WorldWideScience

Sample records for models incorporating feedstock

  1. Model feedstock supply processing plants

    Directory of Open Access Journals (Sweden)

    V. M. Bautin

    2013-01-01

    Full Text Available The model of raw providing the processing enterprises entering into vertically integrated structure on production and processing of dairy raw materials, differing by an orientation on achievement of cumulative effect by the integrated structure acting as criterion function which maximizing is reached by optimization of capacities, volumes of deliveries of raw materials and its qualitative characteristics, costs of industrial processing of raw materials and demand for dairy production is developed.

  2. Modeling Sustainable Bioenergy Feedstock Production in the Alps

    Science.gov (United States)

    Kraxner, Florian; Leduc, Sylvain; Kindermann, Georg; Fuss, Sabine; Pietsch, Stephan; Lakyda, Ivan; Serrano Leon, Hernan; Shchepashchenko, Dmitry; Shvidenko, Anatoly

    2016-04-01

    Sustainability of bioenergy is often indicated by the neutrality of emissions at the conversion site while the feedstock production site is assumed to be carbon neutral. Recent research shows that sustainability of bioenergy systems starts with feedstock management. Even if sustainable forest management is applied, different management types can impact ecosystem services substantially. This study examines different sustainable forest management systems together with an optimal planning of green-field bioenergy plants in the Alps. Two models - the biophysical global forest model (G4M) and a techno-economic engineering model for optimizing renewable energy systems (BeWhere) are implemented. G4M is applied in a forward looking manner in order to provide information on the forest under different management scenarios: (1) managing the forest for maximizing the carbon sequestration; or (2) managing the forest for maximizing the harvestable wood amount for bioenergy production. The results from the forest modelling are then picked up by the engineering model BeWhere, which optimizes the bioenergy production in terms of energy demand (power and heat demand by population) and supply (wood harvesting potentials), feedstock harvesting and transport costs, the location and capacity of the bioenergy plant as well as the energy distribution logistics with respect to heat and electricity (e.g. considering existing grids for electricity or district heating etc.). First results highlight the importance of considering ecosystem services under different scenarios and in a geographically explicit manner. While aiming at producing the same amount of bioenergy under both forest management scenarios, it turns out that in scenario (1) a substantially larger area (distributed across the Alps) will need to be used for producing (and harvesting) the necessary amount of feedstock than under scenario (2). This result clearly shows that scenario (2) has to be seen as an "intensification

  3. Feedstock Quality Factor Calibration and Data Model Development

    Energy Technology Data Exchange (ETDEWEB)

    Richard D. Boardman; Tyler L. Westover; Garold L. Gresham

    2010-05-01

    The goal of the feedstock assembly operation is to deliver uniform, quality-assured feedstock materials that will enhance downstream system performance by avoiding problems in the conversion equipment. In order to achieve this goal, there is a need for rapid screening tools and methodologies for assessing the thermochemical quality characteristics of biomass feedstock through the assembly process. Laser-induced breakdown spectroscopy (LIBS) has been identified as potential technique that could allow rapid elemental analyses of the inorganic content of biomass feedstocks; and consequently, would complement the carbohydrate data provided by near-infrared spectrometry (NIRS). These constituents, including Si, K, Ca, Na, S, P, Cl, Mg, Fe and Al, create a number of downstream problems in thermochemical processes. In particular, they reduce the energy content of the feedstock, influence reaction pathways, contribute to fouling and corrosion within systems, poison catalysts, and impact waste streams.

  4. Articulating feedstock delivery device

    Science.gov (United States)

    Jordan, Kevin

    2013-11-05

    A fully articulable feedstock delivery device that is designed to operate at pressure and temperature extremes. The device incorporates an articulating ball assembly which allows for more accurate delivery of the feedstock to a target location. The device is suitable for a variety of applications including, but not limited to, delivery of feedstock to a high-pressure reaction chamber or process zone.

  5. Liquefied Wood as Inexpensive Precursor-Feedstock for Bio-Mediated Incorporation of (R-3-Hydroxyvalerate into Polyhydroxyalkanoates

    Directory of Open Access Journals (Sweden)

    Martin Koller

    2015-09-01

    Full Text Available Liquefied wood (LW prepared in a microwave process was applied as a novel; inexpensive precursor feedstock for incorporation of (R-3-hydroxyvalerate (3HV into polyhydroxyalkanoate (PHA biopolyesters in order to improve the biopolyester’s material quality; Cupriavidus necator was applied as microbial production strain. For proof of concept, pre-experiments were carried out on a shake flask scale using different mixtures of glucose and LW as carbon source. The results indicate that LW definitely acts as a 3HV precursor, but, at the same time, displays toxic effects on C. necator at concentrations exceeding 10 g/L. Based on these findings, PHA biosynthesis under controlled conditions was performed using a fed-batch feeding regime on a bioreactor scale. As major outcome, a poly(3HB-co-0.8%-3HV copolyester was obtained displaying a desired high molar mass of Mw = 5.39 × 105 g/mol at low molar-mass dispersity (ĐM of 1.53, a degree of crystallinity (Xc of 62.1%, and melting temperature Tm (176.3 °C slightly lower than values reported for poly([R]-3-hydroxybutyrate (PHB homopolyester produced by C. necator; thus, the produced biopolyester is expected to be more suitable for polymer processing purposes.

  6. Design, modeling, and analysis of a feedstock logistics system.

    Science.gov (United States)

    Judd, Jason D; Sarin, Subhash C; Cundiff, John S

    2012-01-01

    Given the location of a bio-energy plant for the conversion of biomass to bio-energy, a feedstock logistics system that relies on the use of satellite storage locations (SSLs) for temporary storage and loading of round bales is proposed. Three equipment systems are considered for handling biomass at the SSLs, and they are either placed permanently or are mobile and thereby travel from one SSL to another. A mathematical programming-based approach is utilized to determine SSLs and equipment routes in order to minimize the total cost. The use of a Side-loading Rack System results in average savings of 21.3% over a Densification System while a Rear-loading Rack System is more expensive to operate than either of the other equipment systems. The utilization of mobile equipment results in average savings of 14.8% over the equipment placed permanently. Furthermore, the Densification System is not justifiable for transportation distances less than 81 km. Copyright © 2011 Elsevier Ltd. All rights reserved.

  7. Investigating the impact of biomass quality on near-infrared models for switchgrass feedstocks

    Directory of Open Access Journals (Sweden)

    Lindsey M. Kline

    2015-12-01

    Full Text Available The aim of this study was to determine the impact of incorporating switchgrass samples that have been in long term storage on the development of near-infrared (NIR multivariate calibration models and their predictive capabilities. Stored material contains more variation in their respective spectral signatures due to chemical changes in the bales with storage time. Partial least squares (PLS regression models constructed using NIR spectra of stored switchgrass possessed an instability that interfered with the correlation between the spectral data and measured chemical composition. The models were improved using calibration sample sets of equal parts stored and fresh switchgrass to more accurately predict the chemical composition of stored switchgrass. Acceptable correlation values (rcalibration were obtained using a calibration sample set composed of 25 stored samples and 25 samples of fresh switchgrass for cellulose (0.91, hemicellulose (0.74, total carbohydrates (0.76, lignin (0.98, extractives (0.92, and ash (0.87. Increasing the calibration sample set to 100 samples of equal parts stored to senesced material resulted in statistically increased (p = 0.05 correlations for total carbohydrates (0.89 and ash (0.96. When these models were applied to a separate validation set (equal to 10% of the calibration sample set, high correlation coefficients (r for predicted versus measured constituent content were observed for cellulose (0.94, total carbohydrates (0.98, lignin (0.91, extractives (0.97, and ash (0.90. For optimization of processing economics, the impact of feedstock storage must be investigated for implementation in conversion processes. While NIR is a well-known high-throughput technique for characterization of senesced switchgrass, the selection of appropriate calibration samples and consequent multivariate models must be taken into careful consideration for NIR application in a biomass storage facility for rapid chemical compositional

  8. MODEL BASED BIOMASS SYSTEM DESIGN OF FEEDSTOCK SUPPLY SYSTEMS FOR BIOENERGY PRODUCTION

    Energy Technology Data Exchange (ETDEWEB)

    David J. Muth, Jr.; Jacob J. Jacobson; Kenneth M. Bryden

    2013-08-01

    Engineering feedstock supply systems that deliver affordable, high-quality biomass remains a challenge for the emerging bioenergy industry. Cellulosic biomass is geographically distributed and has diverse physical and chemical properties. Because of this feedstock supply systems that deliver cellulosic biomass resources to biorefineries require integration of a broad set of engineered unit operations. These unit operations include harvest and collection, storage, preprocessing, and transportation processes. Design decisions for each feedstock supply system unit operation impact the engineering design and performance of the other system elements. These interdependencies are further complicated by spatial and temporal variances such as climate conditions and biomass characteristics. This paper develops an integrated model that couples a SQL-based data management engine and systems dynamics models to design and evaluate biomass feedstock supply systems. The integrated model, called the Biomass Logistics Model (BLM), includes a suite of databases that provide 1) engineering performance data for hundreds of equipment systems, 2) spatially explicit labor cost datasets, and 3) local tax and regulation data. The BLM analytic engine is built in the systems dynamics software package PowersimTM. The BLM is designed to work with thermochemical and biochemical based biofuel conversion platforms and accommodates a range of cellulosic biomass types (i.e., herbaceous residues, short- rotation woody and herbaceous energy crops, woody residues, algae, etc.). The BLM simulates the flow of biomass through the entire supply chain, tracking changes in feedstock characteristics (i.e., moisture content, dry matter, ash content, and dry bulk density) as influenced by the various operations in the supply chain. By accounting for all of the equipment that comes into contact with biomass from the point of harvest to the throat of the conversion facility and the change in characteristics, the

  9. Multi-scale process and supply chain modelling: from lignocellulosic feedstock to process and products.

    Science.gov (United States)

    Hosseini, Seyed Ali; Shah, Nilay

    2011-04-06

    There is a large body of literature regarding the choice and optimization of different processes for converting feedstock to bioethanol and bio-commodities; moreover, there has been some reasonable technological development in bioconversion methods over the past decade. However, the eventual cost and other important metrics relating to sustainability of biofuel production will be determined not only by the performance of the conversion process, but also by the performance of the entire supply chain from feedstock production to consumption. Moreover, in order to ensure world-class biorefinery performance, both the network and the individual components must be designed appropriately, and allocation of resources over the resulting infrastructure must effectively be performed. The goal of this work is to describe the key challenges in bioenergy supply chain modelling and then to develop a framework and methodology to show how multi-scale modelling can pave the way to answer holistic supply chain questions, such as the prospects for second generation bioenergy crops.

  10. Compost feedstock characteristics and ratio modelling for organic waste materials co-composting in Malaysia.

    Science.gov (United States)

    Chai, E W; H'ng, P S; Peng, S H; Wan-Azha, W M; Chin, K L; Chow, M J; Wong, W Z

    2013-01-01

    In Malaysia, large amounts of organic materials, which lead to disposal problems, are generated from agricultural residues especially from palm oil industries. Increasing landfill costs and regulations, which limit many types of waste accepted at landfills, have increased the interest in composting as a component of waste management. The objectives of this study were to characterize compost feedstock properties of common organic waste materials available in Malaysia. Thus, a ratio modelling of matching ingredients for empty fruit bunches (EFBs) co-composting using different organic materials in Malaysia was done. Organic waste materials with a C/N ratio of composting. The outcome of this study suggested that the percentage of EFB ranged between 50% and 60%, which is considered as the ideal mixing ratio in EFB co-composting. Conclusively, EFB can be utilized in composting if appropriate feedstock in term of physical and chemical characteristics is coordinated in the co-composting process.

  11. Performance Analysis of an Integrated Fixed Bed Gasifier Model for Different Biomass Feedstocks

    Directory of Open Access Journals (Sweden)

    Sharmina Begum

    2013-12-01

    Full Text Available Energy recovery from biomass by gasification technology has attracted significant interest because it satisfies a key requirement of environmental sustainability by producing near zero emissions. Though it is not a new technology, studies on its integrated process simulation and analysis are limited, in particular for municipal solid waste (MSW gasification. This paper develops an integrated fixed bed gasifier model of biomass gasification using the Advanced System for Process ENngineering (Aspen Plus software for its performance analysis. A computational model was developed on the basis of Gibbs free energy minimization. The model is validated with experimental data of MSW and food waste gasification available in the literature. A reasonable agreement between measured and predicted syngas composition was found. Using the validated model, the effects of operating conditions, namely air-fuel ratio and gasifier temperature, on syngas production are studied. Performance analyses have been done for four different feedstocks, namely wood, coffee bean husks, green wastes and MSWs. The ultimate and proximate analysis data for each feedstock was used for model development. It was found that operating parameters have a significant influence on syngas composition. An air-fuel ratio of 0.3 and gasifier temperature of 700 °C provides optimum performance for a fixed bed gasifier for MSWs, wood wastes, green wastes and coffee bean husks. The developed model can be useful for gasification of other biomasses (e.g., food wastes, rice husks, poultry wastes and sugarcane bagasse to predict the syngas composition. Therefore, the study provides an integrated gasification model which can be used for different biomass feedstocks.

  12. Incorporating Resilience into Dynamic Social Models

    Science.gov (United States)

    2016-07-20

    AFRL-AFOSR-VA-TR-2016-0258 Incorporating Resilience into Dynamic Social Models Eunice Santos UNIVERSITY OF TEXAS AT EL PASO 500 UNIV ST ADMIN BLDG...REPORT TYPE Final Report 3. DATES COVERED (From - To) 3/1/13-12/31/14 4. TITLE AND SUBTITLE Incorporating Resilience into Dynamic Social Models 5a...AVAILABILITY STATEMENT 13. SUPPLEMENTARY NOTES 14. ABSTRACT We propose an overarching framework designed to incorporate various aspects of social resilience

  13. Pricing model for biodiesel feedstock: A case study of Chhattisgarh in India

    International Nuclear Information System (INIS)

    Pohit, Sanjib; Biswas, Pradip Kumar; Kumar, Rajesh; Goswami, Anandajit

    2010-01-01

    Following the global trend, India declared its biofuel policy in which biodiesel, primarily from jatropha, would meet 20% of the diesel demand beginning with 2011-2012. To promote biofuel, Indian government has announced biodiesel purchase price as well as compulsory blending ratio. But, these measures have not worked to create large scale biodiesel production in India. With this backdrop, this paper highlights about the importance of a sound pricing policy focusing on the entire value chain of biodiesel production. The analysis is based on field level data from Chhattisgarh, the leading state in the production of jatropha. Such a sound pricing policy has to deal with the prices of feedstock, by-products and final product like biodiesel. It would also have to reflect on the business model of production of biodiesel. The simulation exercises in our model shows that the business returns from the production of biodiesel and the minimum support price (MSP) of the feedstock for biodiesel (i.e. jatropha seeds in this case) are sensitive to various parameters like seed yields, technological efficiency, by product and petro-diesel prices. An effective price policy framework has to consider all these factors to create a platform for sustainable biodiesel production in India. - Research highlights: → India's biodiesel program began way back in 2003. → Success is limited. → Effective policy frame is missing. → Paper proposed to address the same with field level observation.

  14. Multi-scale process and supply chain modelling: from lignocellulosic feedstock to process and products

    Science.gov (United States)

    Hosseini, Seyed Ali; Shah, Nilay

    2011-01-01

    There is a large body of literature regarding the choice and optimization of different processes for converting feedstock to bioethanol and bio-commodities; moreover, there has been some reasonable technological development in bioconversion methods over the past decade. However, the eventual cost and other important metrics relating to sustainability of biofuel production will be determined not only by the performance of the conversion process, but also by the performance of the entire supply chain from feedstock production to consumption. Moreover, in order to ensure world-class biorefinery performance, both the network and the individual components must be designed appropriately, and allocation of resources over the resulting infrastructure must effectively be performed. The goal of this work is to describe the key challenges in bioenergy supply chain modelling and then to develop a framework and methodology to show how multi-scale modelling can pave the way to answer holistic supply chain questions, such as the prospects for second generation bioenergy crops. PMID:22482032

  15. Incorporating groundwater flow into the WEPP model

    Science.gov (United States)

    William Elliot; Erin Brooks; Tim Link; Sue Miller

    2010-01-01

    The water erosion prediction project (WEPP) model is a physically-based hydrology and erosion model. In recent years, the hydrology prediction within the model has been improved for forest watershed modeling by incorporating shallow lateral flow into watershed runoff prediction. This has greatly improved WEPP's hydrologic performance on small watersheds with...

  16. Nest survival modelling using a multi-species approach in forests managed for timber and biofuel feedstock

    Science.gov (United States)

    Loman, Zachary G.; Monroe, Adrian; Riffell, Samuel K.; Miller, Darren A.; Vilella, Francisco; Wheat, Bradley R.; Rush, Scott A.; Martin, James A.

    2018-01-01

    Switchgrass (Panicum virgatum) intercropping is a novel forest management practice for biomass production intended to generate cellulosic feedstocks within intensively managed loblolly pine‐dominated landscapes. These pine plantations are important for early‐successional bird species, as short rotation times continually maintain early‐successional habitat. We tested the efficacy of using community models compared to individual surrogate species models in understanding influences on nest survival. We analysed nest data to test for differences in habitat use for 14 bird species in plots managed for switchgrass intercropping and controls within loblolly pine (Pinus taeda) plantations in Mississippi, USA.We adapted hierarchical models using hyper‐parameters to incorporate information from both common and rare species to understand community‐level nest survival. This approach incorporates rare species that are often discarded due to low sample sizes, but can inform community‐level demographic parameter estimates. We illustrate use of this approach in generating both species‐level and community‐wide estimates of daily survival rates for songbird nests. We were able to include rare species with low sample size (minimum n = 5) to inform a hyper‐prior, allowing us to estimate effects of covariates on daily survival at the community level, then compare this with a single‐species approach using surrogate species. Using single‐species models, we were unable to generate estimates below a sample size of 21 nests per species.Community model species‐level survival and parameter estimates were similar to those generated by five single‐species models, with improved precision in community model parameters.Covariates of nest placement indicated that switchgrass at the nest site (forest stand level increased daily nest survival.Synthesis and applications. Community models represent a viable method for estimating community nest survival rates and effects of

  17. Nest survival modelling using a multi-species approach in forests managed for timber and biofuel feedstock

    Science.gov (United States)

    Loman, Zachary G.; Monroe, Adrian; Riffell, Samuel K.; Miller, Darren A.; Vilella, Francisco; Wheat, Bradley R.; Rush, Scott A.; Martin, James A.

    2018-01-01

    Switchgrass (Panicum virgatum) intercropping is a novel forest management practice for biomass production intended to generate cellulosic feedstocks within intensively managed loblolly pine‐dominated landscapes. These pine plantations are important for early‐successional bird species, as short rotation times continually maintain early‐successional habitat. We tested the efficacy of using community models compared to individual surrogate species models in understanding influences on nest survival. We analysed nest data to test for differences in habitat use for 14 bird species in plots managed for switchgrass intercropping and controls within loblolly pine (Pinus taeda) plantations in Mississippi, USA.We adapted hierarchical models using hyper‐parameters to incorporate information from both common and rare species to understand community‐level nest survival. This approach incorporates rare species that are often discarded due to low sample sizes, but can inform community‐level demographic parameter estimates. We illustrate use of this approach in generating both species‐level and community‐wide estimates of daily survival rates for songbird nests. We were able to include rare species with low sample size (minimum n = 5) to inform a hyper‐prior, allowing us to estimate effects of covariates on daily survival at the community level, then compare this with a single‐species approach using surrogate species. Using single‐species models, we were unable to generate estimates below a sample size of 21 nests per species.Community model species‐level survival and parameter estimates were similar to those generated by five single‐species models, with improved precision in community model parameters.Covariates of nest placement indicated that switchgrass at the nest site (<4 m) reduced daily nest survival, although intercropping at the forest stand level increased daily nest survival.Synthesis and applications. Community models represent a viable

  18. Synthesis of biodiesel from a model waste oil feedstock using a carbon-based solid acid catalyst: reaction and separation.

    Science.gov (United States)

    Shu, Qing; Nawaz, Zeeshan; Gao, Jixian; Liao, Yuhui; Zhang, Qiang; Wang, Dezheng; Wang, Jinfu

    2010-07-01

    A solid acid catalyst that can keep high activity and stability is necessary when low cost feedstocks are utilized for biodiesel synthesis because the reaction medium contains a large amount of water. Three solid acid catalysts were prepared by the sulfonation of carbonized vegetable oil asphalt and petroleum asphalt. The structure of these catalysts was characterized by a variety of techniques. A new process that used the coupling of the reaction and separation was employed, which greatly improved the conversion of cottonseed oil (triglyceride) and free fatty acids (FFA) when a model waste oil feedstock was used. The vegetable oil asphalt-based catalyst showed the highest catalytic activity. This was due to the high density and stability of its acid sites, its loose irregular network, its hydrophobicity that prevented the hydration of -OH species, and large pores that provided more acid sites for the reactants. Copyright (c) 2010 Elsevier Ltd. All rights reserved.

  19. Comparative feedstock analysis in Setaria viridis L. as a model for C4 bioenergy grasses and Panicoid crop species

    Directory of Open Access Journals (Sweden)

    Carloalberto ePetti

    2013-06-01

    Full Text Available Second generation feedstocks for bioethanol will likely include a sizable proportion of perennial C4 grasses, principally in the Panicoideae clade. The Panicoideae contain agronomically important annual grasses including Zea mays L. (maize, Sorghum bicolor (L. Moench (sorghum, and Saccharum officinarum L. (sugar cane as well as promising second generation perennial feedstocks including Miscanthus x giganteus and Panicum virgatum L. (switchgrass. The underlying complexity of these polyploid grass genomes is a major limitation for their direct manipulation and thus driving a need for rapidly cycling comparative model. Setaria viridis (green millet is a rapid cycling C4 Panicoid grass with a relatively small and sequenced diploid genome and abundant seed production. Stable, transient and protoplast transformation technologies have also been developed for S. viridis making it a potentially excellent model for other C4 bioenergy grasses. Here, the lignocellulosic feedstock composition, cellulose biosynthesis inhibitor (CBI response and saccharification dynamics of S. viridis are compared with the annual s00orghum and maize and the perennial switchgrass bioenergy crops as a baseline study into the applicability for translational research. A genome-wide systematic investigation of the cellulose synthase-A (CesA genes was performed identifying eight candidate sequences. Two-developmental stages; a metabolically active young tissue and b metabolically plateaued (mature material are examined to compare biomass performance metrics.

  20. Incorporating neurophysiological concepts in mathematical thermoregulation models

    Science.gov (United States)

    Kingma, Boris R. M.; Vosselman, M. J.; Frijns, A. J. H.; van Steenhoven, A. A.; van Marken Lichtenbelt, W. D.

    2014-01-01

    Skin blood flow (SBF) is a key player in human thermoregulation during mild thermal challenges. Various numerical models of SBF regulation exist. However, none explicitly incorporates the neurophysiology of thermal reception. This study tested a new SBF model that is in line with experimental data on thermal reception and the neurophysiological pathways involved in thermoregulatory SBF control. Additionally, a numerical thermoregulation model was used as a platform to test the function of the neurophysiological SBF model for skin temperature simulation. The prediction-error of the SBF-model was quantified by root-mean-squared-residual (RMSR) between simulations and experimental measurement data. Measurement data consisted of SBF (abdomen, forearm, hand), core and skin temperature recordings of young males during three transient thermal challenges (1 development and 2 validation). Additionally, ThermoSEM, a thermoregulation model, was used to simulate body temperatures using the new neurophysiological SBF-model. The RMSR between simulated and measured mean skin temperature was used to validate the model. The neurophysiological model predicted SBF with an accuracy of RMSR thermoregulation models can be equipped with SBF control functions that are based on neurophysiology without loss of performance. The neurophysiological approach in modelling thermoregulation is favourable over engineering approaches because it is more in line with the underlying physiology.

  1. Incorporating incorporating economic models into seasonal pool conservation planning

    Science.gov (United States)

    Freeman, Robert C.; Bell, Kathleen P.; Calhoun, Aram J.K.; Loftin, Cyndy

    2012-01-01

    Massachusetts, New Jersey, Connecticut, and Maine have adopted regulatory zones around seasonal (vernal) pools to conserve terrestrial habitat for pool-breeding amphibians. Most amphibians require access to distinct seasonal habitats in both terrestrial and aquatic ecosystems because of their complex life histories. These habitat requirements make them particularly vulnerable to land uses that destroy habitat or limit connectivity (or permeability) among habitats. Regulatory efforts focusing on breeding pools without consideration of terrestrial habitat needs will not ensure the persistence of pool-breeding amphibians. We used GIS to combine a discrete-choice, parcel-scale economic model of land conversion with a landscape permeability model based on known habitat requirements of wood frogs (Lithobates sylvaticus) in Maine (USA) to examine permeability among habitat elements for alternative future scenarios. The economic model predicts future landscapes under different subdivision open space and vernal pool regulatory requirements. Our model showed that even “no build” permit zones extending 76 m (250 ft) outward from the pool edge were insufficient to assure permeability among required habitat elements. Furthermore, effectiveness of permit zones may be inconsistent due to interactions with other growth management policies, highlighting the need for local and state planning for the long-term persistence of pool-breeding amphibians in developing landscapes.

  2. Coupling hydrothermal liquefaction and anaerobic digestion for energy valorization from model biomass feedstocks.

    Science.gov (United States)

    Posmanik, Roy; Labatut, Rodrigo A; Kim, Andrew H; Usack, Joseph G; Tester, Jefferson W; Angenent, Largus T

    2017-06-01

    Hydrothermal liquefaction converts food waste into oil and a carbon-rich hydrothermal aqueous phase. The hydrothermal aqueous phase may be converted to biomethane via anaerobic digestion. Here, the feasibility of coupling hydrothermal liquefaction and anaerobic digestion for the conversion of food waste into energy products was examined. A mixture of polysaccharides, proteins, and lipids, representing food waste, underwent hydrothermal processing at temperatures ranging from 200 to 350°C. The anaerobic biodegradability of the hydrothermal aqueous phase was examined through conducting biochemical methane potential assays. The results demonstrate that the anaerobic biodegradability of the hydrothermal aqueous phase was lower when the temperature of hydrothermal processing increased. The chemical composition of the hydrothermal aqueous phase affected the anaerobic biodegradability. However, no inhibition of biodegradation was observed for most samples. Combining hydrothermal and anaerobic digestion may, therefore, yield a higher energetic return by converting the feedstock into oil and biomethane. Copyright © 2017 Elsevier Ltd. All rights reserved.

  3. Modeling state-level soil carbon emission factors under various scenarios for direct land use change associated with United States biofuel feedstock production

    International Nuclear Information System (INIS)

    Kwon, Ho-Young; Mueller, Steffen; Dunn, Jennifer B.; Wander, Michelle M.

    2013-01-01

    Current estimates of life cycle greenhouse gas emissions of biofuels produced in the US can be improved by refining soil C emission factors (EF; C emissions per land area per year) for direct land use change associated with different biofuel feedstock scenarios. We developed a modeling framework to estimate these EFs at the state-level by utilizing remote sensing data, national statistics databases, and a surrogate model for CENTURY's soil organic C dynamics submodel (SCSOC). We estimated the forward change in soil C concentration within the 0–30 cm depth and computed the associated EFs for the 2011 to 2040 period for croplands, grasslands or pasture/hay, croplands/conservation reserve, and forests that were suited to produce any of four possible biofuel feedstock systems [corn (Zea Mays L)-corn, corn–corn with stover harvest, switchgrass (Panicum virgatum L), and miscanthus (Miscanthus × giganteus Greef et Deuter)]. Our results predict smaller losses or even modest gains in sequestration for corn based systems, particularly on existing croplands, than previous efforts and support assertions that production of perennial grasses will lead to negative emissions in most situations and that conversion of forest or established grasslands to biofuel production would likely produce net emissions. The proposed framework and use of the SCSOC provide transparency and relative simplicity that permit users to easily modify model inputs to inform biofuel feedstock production targets set forth by policy. -- Highlights: ► We model regionalized feedstock-specific United States soil C emission factors. ► We simulate soil C changes from direct land use change associated with biofuel feedstock production. ► Corn, corn-stover, and perennial grass biofuel feedstocks grown in croplands maintain soil C levels. ► Converting grasslands to bioenergy crops risks soil C loss. ► This modeling framework yields more refined soil C emissions than national-level emissions

  4. Lignocellulosic feedstock resource assessment

    Energy Technology Data Exchange (ETDEWEB)

    Rooney, T.

    1998-09-01

    This report provides overall state and national information on the quantity, availability, and costs of current and potential feedstocks for ethanol production in the United States. It characterizes end uses and physical characteristics of feedstocks, and presents relevant information that affects the economic and technical feasibility of ethanol production from these feedstocks. The data can help researchers focus ethanol conversion research efforts on feedstocks that are compatible with the resource base.

  5. Incorporating direct marketing activity into latent attrition models

    NARCIS (Netherlands)

    Schweidel, David A.; Knox, George

    2013-01-01

    When defection is unobserved, latent attrition models provide useful insights about customer behavior and accurate forecasts of customer value. Yet extant models ignore direct marketing efforts. Response models incorporate the effects of direct marketing, but because they ignore latent attrition,

  6. Modelling the Peak Elongation of Nylon6 and Fe Powder Based Composite Wire for FDM Feedstock Filament

    Science.gov (United States)

    Garg, Harish Kumar; Singh, Rupinder

    2017-10-01

    In the present work, to increase the application domain of fused deposition modelling (FDM) process, Nylon6-Fe powder based composite wire has been prepared as feed stock filament. Further for smooth functioning of feed stock filament without any change in the hardware and software of the commercial FDM setup, the mechanical properties of the newly prepared composite wire must be comparable/at par to the existing material i.e. ABS, P-430. So, keeping this in consideration; an effort has been made to model the peak elongation of in house developed feedstock filament comprising of Nylon6 and Fe powder (prepared on single screw extrusion process) for commercial FDM setup. The input parameters of single screw extruder (namely: barrel temperature, temperature of the die, speed of the screw, speed of the winding machine) and rheological property of material (melt flow index) has been modelled with peak elongation as the output by using response surface methodology. For validation of model the result of peak elongation obtained from the model equation the comparison was made with the results of actual experimentation which shows the variation of ±1 % only.

  7. A Financial Market Model Incorporating Herd Behaviour.

    Science.gov (United States)

    Wray, Christopher M; Bishop, Steven R

    2016-01-01

    Herd behaviour in financial markets is a recurring phenomenon that exacerbates asset price volatility, and is considered a possible contributor to market fragility. While numerous studies investigate herd behaviour in financial markets, it is often considered without reference to the pricing of financial instruments or other market dynamics. Here, a trader interaction model based upon informational cascades in the presence of information thresholds is used to construct a new model of asset price returns that allows for both quiescent and herd-like regimes. Agent interaction is modelled using a stochastic pulse-coupled network, parametrised by information thresholds and a network coupling probability. Agents may possess either one or two information thresholds that, in each case, determine the number of distinct states an agent may occupy before trading takes place. In the case where agents possess two thresholds (labelled as the finite state-space model, corresponding to agents' accumulating information over a bounded state-space), and where coupling strength is maximal, an asymptotic expression for the cascade-size probability is derived and shown to follow a power law when a critical value of network coupling probability is attained. For a range of model parameters, a mixture of negative binomial distributions is used to approximate the cascade-size distribution. This approximation is subsequently used to express the volatility of model price returns in terms of the model parameter which controls the network coupling probability. In the case where agents possess a single pulse-coupling threshold (labelled as the semi-infinite state-space model corresponding to agents' accumulating information over an unbounded state-space), numerical evidence is presented that demonstrates volatility clustering and long-memory patterns in the volatility of asset returns. Finally, output from the model is compared to both the distribution of historical stock returns and the market

  8. A Financial Market Model Incorporating Herd Behaviour.

    Directory of Open Access Journals (Sweden)

    Christopher M Wray

    Full Text Available Herd behaviour in financial markets is a recurring phenomenon that exacerbates asset price volatility, and is considered a possible contributor to market fragility. While numerous studies investigate herd behaviour in financial markets, it is often considered without reference to the pricing of financial instruments or other market dynamics. Here, a trader interaction model based upon informational cascades in the presence of information thresholds is used to construct a new model of asset price returns that allows for both quiescent and herd-like regimes. Agent interaction is modelled using a stochastic pulse-coupled network, parametrised by information thresholds and a network coupling probability. Agents may possess either one or two information thresholds that, in each case, determine the number of distinct states an agent may occupy before trading takes place. In the case where agents possess two thresholds (labelled as the finite state-space model, corresponding to agents' accumulating information over a bounded state-space, and where coupling strength is maximal, an asymptotic expression for the cascade-size probability is derived and shown to follow a power law when a critical value of network coupling probability is attained. For a range of model parameters, a mixture of negative binomial distributions is used to approximate the cascade-size distribution. This approximation is subsequently used to express the volatility of model price returns in terms of the model parameter which controls the network coupling probability. In the case where agents possess a single pulse-coupling threshold (labelled as the semi-infinite state-space model corresponding to agents' accumulating information over an unbounded state-space, numerical evidence is presented that demonstrates volatility clustering and long-memory patterns in the volatility of asset returns. Finally, output from the model is compared to both the distribution of historical stock

  9. Incorporating territory compression into population models

    NARCIS (Netherlands)

    Ridley, J; Komdeur, J; Sutherland, WJ; Sutherland, William J.

    The ideal despotic distribution, whereby the lifetime reproductive success a territory's owner achieves is unaffected by population density, is a mainstay of behaviour-based population models. We show that the population dynamics of an island population of Seychelles warblers (Acrocephalus

  10. A MODEL FOR INCORPORATING SPECIALIST NURSE ...

    African Journals Online (AJOL)

    2009-09-15

    Sep 15, 2009 ... In this study, the development of a model is regarded as being consistent with middle-range theory generation (George 2002:6), which, in turn, guides the education practice of specialist nurses. According to Smith and Liehr,. [m]iddle range theory can be defined as a set of related ideas that are focused on ...

  11. Incorporating published univariable associations in diagnostic and prognostic modeling

    NARCIS (Netherlands)

    T.P.A. Debray (Thomas); H. Koffijberg (Hendrik); D. Lu (Difei); Y. Vergouwe (Yvonne); E.W. Steyerberg (Ewout); K.G.M. Moons (Karel)

    2012-01-01

    textabstractBackground: Diagnostic and prognostic literature is overwhelmed with studies reporting univariable predictor-outcome associations. Currently, methods to incorporate such information in the construction of a prediction model are underdeveloped and unfamiliar to many researchers. Methods.

  12. Incorporating model uncertainty into optimal insurance contract design

    OpenAIRE

    Pflug, G.; Timonina-Farkas, A.; Hochrainer-Stigler, S.

    2017-01-01

    In stochastic optimization models, the optimal solution heavily depends on the selected probability model for the scenarios. However, the scenario models are typically chosen on the basis of statistical estimates and are therefore subject to model error. We demonstrate here how the model uncertainty can be incorporated into the decision making process. We use a nonparametric approach for quantifying the model uncertainty and a minimax setup to find model-robust solutions. The method is illust...

  13. EVALUATION OF BIOMASS AND COAL CO-GASIFICATION OF BRAZILIAN FEEDSTOCK USING A CHEMICAL EQUILIBRIUM MODEL

    Directory of Open Access Journals (Sweden)

    R. Rodrigues

    Full Text Available Abstract Coal and biomass are energy sources with great potential for use in Brazil. Coal-biomass co-gasification enables the combination of the positive characteristics of each fuel, besides leading to a cleaner use of coal. The present study evaluates the potential of co-gasification of binary coal-biomass blends using sources widely available in Brazil. This analysis employs computational simulations using a reliable thermodynamic equilibrium model. Favorable operational conditions at high temperatures are determined in order to obtain gaseous products suitable for energy cogeneration and chemical synthesis. This study shows that blends with biomass ratios of 5% and equivalence ratios ≤ 0.3 lead to high cold gas efficiencies. Suitable gaseous products for chemical synthesis were identified at biomass ratios ≤ 35% and moisture contents ≥ 40%. Formation of undesirable nitrogen and sulfur compounds was also analyzed.

  14. True dose from incorporated activities. Models for internal dosimetry

    International Nuclear Information System (INIS)

    Breustedt, B.; Eschner, W.; Nosske, D.

    2012-01-01

    The assessment of doses after incorporation of radionuclides cannot use direct measurements of the doses, as for example dosimetry in external radiation fields. The only observables are activities in the body or in excretions. Models are used to calculate the doses based on the measured activities. The incorporated activities and the resulting doses can vary by more than seven orders of magnitude between occupational and medical exposures. Nevertheless the models and calculations applied in both cases are similar. Since the models for the different applications have been developed independently by ICRP and MIRD different terminologies have been used. A unified terminology is being developed. (orig.)

  15. Incorporating parametric uncertainty into population viability analysis models

    Science.gov (United States)

    McGowan, Conor P.; Runge, Michael C.; Larson, Michael A.

    2011-01-01

    Uncertainty in parameter estimates from sampling variation or expert judgment can introduce substantial uncertainty into ecological predictions based on those estimates. However, in standard population viability analyses, one of the most widely used tools for managing plant, fish and wildlife populations, parametric uncertainty is often ignored in or discarded from model projections. We present a method for explicitly incorporating this source of uncertainty into population models to fully account for risk in management and decision contexts. Our method involves a two-step simulation process where parametric uncertainty is incorporated into the replication loop of the model and temporal variance is incorporated into the loop for time steps in the model. Using the piping plover, a federally threatened shorebird in the USA and Canada, as an example, we compare abundance projections and extinction probabilities from simulations that exclude and include parametric uncertainty. Although final abundance was very low for all sets of simulations, estimated extinction risk was much greater for the simulation that incorporated parametric uncertainty in the replication loop. Decisions about species conservation (e.g., listing, delisting, and jeopardy) might differ greatly depending on the treatment of parametric uncertainty in population models.

  16. Incorporating agricultural land cover in conceptual rainfall runoff models

    Science.gov (United States)

    Euser, Tanja; Hrachowitz, Markus; Winsemius, Hessel; Savenije, Hubert

    2015-04-01

    Incorporating spatially variable information is a frequently discussed option to increase the performance of (semi) distributed conceptual rainfall runoff models. One of the methods to do this is by using these spatially variable information to delineate Hydrological Response Units (HRUs) within a catchment. This study tests whether the incorporation of an additional agricultural HRU in a conceptual hydrological model can better reflect the spatial differences in runoff generation and therefore improve the simulation of the wetting phase in autumn. The study area is the meso-scale Ourthe catchment in Belgium. A previous study in this area showed that spatial patterns in runoff generation were already better represented by incorporation of a wetland and a hillslope HRU, compared to a lumped model structure. The influences which are considered by including an agriculture HRU are increased drainage speed due to roads, plough pans and increased infiltration excess overland flow (drainage pipes area only limited present), and variable vegetation patterns due to sowing and harvesting. In addition, the vegetation is not modelled as a static resistance towards evaporation, but the Jarvis stress functions are used to increase the realism of the modelled transpiration; in land-surface models the Jarvis stress functions are already often used for modelling transpiration. The results show that an agricultural conceptualisation in addition to wetland and hillslope conceptualisations leads to small improvements in the modelled discharge. However, the influence is larger on the representation of spatial patterns and the modelled contributions of different HRUs to the total discharge.

  17. Incorporating Responsiveness to Marketing Efforts When Modeling Brand Choice

    NARCIS (Netherlands)

    D. Fok (Dennis); Ph.H.B.F. Franses (Philip Hans); R. Paap (Richard)

    2001-01-01

    textabstractIn this paper we put forward a brand choice model which incorporates responsiveness to marketing efforts as a form of structural heterogeneity. We introduce two latent segments of households. The households in the first segment are assumed to respond to marketing efforts while households

  18. "Violent Intent Modeling: Incorporating Cultural Knowledge into the Analytical Process

    Energy Technology Data Exchange (ETDEWEB)

    Sanfilippo, Antonio P.; Nibbs, Faith G.

    2007-08-24

    While culture has a significant effect on the appropriate interpretation of textual data, the incorporation of cultural considerations into data transformations has not been systematic. Recognizing that the successful prevention of terrorist activities could hinge on the knowledge of the subcultures, Anthropologist and DHS intern Faith Nibbs has been addressing the need to incorporate cultural knowledge into the analytical process. In this Brown Bag she will present how cultural ideology is being used to understand how the rhetoric of group leaders influences the likelihood of their constituents to engage in violent or radicalized behavior, and how violent intent modeling can benefit from understanding that process.

  19. How to incorporate generic refraction models into multistatic tracking algorithms

    Science.gov (United States)

    Crouse, D. F.

    The vast majority of literature published on target tracking ignores the effects of atmospheric refraction. When refraction is considered, the solutions are generally tailored to a simple exponential atmospheric refraction model. This paper discusses how arbitrary refraction models can be incorporated into tracking algorithms. Attention is paid to multistatic tracking problems, where uncorrected refractive effects can worsen track accuracy and consistency in centralized tracking algorithms, and can lead to difficulties in track-to-track association in distributed tracking filters. Monostatic and bistatic track initialization using refraction-corrupted measurements is discussed. The results are demonstrated using an exponential refractive model, though an arbitrary refraction profile can be substituted.

  20. Statistical evaluation and modeling of cheap substrate-based cultivation medium of Chlorella vulgaris to enhance microalgae lipid as new potential feedstock for biolubricant.

    Science.gov (United States)

    Mohammad Mirzaie, M A; Kalbasi, M; Mousavi, S M; Ghobadian, B

    2016-05-18

    Chlorella vulgaris (C. vulgaris) microalga was investigated as a new potential feedstock for the production of biodegradable lubricant. In order to enhance microalgae lipid for biolubricant production, mixotrophic growth of C. vulgaris was optimized using statistical analysis of Plackett-Burman (P-B) and response surface methodology (RSM). A cheap substrate-based medium of molasses and corn steep liquor (CSL) was used instead of expensive mineral salts to reduce the total cost of microalgae production. The effects of molasses and CSL concentration (cheap substrates) and light intensity on the growth of microalgae and their lipid content were analyzed and modeled. Designed models by RSM showed good compatibility with a 95% confidence level when compared to the cultivation system. According to the models, optimal cultivation conditions were obtained with biomass productivity of 0.123 g L(-1) day(-1) and lipid dry weight of 0.64 g L(-1) as 35% of dry weight of C. vulgaris. The extracted microalgae lipid presented useful fatty acid for biolubricant production with viscosities of 42.00 cSt at 40°C and 8.500 cSt at 100°C, viscosity index of 185, flash point of 185°C, and pour point of -6°C. These properties showed that microalgae lipid could be used as potential feedstock for biolubricant production.

  1. Assessing Potential Air Pollutant Emissions from Agricultural Feedstock Production using MOVES

    Energy Technology Data Exchange (ETDEWEB)

    Eberle, Annika [National Renewable Energy Laboratory (NREL), Golden, CO (United States); Warner, Ethan [National Renewable Energy Laboratory (NREL), Golden, CO (United States); Zhang, Yi Min [National Renewable Energy Laboratory (NREL), Golden, CO (United States); Inman, Daniel J [National Renewable Energy Laboratory (NREL), Golden, CO (United States); Carpenter Petri, Alberta C [National Renewable Energy Laboratory (NREL), Golden, CO (United States); Heath, Garvin A [National Renewable Energy Laboratory (NREL), Golden, CO (United States); Hettinger, Dylan J [National Renewable Energy Laboratory (NREL), Golden, CO (United States); Bhatt, Arpit H [National Renewable Energy Laboratory (NREL), Golden, CO (United States)

    2018-03-29

    Biomass feedstock production is expected to grow as demand for biofuels and bioenergy increases. The change in air pollutant emissions that may result from large-scale biomass supply has implications for local air quality and human health. We developed spatially explicit emissions inventories for corn grain and six cellulosic feedstocks through the extension of the National Renewable Energy Laboratory's Feedstock Production Emissions to Air Model (FPEAM). These inventories include emissions of seven pollutants (nitrogen oxides, ammonia, volatile organic compounds, particulate matter, sulfur oxides, and carbon monoxide) generated from biomass establishment, maintenance, harvest, transportation, and biofuel preprocessing activities. By integrating the EPA's MOtor Vehicle Emissions Simulator (MOVES) into FPEAM, we created a scalable framework to execute county-level runs of the MOVES-Onroad model for representative counties (i.e., those counties with the largest amount of cellulosic feedstock production in each state) on a national scale. We used these results to estimate emissions from the on-road transportation of biomass and combined them with county-level runs of the MOVES-Nonroad model to estimate emissions from agricultural equipment. We also incorporated documented emission factors to estimate emissions from chemical application and the operation of drying equipment for feedstock processing, and used methods developed by the EPA and the California Air Resources Board to estimate fugitive dust emissions. The model developed here could be applied to custom equipment budgets and is extensible to accommodate additional feedstocks and pollutants. Future work will also extend this model to analyze spatial boundaries beyond the county-scale (e.g., regional or sub-county levels).

  2. Incorporating nitrogen fixing cyanobacteria in the global biogeochemical model HAMOCC

    Science.gov (United States)

    Paulsen, Hanna; Ilyina, Tatiana; Six, Katharina

    2015-04-01

    Nitrogen fixation by marine diazotrophs plays a fundamental role in the oceanic nitrogen and carbon cycle as it provides a major source of 'new' nitrogen to the euphotic zone that supports biological carbon export and sequestration. Since most global biogeochemical models include nitrogen fixation only diagnostically, they are not able to capture its spatial pattern sufficiently. Here we present the incorporation of an explicit, dynamic representation of diazotrophic cyanobacteria and the corresponding nitrogen fixation in the global ocean biogeochemical model HAMOCC (Hamburg Ocean Carbon Cycle model), which is part of the Max Planck Institute for Meteorology Earth system model (MPI-ESM). The parameterization of the diazotrophic growth is thereby based on available knowledge about the cyanobacterium Trichodesmium spp., which is considered as the most significant pelagic nitrogen fixer. Evaluation against observations shows that the model successfully reproduces the main spatial distribution of cyanobacteria and nitrogen fixation, covering large parts of the tropical and subtropical oceans. Besides the role of cyanobacteria in marine biogeochemical cycles, their capacity to form extensive surface blooms induces a number of bio-physical feedback mechanisms in the Earth system. The processes driving these interactions, which are related to the alteration of heat absorption, surface albedo and momentum input by wind, are incorporated in the biogeochemical and physical model of the MPI-ESM in order to investigate their impacts on a global scale. First preliminary results will be shown.

  3. Biomass Feedstock National User Facility

    Data.gov (United States)

    Federal Laboratory Consortium — Bioenergy research at the Biomass Feedstock National User Facility (BFNUF) is focused on creating commodity-scale feed-stocks from native biomass that meet the needs...

  4. Importance of incorporating agriculture in conceptual rainfall-runoff models

    Science.gov (United States)

    de Boer-Euser, Tanja; Hrachowitz, Markus; Winsemius, Hessel; Savenije, Hubert

    2016-04-01

    Incorporating spatially variable information is a frequently discussed option to increase the performance of (semi-)distributed conceptual rainfall-runoff models. One of the methods to do this is by using this spatially variable information to delineate Hydrological Response Units (HRUs) within a catchment. In large parts of Europe the original forested land cover is replaced by an agricultural land cover. This change in land cover probably affects the dominant runoff processes in the area, for example by increasing the Hortonian overland flow component, especially on the flatter and higher elevated parts of the catchment. A change in runoff processes implies a change in HRUs as well. A previous version of our model distinguished wetlands (areas close to the stream) from the remainder of the catchment. However, this configuration was not able to reproduce all fast runoff processes, both in summer as in winter. Therefore, this study tests whether the reproduction of fast runoff processes can be improved by incorporating a HRU which explicitly accounts for the effect of agriculture. A case study is carried out in the Ourthe catchment in Belgium. For this case study the relevance of different process conceptualisations is tested stepwise. Among the conceptualisations are Hortonian overland flow in summer and winter, reduced infiltration capacity due to a partly frozen soil and the relative effect of rainfall and snow smelt in case of this frozen soil. The results show that the named processes can make a large difference on event basis, especially the Hortonian overland flow in summer and the combination of rainfall and snow melt on (partly) frozen soil in winter. However, differences diminish when the modelled period of several years is evaluated based on standard metrics like Nash-Sutcliffe Efficiency. These results emphasise on one hand the importance of incorporating the effects of agricultural in conceptual models and on the other hand the importance of more event

  5. Incorporating model parameter uncertainty into inverse treatment planning

    International Nuclear Information System (INIS)

    Lian Jun; Xing Lei

    2004-01-01

    Radiobiological treatment planning depends not only on the accuracy of the models describing the dose-response relation of different tumors and normal tissues but also on the accuracy of tissue specific radiobiological parameters in these models. Whereas the general formalism remains the same, different sets of model parameters lead to different solutions and thus critically determine the final plan. Here we describe an inverse planning formalism with inclusion of model parameter uncertainties. This is made possible by using a statistical analysis-based frameset developed by our group. In this formalism, the uncertainties of model parameters, such as the parameter a that describes tissue-specific effect in the equivalent uniform dose (EUD) model, are expressed by probability density function and are included in the dose optimization process. We found that the final solution strongly depends on distribution functions of the model parameters. Considering that currently available models for computing biological effects of radiation are simplistic, and the clinical data used to derive the models are sparse and of questionable quality, the proposed technique provides us with an effective tool to minimize the effect caused by the uncertainties in a statistical sense. With the incorporation of the uncertainties, the technique has potential for us to maximally utilize the available radiobiology knowledge for better IMRT treatment

  6. Incorporating published univariable associations in diagnostic and prognostic modeling

    Directory of Open Access Journals (Sweden)

    A Debray Thomas P

    2012-08-01

    Full Text Available Abstract Background Diagnostic and prognostic literature is overwhelmed with studies reporting univariable predictor-outcome associations. Currently, methods to incorporate such information in the construction of a prediction model are underdeveloped and unfamiliar to many researchers. Methods This article aims to improve upon an adaptation method originally proposed by Greenland (1987 and Steyerberg (2000 to incorporate previously published univariable associations in the construction of a novel prediction model. The proposed method improves upon the variance estimation component by reconfiguring the adaptation process in established theory and making it more robust. Different variants of the proposed method were tested in a simulation study, where performance was measured by comparing estimated associations with their predefined values according to the Mean Squared Error and coverage of the 90% confidence intervals. Results Results demonstrate that performance of estimated multivariable associations considerably improves for small datasets where external evidence is included. Although the error of estimated associations decreases with increasing amount of individual participant data, it does not disappear completely, even in very large datasets. Conclusions The proposed method to aggregate previously published univariable associations with individual participant data in the construction of a novel prediction models outperforms established approaches and is especially worthwhile when relatively limited individual participant data are available.

  7. Thermodynamic modelling of supercritical water gasification: investigating the effect of biomass composition to aid in the selection of appropriate feedstock material.

    Science.gov (United States)

    Louw, Jeanne; Schwarz, Cara E; Knoetze, Johannes H; Burger, Andries J

    2014-12-01

    A process model developed in Aspen Plus®, was used for the thermodynamic modelling of supercritical water gasification (SCWG) using a wide variety of biomass materials as feedstock. The influence of the composition of the biomass material (in terms of carbon, hydrogen and oxygen content) on various performance indicators (such as gas yields, cold gas efficiency, calorific value of product gas and heat of reaction), were determined at various temperatures (600, 700 and 800°C) and biomass feed concentrations (5, 15 and 25wt.%). Generalised contour plots, based on the biomass composition, were developed for these performance indicators to provide the thermodynamic limits at various operating conditions. These plots can aid in the selection or screening of potential biomass materials and appropriate operating conditions for SCWG prior to conducting experimental work. Copyright © 2014 Elsevier Ltd. All rights reserved.

  8. Invasive plants as feedstock for biochar and bioenergy production.

    Science.gov (United States)

    Liao, Rui; Gao, Bin; Fang, June

    2013-07-01

    In this work, the potential of invasive plant species as feedstock for value-added products (biochar and bioenergy) through pyrolysis was investigated. The product yield rates of two major invasive species in the US, Brazilian Pepper (BP) and Air Potato (AP), were compared to that of two traditional feedstock materials, water oak and energy cane. Three pyrolysis temperatures (300, 450, and 600°C) and four feedstock masses (10, 15, 20, and 25 g) were tested for a total of 12 experimental conditions. AP had high biochar and low oil yields, while BP had a high oil yield. At lower temperatures, the minimum feedstock residence time for biochar and bioenergy production increased at a faster rate as feedstock weight increased than it did at higher temperatures. A simple mathematical model was successfully developed to describe the relationship between feedstock weight and the minimum residence time. Copyright © 2013 Elsevier Ltd. All rights reserved.

  9. A mathematical model for incorporating biofeedback into human postural control

    Directory of Open Access Journals (Sweden)

    Ersal Tulga

    2013-02-01

    Full Text Available Abstract Background Biofeedback of body motion can serve as a balance aid and rehabilitation tool. To date, mathematical models considering the integration of biofeedback into postural control have represented this integration as a sensory addition and limited their application to a single degree-of-freedom representation of the body. This study has two objectives: 1 to develop a scalable method for incorporating biofeedback into postural control that is independent of the model’s degrees of freedom, how it handles sensory integration, and the modeling of its postural controller; and 2 to validate this new model using multidirectional perturbation experimental results. Methods Biofeedback was modeled as an additional torque to the postural controller torque. For validation, this biofeedback modeling approach was applied to a vibrotactile biofeedback device and incorporated into a two-link multibody model with full-state-feedback control that represents the dynamics of bipedal stance. Average response trajectories of body sway and center of pressure (COP to multidirectional surface perturbations of subjects with vestibular deficits were used for model parameterization and validation in multiple perturbation directions and for multiple display resolutions. The quality of fit was quantified using average error and cross-correlation values. Results The mean of the average errors across all tactor configurations and perturbations was 0.24° for body sway and 0.39 cm for COP. The mean of the cross-correlation value was 0.97 for both body sway and COP. Conclusions The biofeedback model developed in this study is capable of capturing experimental response trajectory shapes with low average errors and high cross-correlation values in both the anterior-posterior and medial-lateral directions for all perturbation directions and spatial resolution display configurations considered. The results validate that biofeedback can be modeled as an additional

  10. Incorporating modelled subglacial hydrology into inversions for basal drag

    Science.gov (United States)

    Koziol, Conrad P.; Arnold, Neil

    2017-12-01

    A key challenge in modelling coupled ice-flow-subglacial hydrology is initializing the state and parameters of the system. We address this problem by presenting a workflow for initializing these values at the start of a summer melt season. The workflow depends on running a subglacial hydrology model for the winter season, when the system is not forced by meltwater inputs, and ice velocities can be assumed constant. Key parameters of the winter run of the subglacial hydrology model are determined from an initial inversion for basal drag using a linear sliding law. The state of the subglacial hydrology model at the end of winter is incorporated into an inversion of basal drag using a non-linear sliding law which is a function of water pressure. We demonstrate this procedure in the Russell Glacier area and compare the output of the linear sliding law with two non-linear sliding laws. Additionally, we compare the modelled winter hydrological state to radar observations and find that it is in line with summer rather than winter observations.

  11. Incorporating modelled subglacial hydrology into inversions for basal drag

    Directory of Open Access Journals (Sweden)

    C. P. Koziol

    2017-12-01

    Full Text Available A key challenge in modelling coupled ice-flow–subglacial hydrology is initializing the state and parameters of the system. We address this problem by presenting a workflow for initializing these values at the start of a summer melt season. The workflow depends on running a subglacial hydrology model for the winter season, when the system is not forced by meltwater inputs, and ice velocities can be assumed constant. Key parameters of the winter run of the subglacial hydrology model are determined from an initial inversion for basal drag using a linear sliding law. The state of the subglacial hydrology model at the end of winter is incorporated into an inversion of basal drag using a non-linear sliding law which is a function of water pressure. We demonstrate this procedure in the Russell Glacier area and compare the output of the linear sliding law with two non-linear sliding laws. Additionally, we compare the modelled winter hydrological state to radar observations and find that it is in line with summer rather than winter observations.

  12. Safety models incorporating graph theory based transit indicators.

    Science.gov (United States)

    Quintero, Liliana; Sayed, Tarek; Wahba, Mohamed M

    2013-01-01

    There is a considerable need for tools to enable the evaluation of the safety of transit networks at the planning stage. One interesting approach for the planning of public transportation systems is the study of networks. Network techniques involve the analysis of systems by viewing them as a graph composed of a set of vertices (nodes) and edges (links). Once the transport system is visualized as a graph, various network properties can be evaluated based on the relationships between the network elements. Several indicators can be calculated including connectivity, coverage, directness and complexity, among others. The main objective of this study is to investigate the relationship between network-based transit indicators and safety. The study develops macro-level collision prediction models that explicitly incorporate transit physical and operational elements and transit network indicators as explanatory variables. Several macro-level (zonal) collision prediction models were developed using a generalized linear regression technique, assuming a negative binomial error structure. The models were grouped into four main themes: transit infrastructure, transit network topology, transit route design, and transit performance and operations. The safety models showed that collisions were significantly associated with transit network properties such as: connectivity, coverage, overlapping degree and the Local Index of Transit Availability. As well, the models showed a significant relationship between collisions and some transit physical and operational attributes such as the number of routes, frequency of routes, bus density, length of bus and 3+ priority lanes. Copyright © 2012 Elsevier Ltd. All rights reserved.

  13. An electricity generation planning model incorporating demand response

    International Nuclear Information System (INIS)

    Choi, Dong Gu; Thomas, Valerie M.

    2012-01-01

    Energy policies that aim to reduce carbon emissions and change the mix of electricity generation sources, such as carbon cap-and-trade systems and renewable electricity standards, can affect not only the source of electricity generation, but also the price of electricity and, consequently, demand. We develop an optimization model to determine the lowest cost investment and operation plan for the generating capacity of an electric power system. The model incorporates demand response to price change. In a case study for a U.S. state, we show the price, demand, and generation mix implications of a renewable electricity standard, and of a carbon cap-and-trade policy with and without initial free allocation of carbon allowances. This study shows that both the demand moderating effects and the generation mix changing effects of the policies can be the sources of carbon emissions reductions, and also shows that the share of the sources could differ with different policy designs. The case study provides different results when demand elasticity is excluded, underscoring the importance of incorporating demand response in the evaluation of electricity generation policies. - Highlights: ► We develop an electric power system optimization model including demand elasticity. ► Both renewable electricity and carbon cap-and-trade policies can moderate demand. ► Both policies affect the generation mix, price, and demand for electricity. ► Moderated demand can be a significant source of carbon emission reduction. ► For cap-and-trade policies, initial free allowances change outcomes significantly.

  14. Feedstock recycling of plastics. Selected papers presented at the third International Symposium on Feedstock Recycling of Plastics, Karlsruhe, Sept. 25-29, 2005

    OpenAIRE

    Müller-Hagedorn, Matthias; Bockhorn, Henning [Hrsg.

    2005-01-01

    Feedstock Recycling of Plastics gives a survey of actual fundamental and applied research. It consists of selected contributions that were presented during the Third International Symposium on Feedstock Recycling of Plastics & other Innovative Plastics Recycling Techniques in Karlsruhe (Germany), 2005. The following fundamental issues of feedstock recycling are covered: - Pyrolysis or solvolysis - Pyrolysis: Processes - Strategies - Usages - Modelling - Py...

  15. Bioethanol: fuel or feedstock?

    DEFF Research Database (Denmark)

    Rass-Hansen, Jeppe; Falsig, Hanne; Jørgensen, Betina

    2007-01-01

    Increasing amounts of bioethanol are being produced from fermentation of biomass, mainly to counteract the continuing depletion of fossil resources and the consequential escalation of oil prices. Today, bioethanol is mainly utilized as a fuel or fuel additive in motor vehicles, but it could also...... be used as a versatile feedstock in the chemical industry. Currently the production of carbon-containing commodity chemicals is dependent on fossil resources, and more than 95% of these chemicals are produced from non-renewable carbon resources. The question is: what will be the optimal use of bioethanol...

  16. Tantalum strength model incorporating temperature, strain rate and pressure

    Science.gov (United States)

    Lim, Hojun; Battaile, Corbett; Brown, Justin; Lane, Matt

    Tantalum is a body-centered-cubic (BCC) refractory metal that is widely used in many applications in high temperature, strain rate and pressure environments. In this work, we propose a physically-based strength model for tantalum that incorporates effects of temperature, strain rate and pressure. A constitutive model for single crystal tantalum is developed based on dislocation kink-pair theory, and calibrated to measurements on single crystal specimens. The model is then used to predict deformations of single- and polycrystalline tantalum. In addition, the proposed strength model is implemented into Sandia's ALEGRA solid dynamics code to predict plastic deformations of tantalum in engineering-scale applications at extreme conditions, e.g. Taylor impact tests and Z machine's high pressure ramp compression tests, and the results are compared with available experimental data. Sandia National Laboratories is a multi program laboratory managed and operated by Sandia Corporation, a wholly owned subsidiary of Lockheed Martin Corporation, for the U.S. Department of Energy's National Nuclear Security Administration under contract DE-AC04-94AL85000.

  17. Incorporating Plant Phenology Dynamics in a Biophysical Canopy Model

    Science.gov (United States)

    Barata, Raquel A.; Drewry, Darren

    2012-01-01

    The Multi-Layer Canopy Model (MLCan) is a vegetation model created to capture plant responses to environmental change. Themodel vertically resolves carbon uptake, water vapor and energy exchange at each canopy level by coupling photosynthesis, stomatal conductance and leaf energy balance. The model is forced by incoming shortwave and longwave radiation, as well as near-surface meteorological conditions. The original formulation of MLCan utilized canopy structural traits derived from observations. This project aims to incorporate a plant phenology scheme within MLCan allowing these structural traits to vary dynamically. In the plant phenology scheme implemented here, plant growth is dependent on environmental conditions such as air temperature and soil moisture. The scheme includes functionality that models plant germination, growth, and senescence. These growth stages dictate the variation in six different vegetative carbon pools: storage, leaves, stem, coarse roots, fine roots, and reproductive. The magnitudes of these carbon pools determine land surface parameters such as leaf area index, canopy height, rooting depth and root water uptake capacity. Coupling this phenology scheme with MLCan allows for a more flexible representation of the structure and function of vegetation as it responds to changing environmental conditions.

  18. Incorporation of chemical kinetic models into process control

    International Nuclear Information System (INIS)

    Herget, C.J.; Frazer, J.W.

    1981-01-01

    An important consideration in chemical process control is to determine the precise rationing of reactant streams, particularly when a large time delay exists between the mixing of the reactants and the measurement of the product. In this paper, a method is described for incorporating chemical kinetic models into the control strategy in order to achieve optimum operating conditions. The system is first characterized by determining a reaction rate surface as a function of all input reactant concentrations over a feasible range. A nonlinear constrained optimization program is then used to determine the combination of reactants which produces the specified yield at minimum cost. This operating condition is then used to establish the nominal concentrations of the reactants. The actual operation is determined through a feedback control system employing a Smith predictor. The method is demonstrated on a laboratory bench scale enzyme reactor

  19. Biofuels feedstock development program

    International Nuclear Information System (INIS)

    Wright, L.L.; Cushman, J.H.; Ehrenshaft, A.R.; McLaughlin, S.B.; McNabb, W.A.; Martin, S.A.; Ranney, J.W.; Tuskan, G.A.; Turhollow, A.F.

    1993-11-01

    The Department of Energy's (DOE's) Biofuels Feedstock Development Program (BFDP) leads the nation in the research, development, and demonstration of environmentally acceptable and commercially viable dedicated feedstock supply systems (DFSS). The purpose of this report is to highlight the status and accomplishments of the research that is currently being funded by the BFDP. Highlights summarized here and additional accomplishments are described in more detail in the sections associated with each major program task. A few key accomplishments include (1) development of a methodology for doing a cost-supply analysis for energy crops and the application of that methodology to looking at possible land use changes around a specific energy facility in East Tennessee; (2) preliminary documentation of the relationship between woody crop plantation locations and bird diversity at sites in the Midwest, Canada, and the pacific Northwest supplied indications that woody crop plantations could be beneficial to biodiversity; (3) the initiation of integrated switchgrass variety trials, breeding research, and biotechnology research for the south/southeast region; (4) development of a data base management system for documenting the results of herbaceous energy crop field trials; (5) publication of three issues of Energy Crops Forum and development of a readership of over 2,300 individuals or organizations as determined by positive responses on questionnaires

  20. Modelling of spectroscopic batch process data using grey models to incorporate external information

    NARCIS (Netherlands)

    Gurden, S. P.; Westerhuis, J. A.; Bijlsma, S.; Smilde, A. K.

    2001-01-01

    In both analytical and process chemistry, one common aim is to build models describing measured data. In cases where additional information about the chemical system is available, this can be incorporated into the model with the aim of improving model fit and interpretability. A model which consists

  1. Incorporating a 360 Degree Evaluation Model IOT Transform the USMC Performance Evaluation System

    Science.gov (United States)

    2005-02-08

    Incorporating a 360 Evaluation Model IOT Transform the USMC Performance Evaluation System EWS 2005 Subject Area Manpower...Incorporating a 360 Evaluation Model IOT Transform the USMC Performance Evaluation System” Contemporary...COVERED 00-00-2005 to 00-00-2005 4. TITLE AND SUBTITLE Incorporating a 360 Evaluation Model IOT Transform the USMC Performance

  2. Digital terrain model generalization incorporating scale, semantic and cognitive constraints

    Science.gov (United States)

    Partsinevelos, Panagiotis; Papadogiorgaki, Maria

    2014-05-01

    Cartographic generalization is a well-known process accommodating spatial data compression, visualization and comprehension under various scales. In the last few years, there are several international attempts to construct tangible GIS systems, forming real 3D surfaces using a vast number of mechanical parts along a matrix formation (i.e., bars, pistons, vacuums). Usually, moving bars upon a structured grid push a stretching membrane resulting in a smooth visualization for a given surface. Most of these attempts suffer either in their cost, accuracy, resolution and/or speed. Under this perspective, the present study proposes a surface generalization process that incorporates intrinsic constrains of tangible GIS systems including robotic-motor movement and surface stretching limitations. The main objective is to provide optimized visualizations of 3D digital terrain models with minimum loss of information. That is, to minimize the number of pixels in a raster dataset used to define a DTM, while reserving the surface information. This neighborhood type of pixel relations adheres to the basics of Self Organizing Map (SOM) artificial neural networks, which are often used for information abstraction since they are indicative of intrinsic statistical features contained in the input patterns and provide concise and characteristic representations. Nevertheless, SOM remains more like a black box procedure not capable to cope with possible particularities and semantics of the application at hand. E.g. for coastal monitoring applications, the near - coast areas, surrounding mountains and lakes are more important than other features and generalization should be "biased"-stratified to fulfill this requirement. Moreover, according to the application objectives, we extend the SOM algorithm to incorporate special types of information generalization by differentiating the underlying strategy based on topologic information of the objects included in the application. The final

  3. The California Biomass Crop Adoption Model estimates biofuel feedstock crop production across diverse agro-ecological zones within the state, under different future climates

    Science.gov (United States)

    Kaffka, S.; Jenner, M.; Bucaram, S.; George, N.

    2012-12-01

    Both regulators and businesses need realistic estimates for the potential production of biomass feedstocks for biofuels and bioproducts. This includes the need to understand how climate change will affect mid-tem and longer-term crop performance and relative advantage. The California Biomass Crop Adoption Model is a partial mathematical programming optimization model that estimates the profit level needed for new crop adoption, and the crop(s) displaced when a biomass feedstock crop is added to the state's diverse set of cropping systems, in diverse regions of the state. Both yield and crop price, as elements of profit, can be varied. Crop adoption is tested against current farmer preferences derived from analysis of 10 years crop production data for all crops produced in California, collected by the California Department of Pesticide Regulation. Analysis of this extensive data set resulted in 45 distinctive, representative farming systems distributed across the state's diverse agro-ecological regions. Estimated yields and water use are derived from field trials combined with crop simulation, reported elsewhere. Crop simulation is carried out under different weather and climate assumptions. Besides crop adoption and displacement, crop resource use is also accounted, derived from partial budgets used for each crop's cost of production. Systematically increasing biofuel crop price identified areas of the state where different types of crops were most likely to be adopted. Oilseed crops like canola that can be used for biodiesel production had the greatest potential to be grown in the Sacramento Valley and other northern regions, while sugar beets (for ethanol) had the greatest potential in the northern San Joaquin Valley region, and sweet sorghum in the southern San Joaquin Valley. Up to approximately 10% of existing annual cropland in California was available for new crop adoption. New crops are adopted if the entire cropping system becomes more profitable. In

  4. Alternative Feedstocks Program Technical and Economic Assessment: Thermal/Chemical and Bioprocessing Components

    Energy Technology Data Exchange (ETDEWEB)

    Bozell, J. J.; Landucci, R.

    1993-07-01

    This resource document on biomass to chemicals opportunities describes the development of a technical and market rationale for incorporating renewable feedstocks into the chemical industry in both a qualitative and quantitative sense. The term "renewable feedstock?s" can be defined to include a huge number of materials such as agricultural crops rich in starch, lignocellulosic materials (biomass), or biomass material recovered from a variety of processing wastes.

  5. Preprocessing Moist Lignocellulosic Biomass for Biorefinery Feedstocks

    Energy Technology Data Exchange (ETDEWEB)

    Neal Yancey; Christopher T. Wright; Craig Conner; J. Richard Hess

    2009-06-01

    Biomass preprocessing is one of the primary operations in the feedstock assembly system of a lignocellulosic biorefinery. Preprocessing is generally accomplished using industrial grinders to format biomass materials into a suitable biorefinery feedstock for conversion to ethanol and other bioproducts. Many factors affect machine efficiency and the physical characteristics of preprocessed biomass. For example, moisture content of the biomass as received from the point of production has a significant impact on overall system efficiency and can significantly affect the characteristics (particle size distribution, flowability, storability, etc.) of the size-reduced biomass. Many different grinder configurations are available on the market, each with advantages under specific conditions. Ultimately, the capacity and/or efficiency of the grinding process can be enhanced by selecting the grinder configuration that optimizes grinder performance based on moisture content and screen size. This paper discusses the relationships of biomass moisture with respect to preprocessing system performance and product physical characteristics and compares data obtained on corn stover, switchgrass, and wheat straw as model feedstocks during Vermeer HG 200 grinder testing. During the tests, grinder screen configuration and biomass moisture content were varied and tested to provide a better understanding of their relative impact on machine performance and the resulting feedstock physical characteristics and uniformity relative to each crop tested.

  6. Incorporation of ice sheet models into an Earth system model: Focus ...

    Indian Academy of Sciences (India)

    Oleg Rybak

    2018-03-06

    Mar 6, 2018 ... Elaboration of a modern Earth system model (ESM) requires incorporation of ice sheet dynamics. Coupling of an ice sheet model (ICM) to an AOGCM is complicated by essential differences in spatial and temporal scales of cryospheric, atmospheric and oceanic components. To overcome this difficulty, we ...

  7. CARBONIZER TESTS WITH LAKELAND FEEDSTOCKS

    Energy Technology Data Exchange (ETDEWEB)

    C. Lu; Z. Fan; R. Froehlich; A. Robertson

    2003-09-01

    Research has been conducted under United States Department of Energy Contract (USDOE) DE-AC21-86MC21023 to develop a new type of coal-fired plant for electric power generation. This new type of plant, called a Second Generation Pressurized Fluidized Bed Combustion Plant (2nd Gen PFB), offers the promise of efficiencies greater than 48%, with both emissions and a cost of electricity that are significantly lower than those of conventional pulverized coal-fired (PC) plants with wet flue gas desulfurization/scrubbers. The 2nd Gen PFB plant incorporates the partial gasification of coal in a carbonizer, the combustion of carbonizer char in a pressurized circulating fluidized (PCFB) bed boiler, and the combustion of carbonizer syngas in a topping combustor to achieve gas turbine inlet temperatures of 2700 F and higher. Under the USDOE Clean Coal V Demonstration Plant Program, a nominal 260 MWe plant demonstrating 2nd Gen PFB technology has been proposed for construction at the McIntosh Power Plant of the City of Lakeland, Florida. In the September-December 1997 time period, four test runs were conducted in Foster Wheeler's 12-inch diameter carbonizer pilot plant in Livingston New Jersey to ascertain carbonizer performance characteristics with the Kentucky No. 9 coal and Florida limestone proposed for use in the Lakeland plant. The tests were of a short-term nature exploring carbonizer carbon conversions, sulfur capture efficiencies and syngas alkali levels. The tests were successful; observed carbonizer performance was in agreement with predictions and no operating problems, attributed to the planned feedstocks, were encountered. The results of the four test runs are reported herein.

  8. ASSERT FY16 Analysis of Feedstock Companion Markets

    International Nuclear Information System (INIS)

    Lamers, Patrick; Hansen, Jason; Jacobson, Jacob J.; Nguyen, Thuy; Nair, Shyam; Searcy, Erin; Hess, J. Richard

    2016-01-01

    Meeting Co-Optima biofuel production targets will require large quantities of mobilized biomass feedstock. Mobilization is of key importance as there is an abundance of biomass resources, yet little is available for purchase, let alone at desired quantity and quality levels needed for a continuous operation, e.g., a biorefinery. Therefore Co-Optima research includes outlining a path towards feedstock production at scale by understanding routes to mobilizing large quantities of biomass feedstock. Continuing along the vertically-integrated path that pioneer cellulosic biorefineries have taken will constrain the bioenergy industry to high biomass yield areas, limiting its ability to reach biofuel production at scale. To advance the cellulosic biofuels industry, a separation between feedstock supply and conversion is necessary. Thus, in contrast to the vertically integrated supply chain, two industries are required: a feedstock industry and a conversion industry. The split is beneficial for growers and feedstock processers as they are able to sell into multiple markets. That is, depots that produce value-add feedstock intermediates that are fully fungible in both the biofuels refining and other, so-called companion markets. As the biofuel industry is currently too small to leverage significant investment in up-stream infrastructure build-up, it requires an established (companion) market to secure demand, which de-risks potential investments and makes a build-up of processing and other logistics infrastructure more likely. A common concern to this theory however is that more demand by other markets could present a disadvantage for biofuels production as resource competition may increase prices leading to reduced availability of low-cost feedstock for biorefineries. To analyze the dynamics across multiple markets vying for the same resources, particularly the potential effects on resource price and distribution, the Companion Market Model (CMM) has been developed in this

  9. ASSERT FY16 Analysis of Feedstock Companion Markets

    Energy Technology Data Exchange (ETDEWEB)

    Lamers, Patrick [Idaho National Lab. (INL), Idaho Falls, ID (United States); Hansen, Jason [Idaho National Lab. (INL), Idaho Falls, ID (United States); Jacobson, Jacob J. [Idaho National Lab. (INL), Idaho Falls, ID (United States); Nguyen, Thuy [Idaho National Lab. (INL), Idaho Falls, ID (United States); Nair, Shyam [Idaho National Lab. (INL), Idaho Falls, ID (United States); Searcy, Erin [Idaho National Lab. (INL), Idaho Falls, ID (United States); Hess, J. Richard [Idaho National Lab. (INL), Idaho Falls, ID (United States)

    2016-09-01

    Meeting Co-Optima biofuel production targets will require large quantities of mobilized biomass feedstock. Mobilization is of key importance as there is an abundance of biomass resources, yet little is available for purchase, let alone at desired quantity and quality levels needed for a continuous operation, e.g., a biorefinery. Therefore Co-Optima research includes outlining a path towards feedstock production at scale by understanding routes to mobilizing large quantities of biomass feedstock. Continuing along the vertically-integrated path that pioneer cellulosic biorefineries have taken will constrain the bioenergy industry to high biomass yield areas, limiting its ability to reach biofuel production at scale. To advance the cellulosic biofuels industry, a separation between feedstock supply and conversion is necessary. Thus, in contrast to the vertically integrated supply chain, two industries are required: a feedstock industry and a conversion industry. The split is beneficial for growers and feedstock processers as they are able to sell into multiple markets. That is, depots that produce value-add feedstock intermediates that are fully fungible in both the biofuels refining and other, so-called companion markets. As the biofuel industry is currently too small to leverage significant investment in up-stream infrastructure build-up, it requires an established (companion) market to secure demand, which de-risks potential investments and makes a build-up of processing and other logistics infrastructure more likely. A common concern to this theory however is that more demand by other markets could present a disadvantage for biofuels production as resource competition may increase prices leading to reduced availability of low-cost feedstock for biorefineries. To analyze the dynamics across multiple markets vying for the same resources, particularly the potential effects on resource price and distribution, the Companion Market Model (CMM) has been developed in this

  10. Implementing the Standards: Incorporating Mathematical Modeling into the Curriculum.

    Science.gov (United States)

    Swetz, Frank

    1991-01-01

    Following a brief historical review of the mechanism of mathematical modeling, examples are included that associate a mathematical model with given data (changes in sea level) and that model a real-life situation (process of parallel parking). Also provided is the rationale for the curricular implementation of mathematical modeling. (JJK)

  11. Incorporating inductances in tissue-scale models of cardiac electrophysiology

    Science.gov (United States)

    Rossi, Simone; Griffith, Boyce E.

    2017-09-01

    In standard models of cardiac electrophysiology, including the bidomain and monodomain models, local perturbations can propagate at infinite speed. We address this unrealistic property by developing a hyperbolic bidomain model that is based on a generalization of Ohm's law with a Cattaneo-type model for the fluxes. Further, we obtain a hyperbolic monodomain model in the case that the intracellular and extracellular conductivity tensors have the same anisotropy ratio. In one spatial dimension, the hyperbolic monodomain model is equivalent to a cable model that includes axial inductances, and the relaxation times of the Cattaneo fluxes are strictly related to these inductances. A purely linear analysis shows that the inductances are negligible, but models of cardiac electrophysiology are highly nonlinear, and linear predictions may not capture the fully nonlinear dynamics. In fact, contrary to the linear analysis, we show that for simple nonlinear ionic models, an increase in conduction velocity is obtained for small and moderate values of the relaxation time. A similar behavior is also demonstrated with biophysically detailed ionic models. Using the Fenton-Karma model along with a low-order finite element spatial discretization, we numerically analyze differences between the standard monodomain model and the hyperbolic monodomain model. In a simple benchmark test, we show that the propagation of the action potential is strongly influenced by the alignment of the fibers with respect to the mesh in both the parabolic and hyperbolic models when using relatively coarse spatial discretizations. Accurate predictions of the conduction velocity require computational mesh spacings on the order of a single cardiac cell. We also compare the two formulations in the case of spiral break up and atrial fibrillation in an anatomically detailed model of the left atrium, and we examine the effect of intracellular and extracellular inductances on the virtual electrode phenomenon.

  12. Biomass Feedstock and Conversion Supply System Design and Analysis

    Energy Technology Data Exchange (ETDEWEB)

    Jacobson, Jacob J. [Idaho National Lab. (INL), Idaho Falls, ID (United States); Roni, Mohammad S. [Idaho National Lab. (INL), Idaho Falls, ID (United States); Lamers, Patrick [Idaho National Lab. (INL), Idaho Falls, ID (United States); Cafferty, Kara G. [Idaho National Lab. (INL), Idaho Falls, ID (United States)

    2014-09-01

    Idaho National Laboratory (INL) supports the U.S. Department of Energy’s bioenergy research program. As part of the research program INL investigates the feedstock logistics economics and sustainability of these fuels. A series of reports were published between 2000 and 2013 to demonstrate the feedstock logistics cost. Those reports were tailored to specific feedstock and conversion process. Although those reports are different in terms of conversion, some of the process in the feedstock logistic are same for each conversion process. As a result, each report has similar information. A single report can be designed that could bring all commonality occurred in the feedstock logistics process while discussing the feedstock logistics cost for different conversion process. Therefore, this report is designed in such a way that it can capture different feedstock logistics cost while eliminating the need of writing a conversion specific design report. Previous work established the current costs based on conventional equipment and processes. The 2012 programmatic target was to demonstrate a delivered biomass logistics cost of $55/dry ton for woody biomass delivered to fast pyrolysis conversion facility. The goal was achieved by applying field and process demonstration unit-scale data from harvest, collection, storage, preprocessing, handling, and transportation operations into INL’s biomass logistics model. The goal of the 2017 Design Case is to enable expansion of biofuels production beyond highly productive resource areas by breaking the reliance of cost-competitive biofuel production on a single, low-cost feedstock. The 2017 programmatic target is to supply feedstock to the conversion facility that meets the in-feed conversion process quality specifications at a total logistics cost of $80/dry T. The $80/dry T. target encompasses total delivered feedstock cost, including both grower payment and logistics costs, while meeting all conversion in-feed quality targets

  13. Innovative technological paradigm-based approach towards biofuel feedstock

    International Nuclear Information System (INIS)

    Xu, Jiuping; Li, Meihui

    2017-01-01

    Highlights: • DAS was developed through an innovative approach towards literature mining and technological paradigm theory. • A novel concept of biofuel feedstock development paradigm (BFDP) is proposed. • The biofuel production diffusion velocity model gives predictions for the future. • Soft path appears to be the driving force for the new paradigm shift. • An integrated biofuel production feedstock system is expected to play a significant role in a low-carbon sustainable future. - Abstract: Biofuels produced from renewable energy biomass are playing a more significant role because of the environmental problems resulting from the use of fossil fuels. However, a major problem with biofuel production is that despite the range of feedstock that can be used, raw material availability varies considerably. By combining a series of theories and methods, the research objective of this study is to determine the current developments and the future trends in biofuel feedstock. By combining technological paradigm theory with literature mining, it was found that biofuel feedstock production development followed a three-stage trajectory, which was in accordance with the traditional technological paradigm – the S-curve. This new curve can be divided into BFDP (biofuel feedstock development paradigm) competition, BFDP diffusion, and BFDP shift. The biofuel production diffusion velocity model showed that there has been constant growth from 2000, with the growth rate reaching a peak in 2008, after which time it began to drop. Biofuel production worldwide is expected to remain unchanged until 2030 when a paradigm shift is expected. This study also illustrates the results of our innovative procedure – a combination of the data analysis system and the technological paradigm theory – for the present biofuel feedstock soft path that will lead to this paradigm shift, with integrated biofuel production feedstock systems expected to be a significant new trend.

  14. Feedstock characterization and recommended procedures

    International Nuclear Information System (INIS)

    Chum, H.L.; Milne, T.A.; Johnson, D.K.; Agblevor, F.A.

    1993-01-01

    Using biomass for non-conventional applications such as feedstocks for fuels, chemicals, new materials, and electric power production requires knowledge of biomass characteristics important to these processes, and characterization techniques that are more appropriate than those employed today for conventional applications of food, feed, and fiber. This paper reviews feedstock characterization and standardization methodologies, and identifies research and development needs. It reviews the international cooperation involved in determining biomass characteristics and standards that has culminated in preparing four biomass samples currently available from the National Institute of Standards and Technology (NIST)

  15. A quantum model of exaptation: incorporating potentiality into evolutionary theory.

    Science.gov (United States)

    Gabora, Liane; Scott, Eric O; Kauffman, Stuart

    2013-09-01

    The phenomenon of preadaptation, or exaptation (wherein a trait that originally evolved to solve one problem is co-opted to solve a new problem) presents a formidable challenge to efforts to describe biological phenomena using a classical (Kolmogorovian) mathematical framework. We develop a quantum framework for exaptation with examples from both biological and cultural evolution. The state of a trait is written as a linear superposition of a set of basis states, or possible forms the trait could evolve into, in a complex Hilbert space. These basis states are represented by mutually orthogonal unit vectors, each weighted by an amplitude term. The choice of possible forms (basis states) depends on the adaptive function of interest (e.g., ability to metabolize lactose or thermoregulate), which plays the role of the observable. Observables are represented by self-adjoint operators on the Hilbert space. The possible forms (basis states) corresponding to this adaptive function (observable) are called eigenstates. The framework incorporates key features of exaptation: potentiality, contextuality, nonseparability, and emergence of new features. However, since it requires that one enumerate all possible contexts, its predictive value is limited, consistent with the assertion that there exists no biological equivalent to "laws of motion" by which we can predict the evolution of the biosphere. Copyright © 2013 Elsevier Ltd. All rights reserved.

  16. Incorporating Contagion in Portfolio Credit Risk Models Using Network Theory

    NARCIS (Netherlands)

    Anagnostou, I.; Sourabh, S.; Kandhai, D.

    2018-01-01

    Portfolio credit risk models estimate the range of potential losses due to defaults or deteriorations in credit quality. Most of these models perceive default correlation as fully captured by the dependence on a set of common underlying risk factors. In light of empirical evidence, the ability of

  17. Incorporating measurement error in n = 1 psychological autoregressive modeling

    Science.gov (United States)

    Schuurman, Noémi K.; Houtveen, Jan H.; Hamaker, Ellen L.

    2015-01-01

    Measurement error is omnipresent in psychological data. However, the vast majority of applications of autoregressive time series analyses in psychology do not take measurement error into account. Disregarding measurement error when it is present in the data results in a bias of the autoregressive parameters. We discuss two models that take measurement error into account: An autoregressive model with a white noise term (AR+WN), and an autoregressive moving average (ARMA) model. In a simulation study we compare the parameter recovery performance of these models, and compare this performance for both a Bayesian and frequentist approach. We find that overall, the AR+WN model performs better. Furthermore, we find that for realistic (i.e., small) sample sizes, psychological research would benefit from a Bayesian approach in fitting these models. Finally, we illustrate the effect of disregarding measurement error in an AR(1) model by means of an empirical application on mood data in women. We find that, depending on the person, approximately 30–50% of the total variance was due to measurement error, and that disregarding this measurement error results in a substantial underestimation of the autoregressive parameters. PMID:26283988

  18. Improving hydrological simulations by incorporating GRACE data for model calibration

    Science.gov (United States)

    Bai, Peng; Liu, Xiaomang; Liu, Changming

    2018-02-01

    Hydrological model parameters are typically calibrated by observed streamflow data. This calibration strategy is questioned when the simulated hydrological variables of interest are not limited to streamflow. Well-performed streamflow simulations do not guarantee the reliable reproduction of other hydrological variables. One of the reasons is that hydrological model parameters are not reasonably identified. The Gravity Recovery and Climate Experiment (GRACE)-derived total water storage change (TWSC) data provide an opportunity to constrain hydrological model parameterizations in combination with streamflow observations. In this study, a multi-objective calibration scheme based on GRACE-derived TWSC and streamflow observations was compared with the traditional single-objective calibration scheme based on only streamflow simulations. Two hydrological models were employed on 22 catchments in China with different climatic conditions. The model evaluations were performed using observed streamflows, GRACE-derived TWSC, and actual evapotranspiration (ET) estimates from flux towers and from the water balance approach. Results showed that the multi-objective calibration scheme provided more reliable TWSC and ET simulations without significant deterioration in the accuracy of streamflow simulations than the single-objective calibration. The improvement in TWSC and ET simulations was more significant in relatively dry catchments than in relatively wet catchments. In addition, hydrological models calibrated using GRACE-derived TWSC data alone cannot obtain accurate runoff simulations in ungauged catchments. This study highlights the importance of including additional constraints in addition to streamflow observations to improve performances of hydrological models.

  19. Design of a GIS-Based Web Application for Simulating Biofuel Feedstock Yields

    Directory of Open Access Journals (Sweden)

    Olga Prilepova

    2014-07-01

    Full Text Available Short rotation woody crops (SRWC, such as hybrid poplar, have the potential to serve as a valuable feedstock for cellulosic biofuels. Spatial estimates of biomass yields under different management regimes are required for assisting stakeholders in making better management decisions and to establish viable woody cropping systems for biofuel production. To support stakeholders in their management decisions, we have developed a GIS-based web interface using a modified 3PG model for spatially predicting poplar biomass yields under different management and climate conditions in the U.S. Pacific Northwest region. The application is implemented with standard HTML5 components, allowing its use in a modern browser and dynamically adjusting to the client screen size and device. In addition, cloud storage of the results makes them accessible on any Internet-enabled device. The web interface appears simple, but is powerful in parameter manipulation and in visualizing and sharing the results. Overall, this application comprises dynamic features that enable users to run SRWC crop growth simulations based on GIS information and contributes significantly to choosing appropriate feedstock growing locations, anticipating the desired physiological properties of the feedstock and incorporating the management and policy analysis needed for growing hybrid poplar plantations.

  20. Markov modulated Poisson process models incorporating covariates for rainfall intensity.

    Science.gov (United States)

    Thayakaran, R; Ramesh, N I

    2013-01-01

    Time series of rainfall bucket tip times at the Beaufort Park station, Bracknell, in the UK are modelled by a class of Markov modulated Poisson processes (MMPP) which may be thought of as a generalization of the Poisson process. Our main focus in this paper is to investigate the effects of including covariate information into the MMPP model framework on statistical properties. In particular, we look at three types of time-varying covariates namely temperature, sea level pressure, and relative humidity that are thought to be affecting the rainfall arrival process. Maximum likelihood estimation is used to obtain the parameter estimates, and likelihood ratio tests are employed in model comparison. Simulated data from the fitted model are used to make statistical inferences about the accumulated rainfall in the discrete time interval. Variability of the daily Poisson arrival rates is studied.

  1. Incorporating spiritual beliefs into a cognitive model of worry.

    Science.gov (United States)

    Rosmarin, David H; Pirutinsky, Steven; Auerbach, Randy P; Björgvinsson, Thröstur; Bigda-Peyton, Joseph; Andersson, Gerhard; Pargament, Kenneth I; Krumrei, Elizabeth J

    2011-07-01

    Cognitive theory and research have traditionally highlighted the relevance of the core beliefs about oneself, the world, and the future to human emotions. For some individuals, however, core beliefs may also explicitly involve spiritual themes. In this article, we propose a cognitive model of worry, in which positive/negative beliefs about the Divine affect symptoms through the mechanism of intolerance of uncertainty. Using mediation analyses, we found support for our model across two studies, in particular, with regards to negative spiritual beliefs. These findings highlight the importance of assessing for spiritual alongside secular convictions when creating cognitive-behavioral case formulations in the treatment of religious individuals. © 2011 Wiley Periodicals, Inc.

  2. 2009 Feedstocks Platform Review Report

    Energy Technology Data Exchange (ETDEWEB)

    Ferrell, John [Office of Energy Efficiency and Renewable Energy (EERE), Washington, DC (United States)

    2009-12-01

    This document summarizes the recommendations and evaluations provided by an independent external panel of experts at the U.S. Department of Energy Biomass Program‘s Feedstock platform review meeting, held on April 8–10, 2009, at the Grand Hyatt Washington, Washington, D.C.

  3. 75 FR 56487 - Airworthiness Directives; Erickson Air-Crane Incorporated Model S-64F Helicopters

    Science.gov (United States)

    2010-09-16

    ... Federal Aviation Administration 14 CFR Part 39 RIN 2120-AA64 Airworthiness Directives; Erickson Air-Crane... Air-Crane Incorporated (Erickson Air-Crane) Model S- 64F helicopters. The AD would require, at... the service information identified in this proposed AD from Erickson Air-Crane Incorporated, 3100...

  4. Making Invasion models useful for decision makers; incorporating uncertainty, knowledge gaps, and decision-making preferences

    Science.gov (United States)

    Denys Yemshanov; Frank H Koch; Mark Ducey

    2015-01-01

    Uncertainty is inherent in model-based forecasts of ecological invasions. In this chapter, we explore how the perceptions of that uncertainty can be incorporated into the pest risk assessment process. Uncertainty changes a decision maker’s perceptions of risk; therefore, the direct incorporation of uncertainty may provide a more appropriate depiction of risk. Our...

  5. 75 FR 20265 - Airworthiness Directives; Liberty Aerospace Incorporated Model XL-2 Airplanes

    Science.gov (United States)

    2010-04-19

    ...-020-AD; Amendment 39-16264; AD 2009-08-05 R1] RIN 2120-AA64 Airworthiness Directives; Liberty... Liberty Aerospace Incorporated Model XL-2 airplanes. AD 2009-08-05 currently requires repetitively... approved the incorporation by reference of Liberty Aerospace, Inc. Service Document Critical Service...

  6. Day-to-day route choice modeling incorporating inertial behavior

    NARCIS (Netherlands)

    van Essen, Mariska Alice; Rakha, H.; Vreeswijk, Jacob Dirk; Wismans, Luc Johannes Josephus; van Berkum, Eric C.

    2015-01-01

    Accurate route choice modeling is one of the most important aspects when predicting the effects of transport policy and dynamic traffic management. Moreover, the effectiveness of intervention measures to a large extent depends on travelers’ response to the changes these measures cause. As a

  7. Modelling toluene oxidation : Incorporation of mass transfer phenomena

    NARCIS (Netherlands)

    Hoorn, J.A.A.; van Soolingen, J.; Versteeg, G. F.

    The kinetics of the oxidation of toluene have been studied in close interaction with the gas-liquid mass transfer occurring in the reactor. Kinetic parameters for a simple model have been estimated on basis of experimental observations performed under industrial conditions. The conclusions for the

  8. Do Knowledge-Component Models Need to Incorporate Representational Competencies?

    Science.gov (United States)

    Rau, Martina Angela

    2017-01-01

    Traditional knowledge-component models describe students' content knowledge (e.g., their ability to carry out problem-solving procedures or their ability to reason about a concept). In many STEM domains, instruction uses multiple visual representations such as graphs, figures, and diagrams. The use of visual representations implies a…

  9. Incorporation of ice sheet models into an Earth system model: Focus on methodology of coupling

    Science.gov (United States)

    Rybak, Oleg; Volodin, Evgeny; Morozova, Polina; Nevecherja, Artiom

    2018-03-01

    Elaboration of a modern Earth system model (ESM) requires incorporation of ice sheet dynamics. Coupling of an ice sheet model (ICM) to an AOGCM is complicated by essential differences in spatial and temporal scales of cryospheric, atmospheric and oceanic components. To overcome this difficulty, we apply two different approaches for the incorporation of ice sheets into an ESM. Coupling of the Antarctic ice sheet model (AISM) to the AOGCM is accomplished via using procedures of resampling, interpolation and assigning to the AISM grid points annually averaged meanings of air surface temperature and precipitation fields generated by the AOGCM. Surface melting, which takes place mainly on the margins of the Antarctic peninsula and on ice shelves fringing the continent, is currently ignored. AISM returns anomalies of surface topography back to the AOGCM. To couple the Greenland ice sheet model (GrISM) to the AOGCM, we use a simple buffer energy- and water-balance model (EWBM-G) to account for orographically-driven precipitation and other sub-grid AOGCM-generated quantities. The output of the EWBM-G consists of surface mass balance and air surface temperature to force the GrISM, and freshwater run-off to force thermohaline circulation in the oceanic block of the AOGCM. Because of a rather complex coupling procedure of GrIS compared to AIS, the paper mostly focuses on Greenland.

  10. Constitutive modeling of coronary artery bypass graft with incorporated torsion

    Czech Academy of Sciences Publication Activity Database

    Horný, L.; Chlup, Hynek; Žitný, R.; Adámek, T.

    2009-01-01

    Roč. 49, č. 2 (2009), s. 273-277 ISSN 0543-5846 R&D Projects: GA ČR(CZ) GA106/08/0557 Institutional research plan: CEZ:AV0Z20760514 Keywords : coronary artery bypass graft * constitutive model * digital image correlation Subject RIV: BJ - Thermodynamics Impact factor: 0.439, year: 2009 http://web.tuke.sk/sjf-kamam/mmams2009/contents.pdf

  11. Survey of alternative feedstocks for biodiesel production

    Science.gov (United States)

    Summarized will be results obtained from the production of biodiesel from several alternative feedstocks with promising agronomic characteristics. Such feedstocks include camelina (Camelina sativa L.), coriander (Coriandrum sativum L.), field pennycress (Thlaspi arvense L.), and meadowfoam (Limnanth...

  12. Incorporating affective bias in models of human decision making

    Science.gov (United States)

    Nygren, Thomas E.

    1991-01-01

    Research on human decision making has traditionally focused on how people actually make decisions, how good their decisions are, and how their decisions can be improved. Recent research suggests that this model is inadequate. Affective as well as cognitive components drive the way information about relevant outcomes and events is perceived, integrated, and used in the decision making process. The affective components include how the individual frames outcomes as good or bad, whether the individual anticipates regret in a decision situation, the affective mood state of the individual, and the psychological stress level anticipated or experienced in the decision situation. A focus of the current work has been to propose empirical studies that will attempt to examine in more detail the relationships between the latter two critical affective influences (mood state and stress) on decision making behavior.

  13. Incorporating Probability Models of Complex Test Structures to Perform Technology Independent FPGA Single Event Upset Analysis

    Science.gov (United States)

    Berg, M. D.; Kim, H. S.; Friendlich, M. A.; Perez, C. E.; Seidlick, C. M.; LaBel, K. A.

    2011-01-01

    We present SEU test and analysis of the Microsemi ProASIC3 FPGA. SEU Probability models are incorporated for device evaluation. Included is a comparison to the RTAXS FPGA illustrating the effectiveness of the overall testing methodology.

  14. INCORPORATION OF MECHANISTIC INFORMATION IN THE ARSENIC PBPK MODEL DEVELOPMENT PROCESS

    Science.gov (United States)

    INCORPORATING MECHANISTIC INSIGHTS IN A PBPK MODEL FOR ARSENICElaina M. Kenyon, Michael F. Hughes, Marina V. Evans, David J. Thomas, U.S. EPA; Miroslav Styblo, University of North Carolina; Michael Easterling, Analytical Sciences, Inc.A physiologically based phar...

  15. Generating a geospatial database of U.S. regional feedstock production for use in evaluating the environmental footprint of biofuels.

    Science.gov (United States)

    Holder, Christopher T; Cleland, Joshua C; LeDuc, Stephen D; Andereck, Zac; Hogan, Chris; Martin, Kristen M

    2016-04-01

    The potential environmental effects of increased U.S. biofuel production often vary depending upon the location and type of land used to produce biofuel feedstocks. However, complete, annual data are generally lacking regarding feedstock production by specific location. Corn is the dominant biofuel feedstock in the U.S., so here we present methods for estimating where bioethanol corn feedstock is grown annually and how much is used by U.S. ethanol biorefineries. We use geospatial software and publicly available data to map locations of biorefineries, estimate their corn feedstock requirements, and estimate the feedstock production locations and quantities. We combined these data and estimates into a Bioethanol Feedstock Geospatial Database (BFGD) for years 2005-2010. We evaluated the performance of the methods by assessing how well the feedstock geospatial model matched our estimates of locally-sourced feedstock demand. On average, the model met approximately 89 percent of the total estimated local feedstock demand across the studied years-within approximately 25-to-40 kilometers of the biorefinery in the majority of cases. We anticipate that these methods could be used for other years and feedstocks, and can be subsequently applied to estimate the environmental footprint of feedstock production. Methods used to develop the Bioethanol Feedstock Geospatial Database (BFGD) provide a means of estimating the amount and location of U.S. corn harvested for use as U.S. bioethanol feedstock. Such estimates of geospatial feedstock production may be used to evaluate environmental impacts of bioethanol production and to identify conservation priorities. The BFGD is available for 2005-2010, and the methods may be applied to additional years, locations, and potentially other biofuels and feedstocks.

  16. Process for desulfurizing petroleum feedstocks

    Science.gov (United States)

    Gordon, John Howard; Alvare, Javier

    2014-06-10

    A process for upgrading an oil feedstock includes reacting the oil feedstock with a quantity of an alkali metal, wherein the reaction produces solid materials and liquid materials. The solid materials are separated from the liquid materials. The solid materials may be washed and heat treated by heating the materials to a temperature above 400.degree. C. The heat treating occurs in an atmosphere that has low oxygen and water content. Once heat treated, the solid materials are added to a solution comprising a polar solvent, where sulfide, hydrogen sulfide or polysulfide anions dissolve. The solution comprising polar solvent is then added to an electrolytic cell, which during operation, produces alkali metal and sulfur.

  17. Proceedings. Feedstock preparation and quality 1997 workshop

    Energy Technology Data Exchange (ETDEWEB)

    Mattsson, Jan Erik [ed.

    1998-06-01

    The IEA Bioenergy Feedstock Preparation and Quality 1997 Workshop dealt with fuel feedstock quality improvement and methods to determine feedstock properties. It was arranged by the Swedish Univ. of Agricultural Sciences on behalf of the IEA Bioenergy Task XII Activity 4.1 Feedstock Preparation and Quality. This Activity is a 3-year cooperation 1995-1997 between Denmark, Sweden and the USA, mainly based on information exchange. The workshop had two sections: presentations by invited experts, and country reports on recent development in feedstock preparation and quality in the three participating countries. Separate abstracts have been prepared for four of the six papers presented

  18. Synthesis of fuels and feedstocks

    Energy Technology Data Exchange (ETDEWEB)

    Sutton, Andrew D.; Brooks, Ty; Jenkins, Rhodri; Moore, Cameron; Staples, Orion

    2017-10-10

    Disclosed herein are embodiments of a method for making fuels and feedstocks from readily available alcohol starting materials. In some embodiments, the method concerns converting alcohols to carbonyl-containing compounds and then condensing such carbonyl-containing compounds together to form oligomerized species. These oligomerized species can then be reduced using by-products from the conversion of the alcohol. In some embodiments, the method further comprises converting saturated, oligomerized, carbonyl-containing compounds to aliphatic fuels.

  19. Process for purifying lignocellulosic feedstocks

    Energy Technology Data Exchange (ETDEWEB)

    Gray, Matthew; Matthes, Megan; Nelson, Thomas; Held, Andrew

    2018-01-09

    The present invention includes methods for removing mineral acids, mineral salts and contaminants, such as metal impurities, ash, terpenoids, stilbenes, flavonoids, proteins, and other inorganic products, from a lignocellulosic feedstock stream containing organic acids, carbohydrates, starches, polysaccharides, disaccharides, monosaccharides, sugars, sugar alcohols, phenols, cresols, and other oxygenated hydrocarbons, in a manner that maintains a portion of the organic acids and other oxygenated hydrocarbons in the product stream.

  20. Preparation of SS316L MIM feedstock with biopolymer as a binder

    Science.gov (United States)

    Abdullah, A. A.; Norita, H.; Azlina, H. N.; Sulong, A. B.; Mas’ood, N. N.

    2018-01-01

    This paper focus on feedstock preparation for SS316L metal injection molding (MIM) part. The primary step of feedstock preparation, critical powder loading determined by two method; maximum filled volume calculation model and torque analysis. The critical powder loading determined by calculation was 70 vol% to 77 vol% while for experimental approaches shows the value of 75 vol%. The feedstock was prepared by mixing SS316L powder and polymer binder with ratio 70:30 at 175 °C with speed of 50 rpm. The feedstock was analyzed by thermogravimetric analysis (TGA) and Scanning electron microscope (SEM). The composition for the feedstock after preparation step was confirmed by TGA. It was found that the prepared feedstock component was compatible to each other and composition is maintain along the mixing step.

  1. Development and Calibration of an Item Response Model That Incorporates Response Time

    Science.gov (United States)

    Wang, Tianyou; Hanson, Bradley H.

    2005-01-01

    This article proposes an item response model that incorporates response time. A parameter estimation procedure using the EM algorithm is developed. The procedure is evaluated with both real and simulated test data. The results suggest that the estimation procedure works well in estimating model parameters. By using response time data, estimation…

  2. Why did the price of solar PV Si feedstock fluctuate so wildly in 2004–2009?

    International Nuclear Information System (INIS)

    Yu Yang; Song Yuhua; Bao Haibo

    2012-01-01

    Great attention has been paid to the origin of observed wild price fluctuations of solar PV Si feedstock in both contract and spot markets during 2004–2009. This paper sheds light on this issue and tries to resolve it by addressing the following questions: what kind of structural shock is underlying the price fluctuations of PV Si feedstock? How can we quantify the magnitude, timing and relative importance of these shocks? What are their dynamic effects on the real price of PV Si feedstock? By carefully studying development conditions, the structural decomposition of the real price of PV Si feedstock is proposed: exchange rate shocks, production cost shocks, aggregate demand shocks and demand shocks specific to feedstock markets. With a Structural Vector Autoregression model, the paper quantifies and verifies the impact of structural shocks on PV Si feedstock real price changes. Based on national data, an analysis is further taken to confirm the essential role of demand shocks specific to feedstock markets in determining sharper price fluctuations during 2004–2009. The results of this study have important implications for national solar PV development, which can be better promoted and administrated if structural shocks in feedstock markets can be carefully evaluated and understood. - Highlights: ► The determination of solar PV Si feedstock price fluctuation is identified and quantified. ► Systematic structural shocks well explain 2004–2009 price fluctuations of PV Si feedstock. ► Production cost and aggregated demand shocks take longer effects on feedstock price. ► Exchange rate and feedstock specific demand shocks explain sharper price fluctuations. ► Development of national PV power should consider effects of structure shocks.

  3. Interfacing feedstock logistics with bioenergy conversion

    Energy Technology Data Exchange (ETDEWEB)

    Sokhansanj, S. [British Columbia Univ., Vancouver, BC (Canada). Oak Ridge National Lab

    2010-07-01

    The interface between biomass production and biomass conversion platforms was investigated. Functional relationships were assembled in a modeling platform to simulate the flow of biomass feedstock from farm and forest to a densification plant. The model considers key properties of biomass for downstream pre-processing and conversion. These properties include moisture content, cellulose, hemicelluloses, lignin, ash, particle size, specific density and bulk density. The model simulates logistical operations such as grinding to convert biomass to pellets that are supplied to a biorefinery for conversion to heat, power, or biofuels. Equations were developed to describe the physical aspects of each unit operation. The effect that each of the process variables has on the efficiency of the conversion processes was described.

  4. Ecological sustainability of alternative biomass feedstock production for environmental benefits and bioenergy

    Science.gov (United States)

    Ronald S., Jr. Zalesny; Jill A. Zalesny; Edmund O. Bauer

    2007-01-01

    The incorporation of intensive forestry with waste management fills a much-needed niche throughout numerous phytotechnology applications. There is a growing opportunity to incorporate sustainable recycling of waste waters as irrigation and fertilization for alternative biomass feedstock production systems. However, the success of short rotation woody crops is largely...

  5. A Bayesian model for pooling gene expression studies that incorporates co-regulation information.

    Directory of Open Access Journals (Sweden)

    Erin M Conlon

    Full Text Available Current Bayesian microarray models that pool multiple studies assume gene expression is independent of other genes. However, in prokaryotic organisms, genes are arranged in units that are co-regulated (called operons. Here, we introduce a new Bayesian model for pooling gene expression studies that incorporates operon information into the model. Our Bayesian model borrows information from other genes within the same operon to improve estimation of gene expression. The model produces the gene-specific posterior probability of differential expression, which is the basis for inference. We found in simulations and in biological studies that incorporating co-regulation information improves upon the independence model. We assume that each study contains two experimental conditions: a treatment and control. We note that there exist environmental conditions for which genes that are supposed to be transcribed together lose their operon structure, and that our model is best carried out for known operon structures.

  6. Synthetic carbonaceous fuels and feedstocks

    Science.gov (United States)

    Steinberg, Meyer

    1980-01-01

    This invention relates to the use of a three compartment electrolytic cell in the production of synthetic carbonaceous fuels and chemical feedstocks such as gasoline, methane and methanol by electrolyzing an aqueous sodium carbonate/bicarbonate solution, obtained from scrubbing atmospheric carbon dioxide with an aqueous sodium hydroxide solution, whereby the hydrogen generated at the cathode and the carbon dioxide liberated in the center compartment are combined thermocatalytically into methanol and gasoline blends. The oxygen generated at the anode is preferably vented into the atmosphere, and the regenerated sodium hydroxide produced at the cathode is reused for scrubbing the CO.sub.2 from the atmosphere.

  7. More valuable as petrochemical feedstock

    International Nuclear Information System (INIS)

    Ramachandran, R.

    2005-01-01

    The problems facing the North American petrochemical industry were discussed with particular reference to the fact that high North American prices present a challenge to competitiveness in a globally traded market. A background of Dow Canada was provided, including details of its upgrading of natural gas liquids that would otherwise be combusted for electrical power generation. The value of the petrochemical industry was outlined, with details of employment, manufacturing output and exports. Alberta's relationship to the natural gas industry was reviewed. The role of petrochemicals as a nexus for bridging the resource sector with manufacturing, retail and transportation was discussed. The historic correlation between world Gross Domestic Product (GDP) and ethylene demand was presented. It was noted that the petrochemical industry currently competes with power generators for smaller volumes of natural gas liquids. As a highly energy intensive industry, inequities in gas pipeline haul charges and even small increases in gas prices has compromised the success of the petrochemical industry. It was noted that while crude oil is a globally traded commodity, natural gas liquids are generally traded at a more localized level, and factors that helped build the petrochemical industry and are now inhibiting growth. Ethane is the primary feedstock in the petrochemical industry. High natural gas prices affected the industry on two levels: volatility in a weakening industry and higher prices on primary feedstocks. It was estimated that changes in current trends were likely to take place in 5 to 10 years, following Northern gas developments. It was estimated that more than 50 per cent of new capacity investment in ethylene plants would take place in the Middle East in the next 5 years. No new plants are planned in Canada. It was concluded that low-cost feedstock advantages, as well as alternative feedstocks and the sustainment of a healthy industry are necessary for the

  8. Incorporation of the capillary hysteresis model HYSTR into the numerical code TOUGH

    International Nuclear Information System (INIS)

    Niemi, A.; Bodvarsson, G.S.; Pruess, K.

    1991-11-01

    As part of the work performed to model flow in the unsaturated zone at Yucca Mountain Nevada, a capillary hysteresis model has been developed. The computer program HYSTR has been developed to compute the hysteretic capillary pressure -- liquid saturation relationship through interpolation of tabulated data. The code can be easily incorporated into any numerical unsaturated flow simulator. A complete description of HYSTR, including a brief summary of the previous hysteresis literature, detailed description of the program, and instructions for its incorporation into a numerical simulator are given in the HYSTR user's manual (Niemi and Bodvarsson, 1991a). This report describes the incorporation of HYSTR into the numerical code TOUGH (Transport of Unsaturated Groundwater and Heat; Pruess, 1986). The changes made and procedures for the use of TOUGH for hysteresis modeling are documented

  9. Autotrophic biorefinery: dawn of the gaseous carbon feedstock.

    Science.gov (United States)

    Butti, Sai Kishore; Mohan, S Venkata

    2017-10-02

    CO2 is a resource yet to be effectively utilized in the autotrophic biotechnology, not only to mitigate and moderate the anthropogenic influence on our climate, but also to steer CO2 sequestration for sustainable development and carbon neutral status. The atmospheric CO2 concentration has seen an exponential increase with the turn of the new millennia causing numerous environmental issues and also in a way feedstock crisis. To progressively regulate the growing CO2 concentrations and to incorporate the integration strategies to our existing CO2 capturing tools, all the influencing factors need to be collectively considered. The review article puts forth the change in perception of CO2 from which was once considered a harmful pollutant having deleterious effects to a renewable carbon source bearing the potential to replace the fossils as the carbon source through an autotrophic biorefinery. Here, we review the current methods employed for CO2 storage and capture, the need to develop sustainable methods and the ways of improving the sequestration efficiencies by various novice technologies. The review also provides an autotrophic biorefinery model with the potential to operate and produces a multitude of biobased products analogous to the petroleum refinery to establish a circular bioeconomy. Furthermore, fundamental and applied research niches that merit further research are delineated. © FEMS 2017. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

  10. Simulation of Forest Carbon Fluxes Using Model Incorporation and Data Assimilation

    OpenAIRE

    Min Yan; Xin Tian; Zengyuan Li; Erxue Chen; Xufeng Wang; Zongtao Han; Hong Sun

    2016-01-01

    This study improved simulation of forest carbon fluxes in the Changbai Mountains with a process-based model (Biome-BGC) using incorporation and data assimilation. Firstly, the original remote sensing-based MODIS MOD_17 GPP (MOD_17) model was optimized using refined input data and biome-specific parameters. The key ecophysiological parameters of the Biome-BGC model were determined through the Extended Fourier Amplitude Sensitivity Test (EFAST) sensitivity analysis. Then the optimized MOD_17 mo...

  11. Security of feedstocks supply for future bio-ethanol production in Thailand

    International Nuclear Information System (INIS)

    Silalertruksa, Thapat; Gheewala, Shabbir H.

    2010-01-01

    This study assesses the security of feedstock supply to satisfy the increased demand for bio-ethanol production based on the recent 15 years biofuels development plan and target (year 2008-2022) of the Thai government. Future bio-ethanol systems are modeled and the feedstock supply potentials analyzed based on three scenarios including low-, moderate- and high-yields improvement. The three scenarios are modeled and key dimensions including availability; diversity; and environmental acceptability of feedstocks supply in terms of GHG reduction are evaluated through indicators such as net feedstock balances, Shannon index and net life cycle GHG emissions. The results show that only the case of high yields improvement scenario can result in a reliable and sufficient supply of feedstocks to satisfy the long-term demands for bio-ethanol and other related industries. Cassava is identified as the critical feedstock and a reduction in cassava export is necessary. The study concludes that to enhance long-term security of feedstocks supply for sustainable bio-ethanol production in Thailand, increasing use of sugarcane juice as feedstock, improved yields of existing feedstocks and promoting production of bio-ethanol derived from agricultural residues are three key recommendations that need to be urgently implemented by the policy makers. - Research highlights: →Bioethanol in Thailand derived from molasses, cassava, sugarcane juice could yield reductions of 64%, 49% and 87% in GHGs when compared to conventional gasoline. →High yields improvement are required for a reliable and sufficient supply of molasses, cassava and sugarcane to satisfy the long-term demands for bio-ethanol and other related industries. →Other factors to enhance long-term security of feedstocks supply for sustainable bioethanol production in Thailand include increasing use of sugarcane juice as feedstock and promoting production of bioethanol derived from agricultural residues.

  12. A new experimental procedure for incorporation of model contaminants in polymer hosts

    NARCIS (Netherlands)

    Papaspyrides, C.D.; Voultzatis, Y.; Pavlidou, S.; Tsenoglou, C.; Dole, P.; Feigenbaum, A.; Paseiro, P.; Pastorelli, S.; Cruz Garcia, C. de la; Hankemeier, T.; Aucejo, S.

    2005-01-01

    A new experimental procedure for incorporation of model contaminants in polymers was developed as part of a general scheme for testing the efficiency of functional barriers in food packaging. The aim was to progressively pollute polymers in a controlled fashion up to a high level in the range of

  13. Flux Balance Analysis Indicates that Methane Is the Lowest Cost Feedstock for Microbial Cell Factories.

    Science.gov (United States)

    Comer, Austin D; Long, Matthew R; Reed, Jennifer L; Pfleger, Brian F

    2017-12-01

    The low cost of natural gas has driven significant interest in using C 1 carbon sources (e.g. methane, methanol, CO, syngas) as feedstocks for producing liquid transportation fuels and commodity chemicals. Given the large contribution of sugar and lignocellulosic feedstocks to biorefinery operating costs, natural gas and other C1 sources may provide an economic advantage. To assess the relative costs of these feedstocks, we performed flux balance analysis on genome-scale metabolic models to calculate the maximum theoretical yields of chemical products from methane, methanol, acetate, and glucose. Yield calculations were performed for every metabolite (as a proxy for desired products) in the genome-scale metabolic models of three organisms: Escherichia coli (bacterium), Saccharomyces cerevisiae (yeast), and Synechococcus sp. PCC 7002 (cyanobacterium). The calculated theoretical yields and current feedstock prices provided inputs to create comparative feedstock cost surfaces. Our analysis shows that, at current market prices, methane feedstock costs are consistently lower than glucose when used as a carbon and energy source for microbial chemical production. Conversely, methanol is costlier than glucose under almost all price scenarios. Acetate feedstock costs could be less than glucose given efficient acetate production from low-cost syngas using nascent biological gas to liquids (BIO-GTL) technologies. Our analysis suggests that research should focus on overcoming the technical challenges of methane assimilation and/or yield of acetate via BIO-GTL to take advantage of low-cost natural gas rather than using methanol as a feedstock.

  14. Flux balance analysis indicates that methane is the lowest cost feedstock for microbial cell factories

    Directory of Open Access Journals (Sweden)

    Austin D. Comer

    2017-12-01

    Full Text Available The low cost of natural gas has driven significant interest in using C1 carbon sources (e.g. methane, methanol, CO, syngas as feedstocks for producing liquid transportation fuels and commodity chemicals. Given the large contribution of sugar and lignocellulosic feedstocks to biorefinery operating costs, natural gas and other C1 sources may provide an economic advantage. To assess the relative costs of these feedstocks, we performed flux balance analysis on genome-scale metabolic models to calculate the maximum theoretical yields of chemical products from methane, methanol, acetate, and glucose. Yield calculations were performed for every metabolite (as a proxy for desired products in the genome-scale metabolic models of three organisms: Escherichia coli (bacterium, Saccharomyces cerevisiae (yeast, and Synechococcus sp. PCC 7002 (cyanobacterium. The calculated theoretical yields and current feedstock prices provided inputs to create comparative feedstock cost surfaces. Our analysis shows that, at current market prices, methane feedstock costs are consistently lower than glucose when used as a carbon and energy source for microbial chemical production. Conversely, methanol is costlier than glucose under almost all price scenarios. Acetate feedstock costs could be less than glucose given efficient acetate production from low-cost syngas using nascent biological gas to liquids (BIO-GTL technologies. Our analysis suggests that research should focus on overcoming the technical challenges of methane assimilation and/or yield of acetate via BIO-GTL to take advantage of low-cost natural gas rather than using methanol as a feedstock.

  15. INCORPORATING MULTIPLE OBJECTIVES IN PLANNING MODELS OF LOW-RESOURCE FARMERS

    OpenAIRE

    Flinn, John C.; Jayasuriya, Sisira; Knight, C. Gregory

    1980-01-01

    Linear goal programming provides a means of formally incorporating the multiple goals of a household into the analysis of farming systems. Using this approach, the set of plans which come as close as possible to achieving a set of desired goals under conditions of land and cash scarcity are derived for a Filipino tenant farmer. A challenge in making LGP models empirically operational is the accurate definition of the goals of the farm household being modelled.

  16. Evolution and Development of Effective Feedstock Specifications

    Energy Technology Data Exchange (ETDEWEB)

    Garold Gresham; Rachel Emerson; Amber Hoover; Amber Miller; William Bauer; Kevin Kenney

    2013-09-01

    The U.S. Department of Energy promotes the production of a range of liquid fuels and fuel blend stocks from lignocellulosic biomass feedstocks by funding fundamental and applied research that advances the state of technology in biomass collection, conversion, and sustainability. As part of its involvement in this program, the Idaho National Laboratory (INL) investigates the feedstock logistics economics and sustainability of these fuels. The 2012 feedstock logistics milestone demonstrated that for high-yield areas that minimize the transportation distances of a low-density, unstable biomass, we could achieve a delivered cost of $35/ton. Based on current conventional equipment and processes, the 2012 logistics design is able to deliver the volume of biomass needed to fulfill the 2012 Renewable Fuel Standard’s targets for ethanol. However, the Renewable Fuel Standard’s volume targets are continuing to increase and are expected to peak in 2022 at 36 billion gallons. Meeting these volume targets and achieving a national-scale biofuels industry will require expansion of production capacity beyond the 2012 Conventional Feedstock Supply Design Case to access diverse available feedstocks, regardless of their inherent ability to meet preliminary biorefinery quality feedstock specifications. Implementation of quality specifications (specs), as outlined in the 2017 Design Case – “Feedstock Supply System Design and Economics for Conversion of Lignocellulosic Biomass to Hydrocarbon Fuels” (in progress), requires insertion of deliberate, active quality controls into the feedstock supply chain, whereas the 2012 Conventional Design only utilizes passive quality controls.

  17. Mixed Culture PHA Production With Alternating Feedstocks

    DEFF Research Database (Denmark)

    Oliveira, C.S.S.; Duque, A.F.; Carvalho, Gilda

    selection stage, and a PHA production phase. This work investigated the performance robustness and microbial population dynamics of a PHA producing MMC when subjected to a feedstock shift, mimicking a seasonal feedstock scenario, from cheese whey to sugar cane molasses. Research was focused...

  18. Impact of Mixed Feedstocks and Feedstock Densification on Ionic Liquid Pretreatment Efficiency

    Energy Technology Data Exchange (ETDEWEB)

    Jian Shi; Vicki S. Thompson; Neal A. Yancey; Vitalie Stavila; Blake A. Simmons; Seema Singh

    2013-01-01

    Background: Lignocellulosic biorefineries must be able to efficiently process the regional feedstocks that are available at cost-competitive prices year round. These feedstocks typically have low energy densities and vary significantly in composition. One potential solution to these issues is blending and/or densifying the feedstocks in order to create a uniform feedstock. Results/discussion: We have mixed four feedstocks - switchgrass, lodgepole pine, corn stover, and eucalyptus - in flour and pellet form and processed them using the ionic liquid 1-ethyl-3-methylimidazolium acetate. Sugar yields from both the mixed flour and pelletized feedstocks reach 90% within 24 hours of saccharification. Conclusions: Mixed feedstocks, in either flour or pellet form, are efficiently processed using this pretreatment process, and demonstrate that this approach has significant potential.

  19. Incorporation of all hazard categories into U.S. NRC PRA models

    International Nuclear Information System (INIS)

    Sancaktar, Selim; Ferrante, Fernando; Siu, Nathan; Coyne, Kevin

    2014-01-01

    Over the last two decades, the U.S. Nuclear Regulatory Commission (NRC) has maintained independent probabilistic risk assessment (PRA) models to calculate nuclear power plant (NPP) core damage frequency (CDF) from internal events at power. These models are known as Standardized Plan Analysis Risk (SPAR) models. There are 79 such models representing 104 domestic nuclear plants; with some SPAR models representing more than one unit on the site. These models allow the NRC risk analysts to perform independent quantitative risk estimates of operational events and degraded plant conditions. It is well recognized that using only the internal events contribution to overall plant risk estimates provides a useful, but limited, assessment of the complete plant risk profile. Inclusion, of all hazard categories applicable to a plant in the plant PRA model would provide a more comprehensive assessment of a plant risk. However, implementation of a more comprehensive treatment of additional hazard categories (e.g., fire, flooding, high winds, seismic) presents a number of challenges, including technical considerations. The U.S. NRC has been incorporating additional hazard categories into its set of nuclear power plant PRA models since 2004. Currently, 18 SPAR models include additional hazard categories such as internal flooding, internal fire, seismic, and wind events. In most cases, these external hazard models were derived from Generic Letter 88-20 Individual Plant Examination of External Events (IPEEE) reports. Recently, NRC started incorporating detailed Fire PRA (FPRA) information based on the current licensing effort that allows licensees to transition into a risk-informed fire protection framework, as well as additional external hazards developed by some licensees into enhanced SPAR models. These updated external hazards SPAR models are referred to as SPAR All-Hazard (SPAR-AHZ) models (i.e., they incorporate additional risk contributors beyond internal events). This paper

  20. In silico investigation of the short QT syndrome, using human ventricle models incorporating electromechanical coupling

    Directory of Open Access Journals (Sweden)

    Ismail eAdeniran

    2013-07-01

    Full Text Available Introduction Genetic forms of the Short QT Syndrome (SQTS arise due to cardiac ion channel mutations leading to accelerated ventricular repolarisation, arrhythmias and sudden cardiac death. Results from experimental and simulation studies suggest that changes to refractoriness and tissue vulnerability produce a substrate favourable to re-entry. Potential electromechanical consequences of the SQTS are less well understood. The aim of this study was to utilize electromechanically coupled human ventricle models to explore electromechanical consequences of the SQTS. Methods and results: The Rice et al. mechanical model was coupled to the ten Tusscher et al. ventricular cell model. Previously validated K+ channel formulations for SQT variants 1 and 3 were incorporated. Functional effects of the SQTS mutations on transients, sarcomere length shortening and contractile force at the single cell level were evaluated with and without the consideration of stretch activated channel current (Isac. Without Isac, the SQTS mutations produced dramatic reductions in the amplitude of transients, sarcomere length shortening and contractile force. When Isac was incorporated, there was a considerable attenuation of the effects of SQTS-associated action potential shortening on Ca2+ transients, sarcomere shortening and contractile force. Single cell models were then incorporated into 3D human ventricular tissue models. The timing of maximum deformation was delayed in the SQTS setting compared to control. Conclusion: The incorporation of Isac appears to be an important consideration in modelling functional effects of SQT 1 and 3 mutations on cardiac electro-mechanical coupling. Whilst there is little evidence of profoundly impaired cardiac contractile function in SQTS patients, our 3D simulations correlate qualitatively with reported evidence for dissociation between ventricular repolarization and the end of mechanical systole.

  1. Improving Watershed-Scale Hydrodynamic Models by Incorporating Synthetic 3D River Bathymetry Network

    Science.gov (United States)

    Dey, S.; Saksena, S.; Merwade, V.

    2017-12-01

    Digital Elevation Models (DEMs) have an incomplete representation of river bathymetry, which is critical for simulating river hydrodynamics in flood modeling. Generally, DEMs are augmented with field collected bathymetry data, but such data are available only at individual reaches. Creating a hydrodynamic model covering an entire stream network in the basin requires bathymetry for all streams. This study extends a conceptual bathymetry model, River Channel Morphology Model (RCMM), to estimate the bathymetry for an entire stream network for application in hydrodynamic modeling using a DEM. It is implemented at two large watersheds with different relief and land use characterizations: coastal Guadalupe River basin in Texas with flat terrain and a relatively urban White River basin in Indiana with more relief. After bathymetry incorporation, both watersheds are modeled using HEC-RAS (1D hydraulic model) and Interconnected Pond and Channel Routing (ICPR), a 2-D integrated hydrologic and hydraulic model. A comparison of the streamflow estimated by ICPR at the outlet of the basins indicates that incorporating bathymetry influences streamflow estimates. The inundation maps show that bathymetry has a higher impact on flat terrains of Guadalupe River basin when compared to the White River basin.

  2. Commensurate Priors for Incorporating Historical Information in Clinical Trials Using General and Generalized Linear Models

    Science.gov (United States)

    Hobbs, Brian P.; Sargent, Daniel J.; Carlin, Bradley P.

    2014-01-01

    Assessing between-study variability in the context of conventional random-effects meta-analysis is notoriously difficult when incorporating data from only a small number of historical studies. In order to borrow strength, historical and current data are often assumed to be fully homogeneous, but this can have drastic consequences for power and Type I error if the historical information is biased. In this paper, we propose empirical and fully Bayesian modifications of the commensurate prior model (Hobbs et al., 2011) extending Pocock (1976), and evaluate their frequentist and Bayesian properties for incorporating patient-level historical data using general and generalized linear mixed regression models. Our proposed commensurate prior models lead to preposterior admissible estimators that facilitate alternative bias-variance trade-offs than those offered by pre-existing methodologies for incorporating historical data from a small number of historical studies. We also provide a sample analysis of a colon cancer trial comparing time-to-disease progression using a Weibull regression model. PMID:24795786

  3. Incorporating Pass-Phrase Dependent Background Models for Text-Dependent Speaker verification

    DEFF Research Database (Denmark)

    Sarkar, Achintya Kumar; Tan, Zheng-Hua

    2018-01-01

    is compared to conventional text-independent background model based TD-SV systems using either Gaussian mixture model (GMM)-universal background model (UBM) or Hidden Markov model (HMM)-UBM or i-vector paradigms. In addition, we consider two approaches to build PBMs: speaker-independent and speaker......In this paper, we propose pass-phrase dependent background models (PBMs) for text-dependent (TD) speaker verification (SV) to integrate the pass-phrase identification process into the conventional TD-SV system, where a PBM is derived from a text-independent background model through adaptation using...... and the selected PBM is then used for the log likelihood ratio (LLR) calculation with respect to the claimant model. The proposed method incorporates the pass-phrase identification step in the LLR calculation, which is not considered in conventional standalone TD-SV systems. The performance of the proposed method...

  4. Incorporating Mobility in Growth Modeling for Multilevel and Longitudinal Item Response Data.

    Science.gov (United States)

    Choi, In-Hee; Wilson, Mark

    2016-01-01

    Multilevel data often cannot be represented by the strict form of hierarchy typically assumed in multilevel modeling. A common example is the case in which subjects change their group membership in longitudinal studies (e.g., students transfer schools; employees transition between different departments). In this study, cross-classified and multiple membership models for multilevel and longitudinal item response data (CCMM-MLIRD) are developed to incorporate such mobility, focusing on students' school change in large-scale longitudinal studies. Furthermore, we investigate the effect of incorrectly modeling school membership in the analysis of multilevel and longitudinal item response data. Two types of school mobility are described, and corresponding models are specified. Results of the simulation studies suggested that appropriate modeling of the two types of school mobility using the CCMM-MLIRD yielded good recovery of the parameters and improvement over models that did not incorporate mobility properly. In addition, the consequences of incorrectly modeling the school effects on the variance estimates of the random effects and the standard errors of the fixed effects depended upon mobility patterns and model specifications. Two sets of large-scale longitudinal data are analyzed to illustrate applications of the CCMM-MLIRD for each type of school mobility.

  5. Gold Incorporated Mesoporous Silica Thin Film Model Surface as a Robust SERS and Catalytically Active Substrate

    Directory of Open Access Journals (Sweden)

    Anandakumari Chandrasekharan Sunil Sekhar

    2016-05-01

    Full Text Available Ultra-small gold nanoparticles incorporated in mesoporous silica thin films with accessible pore channels perpendicular to the substrate are prepared by a modified sol-gel method. The simple and easy spin coating technique is applied here to make homogeneous thin films. The surface characterization using FESEM shows crack-free films with a perpendicular pore arrangement. The applicability of these thin films as catalysts as well as a robust SERS active substrate for model catalysis study is tested. Compared to bare silica film our gold incorporated silica, GSM-23F gave an enhancement factor of 103 for RhB with a laser source 633 nm. The reduction reaction of p-nitrophenol with sodium borohydride from our thin films shows a decrease in peak intensity corresponding to –NO2 group as time proceeds, confirming the catalytic activity. Such model surfaces can potentially bridge the material gap between a real catalytic system and surface science studies.

  6. Microfluidic vascularized bone tissue model with hydroxyapatite-incorporated extracellular matrix.

    Science.gov (United States)

    Jusoh, Norhana; Oh, Soojung; Kim, Sudong; Kim, Jangho; Jeon, Noo Li

    2015-10-21

    Current in vitro systems mimicking bone tissues fail to fully integrate the three-dimensional (3D) microvasculature and bone tissue microenvironments, decreasing their similarity to in vivo conditions. Here, we propose 3D microvascular networks in a hydroxyapatite (HA)-incorporated extracellular matrix (ECM) for designing and manipulating a vascularized bone tissue model in a microfluidic device. Incorporation of HA of various concentrations resulted in ECM with varying mechanical properties. Sprouting angiogenesis was affected by mechanically modulated HA-extracellular matrix interactions, generating a model of vascularized bone microenvironment. Using this platform, we observed that hydroxyapatite enhanced angiogenic properties such as sprout length, sprouting speed, sprout number, and lumen diameter. This new platform integrates fibrin ECM with the synthetic bone mineral HA to provide in vivo-like microenvironments for bone vessel sprouting.

  7. Modeling fraud detection and the incorporation of forensic specialists in the audit process

    DEFF Research Database (Denmark)

    Sakalauskaite, Dominyka

    Financial statement audits are still comparatively poor in fraud detection. Forensic specialists can play a significant role in increasing audit quality. In this paper, based on prior academic research, I develop a model of fraud detection and the incorporation of forensic specialists in the audit...... process. The intention of the model is to identify the reasons why the audit is weak in fraud detection and to provide the analytical framework to assess whether the incorporation of forensic specialists can help to improve it. The results show that such specialists can potentially improve the fraud...... detection in the audit, but might also cause some negative implications. Overall, even though fraud detection is one of the main topics in research there are very few studies done on the subject of how auditors co-operate with forensic specialists. Thus, the paper concludes with suggestions for further...

  8. The Aerosol Models in MODTRAN: Incorporating Selected Measurements From Northern Australia

    Science.gov (United States)

    2005-12-01

    of atmospheric aerosol obtained around Jabiru , N.T., in June and September 2003. These measurements are used to obtain theoretical multimode size...coefficients. The attenuation coefficients are then incorporated into MODTRAN and compared with the default aerosol models. Finally the Jabiru aerosol is...centred on Jabiru in the Northern Territory, Australia. This environment is typical of a Northern Australian dry season climate. Atmospheric transmission

  9. Multi-model inference for incorporating trophic and climate uncertainty into stock assessments

    Science.gov (United States)

    Ianelli, James; Holsman, Kirstin K.; Punt, André E.; Aydin, Kerim

    2016-12-01

    Ecosystem-based fisheries management (EBFM) approaches allow a broader and more extensive consideration of objectives than is typically possible with conventional single-species approaches. Ecosystem linkages may include trophic interactions and climate change effects on productivity for the relevant species within the system. Presently, models are evolving to include a comprehensive set of fishery and ecosystem information to address these broader management considerations. The increased scope of EBFM approaches is accompanied with a greater number of plausible models to describe the systems. This can lead to harvest recommendations and biological reference points that differ considerably among models. Model selection for projections (and specific catch recommendations) often occurs through a process that tends to adopt familiar, often simpler, models without considering those that incorporate more complex ecosystem information. Multi-model inference provides a framework that resolves this dilemma by providing a means of including information from alternative, often divergent models to inform biological reference points and possible catch consequences. We apply an example of this approach to data for three species of groundfish in the Bering Sea: walleye pollock, Pacific cod, and arrowtooth flounder using three models: 1) an age-structured "conventional" single-species model, 2) an age-structured single-species model with temperature-specific weight at age, and 3) a temperature-specific multi-species stock assessment model. The latter two approaches also include consideration of alternative future climate scenarios, adding another dimension to evaluate model projection uncertainty. We show how Bayesian model-averaging methods can be used to incorporate such trophic and climate information to broaden single-species stock assessments by using an EBFM approach that may better characterize uncertainty.

  10. Stochastic modelling of landfill processes incorporating waste heterogeneity and data uncertainty

    International Nuclear Information System (INIS)

    Zacharof, A.I.; Butler, A.P.

    2004-01-01

    A landfill is a very complex heterogeneous environment and as such it presents many modelling challenges. Attempts to develop models that reproduce these complexities generally involve the use of large numbers of spatially dependent parameters that cannot be properly characterised in the face of data uncertainty. An alternative method is presented, which couples a simplified microbial degradation model with a stochastic hydrological and contaminant transport model. This provides a framework for incorporating the complex effects of spatial heterogeneity within the landfill in a simplified manner, along with other key variables. A methodology for handling data uncertainty is also integrated into the model structure. Illustrative examples of the model's output are presented to demonstrate effects of data uncertainty on leachate composition and gas volume prediction

  11. Engineered plant biomass feedstock particles

    Science.gov (United States)

    Dooley, James H [Federal Way, WA; Lanning, David N [Federal Way, WA; Broderick, Thomas F [Lake Forest Park, WA

    2012-04-17

    A new class of plant biomass feedstock particles characterized by consistent piece size and shape uniformity, high skeletal surface area, and good flow properties. The particles of plant biomass material having fibers aligned in a grain are characterized by a length dimension (L) aligned substantially parallel to the grain and defining a substantially uniform distance along the grain, a width dimension (W) normal to L and aligned cross grain, and a height dimension (H) normal to W and L. In particular, the L.times.H dimensions define a pair of substantially parallel side surfaces characterized by substantially intact longitudinally arrayed fibers, the W.times.H dimensions define a pair of substantially parallel end surfaces characterized by crosscut fibers and end checking between fibers, and the L.times.W dimensions define a pair of substantially parallel top and bottom surfaces. The L.times.W surfaces of particles with L/H dimension ratios of 4:1 or less are further elaborated by surface checking between longitudinally arrayed fibers. The length dimension L is preferably aligned within 30.degree. parallel to the grain, and more preferably within 10.degree. parallel to the grain. The plant biomass material is preferably selected from among wood, agricultural crop residues, plantation grasses, hemp, bagasse, and bamboo.

  12. A Constitutive Model for Soft Clays Incorporating Elastic and Plastic Cross-Anisotropy.

    Science.gov (United States)

    Castro, Jorge; Sivasithamparam, Nallathamby

    2017-05-25

    Natural clays exhibit a significant degree of anisotropy in their fabric, which initially is derived from the shape of the clay platelets, deposition process and one-dimensional consolidation. Various authors have proposed anisotropic elastoplastic models involving an inclined yield surface to reproduce anisotropic behavior of plastic nature. This paper presents a novel constitutive model for soft structured clays that includes anisotropic behavior both of elastic and plastic nature. The new model incorporates stress-dependent cross-anisotropic elastic behavior within the yield surface using three independent elastic parameters because natural clays exhibit cross-anisotropic (or transversely isotropic) behavior after deposition and consolidation. Thus, the model only incorporates an additional variable with a clear physical meaning, namely the ratio between horizontal and vertical stiffnesses, which can be analytically obtained from conventional laboratory tests. The model does not consider evolution of elastic anisotropy, but laboratory results show that large strains are necessary to cause noticeable changes in elastic anisotropic behavior. The model is able to capture initial non-vertical effective stress paths for undrained triaxial tests and to predict deviatoric strains during isotropic loading or unloading.

  13. Incorporation of Markov reliability models for digital instrumentation and control systems into existing PRAs

    International Nuclear Information System (INIS)

    Bucci, P.; Mangan, L. A.; Kirschenbaum, J.; Mandelli, D.; Aldemir, T.; Arndt, S. A.

    2006-01-01

    Markov models have the ability to capture the statistical dependence between failure events that can arise in the presence of complex dynamic interactions between components of digital instrumentation and control systems. One obstacle to the use of such models in an existing probabilistic risk assessment (PRA) is that most of the currently available PRA software is based on the static event-tree/fault-tree methodology which often cannot represent such interactions. We present an approach to the integration of Markov reliability models into existing PRAs by describing the Markov model of a digital steam generator feedwater level control system, how dynamic event trees (DETs) can be generated from the model, and how the DETs can be incorporated into an existing PRA with the SAPHIRE software. (authors)

  14. A code reviewer assignment model incorporating the competence differences and participant preferences

    Directory of Open Access Journals (Sweden)

    Wang Yanqing

    2016-03-01

    Full Text Available A good assignment of code reviewers can effectively utilize the intellectual resources, assure code quality and improve programmers’ skills in software development. However, little research on reviewer assignment of code review has been found. In this study, a code reviewer assignment model is created based on participants’ preference to reviewing assignment. With a constraint of the smallest size of a review group, the model is optimized to maximize review outcomes and avoid the negative impact of “mutual admiration society”. This study shows that the reviewer assignment strategies incorporating either the reviewers’ preferences or the authors’ preferences get much improvement than a random assignment. The strategy incorporating authors’ preference makes higher improvement than that incorporating reviewers’ preference. However, when the reviewers’ and authors’ preference matrixes are merged, the improvement becomes moderate. The study indicates that the majority of the participants have a strong wish to work with reviewers and authors having highest competence. If we want to satisfy the preference of both reviewers and authors at the same time, the overall improvement of learning outcomes may be not the best.

  15. Incorporation of UK Met Office's radiation scheme into CPTEC's global model

    Science.gov (United States)

    Chagas, Júlio C. S.; Barbosa, Henrique M. J.

    2009-03-01

    Current parameterization of radiation in the CPTEC's (Center for Weather Forecast and Climate Studies, Cachoeira Paulista, SP, Brazil) operational AGCM has its origins in the work of Harshvardhan et al. (1987) and uses the formulation of Ramaswamy and Freidenreich (1992) for the short-wave absorption by water vapor. The UK Met Office's radiation code (Edwards and Slingo, 1996) was incorporated into CPTEC's global model, initially for short-wave only, and some impacts of that were shown by Chagas and Barbosa (2006). Current paper presents some impacts of the complete incorporation (both short-wave and long-wave) of UK Met Office's scheme. Selected results from off-line comparisons with line-by-line benchmark calculations are shown. Impacts on the AGCM's climate are assessed by comparing output of climate runs of current and modified AGCM with products from GEWEX/SRB (Surface Radiation Budget) project.

  16. Global dynamics of a PDE model for aedes aegypti mosquitoe incorporating female sexual preference

    KAUST Repository

    Parshad, Rana

    2011-01-01

    In this paper we study the long time dynamics of a reaction diffusion system, describing the spread of Aedes aegypti mosquitoes, which are the primary cause of dengue infection. The system incorporates a control attempt via the sterile insect technique. The model incorporates female mosquitoes sexual preference for wild males over sterile males. We show global existence of strong solution for the system. We then derive uniform estimates to prove the existence of a global attractor in L-2(Omega), for the system. The attractor is shown to be L-infinity(Omega) regular and posess state of extinction, if the injection of sterile males is large enough. We also provide upper bounds on the Hausdorff and fractal dimensions of the attractor.

  17. Upgrading of solid biofuels and feedstock quality

    Energy Technology Data Exchange (ETDEWEB)

    Burvall, Jan [Swedish Univ. of Agricultural Sciences, Umeaa (Sweden). Dept. of Agricultural Research for Northern Sweden

    1998-06-01

    This paper treats upgrading of biomass to pellets, briquettes and powder and the quality needed of the initial feedstock. The main raw materials are wood and reed canary grass (Phalaris arundinacea L.) 5 refs, 6 figs, 2 tabs

  18. 2011 Biomass Program Platform Peer Review: Feedstock

    Energy Technology Data Exchange (ETDEWEB)

    McCann, Laura [Office of Energy Efficiency and Renewable Energy (EERE), Washington, DC (United States)

    2012-02-01

    This document summarizes the recommendations and evaluations provided by an independent external panel of experts at the 2011 U.S. Department of Energy Biomass Program’s Feedstock Platform Review meeting.

  19. Incorporation of the Driver’s Personality Profile in an Agent Model

    Directory of Open Access Journals (Sweden)

    Mian Muhammad Mubasher

    2015-12-01

    Full Text Available Urban traffic flow is a complex system. Behavior of an individual driver can have butterfly effect which can become root cause of an emergent phenomenon such as congestion or accident. Interaction of drivers with each other and the surrounding environment forms the dynamics of traffic flow. Hence global effects of traffic flow depend upon the behavior of each individual driver. Due to several applications of driver models in serious games, urban traffic planning and simulations, study of a realistic driver model is important. Hhence cognitive models of a driver agent are required. In order to address this challenge concepts from cognitive science and psychology are employed to design a computational model of driver cognition which is capable of incorporating law abidance and social norms using big five personality profile.

  20. Incorporating grazing into an eco-hydrologic model: Simulating coupled human and natural systems in rangelands

    Science.gov (United States)

    Reyes, J. J.; Liu, M.; Tague, C.; Choate, J. S.; Evans, R. D.; Johnson, K. A.; Adam, J. C.

    2013-12-01

    Rangelands provide an opportunity to investigate the coupled feedbacks between human activities and natural ecosystems. These areas comprise at least one-third of the Earth's surface and provide ecological support for birds, insects, wildlife and agricultural animals including grazing lands for livestock. Capturing the interactions among water, carbon, and nitrogen cycles within the context of regional scale patterns of climate and management is important to understand interactions, responses, and feedbacks between rangeland systems and humans, as well as provide relevant information to stakeholders and policymakers. The overarching objective of this research is to understand the full consequences, intended and unintended, of human activities and climate over time in rangelands by incorporating dynamics related to rangeland management into an eco-hydrologic model that also incorporates biogeochemical and soil processes. Here we evaluate our model over ungrazed and grazed sites for different rangeland ecosystems. The Regional Hydro-ecologic Simulation System (RHESSys) is a process-based, watershed-scale model that couples water with carbon and nitrogen cycles. Climate, soil, vegetation, and management effects within the watershed are represented in a nested landscape hierarchy to account for heterogeneity and the lateral movement of water and nutrients. We incorporated a daily time-series of plant biomass loss from rangeland to represent grazing. The TRY Plant Trait Database was used to parameterize genera of shrubs and grasses in different rangeland types, such as tallgrass prairie, Intermountain West cold desert, and shortgrass steppe. In addition, other model parameters captured the reallocation of carbon and nutrients after grass defoliation. Initial simulations were conducted at the Curlew Valley site in northern Utah, a former International Geosphere-Biosphere Programme Desert Biome site. We found that grasses were most sensitive to model parameters affecting

  1. Incorporating microbiota data into epidemiologic models: examples from vaginal microbiota research.

    Science.gov (United States)

    van de Wijgert, Janneke H; Jespers, Vicky

    2016-05-01

    Next generation sequencing and quantitative polymerase chain reaction technologies are now widely available, and research incorporating these methods is growing exponentially. In the vaginal microbiota (VMB) field, most research to date has been descriptive. The purpose of this article is to provide an overview of different ways in which next generation sequencing and quantitative polymerase chain reaction data can be used to answer clinical epidemiologic research questions using examples from VMB research. We reviewed relevant methodological literature and VMB articles (published between 2008 and 2015) that incorporated these methodologies. VMB data have been analyzed using ecologic methods, methods that compare the presence or relative abundance of individual taxa or community compositions between different groups of women or sampling time points, and methods that first reduce the complexity of the data into a few variables followed by the incorporation of these variables into traditional biostatistical models. To make future VMB research more clinically relevant (such as studying associations between VMB compositions and clinical outcomes and the effects of interventions on the VMB), it is important that these methods are integrated with rigorous epidemiologic methods (such as appropriate study designs, sampling strategies, and adjustment for confounding). Crown Copyright © 2016. Published by Elsevier Inc. All rights reserved.

  2. Molding Properties of Inconel 718 Feedstocks Used in Low-Pressure Powder Injection Molding

    Directory of Open Access Journals (Sweden)

    Fouad Fareh

    2016-01-01

    Full Text Available The impact of binders and temperature on the rheological properties of feedstocks used in low-pressure powder injection molding was investigated. Experiments were conducted on different feedstock formulations obtained by mixing Inconel 718 powder with wax-based binder systems. The shear rate sensitivity index and the activation energy were used to study the degree of dependence of shear rate and temperature on the viscosity of the feedstocks. The injection performance of feedstocks was then evaluated using an analytical moldability model. The results indicated that the viscosity profiles of feedstocks depend significantly on the binder constituents, and the secondary binder constituents play an important role in the rheological behavior (pseudoplastic or near-Newtonian exhibited by the feedstock formulations. Viscosity values as low as 0.06 to 2.9 Pa·s were measured at high shear rates and high temperatures. The results indicate that a feedstock containing a surfactant agent exhibits the best moldability characteristics.

  3. Modified permeability modeling of coal incorporating sorption-induced matrix shrinkage

    Science.gov (United States)

    Soni, Aman

    The variation in the cleat permeability of coalbed methane (CBM) reservoirs is attributed primarily to two cardinal processes, with opposing effects. Increase in effective stresses with reduction in pore pressure tends to decrease the cleat permeability, whereas the sorption-induced coal matrix shrinkage actuates reduction in the effective stresses which increases the reservoir permeability. The net effect of the two processes determines the pressure-dependent-permeability and, hence, the overall trend of CBM production with depletion. Several analytical models have been developed and used to predict the dynamic behavior of CBM reservoir permeability during production through pressure depletion, all based on combining the two effects. The purpose of this study was to introduce modifications to two most commonly used permeability models, namely the Palmer and Mansoori, and Shi and Durucan, for permeability variation and evaluate their performance when projecting gas production. The basis for the modification is the linear relationship between the volume of sorbed gas and the associated matrix shrinkage. Hence, the impact of matrix shrinkage is incorporated as a function of the amount of gas produced, or that remaining in coal, at any time during production. Since the exact production from a reservoir is known throughout its life, this significantly simplifies the process of permeability modeling. Furthermore, the modification is also expected to streamline the process of modeling by classifying the shrinkage parameters for coals of different regions, but with similar characteristics. A good analogy is the San Juan basin, where sorption characteristics of coal are so well understood and defined that operators no longer carry out laboratory sorption work. The goal is to achieve the same for incorporation of the matrix shrinkage behavior. Another modification is to incorporate the matrix, or grain, compressibility effect of coal as a correction factor in the Shi and

  4. Teaching Genetic Counseling Skills: Incorporating a Genetic Counseling Adaptation Continuum Model to Address Psychosocial Complexity.

    Science.gov (United States)

    Shugar, Andrea

    2017-04-01

    Genetic counselors are trained health care professionals who effectively integrate both psychosocial counseling and information-giving into their practice. Preparing genetic counseling students for clinical practice is a challenging task, particularly when helping them develop effective and active counseling skills. Resistance to incorporating these skills may stem from decreased confidence, fear of causing harm or a lack of clarity of psycho-social goals. The author reflects on the personal challenges experienced in teaching genetic counselling students to work with psychological and social complexity, and proposes a Genetic Counseling Adaptation Continuum model and methodology to guide students in the use of advanced counseling skills.

  5. Incorporation of detailed eye model into polygon-mesh versions of ICRP-110 reference phantoms.

    Science.gov (United States)

    Nguyen, Thang Tat; Yeom, Yeon Soo; Kim, Han Sung; Wang, Zhao Jun; Han, Min Cheol; Kim, Chan Hyeong; Lee, Jai Ki; Zankl, Maria; Petoussi-Henss, Nina; Bolch, Wesley E; Lee, Choonsik; Chung, Beom Sun

    2015-11-21

    The dose coefficients for the eye lens reported in ICRP 2010 Publication 116 were calculated using both a stylized model and the ICRP-110 reference phantoms, according to the type of radiation, energy, and irradiation geometry. To maintain consistency of lens dose assessment, in the present study we incorporated the ICRP-116 detailed eye model into the converted polygon-mesh (PM) version of the ICRP-110 reference phantoms. After the incorporation, the dose coefficients for the eye lens were calculated and compared with those of the ICRP-116 data. The results showed generally a good agreement between the newly calculated lens dose coefficients and the values of ICRP 2010 Publication 116. Significant differences were found for some irradiation cases due mainly to the use of different types of phantoms. Considering that the PM version of the ICRP-110 reference phantoms preserve the original topology of the ICRP-110 reference phantoms, it is believed that the PM version phantoms, along with the detailed eye model, provide more reliable and consistent dose coefficients for the eye lens.

  6. Improving Estimates of Regional Infrasound Propagation by Incorporating Three-Dimensional Weather Modeling

    Science.gov (United States)

    McKenna, M. H.; Alter, R. E.; Swearingen, M. E.; Wilson, D. K.

    2017-12-01

    Many larger sources, such as volcanic eruptions and nuclear detonations, produce infrasound (acoustic waves with a frequency lower than humans can hear, namely 0.1-20 Hz) that can propagate over global scales. But many smaller infrastructure sources, such as bridges, dams, and buildings, also produce infrasound, though with a lower amplitude that tends to propagate only over regional scales (up to 150 km). In order to accurately calculate regional-scale infrasound propagation, we have incorporated high-resolution, three-dimensional forecasts from the Weather Research and Forecasting (WRF) meteorological model into a signal propagation modeling system called Environmental Awareness for Sensor and Emitter Employment (EASEE), developed at the US Army Engineer Research and Development Center. To quantify the improvement of infrasound propagation predictions with more realistic weather data, we conducted sensitivity studies with different propagation ranges and horizontal resolutions and compared them to default predictions with no weather model data. We describe the process of incorporating WRF output into EASEE for conducting these acoustic propagation simulations and present the results of the aforementioned sensitivity studies.

  7. Developing Baltic cod recruitment models II : Incorporation of environmental variability and species interaction

    DEFF Research Database (Denmark)

    Köster, Fritz; Hinrichsen, H.H.; St. John, Michael

    2001-01-01

    We investigate whether a process-oriented approach based on the results of field, laboratory, and modelling studies can be used to develop a stock-environment-recruitment model for Central Baltic cod (Gadus morhua). Based on exploratory statistical analysis, significant variables influencing...... affecting survival of eggs, predation by clupeids on eggs, larval transport, and cannibalism. Results showed that recruitment in the most important spawning area, the Bornholm Basin, during 1976-1995 was related to egg production; however, other factors affecting survival of the eggs (oxygen conditions......, predation) were also significant and when incorporated explained 69% of the variation in 0-group recruitment. In other spawning areas, variable hydrographic conditions did not allow for regular successful egg development. Hence, relatively simple models proved sufficient to predict recruitment of 0-group...

  8. A Fibrocontractive Mechanochemical Model of Dermal Wound Closure Incorporating Realistic Growth Factor Kinetics

    KAUST Repository

    Murphy, Kelly E.

    2012-01-13

    Fibroblasts and their activated phenotype, myofibroblasts, are the primary cell types involved in the contraction associated with dermal wound healing. Recent experimental evidence indicates that the transformation from fibroblasts to myofibroblasts involves two distinct processes: The cells are stimulated to change phenotype by the combined actions of transforming growth factor β (TGFβ) and mechanical tension. This observation indicates a need for a detailed exploration of the effect of the strong interactions between the mechanical changes and growth factors in dermal wound healing. We review the experimental findings in detail and develop a model of dermal wound healing that incorporates these phenomena. Our model includes the interactions between TGFβ and collagenase, providing a more biologically realistic form for the growth factor kinetics than those included in previous mechanochemical descriptions. A comparison is made between the model predictions and experimental data on human dermal wound healing and all the essential features are well matched. © 2012 Society for Mathematical Biology.

  9. Developing Baltic cod recruitment models II : Incorporation of environmental variability and species interaction

    DEFF Research Database (Denmark)

    Köster, Fritz; Hinrichsen, H.H.; St. John, Michael

    2001-01-01

    We investigate whether a process-oriented approach based on the results of field, laboratory, and modelling studies can be used to develop a stock-environment-recruitment model for Central Baltic cod (Gadus morhua). Based on exploratory statistical analysis, significant variables influencing...... survival of early life stages and varying systematically among spawning sites were incorporated into stock-recruitment models, first for major cod spawning sites and then combined for the entire Central Baltic. Variables identified included potential egg production by the spawning stock, abiotic conditions...... affecting survival of eggs, predation by clupeids on eggs, larval transport, and cannibalism. Results showed that recruitment in the most important spawning area, the Bornholm Basin, during 1976-1995 was related to egg production; however, other factors affecting survival of the eggs (oxygen conditions...

  10. Some considerations concerning the challenge of incorporating social variables into epidemiological models of infectious disease transmission.

    Science.gov (United States)

    Barnett, Tony; Fournié, Guillaume; Gupta, Sunetra; Seeley, Janet

    2015-01-01

    Incorporation of 'social' variables into epidemiological models remains a challenge. Too much detail and models cease to be useful; too little and the very notion of infection - a highly social process in human populations - may be considered with little reference to the social. The French sociologist Émile Durkheim proposed that the scientific study of society required identification and study of 'social currents'. Such 'currents' are what we might today describe as 'emergent properties', specifiable variables appertaining to individuals and groups, which represent the perspectives of social actors as they experience the environment in which they live their lives. Here we review the ways in which one particular emergent property, hope, relevant to a range of epidemiological situations, might be used in epidemiological modelling of infectious diseases in human populations. We also indicate how such an approach might be extended to include a range of other potential emergent properties to represent complex social and economic processes bearing on infectious disease transmission.

  11. Hydrogen production via catalytic processing of renewable feedstocks

    International Nuclear Information System (INIS)

    Nazim Muradov; Franklyn Smith; Ali T-Raissi

    2006-01-01

    Landfill gas (LFG) and biogas can potentially become important feedstocks for renewable hydrogen production. The objectives of this work were: (1) to develop a catalytic process for direct reforming of CH 4 -CO 2 gaseous mixture mimicking LFG, (2) perform thermodynamic analysis of the reforming process using AspenPlus chemical process simulator, (3) determine operational conditions for auto-thermal (or thermo-neutral) reforming of a model CH 4 -CO 2 feedstock, and (4) fabricate and test a bench-scale hydrogen production unit. Experimental data obtained from catalytic reformation of the CH 4 -CO 2 and CH 4 -CO 2 -O 2 gaseous mixtures using Ni-catalyst were in a good agreement with the simulation results. It was demonstrated that catalytic reforming of LFG-mimicking gas produced hydrogen with the purity of 99.9 vol.%. (authors)

  12. Incorporating remote sensing-based ET estimates into the Community Land Model version 4.5

    Science.gov (United States)

    Wang, Dagang; Wang, Guiling; Parr, Dana T.; Liao, Weilin; Xia, Youlong; Fu, Congsheng

    2017-07-01

    Land surface models bear substantial biases in simulating surface water and energy budgets despite the continuous development and improvement of model parameterizations. To reduce model biases, Parr et al. (2015) proposed a method incorporating satellite-based evapotranspiration (ET) products into land surface models. Here we apply this bias correction method to the Community Land Model version 4.5 (CLM4.5) and test its performance over the conterminous US (CONUS). We first calibrate a relationship between the observational ET from the Global Land Evaporation Amsterdam Model (GLEAM) product and the model ET from CLM4.5, and assume that this relationship holds beyond the calibration period. During the validation or application period, a simulation using the default CLM4.5 (CLM) is conducted first, and its output is combined with the calibrated observational-vs.-model ET relationship to derive a corrected ET; an experiment (CLMET) is then conducted in which the model-generated ET is overwritten with the corrected ET. Using the observations of ET, runoff, and soil moisture content as benchmarks, we demonstrate that CLMET greatly improves the hydrological simulations over most of the CONUS, and the improvement is stronger in the eastern CONUS than the western CONUS and is strongest over the Southeast CONUS. For any specific region, the degree of the improvement depends on whether the relationship between observational and model ET remains time-invariant (a fundamental hypothesis of the Parr et al. (2015) method) and whether water is the limiting factor in places where ET is underestimated. While the bias correction method improves hydrological estimates without improving the physical parameterization of land surface models, results from this study do provide guidance for physically based model development effort.

  13. Incorporating herd immunity effects into cohort models of vaccine cost-effectiveness.

    Science.gov (United States)

    Bauch, Chris T; Anonychuk, Andrea M; Van Effelterre, Thierry; Pham, Bá Z; Merid, Maraki Fikre

    2009-01-01

    Cohort models are often used in cost-effectiveness analysis (CEA) of vaccination. However, because they cannot capture herd immunity effects, cohort models underestimate the reduction in incidence caused by vaccination. Dynamic models capture herd immunity effects but are often not adopted in vaccine CEA. The objective was to develop a pseudo-dynamic approximation that can be incorporated into an existing cohort model to capture herd immunity effects. The authors approximated changing force of infection due to universal vaccination for a pediatric infectious disease. The projected lifetime cases in a cohort were compared under 1) a cohort model, 2) a cohort model with pseudo-dynamic approximation, and 3) an age-structured susceptible-exposed-infectious-recovered compartmental (dynamic) model. The authors extended the methodology to sexually transmitted infections. For average to high values of vaccine coverage (P > 60%) and small to average values of the basic reproduction number (R(0) vaccination programs for many common infections, the pseudo-dynamic approximation significantly improved projected lifetime cases and was close to projections of the full dynamic model. For large values of R(0) (R(0) > 15), projected lifetime cases were similar under the dynamic model and the cohort model, both with and without pseudo-dynamic approximation. The approximation captures changes in the mean age at infection in the 1st vaccinated cohort. This methodology allows for preliminary assessment of herd immunity effects on CEA of universal vaccination for pediatric infectious diseases. The method requires simple adjustments to an existing cohort model and less data than a full dynamic model.

  14. Incorporating remote sensing-based ET estimates into the Community Land Model version 4.5

    Directory of Open Access Journals (Sweden)

    D. Wang

    2017-07-01

    Full Text Available Land surface models bear substantial biases in simulating surface water and energy budgets despite the continuous development and improvement of model parameterizations. To reduce model biases, Parr et al. (2015 proposed a method incorporating satellite-based evapotranspiration (ET products into land surface models. Here we apply this bias correction method to the Community Land Model version 4.5 (CLM4.5 and test its performance over the conterminous US (CONUS. We first calibrate a relationship between the observational ET from the Global Land Evaporation Amsterdam Model (GLEAM product and the model ET from CLM4.5, and assume that this relationship holds beyond the calibration period. During the validation or application period, a simulation using the default CLM4.5 (CLM is conducted first, and its output is combined with the calibrated observational-vs.-model ET relationship to derive a corrected ET; an experiment (CLMET is then conducted in which the model-generated ET is overwritten with the corrected ET. Using the observations of ET, runoff, and soil moisture content as benchmarks, we demonstrate that CLMET greatly improves the hydrological simulations over most of the CONUS, and the improvement is stronger in the eastern CONUS than the western CONUS and is strongest over the Southeast CONUS. For any specific region, the degree of the improvement depends on whether the relationship between observational and model ET remains time-invariant (a fundamental hypothesis of the Parr et al. (2015 method and whether water is the limiting factor in places where ET is underestimated. While the bias correction method improves hydrological estimates without improving the physical parameterization of land surface models, results from this study do provide guidance for physically based model development effort.

  15. The Use of Artificial Neural Networks for Identifying Sustainable Biodiesel Feedstocks

    Directory of Open Access Journals (Sweden)

    Zoran D. Ristovski

    2013-07-01

    Full Text Available Over the past few decades, biodiesel produced from oilseed crops and animal fat is receiving much attention as a renewable and sustainable alternative for automobile engine fuels, and particularly petroleum diesel. However, current biodiesel production is heavily dependent on edible oil feedstocks which are unlikely to be sustainable in the longer term due to the rising food prices and the concerns about automobile engine durability. Therefore, there is an urgent need for researchers to identify and develop sustainable biodiesel feedstocks which overcome the disadvantages of current ones. On the other hand, artificial neural network (ANN modeling has been successfully used in recent years to gain new knowledge in various disciplines. The main goal of this article is to review recent literatures and assess the state of the art on the use of ANN as a modeling tool for future generation biodiesel feedstocks. Biodiesel feedstocks, production processes, chemical compositions, standards, physio-chemical properties and in-use performance are discussed. Limitations of current biodiesel feedstocks over future generation biodiesel feedstock have been identified. The application of ANN in modeling key biodiesel quality parameters and combustion performance in automobile engines is also discussed. This review has determined that ANN modeling has a high potential to contribute to the development of renewable energy systems by accelerating biodiesel research.

  16. Incorporation of mantle effects in lithospheric stress modeling: the Eurasian plate

    Science.gov (United States)

    Ruckstuhl, K.; Wortel, M. J. R.; Govers, R.; Meijer, P.

    2009-04-01

    The intraplate stress field is the result of forces acting on the lithosphere and as such contains valuable information on the dynamics of plate tectonics. Studies modeling the intraplate stress field have followed two different approaches, with the emphasis either on the lithosphere itself or the underlying convecting mantle. For most tectonic plates on earth one or both methods have been quiet successful in reproducing the large scale stress field. The Eurasian plate however has remained a challenge. A probable cause is that due to the complexity of the plate successful models require both an active mantle and well defined boundary forces. We therefore construct a model for the Eurasian plate in which we combine both modeling approaches by incorporating the effects of an active mantle in a model based on a lithospheric approach, where boundary forces are modeled explicitly. The assumption that the whole plate is in dynamical equilibrium allows for imposing a torque balance on the plate, which provides extra constraints on the forces that cannot be calculated a priori. Mantle interaction is modeled as a shear at the base of the plate obtained from global mantle flow models from literature. A first order approximation of the increased excess pressure of the anomalous ridge near the Iceland hotspot is incorporated. Results are evaluated by comparison with World Stress Map data. Direct incorporation of the sublithospheric stresses from mantle flow modeling in our force model is not possible, due to a discrepancy in the magnitude of the integrated mantle shear and lithospheric forces of around one order of magnitude, prohibiting balance of the torques. This magnitude discrepancy is a well known fundamental problem in geodynamics and we choose to close the gap between the two different approaches by scaling down the absolute magnitude of the sublithospheric stresses. Becker and O'Connell (G3,2,2001) showed that various mantle flow models show a considerable spread in

  17. Reliability modelling of redundant safety systems without automatic diagnostics incorporating common cause failures and process demand.

    Science.gov (United States)

    Alizadeh, Siamak; Sriramula, Srinivas

    2017-11-01

    Redundant safety systems are commonly used in the process industry to respond to hazardous events. In redundant systems composed of identical units, Common Cause Failures (CCFs) can significantly influence system performance with regards to reliability and safety. However, their impact has been overlooked due to the inherent complexity of modelling common cause induced failures. This article develops a reliability model for a redundant safety system using Markov analysis approach. The proposed model incorporates process demands in conjunction with CCF for the first time and evaluates their impacts on the reliability quantification of safety systems without automatic diagnostics. The reliability of the Markov model is quantified by considering the Probability of Failure on Demand (PFD) as a measure for low demand systems. The safety performance of the model is analysed using Hazardous Event Frequency (HEF) to evaluate the frequency of entering a hazardous state that will lead to an accident if the situation is not controlled. The utilisation of Markov model for a simple case study of a pressure protection system is demonstrated and it is shown that the proposed approach gives a sufficiently accurate result for all demand rates, durations, component failure rates and corresponding repair rates for low demand mode of operation. The Markov model proposed in this paper assumes the absence of automatic diagnostics, along with multiple stage repair strategy for CCFs and restoration of the system from hazardous state to the "as good as new" state. Copyright © 2017 ISA. Published by Elsevier Ltd. All rights reserved.

  18. Fuzzy Logic-Based Model That Incorporates Personality Traits for Heterogeneous Pedestrians

    Directory of Open Access Journals (Sweden)

    Zhuxin Xue

    2017-10-01

    Full Text Available Most models designed to simulate pedestrian dynamical behavior are based on the assumption that human decision-making can be described using precise values. This study proposes a new pedestrian model that incorporates fuzzy logic theory into a multi-agent system to address cognitive behavior that introduces uncertainty and imprecision during decision-making. We present a concept of decision preferences to represent the intrinsic control factors of decision-making. To realize the different decision preferences of heterogeneous pedestrians, the Five-Factor (OCEAN personality model is introduced to model the psychological characteristics of individuals. Then, a fuzzy logic-based approach is adopted for mapping the relationships between the personality traits and the decision preferences. Finally, we have developed an application using our model to simulate pedestrian dynamical behavior in several normal or non-panic scenarios, including a single-exit room, a hallway with obstacles, and a narrowing passage. The effectiveness of the proposed model is validated with a user study. The results show that the proposed model can generate more reasonable and heterogeneous behavior in the simulation and indicate that individual personality has a noticeable effect on pedestrian dynamical behavior.

  19. Incorporating vehicle mix in stimulus-response car-following models

    Directory of Open Access Journals (Sweden)

    Saidi Siuhi

    2016-06-01

    Full Text Available The objective of this paper is to incorporate vehicle mix in stimulus-response car-following models. Separate models were estimated for acceleration and deceleration responses to account for vehicle mix via both movement state and vehicle type. For each model, three sub-models were developed for different pairs of following vehicles including “automobile following automobile,” “automobile following truck,” and “truck following automobile.” The estimated model parameters were then validated against other data from a similar region and roadway. The results indicated that drivers' behaviors were significantly different among the different pairs of following vehicles. Also the magnitude of the estimated parameters depends on the type of vehicle being driven and/or followed. These results demonstrated the need to use separate models depending on movement state and vehicle type. The differences in parameter estimates confirmed in this paper highlight traffic safety and operational issues of mixed traffic operation on a single lane. The findings of this paper can assist transportation professionals to improve traffic simulation models used to evaluate the impact of different strategies on ameliorate safety and performance of highways. In addition, driver response time lag estimates can be used in roadway design to calculate important design parameters such as stopping sight distance on horizontal and vertical curves for both automobiles and trucks.

  20. A constitutive mechanical model for gas hydrate bearing sediments incorporating inelastic mechanisms

    KAUST Repository

    Sánchez, Marcelo

    2016-11-30

    Gas hydrate bearing sediments (HBS) are natural soils formed in permafrost and sub-marine settings where the temperature and pressure conditions are such that gas hydrates are stable. If these conditions shift from the hydrate stability zone, hydrates dissociate and move from the solid to the gas phase. Hydrate dissociation is accompanied by significant changes in sediment structure and strongly affects its mechanical behavior (e.g., sediment stiffenss, strength and dilatancy). The mechanical behavior of HBS is very complex and its modeling poses great challenges. This paper presents a new geomechanical model for hydrate bearing sediments. The model incorporates the concept of partition stress, plus a number of inelastic mechanisms proposed to capture the complex behavior of this type of soil. This constitutive model is especially well suited to simulate the behavior of HBS upon dissociation. The model was applied and validated against experimental data from triaxial and oedometric tests conducted on manufactured and natural specimens involving different hydrate saturation, hydrate morphology, and confinement conditions. Particular attention was paid to model the HBS behavior during hydrate dissociation under loading. The model performance was highly satisfactory in all the cases studied. It managed to properly capture the main features of HBS mechanical behavior and it also assisted to interpret the behavior of this type of sediment under different loading and hydrate conditions.

  1. Advanced Methods for Incorporating Solar Energy Technologies into Electric Sector Capacity-Expansion Models: Literature Review and Analysis

    Energy Technology Data Exchange (ETDEWEB)

    Sullivan, P.; Eurek, K.; Margolis, R.

    2014-07-01

    Because solar power is a rapidly growing component of the electricity system, robust representations of solar technologies should be included in capacity-expansion models. This is a challenge because modeling the electricity system--and, in particular, modeling solar integration within that system--is a complex endeavor. This report highlights the major challenges of incorporating solar technologies into capacity-expansion models and shows examples of how specific models address those challenges. These challenges include modeling non-dispatchable technologies, determining which solar technologies to model, choosing a spatial resolution, incorporating a solar resource assessment, and accounting for solar generation variability and uncertainty.

  2. Incorporating uncertainty of management costs in sensitivity analyses of matrix population models.

    Science.gov (United States)

    Salomon, Yacov; McCarthy, Michael A; Taylor, Peter; Wintle, Brendan A

    2013-02-01

    The importance of accounting for economic costs when making environmental-management decisions subject to resource constraints has been increasingly recognized in recent years. In contrast, uncertainty associated with such costs has often been ignored. We developed a method, on the basis of economic theory, that accounts for the uncertainty in population-management decisions. We considered the case where, rather than taking fixed values, model parameters are random variables that represent the situation when parameters are not precisely known. Hence, the outcome is not precisely known either. Instead of maximizing the expected outcome, we maximized the probability of obtaining an outcome above a threshold of acceptability. We derived explicit analytical expressions for the optimal allocation and its associated probability, as a function of the threshold of acceptability, where the model parameters were distributed according to normal and uniform distributions. To illustrate our approach we revisited a previous study that incorporated cost-efficiency analyses in management decisions that were based on perturbation analyses of matrix population models. Incorporating derivations from this study into our framework, we extended the model to address potential uncertainties. We then applied these results to 2 case studies: management of a Koala (Phascolarctos cinereus) population and conservation of an olive ridley sea turtle (Lepidochelys olivacea) population. For low aspirations, that is, when the threshold of acceptability is relatively low, the optimal strategy was obtained by diversifying the allocation of funds. Conversely, for high aspirations, the budget was directed toward management actions with the highest potential effect on the population. The exact optimal allocation was sensitive to the choice of uncertainty model. Our results highlight the importance of accounting for uncertainty when making decisions and suggest that more effort should be placed on

  3. Discontinuous Galerkin Time-Domain Modeling of Graphene Nano-Ribbon Incorporating the Spatial Dispersion Effects

    KAUST Repository

    Li, Ping

    2018-04-13

    It is well known that graphene demonstrates spatial dispersion properties, i.e., its conductivity is nonlocal and a function of spectral wave number (momentum operator) q. In this paper, to account for effects of spatial dispersion on transmission of high speed signals along graphene nano-ribbon (GNR) interconnects, a discontinuous Galerkin time-domain (DGTD) algorithm is proposed. The atomically-thick GNR is modeled using a nonlocal transparent surface impedance boundary condition (SIBC) incorporated into the DGTD scheme. Since the conductivity is a complicated function of q (and one cannot find an analytical Fourier transform pair between q and spatial differential operators), an exact time domain SIBC model cannot be derived. To overcome this problem, the conductivity is approximated by its Taylor series in spectral domain under low-q assumption. This approach permits expressing the time domain SIBC in the form of a second-order partial differential equation (PDE) in current density and electric field intensity. To permit easy incorporation of this PDE with the DGTD algorithm, three auxiliary variables, which degenerate the second-order (temporal and spatial) differential operators to first-order ones, are introduced. Regarding to the temporal dispersion effects, the auxiliary differential equation (ADE) method is utilized to eliminates the expensive temporal convolutions. To demonstrate the applicability of the proposed scheme, numerical results, which involve characterization of spatial dispersion effects on the transfer impedance matrix of GNR interconnects, are presented.

  4. Incorporating and Compensating Cerebrospinal Fluid in Surface-Based Forward Models of Magneto- and Electroencephalography.

    Directory of Open Access Journals (Sweden)

    Matti Stenroos

    Full Text Available MEG/EEG source imaging is usually done using a three-shell (3-S or a simpler head model. Such models omit cerebrospinal fluid (CSF that strongly affects the volume currents. We present a four-compartment (4-C boundary-element (BEM model that incorporates the CSF and is computationally efficient and straightforward to build using freely available software. We propose a way for compensating the omission of CSF by decreasing the skull conductivity of the 3-S model, and study the robustness of the 4-C and 3-S models to errors in skull conductivity. We generated dense boundary meshes using MRI datasets and automated SimNIBS pipeline. Then, we built a dense 4-C reference model using Galerkin BEM, and 4-C and 3-S test models using coarser meshes and both Galerkin and collocation BEMs. We compared field topographies of cortical sources, applying various skull conductivities and fitting conductivities that minimized the relative error in 4-C and 3-S models. When the CSF was left out from the EEG model, our compensated, unbiased approach improved the accuracy of the 3-S model considerably compared to the conventional approach, where CSF is neglected without any compensation (mean relative error 40%. The error due to the omission of CSF was of the same order in MEG and compensated EEG. EEG has, however, large overall error due to uncertain skull conductivity. Our results show that a realistic 4-C MEG/EEG model can be implemented using standard tools and basic BEM, without excessive workload or computational burden. If the CSF is omitted, compensated skull conductivity should be used in EEG.

  5. A MULTI-RESOLUTION FUSION MODEL INCORPORATING COLOR AND ELEVATION FOR SEMANTIC SEGMENTATION

    Directory of Open Access Journals (Sweden)

    W. Zhang

    2017-05-01

    Full Text Available In recent years, the developments for Fully Convolutional Networks (FCN have led to great improvements for semantic segmentation in various applications including fused remote sensing data. There is, however, a lack of an in-depth study inside FCN models which would lead to an understanding of the contribution of individual layers to specific classes and their sensitivity to different types of input data. In this paper, we address this problem and propose a fusion model incorporating infrared imagery and Digital Surface Models (DSM for semantic segmentation. The goal is to utilize heterogeneous data more accurately and effectively in a single model instead of to assemble multiple models. First, the contribution and sensitivity of layers concerning the given classes are quantified by means of their recall in FCN. The contribution of different modalities on the pixel-wise prediction is then analyzed based on visualization. Finally, an optimized scheme for the fusion of layers with color and elevation information into a single FCN model is derived based on the analysis. Experiments are performed on the ISPRS Vaihingen 2D Semantic Labeling dataset. Comprehensive evaluations demonstrate the potential of the proposed approach.

  6. Modelling and Simulation of a Manipulator with Stable Viscoelastic Grasping Incorporating Friction

    Directory of Open Access Journals (Sweden)

    A. Khurshid

    2016-12-01

    Full Text Available Design, dynamics and control of a humanoid robotic hand based on anthropological dimensions, with joint friction, is modelled, simulated and analysed in this paper by using computer aided design and multibody dynamic simulation. Combined joint friction model is incorporated in the joints. Experimental values of coefficient of friction of grease lubricated sliding contacts representative of manipulator joints are presented. Human fingers deform to the shape of the grasped object (enveloping grasp at the area of interaction. A mass-spring-damper model of the grasp is developed. The interaction of the viscoelastic gripper of the arm with objects is analysed by using Bond Graph modelling method. Simulations were conducted for several material parameters. These results of the simulation are then used to develop a prototype of the proposed gripper. Bond graph model is experimentally validated by using the prototype. The gripper is used to successfully transport soft and fragile objects. This paper provides information on optimisation of friction and its inclusion in both dynamic modelling and simulation to enhance mechanical efficiency.

  7. Developing a stochastic parameterization to incorporate plant trait variability into ecohydrologic modeling

    Science.gov (United States)

    Liu, S.; Ng, G. H. C.

    2017-12-01

    The global plant database has revealed that plant traits can vary more within a plant functional type (PFT) than among different PFTs, indicating that the current paradigm in ecohydrogical models of specifying fixed parameters based solely on plant functional type (PFT) could potentially bias simulations. Although some recent modeling studies have attempted to incorporate this observed plant trait variability, many failed to consider uncertainties due to sparse global observation, or they omitted spatial and/or temporal variability in the traits. Here we present a stochastic parameterization for prognostic vegetation simulations that are stochastic in time and space in order to represent plant trait plasticity - the process by which trait differences arise. We have developed the new PFT parameterization within the Community Land Model 4.5 (CLM 4.5) and tested the method for a desert shrubland watershed in the Mojave Desert, where fixed parameterizations cannot represent acclimation to desert conditions. Spatiotemporally correlated plant trait parameters were first generated based on TRY statistics and were then used to implement ensemble runs for the study area. The new PFT parameterization was then further conditioned on field measurements of soil moisture and remotely sensed observations of leaf-area-index to constrain uncertainties in the sparse global database. Our preliminary results show that incorporating data-conditioned, variable PFT parameterizations strongly affects simulated soil moisture and water fluxes, compared with default simulations. The results also provide new insights about correlations among plant trait parameters and between traits and environmental conditions in the desert shrubland watershed. Our proposed stochastic PFT parameterization method for ecohydrological models has great potential in advancing our understanding of how terrestrial ecosystems are predicted to adapt to variable environmental conditions.

  8. Incorporating Social System Dynamics into the Food-Energy-Water System Resilience-Sustainability Modeling Process

    Science.gov (United States)

    Givens, J.; Padowski, J.; Malek, K.; Guzman, C.; Boll, J.; Adam, J. C.; Witinok-Huber, R.

    2017-12-01

    In the face of climate change and multi-scalar governance objectives, achieving resilience of food-energy-water (FEW) systems requires interdisciplinary approaches. Through coordinated modeling and management efforts, we study "Innovations in the Food-Energy-Water Nexus (INFEWS)" through a case-study in the Columbia River Basin. Previous research on FEW system management and resilience includes some attention to social dynamics (e.g., economic, governance); however, more research is needed to better address social science perspectives. Decisions ultimately taken in this river basin would occur among stakeholders encompassing various institutional power structures including multiple U.S. states, tribal lands, and sovereign nations. The social science lens draws attention to the incompatibility between the engineering definition of resilience (i.e., return to equilibrium or a singular stable state) and the ecological and social system realities, more explicit in the ecological interpretation of resilience (i.e., the ability of a system to move into a different, possibly more resilient state). Social science perspectives include but are not limited to differing views on resilience as normative, system persistence versus transformation, and system boundary issues. To expand understanding of resilience and objectives for complex and dynamic systems, concepts related to inequality, heterogeneity, power, agency, trust, values, culture, history, conflict, and system feedbacks must be more tightly integrated into FEW research. We identify gaps in knowledge and data, and the value and complexity of incorporating social components and processes into systems models. We posit that socio-biophysical system resilience modeling would address important complex, dynamic social relationships, including non-linear dynamics of social interactions, to offer an improved understanding of sustainable management in FEW systems. Conceptual modeling that is presented in our study, represents

  9. A Loudness Model for Time-Varying Sounds Incorporating Binaural Inhibition

    Directory of Open Access Journals (Sweden)

    Brian C. J. Moore

    2016-12-01

    Full Text Available This article describes a model of loudness for time-varying sounds that incorporates the concept of binaural inhibition, namely, that the signal applied to one ear can reduce the internal response to a signal at the other ear. For each ear, the model includes the following: a filter to allow for the effects of transfer of sound through the outer and middle ear; a short-term spectral analysis with greater frequency resolution at low than at high frequencies; calculation of an excitation pattern, representing the magnitudes of the outputs of the auditory filters as a function of center frequency; application of a compressive nonlinearity to the output of each auditory filter; and smoothing over time of the resulting instantaneous specific loudness pattern using an averaging process resembling an automatic gain control. The resulting short-term specific loudness patterns are used to calculate broadly tuned binaural inhibition functions, the amount of inhibition depending on the relative short-term specific loudness at the two ears. The inhibited specific loudness patterns are summed across frequency to give an estimate of the short-term loudness for each ear. The overall short-term loudness is calculated as the sum of the short-term loudness values for the two ears. The long-term loudness for each ear is calculated by smoothing the short-term loudness for that ear, again by a process resembling automatic gain control, and the overall loudness impression is obtained by summing the long-term loudness across ears. The predictions of the model are more accurate than those of an earlier model that did not incorporate binaural inhibition.

  10. A model to incorporate organ deformation in the evaluation of dose/volume relationship

    International Nuclear Information System (INIS)

    Yan, D.; Jaffray, D.; Wong, J.; Brabbins, D.; Martinez, A. A.

    1997-01-01

    Purpose: Measurements of internal organ motion have demonstrated that daily organ deformation exists during the course of radiation treatment. However, a model to evaluate the resultant dose delivered to a daily deformed organ remains a difficult challenge. Current methods which model such organ deformation as rigid body motion in the dose calculation for treatment planning evaluation are incorrect and misleading. In this study, a new model for treatment planning evaluation is introduced which incorporates patient specific information of daily organ deformation and setup variation. The model was also used to retrospectively analyze the actual treatment data measured using daily CT scans for 5 patients with prostate treatment. Methods and Materials: The model assumes that for each patient, the organ of interest can be measured during the first few treatment days. First, the volume of each organ is delineated from each of the daily measurements and cumulated in a 3D bit-map. A tissue occupancy distribution is then constructed with the 50% isodensity representing the mean, or effective, organ volume. During the course of treatment, each voxel in the effective organ volume is assumed to move inside a local 3D neighborhood with a specific distribution function. The neighborhood and the distribution function are deduced from the positions and shapes of the organ in the first few measurements using the biomechanics model of viscoelastic body. For each voxel, the local distribution function is then convolved with the spatial dose distribution. The latter includes also the variation in dose due to daily setup error. As a result, the cumulative dose to the voxel incorporates the effects of daily setup variation and organ deformation. A ''variation adjusted'' dose volume histogram, aDVH, for the effective organ volume can then be constructed for the purpose of treatment evaluation and optimization. Up to 20 daily CT scans and daily portal images for 5 patients with prostate

  11. Impact of Various Biofuel Feedstock Production Scenarios on Water Quality in the Upper Mississippi River Basin

    Science.gov (United States)

    Wu, M.; Demissie, Y.; Yan, E.

    2010-12-01

    The impact of increased biofuel feedstock production on regional water quality was examined. This study focused on the Upper Mississippi River Basin, from which a majority of U.S. biofuel is currently produced. The production of biofuel from both conventional feedstock and cellulosic feedstock will potentially increase in the near future. Historically, this water basin generates the largest nitrogen loading to the waterway in the United States and is often cited as a main contributor to the anoxic zone in the Gulf of Mexico. To obtain a quantitative and spatial estimate of nutrient burdens at the river basin, a SWAT (Soil and Water Assessment Tool) model application was developed. The model was equipped with an updated nutrient cycle feature and modified model parameters to represent current crop and perennial grass yield as a result of advancements in breeding and biotechnology. Various biofuel feedstock production scenarios were developed to assess the potential environmental implications of increased biofuel production through corn, agriculture residue, and perennial cellulosic feedstock (such as Switchgrass). Major factors were analyzed, including land use changes, feedstock types, fertilizer inputs, soil property, and yield. This tool can be used to identify specific regional factors affecting water quality and examine options to meet the requirement for environmental sustainability, thereby mitigating undesirable environmental consequences while strengthening energy security.

  12. Simulation of Forest Carbon Fluxes Using Model Incorporation and Data Assimilation

    Directory of Open Access Journals (Sweden)

    Min Yan

    2016-07-01

    Full Text Available This study improved simulation of forest carbon fluxes in the Changbai Mountains with a process-based model (Biome-BGC using incorporation and data assimilation. Firstly, the original remote sensing-based MODIS MOD_17 GPP (MOD_17 model was optimized using refined input data and biome-specific parameters. The key ecophysiological parameters of the Biome-BGC model were determined through the Extended Fourier Amplitude Sensitivity Test (EFAST sensitivity analysis. Then the optimized MOD_17 model was used to calibrate the Biome-BGC model by adjusting the sensitive ecophysiological parameters. Once the best match was found for the 10 selected forest plots for the 8-day GPP estimates from the optimized MOD_17 and from the Biome-BGC, the values of sensitive ecophysiological parameters were determined. The calibrated Biome-BGC model agreed better with the eddy covariance (EC measurements (R2 = 0.87, RMSE = 1.583 gC·m−2·d−1 than the original model did (R2 = 0.72, RMSE = 2.419 gC·m−2·d−1. To provide a best estimate of the true state of the model, the Ensemble Kalman Filter (EnKF was used to assimilate five years (of eight-day periods between 2003 and 2007 of Global LAnd Surface Satellite (GLASS LAI products into the calibrated Biome-BGC model. The results indicated that LAI simulated through the assimilated Biome-BGC agreed well with GLASS LAI. GPP performances obtained from the assimilated Biome-BGC were further improved and verified by EC measurements at the Changbai Mountains forest flux site (R2 = 0.92, RMSE = 1.261 gC·m−2·d−1.

  13. Effect of Control-released Basic Fibroblast Growth Factor Incorporated in β-Tricalcium Phosphate for Murine Cranial Model

    Directory of Open Access Journals (Sweden)

    Azusa Shimizu, MD

    2014-03-01

    Conclusions: These findings suggest that control-released bFGF incorporated in β-TCP can accelerate bone regeneration in the murine cranial defect model and may be promising for the clinical treatment of cranial defects.

  14. Incorporating plant fossil data into species distribution models is not straightforward: Pitfalls and possible solutions

    Science.gov (United States)

    Moreno-Amat, Elena; Rubiales, Juan Manuel; Morales-Molino, César; García-Amorena, Ignacio

    2017-08-01

    The increasing development of species distribution models (SDMs) using palaeodata has created new prospects to address questions of evolution, ecology and biogeography from wider perspectives. Palaeobotanical data provide information on the past distribution of taxa at a given time and place and its incorporation on modelling has contributed to advancing the SDM field. This has allowed, for example, to calibrate models under past climate conditions or to validate projected models calibrated on current species distributions. However, these data also bear certain shortcomings when used in SDMs that may hinder the resulting ecological outcomes and eventually lead to misleading conclusions. Palaeodata may not be equivalent to present data, but instead frequently exhibit limitations and biases regarding species representation, taxonomy and chronological control, and their inclusion in SDMs should be carefully assessed. The limitations of palaeobotanical data applied to SDM studies are infrequently discussed and often neglected in the modelling literature; thus, we argue for the more careful selection and control of these data. We encourage authors to use palaeobotanical data in their SDMs studies and for doing so, we propose some recommendations to improve the robustness, reliability and significance of palaeo-SDM analyses.

  15. Energy system investment model incorporating heat pumps with thermal storage in buildings and buffer tanks

    International Nuclear Information System (INIS)

    Hedegaard, Karsten; Balyk, Olexandr

    2013-01-01

    Individual compression heat pumps constitute a potentially valuable resource in supporting wind power integration due to their economic competitiveness and possibilities for flexible operation. When analysing the system benefits of flexible heat pump operation, effects on investments should be taken into account. In this study, we present a model that facilitates analysing individual heat pumps and complementing heat storages in integration with the energy system, while optimising both investments and operation. The model incorporates thermal building dynamics and covers various heat storage options: passive heat storage in the building structure via radiator heating, active heat storage in concrete floors via floor heating, and use of thermal storage tanks for space heating and hot water. It is shown that the model is well qualified for analysing possibilities and system benefits of operating heat pumps flexibly. This includes prioritising heat pump operation for hours with low marginal electricity production costs, and peak load shaving resulting in a reduced need for peak and reserve capacity investments. - Highlights: • Model optimising heat pumps and heat storages in integration with the energy system. • Optimisation of both energy system investments and operation. • Heat storage in building structure and thermal storage tanks included. • Model well qualified for analysing system benefits of flexible heat pump operation. • Covers peak load shaving and operation prioritised for low electricity prices

  16. A General Framework for Incorporating Stochastic Recovery in Structural Models of Credit Risk

    Directory of Open Access Journals (Sweden)

    Albert Cohen

    2017-12-01

    Full Text Available In this work, we introduce a general framework for incorporating stochastic recovery into structural models. The framework extends the approach to recovery modeling developed in Cohen and Costanzino (2015, 2017 and provides for a systematic way to include different recovery processes into a structural credit model. The key observation is a connection between the partial information gap between firm manager and the market that is captured via a distortion of the probability of default. This last feature is computed by what is essentially a Girsanov transformation and reflects untangling of the recovery process from the default probability. Our framework can be thought of as an extension of Ishizaka and Takaoka (2003 and, in the same spirit of their work, we provide several examples of the framework including bounded recovery and a jump-to-zero model. One of the nice features of our framework is that, given prices from any one-factor structural model, we provide a systematic way to compute corresponding prices with stochastic recovery. The framework also provides a way to analyze correlation between Probability of Default (PD and Loss Given Default (LGD, and term structure of recovery rates.

  17. a Maximum Entropy Model of the Bearded Capuchin Monkey Habitat Incorporating Topography and Spectral Unmixing Analysis

    Science.gov (United States)

    Howard, A. M.; Bernardes, S.; Nibbelink, N.; Biondi, L.; Presotto, A.; Fragaszy, D. M.; Madden, M.

    2012-07-01

    Movement patterns of bearded capuchin monkeys (Cebus (Sapajus) libidinosus) in northeastern Brazil are likely impacted by environmental features such as elevation, vegetation density, or vegetation type. Habitat preferences of these monkeys provide insights regarding the impact of environmental features on species ecology and the degree to which they incorporate these features in movement decisions. In order to evaluate environmental features influencing movement patterns and predict areas suitable for movement, we employed a maximum entropy modelling approach, using observation points along capuchin monkey daily routes as species presence points. We combined these presence points with spatial data on important environmental features from remotely sensed data on land cover and topography. A spectral mixing analysis procedure was used to generate fraction images that represent green vegetation, shade and soil of the study area. A Landsat Thematic Mapper scene of the area of study was geometrically and atmospherically corrected and used as input in a Minimum Noise Fraction (MNF) procedure and a linear spectral unmixing approach was used to generate the fraction images. These fraction images and elevation were the environmental layer inputs for our logistic MaxEnt model of capuchin movement. Our models' predictive power (test AUC) was 0.775. Areas of high elevation (>450 m) showed low probabilities of presence, and percent green vegetation was the greatest overall contributor to model AUC. This work has implications for predicting daily movement patterns of capuchins in our field site, as suitability values from our model may relate to habitat preference and facility of movement.

  18. Incorporating social groups' responses in a descriptive model for second- and higher-order impact identification

    International Nuclear Information System (INIS)

    Sutheerawatthana, Pitch; Minato, Takayuki

    2010-01-01

    The response of a social group is a missing element in the formal impact assessment model. Previous discussion of the involvement of social groups in an intervention has mainly focused on the formation of the intervention. This article discusses the involvement of social groups in a different way. A descriptive model is proposed by incorporating a social group's response into the concept of second- and higher-order effects. The model is developed based on a cause-effect relationship through the observation of phenomena in case studies. The model clarifies the process by which social groups interact with a lower-order effect and then generate a higher-order effect in an iterative manner. This study classifies social groups' responses into three forms-opposing, modifying, and advantage-taking action-and places them in six pathways. The model is expected to be used as an analytical tool for investigating and identifying impacts in the planning stage and as a framework for monitoring social groups' responses during the implementation stage of a policy, plan, program, or project (PPPPs).

  19. How non-conventional feedstocks will affect aromatics technologies

    Energy Technology Data Exchange (ETDEWEB)

    Koehler, E. [Clariant Produkte (Deutschland) GmbH, Muenchen (Germany)

    2013-11-01

    The abundance of non-conventional feedstocks such as coal and shale gas has begun to affect the availability of traditional base chemicals such as propylene and BTX aromatics. Although this trend is primarily fueled by the fast growing shale gas economy in the US and the abundance of coal in China, it will cause the global supply and demand situation to equilibrate across the regions. Lower demand for gasoline and consequently less aromatics rich reformate from refineries will further tighten the aromatics markets that are expected to grow at healthy rates, however. Refiners can benefit from this trend by abandoning their traditional fuel-oriented business model and becoming producers of petrochemical intermediates, with special focus on paraxylene (PX). Cheap gas from coal (via gasification) or shale reserves is an advantaged feedstock that offers a great platform to make aromatics in a cost-competitive manner, especially in regions where naphtha is in short supply. Gas condensates (LPG and naphtha) are good feedstocks for paraffin aromatization, and methanol from coal or (shale) gas can be directly converted to BTX aromatics (MTA) or alkylated with benzene or toluene to make paraxylene. Most of today's technologies for the production and upgrading of BTX aromatics and their derivatives make use of the unique properties of zeolites. (orig.)

  20. Petroacoustic Modelling of Heterolithic Sandstone Reservoirs: A Novel Approach to Gassmann Modelling Incorporating Sedimentological Constraints and NMR Porosity data

    Science.gov (United States)

    Matthews, S.; Lovell, M.; Davies, S. J.; Pritchard, T.; Sirju, C.; Abdelkarim, A.

    2012-12-01

    Heterolithic or 'shaly' sandstone reservoirs constitute a significant proportion of hydrocarbon resources. Petroacoustic models (a combination of petrophysics and rock physics) enhance the ability to extract reservoir properties from seismic data, providing a connection between seismic and fine-scale rock properties. By incorporating sedimentological observations these models can be better constrained and improved. Petroacoustic modelling is complicated by the unpredictable effects of clay minerals and clay-sized particles on geophysical properties. Such effects are responsible for erroneous results when models developed for "clean" reservoirs - such as Gassmann's equation (Gassmann, 1951) - are applied to heterolithic sandstone reservoirs. Gassmann's equation is arguably the most popular petroacoustic modelling technique in the hydrocarbon industry and is used to model elastic effects of changing reservoir fluid saturations. Successful implementation of Gassmann's equation requires well-constrained drained rock frame properties, which in heterolithic sandstones are heavily influenced by reservoir sedimentology, particularly clay distribution. The prevalent approach to categorising clay distribution is based on the Thomas - Stieber model (Thomas & Stieber, 1975), this approach is inconsistent with current understanding of 'shaly sand' sedimentology and omits properties such as sorting and grain size. The novel approach presented here demonstrates that characterising reservoir sedimentology constitutes an important modelling phase. As well as incorporating sedimentological constraints, this novel approach also aims to improve drained frame moduli estimates through more careful consideration of Gassmann's model assumptions and limitations. A key assumption of Gassmann's equation is a pore space in total communication with movable fluids. This assumption is often violated by conventional applications in heterolithic sandstone reservoirs where effective porosity, which

  1. Incorporating teleconnection information into reservoir operating policies using Stochastic Dynamic Programming and a Hidden Markov Model

    Science.gov (United States)

    Turner, Sean; Galelli, Stefano; Wilcox, Karen

    2015-04-01

    Water reservoir systems are often affected by recurring large-scale ocean-atmospheric anomalies, known as teleconnections, that cause prolonged periods of climatological drought. Accurate forecasts of these events -- at lead times in the order of weeks and months -- may enable reservoir operators to take more effective release decisions to improve the performance of their systems. In practice this might mean a more reliable water supply system, a more profitable hydropower plant or a more sustainable environmental release policy. To this end, climate indices, which represent the oscillation of the ocean-atmospheric system, might be gainfully employed within reservoir operating models that adapt the reservoir operation as a function of the climate condition. This study develops a Stochastic Dynamic Programming (SDP) approach that can incorporate climate indices using a Hidden Markov Model. The model simulates the climatic regime as a hidden state following a Markov chain, with the state transitions driven by variation in climatic indices, such as the Southern Oscillation Index. Time series analysis of recorded streamflow data reveals the parameters of separate autoregressive models that describe the inflow to the reservoir under three representative climate states ("normal", "wet", "dry"). These models then define inflow transition probabilities for use in a classic SDP approach. The key advantage of the Hidden Markov Model is that it allows conditioning the operating policy not only on the reservoir storage and the antecedent inflow, but also on the climate condition, thus potentially allowing adaptability to a broader range of climate conditions. In practice, the reservoir operator would effect a water release tailored to a specific climate state based on available teleconnection data and forecasts. The approach is demonstrated on the operation of a realistic, stylised water reservoir with carry-over capacity in South-East Australia. Here teleconnections relating

  2. A generalized linear-quadratic model incorporating reciprocal time pattern of radiation damage repair

    International Nuclear Information System (INIS)

    Huang, Zhibin; Mayr, Nina A.; Lo, Simon S.; Wang, Jian Z.; Jia Guang; Yuh, William T. C.; Johnke, Roberta

    2012-01-01

    Purpose: It has been conventionally assumed that the repair rate for sublethal damage (SLD) remains constant during the entire radiation course. However, increasing evidence from animal studies suggest that this may not the case. Rather, it appears that the repair rate for radiation-induced SLD slows down with increasing time. Such a slowdown in repair would suggest that the exponential repair pattern would not necessarily accurately predict repair process. As a result, the purpose of this study was to investigate a new generalized linear-quadratic (LQ) model incorporating a repair pattern with reciprocal time. The new formulas were tested with published experimental data. Methods: The LQ model has been widely used in radiation therapy, and the parameter G in the surviving fraction represents the repair process of sublethal damage with T r as the repair half-time. When a reciprocal pattern of repair process was adopted, a closed form of G was derived analytically for arbitrary radiation schemes. The published animal data adopted to test the reciprocal formulas. Results: A generalized LQ model to describe the repair process in a reciprocal pattern was obtained. Subsequently, formulas for special cases were derived from this general form. The reciprocal model showed a better fit to the animal data than the exponential model, particularly for the ED50 data (reduced χ 2 min of 2.0 vs 4.3, p = 0.11 vs 0.006), with the following gLQ parameters: α/β = 2.6-4.8 Gy, T r = 3.2-3.9 h for rat feet skin, and α/β = 0.9 Gy, T r = 1.1 h for rat spinal cord. Conclusions: These results of repair process following a reciprocal time suggest that the generalized LQ model incorporating the reciprocal time of sublethal damage repair shows a better fit than the exponential repair model. These formulas can be used to analyze the experimental and clinical data, where a slowing-down repair process appears during the course of radiation therapy.

  3. A generalized linear-quadratic model incorporating reciprocal time pattern of radiation damage repair.

    Science.gov (United States)

    Huang, Zhibin; Mayr, Nina A; Lo, Simon S; Wang, Jian Z; Jia, Guang; Yuh, William T C; Johnke, Roberta

    2012-01-01

    It has been conventionally assumed that the repair rate for sublethal damage (SLD) remains constant during the entire radiation course. However, increasing evidence from animal studies suggest that this may not the case. Rather, it appears that the repair rate for radiation-induced SLD slows down with increasing time. Such a slowdown in repair would suggest that the exponential repair pattern would not necessarily accurately predict repair process. As a result, the purpose of this study was to investigate a new generalized linear-quadratic (LQ) model incorporating a repair pattern with reciprocal time. The new formulas were tested with published experimental data. The LQ model has been widely used in radiation therapy, and the parameter G in the surviving fraction represents the repair process of sublethal damage with T(r) as the repair half-time. When a reciprocal pattern of repair process was adopted, a closed form of G was derived analytically for arbitrary radiation schemes. The published animal data adopted to test the reciprocal formulas. A generalized LQ model to describe the repair process in a reciprocal pattern was obtained. Subsequently, formulas for special cases were derived from this general form. The reciprocal model showed a better fit to the animal data than the exponential model, particularly for the ED50 data (reduced χ(2) (min) of 2.0 vs 4.3, p = 0.11 vs 0.006), with the following gLQ parameters: α/β = 2.6-4.8 Gy, T(r) = 3.2-3.9 h for rat feet skin, and α/β = 0.9 Gy, T(r) = 1.1 h for rat spinal cord. These results of repair process following a reciprocal time suggest that the generalized LQ model incorporating the reciprocal time of sublethal damage repair shows a better fit than the exponential repair model. These formulas can be used to analyze the experimental and clinical data, where a slowing-down repair process appears during the course of radiation therapy.

  4. Biofuel Feedstock Assessment for Selected Countries

    Energy Technology Data Exchange (ETDEWEB)

    Kline, K.L.; Oladosu, G.A.; Wolfe, A.K.; Perlack, R.D.; Dale, V.H.

    2008-02-18

    Findings from biofuel feedstock production assessments and projections of future supply are presented and discussed. The report aims to improve capabilities to assess the degree to which imported biofuel could contribute to meeting future U.S. targets to reduce dependence on imported oil. The study scope was focused to meet time and resource requirements. A screening process identified Argentina, Brazil, Canada, China, Colombia, India, Mexico, and the Caribbean Basin Initiative (CBI) region for initial analysis, given their likely role in future feedstock supply relevant to U.S. markets. Supply curves for selected feedstocks in these countries are projected for 2012, 2017 and 2027. The supply functions, along with calculations to reflect estimated supplies available for export and/or biofuel production, were provided to DOE for use in a broader energy market allocation study. Potential cellulosic supplies from crop and forestry residues and perennials were also estimated for 2017 and 2027. The analysis identified capacity to potentially double or triple feedstock production by 2017 in some cases. A majority of supply growth is derived from increasing the area cultivated (especially sugarcane in Brazil). This is supplemented by improving yields and farming practices. Most future supplies of corn and wheat are projected to be allocated to food and feed. Larger shares of future supplies of sugarcane, soybean and palm oil production will be available for export or biofuel. National policies are catalyzing investments in biofuel industries to meet targets for fuel blending that generally fall in the 5-10% range. Social and environmental concerns associated with rapid expansion of feedstock production are considered. If the 2017 projected feedstock supply calculated as ‘available’ for export or biofuel were converted to fuel, it would represent the equivalent of about 38 billion gallons of gasoline. Sugarcane and bagasse dominate the available supply, representing 64

  5. Personalized Prognostic Prediction Models for Breast Cancer Recurrence and Survival Incorporating Multidimensional Data.

    Science.gov (United States)

    Wu, Xifeng; Ye, Yuanqing; Barcenas, Carlos H; Chow, Wong-Ho; Meng, Qing H; Chavez-MacGregor, Mariana; Hildebrandt, Michelle A T; Zhao, Hua; Gu, Xiangjun; Deng, Yang; Wagar, Elizabeth; Esteva, Francisco J; Tripathy, Debu; Hortobagyi, Gabriel N

    2017-07-01

    In this study, we developed integrative, personalized prognostic models for breast cancer recurrence and overall survival (OS) that consider receptor subtypes, epidemiological data, quality of life (QoL), and treatment. A total of 15 314 women with stage I to III invasive primary breast cancer treated at The University of Texas MD Anderson Cancer Center between 1997 and 2012 were used to generate prognostic models by Cox regression analysis in a two-stage study. Model performance was assessed by calculating the area under the curve (AUC) and calibration analysis and compared with Nottingham Prognostic Index (NPI) and PREDICT. Host characteristics were assessed for 10 809 women as the discovery population (median follow-up = 6.09 years, 1144 recurrence and 1627 deaths) and 4505 women as the validation population (median follow-up = 7.95 years, 684 recurrence and 1095 deaths). In addition to the known clinical/pathological variables, the model for recurrence included alcohol consumption while the model for OS included smoking status and physical component summary score. The AUCs for recurrence and OS were 0.813 and 0.810 in the discovery and 0.807 and 0.803 in the validation, respectively, compared with AUCs of 0.761 and 0.753 in discovery and 0.777 and 0.751 in validation for NPI. Our model further showed better calibration compared with PREDICT. We also developed race-specific and receptor subtype-specific models with comparable AUCs. Racial disparity was evident in the distributions of many risk factors and clinical presentation of the disease. Our integrative prognostic models for breast cancer exhibit high discriminatory accuracy and excellent calibration and are the first to incorporate receptor subtype and epidemiological and QoL data. © The Author 2017. Published by Oxford University Press. All rights reserved. For Permissions, please e-mail: journals.permissions@oup.com.

  6. A neural population model incorporating dopaminergic neurotransmission during complex voluntary behaviors.

    Directory of Open Access Journals (Sweden)

    Stefan Fürtinger

    2014-11-01

    Full Text Available Assessing brain activity during complex voluntary motor behaviors that require the recruitment of multiple neural sites is a field of active research. Our current knowledge is primarily based on human brain imaging studies that have clear limitations in terms of temporal and spatial resolution. We developed a physiologically informed non-linear multi-compartment stochastic neural model to simulate functional brain activity coupled with neurotransmitter release during complex voluntary behavior, such as speech production. Due to its state-dependent modulation of neural firing, dopaminergic neurotransmission plays a key role in the organization of functional brain circuits controlling speech and language and thus has been incorporated in our neural population model. A rigorous mathematical proof establishing existence and uniqueness of solutions to the proposed model as well as a computationally efficient strategy to numerically approximate these solutions are presented. Simulated brain activity during the resting state and sentence production was analyzed using functional network connectivity, and graph theoretical techniques were employed to highlight differences between the two conditions. We demonstrate that our model successfully reproduces characteristic changes seen in empirical data between the resting state and speech production, and dopaminergic neurotransmission evokes pronounced changes in modeled functional connectivity by acting on the underlying biological stochastic neural model. Specifically, model and data networks in both speech and rest conditions share task-specific network features: both the simulated and empirical functional connectivity networks show an increase in nodal influence and segregation in speech over the resting state. These commonalities confirm that dopamine is a key neuromodulator of the functional connectome of speech control. Based on reproducible characteristic aspects of empirical data, we suggest a number

  7. Incorporation of caffeine into a quantitative model of fatigue and sleep.

    Science.gov (United States)

    Puckeridge, M; Fulcher, B D; Phillips, A J K; Robinson, P A

    2011-03-21

    A recent physiologically based model of human sleep is extended to incorporate the effects of caffeine on sleep-wake timing and fatigue. The model includes the sleep-active neurons of the hypothalamic ventrolateral preoptic area (VLPO), the wake-active monoaminergic brainstem populations (MA), their interactions with cholinergic/orexinergic (ACh/Orx) input to MA, and circadian and homeostatic drives. We model two effects of caffeine on the brain due to competitive antagonism of adenosine (Ad): (i) a reduction in the homeostatic drive and (ii) an increase in cholinergic activity. By comparing the model output to experimental data, constraints are determined on the parameters that describe the action of caffeine on the brain. In accord with experiment, the ranges of these parameters imply significant variability in caffeine sensitivity between individuals, with caffeine's effectiveness in reducing fatigue being highly dependent on an individual's tolerance, and past caffeine and sleep history. Although there are wide individual differences in caffeine sensitivity and thus in parameter values, once the model is calibrated for an individual it can be used to make quantitative predictions for that individual. A number of applications of the model are examined, using exemplar parameter values, including: (i) quantitative estimation of the sleep loss and the delay to sleep onset after taking caffeine for various doses and times; (ii) an analysis of the system's stable states showing that the wake state during sleep deprivation is stabilized after taking caffeine; and (iii) comparing model output successfully to experimental values of subjective fatigue reported in a total sleep deprivation study examining the reduction of fatigue with caffeine. This model provides a framework for quantitatively assessing optimal strategies for using caffeine, on an individual basis, to maintain performance during sleep deprivation. Copyright © 2011 Elsevier Ltd. All rights reserved.

  8. The impact of incorporating molecular evolutionary model into predictions of phylogenetic signal and noise

    Directory of Open Access Journals (Sweden)

    Zhuo eSu

    2014-04-01

    Full Text Available Phylogenetic inference can be improved by the development and use of better models for inference given the data available, or by gathering more appropriate data given the potential inferences to be made. Numerous studies have demonstrated the crucial importance of selecting a best-fit model to conducting accurate phylogenetic inference given a data set, explicitly revealing how model choice affects the results of phylogenetic inferences. However, the importance of specifying a correct model of evolution for predictions of the best data to be gathered has never been examined. Here, we extend analyses of phylogenetic signal and noise that predict the potential to resolve nodes in a phylogeny to incorporate all time-reversible Markov models of nucleotide substitution. Extending previous results on the canonical four-taxon tree, our theory yields an analytical method that uses estimates of the rates of evolution and the model of molecular evolution to predict the distribution of signal, noise, and polytomy. We applied our methods to a study of 29 taxa of the yeast genus Candida and allied members to predict the power of five markers, COX2, ACT1, RPB1, RPB2, and D1/D2 LSU, to resolve a poorly supported backbone node corresponding to a clade of haploid Candida species, as well as nineteen other nodes that are reasonably short and at least moderately deep in the consensus tree. The use of simple, unrealistic models that did not take into account transition/transversion rate differences led to some discrepancies in predictions, but overall our results demonstrate that predictions of signal and noise in phylogenetics are fairly robust to model specification.

  9. High quality transportation fuels from renewable feedstock

    Energy Technology Data Exchange (ETDEWEB)

    Lindfors, Lars Peter

    2010-09-15

    Hydrotreating of vegetable oils is novel process for producing high quality renewable diesel. Hydrotreated vegetable oils (HVO) are paraffinic hydrocarbons. They are free of aromatics, have high cetane numbers and reduce emissions. HVO can be used as component or as such. HVO processes can also be modified to produce jet fuel. GHG savings by HVO use are significant compared to fossil fuels. HVO is already in commercial production. Neste Oil is producing its NExBTL diesel in two plants. Production of renewable fuels will be limited by availability of sustainable feedstock. Therefore R and D efforts are made to expand feedstock base further.

  10. Engineering cyanobacteria as photosynthetic feedstock factories.

    Science.gov (United States)

    Hays, Stephanie G; Ducat, Daniel C

    2015-03-01

    Carbohydrate feedstocks are at the root of bioindustrial production and are needed in greater quantities than ever due to increased prioritization of renewable fuels with reduced carbon footprints. Cyanobacteria possess a number of features that make them well suited as an alternative feedstock crop in comparison to traditional terrestrial plant species. Recent advances in genetic engineering, as well as promising preliminary investigations of cyanobacteria in a number of distinct production regimes have illustrated the potential of these aquatic phototrophs as biosynthetic chassis. Further improvements in strain productivities and design, along with enhanced understanding of photosynthetic metabolism in cyanobacteria may pave the way to translate cyanobacterial theoretical potential into realized application.

  11. Incorporating hydraulic/hydromorphologic properties and their stage dependency into hydrologic compartmental models

    Science.gov (United States)

    Gustafsson, A.; Wörman, A.

    2009-04-01

    According to recent studies, the volumetric error of the predicted size of the spring flood in Sweden can be as large as 20%. A significant part of this error originates from simplifications in the spatial and hydrodynamic description of watercourse networks, as well as statistical problems to give proper weight to extreme flows. Possible ways to improve current hydrological modelling practises is by making models more adapted to varying flow conditions as well as by increasing the coupling between model parameters and physical catchment characteristics. This study formulates a methodology based in hydrodynamical/hydraulic theory to investigate how river network characteristics vary with flow stage and how to transfer this information to compartmental hydrologic models such as the HBV/HYPE models. This is particularly important during extreme flows when a significant portion of the water flows outside the normal stream channels. The aim is to combine knowledge about the hydrodynamics and hydro-morphology of watercourse networks to improve the predictions of peak flows. HYPE is a semi-distributed conceptual compartmental hydrological model which is currently being developed at the SMHI as a successor to the HBV model. The model (HYPE) is thought to be better adapted to varying flow conditions by using the dynamical response functions derived by the methodology described here. The distribution of residence times within the watercourse network - and how these depend on flow stage is analysed. This information is then incorporated into the response functions of the HYPE model, i.e. the compartmental model receives a dynamic transformation function relating river discharge to storativity within the sub-catchment. This response function hence reflects the topologic and hydromorphologic characteristics of the watercourse network as well as flow stage. Seven subcatchments in Rönne River basin (1900 km2) are studied to show how this approach can improve the prediction of

  12. Incorporation of defects into the central atoms model of a metallic glass

    International Nuclear Information System (INIS)

    Lass, Eric A.; Zhu Aiwu; Shiflet, G.J.; Joseph Poon, S.

    2011-01-01

    The central atoms model (CAM) of a metallic glass is extended to incorporate thermodynamically stable defects, similar to vacancies in a crystalline solid, within the amorphous structure. A bond deficiency (BD), which is the proposed defect present in all metallic glasses, is introduced into the CAM equations. Like vacancies in a crystalline solid, BDs are thermodynamically stable entities because of the increase in entropy associated with their creation, and there is an equilibrium concentration present in the glassy phase. When applied to Cu-Zr and Ni-Zr binary metallic glasses, the concentration of thermally induced BDs surrounding Zr atoms reaches a relatively constant value at the glass transition temperature, regardless of composition within a given glass system. Using this 'critical' defect concentration, the predicted temperatures at which the glass transition is expected to occur are in good agreement with the experimentally determined glass transition temperatures for both alloy systems.

  13. A Microdosimetric-Kinetic Model of Cell Killing by Irradiation from Permanently Incorporated Radionuclides.

    Science.gov (United States)

    Hawkins, Roland B

    2018-01-01

    An expression for the surviving fraction of a replicating population of cells exposed to permanently incorporated radionuclide is derived from the microdosimetric-kinetic model. It includes dependency on total implant dose, linear energy transfer (LET), decay rate of the radionuclide, the repair rate of potentially lethal lesions in DNA and the volume doubling time of the target population. This is used to obtain an expression for the biologically effective dose ( BED α / β ) based on the minimum survival achieved by the implant that is equivalent to, and can be compared and combined with, the BED α / β calculated for a fractionated course of radiation treatment. Approximate relationships are presented that are useful in the calculation of BED α / β for alpha- or beta-emitting radionuclides with half-life significantly greater than, or nearly equal to, the approximately 1-h repair half-life of radiation-induced potentially lethal lesions.

  14. Upgrading of petroleum oil feedstocks using alkali metals and hydrocarbons

    Science.gov (United States)

    Gordon, John Howard

    2014-09-09

    A method of upgrading an oil feedstock by removing heteroatoms and/or one or more heavy metals from the oil feedstock composition. This method reacts the oil feedstock with an alkali metal and an upgradant hydrocarbon. The alkali metal reacts with a portion of the heteroatoms and/or one or more heavy metals to form an inorganic phase separable from the organic oil feedstock material. The upgradant hydrocarbon bonds to the oil feedstock material and increases the number of carbon atoms in the product. This increase in the number of carbon atoms of the product increases the energy value of the resulting oil feedstock.

  15. Incorporation of Hydrogen Bond Angle Dependency into the Generalized Solvation Free Energy Density Model.

    Science.gov (United States)

    Ma, Songling; Hwang, Sungbo; Lee, Sehan; Acree, William E; No, Kyoung Tai

    2018-03-30

    To describe the physically realistic solvation free energy surface of a molecule in a solvent, a generalized version of the solvation free energy density (G-SFED) calculation method has been developed. In the G-SFED model, the contribution from the hydrogen bond (HB) between a solute and a solvent to the solvation free energy was calculated as the product of the acidity of the donor and the basicity of the acceptor of an HB pair. The acidity and basicity parameters of a solute were derived using the summation of acidities and basicities of the respective acidic and basic functional groups of the solute, and that of the solvent was experimentally determined. Although the contribution of HBs to the solvation free energy could be evenly distributed to grid points on the surface of a molecule, the G-SFED model was still inadequate to describe the angle dependency of the HB of a solute with a polarizable continuum solvent. To overcome this shortcoming of the G-SFED model, the contribution of HBs was formulated using the geometric parameters of the grid points described in the HB coordinate system of the solute. We propose an HB angle dependency incorporated into the G-SFED model, i.e., the G-SFED-HB model, where the angular-dependent acidity and basicity densities are defined and parametrized with experimental data. The G-SFED-HB model was then applied to calculate the solvation free energies of organic molecules in water, various alcohols and ethers, and the log P values of diverse organic molecules, including peptides and a protein. Both the G-SFED model and the G-SFED-HB model reproduced the experimental solvation free energies with similar accuracy, whereas the distributions of the SFED on the molecular surface calculated by the G-SFED and G-SFED-HB models were quite different, especially for molecules having HB donors or acceptors. Since the angle dependency of HBs was included in the G-SFED-HB model, the SFED distribution of the G-SFED-HB model is well described

  16. Incorporating Mental Representations in Discrete Choice Models of Travel Behaviour : Modelling Approach and Empirical Application

    NARCIS (Netherlands)

    T.A. Arentze (Theo); B.G.C. Dellaert (Benedict); C.G. Chorus (Casper)

    2013-01-01

    textabstractWe introduce an extension of the discrete choice model to take into account individuals’ mental representation of a choice problem. We argue that, especially in daily activity and travel choices, the activated needs of an individual have an influence on the benefits he or she pursues in

  17. The Impact of Incorporating Chemistry to Numerical Weather Prediction Models: An Ensemble-Based Sensitivity Analysis

    Science.gov (United States)

    Barnard, P. A.; Arellano, A. F.

    2011-12-01

    Data assimilation has emerged as an integral part of numerical weather prediction (NWP). More recently, atmospheric chemistry processes have been incorporated into NWP models to provide forecasts and guidance on air quality. There is, however, a unique opportunity within this coupled system to investigate the additional benefit of constraining model dynamics and physics due to chemistry. Several studies have reported the strong interaction between chemistry and meteorology through radiation, transport, emission, and cloud processes. To examine its importance to NWP, we conduct an ensemble-based sensitivity analysis of meteorological fields to the chemical and aerosol fields within the Weather Research and Forecasting model coupled with Chemistry (WRF-Chem) and the Data Assimilation Research Testbed (DART) framework. In particular, we examine the sensitivity of the forecasts of surface temperature and related dynamical fields to the initial conditions of dust and aerosol concentrations in the model over the continental United States within the summer 2008 time period. We use an ensemble of meteorological and chemical/aerosol predictions within WRF-Chem/DART to calculate the sensitivities. This approach is similar to recent ensemble-based sensitivity studies in NWP. The use of an ensemble prediction is appealing because the analysis does not require the adjoint of the model, which to a certain extent becomes a limitation due to the rapidly evolving models and the increasing number of different observations. Here, we introduce this approach as applied to atmospheric chemistry. We also show our initial results of the calculated sensitivities from joint assimilation experiments using a combination of conventional meteorological observations from the National Centers for Environmental Prediction, retrievals of aerosol optical depth from NASA's Moderate Resolution Imaging Spectroradiometer, and retrievals of carbon monoxide from NASA's Measurements of Pollution in the

  18. Incorporating fragmentation and non-native species into distribution models to inform fluvial fish conservation.

    Science.gov (United States)

    Taylor, Andrew T; Papeş, Monica; Long, James M

    2018-02-01

    Fluvial fishes face increased imperilment from anthropogenic activities, but the specific factors contributing most to range declines are often poorly understood. For example, the range of the fluvial-specialist shoal bass (Micropterus cataractae) continues to decrease, yet how perceived threats have contributed to range loss is largely unknown. We used species distribution models to determine which factors contributed most to shoal bass range loss. We estimated a potential distribution based on natural abiotic factors and a series of currently occupied distributions that incorporated variables characterizing land cover, non-native species, and river fragmentation intensity (no fragmentation, dams only, and dams and large impoundments). We allowed interspecific relationships between non-native congeners and shoal bass to vary across fragmentation intensities. Results from the potential distribution model estimated shoal bass presence throughout much of their native basin, whereas models of currently occupied distribution showed that range loss increased as fragmentation intensified. Response curves from models of currently occupied distribution indicated a potential interaction between fragmentation intensity and the relationship between shoal bass and non-native congeners, wherein non-natives may be favored at the highest fragmentation intensity. Response curves also suggested that >100 km of interconnected, free-flowing stream fragments were necessary to support shoal bass presence. Model evaluation, including an independent validation, suggested that models had favorable predictive and discriminative abilities. Similar approaches that use readily available, diverse, geospatial data sets may deliver insights into the biology and conservation needs of other fluvial species facing similar threats. © 2017 Society for Conservation Biology.

  19. Methodology for the Incorporation of Passive Component Aging Modeling into the RAVEN/ RELAP-7 Environment

    Energy Technology Data Exchange (ETDEWEB)

    Mandelli, Diego; Rabiti, Cristian; Cogliati, Joshua; Alfonsi, Andrea; Askin Guler; Tunc Aldemir

    2014-11-01

    Passive system, structure and components (SSCs) will degrade over their operation life and this degradation may cause to reduction in the safety margins of a nuclear power plant. In traditional probabilistic risk assessment (PRA) using the event-tree/fault-tree methodology, passive SSC failure rates are generally based on generic plant failure data and the true state of a specific plant is not reflected realistically. To address aging effects of passive SSCs in the traditional PRA methodology [1] does consider physics based models that account for the operating conditions in the plant, however, [1] does not include effects of surveillance/inspection. This paper represents an overall methodology for the incorporation of aging modeling of passive components into the RAVEN/RELAP-7 environment which provides a framework for performing dynamic PRA. Dynamic PRA allows consideration of both epistemic and aleatory uncertainties (including those associated with maintenance activities) in a consistent phenomenological and probabilistic framework and is often needed when there is complex process/hardware/software/firmware/ human interaction [2]. Dynamic PRA has gained attention recently due to difficulties in the traditional PRA modeling of aging effects of passive components using physics based models and also in the modeling of digital instrumentation and control systems. RAVEN (Reactor Analysis and Virtual control Environment) [3] is a software package under development at the Idaho National Laboratory (INL) as an online control logic driver and post-processing tool. It is coupled to the plant transient code RELAP-7 (Reactor Excursion and Leak Analysis Program) also currently under development at INL [3], as well as RELAP 5 [4]. The overall methodology aims to: • Address multiple aging mechanisms involving large number of components in a computational feasible manner where sequencing of events is conditioned on the physical conditions predicted in a simulation

  20. Incorporating an extended dendritic growth model into the CAFE model for rapidly solidified non-dilute alloys

    Energy Technology Data Exchange (ETDEWEB)

    Ma, Jie; Wang, Bo [State Key Laboratory of Advanced Special Steel, Shanghai University, Shanghai 200072 (China); Shanghai Engineering Technology Research Center of Special Casting, Shanghai 201605 (China); Zhao, Shunli [Research Institute, Baoshan Iron & Steel Co., Ltd, Shanghai 201900 (China); Wu, Guangxin [State Key Laboratory of Advanced Special Steel, Shanghai University, Shanghai 200072 (China); Shanghai Engineering Technology Research Center of Special Casting, Shanghai 201605 (China); Zhang, Jieyu, E-mail: zjy6162@staff.shu.edu.cn [State Key Laboratory of Advanced Special Steel, Shanghai University, Shanghai 200072 (China); Shanghai Engineering Technology Research Center of Special Casting, Shanghai 201605 (China); Yang, Zhiliang [State Key Laboratory of Advanced Special Steel, Shanghai University, Shanghai 200072 (China); Shanghai Engineering Technology Research Center of Special Casting, Shanghai 201605 (China)

    2016-05-25

    We have extended the dendritic growth model first proposed by Boettinger, Coriell and Trivedi (here termed EBCT) for microstructure simulations of rapidly solidified non-dilute alloys. The temperature-dependent distribution coefficient, obtained from calculations of phase equilibria, and the continuous growth model (CGM) were adopted in the present EBCT model to describe the solute trapping behaviors. The temperature dependence of the physical properties, which were not used in previous dendritic growth models, were also considered in the present EBCT model. These extensions allow the present EBCT model to be used for microstructure simulations of non-dilute alloys. The comparison of the present EBCT model with the BCT model proves that the considerations of the distribution coefficient and physical properties are necessary for microstructure simulations, especially for small particles with high undercoolings. Finally, the EBCT model was incorporated into the cellular automaton-finite element (CAFE) model to simulate microstructures of gas-atomized ASP30 high speed steel particles that were then compared with experimental results. Both the simulated and experimental results reveal that a columnar dendritic microstructure preferentially forms in small particles and an equiaxed microstructure forms otherwise. The applications of the present EBCT model provide a convenient way to predict the microstructure of non-dilute alloys. - Highlights: • A dendritic growth model was developed considering non-equilibrium distribution coefficient. • The physical properties with temperature dependence were considered in the extended model. • The extended model can be used to non-dilute alloys and the extensions are necessary in small particles. • Microstructure of ASP30 steel was investigated using the present model and verified by experiment.

  1. Incorporation of a Wind Generator Model into a Dynamic Power Flow Analysis

    Directory of Open Access Journals (Sweden)

    Angeles-Camacho C.

    2011-07-01

    Full Text Available Wind energy is nowadays one of the most cost-effective and practical options for electric generation from renewable resources. However, increased penetration of wind generation causes the power networks to be more depend on, and vulnerable to, the varying wind speed. Modeling is a tool which can provide valuable information about the interaction between wind farms and the power network to which they are connected. This paper develops a realistic characterization of a wind generator. The wind generator model is incorporated into an algorithm to investigate its contribution to the stability of the power network in the time domain. The tool obtained is termed dynamic power flow. The wind generator model takes on account the wind speed and the reactive power consumption by induction generators. Dynamic power flow analysis is carried-out using real wind data at 10-minute time intervals collected for one meteorological station. The generation injected at one point into the network provides active power locally and is found to reduce global power losses. However, the power supplied is time-varying and causes fluctuations in voltage magnitude and power fl ows in transmission lines.

  2. Supersonic propulsion simulation by incorporating component models in the large perturbation inlet (LAPIN) computer code

    Science.gov (United States)

    Cole, Gary L.; Richard, Jacques C.

    1991-01-01

    An approach to simulating the internal flows of supersonic propulsion systems is presented. The approach is based on a fairly simple modification of the Large Perturbation Inlet (LAPIN) computer code. LAPIN uses a quasi-one dimensional, inviscid, unsteady formulation of the continuity, momentum, and energy equations. The equations are solved using a shock capturing, finite difference algorithm. The original code, developed for simulating supersonic inlets, includes engineering models of unstart/restart, bleed, bypass, and variable duct geometry, by means of source terms in the equations. The source terms also provide a mechanism for incorporating, with the inlet, propulsion system components such as compressor stages, combustors, and turbine stages. This requires each component to be distributed axially over a number of grid points. Because of the distributed nature of such components, this representation should be more accurate than a lumped parameter model. Components can be modeled by performance map(s), which in turn are used to compute the source terms. The general approach is described. Then, simulation of a compressor/fan stage is discussed to show the approach in detail.

  3. A Non-Isothermal Chemical Lattice Boltzmann Model Incorporating Thermal Reaction Kinetics and Enthalpy Changes

    Directory of Open Access Journals (Sweden)

    Stuart Bartlett

    2017-08-01

    Full Text Available The lattice Boltzmann method is an efficient computational fluid dynamics technique that can accurately model a broad range of complex systems. As well as single-phase fluids, it can simulate thermohydrodynamic systems and passive scalar advection. In recent years, it also gained attention as a means of simulating chemical phenomena, as interest in self-organization processes increased. This paper will present a widely-used and versatile lattice Boltzmann model that can simultaneously incorporate fluid dynamics, heat transfer, buoyancy-driven convection, passive scalar advection, chemical reactions and enthalpy changes. All of these effects interact in a physically accurate framework that is simple to code and readily parallelizable. As well as a complete description of the model equations, several example systems will be presented in order to demonstrate the accuracy and versatility of the method. New simulations, which analyzed the effect of a reversible reaction on the transport properties of a convecting fluid, will also be described in detail. This extra chemical degree of freedom was utilized by the system to augment its net heat flux. The numerical method outlined in this paper can be readily deployed for a vast range of complex flow problems, spanning a variety of scientific disciplines.

  4. Projecting cancer incidence using age-period-cohort models incorporating restricted cubic splines.

    Science.gov (United States)

    Rutherford, Mark J; Thompson, John R; Lambert, Paul C

    2012-11-05

    Age-period-cohort models provide a useful method for modeling incidence and mortality rates. There is great interest in estimating the rates of disease at given future time-points in order that plans can be made for the provision of the required future services. In the setting of using age-period-cohort models incorporating restricted cubic splines, a new technique for projecting incidence is proposed. The new technique projects the period and cohort terms linearly from 10 years within the range of the available data in order to give projections that are based on recent trends. The method is validated via a comparison with existing methods in the setting of Finnish cancer registry data. The reasons for the improvements seen for the newly proposed method are twofold. Firstly, improvements are seen due to the finer splitting of the timescale to give a more continuous estimate of the incidence rate. Secondly, the new method uses more recent trends to dictate the future projections than previously proposed methods.

  5. Incorporating Human-like Walking Variability in an HZD-Based Bipedal Model.

    Science.gov (United States)

    Martin, Anne E; Gregg, Robert D

    2016-08-01

    Predictive simulations of human walking could be used to investigate a wide range of questions. Promising moderately complex models have been developed using the robotics control technique hybrid zero dynamics (HZD). Existing simulations of human walking only consider the mean motion, so they cannot be used to investigate fall risk, which is correlated with variability. This work determines how to incorporate human-like variability into an HZD-based healthy human model to generate a more realistic gait. The key challenge is determining how to combine the existing mathematical description of variability with the dynamic model so that the biped is still able to walk without falling. To do so, the commanded motion is augmented with a sinusoidal variability function and a polynomial correction function. The variability function captures the variation in joint angles while the correction function prevents the variability function from growing uncontrollably. The necessity of the correction function and the improvements with a reduction of stance ankle variability are demonstrated via simulations. The variability in temporal measures is shown to be similar to experimental values.

  6. Estimating Biofuel Feedstock Water Footprints Using System Dynamics

    Energy Technology Data Exchange (ETDEWEB)

    Inman, Daniel; Warner, Ethan; Stright, Dana; Macknick, Jordan; Peck, Corey

    2016-07-01

    Increased biofuel production has prompted concerns about the environmental tradeoffs of biofuels compared to petroleum-based fuels. Biofuel production in general, and feedstock production in particular, is under increased scrutiny. Water footprinting (measuring direct and indirect water use) has been proposed as one measure to evaluate water use in the context of concerns about depleting rural water supplies through activities such as irrigation for large-scale agriculture. Water footprinting literature has often been limited in one or more key aspects: complete assessment across multiple water stocks (e.g., vadose zone, surface, and ground water stocks), geographical resolution of data, consistent representation of many feedstocks, and flexibility to perform scenario analysis. We developed a model called BioSpatial H2O using a system dynamics modeling and database framework. BioSpatial H2O could be used to consistently evaluate the complete water footprints of multiple biomass feedstocks at high geospatial resolutions. BioSpatial H2O has the flexibility to perform simultaneous scenario analysis of current and potential future crops under alternative yield and climate conditions. In this proof-of-concept paper, we modeled corn grain (Zea mays L.) and soybeans (Glycine max) under current conditions as illustrative results. BioSpatial H2O links to a unique database that houses annual spatially explicit climate, soil, and plant physiological data. Parameters from the database are used as inputs to our system dynamics model for estimating annual crop water requirements using daily time steps. Based on our review of the literature, estimated green water footprints are comparable to other modeled results, suggesting that BioSpatial H2O is computationally sound for future scenario analysis. Our modeling framework builds on previous water use analyses to provide a platform for scenario-based assessment. BioSpatial H2O's system dynamics is a flexible and user

  7. Chemical or feedstock recycling of WEEE products

    NARCIS (Netherlands)

    Tukker, A.

    2012-01-01

    This chapter reviews initiatives with regard to chemical or feedstock recycling of plastics waste from electrical and electronic products. eurostat estimates the amount of waste from electrical and electronic products that is collected is 2.2 million tonnes. Roughly 20% of this waste consists of

  8. Horse manure as feedstock for anaerobic digestion.

    Science.gov (United States)

    Hadin, Sa; Eriksson, Ola

    2016-10-01

    Horse keeping is of great economic, social and environmental benefit for society, but causes environmental impacts throughout the whole chain from feed production to manure treatment. According to national statistics, the number of horses in Sweden is continually increasing and is currently approximately 360,000. This in turn leads to increasing amounts of horse manure that have to be managed and treated. Current practices could cause local and global environmental impacts due to poor performance or lack of proper management. Horse manure with its content of nutrients and organic material can however contribute to fertilisation of arable land and recovery of renewable energy following anaerobic digestion. At present anaerobic digestion of horse manure is not a common treatment. In this paper the potential for producing biogas and biofertiliser from horse manure is analysed based on a thorough literature review in combination with mathematical modelling and simulations. Anaerobic digestion was chosen as it has a high degree of resource conservation, both in terms of energy (biogas) and nutrients (digestate). Important factors regarding manure characteristics and operating factors in the biogas plant are identified. Two crucial factors are the type and amount of bedding material used, which has strong implications for feedstock characteristics, and the type of digestion method applied (dry or wet process). Straw and waste paper are identified as the best materials in an energy point of view. While the specific methane yield decreases with a high amount of bedding, the bedding material still makes a positive contribution to the energy balance. Thermophilic digestion increases the methane generation rate and yield, compared with mesophilic digestion, but the total effect is negligible. Copyright © 2016. Published by Elsevier Ltd.

  9. Incorporating food web dynamics into ecological restoration: A modeling approach for river ecosystems

    Science.gov (United States)

    Bellmore, J. Ryan; Benjamin, Joseph R.; Newsom, Michael; Bountry, Jennifer A.; Dombroski, Daniel

    2017-01-01

    Restoration is frequently aimed at the recovery of target species, but also influences the larger food web in which these species participate. Effects of restoration on this broader network of organisms can influence target species both directly and indirectly via changes in energy flow through food webs. To help incorporate these complexities into river restoration planning we constructed a model that links river food web dynamics to in-stream physical habitat and riparian vegetation conditions. We present an application of the model to the Methow River, Washington (USA), a location of on-going restoration aimed at recovering salmon. Three restoration strategies were simulated: riparian vegetation restoration, nutrient augmentation via salmon carcass addition, and side-channel reconnection. We also added populations of nonnative aquatic snails and fish to the modeled food web to explore how changes in food web structure mediate responses to restoration. Simulations suggest that side-channel reconnection may be a better strategy than carcass addition and vegetation planting for improving conditions for salmon in this river segment. However, modeled responses were strongly sensitive to changes in the structure of the food web. The addition of nonnative snails and fish modified pathways of energy through the food web, which negated restoration improvements. This finding illustrates that forecasting responses to restoration may require accounting for the structure of food webs, and that changes in this structure—as might be expected with the spread of invasive species—could compromise restoration outcomes. Unlike habitat-based approaches to restoration assessment that focus on the direct effects of physical habitat conditions on single species of interest, our approach dynamically links the success of target organisms to the success of competitors, predators, and prey. By elucidating the direct and indirect pathways by which restoration affects target species

  10. MIST: An Open Source Environmental Modelling Programming Language Incorporating Easy to Use Data Parallelism.

    Science.gov (United States)

    Bellerby, Tim

    2014-05-01

    Model Integration System (MIST) is open-source environmental modelling programming language that directly incorporates data parallelism. The language is designed to enable straightforward programming structures, such as nested loops and conditional statements to be directly translated into sequences of whole-array (or more generally whole data-structure) operations. MIST thus enables the programmer to use well-understood constructs, directly relating to the mathematical structure of the model, without having to explicitly vectorize code or worry about details of parallelization. A range of common modelling operations are supported by dedicated language structures operating on cell neighbourhoods rather than individual cells (e.g.: the 3x3 local neighbourhood needed to implement an averaging image filter can be simply accessed from within a simple loop traversing all image pixels). This facility hides details of inter-process communication behind more mathematically relevant descriptions of model dynamics. The MIST automatic vectorization/parallelization process serves both to distribute work among available nodes and separately to control storage requirements for intermediate expressions - enabling operations on very large domains for which memory availability may be an issue. MIST is designed to facilitate efficient interpreter based implementations. A prototype open source interpreter is available, coded in standard FORTRAN 95, with tools to rapidly integrate existing FORTRAN 77 or 95 code libraries. The language is formally specified and thus not limited to FORTRAN implementation or to an interpreter-based approach. A MIST to FORTRAN compiler is under development and volunteers are sought to create an ANSI-C implementation. Parallel processing is currently implemented using OpenMP. However, parallelization code is fully modularised and could be replaced with implementations using other libraries. GPU implementation is potentially possible.

  11. Incorporating food web dynamics into ecological restoration: a modeling approach for river ecosystems.

    Science.gov (United States)

    Bellmore, J Ryan; Benjamin, Joseph R; Newsom, Michael; Bountry, Jennifer A; Dombroski, Daniel

    2017-04-01

    Restoration is frequently aimed at the recovery of target species, but also influences the larger food web in which these species participate. Effects of restoration on this broader network of organisms can influence target species both directly and indirectly via changes in energy flow through food webs. To help incorporate these complexities into river restoration planning, we constructed a model that links river food web dynamics to in-stream physical habitat and riparian vegetation conditions. We present an application of the model to the Methow River, Washington, USA, a location of on-going restoration aimed at recovering salmon. Three restoration strategies were simulated: riparian vegetation restoration, nutrient augmentation via salmon carcass addition, and side channel reconnection. We also added populations of nonnative aquatic snails and fish to the modeled food web to explore how changes in food web structure mediate responses to restoration. Simulations suggest that side channel reconnection may be a better strategy than carcass addition and vegetation planting for improving conditions for salmon in this river segment. However, modeled responses were strongly sensitive to changes in the structure of the food web. The addition of nonnative snails and fish modified pathways of energy through the food web, which negated restoration improvements. This finding illustrates that forecasting responses to restoration may require accounting for the structure of food webs, and that changes in this structure, as might be expected with the spread of invasive species, could compromise restoration outcomes. Unlike habitat-based approaches to restoration assessment that focus on the direct effects of physical habitat conditions on single species of interest, our approach dynamically links the success of target organisms to the success of competitors, predators, and prey. By elucidating the direct and indirect pathways by which restoration affects target species

  12. A land use regression model incorporating data on industrial point source pollution.

    Science.gov (United States)

    Chen, Li; Wang, Yuming; Li, Peiwu; Ji, Yaqin; Kong, Shaofei; Li, Zhiyong; Bai, Zhipeng

    2012-01-01

    Advancing the understanding of the spatial aspects of air pollution in the city regional environment is an area where improved methods can be of great benefit to exposure assessment and policy support. We created land use regression (LUR) models for SO2, NO2 and PM10 for Tianjin, China. Traffic volumes, road networks, land use data, population density, meteorological conditions, physical conditions and satellite-derived greenness, brightness and wetness were used for predicting SO2, NO2 and PM10 concentrations. We incorporated data on industrial point sources to improve LUR model performance. In order to consider the impact of different sources, we calculated the PSIndex, LSIndex and area of different land use types (agricultural land, industrial land, commercial land, residential land, green space and water area) within different buffer radii (1 to 20 km). This method makes up for the lack of consideration of source impact based on the LUR model. Remote sensing-derived variables were significantly correlated with gaseous pollutant concentrations such as SO2 and NO2. R2 values of the multiple linear regression equations for SO2, NO2 and PM10 were 0.78, 0.89 and 0.84, respectively, and the RMSE values were 0.32, 0.18 and 0.21, respectively. Model predictions at validation monitoring sites went well with predictions generally within 15% of measured values. Compared to the relationship between dependent variables and simple variables (such as traffic variables or meteorological condition variables), the relationship between dependent variables and integrated variables was more consistent with a linear relationship. Such integration has a discernable influence on both the overall model prediction and health effects assessment on the spatial distribution of air pollution in the city region.

  13. Sustainable Use of Biotechnology for Bioenergy Feedstocks

    Science.gov (United States)

    Moon, Hong S.; Abercrombie, Jason M.; Kausch, Albert P.; Stewart, C. Neal

    2010-10-01

    Done correctly, cellulosic bioenergy should be both environmentally and economically beneficial. Carbon sequestration and decreased fossil fuel use are both worthy goals in developing next-generation biofuels. We believe that biotechnology will be needed to significantly improve yield and digestibility of dedicated perennial herbaceous biomass feedstocks, such as switchgrass and Miscanthus, which are native to the US and China, respectively. This Forum discusses the sustainability of herbaceous feedstocks relative to the regulation of biotechnology with regards to likely genetically engineered traits. The Forum focuses on two prominent countries wishing to develop their bioeconomies: the US and China. These two countries also share a political desire and regulatory frameworks to enable the commercialization and wide release of transgenic feedstocks with appropriate and safe new genetics. In recent years, regulators in both countries perform regular inspections of transgenic field releases and seriously consider compliance issues, even though the US framework is considered to be more mature and stringent. Transgene flow continues to be a pertinent environmental and regulatory issue with regards to transgenic plants. This concern is largely driven by consumer issues and ecological uncertainties. Regulators are concerned about large-scale releases of transgenic crops that have sexually compatible crops or wild relatives that can stably harbor transgenes via hybridization and introgression. Therefore, prior to the commercialization or extensive field testing of transgenic bioenergy feedstocks, we recommend that mechanisms that ensure biocontainment of transgenes be instituted, especially for perennial grasses. A cautionary case study will be presented in which a plant’s biology and ecology conspired against regulatory constraints in a non-biomass crop perennial grass (creeping bentgrass, Agrostis stolonifera), in which biocontainment was not attained. Appropriate

  14. Estimating disperser abundance using open population models that incorporate data from continuous detection PIT arrays

    Science.gov (United States)

    Dzul, Maria C.; Yackulic, Charles B.; Korman, Josh

    2017-01-01

    Autonomous passive integrated transponder (PIT) tag antenna systems continuously detect individually marked organisms at one or more fixed points over long time periods. Estimating abundance using data from autonomous antennae can be challenging, because these systems do not detect unmarked individuals. Here we pair PIT antennae data from a tributary with mark-recapture sampling data in a mainstem river to estimate the number of fish moving from the mainstem to the tributary. We then use our model to estimate abundance of non-native rainbow trout Oncorhynchus mykiss that move from the Colorado River to the Little Colorado River (LCR), the latter of which is important spawning and rearing habitat for federally-endangered humpback chub Gila cypha. We estimate 226 rainbow trout (95% CI: 127-370) entered the LCR from October 2013-April 2014. We discuss the challenges of incorporating detections from autonomous PIT antenna systems into mark-recapture population models, particularly in regards to using information about spatial location to estimate movement and detection probabilities.

  15. A systematic procedure for the incorporation of common cause events into risk and reliability models

    International Nuclear Information System (INIS)

    Fleming, K.N.; Mosleh, A.; Deremer, R.K.

    1986-01-01

    Common cause events are an important class of dependent events with respect to their contribution to system unavailability and to plant risk. Unfortunately, these events have not been treated with any king of consistency in applied risk studies over the past decade. Many probabilistic risk assessments (PRA) have not included these events at all, and those that have did not employ the kind of systematic procedures that are needed to achieve consistency, accuracy, and credibility in this area of PRA methodology. In this paper, the authors report on the progress recently made in the development of a systematic approach for incorporating common cause events into applied risk and reliability evaluations. This approach takes advantage of experience from recently completed PRAs and is the result of a project, sponsored by the Electric Power Research Institute (EPRI), in which procedures for dependent events analysis are being developed. Described in this paper is a general framework for system-level common cause failure (CCF) analysis and its application to a three-train auxiliary feedwater system. Within this general framework, three parametric CCF models are compared, including the basic parameter (BP), multiple Greek letter (MGL), and binominal failure rate (BFR) models. Pitfalls of not following the recommended procedure are discussed, and some old issues, such as the benefits of redundancy and diversity, are reexamined. (orig.)

  16. Conditional spectrum computation incorporating multiple causal earthquakes and ground-motion prediction models

    Science.gov (United States)

    Lin, Ting; Harmsen, Stephen C.; Baker, Jack W.; Luco, Nicolas

    2013-01-01

    The conditional spectrum (CS) is a target spectrum (with conditional mean and conditional standard deviation) that links seismic hazard information with ground-motion selection for nonlinear dynamic analysis. Probabilistic seismic hazard analysis (PSHA) estimates the ground-motion hazard by incorporating the aleatory uncertainties in all earthquake scenarios and resulting ground motions, as well as the epistemic uncertainties in ground-motion prediction models (GMPMs) and seismic source models. Typical CS calculations to date are produced for a single earthquake scenario using a single GMPM, but more precise use requires consideration of at least multiple causal earthquakes and multiple GMPMs that are often considered in a PSHA computation. This paper presents the mathematics underlying these more precise CS calculations. Despite requiring more effort to compute than approximate calculations using a single causal earthquake and GMPM, the proposed approach produces an exact output that has a theoretical basis. To demonstrate the results of this approach and compare the exact and approximate calculations, several example calculations are performed for real sites in the western United States. The results also provide some insights regarding the circumstances under which approximate results are likely to closely match more exact results. To facilitate these more precise calculations for real applications, the exact CS calculations can now be performed for real sites in the United States using new deaggregation features in the U.S. Geological Survey hazard mapping tools. Details regarding this implementation are discussed in this paper.

  17. Incorporating a Wheeled Vehicle Model in a New Monocular Visual Odometry Algorithm for Dynamic Outdoor Environments

    Science.gov (United States)

    Jiang, Yanhua; Xiong, Guangming; Chen, Huiyan; Lee, Dah-Jye

    2014-01-01

    This paper presents a monocular visual odometry algorithm that incorporates a wheeled vehicle model for ground vehicles. The main innovation of this algorithm is to use the single-track bicycle model to interpret the relationship between the yaw rate and side slip angle, which are the two most important parameters that describe the motion of a wheeled vehicle. Additionally, the pitch angle is also considered since the planar-motion hypothesis often fails due to the dynamic characteristics of wheel suspensions and tires in real-world environments. Linearization is used to calculate a closed-form solution of the motion parameters that works as a hypothesis generator in a RAndom SAmple Consensus (RANSAC) scheme to reduce the complexity in solving equations involving trigonometric. All inliers found are used to refine the winner solution through minimizing the reprojection error. Finally, the algorithm is applied to real-time on-board visual localization applications. Its performance is evaluated by comparing against the state-of-the-art monocular visual odometry methods using both synthetic data and publicly available datasets over several kilometers in dynamic outdoor environments. PMID:25256109

  18. Incorporating Measurement Error from Modeled Air Pollution Exposures into Epidemiological Analyses.

    Science.gov (United States)

    Samoli, Evangelia; Butland, Barbara K

    2017-12-01

    Outdoor air pollution exposures used in epidemiological studies are commonly predicted from spatiotemporal models incorporating limited measurements, temporal factors, geographic information system variables, and/or satellite data. Measurement error in these exposure estimates leads to imprecise estimation of health effects and their standard errors. We reviewed methods for measurement error correction that have been applied in epidemiological studies that use model-derived air pollution data. We identified seven cohort studies and one panel study that have employed measurement error correction methods. These methods included regression calibration, risk set regression calibration, regression calibration with instrumental variables, the simulation extrapolation approach (SIMEX), and methods under the non-parametric or parameter bootstrap. Corrections resulted in small increases in the absolute magnitude of the health effect estimate and its standard error under most scenarios. Limited application of measurement error correction methods in air pollution studies may be attributed to the absence of exposure validation data and the methodological complexity of the proposed methods. Future epidemiological studies should consider in their design phase the requirements for the measurement error correction method to be later applied, while methodological advances are needed under the multi-pollutants setting.

  19. Incorporating a wheeled vehicle model in a new monocular visual odometry algorithm for dynamic outdoor environments.

    Science.gov (United States)

    Jiang, Yanhua; Xiong, Guangming; Chen, Huiyan; Lee, Dah-Jye

    2014-09-01

    This paper presents a monocular visual odometry algorithm that incorporates a wheeled vehicle model for ground vehicles. The main innovation of this algorithm is to use the single-track bicycle model to interpret the relationship between the yaw rate and side slip angle, which are the two most important parameters that describe the motion of a wheeled vehicle. Additionally, the pitch angle is also considered since the planar-motion hypothesis often fails due to the dynamic characteristics of wheel suspensions and tires in real-world environments. Linearization is used to calculate a closed-form solution of the motion parameters that works as a hypothesis generator in a RAndom SAmple Consensus (RANSAC) scheme to reduce the complexity in solving equations involving trigonometric. All inliers found are used to refine the winner solution through minimizing the reprojection error. Finally, the algorithm is applied to real-time on-board visual localization applications. Its performance is evaluated by comparing against the state-of-the-art monocular visual odometry methods using both synthetic data and publicly available datasets over several kilometers in dynamic outdoor environments.

  20. Incorporating a Wheeled Vehicle Model in a New Monocular Visual Odometry Algorithm for Dynamic Outdoor Environments

    Directory of Open Access Journals (Sweden)

    Yanhua Jiang

    2014-09-01

    Full Text Available This paper presents a monocular visual odometry algorithm that incorporates a wheeled vehicle model for ground vehicles. The main innovation of this algorithm is to use the single-track bicycle model to interpret the relationship between the yaw rate and side slip angle, which are the two most important parameters that describe the motion of a wheeled vehicle. Additionally, the pitch angle is also considered since the planar-motion hypothesis often fails due to the dynamic characteristics of wheel suspensions and tires in real-world environments. Linearization is used to calculate a closed-form solution of the motion parameters that works as a hypothesis generator in a RAndom SAmple Consensus (RANSAC scheme to reduce the complexity in solving equations involving trigonometric. All inliers found are used to refine the winner solution through minimizing the reprojection error. Finally, the algorithm is applied to real-time on-board visual localization applications. Its performance is evaluated by comparing against the state-of-the-art monocular visual odometry methods using both synthetic data and publicly available datasets over several kilometers in dynamic outdoor environments.

  1. Alternative, Renewable and Novel Feedstocks for Producing Chemicals

    Energy Technology Data Exchange (ETDEWEB)

    none,

    2007-07-01

    Vision2020 and ITP directed the Alternative, Renewable and Novel Feedstocks project to identify industrial options and to determine the work required to make alternative, renewable and novel feedstock options attractive to the U.S. chemicals industry. This report presents the Alternative, Renewable and Novel Feedstocks project findings which were based on a technology review and industry workshop.

  2. Incorporating Prognostic Marine Nitrogen Fixers and Related Bio-Physical Feedbacks in an Earth System Model

    Science.gov (United States)

    Paulsen, H.; Ilyina, T.; Six, K. D.

    2016-02-01

    Marine nitrogen fixers play a fundamental role in the oceanic nitrogen and carbon cycles by providing a major source of `new' nitrogen to the euphotic zone that supports biological carbon export and sequestration. Furthermore, nitrogen fixers may regionally have a direct impact on ocean physics and hence the climate system as they form extensive surface mats which can increase light absorption and surface albedo and reduce the momentum input by wind. Resulting alterations in temperature and stratification may feed back on nitrogen fixers' growth itself.We incorporate nitrogen fixers as a prognostic 3D tracer in the ocean biogeochemical component (HAMOCC) of the Max Planck Institute Earth system model and assess for the first time the impact of related bio-physical feedbacks on biogeochemistry and the climate system.The model successfully reproduces recent estimates of global nitrogen fixation rates, as well as the observed distribution of nitrogen fixers, covering large parts of the tropical and subtropical oceans. First results indicate that including bio-physical feedbacks has considerable effects on the upper ocean physics in this region. Light absorption by nitrogen fixers leads locally to surface heating, subsurface cooling, and mixed layer depth shoaling in the subtropical gyres. As a result, equatorial upwelling is increased, leading to surface cooling at the equator. This signal is damped by the effect of the reduced wind stress due to the presence of cyanobacteria mats, which causes a reduction in the wind-driven circulation, and hence a reduction in equatorial upwelling. The increase in surface albedo due to nitrogen fixers has only inconsiderable effects. The response of nitrogen fixers' growth to the alterations in temperature and stratification varies regionally. Simulations with the fully coupled Earth system model are in progress to assess the implications of the biologically induced changes in upper ocean physics for the global climate system.

  3. A Fault-Cored Anticline Boundary Element Model Incorporating the Combined Fault Slip and Buckling Mechanisms

    Directory of Open Access Journals (Sweden)

    Wen-Jeng Huang

    2016-02-01

    Full Text Available We develop a folding boundary element model in a medium containing a fault and elastic layers to show that anticlines growing over slipping reverse faults can be significantly amplified by mechanical layering buckling under horizontal shortening. Previous studies suggested that folds over blind reverse faults grow primarily during deformation increments associated with slips on the fault during and immediately after earthquakes. Under this assumption, the potential for earthquakes on blind faults can be determined directly from fold geometry because the amount of slip on the fault can be estimated directly from the fold geometry using the solution for a dislocation in an elastic half-space. Studies that assume folds grown solely by slip on a fault may therefore significantly overestimate fault slip. Our boundary element technique demonstrates that the fold amplitude produced in a medium containing a fault and elastic layers with free slip and subjected to layer-parallel shortening can grow to more than twice the fold amplitude produced in homogeneous media without mechanical layering under the same amount of shortening. In addition, the fold wavelengths produced by the combined fault slip and buckling mechanisms may be narrower than folds produced by fault slip in an elastic half space by a factor of two. We also show that subsurface fold geometry of the Kettleman Hills Anticline in Central California inferred from seismic reflection image is consistent with a model that incorporates layer buckling over a dipping, blind reverse fault and the coseismic uplift pattern produced during a 1985 earthquake centered over the anticline forelimb is predicted by the model.

  4. Using a cognitive architecture in educational and recreational games : How to incorporate a model in your App

    NARCIS (Netherlands)

    Taatgen, Niels A.; de Weerd, Harmen; Reitter, David; Ritter, Frank

    2016-01-01

    We present a Swift re-implementation of the ACT-R cognitive architecture, which can be used to quickly build iOS Apps that incorporate an ACT-R model as a core feature. We discuss how this implementation can be used in an example model, and explore the breadth of possibilities by presenting six Apps

  5. Adolescent Decision-Making Processes regarding University Entry: A Model Incorporating Cultural Orientation, Motivation and Occupational Variables

    Science.gov (United States)

    Jung, Jae Yup

    2013-01-01

    This study tested a newly developed model of the cognitive decision-making processes of senior high school students related to university entry. The model incorporated variables derived from motivation theory (i.e. expectancy-value theory and the theory of reasoned action), literature on cultural orientation and occupational considerations. A…

  6. Incorporating genetic variation into a model of budburst phenology of coast Douglas-fir (Pseudotsuga menziesii var

    Science.gov (United States)

    Peter J. Gould; Constance A. Harrington; Bradley J. St Clair

    2011-01-01

    Models to predict budburst and other phenological events in plants are needed to forecast how climate change may impact ecosystems and for the development of mitigation strategies. Differences among genotypes are important to predicting phenological events in species that show strong clinal variation in adaptive traits. We present a model that incorporates the effects...

  7. Incorporation of Fine-Grained Sediment Erodibility Measurements into Sediment Transport Modeling, Capitol Lake, Washington

    Science.gov (United States)

    Stevens, Andrew W.; Gelfenbaum, Guy; Elias, Edwin; Jones, Craig

    2008-01-01

    lab with Sedflume, an apparatus for measuring sediment erosion-parameters. In this report, we present results of the characterization of fine-grained sediment erodibility within Capitol Lake. The erodibility data were incorporated into the previously developed hydrodynamic and sediment transport model. Model simulations using the measured erodibility parameters were conducted to provide more robust estimates of the overall magnitudes and spatial patterns of sediment transport resulting from restoration of the Deschutes Estuary.

  8. A diagnostic model incorporating P50 sensory gating and neuropsychological tests for schizophrenia.

    Directory of Open Access Journals (Sweden)

    Jia-Chi Shan

    Full Text Available OBJECTIVES: Endophenotypes in schizophrenia research is a contemporary approach to studying this heterogeneous mental illness, and several candidate neurophysiological markers (e.g. P50 sensory gating and neuropsychological tests (e.g. Continuous Performance Test (CPT and Wisconsin Card Sorting Test (WCST have been proposed. However, the clinical utility of a single marker appears to be limited. In the present study, we aimed to construct a diagnostic model incorporating P50 sensory gating with other neuropsychological tests in order to improve the clinical utility. METHODS: We recruited clinically stable outpatients meeting DSM-IV criteria of schizophrenia and age- and gender-matched healthy controls. Participants underwent P50 sensory gating experimental sessions and batteries of neuropsychological tests, including CPT, WCST and Wechsler Adult Intelligence Scale Third Edition (WAIS-III. RESULTS: A total of 106 schizophrenia patients and 74 healthy controls were enrolled. Compared with healthy controls, the patient group had significantly a larger S2 amplitude, and thus poorer P50 gating ratio (gating ratio = S2/S1. In addition, schizophrenia patients had a poorer performance on neuropsychological tests. We then developed a diagnostic model by using multivariable logistic regression analysis to differentiate patients from healthy controls. The final model included the following covariates: abnormal P50 gating (defined as P50 gating ratio >0.4, three subscales derived from the WAIS-III (Arithmetic, Block Design, and Performance IQ, sensitivity index from CPT and smoking status. This model had an adequate accuracy (concordant percentage = 90.4%; c-statistic = 0.904; Hosmer-Lemeshow Goodness-of-Fit Test, p = 0.64>0.05. CONCLUSION: To the best of our knowledge, this is the largest study to date using P50 sensory gating in subjects of Chinese ethnicity and the first to use P50 sensory gating along with other neuropsychological tests

  9. Biofuel Feedstock Assessment For Selected Countries

    Energy Technology Data Exchange (ETDEWEB)

    Kline, Keith L [ORNL; Oladosu, Gbadebo A [ORNL; Wolfe, Amy K [ORNL; Perlack, Robert D [ORNL; Dale, Virginia H [ORNL

    2008-02-01

    Findings from biofuel feedstock production assessments and projections of future supply are presented and discussed. The report aims to improve capabilities to assess the degree to which imported biofuel could contribute to meeting future U.S. targets to reduce dependence on imported oil. The study scope was focused to meet time and resource requirements. A screening process identified Argentina, Brazil, Canada, China, Colombia, India, Mexico, and the Caribbean Basin Initiative (CBI) region for initial analysis, given their likely role in future feedstock supply relevant to U.S. markets. Supply curves for selected feedstocks in these countries are projected for 2012, 2017 and 2027. The supply functions, along with calculations to reflect estimated supplies available for export and/or biofuel production, were provided to DOE for use in a broader energy market allocation study. Potential cellulosic supplies from crop and forestry residues and perennials were also estimated for 2017 and 2027. The analysis identified capacity to potentially double or triple feedstock production by 2017 in some cases. A majority of supply growth is derived from increasing the area cultivated (especially sugarcane in Brazil). This is supplemented by improving yields and farming practices. Most future supplies of corn and wheat are projected to be allocated to food and feed. Larger shares of future supplies of sugarcane, soybean and palm oil production will be available for export or biofuel. National policies are catalyzing investments in biofuel industries to meet targets for fuel blending that generally fall in the 5-10% range. Social and environmental concerns associated with rapid expansion of feedstock production are considered. If the 2017 projected feedstock supply calculated as 'available' for export or biofuel were converted to fuel, it would represent the equivalent of about 38 billion gallons of gasoline. Sugarcane and bagasse dominate the available supply

  10. Biofuel production from microalgae as feedstock: current status and potential.

    Science.gov (United States)

    Han, Song-Fang; Jin, Wen-Biao; Tu, Ren-Jie; Wu, Wei-Min

    2015-06-01

    Algal biofuel has become an attractive alternative of petroleum-based fuels in the past decade. Microalgae have been proposed as a feedstock to produce biodiesel, since they are capable of mitigating CO2 emission and accumulating lipids with high productivity. This article is an overview of the updated status of biofuels, especially biodiesel production from microalgae including fundamental research, culture selection and engineering process development; it summarizes research on mathematical and life cycle modeling on algae growth and biomass production; and it updates global efforts of research and development and commercialization attempts. The major challenges are also discussed.

  11. Lignin-containing Feedstock Hydrogenolysis for Biofuel Component Production

    OpenAIRE

    Elena Shimanskaya; Аntonina A. Stepacheva; Esther Sulman; Evgeny Rebrov; Valentina Matveeva

    2018-01-01

    In this paper, the commercial 5%Pd/C and 5%Pt/C catalysts and synthesized 5%Pt/MN-270 and 5%Pd/MN-270 were used in the hydrogenolysis of lignocellulosic material (softwood sawdust) to obtain liquid fuels in the form of hydrocarbons. As lignin has a very complex structure, anisole was used as a model compound. It was found that the use Pt-containing catalysts based on hypercrosslinked polystyrene in both processes of anisole and lignin-containing feedstock conversion allowed obtaining the high...

  12. Incorporating organizational factors into probabilistic safety assessment of nuclear power plants through canonical probabilistic models

    International Nuclear Information System (INIS)

    Galan, S.F.; Mosleh, A.; Izquierdo, J.M.

    2007-01-01

    The ω-factor approach is a method that explicitly incorporates organizational factors into Probabilistic safety assessment of nuclear power plants. Bayesian networks (BNs) are the underlying formalism used in this approach. They have a structural part formed by a graph whose nodes represent organizational variables, and a parametric part that consists of conditional probabilities, each of them quantifying organizational influences between one variable and its parents in the graph. The aim of this paper is twofold. First, we discuss some important limitations of current procedures in the ω-factor approach for either assessing conditional probabilities from experts or estimating them from data. We illustrate the discussion with an example that uses data from Licensee Events Reports of nuclear power plants for the estimation task. Second, we introduce significant improvements in the way BNs for the ω-factor approach can be constructed, so that parameter acquisition becomes easier and more intuitive. The improvements are based on the use of noisy-OR gates as model of multicausal interaction between each BN node and its parents

  13. Incorporating organizational factors into probabilistic safety assessment of nuclear power plants through canonical probabilistic models

    Energy Technology Data Exchange (ETDEWEB)

    Galan, S.F. [Dpto. de Inteligencia Artificial, E.T.S.I. Informatica (UNED), Juan del Rosal, 16, 28040 Madrid (Spain)]. E-mail: seve@dia.uned.es; Mosleh, A. [2100A Marie Mount Hall, Materials and Nuclear Engineering Department, University of Maryland, College Park, MD 20742 (United States)]. E-mail: mosleh@umd.edu; Izquierdo, J.M. [Area de Modelado y Simulacion, Consejo de Seguridad Nuclear, Justo Dorado, 11, 28040 Madrid (Spain)]. E-mail: jmir@csn.es

    2007-08-15

    The {omega}-factor approach is a method that explicitly incorporates organizational factors into Probabilistic safety assessment of nuclear power plants. Bayesian networks (BNs) are the underlying formalism used in this approach. They have a structural part formed by a graph whose nodes represent organizational variables, and a parametric part that consists of conditional probabilities, each of them quantifying organizational influences between one variable and its parents in the graph. The aim of this paper is twofold. First, we discuss some important limitations of current procedures in the {omega}-factor approach for either assessing conditional probabilities from experts or estimating them from data. We illustrate the discussion with an example that uses data from Licensee Events Reports of nuclear power plants for the estimation task. Second, we introduce significant improvements in the way BNs for the {omega}-factor approach can be constructed, so that parameter acquisition becomes easier and more intuitive. The improvements are based on the use of noisy-OR gates as model of multicausal interaction between each BN node and its parents.

  14. Incorporating numerical modelling into estimates of the detection capability of the IMS infrasound network

    Science.gov (United States)

    Le Pichon, A.; Ceranna, L.

    2011-12-01

    To monitor compliance with the Comprehensive Nuclear-Test-Ban Treaty (CTBT), a dedicated International Monitoring System (IMS) is being deployed. Recent global scale observations recorded by this network confirm that its detection capability is highly variable in space and time. Previous studies estimated the radiated source energy from remote observations using empirical yield-scaling relations which account for the along-path stratospheric winds. Although the empirical wind correction reduces the variance in the explosive energy versus pressure relationship, strong variability remains in the yield estimate. Today, numerical modelling techniques provide a basis to better understand the role of different factors describing the source and the atmosphere that influence propagation predictions. In this study, the effects of the source frequency and the stratospheric wind speed are simulated. In order to characterize fine-scale atmospheric structures which are excluded from the current atmospheric specifications, model predictions are further enhanced by the addition of perturbation terms. Thus, a theoretical attenuation relation is developed from massive numerical simulations using the Parabolic Equation method. Compared with previous studies, our approach provides a more realistic physical description of infrasound propagation. We obtain a new relation combining a near-field and far-field term which account for the effects of both geometrical spreading and dissipation on the pressure wave attenuation. By incorporating real ambient infrasound noise at the receivers which significantly limits the ability to detect and identify signals of interest, the minimum detectable source amplitude can be derived in a broad frequency range. Empirical relations between the source spectrum and the yield of explosions are used to infer detection thresholds in tons of TNT equivalent. In the context of the future verification of the CTBT, the obtained attenuation relation quantifies

  15. Incorporating Geological Effects in Modeling of Revegetation Strategies for Salt-Affected Landscapes.

    Science.gov (United States)

    Clarke; Bell; Hobbs; George

    1999-07-01

    / This paper synthesizes results of research into the impact that major faults have on dryland salinity and the development of revegetation treatments in the wheatbelt of Western Australia. Currently, landscape planning does not routinely incorporate geology, but this research shows that faults can have a dramatic impact on land and stream salinization and on the effectiveness of revegetation treatments, and evidence exists that other geological features can have a similar influence. This research shows that faults can be identified from airborne magnetic data, they can be assigned a characteristic hydraulic conductivity based on simple borehole tests, and four other geological features that are expected to affect land and stream salinity could be identified in airborne geophysical data. A geological theme map could then be created to which characteristic hydraulic conductivities could be assigned for use in computer groundwater models to improve prediction of the effectiveness of revegetation treatments and thus enhance the landscape planning process. The work highlights the difficulties of using standard sampling and statistical techniques to investigate regional phenomena and presents an integrated approach combining small-scale sampling with broad-scale observations to provide input into a modeling exercise. It is suggested that such approaches are vital if landscape- and regional-scale processes are to be understood and managed. The way in which the problem is perceived (holistically or piecemeal) affects the way treatments are designed and their effectiveness: past approaches have failed to integrate the various scales and processes involved. Effective solutions require an integrated holistic response.KEY WORDS: Dryland salinity; Geology; Landscape; Revegetation integrationhttp://link.springer-ny.com/link/service/journals/00267/bibs/24n1p99.html

  16. Processing Cost Analysis for Biomass Feedstocks

    Energy Technology Data Exchange (ETDEWEB)

    Badger, P.C.

    2002-11-20

    The receiving, handling, storing, and processing of woody biomass feedstocks is an overlooked component of biopower systems. The purpose of this study was twofold: (1) to identify and characterize all the receiving, handling, storing, and processing steps required to make woody biomass feedstocks suitable for use in direct combustion and gasification applications, including small modular biopower (SMB) systems, and (2) to estimate the capital and operating costs at each step. Since biopower applications can be varied, a number of conversion systems and feedstocks required evaluation. In addition to limiting this study to woody biomass feedstocks, the boundaries of this study were from the power plant gate to the feedstock entry point into the conversion device. Although some power plants are sited at a source of wood waste fuel, it was assumed for this study that all wood waste would be brought to the power plant site. This study was also confined to the following three feedstocks (1) forest residues, (2) industrial mill residues, and (3) urban wood residues. Additionally, the study was confined to grate, suspension, and fluidized bed direct combustion systems; gasification systems; and SMB conversion systems. Since scale can play an important role in types of equipment, operational requirements, and capital and operational costs, this study examined these factors for the following direct combustion and gasification system size ranges: 50, 20, 5, and 1 MWe. The scope of the study also included: Specific operational issues associated with specific feedstocks (e.g., bark and problems with bridging); Opportunities for reducing handling, storage, and processing costs; How environmental restrictions can affect handling and processing costs (e.g., noise, commingling of treated wood or non-wood materials, emissions, and runoff); and Feedstock quality issues and/or requirements (e.g., moisture, particle size, presence of non-wood materials). The study found that over the

  17. Bioenergy Feedstock Development Program Status Report

    Energy Technology Data Exchange (ETDEWEB)

    Kszos, L.A.

    2001-02-09

    The U.S. Department of Energy's (DOE's) Bioenergy Feedstock Development Program (BFDP) at Oak Ridge National Laboratory (ORNL) is a mission-oriented program of research and analysis whose goal is to develop and demonstrate cropping systems for producing large quantities of low-cost, high-quality biomass feedstocks for use as liquid biofuels, biomass electric power, and/or bioproducts. The program specifically supports the missions and goals of DOE's Office of Fuels Development and DOE's Office of Power Technologies. ORNL has provided technical leadership and field management for the BFDP since DOE began energy crop research in 1978. The major components of the BFDP include energy crop selection and breeding; crop management research; environmental assessment and monitoring; crop production and supply logistics operational research; integrated resource analysis and assessment; and communications and outreach. Research into feedstock supply logistics has recently been added and will become an integral component of the program.

  18. Incorporating classic adsorption isotherms into modern surface complexation models: implications for sorption of radionuclides

    International Nuclear Information System (INIS)

    Kulik, D.A.

    2005-01-01

    Full text of publication follows: Computer-aided surface complexation models (SCM) tend to replace the classic adsorption isotherm (AI) analysis in describing mineral-water interface reactions such as radionuclide sorption onto (hydr) oxides and clays. Any site-binding SCM based on the mole balance of surface sites, in fact, reproduces the (competitive) Langmuir isotherm, optionally amended with electrostatic Coulomb's non-ideal term. In most SCM implementations, it is difficult to incorporate real-surface phenomena (site heterogeneity, lateral interactions, surface condensation) described in classic AI approaches other than Langmuir's. Thermodynamic relations between SCMs and AIs that remained obscure in the past have been recently clarified using new definitions of standard and reference states of surface species [1,2]. On this basis, a method for separating the Langmuir AI into ideal (linear) and non-ideal parts [2] was applied to multi-dentate Langmuir, Frumkin, and BET isotherms. The aim of this work was to obtain the surface activity coefficient terms that make the SCM site mole balance constraints obsolete and, in this way, extend thermodynamic SCMs to cover sorption phenomena described by the respective AIs. The multi-dentate Langmuir term accounts for the site saturation with n-dentate surface species, as illustrated on modeling bi-dentate U VI complexes on goethite or SiO 2 surfaces. The Frumkin term corrects for the lateral interactions of the mono-dentate surface species; in particular, it has the same form as the Coulombic term of the constant-capacitance EDL combined with the Langmuir term. The BET term (three parameters) accounts for more than a monolayer adsorption up to the surface condensation; it can potentially describe the surface precipitation of nickel and other cations on hydroxides and clay minerals. All three non-ideal terms (in GEM SCMs implementation [1,2]) by now are used for non-competing surface species only. Upon 'surface dilution

  19. Markets for Canadian bitumen-based feedstock

    International Nuclear Information System (INIS)

    Marshall, R.; Lauerman, V.; Yamaguchi, N.

    2001-02-01

    This study was undertaken in an effort to determine the market potential for crude bitumen and derivative products from the Western Canadian Sedimentary Basin in 2007. As part of the study, CERI assessed the economic viability of a wide range of bitumen-based feedstock based on their refining values, investigated the sensitivity of refinery demand to the prices of these feedstocks, and examined the competitiveness of bitumen-based feedstocks and conventional crudes. A US$18.00 per barrel price for West Texas Intermediate at Cushing, Oklahoma, was assumed in all calculations, including other crude prices, as well as for Western Canadian and US crude oil production forecasts. Four different scenarios have been considered, but only the 'most plausible' scenario is discussed in the report. Consequently, Hydrocracked/Aromatics Saturated Synthetic Crude Oil, which is currently only a hypothetical product, is excluded from consideration. The availability of historical price differentials for the various competing crudes was another assumption used in developing the scenario. Proxy prices for the bitumen-based feedstock were based on their respective supply costs. The study concludes that the principal dilemma facing bitumen producers in Western Canada is to determine the amount of upgrading necessary to ensure an economic market for their product in the future. In general, the greater the degree of upgrading, the higher is the demand for bitumen-based feedstock. However, it must be kept in mind that the upgrading decisions of other bitumen producers, along with many other factors, will have a decisive impact on the economics of any individual project. The combination of coking capacity and asphalt demand limits the market for heavy and extra-heavy crudes. As a result, the researchers concluded that major expansion of heavy crude conversion capacity may have to wait until the end of the current decade. The economic market for bitumen-based blends in 2007 is estimated at

  20. Investigation of mouldability for feedstocks used powder injection moulding

    Energy Technology Data Exchange (ETDEWEB)

    Karatas, Cetin [Gazi University, Faculty of Technology, Department of Mechanical Technology, Teknikokullar, 06500 Ankara (Turkey); Soezen, Adnan [Gazi University, Faculty of Technology, Department of Mechanical Technology, Teknikokullar, 06500 Ankara (Turkey)], E-mail: asozen@gazi.edu.tr; Arcaklioglu, Erol [The Scientific and Technological Research Council of Turkey, Tunus Caddesi No. 80 06100 Kavaklidere / Ankara (Turkey); Erguney, Sami [Gazi University, Faculty of Technology, Department of Mechanical Technology, Teknikokullar, 06500 Ankara (Turkey)

    2008-10-15

    In this study performed experimental and theoretical analysis of mouldability for feedstocks used powder injection moulding. This study covers two main subjects: (i) The experimental analysis: The barrel temperature, injection pressure and flow rate are factors for powder injection moulding (PIM). Powder-binder mixture using as feedstock as feedstock in PIM requires a little more attention and sensitivity. Obtaining the balance among with pressure, temperature and especially flow rate are the most important in aspect of undesirable conclusions such as powder-binder separation, sink marks and crack in moulded party structure. In this study; available feed stocks using in PIM were injected in three different cavities which consist of zigzag form, constant cross section and stair form (in five different thicknesses) mouldability them are measured. Because of difference between material and binder measured lengths were different. These were measured as 533 mm, 268 mm, 211 mm and 150 mm in advanced materials trade mark Fe-2Ni, BASF firm Catamould AO-F, FN02, 316L stainless steel, respectively. (ii) The theoretical analysis: The use of artificial neural network (ANN) has been proposed to determine the mouldability for feedstocks using in powder injection moulding using results of experimental analysis. In order to train the neural network, limited experimental measurements were used as training and test data. The best fitting training data set was obtained with three and four neurons in the hidden-layer, which made it possible to predict yield length with accuracy at least as good as that of the experimental error, over the whole experimental range. After training, it was found the R{sup 2} values are 0.999463, 0.999445, 0.999574 and 0.999593for Fe-2Ni, BASF firm Catamould AO-F, FN02, 316L stainless steel, respectively. Similarly, these values for testing data are 0.999129, 0.999666, 0.998612 and 0.997512, respectively. As seen from the results of mathematical modeling

  1. Acceptable contamination levels in solar grade silicon: From feedstock to solar cell

    International Nuclear Information System (INIS)

    Hofstetter, J.; Lelievre, J.F.; Canizo, C.; Luque, A. del

    2009-01-01

    Ultimately, alternative ways of silicon purification for photovoltaic applications are developed and applied. There is an ongoing debate about what are the acceptable contamination levels within the purified silicon feedstock to specify the material as solar grade silicon. Applying a simple model and making some additional assumptions, we calculate the acceptable contamination levels of different characteristic impurities for each fabrication step of a typical industrial mc-Si solar cell. The acceptable impurity concentrations within the finished solar cell are calculated for SRH recombination exclusively and under low injection conditions. It is assumed that during solar cell fabrication impurity concentrations are only altered by a gettering step. During the crystallization process, impurity segregation at the solid-liquid interface and at extended defects are taken into account. Finally, the initial contamination levels allowed within the feedstock are deduced. The acceptable concentration of iron in the finished solar cell is determined to be 9.7x10 -3 ppma whereas the concentration in the silicon feedstock can be as high as 12.5 ppma. In comparison, the titanium concentration admitted in the solar cell is calculated to be 2.7x10 -4 ppma and the allowed concentration of 2.2x10 -2 ppma in the feedstock is only two orders of magnitude higher. Finally, it is shown theoretically and experimentally that slow cooling rates can lead to a decrease of the interstitial Fe concentration and thus relax the purity requirements in the feedstock.

  2. Survey of Alternative Feedstocks for Commodity Chemical Manufacturing

    Energy Technology Data Exchange (ETDEWEB)

    McFarlane, Joanna [ORNL; Robinson, Sharon M [ORNL

    2008-02-01

    The current high prices for petroleum and natural gas have spurred the chemical industry to examine alternative feedstocks for the production of commodity chemicals. High feedstock prices have driven methanol and ammonia production offshore. The U.S. Chemical Industry is the largest user of natural gas in the country. Over the last 30 years, alternatives to conventional petroleum and natural gas feedstocks have been developed, but have limited, if any, commercial implementation in the United States. Alternative feedstocks under consideration include coal from unconventional processing technologies, such as gasification and liquefaction, novel resources such as biomass, stranded natural gas from unconventional reserves, and heavy oil from tar sands or oil shale. These feedstock sources have been evaluated with respect to the feasibility and readiness for production of the highest volume commodity chemicals in the United States. Sources of organic compounds, such as ethanol from sugar fermentation and bitumen-derived heavy crude are now being primarily exploited for fuels, rather than for chemical feedstocks. Overall, government-sponsored research into the use of alternatives to petroleum feedstocks focuses on use for power and transportation fuels rather than for chemical feedstocks. Research is needed to reduce cost and technical risk. Use of alternative feedstocks is more common outside the United States R&D efforts are needed to make these processes more efficient and less risky before becoming more common domestically. The status of alternative feedstock technology is summarized.

  3. Incorporating food web dynamics into ecological restoration: a modeling approach for river ecosystems

    Science.gov (United States)

    J. Ryan Bellmore; Joseph R. Benjamin; Michael Newsom; Jennifer A. Bountry; Daniel Dombroski

    2017-01-01

    Restoration is frequently aimed at the recovery of target species, but also influences the larger food web in which these species participate. Effects of restoration on this broader network of organisms can influence target species both directly and indirectly via changes in energy flow through food webs. To help incorporate these complexities into river restoration...

  4. Incorporation of the radioprotective molecule cysteamine in model membranes: an NMR study

    International Nuclear Information System (INIS)

    Laval, J.D.; Debouzy, J.C.; Fauvelle, F.; Viret, J.; Fatome, M.

    1995-01-01

    The incorporation of the cysteamine molecule in small unilamellar vesicles was studies using proton NMR technics. A linear inclusion of the radioprotective molecule was firstly observed by increasing the Cysteamine/phospholipid molar ratios, followed by a saturation for the highest ratios. Such results may be adapted to a new galenic form study. (authors). 6 refs., 2 figs

  5. 76 FR 66617 - Airworthiness Directives; Erickson Air-Crane Incorporated Model S-64F Helicopters

    Science.gov (United States)

    2011-10-27

    ...-026-AD; Amendment 39-16835; AD 2011-21-12] RIN 2120-AA64 Airworthiness Directives; Erickson Air-Crane.... SUMMARY: We are adopting a new airworthiness directive (AD) for the Erickson Air-Crane (Erickson Air-Crane..., 2011. ADDRESSES: For service information identified in this AD, contact Erickson Air-Crane Incorporated...

  6. Strategies for Incorporating Women-Specific Sexuality Education into Addiction Treatment Models

    Science.gov (United States)

    James, Raven

    2007-01-01

    This paper advocates for the incorporation of a women-specific sexuality curriculum in the addiction treatment process to aid in sexual healing and provide for aftercare issues. Sexuality in addiction treatment modalities is often approached from a sex-negative stance, or that of sexual victimization. Sexual issues are viewed as addictive in and…

  7. Incorporation of oxygen contribution by plant roots into classical dissolved oxygen deficit model for a subsurface flow treatment wetland.

    Science.gov (United States)

    Bezbaruah, Achintya N; Zhang, Tian C

    2009-01-01

    It has been long established that plants play major roles in a treatment wetland. However, the role of plants has not been incorporated into wetland models. This study tries to incorporate wetland plants into a biochemical oxygen demand (BOD) model so that the relative contributions of the aerobic and anaerobic processes to meeting BOD can be quantitatively determined. The classical dissolved oxygen (DO) deficit model has been modified to simulate the DO curve for a field subsurface flow constructed wetland (SFCW) treating municipal wastewater. Sensitivities of model parameters have been analyzed. Based on the model it is predicted that in the SFCW under study about 64% BOD are degraded through aerobic routes and 36% is degraded anaerobically. While not exhaustive, this preliminary work should serve as a pointer for further research in wetland model development and to determine the values of some of the parameters used in the modified DO deficit and associated BOD model. It should be noted that nitrogen cycle and effects of temperature have not been addressed in these models for simplicity of model formulation. This paper should be read with this caveat in mind.

  8. Incorporating creditors' seniority into contingent claim models: Applicarion to peripheral euro area countries

    OpenAIRE

    Gómez-Puig, Marta; Singh, Manish Kumar; Sosvilla Rivero, Simón, 1961-

    2018-01-01

    This paper highlights the role of multilateral creditors (i.e., the ECB, IMF, ESM etc.) and their preferred creditor status in explaining the sovereign default risk of peripheral euro area (EA) countries. Incorporating lessons from sovereign debt crises in general, and from the Greek debt restructuring in particular, we define the priority structure of sovereigns' creditors that is most relevant for peripheral EA countries in severe crisis episodes. This new priority structure of creditors, t...

  9. Preparation of gasification feedstock from leafy biomass.

    Science.gov (United States)

    Shone, C M; Jothi, T J S

    2016-05-01

    Dried leaves are a potential source of energy although these are not commonly used beside to satisfy daily energy demands in rural areas. This paper aims at preparing a leafy biomass feedstock in the form of briquettes which can be directly used for combustion or to extract the combustible gas using a gasifier. Teak (Tectona grandis) and rubber (Hevea brasiliensis) leaves are considered for the present study. A binder-assisted briquetting technique with tapioca starch as binder is adopted. Properties of these leafy biomass briquettes such as moisture content, calorific value, compressive strength, and shatter index are determined. From the study, briquettes with biomass-to-binder ratio of 3:5 are found to be stable. Higher mass percentage of binder is considered for preparation of briquettes due to the fact that leafy biomasses do not adhere well on densification with lower binder content. Ultimate analysis test is conducted to analyze the gasification potential of the briquettes. Results show that the leafy biomass prepared from teak and rubber leaves has calorific values of 17.5 and 17.8 MJ/kg, respectively, which are comparable with those of existing biomass feedstock made of sawdust, rice husk, and rice straw.

  10. Shorea robusta: A sustainable biomass feedstock

    Directory of Open Access Journals (Sweden)

    Vishal Kumar Singh

    2016-09-01

    Full Text Available The biomass feedstock needs to be available in a manner that is sustainable as well as renewable. However, obtaining reliable and cost effective supplies of biomass feedstock produced in a sustainable manner can prove to be difficult. Traditional biomass, mainly in the form of fallen leaves, fuel wood or dried dung, has long been the renewable and sustainable energy source for cooking and heating. Present study accounts for the biomass of fallen leaves of Shorea robusta, also known as sal, sakhua or shala tree, in the campus of BIT Mesra (Ranchi. These leaves are being gathered and burnt rather than being sold commercially. They contain water to varying degrees which affects their energy content. Hence, measurement of moisture content is critical for its biomass assessment. The leaves were collected, weighed, oven dried at 100oC until constant weight, then dry sample was reweighed to calculate the moisture content that has been driven off. By subtraction of moisture content from the initial weight of leaves, biomass was calculated. Using Differential Scanning Calorimeter (DSC the heat content of the leaves was calculated and the elemental analysis of leaf was done by CHNSO elemental analyser. Further, total biomass and carbon content of Sal tree was calculated using allometric equations so as to make a comparison to the biomass stored in dried fallen leaves

  11. Ecotoxicological characterization of biochars: role of feedstock and pyrolysis temperature.

    Science.gov (United States)

    Domene, X; Enders, A; Hanley, K; Lehmann, J

    2015-04-15

    Seven contrasting feedstocks were subjected to slow pyrolysis at low (300 or 350°C) and high temperature (550 or 600°C), and both biochars and the corresponding feedstocks tested for short-term ecotoxicity using basal soil respiration and collembolan reproduction tests. After a 28-d incubation, soil basal respiration was not inhibited but stimulated by additions of feedstocks and biochars. However, variation in soil respiration was dependent on both feedstock and pyrolysis temperature. In the last case, respiration decreased with pyrolysis temperature (r=-0.78; pcharacterization schemes or in management recommendations. Copyright © 2014 Elsevier B.V. All rights reserved.

  12. A mathematical model to determine incorporated quantities of radioactivity from the measured photometric values of tritium-autoradiographs in neuroanatomy

    International Nuclear Information System (INIS)

    Jennissen, J.J.

    1981-01-01

    The mathematical/empirical model developed in this paper helps to determine the incorporated radioactivity from the measured photometric values and the exposure time T. Possible errors of autoradiography due to the exposure time or the preparation are taken into consideration by the empirical model. It is shown that the error of appr. 400% appearing in the sole comparison of the measured photometric values can be corrected. The model is valid for neuroanatomy as optical nerves, i.e. neuroanatomical material, were used to develop it. Its application also to the other sections of the central nervous system seems to be justified due to the reduction of errors thus achieved. (orig.) [de

  13. Breeding Energy Cane Cultivars as a Biomass Feedstock for Coal Replacement

    Science.gov (United States)

    Research and advanced breeding have demonstrated that energy cane possesses all of the attributes desirable in a biofuel feedstock: extremely good biomass yield in a small farming footprint; negative/neutral carbon footprint; maximum outputs from minimum inputs; well-established growing model for fa...

  14. Incorporating wind availability into land use regression modelling of air quality in mountainous high-density urban environment.

    Science.gov (United States)

    Shi, Yuan; Lau, Kevin Ka-Lun; Ng, Edward

    2017-08-01

    Urban air quality serves as an important function of the quality of urban life. Land use regression (LUR) modelling of air quality is essential for conducting health impacts assessment but more challenging in mountainous high-density urban scenario due to the complexities of the urban environment. In this study, a total of 21 LUR models are developed for seven kinds of air pollutants (gaseous air pollutants CO, NO 2 , NO x , O 3 , SO 2 and particulate air pollutants PM 2.5 , PM 10 ) with reference to three different time periods (summertime, wintertime and annual average of 5-year long-term hourly monitoring data from local air quality monitoring network) in Hong Kong. Under the mountainous high-density urban scenario, we improved the traditional LUR modelling method by incorporating wind availability information into LUR modelling based on surface geomorphometrical analysis. As a result, 269 independent variables were examined to develop the LUR models by using the "ADDRESS" independent variable selection method and stepwise multiple linear regression (MLR). Cross validation has been performed for each resultant model. The results show that wind-related variables are included in most of the resultant models as statistically significant independent variables. Compared with the traditional method, a maximum increase of 20% was achieved in the prediction performance of annual averaged NO 2 concentration level by incorporating wind-related variables into LUR model development. Copyright © 2017 Elsevier Inc. All rights reserved.

  15. A computational model incorporating neural stem cell dynamics reproduces glioma incidence across the lifespan in the human population.

    Directory of Open Access Journals (Sweden)

    Roman Bauer

    Full Text Available Glioma is the most common form of primary brain tumor. Demographically, the risk of occurrence increases until old age. Here we present a novel computational model to reproduce the probability of glioma incidence across the lifespan. Previous mathematical models explaining glioma incidence are framed in a rather abstract way, and do not directly relate to empirical findings. To decrease this gap between theory and experimental observations, we incorporate recent data on cellular and molecular factors underlying gliomagenesis. Since evidence implicates the adult neural stem cell as the likely cell-of-origin of glioma, we have incorporated empirically-determined estimates of neural stem cell number, cell division rate, mutation rate and oncogenic potential into our model. We demonstrate that our model yields results which match actual demographic data in the human population. In particular, this model accounts for the observed peak incidence of glioma at approximately 80 years of age, without the need to assert differential susceptibility throughout the population. Overall, our model supports the hypothesis that glioma is caused by randomly-occurring oncogenic mutations within the neural stem cell population. Based on this model, we assess the influence of the (experimentally indicated decrease in the number of neural stem cells and increase of cell division rate during aging. Our model provides multiple testable predictions, and suggests that different temporal sequences of oncogenic mutations can lead to tumorigenesis. Finally, we conclude that four or five oncogenic mutations are sufficient for the formation of glioma.

  16. Incorporating regime metrics into latent variable dynamic models to detect early-warning signals of functional changes in fisheries ecology

    OpenAIRE

    Trifonova, N; Duplisea, D; Kenny, A; Maxwell, D; Tucker, A

    2014-01-01

    In this study, dynamic Bayesian networks have been applied to predict future biomass of geographically different but functionally equivalent fish species. A latent variable is incorporated to model functional collapse, where the underlying food web structure dramatically changes irrevocably (known as a regime shift). We examined if the use of a hidden variable can reflect changes in the trophic dynamics of the system and also whether the inclusion of recognised statistical metrics would impro...

  17. Anticipating potential biodiversity conflicts for future biofuel crops in South Africa: Incorporating land cover information with Species Distribution Models

    CSIR Research Space (South Africa)

    Blanchard, R

    2012-10-01

    Full Text Available % of biodiversity importance. Anticipating potential biodiversity confl icts for future biofuel crops in South Africa: Incorporating land cover information with Species Distribution Models R BLANCHARD1, DR P O?FARRELL1 AND PROF. D RICHARDSON2 1CSIR Natural... Resources and the Environment, PO Box 320, Stellenbosch, 7599, South Africa 2Centre for Invasion Biology, Department of Botany and Zoology, Stellenbosch University, Private Bag X1, Matieland 7602, South Africa Email: rblanchard@csir.co.za ? www...

  18. Incorporating environmental attitudes in discrete choice models: an exploration of the utility of the awareness of consequences scale.

    Science.gov (United States)

    Hoyos, David; Mariel, Petr; Hess, Stephane

    2015-02-01

    Environmental economists are increasingly interested in better understanding how people cognitively organise their beliefs and attitudes towards environmental change in order to identify key motives and barriers that stimulate or prevent action. In this paper, we explore the utility of a commonly used psychometric scale, the awareness of consequences (AC) scale, in order to better understand stated choices. The main contribution of the paper is that it provides a novel approach to incorporate attitudinal information into discrete choice models for environmental valuation: firstly, environmental attitudes are incorporated using a reinterpretation of the classical AC scale recently proposed by Ryan and Spash (2012); and, secondly, attitudinal data is incorporated as latent variables under a hybrid choice modelling framework. This novel approach is applied to data from a survey conducted in the Basque Country (Spain) in 2008 aimed at valuing land-use policies in a Natura 2000 Network site. The results are relevant to policy-making because choice models that are able to accommodate underlying environmental attitudes may help in designing more effective environmental policies. Copyright © 2014 Elsevier B.V. All rights reserved.

  19. [Incorporation of an organic MAGIC (Model of Acidification of Groundwater in Catchments) and testing of the revised model using independent data sources]. [MAGIC Model

    Energy Technology Data Exchange (ETDEWEB)

    Sullivan, T.J.

    1992-09-01

    A project was initiated in March, 1992 to (1) incorporate a rigorous organic acid representation, based on empirical data and geochemical considerations, into the MAGIC model of acidification response, and (2) test the revised model using three sets of independent data. After six months of performance, the project is on schedule and the majority of the tasks outlined for Year 1 have been successfully completed. Major accomplishments to data include development of the organic acid modeling approach, using data from the Adirondack Lakes Survey Corporation (ALSC), and coupling the organic acid model with MAGIC for chemical hindcast comparisons. The incorporation of an organic acid representation into MAGIC can account for much of the discrepancy earlier observed between MAGIC hindcasts and paleolimnological reconstructions of preindustrial pH and alkalinity for 33 statistically-selected Adirondack lakes. Additional work is on-going for model calibration and testing with data from two whole-catchment artificial acidification projects. Results obtained thus far are being prepared as manuscripts for submission to the peer-reviewed scientific literature.

  20. Bio-energy feedstock yields and their water quality benefits in Mississippi

    Energy Technology Data Exchange (ETDEWEB)

    Parajuli, Prem B.

    2011-08-10

    Cellulosic and agricultural bio-energy crops can, under careful management, be harvested as feedstock for bio-fuels production and provide environmental benefits. However, it is required to quantify their relative advantages in feedstock production and water quality. The primary objective of this research was to evaluate potential feedstock yield and water quality benefit scenarios of bioenergy crops: Miscanthus (Miscanthus-giganteus), Switchgrass (Panicum virgatum), Johnsongrass (Sorghum halepense), Alfalfa (Medicago sativa L.), Soybean {Glycine max (L.) Merr.}, and Corn (Lea mays) in the Upper Pearl River watershed (UPRW), Mississippi using a Soil and Water Assessment Tool (SWAT). The SWAT model was calibrated (January 1981 to December 1994) and validated (January 1995 to September 2008) using monthly measured stream flow data. The calibrated and validated model determined good to very good performance for stream flow prediction (R2 and E from 0.60 to 0.86). The RMSE values (from 14 m3 s-1 to 37 m3 s-1) were estimated at similar levels of errors during model calibration and validation. The long-term average annual potential feedstock yield as an alternative energy source was determined the greatest when growing Miscanthus grass (373,849 Mg) as followed by Alfalfa (206,077 Mg), Switchgrass (132,077 Mg), Johnsongrass (47,576 Mg), Soybean (37,814 Mg), and Corn (22,069 Mg) in the pastureland and cropland of the watershed. Model results determined that average annual sediment yield from the Miscanthus grass scenario determined the least (1.16 Mg/ha) and corn scenario the greatest (12.04 Mg/ha). The SWAT model simulated results suggested that growing Miscanthus grass in the UPRW would have the greatest potential feedstock yield and water quality benefits.

  1. Incorporating population viability models into species status assessment and listing decisions under the U.S. Endangered Species Act

    Directory of Open Access Journals (Sweden)

    Conor P. McGowan

    2017-10-01

    Full Text Available Assessment of a species' status is a key part of management decision making for endangered and threatened species under the U.S. Endangered Species Act. Predicting the future state of the species is an essential part of species status assessment, and projection models can play an important role in developing predictions. We built a stochastic simulation model that incorporated parametric and environmental uncertainty to predict the probable future status of the Sonoran desert tortoise in the southwestern United States and North Central Mexico. Sonoran desert tortoise was a Candidate species for listing under the Endangered Species Act, and decision makers wanted to use model predictions in their decision making process. The model accounted for future habitat loss and possible effects of climate change induced droughts to predict future population growth rates, abundances, and quasi-extinction probabilities. Our model predicts that the population will likely decline over the next few decades, but there is very low probability of quasi-extinction less than 75 years into the future. Increases in drought frequency and intensity may increase extinction risk for the species. Our model helped decision makers predict and characterize uncertainty about the future status of the species in their listing decision. We incorporated complex ecological processes (e.g., climate change effects on tortoises in transparent and explicit ways tailored to support decision making processes related to endangered species.

  2. Incorporating variability in simulations of seasonally forced phenology using integral projection models.

    Science.gov (United States)

    Goodsman, Devin W; Aukema, Brian H; McDowell, Nate G; Middleton, Richard S; Xu, Chonggang

    2018-01-01

    Phenology models are becoming increasingly important tools to accurately predict how climate change will impact the life histories of organisms. We propose a class of integral projection phenology models derived from stochastic individual-based models of insect development and demography. Our derivation, which is based on the rate summation concept, produces integral projection models that capture the effect of phenotypic rate variability on insect phenology, but which are typically more computationally frugal than equivalent individual-based phenology models. We demonstrate our approach using a temperature-dependent model of the demography of the mountain pine beetle ( Dendroctonus ponderosae Hopkins), an insect that kills mature pine trees. This work illustrates how a wide range of stochastic phenology models can be reformulated as integral projection models. Due to their computational efficiency, these integral projection models are suitable for deployment in large-scale simulations, such as studies of altered pest distributions under climate change.

  3. Biodiesel from non-food alternative feed-stock

    Science.gov (United States)

    As a potential feedstock for biodiesel (BD) production, Jojoba oil was extracted from Jojoba (Simmondsia chinensis L.) plant seeds that contained around 50-60 wt.%, which were explored as non-food alternative feedstocks. Interestingly, Jojoba oil has long-chain wax esters and is not a typical trigly...

  4. Assessment of coal liquids as refinery feedstocks

    Energy Technology Data Exchange (ETDEWEB)

    Zhou, P.

    1992-02-01

    The R&D of direct coal liquefaction has reached such a stage that current two-stage processes can produce coal liquids with high yields and improved quality at a reasonable cost. To fully realize the potential value, these coal liquids should be refined into high-value liquid transportation fuels. The purpose of this study is to assess coal liquids as feedstocks to be processed by modern petroleum refining technologies. After the introduction, Section 2.0 summarizes ASTM specifications for major transportation fuels: gasoline, jet fuel, and diesel fuel, which serve as a target for coal-liquid refining. A concise description of modern refining processes follows with an emphasis on the requirements for the raw materials. These provide criteria to judge the quality of coal liquids as a refinery feedstock for the production of marketable liquid fuels. Section 3.0 surveys the properties of coal liquids produced by various liquefaction processes. Compared with typical petroleum oils, the current two-stage coal liquids are: Light in boiling range and free of resids and metals; very low in sulfur but relatively high in oxygen; relatively low in hydrogen and high in cyclics content; and essentially toxicologically inactive when end point is lower than 650{degrees}F, particularly after hydroprocessing. Despite these characteristics, the coal liquids are basically similar to petroleum. The modern refining technology is capable of processing coal liquids into transportation fuels meeting all specifications, and hydroprocessinq is obviously the major tool. The important point is the determination of a reasonable product slate and an appropriate refining scheme.

  5. Assessment of coal liquids as refinery feedstocks

    Energy Technology Data Exchange (ETDEWEB)

    Zhou, P.

    1992-02-01

    The R D of direct coal liquefaction has reached such a stage that current two-stage processes can produce coal liquids with high yields and improved quality at a reasonable cost. To fully realize the potential value, these coal liquids should be refined into high-value liquid transportation fuels. The purpose of this study is to assess coal liquids as feedstocks to be processed by modern petroleum refining technologies. After the introduction, Section 2.0 summarizes ASTM specifications for major transportation fuels: gasoline, jet fuel, and diesel fuel, which serve as a target for coal-liquid refining. A concise description of modern refining processes follows with an emphasis on the requirements for the raw materials. These provide criteria to judge the quality of coal liquids as a refinery feedstock for the production of marketable liquid fuels. Section 3.0 surveys the properties of coal liquids produced by various liquefaction processes. Compared with typical petroleum oils, the current two-stage coal liquids are: Light in boiling range and free of resids and metals; very low in sulfur but relatively high in oxygen; relatively low in hydrogen and high in cyclics content; and essentially toxicologically inactive when end point is lower than 650[degrees]F, particularly after hydroprocessing. Despite these characteristics, the coal liquids are basically similar to petroleum. The modern refining technology is capable of processing coal liquids into transportation fuels meeting all specifications, and hydroprocessinq is obviously the major tool. The important point is the determination of a reasonable product slate and an appropriate refining scheme.

  6. Incorporating microbial dormancy dynamics into soil decomposition models to improve quantification of soil carbon dynamics of northern temperate forests

    Science.gov (United States)

    He, Yujie; Yang, Jinyan; Zhuang, Qianlai; Harden, Jennifer W.; McGuire, A. David; Liu, Yaling; Wang, Gangsheng; Gu, Lianhong

    2015-01-01

    Soil carbon dynamics of terrestrial ecosystems play a significant role in the global carbon cycle. Microbial-based decomposition models have seen much growth recently for quantifying this role, yet dormancy as a common strategy used by microorganisms has not usually been represented and tested in these models against field observations. Here we developed an explicit microbial-enzyme decomposition model and examined model performance with and without representation of microbial dormancy at six temperate forest sites of different forest types. We then extrapolated the model to global temperate forest ecosystems to investigate biogeochemical controls on soil heterotrophic respiration and microbial dormancy dynamics at different temporal-spatial scales. The dormancy model consistently produced better match with field-observed heterotrophic soil CO2 efflux (RH) than the no dormancy model. Our regional modeling results further indicated that models with dormancy were able to produce more realistic magnitude of microbial biomass (dormancy, our modeling results showed that soil carbon-to-nitrogen ratio (C:N) was a major regulating factor at regional scales (correlation coefficient = −0.43 to −0.58), indicating scale-dependent biogeochemical controls on microbial dynamics. Our findings suggest that incorporating microbial dormancy could improve the realism of microbial-based decomposition models and enhance the integration of soil experiments and mechanistically based modeling.

  7. Simplex network modeling for press-molded ceramic bodies incorporated with granite waste

    International Nuclear Information System (INIS)

    Pedroti, L.G.; Vieira, C.M.F.; Alexandre, J.; Monteiro, S.N.; Xavier, G.C.

    2012-01-01

    Extrusion of a clay body is the most commonly applied process in the ceramic industries for manufacturing structural block. Nowadays, the assembly of such blocks through a fitting system that facilitates the final mounting is gaining attention owing to the saving in material and reducing in the cost of the building construction. In this work, the ideal composition of clay bodies incorporated with granite powder waste was investigated for the production of press-molded ceramic blocks. An experimental design was applied to determine the optimum properties and microstructures involving not only the precursors compositions but also the press and temperature conditions. Press load from 15 ton and temperatures from 850 to 1050°C were considered. The results indicated that varying mechanical strength of 2 MPa to 20 MPa and varying water absorption of 19% to 30%. (author)

  8. Incorporation of a Generalized Data Assimilation Module within a Global Photospheric Flux Transport Model

    Science.gov (United States)

    2016-03-31

    Table of Contents 1. INTRODUCTION...Traditional Photospheric Magnetic Flux Synoptic Maps .........................................................1 2.2 Photospheric Flux Transport Models...4 3. WH model evolved synoptic map (latitude vs. longitude

  9. Incorporating Pass-Phrase Dependent Background Models for Text-Dependent Speaker Verification

    OpenAIRE

    Sarkar, A. K.; Tan, Zheng-Hua

    2016-01-01

    In this paper, we propose pass-phrase dependent background models (PBMs) for text-dependent (TD) speaker verification (SV) to integrate the pass-phrase identification process into the conventional TD-SV system, where a PBM is derived from a text-independent background model through adaptation using the utterances of a particular pass-phrase. During training, pass-phrase specific target speaker models are derived from the particular PBM using the training data for the respective target model. ...

  10. A Mass Balance Model for Designing Green Roof Systems that Incorporate a Cistern for Re-Use

    Directory of Open Access Journals (Sweden)

    Manoj Chopra

    2012-11-01

    Full Text Available Green roofs, which have been used for several decades in many parts of the world, offer a unique and sustainable approach to stormwater management. Within this paper, evidence is presented on water retention for an irrigated green roof system. The presented green roof design results in a water retention volume on site. A first principle mass balance computer model is introduced to assist with the design of these green roof systems which incorporate a cistern to capture and reuse runoff waters for irrigation of the green roof. The model is used to estimate yearly stormwater retention volume for different cistern storage volumes. Additionally, the Blaney and Criddle equation is evaluated for estimation of monthly evapotranspiration rates for irrigated systems and incorporated into the model. This is done so evapotranspiration rates can be calculated for regions where historical data does not exist, allowing the model to be used anywhere historical weather data are available. This model is developed and discussed within this paper as well as compared to experimental results.

  11. Using stochastic models to incorporate spatial and temporal variability [Exercise 14

    Science.gov (United States)

    Carolyn Hull Sieg; Rudy M. King; Fred Van Dyke

    2003-01-01

    To this point, our analysis of population processes and viability in the western prairie fringed orchid has used only deterministic models. In this exercise, we conduct a similar analysis, using a stochastic model instead. This distinction is of great importance to population biology in general and to conservation biology in particular. In deterministic models,...

  12. Investigation of a growth model incorporating density dependence for the mackerel management plan simulations

    NARCIS (Netherlands)

    Brunel, T.P.A.

    2015-01-01

    This report presents a framework to model density dependent growth for the North East Atlantic mackerel. The model used is the classical von Bertalanffy equation, but modified so that growth is reduced when stock size increases. The model developed was able to reproduce quite closely the trends in

  13. Cryogenic homogenization and sampling of heterogeneous multi-phase feedstock

    Science.gov (United States)

    Doyle, Glenn Michael; Ideker, Virgene Linda; Siegwarth, James David

    2002-01-01

    An apparatus and process for producing a homogeneous analytical sample from a heterogenous feedstock by: providing the mixed feedstock, reducing the temperature of the feedstock to a temperature below a critical temperature, reducing the size of the feedstock components, blending the reduced size feedstock to form a homogeneous mixture; and obtaining a representative sample of the homogeneous mixture. The size reduction and blending steps are performed at temperatures below the critical temperature in order to retain organic compounds in the form of solvents, oils, or liquids that may be adsorbed onto or absorbed into the solid components of the mixture, while also improving the efficiency of the size reduction. Preferably, the critical temperature is less than 77 K (-196.degree. C.). Further, with the process of this invention the representative sample may be maintained below the critical temperature until being analyzed.

  14. The watershed-scale optimized and rearranged landscape design (WORLD) model and local biomass processing depots for sustainable biofuel production: Integrated life cycle assessments

    Energy Technology Data Exchange (ETDEWEB)

    Eranki, Pragnya L.; Manowitz, David H.; Bals, Bryan D.; Izaurralde, Roberto C.; Kim, Seungdo; Dale, Bruce E.

    2013-07-23

    An array of feedstock is being evaluated as potential raw material for cellulosic biofuel production. Thorough assessments are required in regional landscape settings before these feedstocks can be cultivated and sustainable management practices can be implemented. On the processing side, a potential solution to the logistical challenges of large biorefi neries is provided by a network of distributed processing facilities called local biomass processing depots. A large-scale cellulosic ethanol industry is likely to emerge soon in the United States. We have the opportunity to influence the sustainability of this emerging industry. The watershed-scale optimized and rearranged landscape design (WORLD) model estimates land allocations for different cellulosic feedstocks at biorefinery scale without displacing current animal nutrition requirements. This model also incorporates a network of the aforementioned depots. An integrated life cycle assessment is then conducted over the unified system of optimized feedstock production, processing, and associated transport operations to evaluate net energy yields (NEYs) and environmental impacts.

  15. Incorporating shape constraints in generalized additive modelling of the height-diameter relationship for Norway spruce

    Directory of Open Access Journals (Sweden)

    Natalya Pya

    2016-02-01

    Full Text Available Background: Measurements of tree heights and diameters are essential in forest assessment and modelling. Tree heights are used for estimating timber volume, site index and other important variables related to forest growth and yield, succession and carbon budget models. However, the diameter at breast height (dbh can be more accurately obtained and at lower cost, than total tree height. Hence, generalized height-diameter (h-d models that predict tree height from dbh, age and other covariates are needed. For a more flexible but biologically plausible estimation of covariate effects we use shape constrained generalized additive models as an extension of existing h-d model approaches. We use causal site parameters such as index of aridity to enhance the generality and causality of the models and to enable predictions under projected changeable climatic conditions. Methods: We develop unconstrained generalized additive models (GAM and shape constrained generalized additive models (SCAM for investigating the possible effects of tree-specific parameters such as tree age, relative diameter at breast height, and site-specific parameters such as index of aridity and sum of daily mean temperature during vegetation period, on the h-d relationship of forests in Lower Saxony, Germany. Results: Some of the derived effects, e.g. effects of age, index of aridity and sum of daily mean temperature have significantly non-linear pattern. The need for using SCAM results from the fact that some of the model effects show partially implausible patterns especially at the boundaries of data ranges. The derived model predicts monotonically increasing levels of tree height with increasing age and temperature sum and decreasing aridity and social rank of a tree within a stand. The definition of constraints leads only to marginal or minor decline in the model statistics like AIC. An observed structured spatial trend in tree height is modelled via 2-dimensional surface

  16. Integrative modelling of animal movement: incorporating in situ habitat and behavioural information for a migratory marine predator.

    Science.gov (United States)

    Bestley, Sophie; Jonsen, Ian D; Hindell, Mark A; Guinet, Christophe; Charrassin, Jean-Benoît

    2013-01-07

    A fundamental goal in animal ecology is to quantify how environmental (and other) factors influence individual movement, as this is key to understanding responsiveness of populations to future change. However, quantitative interpretation of individual-based telemetry data is hampered by the complexity of, and error within, these multi-dimensional data. Here, we present an integrative hierarchical Bayesian state-space modelling approach where, for the first time, the mechanistic process model for the movement state of animals directly incorporates both environmental and other behavioural information, and observation and process model parameters are estimated within a single model. When applied to a migratory marine predator, the southern elephant seal (Mirounga leonina), we find the switch from directed to resident movement state was associated with colder water temperatures, relatively short dive bottom time and rapid descent rates. The approach presented here can have widespread utility for quantifying movement-behaviour (diving or other)-environment relationships across species and systems.

  17. A mathematical model for maximizing the value of phase 3 drug development portfolios incorporating budget constraints and risk.

    Science.gov (United States)

    Patel, Nitin R; Ankolekar, Suresh; Antonijevic, Zoran; Rajicic, Natasa

    2013-05-10

    We describe a value-driven approach to optimizing pharmaceutical portfolios. Our approach incorporates inputs from research and development and commercial functions by simultaneously addressing internal and external factors. This approach differentiates itself from current practices in that it recognizes the impact of study design parameters, sample size in particular, on the portfolio value. We develop an integer programming (IP) model as the basis for Bayesian decision analysis to optimize phase 3 development portfolios using expected net present value as the criterion. We show how this framework can be used to determine optimal sample sizes and trial schedules to maximize the value of a portfolio under budget constraints. We then illustrate the remarkable flexibility of the IP model to answer a variety of 'what-if' questions that reflect situations that arise in practice. We extend the IP model to a stochastic IP model to incorporate uncertainty in the availability of drugs from earlier development phases for phase 3 development in the future. We show how to use stochastic IP to re-optimize the portfolio development strategy over time as new information accumulates and budget changes occur. Copyright © 2013 John Wiley & Sons, Ltd.

  18. Group spike-and-slab lasso generalized linear models for disease prediction and associated genes detection by incorporating pathway information.

    Science.gov (United States)

    Tang, Zaixiang; Shen, Yueping; Li, Yan; Zhang, Xinyan; Wen, Jia; Qian, Chen'ao; Zhuang, Wenzhuo; Shi, Xinghua; Yi, Nengjun

    2018-03-15

    Large-scale molecular data have been increasingly used as an important resource for prognostic prediction of diseases and detection of associated genes. However, standard approaches for omics data analysis ignore the group structure among genes encoded in functional relationships or pathway information. We propose new Bayesian hierarchical generalized linear models, called group spike-and-slab lasso GLMs, for predicting disease outcomes and detecting associated genes by incorporating large-scale molecular data and group structures. The proposed model employs a mixture double-exponential prior for coefficients that induces self-adaptive shrinkage amount on different coefficients. The group information is incorporated into the model by setting group-specific parameters. We have developed a fast and stable deterministic algorithm to fit the proposed hierarchal GLMs, which can perform variable selection within groups. We assess the performance of the proposed method on several simulated scenarios, by varying the overlap among groups, group size, number of non-null groups, and the correlation within group. Compared with existing methods, the proposed method provides not only more accurate estimates of the parameters but also better prediction. We further demonstrate the application of the proposed procedure on three cancer datasets by utilizing pathway structures of genes. Our results show that the proposed method generates powerful models for predicting disease outcomes and detecting associated genes. The methods have been implemented in a freely available R package BhGLM (http://www.ssg.uab.edu/bhglm/). nyi@uab.edu. Supplementary data are available at Bioinformatics online.

  19. Incorporation of Satellite Data and Uncertainty in a Nationwide Groundwater Recharge Model in New Zealand

    Directory of Open Access Journals (Sweden)

    Rogier Westerhoff

    2018-01-01

    Full Text Available A nationwide model of groundwater recharge for New Zealand (NGRM, as described in this paper, demonstrated the benefits of satellite data and global models to improve the spatial definition of recharge and the estimation of recharge uncertainty. NGRM was inspired by the global-scale WaterGAP model but with the key development of rainfall recharge calculation on scales relevant to national- and catchment-scale studies (i.e., a 1 km × 1 km cell size and a monthly timestep in the period 2000–2014 provided by satellite data (i.e., MODIS-derived evapotranspiration, AET and vegetation in combination with national datasets of rainfall, elevation, soil and geology. The resulting nationwide model calculates groundwater recharge estimates, including their uncertainty, consistent across the country, which makes the model unique compared to all other New Zealand estimates targeted towards groundwater recharge. At the national scale, NGRM estimated an average recharge of 2500 m 3 /s, or 298 mm/year, with a model uncertainty of 17%. Those results were similar to the WaterGAP model, but the improved input data resulted in better spatial characteristics of recharge estimates. Multiple uncertainty analyses led to these main conclusions: the NGRM model could give valuable initial estimates in data-sparse areas, since it compared well to most ground-observed lysimeter data and local recharge models; and the nationwide input data of rainfall and geology caused the largest uncertainty in the model equation, which revealed that the satellite data could improve spatial characteristics without significantly increasing the uncertainty. Clearly the increasing volume and availability of large-scale satellite data is creating more opportunities for the application of national-scale models at the catchment, and smaller, scales. This should result in improved utility of these models including provision of initial estimates in data-sparse areas. Topics for future

  20. Effects of transport model alternatives incorporating precipitation on the performance of engineered barriers

    International Nuclear Information System (INIS)

    Ohi, Takao; Miyahara, Kaname; Naito, Morimasa

    1996-01-01

    The migration of radionuclide through bentonite was analyzed by alternative models considering the precipitation caused by decay-chain ingrowth. In the realistic model, the temporal and spacial isotopic ratio in bentonite was taken into account for determining the shared solubility for each radionuclide. The release rate of radionuclide from the outer surface of bentonite to surrounding rock is generally lower in such realistic analysis considering precipitation in bentonite than calculated by the model neglecting precipitation. This result shows the model not considering such effects is mostly conservative for the safety assessment

  1. Incorporating Latent Variables into Discrete Choice Models - A Simultaneous Estimation Approach Using SEM Software

    Directory of Open Access Journals (Sweden)

    Dirk Temme

    2008-12-01

    Full Text Available Integrated choice and latent variable (ICLV models represent a promising new class of models which merge classic choice models with the structural equation approach (SEM for latent variables. Despite their conceptual appeal, applications of ICLV models in marketing remain rare. We extend previous ICLV applications by first estimating a multinomial choice model and, second, by estimating hierarchical relations between latent variables. An empirical study on travel mode choice clearly demonstrates the value of ICLV models to enhance the understanding of choice processes. In addition to the usually studied directly observable variables such as travel time, we show how abstract motivations such as power and hedonism as well as attitudes such as a desire for flexibility impact on travel mode choice. Furthermore, we show that it is possible to estimate such a complex ICLV model with the widely available structural equation modeling package Mplus. This finding is likely to encourage more widespread application of this appealing model class in the marketing field.

  2. Laboratory Testing, Characterization and Mathematical Modeling of the Moniwrist III by Ross-Hime Designs, Incorporated

    National Research Council Canada - National Science Library

    Skormin, Victor A

    2005-01-01

    .... It is proposed to enhance the system performance through development of an optimal comptroller extending the conventional state-variable and model reference control laws, with dynamic programming...

  3. The Internal/External Frame of Reference Model Revisited: Incorporating General Cognitive Ability and General Academic Self-Concept.

    Science.gov (United States)

    Brunner, Martin; Lüdtke, Oliver; Trautwein, Ulrich

    2008-01-01

    The internal/external frame of reference model (I/E model; Marsh, 1986 ) is a highly influential model of self-concept formation, which predicts that domain-specific abilities have positive effects on academic self-concepts in the corresponding domain and negative effects across domains. Investigations of the I/E model do not typically incorporate general cognitive ability or general academic self-concept. This article investigates alternative measurement models for domain-specific and domain-general cognitive abilities and academic self-concepts within an extended I/E model framework using representative data from 25,301 9th-grade students. Empirical support was found for the external validity of a new measurement model for academic self-concepts with respect to key student characteristics (gender, school satisfaction, educational aspirations, domain-specific interests, grades). Moreover, the basic predictions of the I/E model were confirmed, and the new extension of the traditional I/E model permitted meaningful relations to be drawn between domain-general cognitive ability and domain-general academic self-concept as well as between the domain-specific elements of the model.

  4. Methods for determination of biomethane potential of feedstocks: a review

    Directory of Open Access Journals (Sweden)

    Raphael Muzondiwa Jingura

    2017-06-01

    Full Text Available Biogas produced during anaerobic digestion (AD of biodegradable organic materials. AD is a series of biochemical reactions in which microorganisms degrade organic matter under anaerobic conditions. There are many biomass resources that can be degraded by AD to produce biogas. Biogas consists of methane, carbon dioxide, and trace amounts of other gases. The gamut of feedstocks used in AD includes animal manure, municipal solid waste, sewage sludge, and various crops. Several factors affect the potential of feedstocks for biomethane production. The factors include nutrient content, total and volatile solids (VS content, chemical and biological oxygen demand, carbon/nitrogen ratio, and presence of inhibitory substances. The biochemical methane potential (BMP, often defined as the maximum volume of methane produced per g of VS substrate provides an indication of the biodegradability of a substrate and its potential to produce methane via AD. The BMP test is a method of establishing a baseline for performance of AD. BMP data are useful for designing AD parameters in order to optimise methane production. Several methods which include experimental and theoretical methods can be used to determine BMP. The objective of this paper is to review several methods with a special focus on their advantages and disadvantages. The review shows that experimental methods, mainly the BMP test are widely used. The BMP test is credited for its reliability and validity. There are variants of BMP assays as well. Theoretical models are alternative methods to estimate BMP. They are credited for being fast and easy to use. Spectroscopy has emerged as a new experimental tool to determine BMP. Each method has its own advantages and disadvantages with reference to efficacy, time, and ease of use. Choosing a method to use depends on various exigencies. More work needs to be continuously done in order to improve the various methods used to determine BMP.

  5. Using expert knowledge to incorporate uncertainty in cause-of-death assignments for modeling of cause-specific mortality

    Science.gov (United States)

    Walsh, Daniel P.; Norton, Andrew S.; Storm, Daniel J.; Van Deelen, Timothy R.; Heisy, Dennis M.

    2018-01-01

    Implicit and explicit use of expert knowledge to inform ecological analyses is becoming increasingly common because it often represents the sole source of information in many circumstances. Thus, there is a need to develop statistical methods that explicitly incorporate expert knowledge, and can successfully leverage this information while properly accounting for associated uncertainty during analysis. Studies of cause-specific mortality provide an example of implicit use of expert knowledge when causes-of-death are uncertain and assigned based on the observer's knowledge of the most likely cause. To explicitly incorporate this use of expert knowledge and the associated uncertainty, we developed a statistical model for estimating cause-specific mortality using a data augmentation approach within a Bayesian hierarchical framework. Specifically, for each mortality event, we elicited the observer's belief of cause-of-death by having them specify the probability that the death was due to each potential cause. These probabilities were then used as prior predictive values within our framework. This hierarchical framework permitted a simple and rigorous estimation method that was easily modified to include covariate effects and regularizing terms. Although applied to survival analysis, this method can be extended to any event-time analysis with multiple event types, for which there is uncertainty regarding the true outcome. We conducted simulations to determine how our framework compared to traditional approaches that use expert knowledge implicitly and assume that cause-of-death is specified accurately. Simulation results supported the inclusion of observer uncertainty in cause-of-death assignment in modeling of cause-specific mortality to improve model performance and inference. Finally, we applied the statistical model we developed and a traditional method to cause-specific survival data for white-tailed deer, and compared results. We demonstrate that model selection

  6. Incorporating NDVI in a gravity model setting to describe spatio-temporal patterns of Lyme borreliosis incidence

    Science.gov (United States)

    Barrios, J. M.; Verstraeten, W. W.; Farifteh, J.; Maes, P.; Aerts, J. M.; Coppin, P.

    2012-04-01

    Lyme borreliosis (LB) is the most common tick-borne disease in Europe and incidence growth has been reported in several European countries during the last decade. LB is caused by the bacterium Borrelia burgdorferi and the main vector of this pathogen in Europe is the tick Ixodes ricinus. LB incidence and spatial spread is greatly dependent on environmental conditions impacting habitat, demography and trophic interactions of ticks and the wide range of organisms ticks parasite. The landscape configuration is also a major determinant of tick habitat conditions and -very important- of the fashion and intensity of human interaction with vegetated areas, i.e. human exposure to the pathogen. Hence, spatial notions as distance and adjacency between urban and vegetated environments are related to human exposure to tick bites and, thus, to risk. This work tested the adequacy of a gravity model setting to model the observed spatio-temporal pattern of LB as a function of location and size of urban and vegetated areas and the seasonal and annual change in the vegetation dynamics as expressed by MODIS NDVI. Opting for this approach implies an analogy with Newton's law of universal gravitation in which the attraction forces between two bodies are directly proportional to the bodies mass and inversely proportional to distance. Similar implementations have proven useful in fields like trade modeling, health care service planning, disease mapping among other. In our implementation, the size of human settlements and vegetated systems and the distance separating these landscape elements are considered the 'bodies'; and the 'attraction' between them is an indicator of exposure to pathogen. A novel element of this implementation is the incorporation of NDVI to account for the seasonal and annual variation in risk. The importance of incorporating this indicator of vegetation activity resides in the fact that alterations of LB incidence pattern observed the last decade have been ascribed

  7. A rhenium tris-carbonyl derivative as a model molecule for incorporation into phospholipid assemblies for skin applications.

    Science.gov (United States)

    Fernández, Estibalitz; Rodríguez, Gelen; Hostachy, Sarah; Clède, Sylvain; Cócera, Mercedes; Sandt, Christophe; Lambert, François; de la Maza, Alfonso; Policar, Clotilde; López, Olga

    2015-07-01

    A rhenium tris-carbonyl derivative (fac-[Re(CO)3Cl(2-(1-dodecyl-1H-1,2,3,triazol-4-yl)-pyridine)]) was incorporated into phospholipid assemblies, called bicosomes, and the penetration of this molecule into skin was monitored using Fourier-transform infrared microspectroscopy (FTIR). To evaluate the capacity of bicosomes to promote the penetration of this derivative, the skin penetration of the Re(CO)3 derivative dissolved in dimethyl sulfoxide (DMSO), a typical enhancer, was also studied. Dynamic light scattering results (DLS) showed an increase in the size of the bicosomes with the incorporation of the Re(CO)3 derivative, and the FTIR microspectroscopy showed that the Re(CO)3 derivative incorporated in bicosomes penetrated deeper into the skin than when dissolved in DMSO. When this molecule was applied on the skin using the bicosomes, 60% of the Re(CO)3 derivative was retained in the stratum corneum (SC) and 40% reached the epidermis (Epi). Otherwise, the application of this molecule via DMSO resulted in 95% of the Re(CO)3 derivative being in the SC and only 5% reaching the Epi. Using a Re(CO)3 derivative with a dodecyl-chain as a model molecule, it was possible to determine the distribution of molecules with similar physicochemical characteristics in the skin using bicosomes. This fact makes these nanostructures promising vehicles for the application of lipophilic molecules inside the skin. Copyright © 2015 Elsevier B.V. All rights reserved.

  8. Incorporating additional tree and environmental variables in a lodgepole pine stem profile model

    Science.gov (United States)

    John C. Byrne

    1993-01-01

    A new variable-form segmented stem profile model is developed for lodgepole pine (Pinus contorta) trees from the northern Rocky Mountains of the United States. I improved estimates of stem diameter by predicting two of the model coefficients with linear equations using a measure of tree form, defined as a ratio of dbh and total height. Additional improvements were...

  9. Incorporating Response Times in Item Response Theory Models of Reading Comprehension Fluency

    Science.gov (United States)

    Su, Shiyang

    2017-01-01

    With the online assessment becoming mainstream and the recording of response times becoming straightforward, the importance of response times as a measure of psychological constructs has been recognized and the literature of modeling times has been growing during the last few decades. Previous studies have tried to formulate models and theories to…

  10. Approaches to incorporating climate change effects in state and transition simulation models of vegetation

    Science.gov (United States)

    Becky K. Kerns; Miles A. Hemstrom; David Conklin; Gabriel I. Yospin; Bart Johnson; Dominique Bachelet; Scott Bridgham

    2012-01-01

    Understanding landscape vegetation dynamics often involves the use of scientifically-based modeling tools that are capable of testing alternative management scenarios given complex ecological, management, and social conditions. State-and-transition simulation model (STSM) frameworks and software such as PATH and VDDT are commonly used tools that simulate how landscapes...

  11. LINKING MICROBES TO CLIMATE: INCORPORATING MICROBIAL ACTIVITY INTO CLIMATE MODELS COLLOQUIUM

    Energy Technology Data Exchange (ETDEWEB)

    DeLong, Edward; Harwood, Caroline; Reid, Ann

    2011-01-01

    This report explains the connection between microbes and climate, discusses in general terms what modeling is and how it applied to climate, and discusses the need for knowledge in microbial physiology, evolution, and ecology to contribute to the determination of fluxes and rates in climate models. It recommends with a multi-pronged approach to address the gaps.

  12. Building out a Measurement Model to Incorporate Complexities of Testing in the Language Domain

    Science.gov (United States)

    Wilson, Mark; Moore, Stephen

    2011-01-01

    This paper provides a summary of a novel and integrated way to think about the item response models (most often used in measurement applications in social science areas such as psychology, education, and especially testing of various kinds) from the viewpoint of the statistical theory of generalized linear and nonlinear mixed models. In addition,…

  13. Mathematical Modelling in the Junior Secondary Years: An Approach Incorporating Mathematical Technology

    Science.gov (United States)

    Lowe, James; Carter, Merilyn; Cooper, Tom

    2018-01-01

    Mathematical models are conceptual processes that use mathematics to describe, explain, and/or predict the behaviour of complex systems. This article is written for teachers of mathematics in the junior secondary years (including out-of-field teachers of mathematics) who may be unfamiliar with mathematical modelling, to explain the steps involved…

  14. Potential bioethanol feedstock availability around nine locations in the Republic of Ireland

    Energy Technology Data Exchange (ETDEWEB)

    Deverell, R.; McDonnell, K.; Devlin, G. [Department of Biosystems Engineering, Agriculture and Food Science Building, University College Dublin, Belfield (Ireland)

    2009-07-01

    The Republic of Ireland, like many other countries is trying to diversify energy sources to counteract environmental, political and social concerns. Bioethanol from domestically grown agricultural crops is an indigenously produced alternative fuel that can potentially go towards meeting the goal of diversified energy supply. The Republic of Ireland's distribution of existing soils and agricultural land-uses limit arable crop land to around 10% of total agricultural area. Demand for land to produce arable crops is expected to decrease, which could open the opportunity for bioethanol production. Bioethanol production plants are required to be of a sufficient scale in order to compete economically with other fuel sources, it is important therefore to determine if enough land exists around potential ethanol plant locations to meet the potential demands for feedstock. This study determines, through the use of a developed GIS based model, the potential quantities of feedstock that is available in the hinterlands of nine locations in the Republic of Ireland. The results indicate that three locations can meet all its feedstock demands using indigenously grown sugarbeet, while only one location can meet its demands using a combination of indigenous wheat and straw as the two locally sourced feedstocks. (author)

  15. Potential Bioethanol Feedstock Availability Around Nine Locations in the Republic of Ireland

    Directory of Open Access Journals (Sweden)

    Rory Deverell

    2009-03-01

    Full Text Available The Republic of Ireland, like many other countries is trying to diversify energy sources to counteract environmental, political and social concerns. Bioethanol from domestically grown agricultural crops is an indigenously produced alternative fuel that can potentially go towards meeting the goal of diversified energy supply. The Republic of Ireland’s distribution of existing soils and agricultural land-uses limit arable crop land to around 10% of total agricultural area. Demand for land to produce arable crops is expected to decrease, which could open the opportunity for bioethanol production. Bioethanol production plants are required to be of a sufficient scale in order to compete economically with other fuel sources, it is important therefore to determine if enough land exists around potential ethanol plant locations to meet the potential demands for feedstock. This study determines, through the use of a developed GIS based model, the potential quantities of feedstock that is available in the hinterlands of nine locations in the Republic of Ireland. The results indicate that three locations can meet all its feedstock demands using indigenously grown sugarbeet, while only one location can meet its demands using a combination of indigenous wheat and straw as the two locally sourced feedstocks.

  16. CONTEXT MATTERS: THE IMPORTANCE OF MARKET CHARACTERISTICS IN THE VOLATILITY OF FEEDSTOCK COSTS FOR BIOGAS PLANTS.

    Science.gov (United States)

    Mertens, A; Van Meensel, J; Mondelaers, K; Buysse, J

    2015-01-01

    Recently, biogas plant managers in Flanders face increased financial uncertainty. Between 2011 and 2012, 20% of the Flemish biogas plants went bankrupt. Difficulties in obtaining feedstock at stable and affordable prices is one reason why the biogas sector struggles. In literature, contracting is often proposed as a way to decrease the volatility of the feedstock costs. However, these studies generally do not consider the context in which the biogas plant manager needs to buy the feedstock. Yet, this context could be of specific importance when biogas plant managers are in competition with other users of the same biomass type. Silage maize is an example of such a feedstock, as it is both used by dairy farmers and biogas plant managers. Using a combination of qualitative research and agent-based modelling, we investigated the effect of specific characteristics of the silage maize market on the acquisition of local silage maize by biogas plant managers. This paper details the institutional arrangements of the silage maize market in Flanders and the results of a scenario analysis, simulating three different scenarios. As shown by the results, the time of entry into the market, as well as the different institutional arrangements used by the biogas plant managers as opposed to dairy farmers could explain the difficulties in obtaining a stable supply of local silage maize by biogas plants. Our findings can help to develop mitigation strategies addressing these difficulties.

  17. A LabVIEW model incorporating an open-loop arterial impedance and a closed-loop circulatory system.

    Science.gov (United States)

    Cole, R T; Lucas, C L; Cascio, W E; Johnson, T A

    2005-11-01

    While numerous computer models exist for the circulatory system, many are limited in scope, contain unwanted features or incorporate complex components specific to unique experimental situations. Our purpose was to develop a basic, yet multifaceted, computer model of the left heart and systemic circulation in LabVIEW having universal appeal without sacrificing crucial physiologic features. The program we developed employs Windkessel-type impedance models in several open-loop configurations and a closed-loop model coupling a lumped impedance and ventricular pressure source. The open-loop impedance models demonstrate afterload effects on arbitrary aortic pressure/flow inputs. The closed-loop model catalogs the major circulatory waveforms with changes in afterload, preload, and left heart properties. Our model provides an avenue for expanding the use of the ventricular equations through closed-loop coupling that includes a basic coronary circuit. Tested values used for the afterload components and the effects of afterload parameter changes on various waveforms are consistent with published data. We conclude that this model offers the ability to alter several circulatory factors and digitally catalog the most salient features of the pressure/flow waveforms employing a user-friendly platform. These features make the model a useful instructional tool for students as well as a simple experimental tool for cardiovascular research.

  18. Incorporating Protein Biosynthesis into the Saccharomyces cerevisiae Genome-scale Metabolic Model

    DEFF Research Database (Denmark)

    Olivares Hernandez, Roberto

    Based on stoichiometric biochemical equations that occur into the cell, the genome-scale metabolic models can quantify the metabolic fluxes, which are regarded as the final representation of the physiological state of the cell. For Saccharomyces Cerevisiae the genome scale model has been......, translation initiation, translation elongation, translation termination, translation elongation, and mRNA decay. Considering these information from the mechanisms of transcription and translation, we will include this stoichiometric reactions into the genome scale model for S. Cerevisiae to obtain the first...

  19. Incorporating representation of agricultural ecosystems and management within a dynamic biosphere model: Approach, validation, and significance

    Science.gov (United States)

    Kucharik, C.

    2004-12-01

    At the scale of individual fields, crop models have long been used to examine the interactions between soils, vegetation, the atmosphere and human management, using varied levels of numerical sophistication. While previous efforts have contributed significantly towards the advancement of modeling tools, the models themselves are not typically applied across larger continental scales due to a lack of crucial data. Furthermore, many times crop models are used to study a single quantity, process, or cycle in isolation, limiting their value in considering the important tradeoffs between competing ecosystem services such as food production, water quality, and sequestered carbon. In response to the need for a more integrated agricultural modeling approach across the continental scale, an updated agricultural version of a dynamic biosphere model (IBIS) now integrates representations of land-surface physics and soil physics, canopy physiology, terrestrial carbon and nitrogen balance, crop phenology, solute transport, and farm management into a single framework. This version of the IBIS model (Agro-IBIS) uses a short 20 to 60-minute timestep to simulate the rapid exchange of energy, carbon, water, and momentum between soils, vegetative canopies, and the atmosphere. The model can be driven either by site-specific meteorological data or by gridded climate datasets. Mechanistic crop models for corn, soybean, and wheat use physiologically-based representations of leaf photosynthesis, stomatal conductance, and plant respiration. Model validation has been performed using a variety of temporal scale data collected at the following spatial scales: (1) the precision-agriculture scale (5 m), (2) the individual field experiment scale (AmeriFlux), and (3) regional and continental scales using annual USDA county-level yield data and monthly satellite (AVHRR) observations of vegetation characteristics at 0.5 degree resolution. To date, the model has been used with great success to

  20. Alzheimer's disease: analysis of a mathematical model incorporating the role of prions

    OpenAIRE

    Helal, Mohamed; Hingant, Erwan; Pujo-Menjouet, Laurent; Webb, Glenn F.

    2013-01-01

    We introduce a mathematical model of the in vivo progression of Alzheimer's disease with focus on the role of prions in memory impairment. Our model consists of differential equations that describe the dynamic formation of {\\beta}-amyloid plaques based on the concentrations of A{\\beta} oligomers, PrPC proteins, and the A{\\beta}-x-PrPC complex, which are hypothesized to be responsible for synaptic toxicity. We prove the well-posedness of the model and provided stability results for its unique ...

  1. Incorporating Floating Surface Objects into a Fully Dispersive Surface Wave Model

    Science.gov (United States)

    2016-04-19

    Decimation and Interpolation (PDI) Method was dded to NHWAVE by Shi et al. (2015) , who confirmed that the dy- amic pressure can be modeled accurately... cluster Farber located at he University of Delaware. Using 48 cores, it took about 8 h for a imulation of 10 0 0 s. The 10 m water depth was selected to re... decimation and interpolation (PDI) method for a baroclinic non-hydrostatic model. Ocean Mod. 96, 265–279 . 26 M.D. Orzech et al. / Ocean Modelling 102 (2016

  2. Impact of Technology and Feedstock Choice on the Environmental Footprint of Biofuels

    Science.gov (United States)

    Schultz, P. B.; Dodder, R. S.

    2012-12-01

    The implementation of the U.S. Renewable Fuel Standard program (RFS2) has led to a dramatic shift in the use of biofuel in the U.S. transportation system over the last decade. To satisfy this demand, the production of U.S. corn-based ethanol has grown rapidly, with an average increase of over 25% annually from 2002 to 2010. RFS2 requires a similarly steep increase in the production of advanced biofuels, such as cellulosic ethanol. Unlike corn-based ethanol, which is derived from the biochemical fermentation of sugars in wet and dry mills, it is likely that a more diverse suite of technologies will need to be developed to be able to meet the advanced biofuel RFS2 targets, including biochemical as well as thermochemical (e.g., gasification and pyrolysis) approaches. Rather than relying on energy crops, a potential advantage of thermochemical approaches is the ability to use a wider variety of feedstocks, including municipal solid waste and wood waste. In this work, we conduct a system-level analysis to understand how technology and feedstock choice can impact the environmental footprint of biofuels in the U.S. We use a least-cost optimization model of the U.S. energy system to account for interactions between various components of the energy system: industrial, transportation, electric, and residential/commercial sectors. The model was used to understand the scale of feedstock demand required from dedicated energy crops, as well as other biomass feedstocks, in order to meet the RFS2 mandate. On a regional basis, we compare the overall water-consumption and land requirements for biofuels production given a suite of liquid-fuel production technologies. By considering a range of scenarios, we examine how the use of various feedstocks (e.g., agricultural residues, wood wastes, mill residues and municipal wastes) can be used to off-set environmental impacts as compared to relying solely on energy crops.

  3. On Optimizing H. 264/AVC Rate Control by Improving R-D Model and Incorporating HVS Characteristics

    Directory of Open Access Journals (Sweden)

    Jiang Gangyi

    2010-01-01

    Full Text Available The state-of-the-art JVT-G012 rate control algorithm of H.264 is improved from two aspects. First, the quadratic rate-distortion (R-D model is modified based on both empirical observations and theoretical analysis. Second, based on the existing physiological and psychological research findings of human vision, the rate control algorithm is optimized by incorporating the main characteristics of the human visual system (HVS such as contrast sensitivity, multichannel theory, and masking effect. Experiments are conducted, and experimental results show that the improved algorithm can simultaneously enhance the overall subjective visual quality and improve the rate control precision effectively.

  4. Improving the phenotype predictions of a yeast genome-scale metabolic model by incorporating enzymatic constraints

    DEFF Research Database (Denmark)

    Sanchez, Benjamin J.; Zhang, Xi-Cheng; Nilsson, Avlant

    2017-01-01

    , which act as limitations on metabolic fluxes, are not taken into account. Here, we present GECKO, a method that enhances a GEM to account for enzymes as part of reactions, thereby ensuring that each metabolic flux does not exceed its maximum capacity, equal to the product of the enzyme's abundance...... and turnover number. We applied GECKO to a Saccharomyces cerevisiae GEM and demonstrated that the new model could correctly describe phenotypes that the previous model could not, particularly under high enzymatic pressure conditions, such as yeast growing on different carbon sources in excess, coping...... with stress, or overexpressing a specific pathway. GECKO also allows to directly integrate quantitative proteomics data; by doing so, we significantly reduced flux variability of the model, in over 60% of metabolic reactions. Additionally, the model gives insight into the distribution of enzyme usage between...

  5. Characterization of Steels Using a Revised Kinematic Hardening Model Incorporating Bauschinger Effect

    National Research Council Canada - National Science Library

    Parker, Anthony

    2002-01-01

    A new variant of the nonlinear kinematic hardening model is proposed that accommodates both nonlinear and linear strain hardening during initial tensile loading and reduced elastic modulus during initial load reversal...

  6. Forecasting energy consumption using a grey model improved by incorporating genetic programming

    International Nuclear Information System (INIS)

    Lee, Yi-Shian; Tong, Lee-Ing

    2011-01-01

    Energy consumption is an important economic index, which reflects the industrial development of a city or a country. Forecasting energy consumption by conventional statistical methods usually requires the making of assumptions such as the normal distribution of energy consumption data or on a large sample size. However, the data collected on energy consumption are often very few or non-normal. Since a grey forecasting model, based on grey theory, can be constructed for at least four data points or ambiguity data, it can be adopted to forecast energy consumption. In some cases, however, a grey forecasting model may yield large forecasting errors. To minimize such errors, this study develops an improved grey forecasting model, which combines residual modification with genetic programming sign estimation. Finally, a real case of Chinese energy consumption is considered to demonstrate the effectiveness of the proposed forecasting model.

  7. Simulation of a severe convective storm using a numerical model with explicitly incorporated aerosols

    Science.gov (United States)

    Lompar, Miloš; Ćurić, Mladjen; Romanic, Djordje

    2017-09-01

    Despite an important role the aerosols play in all stages of cloud lifecycle, their representation in numerical weather prediction models is often rather crude. This paper investigates the effects the explicit versus implicit inclusion of aerosols in a microphysics parameterization scheme in Weather Research and Forecasting (WRF) - Advanced Research WRF (WRF-ARW) model has on cloud dynamics and microphysics. The testbed selected for this study is a severe mesoscale convective system with supercells that struck west and central parts of Serbia in the afternoon of July 21, 2014. Numerical products of two model runs, i.e. one with aerosols explicitly (WRF-AE) included and another with aerosols implicitly (WRF-AI) assumed, are compared against precipitation measurements from surface network of rain gauges, as well as against radar and satellite observations. The WRF-AE model accurately captured the transportation of dust from the north Africa over the Mediterranean and to the Balkan region. On smaller scales, both models displaced the locations of clouds situated above west and central Serbia towards southeast and under-predicted the maximum values of composite radar reflectivity. Similar to satellite images, WRF-AE shows the mesoscale convective system as a merged cluster of cumulonimbus clouds. Both models over-predicted the precipitation amounts; WRF-AE over-predictions are particularly pronounced in the zones of light rain, while WRF-AI gave larger outliers. Unlike WRF-AI, the WRF-AE approach enables the modelling of time evolution and influx of aerosols into the cloud which could be of practical importance in weather forecasting and weather modification. Several likely causes for discrepancies between models and observations are discussed and prospects for further research in this field are outlined.

  8. Debris flow analysis with a one dimensional dynamic run-out model that incorporates entrained material

    Science.gov (United States)

    Luna, Byron Quan; Remaître, Alexandre; van Asch, Theo; Malet, Jean-Philippe; van Westen, Cees

    2010-05-01

    Estimating the magnitude and the intensity of rapid landslides like debris flows is fundamental to evaluate quantitatively the hazard in a specific location. Intensity varies through the travelled course of the flow and can be described by physical features such as deposited volume, velocities, height of the flow, impact forces and pressures. Dynamic run-out models are able to characterize the distribution of the material, its intensity and define the zone where the elements will experience an impact. These models can provide valuable inputs for vulnerability and risk calculations. However, most dynamic run-out models assume a constant volume during the motion of the flow, ignoring the important role of material entrained along its path. Consequently, they neglect that the increase of volume enhances the mobility of the flow and can significantly influence the size of the potential impact area. An appropriate erosion mechanism needs to be established in the analyses of debris flows that will improve the results of dynamic modeling and consequently the quantitative evaluation of risk. The objective is to present and test a simple 1D debris flow model with a material entrainment concept based on limit equilibrium considerations and the generation of excess pore water pressure through undrained loading of the in situ bed material. The debris flow propagation model is based on a one dimensional finite difference solution of a depth-averaged form of the Navier-Stokes equations of fluid motions. The flow is treated as a laminar one phase material, which behavior is controlled by a visco-plastic Coulomb-Bingham rheology. The model parameters are evaluated and the model performance is tested on a debris flow event that occurred in 2003 in the Faucon torrent (Southern French Alps).

  9. Statistical inference and modelling for nosocomial infections and the incorporation of whole genome sequence data

    OpenAIRE

    Worby, Colin J.

    2013-01-01

    Healthcare-associated infections (HCAIs) remain a problem worldwide, and can cause severe illness and death. The increasing level of antibiotic resistance among bacteria that cause HCAIs limits infection treatment options, and is a major concern. Statistical modelling is a vital tool in developing an understanding of HCAI transmission dynamics. In this thesis, stochastic epidemic models are developed and used with the aim of investigating methicillin-resistant Staphylococcus aureus (MRSA) tra...

  10. Creating a process for incorporating epidemiological modelling into outbreak management decisions.

    Science.gov (United States)

    Akselrod, Hana; Mercon, Monica; Kirkeby Risoe, Petter; Schlegelmilch, Jeffrey; McGovern, Joanne; Bogucki, Sandy

    2012-01-01

    Modern computational models of infectious diseases greatly enhance our ability to understand new infectious threats and assess the effects of different interventions. The recently-released CDC Framework for Preventing Infectious Diseases calls for increased use of predictive modelling of epidemic emergence for public health preparedness. Currently, the utility of these technologies in preparedness and response to outbreaks is limited by gaps between modelling output and information requirements for incident management. The authors propose an operational structure that will facilitate integration of modelling capabilities into action planning for outbreak management, using the Incident Command System (ICS) and Synchronization Matrix framework. It is designed to be adaptable and scalable for use by state and local planners under the National Response Framework (NRF) and Emergency Support Function #8 (ESF-8). Specific epidemiological modelling requirements are described, and integrated with the core processes for public health emergency decision support. These methods can be used in checklist format to align prospective or real-time modelling output with anticipated decision points, and guide strategic situational assessments at the community level. It is anticipated that formalising these processes will facilitate translation of the CDC's policy guidance from theory to practice during public health emergencies involving infectious outbreaks.

  11. Enhanced stability of car-following model upon incorporation of short-term driving memory

    Science.gov (United States)

    Liu, Da-Wei; Shi, Zhong-Ke; Ai, Wen-Huan

    2017-06-01

    Based on the full velocity difference model, a new car-following model is developed to investigate the effect of short-term driving memory on traffic flow in this paper. Short-term driving memory is introduced as the influence factor of driver's anticipation behavior. The stability condition of the newly developed model is derived and the modified Korteweg-de Vries (mKdV) equation is constructed to describe the traffic behavior near the critical point. Via numerical method, evolution of a small perturbation is investigated firstly. The results show that the improvement of this new car-following model over the previous ones lies in the fact that the new model can improve the traffic stability. Starting and breaking processes of vehicles in the signalized intersection are also investigated. The numerical simulations illustrate that the new model can successfully describe the driver's anticipation behavior, and that the efficiency and safety of the vehicles passing through the signalized intersection are improved by considering short-term driving memory.

  12. A new mathematical model of gastrointestinal transit incorporating age- and gender-dependent physiological parameters

    International Nuclear Information System (INIS)

    Stubbs, J.B.

    1992-01-01

    As part of the revision by the International Commission on Radiological Protection (ICRP) of its report on Reference Man, an extensive review of the literature regarding anatomy and morphology of the gastrointestinal (GI) tract has been completed. Data on age- and gender-dependent GI physiology and motility may be included in the proposed ICRP report. A new mathematical model describing the transit of substances through the GI tract as well as the absorption and secretion of material in the GI tract has been developed. This mathematical description of GI tract kinetics utilizes more physiologically accurate transit processes than the mathematically simple, but nonphysiological, GI tract model that was used in ICRP Report 30. The proposed model uses a combination of zero- and first-order kinetics to describe motility. Some of the physiological parameters that the new model accounts for include sex, age, pathophysiological condition and meal phase (solid versus liquid). A computer algorithm, written in BASIC, based on this new model has been derived and results are compared to those of the ICRP-30 model

  13. Incorporating rainfall uncertainty in a SWAT model: the river Zenne basin (Belgium) case study

    Science.gov (United States)

    Tolessa Leta, Olkeba; Nossent, Jiri; van Griensven, Ann; Bauwens, Willy

    2013-04-01

    The European Union Water Framework Directive (EU-WFD) called its member countries to achieve a good ecological status for all inland and coastal water bodies by 2015. According to recent studies, the river Zenne (Belgium) is far from this objective. Therefore, an interuniversity and multidisciplinary project "Towards a Good Ecological Status in the river Zenne (GESZ)" was launched to evaluate the effects of wastewater management plans on the river. In this project, different models have been developed and integrated using the Open Modelling Interface (OpenMI). The hydrologic, semi-distributed Soil and Water Assessment Tool (SWAT) is hereby used as one of the model components in the integrated modelling chain in order to model the upland catchment processes. The assessment of the uncertainty of SWAT is an essential aspect of the decision making process, in order to design robust management strategies that take the predicted uncertainties into account. Model uncertainty stems from the uncertainties on the model parameters, the input data (e.g, rainfall), the calibration data (e.g., stream flows) and on the model structure itself. The objective of this paper is to assess the first three sources of uncertainty in a SWAT model of the river Zenne basin. For the assessment of rainfall measurement uncertainty, first, we identified independent rainfall periods, based on the daily precipitation and stream flow observations and using the Water Engineering Time Series PROcessing tool (WETSPRO). Secondly, we assigned a rainfall multiplier parameter for each of the independent rainfall periods, which serves as a multiplicative input error corruption. Finally, we treated these multipliers as latent parameters in the model optimization and uncertainty analysis (UA). For parameter uncertainty assessment, due to the high number of parameters of the SWAT model, first, we screened out its most sensitive parameters using the Latin Hypercube One-factor-At-a-Time (LH-OAT) technique

  14. Incorporation of the time aspect into the liability-threshold model for case-control-family data

    DEFF Research Database (Denmark)

    Cederkvist, Luise; Holst, Klaus K.; Andersen, Klaus K.

    2017-01-01

    Familial aggregation and the role of genetic and environmental factors can be investigated through family studies analysed using the liability-threshold model. The liability-threshold model ignores the timing of events including the age of disease onset and right censoring, which can lead...... to estimates that are difficult to interpret and are potentially biased. We incorporate the time aspect into the liability-threshold model for case-control-family data following the same approach that has been applied in the twin setting. Thus, the data are considered as arising from a competing risks setting...... and inverse probability of censoring weights are used to adjust for right censoring. In the case-control-family setting, recognising the existence of competing events is highly relevant to the sampling of control probands. Because of the presence of multiple family members who may be censored at different...

  15. A model for determination of human foetus irradiation during intrauterine development when the mother incorporates iodine 131

    International Nuclear Information System (INIS)

    Vasilev, V.; Doncheva, B.

    1989-01-01

    A model is presented for irradiation calculation of human foetus during weeks 8-15 of the intrauterine development, when the mother chronically incorporates iodine 131. This period is critical for the nervous system of the foetus. Compared to some other author's models, the method proposed eliminates some uncertainties and takes into account the changes in the activity of mother's thyroid in time. The model is built on the base of data from 131 I-kinetics of pregnant women and experimental mice. A formula is proposed for total foetus irradiation calculation including: the internal γ and β irradiation; the external γ and β irradiation from the mother as a whole; and the external γ irradiation from the mother's thyroid

  16. The Isinglass Auroral Sounding Rocket Campaign: data synthesis incorporating remote sensing, in situ observations, and modelling

    Science.gov (United States)

    Lynch, K. A.; Clayton, R.; Roberts, T. M.; Hampton, D. L.; Conde, M.; Zettergren, M. D.; Burleigh, M.; Samara, M.; Michell, R.; Grubbs, G. A., II; Lessard, M.; Hysell, D. L.; Varney, R. H.; Reimer, A.

    2017-12-01

    The NASA auroral sounding rocket mission Isinglass was launched from Poker Flat Alaska in winter 2017. This mission consists of two separate multi-payload sounding rockets, over an array of groundbased observations, including radars and filtered cameras. The science goal is to collect two case studies, in two different auroral events, of the gradient scale sizes of auroral disturbances in the ionosphere. Data from the in situ payloads and the groundbased observations will be synthesized and fed into an ionospheric model, and the results will be studied to learn about which scale sizes of ionospheric structuring have significance for magnetosphere-ionosphere auroral coupling. The in situ instrumentation includes thermal ion sensors (at 5 points on the second flight), thermal electron sensors (at 2 points), DC magnetic fields (2 point), DC electric fields (one point, plus the 4 low-resource thermal ion RPA observations of drift on the second flight), and an auroral precipitation sensor (one point). The groundbased array includes filtered auroral imagers, the PFISR and SuperDarn radars, a coherent scatter radar, and a Fabry-Perot interferometer array. The ionospheric model to be used is a 3d electrostatic model including the effects of ionospheric chemistry. One observational and modelling goal for the mission is to move both observations and models of auroral arc systems into the third (along-arc) dimension. Modern assimilative tools combined with multipoint but low-resource observations allow a new view of the auroral ionosphere, that should allow us to learn more about the auroral zone as a coupled system. Conjugate case studies such as the Isinglass rocket flights allow for a test of the models' intepretation by comparing to in situ data. We aim to develop and improve ionospheric models to the point where they can be used to interpret remote sensing data with confidence without the checkpoint of in situ comparison.

  17. A kinematic wave model in Lagrangian coordinates incorporating capacity drop: Application to homogeneous road stretches and discontinuities

    Science.gov (United States)

    Yuan, Kai; Knoop, Victor L.; Hoogendoorn, Serge P.

    2017-01-01

    On freeways, congestion always leads to capacity drop. This means the queue discharge rate is lower than the pre-queue capacity. Our recent research findings indicate that the queue discharge rate increases with the speed in congestion, that is the capacity drop is strongly correlated with the congestion state. Incorporating this varying capacity drop into a kinematic wave model is essential for assessing consequences of control strategies. However, to the best of authors' knowledge, no such a model exists. This paper fills the research gap by presenting a Lagrangian kinematic wave model. "Lagrangian" denotes that the new model is solved in Lagrangian coordinates. The new model can give capacity drops accompanying both of stop-and-go waves (on homogeneous freeway section) and standing queues (at nodes) in a network. The new model can be applied in a network operation. In this Lagrangian kinematic wave model, the queue discharge rate (or the capacity drop) is a function of vehicular speed in traffic jams. Four case studies on links as well as at lane-drop and on-ramp nodes show that the Lagrangian kinematic wave model can give capacity drops well, consistent with empirical observations.

  18. Modeling Mode Choice Behavior Incorporating Household and Individual Sociodemographics and Travel Attributes Based on Rough Sets Theory

    Directory of Open Access Journals (Sweden)

    Long Cheng

    2014-01-01

    Full Text Available Most traditional mode choice models are based on the principle of random utility maximization derived from econometric theory. Alternatively, mode choice modeling can be regarded as a pattern recognition problem reflected from the explanatory variables of determining the choices between alternatives. The paper applies the knowledge discovery technique of rough sets theory to model travel mode choices incorporating household and individual sociodemographics and travel information, and to identify the significance of each attribute. The study uses the detailed travel diary survey data of Changxing county which contains information on both household and individual travel behaviors for model estimation and evaluation. The knowledge is presented in the form of easily understood IF-THEN statements or rules which reveal how each attribute influences mode choice behavior. These rules are then used to predict travel mode choices from information held about previously unseen individuals and the classification performance is assessed. The rough sets model shows high robustness and good predictive ability. The most significant condition attributes identified to determine travel mode choices are gender, distance, household annual income, and occupation. Comparative evaluation with the MNL model also proves that the rough sets model gives superior prediction accuracy and coverage on travel mode choice modeling.

  19. Incorporation of lysosomal sequestration in the mechanistic model for prediction of tissue distribution of basic drugs.

    Science.gov (United States)

    Assmus, Frauke; Houston, J Brian; Galetin, Aleksandra

    2017-11-15

    The prediction of tissue-to-plasma water partition coefficients (Kpu) from in vitro and in silico data using the tissue-composition based model (Rodgers & Rowland, J Pharm Sci. 2005, 94(6):1237-48.) is well established. However, distribution of basic drugs, in particular into lysosome-rich lung tissue, tends to be under-predicted by this approach. The aim of this study was to develop an extended mechanistic model for the prediction of Kpu which accounts for lysosomal sequestration and the contribution of different cell types in the tissue of interest. The extended model is based on compound-specific physicochemical properties and tissue composition data to describe drug ionization, distribution into tissue water and drug binding to neutral lipids, neutral phospholipids and acidic phospholipids in tissues, including lysosomes. Physiological data on the types of cells contributing to lung, kidney and liver, their lysosomal content and lysosomal pH were collated from the literature. The predictive power of the extended mechanistic model was evaluated using a dataset of 28 basic drugs (pK a ≥7.8, 17 β-blockers, 11 structurally diverse drugs) for which experimentally determined Kpu data in rat tissue have been reported. Accounting for the lysosomal sequestration in the extended mechanistic model improved the accuracy of Kpu predictions in lung compared to the original Rodgers model (56% drugs within 2-fold or 88% within 3-fold of observed values). Reduction in the extent of Kpu under-prediction was also evident in liver and kidney. However, consideration of lysosomal sequestration increased the occurrence of over-predictions, yielding overall comparable model performances for kidney and liver, with 68% and 54% of Kpu values within 2-fold error, respectively. High lysosomal concentration ratios relative to cytosol (>1000-fold) were predicted for the drugs investigated; the extent differed depending on the lysosomal pH and concentration of acidic phospholipids among

  20. Incorporating microbial dormancy dynamics into soil decomposition models to improve quantification of soil carbon dynamics of northern temperate forests

    Energy Technology Data Exchange (ETDEWEB)

    He, Yujie [Purdue Univ., West Lafayette, IN (United States). Dept. of Earth, Atmospheric, and Planetary Sciences; Yang, Jinyan [Univ. of Georgia, Athens, GA (United States). Warnell School of Forestry and Natural Resources; Northeast Forestry Univ., Harbin (China). Center for Ecological Research; Zhuang, Qianlai [Purdue Univ., West Lafayette, IN (United States). Dept. of Earth, Atmospheric, and Planetary Sciences; Purdue Univ., West Lafayette, IN (United States). Dept. of Agronomy; Harden, Jennifer W. [U.S. Geological Survey, Menlo Park, CA (United States); McGuire, Anthony D. [Alaska Cooperative Fish and Wildlife Research Unit, U.S. Geological Survey, Univ. of Alaska, Fairbanks, AK (United States). U.S. Geological Survey, Alaska Cooperative Fish and Wildlife Research Unit; Liu, Yaling [Purdue Univ., West Lafayette, IN (United States). Dept. of Earth, Atmospheric, and Planetary Sciences; Wang, Gangsheng [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States). Climate Change Science Inst. and Environmental Sciences Division; Gu, Lianhong [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States). Environmental Sciences Division

    2015-11-20

    Soil carbon dynamics of terrestrial ecosystems play a significant role in the global carbon cycle. Microbial-based decomposition models have seen much growth recently for quantifying this role, yet dormancy as a common strategy used by microorganisms has not usually been represented and tested in these models against field observations. Here in this study we developed an explicit microbial-enzyme decomposition model and examined model performance with and without representation of microbial dormancy at six temperate forest sites of different forest types. We then extrapolated the model to global temperate forest ecosystems to investigate biogeochemical controls on soil heterotrophic respiration and microbial dormancy dynamics at different temporal-spatial scales. The dormancy model consistently produced better match with field-observed heterotrophic soil CO2 efflux (RH) than the no dormancy model. Our regional modeling results further indicated that models with dormancy were able to produce more realistic magnitude of microbial biomass (<2% of soil organic carbon) and soil RH (7.5 ± 2.4 PgCyr-1). Spatial correlation analysis showed that soil organic carbon content was the dominating factor (correlation coefficient = 0.4-0.6) in the simulated spatial pattern of soil RH with both models. In contrast to strong temporal and local controls of soil temperature and moisture on microbial dormancy, our modeling results showed that soil carbon-to-nitrogen ratio (C:N) was a major regulating factor at regional scales (correlation coefficient = -0.43 to -0.58), indicating scale-dependent biogeochemical controls on microbial dynamics. Our findings suggest that incorporating microbial dormancy could improve the realism of microbial-based decomposition models and enhance the integration of soil experiments and mechanistically based modeling.

  1. Dominant Height Model for Site Classification of Eucalyptus grandis Incorporating Climatic Variables

    Directory of Open Access Journals (Sweden)

    José Roberto Soares Scolforo

    2013-01-01

    Full Text Available This study tested the effects of inserting climatic variables in Eucalyptus grandis as covariables of a dominant height model, which for site index classification is usually related to age alone. Dominant height values ranging from 1 to 12 years of age located in the Southeast region of Brazil were used, as well as data from 19 automatic meteorological stations from the area. The Chapman-Richards model was chosen to represent dominant height as a function of age. To include the environmental variables a modifier was included in the asymptote of the model. The asymptote was chosen since this parameter is responsible for the maximum value which the dominant height can reach. Of the four environmental variables most responsible for database variation, the two with the highest correlation to the mean annual increment in dominant height (mean monthly precipitation and temperature were selected to compose the asymptote modifier. Model validation showed a gain in precision of 33% (reduction of the standard error of estimate when climatic variables were inserted in the model. Possible applications of the method include the estimation of site capacity in regions lacking any planting history, as well as updating forest inventory data based on past climate regimes.

  2. Ultrasonically assisted drilling: A finite-element model incorporating acoustic softening effects

    Science.gov (United States)

    Phadnis, V. A.; Roy, A.; Silberschmidt, V. V.

    2013-07-01

    Ultrasonically assisted drilling (UAD) is a novel machining technique suitable for drilling in hard-to-machine quasi-brittle materials such as carbon fibre reinforced polymer composites (CFRP). UAD has been shown to possess several advantages compared to conventional drilling (CD), including reduced thrust forces, diminished burr formation at drill exit and an overall improvement in roundness and surface finish of the drilled hole. Recently, our in-house experiments of UAD in CFRP composites demonstrated remarkable reductions in thrust-force and torque measurements (average force reductions in excess of 80%) when compared to CD with the same machining parameters. In this study, a 3D finite-element model of drilling in CFRP is developed. In order to model acoustic (ultrasonic) softening effects, a phenomenological model, which accounts for ultrasonically induced plastic strain, was implemented in ABAQUS/Explicit. The model also accounts for dynamic frictional effects, which also contribute to the overall improved machining characteristics in UAD. The model is validated with experimental findings, where an excellent correlation between the reduced thrust force and torque magnitude was achieved.

  3. Development of a prototype mesoscale computer model incorporating treatment of topography

    International Nuclear Information System (INIS)

    Apsimon, H.; Kitson, K.; Fawcett, M.; Goddard, A.J.H.

    1984-01-01

    Models are available for simulating dispersal of accidental releases, using mass-consistent wind-fields and accounting for site-specific topography. These techniques were examined critically to see if they might be improved, and to assess their limitations. An improved model, windfield adjusted for topography (WAFT), was developed (with advantages over MATHEW used in the Atmospheric Release Advisory Capability - ARAC system). To simulate dispersion in the windfields produced by WAFT and calculate time integrated air concentrations and dry and wet deposition the TOMCATS model was developed. It treats the release as an assembly of pseudo-particles using Monte Carlo techniques to simulate turbulent displacements. It allows for larger eddy effects in the horizontal turbulence spectrum. Wet deposition is calculated using inhomogeneous rainfields evolving in time and space. The models were assessed, applying them to hypothetical releases in complex terrain, using typical data applicable in accident conditions, and undertaking sensitivity studies. One finds considerable uncertainty in results produced by these models. Although useful for post-facto analysis, such limitations cast doubt on their advantages, relative to simpler techniques, during an actual emergency

  4. Modeling & Informatics at Vertex Pharmaceuticals Incorporated: our philosophy for sustained impact.

    Science.gov (United States)

    McGaughey, Georgia; Patrick Walters, W

    2017-03-01

    Molecular modelers and informaticians have the unique opportunity to integrate cross-functional data using a myriad of tools, methods and visuals to generate information. Using their drug discovery expertise, information is transformed to knowledge that impacts drug discovery. These insights are often times formulated locally and then applied more broadly, which influence the discovery of new medicines. This is particularly true in an organization where the members are exposed to projects throughout an organization, such as in the case of the global Modeling & Informatics group at Vertex Pharmaceuticals. From its inception, Vertex has been a leader in the development and use of computational methods for drug discovery. In this paper, we describe the Modeling & Informatics group at Vertex and the underlying philosophy, which has driven this team to sustain impact on the discovery of first-in-class transformative medicines.

  5. Incorporation of leaf nitrogen observations for biochemical and environmental modeling of photosynthesis and evapotranspiration

    DEFF Research Database (Denmark)

    Boegh, E; Gjetterman, B; Abrahamsen, P

    2007-01-01

    impact on CO2 sequestration processes complicates the modeling of carbon cycle feedbacks to climate change. The use of remote sensing constitutes a valuable data source to quantify and investigate impacts of bulk leaf N contents, however information on the vertical leaf N distribution and its...... relation to photosynthetic (Rubisco) capacity should also be known to quantify leaf N impacts on canopy photosynthesis. In this study, impacts of the amount and vertical distribution of leaf N contents on canopy photosynthesis were investigated by combining field measurements and photosynthesis modelling....... While most canopy photosynthesis models assume an exponential vertical profile of leaf N contents in the canopy, the field measurements showed that well-fertilized fields may have a uniform or exponential profile, and senescent canopies have reduced levels of N contents in upper leaves. The sensitivity...

  6. Incorporation of leaf nitrogen observations for biochemical and environmental modeling of photosynthesis and evapotranspiration

    DEFF Research Database (Denmark)

    Bøgh, E.; Gjettermann, Birgitte; Abrahamsen, Per

    2007-01-01

    relation to photosynthetic (Rubisco) capacity should also be known to quantify leaf N impacts on canopy photosynthesis. In this study, impacts of the amount and vertical distribution of leaf N contents on canopy photosynthesis were investigated by combining field measurements and photosynthesis modelling....... While most canopy photosynthesis models assume an exponential vertical profile of leaf N contents in the canopy, the field measurements showed that well-fertilized fields may have a uniform or exponential profile, and senescent canopies have reduced levels of N contents in upper leaves. The sensitivity...... of simulated canopy photosynthesis to the different (observed) N profiles was examined using a multi-layer sun/shade biochemically based photosynthesis model and found to be important; ie. for a well-fertilized barley field, the use of exponential instead of uniform vertical N profiles increased the annual...

  7. Modified Johnson-Cook model incorporated with electroplasticity for uniaxial tension under a pulsed electric current

    Science.gov (United States)

    Kim, Moon-Jo; Jeong, Hye-Jin; Park, Ju-Won; Hong, Sung-Tae; Han, Heung Nam

    2018-01-01

    An empirical expression describing the electroplastic deformation behavior is suggested based on the Johnson-Cook (JC) model by adding several functions to consider both thermal and athermal electric current effects. Tensile deformation behaviors are carried out for an AZ31 magnesium alloy and an Al-Mg-Si alloy under pulsed electric current at various current densities with a fixed duration of electric current. To describe the flow curves under electric current, a modified JC model is proposed to take the electric current effect into account. Phenomenological descriptions of the adopted parameters in the equation are made. The modified JC model suggested in the present study is capable of describing the tensile deformation behaviors under pulsed electric current reasonably well.

  8. A Transient 3D-CFD Model Incorporating Biological Processes for Use in Tissue Engineering

    DEFF Research Database (Denmark)

    Krühne, Ulrich; Wendt, D.; Martin, I.

    2010-01-01

    are considered in the model. In a variation of the model the growth of the biomass is influenced by the fluid dynamic induced shear stress level, which the cells are exposed to. In parallel an experimental growth of stem cells has been performed in a 3D perfusion reactor system and the culturing has been stopped...... after 2, 8 and 13 days. The development of the cells is compared to the simulated growth of cells and it is attempted to draw a conclusion about the impact of the shear stress on the cell growth. Keyword: Computational fluid dynamics (CFD),Micro pores,Scaffold,Bioreactor,Fluid structure interaction...

  9. Effect of Blended Feedstock on Pyrolysis Oil Composition

    Energy Technology Data Exchange (ETDEWEB)

    Smith, Kristin M [National Renewable Energy Laboratory (NREL), Golden, CO (United States); Gaston, Katherine R [National Renewable Energy Laboratory (NREL), Golden, CO (United States)

    2017-09-28

    Current techno-economic analysis results indicate biomass feedstock cost represents 27% of the overall minimum fuel selling price for biofuels produced from fast pyrolysis followed by hydrotreating (hydro-deoxygenation, HDO). As a result, blended feedstocks have been proposed as a way to both reduce cost as well as tailor key chemistry for improved fuel quality. For this study, two feedstocks were provided by Idaho National Laboratory (INL). Both were pyrolyzed and collected under the same conditions in the National Renewable Energy Laboratory's (NREL) Thermochemical Process Development Unit (TCPDU). The resulting oil properties were then analyzed and characterized for statistical differences.

  10. Method for determining processability of a hydrocarbon containing feedstock

    Energy Technology Data Exchange (ETDEWEB)

    Schabron, John F.; Rovani, Jr., Joseph F.

    2013-09-10

    Disclosed herein is a method involving the steps of (a) precipitating an amount of asphaltenes from a liquid sample of a first hydrocarbon-containing feedstock having solvated asphaltenes therein with one or more first solvents in a column; (b) determining one or more solubility characteristics of the precipitated asphaltenes; (c) analyzing the one or more solubility characteristics of the precipitated asphaltenes; and (d) correlating a measurement of feedstock reactivity for the first hydrocarbon-containing feedstock sample with a mathematical parameter derived from the results of analyzing the one or more solubility characteristics of the precipitated asphaltenes.

  11. Mechanistic description of population dynamics using dynamic energy budget theory incorporated into integral projection models

    NARCIS (Netherlands)

    Smallegange, I.M.; Caswell, H.; Toorians, M.E.M.; de Roos, A.M.

    1. Integral projection models (IPMs) provide a powerful approach to investigate ecological and rapid evolutionary change in quantitative life-history characteristics and population dynamics. IPMs are constructed from functions that describe the demographic rates – survival, growth and reproduction –

  12. Process model for ammonia volatilization from anaerobic swine lagoons incorporating varying wind speeds and biogas bubbling

    Science.gov (United States)

    Ammonia volatilization from treatment lagoons varies widely with the total ammonia concentration, pH, temperature, suspended solids, atmospheric ammonia concentration above the water surface, and wind speed. Ammonia emissions were estimated with a process-based mechanistic model integrating ammonia ...

  13. Numerical Computation of a Continuous-thrust State Transition Matrix Incorporating Accurate Hardware and Ephemeris Models

    Science.gov (United States)

    Ellison, Donald; Conway, Bruce; Englander, Jacob

    2015-01-01

    A significant body of work exists showing that providing a nonlinear programming (NLP) solver with expressions for the problem constraint gradient substantially increases the speed of program execution and can also improve the robustness of convergence, especially for local optimizers. Calculation of these derivatives is often accomplished through the computation of spacecraft's state transition matrix (STM). If the two-body gravitational model is employed as is often done in the context of preliminary design, closed form expressions for these derivatives may be provided. If a high fidelity dynamics model, that might include perturbing forces such as the gravitational effect from multiple third bodies and solar radiation pressure is used then these STM's must be computed numerically. We present a method for the power hardward model and a full ephemeris model. An adaptive-step embedded eight order Dormand-Prince numerical integrator is discussed and a method for the computation of the time of flight derivatives in this framework is presented. The use of these numerically calculated derivatieves offer a substantial improvement over finite differencing in the context of a global optimizer. Specifically the inclusion of these STM's into the low thrust missiondesign tool chain in use at NASA Goddard Spaceflight Center allows for an increased preliminary mission design cadence.

  14. Incorporating unreliability of transit in transport demand models: theoretical and practical approach

    NARCIS (Netherlands)

    van Oort, N.; Brands, Ties; de Romph, E.; Aceves Flores, J.

    2014-01-01

    Nowadays, transport demand models do not explicitly evaluate the impacts of service reliability of transit. Service reliability of transit systems is adversely experienced by users, as it causes additional travel time and unsecure arrival times. Because of this, travelers are likely to perceive a

  15. A model of driver steering control incorporating the driver's sensing of steering torque

    Science.gov (United States)

    Kim, Namho; Cole, David J.

    2011-10-01

    Steering feel, or steering torque feedback, is widely regarded as an important aspect of the handling quality of a vehicle. Despite this, there is little theoretical understanding of its role. This paper describes an initial attempt to model the role of steering torque feedback arising from lateral tyre forces. The path-following control of a nonlinear vehicle model is implemented using a time-varying model predictive controller. A series of Kalman filters are used to represent the driver's ability to generate estimates of the system states from noisy sensory measurements, including the steering torque. It is found that under constant road friction conditions, the steering torque feedback reduces path-following errors provided the friction is sufficiently high to prevent frequent saturation of the tyres. When the driver model is extended to allow identification of, and adaptation to, a varying friction condition, it is found that the steering torque assists in the accurate identification of the friction condition. The simulation results give insight into the role of steering torque feedback arising from lateral tyre forces. The paper concludes with recommendations for further work.

  16. A microstructurally based continuum model of cartilage viscoelasticity and permeability incorporating measured statistical fiber orientations.

    Science.gov (United States)

    Pierce, David M; Unterberger, Michael J; Trobin, Werner; Ricken, Tim; Holzapfel, Gerhard A

    2016-02-01

    The remarkable mechanical properties of cartilage derive from an interplay of isotropically distributed, densely packed and negatively charged proteoglycans; a highly anisotropic and inhomogeneously oriented fiber network of collagens; and an interstitial electrolytic fluid. We propose a new 3D finite strain constitutive model capable of simultaneously addressing both solid (reinforcement) and fluid (permeability) dependence of the tissue's mechanical response on the patient-specific collagen fiber network. To represent fiber reinforcement, we integrate the strain energies of single collagen fibers-weighted by an orientation distribution function (ODF) defined over a unit sphere-over the distributed fiber orientations in 3D. We define the anisotropic intrinsic permeability of the tissue with a structure tensor based again on the integration of the local ODF over all spatial fiber orientations. By design, our modeling formulation accepts structural data on patient-specific collagen fiber networks as determined via diffusion tensor MRI. We implement our new model in 3D large strain finite elements and study the distributions of interstitial fluid pressure, fluid pressure load support and shear stress within a cartilage sample under indentation. Results show that the fiber network dramatically increases interstitial fluid pressure and focuses it near the surface. Inhomogeneity in the tissue's composition also increases fluid pressure and reduces shear stress in the solid. Finally, a biphasic neo-Hookean material model, as is available in commercial finite element codes, does not capture important features of the intra-tissue response, e.g., distributions of interstitial fluid pressure and principal shear stress.

  17. Incorporating Retention Time to Refine Models Predicting Thermal Regimes of Stream Networks Across New England

    Science.gov (United States)

    Thermal regimes are a critical factor in models predicting effects of watershed management activities on fish habitat suitability. We have assembled a database of lotic temperature time series across New England (> 7000 station-year combinations) from state and Federal data s...

  18. Incorporating Parameter Uncertainty in Bayesian Segmentation Models: Application to Hippocampal Subfield Volumetry

    DEFF Research Database (Denmark)

    Iglesias, J. E.; Sabuncu, M. R.; Van Leemput, Koen

    2012-01-01

    Many successful segmentation algorithms are based on Bayesian models in which prior anatomical knowledge is combined with the available image information. However, these methods typically have many free parameters that are estimated to obtain point estimates only, whereas a faithful Bayesian anal...

  19. Teaching Note--Incorporating Journal Clubs into Social Work Education: An Exploratory Model

    Science.gov (United States)

    Moore, Megan; Fawley-King, Kya; Stone, Susan I.; Accomazzo, Sarah M.

    2013-01-01

    This article outlines the implementation of a journal club for master's and doctoral social work students interested in mental health practice. It defines educational journal clubs and discusses the history of journal clubs in medical education and the applicability of the model to social work education. The feasibility of implementing…

  20. Teaching for Art Criticism: Incorporating Feldman's Critical Analysis Learning Model in Students' Studio Practice

    Science.gov (United States)

    Subramaniam, Maithreyi; Hanafi, Jaffri; Putih, Abu Talib

    2016-01-01

    This study adopted 30 first year graphic design students' artwork, with critical analysis using Feldman's model of art criticism. Data were analyzed quantitatively; descriptive statistical techniques were employed. The scores were viewed in the form of mean score and frequencies to determine students' performances in their critical ability.…

  1. Improved Path Loss Simulation Incorporating Three-Dimensional Terrain Model Using Parallel Coprocessors

    Directory of Open Access Journals (Sweden)

    Zhang Bin Loo

    2017-01-01

    Full Text Available Current network simulators abstract out wireless propagation models due to the high computation requirements for realistic modeling. As such, there is still a large gap between the results obtained from simulators and real world scenario. In this paper, we present a framework for improved path loss simulation built on top of an existing network simulation software, NS-3. Different from the conventional disk model, the proposed simulation also considers the diffraction loss computed using Epstein and Peterson’s model through the use of actual terrain elevation data to give an accurate estimate of path loss between a transmitter and a receiver. The drawback of high computation requirements is relaxed by offloading the computationally intensive components onto an inexpensive off-the-shelf parallel coprocessor, which is a NVIDIA GPU. Experiments are performed using actual terrain elevation data provided from United States Geological Survey. As compared to the conventional CPU architecture, the experimental result shows that a speedup of 20x to 42x is achieved by exploiting the parallel processing of GPU to compute the path loss between two nodes using terrain elevation data. The result shows that the path losses between two nodes are greatly affected by the terrain profile between these two nodes. Besides this, the result also suggests that the common strategy to place the transmitter in the highest position may not always work.

  2. A Probabilistic Model of Visual Working Memory: Incorporating Higher Order Regularities into Working Memory Capacity Estimates

    Science.gov (United States)

    Brady, Timothy F.; Tenenbaum, Joshua B.

    2013-01-01

    When remembering a real-world scene, people encode both detailed information about specific objects and higher order information like the overall gist of the scene. However, formal models of change detection, like those used to estimate visual working memory capacity, assume observers encode only a simple memory representation that includes no…

  3. Incorporating Lightning Flash Data into the WRF-CMAQ Modeling System: Algorithms and Evaluations

    Science.gov (United States)

    We describe the use of lightning flash data from the National Lightning Detection Network (NLDN) to constrain and improve the performance of coupled meteorology-chemistry models. We recently implemented a scheme in which lightning data is used to control the triggering of conve...

  4. A quantitative model of the cardiac ventricular cell incorporating the transverse-axial tubular system

    Czech Academy of Sciences Publication Activity Database

    Pásek, Michal; Christé, G.; Šimurda, J.

    2003-01-01

    Roč. 22, č. 3 (2003), s. 355-368 ISSN 0231-5882 R&D Projects: GA ČR GP204/02/D129 Institutional research plan: CEZ:AV0Z2076919 Keywords : cardiac cell * tubular system * quantitative modelling Subject RIV: BO - Biophysics Impact factor: 0.794, year: 2003

  5. A Model for the Incorporation of the Traditional Healers into the ...

    African Journals Online (AJOL)

    In South Africa the patient uses both the traditional healers and biomedical personnel's services out of need for the best healing therapy to fulfil his/ her health needs. Failure of ... Data was analysed and the results of phase one as well as initial literature review were used to construct a conceptual framework for the model.

  6. Decision model incorporating utility theory and measurement of social values applied to nuclear waste management

    International Nuclear Information System (INIS)

    Litchfield, J.W.; Hansen, J.V.; Beck, L.C.

    1975-07-01

    A generalized computer-based decision analysis model was developed and tested. Several alternative concepts for ultimate disposal have already been developed; however, significant research is still required before any of these can be implemented. To make a choice based on technical estimates of the costs, short-term safety, long-term safety, and accident detection and recovery requires estimating the relative importance of each of these factors or attributes. These relative importance estimates primarily involve social values and therefore vary from one individual to the next. The approach used was to sample various public groups to determine the relative importance of each of the factors to the public. These estimates of importance weights were combined in a decision analysis model with estimates, furnished by technical experts, of the degree to which each alternative concept achieves each of the criteria. This model then integrates the two separate and unique sources of information and provides the decision maker with information as to the preferences and concerns of the public as well as the technical areas within each concept which need further research. The model can rank the alternatives using sampled public opinion and techno-economic data. This model provides a decision maker with a structured approach to subdividing complex alternatives into a set of more easily considered attributes, measuring the technical performance of each alternative relative to each attribute, estimating relevant social values, and assimilating quantitative information in a rational manner to estimate total value for each alternative. Because of the explicit nature of this decision analysis, the decision maker can select a specific alternative supported by clear documentation and justification for his assumptions and estimates. (U.S.)

  7. A multi-component model of the developing retinocollicular pathway incorporating axonal and synaptic growth.

    Directory of Open Access Journals (Sweden)

    Keith B Godfrey

    2009-12-01

    Full Text Available During development, neurons extend axons to different brain areas and produce stereotypical patterns of connections. The mechanisms underlying this process have been intensively studied in the visual system, where retinal neurons form retinotopic maps in the thalamus and superior colliculus. The mechanisms active in map formation include molecular guidance cues, trophic factor release, spontaneous neural activity, spike-timing dependent plasticity (STDP, synapse creation and retraction, and axon growth, branching and retraction. To investigate how these mechanisms interact, a multi-component model of the developing retinocollicular pathway was produced based on phenomenological approximations of each of these mechanisms. Core assumptions of the model were that the probabilities of axonal branching and synaptic growth are highest where the combined influences of chemoaffinity and trophic factor cues are highest, and that activity-dependent release of trophic factors acts to stabilize synapses. Based on these behaviors, model axons produced morphologically realistic growth patterns and projected to retinotopically correct locations in the colliculus. Findings of the model include that STDP, gradient detection by axonal growth cones and lateral connectivity among collicular neurons were not necessary for refinement, and that the instructive cues for axonal growth appear to be mediated first by molecular guidance and then by neural activity. Although complex, the model appears to be insensitive to variations in how the component developmental mechanisms are implemented. Activity, molecular guidance and the growth and retraction of axons and synapses are common features of neural development, and the findings of this study may have relevance beyond organization in the retinocollicular pathway.

  8. Butter as a feedstock for biodiesel production.

    Science.gov (United States)

    Haas, Michael J; Adawi, Nadia; Berry, William W; Feldman, Elaine; Kasprzyk, Stephen; Ratigan, Brian; Scott, Karen; Landsburg, Emily Bockian

    2010-07-14

    Fatty acid methyl esters (FAME) were produced from cow's milk (Bostaurus) butter by esterification/transesterification in the presence of methanol. The product was assayed according to the Standard Specification for Biodiesel Fuel Blend Stock (B100) for Middle Distillate Fuels (ASTM D 6751). The preparation failed to meet the specifications for flash point, free and total glycerin contents, total sulfur, and oxidation stability. Failures to meet the flash point and free/total glycerin specifications were determined to be due to interference with standard assays for these parameters by short-chain-length fatty acid esters. The oxidation stability of the butterfat FAME was improved by supplementation with a commercial antioxidant formulation. Approximately 725 ppm of antioxidant was required to meet the ASTM-specified stability value for biodiesel. This work indicates that, without further purification to reduce a slightly excessive sulfur content, fatty acid ester preparations produced from butter are unacceptable as sole components of a biodiesel fuel. However, it is possible that even without further purification a butter-based ester preparation could be mixed with biodiesel from other feedstocks to produce a blend that meets the current quality standards for biodiesel. The results presented here also illustrate some potential weaknesses in the accepted methods for biodiesel characterization when employed in the analysis of FAME preparations containing mid- and short-chain fatty acid esters.

  9. DEM Investigation of Particle-Scale Mechanical Properties of Frozen Soil Based on the Nonlinear Microcontact Model Incorporating Rolling Resistance

    Directory of Open Access Journals (Sweden)

    Lingshi An

    2018-01-01

    Full Text Available Although frozen soil is in nature the discrete material, it is generally treated as the continuum material. The mechanical properties of frozen soil are so complex to describe adequately by conventional continuum mechanics method. In this study, the nonlinear microcontact model incorporating rolling resistance is proposed to investigate the particle-scale mechanical properties of frozen soil. The failure mechanism of frozen soil is explicated based on the evolution of contact force chains and propagation of microcracks. In addition, the effects of contact stiffness ratio and friction coefficient on stress-strain curve and energy evolution are evaluated. The results show that the nonlinear microcontact model incorporating rolling resistance can better describe the experimental data. At a higher axial strain, the contact force chains near shear band which can give rise to the soil arch effect rotate away from the shear band inclination but not so much as to become perpendicular to it. The propagation of microcracks can be divided into two phases. The stress-strain curve is strongly influenced by contact stiffness ratio. In addition, friction coefficient does not significantly affect the initial tangential modulus. Compared with frictional coefficient, the effect of contact stiffness ratio on stress-strain curve and energy evolution is greater.

  10. A density dependent delayed predator-prey model with Beddington-DeAngelis type function response incorporating a prey refuge

    Science.gov (United States)

    Tripathi, Jai Prakash; Abbas, Syed; Thakur, Manoj

    2015-05-01

    This paper describes a predator-prey model incorporating a prey refuge. The feeding rate of consumers (predators) per consumer (i.e. functional response) is considered to be of Beddington-DeAngelis type. The Beddington-DeAngelis functional response is similar to the Holling-type II functional response but contains an extra term describing mutual interference by predators. We investigate the role of prey refuge and degree of mutual interference among predators in the dynamics of system. The dynamics of the system is discussed mainly from the point of view of permanence and stability. We obtain conditions that affect the persistence of the system. Local and global asymptotic stability of various equilibrium solutions is explored to understand the dynamics of the model system. The global asymptotic stability of positive interior equilibrium solution is established using suitable Lyapunov functional. The dynamical behaviour of the delayed system is further analyzed through incorporating discrete type gestation delay of predator. It is found that Hopf bifurcation occurs when the delay parameter τ crosses some critical value. The analytical results found in the paper are illustrated with the help of numerical examples.

  11. Representation and Incorporation of Close Others' Responses: The RICOR Model of Social Influence.

    Science.gov (United States)

    Smith, Eliot R; Mackie, Diane M

    2015-08-03

    We propose a new model of social influence, which can occur spontaneously and in the absence of typically assumed motives. We assume that perceivers routinely construct representations of other people's experiences and responses (beliefs, attitudes, emotions, and behaviors), when observing others' responses or simulating the responses of unobserved others. Like representations made accessible by priming, these representations may then influence the process that generates perceivers' own responses, without intention or awareness, especially when there is a strong social connection to the other. We describe evidence for the basic properties and important moderators of this process, which distinguish it from other mechanisms such as informational, normative, or social identity influence. The model offers new perspectives on the role of others' values in producing cultural differences, the persistence and power of stereotypes, the adaptive reasons for being influenced by others' responses, and the impact of others' views about the self. © 2015 by the Society for Personality and Social Psychology, Inc.

  12. Finite-volume model for chemical vapor infiltration incorporating radiant heat transfer. Interim report

    Energy Technology Data Exchange (ETDEWEB)

    Smith, A.W.; Starr, T.L. [Georgia Institute of Technology, Atlanta, GA (United States). School of Materials Science and Engineering

    1995-05-01

    Most finite-volume thermal models account for the diffusion and convection of heat and may include volume heating. However, for certain simulation geometries, a large percentage of heat flux is due to thermal radiation. In this paper a finite-volume computational procedure for the simulation of heat transfer by conduction, convection and radiation in three dimensional complex enclosures is developed. The radiant heat transfer is included as a source term in each volume element which is derived by Monte Carlo ray tracing from all possible radiating and absorbing faces. The importance of radiative heat transfer is illustrated in the modeling of chemical vapor infiltration (CVI) of tubes. The temperature profile through the tube preform matches experimental measurements only when radiation is included. An alternative, empirical approach using an {open_quotes}effective{close_quotes} thermal conductivity for the gas space can match the initial temperature profile but does not match temperature changes that occur during preform densification.

  13. Incorporating imperfect detection into joint models of communites: A response to Warton et al.

    Science.gov (United States)

    Beissinger, Steven R.; Iknayan, Kelly J.; Guillera-Arroita, Gurutzeta; Zipkin, Elise; Dorazio, Robert; Royle, Andy; Kery, Marc

    2016-01-01

    Warton et al. [1] advance community ecology by describing a statistical framework that can jointly model abundances (or distributions) across many taxa to quantify how community properties respond to environmental variables. This framework specifies the effects of both measured and unmeasured (latent) variables on the abundance (or occurrence) of each species. Latent variables are random effects that capture the effects of both missing environmental predictors and correlations in parameter values among different species. As presented in Warton et al., however, the joint modeling framework fails to account for the common problem of detection or measurement errors that always accompany field sampling of abundance or occupancy, and are well known to obscure species- and community-level inferences.

  14. Incorporating single-side sparing in models for predicting parotid dose sparing in head and neck IMRT

    Energy Technology Data Exchange (ETDEWEB)

    Yuan, Lulin, E-mail: lulin.yuan@duke.edu; Wu, Q. Jackie; Yin, Fang-Fang; Yoo, David [Department of Radiation Oncology, Duke University Medical Center, Durham, North Carolina 27710 (United States); Jiang, Yuliang [Department of Radiation Oncology, Peking University Third Hospital, Beijing, China, 100191 (China); Ge, Yaorong [Department of Software and Information Systems, University of North Carolina at Charlotte, Charlotte, North Carolina 28223 (United States)

    2014-02-15

    Purpose: Sparing of single-side parotid gland is a common practice in head-and-neck (HN) intensity modulated radiation therapy (IMRT) planning. It is a special case of dose sparing tradeoff between different organs-at-risk. The authors describe an improved mathematical model for predicting achievable dose sparing in parotid glands in HN IMRT planning that incorporates single-side sparing considerations based on patient anatomy and learning from prior plan data. Methods: Among 68 HN cases analyzed retrospectively, 35 cases had physician prescribed single-side parotid sparing preferences. The single-side sparing model was trained with cases which had single-side sparing preferences, while the standard model was trained with the remainder of cases. A receiver operating characteristics (ROC) analysis was performed to determine the best criterion that separates the two case groups using the physician's single-side sparing prescription as ground truth. The final predictive model (combined model) takes into account the single-side sparing by switching between the standard and single-side sparing models according to the single-side sparing criterion. The models were tested with 20 additional cases. The significance of the improvement of prediction accuracy by the combined model over the standard model was evaluated using the Wilcoxon rank-sum test. Results: Using the ROC analysis, the best single-side sparing criterion is (1) the predicted median dose of one parotid is higher than 24 Gy; and (2) that of the other is higher than 7 Gy. This criterion gives a true positive rate of 0.82 and a false positive rate of 0.19, respectively. For the bilateral sparing cases, the combined and the standard models performed equally well, with the median of the prediction errors for parotid median dose being 0.34 Gy by both models (p = 0.81). For the single-side sparing cases, the standard model overestimates the median dose by 7.8 Gy on average, while the predictions by the combined

  15. Terrestrial Feedbacks Incorporated in Global Vegetation Models through Observed Trait-Environment Responses

    Science.gov (United States)

    Bodegom, P. V.

    2015-12-01

    Most global vegetation models used to evaluate climate change impacts rely on plant functional types to describe vegetation responses to environmental stresses. In a traditional set-up in which vegetation characteristics are considered constant within a vegetation type, the possibility to implement and infer feedback mechanisms are limited as feedback mechanisms will likely involve a changing expression of community trait values. Based on community assembly concepts, we implemented functional trait-environment relationships into a global dynamic vegetation model to quantitatively assess this feature. For the current climate, a different global vegetation distribution was calculated with and without the inclusion of trait variation, emphasizing the importance of feedbacks -in interaction with competitive processes- for the prevailing global patterns. These trait-environmental responses do, however, not necessarily imply adaptive responses of vegetation to changing conditions and may locally lead to a faster turnover in vegetation upon climate change. Indeed, when running climate projections, simulations with trait variation did not yield a more stable or resilient vegetation than those without. Through the different feedback expressions, global and regional carbon and water fluxes were -however- strongly altered. At a global scale, model projections suggest an increased productivity and hence an increased carbon sink in the next decades to come, when including trait variation. However, by the end of the century, a reduced carbon sink is projected. This effect is due to a downregulation of photosynthesis rates, particularly in the tropical regions, even when accounting for CO2-fertilization effects. Altogether, the various global model simulations suggest the critical importance of including vegetation functional responses to changing environmental conditions to grasp terrestrial feedback mechanisms at global scales in the light of climate change.

  16. Reliability constrained decision model for energy service provider incorporating demand response programs

    International Nuclear Information System (INIS)

    Mahboubi-Moghaddam, Esmaeil; Nayeripour, Majid; Aghaei, Jamshid

    2016-01-01

    Highlights: • The operation of Energy Service Providers (ESPs) in electricity markets is modeled. • Demand response as the cost-effective solution is used for energy service provider. • The market price uncertainty is modeled using the robust optimization technique. • The reliability of the distribution network is embedded into the framework. • The simulation results demonstrate the benefits of robust framework for ESPs. - Abstract: Demand response (DR) programs are becoming a critical concept for the efficiency of current electric power industries. Therefore, its various capabilities and barriers have to be investigated. In this paper, an effective decision model is presented for the strategic behavior of energy service providers (ESPs) to demonstrate how to participate in the day-ahead electricity market and how to allocate demand in the smart distribution network. Since market price affects DR and vice versa, a new two-step sequential framework is proposed, in which unit commitment problem (UC) is solved to forecast the expected locational marginal prices (LMPs), and successively DR program is applied to optimize the total cost of providing energy for the distribution network customers. This total cost includes the cost of purchased power from the market and distributed generation (DG) units, incentive cost paid to the customers, and compensation cost of power interruptions. To obtain compensation cost, the reliability evaluation of the distribution network is embedded into the framework using some innovative constraints. Furthermore, to consider the unexpected behaviors of the other market participants, the LMP prices are modeled as the uncertainty parameters using the robust optimization technique, which is more practical compared to the conventional stochastic approach. The simulation results demonstrate the significant benefits of the presented framework for the strategic performance of ESPs.

  17. Teaching For Art Criticism: Incorporating Feldman’s Critical Analysis Learning Model In Students’ Studio Practice

    OpenAIRE

    Maithreyi Subramaniam; Jaffri Hanafi; Abu Talib Putih

    2016-01-01

    This study adopted 30 first year graphic design students’ artwork, with critical analysis using Feldman’s model of art criticism. Data were analyzed quantitatively; descriptive statistical techniques were employed. The scores were viewed in the form of mean score and frequencies to determine students’ performances in their critical ability. Pearson Correlation Coefficient was used to find out the correlation between students’ studio practice and art critical ability scores. The...

  18. Incorporating Labour Market Frictions into an Optimising-Based Monetary Policy Model

    OpenAIRE

    Moyen, S.; Sahuc, J-G.

    2004-01-01

    This paper examines the effects of introducing a non Walrasian labour market into the "New Neoclassical Synthesis'' framework. A dynamic stochastic general equilibrium model is formulated, solved, and calibrated in order to evaluate its ability to replicate the main features of the Euro area economy. This framework allows us to study the effects of labour market rigidities, nominal rigidities, and other frictions to give account of the impact of monetary policy, technology, public spending, a...

  19. Extrapolation of extreme sea levels: incorporation of Over-Threshold-Modeling to the Joint Probability Method

    Science.gov (United States)

    Mazas, Franck; Hamm, Luc; Kergadallan, Xavier

    2013-04-01

    In France, the storm Xynthia of February 27-28th, 2010 reminded engineers and stakeholders of the necessity for an accurate estimation of extreme sea levels for the risk assessment in coastal areas. Traditionally, two main approaches exist for the statistical extrapolation of extreme sea levels: the direct approach performs a direct extrapolation on the sea level data, while the indirect approach carries out a separate analysis of the deterministic component (astronomical tide) and stochastic component (meteorological residual, or surge). When the tidal component is large compared with the surge one, the latter approach is known to perform better. In this approach, the statistical extrapolation is performed on the surge component then the distribution of extreme seal levels is obtained by convolution of the tide and surge distributions. This model is often referred to as the Joint Probability Method. Different models from the univariate extreme theory have been applied in the past for extrapolating extreme surges, in particular the Annual Maxima Method (AMM) and the r-largest method. In this presentation, we apply the Peaks-Over-Threshold (POT) approach for declustering extreme surge events, coupled with the Poisson-GPD model for fitting extreme surge peaks. This methodology allows a sound estimation of both lower and upper tails of the stochastic distribution, including the estimation of the uncertainties associated to the fit by computing the confidence intervals. After convolution with the tide signal, the model yields the distribution for the whole range of possible sea level values. Particular attention is paid to the necessary distinction between sea level values observed at a regular time step, such as hourly, and sea level events, such as those occurring during a storm. Extremal indexes for both surges and levels are thus introduced. This methodology will be illustrated with a case study at Brest, France.

  20. Absorbed dose evaluation based on a computational voxel model incorporating distinct cerebral structures

    Energy Technology Data Exchange (ETDEWEB)

    Brandao, Samia de Freitas; Trindade, Bruno; Campos, Tarcisio P.R. [Universidade Federal de Minas Gerais (UFMG), Belo Horizonte, MG (Brazil)]. E-mail: samiabrandao@gmail.com; bmtrindade@yahoo.com; campos@nuclear.ufmg.br

    2007-07-01

    Brain tumors are quite difficult to treat due to the collateral radiation damages produced on the patients. Despite of the improvements in the therapeutics protocols for this kind of tumor, involving surgery and radiotherapy, the failure rate is still extremely high. This fact occurs because tumors can not often be totally removed by surgery since it may produce some type of deficit in the cerebral functions. Radiotherapy is applied after the surgery, and both are palliative treatments. During radiotherapy the brain does not absorb the radiation dose in homogeneous way, because the various density and chemical composition of tissues involved. With the intention of evaluating better the harmful effects caused by radiotherapy it was developed an elaborated cerebral voxel model to be used in computational simulation of the irradiation protocols of brain tumors. This paper presents some structures function of the central nervous system and a detailed cerebral voxel model, created in the SISCODES program, considering meninges, cortex, gray matter, white matter, corpus callosum, limbic system, ventricles, hypophysis, cerebellum, brain stem and spinal cord. The irradiation protocol simulation was running in the MCNP5 code. The model was irradiated with photons beam whose spectrum simulates a linear accelerator of 6 MV. The dosimetric results were exported to SISCODES, which generated the isodose curves for the protocol. The percentage isodose curves in the brain are present in this paper. (author)

  1. Incorporating institutions and collective action into a sociohydrological model of flood resilience

    Science.gov (United States)

    Yu, David J.; Sangwan, Nikhil; Sung, Kyungmin; Chen, Xi; Merwade, Venkatesh

    2017-02-01

    Stylized sociohydrological models have mainly used social memory aspects such as community awareness or sensitivity to connect hydrologic change and social response. However, social memory alone does not satisfactorily capture the details of how human behavior is translated into collective action for water resources governance. Nor is it the only social mechanism by which the two-way feedbacks of sociohydrology can be operationalized. This study contributes toward bridging of this gap by developing a sociohydrological model of a flood resilience that includes two additional components: (1) institutions for collective action, and (2) connections to an external economic system. Motivated by the case of community-managed flood protection systems (polders) in coastal Bangladesh, we use the model to understand critical general features that affect long-term resilience of human-flood systems. Our findings suggest that occasional adversity can enhance long-term resilience. Allowing some hydrological variability to enter into the polder can increase its adaptive capacity for resilience through the preservation of social norm for collective action. Further, there are potential trade-offs associated with optimization of flood resistance through structural measures. By reducing sensitivity to floods, the system may become more fragile under the double impact of floods and economic change.

  2. Biotransformation model of neutral and weakly polar organic compounds in fish incorporating internal partitioning.

    Science.gov (United States)

    Kuo, Dave T F; Di Toro, Dominic M

    2013-08-01

    A model for whole-body in vivo biotransformation of neutral and weakly polar organic chemicals in fish is presented. It considers internal chemical partitioning and uses Abraham solvation parameters as reactivity descriptors. It assumes that only chemicals freely dissolved in the body fluid may bind with enzymes and subsequently undergo biotransformation reactions. Consequently, the whole-body biotransformation rate of a chemical is retarded by the extent of its distribution in different biological compartments. Using a randomly generated training set (n = 64), the biotransformation model is found to be: log (HLφfish ) = 2.2 (±0.3)B - 2.1 (±0.2)V - 0.6 (±0.3) (root mean square error of prediction [RMSE] = 0.71), where HL is the whole-body biotransformation half-life in days, φfish is the freely dissolved fraction in body fluid, and B and V are the chemical's H-bond acceptance capacity and molecular volume. Abraham-type linear free energy equations were also developed for lipid-water (Klipidw ) and protein-water (Kprotw ) partition coefficients needed for the computation of φfish from independent determinations. These were found to be 1) log Klipidw  = 0.77E - 1.10S - 0.47A - 3.52B + 3.37V + 0.84 (in Lwat /kglipid ; n = 248, RMSE = 0.57) and 2) log Kprotw  = 0.74E - 0.37S - 0.13A - 1.37B + 1.06V - 0.88 (in Lwat /kgprot ; n = 69, RMSE = 0.38), where E, S, and A quantify dispersive/polarization, dipolar, and H-bond-donating interactions, respectively. The biotransformation model performs well in the validation of HL (n = 424, RMSE = 0.71). The predicted rate constants do not exceed the transport limit due to circulatory flow. Furthermore, the model adequately captures variation in biotransformation rate between chemicals with varying log octanol-water partitioning coefficient, B, and V and exhibits high degree of independence from the choice of training chemicals. The

  3. Influence of reaction conditions and feedstock on hydrochar properties

    International Nuclear Information System (INIS)

    Guo, Shuqing; Dong, Xiangyuan; Wu, Tingting; Zhu, Caixia

    2016-01-01

    Highlights: • Models of hydrochar properties were established based on severity parameter. • Derivative methods were used to study the variation of hydrochar properties. • Water to biomass ratio has a significant effect on the hydrochar yield. • The curves of hydrochar properties can be divided into three stages. • The maximum variation rate of hydrochar properties for six samples is at severity of 5.8–6.4. - Abstract: Hydrothermal carbonization (HTC) is a biomass conversion process to produce a renewable solid fuel (hydrochar). The reaction conditions, such as temperature, time, and water/biomass ratio have key effects on hydrochar characteristics. However, it has not been fully investigated to establish and compare models of hydrochar properties (solid yield, carbon content and HHV) for different biomass HTC at different reaction conditions. These models and the corresponding analytical methods are favorable to optimize operating parameters and process design of HTC. In this work, HTC experiments from corn stalk, longan Shell and NaOH-pretreated longan Shell were carried out at 210 °C, 250 °C and 290 °C for 30 min, 240 min and 480 min with different water to biomass ratios. New models of the hydrochar properties of corn stalk, longan Shell and NaOH-pretreated longan Shell were established based on severity parameter (combined time and temperature) and dose-response function. Also, data of wood, olive stone and grape marc hydrochars (collected from literatures) were used for comparison. The first and second derivative methods were also employed to analyze and compare the variation of these hydrochar properties. The results showed that the hydrchar yield, carbon content, and HHV curves decrease monotonically and can be divided into three significant stages with increasing reaction severity. The water to biomass ratio has a significant effect on the hydrochar yield. With increasing the water to biomass ratio, both the maximum decrease rates and the

  4. Incorporation of lipophilic pathways into the porous pathway model for describing skin permeabilization during low-frequency sonophoresis.

    Science.gov (United States)

    Tezel, Ahmet; Sens, Ashley; Mitragotri, Samir

    2002-09-18

    Application of low-frequency sonophoresis (LFS) has been shown to increase skin permeability, thereby facilitating delivery of hydrophilic solutes. We have previously shown that the modified porous pathway model provides an adequate theoretical description of transdermal delivery of hydrophilic solutes through pores in the presence and absence of ultrasound. However, small hydrophilic solutes (M(w)<400 Da) that exhibit a moderate partition coefficient, K(o/w) (0.1incorporate the lipophilic pathway into the porous pathway model to describe transdermal drug transport in the absence and presence of ultrasound. Copyright 2002 Elsevier Science B.V.

  5. Incorporation of SemiSpan SuperSonic Transport (S4T) Aeroservoelastic Models into SAREC-ASV Simulation

    Science.gov (United States)

    Christhilf, David M.; Pototzky, Anthony S.; Stevens, William L.

    2010-01-01

    The Simulink-based Simulation Architecture for Evaluating Controls for Aerospace Vehicles (SAREC-ASV) was modified to incorporate linear models representing aeroservoelastic characteristics of the SemiSpan SuperSonic Transport (S4T) wind-tunnel model. The S4T planform is for a Technology Concept Aircraft (TCA) design from the 1990s. The model has three control surfaces and is instrumented with accelerometers and strain gauges. Control laws developed for wind-tunnel testing for Ride Quality Enhancement, Gust Load Alleviation, and Flutter Suppression System functions were implemented in the simulation. The simulation models open- and closed-loop response to turbulence and to control excitation. It provides time histories for closed-loop stable conditions above the open-loop flutter boundary. The simulation is useful for assessing the potential impact of closed-loop control rate and position saturation. It also provides a means to assess fidelity of system identification procedures by providing time histories for a known plant model, with and without unmeasured turbulence as a disturbance. Sets of linear models representing different Mach number and dynamic pressure conditions were implemented as MATLAB Linear Time Invariant (LTI) objects. Configuration changes were implemented by selecting which LTI object to use in a Simulink template block. A limited comparison of simulation versus wind-tunnel results is shown.

  6. Mathematical modeling of manganese adsorption onto bone char in a continuous fixed bed column incorporating backmixing and shriking core approaches

    Directory of Open Access Journals (Sweden)

    M. E. Maria

    Full Text Available Abstract The present study investigated the dynamics of manganese adsorption onto bone char in a continuous fixed bed column using a mathematical model that incorporates: (i the backmixing model to describe the fluid flow through the bed and (ii the shrinking core model to describe the kinetic and mass transfer phenomena within spherical adsorbent particles. The proposed model consists of an ordinary differential equation system. Hydrodynamic, kinetic and diffusive parameters were determined by fitting the mathematical model to the experimental data obtained by Sicupira et al. (2015. For the operating conditions evaluated in this study, the intraparticle diffusion represented the controlling step of the adsorption process (Bim> 3.8. The increase in the feed rate of the column (3.0-7.5 mL min-1 and the decrease in the height of the bed (8-16 cm resulted in a decrease in the time required for the saturation of the column bed. The model is flexible for a variety of flow conditions and adequately reproduced the behavior of the manganese adsorption process in the fixed bed column operation (R²> 0.99 with an average percentage error less than15%.

  7. The Eatwell Guide: Modelling the Health Implications of Incorporating New Sugar and Fibre Guidelines.

    Directory of Open Access Journals (Sweden)

    Linda J Cobiac

    Full Text Available To model population health impacts of dietary changes associated with the redevelopment of the UK food-based dietary guidelines (the 'Eatwell Guide'.Using multi-state lifetable methods, we modelled the impact of dietary changes on cardiovascular disease, diabetes and cancers over the lifetime of the current UK population. From this model, we determined change in life expectancy and disability-adjusted life years (DALYs that could be averted.Changing the average diet to that recommended in the new Eatwell Guide, without increasing total energy intake, could increase average life expectancy by 5.4 months (95% uncertainty interval: 4.7 to 6.2 for men and 4.0 months (3.4 to 4.6 for women; and avert 17.9 million (17.6 to 18.2 DALYs over the lifetime of the current population. A large proportion of the health benefits are from prevention of type 2 diabetes, with 440,000 (400,000 to 480,000 new cases prevented in men and 340,000 (310,000 to 370,000 new cases prevented in women, over the next ten years. Prevention of cardiovascular diseases and colorectal cancer is also large. However, if the diet recommended in the new Eatwell Guide is achieved with an accompanying increase in energy intake (and thus an increase in body mass index, around half the potential improvements in population health will not be realised.The dietary changes required to meet recommendations in the Eatwell Guide, which include eating more fruits and vegetables and less red and processed meats and dairy products, are large. However, the potential population health benefits are substantial.

  8. Dipole estimation errors due to not incorporating anisotropic conductivities in realistic head models for EEG source analysis

    International Nuclear Information System (INIS)

    Hallez, Hans; Staelens, Steven; Lemahieu, Ignace

    2009-01-01

    EEG source analysis is a valuable tool for brain functionality research and for diagnosing neurological disorders, such as epilepsy. It requires a geometrical representation of the human head or a head model, which is often modeled as an isotropic conductor. However, it is known that some brain tissues, such as the skull or white matter, have an anisotropic conductivity. Many studies reported that the anisotropic conductivities have an influence on the calculated electrode potentials. However, few studies have assessed the influence of anisotropic conductivities on the dipole estimations. In this study, we want to determine the dipole estimation errors due to not taking into account the anisotropic conductivities of the skull and/or brain tissues. Therefore, head models are constructed with the same geometry, but with an anisotropically conducting skull and/or brain tissue compartment. These head models are used in simulation studies where the dipole location and orientation error is calculated due to neglecting anisotropic conductivities of the skull and brain tissue. Results show that not taking into account the anisotropic conductivities of the skull yields a dipole location error between 2 and 25 mm, with an average of 10 mm. When the anisotropic conductivities of the brain tissues are neglected, the dipole location error ranges between 0 and 5 mm. In this case, the average dipole location error was 2.3 mm. In all simulations, the dipole orientation error was smaller than 10 deg. We can conclude that the anisotropic conductivities of the skull have to be incorporated to improve the accuracy of EEG source analysis. The results of the simulation, as presented here, also suggest that incorporation of the anisotropic conductivities of brain tissues is not necessary. However, more studies are needed to confirm these suggestions.

  9. Procurement-distribution model for perishable items with quantity discounts incorporating freight policies under fuzzy environment

    Directory of Open Access Journals (Sweden)

    Makkar Sandhya

    2013-01-01

    Full Text Available A significant issue of the supply chain problem is how to integrate different entities. Managing supply chain is a difficult task because of complex integrations, especially when the products are perishable in nature. Little attention has been paid on ordering specific perishable products jointly in uncertain environment with multiple sources and multiple destinations. In this article, we propose a supply chain coordination model through quantity and freight discount policy for perishable products under uncertain cost and demand information. A case is provided to validate the procedure.

  10. A Compliant Bistable Mechanism Design Incorporating Elastica Buckling Beam Theory and Pseudo-Rigid-Body Model

    DEFF Research Database (Denmark)

    Sönmez, Ümit; Tutum, Cem Celal

    2008-01-01

    In this work, a new compliant bistable mechanism design is introduced. The combined use of pseudo-rigid-body model (PRBM) and the Elastica buckling theory is presented for the first time to analyze the new design. This mechanism consists of the large deflecting straight beams, buckling beams......, and a slider. The kinematic analysis of this new mechanism is studied, using nonlinear Elastica buckling beam theory, the PRBM of a large deflecting cantilever beam, the vector loop closure equations, and numerically solving nonlinear algebraic equations. A design method of the bistable mechanism...

  11. Cargill Incorporated

    Science.gov (United States)

    Cargill, Incorporated, 518 East Fourth Street, Watkins Glen, New York 14891 has applied to the U.S. Environmental Protection Agency (EPA) under the provisions of the Safe Drinking Water Act, 42 U.S.C. 300f et. seq (the Act), for a new Underground Injection

  12. The New Zealand gravimetric quasigeoid model 2017 that incorporates nationwide airborne gravimetry

    Science.gov (United States)

    McCubbine, J. C.; Amos, M. J.; Tontini, F. C.; Smith, E.; Winefied, R.; Stagpoole, V.; Featherstone, W. E.

    2017-12-01

    A one arc-minute resolution gravimetric quasigeoid model has been computed for New Zealand, covering the region 25°S -60°S and 160°E -170°W . It was calculated by Wong and Gore modified Stokes integration using the remove-compute-restore technique with the EIGEN-6C4 global gravity model as the reference field. The gridded gravity data used for the computation consisted of 40,677 land gravity observations, satellite altimetry-derived marine gravity anomalies, historical shipborne marine gravity observations and, importantly, approximately one million new airborne gravity observations. The airborne data were collected with the specific intention of reinforcing the shortcomings of the existing data in areas of rough topography inaccessible to land gravimetry and in coastal areas where shipborne gravimetry cannot be collected and altimeter-derived gravity anomalies are generally poor. The new quasigeoid has a nominal precision of ± 48 mm on comparison with GPS-levelling data, which is approximately 14 mm less than its predecessor NZGeoid09.

  13. An arbitrary boundary with ghost particles incorporated in coupled FEM-SPH model for FSI problems

    Science.gov (United States)

    Long, Ting; Hu, Dean; Wan, Detao; Zhuang, Chen; Yang, Gang

    2017-12-01

    It is important to treat the arbitrary boundary of Fluid-Structure Interaction (FSI) problems in computational mechanics. In order to ensure complete support condition and restore the first-order consistency near the boundary of Smoothed Particle Hydrodynamics (SPH) method for coupling Finite Element Method (FEM) with SPH model, a new ghost particle method is proposed by dividing the interceptive area of kernel support domain into subareas corresponding to boundary segments of structure. The ghost particles are produced automatically for every fluid particle at each time step, and the properties of ghost particles, such as density, mass and velocity, are defined by using the subareas to satisfy the boundary condition. In the coupled FEM-SPH model, the normal and shear forces from a boundary segment of structure to a fluid particle are calculated through the corresponding ghost particles, and its opposite forces are exerted on the corresponding boundary segment, then the momentum of the present method is conservation and there is no matching requirements between the size of elements and the size of particles. The performance of the present method is discussed and validated by several FSI problems with complex geometry boundary and moving boundary.

  14. A hierarchical Bayesian model to incorporate uncertainty into methods for diversity partitioning.

    Science.gov (United States)

    Marion, Zachary H; Fordyce, James A; Fitzpatrick, Benjamin M

    2018-04-01

    Recently there have been major theoretical advances in the quantification and partitioning of diversity within and among communities, regions, and ecosystems. However, applying those advances to real data remains a challenge. Ecologists often end up describing their samples rather than estimating the diversity components of an underlying study system, and existing approaches do not easily provide statistical frameworks for testing ecological questions. Here we offer one avenue to do all of the above using a hierarchical Bayesian approach. We estimate posterior distributions of the underlying "true" relative abundances of each species within each unit sampled. These posterior estimates of relative abundance can then be used with existing formulae to estimate and partition diversity. The result is a posterior distribution of diversity metrics describing our knowledge (or beliefs) about the study system. This approach intuitively leads to statistical inferences addressing biologically motivated hypotheses via Bayesian model comparison. Using simulations, we demonstrate that our approach does as well or better at approximating the "true" diversity of a community relative to naïve or ad-hoc bias-corrected estimates. Moreover, model comparison correctly distinguishes between alternative hypotheses about the distribution of diversity within and among samples. Finally, we use an empirical ecological dataset to illustrate how the approach can be used to address questions about the makeup and diversities of assemblages at local and regional scales. © 2018 by the Ecological Society of America.

  15. Bibliography on Biomass Feedstock Research: 1978-2002

    Energy Technology Data Exchange (ETDEWEB)

    Cushman, J.H.

    2003-05-01

    This report provides bibliographic citations for more than 1400 reports on biomass feedstock development published by Oak Ridge National Laboratory and its collaborators from 1978 through 2002. Oak Ridge National Laboratory is engaged in analysis of biomass resource supplies, research on the sustainability of feedstock resources, and research on feedstock engineering and infrastructure. From 1978 until 2002, Oak Ridge National Laboratory also provided technical leadership for the U.S. Department of Energy's Bioenergy Feedstock Development Program (BFDP), which supported research to identify and develop promising energy crops. This bibliography lists reports published by Oak Ridge National Laboratory and by its collaborators in the BFDP, including graduate student theses and dissertations.

  16. Biodiesel From Alternative Oilseed Feedstocks: Production and Properties

    Science.gov (United States)

    Fatty acid methyl esters were prepared and evaluated as potential biodiesel fuels from several alternative oilseed feedstocks, which included camelina (Camelina sativa L.), coriander (Coriandrum sativum L.), field mustard (Brassica juncea L.), field pennycress (Thlaspi arvense L.), and meadowfoam (L...

  17. Feedstock and Conversion Supply System Design and Analysis

    Energy Technology Data Exchange (ETDEWEB)

    Jacobson, J. [Idaho National Lab. (INL), Idaho Falls, ID (United States); Mohammad, R. [Idaho National Lab. (INL), Idaho Falls, ID (United States); Cafferty, K. [Idaho National Lab. (INL), Idaho Falls, ID (United States); Kenney, K. [Idaho National Lab. (INL), Idaho Falls, ID (United States); Searcy, E. [Idaho National Lab. (INL), Idaho Falls, ID (United States); Hansen, J. [Idaho National Lab. (INL), Idaho Falls, ID (United States)

    2014-09-01

    The success of the earlier logistic pathway designs (Biochemical and Thermochemical) from a feedstock perspective was that it demonstrated that through proper equipment selection and best management practices, conventional supply systems (referred to in this report as “conventional designs,” or specifically the 2012 Conventional Design) can be successfully implemented to address dry matter loss, quality issues, and enable feedstock cost reductions that help to reduce feedstock risk of variable supply and quality and enable industry to commercialize biomass feedstock supply chains. The caveat of this success is that conventional designs depend on high density, low-cost biomass with no disruption from incremental weather. In this respect, the success of conventional designs is tied to specific, highly productive regions such as the southeastern U.S. which has traditionally supported numerous pulp and paper industries or the Midwest U.S for corn stover.

  18. Reclaimable Thermally Reversible Polymers for AM Feedstock, Phase II

    Data.gov (United States)

    National Aeronautics and Space Administration — CRG proposes to continue efforts from the 2016 NASA SBIR Phase I topic H5.04 Reclaimable Thermally Reversible Polymers for AM Feedstock. In Phase II, CRG will refine...

  19. The effect of intra-abdominal hypertension incorporating severe acute pancreatitis in a porcine model.

    Directory of Open Access Journals (Sweden)

    Lu Ke

    Full Text Available INTRODUCTION: Abdominal compartment syndrome (ACS and intra abdominal hypertension(IAH are common clinical findings in patients with severe acute pancreatitis(SAP. It is thought that an increased intra abdominal pressure(IAP is associated with poor prognosis in SAP patients. But the detailed effect of IAH/ACS on different organ system is not clear. The aim of this study was to assess the effect of SAP combined with IAH on hemodynamics, systemic oxygenation, and organ damage in a 12 h lasting porcine model. MEASUREMENTS AND METHODS: Following baseline registrations, a total of 30 animals were divided into 5 groups (6 animals in each group: SAP+IAP30 group, SAP+IAP20 group, SAP group, IAP30 group(sham-operated but without SAP and sham-operated group. We used a N(2 pneumoperitoneum to induce different levels of IAH and retrograde intra-ductal infusion of sodium taurocholate to induce SAP. The investigation period was 12 h. Hemodynamic parameters (CO, HR, MAP, CVP, urine output, oxygenation parameters(e.g., S(vO(2, PO(2, PaCO(2, peak inspiratory pressure, as well as serum parameters (e.g., ALT, amylase, lactate, creatinine were recorded. Histological examination of liver, intestine, pancreas, and lung was performed. MAIN RESULTS: Cardiac output significantly decreased in the SAP+IAH animals compared with other groups. Furthermore, AST, creatinine, SUN and lactate showed similar increasing tendency paralleled with profoundly decrease in S(vO(2. The histopathological analyses also revealed higher grade injury of liver, intestine, pancreas and lung in the SAP+IAH groups. However, few differences were found between the two SAP+IAH groups with different levels of IAP. CONCLUSIONS: Our newly developed porcine SAP+IAH model demonstrated that there were remarkable effects on global hemodynamics, oxygenation and organ function in response to sustained IAH of 12 h combined with SAP. Moreover, our model should be helpful to study the mechanisms of IAH

  20. Etoposide incorporated into camel milk phospholipids liposomes shows increased activity against fibrosarcoma in a mouse model.

    Science.gov (United States)

    Maswadeh, Hamzah M; Aljarbou, Ahmad N; Alorainy, Mohammed S; Alsharidah, Mansour S; Khan, Masood A

    2015-01-01

    Phospholipids were isolated from camel milk and identified by using high performance liquid chromatography and gas chromatography-mass spectrometry (GC/MS). Anticancer drug etoposide (ETP) was entrapped in liposomes, prepared from camel milk phospholipids, to determine its activity against fibrosarcoma in a murine model. Fibrosarcoma was induced in mice by injecting benzopyrene (BAP) and tumor-bearing mice were treated with various formulations of etoposide, including etoposide entrapped camel milk phospholipids liposomes (ETP-Cam-liposomes) and etoposide-loaded DPPC-liposomes (ETP-DPPC-liposomes). The tumor-bearing mice treated with ETP-Cam-liposomes showed slow progression of tumors and increased survival compared to free ETP or ETP-DPPC-liposomes. These results suggest that ETP-Cam-liposomes may prove to be a better drug delivery system for anticancer drugs.

  1. Etoposide Incorporated into Camel Milk Phospholipids Liposomes Shows Increased Activity against Fibrosarcoma in a Mouse Model

    Directory of Open Access Journals (Sweden)

    Hamzah M. Maswadeh

    2015-01-01

    Full Text Available Phospholipids were isolated from camel milk and identified by using high performance liquid chromatography and gas chromatography-mass spectrometry (GC/MS. Anticancer drug etoposide (ETP was entrapped in liposomes, prepared from camel milk phospholipids, to determine its activity against fibrosarcoma in a murine model. Fibrosarcoma was induced in mice by injecting benzopyrene (BAP and tumor-bearing mice were treated with various formulations of etoposide, including etoposide entrapped camel milk phospholipids liposomes (ETP-Cam-liposomes and etoposide-loaded DPPC-liposomes (ETP-DPPC-liposomes. The tumor-bearing mice treated with ETP-Cam-liposomes showed slow progression of tumors and increased survival compared to free ETP or ETP-DPPC-liposomes. These results suggest that ETP-Cam-liposomes may prove to be a better drug delivery system for anticancer drugs.

  2. Teaching For Art Criticism: Incorporating Feldman’s Critical Analysis Learning Model In Students’ Studio Practice

    Directory of Open Access Journals (Sweden)

    Maithreyi Subramaniam

    2016-01-01

    Full Text Available This study adopted 30 first year graphic design students’ artwork, with critical analysis using Feldman’s model of art criticism. Data were analyzed quantitatively; descriptive statistical techniques were employed. The scores were viewed in the form of mean score and frequencies to determine students’ performances in their critical ability. Pearson Correlation Coefficient was used to find out the correlation between students’ studio practice and art critical ability scores. The findings showed most students performed slightly better than average in the critical analyses and performed best in selecting analysis among the four dimensions assessed. In the context of the students’ studio practice and critical ability, findings showed there are some connections between the students’ art critical ability and studio practice.

  3. Growth kinetics and morphology of a ballistic deposition model that incorporates surface diffusion for two species

    International Nuclear Information System (INIS)

    El-Nashar, H.F.; Cerdeira, H.A.

    1998-08-01

    We introduce a ballistic deposition model for two kinds of particles (active and inactive) in (2+1) dimensions upon introducing the surface diffusion for the inactive particles. A morphological structural transition is found as the probability of being the inactive particle increases. This transition is well defined by the change in the behavior of the surface width when it is plotted versus time and probability. The exponents α and β calculated for different values of probability show the same behavior. The presence of both types of particles issues three different processes that control the growing surface: overhanging, nonlocal growth and diffusion. It finally leads to a morphological structural transition where the universality changes away from that of Kardar-Parisi-Zhang, in (2+1) dimensions, but not into Edwards-Wilkinson's. (author)

  4. Incorporating numerical modeling into estimates of the detection capability of the IMS infrasound network

    Science.gov (United States)

    Le Pichon, A.; Ceranna, L.; Vergoz, J.

    2012-03-01

    To monitor compliance with the Comprehensive Nuclear-Test ban Treaty (CTBT), a dedicated International Monitoring System (IMS) is being deployed. Recent global scale observations recorded by this network confirm that its detection capability is highly variable in space and time. Previous studies estimated the radiated source energy from remote observations using empirical yield-scaling relations which account for the along-path stratospheric winds. Although the empirical wind correction reduces the variance in the explosive energy versus pressure relationship, strong variability remains in the yield estimate. Today, numerical modeling techniques provide a basis to better understand the role of different factors describing the source and the atmosphere that influence propagation predictions. In this study, the effects of the source frequency and the stratospheric wind speed are simulated. In order to characterize fine-scale atmospheric structures which are excluded from the current atmospheric specifications, model predictions are further enhanced by the addition of perturbation terms. A theoretical attenuation relation is thus developed from massive numerical simulations using the Parabolic Equation method. Compared with previous studies, our approach provides a more realistic physical description of long-range infrasound propagation. We obtain a new relation combining a near-field and a far-field term, which account for the effects of both geometrical spreading and absorption. In the context of the future verification of the CTBT, the derived attenuation relation quantifies the spatial and temporal variability of the IMS infrasound network performance in higher resolution, and will be helpful for the design and prioritizing maintenance of any arbitrary infrasound monitoring network.

  5. An evaluation of a paediatric radiation oncology teaching programme incorporating a SCORPIO teaching model

    International Nuclear Information System (INIS)

    Ahern, Verity

    2011-01-01

    Full text: Many radiation oncology registrars have no exposure to paedi atrics during their training, To address this, the Paediatric Special Interest Group of the Royal Australian and New Zealand College of Radiologists has convened a biennial teaching course since 1997. The 2009 course incorpo rated the use of a Structured, Clinical, Objective-Referenced, Problem orientated, Integrated and Organized (SCORPIO) teaching model for small group tutorials. This study evaluates whether the paediatric radiation oncol ogy curriculum can be adapted to the SCORPIO teaching model and to evaluate the revised course from the registrars' perspective. Methods: Teaching and learning resources included a pre-course reading list, a lecture series programme and a SCORPIO workshop. Three evaluation instruments were developed: an overall Course Evaluation Survey for all participants, a SCORPIO Workshop Survey for registrars and a Teacher's SCORPIO Workshop Survey. Results: Forty-five radiation oncology registrars, 14 radiation therapists and five paediatric oncology registrars attended. Seventy-three per cent (47/64) of all participants completed the Course Evaluation Survey and 95% (38/40) of registrars completed the SCORPIO Workshop Survey. All teachers com pleted the Teacher's SCORPIO Survey (10/10). The overall educational expe rience was rated as good or excellent by 93% (43/47) of respondents. Ratings of satisfaction with lecture sessions were predominantly good or excellent. Registrars gave the SCORPIO workshop high ratings on each of 10 aspects of quality, with 82% allocating an excellent rating overall for the SCORPIO activity. Both registrars and teachers recommended more time for the SCORPIO stations. Conclusions: The 2009 course met the educational needs of the radiation oncology registrars and the SCORPIO workshop was a highly valued educa tional component.

  6. Modeling of Compressive Strength for Self-Consolidating High-Strength Concrete Incorporating Palm Oil Fuel Ash

    Science.gov (United States)

    Safiuddin, Md.; Raman, Sudharshan N.; Abdus Salam, Md.; Jumaat, Mohd. Zamin

    2016-01-01

    Modeling is a very useful method for the performance prediction of concrete. Most of the models available in literature are related to the compressive strength because it is a major mechanical property used in concrete design. Many attempts were taken to develop suitable mathematical models for the prediction of compressive strength of different concretes, but not for self-consolidating high-strength concrete (SCHSC) containing palm oil fuel ash (POFA). The present study has used artificial neural networks (ANN) to predict the compressive strength of SCHSC incorporating POFA. The ANN model has been developed and validated in this research using the mix proportioning and experimental strength data of 20 different SCHSC mixes. Seventy percent (70%) of the data were used to carry out the training of the ANN model. The remaining 30% of the data were used for testing the model. The training of the ANN model was stopped when the root mean square error (RMSE) and the percentage of good patterns was 0.001 and ≈100%, respectively. The predicted compressive strength values obtained from the trained ANN model were much closer to the experimental values of compressive strength. The coefficient of determination (R2) for the relationship between the predicted and experimental compressive strengths was 0.9486, which shows the higher degree of accuracy of the network pattern. Furthermore, the predicted compressive strength was found very close to the experimental compressive strength during the testing process of the ANN model. The absolute and percentage relative errors in the testing process were significantly low with a mean value of 1.74 MPa and 3.13%, respectively, which indicated that the compressive strength of SCHSC including POFA can be efficiently predicted by the ANN. PMID:28773520

  7. Incorporating the CALPHAD sublattice approach of ordering into the phase-field model with finite interface dissipation

    International Nuclear Information System (INIS)

    Zhang, Lijun; Stratmann, Matthias; Du, Yong; Sundman, Bo; Steinbach, Ingo

    2015-01-01

    A new approach to incorporate the sublattice models in the CALPHAD (CALculation of PHAse Diagram) formalism directly into the phase-field formalism is developed. In binary alloys, the sublattice models can be classified into two types (i.e., “Type I” and “Type II”), depending on whether a direct one-to-one relation between the element site fraction in the CALPHAD database and the phase concentration in the phase-field model exists (Type I), or not (Type II). For “Type II” sublattice models, the specific site fractions, corresponding to a given mole fraction, have to be established via internal relaxation between different sublattices. Internal minimization of sublattice occupancy and solute evolution during microstructure transformation leads, in general, to a solution superior to the separate solution of the individual problems. The present coupling technique is validated for Fe–C and Ni–Al alloys. Finally, the model is extended into multicomponent alloys and applied to simulate the nucleation process of VC monocarbide from austenite matrix in a steel containing vanadium

  8. A battery model that fully couples mechanics and electrochemistry at both particle and electrode levels by incorporation of particle interaction

    Science.gov (United States)

    Wu, Bin; Lu, Wei

    2017-08-01

    This paper develops a multi-scale mechanical-electrochemical model which enables fully coupled mechanics and electrochemistry at both particle and electrode levels. At the particle level, solid diffusion is modeled using a generalized chemical potential to capture the effects of mechanical stress and phase transformation. At the electrode level, the stress arising from particle interaction is incorporated in a continuum model. This particle interaction stress is in addition to the traditional concept of intercalation stress inside isolated particles. The particle and continuum electrode levels are linked by the particle interaction stress as loads on the particle surface, and by consideration of stress on the electrochemical reaction rate on the particle surface. The effect of mechanical stress on electrochemical reaction results in a stress-dependent over-potential between particle and electrolyte. Stress gradient in an electrode leads to inhomogeneous intercalation/deintercalation currents for particles depending on their interaction stress with neighbors, resulting in stress gradient induced inhomogeneous state of charge. Conversely, non-uniform intercalation/deintercalation currents in an electrode lead to stress between particles. With this model we have an important finding: an electrochemically inactive region in an electrode causes stress built-up. This model provides a powerful tool to address various problems such as fracture in-between particles.

  9. Development of a model of a multi-lymphangion lymphatic vessel incorporating realistic and measured parameter values.

    Science.gov (United States)

    Bertram, C D; Macaskill, C; Davis, M J; Moore, J E

    2014-04-01

    Our published model of a lymphatic vessel consisting of multiple actively contracting segments between non-return valves has been further developed by the incorporation of properties derived from observations and measurements of rat mesenteric vessels. These included (1) a refractory period between contractions, (2) a highly nonlinear form for the passive part of the pressure-diameter relationship, (3) hysteretic and transmural-pressure-dependent valve opening and closing pressure thresholds and (4) dependence of active tension on muscle length as reflected in local diameter. Experimentally, lymphatic valves are known to be biased to stay open. In consequence, in the improved model, vessel pumping of fluid suffers losses by regurgitation, and valve closure is dependent on backflow first causing an adverse valve pressure drop sufficient to reach the closure threshold. The assumed resistance of an open valve therefore becomes a critical parameter, and experiments to measure this quantity are reported here. However, incorporating this parameter value, along with other parameter values based on existing measurements, led to ineffective pumping. It is argued that the published measurements of valve-closing pressure threshold overestimate this quantity owing to neglect of micro-pipette resistance. An estimate is made of the extent of the possible resulting error. Correcting by this amount, the pumping performance is improved, but still very inefficient unless the open-valve resistance is also increased beyond the measured level. Arguments are given as to why this is justified, and other areas where experimental data are lacking are identified. The model is capable of future adaptation as new experimental data appear.

  10. Modelling how incorporation of divalent cations affects calcite wettability-implications for biomineralisation and oil recovery

    Science.gov (United States)

    Andersson, M. P.; Dideriksen, K.; Sakuma, H.; Stipp, S. L. S.

    2016-06-01

    Using density functional theory and geochemical speciation modelling, we predicted how solid-fluid interfacial energy is changed, when divalent cations substitute into a calcite surface. The effect on wettability can be dramatic. Trace metal uptake can impact organic compound adsorption, with effects for example, on the ability of organisms to control crystal growth and our ability to predict the wettability of pore surfaces. Wettability influences how easily an organic phase can be removed from a surface, either organic compounds from contaminated soil or crude oil from a reservoir. In our simulations, transition metals substituted exothermically into calcite and more favourably into sites at the surface than in the bulk, meaning that surface properties are more strongly affected than results from bulk experiments imply. As a result of divalent cation substitution, calcite-fluid interfacial energy is significantly altered, enough to change macroscopic contact angle by tens of degrees. Substitution of Sr, Ba and Pb makes surfaces more hydrophobic. With substitution of Mg and the transition metals, calcite becomes more hydrophilic, weakening organic compound adsorption. For biomineralisation, this provides a switch for turning on and off the activity of organic crystal growth inhibitors, thereby controlling the shape of the associated mineral phase.

  11. Incorporating the gut microbiota into models of human and non-human primate ecology and evolution.

    Science.gov (United States)

    Amato, Katherine R

    2016-01-01

    The mammalian gut is home to a diverse community of microbes. Advances in technology over the past two decades have allowed us to examine this community, the gut microbiota, in more detail, revealing a wide range of influences on host nutrition, health, and behavior. These host-gut microbe interactions appear to shape host plasticity and fitness in a variety of contexts, and therefore represent a key factor missing from existing models of human and non-human primate ecology and evolution. However, current studies of the gut microbiota tend to include limited contextual data or are clinical, making it difficult to directly test broad anthropological hypotheses. Here, I review what is known about the animal gut microbiota and provide examples of how gut microbiota research can be integrated into the study of human and non-human primate ecology and evolution with targeted data collection. Specifically, I examine how the gut microbiota may impact primate diet, energetics, disease resistance, and cognition. While gut microbiota research is proliferating rapidly, especially in the context of humans, there remain important gaps in our understanding of host-gut microbe interactions that will require an anthropological perspective to fill. Likewise, gut microbiota research will be an important tool for filling remaining gaps in anthropological research. © 2016 Wiley Periodicals, Inc.

  12. Incorporating Vibration Test Results for the Advanced Stirling Convertor into the System Dynamic Model

    Science.gov (United States)

    Meer, David W.; Lewandowski, Edward J.

    2010-01-01

    The U.S. Department of Energy (DOE), Lockheed Martin Corporation (LM), and NASA Glenn Research Center (GRC) have been developing the Advanced Stirling Radioisotope Generator (ASRG) for use as a power system for space science missions. As part of the extended operation testing of this power system, the Advanced Stirling Convertors (ASC) at NASA GRC undergo a vibration test sequence intended to simulate the vibration history that an ASC would experience when used in an ASRG for a space mission. During these tests, a data system collects several performance-related parameters from the convertor under test for health monitoring and analysis. Recently, an additional sensor recorded the slip table position during vibration testing to qualification level. The System Dynamic Model (SDM) integrates Stirling cycle thermodynamics, heat flow, mechanical mass, spring, damper systems, and electrical characteristics of the linear alternator and controller. This Paper presents a comparison of the performance of the ASC when exposed to vibration to that predicted by the SDM when exposed to the same vibration.

  13. Computational cardiology: the bidomain based modified Hill model incorporating viscous effects for cardiac defibrillation

    Science.gov (United States)

    Cansız, Barış; Dal, Hüsnü; Kaliske, Michael

    2017-10-01

    Working mechanisms of the cardiac defibrillation are still in debate due to the limited experimental facilities and one-third of patients even do not respond to cardiac resynchronization therapy. With an aim to develop a milestone towards reaching the unrevealed mechanisms of the defibrillation phenomenon, we propose a bidomain based finite element formulation of cardiac electromechanics by taking into account the viscous effects that are disregarded by many researchers. To do so, the material is deemed as an electro-visco-active material and described by the modified Hill model (Cansız et al. in Comput Methods Appl Mech Eng 315:434-466, 2017). On the numerical side, we utilize a staggered solution method, where the elliptic and parabolic part of the bidomain equations and the mechanical field are solved sequentially. The comparative simulations designate that the viscoelastic and elastic formulations lead to remarkably different outcomes upon an externally applied electric field to the myocardial tissue. Besides, the achieved framework requires significantly less computational time and memory compared to monolithic schemes without loss of stability for the presented examples.

  14. An innovative land use regression model incorporating meteorology for exposure analysis.

    Science.gov (United States)

    Su, Jason G; Brauer, Michael; Ainslie, Bruce; Steyn, Douw; Larson, Timothy; Buzzelli, Michael

    2008-02-15

    The advent of spatial analysis and geographic information systems (GIS) has led to studies of chronic exposure and health effects based on the rationale that intra-urban variations in ambient air pollution concentrations are as great as inter-urban differences. Such studies typically rely on local spatial covariates (e.g., traffic, land use type) derived from circular areas (buffers) to predict concentrations/exposures at receptor sites, as a means of averaging the annual net effect of meteorological influences (i.e., wind speed, wind direction and insolation). This is the approach taken in the now popular land use regression (LUR) method. However spatial studies of chronic exposures and temporal studies of acute exposures have not been adequately integrated. This paper presents an innovative LUR method implemented in a GIS environment that reflects both temporal and spatial variability and considers the role of meteorology. The new source area LUR integrates wind speed, wind direction and cloud cover/insolation to estimate hourly nitric oxide (NO) and nitrogen dioxide (NO(2)) concentrations from land use types (i.e., road network, commercial land use) and these concentrations are then used as covariates to regress against NO and NO(2) measurements at various receptor sites across the Vancouver region and compared directly with estimates from a regular LUR. The results show that, when variability in seasonal concentration measurements is present, the source area LUR or SA-LUR model is a better option for concentration estimation.

  15. Searching for the true diet of marine predators: incorporating Bayesian priors into stable isotope mixing models.

    Directory of Open Access Journals (Sweden)

    André Chiaradia

    Full Text Available Reconstructing the diet of top marine predators is of great significance in several key areas of applied ecology, requiring accurate estimation of their true diet. However, from conventional stomach content analysis to recent stable isotope and DNA analyses, no one method is bias or error free. Here, we evaluated the accuracy of recent methods to estimate the actual proportion of a controlled diet fed to a top-predator seabird, the Little penguin (Eudyptula minor. We combined published DNA data of penguins scats with blood plasma δ(15N and δ(13C values to reconstruct the diet of individual penguins fed experimentally. Mismatch between controlled (true ingested diet and dietary estimates obtained through the separately use of stable isotope and DNA data suggested some degree of differences in prey assimilation (stable isotope and digestion rates (DNA analysis. In contrast, combined posterior isotope mixing model with DNA Bayesian priors provided the closest match to the true diet. We provided the first evidence suggesting that the combined use of these complementary techniques may provide better estimates of the actual diet of top marine predators- a powerful tool in applied ecology in the search for the true consumed diet.

  16. Selecting Metrics for Sustainable Bioenergy Feedstocks

    Energy Technology Data Exchange (ETDEWEB)

    Dale, Virginia H [ORNL; Kline, Keith L [ORNL; Mulholland, Patrick J [ORNL; Downing, Mark [ORNL; Graham, Robin Lambert [ORNL; Wright, Lynn L [ORNL

    2009-01-01

    Key decisions about land-use practices and dynamics in biofuel systems affect the long-term sustainability of biofuels. Choices about what crops are grown and how are they planted, fertilized, and harvested determine the effects of biofuels on native plant diversity, competition with food crops, and water and air quality. Those decisions also affect economic viability since the distance that biofuels must be transported has a large effect on the market cost of biofuels. The components of a landscape approach include environmental and socioeconomic conditions and the bioenergy features [type of fuel, plants species, management practices (e.g., fertilizer and pesticide applications), type and location of production facilities] and ecological and biogeochemical feedbacks. Significantly, while water (availability and quality) emerges as one of the most limiting factors to sustainability of bioenergy feedstocks, the linkage between water and bioenergy choices for land use and management on medium and large scales is poorly quantified. Metrics that quantify environmental and socioeconomic changes in land use and landscape dynamics provide a way to measure and communicate the influence of alternative bioenergy choices on water quality and other components of the environment. Cultivation of switchgrass could have both positive and negative environmental effects, depending on where it is planted and what vegetation it replaces. Among the most important environmental effects are changes in the flow regimes of streams (peak storm flows, base flows during the growing season) and changes in stream water quality (sediment, nutrients, and pesticides). Unfortunately, there have been few controlled studies that provide sufficient data to evaluate the hydrological and water quality impacts of conversion to switchgrass. In particular, there is a need for experimental studies that use the small watershed approach to evaluate the effects of growing a perennial plant as a biomass crop

  17. Sophorolipid production from lignocellulosic biomass feedstocks

    Science.gov (United States)

    Samad, Abdul

    The present study investigated the feasibility of production of sophorolipids (SLs) using yeast Candida bombicola grown on hydrolysates derived lignocellulosic feedstock either with or without supplementing oil as extra carbon source. Several researchers have reported using pure sugars and various oil sources for producing SLs which makes them expensive for scale-up and commercial production. In order to make the production process truly sustainable and renewable, we used feedstocks such as sweet sorghum bagasse, corn fiber and corn stover. Without oil supplementation, the cell densities at the end of day-8 was recorded as 9.2, 9.8 and 10.8 g/L for hydrolysate derived from sorghum bagasse, corn fiber, and corn fiber with the addition of yeast extract (YE) during fermentation, respectively. At the end of fermentation, the SL concentration was 3.6 g/L for bagasse and 1.0 g/L for corn fiber hydrolysate. Among the three major sugars utilized by C. bombicola in the bagasse cultures, glucose was consumed at a rate of 9.1 g/L-day; xylose at 1.8 g/L-day; and arabinose at 0.98 g/L-day. With the addition of soybean oil at 100 g/L, cultures with bagasse hydrolysates, corn fiber hydrolysates and standard medium had a cell content of 7.7 g/L; 7.9 g/L; and 8.9 g/L, respectively after 10 days. The yield of SLs from bagasse hydrolysate was 84.6 g/L and corn fiber hydrolysate was15.6 g/L. In the same order, the residual oil in cultures with these two hydrolysates was 52.3 g/L and 41.0 g/L. For this set of experiment; in the cultures with bagasse hydrolysate; utilization rates for glucose, xylose and arabinose was recorded as 9.5, 1.04 and 0.08 g/L-day respectively. Surprisingly, C. bombicola consumed all monomeric sugars and non-sugar compounds in the hydrolysates and cultures with bagasse hydrolysates had higher yield of SLs than those from a standard medium which contained pure glucose at the same concentration. Based on the SL concentrations and considering all sugars consumed

  18. Economic feasibility of producing sweet sorghum as an ethanol feedstock in the southeastern United States

    International Nuclear Information System (INIS)

    Linton, Joseph A.; Miller, J. Corey; Little, Randall D.; Petrolia, Daniel R.; Coble, Keith H.

    2011-01-01

    This study examines the feasibility of producing sweet sorghum (Sorghum bicolor (L.) Moench) as an ethanol feedstock in the southeastern United States through representative counties in Mississippi. We construct enterprise budgets along with estimates of transportation costs to estimate sweet sorghum producers' breakeven costs for producing and delivering sweet sorghum biomass. This breakeven cost for the sweet sorghum producer is used to estimate breakeven costs for the ethanol producer based on wholesale ethanol price, production costs, and transportation and marketing costs. Stochastic models are developed to estimate profits for sweet sorghum and competing crops in two representative counties in Mississippi, with sweet sorghum consistently yielding losses in both counties. -- Highlights: → We examine the economic feasibility of sweet sorghum as an ethanol feedstock. → We construct enterprise budgets along with estimates of transportation costs. → We estimate breakeven costs for producing and delivering sweet sorghum biomass. → Stochastic models determine profits for sweet sorghum in two Mississippi counties.

  19. Influence of feedstock type on heavy coker gas oil quality; A influencia do tipo de carga na qualidade do gasoleo pesado de coque

    Energy Technology Data Exchange (ETDEWEB)

    Costa, Claudine T.A.S.; Barros, Francisco C.C. [PETROBRAS S.A., Rio de Janeiro, RJ (Brazil). Centro de Pesquisas (CENPES)

    2004-07-01

    Over the past few years, the great challenge to the Oil Industry has been the processing of increasingly heavier feedstock seeking to meet the growing demand for medium distillates and, at the same time, the reduction of the production of fuel oils. In this scenario, the Delayed Coking Unit (DCU) appears to be an attractive technology for the processing of heavy and ultra heavy crudes. The addition of Asphaltene Residue produced by the Solvent Deasphalting Unit (SDA) to the Vacuum Residue, traditional feedstock of these units, has been a new tendency in the composition of the feedstock, with the intention of converting the residual fractions into value added liquid oil products. Results obtained in pilot plants show that asphaltene residue alters the yield and the quality of the products of the DCU, especially those of Heavy Coker Gas Oil (HKGO) that is incorporated in the feedstock of the Fluid Catalytic Cracking Unit (FCCU). The alteration in the quality of the HKGO negatively impacts on the conservation of the FCCU. The insertion of DCU in refineries that possess SDA in their refining systems has shown itself to be fundamental for the reduction of the production of fuel oils. However, to define the quantity and quality of asphaltene residue to be incorporated in the feedstock of the UCR, the best operating conditions and the necessary project adaptations to this unit are fundamental and they should be analyzed with the objective of maximizing the profitability of the refineries. (author)

  20. Development of Advanced Continuum Models that Incorporate Nanomechanical Deformation into Engineering Analysis.

    Energy Technology Data Exchange (ETDEWEB)

    Zimmerman, Jonathan A.; Jones, Reese E.; Templeton, Jeremy Alan; McDowell, David L.; Mayeur, Jason R.; Tucker, Garritt J.; Bammann, Douglas J.; Gao, Huajian

    2008-09-01

    Materials with characteristic structures at nanoscale sizes exhibit significantly different mechani-cal responses from those predicted by conventional, macroscopic continuum theory. For example,nanocrystalline metals display an inverse Hall-Petch effect whereby the strength of the materialdecreases with decreasing grain size. The origin of this effect is believed to be a change in defor-mation mechanisms from dislocation motion across grains and pileup at grain boundaries at mi-croscopic grain sizes to rotation of grains and deformation within grain boundary interface regionsfor nanostructured materials. These rotational defects are represented by the mathematical conceptof disclinations. The ability to capture these effects within continuum theory, thereby connectingnanoscale materials phenomena and macroscale behavior, has eluded the research community.The goal of our project was to develop a consistent theory to model both the evolution ofdisclinations and their kinetics. Additionally, we sought to develop approaches to extract contin-uum mechanical information from nanoscale structure to verify any developed continuum theorythat includes dislocation and disclination behavior. These approaches yield engineering-scale ex-pressions to quantify elastic and inelastic deformation in all varieties of materials, even those thatpossess highly directional bonding within their molecular structures such as liquid crystals, cova-lent ceramics, polymers and biological materials. This level of accuracy is critical for engineeringdesign and thermo-mechanical analysis is performed in micro- and nanosystems. The researchproposed here innovates on how these nanoscale deformation mechanisms should be incorporatedinto a continuum mechanical formulation, and provides the foundation upon which to develop ameans for predicting the performance of advanced engineering materials.4 AcknowledgmentThe authors acknowledge helpful discussions with Farid F. Abraham, Youping Chen, Terry J

  1. A Markerless 3D Computerized Motion Capture System Incorporating a Skeleton Model for Monkeys.

    Science.gov (United States)

    Nakamura, Tomoya; Matsumoto, Jumpei; Nishimaru, Hiroshi; Bretas, Rafael Vieira; Takamura, Yusaku; Hori, Etsuro; Ono, Taketoshi; Nishijo, Hisao

    2016-01-01

    In this study, we propose a novel markerless motion capture system (MCS) for monkeys, in which 3D surface images of monkeys were reconstructed by integrating data from four depth cameras, and a skeleton model of the monkey was fitted onto 3D images of monkeys in each frame of the video. To validate the MCS, first, estimated 3D positions of body parts were compared between the 3D MCS-assisted estimation and manual estimation based on visual inspection when a monkey performed a shuttling behavior in which it had to avoid obstacles in various positions. The mean estimation error of the positions of body parts (3-14 cm) and of head rotation (35-43°) between the 3D MCS-assisted and manual estimation were comparable to the errors between two different experimenters performing manual estimation. Furthermore, the MCS could identify specific monkey actions, and there was no false positive nor false negative detection of actions compared with those in manual estimation. Second, to check the reproducibility of MCS-assisted estimation, the same analyses of the above experiments were repeated by a different user. The estimation errors of positions of most body parts between the two experimenters were significantly smaller in the MCS-assisted estimation than in the manual estimation. Third, effects of methamphetamine (MAP) administration on the spontaneous behaviors of four monkeys were analyzed using the MCS. MAP significantly increased head movements, tended to decrease locomotion speed, and had no significant effect on total path length. The results were comparable to previous human clinical data. Furthermore, estimated data following MAP injection (total path length, walking speed, and speed of head rotation) correlated significantly between the two experimenters in the MCS-assisted estimation (r = 0.863 to 0.999). The results suggest that the presented MCS in monkeys is useful in investigating neural mechanisms underlying various psychiatric disorders and developing

  2. Image quality analysis of high-density diffuse optical tomography incorporating a subject-specific head model

    Directory of Open Access Journals (Sweden)

    Yuxuan eZhan

    2012-05-01

    Full Text Available High-density diffuse optical tomography (HD-DOT methods have shown significant improvement in localization accuracy and image resolution compared to traditional topographic near infrared spectroscopy (NIRS of the human brain. In this work we provide a comprehensive evaluation of image quality in visual cortex mapping via a simulation study with the use of an anatomical head model derived from MRI data of a human subject. A model of individual head anatomy provides the surface shape and internal structure that allow for the construction of a more realistic physical model for the forward problem, as well as the use of a structural constraint in the inverse problem. The HD-DOT model utilized here incorporates multiple source-detector separations with continuous-wave data with added noise based on experimental results. To evaluate image quality we quantify the localization error and localized volume at half maximum (LVHM throughout a region of interest (ROI within the visual cortex and systematically analyze the use of whole brain tissue spatial constraint within image reconstruction. Our results demonstrate that an image quality with less than 10 mm in localization error and 1000 m3 in LVHM can be obtained up to 13 mm below the scalp surface with a typical unconstrained reconstruction and up to 18 mm deep when a spatial constraint based on the brain tissue is utilized.

  3. From Field Data to Fracture Network Modeling: An Example Incorporating Spatial Structure

    Science.gov (United States)

    Long, Jane C. S.; Billaux, Daniel M.

    1987-07-01

    This paper describes a technique for processing field data for a fracture network model which accounts for the observed spatial variability. This has been done by generating a network subregion by subregion where the properties of each subregion are predicted through geostatistics. Once the geometry of a particular realization is specified, flow through the network is studied. We develop the method for a two-dimensional analysis based on data from Fanay-Augeres, a uranium mine in France. We plan to extend the analysis to three dimensions and compare the results with in situ test results. In particular, we have focused on the data collected in a long section of a drift where fractures have been mapped and steady state permeability tests have been performed in 10 boreholes. In order to generate fractures in a statistically heterogeneous region we first divided the region into statistically homogeneous subregions. In each subregion and for each fracture set we must specify the areal fracture density and the orientation, length, and aperture distributions. We divided the fractures into five sets based on tectonic history and observed that for each set, fractures spaced close together tended to have similar orientations. This was built into the simulation. An estimate of the aperture distribution for each set was made by assuming that the hydraulic apertures of the fractures intersecting a well test zone were proportional to the fracture opening observed in the core. Data input to the geostatistical analysis for each set consisted of 16 values of mean length and density of fractures in each 5 m by 2 m section of the drift wall. The results of the simulation are tables of values for mean length and fracture density for each of the five sets. The value of density simulated for each subregion was used directly to determine the number of fractures to be generated of that set in the subregion. The value of mean length was used as the mean of the length distribution in the

  4. A bi-level integrated generation-transmission planning model incorporating the impacts of demand response by operation simulation

    International Nuclear Information System (INIS)

    Zhang, Ning; Hu, Zhaoguang; Springer, Cecilia; Li, Yanning; Shen, Bo

    2016-01-01

    Highlights: • We put forward a novel bi-level integrated power system planning model. • Generation expansion planning and transmission expansion planning are combined. • The effects of two sorts of demand response in reducing peak load are considered. • Operation simulation is conducted to reflect the actual effects of demand response. • The interactions between the two levels can guarantee a reasonably optimal result. - Abstract: If all the resources in power supply side, transmission part, and power demand side are considered together, the optimal expansion scheme from the perspective of the whole system can be achieved. In this paper, generation expansion planning and transmission expansion planning are combined into one model. Moreover, the effects of demand response in reducing peak load are taken into account in the planning model, which can cut back the generation expansion capacity and transmission expansion capacity. Existing approaches to considering demand response for planning tend to overestimate the impacts of demand response on peak load reduction. These approaches usually focus on power reduction at the moment of peak load without considering the situations in which load demand at another moment may unexpectedly become the new peak load due to demand response. These situations are analyzed in this paper. Accordingly, a novel approach to incorporating demand response in a planning model is proposed. A modified unit commitment model with demand response is utilized. The planning model is thereby a bi-level model with interactions between generation-transmission expansion planning and operation simulation to reflect the actual effects of demand response and find the reasonably optimal planning result.

  5. Towards a Predictive Thermodynamic Model of Oxidation States of Uranium Incorporated in Fe (hydr) oxides

    Energy Technology Data Exchange (ETDEWEB)

    Bagus, Paul S. [Univ. of North Texas, Denton, TX (United States)

    2013-01-01

    -Level Excited States: Consequences For X-Ray Absorption Spectroscopy”, J. Elec. Spectros. and Related Phenom., 200, 174 (2015) describes our first application of these methods. As well as applications to problems and materials of direct interest for our PNNL colleagues, we have pursued applications of fundamental theoretical significance for the analysis and interpretation of XPS and XAS spectra. These studies are important for the development of the fields of core-level spectroscopies as well as to advance our capabilities for applications of interest to our PNNL colleagues. An excellent example is our study of the surface core-level shifts, SCLS, for the surface and bulk atoms of an oxide that provides a new approach to understanding how the surface electronic of oxides differs from that in the bulk of the material. This work has the potential to lead to a new key to understanding the reactivity of oxide surfaces. Our theoretical studies use cluster models with finite numbers of atoms to describe the properties of condensed phases and crystals. This approach has allowed us to focus on the local atomistic, chemical interactions. For these clusters, we obtain orbitals and spinors through the solution of the Hartree-Fock, HF, and the fully relativistic Dirac HF equations. These orbitals are used to form configuration mixing wavefunctions which treat the many-body effects responsible for the open shell angular momentum coupling and for the satellites of the core-level spectra. Our efforts have been in two complementary directions. As well as the applications described above, we have placed major emphasis on the enhancement and extension of our theoretical and computational capabilities so that we can treat complex systems with a greater range of many-body effects. Noteworthy accomplishments in terms of method development and enhancement have included: (1) An improvement in our treatment of the large matrices that must be handled when many-body effects are treated. (2

  6. An in silico model of the ubiquitin-proteasome system that incorporates normal homeostasis and age-related decline

    Directory of Open Access Journals (Sweden)

    Proctor Carole J

    2007-03-01

    Full Text Available Abstract Background The ubiquitin-proteasome system is responsible for homeostatic degradation of intact protein substrates as well as the elimination of damaged or misfolded proteins that might otherwise aggregate. During ageing there is a decline in proteasome activity and an increase in aggregated proteins. Many neurodegenerative diseases are characterised by the presence of distinctive ubiquitin-positive inclusion bodies in affected regions of the brain. These inclusions consist of insoluble, unfolded, ubiquitinated polypeptides that fail to be targeted and degraded by the proteasome. We are using a systems biology approach to try and determine the primary event in the decline in proteolytic capacity with age and whether there is in fact a vicious cycle of inhibition, with accumulating aggregates further inhibiting proteolysis, prompting accumulation of aggregates and so on. A stochastic model of the ubiquitin-proteasome system has been developed using the Systems Biology Mark-up Language (SBML. Simulations are carried out on the BASIS (Biology of Ageing e-Science Integration and Simulation system and the model output is compared to experimental data wherein levels of ubiquitin and ubiquitinated substrates are monitored in cultured cells under various conditions. The model can be used to predict the effects of different experimental procedures such as inhibition of the proteasome or shutting down the enzyme cascade responsible for ubiquitin conjugation. Results The model output shows good agreement with experimental data under a number of different conditions. However, our model predicts that monomeric ubiquitin pools are always depleted under conditions of proteasome inhibition, whereas experimental data show that monomeric pools were depleted in IMR-90 cells but not in ts20 cells, suggesting that cell lines vary in their ability to replenish ubiquitin pools and there is the need to incorporate ubiquitin turnover into the model. Sensitivity

  7. Genetic Modification of Short Rotation Poplar Biomass Feedstock for Efficient Conversion to Ethanol

    Energy Technology Data Exchange (ETDEWEB)

    Dinus, R.J.

    2000-08-30

    The Bioenergy Feedstock Development Program, Environmental Sciences Division, Oak Ridge National Laboratory is developing poplars (Populus species and hybrids) as sources of renewable energy, i.e., ethanol. Notable increases in adaptability, volume productivity, and pest/stress resistance have been achieved via classical selection and breeding and intensified cultural practices. Significant advances have also been made in the efficiencies of harvesting and handling systems. Given these and anticipated accomplishments, program leaders are considering shifting some attention to genetically modifying feedstock physical and chemical properties, so as to improve the efficiency with which feedstocks can be converted to ethanol. This report provides an in-depth review and synthesis of opportunities for and feasibilities of genetically modifying feedstock qualities via classical selection and breeding, marker-aided selection and breeding, and genetic transformation. Information was collected by analysis of the literature, with emphasis on that published since 1995, and interviews with prominent scientists, breeders, and growers. Poplar research is well advanced, and literature is abundant. The report therefore primarily reflects advances in poplars, but data from other species, particularly other shortrotation hardwoods, are incorporated to fill gaps. An executive summary and recommendations for research, development, and technology transfer are provided immediately after the table of contents. The first major section of the report describes processes most likely to be used for conversion of poplar biomass to ethanol, the various physical and chemical properties of poplar feedstocks, and how such properties are expected to affect process efficiency. The need is stressed for improved understanding of the impact of change on both overall process and individual process step efficiencies. The second part documents advances in trait measurement instrumentation and methodology

  8. Improvement of hydrogen solubility and entrainment in hydrocracker feedstocks. Final technical report

    Energy Technology Data Exchange (ETDEWEB)

    Kabadi, V.N.

    1997-02-01

    The project consisted of two tasks: (1) development of a thermodynamic model for hydrogen solubility in hydrocarbons and extension of this model to predict solubility of hydrogen in hydrocracker feedstocks at conditions similar to those of hydrocracking operations, and (2) design and construction of a gas solubility apparatus to measure solubility of hydrogen in hydrocarbons and in hydrocracker feedstocks. The theoretical work proposed was fully accomplished by developing a sophisticated model for hydrogen solubility in hydrocarbons and in hydrocracker feedstocks at advanced temperatures and pressures. The proposed experimental work ran into a number of obstacles, especially to get the original and newly designed on-line sampling technique to function properly. A number of calibrations and tests for reproducibility were necessary to assure the accuracy of measured data. Although a very well designed gas solubility apparatus was built, not much time was left to generate significant hydrogen solubility data. The plans are to use the apparatus in future to measure hydrogen solubility data in liquid fuels to facilitate more efficient design of fuel conversion systems.

  9. Modelling sediment dynamics due to hillslope-river interactions : incorporating fluvial behaviour in landscape evolution model LAPSUS

    NARCIS (Netherlands)

    Baartman, Jantiene E. M.; van Gorp, Wouter; Temme, Arnaud J. A. M.; Schoorl, Jeroen M.

    Landscape evolution models (LEMs) simulate the three-dimensional development of landscapes over time. Different LEMs have different foci, e.g. erosional behaviour, river dynamics, the fluvial domain, hillslopes or a combination. LEM LAPSUS is a relatively simple cellular model operating on

  10. An improved analytical model of 4H-SiC MESFET incorporating bulk and interface trapping effects

    Science.gov (United States)

    Hema Lata Rao, M.; Narasimha Murty, N. V. L.

    2015-01-01

    An improved analytical model for the current—voltage (I-V) characteristics of the 4H-SiC metal semiconductor field effect transistor (MESFET) on a high purity semi-insulating (HPSI) substrate with trapping and thermal effects is presented. The 4H-SiC MESFET structure includes a stack of HPSI substrates and a uniformly doped channel layer. The trapping effects include both the effect of multiple deep-level traps in the substrate and surface traps between the gate to source/drain. The self-heating effects are also incorporated to obtain the accurate and realistic nature of the analytical model. The importance of the proposed model is emphasised through the inclusion of the recent and exact nature of the traps in the 4H-SiC HPSI substrate responsible for substrate compensation. The analytical model is used to exhibit DC I-V characteristics of the device with and without trapping and thermal effects. From the results, the current degradation is observed due to the surface and substrate trapping effects and the negative conductance introduced by the self-heating effect at a high drain voltage. The calculated results are compared with reported experimental and two-dimensional simulations (Silvaco®-TCAD). The proposed model also illustrates the effectiveness of the gate—source distance scaling effect compared to the gate—drain scaling effect in optimizing 4H-SiC MESFET performance. Results demonstrate that the proposed I-V model of 4H-SiC MESFET is suitable for realizing SiC based monolithic circuits (MMICs) on HPSI substrates.

  11. An improved analytical model of 4H-SiC MESFET incorporating bulk and interface trapping effects

    International Nuclear Information System (INIS)

    Rao, M. Hema Lata; Murty, N. V. L. Narasimha

    2015-01-01

    An improved analytical model for the current—voltage (I–V) characteristics of the 4H-SiC metal semiconductor field effect transistor (MESFET) on a high purity semi-insulating (HPSI) substrate with trapping and thermal effects is presented. The 4H-SiC MESFET structure includes a stack of HPSI substrates and a uniformly doped channel layer. The trapping effects include both the effect of multiple deep-level traps in the substrate and surface traps between the gate to source/drain. The self-heating effects are also incorporated to obtain the accurate and realistic nature of the analytical model. The importance of the proposed model is emphasised through the inclusion of the recent and exact nature of the traps in the 4H-SiC HPSI substrate responsible for substrate compensation. The analytical model is used to exhibit DC I–V characteristics of the device with and without trapping and thermal effects. From the results, the current degradation is observed due to the surface and substrate trapping effects and the negative conductance introduced by the self-heating effect at a high drain voltage. The calculated results are compared with reported experimental and two-dimensional simulations (Silvaco®-TCAD). The proposed model also illustrates the effectiveness of the gate—source distance scaling effect compared to the gate—drain scaling effect in optimizing 4H-SiC MESFET performance. Results demonstrate that the proposed I–V model of 4H-SiC MESFET is suitable for realizing SiC based monolithic circuits (MMICs) on HPSI substrates. (semiconductor devices)

  12. Incorporation of expert variability into breast cancer treatment recommendation in designing clinical protocol guided fuzzy rule system models.

    Science.gov (United States)

    Garibaldi, Jonathan M; Zhou, Shang-Ming; Wang, Xiao-Ying; John, Robert I; Ellis, Ian O

    2012-06-01

    It has been often demonstrated that clinicians exhibit both inter-expert and intra-expert variability when making difficult decisions. In contrast, the vast majority of computerized models that aim to provide automated support for such decisions do not explicitly recognize or replicate this variability. Furthermore, the perfect consistency of computerized models is often presented as a de facto benefit. In this paper, we describe a novel approach to incorporate variability within a fuzzy inference system using non-stationary fuzzy sets in order to replicate human variability. We apply our approach to a decision problem concerning the recommendation of post-operative breast cancer treatment; specifically, whether or not to administer chemotherapy based on assessment of five clinical variables: NPI (the Nottingham Prognostic Index), estrogen receptor status, vascular invasion, age and lymph node status. In doing so, we explore whether such explicit modeling of variability provides any performance advantage over a more conventional fuzzy approach, when tested on a set of 1310 unselected cases collected over a fourteen year period at the Nottingham University Hospitals NHS Trust, UK. The experimental results show that the standard fuzzy inference system (that does not model variability) achieves overall agreement to clinical practice around 84.6% (95% CI: 84.1-84.9%), while the non-stationary fuzzy model can significantly increase performance to around 88.1% (95% CI: 88.0-88.2%), pfuzzy models provide a valuable new approach that may be applied to clinical decision support systems in any application domain. Copyright © 2012 Elsevier Inc. All rights reserved.

  13. Roadmap for Agriculture Biomass Feedstock Supply in the United States

    Energy Technology Data Exchange (ETDEWEB)

    J. Richard Hess; Thomas D. Foust; Reed Hoskinson; David Thompson

    2003-11-01

    The Biomass Research and Development Technical Advisory Committee established a goal that biomass will supply 5% of the nation’s power, 20% of its transportation fuels, and 25% of its chemicals by 2030. These combined goals are approximately equivalent to 30% of the country’s current petroleum consumption. The benefits of a robust biorefinery industry supplying this amount of domestically produced power, fuels, and products are considerable, including decreased demand for imported oil, revenue to the depressed agricultural industry, and revitalized rural economies. A consistent supply of highquality, low-cost feedstock is vital to achieving this goal. This biomass roadmap defines the research and development (R&D) path to supplying the feedstock needs of the biorefinery and to achieving the important national goals set for biomass. To meet these goals, the biorefinery industry must be more sustainable than the systems it will replace. Sustainability hinges on the economic profitability of all participants, on environmental impact of every step in the process, and on social impact of the product and its production. In early 2003, a series of colloquies were held to define and prioritize the R&D needs for supplying feedstock to the biorefinery in a sustainable manner. These colloquies involved participants and stakeholders in the feedstock supply chain, including growers, transporters, equipment manufacturers, and processors as well as environmental groups and others with a vested interest in ensuring the sustainability of the biorefinery. From this series of colloquies, four high-level strategic goals were set for the feedstock area: • Biomass Availability – By 2030, 1 billion dry tons of lignocellulosic feedstock is needed annually to achieve the power, fuel, and chemical production goals set by the Biomass Research and Development Technology Advisory Production Committee • Sustainability – Production and use of the 1 billion dry tons annually must be

  14. Incorporating the subgrid-scale variability of clouds in the autoconversion parameterization in a large-scale model

    Science.gov (United States)

    Weber, Torsten; Quaas, Johannes

    2010-05-01

    Precipitation formation in warm clouds is mainly governed by the autoconversion rate being a high nonlinear process. Large scale models commonly calculate the autoconversion rate using the grid-cell mean of liquid cloud water which introduces a strong low-bias because clouds and therefore liquid cloud water are inhomogeneous distributed. The parameterized autoconversion is thus artificially tuned so that accumulated large-scale precipitation matches the observations. Here, we revise the parameterization for the autoconversion rate to incorporate the subgrid-scale variability of clouds using the horizontal subgrid-scale distribution of liquid cloud water mixing ratio derived from the subgrid-scale variability scheme of water vapor and cloud condensate. This scheme is employed in the ECHAM5 climate model in order to calculate the horizontal cloud fraction by means of a probability density function (PDF) of the total water mixing ratio. The revised parameterization now also ensures the consistency between the calculation of horizontal cloud fraction and the precipitation formation. An introduction of the improved parameterization and first results of the evaluation of the precipitation rate on a global scale will be presented. Specifically, precipitation and vertically integrated liquid cloud water estimated by the model are compared with observational data derived from ground based measurements and satellite instruments.

  15. Aquatic weeds as the next generation feedstock for sustainable bioenergy production.

    Science.gov (United States)

    Kaur, Manpreet; Kumar, Manoj; Sachdeva, Sarita; Puri, S K

    2018-03-01

    Increasing oil prices and depletion of existing fossil fuel reserves, combined with the continuous rise in greenhouse gas emissions, have fostered the need to explore and develop new renewable bioenergy feedstocks that do not require arable land and freshwater resources. In this regard, prolific biomass growth of invasive aquatic weeds in wastewater has gained much attention in recent years in utilizing them as a potential feedstock for bioenergy production. Aquatic weeds have an exceptionally higher reproduction rates and are rich in cellulose and hemicellulose with a very low lignin content that makes them an efficient next generation biofuel crop. Considering their potential as an effective phytoremediators, this review presents a model of integrated aquatic biomass production, phytoremediation and bioenergy generation to reduce the land, fresh water and fertilizer usage for sustainable and economical bioenergy. Copyright © 2017. Published by Elsevier Ltd.

  16. Incorporation of velocity-dependent restitution coefficient and particle surface friction into kinetic theory for modeling granular flow cooling.

    Science.gov (United States)

    Duan, Yifei; Feng, Zhi-Gang

    2017-12-01

    Kinetic theory (KT) has been successfully used to model rapid granular flows in which particle interactions are frictionless and near elastic. However, it fails when particle interactions become frictional and inelastic. For example, the KT is not able to accurately predict the free cooling process of a vibrated granular medium that consists of inelastic frictional particles under microgravity. The main reason that the classical KT fails to model these flows is due to its inability to account for the particle surface friction and its inelastic behavior, which are the two most important factors that need be considered in modeling collisional granular flows. In this study, we have modified the KT model that is able to incorporate these two factors. The inelasticity of a particle is considered by establishing a velocity-dependent expression for the restitution coefficient based on many experimental studies found in the literature, and the particle friction effect is included by using a tangential restitution coefficient that is related to the particle friction coefficient. Theoretical predictions of the free cooling process by the classical KT and the improved KT are compared with the experimental results from a study conducted on an airplane undergoing parabolic flights without the influence of gravity [Y. Grasselli, G. Bossis, and G. Goutallier, Europhys. Lett. 86, 60007 (2009)10.1209/0295-5075/86/60007]. Our results show that both the velocity-dependent restitution coefficient and the particle surface friction are important in predicting the free cooling process of granular flows; the modified KT model that integrates these two factors is able to improve the simulation results and leads to better agreement with the experimental results.

  17. Incorporation of velocity-dependent restitution coefficient and particle surface friction into kinetic theory for modeling granular flow cooling

    Science.gov (United States)

    Duan, Yifei; Feng, Zhi-Gang

    2017-12-01

    Kinetic theory (KT) has been successfully used to model rapid granular flows in which particle interactions are frictionless and near elastic. However, it fails when particle interactions become frictional and inelastic. For example, the KT is not able to accurately predict the free cooling process of a vibrated granular medium that consists of inelastic frictional particles under microgravity. The main reason that the classical KT fails to model these flows is due to its inability to account for the particle surface friction and its inelastic behavior, which are the two most important factors that need be considered in modeling collisional granular flows. In this study, we have modified the KT model that is able to incorporate these two factors. The inelasticity of a particle is considered by establishing a velocity-dependent expression for the restitution coefficient based on many experimental studies found in the literature, and the particle friction effect is included by using a tangential restitution coefficient that is related to the particle friction coefficient. Theoretical predictions of the free cooling process by the classical KT and the improved KT are compared with the experimental results from a study conducted on an airplane undergoing parabolic flights without the influence of gravity [Y. Grasselli, G. Bossis, and G. Goutallier, Europhys. Lett. 86, 60007 (2009), 10.1209/0295-5075/86/60007]. Our results show that both the velocity-dependent restitution coefficient and the particle surface friction are important in predicting the free cooling process of granular flows; the modified KT model that integrates these two factors is able to improve the simulation results and leads to better agreement with the experimental results.

  18. Incorporating Field Studies into Species Distribution and Climate Change Modelling: A Case Study of the Koomal Trichosurus vulpecula hypoleucus (Phalangeridae.

    Directory of Open Access Journals (Sweden)

    Shaun W Molloy

    Full Text Available Species distribution models (SDMs are an effective way of predicting the potential distribution of species and their response to environmental change. Most SDMs apply presence data to a relatively generic set of predictive variables such as climate. However, this weakens the modelling process by overlooking the responses to more cryptic predictive variables. In this paper we demonstrate a means by which data gathered from an intensive animal trapping study can be used to enhance SDMs by combining field data with bioclimatic modelling techniques to determine the future potential distribution for the koomal (Trichosurus vulpecula hypoleucus. The koomal is a geographically isolated subspecies of the common brushtail possum, endemic to south-western Australia. Since European settlement this taxon has undergone a significant reduction in distribution due to its vulnerability to habitat fragmentation, introduced predators and tree/shrub dieback caused by a virulent group of plant pathogens of the genus Phytophthora. An intensive field study found: 1 the home range for the koomal rarely exceeded 1 km in in length at its widest point; 2 areas heavily infested with dieback were not occupied; 3 gap crossing between patches (>400 m was common behaviour; 4 koomal presence was linked to the extent of suitable vegetation; and 5 where the needs of koomal were met, populations in fragments were demographically similar to those found in contiguous landscapes. We used this information to resolve a more accurate SDM for the koomal than that created from bioclimatic data alone. Specifically, we refined spatial coverages of remnant vegetation and dieback, to develop a set of variables that we combined with selected bioclimatic variables to construct models. We conclude that the utility value of an SDM can be enhanced and given greater resolution by identifying variables that reflect observed, species-specific responses to landscape parameters and incorporating these

  19. Corn-based feedstock for biofuels: Implications for agricultural sustainability

    Science.gov (United States)

    Tan, Z.

    2010-12-01

    Crop residue as a source of feedstock for biofuels production must retain ecosystem services and be sustainable. The challenge is to develop cropping system management strategies that balance the demand for increasing biofuel needs with ecosystem sustainability. This study was designed to evaluate impacts of changes in land use and management caused by corn-based biofuel production (grain, cob, stover) on soil fertility and ecosystem sustainability. Our specific goal was to investigate how the levels of corn residue removal influence current soil carbon and nutrient budgets and how these budgets are maintained under proposed production scenarios. Soil organic carbon (SOC), an important carbon component in the life cycle of biofuel production, is a sensitive indicator of cropping system sustainability. We used a soil carbon and nutrient balance approach developed from published field observations and a validated mechanistic model to analyze historical corn grain yields and fertilizer usage associated with various management practices at the county scale across the United States. Our analyses show that ecosystem carbon flux demonstrates significant spatial variability, relying heavily on the total biomass production level and residue harvest intensity; SOC budgets depend mainly on the proportion of residue removal, tillage type, and previous SOC stock level. Our results also indicate that corn cob removal for biofuel has little effect on soil carbon and nutrient balances under conventional management practices, while necessary irrigation can contribute greatly to corn-based biofuel production and ecosystem sustainability in the western side of the Great Plains and the eastern foothills of the Rocky Mountains.

  20. Electrospun nanofiber sheets incorporating methylcobalamin promote nerve regeneration and functional recovery in a rat sciatic nerve crush injury model.

    Science.gov (United States)

    Suzuki, Koji; Tanaka, Hiroyuki; Ebara, Mitsuhiro; Uto, Koichiro; Matsuoka, Hozo; Nishimoto, Shunsuke; Okada, Kiyoshi; Murase, Tsuyoshi; Yoshikawa, Hideki

    2017-04-15

    Peripheral nerve injury is one of common traumas. Although injured peripheral nerves have the capacity to regenerate, axon regeneration proceeds slowly and functional outcomes are often poor. Pharmacological enhancement of regeneration can play an important role in increasing functional recovery. In this study, we developed a novel electrospun nanofiber sheet incorporating methylcobalamin (MeCbl), one of the active forms of vitamin B12 homologues, to deliver it enough locally to the peripheral nerve injury site. We evaluated whether local administration of MeCbl at the nerve injury site was effective in promoting nerve regeneration. Electrospun nanofiber sheets gradually released MeCbl for at least 8weeks when tested in vitro. There was no adverse effect of nanofiber sheets on function in vivo of the peripheral nervous system. Local implantation of nanofiber sheets incorporating MeCbl contributed to the recovery of the motor and sensory function, the recovery of nerve conduction velocity, and the promotion of myelination after sciatic nerve injury, without affecting plasma concentration of MeCbl. Methylcobalamin (MeCbl) is a vitamin B12 analog and we previously reported its effectiveness in axonal outgrowth of neurons and differentiation of Schwann cells both in vitro and in vivo. Here we estimated the effect of local administered MeCbl with an electrospun nanofiber sheet on peripheral nerve injury. Local administration of MeCbl promoted functional recovery in a rat sciatic nerve crush injury model. These sheets are useful for nerve injury in continuity differently from artificial nerve conduits, which are useful only for nerve defects. We believe that the findings of this study are relevant to the scope of your journal and will be of interest to its readership. Copyright © 2017 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.

  1. Comparison in the calculation of committed effective dose using the ICRP 30 and ICRP 60 models for a repeated incorporation by inhalation of I-125

    International Nuclear Information System (INIS)

    Carreno P, A.L.; Cortes C, A.; Alonso V, G.; Serrano P, F.

    2005-01-01

    Presently work, a comparison in the calculation of committed effective dose using the models of the ICRP 30 and those of the ICRP 60 for the analysis of internal dose due to repeated incorporation of I-125 is shown. The estimations of incorporated activity are obtained starting from the proportionate data for an exercise of inter comparison, with which it should be determined the internal dose later on. For to estimate the initial activity incorporated by repeated dose was assumed that this it was given through of multiple individual incorporations which happened in the middle points of the monitoring periods. The results using the models of the ICRP 30 and of the ICRP 60 are compared and the causes of the differences are analyzed. (Author)

  2. A modified Wright-Fisher model that incorporates Ne: A variant of the standard model with increased biological realism and reduced computational complexity.

    Science.gov (United States)

    Zhao, Lei; Gossmann, Toni I; Waxman, David

    2016-03-21

    The Wright-Fisher model is an important model in evolutionary biology and population genetics. It has been applied in numerous analyses of finite populations with discrete generations. It is recognised that real populations can behave, in some key aspects, as though their size that is not the census size, N, but rather a smaller size, namely the effective population size, Ne. However, in the Wright-Fisher model, there is no distinction between the effective and census population sizes. Equivalently, we can say that in this model, Ne coincides with N. The Wright-Fisher model therefore lacks an important aspect of biological realism. Here, we present a method that allows Ne to be directly incorporated into the Wright-Fisher model. The modified model involves matrices whose size is determined by Ne. Thus apart from increased biological realism, the modified model also has reduced computational complexity, particularly so when Ne⪡N. For complex problems, it may be hard or impossible to numerically analyse the most commonly-used approximation of the Wright-Fisher model that incorporates Ne, namely the diffusion approximation. An alternative approach is simulation. However, the simulations need to be sufficiently detailed that they yield an effective size that is different to the census size. Simulations may also be time consuming and have attendant statistical errors. The method presented in this work may then be the only alternative to simulations, when Ne differs from N. We illustrate the straightforward application of the method to some problems involving allele fixation and the determination of the equilibrium site frequency spectrum. We then apply the method to the problem of fixation when three alleles are segregating in a population. This latter problem is significantly more complex than a two allele problem and since the diffusion equation cannot be numerically solved, the only other way Ne can be incorporated into the analysis is by simulation. We have

  3. Spatial Analysis of Biomass Resources within a Socio-Ecologically Heterogeneous Region: Identifying Opportunities for a Mixed Feedstock Stream

    Directory of Open Access Journals (Sweden)

    Kirby Calvert

    2014-02-01

    Full Text Available Local bioenergy will play a crucial role in national and regional sustainable energy strategies. Effective siting and feedstock procurement strategies are critical to the development and implementation of bioenergy systems. This paper aims to improve spatial decision-support in this domain by shifting focus from homogenous (forestry or agricultural regions toward heterogeneous regions—i.e., areas with a presence of both forestry and agricultural activities; in this case, eastern Ontario, Canada. Multiple land-cover and resource map series are integrated in order to produce a spatially distributed GIS-based model of resource availability. These data are soft-linked with spreadsheet-based linear models in order to estimate and compare the quantity and supply-cost of the full range of non-food bioenergy feedstock available to a prospective developer, and to assess the merits of a mixed feedstock stream relative to a homogenous feedstock stream. The method is applied to estimate bioenergy production potentials and biomass supply-cost curves for a number of cities in the study region. Comparisons of biomass catchment areas; supply-cost curves; resource density maps; and resource flow charts demonstrate considerable strategic and operational advantages to locating a facility within the region’s “transition zone” between forestry and agricultural activities. Existing and emerging bioenergy technologies that are feedstock agnostic and therefore capable of accepting a mixed-feedstock stream are reviewed with emphasis on “intermediates” such as wood pellets; biogas; and bio-oils, as well as bio-industrial clusters.

  4. Modified lingguizhugan decoction incorporated with dietary restriction and exercise ameliorates hyperglycemia, hyperlipidemia and hypertension in a rat model of the metabolic syndrome

    OpenAIRE

    Yao, Limei; Wei, Jingjing; Shi, Si; Guo, Kunbin; Wang, Xiangyu; Wang, Qi; Chen, Dingsheng; Li, Weirong

    2017-01-01

    Background Modified Lingguizhugan Decoction (MLD) came from famous Chinese medicine Linggui Zhugan Decoction. The MLD is used for the treatment of metabolic syndrome in the clinical setting. Our study focuses on the comprehensive treatment of MLD incorporated with dietary restriction and exercise in a rat model of the metabolic syndrome (MS). Methods Rats were divided into five groups: control group (Cont), high-fat diet group (HFD), high-fat diet incorporated with dietary restriction group (...

  5. Stochastic modeling of phosphorus transport in the Three Gorges Reservoir by incorporating variability associated with the phosphorus partition coefficient

    Energy Technology Data Exchange (ETDEWEB)

    Huang, Lei; Fang, Hongwei; Xu, Xingya; He, Guojian; Zhang, Xuesong; Reible, Danny

    2017-08-01

    Phosphorus (P) fate and transport plays a crucial role in the ecology of rivers and reservoirs in which eutrophication is limited by P. A key uncertainty in models used to help manage P in such systems is the partitioning of P to suspended and bed sediments. By analyzing data from field and laboratory experiments, we stochastically characterize the variability of the partition coefficient (Kd) and derive spatio-temporal solutions for P transport in the Three Gorges Reservoir (TGR). We formulate a set of stochastic partial different equations (SPDEs) to simulate P transport by randomly sampling Kd from the measured distributions, to obtain statistical descriptions of the P concentration and retention in the TGR. The correspondence between predicted and observed P concentrations and P retention in the TGR combined with the ability to effectively characterize uncertainty suggests that a model that incorporates the observed variability can better describe P dynamics and more effectively serve as a tool for P management in the system. This study highlights the importance of considering parametric uncertainty in estimating uncertainty/variability associated with simulated P transport.

  6. Incorporating adolescent females' perceptions of their partners' attitudes toward condoms into a model of female adolescent condom use.

    Science.gov (United States)

    Hogben, Matthew; Liddon, Nicole; Pierce, Antonya; Sawyer, Mary; Papp, John R; Black, Carolyn M; Koumans, Emilia H

    2006-11-01

    The highest rates of sexually transmitted infections in the U.S. occur among adolescent females. One prevention strategy promoted for sexually active adolescents is condom use: therefore, influences on correct and consistent condom use are worth examining. Because interventions and observational research into predicting and increasing condom use have yielded mixed results, we hypothesized that a theoretically driven model incorporating female adolescents' perceptions about partner sentiments along with their own perceptions, intentions, and behaviours would improve condom use predictions. We also measured condom use errors and consistency for a more precise estimate of effective use than is common in the literature. In three structural equation models tested on a sample of 519 female adolescents, we found that intentions were associated with both correct and consistent condom use; that females' expectancy beliefs about condom use were associated with intentions; and that females' expectancy beliefs about partners' sentiments reduced the impact of their expectancy beliefs about condom use. The implications of these relations upon condom use correctness and consistency are discussed with respect to informing interventions, among other future research.

  7. Fuzzy Case-Based Reasoning in Product Style Acquisition Incorporating Valence-Arousal-Based Emotional Cellular Model

    Directory of Open Access Journals (Sweden)

    Fuqian Shi

    2012-01-01

    Full Text Available Emotional cellular (EC, proposed in our previous works, is a kind of semantic cell that contains kernel and shell and the kernel is formalized by a triple- L = , where P denotes a typical set of positive examples relative to word-L, d is a pseudodistance measure on emotional two-dimensional space: valence-arousal, and δ is a probability density function on positive real number field. The basic idea of EC model is to assume that the neighborhood radius of each semantic concept is uncertain, and this uncertainty will be measured by one-dimensional density function δ. In this paper, product form features were evaluated by using ECs and to establish the product style database, fuzzy case based reasoning (FCBR model under a defined similarity measurement based on fuzzy nearest neighbors (FNN incorporating EC was applied to extract product styles. A mathematical formalized inference system for product style was also proposed, and it also includes uncertainty measurement tool emotional cellular. A case study of style acquisition of mobile phones illustrated the effectiveness of the proposed methodology.

  8. Experimental characterization and computational modeling of unimorph shape memory polymer actuators incorporating transverse curvature in the substrate

    Science.gov (United States)

    Cantrell, Jason T.

    This document outlines in detail the research performed by applying shape memory polymers in a generic unimorph actuator configuration. A set of experiments designed to investigate the influence of transverse curvature, the relative widths of shape memory polymer and composite substrates, and shape memory polymer thickness on actuator recoverability after multiple thermo-mechanical cycles is presented in detail. A theoretical model of the moment required to maintain shape fixity with minimal shape retention loss was developed and experimentally validated for unimorph composite actuators of varying cross-sectional areas. Theoretical models were also developed and evaluated to determine the relationship between the materials neutral axes and thermal stability during a thermo-mechanical cycle. Research was conducted on the incorporation of shape memory polymers on micro air vehicle wings to maximize shape fixity and shape recoverability while minimizing the volume of shape memory polymer on the wing surface. Applications based research also included experimentally evaluating the feasibility of shape memory polymers on deployable satellite antenna ribs both with and without resistance heaters which could be utilized to assist in antenna deployment.

  9. Evaluating the Capacity of Global CO2 Flux and Atmospheric Transport Models to Incorporate New Satellite Observations

    Science.gov (United States)

    Kawa, S. R.; Collatz, G. J.; Erickson, D. J.; Denning, A. S.; Wofsy, S. C.; Andrews, A. E.

    2007-01-01

    As we enter the new era of satellite remote sensing for CO2 and other carbon cyclerelated quantities, advanced modeling and analysis capabilities are required to fully capitalize on the new observations. Model estimates of CO2 surface flux and atmospheric transport are required for initial constraints on inverse analyses, to connect atmospheric observations to the location of surface sources and sinks, and ultimately for future projections of carbon-climate interactions. For application to current, planned, and future remotely sensed CO2 data, it is desirable that these models are accurate and unbiased at time scales from less than daily to multi-annual and at spatial scales from several kilometers or finer to global. Here we focus on simulated CO2 fluxes from terrestrial vegetation and atmospheric transport mutually constrained by analyzed meteorological fields from the Goddard Modeling and Assimilation Office for the period 1998 through 2006. Use of assimilated meteorological data enables direct model comparison to observations across a wide range of scales of variability. The biospheric fluxes are produced by the CASA model at lxi degrees on a monthly mean basis, modulated hourly with analyzed temperature and sunlight. Both physiological and biomass burning fluxes are derived using satellite observations of vegetation, burned area (as in GFED-2), and analyzed meteorology. For the purposes of comparison to CO2 data, fossil fuel and ocean fluxes are also included in the transport simulations. In this presentation we evaluate the model's ability to simulate CO2 flux and mixing ratio variability in comparison to in situ observations at sites in Northern mid latitudes and the continental tropics. The influence of key process representations is inferred. We find that the model can resolve much of the hourly to synoptic variability in the observations, although there are limits imposed by vertical resolution of boundary layer processes. The seasonal cycle and its

  10. Recent Progresses in Incorporating Human Land-Water Management into Global Land Surface Models Toward Their Integration into Earth System Models

    Science.gov (United States)

    Pokhrel, Yadu N.; Hanasaki, Naota; Wada, Yoshihide; Kim, Hyungjun

    2016-01-01

    The global water cycle has been profoundly affected by human land-water management. As the changes in the water cycle on land can affect the functioning of a wide range of biophysical and biogeochemical processes of the Earth system, it is essential to represent human land-water management in Earth system models (ESMs). During the recent past, noteworthy progress has been made in large-scale modeling of human impacts on the water cycle but sufficient advancements have not yet been made in integrating the newly developed schemes into ESMs. This study reviews the progresses made in incorporating human factors in large-scale hydrological models and their integration into ESMs. The study focuses primarily on the recent advancements and existing challenges in incorporating human impacts in global land surface models (LSMs) as a way forward to the development of ESMs with humans as integral components, but a brief review of global hydrological models (GHMs) is also provided. The study begins with the general overview of human impacts on the water cycle. Then, the algorithms currently employed to represent irrigation, reservoir operation, and groundwater pumping are discussed. Next, methodological deficiencies in current modeling approaches and existing challenges are identified. Furthermore, light is shed on the sources of uncertainties associated with model parameterizations, grid resolution, and datasets used for forcing and validation. Finally, representing human land-water management in LSMs is highlighted as an important research direction toward developing integrated models using ESM frameworks for the holistic study of human-water interactions within the Earths system.

  11. Model-Based Evaluation of Higher Doses of Rifampin Using a Semimechanistic Model Incorporating Autoinduction and Saturation of Hepatic Extraction.

    Science.gov (United States)

    Chirehwa, Maxwell T; Rustomjee, Roxana; Mthiyane, Thuli; Onyebujoh, Philip; Smith, Peter; McIlleron, Helen; Denti, Paolo

    2016-01-01

    Rifampin is a key sterilizing drug in the treatment of tuberculosis (TB). It induces its own metabolism, but neither the onset nor the extent of autoinduction has been adequately described. Currently, the World Health Organization recommends a rifampin dose of 8 to 12 mg/kg of body weight, which is believed to be suboptimal, and higher doses may potentially improve treatment outcomes. However, a nonlinear increase in exposure may be observed because of saturation of hepatic extraction and hence this should be taken into consideration when a dose increase is implemented. Intensive pharmacokinetic (PK) data from 61 HIV-TB-coinfected patients in South Africa were collected at four visits, on days 1, 8, 15, and 29, after initiation of treatment. Data were analyzed by population nonlinear mixed-effects modeling. Rifampin PKs were best described by using a transit compartment absorption and a well-stirred liver model with saturation of hepatic extraction, including a first-pass effect. Autoinduction was characterized by using an exponential-maturation model: hepatic clearance almost doubled from the baseline to steady state, with a half-life of around 4.5 days. The model predicts that increases in the dose of rifampin result in more-than-linear drug exposure increases as measured by the 24-h area under the concentration-time curve. Simulations with doses of up to 35 mg/kg produced results closely in line with those of clinical trials. Copyright © 2015, American Society for Microbiology. All Rights Reserved.

  12. Modeling regional cropland GPP by empirically incorporating sun-induced chlorophyll fluorescence into a coupled photosynthesis-fluorescence model

    Science.gov (United States)

    Zhang, Y.; Guanter, L.; Van der Tol, C.; Joiner, J.; Berry, J. A.

    2015-12-01

    Global sun-induced chlorophyll fluorescence (SIF) retrievals are currently available from several satellites. SIF is intrinsically linked to photosynthesis, so the new data sets allow to link remotely-sensed vegetation parameters and the actual photosynthetic activity of plants. In this study, we used space measurements of SIF together with the Soil-Canopy Observation of Photosynthesis and Energy (SCOPE) balance model in order to simulate regional photosynthetic uptake of croplands in the US corn belt. SCOPE couples fluorescence and photosynthesis at leaf and canopy levels. To do this, we first retrieved a key parameter of photosynthesis model, the maximum rate of carboxylation (Vcmax), from field measurements of CO2 and water flux during 2007-2012 at some crop eddy covariance flux sites in the Midwestern US. Then we empirically calibrated Vcmax with apparent fluorescence yield which is SIF divided by PAR. SIF retrievals are from the European GOME-2 instrument onboard the MetOp-A platform. The resulting apparent fluorescence yield shows a stronger relationship with Vcmax during the growing season than widely-used vegetation index, EVI and NDVI. New seasonal and regional Vcmax maps were derived based on the calibration model for the cropland of the corn belt. The uncertainties of Vcmax were also estimated through Gaussian error propagation. With the newly derived Vcmax maps, we modeled regional cropland GPP during the growing season for the Midwestern USA, with meteorological data from MERRA reanalysis data and LAI from MODIS product (MCD15A2). The results show the improvement in the seasonal and spatial patterns of cropland productivity in comparisons with both flux tower and agricultural inventory data.

  13. An integrated stochastic multi-regional long-term energy planning model incorporating autonomous power systems and demand response

    International Nuclear Information System (INIS)

    Koltsaklis, Nikolaos E.; Liu, Pei; Georgiadis, Michael C.

    2015-01-01

    The power sector faces a rapid transformation worldwide from a dominant fossil-fueled towards a low carbon electricity generation mix. Renewable energy technologies (RES) are steadily becoming a greater part of the global energy mix, in particular in regions that have put in place policies and measures to promote their utilization. This paper presents an optimization-based approach to address the generation expansion planning (GEP) problem of a large-scale, central power system in a highly uncertain and volatile electricity industry environment. A multi-regional, multi-period linear mixed-integer linear programming (MILP) model is presented, combining optimization techniques with a Monte Carlo (MCA) method and demand response concepts. The optimization goal concerns the minimization of the total discounted cost by determining optimal power capacity additions per time interval and region, and the power generation mix per technology and time period. The model is evaluated on the Greek power system (GPS), taking also into consideration the scheduled interconnection of the mainland power system with those of selected autonomous islands (Cyclades and Crete), and aims at providing full insight into the composition of the long-term energy roadmap at a national level. - Highlights: • A spatial, multi-period, long-term generation expansion planning model is presented. • A Monte-Carlo method along with a demand response mechanism are incorporated. • Autonomous power systems interconnection is considered. • Electricity and CO 2 emission trade are taken into account. • Lignite, natural gas and wind power comprise the dominant power technologies

  14. A new heat flux model for the Antarctic Peninsula incorporating spatially variable upper crustal radiogenic heat production

    Science.gov (United States)

    Burton-Johnson, A.; Halpin, J.; Whittaker, J. M.; Graham, F. S.; Watson, S. J.

    2017-12-01

    We present recently published findings (Burton-Johnson et al., 2017) on the variability of Antarctic sub-glacial heat flux and the impact from upper crustal geology. Our new method reveals that the upper crust contributes up to 70% of the Antarctic Peninsula's subglacial heat flux, and that heat flux values are more variable at smaller spatial resolutions than geophysical methods can resolve. Results indicate a higher heat flux on the east and south of the Peninsula (mean 81 mWm-2) where silicic rocks predominate, than on the west and north (mean 67 mWm-2) where volcanic arc and quartzose sediments are dominant. Whilst the data supports the contribution of HPE-enriched granitic rocks to high heat flux values, sedimentary rocks can be of comparative importance dependent on their provenance and petrography. Models of subglacial heat flux must utilize a heterogeneous upper crust with variable radioactive heat production if they are to accurately predict basal conditions of the ice sheet. Our new methodology and dataset facilitate improved numerical model simulations of ice sheet dynamics. The most significant challenge faced remains accurate determination of crustal structure, particularly the depths of the HPE-enriched sedimentary basins and the sub-glacial geology away from exposed outcrops. Continuing research (particularly detailed geophysical interpretation) will better constrain these unknowns and the effect of upper crustal geology on the Antarctic ice sheet. Burton-Johnson, A., Halpin, J.A., Whittaker, J.M., Graham, F.S., and Watson, S.J., 2017, A new heat flux model for the Antarctic Peninsula incorporating spatially variable upper crustal radiogenic heat production: Geophysical Research Letters, v. 44, doi: 10.1002/2017GL073596.

  15. Cost Methodology for Biomass Feedstocks: Herbaceous Crops and Agricultural Residues

    Energy Technology Data Exchange (ETDEWEB)

    Turhollow Jr, Anthony F [ORNL; Webb, Erin [ORNL; Sokhansanj, Shahabaddine [ORNL

    2009-12-01

    This report describes a set of procedures and assumptions used to estimate production and logistics costs of bioenergy feedstocks from herbaceous crops and agricultural residues. The engineering-economic analysis discussed here is based on methodologies developed by the American Society of Agricultural and Biological Engineers (ASABE) and the American Agricultural Economics Association (AAEA). An engineering-economic analysis approach was chosen due to lack of historical cost data for bioenergy feedstocks. Instead, costs are calculated using assumptions for equipment performance, input prices, and yield data derived from equipment manufacturers, research literature, and/or standards. Cost estimates account for fixed and variable costs. Several examples of this costing methodology used to estimate feedstock logistics costs are included at the end of this report.

  16. Deletion of the pflA gene in Escherichia coli LS5218 and its effects on the production of polyhydroxyalkanoates using beechwood xylan as a feedstock.

    Science.gov (United States)

    Salamanca-Cardona, Lucia; Scheel, Ryan A; Lundgren, Benjamin R; Stipanovic, Arthur J; Matsumoto, Ken'ichiro; Taguchi, Seiichi; Nomura, Christopher T

    2014-01-01

    Engineering of microorganisms to directly utilize plant biomass as a feedstock for the biosynthesis of value-added products such as bioplastics is the aim of consolidated bioprocessing. In previous research we successfully engineered E. coli LS5218 to produce polyhydroxyalkanoates (PHAs) from xylan. In this study we report further genetic modifications to Escherichia coli LS5218 in order to increase the lactic acid (LA) fraction in poly(lactic acid-co-3-hydroxyalkanoate) P(LA-co-HA) copolymers. Deletion of the pflA gene resulted in increased content of LA repeating units in the copolymers by over 3-fold compared with the wild type; however, this increase was offset by reduced yields in cell mass. Additionally, when acetate was used as a feedstock LA monomer incorporation reached 18.5 (mol%), which suggests that acetate can be used as a feedstock for the production of P(LA-co-HA) copolymers by E. coli.

  17. System characteristics and performance evaluation of a trailer-scale downdraft gasifier with different feedstock.

    Science.gov (United States)

    Balu, Elango; Chung, J N

    2012-03-01

    The main objective of this study is to investigate the thermal profiles of a trailer-scale gasifier in different zones during the course of gasification and also to elaborate on the design, characteristics and performance of the gasification system using different biomass feedstock. The purpose is to emphasize on the effectiveness of distributed power generation systems and demonstrate the feasibility of such gasification systems in real world scenarios, where the lingo-cellulosic biomass resources are widely available and distributed across the board. Experimental data on the thermal profiles with respect to five different zones in the gasifier and a comprehensive thermal-chemical equilibrium model to predict the syngas composition are presented in detail. Four different feedstock-pine wood, horse manure, red oak, and cardboard were evaluated. The effects of C, H, O content variations in the feedstock on the thermal profiles, and the efficiency and viability of the trailer-scale gasifier are also discussed. Copyright © 2012 Elsevier Ltd. All rights reserved.

  18. Assessing the potential of fatty acids produced by filamentous fungi as feedstock for biodiesel production.

    Science.gov (United States)

    Rivaldi, Juan Daniel; Carvalho, Ana Karine F; da Conceição, Leyvison Rafael V; de Castro, Heizir F

    2017-11-26

    Increased costs and limited availability of traditional lipid sources for biodiesel production encourage researchers to find more sustainable feedstock at low prices. Microbial lipid stands out as feedstock replacement for vegetable oil to convert fatty acid esters. In this study, the potential of three isolates of filamentous fungi (Mucor circinelloides URM 4140, M. hiemalis URM 4144, and Penicillium citrinum URM 4126) has been assessed as single-cell oil (SCO) producers. M. circinelloides 4140 had the highest biomass concentration with lipid accumulation of up to 28 wt% at 120 hr of cultivation. The profile of fatty acids revealed a high content of saturated (SFA) and monounsaturated fatty acids (MUFA), including palmitic (C16:0, 33.2-44.1 wt%) and oleic (C18:1, 20.7-31.2 wt%) acids, with the absence of polyunsaturated fatty acids (PUFA) having more than four double bonds. Furthermore, the predicted properties of biodiesel generated from synthesized SCOs have been estimated by using empirical models which were in accordance with the limits imposed by the USA (ASTM D6715), European Union (EN 14214), and Brazilian (ANP 45/2014) standards. These results suggest that the assessed filamentous fungus strains can be considered as alternative feedstock sources for high-quality biofuel production.

  19. Macroalgae as a Biomass Feedstock: A Preliminary Analysis

    Energy Technology Data Exchange (ETDEWEB)

    Roesijadi, Guritno; Jones, Susanne B.; Snowden-Swan, Lesley J.; Zhu, Yunhua

    2010-09-26

    A thorough of macroalgae analysis as a biofuels feedstock is warranted due to the size of this biomass resource and the need to consider all potential sources of feedstock to meet current biomass production goals. Understanding how to harness this untapped biomass resource will require additional research and development. A detailed assessment of environmental resources, cultivation and harvesting technology, conversion to fuels, connectivity with existing energy supply chains, and the associated economic and life cycle analyses will facilitate evaluation of this potentially important biomass resource.

  20. Mathematical modeling of (13)C label incorporation of the TCA cycle: the concept of composite precursor function.

    Science.gov (United States)

    Uffmann, Kai; Gruetter, Rolf

    2007-11-15

    A novel approach for the mathematical modeling of (13)C label incorporation into amino acids via the TCA cycle that eliminates the explicit calculation of the labeling of the TCA cycle intermediates is described, resulting in one differential equation per measurable time course of labeled amino acid. The equations demonstrate that both glutamate C4 and C3 labeling depend in a predictable manner on both transmitochondrial exchange rate, V(X), and TCA cycle rate, V(TCA). For example, glutamate C4 labeling alone does not provide any information on either V(X) or V(TCA) but rather a composite "flux". Interestingly, glutamate C3 simultaneously receives label not only from pyruvate C3 but also from glutamate C4, described by composite precursor functions that depend in a probabilistic way on the ratio of V(X) to V(TCA): An initial rate of labeling of glutamate C3 (or C2) being close to zero is indicative of a high V(X)/V(TCA). The derived analytical solution of these equations shows that, when the labeling of the precursor pool pyruvate reaches steady state quickly compared with the turnover rate of the measured amino acids, instantaneous labeling can be assumed for pyruvate. The derived analytical solution has acceptable errors compared with experimental uncertainty, thus obviating precise knowledge on the labeling kinetics of the precursor. In conclusion, a substantial reformulation of the modeling of label flow via the TCA cycle turnover into the amino acids is presented in the current study. This approach allows one to determine metabolic rates by fitting explicit mathematical functions to measured time courses.

  1. Development of whole core thermal-hydraulic analysis program ACT. 4. Incorporation of three-dimensional upper plenum model

    International Nuclear Information System (INIS)

    Ohshima, Hiroyuki

    2003-03-01

    The thermal-hydraulic analysis computer program ACT is under development for the evaluation of detailed flow and temperature fields in a core region of fast breeder reactors under various operation conditions. The purpose of this program development is to contribute not only to clarifying thermal hydraulic characteristics that cannot be revealed by experiments due to measurement difficulty but also to performing rational safety design and assessment. This report describes the incorporation of a three-dimensional upper plenum model to ACT and its verification study as part of the program development. To treat the influence of three-dimensional thermal-hydraulic behavior in a upper plenum on the in-core temperature field, the multi-dimensional general purpose thermal-hydraulic analysis program AQUA, which was developed and validated at JNC, was applied as the base of the upper plenum analysis module of ACT. AQUA enables to model the upper plenum configuration including immersed heat exchangers of the direct reactor auxiliary cooling system (DRACS). In coupling core analysis module that consists of the fuel-assembly and the inter-wrapper gap calculation parts with the upper plenum module, different types of computation mesh systems were jointed using the staggered quarter assembly mesh scheme. A coupling algorithm among core, upper plenum and heat transport system modules, which can keep mass, momentum and energy conservation, was developed and optimized in consideration of parallel computing. ACT was applied to analyzing a sodium experiment (PLANDTL-DHX) performed at JNC, which simulated the natural circulation decay heat removal under DRACS operation conditions for the program verification. From the calculation result, the validity of the improved program was confirmed. (author)

  2. HLA-B*39:06 Efficiently Mediates Type 1 Diabetes in a Mouse Model Incorporating Reduced Thymic Insulin Expression.

    Science.gov (United States)

    Schloss, Jennifer; Ali, Riyasat; Racine, Jeremy J; Chapman, Harold D; Serreze, David V; DiLorenzo, Teresa P

    2018-04-09

    Type 1 diabetes (T1D) is characterized by T cell-mediated destruction of the insulin-producing β cells of the pancreatic islets. Among the loci associated with T1D risk, those most predisposing are found in the MHC region. HLA-B*39:06 is the most predisposing class I MHC allele and is associated with an early age of onset. To establish an NOD mouse model for the study of HLA-B*39:06, we expressed it in the absence of murine class I MHC. HLA-B*39:06 was able to mediate the development of CD8 T cells, support lymphocytic infiltration of the islets, and confer T1D susceptibility. Because reduced thymic insulin expression is associated with impaired immunological tolerance to insulin and increased T1D risk in patients, we incorporated this in our model as well, finding that HLA-B*39:06-transgenic NOD mice with reduced thymic insulin expression have an earlier age of disease onset and a higher overall prevalence as compared with littermates with typical thymic insulin expression. This was despite virtually indistinguishable blood insulin levels, T cell subset percentages, and TCR Vβ family usage, confirming that reduced thymic insulin expression does not impact T cell development on a global scale. Rather, it will facilitate the thymic escape of insulin-reactive HLA-B*39:06-restricted T cells, which participate in β cell destruction. We also found that in mice expressing either HLA-B*39:06 or HLA-A*02:01 in the absence of murine class I MHC, HLA transgene identity alters TCR Vβ usage by CD8 T cells, demonstrating that some TCR Vβ families have a preference for particular class I MHC alleles. Copyright © 2018 by The American Association of Immunologists, Inc.

  3. A three-scale model for ionic solute transport in swelling clays incorporating ion-ion correlation effects

    Science.gov (United States)

    Le, Tien Dung; Moyne, Christian; Murad, Marcio A.

    2015-01-01

    A new three-scale model is proposed to describe the movement of ionic species of different valences in swelling clays characterized by three separate length scales (nano, micro, and macro) and two levels of porosity (nano- and micropores). At the finest (nano) scale the medium is treated as charged clay particles saturated by aqueous electrolyte solution containing monovalent and divalent ions forming the electrical double layer. A new constitutive law is constructed for the disjoining pressure based on the numerical resolution of non-local problem at the nanoscale which, in contrast to the Poisson-Boltzmann theory for point charge ions, is capable of capturing the short-range interactions between the ions due to their finite size. At the intermediate scale (microscale), the two-phase homogenized particle/electrolyte solution system is represented by swollen clay clusters (or aggregates) with the nanoscale disjoining pressure incorporated in a modified form of Terzaghi's effective principle. At the macroscale, the electro-chemical-mechanical couplings within clay clusters is homogenized with the ion transport in the bulk fluid lying in the micro pores. The resultant macroscopic picture is governed by a three-scale model wherein ion transport takes place in the bulk solution strongly coupled with the mechanics of the clay clusters which play the role of sources/sinks of mass to the bulk fluid associated with ion adsorption/desorption in the electrical double layer at the nanoscale. Within the context of the quasi-steady version of the multiscale model, wherein the electrolyte solution in the nanopores is assumed at instantaneous thermodynamic equilibrium with the bulk fluid in the micropores, we build-up numerically the ion-adsorption isotherms along with the constitutive law of the retardation coefficients of monovalent and divalent ions. In addition, the constitutive law for the macroscopic swelling pressure is reconstructed numerically showing patterns of

  4. Incorporation of the C-GOLDSTEIN efficient climate model into the GENIE framework: "eb_go_gs" configurations of GENIE

    Directory of Open Access Journals (Sweden)

    R. Marsh

    2011-11-01

    Full Text Available A computationally efficient, intermediate complexity ocean-atmosphere-sea ice model (C-GOLDSTEIN has been incorporated into the Grid ENabled Integrated Earth system modelling (GENIE framework. This involved decoupling of the three component modules that were re-coupled in a modular way, to allow replacement with alternatives and coupling of further components within the framework. The climate model described here (referred to as "eb_go_gs" for short is the most basic version of GENIE in which atmosphere, ocean and sea ice all play an active role. Among improvements on the original C-GOLDSTEIN model, latitudinal grid resolution is generalized to allow a wider range of surface grids to be used. The ocean, atmosphere and sea-ice components of the "eb_go_gs" configuration of GENIE are individually described, along with details of their coupling. The setup and results from simulations using four different meshes are presented. The four alternative meshes comprise the widely-used 36 × 36 equal-area-partitioning of the Earth surface with 16 depth layers in the ocean, a version in which horizontal and vertical resolution are doubled, a setup matching the horizontal resolution of the dynamic atmospheric component available in the GENIE framework, and a setup with enhanced resolution in high-latitude areas. Results are presented for a spin-up experiment with a baseline parameter set and wind forcing typically used for current studies in which "eb_go_gs" is coupled with the ocean biogeochemistry module of GENIE, as well as for an experiment with a modified parameter set, revised wind forcing, and additional cross-basin transport pathways (Indonesian and Bering Strait throughflows. The latter experiment is repeated with the four mesh variants, with common parameter settings throughout, except for time-step length. Selected state variables and diagnostics are compared in two regards: (i between simulations at lowest resolution that are obtained with the

  5. Stochastic optimization of a multi-feedstock lignocellulosic-based bioethanol supply chain under multiple uncertainties

    International Nuclear Information System (INIS)

    Osmani, Atif; Zhang, Jun

    2013-01-01

    An integrated multi-feedstock (i.e. switchgrass and crop residue) lignocellulosic-based bioethanol supply chain is studied under jointly occurring uncertainties in switchgrass yield, crop residue purchase price, bioethanol demand and sales price. A two-stage stochastic mathematical model is proposed to maximize expected profit by optimizing the strategic and tactical decisions. A case study based on ND (North Dakota) state in the U.S. demonstrates that in a stochastic environment it is cost effective to meet 100% of ND's annual gasoline demand from bioethanol by using switchgrass as a primary and crop residue as a secondary biomass feedstock. Although results show that the financial performance is degraded as variability of the uncertain parameters increases, the proposed stochastic model increasingly outperforms the deterministic model under uncertainties. The locations of biorefineries (i.e. first-stage integer variables) are insensitive to the uncertainties. Sensitivity analysis shows that “mean” value of stochastic parameters has a significant impact on the expected profit and optimal values of first-stage continuous variables. Increase in level of mean ethanol demand and mean sale price results in higher bioethanol production. When mean switchgrass yield is at low level and mean crop residue price is at high level, all the available marginal land is used for switchgrass cultivation. - Highlights: • Two-stage stochastic MILP model for maximizing profit of a multi-feedstock lignocellulosic-based bioethanol supply chain. • Multiple uncertainties in switchgrass yield, crop residue purchase price, bioethanol demand, and bioethanol sale price. • Proposed stochastic model outperforms the traditional deterministic model under uncertainties. • Stochastic parameters significantly affect marginal land allocation for switchgrass cultivation and bioethanol production. • Location of biorefineries is found to be insensitive to the stochastic environment

  6. Green biodiesel production: a review on feedstock, catalyst, monolithic reactor, and supercritical fluid technology

    Directory of Open Access Journals (Sweden)

    Rizo Edwin Gumba

    2016-09-01

    Full Text Available The advancement of alternative energy is primarily catalyzed by the negative environmental impacts and energy depletion caused by the excessive usage of fossil fuels. Biodiesel has emerged as a promising substitute to petrodiesel because it is biodegradable, less toxic, and reduces greenhouse gas emission. Apart from that, biodiesel can be used as blending component or direct replacements for diesel fuel in automotive engines. A diverse range of methods have been reported for the conversion of renewable feedstocks (vegetable oil or animal fat into biodiesel with transesterification being the most preferred method. Nevertheless, the cost of producing biodiesel is higher compared to fossil fuel, thus impeding its commercialization potentials. The limited source of reliable feedstock and the underdeveloped biodiesel production route have prevented the full-scale commercialization of biodiesel in many parts of the world. In a recent development, a new technology that incorporates monoliths as support matrices for enzyme immobilization in supercritical carbon dioxide (SC-CO2 for continuous biodiesel production has been proposed to solve the problem. The potential of SC-CO2 system to be applied in enzymatic reactors is not well documented and hence the purpose of this review is to highlight the previous studies conducted as well as the future direction of this technology.

  7. Modeling of oxygen incorporation in Th, ThC, and ThN by density functional theory calculations

    Science.gov (United States)

    Pérez Daroca, D.; Llois, A. M.; Mosca, H. O.

    2017-12-01

    Oxygen incorporation in nuclear fuel materials is an important issue deserving investigation due to its influence on thermophysical and structural properties. Even if there has been a renewed interest in thorium and thorium compounds in the last years, there is still not much research done on this topic. In this work, we study, by means of density functional theory calculations, the incorporation of oxygen in Th, ThC, and ThN. We analyze the electronic structure finding a characteristic peak to be attributed to oxygen incorporation. We also calculate incorporation and solution energies and obtain migration energies of oxygen through different paths finding that migration through vacancy sites is more energetically favorable than through interstitial ones.

  8. Forecasting the zeolite-containing catalyst activity in catalytic cracking technology taking into account the feedstock composition

    Science.gov (United States)

    Ivashkina, Elena; Nazarova, Galina; Shafran, Tatyana; Stebeneva, Valeriya

    2017-08-01

    The effect of the feedstock composition and the process conditions on the current catalyst activity in catalytic cracking technology using a mathematical model is performed in this research. The mathematical model takes into account the catalyst deactivation by coke for primary and secondary cracking reactions. The investigation results have shown that the feedstock has significant effect on the yield and the content of coke on the catalyst. Thus, the relative catalyst activity is significantly reduced by 7.5-10.7 %. With increasing the catalytic cracking temperature due to the catalyst flow temperature rising, the coke content and the yield per feedstock increase and the catalyst activity decreases by 5.3-7.7%. Rising the process temperature together with the catalyst circulation ratio contributes to increase of the coke yield per feedstock in the catalytic cracking and decrease of the coke content on the catalyst. It is connected with the catalyst flow rising to the riser and the contact time decreasing in the reaction zone. Also, the catalyst activity decreases in the range of 3.8-5.5% relatively to the regenerated catalyst activity (83 %).

  9. Response of a three-stage process for PHA production by mixed microbial cultures to feedstock shift: impact on polymer composition.

    Science.gov (United States)

    Duque, Anouk F; Oliveira, Catarina S S; Carmo, Inês T D; Gouveia, Ana R; Pardelha, Filipa; Ramos, Ana M; Reis, Maria A M

    2014-06-25

    Polyhydroxyalkanoates (PHA) can be produced by mixed microbial cultures (MMC) using a three-stage process. An attractive feature of MMC for PHA production is the ability to use waste/surplus feedstocks. In this study, the effect of a feedstock shift, mimicking a seasonal feedstock scenario and/or as a strategy for controlling polymer composition, on a MMC PHA production process was assessed using cheese whey (CW) and sugar cane molasses (SCM) as model feedstocks. The acidogenic stage responded immediately to the feedstock shift by changing the fermented products profile, with acetate and butyrate being the main acids produced from CW, while for SCM propionate and valerate were the dominant products. The fermentation process was then quite stable during long term operation. The PHA culture selection stage also responded quickly to the fermented feestocks shift, generating a polymer whose composition was linearly dependent on the concentration of HV and HB precursors produced in the acidogenic stage. The selected culture reached a maximum PHA content of 56% and 65% with fermented SCM and CW, respectively. Mixing fermented CW and SCM, in equal volume proportions, demonstrated the possibility of using different fermented feedstocks for tailoring polymer composition. Copyright © 2013 Elsevier B.V. All rights reserved.

  10. Advances in Modeling Streambank Stability by Incorporating the Mechanical and Hydrologic Effects of Woody and Herbaceous Riparian Vegetation

    Science.gov (United States)

    Simon, A.; Collison, A. J.

    2001-12-01

    Sediment is one of the principle pollutants of surface waters of the United States. Sediment derived from streambanks by mass failure is a significant contributor to water-quality and land management problems. Accurately modeling streambank stability and potential mitigation strategies using riparian vegetation involves quantifying the hydrologic and mechanical factors that control the driving and resisting forces imposed by bank material, ground and surface water and the vegetation. Stabilization of streambanks using riparian vegetation offers numerous potential benefits and some potential problems that are related to mechanical and hydrological effects that are rarely quantified. In this study mechanical reinforcement of various woody and herbaceous riparian species is quantified with in situ, field measurements of root tensile strength, root sizes and root distribution that are used to calculate increases in soil cohesion. Hydrological effects of vegetation are monitored at the Goodwin Creek Experimental Watershed, Mississippi using interception plots and tensiometers under three vegetative covers: cropped grass `control' cover, clumps of eastern gamma grass, and a deciduous woody-vegetation stand. The ARS Bank-Stability Model which accounts for complex bank geometries, up to five soil layers, positive and negative pore-water pressures and confining pressure due to streamflow is used to evaluate the effectiveness of various vegetative treatments based on the field data. The model is used to evaluate the individual and combined effects of vegetation on streambank stability. On April 4 th 2000 prolonged rainfall at the field site caused bank failure at the control cover plot, providing useful validation data for the analysis. The resulting factor of safety (Fs) values (incorporating both hydrological and mechanical effects) were 1.04, 1.64 and 2.18, respectively. Results show that the main contribution of the woody-vegetation to bank stability during the study

  11. Maximum fossil fuel feedstock replacement potential of petrochemicals via biorefineries

    NARCIS (Netherlands)

    Brehmer, B.; Boom, R.M.; Sanders, J.P.M.

    2009-01-01

    The search for feedstock replacement options within the petrochemical industry should logically be based upon non-fossil resources. Retaining the functionality of the biochemicals in biomass for use as chemical products and precursors can lead to a sizeable reduction of fossil fuel consumption. This

  12. Designing selection criteria for reed canarygrass as a bioenergy feedstock

    Science.gov (United States)

    Reed canarygrass (Phalaris arundinacea L.) is a perennial C3 grass with a circumglobal distribution in the northern hemisphere and adaptation to a wide range of environmental conditions. This species is currently under development as a bioenergy feedstock in both North America and Europe. Thus, the ...

  13. Lignocellulosic feedstock supply systems with intermodal and overseas transportation

    NARCIS (Netherlands)

    Hoefnagels, Ric; Searcy, E.; Kafferty, K.; Cornelissen, T.; Junginger, Martin; Jacobson, J.; Faaij, André

    2014-01-01

    With growing demand for internationally traded biomass, the logistic operations required to economically move biomass from the field or forest to end- users have become increasingly complex. To design cost effective and sustainable feedstock supply chains, it is important to understand the

  14. Lignin-containing Feedstock Hydrogenolysis for Biofuel Component Production

    Directory of Open Access Journals (Sweden)

    Elena Shimanskaya

    2018-01-01

    How to Cite: Shimanskaya, E.I., Stepacheva, A.A., Sulman, E.M., Rebrov, E.V., Matveeva, V.G. (2018. Lignin-containing Feedstock Hydrogenolysis for Biofuel Component Production. Bulletin of Chemical Reaction Engineering & Catalysis, 13 (1: 74-81 (doi:10.9767/bcrec.13.1.969.74-81

  15. Fatty acid profile of 25 alternative lipid feedstocks

    Science.gov (United States)

    This study reports the fatty acid profiles of 25 alternative lipid feedstocks for the production of bio-based fuels and chemicals. Lipids were extracted using hexane from oil-bearing seeds using a standard Soxhlet apparatus. Fatty acid profiles were measured using gas chromatography-flame ionization...

  16. The impact of silicon feedstock on the PV module cost

    NARCIS (Netherlands)

    del Coso, G.; del Cañizo, C.; Sinke, W.C.

    2010-01-01

    The impact of the use of new (solar grade) silicon feedstock materials on the manufacturing cost of wafer-based crystalline silicon photovoltaic modules is analyzed considering effects of material cost, efficiency of utilisation, and quality. Calculations based on data provided by European industry

  17. Biomass Program 2007 Program Peer Review - Feedstock Platform Summary

    Energy Technology Data Exchange (ETDEWEB)

    none,

    2009-10-27

    This document discloses the comments provided by a review panel at the U.S. Department of Energy Office of the Biomass Program Peer Review held on November 15-16, 2007 in Baltimore, MD and the Feedstock Platform Portfolio Peer Review held on August 21st through 23rd in Washington D.C.

  18. Ensuring Environmentally Sustainable Production of Dedicated Biomass Feedstocks

    Science.gov (United States)

    V.R. Tolbert; D.A. Mays; A. Houston; D.D. Tyler; C.H. Perry; K.E. Brooks; F.C. Thornton; B.R. Bock; J.D. Joslin; Carl C. Trettin; J. Isebrands

    2000-01-01

    Ensuring acceptance of dedicated biomass feedstocks by landowners, agricultural communities, environmental and public interest groups, requires that the environmental benefits, concerns, and risks associated with their production be quantified. Establishment and management measures to benefit soil and water quality are being identified by ongoing research. Field...

  19. A Landscape Vision for Sustainable Bioenergy Feedstock Production

    Science.gov (United States)

    Feedstock production for biofuel and other bioproducts is poised to rejuvenate rural economies, but may lead to long-term degradation of soil resources or other adverse and unintended environmental consequences if the practices are not developed in a sustainable manner. This presentation will examin...

  20. Transgenic perennial biofuel feedstocks and strategies for bioconfinement

    Science.gov (United States)

    The use of transgenic tools for the improvement of plant feedstocks will be required to realize the full economic and environmental benefits of cellulosic and other biofuels, particularly from perennial plants. Traits that are targets for improvement of biofuels crops include he...

  1. Renewable feedstocks: the problem of catalyst deactivation and its mitigation

    NARCIS (Netherlands)

    Lange, Jean Paul

    2015-01-01

    Much research has been carried out in the last decade to convert bio-based feedstock into fuels and chemicals. Most of the research focuses on developing active and selective catalysts, with much less attention devoted to their long-term stability. This Review considers the main challenges in

  2. Analysis of PWR control rod ejection accident with the coupled code system SKETCH-INS/TRACE by incorporating pin power reconstruction model

    International Nuclear Information System (INIS)

    Nakajima, T.; Sakai, T.

    2010-01-01

    The pin power reconstruction model was incorporated in the 3-D nodal kinetics code SKETCH-INS in order to produce accurate calculation of three-dimensional pin power distributions throughout the reactor core. In order to verify the employed pin power reconstruction model, the PWR MOX/UO 2 core transient benchmark problem was analyzed with the coupled code system SKETCH-INS/TRACE by incorporating the model and the influence of pin power reconstruction model was studied. SKETCH-INS pin power distributions for 3 benchmark problems were compared with the PARCS solutions which were provided by the host organisation of the benchmark. SKETCH-INS results were in good agreement with the PARCS results. The capability of employed pin power reconstruction model was confirmed through the analysis of benchmark problems. A PWR control rod ejection benchmark problem was analyzed with the coupled code system SKETCH-INS/ TRACE by incorporating the pin power reconstruction model. The influence of pin power reconstruction model was studied by comparing with the result of conventional node averaged flux model. The results indicate that the pin power reconstruction model has significant effect on the pin powers during transient and hence on the fuel enthalpy

  3. Extended Fitts' model of pointing time in eye-gaze input system - Incorporating effects of target shape and movement direction into modeling.

    Science.gov (United States)

    Murata, Atsuo; Fukunaga, Daichi

    2018-04-01

    This study attempted to investigate the effects of the target shape and the movement direction on the pointing time using an eye-gaze input system and extend Fitts' model so that these factors are incorporated into the model and the predictive power of Fitts' model is enhanced. The target shape, the target size, the movement distance, and the direction of target presentation were set as within-subject experimental variables. The target shape included: a circle, and rectangles with an aspect ratio of 1:1, 1:2, 1:3, and 1:4. The movement direction included eight directions: upper, lower, left, right, upper left, upper right, lower left, and lower right. On the basis of the data for identifying the effects of the target shape and the movement direction on the pointing time, an attempt was made to develop a generalized and extended Fitts' model that took into account the movement direction and the target shape. As a result, the generalized and extended model was found to fit better to the experimental data, and be more effective for predicting the pointing time for a variety of human-computer interaction (HCI) task using an eye-gaze input system. Copyright © 2017. Published by Elsevier Ltd.

  4. Projecting future grassland productivity to assess thesustainability of potential biofuel feedstock areas in theGreater Platte River Basin

    Science.gov (United States)

    Gu, Yingxin; Wylie, Bruce K.; Boyte, Stephen; Phuyal, Khem P.

    2014-01-01

    This study projects future (e.g., 2050 and 2099) grassland productivities in the Greater Platte River Basin (GPRB) using ecosystem performance (EP, a surrogate for measuring ecosystem productivity) models and future climate projections. The EP models developed from a previous study were based on the satellite vegetation index, site geophysical and biophysical features, and weather and climate drivers. The future climate data used in this study were derived from the National Center for Atmospheric Research Community Climate System Model 3.0 ‘SRES A1B’ (a ‘middle’ emissions path). The main objective of this study is to assess the future sustainability of the potential biofuel feedstock areas identified in a previous study. Results show that the potential biofuel feedstock areas (the more mesic eastern part of the GPRB) will remain productive (i.e., aboveground grassland biomass productivity >2750 kg ha−1 year−1) with a slight increasing trend in the future. The spatially averaged EPs for these areas are 3519, 3432, 3557, 3605, 3752, and 3583 kg ha−1 year−1 for current site potential (2000–2008 average), 2020, 2030, 2040, 2050, and 2099, respectively. Therefore, the identified potential biofuel feedstock areas will likely continue to be sustainable for future biofuel development. On the other hand, grasslands identified as having no biofuel potential in the drier western part of the GPRB would be expected to stay unproductive in the future (spatially averaged EPs are 1822, 1691, 1896, 2306, 1994, and 2169 kg ha−1 year−1 for site potential, 2020, 2030, 2040, 2050, and 2099). These areas should continue to be unsuitable for biofuel feedstock development in the future. These future grassland productivity estimation maps can help land managers to understand and adapt to the expected changes in future EP in the GPRB and to assess the future sustainability and feasibility of potential biofuel feedstock areas.

  5. Fatty acid profile as a basis for screening feedstocks for biodiesel production

    Science.gov (United States)

    Fatty acid (FA) profile was used as a screening tool for the selection of feedstocks high in monounsaturated content for evaluation as biodiesel. The feedstocks were ailanthus (Ailanthus altissima), anise (Pimpinella anisum), arugula (Eruca vesicaria), camelina (Camelina sativa), coriander (Coriandr...

  6. Fatty acid composition as a tool for screening alternative feedstocks for production of biodiesel

    Science.gov (United States)

    Fatty acid (FA) composition was used as a screening tool for the selection of feedstocks high in monounsaturated content for evaluation as biodiesel. The feedstocks were ailanthus (Ailanthus altissima), anise (Pimpinella anisum), arugula (Eruca vesicaria), camelina (Camelina sativa), coriander (Cori...

  7. Developing an Integrated Design Model Incorporating Technology Philosophy for the Design of Healthcare Environments: A Case Analysis of Facilities for Psychogeriatric and Psychiatric Care in The Netherlands

    NARCIS (Netherlands)

    J. van Hoof; M.J. Verkerk

    2013-01-01

    van Hoof, J., Verkerk, M.J. (2013) Developing an Integrated Design Model Incorporating Technology Philosophy for the Design of Healthcare Environments: A Case Analysis of Facilities for Psychogeriatric and Psychiatric Care in The Netherlands. Technology in Society 35(1):1-13

  8. Impact of Biodiesel Fuels on Air Quality and Human Health: Task 1 Report; Incorporate Biodiesel Data into Vehicle Emissions Databases for Modeling

    Energy Technology Data Exchange (ETDEWEB)

    Lindhjem, C.; Pollack, A.

    2003-05-01

    This document is the Task 1 report for the NREL"Impact of Biodiesel Fuels on Air Quality and Human Health" study. This report provides a discussion and analysis of the available biodiesel test data, and makes recommendations for how biodiesel effects on pollutant mass emissions as well as chemical composition should be incorporated into emission inventories for use in air quality modeling.

  9. Landscape-scale parameterization of a tree-level forest growth model: a k-nearest neighbor imputation approach incorporating LiDAR data

    Science.gov (United States)

    Michael J. Falkowski; Andrew T. Hudak; Nicholas L. Crookston; Paul E. Gessler; Edward H. Uebler; Alistair M. S. Smith

    2010-01-01

    Sustainable forest management requires timely, detailed forest inventory data across large areas, which is difficult to obtain via traditional forest inventory techniques. This study evaluated k-nearest neighbor imputation models incorporating LiDAR data to predict tree-level inventory data (individual tree height, diameter at breast height, and...

  10. A corrected model for static and dynamic electromechanical instability of narrow nanotweezers: Incorporation of size effect, surface layer and finite dimensions

    Science.gov (United States)

    Koochi, Ali; Hosseini-Toudeshky, Hossein; Abadyan, Mohamadreza

    2018-03-01

    Herein, a corrected theoretical model is proposed for modeling the static and dynamic behavior of electrostatically actuated narrow-width nanotweezers considering the correction due to finite dimensions, size dependency and surface energy. The Gurtin-Murdoch surface elasticity in conjunction with the modified couple stress theory is employed to consider the coupling effect of surface stresses and size phenomenon. In addition, the model accounts for the external force corrections by incorporating the impact of narrow width on the distribution of Casimir attraction, van der Waals (vdW) force and the fringing field effect. The proposed model is beneficial for the precise modeling of the narrow nanotweezers in nano-scale.

  11. Evaluating the Potential of Marginal Land for Cellulosic Feedstock Production and Carbon Sequestration in the United States.

    Science.gov (United States)

    Emery, Isaac; Mueller, Steffen; Qin, Zhangcai; Dunn, Jennifer B

    2017-01-03

    Land availability for growing feedstocks at scale is a crucial concern for the bioenergy industry. Feedstock production on land not well-suited to growing conventional crops, or marginal land, is often promoted as ideal, although there is a poor understanding of the qualities, quantity, and distribution of marginal lands in the United States. We examine the spatial distribution of land complying with several key marginal land definitions at the United States county, agro-ecological zone, and national scales, and compare the ability of both marginal land and land cover data sets to identify regions for feedstock production. We conclude that very few land parcels comply with multiple definitions of marginal land. Furthermore, to examine possible carbon-flow implications of feedstock production on land that could be considered marginal per multiple definitions, we model soil carbon changes upon transitions from marginal cropland, grassland, and cropland-pastureland to switchgrass production for three marginal land-rich counties. Our findings suggest that total soil organic carbon changes per county are small, and generally positive, and can influence life-cycle greenhouse gas emissions of switchgrass ethanol.

  12. Prospects for using multi-walled carbon nanotubes formed from renewable feedstock in hydrogen energy

    International Nuclear Information System (INIS)

    Onishchenko, D. V.

    2013-01-01

    Mechanoactivation of amorphous carbon synthesized from renewable feedstock promotes formation of multi-walled carbon nanotubes, and the best results were obtained using the feedstock of sphagnum moss. It is shown that the carbon nanotubes formed from different plant feedstock have a high sorption capacity with respect to hydrogen. (author)

  13. Hydrodeoxygenation of fast-pyrolysis bio-oils from various feedstocks using carbon-supported catalysts

    Science.gov (United States)

    While much work has been accomplished in developing hydrodeoxygenation technologies for bio-oil upgrading, very little translation has occurred to other biomass feedstocks and feedstock processing technologies. In this paper, we sought to elucidate the relationships between the feedstock type and th...

  14. 26 CFR 48.4082-7 - Kerosene; exemption for feedstock purposes.

    Science.gov (United States)

    2010-04-01

    ... 26 Internal Revenue 16 2010-04-01 2010-04-01 true Kerosene; exemption for feedstock purposes. 48..., Tread Rubber, and Taxable Fuel Taxable Fuel § 48.4082-7 Kerosene; exemption for feedstock purposes. (a... kerosene for use for a feedstock purpose. (b) Definitions. The following definitions apply to this section...

  15. Forest based biomass for energy in Uganda: Stakeholder dynamics in feedstock production

    International Nuclear Information System (INIS)

    Hazelton, Jennifer A.; Windhorst, Kai; Amezaga, Jaime M.

    2013-01-01

    Insufficient energy supply and low levels of development are closely linked. Both are major issues in Uganda where growing demand cannot be met by overstretched infrastructure and the majority still rely on traditional biomass use. Uganda's renewable energy policy focuses on decentralised sources including modern biomass. In this paper, stakeholder dynamics and potential socio-economic impacts of eight modern bioenergy feedstock production models in Uganda are considered, and key considerations for future planning provided. For these models the main distinctions were land ownership (communal or private) and feedstock type (by-product or plantation). Key social issues varied by value chain (corporate, government or farmer/NGO), and what production arrangement was in place (produced for own use or sale). Small, privately owned production models can be profitable but are unlikely to benefit landless poor and, if repeated without strategic planning, could result in resource depletion. Larger projects can have greater financial benefits, though may have longer term natural resource impacts felt by adjacent communities. Bioenergy initiatives which allow the rural poor to participate through having a collaborative stake, rather than receiving information, and provide opportunities for the landless are most likely to result in socio-economic rural development to meet policy goals. The structured approach to understanding stakeholder dynamics used was found to be robust and sufficiently adaptable to provide meaningful analysis. In conclusion; local, context-specific planning and assessment for bioenergy projects, where all stakeholders have the opportunity to be collaborators in the process throughout its full lifecycle, is required to achieve rural development objectives. -- Highlights: • Stakeholder dynamics and socio-economics in 8 Ugandan bioenergy projects considered. • Key distinctions were ownership, feedstock, value chain and production arrangement. • Small

  16. Feedstock Interface Fy2017 Q3 Report

    Energy Technology Data Exchange (ETDEWEB)

    Carpenter, Danny [National Renewable Energy Lab. (NREL), Golden, CO (United States); Howe, Daniel [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Westover, Tyler [Idaho National Lab. (INL), Idaho Falls, ID (United States); Klinger, HJordan [Idaho National Lab. (INL), Idaho Falls, ID (United States); Hernandez, Sergio [Idaho National Lab. (INL), Idaho Falls, ID (United States)

    2017-07-10

    This report summarized the results obtained in FY2017 Q3 of a collaborative effort between researchers at NREL, PNNL, and INL to develop rapid screening methods and models to predict the fact pyrolysis conversion performance of a range of biomass materials.

  17. Analytical characterization of mannosylerythritol lipid biosurfactants produced by biosynthesis based on feedstock sources from the agrofood industry.

    Science.gov (United States)

    Onghena, Matthias; Geens, Tinne; Goossens, Eliane; Wijnants, Marc; Pico, Yolanda; Neels, Hugo; Covaci, Adrian; Lemiere, Filip

    2011-05-01

    Mannosylerythritol lipids (MELs) are currently one of the most promising biosurfactants because of their multifunctional applications and good biodegradability. Depending on the yeast strain and the feedstock used for the fermentation process, structural variations in the MELs obtained occur. Therefore, MELs produced by Pseudozyma aphidis DSMZ 70725 with a soybean oil feedstock were characterized by chromatography and mass spectrometry (MS). Column chromatography with silica provided fractionation of the different types of MEL. High-performance liquid chromatography combined with MS was employed for the analysis of the MEL fractions and crude mixtures. A characteristic MS pattern for the MELs was obtained and indications of the presence of new MEL homologues, showing the incorporation of longer and more unsaturated fatty acid chains than previously reported, were given. Gas chromatography-MS analysis confirmed the presence of such unsaturated fatty acid chains in the MELs, demonstrating the incorporation of fatty acids with lengths ranging from C(8) to C(14) and with up to two unsaturations per chain. The incorporation of C(16) and C(18) fatty acid chains requires further investigation. MS/MS data allowed the unambiguous identification of the fatty acids present in the MELs. The product ion spectra also revealed the presence of a new isomeric class of MELs, bearing an acetyl group on the erythritol moiety.

  18. A family of spatial interaction models incorporating information flows and choice set constraints applied to U.S. interstate labor flows.

    Science.gov (United States)

    Smith, T R; Slater, P B

    1981-01-01

    "A new family of migration models belonging to the elimination by aspects family is examined, with the spatial interaction model shown to be a special case. The models have simple forms; they incorporate information flow processes and choice set constraints; they are free of problems raised by the Luce Choice Axiom; and are capable of generating intransitive flows. Preliminary calibrations using the Continuous Work History Sample [time] series data indicate that the model fits the migration data well, while providing estimates of interstate job message flows. The preliminary calculations also indicate that care is needed in assuming that destination [attraction] are independent of origins." excerpt

  19. Dynamic impacts of high oil prices on the bioethanol and feedstock markets

    International Nuclear Information System (INIS)

    Cha, Kyung Soo; Bae, Jeong Hwan

    2011-01-01

    This study investigates the impacts of high international oil prices on the bioethanol and corn markets in the US. Between 2007 and 2008, the prices of major grain crops had increased sharply, reflecting the rise in international oil prices. These dual price shocks had caused substantial harm to the global economy. Employing a structural vector auto-regression model (SVAR), we analyze how increases in international oil prices could impact the prices of and demand for corn, which is used as a major bioethanol feedstock in the US. The results indicate that an increase in the oil price would increase bioethanol demand for corn and corn prices in the short run and that corn prices would stabilize in the long run as corn exports and feedstock demand for corn decline. Consequently, policies supporting biofuels should encourage the use of bioethanol co-products for feed and the development of marginal land to mitigate increases in the feedstock price. - Research highlights: → World economy experienced 'dual shocks', which were caused by skyrocketed oil prices and grain prices between 2007 and 2008. → Sharp increases in ethanol production in response to high oil prices were considered as a major driving force to 'ag-flation' in the United States. → Applying a time series econometric tool, called the 'structural vector auto-regression model', we evaluated relationship between ethanol production and corn prices. → The result shows that ethanol production affects corn prices in the short run, while corn prices are lowered as other corn demands (feed for livestock or export demand) decline in the long run.

  20. Lignocellulosic ethanol in India: Prospects, challenges and feedstock availability.

    Science.gov (United States)

    Sukumaran, Rajeev K; Surender, Vikram Joshua; Sindhu, Raveendran; Binod, Parameshwaran; Janu, Kanakambaran Usha; Sajna, Kuttavan Valappil; Rajasree, Kuni Parambil; Pandey, Ashok

    2010-07-01

    India has a pressing need for renewable transportation fuels and bio-ethanol is considered as one of the most important options. Currently the country mandates use of 5% ethanol blending in motor gasoline in several states. The ethanol for this is mainly sourced from molasses feedstock, but this is barely sufficient to meet the current demand. Lignocellulosic biomass is the alternative but the availability of this resource is poorly documented. Also the technologies for ethanol production from lignocellulosic biomass are under preliminary stages of development which warrants extensive R&D in this field. The review discusses the current status of molasses based ethanol production in India and its limitations, the state of technologies for second generation ethanol production and the availability of feedstock for bio-ethanol production. Copyright 2009 Elsevier Ltd. All rights reserved.

  1. Demand and supply of hydrogen as chemical feedstock in USA

    Science.gov (United States)

    Huang, C. J.; Tang, K.; Kelley, J. H.; Berger, B. J.

    1979-01-01

    Projections are made for the demand and supply of hydrogen as chemical feedstock in USA. Industrial sectors considered are petroleum refining, ammonia synthesis, methanol production, isocyanate manufacture, edible oil processing, coal liquefaction, fuel cell electricity generation, and direct iron reduction. Presently, almost all the hydrogen required is produced by reforming of natural gas or petroleum fractions. Specific needs and emphases are recommended for future research and development to produce hydrogen from other sources to meet the requirements of these industrial sectors. The data and the recommendations summarized in this paper are based on the Workshop 'Supply and Demand of Hydrogen as Chemical Feedstock' held at the University of Houston on December 12-14, 1977.

  2. Potential feedstock sources for ethanol production in Florida

    Energy Technology Data Exchange (ETDEWEB)

    Rahmani, Mohammad [Univ. of Florida, Gainesville, FL (United States); Hodges, Alan [Univ. of Florida, Gainesville, FL (United States)

    2015-10-01

    This study presents information on the potential feedstock sources that may be used for ethanol production in Florida. Several potential feedstocks for fuel ethanol production in Florida are discussed, such as, sugarcane, corn, citrus byproducts and sweet sorghum. Other probable impacts need to be analyzed for sugarcane to ethanol production as alternative uses of sugarcane may affect the quantity of sugar production in Florida. While citrus molasses is converted to ethanol as an established process, the cost of ethanol is higher, and the total amount of citrus molasses per year is insignificant. Sorghum cultivars have the potential for ethanol production. However, the agricultural practices for growing sweet sorghum for ethanol have not been established, and the conversion process must be tested and developed at a more expanded level. So far, only corn shipped from other states to Florida has been considered for ethanol production on a commercial scale. The economic feasibility of each of these crops requires further data and technical analysis.

  3. Effects of feedstocks on the process integration of biohydrogen production

    Energy Technology Data Exchange (ETDEWEB)

    Foglia, Domenico; Wukovits, Walter; Friedl, Anton [Vienna University of Technology, Vienna (Austria); Ljunggren, Mattias; Zacchi, Guido [Lund University, P. O. Box 124, Lund (Sweden); Urbaniec, Krzysztof; Markowski, Mariusz [Warsaw University of Technology, Plock (Poland)

    2011-08-15

    Future production of hydrogen must be sustainable. To obtain it, renewable resources have to be employed for its production. Fermentation of biomasses could be a viable way. The process evaluated is a two-step fermentation to produce hydrogen from biomass. Process options with barley straws, PSP, and thick juice as feedstocks have been compared on the basis of process balances. Aspen Plus has been used to calculate mass and energy balances taking into account the integration of the process. Results show that the production of hydrogen as energy carrier is technically feasible with all the considered feedstocks and thanks to heat integration, second generation biomass (PSP and barley straws) are competitive with food crops (thick juice). (orig.)

  4. Processes for liquefying carbonaceous feedstocks and related compositions

    Energy Technology Data Exchange (ETDEWEB)

    MacDonnell, Frederick M.; Dennis, Brian H.; Billo, Richard E.; Priest, John W.

    2017-02-28

    Methods for the conversion of lignites, subbituminous coals and other carbonaceous feedstocks into synthetic oils, including oils with properties similar to light weight sweet crude oil using a solvent derived from hydrogenating oil produced by pyrolyzing lignite are set forth herein. Such methods may be conducted, for example, under mild operating conditions with a low cost stoichiometric co-reagent and/or a disposable conversion agent.

  5. Kurdistan crude oils as feedstock for production of aromatics

    Directory of Open Access Journals (Sweden)

    Abdulsalam R. Karim

    2017-05-01

    Full Text Available Crude oils from various locations in Iraqi Kurdistan were fully evaluated, so that enables refiners to improve their operation by selecting the best crude oil that yields high naphtha content to be used as a catalytic reforming feedstock after determination of total sulfur content and then de sulfurizing them, then cyclizing or reforming these sweet naphtha cuts to produce aromatic fractions which can be split into benzene, toluene, and xylenes.

  6. Expected international demand for woody and herbaceous feedstock

    Energy Technology Data Exchange (ETDEWEB)

    Lamers, Patrick [Idaho National Lab. (INL), Idaho Falls, ID (United States); Jacobson, Jacob [Idaho National Lab. (INL), Idaho Falls, ID (United States); Mohammad, Roni [Idaho National Lab. (INL), Idaho Falls, ID (United States); Wright, Christopher [Idaho National Lab. (INL), Idaho Falls, ID (United States)

    2015-03-01

    The development of a U.S. bioenergy market and ultimately ‘bioeconomy’ has primarily been investigated with a national focus. Limited attention has been given to the potential impacts of international market developments. The goal of this project is to advance the current State of Technology of a single biorefinery to the global level providing quantitative estimates on how international markets may influence the domestic feedstock supply costs. The scope of the project is limited to feedstock that is currently available and new crops being developed to be used in a future U.S. bioeconomy including herbaceous residues (e.g., corn stover), woody biomass (e.g., pulpwood), and energy crops (e.g., switchgrass). The timeframe is set to the periods of 2022, 2030, and 2040 to align with current policy targets (e.g., the RFS2) and future updates of the Billion Ton data. This particular milestone delivers demand volumes for generic woody and herbaceous feedstocks for the main (net) importing regions along the above timeframes. The regional focus of the study is the European Union (EU), currently the largest demand region for U.S. pellets made from pulpwood and forest residues. The pellets are predominantly used in large-scale power plants (>5MWel) in the United Kingdom (UK), the Netherlands (NL), Belgium (BE), and Denmark (DK).

  7. Physiochemical characterization of briquettes made from different feedstocks.

    Science.gov (United States)

    Karunanithy, C; Wang, Y; Muthukumarappan, K; Pugalendhi, S

    2012-01-01

    Densification of biomass can address handling, transportation, and storage problems and also lend itself to an automated loading and unloading of transport vehicles and storage systems. The purpose of this study is to compare the physicochemical properties of briquettes made from different feedstocks. Feedstocks such as corn stover, switchgrass, prairie cord grass, sawdust, pigeon pea grass, and cotton stalk were densified using a briquetting system. Physical characterization includes particle size distribution, geometrical mean diameter (GMD), densities (bulk and true), porosity, and glass transition temperature. The compositional analysis of control and briquettes was also performed. Statistical analyses confirmed the existence of significant differences in these physical properties and chemical composition of control and briquettes. Correlation analysis confirms the contribution of lignin to bulk density and durability. Among the feedstocks tested, cotton stalk had the highest bulk density of 964 kg/m(3) which is an elevenfold increase compared to control cotton stalk. Corn stover and pigeon pea grass had the highest (96.6%) and lowest (61%) durability.

  8. Co-liquefaction of spent coffee grounds and lignocellulosic feedstocks.

    Science.gov (United States)

    Yang, Linxi; He, Quan Sophia; Havard, Peter; Corscadden, Kenneth; Xu, Chunbao Charles; Wang, Xuan

    2017-08-01

    Co-liquefaction of spent coffee grounds (SCG) with paper filter (PF), corn stalk (CS) and white pine bark (WPB) respectively, was examined in subcritical water for bio-crude oil production. The optimum reaction temperature was 250°C, and the mixing biomass ratio was 1:1. SCG and CS was identified to be the best feedstock combination with a significant positive synergetic effect in the co-liquefaction process with 5% NaOH as a catalyst. The yield of bio-crude oil was increased by 20.9% compared to the mass averaged yield from two feedstocks, and the oil quality was also improved in terms of viscosity and relative molecular mass. A negative effect presented in the co-liquefaction of SCG/WPB. The resulting bio-crude oils were characterized by elemental analyzer, GC-MS, GPC and viscometer, indicating that mixing feedstock in the co-liquefaction process also influenced the higher heating value (HHV), viscosity, molecular mass and chemical composition of bio-crude oil. Copyright © 2017 Elsevier Ltd. All rights reserved.

  9. Physiochemical Characterization of Briquettes Made from Different Feedstocks

    Directory of Open Access Journals (Sweden)

    C. Karunanithy

    2012-01-01

    Full Text Available Densification of biomass can address handling, transportation, and storage problems and also lend itself to an automated loading and unloading of transport vehicles and storage systems. The purpose of this study is to compare the physicochemical properties of briquettes made from different feedstocks. Feedstocks such as corn stover, switchgrass, prairie cord grass, sawdust, pigeon pea grass, and cotton stalk were densified using a briquetting system. Physical characterization includes particle size distribution, geometrical mean diameter (GMD, densities (bulk and true, porosity, and glass transition temperature. The compositional analysis of control and briquettes was also performed. Statistical analyses confirmed the existence of significant differences in these physical properties and chemical composition of control and briquettes. Correlation analysis confirms the contribution of lignin to bulk density and durability. Among the feedstocks tested, cotton stalk had the highest bulk density of 964 kg/m3 which is an elevenfold increase compared to control cotton stalk. Corn stover and pigeon pea grass had the highest (96.6% and lowest (61% durability.

  10. Sucrose Is a Promising Feedstock for the Synthesis of the Platform Chemical Hydroxymethylfurfural

    Directory of Open Access Journals (Sweden)

    David Steinbach

    2018-03-01

    Full Text Available Hydroxymethylfurfural (HMF has an outstanding position among bio-based platform chemicals, because high-value polymer precursors and fuel additives can be derived from HMF. Unfortunately, the large-scale industrial production of HMF is not yet realized. An open research question is the choice of hexose feedstock material. In this study, we used the highly available disaccharide sucrose for HMF synthesis. The conversion of sucrose was catalyzed by sulfuric acid in water media. Experiments were conducted at temperatures of 180, 200, and 220 °C with reaction times of 2–24 min. A carbon balance showed that the yield of unwanted side products rose strongly with temperature. We also developed a kinetic model for the conversion of sucrose, involving nine first-order reactions, to uncover the kinetics of the main reaction pathways. Within this model, HMF is produced exclusively via the dehydration of fructose. Glucose isomerizes slowly to fructose. Side products arise simultaneously from glucose, fructose, and HMF. A pathway from hexoses to xylose via reverse aldol reaction was also included in the model. We believe that sucrose is the ideal feedstock for large-scale production of HMF because it is more abundant than fructose, and easier to process than sugars obtained from lignocellulosic biomass.

  11. Feeding a sustainable chemical industry: do we have the bioproducts cart before the feedstocks horse?

    Science.gov (United States)

    Dale, Bruce E

    2017-09-21

    A sustainable chemical industry cannot exist at scale without both sustainable feedstocks and feedstock supply chains to provide the raw materials. However, most current research focus is on producing the sustainable chemicals and materials. Little attention is given to how and by whom sustainable feedstocks will be supplied. In effect, we have put the bioproducts cart before the sustainable feedstocks horse. For example, bulky, unstable, non-commodity feedstocks such as crop residues probably cannot supply a large-scale sustainable industry. Likewise, those who manage land to produce feedstocks must benefit significantly from feedstock production, otherwise they will not participate in this industry and it will never grow. However, given real markets that properly reward farmers, demand for sustainable bioproducts and bioenergy can drive the adoption of more sustainable agricultural and forestry practices, providing many societal "win-win" opportunities. Three case studies are presented to show how this "win-win" process might unfold.

  12. Manipulating microRNAs for improved biomass and biofuels from plant feedstocks.

    Science.gov (United States)

    Trumbo, Jennifer Lynn; Zhang, Baohong; Stewart, Charles Neal

    2015-04-01

    Petroleum-based fuels are nonrenewable and unsustainable. Renewable sources of energy, such as lignocellulosic biofuels and plant metabolite-based drop-in fuels, can offset fossil fuel use and reverse environmental degradation through carbon sequestration. Despite these benefits, the lignocellulosic biofuels industry still faces many challenges, including the availability of economically viable crop plants. Cell wall recalcitrance is a major economic barrier for lignocellulosic biofuels production from biomass crops. Sustainability and biomass yield are two additional, yet interrelated, foci for biomass crop improvement. Many scientists are searching for solutions to these problems within biomass crop genomes. MicroRNAs (miRNAs) are involved in almost all biological and metabolic process in plants including plant development, cell wall biosynthesis and plant stress responses. Because of the broad functions of their targets (e.g. auxin response factors), the alteration of plant miRNA expression often results in pleiotropic effects. A specific miRNA usually regulates a biologically relevant bioenergy trait. For example, relatively low miR156 overexpression leads to a transgenic feedstock with enhanced biomass and decreased recalcitrance. miRNAs have been overexpressed in dedicated bioenergy feedstocks such as poplar and switchgrass yielding promising results for lignin reduction, increased plant biomass, the timing of flowering and response to harsh environments. In this review, we present the status of miRNA-related research in several major biofuel crops and relevant model plants. We critically assess published research and suggest next steps for miRNA manipulation in feedstocks for increased biomass and sustainability for biofuels and bioproducts. © 2015 Society for Experimental Biology, Association of Applied Biologists and John Wiley & Sons Ltd.

  13. Comparative life-cycle assessments for biomass-to-ethanol production from different regional feedstocks.

    Science.gov (United States)

    Kemppainen, Amber J; Shonnard, David R

    2005-01-01

    This study compares life-cycle (cradle-to-gate) energy consumption and environmental impacts for producing ethanol via fermentation-based processes starting with two lignocellulosic feedstocks: virgin timber resources or recycled newsprint from an urban area. The life-cycle assessment in this study employed a novel combination of computer-aided tools. These tools include fermentation process simulation coupled with an impact assessment software tool for the manufacturing process life-cycle stage impacts. The process simulation file was provided by the National Renewable Energy Laboratory (NREL) and was modified slightly to accommodate these different feedstocks. For the premanufacturing process life-cycle stage impacts, such as the fuels and process chemicals used, transportation, and some preparatory steps (wood chipping, etc.), a life-cycle inventory database (the Boustead Model) coupled with an impact assessment software tool were used (the Environmental Fate and Risk Assessment Tool). The Newsprint process has a slightly lower overall composite environmental index (created from eight impact categories) compared to the Timber process. However, the Timber process consumes less electricity, produces fewer emissions in total, and has less of a human health impact. The amount of life-cycle fossil energy required to produce ethanol is 14% of the energy content of the product, making the overall efficiency 86%. Process improvement strategies were evaluated for both feedstock processes, including recycle of reactor vent air and heat integration. Heat integration has the greatest potential to reduce fossil-derived energy consumption, to an extent that fossil-derived energy over the life cycle is actually saved per unit of ethanol produced. These energy efficiency values are superior to those observed in conventional fossil-based transportation fuels.

  14. Overview of feedstock research in the United States, Canada, and Brazil

    Energy Technology Data Exchange (ETDEWEB)

    Ferrell, J. [Department of Energy, Washington, DC (United States); Tardif, M.L. [CANMET, Ottawa, Ontario (Canada); Couto, L. [Universidade Federal de Vicosa (Brazil); Garca, L.R. [Centro Nacional de Pesquisa de Florestas, Colombo (Brazil); Betters, D. [Colorado State Univ., Fort Collins, CO (United States); Ashworth, J. [Meridian Corp., Alexandria, VA (United States)

    1993-12-31

    This is an overview of the current biomass feedstock efforts in Brazil, Canada, and the United States. The report from Brazil provides an historical perspective of incentive programs, the charcoal and fuelwood energy programs, the alcohol program, and other biomass energy efforts. The efforts in Brazil, particularly with the sugar cane to ethanol and the charcoal and fuelwood programs, dwarfs other commercial biomass systems in the Americas. One of the bright spots in the future is the Biomass Integrated Gasification/Gas Turbine Electricity Project initially funded in 1992. The sugar cane-based ethanol industry continues to develop higher yielding cane varieties and more efficient microorganisms to convert the sugar cane carbohydrates into alcohol. In Canada a number of important institutions and enterprises taking part in the economical development of the country are involved in biomass research and development including various aspects of the biomass such as forestry, agricultural, industrial, urban, food processing, fisheries and peat bogs. Biomass feedstock research in the United States is evolving to reflect Department of Energy priorities. Greater emphasis is placed on leveraging research with the private sector contributing a greater share of funds, for both research and demonstration projects. The feedstock program, managed by ORNL, is focused on limited model species centered at a regional level using a multidisciplinary approach. Activities include a stronger emphasis on emerging environmental issues such as biodiversity, sustainability and habitat management. DOE also is a supporter of the National Biofuels Roundtable, which is developing principles for producing biomass energy in an economically viable and ecologically sound manner. Geographical Information Systems are also being developed as tools to quantify and characterize the potential supply of energy crops in various regions.