152 research outputs found
Advanced-Canopy-Atmosphere-Soil Algorithm (ACASA model) for estimating mass and energy fluxes
No full textThere is a recognized need to improve land surface models that simulate mass and energy fluxes
between terrestrial ecosystems and atmosphere. In particular, long-term land planning strategies at local
and regional scales require better understanding of agricultural ecosystem capacity to exchange CO2and water. One of the more elaborate models for flux modelling is the Advanced Canopy-Atmosphere-Soil
Algorithm (ACASA) model (Pyles et al., 2000), which provides micro-scale and regional-scale
fluxes. The ACASA model allows for characterization of energy and carbon fluxes. It is a higher-order
closure model used to estimate fluxes and profiles of heat, water vapor, carbon and momentum within
and above canopy using third-order closure equations. It also estimates turbulent profiles of velocity,
temperature, humidity within and above canopy. The ACASA model estimates CO2fluxes using a
combination of Ball-Berry and Farquhar equations. In addition, the effects of water stress on stomata,
transpiration and CO2assimilation are considered. The model was mainly used over dense canopies
(Pyles et al. 2000, 2003) in the past, so the aim of this work was to test the ACASA model over a
sparse canopy for estimating mass and energy fluxes, comparing model output with field measurements
taken over a vineyard located in Montalcino, Tuscany, Italy
AN ANALYSIS OF VALUE-ADDED AGRICULTURAL EXPORTS TO MIDDLE-INCOME DEVELOPING COUNTRIES: THE CASE OF WHEAT AND BEEF PRODUCTS
No full textThis study determined probable future directions in U.S. value-added agricultural exports to middle-income developing countries (MIDCs) under the assumption of continued income growth. Import share equations for U.S. bulk, semi-processed and value-added wheat or beef products, as a percent of total U.S. wheat or beef product exports to each MIDC, were econometrically estimated using the ordinary least squares (OLS) technique. The empirical results indicate that in most MIDCs, increases in real per capita income have negative effects on the import share of processed wheat products while having positive effects on the import share of bulk wheat. However, import shares of U.S. processed beef products are likely to increase with income growth in most MIDCs.International Relations/Trade,
Compensational behavior of three debris-flow fans in southern Colorado
No full text2014 Spring.Includes illustrations (some color), color maps.Includes bibliographical references (pages 45-46).Building an understanding of debris-flow avulsion tendencies would deepen the understanding of sediment transport modes and inform hazard assessment and mitigation by suggesting the paths of future debris-flows following channel avulsion. To explore these tendencies, three debris fans were selected in southern Colorado for compensational analysis. Compensation refers to the tendency of discrete flow events to preferentially fill topographic lows following channel avulsions (Straub et al., 2009). By assessing the level of compensational behavior within each fan, it was possible to predict, in a general sense, the avulsion tendency. To assess the level of compensation present within each fan, outcrops where either natural or anthropogenic processes had acted to expose strata were located and subdivided into discrete depositional units. The relative size and positioning of each unit was used in a statistical analysis of compensation within each debris fan system. The result of this analysis was a single number, referred to as the modified compensation index (Straub and Pyles, 2012), for each outcrop which varied from 0.63 to 1.03 across the three exposures. Values close to 0.5 represent intermediate avulsion tendencies within a fan, while results approaching 1.0 reflect more compensational behavior. Values less than 0.5 correspond to anti-compensational, or aggradational behavior which is rarely observed in nature (Straub and Pyles, 2012). The results of this project include a correlation assessment of modified compensation indices versus other data collected in the field and interpreted in the lab including: the percent stream flow material by area, percent clay by mass in the matrix, percent by volume of pebble-sized clasts, percent by volume of cobble-sized and greater clasts, maximum observed unit thickness, observed unit width, unit width-to-thickness ratio, fractional outcrop distance from the fan apex, and absolute distance of outcrop from the fan apex. It is intended that engineers and developers may predict the level of compensation and therefore the avulsion habits of a debris fan by observing a combination of these readily measurable parameters. As a result, mitigation methods could be selected and arranged more strategically to account for the likely direction of debris-flow avulsions in the future
Towards a planning decision support system for low-carbon urban development
No full textThe flows of carbon and energy produced by urbanized areas represent one of the aspects of urban sustainability that can have an important impact on climate change. For this reason, in recent years the quantitative estimation of the so-called urban metabolism components has increasingly attracted the attention of researchers from different fields. On the other hand, it has been well recognized that the structure and design of future urban development can significantly affect the flows of material and energy exchanged by an urban area with its surroundings. In this context, the paper discusses a software framework able to estimate the carbon exchanges accounting for alternative scenarios which can influence urban development. The modelling system is based on four main components: (i) a Cellular Automata model for the simulation of the urban land-use dynamics; (ii) a transportation model, able to estimate the variation of the transportation network load and (iii) the ACASA (Advanced Canopy-Atmosphere-Soil Algorithm) model which was tightly coupled with the (iv) mesoscale weather model WRF for the estimation of the relevant urban metabolism components. An in-progress application to the city of Florence is presented and discussed
Urban metabolism and climate change: A planning support system
No full textPatterns of urban development influence flows of material and energy within urban settlements and exchanges with its surrounding. In recent years the quantitative estimation of the components of the so-called urban metabolism has increasingly attracted the attention of researchers from different fields. To contribute to this effort we developed a modelling framework for estimating the carbon exchanges together with sensible and latent heat fluxes and air temperature in relation to alternative land-use scenarios. The framework bundles three components: (i) a Cellular Automata model for the simulation of the urban land-use dynamics; (ii) a transportation model for estimating the variation of the transportation network load and (iii) the Advanced Canopy-Atmosphere-Soil Algorithm (ACASA) model tightly coupled with the mesoscale weather forecasting model WRF. We present and discuss the results of an example application on the City of Florence.Patterns of urban development influence flows of material and energy within urban settlements and exchanges with its surrounding. In recent years the quantitative estimation of the components of the so-called urban metabolism has increasingly attracted the attention of researchers from different fields. To contribute to this effort we developed a modelling framework for estimating the carbon exchanges together with sensible and latent heat fluxes and air temperature in relation to alternative land-use scenarios. The framework bundles three components: (i) a Cellular Automata model for the simulation of the urban land-use dynamics; (ii) a transportation model for estimating the variation of the transportation network load and (iii) the Advanced Canopy-Atmosphere-Soil Algorithm (ACASA) model tightly coupled with the mesoscale weather forecasting model WRF. We present and discuss the results of an example application on the City of Florence
Stratigraphic architecture of slope deposits associated with prograding margins, Sobrarbe Formation: Ainsa Basin, Spain
No full textIncludes bibliographical references.Includes illustrations, maps
Architectural elements and facies distribution along an actively growing deepwater basin margin, Eocene Morillo Stratigraphic Unit, Ainsa Basin, Spain
No full textIncludes bibliographical references.Includes illustrations
Controlling protein assembly on mineral surface with designed interfaces
No full textThesis (Ph.D.)--University of Washington, 2019Proteins that interface with inorganic crystals have critical functions in biology. For example, biomineralization proteins form hard tissues such as bone, abalone shell, and sponge spicules, and mineral binding proteins in iron-reducing bacteria transfer electrons to their environment. While the atomistic details of natural protein-mineral interfaces remain largely unknown, inspiration for design can be gleaned from ice-binding proteins that display arrays of amino-acid side-chains spaced in regular intervals that geometrically match the ice lattice surface. Collaborators and I hypothesized that a similar lattice-matching approach could be used to design interactions between proteins and minerals. Using designed-helical repeat proteins engineered to adsorb and assemble on the mica (001) surface, we demonstrated this approach can control protein assembly on the surface of an inorganic crystal
Advanced-Canopy-Atmosphere-Soil Algorithm (ACASA model) for estimating mass and energy fluxes
No full textThere is a recognized need to improve land surface models that simulate mass and energy fluxes
between terrestrial ecosystems and atmosphere. In particular, long-term land planning strategies at local
and regional scales require better understanding of agricultural ecosystem capacity to exchange CO2
and water. One of the more elaborate models for flux modelling is the Advanced Canopy-Atmosphere-Soil
Algorithm (ACASA) model (Pyles et al., 2000), which provides micro-scale and regional-scale
fluxes. The ACASA model allows for characterization of energy and carbon fluxes. It is a higher-order
closure model used to estimate fluxes and profiles of heat, water vapor, carbon and momentum within
and above canopy using third-order closure equations. It also estimates turbulent profiles of velocity,
temperature, humidity within and above canopy. The ACASA model estimates CO2 fluxes using a
combination of Ball-Berry and Farquhar equations. In addition, the effects of water stress on stomata,
transpiration and CO2 assimilation are considered. The model was mainly used over dense canopies
(Pyles et al. 2000, 2003) in the past, so the aim of this work was to test the ACASA model over a
sparse canopy for estimating mass and energy fluxes, comparing model output with field measurements
taken over a vineyard located in Montalcino, Tuscany, Italy
[Photograph 2012.201.B1036.0186]
No full textPhotograph used for a story in the Daily Oklahoman newspaper. Caption: "Stephan Pyles of Dallas conducted a four-hour cooking class on Southwestern cuisine at Classic Gourmet. He was assisted by partner John Dayton and five staff members from Routh Street Cafe.
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