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Data Fusion for Global Estimation of Forest Characteristics From Sparse Lidar Data

A new approach automatically produces a hierarchical set of image segmentations for detailed analysis of forest data. This lidar data fusion approach is based on associating samples from sparse lidar data with groups of region objects determined by a unique image segmentation approach, HSeg (Hierar - chical Segmentation). This segmentation approach, which was previously developed by co-innovator James Tilton, is ideal for this application because HSeg automatically produces a hierarchical set of image segmentations, i.e., a set of several image segmentations of the same image at different levels of detail in which the segmentations at coarser levels of detail can be produced from simple merges of regions at finer levels of detail. This enables a simple approach for selecting an appropriate level of segmentation detail. HSeg also automatically classifies the spatially continuous region objects into region classes, through a tight intertwining of region growing segmentation, which produces spatially connected region objects, with non-adjacent region object aggregation, which groups sets of region objects together into region classes. No other practical, operational image segmentation approach has this tight integration of region growing, object finding with non-adjacent region aggregation. HSeg produces image segmentations with high spatial fidelity — enabled by the tight intertwining of region growing segmentation with non-adjacent region object aggregation.

Posted in: Information Sciences, Data Acquisition, Briefs

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Transportable Instrumentation Package for In-Vehicle On-Road Data Acquisition

This portable data acquisition system is a viable alternative to first developing a fully instrumented test vehicle. The study of driver behavior can provide a wealth of information that can be useful in the design of automobiles including active safety features and functions. There may be differences in driver behavior, as reflected in driver state, and these differences may be confounded by a driver’s condition. Much can be learned from studies that look at driver state and condition to answer questions such as how vehicle features and functionality could be designed to complement the driver’s capabilities and limitations in the vehicle. Also, a better understanding could be gained to determine how, or if at all, a safety feature’s characteristics should be modified to accommodate a driver’s condition.

Posted in: Physical Sciences, Data Acquisition, Briefs

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Virtual Testing of High Lift Systems

Virtual testing serves as an additional, equivalent means of testing versus existing, established physical means of compliance. For aircraft system certification, a huge amount of testing is required to guarantee safe, robust, and error-free behavior under all operating and environmental conditions. Typically, these tests on the system level are performed on physical test benches (left, in figure) where all the relevant components including actuators, sensors, and control computer are integrated. Due to the increasing complexity of systems on the one hand, and drastically reduced development times on the other, virtual testing has become one of the solutions to overcome this challenge.

Posted in: Information Sciences, Data Acquisition, Briefs

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Integrated PEMFC Flow Field Design for Gravity-Independent Passive Water Removal

The design solves safety as well as reliability issues. A gravity-independent PEM (proton exchange membrane) fuel cell stack has been developed that will operate at high-pressure H2 and O2 conditions with the requirement for relatively modest H2 and O2 gas circulation. Until now, in order to get higher efficiency, excess reactant gas flow was required to prevent water slug formation in gas channels, thus reducing fuel cell performance. In addition, this excess gas flow is typically supported by mechanical pumps and/or a high-pressure ejector system. All of these in a closed space environment contributed to potential safety as well as reliability issues due to the potential failure of mechanical pumps and ejectors.

Posted in: Manufacturing & Prototyping, Briefs

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Metal-Assisted Fabrication of Biodegradable Porous Silicon Nanostructures

Silicon nanostructures are fabricated from single-crystal silicon by an electroless chemical etch process. Porous silicon nanowires are fabricated by two-step, metal-assisted electroless chemical etching of p-type or n-type silicon wafers. This method, in combination with nanolithography or nanopatterning, can be applied to fabricate porous silicon nanostructures of different shapes and sizes, such as nanorods, nanobelts, nanostrips, and nanochains. The specific resistivity of the silicon substrate, and composition of the etching solution, determine the porosity and pore size or lack thereof of the resulting nanostructures. Silicon doping, type of metal catalyst, concentrations of H2O2, and solvent all affect the formation of porous nanostructures at various resistivity ranges of silicon. A phase diagram summarizing the relation of porosification and doping, metal, concentrations of H2O2, and solvent can be generated. In this innovation, high-aspect-ratio porous silicon nanostructures, such as those previously mentioned, were fabricated from single-crystal silicon by an electroless chemical etch process. A metal film, metal nanofeatures, or metal nanoparticles were coated on the silicon substrate first, and a solution of HF and hydrogen peroxide was then used to anisotropically etch the silicon to form the porous silicon nanostructures. Up to hundreds of micron-long high-aspect-ratio porous silicon nanostructures can be fabricated, and the patterns of the cross-section of porous silicon structures can be controlled by photolithography, nanolithography, or nanoparticle-assisted patterning. The porosity is related to the resistivity range of the silicon substrate, the metal catalysts, the chemical concentration, and the additive solvent. The fabricated porous silicon nanostructure is biodegradable, and the degradation time can be controlled by surface treatments. Porous silicon nanowires can be fabricated with a two-step process. A nanostructured metal layer can be deposited on a silicon substrate by an electroless chemical deposition or electrochemical deposition. This step determines the shape of the final nanowires. Alternatively, metal nanoparticles can be spun on the silicon surface to form a metal layer, or a metal layer can be physically or chemically deposited on the silicon through a nanopatterned mask. The metal-coated silicon can be etched in a solution of HF, water, and H2O2 to produce porous silicon nanowires. Solvent can be added to the solution to modulate the features of the porous silicon nanowires. This work was done by Mauro Ferrari, Xuewu Liu, and Ciro Chappini of the University of Texas Health Science Center at Houston for Johnson Space Center. For further information, contact the JSC Innovation Partnerships Office at (281) 483-3809. In accordance with Public Law 96-517, the contractor has elected to retain title to this invention. Inquiries concerning rights for its commercial use should be addressed to:   The University of Texas  Health and Science Center at Houston  Office of Technology Management  7000 Fannin Street, Suite 720  Houston, TX 77030 MSC-24690-1

Posted in: Manufacturing & Prototyping, Semiconductors & ICs, Briefs

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Post-Growth, In Situ Adhesion of Carbon Nanotubes to a Substrate for Robust CNT Cathodes

This technology can be used down-hole in oil wells, and in high-temperature, high-pressure, corrosive environments in the automotive industry. The field emission electron sources using carbon nanotubes (CNTs) are being targeted for low-power vacuum microelectronic applications for harshenvironment operation (high temperature, pressure, and corrosive atmosphere). While CNTs have demonstrated excellent properties in terms of low threshold field, low-power operation, and high current densities, one problem with vacuum electronic applications is poor adhesion of CNTs to the substrate on which they are synthesized. The chemical vapor deposition (CVD) process used to grow CNTs on silicon or other metallic substrates using an iron catalyst with a thin oxide diffusion barrier layer has consistently provided reproducible growth. The CNTs are only surface- adhering in these cases, and are easily removed from the surface with the application of minor forces — typically pressures of 20 to 60 kPa. This causes catastrophic failures of CNT field emitters since the applied field could exceed the adhesion strength of CNTs to the substrate.

Posted in: Manufacturing & Prototyping, Briefs

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Thermal Mechanical Preparation of Glass Spheres

The forming process allows a very wide variety of material to be processed into spheres. Samples of lunar regolith have included small glass spheres. Most literature has suggested the small spheres were formed by meteorite impacts. The resulting transformation of kinetic energy to thermal energy caused the lunar surface to melt. The process yielded glass spheres. Recreating a meteorite impact that yields glass spheres is very challenging. Furthermore, the melting temperature of certain minerals on the Moon precludes the use of standard thermal techniques.

Posted in: Manufacturing & Prototyping, Briefs

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