94 research outputs found

    Nebraska Agricultural Water Management Demonstration Network (NAWMDN): Integrating Research and Extension/Outreach

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    Maximizing the net benefits of irrigated plant production through appropriately designed agricultural water management programs is of growing importance in Nebraska, and other western and Midwestern states, because many areas are involved in management and policy changes to conserve irrigation water. In Nebraska, farmers are being challenged to practice conservation methods and use water resources more efficiently while meeting plant water requirements and maintaining high yields. Another challenge Nebraska experiences in it\u27s approximately 3.5‐million‐ha irrigated lands is limited adoption of newer technologies/tools to help farmers better manage irrigation, conserve water and energy, and increase plant water use efficiency. In 2005, the Nebraska Agricultural Water Management Demonstration Network (NAWMDN or Network) was formed from an interdisciplinary team of partners including the Natural Resources Districts (NRD); USDA‐NRCS; farmers from south central, northeast, west central, and western Nebraska; crop consultants; and University of Nebraska‐Lincoln faculty. The main goal of the Network is to enable the transfer of high quality research‐based information to Nebraskans through a series of demonstration projects established in farmers\u27 fields and implement newer tools and technologies to address and enhance plant water use efficiency, water conservation, and reduce energy consumption for irrigation. The demonstration projects are supported by the scientifically‐based field research and evaluation projects conducted at the University of Nebraska‐Lincoln, South Central Agricultural Laboratory located near Clay Center, Nebraska. The Network was formed with only 15 farmers as collaborators in only one of the 23 NRDs in 2005. As of late 2009, the number of active collaborators has increased to over 300 in 12 NRDs and 35 of 93 counties. The Network is impacting both water and energy conservation due to farmers adopting information and newer technologies for irrigation management. The NAWMDN is helping participants to improve irrigation management and efficiency by monitoring plant growth stages and development, soil moisture, and crop evapotranspiration. As a result, they are reducing irrigation water application amounts and associated energy savings is leading to greater profitability to participating farmers. This article describes the goals and objectives of the Network, technical and educational components, operational functions, and procedures used in the NAWMDN. The quantitative impacts in terms of water and energy conservation are reported

    NEBRASKA AGRICULTURAL WATER MANAGEMENT DEMONSTRATION NETWORK (NAWMDN): INTEGRATING RESEARCH AND EXTENSION/OUTREACH

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    Maximizing the net benefits of irrigated plant production through appropriately designed agricultural water management programs is of growing importance in Nebraska, and other western and Midwestern states, because many areas are involved in management and policy changes to conserve irrigation water. In Nebraska, farmers are being challenged to practice conservation methods and use water resources more efficiently while meeting plant water requirements and maintaining high yields. Another challenge Nebraska experiences in it\u27s approximately 3.5‐million‐ha irrigated lands is limited adoption of newer technologies/tools to help farmers better manage irrigation, conserve water and energy, and increase plant water use efficiency. In 2005, the Nebraska Agricultural Water Management Demonstration Network (NAWMDN or Network) was formed from an interdisciplinary team of partners including the Natural Resources Districts (NRD); USDA‐NRCS; farmers from south central, northeast, west central, and western Nebraska; crop consultants; and University of Nebraska‐Lincoln faculty. The main goal of the Network is to enable the transfer of high quality research‐based information to Nebraskans through a series of demonstration projects established in farmers\u27 fields and implement newer tools and technologies to address and enhance plant water use efficiency, water conservation, and reduce energy consumption for irrigation. The demonstration projects are supported by the scientifically‐based field research and evaluation projects conducted at the University of Nebraska‐Lincoln, South Central Agricultural Laboratory located near Clay Center, Nebraska. The Network was formed with only 15 farmers as collaborators in only one of the 23 NRDs in 2005. As of late 2009, the number of active collaborators has increased to over 300 in 12 NRDs and 35 of 93 counties. The Network is impacting both water and energy conservation due to farmers adopting information and newer technologies for irrigation management. The NAWMDN is helping participants to improve irrigation management and efficiency by monitoring plant growth stages and development, soil moisture, and crop evapotranspiration. As a result, they are reducing irrigation water application amounts and associated energy savings is leading to greater profitability to participating farmers. This article describes the goals and objectives of the Network, technical and educational components, operational functions, and procedures used in the NAWMDN. The quantitative impacts in terms of water and energy conservation are reported

    Surface Energy Budgets of Arctic Tundra During Growing Season

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    This study analyzed summer observations of diurnal and seasonal surface energy budgets across several monitoring sites within the Arctic tundra underlain by permafrost. In these areas, latent and sensible heat fluxes have comparable magnitudes, and ground heat flux enters the subsurface during short summer intervals of the growing period, leading to seasonal thaw. The maximum entropy production (MEP) model was tested as an input and parameter parsimonious model of surface heat fluxes for the simulation of energy budgets of these permafrost‐underlain environments. Using net radiation, surface temperature, and a single parameter characterizing the thermal inertia of the heat exchanging surface, the MEP model estimates latent, sensible, and ground heat fluxes that agree closely with observations at five sites for which detailed flux data are available. The MEP potential evapotranspiration model reproduces estimates of the Penman‐Monteith potential evapotranspiration model that requires at least five input meteorological variables (net radiation, ground heat flux, air temperature, air humidity, and wind speed) and empirical parameters of surface resistance. The potential and challenges of MEP model application in sparsely monitored areas of the Arctic are discussed, highlighting the need for accurate measurements and constraints of ground heat flux.Plain Language SummaryGrowing season latent and sensible heat fluxes are nearly equal over the Arctic permafrost tundra regions. Persistent ground heat flux into the subsurface layer leads to seasonal thaw of the top permafrost layer. The maximum energy production model accurately estimates the latent, sensible, and ground heat flux of the surface energy budget of the Arctic permafrost regions.Key PointThe MEP model is parsimonious and well suited to modeling surface energy budget in data‐sparse permafrost environmentsPeer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/150560/1/jgrd55584.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/150560/2/jgrd55584_am.pd

    A conformação dos ecomuseus: elementos para compreensão e anålise

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    Apresenta uma histĂłria dos ecomuseus enraizado nos movimentos de folclore e etnografia regional, do final do sĂ©culo XIX atĂ© os dias de hoje, examinando o caso francĂȘs. Explora aspectos em geral menos enfatizados neste campo, tal como a natureza e o papel atribuĂ­do aos acervos e ao patrimĂŽnio cultural e padrĂ”es museogrĂĄticos

    Characterization of aerosols generated by nanosecond laser ablation of an acrylic paint

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    cited By 3This study focuses on particles produced during laser ablation of a green colored acrylic wall paint, which is frequently used in industrial buildings and in particular in nuclear installations. Ablation is carried out with a Nd: YAG laser at a wavelength of 532 nm and a pulse duration of 5 ns, in a cell at ambient pressure and temperature, which is ventilated by filtered air. The number of particles emitted was measured with a Condensation Particle Counter (CPC) and their size with an Engine Exhaust Particle Sizer (or EEPS) for the nanometric range, and an AEROSIZER (for the micrometric range). The mass and shape of particles were determined by sampling on filters as well as on the different impaction plates of a Low-Pressure Impactor (LPI). Two particle populations were detected: a population of aggregates of primary nanoparticles with an electrical mobility diameter ranging from 30 to 150 nm, and a population of spherical submicron particles with an aerodynamic diameter ranging from 400 to 1000 nm. The spherical particles are mainly composed of titanium dioxide, and the aggregates most likely of carbon. The presence of two types of particles with different size distributions, shapes, and chemical compositions, implies that particles originating from the ablation of paint are formed by two different mechanisms: agglomeration in the case of the nanometric aggregates, which is preceded by steps of nucleation, condensation, and coagulation of the primary particles, while the submicron spheres result from a direct ejection mechanism. Copyright © American Association for Aerosol Research

    Influence of carrier gas flow rate, laser repetition rate, and fluence on the size distribution and number of nanoparticles generated per laser shot during paint laser ablation

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    This study focuses on the influence of three operating parameters (gas flow rate, laser repetition rate, and fluence) on the number and size distributions of nanoparticles generated by laser ablation of acrylic paint. These particles, produced by gas-to-particle conversion of vapors generated by polymer vaporization, can have a spherical shape with a 16 nm diameter (called primary particles) but most of them are aggregated primary particles. The most critical parameter is the gas (air) flow rate in the ablation cell. Indeed, the total number of nanoparticles produced per shot increases with the air flow rate, whereas the aggregate size decreases. Indeed, the gas flow rate controls the transit time and the related aggregation duration, which decrease with increasing flow rates. The influence of the air flow rate on the nanoparticle total number produced per shot can be attributed to the evolution of the particle residence time in the setup with the flow rate. In order to validate this point, the setup has been modeled (model based on the Smoluchowski coagulation equations). The model has shown that the primary particle aggregation mainly takes place in a sphere of a few millimetres in diameter. This sphere varies in volume with the laser fluence but does not depend on the air flow rate in the cell. Moreover, the nanoparticle final number per shot does not depend on the primary particle initial number per shot but only on the size of the interaction volume, which is related to laser fluence. Copyright © American Association for Aerosol Research
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