1,666 research outputs found

    Let\u27s Keep What We Have Until We Get More to Keep

    Get PDF

    Some New Developments in Road Construction and Maintenance

    Get PDF

    The Highway Game - Offense vs. Defense

    Get PDF

    Proposal for a study of computer mapping of terrain using multispectral data from ERTS-A for the Yellowstone National Park test site

    Get PDF
    The author has identified the following significant results. A terrain map of Yellowstone National Park showed plant community types and other classes of ground cover in what is basically a wild land. The map comprised 12 classes, six of which were mapped with accuracies of 70 to 95%. The remaining six classes had spectral reflectances that overlapped appreciably, and hence, those were mapped less accurately. Techniques were devised for quantitatively comparing the recognition map of the park with control data acquired from ground inspection and from analysis of sidelooking radar images, a thermal IR mosaic, and IR aerial photos of several scales. Quantitative analyses were made in ten 40 sq km test areas. Comparison mechanics were performed by computer with the final results displayed on line printer output. Forested areas were mapped by computer using ERTS data for less than 1/4 the cost of the conventional forest mapping technique for topographic base maps

    Introducing the concept of Potential Aerosol Mass (PAM)

    No full text
    International audiencePotential Aerosol Mass (PAM) can be defined as the maximum aerosol mass that the oxidation of precursor gases produces. In the measurement, all precursor gases are rapidly oxidized with extreme amounts of oxidants to low volatility compounds, resulting in the aerosol formation. Oxidation occurs in a small, simple, flow-through chamber that has a short residence time and is irradiated with ultraviolet light. The amount of the oxidants ozone (O3), hydroxyl (OH), and hydroperoxyl (HO2) were measured directly and can be controlled by varying the UV light and the relative humidity. Maximum values were 40 ppmv for O3, 500 pptv for OH, and 4 ppbv for HO2. The oxidant amounts are 100 to 1000 times troposphere values, but the ratios OH/O3 and HO2/OH are similar to troposphere values. The aerosol production mechanism and the aerosol mass yield were studied for several controlling variables, such as temperature, relative humidity, oxidant concentration, presence of nitrogen oxides (NOx), precursor gas composition and amount, and the presence of acidic seed aerosol. The measured secondary organic aerosol (SOA) yield of several natural and anthropogenic volatile organic compounds and a mixture of hydrocarbons in the PAM chamber were similar to those obtained in large, batch-style environmental chambers. This PAM method is being developed for measuring potential aerosol mass in the atmosphere, but is also useful for examining SOA processes in the laboratory and in environmental chambers

    Introducing the concept of Potential Aerosol Mass (PAM)

    Get PDF
    International audiencePotential Aerosol Mass (PAM) can be defined as the maximum aerosol mass that the oxidation of precursor gases produces. In the measurement, all precursor gases are rapidly oxidized with extreme amounts of oxidants to low volatility compounds, resulting in the aerosol formation. Oxidation occurs in a small, simple, flow-through chamber that has a short residence time and is irradiated with ultraviolet light. The amount of the oxidants ozone (O3), hydroxyl (OH), and hydroperoxyl (HO2) were measured directly and can be controlled by varying the UV light and the relative humidity. Maximum values were 40 ppmv for O3 500 pptv for OH, and 4 ppbv for HO2. The oxidant amounts are 100 to 1000 times troposphere values, but the ratios OH/O3 and HO2/OH are similar to troposphere values. The aerosol production mechanism and the aerosol mass yield were studied for several controlling variables, such as temperature, relative humidity, oxidant concentration, presence of nitrogen oxides (NOx), precursor gas composition and amount, and the presence of acidic seed aerosol. The measured secondary organic aerosol (SOA) yield of several natural and anthropogenic volatile organic compounds and a mixture of hydrocarbons in the PAM chamber were similar to those obtained in large, batch-style environmental chambers. This PAM method is being developed for measuring potential aerosol mass in the atmosphere, but is also useful for examining SOA processes in the laboratory and in environmental chambers

    Boys' and girls' clubs

    Get PDF
    "Club work is based on sound principles and has come to stay. It is supported by federal and state aid as a definite form of agricultural extension work. Boys and girls on the farm are aided in their work and every possible advantage is extended to flt them, for better living and "to improve country life." It is proper in this connection to mention that club work has received special recognition from the State Superintendent of Public Instruction. On Pages 124-126 of the last Annual School Report will be found a general statement of this movement. On Pages 122 and 124 of the last State Course of Study will b.e found the . details of some of the projects. In the first county campaign which had as an aim to acquaint patrons, pupils and teachers with the nature and purpose of Boys' and Girls' Clubs, the state superintendent took personal part and gave sanction to the work. So far as known no other state has given stronger recognition to club work than Missouri."--Page 3

    Introducing the concept of Potential Aerosol Mass (PAM)

    Get PDF
    La Constitución Política de Colombia de 1991 intentó consolidar un proceso de cambio cultural tendiente a modernizar la administración pública haciendo más eficaces, eficientes y económicos los procedimientos de gobierno y por consiguiente, el desempeño de los empleados oficiales
    corecore