Special Coverage

Technique Provides Security for Multi-Robot Systems
Bringing New Vision to Laser Material Processing Systems
NASA Tests Lasers’ Ability to Transmit Data from Space
Converting from Hydraulic Cylinders to Electric Actuators
Automating Optimization and Design Tasks Across Disciplines
Vibration Tables Shake Up Aerospace and Car Testing
Supercomputer Cooling System Uses Refrigerant to Replace Water
Computer Chips Calculate and Store in an Integrated Unit
Electron-to-Photon Communication for Quantum Computing

Purifying Nucleic Acids From Samples of Extremely Low Biomass

A new method is able to circumvent the bias to which one commercial DNA extraction method falls prey with regard to the lysing of certain types of microbial cells, resulting in a truncated spectrum of microbial diversity. By prefacing the protocol with glass-bead-beating agitation (mechanically lysing a much more encompassing array of cell types and spores), the resulting microbial diversity detection is greatly enhanced.

Posted in: Briefs, Bio-Medical, Medical, Biological sciences, Test procedures
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Adjustable-Viewing-Angle Endoscopic Tool for Skull Base and Brain Surgery

Surgeons could operate more precisely.

The term “Multi-Angle and Rear Viewing Endoscopic tooL” (MARVEL) denotes an auxiliary endoscope, now undergoing development, that a surgeon would use in conjunction with a conventional endoscope to obtain additional perspective. The role of the MARVEL in endoscopic brain surgery would be similar to the role of a mouth mirror in dentistry. Such a tool is potentially useful for in-situ planetary geology applications for the close-up imaging of unexposed rock surfaces in cracks or those not in the direct line of sight.

Posted in: Briefs, TSP, Bio-Medical, Medical, Medical equipment and supplies, Surgical procedures
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UV-Resistant Non-Spore-Forming Bacteria From Spacecraft-Assembly Facilities

Four species of non-spore-forming bacteria collected from clean-room surfaces in spacecraft-assembly facilities could survive doses of ultraviolet (UV) radiation that would suffice to kill most known cultivable bacterial species. In a previous study, high UV resistance was found in spores of the SAFR-032 strain of Bacillus pumilus, as reported in “Ultraviolet-Resistant Bacterial Spores,” NASA Tech Briefs, Vol. 31, No. 9 (September 2007), page 94. These studies are parts of a continuing effort to understand the survival of hardy species of bacteria under harsh conditions, and develop means of sterilizing spacecraft to prevent biocontamination of Mars that could in turn interfere with future life detection missions.

Posted in: Briefs, Bio-Medical, Medical, Environmental protection, Bacteria, Assembling, Radiation
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Near-Field Spectroscopy With Nanoparticles Deposited by AFM

It is not necessary to integrate an AFM with a spectrometer.

An alternative approach to apertureless near- field optical spectroscopy involving an atomic-force microscope (AFM) entails less complexity of equipment than does a prior approach. The alternative approach has been demonstrated to be applicable to apertureless near-field optical spectroscopy of the type using an AFM and surface enhanced Raman scattering (SERS), and is expected to be equally applicable in cases in which infrared or fluorescence spectroscopy is used.

Posted in: Briefs, Physical Sciences, Spectroscopy, Nanomaterials, Test equipment and instrumentation
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Simplified Modeling of Oxidation of Hydrocarbons

Only a few dozen molecular and radical species are included in calculations.

A method of simplified computational modeling of oxidation of hydrocarbons is undergoing development. This is one of several developments needed to enable accurate computational simulation of turbulent, chemically reacting flows. At present, accurate computational simulation of such flows is difficult or impossible in most cases because (1) the numbers of grid points needed for adequate spatial resolution of turbulent flows in realistically complex geometries are beyond the capabilities of typical supercomputers now in use and (2) the combustion of typical hydrocarbons proceeds through decomposition into hundreds of molecular species interacting through thousands of reactions. Hence, the combination of detailed reaction-rate models with the fundamental flow equations yields flow models that are computationally prohibitive. Hence, further, a reduction of at least an order of magnitude in the dimension of reaction kinetics is one of the prerequisites for feasibility of computational simulation of turbulent, chemically reacting flows.

Posted in: Briefs, TSP, Physical Sciences, Computational fluid dynamics, Hydrocarbons
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Hard-X-Ray/Soft-γ-Ray Imaging Sensor Assembly for Astronomy

A pixilated scintillator is coupled with an array of avalanche photodiodes.

An improved sensor assembly has been developed for astronomical imaging at photon energies ranging from 1 to 100 keV. The assembly includes a thallium-doped cesium iodide scintillator divided into pixels and coupled to an array of high-gain avalanche photodiodes (APDs). Optionally, the array of APDs can be operated without the scintillator to detect photons at energies below 15 keV. The array of APDs is connected to compact electronic readout circuitry that includes, among other things, 64 independent channels for detection of photons in various energy ranges, up to a maximum energy of 100 keV, at a count rate up to 3 kHz. The readout signals are digitized and processed by imaging software that performs “on-the-fly” analysis.

Posted in: Briefs, TSP, Physical Sciences, Architecture, Imaging and visualization, Sensors and actuators, Radiation
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Hyperspectral Fluorescence and Reflectance Imaging Instrument

A single system contains spatial-scanning, illumination, and spectral-imaging subsystems.

The system is a single hyperspectral imaging instrument that has the unique capability to acquire both fluorescence and reflectance high-spatial-resolution data that is inherently spatially and spectrally registered. Potential uses of this instrument include plant stress monitoring, counterfeit document detection, biomedical imaging, forensic imaging, and general materials identification.

Posted in: Briefs, Physical Sciences, Imaging and visualization, Test equipment and instrumentation
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Light Collimator and Monitor for a Spectroradiometer

This system handles the optical input and electronic output of two spectrometers.

A system that comprises optical and electronic subsystems has been developed as an infrastructure for a spectroradiometer that measures time- dependent spectral radiance of the daylight sky, in a narrow field of view (having angular width of the order of 1°) centered on the zenith, in several spectral bands in the wavelength range from 0.3 to 2.2 μm. This system is used in conjunction with two commercially available monolithic spectrometers: a silicon-based one for wavelengths from 0.3 to 1.1 μm and a gallium arsenide-based one for wavelengths from 1.05 to 2.2 μm (see figure). The role of this system is to collect the light from the affected region of the sky, collimate the light, deliver the collimated light to the monolithic spectrometers, and process the electronic outputs of the spectrometers.

Posted in: Briefs, Physical Sciences, Electronic equipment, Optics, Test equipment and instrumentation
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Toward Better Modeling of Supercritical Turbulent Mixing

A study was done as part of an effort to develop computational models representing turbulent mixing under thermodynamic supercritical (here, high pressure) conditions. The question was whether the large-eddy simulation (LES) approach, developed previously for atmospheric-pressure compressible-perfect- gas and incompressible flows, can be extended to real-gas non-ideal (including supercritical) fluid mixtures. [In LES, the governing equations are approximated such that the flow field is spatially filtered and sub-grid-scale (SGS) phenomena are represented by models.] The study included analyses of results from direct numerical simulation (DNS) of several such mixing layers based on the Navier-Stokes, total-energy, and conservation-of-chemical-species governing equations.

Posted in: Briefs, Information Sciences, Simulation and modeling, Thermodynamics, Gases
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JPEG 2000 Encoding With Perceptual Distortion Control

The bit rate for a given level of perceptual distortion is minimized.

An alternative approach has been devised for encoding image data in compliance with JPEG 2000, the most recent still-image data- compression standard of the Joint Photographic Experts Group. Heretofore, JPEG 2000 encoding has been implemented by several related schemes classified as rate-based distortion-minimization encoding. In each of these schemes, the end user specifies a desired bit rate and the encoding algorithm strives to attain that rate while minimizing a mean squared error (MSE). While rate-based distortion minimization is appropriate for transmitting data over a limited-bandwidth channel, it is not the best approach for applications in which the perceptual quality of reconstructed images is a major consideration. A better approach for such applications is the present alternative one, denoted perceptual distortion control, in which the encoding algorithm strives to compress data to the lowest bit rate that yields at least a specified level of perceptual image quality.

Posted in: Briefs, TSP, Information Sciences, Data acquisition and handling, Imaging and visualization
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