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On-Orbit Multi-Field Wavefront Control With a Kalman Filter

A document describes a multi-field wavefront control (WFC) procedure for the James Webb Space Telescope (JWST) on-orbit optical telescope element (OTE) fine-phasing using wavefront measurements at the NIRCam pupil. The control is applied to JWST primary mirror (PM) segments and secondary mirror (SM) simultaneously with a carefully selected ordering. Through computer simulations, the multi-field WFC procedure shows that it can reduce the initial system wavefront error (WFE), as caused by random initial system misalignments within the JWST fine-phasing error budget, from a few dozen um to below 50 nm across the entire NIRCam Field of View, and the WFC procedure is also computationally stable as the Monte-Carlo simulations indicate.

Posted in: Briefs, TSP

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Advanced Particle Separation Technology Uses Coriolis Force and Specific Gravity

This technology selectively separates fine and small particles that have a desired particle size range by using the particles’ specific gravity and their various sedimentation rates in a rotating vessel of vibrating liquid. By adjusting the frequency and amplitude of the vibration, and by controlling the rotation of the vessel, the technology can enlarge what may be a close-to-equal settling ratio for small particles of high specific gravity and larger particles of low specific gravity, so as to achieve accurate separation by cross-sectional dimension or specific gravity.

Posted in: Techs for License

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Reducing Free Fatty Acids in Frying Oil

A food manufacturer is looking for a technology to extend the usability of its frying oils; specifically, technologies to reduce the formation of free fatty acids (FFA) during frying. The company seeks to change or control chemical reaction of hydrolysis without changing water content of the food itself. Taste, smell, color, and texture must not be affected. If the solution is an ingredient, the product must be natural and food-grade; synthesized compounds will not be evaluated. Respond to this TechNeed at: Email: nasatech@yet2.com Phone: 781-972-0600

Posted in: NASA Tech Needs

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Image Processing for Controlling a Robot or Quality Inspection

A company seeks technologies that may be applicable to automated assembly lines, including a robot to use image processing to select and pick up small parts from a bin using a pin several millimeters in diameter. The image processing technology should be general-purpose and highly versatile to allow the techniques to be applied to many different situations. The required picking speed is several seconds. Possible solution areas are 3D medical imagery and automated surgical equipment. Respond to this TechNeed at: Email: nasatech@yet2.com Phone: 781-972-0600

Posted in: NASA Tech Needs

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Multichannel Monitor-Stabilizer for Injection-Locked Lasers

Temp Tracker and Temp Tracker 12 ch (single-channel and 12-channel versions) programs are designed for use with an atomic gravity gradiometer. They support the stable operation of the injection-locked slave laser(s) in an autonomous regime. Due to changes of environmental conditions and aging, slave lasers tend to drift from the locking range and need to be relocked. This program checks the injection-locking range for each slave laser and re-centers them with respect to the master lasers, if needed. The master laser is assumed to be locked at an absorption line of Cs.

Posted in: Photonics, Briefs, TSP

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Self-Quenching Single-Photon Detector

The detector has applications in nuclear physics instruments, spectroscopy, night-vision devices, and biological instrumentation. The self-quenching single-photon detector exhibits unique avalanching behaviors. It can automatically quench each of the Geiger mode avalanche events occurring inside the detector, can maintain the capability over a broad bias range, and can output explicit pulses with virtually constant and high value gain.

Posted in: Photonics, Briefs

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Reducing Temperature Effects in Optical Resonator Sensors

Influences of temperature fluctuations are suppressed by factors of about 105. A differential-frequency measurement technique has been devised to reduce the spurious contributions of temperature fluctuations to determinations of physical quantities from readings of optical resonator and interferometric sensors. The technique is applicable mainly to sensors in the form of whispering-gallery mode (WGM) optical resonators. The evanescent electromagnetic fields of such resonators interact with their environments, such that their resonance frequencies change in response to environmental changes (e.g., a change in the index of refraction of the surrounding medium) that one seeks to measure. The resonance frequencies also vary significantly with temperature, with consequent introduction of errors and uncertainties and, hence, effective loss of sensitivity to changes in quantities other than temperature that one seeks to determine.

Posted in: Photonics, Briefs, TSP

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