Ken K.; Nishida, Toshikazu; Cattafesta, Louis N.; Sheplak, Mark

doi:10.2514/6.2004-1042

Cited by 28 publications

(12 citation statements)

References 20 publications

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“…A photodiode array with 16 elements is used to replace the original charge-coupled device (CCD) arrays for imaging 15 which reduces the amount of data for processing.…”

Section: Moiré Datamentioning

confidence: 99%

A miniaturized optical package for wall shear stress measurements in harsh environments

et al. 2014

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We report the development of a time-resolved direct wall shear stress senor using an optical moiré transduction technique for harsh environments. The floating-element sensor is a lateral-position sensor that is micromachined to enable sufficient bandwidth and to minimize spatial aliasing. The optical transduction approach offers several advantages over electrical-based floating element techniques including immunity from electromagnetic interference and the ability to operate in a conductive fluid medium. Packaging for optical sensors presents significant challenges. The bulky nature and size of conventional free-space optics often limit their use to an optical test bench, making them unsuitable for harsh environments. The optical package developed in this research utilizes an array of optical fibers mapped over the moiré fringe. The fiber bundle approach results in a robust package that reduces the overall size of the optics, mitigates vibration between the sensor and optoelectronics and enables in situ measurement. The optical package for sampling the amplified moiré fringe is evaluated using bench top test setups. An optical test bench is constructed to simulate the movement of the moiré fringe on the floating element. High-resolution images of the optical fringe and optical fibers are combined in simulation to model the lateral displacement of the fringe. The performance of several fringe estimation algorithms are studied and evaluated. Based on the optical study, the optical package and post-processing algorithms are implemented on an actual device. Initial device characterization using this approach results in a device sensitivity of 12.4 nm/Pa.

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“…A photodiode array with 16 elements is used to replace the original charge-coupled device (CCD) arrays for imaging 15 which reduces the amount of data for processing.…”

Section: Moiré Datamentioning

confidence: 99%

A miniaturized optical package for wall shear stress measurements in harsh environments

et al. 2014

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“…Horowitz et al [16]) is highly impractical in in-vitro hemodynamics experiments, and the use of pressure drop measurements to determine the wall shear stress implies averaging over a certain section, local wall shear stress values are usually determined from an estimate of the wall shear rate. When a Newtonian test fluid is used, shear stress is directly proportional to shear rate, with µ the proportionality constant.…”

Section: Papermentioning

confidence: 99%

Review of Experimental Modelling in Vascular Access for Hemodialysis

Drost

Alam

Houston

et al. 2017

Cardiovasc Eng Tech

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This paper reviews applications of experimental modelling in vascular access for hemodialysis. Different techniques that are used in in-vitro experiments are bulk pressure and flow rate measurements, Laser Doppler Velocimetry (LDV) and Vector Doppler Ultrasound (VDUS) point velocity measurements, and wholefield measurements such as Particle Image Velocimetry (PIV), Ultrasound Imaging Velocimetry (UIV), Colour Doppler Ultrasound (CDUS), and Planar Laser Induced Fluorescence (PLIF). Of these methods, the ultrasound techniques can also be used in-vivo, to provide realistic boundary conditions to in-vitro experiments or numerical simulations. In the reviewed work, experimental modelling is mainly used to support computational models, but also in some cases as a tool on its own. It is concluded that, to further advance the utility of computational modelling in vascular access research, a rigorous verification and validation procedure should be adopted. Experimental modelling can play an important role in both in-vitro The final publication is available at Springer via http://dx.doi.org/10.1007/s13239-017-0311-4 2 S. Drost et al.validation, and the quantification of the accuracy, uncertainty, and reproducibility of in-vivo measurement methods.

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“…In addition, Zhe et al [17,18] developed a beam type of floating-element sensor that used differential capacitance detection scheme to measure displacement. Tseng and Lin [19] developed an optical fiber-based method of measuring displacement, and Horowitz et al [20] developed a geometric Moiré interferometry method of measuring displacement. In the latter study, the unsteady properties were characterized, which revealed a sensor resonant frequency at 1.7 kHz and a noise floor shear level at 6.2 mPa.…”

Section: Introductionmentioning

confidence: 99%