WorldWideScience

Sample records for model simulations capture

  1. Solids Modelling and Capture Simulation of Piperazine in Potassium Solvents

    DEFF Research Database (Denmark)

    Fosbøl, Philip Loldrup; Maribo-Mogensen, Bjørn; Thomsen, Kaj

    2012-01-01

    Piperazine is an amine which is used both as an activator or promoter, but also as active component in CO2 capture solvents. High concentrations are being formulated to draw benefit of the PZ properties. This results in a risk of precipitation of PZ and other solid phases during capture. It could...... be a benefit to the capture process, but it could also result in unforeseen situations of potential hazardous operation, clogging, equipment failure etc.Security of the PZ process needs to be in focus. Flow assurance requires additional attention, especially due to the precipitation phenomenon. This entails...... equilibrium (VLE) calculation, heat capacity determination, and similar thermodynamic properties. It especially allows for determination of solid liquid equilibria (SLE) and heat of absorption/heat of desorption which are core variables in the determination of energy requirements for CO2 capture. In this work...

  2. A Model for Capturing Team Adaptation in Simulated Emergencies

    DEFF Research Database (Denmark)

    Paltved, Charlotte; Musaeus, Peter

    2013-01-01

    Introduction/Background: Acute critical situations and emergencies are among the most challenging situations in medicine where acute care teams are often constituted on an ad hoc basis. In such types of teams, it is obvious that excellent performance depends on the ability of the team to function...... events like closed-loop communication.1 A more nuanced understanding of team communication has the potential to enhance scholarship in interprofessional endeavours. In high risk environments, team performance depends on the ability of teams to quickly alter actions in response to rapidly changing...... and reviewed. The research design used an explorative case study methodology to answer the research question: Which factors most strongly mediate adaptive team performance? Results: Through an iterative, inductive process, data supported the building of the Team Adaptation Tool (TATool) that captures...

  3. Process simulation of CO2 capture with aqueous ammonia using the Extended UNIQUAC model

    DEFF Research Database (Denmark)

    Darde, Victor Camille Alfred; Maribo-Mogensen, Bjørn; van Well, Willy J.M.

    2012-01-01

    The use of aqueous ammonia is a promising option to capture carbon dioxide from power plants thanks to the potential low heat requirement during the carbon dioxide desorption compared to monoethanolamine (MEA) based process. The patented Chilled Ammonia Process developed by Alstom absorbs carbon...... of the process is necessary.In this work, the performance of the carbon dioxide capture process using aqueous ammonia has been analyzed by process simulation. The Extended UNIQUAC thermodynamic model available for the CO2–NH3–H2O system has been implemented in the commercial simulator Aspen Plus®1 by using...... to be in the same range as the values reported recently for advanced amine processes. Assuming that cold cooling water is available, the electricity consumption remains limited. Hence the Chilled Ammonia Process is a promising option for post combustion carbon dioxide capture....

  4. Musculoskeletal Simulation Model Generation from MRI Data Sets and Motion Capture Data

    Science.gov (United States)

    Schmid, Jérôme; Sandholm, Anders; Chung, François; Thalmann, Daniel; Delingette, Hervé; Magnenat-Thalmann, Nadia

    Today computer models and computer simulations of the musculoskeletal system are widely used to study the mechanisms behind human gait and its disorders. The common way of creating musculoskeletal models is to use a generic musculoskeletal model based on data derived from anatomical and biomechanical studies of cadaverous specimens. To adapt this generic model to a specific subject, the usual approach is to scale it. This scaling has been reported to introduce several errors because it does not always account for subject-specific anatomical differences. As a result, a novel semi-automatic workflow is proposed that creates subject-specific musculoskeletal models from magnetic resonance imaging (MRI) data sets and motion capture data. Based on subject-specific medical data and a model-based automatic segmentation approach, an accurate modeling of the anatomy can be produced while avoiding the scaling operation. This anatomical model coupled with motion capture data, joint kinematics information, and muscle-tendon actuators is finally used to create a subject-specific musculoskeletal model.

  5. Monte Carlo simulation of depth dose distribution in several organic models for boron neutron capture therapy

    Science.gov (United States)

    Matsumoto, T.

    2007-09-01

    Monte Carlo simulations are performed to evaluate depth-dose distributions for possible treatment of cancers by boron neutron capture therapy (BNCT). The ICRU computational model of ADAM & EVA was used as a phantom to simulate tumors at a depth of 5 cm in central regions of the lungs, liver and pancreas. Tumors of the prostate and osteosarcoma were also centered at the depth of 4.5 and 2.5 cm in the phantom models. The epithermal neutron beam from a research reactor was the primary neutron source for the MCNP calculation of the depth-dose distributions in those cancer models. For brain tumor irradiations, the whole-body dose was also evaluated. The MCNP simulations suggested that a lethal dose of 50 Gy to the tumors can be achieved without reaching the tolerance dose of 25 Gy to normal tissue. The whole-body phantom calculations also showed that the BNCT could be applied for brain tumors without significant damage to whole-body organs.

  6. CO2 capture in amine solutions: modelling and simulations with non-empirical methods

    Science.gov (United States)

    Andreoni, Wanda; Pietrucci, Fabio

    2016-12-01

    Absorption in aqueous amine solutions is the most advanced technology for the capture of CO2, although suffering from drawbacks that do not allow exploitation on large scale. The search for optimum solvents has been pursued with empirical methods and has also motivated a number of computational approaches over the last decade. However, a deeper level of understanding of the relevant chemical reactions in solution is required so as to contribute to this effort. We present here a brief critical overview of the most recent applications of computer simulations using ab initio methods. Comparison of their outcome shows a strong dependence on the structural models employed to represent the molecular systems in solution and on the strategy used to simulate the reactions. In particular, the results of very recent ab initio molecular dynamics augmented with metadynamics are summarized, showing the crucial role of water, which has been so far strongly underestimated both in the calculations and in the interpretation of experimental data. Indications are given for advances in computational approaches that are necessary if meant to contribute to the rational design of new solvents.

  7. CO2 capture in amine solutions: modelling and simulations with non-empirical methods.

    Science.gov (United States)

    Andreoni, Wanda; Pietrucci, Fabio

    2016-12-21

    Absorption in aqueous amine solutions is the most advanced technology for the capture of CO2, although suffering from drawbacks that do not allow exploitation on large scale. The search for optimum solvents has been pursued with empirical methods and has also motivated a number of computational approaches over the last decade. However, a deeper level of understanding of the relevant chemical reactions in solution is required so as to contribute to this effort. We present here a brief critical overview of the most recent applications of computer simulations using ab initio methods. Comparison of their outcome shows a strong dependence on the structural models employed to represent the molecular systems in solution and on the strategy used to simulate the reactions. In particular, the results of very recent ab initio molecular dynamics augmented with metadynamics are summarized, showing the crucial role of water, which has been so far strongly underestimated both in the calculations and in the interpretation of experimental data. Indications are given for advances in computational approaches that are necessary if meant to contribute to the rational design of new solvents.

  8. Disability weight of Clonorchis sinensis infection: captured from community study and model simulation.

    Directory of Open Access Journals (Sweden)

    Men-Bao Qian

    2011-12-01

    Full Text Available BACKGROUND: Clonorchiasis is among the most neglected tropical diseases. It is caused by ingesting raw or undercooked fish or shrimp containing the larval of Clonorchis sinensis and mainly endemic in Southeast Asia including China, Korea and Vietnam. The global estimations for population at risk and infected are 601 million and 35 million, respectively. However, it is still not listed among the Global Burden of Disease (GBD and no disability weight is available for it. Disability weight reflects the average degree of loss of life value due to certain chronic disease condition and ranges between 0 (complete health and 1 (death. It is crucial parameter for calculating the morbidity part of any disease burden in terms of disability-adjusted life years (DALYs. METHODOLOGY/PRINCIPAL FINDINGS: According to the probability and disability weight of single sequelae caused by C. sinensis infection, the overall disability weight could be captured through Monte Carlo simulation. The probability of single sequelae was gained from one community investigation, while the corresponding disability weight was searched from the literatures in evidence-based approach. The overall disability weights of the male and female were 0.101 and 0.050, respectively. The overall disability weights of the age group of 5-14, 15-29, 30-44, 45-59 and 60+ were 0.022, 0.052, 0.072, 0.094 and 0.118, respectively. There was some evidence showing that the disability weight and geometric mean of eggs per gram of feces (GMEPG fitted a logarithmic equation. CONCLUSION/SIGNIFICANCE: The overall disability weights of C. sinensis infection are differential in different sex and age groups. The disability weight captured here may be referred for estimating the disease burden of C. sinensis infection.

  9. Capturing flood-to-drought transitions in regional climate model simulations

    Science.gov (United States)

    Anders, Ivonne; Haslinger, Klaus; Hofstätter, Michael; Salzmann, Manuela; Resch, Gernot

    2017-04-01

    In previous studies atmospheric cyclones have been investigated in terms of related precipitation extremes in Central Europe. Mediterranean (Vb-like) cyclones are of special relevance as they are frequently related to high atmospheric moisture fluxes leading to floods and landslides in the Alpine region. Another focus in this area is on droughts, affecting soil moisture and surface and sub-surface runoff as well. Such events develop differently depending on available pre-saturation of water in the soil. In a first step we investigated two time periods which encompass a flood event and a subsequent drought on very different time scales, one long lasting transition (2002/2003) and a rather short one between May and August 2013. In a second step we extended the investigation to the long time period 1950-2016. We focused on high spatial and temporal scales and assessed the currently achievable accuracy in the simulation of the Vb-events on one hand and following drought events on the other hand. The state-of-the-art regional climate model CCLM is applied in hindcast-mode simulating the single events described above, but also the time from 1948 to 2016 to evaluate the results from the short runs to be valid for the long time period. Besides the conventional forcing of the regional climate model at its lateral boundaries, a spectral nudging technique is applied. The simulations covering the European domain have been varied systematically different model parameters. The resulting precipitation amounts have been compared to E-OBS gridded European precipitation data set and a recent high spatially resolved precipitation data set for Austria (GPARD-6). For the drought events the Standardized Precipitation Evapotranspiration Index (SPEI), soil moisture and runoff has been investigated. Varying the spectral nudging setup helps us to understand the 3D-processes during these events, but also to identify model deficiencies. To improve the simulation of such events in the past

  10. Monte Carlo simulation of depth-dose distribution in several organic models for boron neutron capture therapy

    Energy Technology Data Exchange (ETDEWEB)

    Matsumoto, T. [Atomic Energy Research Laboratory, Musashi Institute of Technology, 971 Ozenji, Asao-ku, Kawasaki-shi 215 0013 (Japan)], E-mail: mtetsuo@atom.musashi-tech.ac.jp

    2007-09-21

    Monte Carlo simulations are performed to evaluate depth-dose distributions for possible treatment of cancers by boron neutron capture therapy (BNCT). The ICRU computational model of ADAM and EVA was used as a phantom to simulate tumors at a depth of 5 cm in central regions of the lungs, liver and pancreas. Tumors of the prostate and osteosarcoma were also centered at the depth of 4.5 and 2.5 cm in the phantom models. The epithermal neutron beam from a research reactor was the primary neutron source for the MCNP calculation of the depth-dose distributions in those cancer models. For brain tumor irradiations, the whole-body dose was also evaluated. The MCNP simulations suggested that a lethal dose of 50 Gy to the tumors can be achieved without reaching the tolerance dose of 25 Gy to normal tissue. The whole-body phantom calculations also showed that the BNCT could be applied for brain tumors without significant damage to whole-body organs.

  11. Molecular simulation studies of CO2 adsorption by carbon model compounds for carbon capture and sequestration applications.

    Science.gov (United States)

    Liu, Yangyang; Wilcox, Jennifer

    2013-01-02

    Effects of oxygen-containing surface functionalities on the adsorption of mixtures including CO(2)/CH(4), CO(2)/N(2), and CO(2)/H(2)O have been investigated in the current work. Together with Bader charge analysis, electronic structure calculations have provided the initial framework comprising both the geometry and corresponding charge information required to carry out statistical-based molecular simulations. The adsorption isotherms and selectivity of CO(2) from CO(2)/N(2), CO(2)/CH(4), and CO(2)/H(2)O gas mixtures were determined by grand canonical Monte Carlo simulations at temperature/pressure conditions relevant to carbon capture and sequestration applications. The interactions between the surfaces with induced polarity and nonpolar/polar molecules have been investigated. It has been observed that, due to the induced polarity of the surface functionalization, the selectivity of CO(2) over CH(4) increases from approximately 2 to higher than 5, and the selectivity of CO(2) over N(2) increases from approximately 5 to 20, especially in the low-pressure regime. However, water vapor will always preferentially adsorb over CO(2) in carbon-based systems containing oxygen functionalized surfaces at conditions relevant to carbon capture application. Molecular simulation results indicate that the surface chemistry in micropores is tunable thereby influencing the selectivity for enhanced uptake of CO(2).

  12. Simulation Modeling to Interpret the Captures of Moths in Pheromone-Baited Traps Used for Surveillance of Invasive Species: the Gypsy Moth as a Model Case.

    Science.gov (United States)

    Bau, Josep; Cardé, Ring T

    2016-09-01

    When pheromone traps are used for detection of an invasive pest and then delimitation of its distribution, an unresolved issue is the interpretation of failure to capture any target insects. Is a population present but not detected, a so-called false negative? Using the gypsy moth (Lymantria dispar) as an exemplar, we modeled the probability of males being captured in traps deployed at densities typical for surveillance (1 per 2.6 km(2) or 1 per mi(2)) and delimitation (up to 49 per 2.6 km(2)). The simulations used a dynamic wind model generating a turbulent plume structure and varying wind direction, and a behavior model based on the documented maneuvers of gypsy moths during plume acquisition and along-plume navigation. Several strategies of plume acquisition using Correlated Random Walks were compared to ensure that the generated dispersions over three days were not either overly clumped or ranged many km. Virtual moths were released into virtual space with patterns mimicking prior releases of gypsy moth males in Massachusetts at varying distance from a baited trap. In general, capture rates of virtual and real moths at varying trap densities were similar. One application of this approach was to estimate through bootstrapping the probabilities of not detecting populations having densities ranging from 1 to 100 moths per 2.6 km(2) and using traps that varied from 25 to 100 % in their efficiencies of capture. Low-level populations (e.g., 20-30 per 2.6 km(2)) often were not detected with one trap per 2.6 km(2), especially when traps had low efficiencies.

  13. PIMMS tools for capturing metadata about simulations

    Science.gov (United States)

    Pascoe, Charlotte; Devine, Gerard; Tourte, Gregory; Pascoe, Stephen; Lawrence, Bryan; Barjat, Hannah

    2013-04-01

    PIMMS (Portable Infrastructure for the Metafor Metadata System) provides a method for consistent and comprehensive documentation of modelling activities that enables the sharing of simulation data and model configuration information. The aim of PIMMS is to package the metadata infrastructure developed by Metafor for CMIP5 so that it can be used by climate modelling groups in UK Universities. PIMMS tools capture information about simulations from the design of experiments to the implementation of experiments via simulations that run models. PIMMS uses the Metafor methodology which consists of a Common Information Model (CIM), Controlled Vocabularies (CV) and software tools. PIMMS software tools provide for the creation and consumption of CIM content via a web services infrastructure and portal developed by the ES-DOC community. PIMMS metadata integrates with the ESGF data infrastructure via the mapping of vocabularies onto ESGF facets. There are three paradigms of PIMMS metadata collection: Model Intercomparision Projects (MIPs) where a standard set of questions is asked of all models which perform standard sets of experiments. Disciplinary level metadata collection where a standard set of questions is asked of all models but experiments are specified by users. Bespoke metadata creation where the users define questions about both models and experiments. Examples will be shown of how PIMMS has been configured to suit each of these three paradigms. In each case PIMMS allows users to provide additional metadata beyond that which is asked for in an initial deployment. The primary target for PIMMS is the UK climate modelling community where it is common practice to reuse model configurations from other researchers. This culture of collaboration exists in part because climate models are very complex with many variables that can be modified. Therefore it has become common practice to begin a series of experiments by using another climate model configuration as a starting

  14. Longitudinal RF capture simulation and BPM signal estimation

    CERN Document Server

    Feng, Yong-Chun; Chen, Yu-Cong; Yin, Yan; Zhang, Xiao-Hu; Ruan, Shuang; Liu, Tong; You, Yao-Yao; Kang, Xin-Cai; Zhao, Tie-Cheng; Xu, Zhi-Guo; Li, Peng; Wang, Yan-Yu; Yuan, You-Jin

    2016-01-01

    In this paper, the theoretical aspects behind longitudinal RF capture are reviewed and the capture process is simulated via a program based on this theory. Four kinds of cases with different initial distribution and capture curve are considered, i.e. uniform distribution with adiabatic capture, uniform distribution with non-adiabatic capture, Gaussian distribution with adiabatic capture and Gaussian distribution with non-adiabatic capture. The simulation results are compared each other and discussed, and Gaussian distribution with adiabatic capture is demonstrated having a higher capture efficiency and leading to a shorter bunch length. In addition, the BPM induced signal is simulated with high input impendence, i.e. $1M\\Omega$, and low input impendence, i.e. $50\\Omega$, respectively. Finally, the BPM signal of Heavy Ion Medical Machine (HIMM) is estimated and compared with measured one, and a good agreement is achieved.

  15. Annual Report: Carbon Capture Simulation Initiative (CCSI) (30 September 2012)

    Energy Technology Data Exchange (ETDEWEB)

    Miller, David C. [National Energy Technology Lab. (NETL), Morgantown, WV (United States); Syamlal, Madhava [National Energy Technology Lab. (NETL), Morgantown, WV (United States); Cottrell, Roger [URS Corporation. (URS), San Francisco, CA (United States); National Energy Technology Lab. (NETL), Morgantown, WV (United States); Kress, Joel D. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Sun, Xin [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Sundaresan, S. [Princeton Univ., NJ (United States); Sahinidis, Nikolaos V. [Carnegie Mellon Univ., Pittsburgh, PA (United States); National Energy Technology Lab. (NETL), Morgantown, WV (United States); Zitney, Stephen E. [NETL; Bhattacharyya, D. [West Virginia Univ., Morgantown, WV (United States); National Energy Technology Lab. (NETL), Morgantown, WV (United States); Agarwal, Deb [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Tong, Charles [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Lin, Guang [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Dale, Crystal [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Engel, Dave [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Calafiura, Paolo [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Beattie, Keith [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Shinn, John [SynPatEco. Pleasant Hill, CA (United States)

    2012-09-30

    The Carbon Capture Simulation Initiative (CCSI) is a partnership among national laboratories, industry and academic institutions that is developing and deploying state-of-the-art computational modeling and simulation tools to accelerate the commercialization of carbon capture technologies from discovery to development, demonstration, and ultimately the widespread deployment to hundreds of power plants. The CCSI Toolset will provide end users in industry with a comprehensive, integrated suite of scientifically validated models, with uncertainty quantification (UQ), optimization, risk analysis and decision making capabilities. The CCSI Toolset incorporates commercial and open-source software currently in use by industry and is also developing new software tools as necessary to fill technology gaps identified during execution of the project. Ultimately, the CCSI Toolset will (1) enable promising concepts to be more quickly identified through rapid computational screening of devices and processes; (2) reduce the time to design and troubleshoot new devices and processes; (3) quantify the technical risk in taking technology from laboratory-scale to commercial-scale; and (4) stabilize deployment costs more quickly by replacing some of the physical operational tests with virtual power plant simulations. CCSI is organized into 8 technical elements that fall under two focus areas. The first focus area (Physicochemical Models and Data) addresses the steps necessary to model and simulate the various technologies and processes needed to bring a new Carbon Capture and Storage (CCS) technology into production. The second focus area (Analysis & Software) is developing the software infrastructure to integrate the various components and implement the tools that are needed to make quantifiable decisions regarding the viability of new CCS technologies. CCSI also has an Industry Advisory Board (IAB). By working closely with industry from the inception of the project to identify

  16. Annual Report: Carbon Capture Simulation Initiative (CCSI) (30 September 2012)

    Energy Technology Data Exchange (ETDEWEB)

    Miller, David C. [National Energy Technology Lab. (NETL), Morgantown, WV (United States); Syamlal, Madhava [National Energy Technology Lab. (NETL), Morgantown, WV (United States); Cottrell, Roger [URS Corporation. (URS), San Francisco, CA (United States); National Energy Technology Lab. (NETL), Morgantown, WV (United States); Kress, Joel D. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Sun, Xin [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Sundaresan, S. [Princeton Univ., NJ (United States); Sahinidis, Nikolaos V. [Carnegie Mellon Univ., Pittsburgh, PA (United States); National Energy Technology Lab. (NETL), Morgantown, WV (United States); Zitney, Stephen E. [NETL; Bhattacharyya, D. [West Virginia Univ., Morgantown, WV (United States); National Energy Technology Lab. (NETL), Morgantown, WV (United States); Agarwal, Deb [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Tong, Charles [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Lin, Guang [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Dale, Crystal [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Engel, Dave [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Calafiura, Paolo [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Beattie, Keith [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Shinn, John [SynPatEco. Pleasant Hill, CA (United States)

    2012-09-30

    The Carbon Capture Simulation Initiative (CCSI) is a partnership among national laboratories, industry and academic institutions that is developing and deploying state-of-the-art computational modeling and simulation tools to accelerate the commercialization of carbon capture technologies from discovery to development, demonstration, and ultimately the widespread deployment to hundreds of power plants. The CCSI Toolset will provide end users in industry with a comprehensive, integrated suite of scientifically validated models, with uncertainty quantification (UQ), optimization, risk analysis and decision making capabilities. The CCSI Toolset incorporates commercial and open-source software currently in use by industry and is also developing new software tools as necessary to fill technology gaps identified during execution of the project. Ultimately, the CCSI Toolset will (1) enable promising concepts to be more quickly identified through rapid computational screening of devices and processes; (2) reduce the time to design and troubleshoot new devices and processes; (3) quantify the technical risk in taking technology from laboratory-scale to commercial-scale; and (4) stabilize deployment costs more quickly by replacing some of the physical operational tests with virtual power plant simulations. CCSI is organized into 8 technical elements that fall under two focus areas. The first focus area (Physicochemical Models and Data) addresses the steps necessary to model and simulate the various technologies and processes needed to bring a new Carbon Capture and Storage (CCS) technology into production. The second focus area (Analysis & Software) is developing the software infrastructure to integrate the various components and implement the tools that are needed to make quantifiable decisions regarding the viability of new CCS technologies. CCSI also has an Industry Advisory Board (IAB). By working closely with industry from the inception of the project to identify

  17. Annual Report: Carbon Capture Simulation Initiative (CCSI) (30 September 2013)

    Energy Technology Data Exchange (ETDEWEB)

    Miller, David C. [National Energy Technology Lab. (NETL), Morgantown, WV (United States); Syamlal, Madhava [National Energy Technology Lab. (NETL), Morgantown, WV (United States); Cottrell, Roger [URS Corporation. (URS), San Francisco, CA (United States); National Energy Technology Lab. (NETL), Morgantown, WV (United States); Kress, Joel D. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Sundaresan, S. [Princeton Univ., NJ (United States); Sun, Xin [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Storlie, C. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Bhattacharyya, D. [West Virginia Univ., Morgantown, WV (United States); National Energy Technology Lab. (NETL), Morgantown, WV (United States); Tong, Charles [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Zitney, Stephen E [National Energy Technology Lab. (NETL), Morgantown, WV (United States); Dale, Crystal [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Engel, Dave [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Agarwal, Deb [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Calafiura, Paolo [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Shinn, John [SynPatEco, Pleasant Hill, CA (United States)

    2014-03-05

    The Carbon Capture Simulation Initiative (CCSI) is a partnership among national laboratories, industry and academic institutions that is developing and deploying state-of-the-art computational modeling and simulation tools to accelerate the commercialization of carbon capture technologies from discovery to development, demonstration, and ultimately the widespread deployment to hundreds of power plants. The CCSI Toolset will provide end users in industry with a comprehensive, integrated suite of scientifically validated models, with uncertainty quantification (UQ), optimization, risk analysis and decision making capabilities. The CCSI Toolset incorporates commercial and open-source software currently in use by industry and is also developing new software tools as necessary to fill technology gaps identified during execution of the project. Ultimately, the CCSI Toolset will (1) enable promising concepts to be more quickly identified through rapid computational screening of devices and processes; (2) reduce the time to design and troubleshoot new devices and processes; (3) quantify the technical risk in taking technology from laboratory-scale to commercial-scale; and (4) stabilize deployment costs more quickly by replacing some of the physical operational tests with virtual power plant simulations. CCSI is led by the National Energy Technology Laboratory (NETL) and leverages the Department of Energy (DOE) national laboratories’ core strengths in modeling and simulation, bringing together the best capabilities at NETL, Los Alamos National Laboratory (LANL), Lawrence Berkeley National Laboratory (LBNL), Lawrence Livermore National Laboratory (LLNL), and Pacific Northwest National Laboratory (PNNL). The CCSI’s industrial partners provide representation from the power generation industry, equipment manufacturers, technology providers and engineering and construction firms. The CCSI’s academic participants (Carnegie Mellon University, Princeton University, West

  18. Simulations of electron capture supernovae with approximate neutrino transport

    Energy Technology Data Exchange (ETDEWEB)

    Moeller, Heiko [TU Darmstadt (Germany); Fischer, Tobias [University of Wroclaw (Poland); Jones, Sam [Keele University (United Kingdom); Martinez-Pinedo, Gabriel [TU Darmstadt (Germany); GSI Helmholtzzentrum fuer Schwerionenforschung, Darmstadt (Germany)

    2014-07-01

    We have performed simulations of electron capture supernovae in a spherically symmetric general relativistic radiation hydrodynamics model with approximate neutrino treatment. We base our study on an 8.8 M {sub CircleDot} O-Ne-Mg core progenitor (Nomoto, 1984, 1987). We successfully obtain an explosion and compare our results with a reference run performed with an state-of-the-art three-flavor Boltzmann neutrino transport scheme implemented into the same hydrodynamic code. In general, we find good agreement in the the electron-flavor neutrino spectra. However, we find shorter explosion timescales and also significantly lower explosion energies of only 1.4 . 10{sup 48} erg. This result is in agreement with the explosion energy of SN 2008S as derived by Tominaga et al. (2013) based on light curve studies. Currently we are extending our simulations to the recently published super-AGB star progenitor models by Jones et al. (2013) with regard to their evolution towards an electron capture supernova. Our study also explores the role of weak interaction rates in determining the evolution and shaping the spectra of the emitted neutrinos.

  19. Annual Report: Carbon Capture Simulation Initiative (CCSI) (30 September 2013)

    Energy Technology Data Exchange (ETDEWEB)

    Miller, David C. [National Energy Technology Lab. (NETL), Morgantown, WV (United States); Syamlal, Madhava [National Energy Technology Lab. (NETL), Morgantown, WV (United States); Cottrell, Roger [URS Corporation. (URS), San Francisco, CA (United States); National Energy Technology Lab. (NETL), Morgantown, WV (United States); Kress, Joel D. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Sundaresan, S. [Princeton Univ., NJ (United States); Sun, Xin [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Storlie, C. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Bhattacharyya, D. [West Virginia Univ., Morgantown, WV (United States); National Energy Technology Lab. (NETL), Morgantown, WV (United States); Tong, Charles [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Zitney, Stephen E [National Energy Technology Lab. (NETL), Morgantown, WV (United States); Dale, Crystal [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Engel, Dave [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Agarwal, Deb [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Calafiura, Paolo [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Shinn, John [SynPatEco, Pleasant Hill, CA (United States)

    2014-03-05

    The Carbon Capture Simulation Initiative (CCSI) is a partnership among national laboratories, industry and academic institutions that is developing and deploying state-of-the-art computational modeling and simulation tools to accelerate the commercialization of carbon capture technologies from discovery to development, demonstration, and ultimately the widespread deployment to hundreds of power plants. The CCSI Toolset will provide end users in industry with a comprehensive, integrated suite of scientifically validated models, with uncertainty quantification (UQ), optimization, risk analysis and decision making capabilities. The CCSI Toolset incorporates commercial and open-source software currently in use by industry and is also developing new software tools as necessary to fill technology gaps identified during execution of the project. Ultimately, the CCSI Toolset will (1) enable promising concepts to be more quickly identified through rapid computational screening of devices and processes; (2) reduce the time to design and troubleshoot new devices and processes; (3) quantify the technical risk in taking technology from laboratory-scale to commercial-scale; and (4) stabilize deployment costs more quickly by replacing some of the physical operational tests with virtual power plant simulations. CCSI is led by the National Energy Technology Laboratory (NETL) and leverages the Department of Energy (DOE) national laboratories’ core strengths in modeling and simulation, bringing together the best capabilities at NETL, Los Alamos National Laboratory (LANL), Lawrence Berkeley National Laboratory (LBNL), Lawrence Livermore National Laboratory (LLNL), and Pacific Northwest National Laboratory (PNNL). The CCSI’s industrial partners provide representation from the power generation industry, equipment manufacturers, technology providers and engineering and construction firms. The CCSI’s academic participants (Carnegie Mellon University, Princeton University, West

  20. CO2 capture using aqueous ammonia: kinetic study and process simulation

    DEFF Research Database (Denmark)

    Darde, Victor Camille Alfred; van Well, Willy J.M.; Stenby, Erling Halfdan

    2011-01-01

    Carbon dioxide capture using aqueous ammonia is a post-combustion technology that has shown a good potential. Therefore this process is studied by measuring the rate of absorption of carbon dioxide by aqueous ammonia and by performing process simulation. The rate of absorption of carbon dioxide...... to 0.6. The results were compared with those found for 30 wt% mono-ethanolamine (MEA) solutions.The capture process was simulated successfully using the simulator Aspen Plus coupled with the extended UNIQUAC thermodynamic model available for the NH3–CO2–H2O system. For this purpose, a user model...

  1. Process Simulation of Oxy-combustion CO2 Capture in Cement Plant

    OpenAIRE

    2014-01-01

    The objectives of this master thesis have been to model and simulate oxy-combustion CO2 capture in a cement plant. The model developed is a process simulation of the calcination process with varying degree of air in-leakage, where heat is supplied by combustion in an oxygen rich environment, followed by capture of the CO2. The further gas separation after H2O condensation to achieve the required CO2 quality was evaluated. In addition to the process simulations, a review of literature related ...

  2. Construction of a novel coarse grain model for simulations of HIV capsid assembly to capture the backbone structure and inter-domain motions in solution

    Directory of Open Access Journals (Sweden)

    Xin Qiao

    2015-12-01

    Full Text Available We show the construction of a novel coarse grain model for simulations of HIV capsid assembly based on four structural models of HIV capsid proteins: isolated hexamer 3H47.pdb, tubular assembly 3J34.pdb, isolated pentamer 3P05.pdb and C-terminus dimer 2KOD.pdb. The data demonstrates the derivation of inter-domain motions from all atom Molecular Dynamics simulations and comparison with the motions derived from the analysis of solution NMR results defined in 2M8L.pdb. Snapshots from a representative Monte Carlo simulation with 128 dimeric subunit proteins based on 3J34.pdb are shown in addition to the quantitative analysis of its assembly pathway. Movies of the assembly process are compiled with snapshots of representative simulations of four structural models. The methods and data in this article were utilized in Qiao et al. (in press [1] to probe the mechanism of polymorphism and curvature control of HIV capsid assembly.

  3. Cloth Simulation Based Motion Capture of Dressed Humans

    Science.gov (United States)

    Hasler, Nils; Rosenhahn, Bodo; Seidel, Hans-Peter

    Commonly, marker based as well as markerless motion capture systems assume that the tracked person is wearing tightly fitting clothes. Unfortunately, this restriction cannot be satisfied in many situations and most preexisting video data does not adhere to it either. In this work we propose a graphics based vision approach for tracking humans markerlessly without making this assumption. Instead, a physically based simulation of the clothing the tracked person is wearing is used to guide the tracking algorithm.

  4. Optimising the application of multiple-capture traps for invasive species management using spatial simulation.

    Science.gov (United States)

    Warburton, Bruce; Gormley, Andrew M

    2015-01-01

    Internationally, invasive vertebrate species pose a significant threat to biodiversity, agricultural production and human health. To manage these species a wide range of tools, including traps, are used. In New Zealand, brushtail possums (Trichosurus vulpecula), stoats (Mustela ermine), and ship rats (Rattus rattus) are invasive and there is an ongoing demand for cost-effective non-toxic methods for controlling these pests. Recently, traps with multiple-capture capability have been developed which, because they do not require regular operator-checking, are purported to be more cost-effective than traditional single-capture traps. However, when pest populations are being maintained at low densities (as is typical of orchestrated pest management programmes) it remains uncertain if it is more cost-effective to use fewer multiple-capture traps or more single-capture traps. To address this uncertainty, we used an individual-based spatially explicit modelling approach to determine the likely maximum animal-captures per trap, given stated pest densities and defined times traps are left between checks. In the simulation, single- or multiple-capture traps were spaced according to best practice pest-control guidelines. For possums with maintenance densities set at the lowest level (i.e. 0.5/ha), 98% of all simulated possums were captured with only a single capacity trap set at each site. When possum density was increased to moderate levels of 3/ha, having a capacity of three captures per trap caught 97% of all simulated possums. Results were similar for stoats, although only two potential captures per site were sufficient to capture 99% of simulated stoats. For rats, which were simulated at their typically higher densities, even a six-capture capacity per trap site only resulted in 80% kill. Depending on target species, prevailing density and extent of immigration, the most cost-effective strategy for pest control in New Zealand might be to deploy several single-capture

  5. Optimising the application of multiple-capture traps for invasive species management using spatial simulation.

    Directory of Open Access Journals (Sweden)

    Bruce Warburton

    Full Text Available Internationally, invasive vertebrate species pose a significant threat to biodiversity, agricultural production and human health. To manage these species a wide range of tools, including traps, are used. In New Zealand, brushtail possums (Trichosurus vulpecula, stoats (Mustela ermine, and ship rats (Rattus rattus are invasive and there is an ongoing demand for cost-effective non-toxic methods for controlling these pests. Recently, traps with multiple-capture capability have been developed which, because they do not require regular operator-checking, are purported to be more cost-effective than traditional single-capture traps. However, when pest populations are being maintained at low densities (as is typical of orchestrated pest management programmes it remains uncertain if it is more cost-effective to use fewer multiple-capture traps or more single-capture traps. To address this uncertainty, we used an individual-based spatially explicit modelling approach to determine the likely maximum animal-captures per trap, given stated pest densities and defined times traps are left between checks. In the simulation, single- or multiple-capture traps were spaced according to best practice pest-control guidelines. For possums with maintenance densities set at the lowest level (i.e. 0.5/ha, 98% of all simulated possums were captured with only a single capacity trap set at each site. When possum density was increased to moderate levels of 3/ha, having a capacity of three captures per trap caught 97% of all simulated possums. Results were similar for stoats, although only two potential captures per site were sufficient to capture 99% of simulated stoats. For rats, which were simulated at their typically higher densities, even a six-capture capacity per trap site only resulted in 80% kill. Depending on target species, prevailing density and extent of immigration, the most cost-effective strategy for pest control in New Zealand might be to deploy several

  6. A new pilot absorber for CO2 capture from flue gases: Measuring and modelling capture with MEA solution

    DEFF Research Database (Denmark)

    Sønderby, Tim L.; Carlsen, Kim B.; Fosbøl, Philip Loldrup

    2013-01-01

    A pilot absorber column for CO2 recovery from flue gases was constructed and tested with aqueous 30wt% monoethanolamine (MEA), a primary amine, as capture solvent. The pilot plant data were compared with a mathematical rate based packed-column model. The simulation results compared well with the ......A pilot absorber column for CO2 recovery from flue gases was constructed and tested with aqueous 30wt% monoethanolamine (MEA), a primary amine, as capture solvent. The pilot plant data were compared with a mathematical rate based packed-column model. The simulation results compared well...

  7. Validation of simulation models

    DEFF Research Database (Denmark)

    Rehman, Muniza; Pedersen, Stig Andur

    2012-01-01

    In philosophy of science, the interest for computational models and simulations has increased heavily during the past decades. Different positions regarding the validity of models have emerged but the views have not succeeded in capturing the diversity of validation methods. The wide variety...... of models has been somewhat narrow-minded reducing the notion of validation to establishment of truth. This article puts forward the diversity in applications of simulation models that demands a corresponding diversity in the notion of validation....... of models with regards to their purpose, character, field of application and time dimension inherently calls for a similar diversity in validation approaches. A classification of models in terms of the mentioned elements is presented and used to shed light on possible types of validation leading...

  8. Simulation and Comparative Study of CO2 Capture in Underwater LSS Using HYSYS

    Institute of Scientific and Technical Information of China (English)

    HUANG Zhi-guang; WANG Rong-shun; GU An-zhong

    2007-01-01

    Long-duration manned submersible missions require advanced life support systems (LSS) that can regenerate air, water and food. This study presented two CO2-capture methods used in LSS, CO2 removal with diethanolamine (DEA) and cryo-freezing with liquid oxygen. Both processes were modeled and simulated with HYSYS simulator. The performance of the two types of module was compared, and the results showed that the latter could be advantageous over the former in specific power, facility scale, operation reliability and safety. Economic evaluation suggested the latter cost only half of the former. Cryo-capture module could be an alternative for underwater LSS because of its efficiency and compactness.

  9. Use of population pharmacokinetic modeling and Monte Carlo simulation to capture individual animal variability in the prediction of flunixin withdrawal times in cattle.

    Science.gov (United States)

    Wu, H; Baynes, R E; Leavens, T; Tell, L A; Riviere, J E

    2013-06-01

    The objective of this study was to develop a population pharmacokinetic (PK) model and predict tissue residues and the withdrawal interval (WDI) of flunixin in cattle. Data were pooled from published PK studies in which flunixin was administered through various dosage regimens to diverse populations of cattle. A set of liver data used to establish the regulatory label withdrawal time (WDT) also were used in this study. Compartmental models with first-order absorption and elimination were fitted to plasma and liver concentrations by a population PK modeling approach. Monte Carlo simulations were performed with the population mean and variabilities of PK parameters to predict liver concentrations of flunixin. The PK of flunixin was described best by a 3-compartment model with an extra liver compartment. The WDI estimated in this study with liver data only was the same as the label WDT. However, a longer WDI was estimated when both plasma and liver data were included in the population PK model. This study questions the use of small groups of healthy animals to determine WDTs for drugs intended for administration to large diverse populations. This may warrant a reevaluation of the current procedure for establishing WDT to prevent violative residues of flunixin.

  10. Analysis of Reaction-Diffusion Systems for Flame Capturing in Type Ia Supernova Simulations

    CERN Document Server

    Zhiglo, Andrey V

    2009-01-01

    We present a study of numerical behavior of a thickened flame used in Flame Capturing (FC, Khokhlov (1995)) for tracking thin unresolved physical flames in deflagration simulations. We develop a steady-state procedure for calibrating the flame model used, and test it against analytical results. We observe numerical noises generated by original realization of the technique. Alternative artificial burning rates are discussed, which produce acceptably quiet flames. Two new quiet models are calibrated to yield required "flame" speed and width, and further studied in 2D and 3D setting. Landau-Darrieus type instabilities of the flames are observed. One model also shows significantly anisotropic propagation speed on the grid, both effects increasingly pronounced at larger matter expansion as a result of burning; this makes the model unacceptable for use in type Ia supernova simulations. Another model looks promising for use in flame capturing at fuel to ash density ratio of order 3 and below. That "Model B" yields f...

  11. Modeling and assessment of future IGCC plant concepts with CO{sub 2} capture; Simulation und Bewertung zukuenftiger IGCC-Kraftwerkskonzepte mit CO{sub 2}-Abtrennung

    Energy Technology Data Exchange (ETDEWEB)

    Kunze, Christian A.

    2012-07-13

    The thesis focuses on the assessment of efficiency potential of future IGCC plants with CO{sub 2} capture. Starting point is a comprehensive analysis (thermodynamic, economic and exergy) of a state of the art IGCC. Additionally, five future IGCC concepts are proposed and evaluated for their efficiency potential in the mid- and long-term. The concepts showed significantly higher efficiencies up to approximately 60% and enable an almost CO{sub 2}-free operation.

  12. A dynamic mathematical model for packed columns in carbon capture plants

    DEFF Research Database (Denmark)

    Gaspar, Jozsef; Jørgensen, John Bagterp; Fosbøl, Philip Loldrup

    2015-01-01

    In this paper, we present a dynamic mathematical model for the absorption and desorption columns in a carbon capture plant. Carbon capture plants must be operated in synchronization with the operation of thermal power plants. Dynamic and flexible operation of the carbon capture plant is important...... simulation using monoethanolamine (MEA) and piperazine (PZ) as solvent. MEA is considered as the base-case solvent in the carbon capture business. The effect of changes in the flue gas flow rate and changes in the available steam are investigated to determine their influence on the performance of the capture...... process. The response of the model is shown in terms of capture efficiency and purity of the CO2 product stream. The model is aimed for rigorous dynamic simulation in the context of optimization and control strategy development....

  13. Multi-scale modeling of carbon capture systems

    Energy Technology Data Exchange (ETDEWEB)

    Kress, Joel David [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

    2017-03-03

    The development and scale up of cost effective carbon capture processes is of paramount importance to enable the widespread deployment of these technologies to significantly reduce greenhouse gas emissions. The U.S. Department of Energy initiated the Carbon Capture Simulation Initiative (CCSI) in 2011 with the goal of developing a computational toolset that would enable industry to more effectively identify, design, scale up, operate, and optimize promising concepts. The first half of the presentation will introduce the CCSI Toolset consisting of basic data submodels, steady-state and dynamic process models, process optimization and uncertainty quantification tools, an advanced dynamic process control framework, and high-resolution filtered computationalfluid- dynamics (CFD) submodels. The second half of the presentation will describe a high-fidelity model of a mesoporous silica supported, polyethylenimine (PEI)-impregnated solid sorbent for CO2 capture. The sorbent model includes a detailed treatment of transport and amine-CO2- H2O interactions based on quantum chemistry calculations. Using a Bayesian approach for uncertainty quantification, we calibrate the sorbent model to Thermogravimetric (TGA) data.

  14. Evaluation of bias associated with capture maps derived from nonlinear groundwater flow models

    Science.gov (United States)

    Nadler, Cara; Allander, Kip K.; Pohll, Greg; Morway, Eric; Naranjo, Ramon C.; Huntington, Justin

    2017-01-01

    The impact of groundwater withdrawal on surface water is a concern of water users and water managers, particularly in the arid western United States. Capture maps are useful tools to spatially assess the impact of groundwater pumping on water sources (e.g., streamflow depletion) and are being used more frequently for conjunctive management of surface water and groundwater. Capture maps have been derived using linear groundwater flow models and rely on the principle of superposition to demonstrate the effects of pumping in various locations on resources of interest. However, nonlinear models are often necessary to simulate head-dependent boundary conditions and unconfined aquifers. Capture maps developed using nonlinear models with the principle of superposition may over- or underestimate capture magnitude and spatial extent. This paper presents new methods for generating capture difference maps, which assess spatial effects of model nonlinearity on capture fraction sensitivity to pumping rate, and for calculating the bias associated with capture maps. The sensitivity of capture map bias to selected parameters related to model design and conceptualization for the arid western United States is explored. This study finds that the simulation of stream continuity, pumping rates, stream incision, well proximity to capture sources, aquifer hydraulic conductivity, and groundwater evapotranspiration extinction depth substantially affect capture map bias. Capture difference maps demonstrate that regions with large capture fraction differences are indicative of greater potential capture map bias. Understanding both spatial and temporal bias in capture maps derived from nonlinear groundwater flow models improves their utility and defensibility as conjunctive-use management tools.

  15. Longitudinal RF capture and acceleration simulation in CSNS RCS

    Institute of Scientific and Technical Information of China (English)

    LIU Lin; TANG Jing-Yu; QIU Jing; WEI Tao

    2009-01-01

    China Spallation Neutron Source(CSNS)is a high power proton accelerator-based facility.Uncontrolled beam loss is a major concern in designing the CSNS to control the radioactivation level.For the Rapid Cycling Synchrotron(RCS)of the CSNS,the repetition frequency is too high for the longitudinal motion to be fully adiabatic.Significant beam loss happens during the RF capture and initial acceleration of the injection period.To reduce the longitudinal beam loss,beam chopping and momentum offset painting methods are used in the RCS injection.This paper presents detailed studies on the longitudinal motion in the RCS by using the ORBIT simulations,which include different beam chopping factors,momentum offsets and RF voltage optimization.With a trade-off between the longitudinal beam loss and transverse incoherent tune shift that will also result in beam losses,optimized longitudinal painting schemes are obtained.

  16. Generalized Manning Condensation Model Captures the RNA Ion Atmosphere

    Science.gov (United States)

    Hayes, Ryan L.; Noel, Jeffrey K.; Mandic, Ana; Whitford, Paul C.; Sanbonmatsu, Karissa Y.; Mohanty, Udayan; Onuchic, José N.

    2016-01-01

    RNA is highly sensitive to the ionic environment, and typically requires Mg2+ to form compact structures. There is a need for models capable of describing the ion atmosphere surrounding RNA with quantitative accuracy. We present a model of RNA electrostatics and apply it within coarse-grained molecular dynamics simulation. The model treats Mg2+ ions explicitly to account for ion-ion correlations neglected by mean field theories. Since mean-field theories capture KCl well, it is treated implicitly by a generalized Manning counterion condensation model. The model extends Manning condensation to deal with arbitrary RNA conformations, non-limiting KCl concentrations, and the ion inaccessible volume of RNA. The model is tested against experimental measurements of the excess Mg2+ associated with the RNA, Γ2+, because Γ2+ is directly related to the Mg2+-RNA interaction free energy. The excellent agreement with experiment demonstrates the model captures the ionic dependence of the RNA free energy landscape. PMID:26197147

  17. On the simulation of tether-nets for space debris capture with Vortex Dynamics

    Science.gov (United States)

    Botta, Eleonora M.; Sharf, Inna; Misra, Arun K.; Teichmann, Marek

    2016-06-01

    Tether-nets are one of the more promising methods for the active removal of space debris. The aim of this paper is to study the dynamics of this type of systems in space, which is still not well-known and the simulation of which has multiple outstanding issues. In particular, the focus is on the deployment and capture phases of a net-based active debris removal mission, and on the effect of including the bending stiffness of the net threads on the dynamical characteristics of the net and on the computational efficiency. Lumped-parameter modeling of the net in Vortex Dynamics, without bending stiffness representation, is introduced first and validated then, against results obtained with an equivalent model in Matlab, using numerical simulations of the deployment phase. A model able to reproduce the bending stiffness of the net in Vortex Dynamics is proposed, and the outcome of a net deployment simulation is compared to the results of simulation without bending stiffness. A simulation of net-based capture of a derelict spacecraft is analyzed from the point of view of evaluating the effect of modeling the bending stiffness. From comparison of simulations with and without bending stiffness representation, it is found that bending stiffness has a significant influence both on the simulation results and on the computation time. When bending stiffness is included, the net is more resistant to the changes in its shape caused both by the motion of the corner masses (during deployment) and by the contact with the debris (during capture).

  18. An interface capturing scheme for modeling atomization in compressible flows

    Science.gov (United States)

    Garrick, Daniel P.; Hagen, Wyatt A.; Regele, Jonathan D.

    2017-09-01

    The study of atomization in supersonic flow is critical to ensuring reliable ignition of scramjet combustors under startup conditions. Numerical methods incorporating surface tension effects have largely focused on the incompressible regime as most atomization applications occur at low Mach numbers. Simulating surface tension effects in compressible flow requires robust numerical methods that can handle discontinuities caused by both shocks and material interfaces with high density ratios. In this work, a shock and interface capturing scheme is developed that uses the Harten-Lax-van Leer-Contact (HLLC) Riemann solver while a Tangent of Hyperbola for INterface Capturing (THINC) interface reconstruction scheme retains the fluid immiscibility condition in the volume fraction and phasic densities in the context of the five equation model. The approach includes the effects of compressibility, surface tension, and molecular viscosity. One and two-dimensional benchmark problems demonstrate the desirable interface sharpening and conservation properties of the approach. Simulations of secondary atomization of a cylindrical water column after its interaction with a shockwave show good qualitative agreement with experimentally observed behavior. Three-dimensional examples of primary atomization of a liquid jet in a Mach 2 crossflow demonstrate the robustness of the method.

  19. Molecular simulation of carbon dioxide adsorption for carbon capture and storage

    Science.gov (United States)

    Tenney, Craig M.

    Capture of CO2 from fossil fuel power plants and sequestration in unmineable coal seams are achievable methods for reducing atmospheric emissions of this greenhouse gas. To aid the development of effective CO2 capture and sequestration technologies, a series of molecular simulation studies were conducted to study the adsorption of CO2 and related species onto heterogeneous, solid adsorbents. To investigate the influence of surface heterogeneity upon adsorption behavior in activated carbons and coal, isotherms were generated via grand canonical Monte Carlo (GCMC) simulation for CO2 adsorption in slit-shaped pores with several variations of chemical and structural heterogeneity. Adsorption generally increased with increasing oxygen content and the presence of holes or furrows, which acted as preferred binding sites. To investigate the potential use of the flexible metal organic framework (MOF) Cu(BF4)2(bpy)2 (bpy=bipyridine) for CO2 capture, pure- and mixed-gas adsorption was simulated at conditions representative of power plant process streams. This MOF was chosen because it displays a novel behavior in which the crystal structure reversibly transitions from an empty, zero porosity state to a saturated, expanded state at the "gate pressure". Estimates of CO2 capacity above the gate pressure from GCMC simulations using a rigid MOF model showed good agreement with experiment. The CO2 adsorption capacity and estimated heats of adsorption are comparable to common physi-adsorbents under similar conditions. Mixed-gas simulations predicted CO2/N2 and CO2/H 2selectivities higher than typical microporous materials. To more closely investigate this gating effect, hybrid Monte-Carlo/molecular-dynamics (MCMD) was used to simulate adsorption using a flexible MOF model. Simulation cell volumes remained relatively constant at low gas pressures before increasing at higher pressure. Mixed-gas simulations predicted CO2/N 2 selectivities comparable to other microporous adsorbents. To

  20. Rcapture: Loglinear Models for Capture-Recapture in R

    Directory of Open Access Journals (Sweden)

    Sophie Baillargeon

    2007-04-01

    Full Text Available This article introduces Rcapture, an R package for capture-recapture experiments. The data for analysis consists of the frequencies of the observable capture histories over the t capture occasions of the experiment. A capture history is a vector of zeros and ones where one stands for a capture and zero for a miss. Rcapture can fit three types of models. With a closed population model, the goal of the analysis is to estimate the size N of the population which is assumed to be constant throughout the experiment. The estimator depends on the way in which the capture probabilities of the animals vary. Rcapture features several models for these capture probabilities that lead to different estimators for N. In an open population model, immigration and death occur between sampling periods. The estimation of survival rates is of primary interest. Rcapture can fit the basic Cormack-Jolly-Seber and Jolly-Seber model to such data. The third type of models fitted by Rcapture are robust design models. It features two levels of sampling; closed population models apply within primary periods and an open population model applies between periods. Most models in Rcapture have a loglinear form; they are fitted by carrying out a Poisson regression with the R function glm. Estimates of the demographic parameters of interest are derived from the loglinear parameter estimates; their variances are obtained by linearization. The novel feature of this package is the provision of several new options for modeling capture probabilities heterogeneity between animals in both closed population models and the primary periods of a robust design. It also implements many of the techniques developed by R. M. Cormack for open population models.

  1. A hierarchical model for spatial capture-recapture data

    Science.gov (United States)

    Royle, J. Andrew; Young, K.V.

    2008-01-01

    Estimating density is a fundamental objective of many animal population studies. Application of methods for estimating population size from ostensibly closed populations is widespread, but ineffective for estimating absolute density because most populations are subject to short-term movements or so-called temporary emigration. This phenomenon invalidates the resulting estimates because the effective sample area is unknown. A number of methods involving the adjustment of estimates based on heuristic considerations are in widespread use. In this paper, a hierarchical model of spatially indexed capture recapture data is proposed for sampling based on area searches of spatial sample units subject to uniform sampling intensity. The hierarchical model contains explicit models for the distribution of individuals and their movements, in addition to an observation model that is conditional on the location of individuals during sampling. Bayesian analysis of the hierarchical model is achieved by the use of data augmentation, which allows for a straightforward implementation in the freely available software WinBUGS. We present results of a simulation study that was carried out to evaluate the operating characteristics of the Bayesian estimator under variable densities and movement patterns of individuals. An application of the model is presented for survey data on the flat-tailed horned lizard (Phrynosoma mcallii) in Arizona, USA.

  2. Advanced modeling to accelerate the scale up of carbon capture technologies

    Energy Technology Data Exchange (ETDEWEB)

    Miller, David C.; Sun, XIN; Storlie, Curtis B.; Bhattacharyya, Debangsu

    2015-06-01

    In order to help meet the goals of the DOE carbon capture program, the Carbon Capture Simulation Initiative (CCSI) was launched in early 2011 to develop, demonstrate, and deploy advanced computational tools and validated multi-scale models to reduce the time required to develop and scale-up new carbon capture technologies. This article focuses on essential elements related to the development and validation of multi-scale models in order to help minimize risk and maximize learning as new technologies progress from pilot to demonstration scale.

  3. Dynamic Operation and Simulation of Post-Combustion CO2 Capture

    DEFF Research Database (Denmark)

    Gaspar, Jozsef; Gladis, Arne; Jørgensen, John Bagterp

    2016-01-01

    Thermal power need to operate, on a daily basis, with frequent and fast load changes to balance the large variations of intermittent energy sources, such as wind and solar energy. To make the integration of carbon capture to power plants economically and technically feasible, the carbon capture p...... for operation in future mixed green energy market. [All rights reserved Elsevier]....... the developed model (dCAPCO2) and the pilot measurements at both, transient and steady-state conditions. It outlines how the time needed to reach a new steady-state varies with respect to amine type and concentration. The simulation study reveals that it is essential to control the lean solvent flow to avoid...

  4. Multi-Phase CFD Modeling of Solid Sorbent Carbon Capture System

    Energy Technology Data Exchange (ETDEWEB)

    Ryan, Emily M.; DeCroix, David; Breault, Ronald W.; Xu, Wei; Huckaby, E. D.; Saha, Kringan; Darteville, Sebastien; Sun, Xin

    2013-07-30

    Computational fluid dynamics (CFD) simulations are used to investigate a low temperature post-combustion carbon capture reactor. The CFD models are based on a small scale solid sorbent carbon capture reactor design from ADA-ES and Southern Company. The reactor is a fluidized bed design based on a silica-supported amine sorbent. CFD models using both Eulerian-Eulerian and Eulerian-Lagrangian multi-phase modeling methods are developed to investigate the hydrodynamics and adsorption of carbon dioxide in the reactor. Models developed in both FLUENT® and BARRACUDA are presented to explore the strengths and weaknesses of state of the art CFD codes for modeling multi-phase carbon capture reactors. The results of the simulations show that the FLUENT® Eulerian-Lagrangian simulations (DDPM) are unstable for the given reactor design; while the BARRACUDA Eulerian-Lagrangian model is able to simulate the system given appropriate simplifying assumptions. FLUENT® Eulerian-Eulerian simulations also provide a stable solution for the carbon capture reactor given the appropriate simplifying assumptions.

  5. Multi-phase CFD modeling of solid sorbent carbon capture system

    Energy Technology Data Exchange (ETDEWEB)

    Ryan, E. M.; DeCroix, D.; Breault, Ronald W. [U.S. DOE; Xu, W.; Huckaby, E. David [U.S. DOE

    2013-01-01

    Computational fluid dynamics (CFD) simulations are used to investigate a low temperature post-combustion carbon capture reactor. The CFD models are based on a small scale solid sorbent carbon capture reactor design from ADA-ES and Southern Company. The reactor is a fluidized bed design based on a silica-supported amine sorbent. CFD models using both Eulerian–Eulerian and Eulerian–Lagrangian multi-phase modeling methods are developed to investigate the hydrodynamics and adsorption of carbon dioxide in the reactor. Models developed in both FLUENT® and BARRACUDA are presented to explore the strengths and weaknesses of state of the art CFD codes for modeling multi-phase carbon capture reactors. The results of the simulations show that the FLUENT® Eulerian–Lagrangian simulations (DDPM) are unstable for the given reactor design; while the BARRACUDA Eulerian–Lagrangian model is able to simulate the system given appropriate simplifying assumptions. FLUENT® Eulerian–Eulerian simulations also provide a stable solution for the carbon capture reactor given the appropriate simplifying assumptions.

  6. CO2 Capture with Ionic Liquids: Experiments and Molecular Simulations

    NARCIS (Netherlands)

    Ramdin, M.

    2015-01-01

    In this thesis, we investigated the potential of physical ILs for CO2 capture at pre-combustion and natural gas sweetening conditions. The performance of ILs with respect to conventional solvents is assessed in terms of gas solubilities and selectivities. The work discussed in this thesis consists o

  7. Carbon dioxide capture processes: Simulation, design and sensitivity analysis

    DEFF Research Database (Denmark)

    Zaman, Muhammad; Lee, Jay Hyung; Gani, Rafiqul

    2012-01-01

    Carbon dioxide is the main greenhouse gas and its major source is combustion of fossil fuels for power generation. The objective of this study is to carry out the steady-state sensitivity analysis for chemical absorption of carbon dioxide capture from flue gas using monoethanolamine solvent. First...

  8. CO2 Capture with Ionic Liquids: Experiments and Molecular Simulations

    NARCIS (Netherlands)

    Ramdin, M.

    2015-01-01

    In this thesis, we investigated the potential of physical ILs for CO2 capture at pre-combustion and natural gas sweetening conditions. The performance of ILs with respect to conventional solvents is assessed in terms of gas solubilities and selectivities. The work discussed in this thesis consists

  9. Capturing Appearance Variation in Active Appearance Models

    NARCIS (Netherlands)

    Van der Maaten, L.J.P.; Hendriks, E.A.

    2010-01-01

    The paper presents an extension of active appearance models (AAMs) that is better capable of dealing with the large variation in face appearance that is encountered in large multi-person face data sets. Instead of the traditional PCA-based texture model, our extended AAM employs a mixture of probabi

  10. Advanced virtual energy simulation training and research: IGCC with CO2 capture power plant

    Energy Technology Data Exchange (ETDEWEB)

    Zitney, S.; Liese, E.; Mahapatra, P.; Bhattacharyya, D.; Provost, G.

    2011-01-01

    AVESTAR Center is poised to develop a workforce well-prepared to operate and control commercial-scale gasification-based power plants capable of 90% pre-combustion CO{sub 2} capture and compression, as well as low sulfur, mercury, and NOx emissions. With additional support from the NETL-Regional University Alliance (NETL-RUA), the Center will educate and train engineering students and researchers by providing hands-on 'learning by operating' experience The AVESTAR Center also offers unique collaborative R&D opportunities in high-fidelity dynamic modeling, advanced process control, real-time optimization, and virtual plant simulation. Objectives and goals are aimed at safe and effective management of power generation systems for optimal efficiency, while protecting the environment. To add another dimension of realism to the AVESTAR experience, NETL will introduce an immersive training system with innovative three-dimensional virtual reality technology. Wearing a stereoscopic headset or eyewear, trainees will enter an interactive virtual environment that will allow them to move freely throughout the simulated 3-D facility to study and learn various aspects of IGCC plant operation, control, and safety. Such combined operator and immersive training systems go beyond traditional simulation and include more realistic scenarios, improved communication, and collaboration among co-workers.

  11. A markerless motion capture system to study musculoskeletal biomechanics: visual hull and simulated annealing approach.

    Science.gov (United States)

    Corazza, S; Mündermann, L; Chaudhari, A M; Demattio, T; Cobelli, C; Andriacchi, T P

    2006-06-01

    Human motion capture is frequently used to study musculoskeletal biomechanics and clinical problems, as well as to provide realistic animation for the entertainment industry. The most popular technique for human motion capture uses markers placed on the skin, despite some important drawbacks including the impediment to the motion by the presence of skin markers and relative movement between the skin where the markers are placed and the underlying bone. The latter makes it difficult to estimate the motion of the underlying bone, which is the variable of interest for biomechanical and clinical applications. A model-based markerless motion capture system is presented in this study, which does not require the placement of any markers on the subject's body. The described method is based on visual hull reconstruction and an a priori model of the subject. A custom version of adapted fast simulated annealing has been developed to match the model to the visual hull. The tracking capability and a quantitative validation of the method were evaluated in a virtual environment for a complete gait cycle. The obtained mean errors, for an entire gait cycle, for knee and hip flexion are respectively 1.5 degrees (+/-3.9 degrees ) and 2.0 degrees (+/-3.0 degrees ), while for knee and hip adduction they are respectively 2.0 degrees (+/-2.3 degrees ) and 1.1 degrees (+/-1.7 degrees ). Results for the ankle and shoulder joints are also presented. Experimental results captured in a gait laboratory with a real subject are also shown to demonstrate the effectiveness and potential of the presented method in a clinical environment.

  12. Using Chemistry Simulations: Attention Capture, Selective Amnesia and Inattentional Blindness

    Science.gov (United States)

    Rodrigues, Susan

    2011-01-01

    Twenty-one convenience sample student volunteers aged between 14-15 years worked in pairs (and one group of three) with two randomly allocated high quality conceptual (molecular level) and operational (mimicking wet labs) simulations. The volunteers were told they had five minutes to play, repeat, review, restart or stop the simulation, which in…

  13. Simulation of mercury capture by activated carbon injection in incinerator flue gas. 2. Fabric filter removal.

    Science.gov (United States)

    Scala, F

    2001-11-01

    Following a companion paper focused on the in-duct mercury capture in incinerator flue gas by powdered activated carbon injection, this paper is concerned with the additional mercury capture on the fabric filter cake, relevant to baghouse equipped facilities. A detailed model is presented for this process, based on material balances on mercury in both gaseous and adsorbed phases along the growing filter cake and inside the activated carbon particles,taking into account mass transfer resistances and adsorption kinetics. Several sorbents of practical interest have been considered, whose parameters have been evaluated from available literature data. The values and range of the operating variables have been chosen in order to simulate typical incinerators operating conditions. Results of simulations indicate that, contrary to the in-duct removal process, high mercury removal efficiencies can be obtained with moderate sorbent consumption, as a consequence of the effective gas/sorbent contacting on the filter. Satisfactory utilization of the sorbents is predicted, especially at long filtration times. The sorbent feed rate can be minimized by using a reactive sorbent and by lowering the filter temperature as much as possible. Minor benefits can be obtained also by decreasing the sorbent particle size and by increasing the cleaning cycle time of the baghouse compartments. Reverse-flow baghouses were more efficient than pulse-jet baghouses, while smoother operation can be obtained by increasing the number of baghouse compartments. Model results are compared with available relevant full scale data.

  14. Carbon dioxide capture processes: Simulation, design and sensitivity analysis

    DEFF Research Database (Denmark)

    Zaman, Muhammad; Lee, Jay Hyung; Gani, Rafiqul

    2012-01-01

    performance of the process to the L/G ratio to the absorber, CO2 lean solvent loadings, and striper pressure are presented in this paper. Based on the sensitivity analysis process optimization problems have been defined and solved and, a preliminary control structure selection has been made.......Carbon dioxide is the main greenhouse gas and its major source is combustion of fossil fuels for power generation. The objective of this study is to carry out the steady-state sensitivity analysis for chemical absorption of carbon dioxide capture from flue gas using monoethanolamine solvent. First...

  15. Carbon dioxide capture processes: Simulation, design and sensitivity analysis

    DEFF Research Database (Denmark)

    Zaman, Muhammad; Lee, Jay Hyung; Gani, Rafiqul

    2012-01-01

    performance of the process to the L/G ratio to the absorber, CO2 lean solvent loadings, and striper pressure are presented in this paper. Based on the sensitivity analysis process optimization problems have been defined and solved and, a preliminary control structure selection has been made.......Carbon dioxide is the main greenhouse gas and its major source is combustion of fossil fuels for power generation. The objective of this study is to carry out the steady-state sensitivity analysis for chemical absorption of carbon dioxide capture from flue gas using monoethanolamine solvent. First...

  16. Capturing Control Room Simulator Data with the HERA Database

    Energy Technology Data Exchange (ETDEWEB)

    Ronald Boring; April Whaley; Bruce Hallbert; Karin Laumann; Per Oivind Braarud; Andreas Bye; Erasmia Lois; Yung Hsien James Chang

    2007-08-01

    The Human Event Repository and Analysis (HERA) system has been developed as a tool for classifying and recording human performance data extracted from primary data sources. This paper reviews the process of extracting data from simulator studies for use in HERA. Simulator studies pose unique data collection challenges, both in types and quality of data measures, but such studies are ideally suited to gather operator performance data, including the full spectrum of performance shaping factors used in a HERA analysis. This paper provides suggestions for obtaining relevant human performance data for a HERA analysis from a control room simulator study and for inputting those data in a format suitable for HERA.

  17. Transient modeling of electrochemically assisted CO2 capture and release

    DEFF Research Database (Denmark)

    Singh, Shobhana; Stechel, Ellen B.; Buttry, Daniel A.

    2017-01-01

    The present work aims to develop a model of a new electrochemical CO2 separation and release technology. We present a one-dimensional transient model of an electrochemical cell for point source CO2 capture and release, which mainly focuses on the simultaneous mass transport and complex chemical...... reactions associated with the separation process. For concreteness, we use an ionic liquid (IL) with 2 M thiolate anion (RS−) in 1 M disulfide (RSSR) as an electrolyte in the electrochemical cell to capture, transport and release CO2 under standard operating conditions. We computationally solved the model...... to analyze the time-dependent behavior of CO2 capture and electro-migration transport across the cell length. Given high nonlinearity of the system, we used a finite element method (FEM) to numerically solve the coupled mass transport equations. The model describes the concentration profiles by taking...

  18. Animation of virtual mannequins, robot-like simulation or motion captures

    CERN Document Server

    Chablat, Damien

    2007-01-01

    In order to optimize the costs and time of design of the new products while improving their quality, concurrent engineering is based on the digital model of these products, the numerical model. However, in order to be able to avoid definitively physical model, old support of the design, without loss of information, new tools must be available. Especially, a tool making it possible to check simply and quickly the maintainability of complex mechanical sets using the numerical model is necessary. Since one decade, our team works on the creation of tool for the generation and the analysis of trajectories of virtual mannequins. The simulation of human tasks can be carried out either by robot-like simulation or by simulation by motion capture. This paper presents some results on the both two methods. The first method is based on a multi-agent system and on a digital mock-up technology, to assess an efficient path planner for a manikin or a robot for access and visibility task taking into account ergonomic constrain...

  19. U-238 Neutron Capture Gamma Cascade Generation and Transport Simulation for Capture Tank Response

    Science.gov (United States)

    1992-05-07

    6 1.3 Calculations of Yamamuro et al. .. .. .. .. .. ... ... ... .... 9 1.6 Review of Primary Experimental Work .. .. .. .. ... ... .... 10 1.6.1...modeling has been performed by Booth et al. 󈨋, Takahashi [8], and Yamamuro et al. ŝ 1. Experimental results are found in the work of Campion et al. 7101...quantity in the calcu- lation of the gamma-ray spectrum. In the Yamamuro paper, the Fermi-gas model formula is used and is referred to as the partial level

  20. Molecular simulations of nitrogen-doped hierarchical carbon adsorbents for post-combustion CO2 capture.

    Science.gov (United States)

    Psarras, Peter; He, Jiajun; Wilcox, Jennifer

    2016-10-19

    A present challenge in the mitigation of anthropogenic CO2 emissions involves the design of less energy- and water-intensive capture technologies. Sorbent-based capture represents a promising solution, as these materials have negligible water requirements and do not incur the heavy energy penalties associated with solvent regeneration. However, to be considered competitive with traditional technologies (i.e., MEA capture), these sorbents must exhibit a high CO2 loading capacity and high CO2/N2 selectivity. It has been reported that ultramicroporous character and surface nitrogen functionality are of great importance to the enhancement of CO2 capacity and CO2/N2 selectivity. However, the role of pore size in combination with surface functionality in the enhancement of these properties remains unclear. To investigate these effects, grand canonical Monte Carlo (GCMC) simulations were carried out on pure and N-functionalized 3-layer graphitic slit-pore models and compared to experimental results for two high performing materials reported elsewhere. We show that the quaternary, pyridinic, and especially the oxidized pyridinic group lend to enhanced performance, with the latter providing exceptional CO2 loading (4.31 mmol g(-1)) and CO2/N2 selectivity (138.3 : 1). Increasing surface nitrogen content resulted in enhanced loading and excellent CO2/N2 selectivity (45.8 : 1-55.9 : 1), provided that the sorbent has significant ultramicroporous character. Additionally, we elucidate a threshold pore width, under which N-functionalization becomes increasingly influential on performance parameters, and show how this threshold changes with application (PC vs. NGCC capture). Finally, we propose that an alternative functionality - the nitroso group - may be responsible for the enhanced performance of some recent materials reported in the literature.

  1. Computational Simulations of Magnetic Particle Capture in Arterial Flows

    NARCIS (Netherlands)

    Haverkort, J.W.; Kenjeres, S.; Kleijn, C.R.

    2009-01-01

    The aim of Magnetic Drug Targeting (MDT) is to concentrate drugs, attached to magnetic particles, in a specific part of the human body by applying a magnetic field. Computational simulations are performed of blood flow and magnetic particle motion in a left coronary artery and a carotid artery, usin

  2. Simulation modeling and arena

    CERN Document Server

    Rossetti, Manuel D

    2015-01-01

    Emphasizes a hands-on approach to learning statistical analysis and model building through the use of comprehensive examples, problems sets, and software applications With a unique blend of theory and applications, Simulation Modeling and Arena®, Second Edition integrates coverage of statistical analysis and model building to emphasize the importance of both topics in simulation. Featuring introductory coverage on how simulation works and why it matters, the Second Edition expands coverage on static simulation and the applications of spreadsheets to perform simulation. The new edition als

  3. CFD Simulations of a Regenerative Process for Carbon Dioxide Capture in Advanced Gasification Based Power Systems

    Energy Technology Data Exchange (ETDEWEB)

    Arastoopour, Hamid [Illinois Inst. of Technology, Chicago, IL (United States); Abbasian, Javad [Illinois Inst. of Technology, Chicago, IL (United States)

    2014-07-31

    This project describes the work carried out to prepare a highly reactive and mechanically strong MgO based sorbents and to develop a Population Balance Equations (PBE) approach to describe the evolution of the particle porosity distribution that is linked with Computational Fluid Dynamics (CFD) to perform simulations of the CO2 capture and sorbent regeneration. A large number of MgO-based regenerable sorbents were prepared using low cost and abundant dolomite as the base material. Among various preparation parameters investigated the potassium/magnesium (K/Mg) ratio was identified as the key variable affecting the reactivity and CO2 capacity of the sorbent. The optimum K/Mg ratio is about 0.15. The sorbent formulation HD52-P2 was identified as the “best” sorbent formulation and a large batch (one kg) of the sorbent was prepared for the detailed study. The results of parametric study indicate the optimum carbonation and regeneration temperatures are 360° and 500°C, respectively. The results also indicate that steam has a beneficial effect on the rate of carbonation and regeneration of the sorbent and that the reactivity and capacity of the sorbent decreases in the cycling process (sorbent deactivation). The results indicate that to achieve a high CO2 removal efficiency, the bed of sorbent should be operated at a temperature range of 370-410°C which also favors production of hydrogen through the WGS reaction. To describe the carbonation reaction kinetics of the MgO, the Variable Diffusivity shrinking core Model (VDM) was developed in this project, which was shown to accurately fit the experimental data. An important advantage of this model is that the changes in the sorbent conversion with time can be expressed in an explicit manner, which will significantly reduce the CFD computation time. A Computational Fluid Dynamic/Population Balance Equations (CFD/PBE) model was developed that accounts for the particle (sorbent) porosity distribution and a new version of

  4. A bottleneck model of set-specific capture.

    Science.gov (United States)

    Moore, Katherine Sledge; Weissman, Daniel H

    2014-01-01

    Set-specific contingent attentional capture is a particularly strong form of capture that occurs when multiple attentional sets guide visual search (e.g., "search for green letters" and "search for orange letters"). In this type of capture, a potential target that matches one attentional set (e.g. a green stimulus) impairs the ability to identify a temporally proximal target that matches another attentional set (e.g. an orange stimulus). In the present study, we investigated whether set-specific capture stems from a bottleneck in working memory or from a depletion of limited resources that are distributed across multiple attentional sets. In each trial, participants searched a rapid serial visual presentation (RSVP) stream for up to three target letters (T1-T3) that could appear in any of three target colors (orange, green, or lavender). The most revealing findings came from trials in which T1 and T2 matched different attentional sets and were both identified. In these trials, T3 accuracy was lower when it did not match T1's set than when it did match, but only when participants failed to identify T2. These findings support a bottleneck model of set-specific capture in which a limited-capacity mechanism in working memory enhances only one attentional set at a time, rather than a resource model in which processing capacity is simultaneously distributed across multiple attentional sets.

  5. Augmenting superpopulation capture-recapture models with population assignment data

    Science.gov (United States)

    Wen, Zhi; Pollock, Kenneth; Nichols, James; Waser, Peter

    2011-01-01

    Ecologists applying capture-recapture models to animal populations sometimes have access to additional information about individuals' populations of origin (e.g., information about genetics, stable isotopes, etc.). Tests that assign an individual's genotype to its most likely source population are increasingly used. Here we show how to augment a superpopulation capture-recapture model with such information. We consider a single superpopulation model without age structure, and split each entry probability into separate components due to births in situ and immigration. We show that it is possible to estimate these two probabilities separately. We first consider the case of perfect information about population of origin, where we can distinguish individuals born in situ from immigrants with certainty. Then we consider the more realistic case of imperfect information, where we use genetic or other information to assign probabilities to each individual's origin as in situ or outside the population. We use a resampling approach to impute the true population of origin from imperfect assignment information. The integration of data on population of origin with capture-recapture data allows us to determine the contributions of immigration and in situ reproduction to the growth of the population, an issue of importance to ecologists. We illustrate our new models with capture-recapture and genetic assignment data from a population of banner-tailed kangaroo rats Dipodomys spectabilis in Arizona.

  6. Modelling of tetrahydrofuran promoted gas hydrate systems for carbon dioxide capture processes

    DEFF Research Database (Denmark)

    Herslund, Peter Jørgensen; Thomsen, Kaj; Abildskov, Jens

    2014-01-01

    accurate descriptions of both fluid- and hydrate phase equilibria in the studied system and its subsystems. The developed model is applied to simulate two simplified, gas hydrate-based processes for post-combustion carbon dioxide capture from power station flue gases. The first process, an unpromoted...... hydrate process, operates isothermally at a temperature of 280. K. Applying three consecutive hydrate formation/dissociation stages (three-stage capture process), a carbon dioxide-rich product (97. mol%) is finally delivered at a temperature of 280. K and a pressure of 3.65. MPa. The minimum pressure...... requirement of the first stage is estimated to be 24.9. MPa, corresponding to the incipient hydrate dissociation pressure at 280. K for the considered flue gas. A second simulated carbon dioxide capture process uses tetrahydrofuran as a thermodynamic promoter to reduce the pressure requirements. By doing so...

  7. CFD Simulations of a Regenerative Process for Carbon Dioxide Capture in Advanced Gasification Based Power Systems

    Energy Technology Data Exchange (ETDEWEB)

    Arastoopour, Hamid [Illinois Inst. of Technology, Chicago, IL (United States); Abbasian, Javad [Illinois Inst. of Technology, Chicago, IL (United States)

    2014-07-31

    This project describes the work carried out to prepare a highly reactive and mechanically strong MgO based sorbents and to develop a Population Balance Equations (PBE) approach to describe the evolution of the particle porosity distribution that is linked with Computational Fluid Dynamics (CFD) to perform simulations of the CO2 capture and sorbent regeneration. A large number of MgO-based regenerable sorbents were prepared using low cost and abundant dolomite as the base material. Among various preparation parameters investigated the potassium/magnesium (K/Mg) ratio was identified as the key variable affecting the reactivity and CO2 capacity of the sorbent. The optimum K/Mg ratio is about 0.15. The sorbent formulation HD52-P2 was identified as the “best” sorbent formulation and a large batch (one kg) of the sorbent was prepared for the detailed study. The results of parametric study indicate the optimum carbonation and regeneration temperatures are 360° and 500°C, respectively. The results also indicate that steam has a beneficial effect on the rate of carbonation and regeneration of the sorbent and that the reactivity and capacity of the sorbent decreases in the cycling process (sorbent deactivation). The results indicate that to achieve a high CO2 removal efficiency, the bed of sorbent should be operated at a temperature range of 370-410°C which also favors production of hydrogen through the WGS reaction. To describe the carbonation reaction kinetics of the MgO, the Variable Diffusivity shrinking core Model (VDM) was developed in this project, which was shown to accurately fit the experimental data. An important advantage of this model is that the changes in the sorbent conversion with time can be expressed in an explicit manner, which will significantly reduce the CFD computation time. A Computational Fluid Dynamic/Population Balance Equations (CFD/PBE) model was developed that accounts for the particle (sorbent) porosity distribution and a new version of

  8. Simulation of Rogue Planet Encounters with the Solar System: Is Planet 9 a Captured Rogue?

    Science.gov (United States)

    Vesper, James; Mason, Paul A.

    2017-01-01

    Rogue, or free-floating, planets may be abundant in the Galaxy. Several have been observed in the solar neighborhood. They have been predicted to even outnumber stars by a large fraction, and may partially account for dark matter in the disk of the galaxy, as the result of circumbinary planet formation. We performed N-body simulations of rogue encounters with the solar system with a variety of impact parameters. We find that Jupiter mass and higher rogues leave a significant imprint on planetary system architecture. Rogue formation models are therefore constrained by observed planetary system structure. We speculate that if rogue planets are abundant as predicted, then, Planet 9 may be a captured rogue.

  9. Hierarchical calibration and validation of computational fluid dynamics models for solid sorbent-based carbon capture

    Energy Technology Data Exchange (ETDEWEB)

    Lai, Canhai; Xu, Zhijie; Pan, Wenxiao; Sun, Xin; Storlie, Curtis; Marcy, Peter; Dietiker, Jean-François; Li, Tingwen; Spenik, James

    2016-01-01

    To quantify the predictive confidence of a solid sorbent-based carbon capture design, a hierarchical validation methodology—consisting of basic unit problems with increasing physical complexity coupled with filtered model-based geometric upscaling has been developed and implemented. This paper describes the computational fluid dynamics (CFD) multi-phase reactive flow simulations and the associated data flows among different unit problems performed within the said hierarchical validation approach. The bench-top experiments used in this calibration and validation effort were carefully designed to follow the desired simple-to-complex unit problem hierarchy, with corresponding data acquisition to support model parameters calibrations at each unit problem level. A Bayesian calibration procedure is employed and the posterior model parameter distributions obtained at one unit-problem level are used as prior distributions for the same parameters in the next-tier simulations. Overall, the results have demonstrated that the multiphase reactive flow models within MFIX can be used to capture the bed pressure, temperature, CO2 capture capacity, and kinetics with quantitative accuracy. The CFD modeling methodology and associated uncertainty quantification techniques presented herein offer a solid framework for estimating the predictive confidence in the virtual scale up of a larger carbon capture device.

  10. Monte Carlo simulation of GCR neutron capture production of cosmogenic nuclides in stony meteorites and lunar surface

    Science.gov (United States)

    KolláR, D.; Michel, R.; Masarik, J.

    2006-03-01

    A purely physical model based on a Monte Carlo simulation of galactic cosmic ray (GCR) particle interaction with meteoroids is used to investigate neutron interactions down to thermal energies. Experimental and/or evaluated excitation functions are used to calculate neutron capture production rates as a function of the size of the meteoroid and the depth below its surface. Presented are the depth profiles of cosmogenic radionuclides 36Cl, 41Ca, 60Co, 59Ni, and 129I for meteoroid radii from 10 cm up to 500 cm and a 2π irradiation. Effects of bulk chemical composition on n-capture processes are studied and discussed for various chondritic and lunar compositions. The mean GCR particle flux over the last 300 ka was determined from the comparison of simulations with measured 41Ca activities in the Apollo 15 drill core. The determined value significantly differs from that obtained using equivalent models of spallation residue production.

  11. A data model that captures clinical reasoning about patient problems.

    Science.gov (United States)

    Barrows, R. C.; Johnson, S. B.

    1995-01-01

    We describe a data model that has been implemented for the CPMC Ambulatory Care System, and exemplify its function for patient problems. The model captures some nuances of clinical thinking about patients that are not accommodated in most other models, such as an evolution of clinical understanding about patient problems. A record of this understanding has clinical utility, and serves research interests as well as medical audit concerns. The model is described with an example, and advantages and limitations in the current implementation are discussed. PMID:8563311

  12. Modeling individual specific fish length from capture-recapture data using the von Bertalanffy growth curve.

    Science.gov (United States)

    Schofield, Matthew R; Barker, Richard J; Taylor, Peter

    2013-12-01

    We use Bayesian methods to explore fitting the von Bertalanffy length model to tag-recapture data. We consider two popular parameterizations of the von Bertalanffy model. The first models the data relative to age at first capture; the second models in terms of length at first capture. Using data from a rainbow trout Oncorhynchus mykiss study we explore the relationship between the assumptions and resulting inference using posterior predictive checking, cross validation and a simulation study. We find that untestable hierarchical assumptions placed on the nuisance parameters in each model can influence the resulting inference about parameters of interest. Researchers should carefully consider these assumptions when modeling growth from tag-recapture data. © 2013, The International Biometric Society.

  13. Computer Modeling and Simulation

    Energy Technology Data Exchange (ETDEWEB)

    Pronskikh, V. S. [Fermilab

    2014-05-09

    Verification and validation of computer codes and models used in simulation are two aspects of the scientific practice of high importance and have recently been discussed by philosophers of science. While verification is predominantly associated with the correctness of the way a model is represented by a computer code or algorithm, validation more often refers to model’s relation to the real world and its intended use. It has been argued that because complex simulations are generally not transparent to a practitioner, the Duhem problem can arise for verification and validation due to their entanglement; such an entanglement makes it impossible to distinguish whether a coding error or model’s general inadequacy to its target should be blamed in the case of the model failure. I argue that in order to disentangle verification and validation, a clear distinction between computer modeling (construction of mathematical computer models of elementary processes) and simulation (construction of models of composite objects and processes by means of numerical experimenting with them) needs to be made. Holding on to that distinction, I propose to relate verification (based on theoretical strategies such as inferences) to modeling and validation, which shares the common epistemology with experimentation, to simulation. To explain reasons of their intermittent entanglement I propose a weberian ideal-typical model of modeling and simulation as roles in practice. I suggest an approach to alleviate the Duhem problem for verification and validation generally applicable in practice and based on differences in epistemic strategies and scopes

  14. Dynamical modelling and control of a spacecraft-mounted manipulator capturing a spinning satellite

    Science.gov (United States)

    Cyril, Xavier; Jaar, Gilbert J.; Misra, Arun K.

    1995-01-01

    Issues associated with the modelling and control of a spacecraft-mounted manipulator capturing a spinning satellite are presented. The Lagrangian formulation is used to derive the dynamical equations of the system immediately following the capture. The formulation is carried out by writing Lagrange's equations for the individual bodies, and then assembling them to obtain the constrained dynamical equations of the system. The non-working constraint forces/torques are then eliminated by using the natural orthogonal complement which produces a set of independent dynamical equations. A control algorithm whose objective is to produce a set of feedback-linearized, homogeneous and uncoupled equations is designed and implemented. The initial conditions of the state variables needed to achieve smooth berthing of the satellite are computed, and the dynamics simulation of both the controlled and uncontrolled systems is carried out. The manipulator's structural flexibility is included in the dynamics simulation model.

  15. Theory Modeling and Simulation

    Energy Technology Data Exchange (ETDEWEB)

    Shlachter, Jack [Los Alamos National Laboratory

    2012-08-23

    Los Alamos has a long history in theory, modeling and simulation. We focus on multidisciplinary teams that tackle complex problems. Theory, modeling and simulation are tools to solve problems just like an NMR spectrometer, a gas chromatograph or an electron microscope. Problems should be used to define the theoretical tools needed and not the other way around. Best results occur when theory and experiments are working together in a team.

  16. Mathematical Capture of Human Data for Computer Model Building and Validation (Briefing Charts)

    Science.gov (United States)

    2014-04-03

    Send comments regarding this burden estimate or any other aspect of this collection of information, including suggestions for reducing this burden, to...continuation of the work to explore ways to improve the model development and validation processes. 15. SUBJECT TERMS Motion Capture, Crowd Management...defended by a non- lethal device: – No Defense (Baseline) – MRAD – Handheld stand-off NLW operated by Control Force • Simulated Projectile Weapon

  17. Simulation modeling of carcinogenesis.

    Science.gov (United States)

    Ellwein, L B; Cohen, S M

    1992-03-01

    A discrete-time simulation model of carcinogenesis is described mathematically using recursive relationships between time-varying model variables. The dynamics of cellular behavior is represented within a biological framework that encompasses two irreversible and heritable genetic changes. Empirical data and biological supposition dealing with both control and experimental animal groups are used together to establish values for model input variables. The estimation of these variables is integral to the simulation process as described in step-by-step detail. Hepatocarcinogenesis in male F344 rats provides the basis for seven modeling scenarios which illustrate the complexity of relationships among cell proliferation, genotoxicity, and tumor risk.

  18. Evaluation of Stochastic Rainfall Models in Capturing Climate Variability for Future Drought and Flood Risk Assessment

    Science.gov (United States)

    Chowdhury, A. F. M. K.; Lockart, N.; Willgoose, G. R.; Kuczera, G. A.; Kiem, A.; Nadeeka, P. M.

    2016-12-01

    One of the key objectives of stochastic rainfall modelling is to capture the full variability of climate system for future drought and flood risk assessment. However, it is not clear how well these models can capture the future climate variability when they are calibrated to Global/Regional Climate Model data (GCM/RCM) as these datasets are usually available for very short future period/s (e.g. 20 years). This study has assessed the ability of two stochastic daily rainfall models to capture climate variability by calibrating them to a dynamically downscaled RCM dataset in an east Australian catchment for 1990-2010, 2020-2040, and 2060-2080 epochs. The two stochastic models are: (1) a hierarchical Markov Chain (MC) model, which we developed in a previous study and (2) a semi-parametric MC model developed by Mehrotra and Sharma (2007). Our hierarchical model uses stochastic parameters of MC and Gamma distribution, while the semi-parametric model uses a modified MC process with memory of past periods and kernel density estimation. This study has generated multiple realizations of rainfall series by using parameters of each model calibrated to the RCM dataset for each epoch. The generated rainfall series are used to generate synthetic streamflow by using a SimHyd hydrology model. Assessing the synthetic rainfall and streamflow series, this study has found that both stochastic models can incorporate a range of variability in rainfall as well as streamflow generation for both current and future periods. However, the hierarchical model tends to overestimate the multiyear variability of wet spell lengths (therefore, is less likely to simulate long periods of drought and flood), while the semi-parametric model tends to overestimate the mean annual rainfall depths and streamflow volumes (hence, simulated droughts are likely to be less severe). Sensitivity of these limitations of both stochastic models in terms of future drought and flood risk assessment will be discussed.

  19. A stochastic evolutionary model for capturing human dynamics

    CERN Document Server

    Fenner, Trevor; Loizou, George

    2015-01-01

    The recent interest in human dynamics has led researchers to investigate the stochastic processes that explain human behaviour in various contexts. Here we propose a generative model to capture the dynamics of survival analysis, traditionally employed in clinical trials and reliability analysis in engineering. We derive a general solution for the model in the form of a product, and then a continuous approximation to the solution via the renewal equation describing age-structured population dynamics. This enables us to model a wide rage of survival distributions, according to the choice of the mortality distribution. We provide empirical evidence for the validity of the model from a longitudinal data set of popular search engine queries over 114 months, showing that the survival function of these queries is closely matched by the solution for our model with power-law mortality.

  20. Deployment models for commercialized carbon capture and storage.

    Science.gov (United States)

    Esposito, Richard A; Monroe, Larry S; Friedman, Julio S

    2011-01-01

    Even before technology matures and the regulatory framework for carbon capture and storage (CCS) has been developed, electrical utilities will need to consider the logistics of how widespread commercial-scale operations will be deployed. The framework of CCS will require utilities to adopt business models that ensure both safe and affordable CCS operations while maintaining reliable power generation. Physical models include an infrastructure with centralized CO(2) pipelines that focus geologic sequestration in pooled regional storage sites or supply CO(2) for beneficial use in enhanced oil recovery (EOR) and a dispersed plant model with sequestration operations which take place in close proximity to CO(2) capture. Several prototypical business models, including hybrids of these two poles, will be in play including a self-build option, a joint venture, and a pay at the gate model. In the self-build model operations are vertically integrated and utility owned and operated by an internal staff of engineers and geologists. A joint venture model stresses a partnership between the host site utility/owner's engineer and external operators and consultants. The pay to take model is turn-key external contracting to a third party owner/operator with cash positive fees paid out for sequestration and cash positive income for CO(2)-EOR. The selection of a business model for CCS will be based in part on the desire of utilities to be vertically integrated, source-sink economics, and demand for CO(2)-EOR. Another element in this decision will be how engaged a utility decides to be and the experience the utility has had with precommercial R&D activities. Through R&D, utilities would likely have already addressed or at least been exposed to the many technical, regulatory, and risk management issues related to successful CCS. This paper provides the framework for identifying the different physical and related prototypical business models that may play a role for electric utilities in

  1. Capture reactions at astrophysically relevant energies: extended gas target experiments and GEANT simulations

    CERN Document Server

    Kölle, V; Braitmayer, S E; Mohr, P J; Wilmes, S; Staudt, G; Hammer, J W; Jäger, M; Knee, H; Kunz, R; Mayer, A

    1999-01-01

    Several resonances of the capture reaction sup 2 sup 0 Ne(alpha, gamma) sup 2 sup 4 Mg were measured using an extended windowless gas target system. Detailed GEANT simulations were performed to derive the strength and the total width of the resonances from the measured yield curve. The crucial experimental parameters, which are mainly the density profile in the gas target and the efficiency of the gamma-ray detector, were analyzed by a comparison between the measured data and the corresponding simulation calculations. The excellent agreement between the experimental data and the simulations gives detailed insight into these parameters. (author)

  2. Modelling and simulation

    Energy Technology Data Exchange (ETDEWEB)

    Casetti, E.; Vogt, W.G.; Mickle, M.H.

    1984-01-01

    This conference includes papers on the uses of supercomputers, multiprocessors, artificial intelligence and expert systems in various energy applications. Topics considered include knowledge-based expert systems for power engineering, a solar air conditioning laboratory computer system, multivariable control systems, the impact of power system disturbances on computer systems, simulating shared-memory parallel computers, real-time image processing with multiprocessors, and network modeling and simulation of greenhouse solar systems.

  3. Conditional Methods in Modeling CO2 Capture from Coal Syngas

    Directory of Open Access Journals (Sweden)

    Dmitry N. Saulov

    2014-03-01

    Full Text Available Gasification of coal or biomass with in-situ CO2 capture is an emerging technology aiming to address the problem of climate change. Development of a CO2 sorbent with desirable properties and understanding the behavior of such a material in carbonation/calcination reactions is an important part of developing the technology. In this paper, we report experimental results describing the carbonation behavior of three synthetic CaO-based sorbents. We also present a physically-based model of the reactive transport processes in sorbent particles, which have complicated pore structures. This modeling is based on the conditional approach (i.e., conditional moment closure (CMC, which has proven to be successful in modeling reactive transport phenomena in porous media. The model predictions are in good agreement with the experimental data.

  4. Trap configuration and spacing influences parameter estimates in spatial capture-recapture models.

    Directory of Open Access Journals (Sweden)

    Catherine C Sun

    Full Text Available An increasing number of studies employ spatial capture-recapture models to estimate population size, but there has been limited research on how different spatial sampling designs and trap configurations influence parameter estimators. Spatial capture-recapture models provide an advantage over non-spatial models by explicitly accounting for heterogeneous detection probabilities among individuals that arise due to the spatial organization of individuals relative to sampling devices. We simulated black bear (Ursus americanus populations and spatial capture-recapture data to evaluate the influence of trap configuration and trap spacing on estimates of population size and a spatial scale parameter, sigma, that relates to home range size. We varied detection probability and home range size, and considered three trap configurations common to large-mammal mark-recapture studies: regular spacing, clustered, and a temporal sequence of different cluster configurations (i.e., trap relocation. We explored trap spacing and number of traps per cluster by varying the number of traps. The clustered arrangement performed well when detection rates were low, and provides for easier field implementation than the sequential trap arrangement. However, performance differences between trap configurations diminished as home range size increased. Our simulations suggest it is important to consider trap spacing relative to home range sizes, with traps ideally spaced no more than twice the spatial scale parameter. While spatial capture-recapture models can accommodate different sampling designs and still estimate parameters with accuracy and precision, our simulations demonstrate that aspects of sampling design, namely trap configuration and spacing, must consider study area size, ranges of individual movement, and home range sizes in the study population.

  5. Trap configuration and spacing influences parameter estimates in spatial capture-recapture models.

    Science.gov (United States)

    Sun, Catherine C; Fuller, Angela K; Royle, J Andrew

    2014-01-01

    An increasing number of studies employ spatial capture-recapture models to estimate population size, but there has been limited research on how different spatial sampling designs and trap configurations influence parameter estimators. Spatial capture-recapture models provide an advantage over non-spatial models by explicitly accounting for heterogeneous detection probabilities among individuals that arise due to the spatial organization of individuals relative to sampling devices. We simulated black bear (Ursus americanus) populations and spatial capture-recapture data to evaluate the influence of trap configuration and trap spacing on estimates of population size and a spatial scale parameter, sigma, that relates to home range size. We varied detection probability and home range size, and considered three trap configurations common to large-mammal mark-recapture studies: regular spacing, clustered, and a temporal sequence of different cluster configurations (i.e., trap relocation). We explored trap spacing and number of traps per cluster by varying the number of traps. The clustered arrangement performed well when detection rates were low, and provides for easier field implementation than the sequential trap arrangement. However, performance differences between trap configurations diminished as home range size increased. Our simulations suggest it is important to consider trap spacing relative to home range sizes, with traps ideally spaced no more than twice the spatial scale parameter. While spatial capture-recapture models can accommodate different sampling designs and still estimate parameters with accuracy and precision, our simulations demonstrate that aspects of sampling design, namely trap configuration and spacing, must consider study area size, ranges of individual movement, and home range sizes in the study population.

  6. Camera response prediction for various capture settings using the spectral sensitivity and crosstalk model.

    Science.gov (United States)

    Qiu, Jueqin; Xu, Haisong

    2016-09-01

    In this paper, a camera response formation model is proposed to accurately predict the responses of images captured under various exposure settings. Differing from earlier works that estimated the camera relative spectral sensitivity, our model constructs the physical spectral sensitivity curves and device-dependent parameters that convert the absolute spectral radiances of target surfaces to the camera readout responses. With this model, the camera responses to miscellaneous combinations of surfaces and illuminants could be accurately predicted. Thus, creating an "imaging simulator" by using the colorimetric and photometric research based on the cameras would be of great convenience.

  7. Simulation of Quasi-Adiabatic Beam Capture into Acceleration at the Nuclotron

    CERN Document Server

    Volkov, V I; Issinsky, I B; Kovalenko, A D

    2003-01-01

    The routine RF system being used at the Nuclotron allows one to inject the beam at ramping magnetic field with following acceleration at constant amplitude of accelerating voltage. At these conditions at least a half of the particles circulating in the vacuum chamber after injection is not captured in longitudinal acceptance. At the same time vacuum chamber sizes permit to extend the momentum spread of the beam enough to make gymnastic with it inside the stable zone of longitudinal phase space on the flat magnetic field at injection. A quasi-adiabatic capture was considered for increasing the Nuclotron beam intensity. Simulation of such a kind of process with subsequent acceleration was performed. It was shown that in this case it is possible to capture and accelerate up to 100 % of the injected beam.

  8. Model based adaptive control of a continuous capture process for monoclonal antibodies production.

    Science.gov (United States)

    Steinebach, Fabian; Angarita, Monica; Karst, Daniel J; Müller-Späth, Thomas; Morbidelli, Massimo

    2016-04-29

    A two-column capture process for continuous processing of cell-culture supernatant is presented. Similar to other multicolumn processes, this process uses sequential countercurrent loading of the target compound in order maximize resin utilization and productivity for a given product yield. The process was designed using a novel mechanistic model for affinity capture, which takes both specific adsorption as well as transport through the resin beads into account. Simulations as well as experimental results for the capture of an IgG antibody are discussed. The model was able to predict the process performance in terms of yield, productivity and capacity utilization. Compared to continuous capture with two columns operated batch wise in parallel, a 2.5-fold higher capacity utilization was obtained for the same productivity and yield. This results in an equal improvement in product concentration and reduction of buffer consumption. The developed model was used not only for the process design and optimization but also for its online control. In particular, the unit operating conditions are changed in order to maintain high product yield while optimizing the process performance in terms of capacity utilization and buffer consumption also in the presence of changing upstream conditions and resin aging.

  9. Modeling misidentification errors that result from use of genetic tags in capture-recapture studies

    Science.gov (United States)

    Yoshizaki, J.; Brownie, C.; Pollock, K.H.; Link, W.A.

    2011-01-01

    Misidentification of animals is potentially important when naturally existing features (natural tags) such as DNA fingerprints (genetic tags) are used to identify individual animals. For example, when misidentification leads to multiple identities being assigned to an animal, traditional estimators tend to overestimate population size. Accounting for misidentification in capture-recapture models requires detailed understanding of the mechanism. Using genetic tags as an example, we outline a framework for modeling the effect of misidentification in closed population studies when individual identification is based on natural tags that are consistent over time (non-evolving natural tags). We first assume a single sample is obtained per animal for each capture event, and then generalize to the case where multiple samples (such as hair or scat samples) are collected per animal per capture occasion. We introduce methods for estimating population size and, using a simulation study, we show that our new estimators perform well for cases with moderately high capture probabilities or high misidentification rates. In contrast, conventional estimators can seriously overestimate population size when errors due to misidentification are ignored. ?? 2009 Springer Science+Business Media, LLC.

  10. Phase-field simulations of particle capture during the directional solidification of silicon

    Science.gov (United States)

    Aufgebauer, Henning; Kundin, Julia; Emmerich, Heike; Azizi, Maral; Reimann, Christian; Friedrich, Jochen; Jauß, Thomas; Sorgenfrei, Tina; Cröll, Arne

    2016-07-01

    We present a phase-field model for particle capture during directional solidification. Its predictions for critical growth velocities for particles of different sizes are compared with experimental results for capture of silicon carbide (SiC) particles during directional solidification of silicon. The phase-field model allows us to systematically test the influence of different assumptions about attractive and repulsive forces and the capture mechanisms, including the effects of particle shape and of partial engulfment of the particle by the interface. We identify common properties of models that show agreement with experiments, trying to determine the underlying physical effects by abductive inference. We find that predictions vary only slightly between models with different repulsive forces and that the shape of the particle can have a larger effect on the critical growth velocity than the exact nature of the repulsive force or the capture process. We assess to what extent a good description of experimental critical growth velocities implies that the model accurately describes the actual physical processes and propose additional ways to test the validity of models.

  11. Rose bush leaf and internode expansion dynamics: analysis and development of a model capturing interplant variability

    Directory of Open Access Journals (Sweden)

    Sabine eDemotes-Mainard

    2013-10-01

    Full Text Available Bush rose architecture, among other factors, such as plant health, determines plant visual quality. The commercial product is the individual plant and interplant variability may be high within a crop. Thus, both mean plant architecture and interplant variability should be studied. Expansion is an important feature of architecture, but it has been little studied at the level of individual organs in bush roses. We investigated the expansion kinetics of primary shoot organs, to develop a model reproducing the organ expansion of real crops from non destructive input variables. We took interplant variability in expansion kinetics and the model’s ability to simulate this variability into account. Changes in leaflet and internode dimensions over thermal time were recorded for primary shoot expansion, on 83 plants from three crops grown in different climatic conditions and densities. An empirical model was developed, to reproduce organ expansion kinetics for individual plants of a real crop of bush rose primary shoots. Leaflet or internode length was simulated as a logistic function of thermal time. The model was evaluated by cross-validation. We found that differences in leaflet or internode expansion kinetics between phytomer positions and between plants at a given phytomer position were due mostly to large differences in time of organ expansion and expansion rate, rather than differences in expansion duration. Thus, in the model, the parameters linked to expansion duration were predicted by values common to all plants, whereas variability in final size and organ expansion time was captured by input data. The model accurately simulated leaflet and internode expansion for individual plants (RMSEP = 7.3% and 10.2% of final length, respectively. Thus, this study defines the measurements required to simulate expansion and provides the first model simulating organ expansion in rosebush to capture interplant variability.

  12. Multi-metric calibration of hydrological model to capture overall flow regimes

    Science.gov (United States)

    Zhang, Yongyong; Shao, Quanxi; Zhang, Shifeng; Zhai, Xiaoyan; She, Dunxian

    2016-08-01

    Flow regimes (e.g., magnitude, frequency, variation, duration, timing and rating of change) play a critical role in water supply and flood control, environmental processes, as well as biodiversity and life history patterns in the aquatic ecosystem. The traditional flow magnitude-oriented calibration of hydrological model was usually inadequate to well capture all the characteristics of observed flow regimes. In this study, we simulated multiple flow regime metrics simultaneously by coupling a distributed hydrological model with an equally weighted multi-objective optimization algorithm. Two headwater watersheds in the arid Hexi Corridor were selected for the case study. Sixteen metrics were selected as optimization objectives, which could represent the major characteristics of flow regimes. Model performance was compared with that of the single objective calibration. Results showed that most metrics were better simulated by the multi-objective approach than those of the single objective calibration, especially the low and high flow magnitudes, frequency and variation, duration, maximum flow timing and rating. However, the model performance of middle flow magnitude was not significantly improved because this metric was usually well captured by single objective calibration. The timing of minimum flow was poorly predicted by both the multi-metric and single calibrations due to the uncertainties in model structure and input data. The sensitive parameter values of the hydrological model changed remarkably and the simulated hydrological processes by the multi-metric calibration became more reliable, because more flow characteristics were considered. The study is expected to provide more detailed flow information by hydrological simulation for the integrated water resources management, and to improve the simulation performances of overall flow regimes.

  13. Hollow Fiber Membrane Contactors for CO2 Capture: Modeling and Up-Scaling to CO2 Capture for an 800 MWe Coal Power Station

    Directory of Open Access Journals (Sweden)

    Kimball Erin

    2014-11-01

    Full Text Available A techno-economic analysis was completed to compare the use of Hollow Fiber Membrane Modules (HFMM with the more conventional structured packing columns as the absorber in amine-based CO2 capture systems for power plants. In order to simulate the operation of industrial scale HFMM systems, a two-dimensional model was developed and validated based on results of a laboratory scale HFMM. After successful experiments and validation of the model, a pilot scale HFMM was constructed and simulated with the same model. The results of the simulations, from both sizes of HFMM, were used to assess the feasibility of further up-scaling to a HFMM system to capture the CO2 from an 800 MWe power plant. The system requirements – membrane fiber length, total contact surface area, and module volume – were determined from simulations and used for an economic comparison with structured packing columns. Results showed that a significant cost reduction of at least 50% is required to make HFMM competitive with structured packing columns. Several factors for the design of industrial scale HFMM require further investigation, such as the optimal aspect ratio (module length/diameter, membrane lifetime, and casing material and shape, in addition to the need to reduce the overall cost. However, HFMM were also shown to have the advantages of having a higher contact surface area per unit volume and modular scale-up, key factors for applications requiring limited footprints or flexibility in configuration.

  14. Breeding return times and abundance in capture-recapture models.

    Science.gov (United States)

    Pledger, Shirley; Baker, Edward; Scribner, Kim

    2013-12-01

    For many long-lived animal species, individuals do not breed every year, and are often not accessible during non-breeding periods. Individuals exhibit site fidelity if they return to the same breeding colony or spawning ground when they breed. If capture and recapture is only possible at the breeding site, temporary emigration models are used to allow for only a subset of the animals being present in any given year. Most temporary emigration models require the use of the robust sampling design, and their focus is usually on probabilities of annual survival and of transition between breeding and non-breeding states. We use lake sturgeon (Acipenser fulvescens) data from a closed population where only a simple (one sample per year) sampling scheme is possible, and we also wish to estimate abundance as well as sex-specific survival and breeding return time probabilities. By adding return time parameters to the Schwarz-Arnason version of the Jolly-Seber model, we have developed a new likelihood-based model which yields plausible estimates of abundance, survival, transition and return time parameters. An important new finding from investigation of the model is the overestimation of abundance if a Jolly-Seber model is used when Markovian temporary emigration is present.

  15. Method and Process for the Creation of Modeling and Simulation Tools for Human Crowd Behavior

    Science.gov (United States)

    2014-07-23

    measurements under controlled conditions. These methods and measures include motion capture of subjects in a laboratory environment to derive coefficients for...Experimentation, Empirical Data, Behavioral Models, Target Behavioral Response Laboratory, Crowds, Predictive Crowd Modeling, Motion Capture 16...MRAD – Handheld stand-off NLW operated by Control Force • Simulated Projectile Weapon • Simulated Handheld Directed Energy NLW (VDE) – Simulated

  16. A Comparison of Grizzly Bear Demographic Parameters Estimated from Non-Spatial and Spatial Open Population Capture-Recapture Models.

    Directory of Open Access Journals (Sweden)

    Jesse Whittington

    Full Text Available Capture-recapture studies are frequently used to monitor the status and trends of wildlife populations. Detection histories from individual animals are used to estimate probability of detection and abundance or density. The accuracy of abundance and density estimates depends on the ability to model factors affecting detection probability. Non-spatial capture-recapture models have recently evolved into spatial capture-recapture models that directly include the effect of distances between an animal's home range centre and trap locations on detection probability. Most studies comparing non-spatial and spatial capture-recapture biases focussed on single year models and no studies have compared the accuracy of demographic parameter estimates from open population models. We applied open population non-spatial and spatial capture-recapture models to three years of grizzly bear DNA-based data from Banff National Park and simulated data sets. The two models produced similar estimates of grizzly bear apparent survival, per capita recruitment, and population growth rates but the spatial capture-recapture models had better fit. Simulations showed that spatial capture-recapture models produced more accurate parameter estimates with better credible interval coverage than non-spatial capture-recapture models. Non-spatial capture-recapture models produced negatively biased estimates of apparent survival and positively biased estimates of per capita recruitment. The spatial capture-recapture grizzly bear population growth rates and 95% highest posterior density averaged across the three years were 0.925 (0.786-1.071 for females, 0.844 (0.703-0.975 for males, and 0.882 (0.779-0.981 for females and males combined. The non-spatial capture-recapture population growth rates were 0.894 (0.758-1.024 for females, 0.825 (0.700-0.948 for males, and 0.863 (0.771-0.957 for both sexes. The combination of low densities, low reproductive rates, and predominantly negative

  17. A Comparison of Grizzly Bear Demographic Parameters Estimated from Non-Spatial and Spatial Open Population Capture-Recapture Models.

    Science.gov (United States)

    Whittington, Jesse; Sawaya, Michael A

    2015-01-01

    Capture-recapture studies are frequently used to monitor the status and trends of wildlife populations. Detection histories from individual animals are used to estimate probability of detection and abundance or density. The accuracy of abundance and density estimates depends on the ability to model factors affecting detection probability. Non-spatial capture-recapture models have recently evolved into spatial capture-recapture models that directly include the effect of distances between an animal's home range centre and trap locations on detection probability. Most studies comparing non-spatial and spatial capture-recapture biases focussed on single year models and no studies have compared the accuracy of demographic parameter estimates from open population models. We applied open population non-spatial and spatial capture-recapture models to three years of grizzly bear DNA-based data from Banff National Park and simulated data sets. The two models produced similar estimates of grizzly bear apparent survival, per capita recruitment, and population growth rates but the spatial capture-recapture models had better fit. Simulations showed that spatial capture-recapture models produced more accurate parameter estimates with better credible interval coverage than non-spatial capture-recapture models. Non-spatial capture-recapture models produced negatively biased estimates of apparent survival and positively biased estimates of per capita recruitment. The spatial capture-recapture grizzly bear population growth rates and 95% highest posterior density averaged across the three years were 0.925 (0.786-1.071) for females, 0.844 (0.703-0.975) for males, and 0.882 (0.779-0.981) for females and males combined. The non-spatial capture-recapture population growth rates were 0.894 (0.758-1.024) for females, 0.825 (0.700-0.948) for males, and 0.863 (0.771-0.957) for both sexes. The combination of low densities, low reproductive rates, and predominantly negative population growth

  18. Spatial capture-recapture models allowing Markovian transience or dispersal

    Science.gov (United States)

    Royle, J. Andrew; Fuller, Angela K.; Sutherland, Chris

    2016-01-01

    Spatial capture–recapture (SCR) models are a relatively recent development in quantitative ecology, and they are becoming widely used to model density in studies of animal populations using camera traps, DNA sampling and other methods which produce spatially explicit individual encounter information. One of the core assumptions of SCR models is that individuals possess home ranges that are spatially stationary during the sampling period. For many species, this assumption is unlikely to be met and, even for species that are typically territorial, individuals may disperse or exhibit transience at some life stages. In this paper we first conduct a simulation study to evaluate the robustness of estimators of density under ordinary SCR models when dispersal or transience is present in the population. Then, using both simulated and real data, we demonstrate that such models can easily be described in the BUGS language providing a practical framework for their analysis, which allows us to evaluate movement dynamics of species using capture–recapture data. We find that while estimators of density are extremely robust, even to pathological levels of movement (e.g., complete transience), the estimator of the spatial scale parameter of the encounter probability model is confounded with the dispersal/transience scale parameter. Thus, use of ordinary SCR models to make inferences about density is feasible, but interpretation of SCR model parameters in relation to movement should be avoided. Instead, when movement dynamics are of interest, such dynamics should be parameterized explicitly in the model.

  19. Assessment of Numerical Treatments in Interface Capturing Simulations for Surface-Tension-Driven Interface Motion

    Directory of Open Access Journals (Sweden)

    Abhinav Dhar

    2015-03-01

    Full Text Available Effects of numerical treatments for the surface tension evaluation on predictions of the motions of droplets ranging from micron to sub-micron meters were investigated. Various combinations of schemes for evaluating the normal to the interface and interface curvature were examined, i.e. the ALE (arbitrary Lagrangian-eulerian like scheme and BFA (balanced-force algorithm for the normal vector and CSF (continuum surface force and HF (height function for the interface curvature. The interface motion was predicted using THAINC (tangent of hyperbola with adaptive slope for interface capturing proposed in our previous study. Numerical errors in pressure and velocity were examined for neutrally buoyant drops of 1 mm in radius to validate the code, which confirmed that the results were similar to those reported in literature: the combination of BFA and HF gave the lowest errors. The droplet size was reduced to 0.1 mm to investigate the accuracy of the schemes for droplet sizes found in industrial coating processes. The static contact angle was then taken into account in the code. The effect of implementation on the errors was examined. The reduction of droplet sizes and implementation of contact angle had no substantial effect on the order of errors. A model for the dynamic contact angle was also implemented and the wetting behaviour of a drop of 1.14 mm in radius was well predicted. Finally a simulation of the wetting behaviour of a sub-micron meter droplet demonstrated that the present code combining BFA, HF and the dynamic contact angle model is accurate in predicting the motion of sub-micron meter droplets.

  20. Terminal spacecraft rendezvous and capture with LASSO model predictive control

    Science.gov (United States)

    Hartley, Edward N.; Gallieri, Marco; Maciejowski, Jan M.

    2013-11-01

    The recently investigated ℓasso model predictive control (MPC) is applied to the terminal phase of a spacecraft rendezvous and capture mission. The interaction between the cost function and the treatment of minimum impulse bit is also investigated. The propellant consumption with ℓasso MPC for the considered scenario is noticeably less than with a conventional quadratic cost and control actions are sparser in time. Propellant consumption and sparsity are competitive with those achieved using a zone-based ℓ1 cost function, whilst requiring fewer decision variables in the optimisation problem than the latter. The ℓasso MPC is demonstrated to meet tighter specifications on control precision and also avoids the risk of undesirable behaviours often associated with pure ℓ1 stage costs.

  1. Modeling and Simulation of Hydraulic Engine Mounts

    Institute of Scientific and Technical Information of China (English)

    DUAN Shanzhong; Marshall McNea

    2012-01-01

    Hydraulic engine mounts are widely used in automotive powertrains for vibration isolation.A lumped mechanical parameter model is a traditional approach to model and simulate such mounts.This paper presents a dynamical model of a passive hydraulic engine mount with a double-chamber,an inertia track,a decoupler,and a plunger.The model is developed based on analogy between electrical systems and mechanical-hydraulic systems.The model is established to capture both low and high frequency dynatmic behaviors of the hydraulic mount.The model will be further used to find the approximate pulse responses of the mounts in terms of the force transmission and top chamber pressure.The close form solution from the simplifiod linear model may provide some insight into the highly nonlinear behavior of the mounts.Based on the model,computer simulation has been carried out to study dynamic performance of the hydraulic mount.

  2. The Planets-Capture Model of V838 Monocerotis

    CERN Document Server

    Retter, A; Siess, L; Levinson, A; Marom, A; Retter, Alon; Zhang, Bing; Siess, Lionel; Levinson, Amir; Marom, Ariel

    2006-01-01

    The planets capture model for the eruption of V838 Mon is discussed. We used three methods to estimate the location where the planets were consumed. There is a nice consistency for the results of the three different methods, and we find that the typical stopping / slowing radius for the planets is about 1Ro. The three peaks in the optical light curve of V838 Mon are either explained by the swallowing of three planets at different radii or by three steps in the slowing down process of a single planet. We discuss the other models offered for the outburst of V838 Mon, and conclude that the binary merger model and the planet/s scenario seem to be the most promising. These two models have several similarities, and the main differences are the stellar evolutionary stage, and the mass of the accreted material. We show that the energy emitted in the V838 Mon event is consistent with the planets scenario. We suggest a few explanations for the trigger for the outburst and for the double structure of the optical peaks i...

  3. Cellular Scanning Strategy for Selective Laser Melting: Capturing Thermal Trends with a Low-Fidelity, Pseudo-Analytical Model

    Directory of Open Access Journals (Sweden)

    Sankhya Mohanty

    2014-01-01

    Full Text Available Simulations of additive manufacturing processes are known to be computationally expensive. The resulting large runtimes prohibit their application in secondary analysis requiring several complete simulations such as optimization studies, and sensitivity analysis. In this paper, a low-fidelity pseudo-analytical model has been introduced to enable such secondary analysis. The model has been able to mimic a finite element model and was able to capture the thermal trends associated with the process. The model has been validated and subsequently applied in a small optimization case study. The pseudo-analytical modelling technique is established as a fast tool for primary modelling investigations.

  4. Policy Capturing with Local Models: The Application of the AID technique in Modeling Judgment

    Science.gov (United States)

    1972-12-01

    or coding phases have upon the derived policy modelo . Particularly important aspects of these subtasks include: 1) Initial identification and coding of...Applying AID4UT/AIDTRE in Policy Capturing: The experience gained thus far in applying AID4UT/AIDTREl to Policy Capturing is extensive in the sense ...that numerous models have been attempted and produced, but limited in the sense that these models were all for a particular decision process, except for

  5. Modeling and Testing of Phase Transition-Based Deployable Systems for Small Body Sample Capture

    Science.gov (United States)

    Quadrelli, Marco; Backes, Paul; Wilkie, Keats; Giersch, Lou; Quijano, Ubaldo; Keim, Jason; Mukherjee, Rudranarayan

    2009-01-01

    This paper summarizes the modeling, simulation, and testing work related to the development of technology to investigate the potential that shape memory actuation has to provide mechanically simple and affordable solutions for delivering assets to a surface and for sample capture and return. We investigate the structural dynamics and controllability aspects of an adaptive beam carrying an end-effector which, by changing equilibrium phases is able to actively decouple the end-effector dynamics from the spacecraft dynamics during the surface contact phase. Asset delivery and sample capture and return are at the heart of several emerging potential missions to small bodies, such as asteroids and comets, and to the surface of large bodies, such as Titan.

  6. Modeling post-combustion CO2 capture with amine solvents

    OpenAIRE

    Léonard, Grégoire; Heyen, Georges

    2010-01-01

    In order to avoid the emission of large amounts of greenhouse gas, CO2 capture in fossil fuel power plants and subsequent underground CO2 sequestration is studied. The capture occurs by reactive CO2 absorption into chemical solvent systems at moderate temperature (~50°C) followed by solvent regeneration at higher temperature (~120°C). So far, the most employed solvent for acid gas capture is monoethanolamine (MEA). One main drawback of this technology is the high energy consumption necessary ...

  7. From capture to simulation: connecting forward and inverse problems in fluids

    KAUST Repository

    Gregson, James

    2014-07-27

    We explore the connection between fluid capture, simulation and proximal methods, a class of algorithms commonly used for inverse problems in image processing and computer vision. Our key finding is that the proximal operator constraining fluid velocities to be divergence-free is directly equivalent to the pressure-projection methods commonly used in incompressible flow solvers. This observation lets us treat the inverse problem of fluid tracking as a constrained flow problem all while working in an efficient, modular framework. In addition it lets us tightly couple fluid simulation into flow tracking, providing a global prior that significantly increases tracking accuracy and temporal coherence as compared to previous techniques. We demonstrate how we can use these improved results for a variety of applications, such as re-simulation, detail enhancement, and domain modification. We furthermore give an outlook of the applications beyond fluid tracking that our proximal operator framework could enable by exploring the connection of deblurring and fluid guiding.

  8. Do electron-capture supernovae make neutron stars? First multidimensional hydrodynamic simulations of the oxygen deflagration

    CERN Document Server

    Jones, Samuel; Pakmor, Ruediger; Seitenzahl, Ivo R; Ohlmann, Sebastian T; Edelmann, Philipp V F

    2016-01-01

    In the classical picture, electron-capture supernovae and the accretion-induced collapse of oxygen-neon white dwarfs undergo an oxygen deflagration phase before gravitational collapse produces a neutron star. Such core collapse events are postulated to explain several astronomical phenomena. In this work, the oxygen deflagration phase is simulated for the first time using multidimensional hydrodynamics. By simulating the oxygen deflagration with multidimensional hydrodynamics and a level-set based flame approach, new insights can be gained into the explosive deaths of 8--10 solar-mass stars and oxygen-neon white dwarfs accreting material from a binary companion star. The main aim is to determine whether these events are thermonuclear or core-collapse supernova explosions, and hence whether neutron stars are formed by such phenomena. The oxygen deflagration is simulated in oxygen-neon cores with three different central ignition densities. The intermediate density case is perhaps the most realistic based on rec...

  9. Wake modeling and simulation

    DEFF Research Database (Denmark)

    Larsen, Gunner Chr.; Madsen Aagaard, Helge; Larsen, Torben J.;

    , have the potential to include also mutual wake interaction phenomenons. The basic conjecture behind the dynamic wake meandering (DWM) model is that wake transportation in the atmospheric boundary layer is driven by the large scale lateral- and vertical turbulence components. Based on this conjecture...... and trailed vorticity, has been approached by a simple semi-empirical model essentially based on an eddy viscosity philosophy. Contrary to previous attempts to model wake loading, the DWM approach opens for a unifying description in the sense that turbine power- and load aspects can be treated simultaneously...... methodology has been implemented in the aeroelastic code HAWC2, and example simulations of wake situations, from the small Tjæreborg wind farm, have been performed showing satisfactory agreement between predictions and measurements...

  10. Capture-recapture survival models taking account of transients

    Science.gov (United States)

    Pradel, R.; Hines, J.E.; Lebreton, J.D.; Nichols, J.D.

    1997-01-01

    The presence of transient animals, common enough in natural populations, invalidates the estimation of survival by traditional capture- recapture (CR) models designed for the study of residents only. Also, the study of transit is interesting in itself. We thus develop here a class of CR models to describe the presence of transients. In order to assess the merits of this approach we examme the bias of the traditional survival estimators in the presence of transients in relation to the power of different tests for detecting transients. We also compare the relative efficiency of an ad hoc approach to dealing with transients that leaves out the first observation of each animal. We then study a real example using lazuli bunting (Passerina amoena) and, in conclusion, discuss the design of an experiment aiming at the estimation of transience. In practice, the presence of transients is easily detected whenever the risk of bias is high. The ad hoc approach, which yields unbiased estimates for residents only, is satisfactory in a time-dependent context but poorly efficient when parameters are constant. The example shows that intermediate situations between strict 'residence' and strict 'transience' may exist in certain studies. Yet, most of the time, if the study design takes into account the expected length of stay of a transient, it should be possible to efficiently separate the two categories of animals.

  11. A structured approach for selecting carbon capture process models : A case study on monoethanolamine

    NARCIS (Netherlands)

    van der Spek, Mijndert; Ramirez, Andrea

    2014-01-01

    Carbon capture and storage is considered a promising option to mitigate CO2 emissions. This has resulted in many R&D efforts focusing at developing viable carbon capture technologies. During carbon capture technology development, process modeling plays an important role. Selecting an appropriate pro

  12. Shell model study of $^{40}$Ca muon capture and the $(0^+, 0)

    CERN Document Server

    Gorringe, T P

    2006-01-01

    We report results from shell model studies of muon capture on $^{40}$Ca to low-lying levels of $^{40}$K. We discuss the comparison between calculated capture rates, measured capture rates and analogous transitions in ($e$,$e^{\\prime}$) scattering in terms of the particle-hole structure of the $^{40}$Ca-$^{40}$K nuclei. We highlight the $^{40}$Ca$(0^+, 0)

  13. A structured approach for selecting carbon capture process models : A case study on monoethanolamine

    NARCIS (Netherlands)

    van der Spek, Mijndert; Ramirez, Andrea

    2014-01-01

    Carbon capture and storage is considered a promising option to mitigate CO2 emissions. This has resulted in many R&D efforts focusing at developing viable carbon capture technologies. During carbon capture technology development, process modeling plays an important role. Selecting an appropriate

  14. A structured approach for selecting carbon capture process models : A case study on monoethanolamine

    NARCIS (Netherlands)

    van der Spek, Mijndert; Ramirez, Andrea

    2014-01-01

    Carbon capture and storage is considered a promising option to mitigate CO2 emissions. This has resulted in many R&D efforts focusing at developing viable carbon capture technologies. During carbon capture technology development, process modeling plays an important role. Selecting an appropriate pro

  15. Modeling misidentification errors in capture-recapture studies using photographic identification of evolving marks

    Science.gov (United States)

    Yoshizaki, J.; Pollock, K.H.; Brownie, C.; Webster, R.A.

    2009-01-01

    Misidentification of animals is potentially important when naturally existing features (natural tags) are used to identify individual animals in a capture-recapture study. Photographic identification (photoID) typically uses photographic images of animals' naturally existing features as tags (photographic tags) and is subject to two main causes of identification errors: those related to quality of photographs (non-evolving natural tags) and those related to changes in natural marks (evolving natural tags). The conventional methods for analysis of capture-recapture data do not account for identification errors, and to do so requires a detailed understanding of the misidentification mechanism. Focusing on the situation where errors are due to evolving natural tags, we propose a misidentification mechanism and outline a framework for modeling the effect of misidentification in closed population studies. We introduce methods for estimating population size based on this model. Using a simulation study, we show that conventional estimators can seriously overestimate population size when errors due to misidentification are ignored, and that, in comparison, our new estimators have better properties except in cases with low capture probabilities (Society of America.

  16. Detailed microscopic calculation of stellar electron and positron capture rates on $^{24}$Mg for O+Ne+Mg core simulations

    CERN Document Server

    Nabi, Jameel-Un

    2014-01-01

    Few white dwarfs, located in binary systems, may acquire sufficiently high mass accretion rates resulting in the burning of carbon and oxygen under nondegenerate conditions forming a O+Ne+Mg core. These O+Ne+Mg cores are gravitationally less bound than more massive progenitor stars and can release more energy due to the nuclear burning. They are also amongst the probable candidates for low entropy r-process sites. Recent observations of subluminous Type II-P supernovae (e.g., 2005cs, 2003gd, 1999br, 1997D) were able to rekindle the interest in 8 -- 10 M$_{\\odot}$ which develop O+Ne+Mg cores. Microscopic calculations of capture rates on $^{24}$Mg, which may contribute significantly to the collapse of O+Ne+Mg cores, using shell model and proton-neutron quasiparticle random phase approximation (pn-QRPA) theory, were performed earlier and comparisons made. Simulators, however, may require these capture rates on a fine scale. For the first time a detailed microscopic calculation of the electron and positron captur...

  17. Delay modeling in logic simulation

    Energy Technology Data Exchange (ETDEWEB)

    Acken, J. M.; Goldstein, L. H.

    1980-01-01

    As digital integrated circuit size and complexity increases, the need for accurate and efficient computer simulation increases. Logic simulators such as SALOGS (SAndia LOGic Simulator), which utilize transition states in addition to the normal stable states, provide more accurate analysis than is possible with traditional logic simulators. Furthermore, the computational complexity of this analysis is far lower than that of circuit simulation such as SPICE. An eight-value logic simulation environment allows the use of accurate delay models that incorporate both element response and transition times. Thus, timing simulation with an accuracy approaching that of circuit simulation can be accomplished with an efficiency comparable to that of logic simulation. 4 figures.

  18. How does spatial study design influence density estimates from spatial capture-recapture models?

    Directory of Open Access Journals (Sweden)

    Rahel Sollmann

    Full Text Available When estimating population density from data collected on non-invasive detector arrays, recently developed spatial capture-recapture (SCR models present an advance over non-spatial models by accounting for individual movement. While these models should be more robust to changes in trapping designs, they have not been well tested. Here we investigate how the spatial arrangement and size of the trapping array influence parameter estimates for SCR models. We analysed black bear data collected with 123 hair snares with an SCR model accounting for differences in detection and movement between sexes and across the trapping occasions. To see how the size of the trap array and trap dispersion influence parameter estimates, we repeated analysis for data from subsets of traps: 50% chosen at random, 50% in the centre of the array and 20% in the South of the array. Additionally, we simulated and analysed data under a suite of trap designs and home range sizes. In the black bear study, we found that results were similar across trap arrays, except when only 20% of the array was used. Black bear density was approximately 10 individuals per 100 km(2. Our simulation study showed that SCR models performed well as long as the extent of the trap array was similar to or larger than the extent of individual movement during the study period, and movement was at least half the distance between traps. SCR models performed well across a range of spatial trap setups and animal movements. Contrary to non-spatial capture-recapture models, they do not require the trapping grid to cover an area several times the average home range of the studied species. This renders SCR models more appropriate for the study of wide-ranging mammals and more flexible to design studies targeting multiple species.

  19. Challenges of oxyfuel combustion modeling for carbon capture

    Science.gov (United States)

    Kangwanpongpan, T.; Klatt, M.; Krautz, H. J.

    2012-04-01

    From the policies scenario from Internal Energy Agency (IEA) in 2010, global energy demand for coal climbs from 26% in 2006 to 29% in 2030 and most of demands for coal comes from the power-generation sector [1]. According to the new Copenhagen protocol [3], Global CO2 emission is rising from power generation due to an increasing world demand of electricity. For Energy-related CO2 emission in 2009, 43% of CO2 emissions from fuel combustion were produced from coal, 37% from oil and 20% from gas [4]. Therefore, CO2 capture from coal is the key factor to reduce greenhouse gas emission. Oxyfuel combustion is one of the promising technologies for capturing CO2 from power plants and subsequent CO2 transportation and storage in a depleted oil or gas field or saline-aquifer. The concept of Oxyfuel combustion is to remove N2 from the combustion process and burn the fuel with a mixture composed of O2 and CO2 together with recycled flue gas back into combustion chamber in order to produce a flue gas consisting mainly of CO2. This flue gas can be easily purified, compressed and transported to storage sites. However, Oxyfuel plants are still in the phase of pilot-scaled projects [5] and combustion in Oxyfuel conditions must be further investigated for a scale-up plant. Computational fluid dynamics (CFD) serves as an efficient tool for many years in Oxyfuel combustion researches [6-12] to provide predictions of temperature, heat transfer, and product species from combustion process inside furnace. However, an insight into mathematical models for Oxyfuel combustion is still restricted due to many unknown parameters such as devolatilization rate, reaction mechanisms of volatile reactions, turbulent gaseous combustion of volatile products, char heterogeneous reactions, radiation properties of gaseous mixtures and heat transfer inside and through furnace's wall. Heat transfer drastically changes due to an increasing proportion of H2O and CO2 in these Oxyfuel conditions and the degree

  20. A bio-metal-organic framework for highly selective CO(2) capture: A molecular simulation study.

    Science.gov (United States)

    Chen, Yifei; Jiang, Jianwen

    2010-08-23

    A recently synthesized bio-metal-organic framework (bio-MOF-11) is investigated for CO(2) capture by molecular simulation. The adenine biomolecular linkers in bio-MOF-11 contain Lewis basic amino and pyrimidine groups as the preferential adsorption sites. The simulated and experimental adsorption isotherms of pure CO(2), H(2), and N(2) are in perfect agreement. Bio-MOF-11 exhibits larger adsorption capacities compared to numerous zeolites, activated carbons, and MOFs, which is attributed to the presence of multiple Lewis basic sites and nano-sized channels. The results for the adsorption of CO(2)/H(2) and CO(2)/N(2) mixtures in bio-MOF-11 show that CO(2) is more dominantly adsorbed than H(2) and N(2). With increasing pressure, the selectivity of CO(2)/H(2) initially increases owing to the strong interactions between CO(2) and the framework, and then decreases as a consequence of the entropy effect. However, the selectivity of CO(2)/N(2) monotonically increases with increasing pressure and finally reaches a constant. The selectivities in bio-MOF-11 are higher than in many nanoporous materials. The simulation results also reveal that a small amount of H(2)O has a negligible effect on the separation of CO(2)/H(2) and CO(2)/N(2) mixtures. The simulation study provides quantitative microscopic insight into the adsorption mechanism in bio-MOF-11 and suggests that bio-MOF-11 may be interesting for pre- and post-combustion CO(2) capture.

  1. Assessing the detail needed to capture rainfall-runoff dynamics with physics-based hydrologic response simulation

    Science.gov (United States)

    Mirus, B.B.; Ebel, B.A.; Heppner, C.S.; Loague, K.

    2011-01-01

    Concept development simulation with distributed, physics-based models provides a quantitative approach for investigating runoff generation processes across environmental conditions. Disparities within data sets employed to design and parameterize boundary value problems used in heuristic simulation inevitably introduce various levels of bias. The objective was to evaluate the impact of boundary value problem complexity on process representation for different runoff generation mechanisms. The comprehensive physics-based hydrologic response model InHM has been employed to generate base case simulations for four well-characterized catchments. The C3 and CB catchments are located within steep, forested environments dominated by subsurface stormflow; the TW and R5 catchments are located in gently sloping rangeland environments dominated by Dunne and Horton overland flows. Observational details are well captured within all four of the base case simulations, but the characterization of soil depth, permeability, rainfall intensity, and evapotranspiration differs for each. These differences are investigated through the conversion of each base case into a reduced case scenario, all sharing the same level of complexity. Evaluation of how individual boundary value problem characteristics impact simulated runoff generation processes is facilitated by quantitative analysis of integrated and distributed responses at high spatial and temporal resolution. Generally, the base case reduction causes moderate changes in discharge and runoff patterns, with the dominant process remaining unchanged. Moderate differences between the base and reduced cases highlight the importance of detailed field observations for parameterizing and evaluating physics-based models. Overall, similarities between the base and reduced cases indicate that the simpler boundary value problems may be useful for concept development simulation to investigate fundamental controls on the spectrum of runoff generation

  2. Preparations, models, and simulations.

    Science.gov (United States)

    Rheinberger, Hans-Jörg

    2015-01-01

    This paper proposes an outline for a typology of the different forms that scientific objects can take in the life sciences. The first section discusses preparations (or specimens)--a form of scientific object that accompanied the development of modern biology in different guises from the seventeenth century to the present: as anatomical-morphological specimens, as microscopic cuts, and as biochemical preparations. In the second section, the characteristics of models in biology are discussed. They became prominent from the end of the nineteenth century onwards. Some remarks on the role of simulations--characterising the life sciences of the turn from the twentieth to the twenty-first century--conclude the paper.

  3. Molecular Dynamics Simulations Capture the Misfolding of the Bovine Prion Protein at Acidic pH

    Directory of Open Access Journals (Sweden)

    Chin Jung Cheng

    2014-02-01

    Full Text Available Bovine spongiform encephalopathy (BSE, or mad cow disease, is a fatal neurodegenerative disease that is transmissible to humans and that is currently incurable. BSE is caused by the prion protein (PrP, which adopts two conformers; PrPC is the native innocuous form, which is α-helix rich; and PrPSc is the β-sheet rich misfolded form, which is infectious and forms neurotoxic species. Acidic pH induces the conversion of PrPC to PrPSc. We have performed molecular dynamics simulations of bovine PrP at various pH regimes. An acidic pH environment induced conformational changes that were not observed in neutral pH simulations. Putative misfolded structures, with nonnative β-strands formed in the flexible N-terminal domain, were found in acidic pH simulations. Two distinct pathways were observed for the formation of nonnative β-strands: at low pH, hydrophobic contacts with M129 nucleated the nonnative β-strand; at mid-pH, polar contacts involving Q168 and D178 facilitated the formation of a hairpin at the flexible N-terminus. These mid- and low pH simulations capture the process of nonnative β-strand formation, thereby improving our understanding of how PrPC misfolds into the β-sheet rich PrPSc and how pH factors into the process.

  4. TRANSFORM - TRANsient Simulation Framework of Reconfigurable Models

    Energy Technology Data Exchange (ETDEWEB)

    2017-09-01

    Existing development tools for early stage design and scoping of energy systems are often time consuming to use, proprietary, and do not contain the necessary function to model complete systems (i.e., controls, primary, and secondary systems) in a common platform. The Modelica programming language based TRANSFORM tool (1) provides a standardized, common simulation environment for early design of energy systems (i.e., power plants), (2) provides a library of baseline component modules to be assembled into full plant models using available geometry, design, and thermal-hydraulic data, (3) defines modeling conventions for interconnecting component models, and (4) establishes user interfaces and support tools to facilitate simulation development (i.e., configuration and parameterization), execution, and results display and capture.

  5. Simulation of dynamic magnetic particle capture and accumulation around a ferromagnetic wire

    Science.gov (United States)

    Choomphon-anomakhun, Natthaphon; Ebner, Armin D.; Natenapit, Mayuree; Ritter, James A.

    2017-04-01

    A new approach for modeling high gradient magnetic separation (HGMS)-type systems during the time-dependent capture and accumulation of magnetic particles by a ferromagnetic wire was developed. This new approach assumes the fluid (slurry) viscosity, comprised of water and magnetic particles, is a function of the magnetic particle concentration in the fluid, with imposed maxima on both the particle concentration and fluid viscosity to avoid unrealistic limits. In 2-D, the unsteady-state Navier-Stokes equations for compressible fluid flow and the unsteady-state continuity equations applied separately to the water and magnetic particle phases in the slurry were solved simultaneously, along with the Laplace equations for the magnetic potential applied separately to the slurry and wire, to evaluate the velocities and concentrations around the wire in a narrow channel using COMSOL Multiphysics. The results from this model revealed very realistic magnetically attractive and repulsive zones forming in time around the wire. These collection zones formed their own impermeable viscous phase during accumulation that was also magnetic with its area and magnetism impacting locally both the fluid flow and magnetic fields around the wire. These collection zones increased with an increase in the applied magnetic field. For a given set of conditions, the capture ability peaked and then decreased to zero at infinite time during magnetic particle accumulation in the collection zones. Predictions of the collection efficiency from a steady-state, clean collector, trajectory model could not show this behavior; it also agreed only qualitatively with the dynamic model and then only at the early stages of collection and more so at a higher applied magnetic field. Also, the collection zones decreased in size when the accumulation regions included magnetic particle magnetization (realistic) compared to when they excluded it (unrealistic). Overall, this might be the first time a mathematical

  6. A multicriteria decision analysis model and risk assessment framework for carbon capture and storage.

    Science.gov (United States)

    Humphries Choptiany, John Michael; Pelot, Ronald

    2014-09-01

    Multicriteria decision analysis (MCDA) has been applied to various energy problems to incorporate a variety of qualitative and quantitative criteria, usually spanning environmental, social, engineering, and economic fields. MCDA and associated methods such as life-cycle assessments and cost-benefit analysis can also include risk analysis to address uncertainties in criteria estimates. One technology now being assessed to help mitigate climate change is carbon capture and storage (CCS). CCS is a new process that captures CO2 emissions from fossil-fueled power plants and injects them into geological reservoirs for storage. It presents a unique challenge to decisionmakers (DMs) due to its technical complexity, range of environmental, social, and economic impacts, variety of stakeholders, and long time spans. The authors have developed a risk assessment model using a MCDA approach for CCS decisions such as selecting between CO2 storage locations and choosing among different mitigation actions for reducing risks. The model includes uncertainty measures for several factors, utility curve representations of all variables, Monte Carlo simulation, and sensitivity analysis. This article uses a CCS scenario example to demonstrate the development and application of the model based on data derived from published articles and publicly available sources. The model allows high-level DMs to better understand project risks and the tradeoffs inherent in modern, complex energy decisions.

  7. Process capture and modeling via workflow for integrated human-based automated command and control processes

    Science.gov (United States)

    Green, David; Dunaway, Brad; Reaper, Jerome

    2005-05-01

    The Virtual Testbed for Advanced Command and Control Concepts (VTAC) program is performing research and development efforts leading to the creation of a testbed for new Command and Control (C2) processes, subprocesses and embedded automated systems and subsystems. This testbed will initially support the capture and modeling of existing C2 processes/subprocesses. Having modeled these at proper levels of abstraction, proposed revisions or replacements to processes, systems and subsystems can be evaluated within a virtual workspace that integrates human operators and automated systems in the context of a larger C2 process. By utilizing such a testbed early in the development cycle, expected improvements resulting from specific revisions or replacements can be quantitatively established. Crossover effects resulting from changes to one or more interrelated processes can also be measured. Quantified measures of improvement can then be provided to decision makers for use in cost-to-performance benefits analysis prior to implementing proposed revisions, replacements, or a sequence of planned enhancements. This paper first presents a high-level view of the VTAC project, followed by a discussion of an example C2 process that was captured, abstracted, and modeled. The abstraction approach, model implementation, and simulations results are covered in detail.

  8. Laboratory simulation of intact capture of cometary and asteroidal dust particles in ISAS

    Science.gov (United States)

    Fujiwara, A.; Nakamura, A.; Kadono, T.

    In order to develop a collector for intact capturing of cometary dust particles in the SOCCER mission and regolith dust particles released from asteroid surfaces by the impact of projectiles launched from a flying-by spacecraft, various kinds of materials as the collector candidates have been exposed to hypervelocity projectiles in our laboratory. Data based on the penetration characteristics of various materials (penetration depth, hole profile, effectiveness for intact capturing) are greatly increased. The materials tested for these simulation experiments include various kinds of low-density media and multisheet stacks; these are foamed plastics (polystyrene 0.01 g/cc), silica aerogels (0.04 g/cc), air (0.001 g/cc), liquid, and multisheet stack consisting of thin Al sheets (thickness 0.002 to 0.1 mm) or polyethylene sheets. Projectiles used are spheres or cylinders of nylon, polycarbonate, basalt, copper, iron, and volatile organics (e.g.,paradichlorobenzene) of size ranging from 30 micrometers to 1 cm launched by a two-stage light gas gun and a rail gun in ISAS at velocity up to about 7 km/s. Some results obtained by using nylon projectiles of velocity less than about 5 km/s are presented; the penetration depth vs. bulk density of the collector material for several kinds of materials and the velocity at which the projectiles begin to fragment vs. material density for foamed polystyrene.

  9. Analog design and simulation using OrCAD capture and PSpice

    CERN Document Server

    Fitzpatrick, Dennis

    2012-01-01

    Anyone involved in circuit design that needs the practical know-how it takes to design a successful circuit or product, will find this practical guide to using Capture-PSpice (written by a former Cadence PSpice expert for Europe) an essential book. The text delivers step-by-step guidance on using Capture-PSpice to help professionals produce reliable, effective designs. Readers will learn how to get up and running quickly and efficiently with industry standard software and in sufficient detail to enable building upon personal experience to avoid common errors and pit-falls. This book is of great benefit to professional electronics design engineers, advanced amateur electronics designers, electronic engineering students and academic staff looking for a book with a real-world design outlook. This book provides both a comprehensive user guide, and a detailed overview of simulation; each chapter has worked and ready to try sample designs and provides a wide range of to-do exercises; core skills are developed using...

  10. Design and Simulation of Photoneutron Source by MCNPX Monte Carlo Code for Boron Neutron Capture Therapy

    Directory of Open Access Journals (Sweden)

    Mona Zolfaghari

    2015-07-01

    Full Text Available Introduction Electron linear accelerator (LINAC can be used for neutron production in Boron Neutron Capture Therapy (BNCT. BNCT is an external radiotherapeutic method for the treatment of some cancers. In this study, Varian 2300 C/D LINAC was simulated as an electron accelerator-based photoneutron source to provide a suitable neutron flux for BNCT. Materials and Methods Photoneutron sources were simulated, using MCNPX Monte Carlo code. In this study, a 20 MeV LINAC was utilized for electron-photon reactions. After the evaluation of cross-sections and threshold energies, lead (Pb, uranium (U and beryllium deuteride (BeD2were selected as photoneutron sources. Results According to the simulation results, optimized photoneutron sources with a compact volume and photoneutron yields of 107, 108 and 109 (n.cm-2.s-1 were obtained for Pb, U and BeD2 composites. Also, photoneutrons increased by using enriched U (10-60% as an electron accelerator-based photoneutron source. Conclusion Optimized photoneutron sources were obtained with compact sizes of 107, 108 and 109 (n.cm-2.s-1, respectively. These fluxs can be applied for BNCT by decelerating fast neutrons and using a suitable beam-shaping assembly, surrounding electron-photon and photoneutron sources.

  11. Design and Simulation of Photoneutron Source by MCNPX Monte Carlo Code for Boron Neutron Capture Therapy

    Directory of Open Access Journals (Sweden)

    Mona Zolfaghari

    2015-07-01

    Full Text Available Introduction Electron linear accelerator (LINAC can be used for neutron production in Boron Neutron Capture Therapy (BNCT. BNCT is an external radiotherapeutic method for the treatment of some cancers. In this study, Varian 2300 C/D LINAC was simulated as an electron accelerator-based photoneutron source to provide a suitable neutron flux for BNCT. Materials and Methods Photoneutron sources were simulated, using MCNPX Monte Carlo code. In this study, a 20 MeV LINAC was utilized for electron-photon reactions. After the evaluation of cross-sections and threshold energies, lead (Pb, uranium (U and beryllium deuteride (BeD2were selected as photoneutron sources. Results According to the simulation results, optimized photoneutron sources with a compact volume and photoneutron yields of 107, 108 and 109 (n.cm-2.s-1 were obtained for Pb, U and BeD2 composites. Also, photoneutrons increased by using enriched U (10-60% as an electron accelerator-based photoneutron source. Conclusion Optimized photoneutron sources were obtained with compact sizes of 107, 108 and 109 (n.cm-2.s-1, respectively. These fluxs can be applied for BNCT by decelerating fast neutrons and using a suitable beam-shaping assembly, surrounding electron-photon and photoneutron sources.

  12. Coupled-Channel Models of Direct-Semidirect Capture via Giant-Dipole Resonances

    Energy Technology Data Exchange (ETDEWEB)

    Thompson, I J [Lawrence Livermore National Laboratory (LLNL); Escher, Jutta E [ORNL; Arbanas, Goran [ORNL

    2013-01-01

    Semidirect capture, a two-step process that excites a giant-dipole resonance followed by its radiative de-excitation, is a dominant process near giant-dipole resonances, that is, for incoming neutron energies within 5 20 MeV. At lower energies such processes may affect neutron capture rates that are relevant to astrophysical nucleosynthesis models. We implement a semidirect capture model in the coupled-channel reaction code Fresco and validate it by comparing the cross section for direct-semidirect capture 208Pb(n,g)209Pb to experimental data. We also investigate the effect of low-energy electric dipole strength in the pygmy resonance. We use a conventional single-particle direct-semidirect capture code Cupido for comparison. Furthermore, we present and discuss our results for direct-semidirect capture reaction 130Sn(n,g)131Sn, the cross section of which is known to have a significant effect on nucleosynthesis models.

  13. Development of a dynamic simulator for a natural gas combined cycle (NGCC) power plant with post-combustion carbon capture

    Energy Technology Data Exchange (ETDEWEB)

    Liese, E.; Zitney, S.

    2012-01-01

    The AVESTAR Center located at the U.S. Department of Energy’s National Energy Technology Laboratory and West Virginia University is a world-class research and training environment dedicated to using dynamic process simulation as a tool for advancing the safe, efficient and reliable operation of clean energy plants with CO{sub 2} capture. The AVESTAR Center was launched with a high-fidelity dynamic simulator for an Integrated Gasification Combined Cycle (IGCC) power plant with pre-combustion carbon capture. The IGCC dynamic simulator offers full-scope Operator Training Simulator (OTS) Human Machine Interface (HMI) graphics for realistic, real-time control room operation and is integrated with a 3D virtual Immersive Training Simulator (ITS), thus allowing joint control room and field operator training. The IGCC OTS/ITS solution combines a “gasification with CO{sub 2} capture” process simulator with a “combined cycle” power simulator into a single high-performance dynamic simulation framework. This presentation will describe progress on the development of a natural gas combined cycle (NGCC) dynamic simulator based on the syngas-fired combined cycle portion of AVESTAR’s IGCC dynamic simulator. The 574 MW gross NGCC power plant design consisting of two advanced F-class gas turbines, two heat recovery steam generators (HRSGs), and a steam turbine in a multi-shaft 2x2x1 configuration will be reviewed. Plans for integrating a post-combustion carbon capture system will also be discussed.

  14. A log-linear multidimensional Rasch model for capture-recapture.

    Science.gov (United States)

    Pelle, E; Hessen, D J; van der Heijden, P G M

    2016-02-20

    In this paper, a log-linear multidimensional Rasch model is proposed for capture-recapture analysis of registration data. In the model, heterogeneity of capture probabilities is taken into account, and registrations are viewed as dichotomously scored indicators of one or more latent variables that can account for correlations among registrations. It is shown how the probability of a generic capture profile is expressed under the log-linear multidimensional Rasch model and how the parameters of the traditional log-linear model are derived from those of the log-linear multidimensional Rasch model. Finally, an application of the model to neural tube defects data is presented.

  15. Capturing optically important constituents and properties in a marine biogeochemical and ecosystem model

    Science.gov (United States)

    Dutkiewicz, S.; Hickman, A. E.; Jahn, O.; Gregg, W. W.; Mouw, C. B.; Follows, M. J.

    2015-02-01

    We present a numerical model of the ocean that couples a three-stream radiative transfer component with a marine biogeochemical-ecosystem in a dynamic three-dimensional physical framework. The radiative transfer component resolves spectral irradiance as it is absorbed and scattered within the water column. We explicitly include the effect of several optically important water constituents (the phytoplankton community, detrital particles, and coloured dissolved organic matter, CDOM). The model is evaluated against in situ observed and satellite derived products. In particular we compare to concurrently measured biogeochemical, ecosystem and optical data along a north-south transect of the Atlantic Ocean. The simulation captures the patterns and magnitudes of these data, and estimates surface upwelling irradiance analogous to that observed by ocean colour satellite instruments. We conduct a series of sensitivity experiments to demonstrate, globally, the relative importance of each of the water constituents, and the crucial feedbacks between the light field and the relative fitness of phytoplankton types, and the biogeochemistry of the ocean. CDOM has proportionally more importance at short wavelengths and in more productive waters, phytoplankton absorption is especially important at the deep chlorophyll a (Chl a) maximum, and absorption by water molecules is relatively most important in the highly oligotrophic gyres. Sensitivity experiments in which absorption by any of the optical constituents was increased led to a decrease in the size of the oligotrophic regions of the subtropical gyres: lateral nutrient supplies were enhanced as a result of decreasing high latitude productivity. Scattering does not as strongly affect the ecosystem and biogeochemistry fields within the water column but is important for setting the surface upwelling irradiance, and hence sea surface reflectance. Having a model capable of capturing bio-optical feedbacks will be important for

  16. Simulation of capture algorithms of GPS signal by Matlab/Simulink%GPS信号捕获算法Matlab/Simulink仿真

    Institute of Scientific and Technical Information of China (English)

    夏运兵; 龚文斌; 姜泉江; 姜兴龙

    2015-01-01

    为了评价GPS信号并行码相位捕获算法、并行频率捕获算法、线性捕获算法3种常见捕获算法捕获性能的优劣,采用Matlab/Simulink工具对其捕获效果进行仿真分析。首先理论分析三种捕获算法的优劣,再用Simulink模拟信号源,M文件实现捕获过程的方式,并以捕获时间作为标准,得出并行码相位捕获所用时间最短,并行频率捕获时间相对较长,线性捕获最慢的结果。这些算法的仿真实现和捕获性能的比较,对接收终端捕获模块的研发工作具有一定的参考与指导作用。%In order to evaluate the capture performance of GPS signal parallel code phase acquisition algorithm, parallel frequency acquisition algorithm, linear acquisition algorithm, this paper simulates these three algorithms by using Matlab/Simulink. First, this paper analyses the merits of these three kinds of capturing algorithm theoretically, then simulates a signal source by Simulink, realizes the capture process by M file. Using the capture time as the standard, paper can get the conclusion that the capture time of parallel code phase is the shortest one, parallel frequency capture is second, linear capture is the slowest algorithm. The simulate implementation of these algorithms and the comparison of capture performance have some reference and guidance on the receiving terminal capture module development work.

  17. Notes on modeling and simulation

    Energy Technology Data Exchange (ETDEWEB)

    Redondo, Antonio [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

    2017-03-10

    These notes present a high-level overview of how modeling and simulation are carried out by practitioners. The discussion is of a general nature; no specific techniques are examined but the activities associated with all modeling and simulation approaches are briefly addressed. There is also a discussion of validation and verification and, at the end, a section on why modeling and simulation are useful.

  18. Capturing Vegetation Diversity in the Ent Terrestrial Biosphere Model

    Science.gov (United States)

    Kiang, N. Y.; Haralick, R. M.; Cook, B.; Aleinov, I. D.

    2013-12-01

    We present preliminary results from data mining to develop parameter sets and global vegetation structure datasets to set boundary conditions for the Ent Terrestrial Biosphere Model (Ent TBM) for improved representation of diversity and to propagate uncertainty in simulations of land carbon dynamics in the 20th century and under future climate change. The Ent TBM is the only dynamic global vegetation model (DGVM) developed for coupling with general circulation models (GCMs) to account for the height structure of mixed canopies, including a canopy radiative transfer scheme that accounts for foliage clumping in dynamically changing canopies. It is flexibly programmed to incorporate any number of "plant functional types" (PFTs). It is now a coupled component of the ModelE2 version of the NASA Goddard Institute for Space Studies (GISS) general circulation model (GCM). We demonstrate a data mining method, linear manifold clustering, to be used with several very recently compiled large databases of plant traits and phenology combined with climate and satellite data, to identify new PFT groupings, and also conduct customized parameter fits of PFT traits already defined in Ent. These parameter sets are used together with satellite-derived global forest height structure and land cover derived from a combination of satellite and inventory sources and bioclimatic relations to provide a new estimate and uncertainty bounds on vegetation biomass carbon stocks. These parameter sets will also be used to reproduce atmospheric CO2 time series over the flask observational period, to evaluate the impact of improved representation of vegetation dynamics on soil carbon stocks, and finally to produce a projection of the land carbon sink under future climate change. This research is timely in taking advantage of new, globally ranging vegetation databases, satellite-derived forest heights, and the advanced framework of the Ent TBM. It will advance understanding of and reduce uncertainty in

  19. A Simulation Model for Evaluating Distributed Systems Dependability

    CERN Document Server

    Dobre, Ciprian; Cristea, Valentin

    2012-01-01

    In this paper we present a new simulation model designed to evaluate the dependability in distributed systems. This model extends the MONARC simulation model with new capabilities for capturing reliability, safety, availability, security, and maintainability requirements. The model has been implemented as an extension of the multithreaded, process oriented simulator MONARC, which allows the realistic simulation of a wide-range of distributed system technologies, with respect to their specific components and characteristics. The extended simulation model includes the necessary components to inject various failure events, and provides the mechanisms to evaluate different strategies for replication, redundancy procedures, and security enforcement mechanisms, as well. The results obtained in simulation experiments presented in this paper probe that the use of discrete-event simulators, such as MONARC, in the design and development of distributed systems is appealing due to their efficiency and scalability.

  20. Carbon Capture Multidisciplinary Simulation Center Trilab Support Team (TST) Fall Meeting 2016 Report

    Energy Technology Data Exchange (ETDEWEB)

    Draeger, Erik W. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)

    2017-01-03

    The theme of this year’s meeting was “Predictivity: Now and in the Future”. After welcoming remarks, Erik Draeger gave a talk on the NNSA Labs’ history of predictive simulation and the new challenges faced by upcoming architecture changes. He described an example where the volume of analysis data produced by a set of inertial confinement fusion (ICF) simulations on the Trinity machine was too large to store or transfer, and the steps needed to reduce it to a manageable size. He also described the software re-engineering plan for LLNL’s suite of multiphysics codes and physics packages with a new push toward common components, making collaboration with teams like the CCMSC who already have experience trying to architect complex multiphysics code infrastructure on next-generation architectures all the more important. Phil Smith then gave an overview outlining the goals of the project, namely to accelerate development of new technology in the form of high efficiency carbon capture pulverized coal power generation as well as further optimize existing state of the art designs. He then presented a summary of the Center’s top-down uncertainty quantification approach, in which ultimate target predictivity informs uncertainty targets for lower-level components, and gave data on how close all the different components currently are to their targets. Most components still need an approximately two-fold reduction in uncertainty to hit the ultimate predictivity target, but the current accuracy is already rather impressive.

  1. Simple stochastic dynamical models capturing the statistical diversity of El Niño Southern Oscillation

    Science.gov (United States)

    Chen, Nan; Majda, Andrew J.

    2017-01-01

    The El Niño Southern Oscillation (ENSO) has significant impact on global climate and seasonal prediction. A simple modeling framework is developed here that automatically captures the statistical diversity of ENSO. First, a stochastic parameterization of the wind bursts including both westerly and easterly winds is coupled to a simple ocean–atmosphere model that is otherwise deterministic, linear, and stable. Second, a simple nonlinear zonal advection with no ad hoc parameterization of the background sea-surface temperature (SST) gradient and a mean easterly trade wind anomaly representing the multidecadal acceleration of the trade wind are both incorporated into the coupled model that enables anomalous warm SST in the central Pacific. Then a three-state stochastic Markov jump process is used to drive the wind burst activity that depends on the strength of the western Pacific warm pool in a simple and effective fashion. It allows the coupled model to simulate the quasi-regular moderate traditional El Niño, the super El Niño, and the central Pacific (CP) El Niño as well as the La Niña with realistic features. In addition to the anomalous SST, the Walker circulation anomalies at different ENSO phases all resemble those in nature. In particular, the coupled model succeeds in reproducing the observed episode during the 1990s, where a series of 5-y CP El Niños is followed by a super El Niño and then a La Niña. Importantly, both the variance and the non-Gaussian statistical features in different Niño regions spanning from the western to the eastern Pacific are captured by the coupled model. PMID:28137886

  2. Evaluating uncertainty in simulation models

    Energy Technology Data Exchange (ETDEWEB)

    McKay, M.D.; Beckman, R.J.; Morrison, J.D.; Upton, S.C.

    1998-12-01

    The authors discussed some directions for research and development of methods for assessing simulation variability, input uncertainty, and structural model uncertainty. Variance-based measures of importance for input and simulation variables arise naturally when using the quadratic loss function of the difference between the full model prediction y and the restricted prediction {tilde y}. The concluded that generic methods for assessing structural model uncertainty do not now exist. However, methods to analyze structural uncertainty for particular classes of models, like discrete event simulation models, may be attainable.

  3. Simulation Model of a Transient

    DEFF Research Database (Denmark)

    Jauch, Clemens; Sørensen, Poul; Bak-Jensen, Birgitte

    2005-01-01

    This paper describes the simulation model of a controller that enables an active-stall wind turbine to ride through transient faults. The simulated wind turbine is connected to a simple model of a power system. Certain fault scenarios are specified and the turbine shall be able to sustain operation...... in case of such faults. The design of the controller is described and its performance assessed by simulations. The control strategies are explained and the behaviour of the turbine discussed....

  4. Simulation Model of a Transient

    DEFF Research Database (Denmark)

    Jauch, Clemens; Sørensen, Poul; Bak-Jensen, Birgitte

    2005-01-01

    This paper describes the simulation model of a controller that enables an active-stall wind turbine to ride through transient faults. The simulated wind turbine is connected to a simple model of a power system. Certain fault scenarios are specified and the turbine shall be able to sustain operation...

  5. Molecular Simulation on Microstructure of Ionic Liquids in Capture of CO2

    Institute of Scientific and Technical Information of China (English)

    YUE Zhen-uo; LIU Xiao-min; ZHAO Yu-ling; ZHANG Xiao-chun; LU Xing-mei; ZHANG Suo-jiang

    2011-01-01

    Molecular dynamic simulation is used to study the microstructure of four kinds of ionic liquids (ILs),[Emim]PF6,[Emim][Tf2N],[PC6,6,6,14]PF6 and [PC6,6,6,14][Tf2N] in the capture process of CO2.Radial distribution function (RDF) and spatial distribution function (SDF) are used to analyze the microscopic properties of these systems.The calculated results show that the space distribution of CO2 around ILs determines the capability of ionic liquids for capturing CO2.Based on the analysis of SDF,CO2 and PF6- are overlapped partially around [Emim]+ in [Emim]PF6-CO2 mixture.When the anion is [Tf2N]-,cations are mainly distributed on one side of [Tf2N]- near N atom,and CO2 is concentrated on two sides near the fluoroalkylgroup (-CF3),and there is little overlapped district between cation and CO2.In [PC6,6,6,14]PF6-CO2 mixture,layered structure is found and CO2 is much nearer to PF6- than [PC6,6,6,14]+.Based on the analysis of RDF,in the phosphonium-based ILs,the highest distribution densities of anions and CO2 around cations are about 6 and 3 times as their average ones respectively,while in the imidazolium-based ILs,they are about 3 and 2 respectively,this means that the distributions of CO2 and anions around the imidazolium-based ILs are more evenly distributed than those around the phosphonium-bascd ILs.

  6. Semivarying coefficient models for capture-recapture data: colony size estimation for the little penguin Eudyptula minor.

    Science.gov (United States)

    Stoklosa, Jakub; Dann, Peter; Huggins, Richard

    2014-09-01

    To accommodate seasonal effects that change from year to year into models for the size of an open population we consider a time-varying coefficient model. We fit this model to a capture-recapture data set collected on the little penguin Eudyptula minor in south-eastern Australia over a 25 year period using Jolly-Seber type estimators and nonparametric P-spline techniques. The time-varying coefficient model identified strong changes in the seasonal pattern across the years which we further examined using functional data analysis techniques. To evaluate the methodology we also conducted several simulation studies that incorporate seasonal variation.

  7. Examining Temporal Sample Scale and Model Choice with Spatial Capture-Recapture Models in the Common Leopard Panthera pardus.

    Science.gov (United States)

    Goldberg, Joshua F; Tempa, Tshering; Norbu, Nawang; Hebblewhite, Mark; Mills, L Scott; Wangchuk, Tshewang R; Lukacs, Paul

    2015-01-01

    Many large carnivores occupy a wide geographic distribution, and face threats from habitat loss and fragmentation, poaching, prey depletion, and human wildlife-conflicts. Conservation requires robust techniques for estimating population densities and trends, but the elusive nature and low densities of many large carnivores make them difficult to detect. Spatial capture-recapture (SCR) models provide a means for handling imperfect detectability, while linking population estimates to individual movement patterns to provide more accurate estimates than standard approaches. Within this framework, we investigate the effect of different sample interval lengths on density estimates, using simulations and a common leopard (Panthera pardus) model system. We apply Bayesian SCR methods to 89 simulated datasets and camera-trapping data from 22 leopards captured 82 times during winter 2010-2011 in Royal Manas National Park, Bhutan. We show that sample interval length from daily, weekly, monthly or quarterly periods did not appreciably affect median abundance or density, but did influence precision. We observed the largest gains in precision when moving from quarterly to shorter intervals. We therefore recommend daily sampling intervals for monitoring rare or elusive species where practicable, but note that monthly or quarterly sample periods can have similar informative value. We further develop a novel application of Bayes factors to select models where multiple ecological factors are integrated into density estimation. Our simulations demonstrate that these methods can help identify the "true" explanatory mechanisms underlying the data. Using this method, we found strong evidence for sex-specific movement distributions in leopards, suggesting that sexual patterns of space-use influence density. This model estimated a density of 10.0 leopards/100 km2 (95% credibility interval: 6.25-15.93), comparable to contemporary estimates in Asia. These SCR methods provide a guide to

  8. Simple dynamical models capturing the key features of the Central Pacific El Niño.

    Science.gov (United States)

    Chen, Nan; Majda, Andrew J

    2016-10-18

    The Central Pacific El Niño (CP El Niño) has been frequently observed in recent decades. The phenomenon is characterized by an anomalous warm sea surface temperature (SST) confined to the central Pacific and has different teleconnections from the traditional El Niño. Here, simple models are developed and shown to capture the key mechanisms of the CP El Niño. The starting model involves coupled atmosphere-ocean processes that are deterministic, linear, and stable. Then, systematic strategies are developed for incorporating several major mechanisms of the CP El Niño into the coupled system. First, simple nonlinear zonal advection with no ad hoc parameterization of the background SST gradient is introduced that creates coupled nonlinear advective modes of the SST. Secondly, due to the recent multidecadal strengthening of the easterly trade wind, a stochastic parameterization of the wind bursts including a mean easterly trade wind anomaly is coupled to the simple atmosphere-ocean processes. Effective stochastic noise in the wind burst model facilitates the intermittent occurrence of the CP El Niño with realistic amplitude and duration. In addition to the anomalous warm SST in the central Pacific, other major features of the CP El Niño such as the rising branch of the anomalous Walker circulation being shifted to the central Pacific and the eastern Pacific cooling with a shallow thermocline are all captured by this simple coupled model. Importantly, the coupled model succeeds in simulating a series of CP El Niño that lasts for 5 y, which resembles the two CP El Niño episodes during 1990-1995 and 2002-2006.

  9. Digital Simulation Research on Tree Dynamic Feature Capturing Information System Based on Image Processing

    Directory of Open Access Journals (Sweden)

    Lin Hong

    2016-09-01

    Full Text Available This paper establishes tree model based on L system, and builds the wind field mathematical model added noise disturbance; focusing on the leaves dancing in the branches with the wind and leaves fall in motion; and it avoids the occurrence of the penetration phenomena in the leaf movement process because of using bounding sphere method in combination with the convex polyhedron detection method for collision detection. The whole system is developed by VC++ 6.0 environment combined with OpenGL tool, the simulation process is real and natural, which can meet the requirements of real-time. The proposed algorithm is applied to the leaves motion simulation when wind speed is not too large, the wind model should be improved for the more detailed research in the future, considering the condition of the branch breaking caused by wind speed and the complexity of the tree model structure.

  10. Simulation - modeling - experiment; Simulation - modelisation - experience

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2004-07-01

    After two workshops held in 2001 on the same topics, and in order to make a status of the advances in the domain of simulation and measurements, the main goals proposed for this workshop are: the presentation of the state-of-the-art of tools, methods and experiments in the domains of interest of the Gedepeon research group, the exchange of information about the possibilities of use of computer codes and facilities, about the understanding of physical and chemical phenomena, and about development and experiment needs. This document gathers 18 presentations (slides) among the 19 given at this workshop and dealing with: the deterministic and stochastic codes in reactor physics (Rimpault G.); MURE: an evolution code coupled with MCNP (Meplan O.); neutronic calculation of future reactors at EdF (Lecarpentier D.); advance status of the MCNP/TRIO-U neutronic/thermal-hydraulics coupling (Nuttin A.); the FLICA4/TRIPOLI4 thermal-hydraulics/neutronics coupling (Aniel S.); methods of disturbances and sensitivity analysis of nuclear data in reactor physics, application to VENUS-2 experimental reactor (Bidaud A.); modeling for the reliability improvement of an ADS accelerator (Biarotte J.L.); residual gas compensation of the space charge of intense beams (Ben Ismail A.); experimental determination and numerical modeling of phase equilibrium diagrams of interest in nuclear applications (Gachon J.C.); modeling of irradiation effects (Barbu A.); elastic limit and irradiation damage in Fe-Cr alloys: simulation and experiment (Pontikis V.); experimental measurements of spallation residues, comparison with Monte-Carlo simulation codes (Fallot M.); the spallation target-reactor coupling (Rimpault G.); tools and data (Grouiller J.P.); models in high energy transport codes: status and perspective (Leray S.); other ways of investigation for spallation (Audoin L.); neutrons and light particles production at intermediate energies (20-200 MeV) with iron, lead and uranium targets (Le Colley F

  11. Thermodynamic simulation of CO{sub 2} capture for an IGCC power plant using the calcium looping cycle

    Energy Technology Data Exchange (ETDEWEB)

    Li, Y. [National Engineering Laboratory for Coal-Burning Pollutant Emission Reduction, Shandong University, Jinan (China); Zhao, C.; Ren, Q. [School of Energy and Environment, Southeast University, Nanjing (China)

    2011-06-15

    A CO{sub 2} capture process for an integrated gasification combined cycle (IGCC) power plant using the calcium looping cycle was proposed. The CO{sub 2} capture process using natural and modified limestone was simulated and investigated with the software package Aspen Plus. It incorporated a fresh feed of sorbent to compensate for the decay in CO{sub 2} capture activity during long-term cycles. The sorbent flow ratios have significant effect on the CO{sub 2} capture efficiency and net efficiency of the CO{sub 2} capture system. The IGCC power plant, using the modified limestone, exhibits higher CO{sub 2} capture efficiency than that using the natural limestone at the same sorbent flow ratios. The system net efficiency using the natural and modified limestones achieves 41.7% and 43.1%, respectively, at the CO{sub 2} capture efficiency of 90% without the effect of sulfation. (Copyright copyright 2011 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  12. IVOA Recommendation: Simulation Data Model

    CERN Document Server

    Lemson, Gerard; Cervino, Miguel; Gheller, Claudio; Gray, Norman; LePetit, Franck; Louys, Mireille; Ooghe, Benjamin; Wagner, Rick; Wozniak, Herve

    2014-01-01

    In this document and the accompanying documents we describe a data model (Simulation Data Model) describing numerical computer simulations of astrophysical systems. The primary goal of this standard is to support discovery of simulations by describing those aspects of them that scientists might wish to query on, i.e. it is a model for meta-data describing simulations. This document does not propose a protocol for using this model. IVOA protocols are being developed and are supposed to use the model, either in its original form or in a form derived from the model proposed here, but more suited to the particular protocol. The SimDM has been developed in the IVOA Theory Interest Group with assistance of representatives of relevant working groups, in particular DM and Semantics.

  13. Amine modeling for CO2 capture: internals selection.

    Science.gov (United States)

    Karpe, Prakash; Aichele, Clint P

    2013-04-16

    Traditionally, trays have been the mass-transfer device of choice in amine absorption units. However, the need to process large volumes of flue gas to capture CO2 and the resultant high costs of multiple trains of large trayed columns have prompted process licensors and vendors to investigate alternative mass-transfer devices. These alternatives include third-generation random packings and structured packings. Nevertheless, clear-cut guidelines for selection of packings for amine units are lacking. This paper provides well-defined guidelines and a consistent framework for the choice of mass-transfer devices for amine absorbers and regenerators. This work emphasizes the role played by the flow parameter, a measure of column liquid loading and pressure, in the type of packing selected. In addition, this paper demonstrates the significant economic advantage of packings over trays in terms of capital costs (CAPEX) and operating costs (OPEX).

  14. Investigation of Isfahan miniature neutron source reactor (MNSR for boron neutron capture therapy by MCNP simulation

    Directory of Open Access Journals (Sweden)

    S.Z Kalantari

    2015-01-01

    Full Text Available One of the important neutron sources for Boron Neutron Capture Therapy (BNCT is a nuclear reactor. It needs a high flux of epithermal neutrons. The optimum conditions of the neutron spectra for BNCT are provided by the International Atomic Energy Agency (IAEA. In this paper, Miniature Neutron Source Reactor (MNSR as a neutron source for BNCT was investigated. For this purpose, we designed a Beam Shaping Assembly (BSA for the reactor and the neutron transport from the core of the reactor to the output windows of BSA was simulated by MCNPX code. To optimize the BSA performance, two sets of parameters should be evaluated, in-air and in-phantom parameters. For evaluating in-phantom parameters, a Snyder head phantom was used and biological dose rate and dose-depth curve were calculated in brain normal and tumor tissues. Our calculations showed that the neutron flux of the MNSR reactor can be used for BNCT, and the designed BSA in optimum conditions had a good therapeutic characteristic for BNCT.

  15. Indoor simulations reveal differences among plant species in capturing particulate matter.

    Science.gov (United States)

    Chen, Jungang; Yu, Xinxiao; Bi, Huaxing; Fu, Yanlin

    2017-01-01

    A number of studies have focused on the capacity of urban trees and shrubs to serve as efficient biological filters to mitigate air pollution. In this study, five different tree species were assessed for this function. Kerria japonica, Sophora japonica, Philadelphus pekinensis, Gleditsia sinensis, and Prunus persica 'Atropurpurea' were tested in a deposition chamber using (NH4)2SO4 particles. We quantified and compared the capability of all tested trees to remove particles by assessing deposition velocity, a measure of the ability to remove particles. When placed in the deposition chamber, S. japonica had the greatest deposition velocity, followed by Philadelphus pekinensis, G. sinensis, Prunus persica 'Atropurpurea,' and K. japonica, in descending order. In addition, the comparison of deposition velocities among these species suggested that certain leaf geometries and surface characteristics of broadleaf trees, such as trichomes and grooves, increased particle capture. However, these results change under a different simulation condition using ambient air, suggesting that some trees actually increase pollutant number concentrations more than reduce particle concentration. This outcome can be explained by the aerodynamic effect of trees exceeding the filtering capacity of vegetation under some conditions. This highlights the difficulty of generalizing species selection criteria for practice use. Accordingly, our results indicate that using vegetation to reduce particle pollution and improve the air quality is not a universally advisable and viable solution.

  16. MeV Neutron Production from Thermal Neutron Capture in {6}^Li Simulated with Geant4

    CERN Document Server

    Santoro, Valentina; Bentley, Phillip M

    2015-01-01

    Various Li compounds are commonly used at neutron facilities as neutron absorbers. These compounds provide one of the highest ratios of neutron attenuation to $\\gamma$-ray production. Unfortunately, the usage of these compounds can also give rise to fast neutron emission with energies up to almost 16 MeV. Historically, some details in this fast neutron production mechanism can be absent from some modeling packages under some optimization scenarios. In this work, we tested Geant4 to assess the performance of this simulation toolkit for the fast neutron generation mechanism. We compare the results of simulations performed with Geant4 to available measurements. The outcome of our study shows that results of the Geant4 simulations are in good agreement with the available measurements for $^6$Li fast neutron production, and suitable for neutron instrument background evaluation at spallation neutron sources.

  17. MeV Neutron Production from Thermal Neutron Capture in 6Li Simulated With Geant4

    Science.gov (United States)

    Santoro, Valentina; DiJulio, Douglas D.; Bentley, Phillip M.

    2016-09-01

    Various Li compounds are commonly used at neutron facilities as neutron absorbers. These compounds provide one of the highest ratios of neutron attenuation to y- ray production. Unfortunately, the usage of these compounds can also give rise to fast neutron emission with energies up to almost 16 MeV. Historically, some details in this fast neutron production mechanism can be absent from some modeling packages under some optimization scenarios. In this work, we tested Geant4 to assess the performance of this simulation toolkit for the fast neutron generation mechanism. We compare the results of simulations performed with Geant4 to available measurements. The outcome of our study shows that results of the Geant4 simulations are in good agreement with the available measurements for 6 Li fast neutron production, and suitable for neutron instrument background evaluation at spallation neutron sources.

  18. Modeling and Simulation with INS.

    Science.gov (United States)

    Roberts, Stephen D.; And Others

    INS, the Integrated Network Simulation language, puts simulation modeling into a network framework and automatically performs such programming activities as placing the problem into a next event structure, coding events, collecting statistics, monitoring status, and formatting reports. To do this, INS provides a set of symbols (nodes and branches)…

  19. Simulation modeling of estuarine ecosystems

    Science.gov (United States)

    Johnson, R. W.

    1980-01-01

    A simulation model has been developed of Galveston Bay, Texas ecosystem. Secondary productivity measured by harvestable species (such as shrimp and fish) is evaluated in terms of man-related and controllable factors, such as quantity and quality of inlet fresh-water and pollutants. This simulation model used information from an existing physical parameters model as well as pertinent biological measurements obtained by conventional sampling techniques. Predicted results from the model compared favorably with those from comparable investigations. In addition, this paper will discuss remotely sensed and conventional measurements in the framework of prospective models that may be used to study estuarine processes and ecosystem productivity.

  20. MODFLOW-NWT model of a hypothetical stream-aquifer system to assess capture map bias

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — A MODFLOW-NWT (version 1.0.9) model of a hypothetical stream-aquifer system is presented for the evaluation and characterization of capture map bias. The...

  1. Towards Automatic Processing of Virtual City Models for Simulations

    Science.gov (United States)

    Piepereit, R.; Schilling, A.; Alam, N.; Wewetzer, M.; Pries, M.; Coors, V.

    2016-10-01

    Especially in the field of numerical simulations, such as flow and acoustic simulations, the interest in using virtual 3D models to optimize urban systems is increasing. The few instances in which simulations were already carried out in practice have been associated with an extremely high manual and therefore uneconomical effort for the processing of models. Using different ways of capturing models in Geographic Information System (GIS) and Computer Aided Engineering (CAE), increases the already very high complexity of the processing. To obtain virtual 3D models suitable for simulation, we developed a tool for automatic processing with the goal to establish ties between the world of GIS and CAE. In this paper we introduce a way to use Coons surfaces for the automatic processing of building models in LoD2, and investigate ways to simplify LoD3 models in order to reduce unnecessary information for a numerical simulation.

  2. A testable gravitational capture model for the origin of the Earth's Moon

    Science.gov (United States)

    Malcuit, R. J.; Winters, R. R.; Mickelson, M. E.

    1984-01-01

    A gravitational capture model is proposed to explain lunar evolution. The model is divided into five orbital eras. In the first era, it is postulated that the pre-capture Moon formed as a small planetary unit on the inner edge of the Asteroid Zone. Orbital era 2 commenced when the Moon's orbit became Earth-crossing. As the Moon underwent periodic gravitational encounters with Earth in a near Earth orbit (orbital era 3), the lunar body because warmer and thus more easily capture. Era 4 saw the Moon inserted into a geocentric orbit that gradually became more circular. Following orbital circulation, the lunar orbit gradually expanded to its present dimensions (era 5).

  3. Modeling and Simulating Environmental Effects

    OpenAIRE

    Guest, Peter S.; Murphree, Tom; Frederickson, Paul A.; Guest, Arlene A.

    2012-01-01

    MOVES Research & Education Systems Seminar: Presentation; Session 4: Collaborative NWDC/NPS M&S Research; Moderator: Curtis Blais; Modeling and Simulating Environmental Effects; speakers: Peter Guest, Paul Frederickson & Tom Murphree Environmental Effects Group

  4. TREAT Modeling and Simulation Strategy

    Energy Technology Data Exchange (ETDEWEB)

    DeHart, Mark David [Idaho National Lab. (INL), Idaho Falls, ID (United States)

    2015-09-01

    This report summarizes a four-phase process used to describe the strategy in developing modeling and simulation software for the Transient Reactor Test Facility. The four phases of this research and development task are identified as (1) full core transient calculations with feedback, (2) experiment modeling, (3) full core plus experiment simulation and (4) quality assurance. The document describes the four phases, the relationship between these research phases, and anticipated needs within each phase.

  5. Simple capture-recapture models permitting unequal catchability and variable sampling effort.

    Science.gov (United States)

    Agresti, A

    1994-06-01

    We consider two capture-recapture models that imply that the logit of the probability of capture is an additive function of an animal catchability parameter and a parameter reflecting the sampling effort. The models are special cases of the Rasch model, and satisfy the property of quasi-symmetry. One model is log-linear and the other is a latent class model. For the log-linear model, point and interval estimates of the population size are easily obtained using standard software, such as GLIM.

  6. Reconstructing 3D Tree Models Using Motion Capture and Particle Flow

    Directory of Open Access Journals (Sweden)

    Jie Long

    2013-01-01

    Full Text Available Recovering tree shape from motion capture data is a first step toward efficient and accurate animation of trees in wind using motion capture data. Existing algorithms for generating models of tree branching structures for image synthesis in computer graphics are not adapted to the unique data set provided by motion capture. We present a method for tree shape reconstruction using particle flow on input data obtained from a passive optical motion capture system. Initial branch tip positions are estimated from averaged and smoothed motion capture data. Branch tips, as particles, are also generated within a bounding space defined by a stack of bounding boxes or a convex hull. The particle flow, starting at branch tips within the bounding volume under forces, creates tree branches. The forces are composed of gravity, internal force, and external force. The resulting shapes are realistic and similar to the original tree crown shape. Several tunable parameters provide control over branch shape and arrangement.

  7. The mind in the model: capturing expert knowledge with the help of fuzzy logic

    NARCIS (Netherlands)

    Janssen, J.A.E.B.; Schielen, R.M.J.; Augustijn, D.C.M.; Os, van A.G.

    2006-01-01

    Fuzzy logic offers a way of capturing qualitative knowledge in models. We tested its application in modelling for long term river management planning. We used fuzzy logic to model landscape impacts of different river measures. Preliminary results show that the method allows for modelling expert know

  8. Stochastic modeling analysis and simulation

    CERN Document Server

    Nelson, Barry L

    1995-01-01

    A coherent introduction to the techniques for modeling dynamic stochastic systems, this volume also offers a guide to the mathematical, numerical, and simulation tools of systems analysis. Suitable for advanced undergraduates and graduate-level industrial engineers and management science majors, it proposes modeling systems in terms of their simulation, regardless of whether simulation is employed for analysis. Beginning with a view of the conditions that permit a mathematical-numerical analysis, the text explores Poisson and renewal processes, Markov chains in discrete and continuous time, se

  9. Capturing optically important constituents and properties in a marine biogeochemical and ecosystem model

    Science.gov (United States)

    Dutkiewicz, S.; Hickman, A. E.; Jahn, O.; Gregg, W. W.; Mouw, C. B.; Follows, M. J.

    2015-07-01

    We present a numerical model of the ocean that couples a three-stream radiative transfer component with a marine biogeochemical-ecosystem component in a dynamic three-dimensional physical framework. The radiative transfer component resolves the penetration of spectral irradiance as it is absorbed and scattered within the water column. We explicitly include the effect of several optically important water constituents (different phytoplankton functional types; detrital particles; and coloured dissolved organic matter, CDOM). The model is evaluated against in situ-observed and satellite-derived products. In particular we compare to concurrently measured biogeochemical, ecosystem, and optical data along a meridional transect of the Atlantic Ocean. The simulation captures the patterns and magnitudes of these data, and estimates surface upwelling irradiance analogous to that observed by ocean colour satellite instruments. We find that incorporating the different optically important constituents explicitly and including spectral irradiance was crucial to capture the variability in the depth of the subsurface chlorophyll a (Chl a) maximum. We conduct a series of sensitivity experiments to demonstrate, globally, the relative importance of each of the water constituents, as well as the crucial feedbacks between the light field, the relative fitness of phytoplankton types, and the biogeochemistry of the ocean. CDOM has proportionally more importance at attenuating light at short wavelengths and in more productive waters, phytoplankton absorption is relatively more important at the subsurface Chl a maximum, and water molecules have the greatest contribution when concentrations of other constituents are low, such as in the oligotrophic gyres. Scattering had less effect on attenuation, but since it is important for the amount and type of upwelling irradiance, it is crucial for setting sea surface reflectance. Strikingly, sensitivity experiments in which absorption by any of the

  10. Model reduction for circuit simulation

    CERN Document Server

    Hinze, Michael; Maten, E Jan W Ter

    2011-01-01

    Simulation based on mathematical models plays a major role in computer aided design of integrated circuits (ICs). Decreasing structure sizes, increasing packing densities and driving frequencies require the use of refined mathematical models, and to take into account secondary, parasitic effects. This leads to very high dimensional problems which nowadays require simulation times too large for the short time-to-market demands in industry. Modern Model Order Reduction (MOR) techniques present a way out of this dilemma in providing surrogate models which keep the main characteristics of the devi

  11. Program SPACECAP: software for estimating animal density using spatially explicit capture-recapture models

    Science.gov (United States)

    Gopalaswamy, Arjun M.; Royle, J. Andrew; Hines, James E.; Singh, Pallavi; Jathanna, Devcharan; Kumar, N. Samba; Karanth, K. Ullas

    2012-01-01

    1. The advent of spatially explicit capture-recapture models is changing the way ecologists analyse capture-recapture data. However, the advantages offered by these new models are not fully exploited because they can be difficult to implement. 2. To address this need, we developed a user-friendly software package, created within the R programming environment, called SPACECAP. This package implements Bayesian spatially explicit hierarchical models to analyse spatial capture-recapture data. 3. Given that a large number of field biologists prefer software with graphical user interfaces for analysing their data, SPACECAP is particularly useful as a tool to increase the adoption of Bayesian spatially explicit capture-recapture methods in practice.

  12. AVESTAR Center: Dynamic simulation-based collaboration toward achieving opertional excellence for IGCC plants with crbon capture

    Energy Technology Data Exchange (ETDEWEB)

    Zitney, Strphen E. [U.S. DOE; Liese, Eric A. [U.S. DOE; Mahapatra, Priyadarshi [URS; Turton, Richard [WVU; Bhattacharyya, Debangsu [WVU; Provost, Graham [Fossil Consulting Services

    2012-01-01

    To address challenges in attaining operational excellence for clean energy plants, the National Energy Technology Laboratory has launched a world-class facility for Advanced Virtual Energy Simulation Training And Research (AVESTAR(TM)). The AVESTAR Center brings together state-of-the-art, real-time, high-fidelity dynamic simulators with operator training systems and 3D virtual immersive training systems into an integrated energy plant and control room environment. This paper will highlight the AVESTAR Center simulators, facilities, and comprehensive training, education, and research programs focused on the operation and control of an integrated gasification combined cycle power plant (IGCC) with carbon dioxide capture.

  13. Capturing the spectrum of interaction effects in genetic association studies by simulated evaporative cooling network analysis.

    Directory of Open Access Journals (Sweden)

    Brett A McKinney

    2009-03-01

    Full Text Available Evidence from human genetic studies of several disorders suggests that interactions between alleles at multiple genes play an important role in influencing phenotypic expression. Analytical methods for identifying Mendelian disease genes are not appropriate when applied to common multigenic diseases, because such methods investigate association with the phenotype only one genetic locus at a time. New strategies are needed that can capture the spectrum of genetic effects, from Mendelian to multifactorial epistasis. Random Forests (RF and Relief-F are two powerful machine-learning methods that have been studied as filters for genetic case-control data due to their ability to account for the context of alleles at multiple genes when scoring the relevance of individual genetic variants to the phenotype. However, when variants interact strongly, the independence assumption of RF in the tree node-splitting criterion leads to diminished importance scores for relevant variants. Relief-F, on the other hand, was designed to detect strong interactions but is sensitive to large backgrounds of variants that are irrelevant to classification of the phenotype, which is an acute problem in genome-wide association studies. To overcome the weaknesses of these data mining approaches, we develop Evaporative Cooling (EC feature selection, a flexible machine learning method that can integrate multiple importance scores while removing irrelevant genetic variants. To characterize detailed interactions, we construct a genetic-association interaction network (GAIN, whose edges quantify the synergy between variants with respect to the phenotype. We use simulation analysis to show that EC is able to identify a wide range of interaction effects in genetic association data. We apply the EC filter to a smallpox vaccine cohort study of single nucleotide polymorphisms (SNPs and infer a GAIN for a collection of SNPs associated with adverse events. Our results suggest an important

  14. Dynamics modeling and simulation of flexible airships

    Science.gov (United States)

    Li, Yuwen

    The resurgence of airships has created a need for dynamics models and simulation capabilities of these lighter-than-air vehicles. The focus of this thesis is a theoretical framework that integrates the flight dynamics, structural dynamics, aerostatics and aerodynamics of flexible airships. The study begins with a dynamics model based on a rigid-body assumption. A comprehensive computation of aerodynamic effects is presented, where the aerodynamic forces and moments are categorized into various terms based on different physical effects. A series of prediction approaches for different aerodynamic effects are unified and applied to airships. The numerical results of aerodynamic derivatives and the simulated responses to control surface deflection inputs are verified by comparing to existing wind-tunnel and flight test data. With the validated aerodynamics and rigid-body modeling, the equations of motion of an elastic airship are derived by the Lagrangian formulation. The airship is modeled as a free-free Euler-Bernoulli beam and the bending deformations are represented by shape functions chosen as the free-free normal modes. In order to capture the coupling between the aerodynamic forces and the structural elasticity, local velocity on the deformed vehicle is used in the computation of aerodynamic forces. Finally, with the inertial, gravity, aerostatic and control forces incorporated, the dynamics model of a flexible airship is represented by a single set of nonlinear ordinary differential equations. The proposed model is implemented as a dynamics simulation program to analyze the dynamics characteristics of the Skyship-500 airship. Simulation results are presented to demonstrate the influence of structural deformation on the aerodynamic forces and the dynamics behavior of the airship. The nonlinear equations of motion are linearized numerically for the purpose of frequency domain analysis and for aeroelastic stability analysis. The results from the latter for the

  15. Absorber Model for CO2 Capture by Monoethanolamine

    DEFF Research Database (Denmark)

    Faramarzi, Leila; Kontogeorgis, Georgios; Michelsen, Michael Locht

    2010-01-01

    The rate-based steady-state model proposed by Gabrielsen et al. (Gabrielsen, J.; Michelsen, M. L.; Kontogeorgis, G. M.; Stenby, E. H. AIChE J. 2006, 52, 10, 3443-3451) for the design of the CO2-2-amino-2-methylpropanol absorbers is adopted and improved for the design of the CO2-monoethanolamine...... absorber. The influence of the application of different mass transfer correlations on the model's performance is investigated. Analytical expressions for the calculation of the enhancement factor for the second order as well as the pseudo-first-order reaction regime are integrated in the model......, and their impact on the model's prediction is compared. The model has been successfully applied to CO2 absorber packed columns and validated against pilot plant data with good agreement....

  16. VISION: Verifiable Fuel Cycle Simulation Model

    Energy Technology Data Exchange (ETDEWEB)

    Jacob J. Jacobson; Abdellatif M. Yacout; Gretchen E. Matthern; Steven J. Piet; David E. Shropshire

    2009-04-01

    The nuclear fuel cycle is a very complex system that includes considerable dynamic complexity as well as detail complexity. In the nuclear power realm, there are experts and considerable research and development in nuclear fuel development, separations technology, reactor physics and waste management. What is lacking is an overall understanding of the entire nuclear fuel cycle and how the deployment of new fuel cycle technologies affects the overall performance of the fuel cycle. The Advanced Fuel Cycle Initiative’s systems analysis group is developing a dynamic simulation model, VISION, to capture the relationships, timing and delays in and among the fuel cycle components to help develop an understanding of how the overall fuel cycle works and can transition as technologies are changed. This paper is an overview of the philosophy and development strategy behind VISION. The paper includes some descriptions of the model and some examples of how to use VISION.

  17. Modelled three-dimensional suction accuracy predicts prey capture success in three species of centrarchid fishes

    Science.gov (United States)

    Kane, Emily A.; Higham, Timothy E.

    2014-01-01

    Prey capture is critical for survival, and differences in correctly positioning and timing a strike (accuracy) are likely related to variation in capture success. However, an ability to quantify accuracy under natural conditions, particularly for fishes, is lacking. We developed a predictive model of suction hydrodynamics and applied it to natural behaviours using three-dimensional kinematics of three centrarchid fishes capturing evasive and non-evasive prey. A spheroid ingested volume of water (IVW) with dimensions predicted by peak gape and ram speed was verified with known hydrodynamics for two species. Differences in capture success occurred primarily with evasive prey (64–96% success). Micropterus salmoides had the greatest ram and gape when capturing evasive prey, resulting in the largest and most elongate IVW. Accuracy predicted capture success, although other factors may also be important. The lower accuracy previously observed in M. salmoides was not replicated, but this is likely due to more natural conditions in our study. Additionally, we discuss the role of modulation and integrated behaviours in shaping the IVW and determining accuracy. With our model, accuracy is a more accessible performance measure for suction-feeding fishes, which can be used to explore macroevolutionary patterns of prey capture evolution. PMID:24718455

  18. The use of mixed logit models to reflect heterogeneity in capture-recapture studies.

    Science.gov (United States)

    Coull, B A; Agresti, A

    1999-03-01

    We examine issues in estimating population size N with capture-recapture models when there is variable catchability among subjects. We focus on a logistic-normal mixed model, for which the logit of the probability of capture is an additive function of a random subject and a fixed sampling occasion parameter. When the probability of capture is small or the degree of heterogeneity is large, the log-likelihood surface is relatively flat and it is difficult to obtain much information about N. We also discuss a latent class model and a log-linear model that account for heterogeneity and show that the log-linear model has greater scope. Models assuming homogeneity provide much narrower intervals for N but are usually highly overly optimistic, the actual coverage probability being much lower than the nominal level.

  19. A model capturing novel strand symmetries in bacterial DNA

    Energy Technology Data Exchange (ETDEWEB)

    Sobottka, Marcelo, E-mail: sobottka@mtm.ufsc.br [Departamento de Matematica, Universidade Federal de Santa Catarina (Brazil); Hart, Andrew G., E-mail: ahart@dim.uchile.cl [Departamento de Ingenieria Matematica and Centro de Modelamiento Matematico, Universidad de Chile (Chile)

    2011-07-15

    Highlights: {yields} We propose a simple stochastic model to construct primitive DNA sequences. {yields} The model provide an explanation for Chargaff's second parity rule in primitive DNA sequences. {yields} The model is also used to predict a novel type of strand symmetry in primitive DNA sequences. {yields} We extend the results for bacterial DNA sequences and compare distributional properties intrinsic to the model to statistical estimates from 1049 bacterial genomes. {yields} We find out statistical evidences that the novel type of strand symmetry holds for bacterial DNA sequences. -- Abstract: Chargaff's second parity rule for short oligonucleotides states that the frequency of any short nucleotide sequence on a strand is approximately equal to the frequency of its reverse complement on the same strand. Recent studies have shown that, with the exception of organellar DNA, this parity rule generally holds for double-stranded DNA genomes and fails to hold for single-stranded genomes. While Chargaff's first parity rule is fully explained by the Watson-Crick pairing in the DNA double helix, a definitive explanation for the second parity rule has not yet been determined. In this work, we propose a model based on a hidden Markov process for approximating the distributional structure of primitive DNA sequences. Then, we use the model to provide another possible theoretical explanation for Chargaff's second parity rule, and to predict novel distributional aspects of bacterial DNA sequences.

  20. A VRLA battery simulation model

    Energy Technology Data Exchange (ETDEWEB)

    Pascoe, P.E.; Anbuky, A.H. [Invensys Energy Systems NZ Limited, Christchurch (New Zealand)

    2004-05-01

    A valve regulated lead acid (VRLA) battery simulation model is an invaluable tool for the standby power system engineer. The obvious use for such a model is to allow the assessment of battery performance. This may involve determining the influence of cells suffering from state of health (SOH) degradation on the performance of the entire string, or the running of test scenarios to ascertain the most suitable battery size for the application. In addition, it enables the engineer to assess the performance of the overall power system. This includes, for example, running test scenarios to determine the benefits of various load shedding schemes. It also allows the assessment of other power system components, either for determining their requirements and/or vulnerabilities. Finally, a VRLA battery simulation model is vital as a stand alone tool for educational purposes. Despite the fundamentals of the VRLA battery having been established for over 100 years, its operating behaviour is often poorly understood. An accurate simulation model enables the engineer to gain a better understanding of VRLA battery behaviour. A system level multipurpose VRLA battery simulation model is presented. It allows an arbitrary battery (capacity, SOH, number of cells and number of strings) to be simulated under arbitrary operating conditions (discharge rate, ambient temperature, end voltage, charge rate and initial state of charge). The model accurately reflects the VRLA battery discharge and recharge behaviour. This includes the complex start of discharge region known as the coup de fouet. (author)

  1. Modelling and Simulation: An Overview

    NARCIS (Netherlands)

    M.J. McAleer (Michael); F. Chan (Felix); L. Oxley (Les)

    2013-01-01

    textabstractThe papers in this special issue of Mathematics and Computers in Simulation cover the following topics: improving judgmental adjustment of model-based forecasts, whether forecast updates are progressive, on a constrained mixture vector autoregressive model, whether all estimators are bor

  2. General introduction to simulation models

    DEFF Research Database (Denmark)

    Hisham Beshara Halasa, Tariq; Boklund, Anette

    2012-01-01

    Monte Carlo simulation can be defined as a representation of real life systems to gain insight into their functions and to investigate the effects of alternative conditions or actions on the modeled system. Models are a simplification of a system. Most often, it is best to use experiments and field...

  3. Modelling, simulating and optimizing Boilers

    DEFF Research Database (Denmark)

    Sørensen, Kim; Condra, Thomas Joseph; Houbak, Niels

    2003-01-01

    of the boiler has been developed and simulations carried out by means of the Matlab integration routines. The model is prepared as a dynamic model consisting of both ordinary differential equations and algebraic equations, together formulated as a Differential-Algebraic- Equation system. Being able to operate...

  4. Calculation of Evaluation Variables for High Gradient Magnetic Separation with an Idealized Capture Model

    CERN Document Server

    Xu, Fengyu

    2016-01-01

    This paper regards feed mine as a mixture of intergrowths and pure non-magnetic mineral particles, presents a method to calculate the evaluation variables such as grade and recovery in high gradient magnetic separation (HGMS). A idealized capture model is constructed in which the interaction between particles is not taken into account and only for the initial aggregation condition that the separator has the highest capture efficiency. In the model we adopt the functions that use nominal particle radius and magnetic mineral content as independent variables to describe volume fraction distribution and capture efficiency of intergrowths respectively. Through adding multi-wire magnetic fields and setting periodic boundary conditions in flow field analysis, we modify the computational domain of the single-wire capture theory to a element domain that periodically appears in the multi-wire matrix. By means of finite element software, particle trajectories, flow field and magnetic field are clearly exhibited, and the...

  5. Evaluating Alternative Methodologies for Capturing As-Built Building Information Models (BIM) For Existing Facilities

    Science.gov (United States)

    2010-08-01

    units Generators Boilers Chillers Fire alarm display panels Sprinkler valves Fire hose connections Exhaust fans Telephone panels Switchgear...captured for each component. Once all data is captured for the space, the system would automatically move on to the next space. Furthermore, all...Information Modeling (BIM) systems . The Army Corps of Engineers requires the use of BIM on all new construction projects associated with the Army

  6. Capturing RNA Folding Free Energy with Coarse-Grained Molecular Dynamics Simulations

    Science.gov (United States)

    Bell, David R.; Cheng, Sara Y.; Salazar, Heber; Ren, Pengyu

    2017-01-01

    We introduce a coarse-grained RNA model for molecular dynamics simulations, RACER (RnA CoarsE-gRained). RACER achieves accurate native structure prediction for a number of RNAs (average RMSD of 2.93 Å) and the sequence-specific variation of free energy is in excellent agreement with experimentally measured stabilities (R2 = 0.93). Using RACER, we identified hydrogen-bonding (or base pairing), base stacking, and electrostatic interactions as essential driving forces for RNA folding. Also, we found that separating pairing vs. stacking interactions allowed RACER to distinguish folded vs. unfolded states. In RACER, base pairing and stacking interactions each provide an approximate stability of 3–4 kcal/mol for an A-form helix. RACER was developed based on PDB structural statistics and experimental thermodynamic data. In contrast with previous work, RACER implements a novel effective vdW potential energy function, which led us to re-parameterize hydrogen bond and electrostatic potential energy functions. Further, RACER is validated and optimized using a simulated annealing protocol to generate potential energy vs. RMSD landscapes. Finally, RACER is tested using extensive equilibrium pulling simulations (0.86 ms total) on eleven RNA sequences (hairpins and duplexes). PMID:28393861

  7. Capturing socio-technical systems with agent-based modelling

    NARCIS (Netherlands)

    Van Dam, K.H.

    2009-01-01

    What is a suitable modelling approach for socio-technical systems? The answer to this question is of great importance to decision makers in large scale interconnected network systems. The behaviour of these systems is determined by many actors, situated in a dynamic, multi-actor, multi-objective and

  8. Capturing socio-technical systems with agent-based modelling

    NARCIS (Netherlands)

    Van Dam, K.H.

    2009-01-01

    What is a suitable modelling approach for socio-technical systems? The answer to this question is of great importance to decision makers in large scale interconnected network systems. The behaviour of these systems is determined by many actors, situated in a dynamic, multi-actor, multi-objective and

  9. Modelling of catalytic oxidation of NH3 and reduction of NO on limestone during sulphur capture

    DEFF Research Database (Denmark)

    Kiil, Søren; Bhatia, Suresh K.; Dam-Johansen, Kim

    1996-01-01

    for the catalytic chemistry of NH3 during simultaneous sulphur capture on a Stevns Chalk particle. The reduction of NO by NH3 over CaSO4 (which is the product of the reaction between SO2, O2 and limestone) was found to be important because this reaction could explain the change in selectivity with increased solid...... conversion observed experimentally. Simulations also suggested that it may be advantageous with respect to the emission of NO to use smallinstead of big limestone particles for desulphurisation in fluidised bed combustors due to the ways different sized particles capture SO2....

  10. Dynamics of Postcombustion CO2 Capture Plants: Modeling, Validation, and Case Study.

    Science.gov (United States)

    van de Haar, Adam; Trapp, Carsten; Wellner, Kai; de Kler, Robert; Schmitz, Gerhard; Colonna, Piero

    2017-02-22

    The capture of CO2 from power plant flue gases provides an opportunity to mitigate emissions that are harmful to the global climate. While the process of CO2 capture using an aqueous amine solution is well-known from experience in other technical sectors (e.g., acid gas removal in the gas processing industry), its operation combined with a power plant still needs investigation because in this case, the interaction with power plants that are increasingly operated dynamically poses control challenges. This article presents the dynamic modeling of CO2 capture plants followed by a detailed validation using transient measurements recorded from the pilot plant operated at the Maasvlakte power station in the Netherlands. The model predictions are in good agreement with the experimental data related to the transient changes of the main process variables such as flow rate, CO2 concentrations, temperatures, and solvent loading. The validated model was used to study the effects of fast power plant transients on the capture plant operation. A relevant result of this work is that an integrated CO2 capture plant might enable more dynamic operation of retrofitted fossil fuel power plants because the large amount of steam needed by the capture process can be diverted rapidly to and from the power plant.

  11. A minimal physical model captures the shapes of crawling cells

    Science.gov (United States)

    Tjhung, E.; Tiribocchi, A.; Marenduzzo, D.; Cates, M. E.

    2015-01-01

    Cell motility in higher organisms (eukaryotes) is crucial to biological functions ranging from wound healing to immune response, and also implicated in diseases such as cancer. For cells crawling on hard surfaces, significant insights into motility have been gained from experiments replicating such motion in vitro. Such experiments show that crawling uses a combination of actin treadmilling (polymerization), which pushes the front of a cell forward, and myosin-induced stress (contractility), which retracts the rear. Here we present a simplified physical model of a crawling cell, consisting of a droplet of active polar fluid with contractility throughout, but treadmilling connected to a thin layer near the supporting wall. The model shows a variety of shapes and/or motility regimes, some closely resembling cases seen experimentally. Our work strongly supports the view that cellular motility exploits autonomous physical mechanisms whose operation does not need continuous regulatory effort.

  12. Capturing Multivariate Spatial Dependence: Model, Estimate and then Predict

    OpenAIRE

    Cressie, Noel; Burden, Sandy; Davis, Walter; Krivitsky, Pavel N.; Mokhtarian, Payam; Suesse, Thomas; Zammit-Mangion, Andrew

    2015-01-01

    Physical processes rarely occur in isolation, rather they influence and interact with one another. Thus, there is great benefit in modeling potential dependence between both spatial locations and different processes. It is the interaction between these two dependencies that is the focus of Genton and Kleiber's paper under discussion. We see the problem of ensuring that any multivariate spatial covariance matrix is nonnegative definite as important, but we also see it as a means to an end. Tha...

  13. A Complete Transport Validated Model on a Zeolite Membrane for Carbon Dioxide Permeance and Capture

    CERN Document Server

    Gkanas, Evangelos I; Stubos, Athanasios K; Makridis, Sofoklis S

    2013-01-01

    The CO2 emissions from major industries cause serious global environment problems and their mitigation is urgently needed. The use of zeolite membranes is a very efficient way in order to capture CO2 from some flue gases. The dominant transport mechanism at low temperature andor high pressure is the diffusion through the membrane. This procedure can be divided in three steps: Adsorption of the molecules of the species in the surface of the membrane, then a driving force gives a path where the species follow inside the membrane and finally the species desorbed from the surface of the membrane. The current work is aimed at developing a simulation model for the CO2 transport through a zeolite membrane and estimate the diffusion phenomenon through a very thin membrane of 150 nm in a Wicke-Kallenbach cell. The cell is cylindrical in shape with diameter of 19 mm and consists of a retentate gas chamber, a permeate gas chamber which are separated by a cylindrical zeolite membrane. This apparatus have been modeled wit...

  14. Vehicle dynamics modeling and simulation

    CERN Document Server

    Schramm, Dieter; Bardini, Roberto

    2014-01-01

    The authors examine in detail the fundamentals and mathematical descriptions of the dynamics of automobiles. In this context different levels of complexity will be presented, starting with basic single-track models up to complex three-dimensional multi-body models. A particular focus is on the process of establishing mathematical models on the basis of real cars and the validation of simulation results. The methods presented are explained in detail by means of selected application scenarios.

  15. Analysis of model sensitivity and predictive uncertainty of capture zones in the Espanola Basin regional aquifer, Northern New Mexico

    Energy Technology Data Exchange (ETDEWEB)

    Vesselinov, V. V. (Velimir V.); Keating, E. H. (Elizabeth H.); Zyvoloski, G. A. (George Anthony)

    2002-01-01

    Predictions and their uncertainty are key aspects of any modeling effort. The prediction uncertainty can be significant when the predictions depend on uncertain system parameters. We analyze prediction uncertainties through constrained nonlinear second-order optimization of an inverse model. The optimized objective function is the weighted squared-difference between observed and simulated system quantities (flux and time-dependent head data). The constraints are defined by the maximization/minimization of the prediction within a given objective-function range. The method is applied in capture-zone analyses of groundwater-supply systems using a three-dimensional numerical model of the Espanola Basin aquifer. We use the finite-element simulator FEHM coupled with parameter-estimation/predictive-analysis code PEST. The model is run in parallel on a multi-processor supercomputer. We estimate sensitivity and uncertainty of model predictions such as capture-zone identification and travel times. While the methodology is extremely powerful, it is numerically intensive.

  16. Stochastic models: theory and simulation.

    Energy Technology Data Exchange (ETDEWEB)

    Field, Richard V., Jr.

    2008-03-01

    Many problems in applied science and engineering involve physical phenomena that behave randomly in time and/or space. Examples are diverse and include turbulent flow over an aircraft wing, Earth climatology, material microstructure, and the financial markets. Mathematical models for these random phenomena are referred to as stochastic processes and/or random fields, and Monte Carlo simulation is the only general-purpose tool for solving problems of this type. The use of Monte Carlo simulation requires methods and algorithms to generate samples of the appropriate stochastic model; these samples then become inputs and/or boundary conditions to established deterministic simulation codes. While numerous algorithms and tools currently exist to generate samples of simple random variables and vectors, no cohesive simulation tool yet exists for generating samples of stochastic processes and/or random fields. There are two objectives of this report. First, we provide some theoretical background on stochastic processes and random fields that can be used to model phenomena that are random in space and/or time. Second, we provide simple algorithms that can be used to generate independent samples of general stochastic models. The theory and simulation of random variables and vectors is also reviewed for completeness.

  17. Computational Modeling of Simulation Tests.

    Science.gov (United States)

    1980-06-01

    Mexico , March 1979. 14. Kinney, G. F.,.::. IeiN, .hoce 1h Ir, McMillan, p. 57, 1962. 15. Courant and Friedrichs, ,U: r. on moca an.: Jho...AD 79 275 NEW MEXICO UNIV ALBUGUERGUE ERIC H WANG CIVIL ENGINE-ETC F/6 18/3 COMPUTATIONAL MODELING OF SIMULATION TESTS.(U) JUN 80 6 LEIGH, W CHOWN, B...COMPUTATIONAL MODELING OF SIMULATION TESTS00 0G. Leigh W. Chown B. Harrison Eric H. Wang Civil Engineering Research Facility University of New Mexico

  18. Particle Capture Efficiency in a Multi-Wire Model for High Gradient Magnetic Separation

    CERN Document Server

    Eisenträger, Almut; Griffiths, Ian M

    2014-01-01

    High gradient magnetic separation (HGMS) is an efficient way to remove magnetic and paramagnetic particles, such as heavy metals, from waste water. As the suspension flows through a magnetized filter mesh, high magnetic gradients around the wires attract and capture the particles, removing them from the fluid. We model such a system by considering the motion of a paramagnetic tracer particle through a periodic array of magnetized cylinders. We show that there is a critical Mason number (ratio of viscous to magnetic forces) below which the particle is captured irrespective of its initial position in the array. Above this threshold, particle capture is only partially successful and depends on the particle's entry position. We determine the relationship between the critical Mason number and the system geometry using numerical and asymptotic calculations. If a capture efficiency below 100% is sufficient, our results demonstrate how operating the HGMS system above the critical Mason number but with multiple separa...

  19. Modelling of cyclopentane promoted gas hydrate systems for carbon dioxide capture processes

    DEFF Research Database (Denmark)

    Herslund, Peter Jørgensen; Thomsen, Kaj; Abildskov, Jens

    2014-01-01

    amount of reliable LLE data exist for the binary system of water and cyclopentane. Additional water-in-oil data in particular are desired for this system.An unpromoted hydrate-based capture process, operating isothermally at a temperature of 280. K is simulated. The minimum pressure requirement...... behaviour and hydrate phase behaviour is presented. Cycloalkanes ranging from cyclopropane to cyclohexane, represents a challenge for CPA, both in the description of the pure component densities and for liquid-liquid equilibrium (LLE) in the binary systems with water. It is concluded that an insufficient...... of the first stage is estimated to be 24.9. MPa. Applying three consecutive hydrate formation/dissociation stages (three-stage capture process), a carbon dioxide-rich product (97. mol%) may be delivered at a temperature of 280. K and a pressure of 3.65. MPa.A second capture process, where cyclopentane...

  20. SIMULATION OF COLLECTIVE RISK MODEL

    Directory of Open Access Journals (Sweden)

    Viera Pacáková

    2007-12-01

    Full Text Available The article focuses on providing brief theoretical definitions of the basic terms and methods of modeling and simulations of insurance risks in non-life insurance by means of mathematical and statistical methods using statistical software. While risk assessment of insurance company in connection with its solvency is a rather complex and comprehensible problem, its solution starts with statistical modeling of number and amount of individual claims. Successful solution of these fundamental problems enables solving of curtail problems of insurance such as modeling and simulation of collective risk, premium an reinsurance premium calculation, estimation of probabiliy of ruin etc. The article also presents some essential ideas underlying Monte Carlo methods and their applications to modeling of insurance risk. Solving problem is to find the probability distribution of the collective risk in non-life insurance portfolio. Simulation of the compound distribution function of the aggregate claim amount can be carried out, if the distibution functions of the claim number process and the claim size are assumed given. The Monte Carlo simulation is suitable method to confirm the results of other methods and for treatments of catastrophic claims, when small collectives are studied. Analysis of insurance risks using risk theory is important part of the project Solvency II. Risk theory is analysis of stochastic features of non-life insurance process. The field of application of risk theory has grown rapidly. There is a need to develop the theory into form suitable for practical purposes and demostrate their application. Modern computer simulation techniques open up a wide field of practical applications for risk theory concepts, without requiring the restricive assumptions and sophisticated mathematics. This article presents some comparisons of the traditional actuarial methods and of simulation methods of the collective risk model.

  1. A capture-recapture model of amphidromous fish dispersal

    Science.gov (United States)

    Smith, W.; Kwak, Thomas J.

    2014-01-01

    Adult movement scale was quantified for two tropical Caribbean diadromous fishes, bigmouth sleeper Gobiomorus dormitor and mountain mullet Agonostomus monticola, using passive integrated transponders (PITs) and radio-telemetry. Large numbers of fishes were tagged in Rio Mameyes, Puerto Rico, U.S.A., with PITs and monitored at three fixed locations over a 2-5 year period to estimate transition probabilities between upper and lower elevations and survival probabilities with a multistate Cormack-Jolly-Seber model. A sub-set of fishes were tagged with radio-transmitters and tracked at weekly intervals to estimate fine-scale dispersal. Changes in spatial and temporal distributions of tagged fishes indicated that neither G. dormitor nor A. monticola moved into the lowest, estuarine reaches of Rio Mameyes during two consecutive reproductive periods, thus demonstrating that both species follow an amphidromous, rather than catadromous, migratory strategy. Further, both species were relatively sedentary, with restricted linear ranges. While substantial dispersal of these species occurs at the larval stage during recruitment to fresh water, the results indicate minimal dispersal in spawning adults. Successful conservation of diadromous fauna on tropical islands requires management at both broad basin and localized spatial scales.

  2. Dynamics modeling and control of a 6-DOF space robot with flexible panels for capturing a free floating target

    Science.gov (United States)

    Yu, Zhang-wei; Liu, Xiao-feng; Cai, Guo-ping

    2016-11-01

    In many kinds of on-orbit space robot tasks, capturing free floating target using space robot attracts more attention of researchers. However, most existing researches about dynamics and control of space robot concern planar problem, and the effect of flexible panel on capturing dynamics of the system is not considered. In this paper, spatial dynamics and control of a 6-DOF space robot with flexible panels are investigated and spatial impact problem is considered. Dynamic model of the system is established by the single direction recursive construction method and the Jourdain's velocity variation principle. The Hertz contact and impact theory and the method of computer graphics are used to establish the impact model. The computed torque control method is used to design active controller to suppress the spacecraft drift caused by the impact. Numerical simulation results show that the established dynamic model is effective in describing the dynamics behavior of the space robot; flexible panels have big influence on impact dynamic characteristics; the designed controller may effectively control the spacecraft drift during the capture process.

  3. Modeling the detection efficiency of an HP-Ge detector for use in boron neutron capture therapy.

    Science.gov (United States)

    Nakamura, Satoshi; Wakita, Akihisa; Ito, Masashi; Okamoto, Hiroyuki; Nishioka, Shie; Iijima, Kotaro; Kobayashi, Kazuma; Nishio, Teiji; Igaki, Hiroshi; Itami, Jun

    2017-07-01

    The multi-foil method is commonly used to determine upon an energy spectrum of neutrons in boron neutron capture therapy. The method requires to measure the radioactivation of the foils. This study develops a simple modeling procedure of a high-purity Ge detector, which is used to measure the radioactivation, in order to calculate the detection efficiency with GEANT4. By changing four parameters from their manufacturing specifications of the detector, the simulated detection efficiency is able to reproduce the actual detection efficiency. Copyright © 2017 Elsevier Ltd. All rights reserved.

  4. MODELLING, SIMULATING AND OPTIMIZING BOILERS

    DEFF Research Database (Denmark)

    Sørensen, K.; Condra, T.; Houbak, Niels

    2003-01-01

    This paper describes the modelling, simulating and optimizing including experimental verification as being carried out as part of a Ph.D. project being written resp. supervised by the authors. The work covers dynamic performance of both water-tube boilers and fire tube boilers. A detailed dynamic...... model of the boiler has been developed and simulations carried out by means of the Matlab integration routines. The model is prepared as a dynamic model consisting of both ordinary differential equations and algebraic equations, together formulated as a Differential-Algebraic-Equation system. Being able...... to operate a boiler plant dynamically means that the boiler designs must be able to absorb any fluctuations in water level and temperature gradients resulting from the pressure change in the boiler. On the one hand a large water-/steam space may be required, i.e. to build the boiler as big as possible. Due...

  5. A framework of motion capture system based human behaviours simulation for ergonomic analysis

    CERN Document Server

    Ma, Ruina; Bennis, Fouad; Ma, Liang

    2011-01-01

    With the increasing of computer capabilities, Computer aided ergonomics (CAE) offers new possibilities to integrate conventional ergonomic knowledge and to develop new methods into the work design process. As mentioned in [1], different approaches have been developed to enhance the efficiency of the ergonomic evaluation. Ergonomic expert systems, ergonomic oriented information systems, numerical models of human, etc. have been implemented in numerical ergonomic software. Until now, there are ergonomic software tools available, such as Jack, Ergoman, Delmia Human, 3DSSPP, and Santos, etc. [2-4]. The main functions of these tools are posture analysis and posture prediction. In the visualization part, Jack and 3DSSPP produce results to visualize virtual human tasks in 3-dimensional, but without realistic physical properties. Nowadays, with the development of computer technology, the simulation of physical world is paid more attention. Physical engines [5] are used more and more in computer game (CG) field. The a...

  6. Intelligent Mobility Modeling and Simulation

    Science.gov (United States)

    2015-03-04

    cog.cs.drexel.edu/act-r/index.html) •Models sensory / motor performance of human driver or teleoperator 27UNCLASSIFIED: Distribution Statement A. Approved for...U.S. ARMY TANK AUTOMOTIVE RESEARCH, DEVELOPMENT AND ENGINEERING CENTER Intelligent Mobility Modeling and Simulation 1 Dr. P. Jayakumar, S. Arepally...Prescribed by ANSI Std Z39-18 Contents 1. Mobility - Autonomy - Latency Relationship 2. Machine - Human Partnership 3. Development of Shared Control

  7. Extent of thermal ablation suffered by model organic microparticles during aerogel capture at hypervelocities

    Science.gov (United States)

    Burchell, M. J.; Foster, N. J.; Ormond-Prout, J.; Dupin, D.; Armes, S. P.

    2009-11-01

    New model organic microparticles are used to assess the thermal ablation that occurs during aerogel capture at speeds from 1 to 6 km s-1. Commercial polystyrene particles (20 µm diameter) were coated with an ultrathin 20 nm overlayer of an organic conducting polymer, polypyrrole. This overlayer comprises only 0.8% by mass of the projectile but has a very strong Raman signature, hence its survival or destruction is a sensitive measure of the extent of chemical degradation suffered. After aerogel capture, microparticles were located via optical microscopy and their composition was analyzed in situ using Raman microscopy. The ultrathin polypyrrole overlayer survived essentially intact for impacts at ~1 km s-1, but significant surface carbonization was found at 2 km s-1, and major particle mass loss at ≥3 km s-1. Particles impacting at ~6.1 km s-1 (the speed at which cometary dust was collected in the NASA Stardust mission) were reduced to approximately half their original diameter during aerogel capture (i.e., a mass loss of 84%). Thus significant thermal ablation occurs at speeds above a few km s-1. This suggests that during the Stardust mission the thermal history of the terminal dust grains during capture in aerogel may be sufficient to cause significant processing or loss of organic materials. Further, while Raman D and G bands of carbon can be obtained from captured grains, they may well reflect the thermal processing during capture rather than the pre-impact particle’s thermal history.

  8. Digital representations of the real world how to capture, model, and render visual reality

    CERN Document Server

    Magnor, Marcus A; Sorkine-Hornung, Olga; Theobalt, Christian

    2015-01-01

    Create Genuine Visual Realism in Computer Graphics Digital Representations of the Real World: How to Capture, Model, and Render Visual Reality explains how to portray visual worlds with a high degree of realism using the latest video acquisition technology, computer graphics methods, and computer vision algorithms. It explores the integration of new capture modalities, reconstruction approaches, and visual perception into the computer graphics pipeline.Understand the Entire Pipeline from Acquisition, Reconstruction, and Modeling to Realistic Rendering and ApplicationsThe book covers sensors fo

  9. Modeling the Formation and Evolution of Wind-Capture Disks In Binary Systems

    Science.gov (United States)

    Huarte-Espinosa, M.; Carroll-Nellenback, J.; Nordhaus, J.; Frank, A.; Blackman, E.

    2014-04-01

    In this talk I will present results of recent models of the formation, evolution and physical properties of accretion disks formed via wind capture in binary systems. Using the AMR code AstroBEAR, we have carried out high resolution 3D simulations that follow a stellar mass secondary in the co-rotating frame as it orbits a wind producing AGB primary. A resolution criteria, based on considerations of Bondi-Hoyle flows, must be met in order to properly resolve the formation of accretion disks around the secondary. We then compare simulations of binaries with three different orbital radii (10, 15, 20 AU). Disks are formed in all three cases, however the size of the disk and, most importantly, its accretion rate decreases with orbital radii. In addition, the shape of the orbital motions of material within the disk becomes increasingly elliptical with increasing binary separation. The flow is mildly unsteady with "fluttering" around the bow shock observed. The disks are generally well aligned with the orbital plane after a few binary orbits. We do not observe the presence of any large scale, violent instabilities (such as the flip-flop mode). For the first time it is observed that the wind component that is accreted towards the secondary has a vortex tube-like structure. In the context of AGB binary systems that might be precursors to Pre-Planetary and Planetary Nebula, we find that the wind accretion rates at the chosen orbital separations are generally too small to produce the most powerful outflows observed in these systems if the companions are main sequence stars but marginally capable if the companions are white dwarfs. It is likely that many of the more powerful PPN and PN involve closer binaries than the ones considered here.

  10. MODELLING, SIMULATING AND OPTIMIZING BOILERS

    DEFF Research Database (Denmark)

    Sørensen, Kim; Condra, Thomas Joseph; Houbak, Niels

    2004-01-01

    on the boiler) have been dened. Furthermore a number of constraints related to: minimum and maximum boiler load gradient, minimum boiler size, Shrinking and Swelling and Steam Space Load have been dened. For dening the constraints related to the required boiler volume a dynamic model for simulating the boiler...... performance has been developed. Outputs from the simulations are shrinking and swelling of water level in the drum during for example a start-up of the boiler, these gures combined with the requirements with respect to allowable water level uctuations in the drum denes the requirements with respect to drum...... size. The model has been formulated with a specied building-up of the pressure during the start-up of the plant, i.e. the steam production during start-up of the boiler is output from the model. The steam outputs together with requirements with respect to steam space load have been utilized to dene...

  11. Modeling and Simulation of Nanoindentation

    Science.gov (United States)

    Huang, Sixie; Zhou, Caizhi

    2017-08-01

    Nanoindentation is a hardness test method applied to small volumes of material which can provide some unique effects and spark many related research activities. To fully understand the phenomena observed during nanoindentation tests, modeling and simulation methods have been developed to predict the mechanical response of materials during nanoindentation. However, challenges remain with those computational approaches, because of their length scale, predictive capability, and accuracy. This article reviews recent progress and challenges for modeling and simulation of nanoindentation, including an overview of molecular dynamics, the quasicontinuum method, discrete dislocation dynamics, and the crystal plasticity finite element method, and discusses how to integrate multiscale modeling approaches seamlessly with experimental studies to understand the length-scale effects and microstructure evolution during nanoindentation tests, creating a unique opportunity to establish new calibration procedures for the nanoindentation technique.

  12. Multiscale Stochastic Simulation and Modeling

    Energy Technology Data Exchange (ETDEWEB)

    James Glimm; Xiaolin Li

    2006-01-10

    Acceleration driven instabilities of fluid mixing layers include the classical cases of Rayleigh-Taylor instability, driven by a steady acceleration and Richtmyer-Meshkov instability, driven by an impulsive acceleration. Our program starts with high resolution methods of numerical simulation of two (or more) distinct fluids, continues with analytic analysis of these solutions, and the derivation of averaged equations. A striking achievement has been the systematic agreement we obtained between simulation and experiment by using a high resolution numerical method and improved physical modeling, with surface tension. Our study is accompanies by analysis using stochastic modeling and averaged equations for the multiphase problem. We have quantified the error and uncertainty using statistical modeling methods.

  13. Parameter-expanded data augmentation for Bayesian analysis of capture-recapture models

    Science.gov (United States)

    Royle, J. Andrew; Dorazio, Robert M.

    2012-01-01

    Data augmentation (DA) is a flexible tool for analyzing closed and open population models of capture-recapture data, especially models which include sources of hetereogeneity among individuals. The essential concept underlying DA, as we use the term, is based on adding "observations" to create a dataset composed of a known number of individuals. This new (augmented) dataset, which includes the unknown number of individuals N in the population, is then analyzed using a new model that includes a reformulation of the parameter N in the conventional model of the observed (unaugmented) data. In the context of capture-recapture models, we add a set of "all zero" encounter histories which are not, in practice, observable. The model of the augmented dataset is a zero-inflated version of either a binomial or a multinomial base model. Thus, our use of DA provides a general approach for analyzing both closed and open population models of all types. In doing so, this approach provides a unified framework for the analysis of a huge range of models that are treated as unrelated "black boxes" and named procedures in the classical literature. As a practical matter, analysis of the augmented dataset by MCMC is greatly simplified compared to other methods that require specialized algorithms. For example, complex capture-recapture models of an augmented dataset can be fitted with popular MCMC software packages (WinBUGS or JAGS) by providing a concise statement of the model's assumptions that usually involves only a few lines of pseudocode. In this paper, we review the basic technical concepts of data augmentation, and we provide examples of analyses of closed-population models (M 0, M h , distance sampling, and spatial capture-recapture models) and open-population models (Jolly-Seber) with individual effects.

  14. A Model for Predicting Magnetic Particle Capture in a Microfluidic Bioseparator

    CERN Document Server

    Furlani, E P; Ng, K C; Sahoo, Y; Wortman, J C

    2006-01-01

    A model is presented for predicting the capture of magnetic micro/nano-particles in a bioseparation microsystem. This bioseparator consists of an array of conductive elements embedded beneath a rectangular microfluidic channel. The magnetic particles are introduced into the microchannel in solution, and are attracted and held by the magnetic force produced by the energized elements. Analytical expressions are obtained for the dominant magnetic and fluidic forces on the particles as they move through the microchannel. These expressions are included in the equations of motion, which are solved numerically to predict particle trajectories and capture time. This model is well-suited for parametric analysis of particle capture taking into account variations in particle size, material properties, applied current, microchannel dimensions, fluid properties, and flow velocity.

  15. Assessment of Molecular Modeling & Simulation

    Energy Technology Data Exchange (ETDEWEB)

    None

    2002-01-03

    This report reviews the development and applications of molecular and materials modeling in Europe and Japan in comparison to those in the United States. Topics covered include computational quantum chemistry, molecular simulations by molecular dynamics and Monte Carlo methods, mesoscale modeling of material domains, molecular-structure/macroscale property correlations like QSARs and QSPRs, and related information technologies like informatics and special-purpose molecular-modeling computers. The panel's findings include the following: The United States leads this field in many scientific areas. However, Canada has particular strengths in DFT methods and homogeneous catalysis; Europe in heterogeneous catalysis, mesoscale, and materials modeling; and Japan in materials modeling and special-purpose computing. Major government-industry initiatives are underway in Europe and Japan, notably in multi-scale materials modeling and in development of chemistry-capable ab-initio molecular dynamics codes.

  16. Animal models for simulating weightlessness

    Science.gov (United States)

    Morey-Holton, E.; Wronski, T. J.

    1982-01-01

    NASA has developed a rat model to simulate on earth some aspects of the weightlessness alterations experienced in space, i.e., unloading and fluid shifts. Comparison of data collected from space flight and from the head-down rat suspension model suggests that this model system reproduces many of the physiological alterations induced by space flight. Data from various versions of the rat model are virtually identical for the same parameters; thus, modifications of the model for acute, chronic, or metabolic studies do not alter the results as long as the critical components of the model are maintained, i.e., a cephalad shift of fluids and/or unloading of the rear limbs.

  17. Reference dosimetry calculations for neutron capture therapy with comparison of analytical and voxel models.

    Science.gov (United States)

    Goorley, J T; Kiger, W S; Zamenhof, R G

    2002-02-01

    As clinical trials of Neutron Capture Therapy (NCT) are initiated in the U.S. and other countries, new treatment planning codes are being developed to calculate detailed dose distributions in patient-specific models. The thorough evaluation and comparison of treatment planning codes is a critical step toward the eventual standardization of dosimetry, which, in turn, is an essential element for the rational comparison of clinical results from different institutions. In this paper we report development of a reference suite of computational test problems for NCT dosimetry and discuss common issues encountered in these calculations to facilitate quantitative evaluations and comparisons of NCT treatment planning codes. Specifically, detailed depth-kerma rate curves were calculated using the Monte Carlo radiation transport code MCNP4B for four different representations of the modified Snyder head phantom, an analytic, multishell, ellipsoidal model, and voxel representations of this model with cubic voxel sizes of 16, 8, and 4 mm. Monoenergetic and monodirectional beams of 0.0253 eV, 1, 2, 10, 100, and 1000 keV neutrons, and 0.2, 0.5, 1, 2, 5, and 10 MeV photons were individually simulated to calculate kerma rates to a statistical uncertainty of neutron beam with a broad neutron spectrum, similar to epithermal beams currently used or proposed for NCT clinical trials, was computed for all models. The thermal neutron, fast neutron, and photon kerma rates calculated with the 4 and 8 mm voxel models were within 2% and 4%, respectively, of those calculated for the analytical model. The 16 mm voxel model produced unacceptably large discrepancies for all dose components. The effects from different kerma data sets and tissue compositions were evaluated. Updating the kerma data from ICRU 46 to ICRU 63 data produced less than 2% difference in kerma rate profiles. The depth-dose profile data, Monte Carlo code input, kerma factors, and model construction files are available

  18. Simulation Tool for Inventory Models: SIMIN

    OpenAIRE

    Pratiksha Saxen; Tulsi Kushwaha

    2014-01-01

    In this paper, an integrated simulation optimization model for the inventory system is developed. An effective algorithm is developed to evaluate and analyze the back-end stored simulation results. This paper proposes simulation tool SIMIN (Inventory Simulation) to simulate inventory models. SIMIN is a tool which simulates and compares the results of different inventory models. To overcome various practical restrictive assumptions, SIMIN provides values for a number of performance measurement...

  19. How important is heterogeneous parameter distribution in capturing the catchment response through hydrologic modelling?

    Science.gov (United States)

    Devak, Manjula; Dhanya, Ct

    2017-04-01

    falling inside the basin. The performance analysis of HoSCP and HeSCP sets is done by developing the VIC model for Mahanadi basin, India, at two spatial (2° and 0.25°) and temporal (daily and monthly) resolutions. The model performance is analysed using various performance measures (NSE, RSR, R2 and PBIAS). Comparison of the annual flow patterns and the frequencies for both HeSCP and HoSCP sets, reveals that the finer resolution (0.25°) is more sensitive to the parameter distribution as compared to the coarse resolution (2°). HeSCP distribution captures annual cycle and frequencies better with relatively low uncertainty, as compared to HoSCP set. The long-term averages simulated by HeSCP set only deviates from observed data by 93 cumecs while those simulated by HoSCP deviates by 338 cumecs. Further, parameter variability is analyzed by assessing wet (>90% of observed data) and dry (help to improve the performance of hydrological modelling studies in any region. Keyword: Hydrological modelling, Auto-calibration, Parameter transferability, Heterogeneity, Semi-distributed model.

  20. Regenerable sorbents for mercury capture in simulated coal combustion flue gas.

    Science.gov (United States)

    Rodríguez-Pérez, Jorge; López-Antón, M Antonia; Díaz-Somoano, Mercedes; García, Roberto; Martínez-Tarazona, M Rosa

    2013-09-15

    This work demonstrates that regenerable sorbents containing nano-particles of gold dispersed on an activated carbon are efficient and long-life materials for capturing mercury species from coal combustion flue gases. These sorbents can be used in such a way that the high investment entailed in their preparation will be compensated for by the recovery of all valuable materials. The characteristics of the support and dispersion of gold in the carbon surface influence the efficiency and lifetime of the sorbents. The main factor that determines the retention of mercury and the regeneration of the sorbent is the presence of reactive gases that enhance mercury retention capacity. The capture of mercury is a consequence of two mechanisms: (i) the retention of elemental mercury by amalgamation with gold and (ii) the retention of oxidized mercury on the activated carbon support. These sorbents were specifically designed for retaining the mercury remaining in gas phase after the desulfurization units in coal power plants.

  1. Investigation of Isfahan miniature neutron source reactor (MNSR) for boron neutron capture therapy by MCNP simulation

    OpenAIRE

    S. Z. Kalantari; H Tavakoli; Nami, M.

    2015-01-01

    One of the important neutron sources for Boron Neutron Capture Therapy (BNCT) is a nuclear reactor. It needs a high flux of epithermal neutrons. The optimum conditions of the neutron spectra for BNCT are provided by the International Atomic Energy Agency (IAEA). In this paper, Miniature Neutron Source Reactor (MNSR) as a neutron source for BNCT was investigated. For this purpose, we designed a Beam Shaping Assembly (BSA) for the reactor and the neutron transport from the core of the reactor t...

  2. Steady-state simulation and optimization of an integrated gasification combined cycle power plant with CO2 capture

    Energy Technology Data Exchange (ETDEWEB)

    Bhattacharyya, D.; Turton, R.; Zitney, S.

    2011-01-01

    Integrated gasification combined cycle (IGCC) plants are a promising technology option for power generation with carbon dioxide (CO2) capture in view of their efficiency and environmental advantages over conventional coal utilization technologies. This paper presents a three-phase, top-down, optimization-based approach for designing an IGCC plant with precombustion CO2 capture in a process simulator environment. In the first design phase, important global design decisions are made on the basis of plant-wide optimization studies with the aim of increasing IGCC thermal efficiency and thereby making better use of coal resources and reducing CO2 emissions. For the design of an IGCC plant with 90% CO2 capture, the optimal combination of the extent of carbon monoxide (CO) conversion in the water-gas shift (WGS) reactors and the extent of CO2 capture in the SELEXOL process, using dimethylether of polyethylene glycol as the solvent, is determined in the first phase. In the second design phase, the impact of local design decisions is explored considering the optimum values of the decision variables from the first phase as additional constraints. Two decisions are made focusing on the SELEXOL and Claus unit. In the third design phase, the operating conditions are optimized considering the optimum values of the decision variables from the first and second phases as additional constraints. The operational flexibility of the plant must be taken into account before taking final design decisions. Two studies on the operational flexibility of the WGS reactors and one study focusing on the operational flexibility of the sour water stripper (SWS) are presented. At the end of the first iteration, after executing all the phases once, the net plant efficiency (HHV basis) increases to 34.1% compared to 32.5% in a previously published study (DOE/NETL-2007/1281; National Energy Technology Laboratory, 2007). The study shows that the three-phase, top-down design approach presented is very

  3. SIRS Dynamics on Random Networks: Simulations and Analytical Models

    Science.gov (United States)

    Rozhnova, Ganna; Nunes, Ana

    The standard pair approximation equations (PA) for the Susceptible-Infective-Recovered-Susceptible (SIRS) model of infection spread on a network of homogeneous degree k predict a thin phase of sustained oscillations for parameter values that correspond to diseases that confer long lasting immunity. Here we present a study of the dependence of this oscillatory phase on the parameter k and of its relevance to understand the behaviour of simulations on networks. For k = 4, we compare the phase diagram of the PA model with the results of simulations on regular random graphs (RRG) of the same degree. We show that for parameter values in the oscillatory phase, and even for large system sizes, the simulations either die out or exhibit damped oscillations, depending on the initial conditions. This failure of the standard PA model to capture the qualitative behaviour of the simulations on large RRGs is currently being investigated.

  4. Standard for Models and Simulations

    Science.gov (United States)

    Steele, Martin J.

    2016-01-01

    This NASA Technical Standard establishes uniform practices in modeling and simulation to ensure essential requirements are applied to the design, development, and use of models and simulations (MS), while ensuring acceptance criteria are defined by the program project and approved by the responsible Technical Authority. It also provides an approved set of requirements, recommendations, and criteria with which MS may be developed, accepted, and used in support of NASA activities. As the MS disciplines employed and application areas involved are broad, the common aspects of MS across all NASA activities are addressed. The discipline-specific details of a given MS should be obtained from relevant recommended practices. The primary purpose is to reduce the risks associated with MS-influenced decisions by ensuring the complete communication of the credibility of MS results.

  5. INTEGRATED DATA CAPTURING REQUIREMENTS FOR 3D SEMANTIC MODELLING OF CULTURAL HERITAGE: THE INCEPTION PROTOCOL

    Directory of Open Access Journals (Sweden)

    R. Di Giulio

    2017-02-01

    In order to face these challenges and to start solving the issue of the large amount of captured data and time-consuming processes in the production of 3D digital models, an Optimized Data Acquisition Protocol (DAP has been set up. The purpose is to guide the processes of digitization of cultural heritage, respecting needs, requirements and specificities of cultural assets.

  6. Model-Independent Calculation of Radiative Neutron Capture on Lithium-7

    NARCIS (Netherlands)

    Rupak, Gautam; Higa, Renato

    2011-01-01

    The radiative neutron capture on lithium-7 is calculated model independently using a low-energy halo effective field theory. The cross section is expressed in terms of scattering parameters directly related to the S-matrix elements. It depends on the poorly known p-wave effective range parameter r(1

  7. Thermodynamic and Process Modelling of Gas Hydrate Systems in CO2 Capture Processes

    DEFF Research Database (Denmark)

    Herslund, Peter Jørgensen

    A novel gas separation technique based on gas hydrate formation (solid precipitation) is investigated by means of thermodynamic modeling and experimental investigations. This process has previously been proposed for application in post-combustion carbon dioxide capture from power station flue gas...

  8. Integrating resource selection into spatial capture-recapture models for large carnivores

    Science.gov (United States)

    K. M. Proffitt; J. F. Goldberg; M. Hebblewhite; R. Russell; B. S. Jimenez; H. S. Robinson; Kristine Pilgrim; Michael Schwartz

    2015-01-01

    Wildlife managers need reliable methods to estimate large carnivore densities and population trends; yet large carnivores are elusive, difficult to detect, and occur at low densities making traditional approaches intractable. Recent advances in spatial capture-recapture (SCR) models have provided new approaches for monitoring trends in wildlife abundance and...

  9. Capturing optically important constituents and properties in a marine biogeochemical and ecosystem model

    Directory of Open Access Journals (Sweden)

    S. Dutkiewicz

    2015-07-01

    This new model that captures bio-optical feedbacks will be important for improving our understanding of the role of light and optical constituents on ocean biogeochemistry, especially in a changing environment. Further, resolving surface upwelling irradiance will make it easier to connect to satellite-derived products in the future.

  10. A minimal unified model of disease trajectories captures hallmarks of multiple sclerosis

    KAUST Repository

    Kannan, Venkateshan

    2017-03-29

    Multiple Sclerosis (MS) is an autoimmune disease targeting the central nervous system (CNS) causing demyelination and neurodegeneration leading to accumulation of neurological disability. Here we present a minimal, computational model involving the immune system and CNS that generates the principal subtypes of the disease observed in patients. The model captures several key features of MS, especially those that distinguish the chronic progressive phase from that of the relapse-remitting. In addition, a rare subtype of the disease, progressive relapsing MS naturally emerges from the model. The model posits the existence of two key thresholds, one in the immune system and the other in the CNS, that separate dynamically distinct behavior of the model. Exploring the two-dimensional space of these thresholds, we obtain multiple phases of disease evolution and these shows greater variation than the clinical classification of MS, thus capturing the heterogeneity that is manifested in patients.

  11. Model for Simulation Atmospheric Turbulence

    DEFF Research Database (Denmark)

    Lundtang Petersen, Erik

    1976-01-01

    A method that produces realistic simulations of atmospheric turbulence is developed and analyzed. The procedure makes use of a generalized spectral analysis, often called a proper orthogonal decomposition or the Karhunen-Loève expansion. A set of criteria, emphasizing a realistic appearance, a co....... The method is unique in modeling the three velocity components simultaneously, and it is found that important cross-statistical features are reasonably well-behaved. It is concluded that the model provides a practical, operational simulator of atmospheric turbulence.......A method that produces realistic simulations of atmospheric turbulence is developed and analyzed. The procedure makes use of a generalized spectral analysis, often called a proper orthogonal decomposition or the Karhunen-Loève expansion. A set of criteria, emphasizing a realistic appearance......, a correct spectral shape, and non-Gaussian statistics, is selected in order to evaluate the model turbulence. An actual turbulence record is analyzed in detail providing both a standard for comparison and input statistics for the generalized spectral analysis, which in turn produces a set of orthonormal...

  12. Likelihood analysis of spatial capture-recapture models for stratified or class structured populations

    Science.gov (United States)

    Royle, J. Andrew; Sutherland, Christopher S.; Fuller, Angela K.; Sun, Catherine C.

    2015-01-01

    We develop a likelihood analysis framework for fitting spatial capture-recapture (SCR) models to data collected on class structured or stratified populations. Our interest is motivated by the necessity of accommodating the problem of missing observations of individual class membership. This is particularly problematic in SCR data arising from DNA analysis of scat, hair or other material, which frequently yields individual identity but fails to identify the sex. Moreover, this can represent a large fraction of the data and, given the typically small sample sizes of many capture-recapture studies based on DNA information, utilization of the data with missing sex information is necessary. We develop the class structured likelihood for the case of missing covariate values, and then we address the scaling of the likelihood so that models with and without class structured parameters can be formally compared regardless of missing values. We apply our class structured model to black bear data collected in New York in which sex could be determined for only 62 of 169 uniquely identified individuals. The models containing sex-specificity of both the intercept of the SCR encounter probability model and the distance coefficient, and including a behavioral response are strongly favored by log-likelihood. Estimated population sex ratio is strongly influenced by sex structure in model parameters illustrating the importance of rigorous modeling of sex differences in capture-recapture models.

  13. Motion-capture-based walking simulation of digital human adapted to laser-scanned 3D as-is environments for accessibility evaluation

    Directory of Open Access Journals (Sweden)

    Tsubasa Maruyama

    2016-07-01

    Full Text Available Owing to our rapidly aging society, accessibility evaluation to enhance the ease and safety of access to indoor and outdoor environments for the elderly and disabled is increasing in importance. Accessibility must be assessed not only from the general standard aspect but also in terms of physical and cognitive friendliness for users of different ages, genders, and abilities. Meanwhile, human behavior simulation has been progressing in the areas of crowd behavior analysis and emergency evacuation planning. However, in human behavior simulation, environment models represent only “as-planned” situations. In addition, a pedestrian model cannot generate the detailed articulated movements of various people of different ages and genders in the simulation. Therefore, the final goal of this research was to develop a virtual accessibility evaluation by combining realistic human behavior simulation using a digital human model (DHM with “as-is” environment models. To achieve this goal, we developed an algorithm for generating human-like DHM walking motions, adapting its strides, turning angles, and footprints to laser-scanned 3D as-is environments including slopes and stairs. The DHM motion was generated based only on a motion-capture (MoCap data for flat walking. Our implementation constructed as-is 3D environment models from laser-scanned point clouds of real environments and enabled a DHM to walk autonomously in various environment models. The difference in joint angles between the DHM and MoCap data was evaluated. Demonstrations of our environment modeling and walking simulation in indoor and outdoor environments including corridors, slopes, and stairs are illustrated in this study.

  14. Dynamic simulation and load-following control of an integrated gasification combined cycle (IGCC) power plant with CO{sub 2} capture

    Energy Technology Data Exchange (ETDEWEB)

    Bhattacharyya, D,; Turton, R.; Zitney, S.

    2012-01-01

    Load-following control of future integrated gasification combined cycle (IGCC) plants with pre-combustion CO{sub 2} capture is expected to be far more challenging as electricity produced by renewable energy is connected to the grid and strict environmental limits become mandatory requirements. To study control performance during load following, a plant-wide dynamic simulation of a coal-fed IGCC plant with CO{sub 2} capture has been developed. The slurry-fed gasifier is a single-stage, downward-fired, oxygen-blown, entrained-flow type with a radiant syngas cooler (RSC). The syngas from the outlet of the RSC goes to a scrubber followed by a two-stage sour shift process with inter-stage cooling. The acid gas removal (AGR) process is a dual-stage physical solvent-based process for selective removal of H{sub 2}S in the first stage and CO{sub 2} in the second stage. Sulfur is recovered using a Claus unit with tail gas recycle to the AGR. The recovered CO{sub 2} is compressed by a split-shaft multistage compressor and sent for sequestration after being treated in an absorber with triethylene glycol for dehydration. The clean syngas is sent to two advanced “F”-class gas turbines (GTs) partially integrated with an elevated-pressure air separation unit. A subcritical steam cycle is used for heat recovery steam generation. A treatment unit for the sour water strips off the acid gases for utilization in the Claus unit. The steady-state model developed in Aspen Plus® is converted to an Aspen Plus Dynamics® simulation and integrated with MATLAB® for control studies. The results from the plant-wide dynamic model are compared qualitatively with the data from a commercial plant having different configuration, operating condition, and feed quality than what has been considered in this work. For load-following control, the GT-lead with gasifier-follow control strategy is considered. A modified proportional–integral–derivative (PID) control is considered for the syngas

  15. Particle capture in axial magnetic filters with power law flow model

    CERN Document Server

    Abbasov, T; Koksal, M

    1999-01-01

    A theory of capture of magnetic particle carried by laminar flow of viscous non-Newtonian (power law) fluid in axially ordered filters is presented. The velocity profile of the fluid flow is determined by the Kuwabara-Happel cell model. For the trajectory of the particle, the capture area and the filter performance simple analytical expressions are obtained. These expressions are valid for particle capture processes from both Newtonian and non-Newtonian fluids. For this reason the obtained theoretical results make it possible to widen the application of high-gradient magnetic filtration (HGMF) to other industrial areas. For Newtonian fluids the theoretical results are shown to be in good agreement with the experimental ones reported in the literature. (author)

  16. Particle capture in axial magnetic filters with power law flow model

    Science.gov (United States)

    Abbasov, T.; Herdem, S.; Köksal, M.

    1999-05-01

    A theory of capture of magnetic particle carried by laminar flow of viscous non-Newtonian (power law) fluid in axially ordered filters is presented. The velocity profile of the fluid flow is determined by the Kuwabara-Happel cell model. For the trajectory of the particle, the capture area and the filter performance simple analytical expressions are obtained. These expressions are valid for particle capture processes from both Newtonian and non-Newtonian fluids. For this reason the obtained theoretical results make it possible to widen the application of high-gradient magnetic filtration (HGMF) to other industrial areas. For Newtonian fluids the theoretical results are shown to be in good agreement with the experimental ones reported in the literature.

  17. Particle capture in axial magnetic filters with power law flow model

    Energy Technology Data Exchange (ETDEWEB)

    Abbasov, T.; Herdem, S.; Koksal, M. [Inonu University, Engineering Faculty, Department of Electrical and Electronics, Malatya (Turkey)

    1999-05-21

    A theory of capture of magnetic particle carried by laminar flow of viscous non-Newtonian (power law) fluid in axially ordered filters is presented. The velocity profile of the fluid flow is determined by the Kuwabara-Happel cell model. For the trajectory of the particle, the capture area and the filter performance simple analytical expressions are obtained. These expressions are valid for particle capture processes from both Newtonian and non-Newtonian fluids. For this reason the obtained theoretical results make it possible to widen the application of high-gradient magnetic filtration (HGMF) to other industrial areas. For Newtonian fluids the theoretical results are shown to be in good agreement with the experimental ones reported in the literature. (author)

  18. Neutrinoless double positron decay and positron emitting electron capture in the interacting boson model

    CERN Document Server

    Barea, J; Iachello, F

    2015-01-01

    Neutrinoless double-$\\beta$ decay is of fundamental importance for determining the neutrino mass. Although double electron ($\\beta^-\\beta^-$) decay is the most promising mode, in very recent years interest in double positron ($\\beta^+\\beta^+$) decay, positron emitting electron capture ($EC\\beta^+$), and double electron capture ($ECEC$) has been renewed. We present here results of a calculation of nuclear matrix elements for neutrinoless double-$\\beta^+$ decay and positron emitting electron capture within the framework of the microscopic interacting boson model (IBM-2) for $^{58}$Ni, $^{64}$Zn, $^{78}$Kr, $^{96}$Ru, $^{106}$Cd, $^{124}$Xe, $^{130}$Ba, and $^{136}$Ce decay. By combining these with a calculation of phase space factors we calculate expected half-lives.

  19. Impacts on the Hubble Space Telescope Wide Field and Planetary Camera 2: Experimental Simulation of Micrometeoroid Capture

    Science.gov (United States)

    Price, M. C.; Kearsley, A. T.; Wozniakiewicz, P. J.; Spratt, J.; Burchell, M. J.; Cole, M. J.; Anz-Meador, P.; Liou, J. C.; Ross, D. K.; Opiela, J.; hide

    2014-01-01

    Hypervelocity impact features have been recognized on painted surfaces returned from the Hubble Space Telescope (HST). Here we describe experiments that help us to understand their creation, and the preservation of micrometeoroid (MM) remnants. We simulated capture of silicate and sulfide minerals on the Zinc orthotitanate (ZOT) paint and Al alloy plate of the Wide Field and Planetary Camera 2 (WFPC2) radiator, which was returned from HST after 16 years in low Earth orbit (LEO). Our results also allow us to validate analytical methods for identification of MM (and orbital debris) impacts in LEO.

  20. HyCFS, a high-resolution shock capturing code for numerical simulation on hybrid computational clusters

    Science.gov (United States)

    Shershnev, Anton A.; Kudryavtsev, Alexey N.; Kashkovsky, Alexander V.; Khotyanovsky, Dmitry V.

    2016-10-01

    The present paper describes HyCFS code, developed for numerical simulation of compressible high-speed flows on hybrid CPU/GPU (Central Processing Unit / Graphical Processing Unit) computational clusters on the basis of full unsteady Navier-Stokes equations, using modern shock capturing high-order TVD (Total Variation Diminishing) and WENO (Weighted Essentially Non-Oscillatory) schemes on general curvilinear structured grids. We discuss the specific features of hybrid architecture and details of program implementation and present the results of code verification.

  1. Dynamic Modeling and Simulation of a Real World Billiard

    CERN Document Server

    Hartl, Alexandre E; Mazzoleni, Andre P

    2011-01-01

    Gravitational billiards provide an experimentally accessible arena for testing formulations of nonlinear dynamics. We present a mathematical model that captures the essential dynamics required for describing the motion of a realistic billiard for arbitrary boundaries. Simulations of the model are applied to parabolic, wedge and hyperbolic billiards that are driven sinusoidally. Direct comparisons are made between the model's predictions and previously published experimental data. It is shown that the data can be successfully modeled with a simple set of parameters without an assumption of exotic energy dependence.

  2. GEANT simulations of neutron capture experiments with a 4p BaF2 detector

    CERN Document Server

    Heil, M; Kaeppeler, F; Wisshak, K; Voss, F; Ullmann, J L; Haight, R C; Seabury, E H; Wilhelmy, J B; Rundberg, R S; Fowler, M M

    2004-01-01

    The goal of this research project is to give quantitative information useful for the design of a g-ray detector to investigate neutron capture (n, g) reactions on radioactive nuclei at the Manuel Lujan Jr. Neutron Scattering Center (MLNSC) moderated neutron source at LANSCE. Data for neutron energies from thermal up to approximately 500 keV are desired. The radioactive nuclei can have half-lives as short as a few months. With the sample sizes foreseen, typically 1 mg, the radioactive decay rate can exceed tens of Curies (Ci).

  3. Sunspot Modeling: From Simplified Models to Radiative MHD Simulations

    Directory of Open Access Journals (Sweden)

    Rolf Schlichenmaier

    2011-09-01

    Full Text Available We review our current understanding of sunspots from the scales of their fine structure to their large scale (global structure including the processes of their formation and decay. Recently, sunspot models have undergone a dramatic change. In the past, several aspects of sunspot structure have been addressed by static MHD models with parametrized energy transport. Models of sunspot fine structure have been relying heavily on strong assumptions about flow and field geometry (e.g., flux-tubes, "gaps", convective rolls, which were motivated in part by the observed filamentary structure of penumbrae or the necessity of explaining the substantial energy transport required to maintain the penumbral brightness. However, none of these models could self-consistently explain all aspects of penumbral structure (energy transport, filamentation, Evershed flow. In recent years, 3D radiative MHD simulations have been advanced dramatically to the point at which models of complete sunspots with sufficient resolution to capture sunspot fine structure are feasible. Here overturning convection is the central element responsible for energy transport, filamentation leading to fine-structure and the driving of strong outflows. On the larger scale these models are also in the progress of addressing the subsurface structure of sunspots as well as sunspot formation. With this shift in modeling capabilities and the recent advances in high resolution observations, the future research will be guided by comparing observation and theory.

  4. Dynamic simulation and optimization of an industrial-scale absorption tower for CO2 capturing from ethane gas

    Directory of Open Access Journals (Sweden)

    Babak Pouladi

    2016-11-01

    Full Text Available This article considers a process technology based on absorption for CO2 capturing of ethane gas in phase 9 and 10 of south pars in Iran using diethanolamine (DEA as absorbent solvent. This CO2 capture plant was designed to achieve 85% CO2 recovery and obtain 19 ppm the CO2 concentration in the outlet of absorber. ASPEN–HYSYS software was used for the dynamic simulation of a commercial-scale CO2 capture plant and amine Pkg equation was chosen from the fluid property package for calculating the thermodynamic properties of the process. A static approach for optimization was used to evaluate the optimum conditions. This research revealed that pressure variation does not have any considerable changes in the absorption process, while both amine inlet temperature and volumetric flow rate increment enhance the absorption tower efficiency. The effect of temperature was very significant as shown in the dynamic study plots. The optimum condition for CO2 absorption from a stream of ethane gas with molar flow rate of 2118 kg mol h−1 was obtained 75 m3  h−1 of amine at 53 °C and 24 bar. This optimized condition is acceptable from economical, safe as well as feasible point of view.

  5. Advances in Intelligent Modelling and Simulation Simulation Tools and Applications

    CERN Document Server

    Oplatková, Zuzana; Carvalho, Marco; Kisiel-Dorohinicki, Marek

    2012-01-01

    The human capacity to abstract complex systems and phenomena into simplified models has played a critical role in the rapid evolution of our modern industrial processes and scientific research. As a science and an art, Modelling and Simulation have been one of the core enablers of this remarkable human trace, and have become a topic of great importance for researchers and practitioners. This book was created to compile some of the most recent concepts, advances, challenges and ideas associated with Intelligent Modelling and Simulation frameworks, tools and applications. The first chapter discusses the important aspects of a human interaction and the correct interpretation of results during simulations. The second chapter gets to the heart of the analysis of entrepreneurship by means of agent-based modelling and simulations. The following three chapters bring together the central theme of simulation frameworks, first describing an agent-based simulation framework, then a simulator for electrical machines, and...

  6. Verifying and Validating Simulation Models

    Energy Technology Data Exchange (ETDEWEB)

    Hemez, Francois M. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

    2015-02-23

    This presentation is a high-level discussion of the Verification and Validation (V&V) of computational models. Definitions of V&V are given to emphasize that “validation” is never performed in a vacuum; it accounts, instead, for the current state-of-knowledge in the discipline considered. In particular comparisons between physical measurements and numerical predictions should account for their respective sources of uncertainty. The differences between error (bias), aleatoric uncertainty (randomness) and epistemic uncertainty (ignorance, lack-of- knowledge) are briefly discussed. Four types of uncertainty in physics and engineering are discussed: 1) experimental variability, 2) variability and randomness, 3) numerical uncertainty and 4) model-form uncertainty. Statistical sampling methods are available to propagate, and analyze, variability and randomness. Numerical uncertainty originates from the truncation error introduced by the discretization of partial differential equations in time and space. Model-form uncertainty is introduced by assumptions often formulated to render a complex problem more tractable and amenable to modeling and simulation. The discussion concludes with high-level guidance to assess the “credibility” of numerical simulations, which stems from the level of rigor with which these various sources of uncertainty are assessed and quantified.

  7. From radiation-induced chromosome damage to cell death: modelling basic mechanisms and applications to boron neutron capture therapy.

    Science.gov (United States)

    Ballarini, F; Bortolussi, S; Clerici, A M; Ferrari, C; Protti, N; Altieri, S

    2011-02-01

    Cell death is a crucial endpoint in radiation-induced biological damage: on one side, cell death is a reference endpoint to characterise the action of radiation in biological targets; on the other side, any cancer therapy aims to kill tumour cells. Starting from Lea's target theory, many models have been proposed to interpret radiation-induced cell killing; after briefly discussing some of these models, in this paper, a mechanistic approach based on an experimentally observed link between chromosome aberrations and cell death was presented. More specifically, a model and a Monte Carlo code originally developed for chromosome aberrations were extended to simulate radiation-induced cell death applying an experimentally observed one-to-one relationship between the average number of 'lethal aberrations' (dicentrics, rings and deletions) per cell and -ln S, S being the fraction of surviving cells. Although such observation was related to X rays, in the present work, the approach was also applied to protons and alpha particles. A good agreement between simulation outcomes and literature data provided a model validation for different radiation types. The same approach was then successfully applied to simulate the survival of cells enriched with boron and irradiated with thermal neutrons at the Triga Mark II reactor in Pavia, to mimic a typical treatment for boron neutron capture therapy.

  8. CO2 capture from simulated fuel gas mixtures using semiclathrate hydrates formed by quaternary ammonium salts.

    Science.gov (United States)

    Park, Sungwon; Lee, Seungmin; Lee, Youngjun; Seo, Yongwon

    2013-07-02

    In order to investigate the feasibility of semiclathrate hydrate-based precombustion CO2 capture, thermodynamic, kinetic, and spectroscopic studies were undertaken on the semiclathrate hydrates formed from a fuel gas mixture of H2 (60%) + CO2 (40%) in the presence of quaternary ammonium salts (QASs) such as tetra-n-butylammonium bromide (TBAB) and fluoride (TBAF). The inclusion of QASs demonstrated significantly stabilized hydrate dissociation conditions. This effect was greater for TBAF than TBAB. However, due to the presence of dodecahedral cages that are partially filled with water molecules, TBAF showed a relatively lower gas uptake than TBAB. From the stability condition measurements and compositional analyses, it was found that with only one step of semiclathrate hydrate formation with the fuel gas mixture from the IGCC plants, 95% CO2 can be enriched in the semiclathrate hydrate phase at room temperature. The enclathration of both CO2 and H2 in the cages of the QAS semiclathrate hydrates and the structural transition that results from the inclusion of QASs were confirmed through Raman and (1)H NMR measurements. The experimental results obtained in this study provide the physicochemical background required for understanding selective partitioning and distributions of guest gases in the QAS semiclathrate hydrates and for investigating the feasibility of a semiclathrate hydrate-based precombustion CO2 capture process.

  9. MODELLING, SIMULATING AND OPTIMIZING BOILERS

    DEFF Research Database (Denmark)

    Sørensen, Kim; Condra, Thomas Joseph; Houbak, Niels

    2004-01-01

    on the boiler) have been dened. Furthermore a number of constraints related to: minimum and maximum boiler load gradient, minimum boiler size, Shrinking and Swelling and Steam Space Load have been dened. For dening the constraints related to the required boiler volume a dynamic model for simulating the boiler...... size. The model has been formulated with a specied building-up of the pressure during the start-up of the plant, i.e. the steam production during start-up of the boiler is output from the model. The steam outputs together with requirements with respect to steam space load have been utilized to dene...... of the boiler is (with an acceptable accuracy) proportional with the volume of the boiler. For the dynamic operation capability a cost function penalizing limited dynamic operation capability and vise-versa has been dened. The main idea is that it by mean of the parameters in this function is possible to t its...

  10. Environmental assessment of amine-based carbon capture Scenario modelling with life cycle assessment (LCA)

    Energy Technology Data Exchange (ETDEWEB)

    Brekke, Andreas; Askham, Cecilia; Modahl, Ingunn Saur; Vold, Bjoern Ivar; Johnsen, Fredrik Moltu

    2012-07-01

    This report contains a first attempt at introducing the environmental impacts associated with amines and derivatives in a life cycle assessment (LCA) of gas power production with carbon capture and comparing these with other environmental impacts associated with the production system. The report aims to identify data gaps and methodological challenges connected both to modelling toxicity of amines and derivatives and weighting of environmental impacts. A scenario based modelling exercise was performed on a theoretical gas power plant with carbon capture, where emission levels of nitrosamines were varied between zero (gas power without CCS) to a worst case level (outside the probable range of actual carbon capture facilities). Because of extensive research and development in the areas of solvents and emissions from carbon capture facilities in the latter years, data used in the exercise may be outdated and results should therefore not be taken at face value.The results from the exercise showed: According to UseTox, emissions of nitrosamines are less important than emissions of formaldehyde with regard to toxicity related to operation of (i.e. both inputs to and outputs from) a carbon capture facility. If characterisation factors for emissions of metals are included, these outweigh all other toxic emissions in the study. None of the most recent weighting methods in LCA include characterisation factors for nitrosamines, and these are therefore not part of the environmental ranking.These results shows that the EDecIDe project has an important role to play in developing LCA methodology useful for assessing the environmental performance of amine based carbon capture in particular and CCS in general. The EDecIDe project will examine the toxicity models used in LCA in more detail, specifically UseTox. The applicability of the LCA compartment models and site specificity issues for a Norwegian/Arctic situation will be explored. This applies to the environmental compartments

  11. 机器人捕捉抛物的临场感仿真%Telepresence Simulation of Robots to Capture Parabolic

    Institute of Scientific and Technical Information of China (English)

    张克敏; 梁锡昌

    2012-01-01

    为开发基于虚拟现实的机器人,临场感仿真实验平台,对捕捉抛物的仿真成为必要。本文中提出了机器人捕捉抛物的仿真方法,以虚拟三自由度机器人捕捉虚拟小球为例进行了应用计算,包括求解正向运动学方程、逆向运动学方程,抛出虚拟小球的运动跟踪计算,捕捉点坐标的计算,最后结合初始位置以及规划的轨迹,得到了实现VS编程仿真的实时插补关节角度,并开发出了三自由度机器人临场感仿真平台中的相应程序。仿真结果表明了该方法的有效性。%In order to develop an experimental platform simulation robots on-site perception based on virtual reality, simulation of robots to capture parabolic is necessary, then a new method of simulation of robots to capture parabolic is p example to in this paper, and a virtual 3-DOF ( degree of freedom) robots capturing virtual globule is taken as an apply the present method in detail, including forward kinematics equation, inverse kinematics equation, calculation of motion tracking to throw out virtual globule, computation the coordinate of capturing point. Finally, together with the initial position and trajectory planning, the real-time interpolation joint angle for compiling VS (visual studio) program is derived, and experimental test were carried out on the 3-DOF robots platform, the re- suits demonstrate the validity of the algorithm.

  12. Selective Removal of Nitrosamines from a Model Amine Carbon-Capture Waterwash Using Low-Cost Activated-Carbon Sorbents.

    Science.gov (United States)

    Widger, Leland R; Combs, Megan; Lohe, Amit R; Lippert, Cameron A; Thompson, Jesse G; Liu, Kunlei

    2017-09-19

    Nitrosamines generated in the amine solvent loop of postcombustion carbon capture systems are potent carcinogens, and their emission could pose a serious threat to the environment or human health. Nitrosamine emission control strategies are critical for the success of amine-based carbon capture as the technology approaches industrial-scale deployment. Waterwash systems have been used to control volatile and aerosol emissions, including nitrosamines, from carbon-capture plants, but it is still necessary to remove or destroy nitrosamines in the circulating waterwash to prevent their subsequent emission into the environment. In this study, a cost-effective method for selectively removing nitrosamines from the absorber waterwash effluent with activated-carbon sorbents was developed to reduce the environmental impact associated with amine-based carbon capture. The results show that the commercial activated-carbon sorbents tested have a high capacity and selectivity for nitrosamines over the parent solvent amines, with capacities up to 190 mg/g carbon, under simulated amine waterwash conditions. To further reduce costs, an aerobic thermal sorbent regeneration step was also examined due to the low thermal stability of nitrosamines. To model the effect of oxidation on the sorbent performance, thermal- and acid-oxidized sorbents were also prepared from the commercial sorbents and analyzed. The chemical and physical properties of nitrosamines, the parent amine, and the influence of the physical properties of the carbon sorbents on nitrosamine adsorption was examined. Key sorbent properties included the sorbent hydrophilicity and hydrophobicity, surface pKa of the sorbent, and chemical structure of the parent amine and nitrosamine.

  13. Simulated annealing model of acupuncture

    Science.gov (United States)

    Shang, Charles; Szu, Harold

    2015-05-01

    The growth control singularity model suggests that acupuncture points (acupoints) originate from organizers in embryogenesis. Organizers are singular points in growth control. Acupuncture can cause perturbation of a system with effects similar to simulated annealing. In clinical trial, the goal of a treatment is to relieve certain disorder which corresponds to reaching certain local optimum in simulated annealing. The self-organizing effect of the system is limited and related to the person's general health and age. Perturbation at acupoints can lead a stronger local excitation (analogous to higher annealing temperature) compared to perturbation at non-singular points (placebo control points). Such difference diminishes as the number of perturbed points increases due to the wider distribution of the limited self-organizing activity. This model explains the following facts from systematic reviews of acupuncture trials: 1. Properly chosen single acupoint treatment for certain disorder can lead to highly repeatable efficacy above placebo 2. When multiple acupoints are used, the result can be highly repeatable if the patients are relatively healthy and young but are usually mixed if the patients are old, frail and have multiple disorders at the same time as the number of local optima or comorbidities increases. 3. As number of acupoints used increases, the efficacy difference between sham and real acupuncture often diminishes. It predicted that the efficacy of acupuncture is negatively correlated to the disease chronicity, severity and patient's age. This is the first biological - physical model of acupuncture which can predict and guide clinical acupuncture research.

  14. Density estimation in a wolverine population using spatial capture-recapture models

    Science.gov (United States)

    Royle, J. Andrew; Magoun, Audrey J.; Gardner, Beth; Valkenbury, Patrick; Lowell, Richard E.; McKelvey, Kevin

    2011-01-01

    Classical closed-population capture-recapture models do not accommodate the spatial information inherent in encounter history data obtained from camera-trapping studies. As a result, individual heterogeneity in encounter probability is induced, and it is not possible to estimate density objectively because trap arrays do not have a well-defined sample area. We applied newly-developed, capture-recapture models that accommodate the spatial attribute inherent in capture-recapture data to a population of wolverines (Gulo gulo) in Southeast Alaska in 2008. We used camera-trapping data collected from 37 cameras in a 2,140-km2 area of forested and open habitats largely enclosed by ocean and glacial icefields. We detected 21 unique individuals 115 times. Wolverines exhibited a strong positive trap response, with an increased tendency to revisit previously visited traps. Under the trap-response model, we estimated wolverine density at 9.7 individuals/1,000-km2(95% Bayesian CI: 5.9-15.0). Our model provides a formal statistical framework for estimating density from wolverine camera-trapping studies that accounts for a behavioral response due to baited traps. Further, our model-based estimator does not have strict requirements about the spatial configuration of traps or length of trapping sessions, providing considerable operational flexibility in the development of field studies.

  15. Equivalence between local Fermi gas and shell models in inclusive muon capture from nuclei

    Energy Technology Data Exchange (ETDEWEB)

    Amaro, J.E.; Nieves, J.; Valverde, M. [Universidad de Granada, Departamento de Fisica Moderna, Granada (Spain); Maieron, C. [INFN, Sezione di Catania, Catania (Italy)

    2005-06-01

    Motivated by recent studies of inclusive neutrino nucleus processes and muon capture within a correlated local Fermi gas model (LFG), we discuss the relevance of nuclear finite-size effects in these reactions at low energy, in particular for muon capture. To disentangle these effects from others coming from the reaction dynamics we employ here a simple uncorrelated shell model that embodies the typical finite-size content of the problem. The integrated decay widths of muon atoms calculated with this shell model are then compared for several nuclei with those obtained within the uncorrelated LFG, using in both models exactly the same theoretical ingredients and parameters. We find that the two predictions are in quite good agreement, within 1-7%, when the shell model density and the correct energy balance is used as input in the LFG calculation. The present study indicates that, despite the low excitation energies involved in the reaction, integrated inclusive observables, like the total muon capture width, are quite independent of the fine details of the nuclear wave functions. (orig.)

  16. Shock Particle Interaction - Fully Resolved Simulations and Modeling

    Science.gov (United States)

    Mehta, Yash; Neal, Chris; Jackson, Thomas L.; Balachandar, S. "Bala"; Thakur, Siddharth

    2016-11-01

    Currently there is a substantial lack of fully resolved data for shock interacting with multiple particles. In this talk we will fill this gap by presenting results of shock interaction with 1-D array and 3-D structured arrays of particles. Objectives of performing fully resolved simulations of shock propagation through packs of multiple particles are twofold, 1) To understand the complicated physical phenomena occurring during shock particle interaction, and 2) To translate the knowledge from microscale simulations in building next generation point-particle models for macroscale simulations that can better predict the motion (forces) and heat transfer for particles. We compare results from multiple particle simulations against the single particle simulations and make relevant observations. The drag history and flow field for multiple particle simulations are markedly different from those of single particle simluations, highlighting the effect of neighboring particles. We propose new models which capture this effect of neighboring particles. These models are called Pair-wise Interaction Extended Point Particle models (PIEP). Effect of multiple neighboring particles is broken down into pair-wise interactions, and these pair-wise interactions are superimposed to get the final model U.S. Department of Energy, National Nuclear Security Administration, Advanced Simulation and Computing Program, as a Cooperative Agreement under the Predictive Science Academic Alliance Program, under Contract No. DE-NA0002378.

  17. Simulation and multivariable optimization of post-combustion capture using piperazine

    DEFF Research Database (Denmark)

    Gaspar, Jozsef; Fosbøl, Philip Loldrup

    2016-01-01

    Piperazine presents a great potential to develop an energy efficient solvent based CO2 post-combustion capture process. Recently 8 molal piperazine (PZ) has shown promising results, however it faces operational challenges due to limited solid solubility. The operating range can be extended......, to avoid clogging from solid formation. 5 m PZ is the most promising trade-off between energy efficiency and solid-free operation with a specific reboiler duty of 3.22 GJ/t CO2 at 0.34 lean loading. The performance of the process can be further improved by assuming a minimum temperature of 30 °C which...... gives an optimal specific reboiler duty of 3.09 GJ/t CO2 (8 m PZ, 0.334 lean loading) for conditions without advanced heat integration....

  18. Uterine Contraction Modeling and Simulation

    Science.gov (United States)

    Liu, Miao; Belfore, Lee A.; Shen, Yuzhong; Scerbo, Mark W.

    2010-01-01

    Building a training system for medical personnel to properly interpret fetal heart rate tracing requires developing accurate models that can relate various signal patterns to certain pathologies. In addition to modeling the fetal heart rate signal itself, the change of uterine pressure that bears strong relation to fetal heart rate and provides indications of maternal and fetal status should also be considered. In this work, we have developed a group of parametric models to simulate uterine contractions during labor and delivery. Through analysis of real patient records, we propose to model uterine contraction signals by three major components: regular contractions, impulsive noise caused by fetal movements, and low amplitude noise invoked by maternal breathing and measuring apparatus. The regular contractions are modeled by an asymmetric generalized Gaussian function and least squares estimation is used to compute the parameter values of the asymmetric generalized Gaussian function based on uterine contractions of real patients. Regular contractions are detected based on thresholding and derivative analysis of uterine contractions. Impulsive noise caused by fetal movements and low amplitude noise by maternal breathing and measuring apparatus are modeled by rational polynomial functions and Perlin noise, respectively. Experiment results show the synthesized uterine contractions can mimic the real uterine contractions realistically, demonstrating the effectiveness of the proposed algorithm.

  19. Simulation and Modeling Application in Agricultural Mechanization

    Directory of Open Access Journals (Sweden)

    R. M. Hudzari

    2012-01-01

    Full Text Available This experiment was conducted to determine the equations relating the Hue digital values of the fruits surface of the oil palm with maturity stage of the fruit in plantation. The FFB images were zoomed and captured using Nikon digital camera, and the calculation of Hue was determined using the highest frequency of the value for R, G, and B color components from histogram analysis software. New procedure in monitoring the image pixel value for oil palm fruit color surface in real-time growth maturity was developed. The estimation of day harvesting prediction was calculated based on developed model of relationships for Hue values with mesocarp oil content. The simulation model is regressed and predicts the day of harvesting or a number of days before harvest of FFB. The result from experimenting on mesocarp oil content can be used for real-time oil content determination of MPOB color meter. The graph to determine the day of harvesting the FFB was presented in this research. The oil was found to start developing in mesocarp fruit at 65 days before fruit at ripe maturity stage of 75% oil to dry mesocarp.

  20. Capturing coherent structures and turbulent interfaces in wake flows by means of the Organised Eddy Simulation, OES and by Tomo-PIV

    Science.gov (United States)

    Deri, E.; Ouvrard, H.; Braza, M.; Hunt, J.; Hoarau, Y.; Cazin, S.; Cid, E.; Harran, G.

    2011-12-01

    The present study aims at a physical analysis of the coherent and chaotic vortex dynamics in the near wake around a flat plate at incidence, to provide new elements in respect of the flow physics turbulence modelling for high-Reynolds number flows around bodies. This constitutes nowadays a challenge in the aeronautics design. A special attention is paid to capture the thin shear layer interfaces downstream of the separation, responsible for aeroacoustics phenomena related to noise reduction and directly linked to an accurate prediction of the aerodynamic forces. The experimental investigation is carried out by means of tomographic PIV. The interaction of the most energetic coherent structures with the random turbulence is discussed. Furthermore, the POD analysis allowed evaluation of 3D phase averaged dynamics as well as the influence of higher modes associated with the finer-scale turbulence. The numerical study by means of the Organised Eddy Simulation, OES approach ensured a reduced turbulence diffusion that allowed development of the von Karman instability and of capturing of the thin shear-layer interfaces, by using appropriate criteria based on vorticity and dissipation rate of kinetic energy. A comparison between the experiments and the simulations concerning the coherent vortex pattern is carried out.

  1. Carbon dioxide capture in 2-aminoethanol aqueous solution from ab initio molecular dynamics simulations

    Science.gov (United States)

    Kubota, Yoshiyuki; Ohnuma, Toshiharu; Bučko, Tomáš

    2017-03-01

    The reaction of carbon dioxide (CO2) with aqueous 2-aminoethanol (MEA) has been investigated using both blue moon ensemble and metadynamics approaches combined with ab initio molecular dynamics (AIMD) simulations. The AIMD simulations predicted the spontaneous deprotonation of the intermediate compound, MEA zwitterion, and they were used to study two possible routes for subsequent proton transfer reactions: the formation of the protonated MEA and the formation of MEA carbamic acid. The free-energy curve depicted by blue moon ensemble technique supported the favorable deprotonation of MEA zwitterion. The overall free-energy profile showed the favorable formation of the ionic products of MEA carbamate ion and protonated MEA.

  2. Bayesian inference in camera trapping studies for a class of spatial capture-recapture models.

    Science.gov (United States)

    Royle, J Andrew; Karanth, K Ullas; Gopalaswamy, Arjun M; Kumar, N Samba

    2009-11-01

    We develop a class of models for inference about abundance or density using spatial capture-recapture data from studies based on camera trapping and related methods. The model is a hierarchical model composed of two components: a point process model describing the distribution of individuals in space (or their home range centers) and a model describing the observation of individuals in traps. We suppose that trap- and individual-specific capture probabilities are a function of distance between individual home range centers and trap locations. We show that the models can be regarded as generalized linear mixed models, where the individual home range centers are random effects. We adopt a Bayesian framework for inference under these models using a formulation based on data augmentation. We apply the models to camera trapping data on tigers from the Nagarahole Reserve, India, collected over 48 nights in 2006. For this study, 120 camera locations were used, but cameras were only operational at 30 locations during any given sample occasion. Movement of traps is common in many camera-trapping studies and represents an important feature of the observation model that we address explicitly in our application.

  3. Can a Time Fractional-Derivative Model Capture Scale-Dependent Dispersion in Saturated Soils?

    Science.gov (United States)

    Garrard, Rhiannon M; Zhang, Yong; Wei, Song; Sun, HongGuang; Qian, Jiazhong

    2017-07-10

    Time nonlocal transport models such as the time fractional advection-dispersion equation (t-fADE) were proposed to capture well-documented non-Fickian dynamics for conservative solutes transport in heterogeneous media, with the underlying assumption that the time nonlocality (which means that the current concentration change is affected by previous concentration load) embedded in the physical models can release the effective dispersion coefficient from scale dependency. This assumption, however, has never been systematically examined using real data. This study fills this historical knowledge gap by capturing non-Fickian transport (likely due to solute retention) documented in the literature (Huang et al. 1995) and observed in our laboratory from small to intermediate spatial scale using the promising, tempered t-fADE model. Fitting exercises show that the effective dispersion coefficient in the t-fADE, although differing subtly from the dispersion coefficient in the standard advection-dispersion equation, increases nonlinearly with the travel distance (varying from 0.5 to 12 m) for both heterogeneous and macroscopically homogeneous sand columns. Further analysis reveals that, while solute retention in relatively immobile zones can be efficiently captured by the time nonlocal parameters in the t-fADE, the motion-independent solute movement in the mobile zone is affected by the spatial evolution of local velocities in the host medium, resulting in a scale-dependent dispersion coefficient. The same result may be found for the other standard time nonlocal transport models that separate solute retention and jumps (i.e., displacement). Therefore, the t-fADE with a constant dispersion coefficient cannot capture scale-dependent dispersion in saturated porous media, challenging the application for stochastic hydrogeology methods in quantifying real-world, preasymptotic transport. Hence improvements on time nonlocal models using, for example, the novel subordination

  4. Applications of Joint Tactical Simulation Modeling

    Science.gov (United States)

    1997-12-01

    NAVAL POSTGRADUATE SCHOOL Monterey, California THESIS APPLICATIONS OF JOINT TACTICAL SIMULATION MODELING by Steve VanLandingham December 1997...SUBTITLE APPLICATIONS OF JOINT TACTICAL SIMULATION MODELING 5. FUNDING NUMBERS 6. AUTHOR(S) VanLandingham, Steve 7. PERFORMING ORGANIZATION NAME(S...release; distribution is unlimited. APPLICATIONS OF JOINT TACTICAL SIMULATION MODELING Steve VanLandingham Lieutenant, United States Navy B.S

  5. Benchmark simulation models, quo vadis?

    DEFF Research Database (Denmark)

    Jeppsson, U.; Alex, J; Batstone, D. J.

    2013-01-01

    As the work of the IWA Task Group on Benchmarking of Control Strategies for wastewater treatment plants (WWTPs) is coming to an end, it is essential to disseminate the knowledge gained. For this reason, all authors of the IWA Scientific and Technical Report on benchmarking have come together to p...... already being done within the context of the benchmarking simulation models (BSMs) or applicable work in the wider literature. Of key importance is increasing capability, usability and transparency of the BSM package while avoiding unnecessary complexity. © IWA Publishing 2013....... and spatial extension, process modifications within the WWTP, the realism of models, control strategy extensions and the potential for new evaluation tools within the existing benchmark system. We find that there are major opportunities for application within all of these areas, either from existing work...

  6. Particle capture efficiency in a multi-wire model for high gradient magnetic separation

    KAUST Repository

    Eisenträger, Almut

    2014-07-21

    High gradient magnetic separation (HGMS) is an efficient way to remove magnetic and paramagnetic particles, such as heavy metals, from waste water. As the suspension flows through a magnetized filter mesh, high magnetic gradients around the wires attract and capture the particles removing them from the fluid. We model such a system by considering the motion of a paramagnetic tracer particle through a periodic array of magnetized cylinders. We show that there is a critical Mason number (ratio of viscous to magnetic forces) below which the particle is captured irrespective of its initial position in the array. Above this threshold, particle capture is only partially successful and depends on the particle\\'s entry position. We determine the relationship between the critical Mason number and the system geometry using numerical and asymptotic calculations. If a capture efficiency below 100% is sufficient, our results demonstrate how operating the HGMS system above the critical Mason number but with multiple separation cycles may increase efficiency. © 2014 AIP Publishing LLC.

  7. Measurement and Modelling of the Piperazine Potassium Carbonate Solutions for CO2 Capture

    DEFF Research Database (Denmark)

    Fosbøl, Philip Loldrup; Thomsen, Kaj; Waseem Arshad, Muhammad

    The climate is in a critical state due to the impact of pollution by CO2 and similar greenhouse gasses. Action needs to be taken in order reduce the emission of harmful components. CO2 capture is one process to help the world population back on track in order to return to normal condition, obtain...... with the purpose of simulating the CO2 capture process. This involves equilibrium studies on physical properties in the activated carbonate solvent. Energy consumption while applying the promoted carbonate solutions using piperazine is given in overview.......The climate is in a critical state due to the impact of pollution by CO2 and similar greenhouse gasses. Action needs to be taken in order reduce the emission of harmful components. CO2 capture is one process to help the world population back on track in order to return to normal condition......, obtaining a sustainable use of natural organic resources. In this work the solid solubility has been measured for the promoted hot carbonate process using piperazine and K2CO3/KHCO3. It entails a comparison of several newly developed methods in order to guarantee the accuracy of determined experimental work...

  8. Enhancing data visualisation to capture the simulator sickness phenomenon: On the usefulness of radar charts

    Directory of Open Access Journals (Sweden)

    Romain Chaumillon

    2017-08-01

    Full Text Available The data presented in this article are related to the research article entitled “The use of transdermal scopolamine to solve methodological issues raised by gender differences in susceptibility to simulator sickness” (Chaumillon et al., 2017 [1]. In an outstanding first demonstration, Kennedy et al. [2] showed that the Simulator Sickness Questionnaire (SSQ is an appropriate tool to suit the purposes of characterizing motion sickness experienced in virtual environments. This questionnaire has since been used in many scientific studies. Recently, Balk et al. [3] suggested that the proposed segregation of SSQ scores into three subclasses of symptoms might limit the accuracy of simulator sickness assessment. These authors performed a factor analysis based on SSQ scores obtained from nine studies on driving simulators. Although their factor analysis resulted in the same three orthogonal classes of symptoms as Kennedy et al. [2], unlike this pioneering study, no items were attributed to more than one factor and five items were not attributed to any class of symptoms. As a result, they claimed that an exploration of each item score should give additional cues on individual profiles. To gain a better characterization of such item-by-item exploration, data utilised in this research are shown using a radar chart visualisation.

  9. SWEEPOP a simulation model for Target Simulation Mode minesweeping

    NARCIS (Netherlands)

    Keus, H.E.; Beckers, A.L.D.; Cleophas, P.L.H.

    2005-01-01

    SWEEPOP is a flexible model that simulates the physical interaction between objects in a maritime underwater environment. The model was built to analyse the deployment and the performance of a Target Simulation Mode (TSM) minesweeping system for the Royal Netherlands Navy (RNLN) and to support its p

  10. Correlations and total muon capture rates. [Primakoff effect, isospin, shell model

    Energy Technology Data Exchange (ETDEWEB)

    Mekjian, A.

    1978-08-01

    The total muon capture rate for s-wave muons can be accounted for by the Primakoff expression which gives the dependence of this rate on the mass number A and the proton number Z of the absorbing nucleus. The expression is a simple three parameter phenomenological formulae which accurately describes these rates from light weight nuclei to heavy nuclei. These parameters relate to the isospin structure of the squared isovector operator which appears in a sum rule approach to such rates. A microscopic analysis of the parameters appearing in the capture rate expression is presented in the light of recent developments concerning photonuclear reactions. A shell model analysis is given and it is found that the predictions of the unperturbed shell model and also Hartree-Fock theory are in complete disagreement with the data. Considerable improvement is obtained when long range correlations are included in the ground state wave function of the absorbing nucleus. 21 references.

  11. Improved parametrization of the unified model for alpha decay and alpha capture

    CERN Document Server

    Denisov, V Yu; Sedykh, I Yu

    2015-01-01

    The updated data for the ground-state-to-ground-state alpha-transition half-lives in 401 nuclei and the alpha capture cross sections of 40Ca, 44Ca, 59Co, 208Pb and 209Bi are well described in the framework of the unified model for alpha-decay and alpha-capture. The updated values of the alpha decay half-lives, the binding energies of nuclei, the spins of parent and daughter nuclei, and the surface deformation parameters are used for the reevaluation of the model parameters. The data for the ground-state-to-ground-state alpha-decay half-lives are also well described by the empirical relationships.

  12. Improving Prediction Accuracy of a Rate-Based Model of an MEA-Based Carbon Capture Process for Large-Scale Commercial Deployment

    Directory of Open Access Journals (Sweden)

    Xiaobo Luo

    2017-04-01

    Full Text Available Carbon capture and storage (CCS technology will play a critical role in reducing anthropogenic carbon dioxide (CO2 emission from fossil-fired power plants and other energy-intensive processes. However, the increment of energy cost caused by equipping a carbon capture process is the main barrier to its commercial deployment. To reduce the capital and operating costs of carbon capture, great efforts have been made to achieve optimal design and operation through process modeling, simulation, and optimization. Accurate models form an essential foundation for this purpose. This paper presents a study on developing a more accurate rate-based model in Aspen Plus® for the monoethanolamine (MEA-based carbon capture process by multistage model validations. The modeling framework for this process was established first. The steady-state process model was then developed and validated at three stages, which included a thermodynamic model, physical properties calculations, and a process model at the pilot plant scale, covering a wide range of pressures, temperatures, and CO2 loadings. The calculation correlations of liquid density and interfacial area were updated by coding Fortran subroutines in Aspen Plus®. The validation results show that the correlation combination for the thermodynamic model used in this study has higher accuracy than those of three other key publications and the model prediction of the process model has a good agreement with the pilot plant experimental data. A case study was carried out for carbon capture from a 250 MWe combined cycle gas turbine (CCGT power plant. Shorter packing height and lower specific duty were achieved using this accurate model.

  13. An invasive-native mammalian species replacement process captured by camera trap survey random encounter models

    OpenAIRE

    2016-01-01

    Camera traps are used to estimate densities or abundances using capture-recapture and, more recently, random encounter models (REMs). We deploy REMs to describe an invasive-native species replacement process, and to demonstrate their wider application beyond abundance estimation. The Irish hare Lepus timidus hibernicus is a high priority endemic of conservation concern. It is threatened by an expanding population of non-native, European hares L. europaeus, an invasive species of global import...

  14. Complexity of chromatin folding is captured by the strings and binders switch model

    OpenAIRE

    Barbieri, Mariano; Chotalia, Mita; Fraser, James; Lavitas, Liron-Mark; Dostie, Josée; Pombo, Ana; Nicodemi, Mario

    2012-01-01

    Chromatin has a complex spatial organization in the cell nucleus that serves vital functional purposes. A variety of chromatin folding conformations has been detected by single-cell imaging and chromosome conformation capture-based approaches. However, a unified quantitative framework describing spatial chromatin organization is still lacking. Here, we explore the “strings and binders switch” model to explain the origin and variety of chromatin behaviors that coexist and dynamically change wi...

  15. Investigation of model capability in capturing vertical hydrodynamic coastal processes: a case study in the north Adriatic Sea

    Science.gov (United States)

    McKiver, W. J.; Sannino, G.; Braga, F.; Bellafiore, D.

    2016-01-01

    In this work we consider a numerical study of hydrodynamics in the coastal zone using two different models, SHYFEM (shallow water hydrodynamic finite element model) and MITgcm (Massachusetts Institute of Technology general circulation model), to assess their capability to capture the main processes. We focus on the north Adriatic Sea during a strong dense water event that occurred at the beginning of 2012. This serves as an interesting test case to examine both the models strengths and weaknesses, while giving an opportunity to understand how these events affect coastal processes, like upwelling and downwelling, and how they interact with estuarine dynamics. Using the models we examine the impact of setup, surface and lateral boundary treatment, resolution and mixing schemes, as well as assessing the importance of nonhydrostatic dynamics in coastal processes. Both models are able to capture the dense water event, though each displays biases in different regions. The models show large differences in the reproduction of surface patterns, identifying the choice of suitable bulk formulas as a central point for the correct simulation of the thermohaline structure of the coastal zone. Moreover, the different approaches in treating lateral freshwater sources affect the vertical coastal stratification. The results indicate the importance of having high horizontal resolution in the coastal zone, specifically in close proximity to river inputs, in order to reproduce the effect of the complex coastal morphology on the hydrodynamics. A lower resolution offshore is acceptable for the reproduction of the dense water event, even if specific vortical structures are missed. Finally, it is found that nonhydrostatic processes are of little importance for the reproduction of dense water formation in the shelf of the north Adriatic Sea.

  16. A review of Bayesian state-space modelling of capture-recapture-recovery data.

    Science.gov (United States)

    King, Ruth

    2012-04-06

    Traditionally, state-space models are fitted to data where there is uncertainty in the observation or measurement of the system. State-space models are partitioned into an underlying system process describing the transitions of the true states of the system over time and the observation process linking the observations of the system to the true states. Open population capture-recapture-recovery data can be modelled in this framework by regarding the system process as the state of each individual observed within the study in terms of being alive or dead, and the observation process the recapture and/or recovery process. The traditional observation error of a state-space model is incorporated via the recapture/recovery probabilities being less than unity. The models can be fitted using a Bayesian data augmentation approach and in standard BUGS packages. Applying this state-space framework to such data permits additional complexities including individual heterogeneity to be fitted to the data at very little additional programming effort. We consider the efficiency of the state-space model fitting approach by considering a random effects model for capture-recapture data relating to dippers and compare different Bayesian model-fitting algorithms within WinBUGS.

  17. Bridging the Gap Between Quantum Chemistry and Classical Simulations for CO2 Capture

    Energy Technology Data Exchange (ETDEWEB)

    Gagliardi, Laura [Univ. of Minnesota, Minneapolis, MN (United States)

    2015-09-17

    We have developed a systematic procedure to generate transferable force fields to simulate the behavior of CO2 and other gases in open-metal-site metal organic frameworks using high-level quantum chemical calculations. Monte Carlo simulations based on an ab initio force field for CO2 in the Mg2(dobpdc) material have been employed to describe the interactions of CO2 with open metals. Our study has shed some light on the interpretation of thermodynamic data of flue gas in Mg2(dobpdc). This force field accurately describes the chemistry of the open metal sites, and is transferable to other structures.

  18. Integration of a Motion Capture System into a Spacecraft Simulator for Real-Time Attitude Control

    Science.gov (United States)

    2016-08-16

    Attitude Control * Benjamin L. Reifler University at Buffalo, Buffalo, New York 1st Lt Dylan R. Penn Air Force Research Laboratory, Kirtland Air Force...Base, New Mexico 16 August 2016 Abstract The Attitude Control System Proving Ground (ACSPG) is a three-degree-of-freedom spacecraft simulator mounted...unlimited. DISTRIBUTION A. Approved for public release: distribution unlimited. 1 Introduction The attitude determination and control subsystem (ADCS

  19. Theoretical simulation of CO2 capture in organic cage impregnated with polyoxometalates.

    Science.gov (United States)

    Gao, Jingyuan; Li, Wenliang; Zhang, Jingping

    2017-04-05

    To explore the adsorption and separation properties of CO2 in a novel material consisting of a series of polyoxometalates (POMs) impregnated within supramolecular porous catenane (shorted as SPC), grand canonical Monte Carlo (GCMC) simulations and ab initio calculations were used. GCMC simulations showed this impregnation can enhance CO2 /CH4 (or CO2 /N2 ) selectivity almost 30 times compared to the bare SPC due to the strong interaction of CO2 with the nPOMs@SPC structures. And, the loading of CO2 inhibits the adsorption of CH4 (or N2 ) as CO2 occupying the preferred adsorption sites. Furthermore, the effect of number, mass, and volume of POMs inserted in SPC on CO2 /CH4 (or CO2 /N2 ) selectivity over large pressure range was investigated in detail. Additionally, the accurate ab initio calculations further confirmed our GCMC simulations. As a result, the proposed nPOMs@SPC structures are promising candidates for CO2 /N2 and CO2 /CH4 separations. © 2017 Wiley Periodicals, Inc.

  20. Techniques and Simulation Models in Risk Management

    OpenAIRE

    Mirela GHEORGHE

    2012-01-01

    In the present paper, the scientific approach of the research starts from the theoretical framework of the simulation concept and then continues in the setting of the practical reality, thus providing simulation models for a broad range of inherent risks specific to any organization and simulation of those models, using the informatics instrument @Risk (Palisade). The reason behind this research lies in the need for simulation models that will allow the person in charge with decision taking i...

  1. Unpacking the mechanisms captured by a correlative species distribution model to improve predictions of climate refugia.

    Science.gov (United States)

    Briscoe, Natalie J; Kearney, Michael R; Taylor, Chris A; Wintle, Brendan A

    2016-07-01

    Climate refugia are regions that animals can retreat to, persist in and potentially then expand from under changing environmental conditions. Most forecasts of climate change refugia for species are based on correlative species distribution models (SDMs) using long-term climate averages, projected to future climate scenarios. Limitations of such methods include the need to extrapolate into novel environments and uncertainty regarding the extent to which proximate variables included in the model capture processes driving distribution limits (and thus can be assumed to provide reliable predictions under new conditions). These limitations are well documented; however, their impact on the quality of climate refugia predictions is difficult to quantify. Here, we develop a detailed bioenergetics model for the koala. It indicates that range limits are driven by heat-induced water stress, with the timing of rainfall and heat waves limiting the koala in the warmer parts of its range. We compare refugia predictions from the bioenergetics model with predictions from a suite of competing correlative SDMs under a range of future climate scenarios. SDMs were fitted using combinations of long-term climate and weather extremes variables, to test how well each set of predictions captures the knowledge embedded in the bioenergetics model. Correlative models produced broadly similar predictions to the bioenergetics model across much of the species' current range - with SDMs that included weather extremes showing highest congruence. However, predictions in some regions diverged significantly when projecting to future climates due to the breakdown in correlation between climate variables. We provide unique insight into the mechanisms driving koala distribution and illustrate the importance of subtle relationships between the timing of weather events, particularly rain relative to hot-spells, in driving species-climate relationships and distributions. By unpacking the mechanisms

  2. Bridging experiments, models and simulations

    DEFF Research Database (Denmark)

    Carusi, Annamaria; Burrage, Kevin; Rodríguez, Blanca

    2012-01-01

    Computational models in physiology often integrate functional and structural information from a large range of spatiotemporal scales from the ionic to the whole organ level. Their sophistication raises both expectations and skepticism concerning how computational methods can improve our understan...... that contributes to defining the specific aspects of cardiac electrophysiology the MSE system targets, rather than being only an external test, and that this is driven by advances in experimental and computational methods and the combination of both....... of biovariability; 2) testing and developing robust techniques and tools as a prerequisite to conducting physiological investigations; 3) defining and adopting standards to facilitate the interoperability of experiments, models, and simulations; 4) and understanding physiological validation as an iterative process...... understanding of living organisms and also how they can reduce, replace, and refine animal experiments. A fundamental requirement to fulfill these expectations and achieve the full potential of computational physiology is a clear understanding of what models represent and how they can be validated. The present...

  3. Using the Pharmacist Interaction Tracking Tool for Capturing Student-Patient Interactions in Direct and Simulated Patient Care Activities.

    Science.gov (United States)

    Hall, Deanne L; Schonder, Kristine S; Pater, Karen S; McGivney, Melissa S; Meyer, Susan M

    2016-08-25

    Objective. To create and implement a standardized data collection tool for capturing student-patient interactions in direct and simulated patient care activities. Design. Faculty members and students determined key elements, design, and an implementation plan for the tool, which was to be used by students across professional years to quantify numbers and types of interactions with patients for tracking student progression toward achievement of curricular outcomes. Assessment. During the 2013-2014 academic year, 27 778 entries were completed, with 17 767 (64%) advanced pharmacy practice experiences, 7272 (26%) introductory pharmacy practice experiences, and 2739 (10%) simulation. Direct patient care interactions occurred with 11 090 patients and 10 983 providers, with 14 252 drug-related problems identified. Data was used by students for their professional portfolios, by administrators for curricular assessment, and to student impact on patient care. Conclusion. The PITT Form enabled the collection of data from actual and simulated patient care activities, allowed for curricular assessment of activities across years, and was used by individual students.

  4. JPEG color barcode images analysis: A camera phone capture channel model with auto-focus

    Directory of Open Access Journals (Sweden)

    Keng T. Tan

    2009-12-01

    Full Text Available As camera phones have permeated into our everyday lives, two dimensional (2D barcode has attracted researchers and developers as a cost-effective ubiquitous computing tool. A variety of 2D barcodes and their applications have been developed. Often, only monochrome2D barcodes are used due to their robustness in an uncontrolled operating environment of camera phones. However, we are seeing an emerging use of color 2D barcodes for camera phones. Nonetheless, using a greater multitude of colors introduces errors that can negatively affect the robustness of barcode reading. This is especially true when developing a 2D barcode for camera phones which capture and store these barcode images in the baselineJPEG format. This paper presents one aspect of the errors introduced by such camera phones by modeling the camera phone capture channel for JPEG color barcode images wherein there is camera auto-focus.

  5. Use of spatial capture-recapture modeling and DNA data to estimate densities of elusive animals

    Science.gov (United States)

    Kery, Marc; Gardner, Beth; Stoeckle, Tabea; Weber, Darius; Royle, J. Andrew

    2011-01-01

    Assessment of abundance, survival, recruitment rates, and density (i.e., population assessment) is especially challenging for elusive species most in need of protection (e.g., rare carnivores). Individual identification methods, such as DNA sampling, provide ways of studying such species efficiently and noninvasively. Additionally, statistical methods that correct for undetected animals and account for locations where animals are captured are available to efficiently estimate density and other demographic parameters. We collected hair samples of European wildcat (Felis silvestris) from cheek-rub lure sticks, extracted DNA from the samples, and identified each animals' genotype. To estimate the density of wildcats, we used Bayesian inference in a spatial capture-recapture model. We used WinBUGS to fit a model that accounted for differences in detection probability among individuals and seasons and between two lure arrays. We detected 21 individual wildcats (including possible hybrids) 47 times. Wildcat density was estimated at 0.29/km2 (SE 0.06), and 95% of the activity of wildcats was estimated to occur within 1.83 km from their home-range center. Lures located systematically were associated with a greater number of detections than lures placed in a cell on the basis of expert opinion. Detection probability of individual cats was greatest in late March. Our model is a generalized linear mixed model; hence, it can be easily extended, for instance, to incorporate trap- and individual-level covariates. We believe that the combined use of noninvasive sampling techniques and spatial capture-recapture models will improve population assessments, especially for rare and elusive animals.

  6. Distributed simulation a model driven engineering approach

    CERN Document Server

    Topçu, Okan; Oğuztüzün, Halit; Yilmaz, Levent

    2016-01-01

    Backed by substantive case studies, the novel approach to software engineering for distributed simulation outlined in this text demonstrates the potent synergies between model-driven techniques, simulation, intelligent agents, and computer systems development.

  7. Benchmark simulation models, quo vadis?

    Science.gov (United States)

    Jeppsson, U; Alex, J; Batstone, D J; Benedetti, L; Comas, J; Copp, J B; Corominas, L; Flores-Alsina, X; Gernaey, K V; Nopens, I; Pons, M-N; Rodríguez-Roda, I; Rosen, C; Steyer, J-P; Vanrolleghem, P A; Volcke, E I P; Vrecko, D

    2013-01-01

    As the work of the IWA Task Group on Benchmarking of Control Strategies for wastewater treatment plants (WWTPs) is coming to an end, it is essential to disseminate the knowledge gained. For this reason, all authors of the IWA Scientific and Technical Report on benchmarking have come together to provide their insights, highlighting areas where knowledge may still be deficient and where new opportunities are emerging, and to propose potential avenues for future development and application of the general benchmarking framework and its associated tools. The paper focuses on the topics of temporal and spatial extension, process modifications within the WWTP, the realism of models, control strategy extensions and the potential for new evaluation tools within the existing benchmark system. We find that there are major opportunities for application within all of these areas, either from existing work already being done within the context of the benchmarking simulation models (BSMs) or applicable work in the wider literature. Of key importance is increasing capability, usability and transparency of the BSM package while avoiding unnecessary complexity.

  8. Practical enhancement factor model based on GM for multiple parallel reactions: Piperazine (PZ) CO2 capture

    DEFF Research Database (Denmark)

    Gaspar, Jozsef; Fosbøl, Philip Loldrup

    2017-01-01

    Reactive absorption is a key process for gas separation and purification and it is the main technology for CO2 capture. Thus, reliable and simple mathematical models for mass transfer rate calculation are essential. Models which apply to parallel interacting and non-interacting reactions, for all......, desorption and pinch conditions.In this work, we apply the GM model to multiple parallel reactions. We deduce the model for piperazine (PZ) CO2 capture and we validate it against wetted-wall column measurements using 2, 5 and 8 molal PZ for temperatures between 40 °C and 100 °C and CO2 loadings between 0.......23 and 0.41 mol CO2/2 mol PZ. We show that overall second order kinetics describes well the reaction between CO2 and PZ accounting for the carbamate and bicarbamate reactions. Here we prove the GM model for piperazine and MEA but we expect that this practical approach is applicable for various amines...

  9. Lotka-Volterra pairwise modeling fails to capture diverse pairwise microbial interactions.

    Science.gov (United States)

    Momeni, Babak; Xie, Li; Shou, Wenying

    2017-03-28

    Pairwise models are commonly used to describe many-species communities. In these models, an individual receives additive fitness effects from pairwise interactions with each species in the community ('additivity assumption'). All pairwise interactions are typically represented by a single equation where parameters reflect signs and strengths of fitness effects ('universality assumption'). Here, we show that a single equation fails to qualitatively capture diverse pairwise microbial interactions. We build mechanistic reference models for two microbial species engaging in commonly-found chemical-mediated interactions, and attempt to derive pairwise models. Different equations are appropriate depending on whether a mediator is consumable or reusable, whether an interaction is mediated by one or more mediators, and sometimes even on quantitative details of the community (e.g. relative fitness of the two species, initial conditions). Our results, combined with potential violation of the additivity assumption in many-species communities, suggest that pairwise modeling will often fail to predict microbial dynamics.

  10. Off-gas Adsorption Model and Simulation - OSPREY

    Energy Technology Data Exchange (ETDEWEB)

    Veronica J Rutledge

    2013-10-01

    The absence of industrial scale nuclear fuel reprocessing in the U.S. has precluded the necessary driver for developing the advanced simulation capability now prevalent in so many other countries. Thus, it is essential to model complex series of unit operations to simulate, understand, and predict inherent transient behavior. A capability of accurately simulating the dynamic behavior of advanced fuel cycle separation processes is expected to provide substantial cost savings and many technical benefits. To support this capability, a modeling effort focused on the off-gas treatment system of a used nuclear fuel recycling facility is in progress. The off-gas separation consists of a series of scrubbers and adsorption beds to capture constituents of interest. Dynamic models are being developed to simulate each unit operation involved so each unit operation can be used as a stand-alone model and in series with multiple others. Currently, an adsorption model has been developed within Multi-physics Object Oriented Simulation Environment (MOOSE) developed at the Idaho National Laboratory (INL). Off-gas Separation and REcoverY (OSPREY) models the adsorption of offgas constituents for dispersed plug flow in a packed bed under non-isothermal and non-isobaric conditions. Inputs to the model include gas composition, sorbent and column properties, equilibrium and kinetic data, and inlet conditions. The simulation outputs component concentrations along the column length as a function of time from which breakthrough data can be obtained. The breakthrough data can be used to determine bed capacity, which in turn can be used to size columns. In addition to concentration data, the model predicts temperature along the column length as a function of time and pressure drop along the column length. A description of the OSPREY model, results from krypton adsorption modeling and plans for modeling the behavior of iodine, xenon, and tritium will be discussed.

  11. Prey capture in zebrafish larvae serves as a model to study cognitive functions

    Directory of Open Access Journals (Sweden)

    Akira eMuto

    2013-06-01

    Full Text Available Prey capture in zebrafish larvae is an innate behavior which can be observed as early as 4 days post fertilization, the day when they start to swim. This simple behavior apparently involves several neural processes including visual perception, recognition, decision-making, and motor control, and, therefore, serves as a good model system to study cognitive functions underlying natural behaviors in vertebrates. Recent progresses in imaging techniques provided us with a unique opportunity to image neuronal activity in the brain of an intact fish in real-time while the fish perceives a natural prey, paramecium. By expanding this approach, it would be possible to image entire brain areas at a single cell resolution in real-time during prey capture, and identify neuronal circuits important for cognitive functions. Further, activation or inhibition of those neuronal circuits with recently developed optogenetic tools or neurotoxins should shed light on their roles. Thus, we will be able to explore the prey capture in zebrafish larvae more thoroughly at cellular levels, which should establish a basis of understanding of the cognitive function in vertebrates.

  12. RTK-Spec TRON: A Simulation Model of an ITRON Based RTOS Kernel in SystemC

    CERN Document Server

    Hassan, M Abdelsalam; Takeuchi, Yoshinori; Imai, Masaharu

    2011-01-01

    This paper presents the methodology and the modeling constructs we have developed to capture the real time aspects of RTOS simulation models in a System Level Design Language (SLDL) like SystemC. We describe these constructs and show how they are used to build a simulation model of an RTOS kernel targeting the $\\mu$-ITRON OS specification standard.

  13. Structured building model reduction toward parallel simulation

    Energy Technology Data Exchange (ETDEWEB)

    Dobbs, Justin R. [Cornell University; Hencey, Brondon M. [Cornell University

    2013-08-26

    Building energy model reduction exchanges accuracy for improved simulation speed by reducing the number of dynamical equations. Parallel computing aims to improve simulation times without loss of accuracy but is poorly utilized by contemporary simulators and is inherently limited by inter-processor communication. This paper bridges these disparate techniques to implement efficient parallel building thermal simulation. We begin with a survey of three structured reduction approaches that compares their performance to a leading unstructured method. We then use structured model reduction to find thermal clusters in the building energy model and allocate processing resources. Experimental results demonstrate faster simulation and low error without any interprocessor communication.

  14. Simulation and Modeling Methodologies, Technologies and Applications

    CERN Document Server

    Filipe, Joaquim; Kacprzyk, Janusz; Pina, Nuno

    2014-01-01

    This book includes extended and revised versions of a set of selected papers from the 2012 International Conference on Simulation and Modeling Methodologies, Technologies and Applications (SIMULTECH 2012) which was sponsored by the Institute for Systems and Technologies of Information, Control and Communication (INSTICC) and held in Rome, Italy. SIMULTECH 2012 was technically co-sponsored by the Society for Modeling & Simulation International (SCS), GDR I3, Lionphant Simulation, Simulation Team and IFIP and held in cooperation with AIS Special Interest Group of Modeling and Simulation (AIS SIGMAS) and the Movimento Italiano Modellazione e Simulazione (MIMOS).

  15. An introduction to enterprise modeling and simulation

    Energy Technology Data Exchange (ETDEWEB)

    Ostic, J.K.; Cannon, C.E. [Los Alamos National Lab., NM (United States). Technology Modeling and Analysis Group

    1996-09-01

    As part of an ongoing effort to continuously improve productivity, quality, and efficiency of both industry and Department of Energy enterprises, Los Alamos National Laboratory is investigating various manufacturing and business enterprise simulation methods. A number of enterprise simulation software models are being developed to enable engineering analysis of enterprise activities. In this document the authors define the scope of enterprise modeling and simulation efforts, and review recent work in enterprise simulation at Los Alamos National Laboratory as well as at other industrial, academic, and research institutions. References of enterprise modeling and simulation methods and a glossary of enterprise-related terms are provided.

  16. Role of Additives in Composite PEI/Oxide CO₂ Adsorbents: Enhancement in the Amine Efficiency of Supported PEI by PEG in CO₂ Capture from Simulated Ambient Air.

    Science.gov (United States)

    Sakwa-Novak, Miles A; Tan, Shuai; Jones, Christopher W

    2015-11-11

    Supported amines are promising candidate adsorbents for the removal of CO2 from flue gases and directly from ambient air. The incorporation of additives into polymeric amines such as poly(ethylenimine) (PEI) supported on mesoporous oxides is an effective strategy to improve the performance of the materials. Here, several practical aspects of this strategy are addressed with regards to direct air capture. The influence of three additives (CTAB, PEG200, PEG1000) was systematically explored under dry simulated air capture conditions (400 ppm of CO2, 30 °C). With SBA-15 as a model support for poly(ethylenimine) (PEI), the nature of the additive induced heterogeneities in the deposition of organic on the interior and exterior of the particles, an important consideration for future scale up to practical systems. The PEG200 additive increased the observed thermodynamic performance (∼60% increase in amine efficiency) of the adsorbents regardless of the PEI content, while the other molecules had less positive effects. A threshold PEG200/PEI value was identified at which the diffusional limitations of CO2 within the materials were nearly eliminated. The threshold PEG/PEI ratio may have physical origin in the interactions between PEI and PEG, as the optimal ratio corresponded to nearly equimolar OH/reactive (1°, 2°) amine ratios. The strategy is shown to be robust to the characteristics of the host support, as PEG200 improved the amine efficiency of PEI when supported on two varieties of mesoporous γ-alumina with PEI.

  17. Helium Reionization Simulations. I. Modeling Quasars as Radiation Sources

    CERN Document Server

    La Plante, Paul

    2015-01-01

    We introduce a new project to understand helium reionization using fully coupled $N$-body, hydrodynamics, and radiative transfer simulations. This project aims to capture correctly the thermal history of the intergalactic medium (IGM) as a result of reionization and make predictions about the Lyman-$\\alpha$ forest and baryon temperature-density relation. The dominant sources of radiation for this transition are quasars, so modeling the source population accurately is very important for making reliable predictions. In this first paper, we present a new method for populating dark matter halos with quasars. Our set of quasar models include two different light curves, a lightbulb (simple on/off) and symmetric exponential model, and luminosity-dependent quasar lifetimes. Our method self-consistently reproduces an input quasar luminosity function (QLF) given a halo catalog from an $N$-body simulation, and propagates quasars through the merger history of halo hosts. After calibrating quasar clustering using measurem...

  18. A physiological production model for cacao : results of model simulations

    NARCIS (Netherlands)

    Zuidema, P.A.; Leffelaar, P.A.

    2002-01-01

    CASE2 is a physiological model for cocoa (Theobroma cacao L.) growth and yield. This report introduces the CAcao Simulation Engine for water-limited production in a non-technical way and presents simulation results obtained with the model.

  19. A physiological production model for cacao : results of model simulations

    NARCIS (Netherlands)

    Zuidema, P.A.; Leffelaar, P.A.

    2002-01-01

    CASE2 is a physiological model for cocoa (Theobroma cacao L.) growth and yield. This report introduces the CAcao Simulation Engine for water-limited production in a non-technical way and presents simulation results obtained with the model.

  20. Complexity of chromatin folding is captured by the strings and binders switch model.

    Science.gov (United States)

    Barbieri, Mariano; Chotalia, Mita; Fraser, James; Lavitas, Liron-Mark; Dostie, Josée; Pombo, Ana; Nicodemi, Mario

    2012-10-02

    Chromatin has a complex spatial organization in the cell nucleus that serves vital functional purposes. A variety of chromatin folding conformations has been detected by single-cell imaging and chromosome conformation capture-based approaches. However, a unified quantitative framework describing spatial chromatin organization is still lacking. Here, we explore the "strings and binders switch" model to explain the origin and variety of chromatin behaviors that coexist and dynamically change within living cells. This simple polymer model recapitulates the scaling properties of chromatin folding reported experimentally in different cellular systems, the fractal state of chromatin, the processes of domain formation, and looping out. Additionally, the strings and binders switch model reproduces the recently proposed "fractal-globule" model, but only as one of many possible transient conformations.

  1. A granocentric model captures the statistical properties of monodisperse random packings

    CERN Document Server

    Newhall, Katherine A; Vanden-Eijnden, Eric; Brujic, Jasna

    2012-01-01

    We present a generalization of the granocentric model proposed in [Clusel et al., Nature, 2009, 460, 611615] that is capable of describing the local fluctuations inside not only polydisperse but also monodisperse packings of spheres. This minimal model does not take into account the relative particle positions, yet it captures positional disorder through local stochastic processes sampled by efficient Monte Carlo methods. The disorder is characterized by the distributions of local parameters, such as the number of neighbors and contacts, filled solid angle around a central particle and the cell volumes. The model predictions are in good agreement with our experimental data on monodisperse random close packings of PMMA particles. Moreover, the model can be used to predict the distributions of local fluctuations in any packing, as long as the average number of neighbors, contacts and the packing fraction are known. These distributions give a microscopic foundation to the statistical mechanics framework for jamm...

  2. Dynamic Modeling and Control Studies of a Two-Stage Bubbling Fluidized Bed Adsorber-Reactor for Solid-Sorbent CO{sub 2} Capture

    Energy Technology Data Exchange (ETDEWEB)

    Modekurti, Srinivasarao; Bhattacharyya, Debangsu; Zitney, Stephen E.

    2013-07-31

    A one-dimensional, non-isothermal, pressure-driven dynamic model has been developed for a two-stage bubbling fluidized bed (BFB) adsorber-reactor for solid-sorbent carbon dioxide (CO{sub 2}) capture using Aspen Custom Modeler® (ACM). The BFB model for the flow of gas through a continuous phase of downward moving solids considers three regions: emulsion, bubble, and cloud-wake. Both the upper and lower reactor stages are of overflow-type configuration, i.e., the solids leave from the top of each stage. In addition, dynamic models have been developed for the downcomer that transfers solids between the stages and the exit hopper that removes solids from the bottom of the bed. The models of all auxiliary equipment such as valves and gas distributor have been integrated with the main model of the two-stage adsorber reactor. Using the developed dynamic model, the transient responses of various process variables such as CO{sub 2} capture rate and flue gas outlet temperatures have been studied by simulating typical disturbances such as change in the temperature, flowrate, and composition of the incoming flue gas from pulverized coal-fired power plants. In control studies, the performance of a proportional-integral-derivative (PID) controller, feedback-augmented feedforward controller, and linear model predictive controller (LMPC) are evaluated for maintaining the overall CO{sub 2} capture rate at a desired level in the face of typical disturbances.

  3. Simulation modeling and analysis with Arena

    CERN Document Server

    Altiok, Tayfur

    2007-01-01

    Simulation Modeling and Analysis with Arena is a highly readable textbook which treats the essentials of the Monte Carlo discrete-event simulation methodology, and does so in the context of a popular Arena simulation environment.” It treats simulation modeling as an in-vitro laboratory that facilitates the understanding of complex systems and experimentation with what-if scenarios in order to estimate their performance metrics. The book contains chapters on the simulation modeling methodology and the underpinnings of discrete-event systems, as well as the relevant underlying probability, statistics, stochastic processes, input analysis, model validation and output analysis. All simulation-related concepts are illustrated in numerous Arena examples, encompassing production lines, manufacturing and inventory systems, transportation systems, and computer information systems in networked settings.· Introduces the concept of discrete event Monte Carlo simulation, the most commonly used methodology for modeli...

  4. Nonsmooth Modeling and Simulation for Switched Circuits

    CERN Document Server

    Acary, Vincent; Brogliato, Bernard

    2011-01-01

    "Nonsmooth Modeling and Simulation for Switched Circuits" concerns the modeling and the numerical simulation of switched circuits with the nonsmooth dynamical systems (NSDS) approach, using piecewise-linear and multivalued models of electronic devices like diodes, transistors, switches. Numerous examples (ranging from introductory academic circuits to various types of power converters) are analyzed and many simulation results obtained with the INRIA open-source SICONOS software package are presented. Comparisons with SPICE and hybrid methods demonstrate the power of the NSDS approach

  5. Juno model rheometry and simulation

    Science.gov (United States)

    Sampl, Manfred; Macher, Wolfgang; Oswald, Thomas; Plettemeier, Dirk; Rucker, Helmut O.; Kurth, William S.

    2016-10-01

    The experiment Waves aboard the Juno spacecraft, which will arrive at its target planet Jupiter in 2016, was devised to study the plasma and radio waves of the Jovian magnetosphere. We analyzed the Waves antennas, which consist of two nonparallel monopoles operated as a dipole. For this investigation we applied two independent methods: the experimental technique, rheometry, which is based on a downscaled model of the spacecraft to measure the antenna properties in an electrolytic tank and numerical simulations, based on commercial computer codes, from which the quantities of interest (antenna impedances and effective length vectors) are calculated. In this article we focus on the results for the low-frequency range up to about 4 MHz, where the antenna system is in the quasi-static regime. Our findings show that there is a significant deviation of the effective length vectors from the physical monopole directions, caused by the presence of the conducting spacecraft body. The effective axes of the antenna monopoles are offset from the mechanical axes by more than 30°, and effective lengths show a reduction to about 60% of the antenna rod lengths. The antennas' mutual capacitances are small compared to the self-capacitances, and the latter are almost the same for the two monopoles. The overall performance of the antennas in dipole configuration is very stable throughout the frequency range up to about 4-5 MHz and therefore can be regarded as the upper frequency bound below which the presented quasi-static results are applicable.

  6. Evaluation of a target region capture sequencing platform using monogenic diabetes as a study-model

    DEFF Research Database (Denmark)

    Gao, R.; Liu, Y. X.; Gjesing, A. P.;

    2014-01-01

    Background: Monogenic diabetes is a genetic disease often caused by mutations in genes involved in beta-cell function. Correct sub-categorization of the disease is a prerequisite for appropriate treatment and genetic counseling. Target-region capture sequencing is a combination of genomic region...... diabetes as a study-model. Results: The performance of the assay was evaluated in 70 patients carrying known disease causing mutations previously identified in HNF4A, GCK, HNF1A, HNF1B, INS, or KCNJ11. Target regions with a less than 20-fold sequencing depth were either introns or UTRs. When only...... of monogenic diabetes....

  7. Coiling of an elastic beam inside a disk: A model for spider-capture silk

    Science.gov (United States)

    Elettro, Hervé; Vollrath, Fritz; Antkowiak, Arnaud; Neukirch, Sébastien

    2015-10-01

    Motivated by recent experimental observations of capillary-induced spooling of fibers inside droplets both in spider capture silk and in synthetic systems, we investigate the behavior of a fiber packed in a drop. Using a simplified 2D model, we provide analytical predictions for the buckling threshold and the deep post-buckling asymptotic behavior. The threshold for spooling is found to be in particularly good agreement with experimental results. We further solve the Elastica equations for a fiber confined in a soft potential, and track the equilibrium paths using numerical continuation techniques. A wealth of different paths corresponding to different symmetries is uncovered, and their stability is finally discussed.

  8. USING COPULAS TO MODEL DEPENDENCE IN SIMULATION RISK ASSESSMENT

    Energy Technology Data Exchange (ETDEWEB)

    Dana L. Kelly

    2007-11-01

    Typical engineering systems in applications with high failure consequences such as nuclear reactor plants often employ redundancy and diversity of equipment in an effort to lower the probability of failure and therefore risk. However, it has long been recognized that dependencies exist in these redundant and diverse systems. Some dependencies, such as common sources of electrical power, are typically captured in the logic structure of the risk model. Others, usually referred to as intercomponent dependencies, are treated implicitly by introducing one or more statistical parameters into the model. Such common-cause failure models have limitations in a simulation environment. In addition, substantial subjectivity is associated with parameter estimation for these models. This paper describes an approach in which system performance is simulated by drawing samples from the joint distributions of dependent variables. The approach relies on the notion of a copula distribution, a notion which has been employed by the actuarial community for ten years or more, but which has seen only limited application in technological risk assessment. The paper also illustrates how equipment failure data can be used in a Bayesian framework to estimate the parameter values in the copula model. This approach avoids much of the subjectivity required to estimate parameters in traditional common-cause failure models. Simulation examples are presented for failures in time. The open-source software package R is used to perform the simulations. The open-source software package WinBUGS is used to perform the Bayesian inference via Markov chain Monte Carlo sampling.

  9. Network Modeling and Simulation A Practical Perspective

    CERN Document Server

    Guizani, Mohsen; Khan, Bilal

    2010-01-01

    Network Modeling and Simulation is a practical guide to using modeling and simulation to solve real-life problems. The authors give a comprehensive exposition of the core concepts in modeling and simulation, and then systematically address the many practical considerations faced by developers in modeling complex large-scale systems. The authors provide examples from computer and telecommunication networks and use these to illustrate the process of mapping generic simulation concepts to domain-specific problems in different industries and disciplines. Key features: Provides the tools and strate

  10. Effect of image capture device on the accuracy of black-box printer models

    Science.gov (United States)

    Youn, Jason; Sun, Jian; Ju, Yanling; Kashti, Tamar; Frank, Tal; Kella, Dror; Fischer, Mani; Ulichney, Robert; Adams, Guy; Allebach, Jan

    2014-01-01

    In the process of electrophotograpic (EP) printing, the deposition of toner to the printer-addressable pixel is greatly influenced by the neighboring pixels of the digital halftone. To account for these effects, printer models can either be embedded in the halftoning algorithm, or used to predict the printed halftone image at the input to an algorithm that is used to assess print quality. Most recently,1 we developed a series of six new models to accurately account for local neighborhood effects and the influence of a 45 x 45 neighborhood of pixels on the central printer-addressable pixel. We refer to all these models as black-box models, since they are based solely on measuring what is on the printed page, and do not incorporate any information about the marking process itself. In this paper, we will compare black-box models developed with three different capture devices: an Epson Expression 10000XL (Epson America, Inc., Long Beach, CA, USA) flatbed scanner operated at 2400 dpi with an active field of view of 309.88 mm x 436.88 mm, a QEA PIAS-II (QEA, Inc., Billerica, MA, USA) camera with resolution 7663.4 dpi and a field of view of 2.4 mm x 3.2 mm, and Dr. CID, a 1:1 magnification 3.35 micron true resolution Dyson Relay lens-based 3 Mpixel USB CMOS imaging device2 with resolution 7946.8 dpi and a field of view of 4.91 mm 6.55 mm developed at Hewlett-Packard Laboratories { Bristol. Our target printer is an HP Indigo 5000 Digital Press (HP Indigo, Ness Ziona, Israel). In this paper, we will compare the accuracy of the black-box model predictions of print microstructure using models trained from images captured with these three devices.

  11. A new flexible plug and play scheme for modeling, simulating, and predicting gastric emptying

    NARCIS (Netherlands)

    Krishnan, S.; Avesaat, M. van; Troost, F.J.; Hendriks, H.F.J.; Graaf, A.A. de

    2014-01-01

    In-silico models that attempt to capture and describe the physiological behavior of biological organisms, including humans, are intrinsically complex and time consuming to build and simulate in a computing environment. The level of detail of description incorporated in the model depends on the

  12. A new flexible plug and play scheme for modeling, simulating, and predicting gastric emptying

    NARCIS (Netherlands)

    Krishnan, S.; Avesaat, M. van; Troost, F.J.; Hendriks, H.F.J.; Graaf, A.A. de

    2014-01-01

    In-silico models that attempt to capture and describe the physiological behavior of biological organisms, including humans, are intrinsically complex and time consuming to build and simulate in a computing environment. The level of detail of description incorporated in the model depends on the knowl

  13. Capturing Thoughts, Capturing Minds?

    DEFF Research Database (Denmark)

    Nielsen, Janni

    2004-01-01

    Think Aloud is cost effective, promises access to the user's mind and is the applied usability technique. But 'keep talking' is difficult, besides, the multimodal interface is visual not verbal. Eye-tracking seems to get around the verbalisation problem. It captures the visual focus of attention...

  14. Multiscale modeling and simulation of microtubule–motor-protein assemblies

    Science.gov (United States)

    Gao, Tong; Blackwell, Robert; Glaser, Matthew A.; Betterton, M. D.; Shelley, Michael J.

    2016-01-01

    Microtubules and motor proteins self-organize into biologically important assemblies including the mitotic spindle and the centrosomal microtubule array. Outside of cells, microtubule-motor mixtures can form novel active liquid-crystalline materials driven out of equilibrium by adenosine triphosphate–consuming motor proteins. Microscopic motor activity causes polarity-dependent interactions between motor proteins and microtubules, but how these interactions yield larger-scale dynamical behavior such as complex flows and defect dynamics is not well understood. We develop a multiscale theory for microtubule-motor systems in which Brownian dynamics simulations of polar microtubules driven by motors are used to study microscopic organization and stresses created by motor-mediated microtubule interactions. We identify polarity-sorting and crosslink tether relaxation as two polar-specific sources of active destabilizing stress. We then develop a continuum Doi-Onsager model that captures polarity sorting and the hydrodynamic flows generated by these polar-specific active stresses. In simulations of active nematic flows on immersed surfaces, the active stresses drive turbulent flow dynamics and continuous generation and annihilation of disclination defects. The dynamics follow from two instabilities, and accounting for the immersed nature of the experiment yields unambiguous characteristic length and time scales. When turning off the hydrodynamics in the Doi-Onsager model, we capture formation of polar lanes as observed in the Brownian dynamics simulation. PMID:26764729

  15. Capturing recrystallization of metals with a multi-scale materials model

    Energy Technology Data Exchange (ETDEWEB)

    D. A. Hughes; D. J. Bammann; A. Godfrey; V. C. Prantil; E. A. Holm; M. A. Miodownik; D. C. Chrzan; M. T. Lusk

    2000-04-01

    The final report for a Laboratory Directed Research and Development project entitled, ``Capturing Recrystallization of Metals in a Multiscale Materials Model'' is presented. In this project, deformation and recrystallization processes have been followed experimentally and theoretically in order to incorporate essential mechanisms from the defect (dislocation) and grain size length scales. A nonlinear rotational gradient theory has been developed which enables the incorporation of microstructural parameters. The evolution of these parameters during deformation and recrystallization has been characterized qualitatively and quantitatively, applying various electron optic techniques ranging over several length scales. The theoretical and experimental framework developed is general. It has been exemplified by an application to recrystallization in single crystals and bicrystals of aluminum. The recrystallization process has been modeled using a 3-D model for the changes in key structural parameters during recrystallization.

  16. The knowledge-based economy modeled, measured, simulated

    CERN Document Server

    Leydesdorff, Loet

    2006-01-01

    "Challenging, theoretically rich yet anchored in detailed empirical analysis, Loet Leydesdorff's exploration of the dynamics of the knowledge-economy is a major contribution to the field. Drawing on his expertise in science and technology studies, systems theory, and his internationally respected work on the 'triple helix', the book provides a radically new modelling and simulation of knowledge systems, capturing the articulation of structure, communication, and agency therein. This work will be of immense interest to both theorists of the knowledge-economy and practitioners in science policy." Andrew Webster Science & Technology Studies, University of York, UK

  17. Generic solar photovoltaic system dynamic simulation model specification

    Energy Technology Data Exchange (ETDEWEB)

    Ellis, Abraham [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Behnke, Michael Robert [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Elliott, Ryan Thomas [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)

    2013-10-01

    This document is intended to serve as a specification for generic solar photovoltaic (PV) system positive-sequence dynamic models to be implemented by software developers and approved by the WECC MVWG for use in bulk system dynamic simulations in accordance with NERC MOD standards. Two specific dynamic models are included in the scope of this document. The first, a Central Station PV System model, is intended to capture the most important dynamic characteristics of large scale (> 10 MW) PV systems with a central Point of Interconnection (POI) at the transmission level. The second, a Distributed PV System model, is intended to represent an aggregation of smaller, distribution-connected systems that comprise a portion of a composite load that might be modeled at a transmission load bus.

  18. Adjusting multistate capture-recapture models for misclassification bias: manatee breeding proportions

    Science.gov (United States)

    Kendall, W.L.; Hines, J.E.; Nichols, J.D.

    2003-01-01

    Matrix population models are important tools for research and management of populations. Estimating the parameters of these models is an important step in applying them to real populations. Multistate capture-recapture methods have provided a useful means for estimating survival and parameters of transition between locations or life history states but have mostly relied on the assumption that the state occupied by each detected animal is known with certainty. Nevertheless, in some cases animals can be misclassified. Using multiple capture sessions within each period of interest, we developed a method that adjusts estimates of transition probabilities for bias due to misclassification. We applied this method to 10 years of sighting data for a population of Florida manatees (Trichechus manatus latirostris) in order to estimate the annual probability of transition from nonbreeding to breeding status. Some sighted females were unequivocally classified as breeders because they were clearly accompanied by a first-year calf. The remainder were classified, sometimes erroneously, as nonbreeders because an attendant first-year calf was not observed or was classified as more than one year old. We estimated a conditional breeding probability of 0.31 + 0.04 (estimate + 1 SE) when we ignored misclassification bias, and 0.61 + 0.09 when we accounted for misclassification.

  19. FBI Fingerprint Image Capture System High-Speed-Front-End throughput modeling

    Energy Technology Data Exchange (ETDEWEB)

    Rathke, P.M.

    1993-09-01

    The Federal Bureau of Investigation (FBI) has undertaken a major modernization effort called the Integrated Automated Fingerprint Identification System (IAFISS). This system will provide centralized identification services using automated fingerprint, subject descriptor, mugshot, and document processing. A high-speed Fingerprint Image Capture System (FICS) is under development as part of the IAFIS program. The FICS will capture digital and microfilm images of FBI fingerprint cards for input into a central database. One FICS design supports two front-end scanning subsystems, known as the High-Speed-Front-End (HSFE) and Low-Speed-Front-End, to supply image data to a common data processing subsystem. The production rate of the HSFE is critical to meeting the FBI`s fingerprint card processing schedule. A model of the HSFE has been developed to help identify the issues driving the production rate, assist in the development of component specifications, and guide the evolution of an operations plan. A description of the model development is given, the assumptions are presented, and some HSFE throughput analysis is performed.

  20. Capturing appearance

    Science.gov (United States)

    Rushmeier, Holly E.

    2005-01-01

    For computer graphics applications, capturing the appearance parameters of objects (reflectance, transmittance and small scale surface structures), is as important as capturing the overall shape. We briefly review recent approaches developed by the computer graphics community to solve this problem. Excellent results have been obtained by various researchers measuring spatially varying reflectance functions for some classes of objects. We will consider some challenges from two of the remaining problematic classes of objects. First we will describe our experience scanning and modeling the throne of Tutankhamen. The major difficulties in this case were that the base shape was a highly detailed non-convex geometry with complex topology, and the shape was covered by optically uncooperative gold and silver. Then we will discuss some observations from our ongoing project to scan and model historic buildings on the Yale campus. The major difficulties in this second case are quantity of data and the lack of control over acquisition conditions.

  1. VHDL simulation with access to transistor models

    Science.gov (United States)

    Gibson, J.

    1991-01-01

    Hardware description languages such as VHDL have evolved to aid in the design of systems with large numbers of elements and a wide range of electronic and logical abstractions. For high performance circuits, behavioral models may not be able to efficiently include enough detail to give designers confidence in a simulation's accuracy. One option is to provide a link between the VHDL environment and a transistor level simulation environment. The coupling of the Vantage Analysis Systems VHDL simulator and the NOVA simulator provides the combination of VHDL modeling and transistor modeling.

  2. Experiment and modeling of CO{sub 2} capture from flue gases at high temperature in a fluidized bed reactor with Ca-based sorbents

    Energy Technology Data Exchange (ETDEWEB)

    Fan Fang; Zhen-Shan Li; Ning-Sheng Cai [Tsinghua University, Beijing (China). Key Laboratory for Thermal Science and Power Engineering of the Ministry of Education (MOE)

    2009-01-15

    The cyclic CO{sub 2} capture and CaCO{sub 3} regeneration characteristics in a small fluidized bed reactor were experimentally investigated with limestone and dolomite sorbents. Kinetic rate constants for carbonation and calcination were determined using thermogravimetric analysis (TGA) data. Mathematical models developed to model the Ca-based sorbent multiple cycles of CO{sub 2} capture and calcination in the bubbling fluidized bed reactor agreed with the experimental data. The experimental and simulated results showed that the CO{sub 2} in flue gases could be absorbed efficiently by limestone and dolomite. The time for high-efficiency CO{sub 2} capture decreased with an increasing number of cycles because of the loss of sorbent activity, and the final CO{sub 2} capture efficiency remained nearly constant as the sorbent reached its final residual capture capacity. In a continuous carbonation and calcination system, corresponding to the sorbent activity loss, the carbonation kinetic rates of sorbent undergoing various cycles are different, and the carbonation kinetic rates of sorbent circulating N times in the carbonation/calcination cycles are also different because of the different residence time of sorbent in the carbonator. Therefore, the average carbonation rate was given based on the mass balance and exit age distribution for sorbent in the carbonator. The CO{sub 2} capture characteristics in a continuous carbonation/calcination system were predicted, taking into consideration the mass balance, sorbent circulation rate, sorbent activity loss, and average carbonation kinetic rate, to give useful information for the reactor design and operation of multiple carbonation/calcination reaction cycles. 27 refs., 15 figs., 1 tab.

  3. Modeling and Simulation of Low Voltage Arcs

    NARCIS (Netherlands)

    Ghezzi, L.; Balestrero, A.

    2010-01-01

    Modeling and Simulation of Low Voltage Arcs is an attempt to improve the physical understanding, mathematical modeling and numerical simulation of the electric arcs that are found during current interruptions in low voltage circuit breakers. An empirical description is gained by refined electrical

  4. Modeling and Simulation of Low Voltage Arcs

    NARCIS (Netherlands)

    Ghezzi, L.; Balestrero, A.

    2010-01-01

    Modeling and Simulation of Low Voltage Arcs is an attempt to improve the physical understanding, mathematical modeling and numerical simulation of the electric arcs that are found during current interruptions in low voltage circuit breakers. An empirical description is gained by refined electrical m

  5. Whole-building Hygrothermal Simulation Model

    DEFF Research Database (Denmark)

    Rode, Carsten; Grau, Karl

    2003-01-01

    An existing integrated simulation tool for dynamic thermal simulation of building was extended with a transient model for moisture release and uptake in building materials. Validation of the new model was begun with comparison against measurements in an outdoor test cell furnished with single mat...

  6. Kuang's Semi-Classical Formalism for Electron Capture Cross-Sections in Ion-Ion Collisions at Approximately to MeV/amu: Application to ENA Modeling

    Science.gov (United States)

    Barghouty, A. F.

    2012-01-01

    Recent discovery by STEREO A/B of energetic neutral hydrogen is spurring an interest and need for reliable estimates of electron capture cross sections at few MeVs per nucleon as well as for multi-electron ions. Required accuracy in such estimates necessitates detailed and involved quantum-mechanical calculations or expensive numerical simulations. For ENA modeling and similar purposes, a semi-classical approach offers a middle-ground approach. Kuang's semiclassical formalism to calculate electron-capture cross sections for single and multi-electron ions is an elegant and efficient method, but has so far been applied to limited and specific laboratory measurements and at somewhat lower energies. Our goals are to test and extend Kuang s method to all ion-atom and ion-ion collisions relevant to ENA modeling, including multi-electron ions and for K-shell to K-shell transitions.

  7. Analysis of capture-recapture models with individual covariates using data augmentation

    Science.gov (United States)

    Royle, J. Andrew

    2009-01-01

    I consider the analysis of capture-recapture models with individual covariates that influence detection probability. Bayesian analysis of the joint likelihood is carried out using a flexible data augmentation scheme that facilitates analysis by Markov chain Monte Carlo methods, and a simple and straightforward implementation in freely available software. This approach is applied to a study of meadow voles (Microtus pennsylvanicus) in which auxiliary data on a continuous covariate (body mass) are recorded, and it is thought that detection probability is related to body mass. In a second example, the model is applied to an aerial waterfowl survey in which a double-observer protocol is used. The fundamental unit of observation is the cluster of individual birds, and the size of the cluster (a discrete covariate) is used as a covariate on detection probability.

  8. Development of an integrated Monte Carlo model for glioblastoma multiforme treated with boron neutron capture therapy.

    Science.gov (United States)

    Moghaddasi, Leyla; Bezak, Eva

    2017-08-01

    Glioblastomas (GBM) are notorious for their high fatality rate. Boron Neutron Capture Therapy (BNCT) being a biochemically targeted type of radiotherapy is a potent modality for GBM. In the current work, a BNCT treatment modelling framework for GBM was developed. Optimal Clinical Target Volume (CTV) margins for GBM-BNCT and the BNCT efficacy have been investigated. The model integrated a cell-based dosimetry model, an in-house-developed epithermal neutron beam model and previously-developed Microscopic Extension Probability (MEP) model. The system was defined as a cubic ICRP-brain phantom divided into 20 μm side voxels. The corresponding (10)B concentrations in GBM and normal brain cells were applied. The in-silico model was irradiated with the epithermal neutron beam using 2 and 2.5 cm CTV margins. Results from the cell-based dosimetry and the MEP models were combined to calculate GBM cell survival fractions (SF) post BNCT and compared to x-ray radiotherapy (XRT) SFs. Compared to XRT, the SF within the beam decreased by five orders of magnitudes and the total SF was reduced three times following BNCT. CTV extension by 0.5 cm reduced the SF by additional (53.8 ± 0.3)%. In conclusion, BNCT results in a more efficient cell kill. The extension of the CTV margin, however, may not increase the treatment outcome significantly.

  9. Deconvoluting simulated metagenomes: the performance of hard- and soft- clustering algorithms applied to metagenomic chromosome conformation capture (3C

    Directory of Open Access Journals (Sweden)

    Matthew Z. DeMaere

    2016-11-01

    Full Text Available Background Chromosome conformation capture, coupled with high throughput DNA sequencing in protocols like Hi-C and 3C-seq, has been proposed as a viable means of generating data to resolve the genomes of microorganisms living in naturally occuring environments. Metagenomic Hi-C and 3C-seq datasets have begun to emerge, but the feasibility of resolving genomes when closely related organisms (strain-level diversity are present in the sample has not yet been systematically characterised. Methods We developed a computational simulation pipeline for metagenomic 3C and Hi-C sequencing to evaluate the accuracy of genomic reconstructions at, above, and below an operationally defined species boundary. We simulated datasets and measured accuracy over a wide range of parameters. Five clustering algorithms were evaluated (2 hard, 3 soft using an adaptation of the extended B-cubed validation measure. Results When all genomes in a sample are below 95% sequence identity, all of the tested clustering algorithms performed well. When sequence data contains genomes above 95% identity (our operational definition of strain-level diversity, a naive soft-clustering extension of the Louvain method achieves the highest performance. Discussion Previously, only hard-clustering algorithms have been applied to metagenomic 3C and Hi-C data, yet none of these perform well when strain-level diversity exists in a metagenomic sample. Our simple extension of the Louvain method performed the best in these scenarios, however, accuracy remained well below the levels observed for samples without strain-level diversity. Strain resolution is also highly dependent on the amount of available 3C sequence data, suggesting that depth of sequencing must be carefully considered during experimental design. Finally, there appears to be great scope to improve the accuracy of strain resolution through further algorithm development.

  10. Arctic Ocean Freshwater: How Robust are Model Simulations

    Science.gov (United States)

    Jahn, A.; Aksenov, Y.; deCuevas, B. A.; deSteur, L.; Haekkinen, S.; Hansen, E.; Herbaut, C.; Houssais, M.-N.; Karcher, M.; Kauker, F.; Lique, C.; Nguyen, A.; Pemberton, P.; Worthen, D.; Zhang, J.

    2012-01-01

    The Arctic freshwater (FW) has been the focus of many modeling studies, due to the potential impact of Arctic FW on the deep water formation in the North Atlantic. A comparison of the hindcasts from ten ocean-sea ice models shows that the simulation of the Arctic FW budget is quite different in the investigated models. While they agree on the general sink and source terms of the Arctic FW budget, the long-term means as well as the variability of the FW export vary among models. The best model-to-model agreement is found for the interannual and seasonal variability of the solid FW export and the solid FW storage, which also agree well with observations. For the interannual and seasonal variability of the liquid FW export, the agreement among models is better for the Canadian Arctic Archipelago (CAA) than for Fram Strait. The reason for this is that models are more consistent in simulating volume flux anomalies than salinity anomalies and volume-flux anomalies dominate the liquid FW export variability in the CAA but not in Fram Strait. The seasonal cycle of the liquid FW export generally shows a better agreement among models than the interannual variability, and compared to observations the models capture the seasonality of the liquid FW export rather well. In order to improve future simulations of the Arctic FW budget, the simulation of the salinity field needs to be improved, so that model results on the variability of the liquid FW export and storage become more robust.

  11. Kuang's Semi-Classical Formalism for Electron Capture Cross-Sections in Ion-Ion Collisions at few MeV's/nucleon: Application to ENA Modeling

    Science.gov (United States)

    Barghouty, A. F.

    2012-01-01

    Accurate estimates of electron-capture cross sections at energies relevant to energetic neutral atom (ENA) modeling (approx few MeV per nucleon) and for multi-electron ions must rely on first-principles approaches and/or detailed quantum-mechanical simulation of the collision process. Kuang's semi-classical approach offers a middle-ground, elegant and efficient way to arrive at these estimates. We shall present a sample application and current progress in applying and extending Kuang's formalism to ENA modeling.

  12. Stormwater Tank Performance: Design and Management Criteria for Capture Tanks Using a Continuous Simulation and a Semi-Probabilistic Analytical Approach

    Directory of Open Access Journals (Sweden)

    Flavio De Martino

    2013-10-01

    Full Text Available Stormwater tank performance significantly depends on management practices. This paper proposes a procedure to assess tank efficiency in terms of volume and pollutant concentration using four different capture tank management protocols. The comparison of the efficiency results reveals that, as expected, a combined bypass—stormwater tank system achieves better results than a tank alone. The management practices tested for the tank-only systems provide notably different efficiency results. The practice of immediately emptying after the end of the event exhibits significant levels of efficiency and operational advantages. All other configurations exhibit either significant operational problems or very low performances. The continuous simulation and semi-probabilistic approach for the best tank management practice are compared. The semi-probabilistic approach is based on a Weibull probabilistic model of the main characteristics of the rainfall process. Following this approach, efficiency indexes were established. The comparison with continuous simulations shows the reliability of the probabilistic approach even if this last is certainly very site sensitive.

  13. A Biomechanical Model of the Scapulothoracic Joint to Accurately Capture Scapular Kinematics during Shoulder Movements

    Science.gov (United States)

    Seth, Ajay; Matias, Ricardo; Veloso, António P.; Delp, Scott L.

    2016-01-01

    The complexity of shoulder mechanics combined with the movement of skin relative to the scapula makes it difficult to measure shoulder kinematics with sufficient accuracy to distinguish between symptomatic and asymptomatic individuals. Multibody skeletal models can improve motion capture accuracy by reducing the space of possible joint movements, and models are used widely to improve measurement of lower limb kinematics. In this study, we developed a rigid-body model of a scapulothoracic joint to describe the kinematics of the scapula relative to the thorax. This model describes scapular kinematics with four degrees of freedom: 1) elevation and 2) abduction of the scapula on an ellipsoidal thoracic surface, 3) upward rotation of the scapula normal to the thoracic surface, and 4) internal rotation of the scapula to lift the medial border of the scapula off the surface of the thorax. The surface dimensions and joint axes can be customized to match an individual’s anthropometry. We compared the model to “gold standard” bone-pin kinematics collected during three shoulder tasks and found modeled scapular kinematics to be accurate to within 2mm root-mean-squared error for individual bone-pin markers across all markers and movement tasks. As an additional test, we added random and systematic noise to the bone-pin marker data and found that the model reduced kinematic variability due to noise by 65% compared to Euler angles computed without the model. Our scapulothoracic joint model can be used for inverse and forward dynamics analyses and to compute joint reaction loads. The computational performance of the scapulothoracic joint model is well suited for real-time applications; it is freely available for use with OpenSim 3.2, and is customizable and usable with other OpenSim models. PMID:26734761

  14. A Biomechanical Model of the Scapulothoracic Joint to Accurately Capture Scapular Kinematics during Shoulder Movements.

    Science.gov (United States)

    Seth, Ajay; Matias, Ricardo; Veloso, António P; Delp, Scott L

    2016-01-01

    The complexity of shoulder mechanics combined with the movement of skin relative to the scapula makes it difficult to measure shoulder kinematics with sufficient accuracy to distinguish between symptomatic and asymptomatic individuals. Multibody skeletal models can improve motion capture accuracy by reducing the space of possible joint movements, and models are used widely to improve measurement of lower limb kinematics. In this study, we developed a rigid-body model of a scapulothoracic joint to describe the kinematics of the scapula relative to the thorax. This model describes scapular kinematics with four degrees of freedom: 1) elevation and 2) abduction of the scapula on an ellipsoidal thoracic surface, 3) upward rotation of the scapula normal to the thoracic surface, and 4) internal rotation of the scapula to lift the medial border of the scapula off the surface of the thorax. The surface dimensions and joint axes can be customized to match an individual's anthropometry. We compared the model to "gold standard" bone-pin kinematics collected during three shoulder tasks and found modeled scapular kinematics to be accurate to within 2 mm root-mean-squared error for individual bone-pin markers across all markers and movement tasks. As an additional test, we added random and systematic noise to the bone-pin marker data and found that the model reduced kinematic variability due to noise by 65% compared to Euler angles computed without the model. Our scapulothoracic joint model can be used for inverse and forward dynamics analyses and to compute joint reaction loads. The computational performance of the scapulothoracic joint model is well suited for real-time applications; it is freely available for use with OpenSim 3.2, and is customizable and usable with other OpenSim models.

  15. A Biomechanical Model of the Scapulothoracic Joint to Accurately Capture Scapular Kinematics during Shoulder Movements.

    Directory of Open Access Journals (Sweden)

    Ajay Seth

    Full Text Available The complexity of shoulder mechanics combined with the movement of skin relative to the scapula makes it difficult to measure shoulder kinematics with sufficient accuracy to distinguish between symptomatic and asymptomatic individuals. Multibody skeletal models can improve motion capture accuracy by reducing the space of possible joint movements, and models are used widely to improve measurement of lower limb kinematics. In this study, we developed a rigid-body model of a scapulothoracic joint to describe the kinematics of the scapula relative to the thorax. This model describes scapular kinematics with four degrees of freedom: 1 elevation and 2 abduction of the scapula on an ellipsoidal thoracic surface, 3 upward rotation of the scapula normal to the thoracic surface, and 4 internal rotation of the scapula to lift the medial border of the scapula off the surface of the thorax. The surface dimensions and joint axes can be customized to match an individual's anthropometry. We compared the model to "gold standard" bone-pin kinematics collected during three shoulder tasks and found modeled scapular kinematics to be accurate to within 2 mm root-mean-squared error for individual bone-pin markers across all markers and movement tasks. As an additional test, we added random and systematic noise to the bone-pin marker data and found that the model reduced kinematic variability due to noise by 65% compared to Euler angles computed without the model. Our scapulothoracic joint model can be used for inverse and forward dynamics analyses and to compute joint reaction loads. The computational performance of the scapulothoracic joint model is well suited for real-time applications; it is freely available for use with OpenSim 3.2, and is customizable and usable with other OpenSim models.

  16. A model to capture and manage tacit knowledge using a multiagent system

    Science.gov (United States)

    Paolino, Lilyam; Paggi, Horacio; Alonso, Fernando; López, Genoveva

    2014-10-01

    This article presents a model to capture and register business tacit knowledge belonging to different sources, using an expert multiagent system which enables the entry of incidences and captures the tacit knowledge which could fix them. This knowledge and their sources are evaluated through the application of trustworthy algorithms that lead to the registration of the data base and the best of each of them. Through its intelligent software agents, this system interacts with the administrator, users, with the knowledge sources and with all the practice communities which might exist in the business world. The sources as well as the knowledge are constantly evaluated, before being registered and also after that, in order to decide the staying or modification of its original weighting. If there is the possibility of better, new knowledge are registered through the old ones. This is also part of an investigation being carried out which refers to knowledge management methodologies in order to manage tacit business knowledge so as to make the business competitiveness easier and leading to innovation learning.

  17. Radiative capture reaction for $^{17}$Ne formation within a full three-body model

    CERN Document Server

    Casal, J; de Diego, R; Arias, J M; Rodríguez-Gallardo, M

    2016-01-01

    Background: The breakout from the hot CNO cycles can trigger the rp-process in type I X-ray bursts. In this environment, a competition between $^{15}\\text{O}(\\alpha,\\gamma){^{19}\\text{Ne}}$ and the two-proton capture reaction $^{15}\\text{O}(2p,\\gamma){^{17}\\text{Ne}}$ is expected. Purpose: Determine the three-body radiative capture reaction rate for ${^{17}\\text{Ne}}$ formation including sequential and direct, resonant and non-resonant contributions on an equal footing. Method: Two different discretization methods have been applied to generate $^{17}$Ne states in a full three-body model: the analytical transformed harmonic oscillator method and the hyperspherical adiabatic expansion method. The binary $p$--$^{15}$O interation has been adjusted to reproduce the known spectrum of the unbound $^{16}$F nucleus. The dominant E1 contributions to the $^{15}\\text{O}(2p,\\gamma){^{17}\\text{Ne}}$ reaction rate have been calculated from the inverse photodissociation process. Results: Three-body calculations provide a rel...

  18. Whole-building Hygrothermal Simulation Model

    DEFF Research Database (Denmark)

    Rode, Carsten; Grau, Karl

    2003-01-01

    An existing integrated simulation tool for dynamic thermal simulation of building was extended with a transient model for moisture release and uptake in building materials. Validation of the new model was begun with comparison against measurements in an outdoor test cell furnished with single...... materials. Almost quasi-steady, cyclic experiments were used to compare the indoor humidity variation and the numerical results of the integrated simulation tool with the new moisture model. Except for the case with chipboard as furnishing, the predictions of indoor humidity with the detailed model were...

  19. Simulation model of metallurgical production management

    Directory of Open Access Journals (Sweden)

    P. Šnapka

    2013-07-01

    Full Text Available This article is focused to the problems of the metallurgical production process intensification. The aim is the explaining of simulation model which presents metallurgical production management system adequated to new requirements. The knowledge of a dynamic behavior and features of metallurgical production system and its management are needed to this model creation. Characteristics which determine the dynamics of metallurgical production process are characterized. Simulation model is structured as functional blocks and their linkages with regard to organizational and temporal hierarchy of their actions. The creation of presented simulation model is based on theoretical findings of regulation, hierarchical systems and optimization.

  20. Mathematical modeling and stochastic simulation of soft materials

    Science.gov (United States)

    Zeng, Yun

    Soft materials are all around us; they may appear as consumer products, foods, or biological materials. The interest in studying the properties of soft materials both experimentally and theoretically has steadily increased due to their wide range of industrial applications. One example of a soft material is wormlike micellar solutions. Depending on the temperature and composition, these solvent-surfactant-salt mixtures may exhibit close to mono-exponential or, alternatively, power-law or stretched-exponential stress decay. Of particular interest to this thesis is the development of stochastic models that can capture the stress relaxation behavior of such materials in the small strain limit, which is non-exponential in time as opposed to exponential. Continuous time random walk (CTRW) or subordinated Langevin processes are utilized to model systems exhibiting non-exponential relaxation behavior or anomalous diffusion. Stochastic simulations using the CTRW approach or the subordination method are carried out in this thesis for one-dimensional systems in which the probability density distribution of particle positions is described by a fractional Fokker-Planck equation (FFPE). The equivalence of the CTRW simulation and the subordination simulation with that of the FFPE is analyzed through the simulation of an ensemble of particle trajectories. The simulated particle dynamics suggest that CTRW processes or subordinated Langevin dynamics can be included in soft material mesoscale dynamics to capture the anomalous transport. To model the non-exponential stress relaxation dynamics of soft gel systems (three-dimensional fluids), stochastic models are simulated using transient network theory as developed and combined with the CTRW and subordinated Langevin processes. This approach enables us to connect the microstructural dynamics of certain soft gel-like materials with macroscale experimental observations by examining the material properties under homogeneous shear flow

  1. MCNP{trademark} simulations for identifying environmental contaminants using prompt gamma-rays from thermal neutron capture reactions

    Energy Technology Data Exchange (ETDEWEB)

    Frankle, S.C.; Conaway, J.G.

    1996-12-31

    The primary purposes of the Multispectral Neutron Logging Project, (MSN Project, funded by the U.S. Department of Energy), were to assess the effectiveness of existing neutron- induced spectral gamma-ray logging techniques for identifying environmental contaminants along boreholes, to further improve the technology, and to transfer that technology to industry. Using a pulsed neutron source with a high-resolution gamma-ray detector, spectra from thermal neutron capture reactions may be used to identify contaminants in the borehole environment. Direct borehole measurements such as this complement physical sampling and are useful in environmental restoration projects where characterization of contaminated sites is required and long-term monitoring may be needed for many years following cleanup or stabilization. In the MSN Project, a prototype logging instrument was designed which incorporated a pulsed 14-MeV neutron source and HPGe detector. Experimental measurements to determine minimum detection thresholds with the prototype instrument were conducted in the variable-contaminant test model for Cl, Cd, Sm, Gd, and Hg. We benchmarked an enhanced version of the Monte Carlo N-Particle computer code MCNP{trademark} using experimental data for Cl provide by our collaborators and experimental data from the variable-contaminant test model. MCNP was then used to estimate detection thresholds for the other contaminants used in the variable-contaminant model with the goal of validating the use of MCNP to estimate detection thresholds for many other contaminants that were not measured.

  2. Simulation modeling for the health care manager.

    Science.gov (United States)

    Kennedy, Michael H

    2009-01-01

    This article addresses the use of simulation software to solve administrative problems faced by health care managers. Spreadsheet add-ins, process simulation software, and discrete event simulation software are available at a range of costs and complexity. All use the Monte Carlo method to realistically integrate probability distributions into models of the health care environment. Problems typically addressed by health care simulation modeling are facility planning, resource allocation, staffing, patient flow and wait time, routing and transportation, supply chain management, and process improvement.

  3. Warehouse Simulation Through Model Configuration

    NARCIS (Netherlands)

    Verriet, J.H.; Hamberg, R.; Caarls, J.; Wijngaarden, B. van

    2013-01-01

    The pre-build development of warehouse systems leads from a specific customer request to a specific customer quotation. This involves a process of configuring a warehouse system using a sequence of steps that contain increasingly more details. Simulation is a helpful tool in analyzing warehouse desi

  4. Modeling and Simulation of Matrix Converter

    DEFF Research Database (Denmark)

    Liu, Fu-rong; Klumpner, Christian; Blaabjerg, Frede

    2005-01-01

    This paper discusses the modeling and simulation of matrix converter. Two models of matrix converter are presented: one is based on indirect space vector modulation and the other is based on power balance equation. The basis of these two models is• given and the process on modeling is introduced...

  5. Quantum simulation of the t- J model

    Science.gov (United States)

    Yamaguchi, Fumiko; Yamamoto, Yoshihisa

    2002-12-01

    Computer simulation of a many-particle quantum system is bound to reach the inevitable limits of its ability as the system size increases. The primary reason for this is that the memory size used in a classical simulator grows polynomially whereas the Hilbert space of the quantum system does so exponentially. Replacing the classical simulator by a quantum simulator would be an effective method of surmounting this obstacle. The prevailing techniques for simulating quantum systems on a quantum computer have been developed for purposes of computing numerical algorithms designed to obtain approximate physical quantities of interest. The method suggested here requires no numerical algorithms; it is a direct isomorphic translation between a quantum simulator and the quantum system to be simulated. In the quantum simulator, physical parameters of the system, which are the fixed parameters of the simulated quantum system, are under the control of the experimenter. A method of simulating a model for high-temperature superconducting oxides, the t- J model, by optical control, as an example of such a quantum simulation, is presented.

  6. A capture-recapture survival analysis model for radio-tagged animals

    Science.gov (United States)

    Pollock, K.H.; Bunck, C.M.; Winterstein, S.R.; Chen, C.-L.; North, P.M.; Nichols, J.D.

    1995-01-01

    In recent years, survival analysis of radio-tagged animals has developed using methods based on the Kaplan-Meier method used in medical and engineering applications (Pollock et al., 1989a,b). An important assumption of this approach is that all tagged animals with a functioning radio can be relocated at each sampling time with probability 1. This assumption may not always be reasonable in practice. In this paper, we show how a general capture-recapture model can be derived which allows for some probability (less than one) for animals to be relocated. This model is not simply a Jolly-Seber model because it is possible to relocate both dead and live animals, unlike when traditional tagging is used. The model can also be viewed as a generalization of the Kaplan-Meier procedure, thus linking the Jolly-Seber and Kaplan-Meier approaches to survival estimation. We present maximum likelihood estimators and discuss testing between submodels. We also discuss model assumptions and their validity in practice. An example is presented based on canvasback data collected by G. M. Haramis of Patuxent Wildlife Research Center, Laurel, Maryland, USA.

  7. Lotka-Volterra pairwise modeling fails to capture diverse pairwise microbial interactions

    Science.gov (United States)

    Momeni, Babak; Xie, Li; Shou, Wenying

    2017-01-01

    Pairwise models are commonly used to describe many-species communities. In these models, an individual receives additive fitness effects from pairwise interactions with each species in the community ('additivity assumption'). All pairwise interactions are typically represented by a single equation where parameters reflect signs and strengths of fitness effects ('universality assumption'). Here, we show that a single equation fails to qualitatively capture diverse pairwise microbial interactions. We build mechanistic reference models for two microbial species engaging in commonly-found chemical-mediated interactions, and attempt to derive pairwise models. Different equations are appropriate depending on whether a mediator is consumable or reusable, whether an interaction is mediated by one or more mediators, and sometimes even on quantitative details of the community (e.g. relative fitness of the two species, initial conditions). Our results, combined with potential violation of the additivity assumption in many-species communities, suggest that pairwise modeling will often fail to predict microbial dynamics. DOI: http://dx.doi.org/10.7554/eLife.25051.001 PMID:28350295

  8. CAUSA - An Environment For Modeling And Simulation

    Science.gov (United States)

    Dilger, Werner; Moeller, Juergen

    1989-03-01

    CAUSA is an environment for modeling and simulation of dynamic systems on a quantitative level. The environment provides a conceptual framework including primitives like objects, processes and causal dependencies which allow the modeling of a broad class of complex systems. The facility of simulation allows the quantitative and qualitative inspection and empirical investigation of the behavior of the modeled system. CAUSA is implemented in Knowledge-Craft and runs on a Symbolics 3640.

  9. Modeling and Simulation of Matrix Converter

    DEFF Research Database (Denmark)

    Liu, Fu-rong; Klumpner, Christian; Blaabjerg, Frede

    2005-01-01

    This paper discusses the modeling and simulation of matrix converter. Two models of matrix converter are presented: one is based on indirect space vector modulation and the other is based on power balance equation. The basis of these two models is• given and the process on modeling is introduced...... in details. The results of simulations developed for different researches reveal that different mdel may be suitable for different purpose, thus the model should be chosen different carefully. Some details and tricks in modeling are also introduced which give a reference for further research....

  10. Simulation-based Manufacturing System Modeling

    Institute of Scientific and Technical Information of China (English)

    卫东; 金烨; 范秀敏; 严隽琪

    2003-01-01

    In recent years, computer simulation appears to be very advantageous technique for researching the resource-constrained manufacturing system. This paper presents an object-oriented simulation modeling method, which combines the merits of traditional methods such as IDEF0 and Petri Net. In this paper, a four-layer-one-angel hierarchical modeling framework based on OOP is defined. And the modeling description of these layers is expounded, such as: hybrid production control modeling and human resource dispatch modeling. To validate the modeling method, a case study of an auto-product line in a motor manufacturing company has been carried out.

  11. Modeling and parametric analysis of hollow fiber membrane system for carbon capture from multicomponent flue gas

    KAUST Repository

    Khalilpour, Rajab

    2011-08-12

    The modeling and optimal design/operation of gas membranes for postcombustion carbon capture (PCC) is presented. A systematic methodology is presented for analysis of membrane systems considering multicomponent flue gas with CO 2 as target component. Simplifying assumptions is avoided by namely multicomponent flue gas represented by CO 2/N 2 binary mixture or considering the co/countercurrent flow pattern of hollow-fiber membrane system as mixed flow. Optimal regions of flue gas pressures and membrane area were found within which a technoeconomical process system design could be carried out. High selectivity was found to not necessarily have notable impact on PCC membrane performance, rather, a medium selectivity combined with medium or high permeance could be more advantageous. © 2011 American Institute of Chemical Engineers (AIChE).

  12. Model-Based Reinforcement of Kinect Depth Data for Human Motion Capture Applications

    Directory of Open Access Journals (Sweden)

    Andreas Skiadopoulos

    2013-07-01

    Full Text Available Motion capture systems have recently experienced a strong evolution. New cheap depth sensors and open source frameworks, such as OpenNI, allow for perceiving human motion on-line without using invasive systems. However, these proposals do not evaluate the validity of the obtained poses. This paper addresses this issue using a model-based pose generator to complement the OpenNI human tracker. The proposed system enforces kinematics constraints, eliminates odd poses and filters sensor noise, while learning the real dimensions of the performer’s body. The system is composed by a PrimeSense sensor, an OpenNI tracker and a kinematics-based filter and has been extensively tested. Experiments show that the proposed system improves pure OpenNI results at a very low computational cost.

  13. Description of the proton and neutron radiative capture reactions in the Gamow shell model

    CERN Document Server

    Fossez, K; Płoszajczak, M; Jaganathen, Y

    2015-01-01

    We formulate the Gamow shell model (GSM) in coupled-channel (CC) representation for the description of proton/neutron radiative capture reactions and present the first application of this new formalism for the calculation of cross-sections in mirror reactions 7Be(p,gamma)8B and 7Li(n,gamma)8Li. The GSM-CC formalism is applied to a translationally-invariant Hamiltonian with an effective finite-range two-body interaction. Reactions channels are built by GSM wave functions for the ground state 3/2- and the first excited state 1/2- of 7Be/7Li and the proton/neutron wave function expanded in different partial waves.

  14. Single-strand recombination signal sequence nicks in vivo: evidence for a capture model of synapsis.

    Science.gov (United States)

    Curry, John D; Geier, Jamie K; Schlissel, Mark S

    2005-12-01

    Variable (diversity) joining (V(D)J) recombination is initiated by the introduction of single-strand DNA breaks (nicks) at recombination signal sequences (RSSs). The importance and fate of these RSS nicks for the regulation of the V(D)J rearrangement and their potential contribution to genomic instability are poorly understood. Using two new methodologies, we were able to detect and quantify specific RSS nicks introduced into genomic DNA by incubation with recombination-activating gene proteins in vitro. In vivo, however, we found that nicks mediated by recombination-activating gene (RAG) proteins were detectable only in gene segments associated with RSSs containing 12-base pair spacers but not in those containing 23-base pair spacers. These data support a model of capture rather than synapsis for pairwise RSS cleavage during V(D)J recombination.

  15. Multiscale Model Approach for Magnetization Dynamics Simulations

    CERN Document Server

    De Lucia, Andrea; Tretiakov, Oleg A; Kläui, Mathias

    2016-01-01

    Simulations of magnetization dynamics in a multiscale environment enable rapid evaluation of the Landau-Lifshitz-Gilbert equation in a mesoscopic sample with nanoscopic accuracy in areas where such accuracy is required. We have developed a multiscale magnetization dynamics simulation approach that can be applied to large systems with spin structures that vary locally on small length scales. To implement this, the conventional micromagnetic simulation framework has been expanded to include a multiscale solving routine. The software selectively simulates different regions of a ferromagnetic sample according to the spin structures located within in order to employ a suitable discretization and use either a micromagnetic or an atomistic model. To demonstrate the validity of the multiscale approach, we simulate the spin wave transmission across the regions simulated with the two different models and different discretizations. We find that the interface between the regions is fully transparent for spin waves with f...

  16. Radiative capture reaction for 17Ne formation within a full three-body model

    Science.gov (United States)

    Casal, J.; Garrido, E.; de Diego, R.; Arias, J. M.; Rodríguez-Gallardo, M.

    2016-11-01

    Background: The breakout from the hot Carbon-Nitrogen-Oxigen (CNO) cycles can trigger the rp-process in type I x-ray bursts. In this environment, a competition between 15O(α ,γ )19Ne and the two-proton capture reaction 15O(2 p ,γ )17Ne is expected. Purpose: Determine the three-body radiative capture reaction rate for 17Ne formation including sequential and direct, resonant and nonresonant contributions on an equal footing. Method: Two different discretization methods have been applied to generate 17Ne states in a full three-body model: the analytical transformed harmonic oscillator method and the hyperspherical adiabatic expansion method. The binary p -15O interaction has been adjusted to reproduce the known spectrum of the unbound 16F nucleus. The dominant E 1 contributions to the 15O(2 p ,γ )17Ne reaction rate have been calculated from the inverse photodissociation process. Results: Three-body calculations provide a reliable description of 17Ne states. The agreement with the available experimental data on 17Ne is discussed. It is shown that the 15O(2 p ,γ )17Ne reaction rates computed within the two methods agree in a broad range of temperatures. The present calculations are compared with a previous theoretical estimation of the reaction rate. Conclusions: It is found that the full three-body model provides a reaction rate several orders of magnitude larger than the only previous estimation. The implications for the rp-process in type I x-ray bursts should be investigated.

  17. Systematic modelling and simulation of refrigeration systems

    DEFF Research Database (Denmark)

    Rasmussen, Bjarne D.; Jakobsen, Arne

    1998-01-01

    The task of developing a simulation model of a refrigeration system can be very difficult and time consuming. In order for this process to be effective, a systematic method for developing the system model is required. This method should aim at guiding the developer to clarify the purpose of the s......The task of developing a simulation model of a refrigeration system can be very difficult and time consuming. In order for this process to be effective, a systematic method for developing the system model is required. This method should aim at guiding the developer to clarify the purpose...... of the simulation, to select appropriate component models and to set up the equations in a well-arranged way. In this paper the outline of such a method is proposed and examples showing the use of this method for simulation of refrigeration systems are given....

  18. Capture of Trojans by Jumping Jupiter

    CERN Document Server

    Nesvorny, David; Morbidelli, Alessandro

    2013-01-01

    Jupiter Trojans are thought to be survivors of a much larger population of planetesimals that existed in the planetary region when planets formed. They can provide important constraints on the mass and properties of the planetesimal disk, and its dispersal during planet migration. Here we tested a possibility that the Trojans were captured during the early dynamical instability among the outer planets (aka the Nice model), when the semimajor axis of Jupiter was changing as a result of scattering encounters with an ice giant. The capture occurs in this model when Jupiter's orbit and its Lagrange points become radially displaced in a scattering event and fall into a region populated by planetesimals (that previously evolved from their natal transplanetary disk to ~5 AU during the instability). Our numerical simulations of the new capture model, hereafter jump capture, satisfactorily reproduce the orbital distribution of the Trojans and their total mass. The jump capture is potentially capable of explaining the ...

  19. Software-Engineering Process Simulation (SEPS) model

    Science.gov (United States)

    Lin, C. Y.; Abdel-Hamid, T.; Sherif, J. S.

    1992-01-01

    The Software Engineering Process Simulation (SEPS) model is described which was developed at JPL. SEPS is a dynamic simulation model of the software project development process. It uses the feedback principles of system dynamics to simulate the dynamic interactions among various software life cycle development activities and management decision making processes. The model is designed to be a planning tool to examine tradeoffs of cost, schedule, and functionality, and to test the implications of different managerial policies on a project's outcome. Furthermore, SEPS will enable software managers to gain a better understanding of the dynamics of software project development and perform postmodern assessments.

  20. Systematic modelling and simulation of refrigeration systems

    DEFF Research Database (Denmark)

    Rasmussen, Bjarne D.; Jakobsen, Arne

    1998-01-01

    The task of developing a simulation model of a refrigeration system can be very difficult and time consuming. In order for this process to be effective, a systematic method for developing the system model is required. This method should aim at guiding the developer to clarify the purpose...... of the simulation, to select appropriate component models and to set up the equations in a well-arranged way. In this paper the outline of such a method is proposed and examples showing the use of this method for simulation of refrigeration systems are given....

  1. HVDC System Characteristics and Simulation Models

    Energy Technology Data Exchange (ETDEWEB)

    Moon, S.I.; Han, B.M.; Jang, G.S. [Electric Enginnering and Science Research Institute, Seoul (Korea)

    2001-07-01

    This report deals with the AC-DC power system simulation method by PSS/E and EUROSTAG for the development of a strategy for the reliable operation of the Cheju-Haenam interconnected system. The simulation using both programs is performed to analyze HVDC simulation models. In addition, the control characteristics of the Cheju-Haenam HVDC system as well as Cheju AC system characteristics are described in this work. (author). 104 figs., 8 tabs.

  2. An explicit relaxation filtering framework based upon Perona-Malik anisotropic diffusion for shock capturing and subgrid scale modeling of Burgers turbulence

    CERN Document Server

    Maulik, Romit

    2016-01-01

    In this paper, we introduce a relaxation filtering closure approach to account for subgrid scale effects in explicitly filtered large eddy simulations using the concept of anisotropic diffusion. We utilize the Perona-Malik diffusion model and demonstrate its shock capturing ability and spectral performance for solving the Burgers turbulence problem, which is a simplified prototype for more realistic turbulent flows showing the same quadratic nonlinearity. Our numerical assessments present the behavior of various diffusivity functions in conjunction with a detailed sensitivity analysis with respect to the free modeling parameters. In comparison to direct numerical simulation (DNS) and under-resolved DNS results, we find that the proposed closure model is efficient in the prevention of energy accumulation at grid cut-off and is also adept at preventing any possible spurious numerical oscillations due to shock formation under the optimal parameter choices. In contrast to other relaxation filtering approaches, it...

  3. Integrated Data Capturing Requirements for 3d Semantic Modelling of Cultural Heritage: the Inception Protocol

    Science.gov (United States)

    Di Giulio, R.; Maietti, F.; Piaia, E.; Medici, M.; Ferrari, F.; Turillazzi, B.

    2017-02-01

    The generation of high quality 3D models can be still very time-consuming and expensive, and the outcome of digital reconstructions is frequently provided in formats that are not interoperable, and therefore cannot be easily accessed. This challenge is even more crucial for complex architectures and large heritage sites, which involve a large amount of data to be acquired, managed and enriched by metadata. In this framework, the ongoing EU funded project INCEPTION - Inclusive Cultural Heritage in Europe through 3D semantic modelling proposes a workflow aimed at the achievements of efficient 3D digitization methods, post-processing tools for an enriched semantic modelling, web-based solutions and applications to ensure a wide access to experts and non-experts. In order to face these challenges and to start solving the issue of the large amount of captured data and time-consuming processes in the production of 3D digital models, an Optimized Data Acquisition Protocol (DAP) has been set up. The purpose is to guide the processes of digitization of cultural heritage, respecting needs, requirements and specificities of cultural assets.

  4. Simulation modeling and analysis with Arena

    Energy Technology Data Exchange (ETDEWEB)

    Tayfur Altiok; Benjamin Melamed [Rutgers University, NJ (United States). Department of Industrial and Systems Engineering

    2007-06-15

    The textbook which treats the essentials of the Monte Carlo discrete-event simulation methodology, and does so in the context of a popular Arena simulation environment. It treats simulation modeling as an in-vitro laboratory that facilitates the understanding of complex systems and experimentation with what-if scenarios in order to estimate their performance metrics. The book contains chapters on the simulation modeling methodology and the underpinnings of discrete-event systems, as well as the relevant underlying probability, statistics, stochastic processes, input analysis, model validation and output analysis. All simulation-related concepts are illustrated in numerous Arena examples, encompassing production lines, manufacturing and inventory systems, transportation systems, and computer information systems in networked settings. Chapter 13.3.3 is on coal loading operations on barges/tugboats.

  5. Application of Computer Simulation Modeling to Medication Administration Process Redesign

    Directory of Open Access Journals (Sweden)

    Nathan Huynh

    2012-01-01

    Full Text Available The medication administration process (MAP is one of the most high-risk processes in health care. MAP workflow redesign can precipitate both unanticipated and unintended consequences that can lead to new medication safety risks and workflow inefficiencies. Thus, it is necessary to have a tool to evaluate the impact of redesign approaches in advance of their clinical implementation. This paper discusses the development of an agent-based MAP computer simulation model that can be used to assess the impact of MAP workflow redesign on MAP performance. The agent-based approach is adopted in order to capture Registered Nurse medication administration performance. The process of designing, developing, validating, and testing such a model is explained. Work is underway to collect MAP data in a hospital setting to provide more complex MAP observations to extend development of the model to better represent the complexity of MAP.

  6. Object Oriented Modelling and Dynamical Simulation

    DEFF Research Database (Denmark)

    Wagner, Falko Jens; Poulsen, Mikael Zebbelin

    1998-01-01

    This report with appendix describes the work done in master project at DTU.The goal of the project was to develop a concept for simulation of dynamical systems based on object oriented methods.The result was a library of C++-classes, for use when both building componentbased models and when...... onduction simulation experiments....

  7. Modeling and simulation for RF system design

    CERN Document Server

    Frevert, Ronny; Jancke, Roland; Knöchel, Uwe; Schwarz, Peter; Kakerow, Ralf; Darianian, Mohsen

    2005-01-01

    Focusing on RF specific modeling and simulation methods, and system and circuit level descriptions, this work contains application-oriented training material. Accompanied by a CD- ROM, it combines the presentation of a mixed-signal design flow, an introduction into VHDL-AMS and Verilog-A, and the application of commercially available simulators.

  8. Automatic human body modeling for vision-based motion capture system using B-spline parameterization of the silhouette

    Science.gov (United States)

    Jaume-i-Capó, Antoni; Varona, Javier; González-Hidalgo, Manuel; Mas, Ramon; Perales, Francisco J.

    2012-02-01

    Human motion capture has a wide variety of applications, and in vision-based motion capture systems a major issue is the human body model and its initialization. We present a computer vision algorithm for building a human body model skeleton in an automatic way. The algorithm is based on the analysis of the human shape. We decompose the body into its main parts by computing the curvature of a B-spline parameterization of the human contour. This algorithm has been applied in a context where the user is standing in front of a camera stereo pair. The process is completed after the user assumes a predefined initial posture so as to identify the main joints and construct the human model. Using this model, the initialization problem of a vision-based markerless motion capture system of the human body is solved.

  9. Hierarchical spatial capture-recapture models: Modeling population density from stratified populations

    Science.gov (United States)

    Royle, J. Andrew; Converse, Sarah J.

    2014-01-01

    Capture–recapture studies are often conducted on populations that are stratified by space, time or other factors. In this paper, we develop a Bayesian spatial capture–recapture (SCR) modelling framework for stratified populations – when sampling occurs within multiple distinct spatial and temporal strata.We describe a hierarchical model that integrates distinct models for both the spatial encounter history data from capture–recapture sampling, and also for modelling variation in density among strata. We use an implementation of data augmentation to parameterize the model in terms of a latent categorical stratum or group membership variable, which provides a convenient implementation in popular BUGS software packages.We provide an example application to an experimental study involving small-mammal sampling on multiple trapping grids over multiple years, where the main interest is in modelling a treatment effect on population density among the trapping grids.Many capture–recapture studies involve some aspect of spatial or temporal replication that requires some attention to modelling variation among groups or strata. We propose a hierarchical model that allows explicit modelling of group or strata effects. Because the model is formulated for individual encounter histories and is easily implemented in the BUGS language and other free software, it also provides a general framework for modelling individual effects, such as are present in SCR models.

  10. Modeling and simulation of complex systems a framework for efficient agent-based modeling and simulation

    CERN Document Server

    Siegfried, Robert

    2014-01-01

    Robert Siegfried presents a framework for efficient agent-based modeling and simulation of complex systems. He compares different approaches for describing structure and dynamics of agent-based models in detail. Based on this evaluation the author introduces the "General Reference Model for Agent-based Modeling and Simulation" (GRAMS). Furthermore he presents parallel and distributed simulation approaches for execution of agent-based models -from small scale to very large scale. The author shows how agent-based models may be executed by different simulation engines that utilize underlying hard

  11. Modeling of CO2 Solubility in Aqueous Potassium Lysinate Solutions at Post-Combustion CO2 Capture Conditions

    Science.gov (United States)

    Bian, Y.; Shen, S.

    2017-05-01

    Aqueous potassium lysinate (LysK) has been proposed as an alternative to aqueous alkanolamines for CO2 capture due to fast kinetics and large absorption capacity. However, thermodynamic modeling for aqueous LysK system has not been available yet. In this work, a modified Kent-Eisenberg model with correlated equilibrium constants was developed to interpret the vapor-liquid equilibrium (VLE) data at postcombustion capture conditions. The predictions from the developed model are in good agreement with the experimental results with AAD within 19 %.

  12. Assessment of large-eddy simulation in capturing preferential concentration of heavy particles in isotropic turbulent flows

    Science.gov (United States)

    Jin, Guodong; Zhang, Jian; He, Guo-Wei; Wang, Lian-Ping

    2010-12-01

    Particle-laden turbulent flow is a typical non-equilibrium process characterized by particle relaxation time τp and the characteristic timescale of the flows τf, in which the turbulent mixing of heavy particles is related to different scales of fluid motions. The preferential concentration (PC) of heavy particles could be strongly affected by fluid motion at dissipation-range scales, which presents a major challenge to the large-eddy simulation (LES) approach. The errors in simulated PC by LES are due to both filtering and the subgrid scale (SGS) eddy viscosity model. The former leads to the removal of the SGS motion and the latter usually results in a more spatiotemporally correlated vorticity field. The dependence of these two factors on the flow Reynolds number is assessed using a priori and a posteriori tests, respectively. The results suggest that filtering is the dominant factor for the under-prediction of the PC for Stokes numbers less than 1, while the SGS eddy viscosity model is the dominant factor for the over-prediction of the PC for Stokes numbers between 1 and 10. The effects of the SGS eddy viscosity model on the PC decrease as the Reynolds number and Stokes number increase. LES can well predict the PC for particle Stokes numbers larger than 10. An SGS model for particles with small and intermediate Stokes numbers is needed to account for the effects of the removed SGS turbulent motion on the PC.

  13. Assessment of large-eddy simulation in capturing preferential concentration of heavy particles in isotropic turbulent flows

    Energy Technology Data Exchange (ETDEWEB)

    Jin Guodong; Zhang Jian; He Guowei; Wang Lianping, E-mail: hgw@lnm.imech.ac.cn [LNM, Institute of Mechanics, Chinese Academy of Sciences, Beijing 100190 (China)

    2010-12-15

    Particle-laden turbulent flow is a typical non-equilibrium process characterized by particle relaxation time {tau}{sub p} and the characteristic timescale of the flows {tau}{sub f}, in which the turbulent mixing of heavy particles is related to different scales of fluid motions. The preferential concentration (PC) of heavy particles could be strongly affected by fluid motion at dissipation-range scales, which presents a major challenge to the large-eddy simulation (LES) approach. The errors in simulated PC by LES are due to both filtering and the subgrid scale (SGS) eddy viscosity model. The former leads to the removal of the SGS motion and the latter usually results in a more spatiotemporally correlated vorticity field. The dependence of these two factors on the flow Reynolds number is assessed using a priori and a posteriori tests, respectively. The results suggest that filtering is the dominant factor for the under-prediction of the PC for Stokes numbers less than 1, while the SGS eddy viscosity model is the dominant factor for the over-prediction of the PC for Stokes numbers between 1 and 10. The effects of the SGS eddy viscosity model on the PC decrease as the Reynolds number and Stokes number increase. LES can well predict the PC for particle Stokes numbers larger than 10. An SGS model for particles with small and intermediate Stokes numbers is needed to account for the effects of the removed SGS turbulent motion on the PC.

  14. Application of the GEM Inventory Data Capture Tools for Dynamic Vulnerability Assessment and Recovery Modelling

    Science.gov (United States)

    Verrucci, Enrica; Bevington, John; Vicini, Alessandro

    2014-05-01

    A set of open-source tools to create building exposure datasets for seismic risk assessment was developed from 2010-13 by the Inventory Data Capture Tools (IDCT) Risk Global Component of the Global Earthquake Model (GEM). The tools were designed to integrate data derived from remotely-sensed imagery, statistically-sampled in-situ field data of buildings to generate per-building and regional exposure data. A number of software tools were created to aid the development of these data, including mobile data capture tools for in-field structural assessment, and the Spatial Inventory Data Developer (SIDD) for creating "mapping schemes" - statistically-inferred distributions of building stock applied to areas of homogeneous urban land use. These tools were made publically available in January 2014. Exemplar implementations in Europe and Central Asia during the IDCT project highlighted several potential application areas beyond the original scope of the project. These are investigated here. We describe and demonstrate how the GEM-IDCT suite can be used extensively within the framework proposed by the EC-FP7 project SENSUM (Framework to integrate Space-based and in-situ sENSing for dynamic vUlnerability and recovery Monitoring). Specifically, applications in the areas of 1) dynamic vulnerability assessment (pre-event), and 2) recovery monitoring and evaluation (post-event) are discussed. Strategies for using the IDC Tools for these purposes are discussed. The results demonstrate the benefits of using advanced technology tools for data capture, especially in a systematic fashion using the taxonomic standards set by GEM. Originally designed for seismic risk assessment, it is clear the IDCT tools have relevance for multi-hazard risk assessment. When combined with a suitable sampling framework and applied to multi-temporal recovery monitoring, data generated from the tools can reveal spatio-temporal patterns in the quality of recovery activities and resilience trends can be

  15. A sand wave simulation model

    NARCIS (Netherlands)

    Nemeth, A.A.; Hulscher, S.J.M.H.; Damme, van R.M.J.

    2003-01-01

    Sand waves form a prominent regular pattern in the offshore seabeds of sandy shallow seas. A two dimensional vertical (2DV) flow and morphological numerical model describing the behaviour of these sand waves has been developed. The model contains the 2DV shallow water equations, with a free water su

  16. Atomistic simulations of electrolyte solutions and hydrogels with explicit solvent models

    CERN Document Server

    Walter, Jonathan; Reiser, Steffen; Horsch, Martin; Vrabec, Jadran; Hasse, Hans

    2011-01-01

    Two of the most challenging tasks in molecular simulation consist in capturing the properties of systems with long-range interactions (e.g. electrolyte solutions) as well as systems containing large molecules such as hydrogels. For the development and optimization of molecular force fields and models, a large number of simulation runs have to be evaluated to obtain the sensitivity of the target properties with respect to the model parameters. The present work discusses force field development for electrolytes regarding thermodynamic properties of their aqueous solutions. Furthermore, simulations are conducted for the volume transition of hydrogels in the presence of electrolytes. It is shown that the properties of these complex systems can be captured by molecular simulation.

  17. Modelling Reactive and Proactive Behaviour in Simulation

    CERN Document Server

    Majid, Mazlina Abdul; Aickelin, Uwe

    2010-01-01

    This research investigated the simulation model behaviour of a traditional and combined discrete event as well as agent based simulation models when modelling human reactive and proactive behaviour in human centric complex systems. A departmental store was chosen as human centric complex case study where the operation system of a fitting room in WomensWear department was investigated. We have looked at ways to determine the efficiency of new management policies for the fitting room operation through simulating the reactive and proactive behaviour of staff towards customers. Once development of the simulation models and their verification had been done, we carried out a validation experiment in the form of a sensitivity analysis. Subsequently, we executed a statistical analysis where the mixed reactive and proactive behaviour experimental results were compared with some reactive experimental results from previously published works. Generally, this case study discovered that simple proactive individual behaviou...

  18. Challenges in SysML Model Simulation

    Directory of Open Access Journals (Sweden)

    Mara Nikolaidou

    2016-07-01

    Full Text Available Systems Modeling Language (SysML is a standard proposed by the OMG for systems-of-systems (SoS modeling and engineering. To this end, it provides the means to depict SoS components and their behavior in a hierarchical, multi-layer fashion, facilitating alternative engineering activities, such as system design. To explore the performance of SysML, simulation is one of the preferred methods. There are many efforts targeting simulation code generation from SysML models. Numerous simulation methodologies and tools are employed, while different SysML diagrams are utilized. Nevertheless, this process is not standardized, although most of current approaches tend to follow the same steps, even if they employ different tools. The scope of this paper is to provide a comprehensive understanding of the similarities and differences of existing approaches and identify current challenges in fully automating SysML models simulation process.

  19. SIMULATION MODELING SLOW SPATIALLY HETER- OGENEOUS COAGULATION

    Directory of Open Access Journals (Sweden)

    P. A. Zdorovtsev

    2013-01-01

    Full Text Available A new model of spatially inhomogeneous coagulation, i.e. formation of larger clusters by joint interaction of smaller ones, is under study. The results of simulation are compared with known analytical and numerical solutions.

  20. Theory, modeling, and simulation annual report, 1992

    Energy Technology Data Exchange (ETDEWEB)

    1993-05-01

    This report briefly discusses research on the following topics: development of electronic structure methods; modeling molecular processes in clusters; modeling molecular processes in solution; modeling molecular processes in separations chemistry; modeling interfacial molecular processes; modeling molecular processes in the atmosphere; methods for periodic calculations on solids; chemistry and physics of minerals; graphical user interfaces for computational chemistry codes; visualization and analysis of molecular simulations; integrated computational chemistry environment; and benchmark computations.

  1. Application of Chebyshev Polynomial to simulated modeling

    Institute of Scientific and Technical Information of China (English)

    CHI Hai-hong; LI Dian-pu

    2006-01-01

    Chebyshev polynomial is widely used in many fields, and used usually as function approximation in numerical calculation. In this paper, Chebyshev polynomial expression of the propeller properties across four quadrants is given at first, then the expression of Chebyshev polynomial is transformed to ordinary polynomial for the need of simulation of propeller dynamics. On the basis of it,the dynamical models of propeller across four quadrants are given. The simulation results show the efficiency of mathematical model.

  2. Collisionless Electrostatic Shock Modeling and Simulation

    Science.gov (United States)

    2016-10-21

    Briefing Charts 3. DATES COVERED (From - To) 30 September 2016 – 21 October 2016 4. TITLE AND SUBTITLE Collisionless Electrostatic Shock Modeling and...release: distribution unlimited. PA#16490 Air Force Research Laboratory Collisionless Electrostatic Shock Modeling and Simulation Daniel W. Crews In-Space...unlimited. PA#16490 Overview • Motivation and Background • What is a Collisionless Shock Wave? • Features of the Collisionless Shock • The Shock Simulation

  3. Hamiltonian Mapping Revisited: Calibrating Minimalist Models to Capture Molecular Recognition by Intrinsically Disordered Proteins.

    Science.gov (United States)

    Law, Sean M; Ahlstrom, Logan S; Panahi, Afra; Brooks, Charles L

    2014-10-02

    Molecular recognition by intrinsically disordered proteins (IDPs) plays a central role in many critical cellular processes. Toward achieving detailed mechanistic understanding of IDP-target interactions, here we employ the "Hamiltonian mapping" methodology, which is rooted in the weighted histogram analysis method (WHAM), for the fast and efficient calibration of structure-based models in studies of IDPs. By performing reference simulations on a given Hamiltonian, we illustrate for two model IDPs how this method can extrapolate thermodynamic behavior under a range of modified Hamiltonians, in this case representing changes in the binding affinity (Kd) of the system. Given sufficient conformational sampling in a single trajectory, Hamiltonian mapping accurately reproduces Kd values from direct simulation. This method may be generally applied to systems beyond IDPs in force field optimization and in describing changes in thermodynamic behavior as a function of external conditions for connection with experiment.

  4. A dynamic process model of a natural gas combined cycle -- Model development with startup and shutdown simulations

    Energy Technology Data Exchange (ETDEWEB)

    Liese, Eric [U.S. DOE; Zitney, Stephen E. [U.S. DOE

    2013-01-01

    Research in dynamic process simulation for integrated gasification combined cycles (IGCC) with carbon capture has been ongoing at the National Energy Technology Laboratory (NETL), culminating in a full operator training simulator (OTS) and immersive training simulator (ITS) for use in both operator training and research. A derivative work of the IGCC dynamic simulator has been a modification of the combined cycle section to more closely represent a typical natural gas fired combined cycle (NGCC). This paper describes the NGCC dynamic process model and highlights some of the simulator’s current capabilities through a particular startup and shutdown scenario.

  5. Additive Manufacturing Modeling and Simulation A Literature Review for Electron Beam Free Form Fabrication

    Science.gov (United States)

    Seufzer, William J.

    2014-01-01

    Additive manufacturing is coming into industrial use and has several desirable attributes. Control of the deposition remains a complex challenge, and so this literature review was initiated to capture current modeling efforts in the field of additive manufacturing. This paper summarizes about 10 years of modeling and simulation related to both welding and additive manufacturing. The goals were to learn who is doing what in modeling and simulation, to summarize various approaches taken to create models, and to identify research gaps. Later sections in the report summarize implications for closed-loop-control of the process, implications for local research efforts, and implications for local modeling efforts.

  6. Modeling of magnetic particle suspensions for simulations

    CERN Document Server

    Satoh, Akira

    2017-01-01

    The main objective of the book is to highlight the modeling of magnetic particles with different shapes and magnetic properties, to provide graduate students and young researchers information on the theoretical aspects and actual techniques for the treatment of magnetic particles in particle-based simulations. In simulation, we focus on the Monte Carlo, molecular dynamics, Brownian dynamics, lattice Boltzmann and stochastic rotation dynamics (multi-particle collision dynamics) methods. The latter two simulation methods can simulate both the particle motion and the ambient flow field simultaneously. In general, specialized knowledge can only be obtained in an effective manner under the supervision of an expert. The present book is written to play such a role for readers who wish to develop the skill of modeling magnetic particles and develop a computer simulation program using their own ability. This book is therefore a self-learning book for graduate students and young researchers. Armed with this knowledge,...

  7. Ground and excited states Gamow-Teller strength distributions of iron isotopes and associated capture rates for core-collapse simulations

    Science.gov (United States)

    Nabi, Jameel-Un

    2011-02-01

    This paper reports on the microscopic calculation of ground and excited states Gamow-Teller (GT) strength distributions, both in the electron capture and electron decay direction, for 54,55,56Fe. The associated electron and positron capture rates for these isotopes of iron are also calculated in stellar matter. These calculations were recently introduced and this paper is a follow-up which discusses in detail the GT strength distributions and stellar capture rates of key iron isotopes. The calculations are performed within the framework of the proton-neutron quasiparticle random phase approximation (pn-QRPA) theory. The pn-QRPA theory allows a microscopic state-by-state calculation of GT strength functions and stellar capture rates which greatly increases the reliability of the results. For the first time experimental deformation of nuclei are taken into account. In the core of massive stars isotopes of iron, 54,55,56Fe, are considered to be key players in decreasing the electron-to-baryon ratio ( Y e ) mainly via electron capture on these nuclide. The structure of the presupernova star is altered both by the changes in Y e and the entropy of the core material. Results are encouraging and are compared against measurements (where possible) and other calculations. The calculated electron capture rates are in overall good agreement with the shell model results. During the presupernova evolution of massive stars, from oxygen shell burning stages till around end of convective core silicon burning, the calculated electron capture rates on 54Fe are around three times bigger than the corresponding shell model rates. The calculated positron capture rates, however, are suppressed by two to five orders of magnitude.

  8. A data parsimonious model for capturing snapshots of groundwater pollution sources.

    Science.gov (United States)

    Chaubey, Jyoti; Kashyap, Deepak

    2017-02-01

    Presented herein is a data parsimonious model for identification of regional and local groundwater pollution sources at a reference time employing corresponding fields of head, concentration and its time derivative. The regional source flux, assumed to be uniformly distributed, is viewed as the causative factor for the widely prevalent background concentration. The localized concentration-excesses are attributed to flux from local sources distributed around the respective centroids. The groundwater pollution is parameterized by flux from regional and local sources, and distribution parameters of the latter. These parameters are estimated by minimizing the sum of squares of differences between the observed and simulated concentration fields. The concentration field is simulated by a numerical solution of the transient solute transport equation. The equation is solved assuming the temporal derivative term to be known a priori and merging it with the sink term. This strategy circumvents the requirement of dynamic concentration data. The head field is generated using discrete point head data employing a specially devised interpolator that controls the numerical-differentiation errors and simultaneously ensures micro-level mass balance. This measure eliminates the requirement of flow modeling without compromising the sanctity of head field. The model after due verification has been illustrated employing available and simulated data from an area lying between two rivers Yamuna and Krishni in India. Copyright © 2016 Elsevier B.V. All rights reserved.

  9. A data parsimonious model for capturing snapshots of groundwater pollution sources

    Science.gov (United States)

    Chaubey, Jyoti; Kashyap, Deepak

    2017-02-01

    Presented herein is a data parsimonious model for identification of regional and local groundwater pollution sources at a reference time employing corresponding fields of head, concentration and its time derivative. The regional source flux, assumed to be uniformly distributed, is viewed as the causative factor for the widely prevalent background concentration. The localized concentration-excesses are attributed to flux from local sources distributed around the respective centroids. The groundwater pollution is parameterized by flux from regional and local sources, and distribution parameters of the latter. These parameters are estimated by minimizing the sum of squares of differences between the observed and simulated concentration fields. The concentration field is simulated by a numerical solution of the transient solute transport equation. The equation is solved assuming the temporal derivative term to be known a priori and merging it with the sink term. This strategy circumvents the requirement of dynamic concentration data. The head field is generated using discrete point head data employing a specially devised interpolator that controls the numerical-differentiation errors and simultaneously ensures micro-level mass balance. This measure eliminates the requirement of flow modeling without compromising the sanctity of head field. The model after due verification has been illustrated employing available and simulated data from an area lying between two rivers Yamuna and Krishni in India.

  10. Modelling and Simulation of Wave Loads

    DEFF Research Database (Denmark)

    Sørensen, John Dalsgaard; Thoft-Christensen, Palle

    A simple model of the wave load on slender members of offshore structures is described. The wave elevation of the sea state is modelled by a stationary Gaussian process. A new procedure to simulate realizations of the wave loads is developed. The simulation method assumes that the wave particle...... velocity can be approximated by a Gaussian Markov process. Known approximate results for the first-passage density or equivalently, the distribution of the extremes of wave loads are presented and compared with rather precise simulation results. It is demonstrated that the approximate results...

  11. Modelling and Simulation of Wave Loads

    DEFF Research Database (Denmark)

    Sørensen, John Dalsgaard; Thoft-Christensen, Palle

    1985-01-01

    A simple model of the wave load on stender members of offshore structures is described . The wave elevation of the sea stateis modelled by a stationary Gaussian process. A new procedure to simulate realizations of the wave loads is developed. The simulation method assumes that the wave particle...... velocity can be approximated by a Gaussian Markov process. Known approximate results for the first passage density or equivalently, the distribution of the extremes of wave loads are presented and compared with rather precise simulation results. It is demonstrated that the approximate results...

  12. Modeling and simulation of multiport RF switch

    Energy Technology Data Exchange (ETDEWEB)

    Vijay, J [Student, Department of Instrumentation and Control Engineering, National Institute of Technology, Tiruchirappalli-620015 (India); Saha, Ivan [Scientist, Indian Space Research Organisation (ISRO) (India); Uma, G [Lecturer, Department of Instrumentation and Control Engineering, National Institute of Technology, Tiruchirappalli-620015 (India); Umapathy, M [Assistant Professor, Department of Instrumentation and Control Engineering, National Institute of Technology, Tiruchirappalli-620015 (India)

    2006-04-01

    This paper describes the modeling and simulation of 'Multi Port RF Switch' where the latching mechanism is realized with two hot arm electro thermal actuators and the switching action is realized with electrostatic actuators. It can act as single pole single thrown as well as single pole multi thrown switch. The proposed structure is modeled analytically and required parameters are simulated using MATLAB. The analytical simulation results are validated using Finite Element Analysis of the same in the COVENTORWARE software.

  13. Modeling and simulation of discrete event systems

    CERN Document Server

    Choi, Byoung Kyu

    2013-01-01

    Computer modeling and simulation (M&S) allows engineers to study and analyze complex systems. Discrete-event system (DES)-M&S is used in modern management, industrial engineering, computer science, and the military. As computer speeds and memory capacity increase, so DES-M&S tools become more powerful and more widely used in solving real-life problems. Based on over 20 years of evolution within a classroom environment, as well as on decades-long experience in developing simulation-based solutions for high-tech industries, Modeling and Simulation of Discrete-Event Systems is the only book on

  14. Traffic Modeling in WCDMA System Level Simulations

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    Traffic modeling is a crucial element in WCDMA system level simulations. A clear understanding of the nature of traffic in the WCDMA system and subsequent selection of an appropriate random traffic model are critical to the success of the modeling enterprise. The resultant performances will evidently be of a function that our design has been well adapted to the traffic, channel and user mobility models, and these models are also accurate. In this article, our attention will be focused on modeling voice and WWW data traffic with the SBBP model and Victor model respectively.

  15. A transport model for computer simulation of wildfires

    Energy Technology Data Exchange (ETDEWEB)

    Linn, R. [Los Alamos National Lab., NM (United States)

    1997-12-31

    Realistic self-determining simulation of wildfires is a difficult task because of a large variety of important length scales (including scales on the size of twigs or grass and the size of large trees), imperfect data, complex fluid mechanics and heat transfer, and very complicated chemical reactions. The author uses a transport approach to produce a model that exhibits a self-determining propagation rate. The transport approach allows him to represent a large number of environments such as those with nonhomogeneous vegetation and terrain. He accounts for the microscopic details of a fire with macroscopic resolution by dividing quantities into mean and fluctuating parts similar to what is done in traditional turbulence modeling. These divided quantities include fuel, wind, gas concentrations, and temperature. Reaction rates are limited by the mixing process and not the chemical kinetics. The author has developed a model that includes the transport of multiple gas species, such as oxygen and volatile hydrocarbons, and tracks the depletion of various fuels and other stationary solids and liquids. From this model he develops a simplified local burning model with which he performs a number of simulations that demonstrate that he is able to capture the important physics with the transport approach. With this simplified model he is able to pick up the essence of wildfire propagation, including such features as acceleration when transitioning to upsloping terrain, deceleration of fire fronts when they reach downslopes, and crowning in the presence of high winds.

  16. Integrating resource selection into spatial capture-recapture models for large carnivores

    Science.gov (United States)

    Proffitt, Kelly M.; Goldberg, Joshua; Hebblewite, Mark; Russell, Robin E.; Jimenez, Ben; Robinson, Hugh S.; Pilgrim, Kristine; Schwartz, Michael K.

    2015-01-01

    Wildlife managers need reliable methods to estimate large carnivore densities and population trends; yet large carnivores are elusive, difficult to detect, and occur at low densities making traditional approaches intractable. Recent advances in spatial capture-recapture (SCR) models have provided new approaches for monitoring trends in wildlife abundance and these methods are particularly applicable to large carnivores. We applied SCR models in a Bayesian framework to estimate mountain lion densities in the Bitterroot Mountains of west central Montana. We incorporate an existing resource selection function (RSF) as a density covariate to account for heterogeneity in habitat use across the study area and include data collected from harvested lions. We identify individuals through DNA samples collected by (1) biopsy darting mountain lions detected in systematic surveys of the study area, (2) opportunistically collecting hair and scat samples, and (3) sampling all harvested mountain lions. We included 80 DNA samples collected from 62 individuals in the analysis. Including information on predicted habitat use as a covariate on the distribution of activity centers reduced the median estimated density by 44%, the standard deviation by 7%, and the width of 95% credible intervals by 10% as compared to standard SCR models. Within the two management units of interest, we estimated a median mountain lion density of 4.5 mountain lions/100 km2 (95% CI = 2.9, 7.7) and 5.2 mountain lions/100 km2 (95% CI = 3.4, 9.1). Including harvested individuals (dead recovery) did not create a significant bias in the detection process by introducing individuals that could not be detected after removal. However, the dead recovery component of the model did have a substantial effect on results by increasing sample size. The ability to account for heterogeneity in habitat use provides a useful extension to SCR models, and will enhance the ability of wildlife managers to reliably and

  17. Elastic network models capture the motions apparent within ensembles of RNA structures.

    Science.gov (United States)

    Zimmermann, Michael T; Jernigan, Robert L

    2014-06-01

    The role of structure and dynamics in mechanisms for RNA becomes increasingly important. Computational approaches using simple dynamics models have been successful at predicting the motions of proteins and are often applied to ribonucleo-protein complexes but have not been thoroughly tested for well-packed nucleic acid structures. In order to characterize a true set of motions, we investigate the apparent motions from 16 ensembles of experimentally determined RNA structures. These indicate a relatively limited set of motions that are captured by a small set of principal components (PCs). These limited motions closely resemble the motions computed from low frequency normal modes from elastic network models (ENMs), either at atomic or coarse-grained resolution. Various ENM model types, parameters, and structure representations are tested here against the experimental RNA structural ensembles, exposing differences between models for proteins and for folded RNAs. Differences in performance are seen, depending on the structure alignment algorithm used to generate PCs, modulating the apparent utility of ENMs but not significantly impacting their ability to generate functional motions. The loss of dynamical information upon coarse-graining is somewhat larger for RNAs than for globular proteins, indicating, perhaps, the lower cooperativity of the less densely packed RNA. However, the RNA structures show less sensitivity to the elastic network model parameters than do proteins. These findings further demonstrate the utility of ENMs and the appropriateness of their application to well-packed RNA-only structures, justifying their use for studying the dynamics of ribonucleo-proteins, such as the ribosome and regulatory RNAs.

  18. Modelling artificial sea salt emission in large eddy simulations.

    Science.gov (United States)

    Maalick, Z; Korhonen, H; Kokkola, H; Kühn, T; Romakkaniemi, S

    2014-12-28

    We study the dispersion of sea salt particles from artificially injected sea spray at a cloud-resolving scale. Understanding of how different aerosol processes affect particle dispersion is crucial when designing emission sources for marine cloud brightening. Compared with previous studies, we include for the first time an explicit treatment of aerosol water, which takes into account condensation, evaporation and their effect on ambient temperature. This enables us to capture the negative buoyancy caused by water evaporation from aerosols. Additionally, we use a higher model resolution to capture aerosol loss through coagulation near the source point. We find that, with a seawater flux of 15 kg s(-1), the cooling due to evaporation can be as much as 1.4 K, causing a delay in particle dispersion of 10-20 min. This delay enhances particle scavenging by a factor of 1.14 compared with simulations without aerosol water. We further show that both cooling and particle dispersion depend on the model resolution, with a maximum particle scavenging efficiency of 20% within 5 h after emission at maximum resolution of 50 m. Based on these results, we suggest further regional high-resolution studies which model several injection periods over several weeks.

  19. Modelling artificial sea salt emission in large eddy simulations

    Science.gov (United States)

    Maalick, Z.; Korhonen, H.; Kokkola, H.; Kühn, T.; Romakkaniemi, S.

    2014-01-01

    We study the dispersion of sea salt particles from artificially injected sea spray at a cloud-resolving scale. Understanding of how different aerosol processes affect particle dispersion is crucial when designing emission sources for marine cloud brightening. Compared with previous studies, we include for the first time an explicit treatment of aerosol water, which takes into account condensation, evaporation and their effect on ambient temperature. This enables us to capture the negative buoyancy caused by water evaporation from aerosols. Additionally, we use a higher model resolution to capture aerosol loss through coagulation near the source point. We find that, with a seawater flux of 15 kg s−1, the cooling due to evaporation can be as much as 1.4 K, causing a delay in particle dispersion of 10–20 min. This delay enhances particle scavenging by a factor of 1.14 compared with simulations without aerosol water. We further show that both cooling and particle dispersion depend on the model resolution, with a maximum particle scavenging efficiency of 20% within 5 h after emission at maximum resolution of 50 m. Based on these results, we suggest further regional high-resolution studies which model several injection periods over several weeks. PMID:25404679

  20. Lower extremity finite element model for crash simulation

    Energy Technology Data Exchange (ETDEWEB)

    Schauer, D.A.; Perfect, S.A.

    1996-03-01

    A lower extremity model has been developed to study occupant injury mechanisms of the major bones and ligamentous soft tissues resulting from vehicle collisions. The model is based on anatomically correct digitized bone surfaces of the pelvis, femur, patella and the tibia. Many muscles, tendons and ligaments were incrementally added to the basic bone model. We have simulated two types of occupant loading that occur in a crash environment using a non-linear large deformation finite element code. The modeling approach assumed that the leg was passive during its response to the excitation, that is, no active muscular contraction and therefore no active change in limb stiffness. The approach recognized that the most important contributions of the muscles to the lower extremity response are their ability to define and modify the impedance of the limb. When nonlinear material behavior in a component of the leg model was deemed important to response, a nonlinear constitutive model was incorporated. The accuracy of these assumptions can be verified only through a review of analysis results and careful comparison with test data. As currently defined, the model meets the objective for which it was created. Much work remains to be done, both from modeling and analysis perspectives, before the model can be considered complete. The model implements a modeling philosophy that can accurately capture both kinematic and kinetic response of the lower limb. We have demonstrated that the lower extremity model is a valuable tool for understanding the injury processes and mechanisms. We are now in a position to extend the computer simulation to investigate the clinical fracture patterns observed in actual crashes. Additional experience with this model will enable us to make a statement on what measures are needed to significantly reduce lower extremity injuries in vehicle crashes. 6 refs.

  1. Modeling and simulation of luminescence detection platforms.

    Science.gov (United States)

    Salama, Khaled; Eltoukhy, Helmy; Hassibi, Arjang; El-Gamal, Abbas

    2004-06-15

    Motivated by the design of an integrated CMOS-based detection platform, a simulation model for CCD and CMOS imager-based luminescence detection systems is developed. The model comprises four parts. The first portion models the process of photon flux generation from luminescence probes using ATP-based and luciferase label-based assay kinetics. An optics simulator is then used to compute the incident photon flux on the imaging plane for a given photon flux and system geometry. Subsequently, the output image is computed using a detailed imaging sensor model that accounts for photodetector spectral response, dark current, conversion gain, and various noise sources. Finally, signal processing algorithms are applied to the image to enhance detection reliability and hence increase the overall system throughput. To validate the model, simulation results are compared to experimental results obtained from a CCD-based system that was built to emulate the integrated CMOS-based platform.

  2. SOFT MODELLING AND SIMULATION IN STRATEGY

    Directory of Open Access Journals (Sweden)

    Luciano Rossoni

    2006-06-01

    Full Text Available A certain resistance on the part of the responsible controllers for the strategy exists, in using techniques and tools of modeling and simulation. Many find them excessively complicated, already others see them as rigid and mathematical for excessively for the use of strategies in uncertain and turbulent environments. However, some interpretative boarding that take care of, in part exist, the necessities of these borrowers of decision. The objective of this work is to demonstrate of a clear and simple form, some of the most powerful boarding, methodologies and interpretative tools (soft of modeling and simulation in the business-oriented area of strategy. We will define initially, what they are on models, simulation and some aspects to the modeling and simulation in the strategy area. Later we will see some boarding of modeling soft, that they see the modeling process much more of that simply a mechanical process, therefore, as seen for Simon, the human beings rationally are limited and its decisions are influenced by a series of questions of subjective character, related to the way where it is inserted. Keywords: strategy, modeling and simulation, soft systems methodology, cognitive map, systems dynamics.

  3. Modelling and simulating fire tube boiler performance

    DEFF Research Database (Denmark)

    Sørensen, K.; Condra, T.; Houbak, Niels;

    2003-01-01

    A model for a flue gas boiler covering the flue gas and the water-/steam side has been formulated. The model has been formulated as a number of sub models that are merged into an overall model for the complete boiler. Sub models have been defined for the furnace, the convection zone (split in 2......: a zone submerged in water and a zone covered by steam), a model for the material in the boiler (the steel) and 2 models for resp. the water/steam zone (the boiling) and the steam. The dynamic model has been developed as a number of Differential-Algebraic-Equation system (DAE). Subsequently Mat......Lab/Simulink has been applied for carrying out the simulations. To be able to verify the simulated results experiments has been carried out on a full scale boiler plant....

  4. Modelling and simulating fire tube boiler performance

    DEFF Research Database (Denmark)

    Sørensen, Kim; Karstensen, Claus; Condra, Thomas Joseph;

    2003-01-01

    A model for a ue gas boiler covering the ue gas and the water-/steam side has been formulated. The model has been formulated as a number of sub models that are merged into an overall model for the complete boiler. Sub models have been dened for the furnace, the convection zone (split in 2: a zone...... submerged in water and a zone covered by steam), a model for the material in the boiler (the steel) and 2 models for resp. the water/steam zone (the boiling) and the steam. The dynamic model has been developed as a number of Differential-Algebraic- Equation system (DAE). Subsequently MatLab/Simulink has...... been applied for carrying out the simulations. To be able to verify the simulated results an experiments has been carried out on a full scale boiler plant....

  5. Computer simulations of the random barrier model

    DEFF Research Database (Denmark)

    Schrøder, Thomas; Dyre, Jeppe

    2002-01-01

    A brief review of experimental facts regarding ac electronic and ionic conduction in disordered solids is given followed by a discussion of what is perhaps the simplest realistic model, the random barrier model (symmetric hopping model). Results from large scale computer simulations are presented......, focusing on universality of the ac response in the extreme disorder limit. Finally, some important unsolved problems relating to hopping models for ac conduction are listed....

  6. Characteristic X ray emission in gadolinium following neutron capture as an improved method of in vivo measurement: A comparison between feasibility experiment and Monte-Carlo simulation

    Energy Technology Data Exchange (ETDEWEB)

    Graefe, J.L., E-mail: grafejl@mcmaster.ca [Department of Medical Physics and Applied Radiation Sciences, McMaster University, Hamilton, Ontario, L8S 4K1 (Canada); McNeill, F.E.; Chettle, D.R.; Byun, S.H. [Department of Medical Physics and Applied Radiation Sciences, McMaster University, Hamilton, Ontario, L8S 4K1 (Canada)

    2012-06-15

    We have extended our previous experimental and Monte-Carlo work on the detection of Gd by in vivo prompt gamma neutron activation analysis to include X ray emission. In this paper we incorporate the characteristic K X ray emission that occurs due to internal conversion from the de-excitation of the {sup 155}Gd(n,{gamma}){sup 156}Gd{sup Asterisk-Operator} and {sup 157}Gd(n,{gamma}){sup 158}Gd{sup Asterisk-Operator} reactions. The experimental Gd K X ray intensities are compared with the Monte-Carlo model and demonstrate excellent agreement. The experiment was consistently higher than simulation by 5%. For the detection system used, the Gd K{sub {alpha}} X rays are about 1.5 times as intense as the most dominant prompt gamma ray from the {sup 157}Gd(n,{gamma}) reaction. The partial elemental cross section for K{sub {alpha}} X ray emission is {approx}1.35 times larger than that of the most dominant prompt gamma ray from neutron capture of {sup 157}Gd alone. The use of the K X rays was found to improve the sensitivity of the proposed system to measure Gd retention after exposure to a Gd-based MRI contrast agent. The detection limit in phantoms was {approx}30% better when the X ray signal was incorporated into the analysis method, reducing the detection limit from 0.89 to 0.64 ppm Gd.

  7. Amine-tethered adsorbents based on three-dimensional macroporous silica for CO(2) capture from simulated flue gas and air.

    Science.gov (United States)

    Liu, Fa-Qian; Wang, Lei; Huang, Zhao-Ge; Li, Chao-Qin; Li, Wei; Li, Rong-Xun; Li, Wei-Hua

    2014-03-26

    New covalently tethered CO2 adsorbents are synthesized through the in situ polymerization of N-carboxyanhydride (NCA) of l-alanine from amine-functionalized three-dimensional (3D) interconnected macroporous silica (MPS). The interconnected macropores provide low-resistant pathways for the diffusion of CO2 molecules, while the abundant mesopores ensure the high pore volume. The adsorbents exhibit high molecular weight (of up to 13058 Da), high amine loading (more than 10.98 mmol N g(-1)), fast CO2 capture kinetics (t1/2 CO2 g(-1) in simulated flue gas and 2.65 mmol CO2 g(-1) in simulated ambient air under 1 atm of dry CO2), as well as good stability over 120 adsorption-desorption cycles, which allows the overall CO2 capture process to be promising and sustainable.

  8. Spatial capture-recapture models for jointly estimating population density and landscape connectivity

    Science.gov (United States)

    Royle, J. Andrew; Chandler, Richard B.; Gazenski, Kimberly D.; Graves, Tabitha A.

    2013-01-01

    Population size and landscape connectivity are key determinants of population viability, yet no methods exist for simultaneously estimating density and connectivity parameters. Recently developed spatial capture–recapture (SCR) models provide a framework for estimating density of animal populations but thus far have not been used to study connectivity. Rather, all applications of SCR models have used encounter probability models based on the Euclidean distance between traps and animal activity centers, which implies that home ranges are stationary, symmetric, and unaffected by landscape structure. In this paper we devise encounter probability models based on “ecological distance,” i.e., the least-cost path between traps and activity centers, which is a function of both Euclidean distance and animal movement behavior in resistant landscapes. We integrate least-cost path models into a likelihood-based estimation scheme for spatial capture–recapture models in order to estimate population density and parameters of the least-cost encounter probability model. Therefore, it is possible to make explicit inferences about animal density, distribution, and landscape connectivity as it relates to animal movement from standard capture–recapture data. Furthermore, a simulation study demonstrated that ignoring landscape connectivity can result in negatively biased density estimators under the naive SCR model.

  9. A Node Model Capturing Turning Lane Capacity and Physical Queuing for the Dynamic Network Loading Problem

    Directory of Open Access Journals (Sweden)

    Mingxia Gao

    2012-01-01

    Full Text Available An analytical dynamic node-based model is proposed to represent flows on a traffic network and to be utilized as an integral part of a dynamic network loading (DNL process by solving a continuous DNL problem. The proposed model formulation has an integrate base to be structured with a link load computing component, where physical queuing and its influence were explicitly taken into account by dividing a link into two parts: running part and queuing part. The solution to the model is obtained by a hybridization algorithm of simulation and analytical approach, where an iteration process is conducted to update time-dependent network flow conditions after a reasonable discretization of the problem. The performance of the proposed model, as a DNL model, is tested on a sample network. It is seen that the proposed model provides consistent approximations to link flow dynamics. The dynamic node model proposed in this paper is unique in that it explicitly models directional queue in each turning lane and the First-In-First-Out (FIFO rule at lane level rather than link level is pursued.

  10. Protein–Mineral Interactions: Molecular Dynamics Simulations Capture Importance of Variations in Mineral Surface Composition and Structure

    Energy Technology Data Exchange (ETDEWEB)

    Andersen, Amity; Reardon, Patrick N.; Chacon, Stephany S.; Qafoku, Nikolla P.; Washton, Nancy M.; Kleber, Markus

    2016-06-21

    Molecular dynamics simulations, conventional and metadynamics, were performed to determine the interaction of model protein Gb1 over kaolinite (001), Na+-montmorillonite (001), Ca2+-montmorillonite (001), goethite (100), and Na+-birnessite (001) mineral surfaces. Gb1, a small (56 residue) protein with a well-characterized solution-state nuclear magnetic resonance (NMR) structure and having α-helix, four-fold β-sheet, and hydrophobic core features, is used as a model protein to study protein soil mineral interactions and gain insights on structural changes and potential degradation of protein. From our simulations, we observe little change to the hydrated Gb1 structure over the kaolinite, montmorillonite, and goethite surfaces relative to its solvated structure without these mineral surfaces present. Over the Na+-birnessite basal surface, however, the Gb1 structure is highly disturbed as a result of interaction with this birnessite surface. Unraveling of the Gb1 β-sheet at specific turns and a partial unraveling of the α-helix is observed over birnessite, which suggests specific vulnerable residue sites for oxidation or hydrolysis possibly leading to fragmentation.

  11. An Active Region Model for Capturing Fractal Flow Patterns inUnsaturated Soils: Model Development

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Hui-Hai; Zhang, R.; Bodvarsson, Gudmundur S.

    2005-06-11

    Preferential flow commonly observed in unsaturated soils allows rapid movement of solute from the soil surface or vadose zone to the groundwater, bypassing a significant volume of unsaturated soil and increasing the risk of groundwater contamination. A variety of evidence indicates that complex preferential patterns observed from fields are fractals. In this study, we developed a relatively simple active region model to incorporate the fractal flow pattern into the continuum approach. In the model, the flow domain is divided into active and inactive regions. Flow occurs preferentially in the active region (characterized by fractals), and inactive region is simply bypassed. A new constitutive relationship (the portion of the active region as a function of saturation) was derived. The validity of the proposed model is demonstrated by the consistency between field observations and the new constitutive relationship.

  12. Modeling and simulating of unloading welding transformer

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    The simulation model of an unloading welding transformer was established on the basis of MATLAB software, and the modeling principle was described in detail in the paper. The model was made up of three sub-models, i.e. the linear inductor sub-model, the non-linear inductor sub-model and series connection sub-model controlled by current, and these sub-models were jointed together by means of segmented linearization. The simulating results showed that, in the conditions of the high convert frequency and the large cross section of the magnet core of a welding transformer, the non-linear inductor sub-model can be substituted by a linear inductor sub-model in the model; and the leakage reactance in the welding transformer is one of the main reasons of producing over-current and over-voltage in the inverter. The simulation results demonstrate that the over-voltage produced by leakage reactance is nearly two times of the input voltage supplied to the transformer, and the lasting time of over-voltage depends on time constant τ1. With reducing of τ1, the amplitude of the over-current will increase, and the lasting time becomes shorter. Contrarily, with increasing of τ1, the amplitude of the over-current will decrease, and the lasting time becomes longer. The model has played the important role for the development of the inverter resistance welding machine.

  13. Revolutions in energy through modeling and simulation

    Energy Technology Data Exchange (ETDEWEB)

    Tatro, M.; Woodard, J.

    1998-08-01

    The development and application of energy technologies for all aspects from generation to storage have improved dramatically with the advent of advanced computational tools, particularly modeling and simulation. Modeling and simulation are not new to energy technology development, and have been used extensively ever since the first commercial computers were available. However, recent advances in computing power and access have broadened the extent and use, and, through increased fidelity (i.e., accuracy) of the models due to greatly enhanced computing power, the increased reliance on modeling and simulation has shifted the balance point between modeling and experimentation. The complex nature of energy technologies has motivated researchers to use these tools to understand better performance, reliability and cost issues related to energy. The tools originated in sciences such as the strength of materials (nuclear reactor containment vessels); physics, heat transfer and fluid flow (oil production); chemistry, physics, and electronics (photovoltaics); and geosciences and fluid flow (oil exploration and reservoir storage). Other tools include mathematics, such as statistics, for assessing project risks. This paper describes a few advancements made possible by these tools and explores the benefits and costs of their use, particularly as they relate to the acceleration of energy technology development. The computational complexity ranges from basic spreadsheets to complex numerical simulations using hardware ranging from personal computers (PCs) to Cray computers. In all cases, the benefits of using modeling and simulation relate to lower risks, accelerated technology development, or lower cost projects.

  14. Inventory Reduction Using Business Process Reengineering and Simulation Modeling.

    Science.gov (United States)

    1996-12-01

    center is analyzed using simulation modeling and business process reengineering (BPR) concepts. The two simulation models were designed and evaluated by...reengineering and simulation modeling offer powerful tools to aid the manager in reducing cycle time and inventory levels.

  15. Modeling, Identification, Estimation, and Simulation of Urban Traffic Flow in Jakarta and Bandung

    Directory of Open Access Journals (Sweden)

    Herman Y. Sutarto

    2015-06-01

    Full Text Available This paper presents an overview of urban traffic flow from the perspective of system theory and stochastic control. The topics of modeling, identification, estimation and simulation techniques are evaluated and validated using actual traffic flow data from the city of Jakarta and Bandung, Indonesia, and synthetic data generated from traffic micro-simulator VISSIM. The results on particle filter (PF based state estimation and Expectation-Maximization (EM based parameter estimation (identification confirm the proposed model gives satisfactory results that capture the variation of urban traffic flow. The combination of the technique and the simulator platform assembles possibility to develop a real-time traffic light controller.  

  16. Simulation and modeling of turbulent flows

    CERN Document Server

    Gatski, Thomas B; Lumley, John L

    1996-01-01

    This book provides students and researchers in fluid engineering with an up-to-date overview of turbulent flow research in the areas of simulation and modeling. A key element of the book is the systematic, rational development of turbulence closure models and related aspects of modern turbulent flow theory and prediction. Starting with a review of the spectral dynamics of homogenous and inhomogeneous turbulent flows, succeeding chapters deal with numerical simulation techniques, renormalization group methods and turbulent closure modeling. Each chapter is authored by recognized leaders in their respective fields, and each provides a thorough and cohesive treatment of the subject.

  17. Modeling & Simulation Executive Agent Panel

    Science.gov (United States)

    2007-11-02

    Richard W. ; 5d. PROJECT NUMBER 5e. TASK NUMBER 5f. WORK UNIT NUMBER 7. PERFORMING ORGANIZATION NAME AND ADDRESS Office of the Oceanographer of the Navy...acquisition, and training communities.” MSEA Role • Facilitator in the project startup phase • Catalyst during development • Certifier in the...ACOUSTIC MODELS Parabolic Equation 5.0 ASTRAL 5.0 ASPM 4.3 Gaussian Ray Bundle 1.0 High Freq Env Acoustic (HFEVA) 1.0 COLOSSUS II 1.0 Low Freq Bottom LOSS

  18. MODELLING, SIMULATING AND OPTIMIZING BOILERS

    DEFF Research Database (Denmark)

    Sørensen, K.; Condra, T.; Houbak, Niels

    2003-01-01

    , and the total stress level (i.e. stresses introduced due to internal pressure plus stresses introduced due to temperature gradients) must always be kept below the allowable stress level. In this way, the increased water-/steam space that should allow for better dynamic performance, in the end causes limited...... freedom with respect to dynamic operation of the plant. By means of an objective function including as well the price of the plant as a quantification of the value of dynamic operation of the plant an optimization is carried out. The dynamic model of the boiler plant is applied to define parts...

  19. Modelling, simulating and optimizing Boilers

    DEFF Research Database (Denmark)

    Sørensen, Kim; Condra, Thomas Joseph; Houbak, Niels

    2003-01-01

    , and the total stress level (i.e. stresses introduced due to internal pressure plus stresses introduced due to temperature gradients) must always be kept below the allowable stress level. In this way, the increased water-/steam space that should allow for better dynamic performance, in the end causes limited...... freedom with respect to dynamic operation of the plant. By means of an objective function including as well the price of the plant as a quantication of the value of dynamic operation of the plant an optimization is carried out. The dynamic model of the boiler plant is applied to dene parts...

  20. Simulering af dagslys i digitale modeller

    DEFF Research Database (Denmark)

    Villaume, René Domine; Ørstrup, Finn Rude

    2004-01-01

    Projektet undersøger via forskellige simuleringer af dagslys, kvaliteten af visualiseringer af komplekse lysforhold i digitale modeller i forbindelse med formidling af arkitektur via nettet. I en digital 3D model af Utzon Associates Paustians hus, simulers naturligt dagslysindfald med  forskellig...... Renderingsmetoder som: "shaded render" /  ”raytraceing” /  "Final Gather /  ”Global Illumination”...

  1. Validity of microgravity simulation models on earth

    DEFF Research Database (Denmark)

    Regnard, J; Heer, M; Drummer, C

    2001-01-01

    Many studies have used water immersion and head-down bed rest as experimental models to simulate responses to microgravity. However, some data collected during space missions are at variance or in contrast with observations collected from experimental models. These discrepancies could reflect inc...

  2. Molecular simulation and modeling of complex I.

    Science.gov (United States)

    Hummer, Gerhard; Wikström, Mårten

    2016-07-01

    Molecular modeling and molecular dynamics simulations play an important role in the functional characterization of complex I. With its large size and complicated function, linking quinone reduction to proton pumping across a membrane, complex I poses unique modeling challenges. Nonetheless, simulations have already helped in the identification of possible proton transfer pathways. Simulations have also shed light on the coupling between electron and proton transfer, thus pointing the way in the search for the mechanistic principles underlying the proton pump. In addition to reviewing what has already been achieved in complex I modeling, we aim here to identify pressing issues and to provide guidance for future research to harness the power of modeling in the functional characterization of complex I. This article is part of a Special Issue entitled Respiratory complex I, edited by Volker Zickermann and Ulrich Brandt. Copyright © 2016 Elsevier B.V. All rights reserved.

  3. Hybrid simulation models of production networks

    CERN Document Server

    Kouikoglou, Vassilis S

    2001-01-01

    This book is concerned with a most important area of industrial production, that of analysis and optimization of production lines and networks using discrete-event models and simulation. The book introduces a novel approach that combines analytic models and discrete-event simulation. Unlike conventional piece-by-piece simulation, this method observes a reduced number of events between which the evolution of the system is tracked analytically. Using this hybrid approach, several models are developed for the analysis of production lines and networks. The hybrid approach combines speed and accuracy for exceptional analysis of most practical situations. A number of optimization problems, involving buffer design, workforce planning, and production control, are solved through the use of hybrid models.

  4. Investigating Output Accuracy for a Discrete Event Simulation Model and an Agent Based Simulation Model

    CERN Document Server

    Majid, Mazlina Abdul; Siebers, Peer-Olaf

    2010-01-01

    In this paper, we investigate output accuracy for a Discrete Event Simulation (DES) model and Agent Based Simulation (ABS) model. The purpose of this investigation is to find out which of these simulation techniques is the best one for modelling human reactive behaviour in the retail sector. In order to study the output accuracy in both models, we have carried out a validation experiment in which we compared the results from our simulation models to the performance of a real system. Our experiment was carried out using a large UK department store as a case study. We had to determine an efficient implementation of management policy in the store's fitting room using DES and ABS. Overall, we have found that both simulation models were a good representation of the real system when modelling human reactive behaviour.

  5. A multi-resolution model to capture both global fluctuations of an enzyme and molecular recognition in the ligand-binding site

    CERN Document Server

    Fogarty, Aoife C; Kremer, Kurt

    2016-01-01

    In multi-resolution simulations, different system components are simultaneously modelled at different levels of resolution, these being smoothly coupled together. In the case of enzyme systems, computationally expensive atomistic detail is needed in the active site to capture the chemistry of substrate binding. Global properties of the rest of the protein also play an essential role, determining the structure and fluctuations of the binding site; however, these can be modelled on a coarser level. Similarly, in the most computationally efficient scheme only the solvent hydrating the active site requires atomistic detail. We present a methodology to couple atomistic and coarse-grained protein models, while solvating the atomistic part of the protein in atomistic water. This allows a free choice of which protein and solvent degrees of freedom to include atomistically, without loss of accuracy in the atomistic description. This multi-resolution methodology can successfully model stable ligand binding, and we furt...

  6. Power electronics system modeling and simulation

    Energy Technology Data Exchange (ETDEWEB)

    Lai, Jih-Sheng

    1994-12-31

    This paper introduces control system design based softwares, SIMNON and MATLAB/SIMULINK, for power electronics system simulation. A complete power electronics system typically consists of a rectifier bridge along with its smoothing capacitor, an inverter, and a motor. The system components, featuring discrete or continuous, linear or nonlinear, are modeled in mathematical equations. Inverter control methods,such as pulse-width-modulation and hysteresis current control, are expressed in either computer algorithms or digital circuits. After describing component models and control methods, computer programs are then developed for complete systems simulation. Simulation results are mainly used for studying system performances, such as input and output current harmonics, torque ripples, and speed responses. Key computer programs and simulation results are demonstrated for educational purposes.

  7. Simulation of Gravity Currents Using VOF Model

    Institute of Scientific and Technical Information of China (English)

    邹建锋; 黄钰期; 应新亚; 任安禄

    2002-01-01

    By the Volume of Fluid (VOF) multiphase flow model two-dimensional gravity currents with three phases including air are numerically simulated in this article. The necessity of consideration of turbulence effect for high Reynolds numbers is demonstrated quantitatively by LES (the Large Eddy Simulation) turbulence model. The gravity currents are simulated for h ≠ H as well as h = H, where h is the depth of the gravity current before the release and H is the depth of the intruded fluid. Uprising of swell occurs when a current flows horizontally into another lighter one for h ≠ H. The problems under what condition the uprising of swell occurs and how long it takes are considered in this article. All the simulated results are in reasonable agreement with the experimental results available.

  8. Simulating carbon exchange using a regional atmospheric model coupled to an advanced land-surface model

    Directory of Open Access Journals (Sweden)

    H. W. Ter Maat

    2010-08-01

    Full Text Available This paper is a case study to investigate what the main controlling factors are that determine atmospheric carbon dioxide content for a region in the centre of The Netherlands. We use the Regional Atmospheric Modelling System (RAMS, coupled with a land surface scheme simulating carbon, heat and momentum fluxes (SWAPS-C, and including also submodels for urban and marine fluxes, which in principle should include the dominant mechanisms and should be able to capture the relevant dynamics of the system. To validate the model, observations are used that were taken during an intensive observational campaign in central Netherlands in summer 2002. These include flux-tower observations and aircraft observations of vertical profiles and spatial fluxes of various variables.

    The simulations performed with the coupled regional model (RAMS-SWAPS-C are in good qualitative agreement with the observations. The station validation of the model demonstrates that the incoming shortwave radiation and surface fluxes of water and CO2 are well simulated. The comparison against aircraft data shows that the regional meteorology (i.e. wind, temperature is captured well by the model. Comparing spatially explicitly simulated fluxes with aircraft observed fluxes we conclude that in general latent heat fluxes are underestimated by the model compared to the observations but that the latter exhibit large variability within all flights. Sensitivity experiments demonstrate the relevance of the urban emissions of carbon dioxide for the carbon balance in this particular region. The same tests also show the relation between uncertainties in surface fluxes and those in atmospheric concentrations.

  9. Directed natural product biosynthesis gene cluster capture and expression in the model bacterium Bacillus subtilis

    Science.gov (United States)

    Li, Yongxin; Li, Zhongrui; Yamanaka, Kazuya; Xu, Ying; Zhang, Weipeng; Vlamakis, Hera; Kolter, Roberto; Moore, Bradley S.; Qian, Pei-Yuan

    2015-03-01

    Bacilli are ubiquitous low G+C environmental Gram-positive bacteria that produce a wide assortment of specialized small molecules. Although their natural product biosynthetic potential is high, robust molecular tools to support the heterologous expression of large biosynthetic gene clusters in Bacillus hosts are rare. Herein we adapt transformation-associated recombination (TAR) in yeast to design a single genomic capture and expression vector for antibiotic production in Bacillus subtilis. After validating this direct cloning ``plug-and-play'' approach with surfactin, we genetically interrogated amicoumacin biosynthetic gene cluster from the marine isolate Bacillus subtilis 1779. Its heterologous expression allowed us to explore an unusual maturation process involving the N-acyl-asparagine pro-drug intermediates preamicoumacins, which are hydrolyzed by the asparagine-specific peptidase into the active component amicoumacin A. This work represents the first direct cloning based heterologous expression of natural products in the model organism B. subtilis and paves the way to the development of future genome mining efforts in this genus.

  10. Directed natural product biosynthesis gene cluster capture and expression in the model bacterium Bacillus subtilis

    KAUST Repository

    Li, Yongxin

    2015-03-24

    Bacilli are ubiquitous low G+C environmental Gram-positive bacteria that produce a wide assortment of specialized small molecules. Although their natural product biosynthetic potential is high, robust molecular tools to support the heterologous expression of large biosynthetic gene clusters in Bacillus hosts are rare. Herein we adapt transformation-associated recombination (TAR) in yeast to design a single genomic capture and expression vector for antibiotic production in Bacillus subtilis. After validating this direct cloning plug-and-playa approach with surfactin, we genetically interrogated amicoumacin biosynthetic gene cluster from the marine isolate Bacillus subtilis 1779. Its heterologous expression allowed us to explore an unusual maturation process involving the N-acyl-asparagine pro-drug intermediates preamicoumacins, which are hydrolyzed by the asparagine-specific peptidase into the active component amicoumacin A. This work represents the first direct cloning based heterologous expression of natural products in the model organism B. subtilis and paves the way to the development of future genome mining efforts in this genus.

  11. Boron neutron capture therapy (BNCT) for liver metastasis: therapeutic efficacy in an experimental model

    Energy Technology Data Exchange (ETDEWEB)

    David W. Nigg

    2012-08-01

    Boron neutron capture therapy (BNCT) was proposed for untreatable colorectal liver metastases. The present study evaluates tumor control and potential radiotoxicity of BNCT in an experimental model of liver metastasis. BDIX rats were inoculated with syngeneic colon cancer cells DHD/K12/TRb. Tumor-bearing animals were divided into three groups: BPA–BNCT, boronophenylalanine (BPA) ? neutron irradiation; Beam only, neutron irradiation; Sham, matched manipulation. The total absorbed dose administered with BPA–BNCT was 13 ± 3 Gy in tumor and 9 ± 2 Gy in healthy liver. Three weeks posttreatment, the tumor surface area post-treatment/pre-treatment ratio was 0.46 ± 0.20 for BPA–BNCT, 2.7 ± 1.8 for Beam only and 4.5 ± 3.1 for Sham. The pre-treatment tumor nodule mass of 48 ± 19 mgfell significantly to 19 ± 16 mg for BPA–BNCT, but rose significantly to 140 ± 106 mg for Beam only and to 346 ± 302 mg for Sham. For both end points, the differences between the BPA–BNCT group and each of the other groups were statistically significant (ANOVA). No clinical, macroscopic or histological normal liver radiotoxicity was observed. It is concluded that BPA– BNCT induced a significant remission of experimental colorectal tumor nodules in liver with no contributory liver toxicity.

  12. Development of NASA's Models and Simulations Standard

    Science.gov (United States)

    Bertch, William J.; Zang, Thomas A.; Steele, Martin J.

    2008-01-01

    From the Space Shuttle Columbia Accident Investigation, there were several NASA-wide actions that were initiated. One of these actions was to develop a standard for development, documentation, and operation of Models and Simulations. Over the course of two-and-a-half years, a team of NASA engineers, representing nine of the ten NASA Centers developed a Models and Simulation Standard to address this action. The standard consists of two parts. The first is the traditional requirements section addressing programmatics, development, documentation, verification, validation, and the reporting of results from both the M&S analysis and the examination of compliance with this standard. The second part is a scale for evaluating the credibility of model and simulation results using levels of merit associated with 8 key factors. This paper provides an historical account of the challenges faced by and the processes used in this committee-based development effort. This account provides insights into how other agencies might approach similar developments. Furthermore, we discuss some specific applications of models and simulations used to assess the impact of this standard on future model and simulation activities.

  13. Helium Reionization Simulations. I. Modeling Quasars as Radiation Sources

    Science.gov (United States)

    La Plante, Paul; Trac, Hy

    2016-09-01

    We introduce a new project to understand helium reionization using fully coupled N-body, hydrodynamics, and radiative transfer simulations. This project aims to capture correctly the thermal history of the intergalactic medium as a result of reionization and make predictions about the Lyα forest and baryon temperature-density relation. The dominant sources of radiation for this transition are quasars, so modeling the source population accurately is very important for making reliable predictions. In this first paper, we present a new method for populating dark matter halos with quasars. Our set of quasar models includes two different light curves, a lightbulb (simple on/off) and symmetric exponential model, and luminosity-dependent quasar lifetimes. Our method self-consistently reproduces an input quasar luminosity function given a halo catalog from an N-body simulation, and propagates quasars through the merger history of halo hosts. After calibrating quasar clustering using measurements from the Baryon Oscillation Spectroscopic Survey, we find that the characteristic mass of quasar hosts is {M}h˜ 2.5× {10}12 {h}-1 {M}⊙ for the lightbulb model, and {M}h˜ 2.3× {10}12 {h}-1 {M}⊙ for the exponential model. In the latter model, the peak quasar luminosity for a given halo mass is larger than that in the former, typically by a factor of 1.5-2. The effective lifetime for quasars in the lightbulb model is 59 Myr, and in the exponential case, the effective time constant is about 15 Myr. We include semi-analytic calculations of helium reionization, and discuss how to include these quasars as sources of ionizing radiation for full hydrodynamics with radiative transfer simulations in order to study helium reionization.

  14. Capturing a Dynamic Chaperone-Substrate Interaction Using NMR-Informed Molecular Modeling.

    Science.gov (United States)

    Salmon, Loïc; Ahlstrom, Logan S; Horowitz, Scott; Dickson, Alex; Brooks, Charles L; Bardwell, James C A

    2016-08-10

    Chaperones maintain a healthy proteome by preventing aggregation and by aiding in protein folding. Precisely how chaperones influence the conformational properties of their substrates, however, remains unclear. To achieve a detailed description of dynamic chaperone-substrate interactions, we fused site-specific NMR information with coarse-grained simulations. Our model system is the binding and folding of a chaperone substrate, immunity protein 7 (Im7), with the chaperone Spy. We first used an automated procedure in which NMR chemical shifts inform the construction of system-specific force fields that describe each partner individually. The models of the two binding partners are then combined to perform simulations on the chaperone-substrate complex. The binding simulations show excellent agreement with experimental data from multiple biophysical measurements. Upon binding, Im7 interacts with a mixture of hydrophobic and hydrophilic residues on Spy's surface, causing conformational exchange within Im7 to slow down as Im7 folds. Meanwhile, the motion of Spy's flexible loop region increases, allowing for better interaction with different substrate conformations, and helping offset losses in Im7 conformational dynamics that occur upon binding and folding. Spy then preferentially releases Im7 into a well-folded state. Our strategy has enabled a residue-level description of a dynamic chaperone-substrate interaction, improving our understanding of how chaperones facilitate substrate folding. More broadly, we validate our approach using two other binding partners, showing that this approach provides a general platform from which to investigate other flexible biomolecular complexes through the integration of NMR data with efficient computational models.

  15. Modelling and Simulation of Crude Oil Dispersion

    Directory of Open Access Journals (Sweden)

    Abdulfatai JIMOH

    2006-01-01

    Full Text Available This research work was carried out to develop a model equation for the dispersion of crude oil in water. Seven different crude oils (Bonny Light, Antan Terminal, Bonny Medium, Qua Iboe Light, Brass Light Mbede, Forcados Blend and Heavy H were used as the subject crude oils. The developed model equation in this project which is given as...It was developed starting from the equation for the oil dispersion rate in water which is given as...The developed equation was then simulated with the aid of MathCAD 2000 Professional software. The experimental and model results obtained from the simulation of the model equation were plotted on the same axis against time of dispersion. The model results revealed close fittings between the experimental and the model results because the correlation coefficients and the r-square values calculated using Spreadsheet Program were both found to be unity (1.00.

  16. Continuum damage modeling and simulation of hierarchical dental enamel

    Science.gov (United States)

    Ma, Songyun; Scheider, Ingo; Bargmann, Swantje

    2016-05-01

    Dental enamel exhibits high fracture toughness and stiffness due to a complex hierarchical and graded microstructure, optimally organized from nano- to macro-scale. In this study, a 3D representative volume element (RVE) model is adopted to study the deformation and damage behavior of the fibrous microstructure. A continuum damage mechanics model coupled to hyperelasticity is developed for modeling the initiation and evolution of damage in the mineral fibers as well as protein matrix. Moreover, debonding of the interface between mineral fiber and protein is captured by employing a cohesive zone model. The dependence of the failure mechanism on the aspect ratio of the mineral fibers is investigated. In addition, the effect of the interface strength on the damage behavior is studied with respect to geometric features of enamel. Further, the effect of an initial flaw on the overall mechanical properties is analyzed to understand the superior damage tolerance of dental enamel. The simulation results are validated by comparison to experimental data from micro-cantilever beam testing at two hierarchical levels. The transition of the failure mechanism at different hierarchical levels is also well reproduced in the simulations.

  17. Simulation Modeling of Software Development Processes

    Science.gov (United States)

    Calavaro, G. F.; Basili, V. R.; Iazeolla, G.

    1996-01-01

    A simulation modeling approach is proposed for the prediction of software process productivity indices, such as cost and time-to-market, and the sensitivity analysis of such indices to changes in the organization parameters and user requirements. The approach uses a timed Petri Net and Object Oriented top-down model specification. Results demonstrate the model representativeness, and its usefulness in verifying process conformance to expectations, and in performing continuous process improvement and optimization.

  18. Design and simulation of rate-based CO2 capture processes using carbonic anhydrase (CA) applied to biogas

    DEFF Research Database (Denmark)

    Fosbøl, Philip Loldrup; Gaspar, Jozsef; Jacobsen, Bjartur

    2017-01-01

    a potential to create negative emissions using bio-energy carbon capture and storage (BECCS). All sectors are still in the need for applying more sustainable carbon capture and storage (CCS) technologies which result in lower energy consumption while reducing the impact on the environment. Recently several....... The advantage is a noticeably lower regeneration energy compared to primary and secondary amines. As a result the cost for stripping is significantly lower. Reactivated slow tertiary amines are applied in this study with the aim of reducing energy consumption. This is achieved byusing carbonic anhydrase (CA...

  19. Incorporation of RAM techniques into simulation modeling

    Energy Technology Data Exchange (ETDEWEB)

    Nelson, S.C. Jr.; Haire, M.J.; Schryver, J.C.

    1995-07-01

    This work concludes that reliability, availability, and maintainability (RAM) analytical techniques can be incorporated into computer network simulation modeling to yield an important new analytical tool. This paper describes the incorporation of failure and repair information into network simulation to build a stochastic computer model represents the RAM Performance of two vehicles being developed for the US Army: The Advanced Field Artillery System (AFAS) and the Future Armored Resupply Vehicle (FARV). The AFAS is the US Army`s next generation self-propelled cannon artillery system. The FARV is a resupply vehicle for the AFAS. Both vehicles utilize automation technologies to improve the operational performance of the vehicles and reduce manpower. The network simulation model used in this work is task based. The model programmed in this application requirements a typical battle mission and the failures and repairs that occur during that battle. Each task that the FARV performs--upload, travel to the AFAS, refuel, perform tactical/survivability moves, return to logistic resupply, etc.--is modeled. Such a model reproduces a model reproduces operational phenomena (e.g., failures and repairs) that are likely to occur in actual performance. Simulation tasks are modeled as discrete chronological steps; after the completion of each task decisions are programmed that determine the next path to be followed. The result is a complex logic diagram or network. The network simulation model is developed within a hierarchy of vehicle systems, subsystems, and equipment and includes failure management subnetworks. RAM information and other performance measures are collected which have impact on design requirements. Design changes are evaluated through ``what if`` questions, sensitivity studies, and battle scenario changes.

  20. Radiative capture reaction {sup 7}Be(p,{gamma}){sup 8}B in the continuum shell model

    Energy Technology Data Exchange (ETDEWEB)

    Bennaceur, K.; Ploszajczak, M. [Grand Accelerateur National d`Ions Lourds (GANIL), Caen (France); Nowacki, F. [Grand Accelerateur National d`Ions Lourds (GANIL), Caen (France)]|[Lab. de Physique Theorique Strasbourg, Strasbourg (France); Okolowicz, J. [Grand Accelerateur National d`Ions Lourds (GANIL), Caen (France)]|[Inst. of Nuclear Physics, Krakow (Poland)

    1998-06-01

    We present here the first application of realistic shell model (SM) including coupling between many-particle (quasi-)bound states and the continuum of one-particle scattering states to the calculation of the total capture cross section and the astrophysical factor in the reaction {sup 7}Be(p,{gamma}){sup 8}B. (orig.)

  1. Capturing natural-colour 3D models of insects for species discovery and diagnostics.

    Directory of Open Access Journals (Sweden)

    Chuong V Nguyen

    Full Text Available Collections of biological specimens are fundamental to scientific understanding and characterization of natural diversity-past, present and future. This paper presents a system for liberating useful information from physical collections by bringing specimens into the digital domain so they can be more readily shared, analyzed, annotated and compared. It focuses on insects and is strongly motivated by the desire to accelerate and augment current practices in insect taxonomy which predominantly use text, 2D diagrams and images to describe and characterize species. While these traditional kinds of descriptions are informative and useful, they cannot cover insect specimens "from all angles" and precious specimens are still exchanged between researchers and collections for this reason. Furthermore, insects can be complex in structure and pose many challenges to computer vision systems. We present a new prototype for a practical, cost-effective system of off-the-shelf components to acquire natural-colour 3D models of insects from around 3 mm to 30 mm in length. ("Natural-colour" is used to contrast with "false-colour", i.e., colour generated from, or applied to, gray-scale data post-acquisition. Colour images are captured from different angles and focal depths using a digital single lens reflex (DSLR camera rig and two-axis turntable. These 2D images are processed into 3D reconstructions using software based on a visual hull algorithm. The resulting models are compact (around 10 megabytes, afford excellent optical resolution, and can be readily embedded into documents and web pages, as well as viewed on mobile devices. The system is portable, safe, relatively affordable, and complements the sort of volumetric data that can be acquired by computed tomography. This system provides a new way to augment the description and documentation of insect species holotypes, reducing the need to handle or ship specimens. It opens up new opportunities to collect

  2. Biodistribution of sodium borocaptate (BSH) for boron neutron capture therapy (BNCT) in an oral cancer model.

    Science.gov (United States)

    Garabalino, Marcela A; Heber, Elisa M; Monti Hughes, Andrea; González, Sara J; Molinari, Ana J; Pozzi, Emiliano C C; Nievas, Susana; Itoiz, Maria E; Aromando, Romina F; Nigg, David W; Bauer, William; Trivillin, Verónica A; Schwint, Amanda E

    2013-08-01

    Boron neutron capture therapy (BNCT) is based on selective accumulation of ¹⁰B carriers in tumor followed by neutron irradiation. We previously proved the therapeutic success of BNCT mediated by the boron compounds boronophenylalanine and sodium decahydrodecaborate (GB-10) in the hamster cheek pouch oral cancer model. Based on the clinical relevance of the boron carrier sodium borocaptate (BSH) and the knowledge that the most effective way to optimize BNCT is to improve tumor boron targeting, the specific aim of this study was to perform biodistribution studies of BSH in the hamster cheek pouch oral cancer model and evaluate the feasibility of BNCT mediated by BSH at nuclear reactor RA-3. The general aim of these studies is to contribute to the knowledge of BNCT radiobiology and optimize BNCT for head and neck cancer. Sodium borocaptate (50 mg ¹⁰B/kg) was administered to tumor-bearing hamsters. Groups of 3-5 animals were killed humanely at nine time-points, 3-12 h post-administration. Samples of blood, tumor, precancerous pouch tissue, normal pouch tissue and other clinically relevant normal tissues were processed for boron measurement by optic emission spectroscopy. Tumor boron concentration peaked to therapeutically useful boron concentration values of 24-35 ppm. The boron concentration ratio tumor/normal pouch tissue ranged from 1.1 to 1.8. Pharmacokinetic curves showed that the optimum interval between BSH administration and neutron irradiation was 7-11 h. It is concluded that BNCT mediated by BSH at nuclear reactor RA-3 would be feasible.

  3. Capturing natural-colour 3D models of insects for species discovery and diagnostics.

    Science.gov (United States)

    Nguyen, Chuong V; Lovell, David R; Adcock, Matt; La Salle, John

    2014-01-01

    Collections of biological specimens are fundamental to scientific understanding and characterization of natural diversity-past, present and future. This paper presents a system for liberating useful information from physical collections by bringing specimens into the digital domain so they can be more readily shared, analyzed, annotated and compared. It focuses on insects and is strongly motivated by the desire to accelerate and augment current practices in insect taxonomy which predominantly use text, 2D diagrams and images to describe and characterize species. While these traditional kinds of descriptions are informative and useful, they cannot cover insect specimens "from all angles" and precious specimens are still exchanged between researchers and collections for this reason. Furthermore, insects can be complex in structure and pose many challenges to computer vision systems. We present a new prototype for a practical, cost-effective system of off-the-shelf components to acquire natural-colour 3D models of insects from around 3 mm to 30 mm in length. ("Natural-colour" is used to contrast with "false-colour", i.e., colour generated from, or applied to, gray-scale data post-acquisition.) Colour images are captured from different angles and focal depths using a digital single lens reflex (DSLR) camera rig and two-axis turntable. These 2D images are processed into 3D reconstructions using software based on a visual hull algorithm. The resulting models are compact (around 10 megabytes), afford excellent optical resolution, and can be readily embedded into documents and web pages, as well as viewed on mobile devices. The system is portable, safe, relatively affordable, and complements the sort of volumetric data that can be acquired by computed tomography. This system provides a new way to augment the description and documentation of insect species holotypes, reducing the need to handle or ship specimens. It opens up new opportunities to collect data for research

  4. Testing turbulent closure models with convection simulations

    CERN Document Server

    Snellman, J E; Mantere, M J; Rheinhardt, M; Dintrans, B

    2012-01-01

    Aims: To compare simple analytical closure models of turbulent Boussinesq convection for stellar applications with direct three-dimensional simulations both in homogeneous and inhomogeneous (bounded) setups. Methods: We use simple analytical closure models to compute the fluxes of angular momentum and heat as a function of rotation rate measured by the Taylor number. We also investigate cases with varying angles between the angular velocity and gravity vectors, corresponding to locating the computational domain at different latitudes ranging from the pole to the equator of the star. We perform three-dimensional numerical simulations in the same parameter regimes for comparison. The free parameters appearing in the closure models are calibrated by two fit methods using simulation data. Unique determination of the closure parameters is possible only in the non-rotating case and when the system is placed at the pole. In the other cases the fit procedures yield somewhat differing results. The quality of the closu...

  5. Analyzing Strategic Business Rules through Simulation Modeling

    Science.gov (United States)

    Orta, Elena; Ruiz, Mercedes; Toro, Miguel

    Service Oriented Architecture (SOA) holds promise for business agility since it allows business process to change to meet new customer demands or market needs without causing a cascade effect of changes in the underlying IT systems. Business rules are the instrument chosen to help business and IT to collaborate. In this paper, we propose the utilization of simulation models to model and simulate strategic business rules that are then disaggregated at different levels of an SOA architecture. Our proposal is aimed to help find a good configuration for strategic business objectives and IT parameters. The paper includes a case study where a simulation model is built to help business decision-making in a context where finding a good configuration for different business parameters and performance is too complex to analyze by trial and error.

  6. Modeling and simulation with operator scaling

    CERN Document Server

    Cohen, Serge; Rosinski, Jan

    2009-01-01

    Self-similar processes are useful in modeling diverse phenomena that exhibit scaling properties. Operator scaling allows a different scale factor in each coordinate. This paper develops practical methods for modeling and simulating stochastic processes with operator scaling. A simulation method for operator stable Levy processes is developed, based on a series representation, along with a Gaussian approximation of the small jumps. Several examples are given to illustrate practical applications. A classification of operator stable Levy processes in two dimensions is provided according to their exponents and symmetry groups. We conclude with some remarks and extensions to general operator self-similar processes.

  7. Hemispherical sky simulator for daylighting model studies

    Energy Technology Data Exchange (ETDEWEB)

    Selkowitz, S.

    1981-07-01

    The design of a 24-foot-diameter hemispherical sky simulator recently completed at LBL is described. The goal was to produce a facility in which large models could be tested; which was suitable for research, teaching, and design; which could provide a uniform sky, an overcast sky, and several clear-sky luminance distributions, as well as accommodating an artificial sun. Initial operating experience with the facility is described, the sky simulator capabilities are reviewed, and its strengths and weaknesses relative to outdoor modeling tests are discussed.

  8. Wind Shear Target Echo Modeling and Simulation

    Directory of Open Access Journals (Sweden)

    Xiaoyang Liu

    2015-01-01

    Full Text Available Wind shear is a dangerous atmospheric phenomenon in aviation. Wind shear is defined as a sudden change of speed or direction of the wind. In order to analyze the influence of wind shear on the efficiency of the airplane, this paper proposes a mathematical model of point target rain echo and weather target signal echo based on Doppler effect. The wind field model is developed in this paper, and the antenna model is also studied by using Bessel function. The spectrum distribution of symmetric and asymmetric wind fields is researched by using the mathematical model proposed in this paper. The simulation results are in accordance with radial velocity component, and the simulation results also confirm the correctness of the established model of antenna.

  9. Theoretical simulation of CO2 capture by an \\text{A}{{\\text{l}}_{11}}\\text{Mg}_{3}^{-} cluster

    Science.gov (United States)

    Jiang, Yuanyuan; Xie, Xuefang; Hamid, Ilyar; Chen, Chu; Duan, Haiming

    2017-04-01

    In order to have an impact on carbon emissions, new stable materials for carbon capture should be able to adsorb CO2 from a mixture of other gases efficiently. Based on density functional theory calculations, we showed that the \\text{A}{{\\text{l}}11}\\text{Mg}3- cluster has an excellent capture capacity of CO2 and high CO2 selectivity under ambient conditions. \\text{A}{{\\text{l}}11}\\text{Mg}3- has an O2-resist property because this cluster is similar to \\text{Al}13- which contains 40 electrons with a larger energy gap. The \\text{A}{{\\text{l}}11}\\text{Mg}3- cluster prefers to adsorb CO2 compared with CH4, H2 and N2, and the CO2 molecule can be chemically adsorbed on the cluster by overcoming a lower barrier, which originates from the introduction of the Mg atom. When seven CO2 molecules are chemically adsorbed on the cluster, the capture capacity of CO2 can reach up to 18.99 mol kg-1 this means that the \\text{A}{{\\text{l}}11}\\text{Mg}3- cluster can be viewed as a potential candidate material for CO2 capture.

  10. Nuclear reactor core modelling in multifunctional simulators

    Energy Technology Data Exchange (ETDEWEB)

    Puska, E.K. [VTT Energy, Nuclear Energy, Espoo (Finland)

    1999-06-01

    The thesis concentrates on the development of nuclear reactor core models for the APROS multifunctional simulation environment and the use of the core models in various kinds of applications. The work was started in 1986 as a part of the development of the entire APROS simulation system. The aim was to create core models that would serve in a reliable manner in an interactive, modular and multifunctional simulator/plant analyser environment. One-dimensional and three-dimensional core neutronics models have been developed. Both models have two energy groups and six delayed neutron groups. The three-dimensional finite difference type core model is able to describe both BWR- and PWR-type cores with quadratic fuel assemblies and VVER-type cores with hexagonal fuel assemblies. The one- and three-dimensional core neutronics models can be connected with the homogeneous, the five-equation or the six-equation thermal hydraulic models of APROS. The key feature of APROS is that the same physical models can be used in various applications. The nuclear reactor core models of APROS have been built in such a manner that the same models can be used in simulator and plant analyser applications, as well as in safety analysis. In the APROS environment the user can select the number of flow channels in the three-dimensional reactor core and either the homogeneous, the five- or the six-equation thermal hydraulic model for these channels. The thermal hydraulic model and the number of flow channels have a decisive effect on the calculation time of the three-dimensional core model and thus, at present, these particular selections make the major difference between a safety analysis core model and a training simulator core model. The emphasis on this thesis is on the three-dimensional core model and its capability to analyse symmetric and asymmetric events in the core. The factors affecting the calculation times of various three-dimensional BWR, PWR and WWER-type APROS core models have been

  11. Battery thermal models for hybrid vehicle simulations

    Science.gov (United States)

    Pesaran, Ahmad A.

    This paper summarizes battery thermal modeling capabilities for: (1) an advanced vehicle simulator (ADVISOR); and (2) battery module and pack thermal design. The National Renewable Energy Laboratory's (NREL's) ADVISOR is developed in the Matlab/Simulink environment. There are several battery models in ADVISOR for various chemistry types. Each one of these models requires a thermal model to predict the temperature change that could affect battery performance parameters, such as resistance, capacity and state of charges. A lumped capacitance battery thermal model in the Matlab/Simulink environment was developed that included the ADVISOR battery performance models. For thermal evaluation and design of battery modules and packs, NREL has been using various computer aided engineering tools including commercial finite element analysis software. This paper will discuss the thermal ADVISOR battery model and its results, along with the results of finite element modeling that were presented at the workshop on "Development of Advanced Battery Engineering Models" in August 2001.

  12. Computational Modeling of Mixed Solids for CO2 CaptureSorbents

    Energy Technology Data Exchange (ETDEWEB)

    Duan, Yuhua

    2015-01-01

    Since current technologies for capturing CO2 to fight global climate change are still too energy intensive, there is a critical need for development of new materials that can capture CO2 reversibly with acceptable energy costs. Accordingly, solid sorbents have been proposed to be used for CO2 capture applications through a reversible chemical transformation. By combining thermodynamic database mining with first principles density functional theory and phonon lattice dynamics calculations, a theoretical screening methodology to identify the most promising CO2 sorbent candidates from the vast array of possible solid materials has been proposed and validated. The calculated thermodynamic properties of different classes of solid materials versus temperature and pressure changes were further used to evaluate the equilibrium properties for the CO2 adsorption/desorption cycles. According to the requirements imposed by the pre- and post- combustion technologies and based on our calculated thermodynamic properties for the CO2 capture reactions by the solids of interest, we were able to screen only those solid materials for which lower capture energy costs are expected at the desired pressure and temperature conditions. Only those selected CO2 sorbent candidates were further considered for experimental validations. The ab initio thermodynamic technique has the advantage of identifying thermodynamic properties of CO2 capture reactions without any experimental input beyond crystallographic structural information of the solid phases involved. Such methodology not only can be used to search for good candidates from existing database of solid materials, but also can provide some guidelines for synthesis new materials. In this presentation, we apply our screening methodology to mixing solid systems to adjust the turnover temperature to help on developing CO2 capture Technologies.

  13. Feasibility study of CO2 capture by anti-sublimation

    NARCIS (Netherlands)

    Schach, M.O.; Oyarzun, B.A.; Schramm, H.; Schneider, R.; Repke, J.U.

    2011-01-01

    Processes for carbon capture and storage have the drawback of high energy demand. In this work the application of CO2 capture by anti-sublimation is analyzed. The process was simulated using Aspen Plus. Process description is accomplished by phase equilibria models which are able to reproduce the

  14. Feasibility study of CO2 capture by anti-sublimation

    NARCIS (Netherlands)

    Schach, M.O.; Oyarzun, B.A.; Schramm, H.; Schneider, R.; Repke, J.U.

    2011-01-01

    Processes for carbon capture and storage have the drawback of high energy demand. In this work the application of CO2 capture by anti-sublimation is analyzed. The process was simulated using Aspen Plus. Process description is accomplished by phase equilibria models which are able to reproduce the va

  15. Kanban simulation model for production process optimization

    Directory of Open Access Journals (Sweden)

    Golchev Riste

    2015-01-01

    Full Text Available A long time has passed since the KANBAN system has been established as an efficient method for coping with the excessive inventory. Still, the possibilities for its improvement through its integration with other different approaches should be investigated further. The basic research challenge of this paper is to present benefits of KANBAN implementation supported with Discrete Event Simulation (DES. In that direction, at the beginning, the basics of KANBAN system are presented with emphasis on the information and material flow, together with a methodology for implementation of KANBAN system. Certain analysis on combining the simulation with this methodology is presented. The paper is concluded with a practical example which shows that through understanding the philosophy of the implementation methodology of KANBAN system and the simulation methodology, a simulation model can be created which can serve as a basis for a variety of experiments that can be conducted within a short period of time, resulting with production process optimization.

  16. The Anti-Proliferative Effect of Boron Neutron Capture Therapy in a Prostate Cancer Xenograft Model.

    Directory of Open Access Journals (Sweden)

    Kiyoshi Takahara

    Full Text Available Boron neutron capture therapy (BNCT is a selective radiation treatment for tumors that preferentially accumulate drugs carrying the stable boron isotope, 10B. BNCT has been evaluated clinically as an alternative to conventional radiation therapy for the treatment of brain tumors, and more recently, recurrent advanced head and neck cancer. Here we investigated the effect of BNCT on prostate cancer (PCa using an in vivo mouse xenograft model that we have developed.Mice bearing the xenotransplanted androgen-independent human PCa cell line, PC3, were divided into four groups: Group 1: untreated controls; Group 2: Boronophenylalanine (BPA; Group 3: neutron; Group 4: BPA-mediated BNCT. We compared xenograft growth among these groups, and the body weight and any motility disturbance were recorded. Immunohistochemical (IHC studies of the proliferation marker, Ki-67, and TUNEL staining were performed 9 weeks after treatment.The in vivo studies demonstrated that BPA-mediated BNCT significantly delayed tumor growth in comparison with the other groups, without any severe adverse events. There was a significant difference in the rate of freedom from gait abnormalities between the BPA-mediated BNCT group and the other groups. The IHC studies revealed that BNCT treatment significantly reduced the number of Ki-67-positive cells in comparison with the controls (mean ± SD 6.9 ± 1.5 vs 12.7 ± 4.0, p<0.05, while there was no difference in the number of apoptotic cells, suggesting that BPA-mediated BNCT reduced PCa progression without affecting apoptosis at 9 weeks post-treatment.This study has provided the first preclinical proof-of-principle data to indicate that BPA-mediated BNCT reduces the in vivo growth of PCa. Although further studies will be necessary, BNCT might be a novel potential treatment for PCa.

  17. Kuang's Semi-Classical Formalism for Calculating Electron Capture Cross Sections and Sample Application for ENA Modeling

    Science.gov (United States)

    Barghouty, A. F.

    2013-01-01

    Accurate estimates of electron-capture cross sections at energies relevant to ENA modeling (approx. few MeV per nucleon) and for multi-electron ions must rely on detailed, but computationally expensive, quantummechanical description of the collision process. Kuang's semi-classical approach is an elegant and efficient way to arrive at these estimates. Motivated by ENA modeling efforts, we shall briefly present this approach along with sample applications and report on current progress.

  18. A Computational Model for Simulating Spaceflight Induced Bone Remodeling

    Science.gov (United States)

    Pennline, James A.; Mulugeta, Lealem

    2014-01-01

    An overview of an initial development of a model of bone loss due to skeletal unloading in weight bearing sites is presented. The skeletal site chosen for the initial application of the model is the femoral neck region because hip fractures can be debilitating to the overall performance health of astronauts. The paper begins with the motivation for developing such a model of the time course of change in bone in order to understand the mechanism of bone demineralization experienced by astronauts in microgravity, to quantify the health risk, and to establish countermeasures. Following this, a general description of a mathematical formulation of the process of bone remodeling is discussed. Equations governing the rate of change of mineralized bone volume fraction and active osteoclast and osteoblast are illustrated. Some of the physiology of bone remodeling, the theory of how imbalance in remodeling can cause bone loss, and how the model attempts to capture this is discussed. The results of a preliminary validation analysis that was carried out are presented. The analysis compares a set of simulation results against bone loss data from control subjects who participated in two different bed rest studies. Finally, the paper concludes with outlining the current limitations and caveats of the model, and planned future work to enhance the state of the model.

  19. Neutron Capture Nucleosynthesis

    CERN Document Server

    Kiss, Miklos

    2016-01-01

    Heavy elements (beyond iron) are formed in neutron capture nucleosynthesis processes. We have proposed a simple unified model to investigate the neutron capture nucleosynthesis in arbitrary neutron density environment. We have also investigated what neutron density is required to reproduce the measured abundance of nuclei assuming equilibrium processes. We found both of these that the medium neutron density has a particularly important role at neutron capture nucleosynthesis. About these results most of the nuclei can formed at medium neutron capture density environment e.g. in some kind of AGB stars. Besides these observations our model is capable to use educational purpose.

  20. EXACT SIMULATION OF A BOOLEAN MODEL

    Directory of Open Access Journals (Sweden)

    Christian Lantuéjoul

    2013-06-01

    Full Text Available A Boolean model is a union of independent objects (compact random subsets located at Poisson points. Two algorithms are proposed for simulating a Boolean model in a bounded domain. The first one applies only to stationary models. It generates the objects prior to their Poisson locations. Two examples illustrate its applicability. The second algorithm applies to stationary and non-stationary models. It generates the Poisson points prior to the objects. Its practical difficulties of implementation are discussed. Both algorithms are based on importance sampling techniques, and the generated objects are weighted.

  1. Biological transportation networks: Modeling and simulation

    KAUST Repository

    Albi, Giacomo

    2015-09-15

    We present a model for biological network formation originally introduced by Cai and Hu [Adaptation and optimization of biological transport networks, Phys. Rev. Lett. 111 (2013) 138701]. The modeling of fluid transportation (e.g., leaf venation and angiogenesis) and ion transportation networks (e.g., neural networks) is explained in detail and basic analytical features like the gradient flow structure of the fluid transportation network model and the impact of the model parameters on the geometry and topology of network formation are analyzed. We also present a numerical finite-element based discretization scheme and discuss sample cases of network formation simulations.

  2. Modeling and Simulation of Nuclear Fuel Materials

    Energy Technology Data Exchange (ETDEWEB)

    Devanathan, Ramaswami; Van Brutzel, Laurent; Chartier, Alan; Gueneau, Christine; Mattsson, Ann E.; Tikare, Veena; Bartel, Timothy; Besmann, T. M.; Stan, Marius; Van Uffelen, Paul

    2010-10-01

    We review the state of modeling and simulation of nuclear fuels with emphasis on the most widely used nuclear fuel, UO2. The hierarchical scheme presented represents a science-based approach to modeling nuclear fuels by progressively passing information in several stages from ab initio to continuum levels. Such an approach is essential to overcome the challenges posed by radioactive materials handling, experimental limitations in modeling extreme conditions and accident scenarios, and the small time and distance scales of fundamental defect processes. When used in conjunction with experimental validation, this multiscale modeling scheme can provide valuable guidance to development of fuel for advanced reactors to meet rising global energy demand.

  3. Simulation modeling of health care policy.

    Science.gov (United States)

    Glied, Sherry; Tilipman, Nicholas

    2010-01-01

    Simulation modeling of health reform is a standard part of policy development and, in the United States, a required element in enacting health reform legislation. Modelers use three types of basic structures to build models of the health system: microsimulation, individual choice, and cell-based. These frameworks are filled in with data on baseline characteristics of the system and parameters describing individual behavior. Available data on baseline characteristics are imprecise, and estimates of key empirical parameters vary widely. A comparison of estimated and realized consequences of several health reform proposals suggests that models provided reasonably accurate estimates, with confidence bounds of approximately 30%.

  4. A Self-Assessment Stereo Capture Model Applicable to the Internet of Things.

    Science.gov (United States)

    Lin, Yancong; Yang, Jiachen; Lv, Zhihan; Wei, Wei; Song, Houbing

    2015-08-21

    The realization of the Internet of Things greatly depends on the information communication among physical terminal devices and informationalized platforms, such as smart sensors, embedded systems and intelligent networks. Playing an important role in information acquisition, sensors for stereo capture have gained extensive attention in various fields. In this paper, we concentrate on promoting such sensors in an intelligent system with self-assessment capability to deal with the distortion and impairment in long-distance shooting applications. The core design is the establishment of the objective evaluation criteria that can reliably predict shooting quality with different camera configurations. Two types of stereo capture systems-toed-in camera configuration and parallel camera configuration-are taken into consideration respectively. The experimental results show that the proposed evaluation criteria can effectively predict the visual perception of stereo capture quality for long-distance shooting.

  5. Modeling and simulation of epidemic spread

    DEFF Research Database (Denmark)

    Shatnawi, Maad; Lazarova-Molnar, Sanja; Zaki, Nazar

    2013-01-01

    and control such epidemics. This paper presents an overview of the epidemic spread modeling and simulation, and summarizes the main technical challenges in this field. It further investigates the most relevant recent approaches carried out towards this perspective and provides a comparison and classification...

  6. Object Oriented Modelling and Dynamical Simulation

    DEFF Research Database (Denmark)

    Wagner, Falko Jens; Poulsen, Mikael Zebbelin

    1998-01-01

    This report with appendix describes the work done in master project at DTU.The goal of the project was to develop a concept for simulation of dynamical systems based on object oriented methods.The result was a library of C++-classes, for use when both building componentbased models and when...

  7. Modeling and Simulating Virtual Anatomical Humans

    NARCIS (Netherlands)

    Madehkhaksar, Forough; Luo, Zhiping; Pronost, Nicolas; Egges, Arjan

    2014-01-01

    This chapter presents human musculoskeletal modeling and simulation as a challenging field that lies between biomechanics and computer animation. One of the main goals of computer animation research is to develop algorithms and systems that produce plausible motion. On the other hand, the main chall

  8. Modeling and Simulation in Healthcare Future Directions

    Science.gov (United States)

    2010-07-13

    Quantify performance (Competency - based) 6. Simulate before practice ( Digital Libraries ) Classic Education and Examination What is the REVOLUTION in...av $800,000 yr 2.) Actor patients - $250,000 – $400,000/yr 2. Digital Libraries or synthetic tissue models a. Subscription vs up-front costs

  9. Simulation Versus Models: Which One and When?

    Science.gov (United States)

    Dorn, William S.

    1975-01-01

    Describes two types of computer-based experiments: simulation (which assumes no student knowledge of the workings of the computer program) is recommended for experiments aimed at inductive reasoning; and modeling (which assumes student understanding of the computer program) is recommended for deductive processes. (MLH)

  10. Love Kills:. Simulations in Penna Ageing Model

    Science.gov (United States)

    Stauffer, Dietrich; Cebrat, Stanisław; Penna, T. J. P.; Sousa, A. O.

    The standard Penna ageing model with sexual reproduction is enlarged by adding additional bit-strings for love: Marriage happens only if the male love strings are sufficiently different from the female ones. We simulate at what level of required difference the population dies out.

  11. Inverse modeling for Large-Eddy simulation

    NARCIS (Netherlands)

    Geurts, Bernardus J.

    1998-01-01

    Approximate higher order polynomial inversion of the top-hat filter is developed with which the turbulent stress tensor in Large-Eddy Simulation can be consistently represented using the filtered field. Generalized (mixed) similarity models are proposed which improved the agreement with the kinetic

  12. Microdata Simulation Modeling After Twenty Years.

    Science.gov (United States)

    Haveman, Robert H.

    1986-01-01

    This article describes the method and the development of microdata simulation modeling over the past two decades. After tracing a brief history of this evaluation method, its problems and prospects are assessed. The effects of this research method on the development of the social sciences are examined. (JAZ)

  13. Simulation Modeling on the Macintosh using STELLA.

    Science.gov (United States)

    Costanza, Robert

    1987-01-01

    Describes a new software package for the Apple Macintosh computer which can be used to create elaborate simulation models in a fraction of the time usually required without using a programming language. Illustrates the use of the software which relates to water usage. (TW)

  14. Simulation Modeling of Radio Direction Finding Results

    Directory of Open Access Journals (Sweden)

    K. Pelikan

    1994-12-01

    Full Text Available It is sometimes difficult to determine analytically error probabilities of direction finding results for evaluating algorithms of practical interest. Probalistic simulation models are described in this paper that can be to study error performance of new direction finding systems or to geographical modifications of existing configurations.

  15. Coarse-grained rigid blob model for soft matter simulations

    Science.gov (United States)

    Chao, Sheng D.; Kress, Joel D.; Redondo, Antonio

    2005-06-01

    We have developed a coarse-grained multiscale molecular simulation method for soft matter systems that directly incorporates stereochemical information. We divide the material into disjoint groups of atoms or particles that move as separate rigid bodies; we call these groups "rigid blobs," hence the name coarse-grained rigid blob model. The method is enabled by the construction of transferable interblob potentials that approximate the net intermolecular interactions, as obtained from ab initio electronic structure calculations, other all-atom empirical potentials, experimental data, or any combination of the above. We utilize a multipolar expansion to obtain the interblob potential-energy functions. The series, which contains controllable approximations that allow us to estimate the errors, approaches the original intermolecular potential as the number of terms increases. Using a novel numerical algorithm, we can calculate the interblob potentials very efficiently in terms of a few interaction moment tensors. This reduces the labor well beyond what is required in standard molecular-dynamics calculations and allows large-scale simulations for temporal scales commensurate with characteristic times of nano- and mesoscale systems. A detailed derivation of the formulas is presented, followed by illustrative applications to several systems showing that the method can effectively capture realistic microscopic details and can easily extend to large-scale simulations.

  16. A Prison/Parole System Simulation Model,

    Science.gov (United States)

    parole system on future prison and parole populations. A simulation model is presented, viewing a prison / parole system as a feedback process for...ciminal offenders . Transitions among the states in which an offender might be located, imprisoned, paroled , and discharged, are assumed to be in...accordance with a discrete time semi-Markov process. Projected prison and parole populations for sample data and applications of the model are discussed. (Author)

  17. Modeling visible and near-infrared snow surface reflectance-simulation and validation

    Institute of Scientific and Technical Information of China (English)

    Hongyi Wu; Ling Tong

    2011-01-01

    Retrieving snow surface reflectance is difficult in optical remote sensing.Hence,this letter evaluates five surface reflectance models,including the Ross-Li,Roujean,Walthall,modified Rahman and Staylor models,in terms of their capacities to capture snow reflectance signatures using ground measurements in Antarctica.The biases of all the models are less than 0.0003 in both visible and near-infrared regions.Moreover,with the exception of the Staylor model,all models have root-mean-square errors of around 0.02,indicating that they can simulate the reflectance magnitude well.The R2 performances of the Ross-Li and Roujean models are higher than those of the others,indicating that these two models can capture the angle distribution of snow surface reflectance better.The bidirectional reflectance distribution flmction (BRDF) characterizes the angular distribution of surface reflection[1,2].It plays an important role in performing atmospheric correction,detecting land cover types,and calculating other biophysical parameters[3].Howcver,the retrieval of snow BRDF/albedo is always a difficult issue in the application of remotely sensed information.%Retrieving snow surface reflectance is difficult in optical remote sensing. Hence, this letter evaluates five surface reflectance models, including the Ross-Li, Roujean, Walthall, modified Rahman and Staylor models, in terms of their capacities to capture snow reflectance signatures using ground measurements in Antarctica. The biases of all the models are less than 0.0003 in both visible and near-infrared regions. Moreover, with the exception of the Staylor model, all models have root-mean-square errors of around 0.02, indicating that they can simulate the reflectance magnitude well. The R2 performances of the Ross-Li and Roujean models are higher than those of the others, indicating that these two models can capture the angle distribution of snow surface reflectance better.

  18. Molecular dynamics study of ion capture from water by a model ionophore, tetraprotonated cryptand SC24

    Science.gov (United States)

    Owenson, Brian; Macelroy, Robert D.; Pohorille, Andrew

    1988-01-01

    The molecular dynamics of chloride capture from water by the tetraprotonated cryptand SC24 has been studied for the cases of 19 distances between the criptand and the chloride. The chloride capture is found to be characterized by a rapid cooperative change in the conformation of the cryptand when the Cl(-) begins to enter the ligand and just as it encounters the energy barrier. The conformational transition is associated with a shift of three N-H bonds from the pure endo orientation, such that they point toward the chloride.

  19. Molecular dynamics study of ion capture from water by a model ionophore, tetraprotonated cryptand SC24

    Science.gov (United States)

    Owenson, Brian; Macelroy, Robert D.; Pohorille, Andrew

    1988-01-01

    The molecular dynamics of chloride capture from water by the tetraprotonated cryptand SC24 has been studied for the cases of 19 distances between the criptand and the chloride. The chloride capture is found to be characterized by a rapid cooperative change in the conformation of the cryptand when the Cl(-) begins to enter the ligand and just as it encounters the energy barrier. The conformational transition is associated with a shift of three N-H bonds from the pure endo orientation, such that they point toward the chloride.

  20. Modeling of phonon- and Coulomb-mediated capture processes in quantum dots

    DEFF Research Database (Denmark)

    Magnúsdóttir, Ingibjörg

    2003-01-01

    of higher dimensionality. Here, we investigate carrier capture processes into quantum dots, mediated by emission of one and two LO phonons. In these investigations is is assumed that the dot is empty initially. In the Case of single-phonon capture we also investigate the influence of the presence...... are performed by assuming that the incident carrier is a free carrier described by a plane wave. Therefore, the influence of waves are scattered by the quantum dot have been neglected. At certain wavelengths and dot sizes, the quantum dot can act as a Fabry-Perot mirror in which the incident carrier travels...

  1. Dynamic simulation and analysis of a pilot-scale CO2 post-combustion capture unit using piperazine and MEA

    DEFF Research Database (Denmark)

    Gaspar, Jozsef; Ricardez-Sandoval, Luis; Jørgensen, John Bagterp

    2016-01-01

    show the results for the baseline 30 wt% MEA and the low energy piperazine (PZ) solutions. This analysis reveals that the absorber reaches steady-state faster using MEA compared to PZ. This is related to the shift of the mass transfer zone due to changes in temperature. The transient operation...... in the regeneration unit is somewhat similar while using both solvents: an initial fast decrease of the lean loading is followed by a slow transient period as the system approaches steady-state conditions. We show the presence of inverse response in the stripper column when the rich loading decreases or the feed......Post-combustion capture is a promising technology-for developing CO2 neutral power plants. However, to make it economically and technically feasible, capture plants must follow the fast and large load changes of the power plants without decreasing the overall performance of the plant. Dynamic...

  2. Simulation of atmospheric aerosols in East Asia using modeling system RAMS-CMAQ: Model evaluation

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    The modeling system RAMS-CMAQ is applied in this paper to East Asia to simulate the temporo-spatial concentration distributions of atmospheric aerosols. For evaluating its performances, modeled concentrations of aerosols such as sulfate, nitrate, ammonium, black carbon and organic carbon were compared with observations obtained in East Asia on board of two aircrafts in the springtime of 2001. The comparison showed generally good agreement, and, in particular, that the modeling system captured most of the important observed features, including vertical gradients of the aerosols of the Asian outflow over the western Pacific. The evaluation results provide us with much confidence for further use of the modeling system to investigate the transport and transformation processes of atmospheric aerosols over East Asia and to assess their impacts on the Earth's radiation budget.

  3. Comparison of Thunderstorm Simulations from WRF-NMM and WRF-ARW Models over East Indian Region

    Directory of Open Access Journals (Sweden)

    A. J. Litta

    2012-01-01

    Full Text Available The thunderstorms are typical mesoscale systems dominated by intense convection. Mesoscale models are essential for the accurate prediction of such high-impact weather events. In the present study, an attempt has been made to compare the simulated results of three thunderstorm events using NMM and ARW model core of WRF system and validated the model results with observations. Both models performed well in capturing stability indices which are indicators of severe convective activity. Comparison of model-simulated radar reflectivity imageries with observations revealed that NMM model has simulated well the propagation of the squall line, while the squall line movement was slow in ARW. From the model-simulated spatial plots of cloud top temperature, we can see that NMM model has better captured the genesis, intensification, and propagation of thunder squall than ARW model. The statistical analysis of rainfall indicates the better performance of NMM than ARW. Comparison of model-simulated thunderstorm affected parameters with that of the observed showed that NMM has performed better than ARW in capturing the sharp rise in humidity and drop in temperature. This suggests that NMM model has the potential to provide unique and valuable information for severe thunderstorm forecasters over east Indian region.

  4. Lean NOx Trap Modeling in Vehicle Systems Simulations

    Energy Technology Data Exchange (ETDEWEB)

    Gao, Zhiming [ORNL; Chakravarthy, Veerathu K [ORNL; Daw, C Stuart [ORNL; Conklin, Jim [ORNL

    2010-09-01

    A one-dimensional model for simulating lean NOx trap (LNT) performance is developed and validated using both steady state cycling data and transient data from FTP testing cycles. The model consists of the conservation equations for chemical species and energy in the bulk flow, energy of the solid walls, O2 storage and NOx storage (in the form of nitrites and nitrates). Nitrites and nitrates are formed by diffusion of NO and NO2, respectively, into sorbent particles (assumed to be hemi-spherical in shape) along with O2 and their formation rates are controlled by chemical kinetics as well as solid-phase diffusion rates of NOx species. The model also accounts for thermal aging and sulfation of LNTs. Empirical correlations are developed on the basis of published experimental data to capture these effects. These empirical correlations depend on total mileage for which the LNT has been in use, the mileage accumulated since the last desulfation event in addition to the freshly degreened catalyst characteristics. The model has been used in studies of vehicle systems (integration, performance etc.) including hybrid powertrain configurations. Since the engines in hybrid vehicles turn on and off multiple number of times during single drive cycles, the exhaust systems may encounter multiple cold start transients. Accurate modeling of catalyst warm-up and cooling is, therefore, very important to simulate LNT performance in such vehicles. For this purpose, the convective heat loss from the LNT to the ambient is modeled using a Nusselt number correlation that includes effects of both forced convection and natural convection (with later being important when vehicle is stationary). Using the model, the fuel penalty associated with operating LNTs on small diesel engine powered car during FTP drive cycles is estimated.

  5. Twitter's tweet method modelling and simulation

    Science.gov (United States)

    Sarlis, Apostolos S.; Sakas, Damianos P.; Vlachos, D. S.

    2015-02-01

    This paper seeks to purpose the concept of Twitter marketing methods. The tools that Twitter provides are modelled and simulated using iThink in the context of a Twitter media-marketing agency. The paper has leveraged the system's dynamic paradigm to conduct Facebook marketing tools and methods modelling, using iThink™ system to implement them. It uses the design science research methodology for the proof of concept of the models and modelling processes. The following models have been developed for a twitter marketing agent/company and tested in real circumstances and with real numbers. These models were finalized through a number of revisions and iterators of the design, develop, simulate, test and evaluate. It also addresses these methods that suit most organized promotion through targeting, to the Twitter social media service. The validity and usefulness of these Twitter marketing methods models for the day-to-day decision making are authenticated by the management of the company organization. It implements system dynamics concepts of Twitter marketing methods modelling and produce models of various Twitter marketing situations. The Tweet method that Twitter provides can be adjusted, depending on the situation, in order to maximize the profit of the company/agent.

  6. Kane Method Based Dynamics Modeling and Control Study for Space Manipulator Capturing a Space Target

    Directory of Open Access Journals (Sweden)

    Yanhua Han

    2016-01-01

    Full Text Available Dynamics modeling and control problem of a two-link manipulator mounted on a spacecraft (so-called carrier freely flying around a space target on earth’s circular orbit is studied in the paper. The influence of the carrier’s relative movement on its manipulator is considered in dynamics modeling; nevertheless, that of the manipulator on its carrier is neglected with the assumption that the mass and inertia moment of the manipulator is far less than that of the carrier. Meanwhile, we suppose that the attitude control system of the carrier guarantees its side on which the manipulator is mounted points accurately always the space target during approaching operation. The ideal constraint forces can be out of consideration in dynamics modeling as Kane method is used. The path functions of the manipulator’s end-effector approaching the space target as well as the manipulator’s joints control torque functions are programmed to meet the soft touch requirement that the end-effector’s relative velocity to the space target is zero at touch moment. Numerical simulation validation is conducted finally.

  7. Anatomy and Physiology of Multiscale Modeling and Simulation in Systems Medicine.

    Science.gov (United States)

    Mizeranschi, Alexandru; Groen, Derek; Borgdorff, Joris; Hoekstra, Alfons G; Chopard, Bastien; Dubitzky, Werner

    2016-01-01

    Systems medicine is the application of systems biology concepts, methods, and tools to medical research and practice. It aims to integrate data and knowledge from different disciplines into biomedical models and simulations for the understanding, prevention, cure, and management of complex diseases. Complex diseases arise from the interactions among disease-influencing factors across multiple levels of biological organization from the environment to molecules. To tackle the enormous challenges posed by complex diseases, we need a modeling and simulation framework capable of capturing and integrating information originating from multiple spatiotemporal and organizational scales. Multiscale modeling and simulation in systems medicine is an emerging methodology and discipline that has already demonstrated its potential in becoming this framework. The aim of this chapter is to present some of the main concepts, requirements, and challenges of multiscale modeling and simulation in systems medicine.

  8. Comparison of two electrolyte models for the carbon capture with aqueous ammonia

    DEFF Research Database (Denmark)

    Darde, Victor; Thomsen, Kaj; van Well, Willy J.M.

    2012-01-01

    Post-combustion carbon capture is attracting much attention due to the fact that it can be retrofitted on existing coal power plants. Among the most interesting technologies is the one that employs aqueous ammonia solutions to absorb the generated carbon dioxide. The evaluation of such process...

  9. Evaluation of a target region capture sequencing platform using monogenic diabetes as a study-model

    DEFF Research Database (Denmark)

    Gao, Rui; Liu, Yanxia; Gjesing, Anette Marianne Prior;

    2014-01-01

    Monogenic diabetes is a genetic disease often caused by mutations in genes involved in beta-cell function. Correct sub-categorization of the disease is a prerequisite for appropriate treatment and genetic counseling. Target-region capture sequencing is a combination of genomic region enrichment...

  10. Performance and Modelling of the Pre-combustion Capture Pilot Plant at the Buggenum IGCC

    NARCIS (Netherlands)

    Damen, K.; Faber, R.; Gnutek, R.; Van Dijk, H.A.J.; Trapp, C.; Valenz, L.

    2014-01-01

    This paper summarizes the final results of the pilot plant operation and R&D programme of the CO2 Catch-up project (2008- 2013). The objective of the CO2 Catch-up project is to demonstrate pre-combustion CO2 capture at the pilot plant in Buggenum, the Netherlands, in order to verify the technology p

  11. Fault diagnosis based on continuous simulation models

    Science.gov (United States)

    Feyock, Stefan

    1987-01-01

    The results are described of an investigation of techniques for using continuous simulation models as basis for reasoning about physical systems, with emphasis on the diagnosis of system faults. It is assumed that a continuous simulation model of the properly operating system is available. Malfunctions are diagnosed by posing the question: how can we make the model behave like that. The adjustments that must be made to the model to produce the observed behavior usually provide definitive clues to the nature of the malfunction. A novel application of Dijkstra's weakest precondition predicate transformer is used to derive the preconditions for producing the required model behavior. To minimize the size of the search space, an envisionment generator based on interval mathematics was developed. In addition to its intended application, the ability to generate qualitative state spaces automatically from quantitative simulations proved to be a fruitful avenue of investigation in its own right. Implementations of the Dijkstra transform and the envisionment generator are reproduced in the Appendix.

  12. Modelling and simulation of affinity membrane adsorption.

    Science.gov (United States)

    Boi, Cristiana; Dimartino, Simone; Sarti, Giulio C

    2007-08-24

    A mathematical model for the adsorption of biomolecules on affinity membranes is presented. The model considers convection, diffusion and adsorption kinetics on the membrane module as well as the influence of dead end volumes and lag times; an analysis of flow distribution on the whole system is also included. The parameters used in the simulations were obtained from equilibrium and dynamic experimental data measured for the adsorption of human IgG on A2P-Sartoepoxy affinity membranes. The identification of a bi-Langmuir kinetic mechanisms for the experimental system investigated was paramount for a correct process description and the simulated breakthrough curves were in good agreement with the experimental data. The proposed model provides a new insight into the phenomena involved in the adsorption on affinity membranes and it is a valuable tool to assess the use of membrane adsorbers in large scale processes.

  13. Multiphase reacting flows modelling and simulation

    CERN Document Server

    Marchisio, Daniele L

    2007-01-01

    The papers in this book describe the most widely applicable modeling approaches and are organized in six groups covering from fundamentals to relevant applications. In the first part, some fundamentals of multiphase turbulent reacting flows are covered. In particular the introduction focuses on basic notions of turbulence theory in single-phase and multi-phase systems as well as on the interaction between turbulence and chemistry. In the second part, models for the physical and chemical processes involved are discussed. Among other things, particular emphasis is given to turbulence modeling strategies for multiphase flows based on the kinetic theory for granular flows. Next, the different numerical methods based on Lagrangian and/or Eulerian schemes are presented. In particular the most popular numerical approaches of computational fluid dynamics codes are described (i.e., Direct Numerical Simulation, Large Eddy Simulation, and Reynolds-Averaged Navier-Stokes approach). The book will cover particle-based meth...

  14. Modeling, simulation and optimization of bipedal walking

    CERN Document Server

    Berns, Karsten

    2013-01-01

    The model-based investigation of motions of anthropomorphic systems is an important interdisciplinary research topic involving specialists from many fields such as Robotics, Biomechanics, Physiology, Orthopedics, Psychology, Neurosciences, Sports, Computer Graphics and Applied Mathematics. This book presents a study of basic locomotion forms such as walking and running is of particular interest due to the high demand on dynamic coordination, actuator efficiency and balance control. Mathematical models and numerical simulation and optimization techniques are explained, in combination with experimental data, which can help to better understand the basic underlying mechanisms of these motions and to improve them. Example topics treated in this book are Modeling techniques for anthropomorphic bipedal walking systems Optimized walking motions for different objective functions Identification of objective functions from measurements Simulation and optimization approaches for humanoid robots Biologically inspired con...

  15. A Superbubble Feedback Model for Galaxy Simulations

    CERN Document Server

    Keller, B W; Benincasa, S M; Couchman, H M P

    2014-01-01

    We present a new stellar feedback model that reproduces superbubbles. Superbubbles from clustered young stars evolve quite differently to individual supernovae and are substantially more efficient at generating gas motions. The essential new components of the model are thermal conduction, sub-grid evaporation and a sub-grid multi-phase treatment for cases where the simulation mass resolution is insufficient to model the early stages of the superbubble. The multi-phase stage is short compared to superbubble lifetimes. Thermal conduction physically regulates the hot gas mass without requiring a free parameter. Accurately following the hot component naturally avoids overcooling. Prior approaches tend to heat too much mass, leaving the hot ISM below $10^6$ K and susceptible to rapid cooling unless ad-hoc fixes were used. The hot phase also allows feedback energy to correctly accumulate from multiple, clustered sources, including stellar winds and supernovae. We employ high-resolution simulations of a single star ...

  16. Dynamic Modeling and Simulation of a Commercial Naphtha Catalytic Reforming Process

    Institute of Scientific and Technical Information of China (English)

    胡永有; 徐巍华; 侯卫锋; 苏宏业; 褚健

    2005-01-01

    A first principles-based dynamic model for a continuous catalyst regeneration (CCR) platforming process, the UOP commercial naphtha catalytic reforming process, is developed in this paper. The lumping details of the naphtha feed and reaction scheme of the reaction model are given. The process model is composed of the reforming reaction model with catalyst deactivation, the furnace model and the separator model, which is capable of capturing the major dynamics that occurs in this process system. Dynamic simulations are performed based on Gear numerical algorithm and method of lines (MOL), a numerical technique dealing with partial differential equations (PDEs). The results of simulation are also presented. Dynamic responses caused by disturbances in the process system can be correctly predicted through simulations.

  17. Advancing Material Models for Automotive Forming Simulations

    Science.gov (United States)

    Vegter, H.; An, Y.; ten Horn, C. H. L. J.; Atzema, E. H.; Roelofsen, M. E.

    2005-08-01

    Simulations in automotive industry need more advanced material models to achieve highly reliable forming and springback predictions. Conventional material models implemented in the FEM-simulation models are not capable to describe the plastic material behaviour during monotonic strain paths with sufficient accuracy. Recently, ESI and Corus co-operate on the implementation of an advanced material model in the FEM-code PAMSTAMP 2G. This applies to the strain hardening model, the influence of strain rate, and the description of the yield locus in these models. A subsequent challenge is the description of the material after a change of strain path. The use of advanced high strength steels in the automotive industry requires a description of plastic material behaviour of multiphase steels. The simplest variant is dual phase steel consisting of a ferritic and a martensitic phase. Multiphase materials also contain a bainitic phase in addition to the ferritic and martensitic phase. More physical descriptions of strain hardening than simple fitted Ludwik/Nadai curves are necessary. Methods to predict plastic behaviour of single-phase materials use a simple dislocation interaction model based on the formed cells structures only. At Corus, a new method is proposed to predict plastic behaviour of multiphase materials have to take hard phases into account, which deform less easily. The resulting deformation gradients create geometrically necessary dislocations. Additional micro-structural information such as morphology and size of hard phase particles or grains is necessary to derive the strain hardening models for this type of materials. Measurements available from the Numisheet benchmarks allow these models to be validated. At Corus, additional measured values are available from cross-die tests. This laboratory test can attain critical deformations by large variations in blank size and processing conditions. The tests are a powerful tool in optimising forming simulations

  18. Modelling and simulation of thermal power plants

    Energy Technology Data Exchange (ETDEWEB)

    Eborn, J.

    1998-02-01

    Mathematical modelling and simulation are important tools when dealing with engineering systems that today are becoming increasingly more complex. Integrated production and recycling of materials are trends that give rise to heterogenous systems, which are difficult to handle within one area of expertise. Model libraries are an excellent way to package engineering knowledge of systems and units to be reused by those who are not experts in modelling. Many commercial packages provide good model libraries, but they are usually domain-specific and closed. Heterogenous, multi-domain systems requires open model libraries written in general purpose modelling languages. This thesis describes a model database for thermal power plants written in the object-oriented modelling language OMOLA. The models are based on first principles. Subunits describe volumes with pressure and enthalpy dynamics and flows of heat or different media. The subunits are used to build basic units such as pumps, valves and heat exchangers which can be used to build system models. Several applications are described; a heat recovery steam generator, equipment for juice blending, steam generation in a sulphuric acid plant and a condensing steam plate heat exchanger. Model libraries for industrial use must be validated against measured data. The thesis describes how parameter estimation methods can be used for model validation. Results from a case-study on parameter optimization of a non-linear drum boiler model show how the technique can be used 32 refs, 21 figs

  19. Stratospheric dryness: model simulations and satellite observations

    Directory of Open Access Journals (Sweden)

    J. Lelieveld

    2007-01-01

    Full Text Available The mechanisms responsible for the extreme dryness of the stratosphere have been debated for decades. A key difficulty has been the lack of comprehensive models which are able to reproduce the observations. Here we examine results from the coupled lower-middle atmosphere chemistry general circulation model ECHAM5/MESSy1 together with satellite observations. Our model results match observed temperatures in the tropical lower stratosphere and realistically represent the seasonal and inter-annual variability of water vapor. The model reproduces the very low water vapor mixing ratios (below 2 ppmv periodically observed at the tropical tropopause near 100 hPa, as well as the characteristic tape recorder signal up to about 10 hPa, providing evidence that the dehydration mechanism is well-captured. Our results confirm that the entry of tropospheric air into the tropical stratosphere is forced by large-scale wave dynamics, whereas radiative cooling regionally decelerates upwelling and can even cause downwelling. Thin cirrus forms in the cold air above cumulonimbus clouds, and the associated sedimentation of ice particles between 100 and 200 hPa reduces water mass fluxes by nearly two orders of magnitude compared to air mass fluxes. Transport into the stratosphere is supported by regional net radiative heating, to a large extent in the outer tropics. During summer very deep monsoon convection over Southeast Asia, centered over Tibet, moistens the stratosphere.

  20. Dissolved organic C export is highly dynamic - capturing this variability and challenges in modelling

    Science.gov (United States)

    Waldron, S.; Coleman, M.; Scott, E. M.; Drew, S.

    2013-12-01

    High resolution, field-deployable sensors offer opportunities to deepen our understanding of natural environmental systems, and measure the ';riverine pulse'. Studies utilising high-resolution equipment have demonstrated that sampling hydrological variables on traditional low frequency rates (such as once a week) creates a simplified picture of conditions that does not capture a true reflection of how fluvial systems operate. Dissolved organic carbon (DOC) represents a large and diverse mixture of compounds (including sugars, amino acids and humic substances) and concentration and composition of this pool varies globally. Understanding transport of this C pool in fluvial systems is important as it 1) represents the lateral export of C no longer sequestered in the terrestrial system, 2) surface water concentrations have been observed to have increased globally and we need to know if this trend is continuing and 3) when water is abstracted the purification processes removing DOC from the water, can create harmful by-products and so prior knowledge of inflow loading is valuable. Traditionally [DOC] has been measured using manual sampling methods, where a water sample would be collected in the field and returned to the lab. This approach can provide reliable data but the resource required to sustain this make it nearly impossible to measure the ';riverine pulse' through the information in long and detailed time series. In recent years new technology designed to estimate [DOC] in-situ has been developed. We have used one of these devices, which measures absorption in both the visible and UV wavelength regions of the electromagnetic spectrum and from this absorbance profile an algorithm estimates [DOC]. We have deployed this system in the field environment and after overcoming initial challenges have an almost continuous time series of [DOC], measured at 30 minute intervals, since May 2012. The logger has been functioning over a temperature range of 0.5 - 23 °C and a