12,830 research outputs found

    Detection and Characterization of Stress Symptoms in Forest Vegetation

    Get PDF
    Techniques used at the Pacific Southwest Forest and Range Experiment Station to detect advanced and previsual symptoms of vegetative stress are discussed. Stresses caused by bark beetles in coniferous stands of timber are emphasized because beetles induce stress more rapidly than most other destructive agents. Bark beetles are also the most damaging forest insects in the United States. In the work on stress symptoms, there are two primary objectives: (1) to learn the best combination of films, scales, and filters to detect and locate injured trees from aircraft and spacecraft, and (2) to learn if stressed trees can be detected before visual symptoms of decline occur. Equipment and techniques used in a study of the epidemic of the Black Hills bark beetle are described

    Multispectral photography for earth resources

    Get PDF
    A guide for producing accurate multispectral results for earth resource applications is presented along with theoretical and analytical concepts of color and multispectral photography. Topics discussed include: capabilities and limitations of color and color infrared films; image color measurements; methods of relating ground phenomena to film density and color measurement; sensitometry; considerations in the selection of multispectral cameras and components; and mission planning

    NASA Tech Briefs Index, 1977, volume 2, numbers 1-4

    Get PDF
    Announcements of new technology derived from the research and development activities of NASA are presented. Abstracts, and indexes for subject, personal author, originating center, and Tech Brief number are presented for 1977

    Nationwide forestry applications program. Ten-Ecosystem Study (TES) site 6, Fort Yukon, Alaska

    Get PDF
    The author has identified the following significant results. Analysis of the processing results has led to the following conclusions: (1) LANDSAT imagery was a reliable resource for the stratification of level 2 forest features (softwood, hardwood, tundra, and water). These features can be classified with an accuracy of 72.4 percent + or - 5.9 percent at the 90 percent confidence level. (2) Training fields selected for signature development from only 10 percent of the area did not adequately and efficiently cover the class variability for the entire area. (3) Derived regression transformations were ineffective in recovering the loss of level 1 forest proportions and level 2 softwood and hardwood proportions

    Synthetic aperture radar/LANDSAT MSS image registration

    Get PDF
    Algorithms and procedures necessary to merge aircraft synthetic aperture radar (SAR) and LANDSAT multispectral scanner (MSS) imagery were determined. The design of a SAR/LANDSAT data merging system was developed. Aircraft SAR images were registered to the corresponding LANDSAT MSS scenes and were the subject of experimental investigations. Results indicate that the registration of SAR imagery with LANDSAT MSS imagery is feasible from a technical viewpoint, and useful from an information-content viewpoint

    Profile approach for recognition of three-dimensional magnetic structures

    Full text link
    We propose an approach for low-dimensional visualisation and classification of complex topological magnetic structures formed in magnetic materials. Within the approach one converts a three-dimensional magnetic configuration to a vector containing the only components of the spins that are parallel to the z axis. The next crucial step is to sort the vector elements in ascending or descending order. Having visualized profiles of the sorted spin vectors one can distinguish configurations belonging to different phases even with the same total magnetization. For instance, spin spiral and paramagnetic states with zero total magnetic moment can be easily identified. Being combined with a simplest neural network our profile approach provides a very accurate phase classification for three-dimensional magnets characterized by complex multispiral states even in the critical areas close to phases transitions. By the example of the skyrmionic configurations we show that profile approach can be used to separate the states belonging to the same phase

    A Module Experimental Process System Development Unit (MEPSDU)

    Get PDF
    Design work for a photovoltaic module, fabricated using single crystal silicon dendritic web sheet material, resulted in the identification of surface treatment to the module glass superstrate which improved module efficiencies. A final solar module environmental test, a simulated hailstone impact test, was conducted on full size module superstrates to verify that the module's tempered glass superstrate can withstand specified hailstone impacts near the corners and edges of the module. Process sequence design work on the metallization process selective, liquid dopant investigation, dry processing, and antireflective/photoresist application technique tasks, and optimum thickness for Ti/Pd are discussed. A noncontact cleaning method for raw web cleaning was identified and antireflective and photoresist coatings for the dendritic webs were selected. The design of a cell string conveyor, an interconnect feed system, rolling ultrasonic spot bonding heat, and the identification of the optimal commercially available programmable control system are also discussed. An economic analysis to assess cost goals of the process sequence is also given

    Design characteristics unique to the flexographic printing process

    Get PDF
    The flexographic printing process has been used for package printing applications since the late 1800\u27s. Recent improvements in the flexographic technology have enabled flexographic printers to compete in new market areas that have historically been served by roto-gravure or offset lithographic printing. Occurring simultaneously with the flexographic printing improvements has been the infusion of personal computer-based graphic design capabilities. Designers can optimize quality only when they understand the strengths and weaknesses of the printing process that will be used to mass produce their design. Desktop design capabilities and the need for flexographic print quality to match or exceed lithographic and roto-gravure print quality are both factors that accentuate the need to understand the process in an effort to create a design that will be of high quality when printed flexographically. Designing package graphics for the flexographic process is unique for a number of reasons, ( the master image carrier (printing plate) is significantly different from roto-gravure and offset lithography, the inks used in flexography are significantly different form those used in gravure) and a wider assortment of substrates may be printed by the flexographic process than by the offset lithographic process. Each substrate has its own printing characteristics. This thesis will inform those who may be interested in designing for flexographic printing of the unique considerations that should be addressed when designing a package graphic for flexographic printing. Considerations specifically addressed are; variable repeat length capabilities, reverse-side printing, trapping, typography halftones and dot-gain screen ruling and substrate, step-and-repeat and flexographic plate elongation
    corecore