2,935 research outputs found
Large-area, wide-angle, spectrally selective plasmonic absorber
A simple metamaterial-based wide-angle plasmonic absorber is introduced,
fabricated, and experimentally characterized using angle-resolved infrared
spectroscopy. The metamaterials are prepared by nano-imprint lithography, an
attractive low-cost technology for making large-area samples. The matching of
the metamaterial's impedance to that of vacuum is responsible for the observed
spectrally selective "perfect" absorption of infrared light. The impedance is
theoretically calculated in the single-resonance approximation, and the
responsible resonance is identified as a short-range surface plasmon. The
spectral position of the absorption peak (which is as high as 95%) is
experimentally shown to be controlled by the metamaterial's dimensions. The
persistence of "perfect" absorption with variable metamaterial parameters is
theoretically explained. The wide-angle nature of the absorber can be utilized
for sub-diffraction-scale infrared pixels exhibiting spectrally selective
absorption/emissivity.Comment: 7 pages, 6 figures, submitted to Phys. Rev.
Physicochemical Properties and Catalytic Behavior of the Molecular Sieve SSZ-70
SSZ-70 is synthesized using 1,3-bis(isobutyl)imidazolium, 1,3-bis(cyclohexyl)imidazolium, and 1,3-bis(cycloheptyl)imidazolium structure directing agents (SDAs), and the solids obtained are characterized by powder X-ray diffraction (XRD), ^(29)Si magic angle spinning nuclear magnetic resonance (MAS NMR), electron microscopy, nitrogen and hydrocarbon adsorption, and thermogravimetric analyses. The physicochemical properties of SSZ-70 show that it is a new molecular sieve that has similarities to MWW-type materials. The catalytic behavior of SSZ-70 is evaluated through the use of the constraint index (CI) test. Distinct differences in the reactivity between Al-SSZ-70 and SSZ-25 (MWW) are observed and are the consequences of the structural differences between these two molecular sieves
Are There Tradeoffs Between Farm Profitabilty and Environmental Quality in South Dakota\u27s Big Sioux Aquifer Area?; Grain Market Volatility - Is $4.00 Cash Corn Possible in Eastern South Dakota?
Profitability and Nitrate Leaching Effects of Possible Farming Practice and System Changes Over South Dakota\u27s Big Sioux Aquifer: Case Farm No. 2 Summary
The overall goal of the SARE/Water Quality project was to determine whether economic incentives offered by recent environmental provisions of Federal farm program are sufficient to induce Western Corn Belt/Northern Plains farmers in environmentally sensitive areas to adopt sustainable fa practices and systems. To attain this goal, four case farms were chosen involved in this study based on their size, soil types, cropping systems, topography, and management in the Big Sioux Aquifer study area. Case Farm No. 2 is located in Moody County and followed a corn-soybean oats rotation on the acres focused on in the analysis prior to enrollment the Integrated Crop Management (ICM) program. It is a dry-land operation used conventional tillage prior to enrollment in the ICM program. The total operation consists of 1,858 acres, with 710 acres under the ICM program focused on 299 of those ICM acres in our analyses. Lamo and Clamo soils up the majority of the ICM crop acres. These are medium to fine-textured soils overlying a shallow drinking water aquifer
Profitability and Nitrate Leaching Effects of Possible Farming Practice and System Changes Over South Dakota\u27s Big Sioux Aquifer: Case Farm No. 4 Summary
The overall goal of the SARE/Water Quality project was to determine whether economic incentives offered by recent environmental provisions of the Federal farm program are sufficient to induce Western Corn Belt/Northern Great Plains farmers in environmentally sensitive areas to adopt sustainable farming practices and systems. To attain this goal, four case farms were chosen to be involved in this study based on their size, soil types, cropping systems, topography, and management in the Big Sioux Aquifer study area. Case Farm No. 4 is located in Brookings County and followed a continuous corn rotation prior to enrollment in the Water Quality Incentive Program (WQIP). It is an irrigated operation that uses a center-pivot system. Conventional tillage practices are used. The total operation consists of 838 acres, with 213 acres enrolled in the WQIP program. One hundred and fifty of those acres received irrigation management assistance. In one 73-acre field irrigated by a center-pivot system, 66 acres were assumed to be under the center-pivot system and the other 7 acres were assumed to be in the corners of the field where the center-pivot system could not reach. These 7 acres were designated as the set-aside acres for the baseline before scenario. This 73-acre field was focused on in our analyses. The majority of the soils in this field are a combination of coarse-textured (Fordville), and fine-textured (Marysland) soils. Both of these soils overlay a shallow drinking water aquife
Profitability and Nitrate Leaching Effects of Possible Farming Practice and System Changes Over South Dakota\u27s Big Sioux Aquifer: Case Farm No. 3 Summary
The overall goal of the SARE/Water Quality project was to determine whether economic incentives offered by recent environmental provisions of the Federal farm program are sufficient to induce Western Corn Belt/Northern Great Plains farmers in environmentally sensitive areas to adopt sustainable farming practices and systems. To attain this goal, four case farms were chosen to be involved in this study based on their size, soil types, cropping systems, topography, and management in the Big Sioux Aquifer study area. Case Farm No.3 is located in Minnehaha County and has corn, soybeans, oats, alfalfa, and clover. It is a dry-land operation that uses conventional tillage. The total operation consists of 168 acres, with 108 of the acres under the Water Quality Incentive program (WQIP) being focused on in the study. The acres are divided into two separate fields that are managed differently. A corn/soybean rotation is followed on the lower field and inorganic fertilizers were used. The upper field contains two different rotations. One rotation is a corn/oats,clover rotation and the other is a corn/oats,alf/alf/alf/alf/alf rotation. The majority of the soils on the lower field under WQIP are a combination of medium (Brandt), and coarse textured (La Prairie) soils. Both of these soils overlay a shallow drinking water aquifer. The upper field was mostly Moody soils (medium-textured). These soils don\u27t overlay an aquifer, but contribute to the runoff onto the lower field
Profitability and Nitrate Leaching Effects of Possible Farming Practice and System Changes Over South Dakota\u27s Big Sioux Aquifer: Case Farm No. 1 Summary
The overall goal of the SARE/Water Quality project was to determine whether economic incentives offered by recent environmental provisions of the Federal farm program are sufficient to induce Western Corn Belt/Northern Great Plains farmers in environmentally sensitive areas to adopt sustainable farming practices and systems. To attain this goal, four case farms were chosen to be involved in this study based on their size, soil types, cropping systems, topography, and management in the Big Sioux Aquifer study area
Profitability and Nitrate Leaching Effects of Possible Farming Practice and System Changes Over South Dakota\u27s Big Sioux Aquifer: Case Farm No. 1 Summary
The overall goal of the SARE/Water Quality project was to determine whether economic incentives offered by recent environmental provisions of the Federal farm program are sufficient to induce Western Corn Belt/Northern Great Plains farmers in environmentally sensitive areas to adopt sustainable farming practices and systems. To attain this goal, four case farms were chosen to be involved in this study based on their size, soil types, cropping systems, topography, and management in the Big Sioux Aquifer study area
Profitability and Nitrate Leaching Effects of Possible Farming Practice and System Changes Over South Dakota\u27s Big Sioux Aquifer: Case Farm No. 1 Summary
The overall goal of the SARE/Water Quality project was to determine whether economic incentives offered by recent environmental provisions of the Federal farm program are sufficient to induce Western Corn Belt/Northern Great Plains farmers in environmentally sensitive areas to adopt sustainable farming practices and systems. To attain this goal, four case farms were chosen to be involved in this study based on their size, soil types, cropping systems, topography, and management in the Big Sioux Aquifer study area
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