Coastal Surveillance Baseline Model Development
2015-02-27
that were considered too numerous for inclusion in this report. Therefore, the Access was reconfigured to cover only the first two weeks of...radar (SAR). One can also define jammers and detailed antenna models, as well as a variety of effects associated with specific types of atmospheric...line loss and temperature, antenna noise) to help simulate real-world RF situations more accurately if necessary. C.1.2 Radar Cross-Section Property
Geochemical modelling baseline compositions of groundwater
DEFF Research Database (Denmark)
Postma, Diederik Jan; Kjøller, Claus; Andersen, Martin Søgaard
2008-01-01
Reactive transport models, were developed to explore the evolution in groundwater chemistry along the flow path in three aquifers; the Triassic East Midland aquifer (UK), the Miocene aquifer at Valreas (F) and the Cretaceous aquifer near Aveiro (P). All three aquifers contain very old groundwaters...... of the evolution in natural baseline properties in groundwater....
Baseline and benchmark model development for hotels
Hooks, Edward T., Jr.
The hotel industry currently faces rising energy costs and requires the tools to maximize energy efficiency. In order to achieve this goal a clear definition of the current methods used to measure and monitor energy consumption is made. Uncovering the limitations to the most common practiced analysis strategies and presenting methods that can potentially overcome those limitations is the main purpose. Techniques presented can be used for measurement and verification of energy efficiency plans and retrofits. Also, modern energy modeling tool are introduced to demonstrate how they can be utilized for benchmarking and baseline models. This will provide the ability to obtain energy saving recommendations and parametric analysis to explore energy savings potential. These same energy models can be used in design decisions for new construction. An energy model is created of a resort style hotel that over one million square feet and has over one thousand rooms. A simulation and detailed analysis is performed on a hotel room. The planning process for creating the model and acquiring data from the hotel room to calibrate and verify the simulation will be explained. An explanation as to how this type of modeling can potentially be beneficial for future baseline and benchmarking strategies for the hotel industry. Ultimately the conclusion will address some common obstacles the hotel industry has in reaching their full potential of energy efficiency and how these techniques can best serve them.
The WITCH Model. Structure, Baseline, Solutions.
Energy Technology Data Exchange (ETDEWEB)
Bosetti, V.; Massetti, E.; Tavoni, M.
2007-07-01
WITCH - World Induced Technical Change Hybrid - is a regionally disaggregated hard link hybrid global model with a neoclassical optimal growth structure (top down) and an energy input detail (bottom up). The model endogenously accounts for technological change, both through learning curves affecting prices of new vintages of capital and through R and D investments. The model features the main economic and environmental policies in each world region as the outcome of a dynamic game. WITCH belongs to the class of Integrated Assessment Models as it possesses a climate module that feeds climate changes back into the economy. In this paper we provide a thorough discussion of the model structure and baseline projections. We report detailed information on the evolution of energy demand, technology and CO2 emissions. Finally, we explicitly quantifiy the role of free riding in determining the emissions scenarios. (auth)
Geochemical modelling baseline compositions of groundwater
DEFF Research Database (Denmark)
Postma, Diederik Jan; Kjøller, Claus; Andersen, Martin Søgaard;
2008-01-01
and variations in water chemistry that are caused by large scale geochemical processes taking place at the timescale of thousands of years. The most important geochemical processes are ion exchange (Valreas and Aveiro) where freshwater solutes are displacing marine ions from the sediment surface, and carbonate...... dissolution (East Midlands, Valreas and Aveiro). Reactive transport models, employing the code PHREEQC, which included these geochemical processes and one-dimensional solute transport were able to duplicate the observed patterns in water quality. These models may provide a quantitative understanding...
Annual Technology Baseline (Including Supporting Data); NREL (National Renewable Energy Laboratory)
Energy Technology Data Exchange (ETDEWEB)
Blair, Nate; Cory, Karlynn; Hand, Maureen; Parkhill, Linda; Speer, Bethany; Stehly, Tyler; Feldman, David; Lantz, Eric; Augusting, Chad; Turchi, Craig; O' Connor, Patrick
2015-07-08
Consistent cost and performance data for various electricity generation technologies can be difficult to find and may change frequently for certain technologies. With the Annual Technology Baseline (ATB), National Renewable Energy Laboratory provides an organized and centralized dataset that was reviewed by internal and external experts. It uses the best information from the Department of Energy laboratory's renewable energy analysts and Energy Information Administration information for conventional technologies. The ATB will be updated annually in order to provide an up-to-date repository of current and future cost and performance data. Going forward, we plan to revise and refine the values using best available information. The ATB includes both a presentation with notes (PDF) and an associated Excel Workbook. The ATB includes the following electricity generation technologies: land-based wind; offshore wind; utility-scale solar PV; concentrating solar power; geothermal power; hydropower plants (upgrades to existing facilities, powering non-powered dams, and new stream-reach development); conventional coal; coal with carbon capture and sequestration; integrated gasification combined cycle coal; natural gas combustion turbines; natural gas combined cycle; conventional biopower. Nuclear laboratory's renewable energy analysts and Energy Information Administration information for conventional technologies. The ATB will be updated annually in order to provide an up-to-date repository of current and future cost and performance data. Going forward, we plan to revise and refine the values using best available information.
Including Magnetostriction in Micromagnetic Models
Conbhuí, Pádraig Ó.; Williams, Wyn; Fabian, Karl; Nagy, Lesleis
2016-04-01
The magnetic anomalies that identify crustal spreading are predominantly recorded by basalts formed at the mid-ocean ridges, whose magnetic signals are dominated by iron-titanium-oxides (Fe3-xTixO4), so called "titanomagnetites", of which the Fe2.4Ti0.6O4 (TM60) phase is the most common. With sufficient quantities of titanium present, these minerals exhibit strong magnetostriction. To date, models of these grains in the pseudo-single domain (PSD) range have failed to accurately account for this effect. In particular, a popular analytic treatment provided by Kittel (1949) for describing the magnetostrictive energy as an effective increase of the anisotropy constant can produce unphysical strains for non-uniform magnetizations. I will present a rigorous approach based on work by Brown (1966) and by Kroner (1958) for including magnetostriction in micromagnetic codes which is suitable for modelling hysteresis loops and finding remanent states in the PSD regime. Preliminary results suggest the more rigorously defined micromagnetic models exhibit higher coercivities and extended single domain ranges when compared to more simplistic approaches.
[Baseline clinical characteristics and management of patients included in IBERICAN study].
Barrios, V; Escobar, C; Llisterri, J L; Rodríguez Roca, G; Badimón, J J; Vergara, J; Prieto, M Á; Serrano, A; Cinza, S; Murillo, C
2015-01-01
To determine the prevalence and incidence of cardiovascular risk factors and cardiovascular events in Spain, as well as the quality of the follow-up in clinical practice. In this study the baseline data of the first interim analysis of IBERICAN are shown (n=830). IBERICAN is a multicenter, longitudinal and observational population-based study of patients daily attended in primary care setting according to clinical practice in Spain. Subjects between 18 and 85 years daily attended in primary care setting are being included consecutively. Treatment of patients will be performed according only to clinical criteria of investigators. Blood pressure control was defined according to 2013 European guidelines of hypertension; LDL-cholesterol control was defined according to 2012 European guidelines of cardiovascular prevention; diabetes control was defined as HbA1ccardiovascular risk factors with a poor control. Copyright © 2014 Sociedad Española de Médicos de Atención Primaria (SEMERGEN). Publicado por Elsevier España. All rights reserved.
Model Order Selection in Multi-baseline Interferometric Radar Systems
Directory of Open Access Journals (Sweden)
Fulvio Gini
2005-12-01
Full Text Available Synthetic aperture radar interferometry (InSAR is a powerful technique to derive three-dimensional terrain images. Interest is growing in exploiting the advanced multi-baseline mode of InSAR to solve layover effects from complex orography, which generate reception of unexpected multicomponent signals that degrade imagery of both terrain radar reflectivity and height. This work addresses a few problems related to the implementation into interferometric processing of nonlinear algorithms for estimating the number of signal components, including a system trade-off analysis. Performance of various eigenvalues-based information-theoretic criteria (ITC algorithms is numerically investigated under some realistic conditions. In particular, speckle effects from surface and volume scattering are taken into account as multiplicative noise in the signal model. Robustness to leakage of signal power into the noise eigenvalues and operation with a small number of looks are investigated. The issue of baseline optimization for detection is also addressed. The use of diagonally loaded ITC methods is then proposed as a tool for robust operation in the presence of speckle decorrelation. Finally, case studies of a nonuniform array are studied and recommendations for a proper combination of ITC methods and system configuration are given.
Functional Testing Protocols for Commercial Building Efficiency Baseline Modeling Software
Energy Technology Data Exchange (ETDEWEB)
Jump, David; Price, Phillip N.; Granderson, Jessica; Sohn, Michael
2013-09-06
This document describes procedures for testing and validating proprietary baseline energy modeling software accuracy in predicting energy use over the period of interest, such as a month or a year. The procedures are designed according to the methodology used for public domain baselining software in another LBNL report that was (like the present report) prepared for Pacific Gas and Electric Company: ?Commercial Building Energy Baseline Modeling Software: Performance Metrics and Method Testing with Open Source Models and Implications for Proprietary Software Testing Protocols? (referred to here as the ?Model Analysis Report?). The test procedure focuses on the quality of the software?s predictions rather than on the specific algorithms used to predict energy use. In this way the software vendor is not required to divulge or share proprietary information about how their software works, while enabling stakeholders to assess its performance.
Preclinical models for neuroblastoma: establishing a baseline for treatment.
Directory of Open Access Journals (Sweden)
Tal Teitz
Full Text Available BACKGROUND: Preclinical models of pediatric cancers are essential for testing new chemotherapeutic combinations for clinical trials. The most widely used genetic model for preclinical testing of neuroblastoma is the TH-MYCN mouse. This neuroblastoma-prone mouse recapitulates many of the features of human neuroblastoma. Limitations of this model include the low frequency of bone marrow metastasis, the lack of information on whether the gene expression patterns in this system parallels human neuroblastomas, the relatively slow rate of tumor formation and variability in tumor penetrance on different genetic backgrounds. As an alternative, preclinical studies are frequently performed using human cell lines xenografted into immunocompromised mice, either as flank implant or orthtotopically. Drawbacks of this system include the use of cell lines that have been in culture for years, the inappropriate microenvironment of the flank or difficult, time consuming surgery for orthotopic transplants and the absence of an intact immune system. PRINCIPAL FINDINGS: Here we characterize and optimize both systems to increase their utility for preclinical studies. We show that TH-MYCN mice develop tumors in the paraspinal ganglia, but not in the adrenal, with cellular and gene expression patterns similar to human NB. In addition, we present a new ultrasound guided, minimally invasive orthotopic xenograft method. This injection technique is rapid, provides accurate targeting of the injected cells and leads to efficient engraftment. We also demonstrate that tumors can be detected, monitored and quantified prior to visualization using ultrasound, MRI and bioluminescence. Finally we develop and test a "standard of care" chemotherapy regimen. This protocol, which is based on current treatments for neuroblastoma, provides a baseline for comparison of new therapeutic agents. SIGNIFICANCE: The studies suggest that use of both the TH-NMYC model of neuroblastoma and the
Project W-320 thermal hydraulic model benchmarking and baselining
Energy Technology Data Exchange (ETDEWEB)
Sathyanarayana, K.
1998-09-28
Project W-320 will be retrieving waste from Tank 241-C-106 and transferring the waste to Tank 241-AY-102. Waste in both tanks must be maintained below applicable thermal limits during and following the waste transfer. Thermal hydraulic process control models will be used for process control of the thermal limits. This report documents the process control models and presents a benchmarking of the models with data from Tanks 241-C-106 and 241-AY-102. Revision 1 of this report will provide a baselining of the models in preparation for the initiation of sluicing.
DEVELOPMENT OF WATER CIRCULATION MODEL INCLUDING IRRIGATION
Kotsuki, Shunji; Tanaka, Kenji; Kojiri, Toshiharu; Hamaguchi, Toshio
It is well known that since agricultural water withdrawal has much affect on water circulation system, accurate analysis of river discharge or water balance are difficult with less regard for it. In this study, water circulation model composed of land surface model and distributed runoff model is proposed at 10km 10km resolution. In this model, irrigation water, which is estimated with land surface model, is introduced to river discharge analysis. The model is applied to the Chao Phraya River in Thailand, and reproduced seasonal water balance. Additionally, the discharge on dry season simulated with the model is improved as a result of including irrigation. Since the model, which is basically developed from global data sets, simulated seasonal change of river discharge, it can be suggested that our model has university to other river basins.
1973-01-01
The traffic analyses and system requirements data generated in the study resulted in the development of two traffic models; the baseline traffic model and the new traffic model. The baseline traffic model provides traceability between the numbers and types of geosynchronous missions considered in the study and the entire spectrum of missions foreseen in the total national space program. The information presented pertaining to the baseline traffic model includes: (1) definition of the baseline traffic model, including identification of specific geosynchronous missions and their payload delivery schedules through 1990; (2) Satellite location criteria, including the resulting distribution of the satellite population; (3) Geosynchronous orbit saturation analyses, including the effects of satellite physical proximity and potential electromagnetic interference; and (4) Platform system requirements analyses, including satellite and mission equipment descriptions, the options and limitations in grouping satellites, and on-orbit servicing criteria (both remotely controlled and man-attended).
Gómez-Marcos, Manuel A; Agudo-Conde, Cristina; Torcal, Jesús; Echevarria, Pilar; Domingo, Mar; Arietaleanizbeascoa, María; Sanz-Guinea, Aitor; de la Torre, Maria M; Ramírez, Jose I; García-Ortiz, Luis
2016-03-01
To describe the baseline date and drugs therapy changes during treatment optimization in patients with heart failure with depressed systolic function included in the EFICAR study. Multicenter randomized clinical trial. Seven Health Centers. 150 patients (ICFSD) age 68±10 years, 77% male. Sociodemographic variables, comorbidities (Charlson index), functional capacity and quality of life. Drug therapy optimization was performed. The main etiology was ischemic heart disease (45%), with 89% in functional class II. The Charlson index was 2.03±1.05. The ejection fraction mean was 37%±8, 19% with ejection fraction <30%. With the stress test 6.3±1.6 mean was reached, with the 6 minutes test 446±78 meters and the chair test 13.7±4.4 seconds. The overall quality of life with ejection fraction was 22.8±18.7 and with the Short Form-36 Health Survey, physical health 43.3±8.4 and mental health 50.1±10.6. After optimizing the treatment, the percentage of patients on drugs therapy and the dose of angiotensin converting enzyme inhibitors, angiotensin II receptor antagonists and beta-blockers were not changed. The majority of the subjects are in functional class II, with functional capacity and quality of life decreased and comorbidity index high. A protocolized drug therapy adjustment did not increase the dose or number of patients with effective drugs for heart failure with depressed systolic function. Copyright © 2015 Elsevier España, S.L.U. All rights reserved.
Models of bovine babesiosis including juvenile cattle.
Saad-Roy, C M; Shuai, Zhisheng; van den Driessche, P
2015-03-01
Bovine Babesiosis in cattle is caused by the transmission of protozoa of Babesia spp. by ticks as vectors. Juvenile cattle (Babesiosis, rarely show symptoms, and acquire immunity upon recovery. Susceptibility to the disease varies between breeds of cattle. Models of the dynamics of Bovine Babesiosis transmitted by the cattle tick that include these factors are formulated as systems of ordinary differential equations. Basic reproduction numbers are calculated, and it is proved that if these numbers are below the threshold value of one, then Bovine Babesiosis dies out. However, above the threshold number of one, the disease may approach an endemic state. In this case, control measures are suggested by determining target reproduction numbers. The percentage of a particular population (for example, the adult bovine population) needed to be controlled to eradicate the disease is evaluated numerically using Columbia data from the literature.
DEFF Research Database (Denmark)
Bruze, Magnus; Andersen, Klaus Ejner; Goossens, An
2008-01-01
various European centres when tested in consecutive dermatitis patients. CONCLUSIONS: From 2008, pet. preparations of fragrance mix 2 at 14% w/w (5.6 mg/cm(2)) and hydroxyisohexyl 3-cyclohexene carboxaldehyde at 5% w/w (2.0 mg/cm(2)) are recommended for inclusion in the baseline series. With the Finn...... Chamber technique, a dose of 20 mg pet. preparation is recommended. Whenever there is a positive reaction to fragrance mix 2, additional patch testing with the 6 ingredients, 5 if there are simultaneous positive reactions to hydroxyisohexyl 3-cyclohexene carboxaldehyde and fragrance mix 2, is recommended....
Energy Technology Data Exchange (ETDEWEB)
Sacks, R.A.; Williams, W.W.; Henesian, M.A.; Orth, C.D.; Haney, S.W.; Trenholme, J.B.; Auerbach, J.M.; Lawson, J.K.
1997-02-25
The performance of the NIF baseline design has been modeled in two transverse dimensions using the Fourier optics code PROP92 and the nonlinear harmonic conversion code THG4DO1. The results obtained are in good agreement with those of the ID versions of these codes which were used during the design optimization, yielding good confidence that a near- optimal design has been chosen. We project that this design is able to fulfill NIF`s three major mission specifications without component damage. Further modeling, including the effects of air- path turbulence, quasi-static thermal deformations, SSD, and sensitivity to misalignment and component tolerances is ongoing.
An Integrated Biochemistry Laboratory, Including Molecular Modeling
Hall, Adele J. Wolfson Mona L.; Branham, Thomas R.
1996-11-01
) experience with methods of protein purification; (iii) incorporation of appropriate controls into experiments; (iv) use of basic statistics in data analysis; (v) writing papers and grant proposals in accepted scientific style; (vi) peer review; (vii) oral presentation of results and proposals; and (viii) introduction to molecular modeling. Figure 1 illustrates the modular nature of the lab curriculum. Elements from each of the exercises can be separated and treated as stand-alone exercises, or combined into short or long projects. We have been able to offer the opportunity to use sophisticated molecular modeling in the final module through funding from an NSF-ILI grant. However, many of the benefits of the research proposal can be achieved with other computer programs, or even by literature survey alone. Figure 1.Design of project-based biochemistry laboratory. Modules (projects, or portions of projects) are indicated as boxes. Each of these can be treated independently, or used as part of a larger project. Solid lines indicate some suggested paths from one module to the next. The skills and knowledge required for protein purification and design are developed in three units: (i) an introduction to critical assays needed to monitor degree of purification, including an evaluation of assay parameters; (ii) partial purification by ion-exchange techniques; and (iii) preparation of a grant proposal on protein design by mutagenesis. Brief descriptions of each of these units follow, with experimental details of each project at the end of this paper. Assays for Lysozyme Activity and Protein Concentration (4 weeks) The assays mastered during the first unit are a necessary tool for determining the purity of the enzyme during the second unit on purification by ion exchange. These assays allow an introduction to the concept of specific activity (units of enzyme activity per milligram of total protein) as a measure of purity. In this first sequence, students learn a turbidimetric assay
Seepage Model for PA Including Dift Collapse
Energy Technology Data Exchange (ETDEWEB)
G. Li; C. Tsang
2000-12-20
The purpose of this Analysis/Model Report (AMR) is to document the predictions and analysis performed using the Seepage Model for Performance Assessment (PA) and the Disturbed Drift Seepage Submodel for both the Topopah Spring middle nonlithophysal and lower lithophysal lithostratigraphic units at Yucca Mountain. These results will be used by PA to develop the probability distribution of water seepage into waste-emplacement drifts at Yucca Mountain, Nevada, as part of the evaluation of the long term performance of the potential repository. This AMR is in accordance with the ''Technical Work Plan for Unsaturated Zone (UZ) Flow and Transport Process Model Report'' (CRWMS M&O 2000 [153447]). This purpose is accomplished by performing numerical simulations with stochastic representations of hydrological properties, using the Seepage Model for PA, and evaluating the effects of an alternative drift geometry representing a partially collapsed drift using the Disturbed Drift Seepage Submodel. Seepage of water into waste-emplacement drifts is considered one of the principal factors having the greatest impact of long-term safety of the repository system (CRWMS M&O 2000 [153225], Table 4-1). This AMR supports the analysis and simulation that are used by PA to develop the probability distribution of water seepage into drift, and is therefore a model of primary (Level 1) importance (AP-3.15Q, ''Managing Technical Product Inputs''). The intended purpose of the Seepage Model for PA is to support: (1) PA; (2) Abstraction of Drift-Scale Seepage; and (3) Unsaturated Zone (UZ) Flow and Transport Process Model Report (PMR). Seepage into drifts is evaluated by applying numerical models with stochastic representations of hydrological properties and performing flow simulations with multiple realizations of the permeability field around the drift. The Seepage Model for PA uses the distribution of permeabilities derived from air injection testing in
Enhanced battery model including temperature effects
Rosca, B.; Wilkins, S.
2013-01-01
Within electric and hybrid vehicles, batteries are used to provide/buffer the energy required for driving. However, battery performance varies throughout the temperature range specific to automotive applications, and as such, models that describe this behaviour are required. This paper presents a dy
Enhanced battery model including temperature effects
Rosca, B.; Wilkins, S.
2013-01-01
Within electric and hybrid vehicles, batteries are used to provide/buffer the energy required for driving. However, battery performance varies throughout the temperature range specific to automotive applications, and as such, models that describe this behaviour are required. This paper presents a dy
Enhanced battery model including temperature effects
Rosca, B.; Wilkins, S.
2013-01-01
Within electric and hybrid vehicles, batteries are used to provide/buffer the energy required for driving. However, battery performance varies throughout the temperature range specific to automotive applications, and as such, models that describe this behaviour are required. This paper presents a
Baseline Assessment of TREAT for Modeling and Analysis Needs
Energy Technology Data Exchange (ETDEWEB)
Bess, John Darrell [Idaho National Lab. (INL), Idaho Falls, ID (United States); DeHart, Mark David [Idaho National Lab. (INL), Idaho Falls, ID (United States)
2015-10-01
TREAT is an air-cooled, graphite moderated, thermal, heterogeneous test facility designed to evaluate reactor fuels and structural materials under conditions simulating various types of nuclear excursions and transient undercooling situations that could occur in a nuclear reactor. After 21 years in a standby mode, TREAT is being re-activated to revive transient testing capabilities. Given the time elapsed and the concurrent loss of operating experience, current generation and advanced computational methods are being applied to begin TREAT modeling and simulation prior to renewed at-power operations. Such methods have limited value in predicting the behavior of TREAT without proper validation. Hence, the U.S. DOE has developed a number of programs to support development of benchmarks for both critical and transient operations. Extensive effort has been expended at INL to collect detailed descriptions, drawings and specifications for all aspects of TREAT, and to resolve conflicting data found through this process. This report provides a collection of these data, with updated figures that are significantly more readable than historic drawings and illustrations, compositions, and dimensions based on the best available sources. This document is not nor should it be considered to be a benchmark report. Rather, it is intended to provide one-stop shopping, to the extent possible, for other work that seeks to prepare detailed, accurate models of the core and its components. Given the nature of the variety of historic documents available and the loss of institutional memory, the only completely accurate database of TREAT data is TREAT itself. Unfortunately, disassembly of TREAT for inspection, assay, and measurement is highly unlikely. Hence the data provided herein is intended serve as a best-estimate substitute.
Modeling nonlinear errors in surface electromyography due to baseline noise: a new methodology.
Law, Laura Frey; Krishnan, Chandramouli; Avin, Keith
2011-01-01
The surface electromyographic (EMG) signal is often contaminated by some degree of baseline noise. It is customary for scientists to subtract baseline noise from the measured EMG signal prior to further analyses based on the assumption that baseline noise adds linearly to the observed EMG signal. The stochastic nature of both the baseline and EMG signal, however, may invalidate this assumption. Alternately, "true" EMG signals may be either minimally or nonlinearly affected by baseline noise. This information is particularly relevant at low contraction intensities when signal-to-noise ratios (SNR) may be lowest. Thus, the purpose of this simulation study was to investigate the influence of varying levels of baseline noise (approximately 2-40% maximum EMG amplitude) on mean EMG burst amplitude and to assess the best means to account for signal noise. The simulations indicated baseline noise had minimal effects on mean EMG activity for maximum contractions, but increased nonlinearly with increasing noise levels and decreasing signal amplitudes. Thus, the simple baseline noise subtraction resulted in substantial error when estimating mean activity during low intensity EMG bursts. Conversely, correcting EMG signal as a nonlinear function of both baseline and measured signal amplitude provided highly accurate estimates of EMG amplitude. This novel nonlinear error modeling approach has potential implications for EMG signal processing, particularly when assessing co-activation of antagonist muscles or small amplitude contractions where the SNR can be low.
Statistical Analysis of Baseline Load Models for Non-Residential Buildings
Energy Technology Data Exchange (ETDEWEB)
Coughlin, Katie; Piette, Mary Ann; Goldman, Charles; Kiliccote, Sila
2008-11-10
Policymakers are encouraging the development of standardized and consistent methods to quantify the electric load impacts of demand response programs. For load impacts, an essential part of the analysis is the estimation of the baseline load profile. In this paper, we present a statistical evaluation of the performance of several different models used to calculate baselines for commercial buildings participating in a demand response program in California. In our approach, we use the model to estimate baseline loads for a large set of proxy event days for which the actual load data are also available. Measures of the accuracy and bias of different models, the importance of weather effects, and the effect of applying morning adjustment factors (which use data from the day of the event to adjust the estimated baseline) are presented. Our results suggest that (1) the accuracy of baseline load models can be improved substantially by applying a morning adjustment, (2) the characterization of building loads by variability and weather sensitivity is a useful indicator of which types of baseline models will perform well, and (3) models that incorporate temperature either improve the accuracy of the model fit or do not change it.
Predictive modeling of respiratory tumor motion for real-time prediction of baseline shifts
Balasubramanian, A.; Shamsuddin, R.; Prabhakaran, B.; Sawant, A.
2017-03-01
Baseline shifts in respiratory patterns can result in significant spatiotemporal changes in patient anatomy (compared to that captured during simulation), in turn, causing geometric and dosimetric errors in the administration of thoracic and abdominal radiotherapy. We propose predictive modeling of the tumor motion trajectories for predicting a baseline shift ahead of its occurrence. The key idea is to use the features of the tumor motion trajectory over a 1 min window, and predict the occurrence of a baseline shift in the 5 s that immediately follow (lookahead window). In this study, we explored a preliminary trend-based analysis with multi-class annotations as well as a more focused binary classification analysis. In both analyses, a number of different inter-fraction and intra-fraction training strategies were studied, both offline as well as online, along with data sufficiency and skew compensation for class imbalances. The performance of different training strategies were compared across multiple machine learning classification algorithms, including nearest neighbor, Naïve Bayes, linear discriminant and ensemble Adaboost. The prediction performance is evaluated using metrics such as accuracy, precision, recall and the area under the curve (AUC) for repeater operating characteristics curve. The key results of the trend-based analysis indicate that (i) intra-fraction training strategies achieve highest prediction accuracies (90.5-91.4%) (ii) the predictive modeling yields lowest accuracies (50-60%) when the training data does not include any information from the test patient; (iii) the prediction latencies are as low as a few hundred milliseconds, and thus conducive for real-time prediction. The binary classification performance is promising, indicated by high AUCs (0.96-0.98). It also confirms the utility of prior data from previous patients, and also the necessity of training the classifier on some initial data from the new patient for reasonable
Energy Technology Data Exchange (ETDEWEB)
University of California, Berkeley; Addy, Nathan; Kiliccote, Sila; Mathieu, Johanna; Callaway, Duncan S.
2012-06-13
Accurate evaluation of the performance of buildings participating in Demand Response (DR) programs is critical to the adoption and improvement of these programs. Typically, we calculate load sheds during DR events by comparing observed electric demand against counterfactual predictions made using statistical baseline models. Many baseline models exist and these models can produce different shed calculations. Moreover, modelers implementing the same baseline model can make different modeling implementation choices, which may affect shed estimates. In this work, using real data, we analyze the effect of different modeling implementation choices on shed predictions. We focused on five issues: weather data source, resolution of data, methods for determining when buildings are occupied, methods for aligning building data with temperature data, and methods for power outage filtering. Results indicate sensitivity to the weather data source and data filtration methods as well as an immediate potential for automation of methods to choose building occupied modes.
Error Modeling and Analysis for InSAR Spatial Baseline Determination of Satellite Formation Flying
Directory of Open Access Journals (Sweden)
Jia Tu
2012-01-01
Full Text Available Spatial baseline determination is a key technology for interferometric synthetic aperture radar (InSAR missions. Based on the intersatellite baseline measurement using dual-frequency GPS, errors induced by InSAR spatial baseline measurement are studied in detail. The classifications and characters of errors are analyzed, and models for errors are set up. The simulations of single factor and total error sources are selected to evaluate the impacts of errors on spatial baseline measurement. Single factor simulations are used to analyze the impact of the error of a single type, while total error sources simulations are used to analyze the impacts of error sources induced by GPS measurement, baseline transformation, and the entire spatial baseline measurement, respectively. Simulation results show that errors related to GPS measurement are the main error sources for the spatial baseline determination, and carrier phase noise of GPS observation and fixing error of GPS receiver antenna are main factors of errors related to GPS measurement. In addition, according to the error values listed in this paper, 1 mm level InSAR spatial baseline determination should be realized.
Evaluation of the Predictive Accuracy of Five Whole Building Baseline Models
Energy Technology Data Exchange (ETDEWEB)
Granderson, Jessica [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Price, Phillip [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States)
2012-08-31
This report documents the relative and absolute performance of five baseline models used to characterize wholebuilding energy consumption. The Pulse Adaptive Model1, multi-parameter change-point, mean-week, day-time-emperature, and LBNL models were evaluated according to a number of statistical ‘goodness of fit’ metrics, to determine their accuracy in characterizing the energy consumption of a set of 29 buildings. The baseline training period, prediction horizon, and predicted energy quantity (daily, weekly, and monthly energy consumption) were varied, and model predictions were compared to interval meter data to determine the accuracy of each model. Three combinations of baseline training periods and prediction horizons were considered: 6 months of training to generate a 12-month prediction; 9 months of training to generate a 7-month prediction; and 12 months of training to generate a 6- month prediction.
A baseline-free procedure for transformation models under interval censorship.
Gu, Ming Gao; Sun, Liuquan; Zuo, Guoxin
2005-12-01
An important property of Cox regression model is that the estimation of regression parameters using the partial likelihood procedure does not depend on its baseline survival function. We call such a procedure baseline-free. Using marginal likelihood, we show that an baseline-free procedure can be derived for a class of general transformation models under interval censoring framework. The baseline-free procedure results a simplified and stable computation algorithm for some complicated and important semiparametric models, such as frailty models and heteroscedastic hazard/rank regression models, where the estimation procedures so far available involve estimation of the infinite dimensional baseline function. A detailed computational algorithm using Markov Chain Monte Carlo stochastic approximation is presented. The proposed procedure is demonstrated through extensive simulation studies, showing the validity of asymptotic consistency and normality. We also illustrate the procedure with a real data set from a study of breast cancer. A heuristic argument showing that the score function is a mean zero martingale is provided.
Modelling acute oral mammalian toxicity. 1. Definition of a quantifiable baseline effect.
Koleva, Yana K; Cronin, Mark T D; Madden, Judith C; Schwöbel, Johannes A H
2011-10-01
Quantitative structure-activity relationships (QSARs) provide a useful tool to define a relationship between chemical structure and toxicity and allow for the prediction of the toxicity of untested chemicals. QSAR models based upon an anaesthetic or narcosis mechanism represent a baseline, or minimum, toxicity, i.e. unless a chemical acts by another, more specific, mechanism, its toxicity will be predicted by such models. The aim of this investigation was to develop baseline models for the acute toxicity of chemicals to mammals (rat and mouse) following the oral route of administration. The availability of such baseline toxicity models for mammalian species can provide a probe for testing new chemicals with respect to their molecular mechanism of toxicity. Multiple-regression type structure-toxicity relationships were derived . (i.e., from oral log LD(50)(-1) data for mammalian species (rat and mouse) and the 1-octanol/water partition coefficient (log P) of classic non-polar narcotics). Subsequently, these models were used to distinguish between reactive chemicals of different mechanistic domains and baseline toxic chemicals. Comparison of measured toxicity data for oral rat and mouse LD(50) with predictions from baseline QSAR provides a means of identifying mechanistic categories and for categorising more specific acute mechanisms. Copyright © 2011 Elsevier Ltd. All rights reserved.
Hu, Chuanpu; Xu, Zhenhua; Mendelsohn, Alan M; Zhou, Honghui
2013-02-01
Accurate exposure-response modeling is important in drug development. Methods are still evolving in the use of mechanistic, e.g., indirect response (IDR) models to relate discrete endpoints, mostly of the ordered categorical form, to placebo/co-medication effect and drug exposure. When the discrete endpoint is derived using change-from-baseline measurements, a mechanistic exposure-response modeling approach requires adjustment to maintain appropriate interpretation. This manuscript describes a new modeling method that integrates a latent-variable representation of IDR models with standard logistic regression. The new method also extends to general link functions that cover probit regression or continuous clinical endpoint modeling. Compared to an earlier latent variable approach that constrained the baseline probability of response to be 0, placebo effect parameters in the new model formulation are more readily interpretable and can be separately estimated from placebo data, thus allowing convenient and robust model estimation. A general inherent connection of some latent variable representations with baseline-normalized standard IDR models is derived. For describing clinical response endpoints, Type I and Type III IDR models are shown to be equivalent, therefore there are only three identifiable IDR models. This approach was applied to data from two phase III clinical trials of intravenously administered golimumab for the treatment of rheumatoid arthritis, where 20, 50, and 70% improvement in the American College of Rheumatology disease severity criteria were used as efficacy endpoints. Likelihood profiling and visual predictive checks showed reasonable parameter estimation precision and model performance.
Directory of Open Access Journals (Sweden)
Peter Bacopoulos
2014-03-01
Full Text Available Anecdotal data are currently the best data available to describe baseline conditions of beached oil tar balls on Florida’s First Coast beaches. This study combines field methods and numerical modeling to define a data-driven knowledge base of oil tar ball baseline conditions. Outcomes from the field study include an established methodology for field data collection and laboratory testing of beached oil tar balls, spatial maps of collected samples and analysis of the data as to transport/wash-up trends. Archives of the electronic data, including GPS locations and other informational tags, and collected samples are presented, as are the physical and chemical analyses of the collected samples. The thrust of the physical and chemical analyses is to differentiate the collected samples into highly suspect oil tar balls versus false/non-oil tar ball samples. The numerical modeling involves two-dimensional hydrodynamic simulations of astronomic tides. Results from the numerical modeling include velocity residuals that show ebb-dominated residual currents exiting the inlet via an offshore, counter-rotating dual-eddy system. The tidally derived residual currents are used as one explanation for the observed transport trends. The study concludes that the port activity in the St. Johns River is not majorly contributing to the baseline conditions of oil tar ball wash-up on Florida’s First Coast beaches.
Bayesian inference of baseline fertility and treatment effects via a crop yield-fertility model.
Directory of Open Access Journals (Sweden)
Hungyen Chen
Full Text Available To effectively manage soil fertility, knowledge is needed of how a crop uses nutrients from fertilizer applied to the soil. Soil quality is a combination of biological, chemical and physical properties and is hard to assess directly because of collective and multiple functional effects. In this paper, we focus on the application of these concepts to agriculture. We define the baseline fertility of soil as the level of fertility that a crop can acquire for growth from the soil. With this strict definition, we propose a new crop yield-fertility model that enables quantification of the process of improving baseline fertility and the effects of treatments solely from the time series of crop yields. The model was modified from Michaelis-Menten kinetics and measured the additional effects of the treatments given the baseline fertility. Using more than 30 years of experimental data, we used the Bayesian framework to estimate the improvements in baseline fertility and the effects of fertilizer and farmyard manure (FYM on maize (Zea mays, barley (Hordeum vulgare, and soybean (Glycine max yields. Fertilizer contributed the most to the barley yield and FYM contributed the most to the soybean yield among the three crops. The baseline fertility of the subsurface soil was very low for maize and barley prior to fertilization. In contrast, the baseline fertility in this soil approximated half-saturated fertility for the soybean crop. The long-term soil fertility was increased by adding FYM, but the effect of FYM addition was reduced by the addition of fertilizer. Our results provide evidence that long-term soil fertility under continuous farming was maintained, or increased, by the application of natural nutrients compared with the application of synthetic fertilizer.
DEFF Research Database (Denmark)
Hougaard, Jens Leth; Moreno-Ternero, Juan D.; Østerdal, Lars Peter Raahave
The standard problem of adjudicating conflicting claims describes a situation in which a given amount of a divisible good has to be allocated among agents who hold claims against it exceeding the available amount. This paper considers more general rationing problems in which, in addition to claims......, there exist baselines (to be interpreted as objective entitlements, ideal targets, or past consumption) that might play an important role in the allocation process. The model we present is able to accommodate real-life rationing situations, ranging from resource allocation in the public health care sector...... to international protocols for the reduction of greenhouse emissions, or water distribution in drought periods. We define a family of allocation methods for such general rationing problems - called baseline rationing rules - and provide an axiomatic characterization for it. Any baseline rationing rule within...
Directory of Open Access Journals (Sweden)
Hillman Ken
2009-12-01
Full Text Available Abstract Background To compare two approaches to the statistical analysis of the relationship between the baseline incidence of adverse events and the effect of medical emergency teams (METs. Methods Using data from a cluster randomized controlled trial (the MERIT study, we analysed the relationship between the baseline incidence of adverse events and its change from baseline to the MET activation phase using quadratic modelling techniques. We compared the findings with those obtained with conventional subgroup analysis. Results Using linear and quadratic modelling techniques, we found that each unit increase in the baseline incidence of adverse events in MET hospitals was associated with a 0.59 unit subsequent reduction in adverse events (95%CI: 0.33 to 0.86 after MET implementation and activation. This applied to cardiac arrests (0.74; 95%CI: 0.52 to 0.95, unplanned ICU admissions (0.56; 95%CI: 0.26 to 0.85 and unexpected deaths (0.68; 95%CI: 0.45 to 0.90. Control hospitals showed a similar reduction only for cardiac arrests (0.95; 95%CI: 0.56 to 1.32. Comparison using conventional subgroup analysis, on the other hand, detected no significant difference between MET and control hospitals. Conclusions Our study showed that, in the MERIT study, when there was dependence of treatment effect on baseline performance, an approach based on regression modelling helped illustrate the nature and magnitude of such dependence while sub-group analysis did not. The ability to assess the nature and magnitude of such dependence may have policy implications. Regression technique may thus prove useful in analysing data when there is a conditional treatment effect.
Kittell, David E.; Cummock, Nick R.; Son, Steven F.
2016-08-01
Small scale characterization experiments using only 1-5 g of a baseline ammonium nitrate plus fuel oil (ANFO) explosive are discussed and simulated using an ignition and growth reactive flow model. There exists a strong need for the small scale characterization of non-ideal explosives in order to adequately survey the wide parameter space in sample composition, density, and microstructure of these materials. However, it is largely unknown in the scientific community whether any useful or meaningful result may be obtained from detonation failure, and whether a minimum sample size or level of confinement exists for the experiments. In this work, it is shown that the parameters of an ignition and growth rate law may be calibrated using the small scale data, which is obtained from a 35 GHz microwave interferometer. Calibration is feasible when the samples are heavily confined and overdriven; this conclusion is supported with detailed simulation output, including pressure and reaction contours inside the ANFO samples. The resulting shock wave velocity is most likely a combined chemical-mechanical response, and simulations of these experiments require an accurate unreacted equation of state (EOS) in addition to the calibrated reaction rate. Other experiments are proposed to gain further insight into the detonation failure data, as well as to help discriminate between the role of the EOS and reaction rate in predicting the measured outcome.
Dynamic hysteresis modeling including skin effect using diffusion equation model
Hamada, Souad; Louai, Fatima Zohra; Nait-Said, Nasreddine; Benabou, Abdelkader
2016-07-01
An improved dynamic hysteresis model is proposed for the prediction of hysteresis loop of electrical steel up to mean frequencies, taking into account the skin effect. In previous works, the analytical solution of the diffusion equation for low frequency (DELF) was coupled with the inverse static Jiles-Atherton (JA) model in order to represent the hysteresis behavior for a lamination. In the present paper, this approach is improved to ensure the reproducibility of measured hysteresis loops at mean frequency. The results of simulation are compared with the experimental ones. The selected results for frequencies 50 Hz, 100 Hz, 200 Hz and 400 Hz are presented and discussed.
Dynamic hysteresis modeling including skin effect using diffusion equation model
Energy Technology Data Exchange (ETDEWEB)
Hamada, Souad, E-mail: souadhamada@yahoo.fr [LSP-IE: Research Laboratory, Electrical Engineering Department, University of Batna, 05000 Batna (Algeria); Louai, Fatima Zohra, E-mail: fz_louai@yahoo.com [LSP-IE: Research Laboratory, Electrical Engineering Department, University of Batna, 05000 Batna (Algeria); Nait-Said, Nasreddine, E-mail: n_naitsaid@yahoo.com [LSP-IE: Research Laboratory, Electrical Engineering Department, University of Batna, 05000 Batna (Algeria); Benabou, Abdelkader, E-mail: Abdelkader.Benabou@univ-lille1.fr [L2EP, Université de Lille1, 59655 Villeneuve d’Ascq (France)
2016-07-15
An improved dynamic hysteresis model is proposed for the prediction of hysteresis loop of electrical steel up to mean frequencies, taking into account the skin effect. In previous works, the analytical solution of the diffusion equation for low frequency (DELF) was coupled with the inverse static Jiles-Atherton (JA) model in order to represent the hysteresis behavior for a lamination. In the present paper, this approach is improved to ensure the reproducibility of measured hysteresis loops at mean frequency. The results of simulation are compared with the experimental ones. The selected results for frequencies 50 Hz, 100 Hz, 200 Hz and 400 Hz are presented and discussed.
Energy Technology Data Exchange (ETDEWEB)
Price, Phillip N.; Granderson, Jessica; Sohn, Michael; Addy, Nathan; Jump, David
2013-09-01
whose savings can be calculated with least error? 4. What is the state of public domain models, that is, how well do they perform, and what are the associated implications for whole-building measurement and verification (M&V)? Additional project objectives that were addressed as part of this study include: (1) clarification of the use cases and conditions for baseline modeling performance metrics, benchmarks and evaluation criteria, (2) providing guidance for determining customer suitability for baseline modeling, (3) describing the portfolio level effects of baseline model estimation errors, (4) informing PG&E’s development of EMIS technology product specifications, and (5) providing the analytical foundation for future studies about baseline modeling and saving effects of EMIS technologies. A final objective of this project was to demonstrate the application of the methodology, performance metrics, and test protocols with participating EMIS product vendors.
Unsteady panel method for complex configurations including wake modeling
CSIR Research Space (South Africa)
Van Zyl, Lourens H
2008-01-01
Full Text Available implementations of the DLM are however not very versatile in terms of geometries that can be modeled. The ZONA6 code offers a versatile surface panel body model including a separated wake model, but uses a pressure panel method for lifting surfaces. This paper...
Modeling Electric Double-Layers Including Chemical Reaction Effects
DEFF Research Database (Denmark)
Paz-Garcia, Juan Manuel; Johannesson, Björn; Ottosen, Lisbeth M.
2014-01-01
A physicochemical and numerical model for the transient formation of an electric double-layer between an electrolyte and a chemically-active flat surface is presented, based on a finite elements integration of the nonlinear Nernst-Planck-Poisson model including chemical reactions. The model works...
Circuit Modeling of a MEMS Varactor Including Dielectric Charging Dynamics
Giounanlis, P.; Andrade-Miceli, D.; Gorreta, S.; Pons-Nin, J.; Dominguez-Pumar, M.; Blokhina, E.
2016-10-01
Electrical models for MEMS varactors including the effect of dielectric charging dynamics are not available in commercial circuit simulators. In this paper a circuit model using lumped ideal elements available in the Cadence libraries and a basic Verilog-A model, has been implemented. The model has been used to simulate the dielectric charging in function of time and its effects over the MEMS capacitance value.
Including investment risk in large-scale power market models
DEFF Research Database (Denmark)
Lemming, Jørgen Kjærgaard; Meibom, P.
2003-01-01
can be included in large-scale partial equilibrium models of the power market. The analyses are divided into a part about risk measures appropriate for power market investors and a more technical part about the combination of a risk-adjustment model and a partial-equilibrium model. To illustrate......Long-term energy market models can be used to examine investments in production technologies, however, with market liberalisation it is crucial that such models include investment risks and investor behaviour. This paper analyses how the effect of investment risk on production technology selection...... the analyses quantitatively, a framework based on an iterative interaction between the equilibrium model and a separate risk-adjustment module was constructed. To illustrate the features of the proposed modelling approach we examined how uncertainty in demand and variable costs affects the optimal choice...
Kumar, Sumeet; Heister, Stephen D.; Xu, Xianfan; Salvador, James R.; Meisner, Gregory P.
2013-04-01
A numerical model has been developed to simulate coupled thermal and electrical energy transfer processes in a thermoelectric generator (TEG) designed for automotive waste heat recovery systems. This model is capable of computing the overall heat transferred, the electrical power output, and the associated pressure drop for given inlet conditions of the exhaust gas and the available TEG volume. Multiple-filled skutterudites and conventional bismuth telluride are considered for thermoelectric modules (TEMs) for conversion of waste heat from exhaust into usable electrical power. Heat transfer between the hot exhaust gas and the hot side of the TEMs is enhanced with the use of a plate-fin heat exchanger integrated within the TEG and using liquid coolant on the cold side. The TEG is discretized along the exhaust flow direction using a finite-volume method. Each control volume is modeled as a thermal resistance network which consists of integrated submodels including a heat exchanger and a thermoelectric device. The pressure drop along the TEG is calculated using standard pressure loss correlations and viscous drag models. The model is validated to preserve global energy balances and is applied to analyze a prototype TEG with data provided by General Motors. Detailed results are provided for local and global heat transfer and electric power generation. In the companion paper, the model is then applied to consider various TEG topologies using skutterudite and bismuth telluride TEMs.
Michel, Patrik; Odier, Céline; Rutgers, Matthieu; Reichhart, Marc; Maeder, Philippe; Meuli, Reto; Wintermark, Max; Maghraoui, Ali; Faouzi, Mohamed; Croquelois, Alexandre; Ntaios, George
2010-11-01
Stroke registries are valuable tools for obtaining information about stroke epidemiology and management. The Acute STroke Registry and Analysis of Lausanne (ASTRAL) prospectively collects epidemiological, clinical, laboratory and multimodal brain imaging data of acute ischemic stroke patients in the Centre Hospitalier Universitaire Vaudois (CHUV). Here, we provide design and methods used to create ASTRAL and present baseline data of our patients (2003 to 2008). All consecutive patients admitted to CHUV between January 1, 2003 and December 31, 2008 with acute ischemic stroke within 24 hours of symptom onset were included in ASTRAL. Patients arriving beyond 24 hours, with transient ischemic attack, intracerebral hemorrhage, subarachnoidal hemorrhage, or cerebral sinus venous thrombosis, were excluded. Recurrent ischemic strokes were registered as new events. Between 2003 and 2008, 1633 patients and 1742 events were registered in ASTRAL. There was a preponderance of males, even in the elderly. Cardioembolic stroke was the most frequent type of stroke. Most strokes were of minor severity (National Institute of Health Stroke Scale [NIHSS] score ≤ 4 in 40.8% of patients). Cardioembolic stroke and dissections presented with the most severe clinical picture. There was a significant number of patients with unknown onset stroke, including wake-up stroke (n=568, 33.1%). Median time from last-well time to hospital arrival was 142 minutes for known onset and 759 minutes for unknown-onset stroke. The rate of intravenous or intraarterial thrombolysis between 2003 and 2008 increased from 10.8% to 20.8% in patients admitted within 24 hours of last-well time. Acute brain imaging was performed in 1695 patients (97.3%) within 24 hours. In 1358 patients (78%) who underwent acute computed tomography angiography, 717 patients (52.8%) had significant abnormalities. Of the 1068 supratentorial stroke patients who underwent acute perfusion computed tomography (61.3%), focal hypoperfusion
Progressive IRP Models for Power Resources Including EPP
Directory of Open Access Journals (Sweden)
Yiping Zhu
2017-01-01
Full Text Available In the view of optimizing regional power supply and demand, the paper makes effective planning scheduling of supply and demand side resources including energy efficiency power plant (EPP, to achieve the target of benefit, cost, and environmental constraints. In order to highlight the characteristics of different supply and demand resources in economic, environmental, and carbon constraints, three planning models with progressive constraints are constructed. Results of three models by the same example show that the best solutions to different models are different. The planning model including EPP has obvious advantages considering pollutant and carbon emission constraints, which confirms the advantages of low cost and emissions of EPP. The construction of progressive IRP models for power resources considering EPP has a certain reference value for guiding the planning and layout of EPP within other power resources and achieving cost and environmental objectives.
Modeling and Simulation of Offshore Wind Power Platform for 5 MW Baseline NREL Turbine.
Roni Sahroni, Taufik
2015-01-01
This paper presents the modeling and simulation of offshore wind power platform for oil and gas companies. Wind energy has become the fastest growing renewable energy in the world and major gains in terms of energy generation are achievable when turbines are moved offshore. The objective of this project is to propose new design of an offshore wind power platform. Offshore wind turbine (OWT) is composed of three main structures comprising the rotor/blades, the tower nacelle, and the supporting structure. The modeling analysis was focused on the nacelle and supporting structure. The completed final design was analyzed using finite element modeling tool ANSYS to obtain the structure's response towards loading conditions and to ensure it complies with guidelines laid out by classification authority Det Norske Veritas. As a result, a new model of the offshore wind power platform for 5 MW Baseline NREL turbine was proposed.
Modeling and Simulation of Offshore Wind Power Platform for 5 MW Baseline NREL Turbine
Roni Sahroni, Taufik
2015-01-01
This paper presents the modeling and simulation of offshore wind power platform for oil and gas companies. Wind energy has become the fastest growing renewable energy in the world and major gains in terms of energy generation are achievable when turbines are moved offshore. The objective of this project is to propose new design of an offshore wind power platform. Offshore wind turbine (OWT) is composed of three main structures comprising the rotor/blades, the tower nacelle, and the supporting structure. The modeling analysis was focused on the nacelle and supporting structure. The completed final design was analyzed using finite element modeling tool ANSYS to obtain the structure's response towards loading conditions and to ensure it complies with guidelines laid out by classification authority Det Norske Veritas. As a result, a new model of the offshore wind power platform for 5 MW Baseline NREL turbine was proposed. PMID:26550605
DEFF Research Database (Denmark)
Kerstjens, Huib A M; Moroni-Zentgraf, Petra; Tashkin, Donald P
2016-01-01
exacerbations and asthma worsening, and improved asthma symptom control, independent of a broad range of baseline characteristics, as add-on to ICS plus LABAs in patients with severe symptomatic asthma. TRIAL REGISTRY: ClinicalTrials.gov; numbers NCT00772538 and NCT00776984 URL: www.clinicaltrials.gov....
Boon, ME; Claasen, HHV; Kok, LP
OBJECTIVE: An overgrowth of coccoid bacilli in the absence of lactobacilli (bacterial vaginosis) is considered a sign of a "disturbed" vaginal ecologic system. The aim of this study was to establish the baseline prevalence of genital infections and of a disturbed vaginal ecologic system and their
Boon, ME; Claasen, HHV; Kok, LP
2002-01-01
OBJECTIVE: An overgrowth of coccoid bacilli in the absence of lactobacilli (bacterial vaginosis) is considered a sign of a "disturbed" vaginal ecologic system. The aim of this study was to establish the baseline prevalence of genital infections and of a disturbed vaginal ecologic system and their re
Boon, ME; Claasen, HHV; Kok, LP
2002-01-01
OBJECTIVE: An overgrowth of coccoid bacilli in the absence of lactobacilli (bacterial vaginosis) is considered a sign of a "disturbed" vaginal ecologic system. The aim of this study was to establish the baseline prevalence of genital infections and of a disturbed vaginal ecologic system and their re
Energy Technology Data Exchange (ETDEWEB)
Johnson, P.E.; Joy, D.S.
1995-02-01
The potential impacts associated with the transportation of hazardous materials are important to shippers, carriers, and the general public. This is particularly true for shipments of radioactive material. The shippers are primarily concerned with safety, security, efficiency, and equipment requirements. The carriers are concerned with the potential impact that radioactive shipments may have on their operations--particularly if such materials are involved in an accident. The general public has also expressed concerns regarding the safety of transporting radioactive and other hazardous materials through their communities. Because transportation routes are a central concern in hazardous material transport, the prediction of likely routes is the first step toward resolution of these issues. In response to these routing needs, several models have been developed over the past fifteen years at Oak Ridge National Laboratory (ORNL). The HIGHWAY routing model is used to predict routes for truck transportation, the INTERLINE routing model is used to predict both rail and barge routes, and the AIRPORT locator model is used to determine airports with specified criteria near a specific location. As part of the ongoing improvement of the US Department of Energy`s (DOE) Environmental Management Transportation Management Division`s (EM-261) computer systems and development efforts, a Baseline Requirements Assessment Session on the HIGHWAY, INTERLINE, and AIRPORT models was held at ORNL on April 27, 1994. The purpose of this meeting was to discuss the existing capabilities of the models and data bases and to review enhancements of the models and data bases to expand their usefulness. The results of the Baseline Requirements Assessment Section will be discussed in this report. The discussions pertaining to the different models are contained in separate sections.
Modeling heart rate variability including the effect of sleep stages
Soliński, Mateusz; Gierałtowski, Jan; Żebrowski, Jan
2016-02-01
We propose a model for heart rate variability (HRV) of a healthy individual during sleep with the assumption that the heart rate variability is predominantly a random process. Autonomic nervous system activity has different properties during different sleep stages, and this affects many physiological systems including the cardiovascular system. Different properties of HRV can be observed during each particular sleep stage. We believe that taking into account the sleep architecture is crucial for modeling the human nighttime HRV. The stochastic model of HRV introduced by Kantelhardt et al. was used as the initial starting point. We studied the statistical properties of sleep in healthy adults, analyzing 30 polysomnographic recordings, which provided realistic information about sleep architecture. Next, we generated synthetic hypnograms and included them in the modeling of nighttime RR interval series. The results of standard HRV linear analysis and of nonlinear analysis (Shannon entropy, Poincaré plots, and multiscale multifractal analysis) show that—in comparison with real data—the HRV signals obtained from our model have very similar properties, in particular including the multifractal characteristics at different time scales. The model described in this paper is discussed in the context of normal sleep. However, its construction is such that it should allow to model heart rate variability in sleep disorders. This possibility is briefly discussed.
From groundwater baselines to numerical groundwater flow modelling for the Milan metropolitan area
Crosta, Giovanni B.; Frattini, Paolo; Peretti, Lidia; Villa, Federica; Gorla, Maurizio
2015-04-01
Contamination of major aquifers in highly densely populated areas is a major concern for stakeholders involved in the use and protection of groundwater resources. Sustainable groundwater withdrawal and management, and the identification of trends in groundwater contamination require a careful hydrochemical baseline characterization. This characterization is fundamental to investigate the presence and evolutionary trend of contaminants. In fact, it allows recovering and understanding: the spatial-temporal trend of contamination; the relative age of the contamination episodes; the reasons for anomalous behavior of some compounds during migration to and in the groundwater; the associations with which some contaminants can be found; the different behaviors in phreatic and semi-confined and confined aquifers. To attain such a characterization for the Milan metropolitan area (about 2,500 km2, ca 4.000.000 inhabitants, Lombardy, Italy), we carried out three main activities. (1) Collection of complete and reliable datasets concerning the geological, hydrogeological and hydrochemical (over 60,000 chemical analysis since 2003 to 2013) characteristics of the area and of the involved aquifers. This activity was very demanding because the available data are provided by different authorities (Lombardy Region, Provinces, Lombardy Environmental Agency - ARPA Lombardia, public own companies in charge of water system managements) in raw format and with different database standard, which required a large effort of manual verification and harmonization. (2) Completion of a hydrochemical characterization of the metropolitan area aquifers by classical statistical and multivariate statistical analyses, in order to define a baseline both for some major physical chemical characteristics and for the most relevant contaminants. (3) Development of a three dimensional hydrogeological model for the metropolitan area starting from the above listed datasets and existing models. This model will
A hydrodynamic model for granular material flows including segregation effects
Gilberg, Dominik; Klar, Axel; Steiner, Konrad
2017-06-01
The simulation of granular flows including segregation effects in large industrial processes using particle methods is accurate, but very time-consuming. To overcome the long computation times a macroscopic model is a natural choice. Therefore, we couple a mixture theory based segregation model to a hydrodynamic model of Navier-Stokes-type, describing the flow behavior of the granular material. The granular flow model is a hybrid model derived from kinetic theory and a soil mechanical approach to cover the regime of fast dilute flow, as well as slow dense flow, where the density of the granular material is close to the maximum packing density. Originally, the segregation model has been formulated by Thornton and Gray for idealized avalanches. It is modified and adapted to be in the preferred form for the coupling. In the final coupled model the segregation process depends on the local state of the granular system. On the other hand, the granular system changes as differently mixed regions of the granular material differ i.e. in the packing density. For the modeling process the focus lies on dry granular material flows of two particle types differing only in size but can be easily extended to arbitrary granular mixtures of different particle size and density. To solve the coupled system a finite volume approach is used. To test the model the rotational mixing of small and large particles in a tumbler is simulated.
Synaptic channel model including effects of spike width variation
2015-01-01
Synaptic Channel Model Including Effects of Spike Width Variation Hamideh Ramezani Next-generation and Wireless Communications Laboratory (NWCL) Department of Electrical and Electronics Engineering Koc University, Istanbul, Turkey Ozgur B. Akan Next-generation and Wireless Communications Laboratory (NWCL) Department of Electrical and Electronics Engineering Koc University, Istanbul, Turkey ABSTRACT An accu...
A sonic boom propagation model including mean flow atmospheric effects
Salamone, Joe; Sparrow, Victor W.
2012-09-01
This paper presents a time domain formulation of nonlinear lossy propagation in onedimension that also includes the effects of non-collinear mean flow in the acoustic medium. The model equation utilized is an augmented Burgers equation that includes the effects of nonlinearity, geometric spreading, atmospheric stratification, and also absorption and dispersion due to thermoviscous and molecular relaxation effects. All elements of the propagation are implemented in the time domain and the effects of non-collinear mean flow are accounted for in each term of the model equation. Previous authors have presented methods limited to showing the effects of wind on ray tracing and/or using an effective speed of sound in their model equation. The present work includes the effects of mean flow for all terms included in the augmented Burgers equation with all of the calculations performed in the time-domain. The capability to include the effects of mean flow in the acoustic medium allows one to make predictions more representative of real-world atmospheric conditions. Examples are presented for nonlinear propagation of N-waves and shaped sonic booms. [Work supported by Gulfstream Aerospace Corporation.
A Baseline Patient Model to Support Testing of Medical Cyber-Physical Systems.
Silva, Lenardo C; Perkusich, Mirko; Almeida, Hyggo O; Perkusich, Angelo; Lima, Mateus A M; Gorgônio, Kyller C
2015-01-01
Medical Cyber-Physical Systems (MCPS) are currently a trending topic of research. The main challenges are related to the integration and interoperability of connected medical devices, patient safety, physiologic closed-loop control, and the verification and validation of these systems. In this paper, we focus on patient safety and MCPS validation. We present a formal patient model to be used in health care systems validation without jeopardizing the patient's health. To determine the basic patient conditions, our model considers the four main vital signs: heart rate, respiratory rate, blood pressure and body temperature. To generate the vital signs we used regression models based on statistical analysis of a clinical database. Our solution should be used as a starting point for a behavioral patient model and adapted to specific clinical scenarios. We present the modeling process of the baseline patient model and show its evaluation. The conception process may be used to build different patient models. The results show the feasibility of the proposed model as an alternative to the immediate need for clinical trials to test these medical systems.
Baumer, Andreas; Bittermann, Kai; Klüver, Nils; Escher, Beate I
2017-07-19
In numerous studies on the toxicity of ionisable organic chemicals, it has been shown that the toxicity was typically higher, when larger fractions of the neutral species were present. This observation was explained in some cases by slower uptake of charged species. In other cases it was suggested that the neutral species has intrinsically higher toxicity than the charged species or is alone responsible for the toxicity. However, even permanently charged and organic chemicals with multiple acid and base functional groups and zwitterions are toxic. We set out to reconcile the divergent views and to compare the various existing models for describing the pH-dependence of toxicity with the goal to derive one model that is valid independent of the type and number of charges on the molecule. To achieve this goal we measured the cytotoxicity of 18 acidic, 15 basic and 9 multiprotic/zwitterionic pharmaceuticals at pH 5.5 to pH 9 with the bioluminescence inhibition test using Aliivibrio fischeri (Microtox assay). This assay is useful for an evaluation of various models to describe pH-dependent toxicity because the majority of chemicals act as baseline toxicants in this 30 min cytotoxicity assay. Therefore baseline toxicity with constant membrane concentrations of the sum of all chemical species of approximately 200 mmol kglip(-1) served for the validation of the suitability of the various tested models. We confirmed that most tested pharmaceuticals acted as baseline toxicants in this assay at all examined pH values, when toxicity was modeled with a mixture model of concentration addition between the neutral species and all charged species. An ion trapping model, that assumes that the membrane permeability of charged species is kinetically limited, improved model predictions for some pharmaceuticals and pH values. However, neither unhindered uptake nor no uptake of the charged species were ideal models; the reality lies presumably between the two limiting cases with a slower
Energy Technology Data Exchange (ETDEWEB)
Maurakis, Eugene G
2010-10-01
Objectives of the two-year study were to (1) establish baselines for fish and macroinvertebrate community structures in two mid-Atlantic lower Piedmont watersheds (Quantico Creek, a pristine forest watershed; and Cameron Run, an urban watershed, Virginia) that can be used to monitor changes relative to the impacts related to climate change in the future; (2) create mathematical expressions to model fish species richness and diversity, and macroinvertebrate taxa and macroinvertebrate functional feeding group taxa richness and diversity that can serve as a baseline for future comparisons in these and other watersheds in the mid-Atlantic region; and (3) heighten people’s awareness, knowledge and understanding of climate change and impacts on watersheds in a laboratory experience and interactive exhibits, through internship opportunities for undergraduate and graduate students, a week-long teacher workshop, and a website about climate change and watersheds. Mathematical expressions modeled fish and macroinvertebrate richness and diversity accurately well during most of the six thermal seasons where sample sizes were robust. Additionally, hydrologic models provide the basis for estimating flows under varying meteorological conditions and landscape changes. Continuations of long-term studies are requisite for accurately teasing local human influences (e.g. urbanization and watershed alteration) from global anthropogenic impacts (e.g. climate change) on watersheds. Effective and skillful translations (e.g. annual potential exposure of 750,000 people to our inquiry-based laboratory activities and interactive exhibits in Virginia) of results of scientific investigations are valuable ways of communicating information to the general public to enhance their understanding of climate change and its effects in watersheds.
A model of Barchan dunes including lateral shear stress.
Schwämmle, V; Herrmann, H J
2005-01-01
Barchan dunes are found where sand availability is low and wind direction quite constant. The two dimensional shear stress of the wind field and the sand movement by saltation and avalanches over a barchan dune are simulated. The model with one dimensional shear stress is extended including surface diffusion and lateral shear stress. The resulting final shape is compared to the results of the model with a one dimensional shear stress and confirmed by comparison to measurements. We found agreement and improvements with respect to the model with one dimensional shear stress. Additionally, a characteristic edge at the center of the windward side is discovered which is also observed for big barchans. Diffusion effects reduce this effect for small dunes.
Modeling the worldwide spread of pandemic influenza: baseline case and containment interventions.
Directory of Open Access Journals (Sweden)
Vittoria Colizza
2007-01-01
Full Text Available BACKGROUND: The highly pathogenic H5N1 avian influenza virus, which is now widespread in Southeast Asia and which diffused recently in some areas of the Balkans region and Western Europe, has raised a public alert toward the potential occurrence of a new severe influenza pandemic. Here we study the worldwide spread of a pandemic and its possible containment at a global level taking into account all available information on air travel. METHODS AND FINDINGS: We studied a metapopulation stochastic epidemic model on a global scale that considers airline travel flow data among urban areas. We provided a temporal and spatial evolution of the pandemic with a sensitivity analysis of different levels of infectiousness of the virus and initial outbreak conditions (both geographical and seasonal. For each spreading scenario we provided the timeline and the geographical impact of the pandemic in 3,100 urban areas, located in 220 different countries. We compared the baseline cases with different containment strategies, including travel restrictions and the therapeutic use of antiviral (AV drugs. We investigated the effect of the use of AV drugs in the event that therapeutic protocols can be carried out with maximal coverage for the populations in all countries. In view of the wide diversity of AV stockpiles in different regions of the world, we also studied scenarios in which only a limited number of countries are prepared (i.e., have considerable AV supplies. In particular, we compared different plans in which, on the one hand, only prepared and wealthy countries benefit from large AV resources, with, on the other hand, cooperative containment scenarios in which countries with large AV stockpiles make a small portion of their supplies available worldwide. CONCLUSIONS: We show that the inclusion of air transportation is crucial in the assessment of the occurrence probability of global outbreaks. The large-scale therapeutic usage of AV drugs in all hit
Goldilocks Models of Higher-Dimensional Inflation (including modulus stabilization)
Burgess, C P; Hayman, Peter; Patil, Subodh P
2016-01-01
We explore the mechanics of inflation in simplified extra-dimensional models involving an inflaton interacting with the Einstein-Maxwell system in two extra dimensions. The models are Goldilocks-like in that they are just complicated enough to include a mechanism to stabilize the extra-dimensional size, yet simple enough to solve the full 6D field equations using basic tools. The solutions are not limited to the effective 4D regime with H m_KK, but when they do standard 4D fluctuation calculations need not apply. When in a 4D regime the solutions predict eta ~ 0 hence n_s ~ 0.96 and r ~ 0.096 and so are ruled out if tensor modes remain unseen. Analysis of general parameters is difficult without a full 6D fluctuation calculation.
Kinetic models of gene expression including non-coding RNAs
Zhdanov, Vladimir P.
2011-03-01
In cells, genes are transcribed into mRNAs, and the latter are translated into proteins. Due to the feedbacks between these processes, the kinetics of gene expression may be complex even in the simplest genetic networks. The corresponding models have already been reviewed in the literature. A new avenue in this field is related to the recognition that the conventional scenario of gene expression is fully applicable only to prokaryotes whose genomes consist of tightly packed protein-coding sequences. In eukaryotic cells, in contrast, such sequences are relatively rare, and the rest of the genome includes numerous transcript units representing non-coding RNAs (ncRNAs). During the past decade, it has become clear that such RNAs play a crucial role in gene expression and accordingly influence a multitude of cellular processes both in the normal state and during diseases. The numerous biological functions of ncRNAs are based primarily on their abilities to silence genes via pairing with a target mRNA and subsequently preventing its translation or facilitating degradation of the mRNA-ncRNA complex. Many other abilities of ncRNAs have been discovered as well. Our review is focused on the available kinetic models describing the mRNA, ncRNA and protein interplay. In particular, we systematically present the simplest models without kinetic feedbacks, models containing feedbacks and predicting bistability and oscillations in simple genetic networks, and models describing the effect of ncRNAs on complex genetic networks. Mathematically, the presentation is based primarily on temporal mean-field kinetic equations. The stochastic and spatio-temporal effects are also briefly discussed.
Progress Towards an LES Wall Model Including Unresolved Roughness
Craft, Kyle; Redman, Andrew; Aikens, Kurt
2015-11-01
Wall models used in large eddy simulations (LES) are often based on theories for hydraulically smooth walls. While this is reasonable for many applications, there are also many where the impact of surface roughness is important. A previously developed wall model has been used primarily for jet engine aeroacoustics. However, jet simulations have not accurately captured thick initial shear layers found in some experimental data. This may partly be due to nozzle wall roughness used in the experiments to promote turbulent boundary layers. As a result, the wall model is extended to include the effects of unresolved wall roughness through appropriate alterations to the log-law. The methodology is tested for incompressible flat plate boundary layers with different surface roughness. Correct trends are noted for the impact of surface roughness on the velocity profile. However, velocity deficit profiles and the Reynolds stresses do not collapse as well as expected. Possible reasons for the discrepancies as well as future work will be presented. This work used the Extreme Science and Engineering Discovery Environment (XSEDE), which is supported by National Science Foundation grant number ACI-1053575. Computational resources on TACC Stampede were provided under XSEDE allocation ENG150001.
Directory of Open Access Journals (Sweden)
Antonio Montresor
2016-04-01
Full Text Available Estimating the reduction in levels of infection during implementation of soil-transmitted helminth (STH control programmes is important to measure their performance and to plan interventions. Markov modelling techniques have been used with some success to predict changes in STH prevalence following treatment in Viet Nam. The model is stationary and to date, the prediction has been obtained by calculating the transition probabilities between the different classes of intensity following the first year of drug distribution and assuming that these remain constant in subsequent years. However, to run this model longitudinal parasitological data (including intensity of infection are required for two consecutive years from at least 200 individuals. Since this amount of data is not often available from STH control programmes, the possible application of the model in control programme is limited. The present study aimed to address this issue by adapting the existing Markov model to allow its application when a more limited amount of data is available and to test the predictive capacities of these simplified models.We analysed data from field studies conducted with different combination of three parameters: (i the frequency of drug administration; (ii the drug distributed; and (iii the target treatment population (entire population or school-aged children only. This analysis allowed us to define 10 sets of standard transition probabilities to be used to predict prevalence changes when only baseline data are available (simplified model 1. We also formulated three equations (one for each STH parasite to calculate the predicted prevalence of the different classes of intensity from the total prevalence. These equations allowed us to design a simplified model (SM2 to obtain predictions when the classes of intensity at baseline were not known. To evaluate the performance of the simplified models, we collected data from the scientific literature on changes in
Self-consistent modeling of CFETR baseline scenarios for steady-state operation
Chen, Jiale; Jian, Xiang; Chan, Vincent S.; Li, Zeyu; Deng, Zhao; Li, Guoqiang; Guo, Wenfeng; Shi, Nan; Chen, Xi; CFETR Physics Team
2017-07-01
Integrated modeling for core plasma is performed to increase confidence in the proposed baseline scenario in the 0D analysis for the China Fusion Engineering Test Reactor (CFETR). The steady-state scenarios are obtained through the consistent iterative calculation of equilibrium, transport, auxiliary heating and current drives (H&CD). Three combinations of H&CD schemes (NB + EC, NB + EC + LH, and EC + LH) are used to sustain the scenarios with q min > 2 and fusion power of ˜70-150 MW. The predicted power is within the target range for CFETR Phase I, although the confinement based on physics models is lower than that assumed in 0D analysis. Ideal MHD stability analysis shows that the scenarios are stable against n = 1-10 ideal modes, where n is the toroidal mode number. Optimization of RF current drive for the RF-only scenario is also presented. The simulation workflow for core plasma in this work provides a solid basis for a more extensive research and development effort for the physics design of CFETR.
Numerical Modeling of Electroacoustic Logging Including Joule Heating
Plyushchenkov, Boris D.; Nikitin, Anatoly A.; Turchaninov, Victor I.
It is well known that electromagnetic field excites acoustic wave in a porous elastic medium saturated with fluid electrolyte due to electrokinetic conversion effect. Pride's equations describing this process are written in isothermal approximation. Update of these equations, which allows to take influence of Joule heating on acoustic waves propagation into account, is proposed here. This update includes terms describing the initiation of additional acoustic waves excited by thermoelastic stresses and the heat conduction equation with right side defined by Joule heating. Results of numerical modeling of several problems of propagation of acoustic waves excited by an electric field source with and without consideration of Joule heating effect in their statements are presented. From these results, it follows that influence of Joule heating should be taken into account at the numerical simulation of electroacoustic logging and at the interpretation of its log data.
Goldilocks models of higher-dimensional inflation (including modulus stabilization)
Burgess, C. P.; Enns, Jared J. H.; Hayman, Peter; Patil, Subodh P.
2016-08-01
We explore the mechanics of inflation within simplified extra-dimensional models involving an inflaton interacting with the Einstein-Maxwell system in two extra dimensions. The models are Goldilocks-like inasmuch as they are just complicated enough to include a mechanism to stabilize the extra-dimensional size (or modulus), yet simple enough to solve explicitly the full extra-dimensional field equations using only simple tools. The solutions are not restricted to the effective 4D regime with H ll mKK (the latter referring to the characteristic mass splitting of the Kaluza-Klein excitations) because the full extra-dimensional Einstein equations are solved. This allows an exploration of inflationary physics in a controlled calculational regime away from the usual four-dimensional lamp-post. The inclusion of modulus stabilization is important because experience with string models teaches that this is usually what makes models fail: stabilization energies easily dominate the shallow potentials required by slow roll and so open up directions to evolve that are steeper than those of the putative inflationary direction. We explore (numerically and analytically) three representative kinds of inflationary scenarios within this simple setup. In one the radion is trapped in an inflaton-dependent local minimum whose non-zero energy drives inflation. Inflation ends as this energy relaxes to zero when the inflaton finds its own minimum. The other two involve power-law scaling solutions during inflation. One of these is a dynamical attractor whose features are relatively insensitive to initial conditions but whose slow-roll parameters cannot be arbitrarily small; the other is not an attractor but can roll much more slowly, until eventually transitioning to the attractor. The scaling solutions can satisfy H > mKK, but when they do standard 4D fluctuation calculations need not apply. When in a 4D regime the solutions predict η simeq 0 and so r simeq 0.11 when ns simeq 0.96 and so
Jian, Xiang; Chen, Jiale; Chan, Vincent S.; Zhuang, Ge; Li, Guoqiang; Deng, Zhao; Shi, Nan; Xu, Guoliang; Staebler, Gary M.; Guo, Wenfeng
2017-04-01
The optimization of a CFETR baseline scenario (Chan et al 2015 Nucl. Fusion 55 023017) with an electron cyclotron (EC) wave and neutral beam (NB) is performed using a multi-dimensional code suite. TGLF and NEO are used to calculate turbulent and neoclassical transport. The evaluation of sources and sinks, as well as the current evolution, are performed using ONETWO, and the equilibrium is updated using EFIT. The pedestal is consistent with the EPED model. Rotation shear is controlled using NB. It has been found that both fusion gain Q and NB power deposited in the edge increase with decreasing NB energy, with NB providing current drive, torque, energy and particle source simultaneously. By using an optimized combination of two NBs, Q can be kept at a high level while the NB edge power is reduced. Pedestal collisionality is controlled to find an optimization path for Q by trading off between the pedestal density and temperature with the pedestal pressure fixed. It has been found that Q increases with pedestal collisionality, while the density peaking factor (DPF) remains almost unchanged. The invariance of DPF can be explained by the change of the dominant type of turbulence from the core to the edge (i.e. trapped electron mode in the core and ion temperature gradient mode at the edge), and collisionality has the opposite effect on particle transport for these two modes. A weaker dependence of DPF on collisionality makes a higher density operation more favorable for fusion gain.
Kellam, S G; Werthamer-Larsson, L; Dolan, L J; Brown, C H; Mayer, L S; Rebok, G W; Anthony, J C; Laudolff, J; Edelsohn, G
1991-08-01
Describes a conceptual framework for identifying and targeting developmental antecedents in early childhood that have been shown in previous work to predict delinquency and violent behavior, heavy drug use, depression, and other psychiatric symptoms and possibly disorders in late adolescence and into adulthood. Criteria are described that guided choices of targets for two epidemiologically based, randomized preventive trials carried out in 19 elementary schools in the eastern half of Baltimore, involving more than 2,400 first-grade children over the course of first and second grades. Baseline models derived from the first of two cohorts show the evolving patterns of concurrence among the target antecedents. The central role of concentration problems emerged. From Fall to Spring in first grade, concentration problems led to shy and aggressive behavior and poor achievement in both genders and to depressive symptoms among girls. There was evidence for reciprocal relationships in girls. For example, depressive symptoms led to poor achievement in both girls and boys, whereas poor achievement led to depressive symptoms in girls but not boys, at least over the first-grade year. These results provide important epidemiological data relevant to the developmental paths leading to the problem outcomes and suggest preventive trials.
Including spatial data in nutrient balance modelling on dairy farms
van Leeuwen, Maricke; van Middelaar, Corina; Stoof, Cathelijne; Oenema, Jouke; Stoorvogel, Jetse; de Boer, Imke
2017-04-01
The Annual Nutrient Cycle Assessment (ANCA) calculates the nitrogen (N) and phosphorus (P) balance at a dairy farm, while taking into account the subsequent nutrient cycles of the herd, manure, soil and crop components. Since January 2016, Dutch dairy farmers are required to use ANCA in order to increase understanding of nutrient flows and to minimize nutrient losses to the environment. A nutrient balance calculates the difference between nutrient inputs and outputs. Nutrients enter the farm via purchased feed, fertilizers, deposition and fixation by legumes (nitrogen), and leave the farm via milk, livestock, manure, and roughages. A positive balance indicates to which extent N and/or P are lost to the environment via gaseous emissions (N), leaching, run-off and accumulation in soil. A negative balance indicates that N and/or P are depleted from soil. ANCA was designed to calculate average nutrient flows on farm level (for the herd, manure, soil and crop components). ANCA was not designed to perform calculations of nutrient flows at the field level, as it uses averaged nutrient inputs and outputs across all fields, and it does not include field specific soil characteristics. Land management decisions, however, such as the level of N and P application, are typically taken at the field level given the specific crop and soil characteristics. Therefore the information that ANCA provides is likely not sufficient to support farmers' decisions on land management to minimize nutrient losses to the environment. This is particularly a problem when land management and soils vary between fields. For an accurate estimate of nutrient flows in a given farming system that can be used to optimize land management, the spatial scale of nutrient inputs and outputs (and thus the effect of land management and soil variation) could be essential. Our aim was to determine the effect of the spatial scale of nutrient inputs and outputs on modelled nutrient flows and nutrient use efficiencies
A Discrete Velocity Traffic Kinetic Model Including Desired Speed
Directory of Open Access Journals (Sweden)
Shoufeng Lu
2013-05-01
Full Text Available We introduce the desired speed variable into the table of games and formulate a new table of games and the corresponding discrete traffic kinetic model. We use the hybrid programming technique of VB and MATLAB to develop the program. Lastly, we compared the proposed model result and the detector data. The results show that the proposed model can describe the traffic flow evolution.
Semi-holographic model including the radiation component
del Campo, Sergio; Magaña, Juan; Villanueva, J R
2014-01-01
In this letter we study the semi holographic model which corresponds to the radiative version of the model proposed by Zhang et al. (Phys. Lett. B 694 (2010), 177) and revisited by C\\'ardenas et al. (Mon. Not. Roy. Astron. Soc. 438 (2014), 3603). This inclusion makes the model more realistic, so allows us to test it with current observational data and then answer if the inconsistency reported by C\\'ardenas et al. is relaxed.
A Fault Evolution Model Including the Rupture Dynamic Simulation
Wu, Y.; Chen, X.
2011-12-01
We perform a preliminary numerical simulation of seismicity and stress evolution along a strike-slip fault in a 3D elastic half space. Following work of Ben-Zion (1996), the fault geometry is devised as a vertical plane which is about 70 km long and 17 km wide, comparable to the size of San Andreas Fault around Parkfield. The loading mechanism is described by "backslip" method. The fault failure is governed by a static/kinetic friction law, and induced stress transfer is calculated with Okada's static solution. In order to track the rupture propagation in detail, we allow induced stress to propagate through the medium at the shear wave velocity by introducing a distance-dependent time delay to responses to stress changes. Current simulation indicates small to moderate earthquakes following the Gutenberg-Richter law and quasi-periodical characteristic large earthquakes, which are consistent with previous work by others. Next we will consider introducing a more realistic friction law, namely, the laboratory-derived rate- and state- dependent law, which can simulate more realistic and complicated sliding behavior such as the stable and unstable slip, the aseismic sliding and the slip nucleation process. In addition, the long duration of aftershocks is expected to be reproduced due to this time-dependent friction law, which is not available in current seismicity simulation. The other difference from previous work is that we are trying to include the dynamic ruptures in this study. Most previous study on seismicity simulation is based on the static solution when dealing with failure induced stress changes. However, studies of numerical simulation of rupture dynamics have revealed lots of important details which are missing in the quasi-static/quasi- dynamic simulation. For example, dynamic simulations indicate that the slip on the ground surface becomes larger if the dynamic rupture process reaches the free surface. The concentration of stress on the propagating crack
Evacuation modeling including traveler information and compliance behavior
Pel, A.J.; Hoogendoorn, S.P.; Bliemer, M.C.J.
2010-01-01
Traffic simulation models are often used to support decisions when planning an evacuation. Scenario analyses based on these models then typically focus on traffic dynamics and the effect of traffic control measures in order to locate possible bottlenecks and predict evacuation times. A clear approac
Global atmospheric model for mercury including oxidation by bromine atoms
Directory of Open Access Journals (Sweden)
C. D. Holmes
2010-12-01
Full Text Available Global models of atmospheric mercury generally assume that gas-phase OH and ozone are the main oxidants converting Hg^{0} to Hg^{II} and thus driving mercury deposition to ecosystems. However, thermodynamic considerations argue against the importance of these reactions. We demonstrate here the viability of atomic bromine (Br as an alternative Hg^{0} oxidant. We conduct a global 3-D simulation with the GEOS-Chem model assuming gas-phase Br to be the sole Hg^{0} oxidant (Hg + Br model and compare to the previous version of the model with OH and ozone as the sole oxidants (Hg + OH/O_{3} model. We specify global 3-D Br concentration fields based on our best understanding of tropospheric and stratospheric Br chemistry. In both the Hg + Br and Hg + OH/O_{3} models, we add an aqueous photochemical reduction of Hg^{II} in cloud to impose a tropospheric lifetime for mercury of 6.5 months against deposition, as needed to reconcile observed total gaseous mercury (TGM concentrations with current estimates of anthropogenic emissions. This added reduction would not be necessary in the Hg + Br model if we adjusted the Br oxidation kinetics downward within their range of uncertainty. We find that the Hg + Br and Hg + OH/O_{3} models are equally capable of reproducing the spatial distribution of TGM and its seasonal cycle at northern mid-latitudes. The Hg + Br model shows a steeper decline of TGM concentrations from the tropics to southern mid-latitudes. Only the Hg + Br model can reproduce the springtime depletion and summer rebound of TGM observed at polar sites; the snowpack component of GEOS-Chem suggests that 40% of Hg^{II} deposited to snow in the Arctic is transferred to the ocean and land reservoirs, amounting to a net deposition flux to the Arctic of 60 Mg a^{−1}. Summertime events of depleted Hg^{0} at Antarctic sites due to subsidence are much better simulated by
Pilot Wave model that includes creation and annihilation of particles
Sverdlov, Roman
2010-01-01
The purpose of this paper is to come up with a Pilot Wave model of quantum field theory that incorporates particle creation and annihilation without sacrificing determinism. This has been previously attempted in an article by the same author titled "Incorporating particle creation and annihilation in Pilot Wave model", in a much less satisfactory way. In this paper I would like to "clean up" some of the things. In particular, I would like to get rid of a very unnatural concept of "visibility" of particles, which makes the model much simpler. On the other hand, I would like to add a mechanism for decoherence, which was absent in the previous version.
Global atmospheric model for mercury including oxidation by bromine atoms
Directory of Open Access Journals (Sweden)
C. D. Holmes
2010-08-01
Full Text Available Global models of atmospheric mercury generally assume that OH and ozone are the main oxidants converting Hg^{0} to Hg^{II} and thus driving mercury deposition to ecosystems. However, thermodynamic considerations argue against the importance of these reactions. We demonstrate here the viability of atomic bromine (Br as an alternative Hg^{0} oxidant. We conduct a global 3-D simulation with the GEOS-Chem model assuming Br to be the sole Hg^{0} oxidant (Hg + Br model and compare to the previous version of the model with OH and ozone as the sole oxidants (Hg + OH/O_{3} model. We specify global 3-D Br concentration fields based on our best understanding of tropospheric and stratospheric Br chemistry. In both the Hg + Br and Hg + OH/O_{3} models, we add an aqueous photochemical reduction of Hg^{II} in cloud to impose a tropospheric lifetime for mercury of 6.5 months against deposition, as needed to reconcile observed total gaseous mercury (TGM concentrations with current estimates of anthropogenic emissions. This added reduction would not be necessary in the Hg + Br model if we adjusted the Br oxidation kinetics downward within their range of uncertainty. We find that the Hg + Br and Hg + OH/O_{3} models are equally capable of reproducing the spatial distribution of TGM and its seasonal cycle at northern mid-latitudes. The Hg + Br model shows a steeper decline of TGM concentrations from the tropics to southern mid-latitudes. Only the Hg + Br model can reproduce the springtime depletion and summer rebound of TGM observed at polar sites; the snowpack component of GEOS-Chem suggests that 40% of Hg^{II} deposited to snow in the Arctic is transferred to the ocean and land reservoirs, amounting to a net deposition flux of 60 Mg a^{−1}. Summertime events of depleted Hg^{0} at Antarctic sites due to subsidence are much better simulated by the Hg + Br model. Model
An Intracellular Calcium Oscillations Model Including Mitochondrial Calcium Cycling
Institute of Scientific and Technical Information of China (English)
SHI Xiao-Min; LIU Zeng-Rong
2005-01-01
@@ Calcium is a ubiquitous second messenger. Mitochondria contributes significantly to intracellular Ca2+ dynamics.The experiment of Kaftan et al. [J. Biol. Chem. 275(2000) 25465] demonstrated that inhibiting mitochondrial Ca2+ uptake can reduce the frequency of cytosolic Ca2+ concentration oscillations of gonadotropes. By considering the mitochondrial Ca2+ cycling we develop a three-variable model of intracellular Ca2+ oscillations based on the models of Atri et al. [Biophys. J. 65 (1993) 1727] and Falcke et al. [Biophys. J. 77 (1999) 37]. The model reproduces the fact that mitochondrial Ca2+ cycling increases the frequency of cytosolic Ca2+ oscillations, which accords with Kaftan's results. Moreover the model predicts that when the mitochondria overload with Ca2+, the cytosolic Ca2+ oscillations vanish, which may trigger apoptosis.
Cement-aggregate compatibility and structure property relationships including modelling
Energy Technology Data Exchange (ETDEWEB)
Jennings, H.M.; Xi, Y.
1993-07-15
The role of aggregate, and its interface with cement paste, is discussed with a view toward establishing models that relate structure to properties. Both short (nm) and long (mm) range structure must be considered. The short range structure of the interface depends not only on the physical distribution of the various phases, but also on moisture content and reactivity of aggregate. Changes that occur on drying, i.e. shrinkage, may alter the structure which, in turn, feeds back to alter further drying and shrinkage. The interaction is dynamic, even without further hydration of cement paste, and the dynamic characteristic must be considered in order to fully understand and model its contribution to properties. Microstructure and properties are two subjects which have been pursued somewhat separately. This review discusses both disciplines with a view toward finding common research goals in the future. Finally, comment is made on possible chemical reactions which may occur between aggregate and cement paste.
Including lateral interactions into microkinetic models of catalytic reactions
DEFF Research Database (Denmark)
Hellman, Anders; Honkala, Johanna Karoliina
2007-01-01
In many catalytic reactions lateral interactions between adsorbates are believed to have a strong influence on the reaction rates. We apply a microkinetic model to explore the effect of lateral interactions and how to efficiently take them into account in a simple catalytic reaction. Three differ...... different approximations are investigated: site, mean-field, and quasichemical approximations. The obtained results are compared to accurate Monte Carlo numbers. In the end, we apply the approximations to a real catalytic reaction, namely, ammonia synthesis....
Energy Technology Data Exchange (ETDEWEB)
Granderson, Jessica [Lawrence Berkeley National Laboratory (LBNL), Berkeley, CA (United States). Energy Technologies Area Div.; Price, Phillip N. [Lawrence Berkeley National Laboratory (LBNL), Berkeley, CA (United States). Energy Technologies Area Div.
2014-03-01
This paper documents the development and application of a general statistical methodology to assess the accuracy of baseline energy models, focusing on its application to Measurement and Verification (M&V) of whole-building energy savings. The methodology complements the principles addressed in resources such as ASHRAE Guideline 14 and the International Performance Measurement and Verification Protocol. It requires fitting a baseline model to data from a ``training period’’ and using the model to predict total electricity consumption during a subsequent ``prediction period.’’ We illustrate the methodology by evaluating five baseline models using data from 29 buildings. The training period and prediction period were varied, and model predictions of daily, weekly, and monthly energy consumption were compared to meter data to determine model accuracy. Several metrics were used to characterize the accuracy of the predictions, and in some cases the best-performing model as judged by one metric was not the best performer when judged by another metric.
Energy Technology Data Exchange (ETDEWEB)
Davis, R.; Fishman, D.; Frank, E. D.; Wigmosta, M. S.; Aden, A.; Coleman, A. M.; Pienkos, P. T.; Skaggs, R. J.; Venteris, E. R.; Wang, M. Q.
2012-06-01
The U.S. Department of Energy's Biomass Program has begun an initiative to obtain consistent quantitative metrics for algal biofuel production to establish an 'integrated baseline' by harmonizing and combining the Program's national resource assessment (RA), techno-economic analysis (TEA), and life-cycle analysis (LCA) models. The baseline attempts to represent a plausible near-term production scenario with freshwater microalgae growth, extraction of lipids, and conversion via hydroprocessing to produce a renewable diesel (RD) blendstock. Differences in the prior TEA and LCA models were reconciled (harmonized) and the RA model was used to prioritize and select the most favorable consortium of sites that supports production of 5 billion gallons per year of RD. Aligning the TEA and LCA models produced slightly higher costs and emissions compared to the pre-harmonized results. However, after then applying the productivities predicted by the RA model (13 g/m2/d on annual average vs. 25 g/m2/d in the original models), the integrated baseline resulted in markedly higher costs and emissions. The relationship between performance (cost and emissions) and either productivity or lipid fraction was found to be non-linear, and important implications on the TEA and LCA results were observed after introducing seasonal variability from the RA model. Increasing productivity and lipid fraction alone was insufficient to achieve cost and emission targets; however, combined with lower energy, less expensive alternative technology scenarios, emissions and costs were substantially reduced.
Comparison of Joint Modeling Approaches Including Eulerian Sliding Interfaces
Energy Technology Data Exchange (ETDEWEB)
Lomov, I; Antoun, T; Vorobiev, O
2009-12-16
Accurate representation of discontinuities such as joints and faults is a key ingredient for high fidelity modeling of shock propagation in geologic media. The following study was done to improve treatment of discontinuities (joints) in the Eulerian hydrocode GEODYN (Lomov and Liu 2005). Lagrangian methods with conforming meshes and explicit inclusion of joints in the geologic model are well suited for such an analysis. Unfortunately, current meshing tools are unable to automatically generate adequate hexahedral meshes for large numbers of irregular polyhedra. Another concern is that joint stiffness in such explicit computations requires significantly reduced time steps, with negative implications for both the efficiency and quality of the numerical solution. An alternative approach is to use non-conforming meshes and embed joint information into regular computational elements. However, once slip displacement on the joints become comparable to the zone size, Lagrangian (even non-conforming) meshes could suffer from tangling and decreased time step problems. The use of non-conforming meshes in an Eulerian solver may alleviate these difficulties and provide a viable numerical approach for modeling the effects of faults on the dynamic response of geologic materials. We studied shock propagation in jointed/faulted media using a Lagrangian and two Eulerian approaches. To investigate the accuracy of this joint treatment the GEODYN calculations have been compared with results from the Lagrangian code GEODYN-L which uses an explicit treatment of joints via common plane contact. We explore two approaches to joint treatment in the code, one for joints with finite thickness and the other for tight joints. In all cases the sliding interfaces are tracked explicitly without homogenization or blending the joint and block response into an average response. In general, rock joints will introduce an increase in normal compliance in addition to a reduction in shear strength. In the
Baek, Eun Kyeng; Ferron, John M
2013-03-01
Multilevel models (MLM) have been used as a method for analyzing multiple-baseline single-case data. However, some concerns can be raised because the models that have been used assume that the Level-1 error covariance matrix is the same for all participants. The purpose of this study was to extend the application of MLM of single-case data in order to accommodate across-participant variation in the Level-1 residual variance and autocorrelation. This more general model was then used in the analysis of single-case data sets to illustrate the method, to estimate the degree to which the autocorrelation and residual variances differed across participants, and to examine whether inferences about treatment effects were sensitive to whether or not the Level-1 error covariance matrix was allowed to vary across participants. The results from the analyses of five published studies showed that when the Level-1 error covariance matrix was allowed to vary across participants, some relatively large differences in autocorrelation estimates and error variance estimates emerged. The changes in modeling the variance structure did not change the conclusions about which fixed effects were statistically significant in most of the studies, but there was one exception. The fit indices did not consistently support selecting either the more complex covariance structure, which allowed the covariance parameters to vary across participants, or the simpler covariance structure. Given the uncertainty in model specification that may arise when modeling single-case data, researchers should consider conducting sensitivity analyses to examine the degree to which their conclusions are sensitive to modeling choices.
Neighboring extremal optimal control design including model mismatch errors
Energy Technology Data Exchange (ETDEWEB)
Kim, T.J. [Sandia National Labs., Albuquerque, NM (United States); Hull, D.G. [Texas Univ., Austin, TX (United States). Dept. of Aerospace Engineering and Engineering Mechanics
1994-11-01
The mismatch control technique that is used to simplify model equations of motion in order to determine analytic optimal control laws is extended using neighboring extremal theory. The first variation optimal control equations are linearized about the extremal path to account for perturbations in the initial state and the final constraint manifold. A numerical example demonstrates that the tuning procedure inherent in the mismatch control method increases the performance of the controls to the level of a numerically-determined piecewise-linear controller.
Double pendulum model for tennis stroke including a collision process
Youn, Sun-Hyun
2015-01-01
By means of adding a collision process between the ball and racket in double pendulum model, we analyzed the tennis stroke. It is possible that the speed of the rebound ball does not simply depend on the angular velocity of the racket, and higher angular velocity sometimes gives lower ball speed. We numerically showed that the proper time lagged racket rotation increases the speed of the rebound ball by 20%. We also showed that the elbow should move in order to add the angular velocity of the racket.
Hassan, Ehab; Morrison, P J; Horton, W
2016-01-01
Progress in understanding the coupling between plasma instabilities in the equatorial electrojet based on a unified fluid model is reported. A deeper understanding of the linear and nonlinear evolution and the coupling of the gradient-drift and Farley-Buneman instabilities is achieved by studying the e?ect of di?erent combinations of the density-gradient scale-lengths (Ln) and cross-?eld (E?B) drifts on the plasma turbulence. Mechanisms and channels of energy transfer are illucidated for these multiscale instabilities. Energy for the uni?ed model is examined, including the injected, conservative redistribution (between ?elds and scales), and ultimate dissipation. Various physical mechanisms involved in the energetics are categorized as sources, sinks, nonlinear transfer, and coupling to show that the system satisfies the fundamental law of energy Oonservation. The physics of the nonlinear transfer terms is studied to identify their roles in producing energy cascades { the transference of energy from the domin...
Modelling of Dual-Junction Solar Cells including Tunnel Junction
Directory of Open Access Journals (Sweden)
Abdelaziz Amine
2013-01-01
Full Text Available Monolithically stacked multijunction solar cells based on III–V semiconductors materials are the state-of-art of approach for high efficiency photovoltaic energy conversion, in particular for space applications. The individual subcells of the multi-junction structure are interconnected via tunnel diodes which must be optically transparent and connect the component cells with a minimum electrical resistance. The quality of these diodes determines the output performance of the solar cell. The purpose of this work is to contribute to the investigation of the tunnel electrical resistance of such a multi-junction cell through the analysis of the current-voltage (J-V characteristics under illumination. Our approach is based on an equivalent circuit model of a diode for each subcell. We examine the effect of tunnel resistance on the performance of a multi-junction cell using minimization of the least squares technique.
Human sperm chromatin stabilization: a proposed model including zinc bridges.
Björndahl, Lars; Kvist, Ulrik
2010-01-01
The primary focus of this review is to challenge the current concepts on sperm chromatin stability. The observations (i) that zinc depletion at ejaculation allows a rapid and total sperm chromatin decondensation without the addition of exogenous disulfide cleaving agents and (ii) that the human sperm chromatin contains one zinc for every protamine for every turn of the DNA helix suggest an alternative model for sperm chromatin structure may be plausible. An alternative model is therefore proposed, that the human spermatozoon could at ejaculation have a rapidly reversible zinc dependent chromatin stability: Zn(2+) stabilizes the structure and prevents the formation of excess disulfide bridges by a single mechanism, the formation of zinc bridges with protamine thiols of cysteine and potentially imidazole groups of histidine. Extraction of zinc enables two biologically totally different outcomes: immediate decondensation if chromatin fibers are concomitantly induced to repel (e.g. by phosphorylation in the ooplasm); otherwise freed thiols become committed into disulfide bridges creating a superstabilized chromatin. Spermatozoa in the zinc rich prostatic fluid (normally the first expelled ejaculate fraction) represent the physiological situation. Extraction of chromatin zinc can be accomplished by the seminal vesicular fluid. Collection of the ejaculate in one single container causes abnormal contact between spermatozoa and seminal vesicular fluid affecting the sperm chromatin stability. There are men in infertile couples with low content of sperm chromatin zinc due to loss of zinc during ejaculation and liquefaction. Tests for sperm DNA integrity may give false negative results due to decreased access for the assay to the DNA in superstabilized chromatin.
Global model including multistep ionizations in helium plasmas
Oh, Seung-Ju; Lee, Hyo-Chang; Chung, Chin-Wook
2016-12-01
Particle and power balance equations including stepwise ionizations are derived and solved in helium plasmas. In the balance equations, two metastable states (21S1 in singlet and 23S1 triplet) are considered and the followings are obtained. The plasma density linearly increases and the electron temperature is relatively in a constant value against the absorbed power. It is also found that the contribution to multi-step ionization with respect to the single-step ionization is in the range of 8%-23%, as the gas pressure increases from 10 mTorr to 100 mTorr. Compared to the results in the argon plasma, there is little variation in the collisional energy loss per electron-ion pair created (ɛc) with absorbed power and gas pressure due to the small collision cross section and higher inelastic collision threshold energy.
Modelization of a water tank including a PCM module
Energy Technology Data Exchange (ETDEWEB)
Ibanez, Manuel [Dept. de Medi Ambient i Ciencies del Sol, Universitat de Lleida, Rovira Roure 191, 25198 Lleida (Spain); Cabeza, Luisa F.; Sole, Cristian; Roca, Joan; Nogues, Miquel [Dept. d' Informatica i Eng. Industrial, Universitat de Lleida, Jaume II 69, 25001 Lleida (Spain)
2006-08-15
The reduction of CO{sub 2} emissions is a key component for today's governments. Therefore, implementation of more and more systems with renewable energies is necessary. Solar systems for single family houses or residential buildings need a big water tank that many times is not easy to locate. This paper studies the modelization of a new technology where PCM modules are implemented in domestic hot water tanks to reduce their size without reducing the energy stored. A new TRNSYS component, based in the already existing TYPE 60, was developed, called TYPE 60PCM. After tuning the new component with experimental results, two more experiences were developed to validate the simulation of a water tank with two cylindrical PCM modules using type 60PCM, the cooldown and reheating experiments. Concordance between experimental and simulated data was very good. Since the new TRNSYS component was developed to simulate full solar systems, comparison of experimental results from a pilot plant solar system with simulations were performed, and they confirmed that the type 60PCM is a powerful tool to evaluate the performance of PCM modules in water tanks. (author)
A new baseline of organic carbon stock in European agricultural soils using a modelling approach.
Lugato, Emanuele; Panagos, Panos; Bampa, Francesca; Jones, Arwyn; Montanarella, Luca
2014-01-01
Proposed European policy in the agricultural sector will place higher emphasis on soil organic carbon (SOC), both as an indicator of soil quality and as a means to offset CO2 emissions through soil carbon (C) sequestration. Despite detailed national SOC data sets in several European Union (EU) Member States, a consistent C stock estimation at EU scale remains problematic. Data are often not directly comparable, different methods have been used to obtain values (e.g. sampling, laboratory analysis) and access may be restricted. Therefore, any evolution of EU policies on C accounting and sequestration may be constrained by a lack of an accurate SOC estimation and the availability of tools to carry out scenario analysis, especially for agricultural soils. In this context, a comprehensive model platform was established at a pan-European scale (EU + Serbia, Bosnia and Herzegovina, Croatia, Montenegro, Albania, Former Yugoslav Republic of Macedonia and Norway) using the agro-ecosystem SOC model CENTURY. Almost 164 000 combinations of soil-climate-land use were computed, including the main arable crops, orchards and pasture. The model was implemented with the main management practices (e.g. irrigation, mineral and organic fertilization, tillage) derived from official statistics. The model results were tested against inventories from the European Environment and Observation Network (EIONET) and approximately 20 000 soil samples from the 2009 LUCAS survey, a monitoring project aiming at producing the first coherent, comprehensive and harmonized top-soil data set of the EU based on harmonized sampling and analytical methods. The CENTURY model estimation of the current 0-30 cm SOC stock of agricultural soils was 17.63 Gt; the model uncertainty estimation was below 36% in half of the NUTS2 regions considered. The model predicted an overall increase of this pool according to different climate-emission scenarios up to 2100, with C loss in the south and east of the area
Disease management projects and the Chronic Care Model in action: baseline qualitative research.
Walters, Bethany Hipple; Adams, Samantha A; Nieboer, Anna P; Bal, Roland
2012-05-11
Disease management programs, especially those based on the Chronic Care Model (CCM), are increasingly common in The Netherlands. While disease management programs have been well-researched quantitatively and economically, less qualitative research has been done. The overall aim of the study is to explore how disease management programs are implemented within primary care settings in The Netherlands; this paper focuses on the early development and implementation stages of five disease management programs in the primary care setting, based on interviews with project leadership teams. Eleven semi-structured interviews were conducted at the five selected sites with sixteen professionals interviewed; all project directors and managers were interviewed. The interviews focused on each project's chosen chronic illness (diabetes, eating disorders, COPD, multi-morbidity, CVRM) and project plan, barriers to development and implementation, the project leaders' action and reactions, as well as their roles and responsibilities, and disease management strategies. Analysis was inductive and interpretive, based on the content of the interviews. After analysis, the results of this research on disease management programs and the Chronic Care Model are viewed from a traveling technology framework. This analysis uncovered four themes that can be mapped to disease management and the Chronic Care Model: (1) changing the health care system, (2) patient-centered care, (3) technological systems and barriers, and (4) integrating projects into the larger system. Project leaders discussed the paths, both direct and indirect, for transforming the health care system to one that addresses chronic illness. Patient-centered care was highlighted as needed and a paradigm shift for many. Challenges with technological systems were pervasive. Project leaders managed the expenses of a traveling technology, including the social, financial, and administration involved. At the sites, project leaders served
Moeyaert, Mariola; Ugille, Maaike; Ferron, John M; Beretvas, S Natasha; Van den Noortgate, Wim
2013-06-01
In this study, we focus on a three-level meta-analysis for combining data from studies using multiple-baseline across-participants designs. A complicating factor in such designs is that results might be biased if the dependent variable is affected by not explicitly modeled external events, such as the illness of a teacher, an exciting class activity, or the presence of a foreign observer. In multiple-baseline designs, external effects can become apparent if they simultaneously have an effect on the outcome score(s) of the participants within a study. This study presents a method for adjusting the three-level model to external events and evaluates the appropriateness of the modified model. Therefore, we use a simulation study, and we illustrate the new approach with real data sets. The results indicate that ignoring an external event effect results in biased estimates of the treatment effects, especially when there is only a small number of studies and measurement occasions involved. The mean squared error, as well as the standard error and coverage proportion of the effect estimates, is improved with the modified model. Moreover, the adjusted model results in less biased variance estimates. If there is no external event effect, we find no differences in results between the modified and unmodified models.
General basin modeling for site suitability. Draft report 1. Baseline data
Energy Technology Data Exchange (ETDEWEB)
1979-04-01
This report summarizes work completed by Golder Associates under Task 2 - Site Suitability specifically for modeling of fluid flow and mass transport in sedimentary basins containing thick shale or salt. It also describes ongoing and future work on the above topic. The purpose of the study is to develop a general model for a nuclear waste repository situated in a deep sedimentary basin environment. The model will be used in conjunction with Golder's fluid flow and mass transport codes to study specific aspects of nuclide transport by groundwater flow.
Baseline groundwater model update for p-area groundwater operable unit, NBN
Energy Technology Data Exchange (ETDEWEB)
Ross, J. [Savannah River Site (SRS), Aiken, SC (United States); Amidon, M. [Savannah River Site (SRS), Aiken, SC (United States)
2015-09-01
This report documents the development of a numerical groundwater flow and transport model of the hydrogeologic system of the P-Area Reactor Groundwater Operable Unit at the Savannah River Site (SRS) (Figure 1-1). The P-Area model provides a tool to aid in understanding the hydrologic and geochemical processes that control the development and migration of the current tritium, tetrachloroethene (PCE), and trichloroethene (TCE) plumes in this region.
ADOP in closed form for a hierarchy of multi-frequency single-baseline GNSS models
Odijk, D.; Teunissen, P.J.G.
2008-01-01
Successful carrier phase ambiguity resolution is the key to high-precision positioning with Global Navigation Satellite Systems (GNSS). The ambiguity dilution of precision (ADOP) is a well-known scalar measure which can be used to infer the strength of the GNSS model for carrier phase ambiguity reso
Directory of Open Access Journals (Sweden)
Jelena Jovanović
2010-03-01
Full Text Available The research is oriented on improvement of environmental management system (EMS using BSC (Balanced Scorecard model that presents strategic model of measurem ents and improvement of organisational performance. The research will present approach of objectives and environmental management me trics involvement (proposed by literature review in conventional BSC in "Ad Barska plovi dba" organisation. Further we will test creation of ECO-BSC model based on business activities of non-profit organisations in order to improve envir onmental management system in parallel with other systems of management. Using this approach we may obtain 4 models of BSC that includ es elements of environmen tal management system for AD "Barska plovidba". Taking into acc ount that implementation and evaluation need long period of time in AD "Barska plovidba", the final choice will be based on 14598 (Information technology - Software product evaluation and ISO 9126 (Software engineering - Product quality using AHP method. Those standards are usually used for evaluation of quality software product and computer programs that serve in organisation as support and factors for development. So, AHP model will be bas ed on evolution criteria based on suggestion of ISO 9126 standards and types of evaluation from two evaluation teams. Members of team & will be experts in BSC and environmental management system that are not em ployed in AD "Barska Plovidba" organisation. The members of team 2 will be managers of AD "Barska Plovidba" organisation (including manage rs from environmental department. Merging results based on previously cr eated two AHP models, one can obtain the most appropriate BSC that includes elements of environmental management system. The chosen model will present at the same time suggestion for approach choice including ecological metrics in conventional BSC model for firm that has at least one ECO strategic orientation.
Modeling spatial patterns in soil arsenic to estimate natural baseline concentrations
Energy Technology Data Exchange (ETDEWEB)
Venteris, Erik R.; Basta, Nicolas T.; Bigham, Jerry M.; Rea, Ron
2014-05-09
ABSTRACT Arsenic in soil is an important public health concern. Toxicity guidelines and models based on laboratory studies (i.e., U.S. EPA’s Integrated Risk Information System) should consider natural soil As concentrations to avoid unnecessary remediation burdens on society. We used soil and stream sediment samples from the USGS National Geochemical Survey database to assess the spatial distribution of natural As in a 1.16E+5 km2 area. Samples were collected at 348 soil and 144 stream locations, providing approximately one sample for every 290 km2. Sample sites were selected to minimize the potential influence of anthropogenic inputs. Samples were processed using acid digestion of whole samples (concentrated HCl and ascorbic acid) and concentrations were measured using hydride-generation atomic absorption spectrometry. Soil As ranged from 2.0 to 45.6 mg kg-1. Geostatistical techniques were used to model and map the spatial variability of As. The mean and variance at unsampled locations were estimated using sequential Gaussian simulation. Five areas of elevated concentration (> the median of 10 mg kg-1) were identified and the relationships to geologic parent materials, glacial sedimentation patterns, and soil conditions interpreted. Our results showed As concentrations >10 mg kg-1 were common, and >20 mg kg-1 were not unusual for the central and west central portions of Ohio (USA). In contrast, concentrations <4 mg kg-1 were rare. Measured concentrations typically exceeded the soil As human generic screening levels of 0.39 mg/kg (1); the calculated value that corresponds to a cancer risk level of 1 in 1,000,000 for soil ingestion. Because the As content of Ohio soils is similar to many world soils, the USEPA generic soil screening level of 0.39 mg/kg is of little utility. A more useful and practical approach would be the uses of natural background levels. Regional soil As patterns based on geology and biogeochemistry and not political boundaries should be used
Hassan, Ehab; Hatch, D. R.; Morrison, P. J.; Horton, W.
2016-09-01
Progress in understanding the coupling between plasma instabilities in the equatorial electrojet based on a unified fluid model is reported. Simulations with parameters set to various ionospheric background conditions revealed properties of the gradient-drift and Farley-Buneman instabilities. Notably, sharper density gradients increase linear growth rates at all scales, whereas variations in cross-field E × B drift velocity only affect small-scale instabilities. A formalism defining turbulent fluctuation energy for the system is introduced, and the turbulence is analyzed within this framework. This exercise serves as a useful verification test of the numerical simulations and also elucidates the physics underlying the ionospheric turbulence. Various physical mechanisms involved in the energetics are categorized as sources, sinks, nonlinear transfer, and cross-field coupling. The physics of the nonlinear transfer terms is studied to identify their roles in producing energy cascades, which explain the generation of small-scale structures that are stable in the linear regime. The theory of two-step energy cascading to generate the 3 m plasma irregularities in the equatorial electrojet is verified for the first time in the fluid regime. In addition, the nonlinearity of the system allows the possibility of an inverse energy cascade, potentially responsible for generating large-scale plasma structures at the top of the electrojet as found in different rocket and radar observations.
Energy Technology Data Exchange (ETDEWEB)
Coughlin, Katie; Piette, Mary Ann; Goldman, Charles; Kiliccote,Sila
2008-01-01
Both Federal and California state policymakers areincreasingly interested in developing more standardized and consistentapproaches to estimate and verify the load impacts of demand responseprograms and dynamic pricing tariffs. This study describes a statisticalanalysis of the performance of different models used to calculate thebaseline electric load for commercial buildings participating in ademand-response (DR) program, with emphasis onthe importance of weathereffects. During a DR event, a variety of adjustments may be made tobuilding operation, with the goal of reducing the building peak electricload. In order to determine the actual peak load reduction, an estimateof what the load would have been on the day of the event without any DRactions is needed. This baseline load profile (BLP) is key to accuratelyassessing the load impacts from event-based DR programs and may alsoimpact payment settlements for certain types of DR programs. We testedseven baseline models on a sample of 33 buildings located in California.These models can be loosely categorized into two groups: (1) averagingmethods, which use some linear combination of hourly load values fromprevious days to predict the load on the event, and (2) explicit weathermodels, which use a formula based on local hourly temperature to predictthe load. The models were tested both with and without morningadjustments, which use data from the day of the event to adjust theestimated BLP up or down.Key findings from this study are: - The accuracyof the BLP model currently used by California utilities to estimate loadreductions in several DR programs (i.e., hourly usage in highest 3 out of10 previous days) could be improved substantially if a morning adjustmentfactor were applied for weather-sensitive commercial and institutionalbuildings. - Applying a morning adjustment factor significantly reducesthe bias and improves the accuracy of all BLP models examined in oursample of buildings. - For buildings with low load
2012-09-01
ATMOSPHERIC MODELS INCLUDING ENSEMBLE METHODS Scott E. Miller Lieutenant Commander, United States Navy B.S., University of South Carolina, 2000 B.S...Typical gas turbine fuel consumption curve and relationship to sea state .......51 Figure 16. DDG 58 speed reduction curves for bow seas...Day Time Group ECDIS-N Electronic Chart Display and Information System – Navy ECMWF European Center for Medium Range Weather Forecasts EFAS
Hydropower Baseline Cost Modeling
Energy Technology Data Exchange (ETDEWEB)
O' Connor, Patrick W. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Zhang, Qin Fen [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); DeNeale, Scott T. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Chalise, Dol Raj [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Centurion, Emma E. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)
2015-01-01
Recent resource assessments conducted by the United States Department of Energy have identified significant opportunities for expanding hydropower generation through the addition of power to non-powered dams and on undeveloped stream-reaches. Additional interest exists in the powering of existing water resource infrastructure such as conduits and canals, upgrading and expanding existing hydropower facilities, and the construction new pumped storage hydropower. Understanding the potential future role of these hydropower resources in the nation’s energy system requires an assessment of the environmental and techno-economic issues associated with expanding hydropower generation. To facilitate these assessments, this report seeks to fill the current gaps in publically available hydropower cost-estimating tools that can support the national-scale evaluation of hydropower resources.
Benjamin, Stan; Sun, Shan; Grell, Georg; Green, Benjamin; Bleck, Rainer; Li, Haiqin
2017-04-01
Extreme events for subseasonal duration have been linked to multi-week processes related to onset, duration, and cessation of blocking events or, more generally, quasi-stationary waves. Results will be shown from different sets of 32-day prediction experiments (3200 runs each) over a 16-year period for earth system processes key for subseasonal prediction for different resolution, numerics, and physics using the FIM-HYCOM coupled model. The coupled atmosphere (FIM) and ocean (HYCOM) modeling system is a relatively new coupled atmosphere-ocean model developed for subseasonal to seasonal prediction (Green et al. 2017 Mon.Wea.Rev. accepted, Bleck et al 2015 Mon. Wea. Rev.). Both component models operate on a common icosahedral horizontal grid and use an adaptive hybrid vertical coordinate (sigma-isentropic in FIM and sigma-isopycnic in HYCOM). FIM-HYCOM has been used to conduct 16 years of subseasonal retrospective forecasts following the NOAA Subseasonal (SubX) NMME protocol (32-day forward integrations), run with 4 ensemble members per week. Results from this multi-year FIM-HYCOM hindcast include successful forecasts out to 14-20 days for stratospheric warming events (from archived 10 hPa fields), improved MJO predictability (Green et al. 2017) using the Grell-Freitas (2014, ACP) scale-aware cumulus scheme instead of the Simplified Arakawa-Schubert scheme, and little sensitivity to resolution for blocking frequency. Forecast skill of metrics from FIM-HYCOM including 500 hPa heights and MJO index is at least comparable to that of the operational Climate Forecast System (CFSv2) used by the National Centers for Environmental Prediction. Subseasonal skill is improved with a limited multi-model (FIM-HYCOM and CFSv2), consistent with previous seasonal multi-model ensemble results. Ongoing work will also be reported on for adding inline aerosol/chemistry treatment to the coupled FIM-HYCOM model and for advanced approaches to subgrid-scale clouds to address regional biases
Sawada, Norie; Iwasaki, Motoki; Ohashi, Kayo; Tsugane, Shoichiro
2016-01-01
Background Some recent molecular epidemiology studies of the effects of genetic and environmental factors on human health have required the enrollment of more than 100 000 participants and the involvement of regional study offices across the country. Although regional study office investigators play a critical role in these studies, including the acquisition of funds, this role is rarely discussed. Methods We first differentiated the functions of the regional and central study offices. We then investigated the minimum number of items required and approximate cost of a molecular epidemiology study enrolling 7400 participants from a model region with a population of 100 000 for a 4-year baseline survey using a standard protocol developed based on the protocol of Japan Public Health Center-based Prospective Study for the Next Generation. Results The functions of the regional study office were identified, and individual expenses were itemized. The total cost of the 4-year baseline survey was 153 million yen, excluding consumption tax. Accounting difficulties in conducting the survey were clarified. Conclusions We investigated a standardized example of the tasks and total actual costs of a regional study office. Our approach is easy to utilize and will help improve the management of regional study offices in future molecular epidemiology studies. PMID:27001116
Hanford Site technical baseline database
Energy Technology Data Exchange (ETDEWEB)
Porter, P.E.
1996-09-30
This document includes a cassette tape that contains the Hanford specific files that make up the Hanford Site Technical Baseline Database as of September 30, 1996. The cassette tape also includes the delta files that dellinate the differences between this revision and revision 4 (May 10, 1996) of the Hanford Site Technical Baseline Database.
Hanford Site technical baseline database
Energy Technology Data Exchange (ETDEWEB)
Porter, P.E., Westinghouse Hanford
1996-05-10
This document includes a cassette tape that contains the Hanford specific files that make up the Hanford Site Technical Baseline Database as of May 10, 1996. The cassette tape also includes the delta files that delineate the differences between this revision and revision 3 (April 10, 1996) of the Hanford Site Technical Baseline Database.
Energy Technology Data Exchange (ETDEWEB)
Defraene, Gilles, E-mail: gilles.defraene@uzleuven.be [Radiation Oncology Department, University Hospitals Leuven, Leuven (Belgium); Van den Bergh, Laura [Radiation Oncology Department, University Hospitals Leuven, Leuven (Belgium); Al-Mamgani, Abrahim [Department of Radiation Oncology, Erasmus Medical Center - Daniel den Hoed Cancer Center, Rotterdam (Netherlands); Haustermans, Karin [Radiation Oncology Department, University Hospitals Leuven, Leuven (Belgium); Heemsbergen, Wilma [Netherlands Cancer Institute - Antoni van Leeuwenhoek Hospital, Amsterdam (Netherlands); Van den Heuvel, Frank [Radiation Oncology Department, University Hospitals Leuven, Leuven (Belgium); Lebesque, Joos V. [Netherlands Cancer Institute - Antoni van Leeuwenhoek Hospital, Amsterdam (Netherlands)
2012-03-01
Purpose: To study the impact of clinical predisposing factors on rectal normal tissue complication probability modeling using the updated results of the Dutch prostate dose-escalation trial. Methods and Materials: Toxicity data of 512 patients (conformally treated to 68 Gy [n = 284] and 78 Gy [n = 228]) with complete follow-up at 3 years after radiotherapy were studied. Scored end points were rectal bleeding, high stool frequency, and fecal incontinence. Two traditional dose-based models (Lyman-Kutcher-Burman (LKB) and Relative Seriality (RS) and a logistic model were fitted using a maximum likelihood approach. Furthermore, these model fits were improved by including the most significant clinical factors. The area under the receiver operating characteristic curve (AUC) was used to compare the discriminating ability of all fits. Results: Including clinical factors significantly increased the predictive power of the models for all end points. In the optimal LKB, RS, and logistic models for rectal bleeding and fecal incontinence, the first significant (p = 0.011-0.013) clinical factor was 'previous abdominal surgery.' As second significant (p = 0.012-0.016) factor, 'cardiac history' was included in all three rectal bleeding fits, whereas including 'diabetes' was significant (p = 0.039-0.048) in fecal incontinence modeling but only in the LKB and logistic models. High stool frequency fits only benefitted significantly (p = 0.003-0.006) from the inclusion of the baseline toxicity score. For all models rectal bleeding fits had the highest AUC (0.77) where it was 0.63 and 0.68 for high stool frequency and fecal incontinence, respectively. LKB and logistic model fits resulted in similar values for the volume parameter. The steepness parameter was somewhat higher in the logistic model, also resulting in a slightly lower D{sub 50}. Anal wall DVHs were used for fecal incontinence, whereas anorectal wall dose best described the other two endpoints
Energy Technology Data Exchange (ETDEWEB)
Gray, D.; Tomlinson, G.C. (Mitre Corp., McLean, VA (USA). Civil Systems Div.)
1990-10-01
This report documents the development of an integrated indirect liquefaction system model, which processes input coal to refined liquid products, and the model's application in the analysis of a baseline case. The baseline case uses Shell gasification of coal followed by gas cleaning to produce a clean synthesis gas for slurry-phase Fischer-Tropsch synthesis. The raw liquid products are refined to produce gasoline and diesel. Costs of liquid products have been estimated for the baseline plant. The model also alloys many sensitivity studies to be performed so that the economic impacts of research and development advances can be quantified. When used in this manner, the model can provide research guidance for future indirect liquefaction studies. 18 refs., 12 figs., 12 tabs.
Caruana, Emmanuel; Chevret, Sylvie; Resche-Rigon, Matthieu; Pirracchio, Romain
2015-12-01
The propensity score (PS) is a balancing score. Following PS matching, balance checking usually relies on estimating separately the standardized absolute mean difference for each baseline characteristic. The average standardized absolute mean difference and the Mahalanobis distances have been proposed to summarize the information across the covariates. However, they might be minimized when nondesirable variables such as instrumental variables (IV) are included in the PS model. We propose a new weighted summary balance measure that takes into account, for each covariate, its strength of association with the outcome. This new measure was evaluated using a simulation study to assess whether minimization of the measure coincided with minimally biased estimates. All measures were then applied to a real data set from an observational cohort study. Contrarily to the other measures, our proposal was minimized when including the confounders, which coincided with minimal bias and mean squared error, but increased when including an IV in the PS model. Similar findings were observed in the real data set. A balance measure taking into account the strength of association between the covariates and the outcome may be helpful to identify the most parsimonious PS model. Copyright © 2015 Elsevier Inc. All rights reserved.
Nguyen, Tien M.; Guillen, Andy T.
2017-05-01
This paper describes static Bayesian game models with "Pure" and "Mixed" games for the development of an optimum Program and Technical Baseline (PTB) solution for affordable acquisition of future space systems. The paper discusses System Engineering (SE) frameworks and analytical and simulation modeling approaches for developing the optimum PTB solutions from both the government and contractor perspectives.
Nafishoh, Qoriatun; Riqqi, Akhmad; Meilano, Irwan
2017-07-01
The Bandung Basin area has highly susceptible to the natural disasters. Therefore, resilience measurement is useful to find out the capacity of an area in the facing of a natural disaster. Natural disaster resilience can be measured using BRIC (Baseline Resilience Indicators for Communities) model. This model comprises several indicators; includes social, economic, community, institution, infrastructure, and the environment. This research tries to measure resilience to the natural disasters with still focusing on infrastructure resilience measurement by spatial modeling and analyzed the dominant driving factor that contributes to this resilience trend. We generated a spatial modeling by applying a spatial analysis to the infrastructure objects. The infrastructure objects consist of the road, school, and health facilities. Those objects will be given some radius levels that indicate the resilience level by using buffer processing. An area closest to those objects will have high resilience and contrarily. Our result showed that almost all city areas (Bandung and Cimahi City) have high resilience because they have many infrastructure objects. But contrarily with the district areas which are still contained many patterns of low and moderate resilience level. The dominant driving factor of infrastructure resilience in this research area is a road. The areas which are closest to the road have high resilience and farther away from the road will have low resilience.
Energy Technology Data Exchange (ETDEWEB)
Bergami, L.; Gaunaa, M.
2012-02-15
The report presents the ATEFlap aerodynamic model, which computes the unsteady lift, drag and moment on a 2D airfoil section equipped with Adaptive Trailing Edge Flap. The model captures the unsteady response related to the effects of the vorticity shed into the wake, and the dynamics of flow separation a thin-airfoil potential flow model is merged with a dynamic stall model of the Beddoes-Leishmann type. The inputs required by the model are steady data for lift, drag, and moment coefficients as function of angle of attack and flap deflection. Further steady data used by the Beddoes- Leishmann dynamic stall model are computed in an external preprocessor application, which gives the user the possibility to verify, and eventually correct, the steady data passed to the aerodynamic model. The ATEFlap aerodynamic model is integrated in the aeroelastic simulation tool HAWC2, thus al- lowing to simulate the response of a wind turbine with trailing edge flaps on the rotor. The algorithms used by the preprocessor, and by aerodynamic model are presented, and modifications to previous implementations of the aerodynamic model are briefly discussed. The performance and the validity of the model are verified by comparing the dynamic response computed by the ATEFlap with solutions from CFD simulations. (Author)
Importance of global aerosol modeling including secondary organic aerosol formed from monoterpene
Goto, Daisuke; Takemura, Toshihiko; Nakajima, Teruyuki
2008-01-01
A global three-dimensional aerosol transport-radiation model, coupled to an atmospheric general circulation model (AGCM), has been extended to improve the model process for organic aerosols, particularly secondary organic aerosols (SOA), and to estimate SOA contributions to direct and indirect radiative effects. Because the SOA formation process is complicated and unknown, the results in different model simulations include large differences. In this work, we simulate SOA production assuming v...
MODEL ANALYSIS AND PARAMETER EXTRACTION FOR MOS CAPACITOR INCLUDING QUANTUM MECHANICAL EFFECTS
Institute of Scientific and Technical Information of China (English)
Hai-yan Jiang; Ping-wen Zhang
2006-01-01
The high frequency CV curves of MOS capacitor have been studied. It is shown that semiclassical model is a good approximation to quantum model and approaches to classical model when the oxide layer is thick. This conclusion provides us an efficient (semiclassical) model including quantum mechanical effects to do parameter extraction for ultrathi noxide device. Here the effective extracting strategy is designed and numerical experiments demonstrate the validity of the strategy.
A finite element model of the face including an orthotropic skin model under in vivo tension.
Flynn, Cormac; Stavness, Ian; Lloyd, John; Fels, Sidney
2015-01-01
Computer models of the human face have the potential to be used as powerful tools in surgery simulation and animation development applications. While existing models accurately represent various anatomical features of the face, the representation of the skin and soft tissues is very simplified. A computer model of the face is proposed in which the skin is represented by an orthotropic hyperelastic constitutive model. The in vivo tension inherent in skin is also represented in the model. The model was tested by simulating several facial expressions by activating appropriate orofacial and jaw muscles. Previous experiments calculated the change in orientation of the long axis of elliptical wounds on patients' faces for wide opening of the mouth and an open-mouth smile (both 30(o)). These results were compared with the average change of maximum principal stress direction in the skin calculated in the face model for wide opening of the mouth (18(o)) and an open-mouth smile (25(o)). The displacements of landmarks on the face for four facial expressions were compared with experimental measurements in the literature. The corner of the mouth in the model experienced the largest displacement for each facial expression (∼11-14 mm). The simulated landmark displacements were within a standard deviation of the measured displacements. Increasing the skin stiffness and skin tension generally resulted in a reduction in landmark displacements upon facial expression.
Cross, Paul C.; Maichak, Eric J.; Rogerson, Jared D.; Irvine, Kathryn M.; Jones, Jennifer D; Heisey, Dennis M.; Edwards, William H.; Scurlock, Brandon M.
2015-01-01
Understanding the seasonal timing of disease transmission can lead to more effective control strategies, but the seasonality of transmission is often unknown for pathogens transmitted directly. We inserted vaginal implant transmitters (VITs) in 575 elk (Cervus elaphus canadensis) from 2006 to 2014 to assess when reproductive failures (i.e., abortions or still births) occur, which is the primary transmission route of Brucella abortus, the causative agent of brucellosis in the Greater Yellowstone Ecosystem. Using a survival analysis framework, we developed a Bayesian hierarchical model that simultaneously estimated the total baseline hazard of a reproductive event as well as its 2 mutually exclusive parts (abortions or live births). Approximately, 16% (95% CI = 0.10, 0.23) of the pregnant seropositive elk had reproductive failures, whereas 2% (95% CI = 0.01, 0.04) of the seronegative elk had probable abortions. Reproductive failures could have occurred as early as 13 February and as late as 10 July, peaking from March through May. Model results suggest that less than 5% of likely abortions occurred after 6 June each year and abortions were approximately 5 times more likely in March, April, or May compared to February or June. In western Wyoming, supplemental feeding of elk begins in December and ends during the peak of elk abortions and brucellosis transmission (i.e., Mar and Apr). Years with more snow may enhance elk-to-elk transmission on supplemental feeding areas because elk are artificially aggregated for the majority of the transmission season. Elk-to-cattle transmission will depend on the transmission period relative to the end of the supplemental feeding season, elk seroprevalence, population size, and the amount of commingling. Our statistical approach allowed us to estimate the probability density function of different event types over time, which may be applicable to other cause-specific survival analyses. It is often challenging to assess the
Hot DA white dwarf model atmosphere calculations: Including improved Ni PI cross sections
Preval, S P; Badnell, N R; Hubeny, I; Holberg, J B
2016-01-01
To calculate realistic models of objects with Ni in their atmospheres, accurate atomic data for the relevant ionization stages needs to be included in model atmosphere calculations. In the context of white dwarf stars, we investigate the effect of changing the Ni {\\sc iv}-{\\sc vi} bound-bound and bound-free atomic data has on model atmosphere calculations. Models including PICS calculated with {\\sc autostructure} show significant flux attenuation of up to $\\sim 80$\\% shortward of 180\\AA\\, in the EUV region compared to a model using hydrogenic PICS. Comparatively, models including a larger set of Ni transitions left the EUV, UV, and optical continua unaffected. We use models calculated with permutations of this atomic data to test for potential changes to measured metal abundances of the hot DA white dwarf G191-B2B. Models including {\\sc autostructure} PICS were found to change the abundances of N and O by as much as $\\sim 22$\\% compared to models using hydrogenic PICS, but heavier species were relatively unaf...
Mathematical Model of Thyristor Inverter Including a Series-parallel Resonant Circuit
Directory of Open Access Journals (Sweden)
Miroslaw Luft
2008-01-01
Full Text Available The article presents a mathematical model of thyristor inverter including a series-parallel resonant circuit with theaid of state variable method. Maple procedures are used to compute current and voltage waveforms in the inverter.
Dunne, John P.; John, Jasmin G.; Adcroft, Alistair J.; Griffies, Stephen M.; Hallberg, Robert W.; Shevalikova, Elena; Stouffer, Ronald J.; Cooke, William; Dunne, Krista A.; Harrison, Matthew J.; Krasting, John P.; Malyshev, Sergey L.; Milly, P.C.D.; Phillipps, Peter J.; Sentman, Lori A.; Samuels, Bonita L.; Spelman, Michael J.; Winton, Michael; Wittenberg, Andrew T.; Zadeh, Niki
2012-01-01
We describe the physical climate formulation and simulation characteristics of two new global coupled carbon-climate Earth System Models, ESM2M and ESM2G. These models demonstrate similar climate fidelity as the Geophysical Fluid Dynamics Laboratory's previous CM2.1 climate model while incorporating explicit and consistent carbon dynamics. The two models differ exclusively in the physical ocean component; ESM2M uses Modular Ocean Model version 4.1 with vertical pressure layers while ESM2G uses Generalized Ocean Layer Dynamics with a bulk mixed layer and interior isopycnal layers. Differences in the ocean mean state include the thermocline depth being relatively deep in ESM2M and relatively shallow in ESM2G compared to observations. The crucial role of ocean dynamics on climate variability is highlighted in the El Niño-Southern Oscillation being overly strong in ESM2M and overly weak ESM2G relative to observations. Thus, while ESM2G might better represent climate changes relating to: total heat content variability given its lack of long term drift, gyre circulation and ventilation in the North Pacific, tropical Atlantic and Indian Oceans, and depth structure in the overturning and abyssal flows, ESM2M might better represent climate changes relating to: surface circulation given its superior surface temperature, salinity and height patterns, tropical Pacific circulation and variability, and Southern Ocean dynamics. Our overall assessment is that neither model is fundamentally superior to the other, and that both models achieve sufficient fidelity to allow meaningful climate and earth system modeling applications. This affords us the ability to assess the role of ocean configuration on earth system interactions in the context of two state-of-the-art coupled carbon-climate models.
The TDAQ Baseline Architecture
Wickens, F J
The Trigger-DAQ community is currently busy preparing material for the DAQ, HLT and DCS TDR. Over the last few weeks a very important step has been a series of meetings to complete agreement on the baseline architecture. An overview of the architecture indicating some of the main parameters is shown in figure 1. As reported at the ATLAS Plenary during the February ATLAS week, the main area where the baseline had not yet been agreed was around the Read-Out System (ROS) and details in the DataFlow. The agreed architecture has: Read-Out Links (ROLs) from the RODs using S-Link; Read-Out Buffers (ROB) sited near the RODs, mounted in a chassis - today assumed to be a PC, using PCI bus at least for configuration, control and monitoring. The baseline assumes data aggregation, in the ROB and/or at the output (which could either be over a bus or in the network). Optimization of the data aggregation will be made in the coming months, but the current model has each ROB card receiving input from 4 ROLs, and 3 such c...
A Verilog-A large signal model for InP DHBT including thermal effects
Yuxia, Shi; Zhi, Jin; Zhijian, Pan; Yongbo, Su; Yuxiong, Cao; Yan, Wang
2013-06-01
A large signal model for InP/InGaAs double heterojunction bipolar transistors including thermal effects has been reported, which demonstrated good agreements of simulations with measurements. On the basis of the previous model in which the double heterojunction effect, current blocking effect and high current effect in current expression are considered, the effect of bandgap narrowing with temperature has been considered in transport current while a formula for model parameters as a function of temperature has been developed. This model is implemented by Verilog-A and embedded in ADS. The proposed model is verified with DC and large signal measurements.
Modelling Mediterranean agro-ecosystems by including agricultural trees in the LPJmL model
Fader, M.; von Bloh, W.; Shi, S.; Bondeau, A.; Cramer, W.
2015-11-01
In the Mediterranean region, climate and land use change are expected to impact on natural and agricultural ecosystems by warming, reduced rainfall, direct degradation of ecosystems and biodiversity loss. Human population growth and socioeconomic changes, notably on the eastern and southern shores, will require increases in food production and put additional pressure on agro-ecosystems and water resources. Coping with these challenges requires informed decisions that, in turn, require assessments by means of a comprehensive agro-ecosystem and hydrological model. This study presents the inclusion of 10 Mediterranean agricultural plants, mainly perennial crops, in an agro-ecosystem model (Lund-Potsdam-Jena managed Land - LPJmL): nut trees, date palms, citrus trees, orchards, olive trees, grapes, cotton, potatoes, vegetables and fodder grasses. The model was successfully tested in three model outputs: agricultural yields, irrigation requirements and soil carbon density. With the development presented in this study, LPJmL is now able to simulate in good detail and mechanistically the functioning of Mediterranean agriculture with a comprehensive representation of ecophysiological processes for all vegetation types (natural and agricultural) and in a consistent framework that produces estimates of carbon, agricultural and hydrological variables for the entire Mediterranean basin. This development paves the way for further model extensions aiming at the representation of alternative agro-ecosystems (e.g. agroforestry), and opens the door for a large number of applications in the Mediterranean region, for example assessments of the consequences of land use transitions, the influence of management practices and climate change impacts.
Modelling Mediterranean agro-ecosystems by including agricultural trees in the LPJmL model
Directory of Open Access Journals (Sweden)
M. Fader
2015-06-01
Full Text Available Climate and land use change in the Mediterranean region is expected to affect natural and agricultural ecosystems by decreases in precipitation, increases in temperature as well as biodiversity loss and anthropogenic degradation of natural resources. Demographic growth in the Eastern and Southern shores will require increases in food production and put additional pressure on agro-ecosystems and water resources. Coping with these challenges requires informed decisions that, in turn, require assessments by means of a comprehensive agro-ecosystem and hydrological model. This study presents the inclusion of 10 Mediterranean agricultural plants, mainly perennial crops, in an agro-ecosystem model (LPJmL: nut trees, date palms, citrus trees, orchards, olive trees, grapes, cotton, potatoes, vegetables and fodder grasses. The model was successfully tested in three model outputs: agricultural yields, irrigation requirements and soil carbon density. With the development presented in this study, LPJmL is now able to simulate in good detail and mechanistically the functioning of Mediterranean agriculture with a comprehensive representation of ecophysiological processes for all vegetation types (natural and agricultural and in a consistent framework that produces estimates of carbon, agricultural and hydrological variables for the entire Mediterranean basin. This development pave the way for further model extensions aiming at the representation of alternative agro-ecosystems (e.g. agroforestry, and opens the door for a large number of applications in the Mediterranean region, for example assessments on the consequences of land use transitions, the influence of management practices and climate change impacts.
Numerical Acoustic Models Including Viscous and Thermal losses: Review of Existing and New Methods
DEFF Research Database (Denmark)
Andersen, Peter Risby; Cutanda Henriquez, Vicente; Aage, Niels
2017-01-01
This work presents an updated overview of numerical methods including acoustic viscous and thermal losses. Numerical modelling of viscothermal losses has gradually become more important due to the general trend of making acoustic devices smaller. Not including viscothermal acoustic losses in such...
Zhang, Huiyan; Wang, Yun; Shao, Shanshan; Xiao, Rui
2016-11-01
Lignin is the most difficult to be converted and most easy coking component in biomass catalytic pyrolysis to high-value liquid fuels and chemicals. Catalytic conversion of guaiacol as a lignin model compound was conducted in a fixed-bed reactor over ZSM-5 to investigate its conversion and coking behaviors. The effects of temperature, weight hourly space velocity (WHSV) and partial pressure on product distribution were studied. The results show the maximum aromatic carbon yield of 28.55% was obtained at temperature of 650 °C, WHSV of 8 h‑1 and partial pressure of 2.38 kPa, while the coke carbon yield was 19.55%. The reaction pathway was speculated to be removing methoxy group to form phenols with further aromatization to form aromatics. The amount of coke increased with increasing reaction time. The surface area and acidity of catalysts declined as coke formed on the acid sites and blocked the pore channels, which led to the decrease of aromatic yields. Finally, a kinetic model of guaiacol catalytic conversion considering coke deposition was built based on the above reaction pathway to properly predict product distribution. The experimental and model predicting data agreed well. The correlation coefficient of all equations were all higher than 0.90.
Including operational data in QMRA model: development and impact of model inputs.
Jaidi, Kenza; Barbeau, Benoit; Carrière, Annie; Desjardins, Raymond; Prévost, Michèle
2009-03-01
A Monte Carlo model, based on the Quantitative Microbial Risk Analysis approach (QMRA), has been developed to assess the relative risks of infection associated with the presence of Cryptosporidium and Giardia in drinking water. The impact of various approaches for modelling the initial parameters of the model on the final risk assessments is evaluated. The Monte Carlo simulations that we performed showed that the occurrence of parasites in raw water was best described by a mixed distribution: log-Normal for concentrations > detection limit (DL), and a uniform distribution for concentrations risks significantly. The mean annual risks for conventional treatment are: 1.97E-03 (removal credit adjusted by log parasite = log spores), 1.58E-05 (log parasite = 1.7 x log spores) or 9.33E-03 (regulatory credits based on the turbidity measurement in filtered water). Using full scale validated SCADA data, the simplified calculation of CT performed at the plant was shown to largely underestimate the risk relative to a more detailed CT calculation, which takes into consideration the downtime and system failure events identified at the plant (1.46E-03 vs. 3.93E-02 for the mean risk).
Cooney, Gregory; Jamieson, Matthew; Marriott, Joe; Bergerson, Joule; Brandt, Adam; Skone, Timothy J
2017-01-17
The National Energy Technology Laboratory produced a well-to-wheels (WTW) life cycle greenhouse gas analysis of petroleum-based fuels consumed in the U.S. in 2005, known as the NETL 2005 Petroleum Baseline. This study uses a set of engineering-based, open-source models combined with publicly available data to calculate baseline results for 2014. An increase between the 2005 baseline and the 2014 results presented here (e.g., 92.4 vs 96.2 g CO2e/MJ gasoline, + 4.1%) are due to changes both in modeling platform and in the U.S. petroleum sector. An updated result for 2005 was calculated to minimize the effect of the change in modeling platform, and emissions for gasoline in 2014 were about 2% lower than in 2005 (98.1 vs 96.2 g CO2e/MJ gasoline). The same methods were utilized to forecast emissions from fuels out to 2040, indicating maximum changes from the 2014 gasoline result between +2.1% and -1.4%. The changing baseline values lead to potential compliance challenges with frameworks such as the Energy Independence and Security Act (EISA) Section 526, which states that Federal agencies should not purchase alternative fuels unless their life cycle GHG emissions are less than those of conventionally produced, petroleum-derived fuels.
Institute of Scientific and Technical Information of China (English)
何雪松; 王旭永; 冯正进; 章志新; 杨钦廉
2003-01-01
A nonlinear mathematical model of the injection molding process for electrohydraulic servo injection molding machine (IMM) is developed.It was found necessary to consider the characteristics of asymmetric cylinder for electrohydraulic servo IMM.The model is based on the dynamics of the machine including servo valve,asymmetric cylinder and screw,and the non-Newtonian flow behavior of polymer melt in injection molding is also considered.The performance of the model was evaluated based on novel approach of molding - injection and compress molding,and the results of simulation and experimental data demonstrate the effectiveness of the model.
a Better Description of Liquid Jet Breakup Using a Spatial Model Including Viscous Effects.
Hammerschlag, William Brian
Theoretical models describing the operation and disintegration of a liquid jet are often based on an approximate solution of an inviscid jet in the temporal frame of reference. These models provide only a fair first order prediction of growth rate and breakoff length, and are based solely on a surface tension induced instability. A spatial model yielding jet growth rate and including both jet and surrounding atmosphere viscosity and density is now developed. This model is seen to reproduce all the features and limitations of the Weber viscous jet theory. When tested against experiments of water, water and glycerol mixes and binary eutectic tin/lead solder, only fair agreement is observed.
Directory of Open Access Journals (Sweden)
Ahmet Bozkurt
2014-01-01
Full Text Available Autologous nerve transplantation (ANT is the clinical gold standard for the reconstruction of peripheral nerve defects. A large number of bioengineered nerve guides have been tested under laboratory conditions as an alternative to the ANT. The step from experimental studies to the implementation of the device in the clinical setting is often substantial and the outcome is unpredictable. This is mainly linked to the heterogeneity of clinical peripheral nerve injuries, which is very different from standardized animal studies. In search of a reproducible human model for the implantation of bioengineered nerve guides, we propose the reconstruction of sural nerve defects after routine nerve biopsy as a first or baseline study. Our concept uses the medial sural nerve of patients undergoing diagnostic nerve biopsy (≥2 cm. The biopsy-induced nerve gap was immediately reconstructed by implantation of the novel microstructured nerve guide, Neuromaix, as part of an ongoing first-in-human study. Here we present (i a detailed list of inclusion and exclusion criteria, (ii a detailed description of the surgical procedure, and (iii a follow-up concept with multimodal sensory evaluation techniques. The proximal medial sural nerve biopsy model can serve as a preliminarynature of the injuries or baseline nerve lesion model. In a subsequent step, newly developed nerve guides could be tested in more unpredictable and challenging clinical peripheral nerve lesions (e.g., following trauma which have reduced comparability due to the different nature of the injuries (e.g., site of injury and length of nerve gap.
Baseline muscle mass is a poor predictor of functional overload-induced gain in the mouse model
Directory of Open Access Journals (Sweden)
Audrius Kilikevicius
2016-11-01
Full Text Available Genetic background contributes substantially to individual variability in muscle mass. Muscle hypertrophy in response to resistance training can also vary extensively. However, it is less clear if muscle mass at baseline is predictive of the hypertrophic response.The aim of this study was to examine the effect of genetic background on variability in muscle mass at baseline and in the adaptive response of the mouse fast- and slow-twitch muscles to overload. Males of eight laboratory mouse strains: C57BL/6J (B6, n=17, BALB/cByJ (n=7, DBA/2J (D2, n=12, B6.A-(rs3676616-D10Utsw1/Kjn (B6.A, n=9, C57BL/6J-Chr10A/J/NaJ (B6.A10, n=8, BEH+/+ (n=11, BEH (n=12 and DUHi (n=12, were studied. Compensatory growth of soleus and plantaris muscles was triggered by a 4-week overload induced by synergist unilateral ablation. Muscle weight in the control leg (baseline varied from 5.2±07 mg soleus and 11.4±1.3 mg plantaris in D2 mice to 18.0±1.7 mg soleus in DUHi and 43.7±2.6 mg plantaris in BEH (p<0.001 for both muscles. In addition, soleus in the B6.A10 strain was ~40% larger (p<0.001 compared to the B6. Functional overload increased muscle weight, however, the extent of gain was strain-dependent for both soleus (p<0.01 and plantaris (p<0.02 even after accounting for the baseline differences. For the soleus muscle, the BEH strain emerged as the least responsive, with a 1.3-fold increase, compared to a 1.7-fold gain in the most responsive D2 strain, and there was no difference in the gain between the B6.A10 and B6 strains. The BEH strain appeared the least responsive in the gain of plantaris as well, 1.3-fold, compared to ~1.5-fold gain in the remaining strains. We conclude that variation in muscle mass at baseline is not a reliable predictor of that in the overload-induced gain. This suggests that a different set of genes influence variability in muscle mass acquired in the process of normal development, growth and maintenance, and in the process of adaptive
Nijp, Jelmer J; Metselaar, Klaas; Limpens, Juul; Teutschbein, Claudia; Peichl, Matthias; Nilsson, Mats B; Berendse, Frank; van der Zee, Sjoerd E A T M
2017-02-15
The water content of the topsoil is one of the key factors controlling biogeochemical processes, greenhouse gas emissions and biosphere - atmosphere interactions in many ecosystems, particularly in northern peatlands. In these wetland ecosystems, the water content of the photosynthetic active peatmoss layer is crucial for ecosystem functioning and carbon sequestration, and is sensitive to future shifts in rainfall and drought characteristics. Current peatland models differ in the degree in which hydrological feedbacks are included, but how this affects peatmoss drought projections is unknown. The aim of this paper was to systematically test whether the level of hydrological detail in models could bias projections of water content and drought stress for peatmoss in northern peatlands using downscaled projections for rainfall and potential evapotranspiration in the current (1991-2020) and future climate (2061-2090). We considered four model variants that either include or exclude moss (rain)water storage and peat volume change, as these are two central processes in the hydrological self-regulation of peatmoss carpets. Model performance was validated using field data of a peatland in northern Sweden. Including moss water storage as well as peat volume change resulted in a significant improvement of model performance, despite the extra parameters added. The best performance was achieved if both processes were included. Including moss water storage and peat volume change consistently reduced projected peatmoss drought frequency with >50%, relative to the model excluding both processes. Projected peatmoss drought frequency in the growing season was 17% smaller under future climate than current climate, but was unaffected by including the hydrological self-regulating processes. Our results suggest that ignoring these two fine-scale processes important in hydrological self-regulation of northern peatlands will have large consequences for projected climate change impact on
Modeling an elastic beam with piezoelectric patches by including magnetic effects
Ozer, A O
2014-01-01
Models for piezoelectric beams using Euler-Bernoulli small displacement theory predict the dynamics of slender beams at the low frequency accurately but are insufficient for beams vibrating at high frequencies or beams with low length-to-width aspect ratios. A more thorough model that includes the effects of rotational inertia and shear strain, Mindlin-Timoshenko small displacement theory, is needed to predict the dynamics more accurately for these cases. Moreover, existing models ignore the magnetic effects since the magnetic effects are relatively small. However, it was shown recently \\cite{O-M1} that these effects can substantially change the controllability and stabilizability properties of even a single piezoelectric beam. In this paper, we use a variational approach to derive models that include magnetic effects for an elastic beam with two piezoelectric patches actuated by different voltage sources. Both Euler-Bernoulli and Mindlin-Timoshenko small displacement theories are considered. Due to the magne...
Stability analysis of the extended ADI-FDTD technique including lumped models
Institute of Scientific and Technical Information of China (English)
CHEN ZhiHui; CHU QingXin
2008-01-01
The numerical stability of the extended alternating-direction-implicit-finite-difference-time-domain (ADI-FDTD) method including lumped models is analyzed.Three common lumped models are investigated:resistor,capacitor,and inductor,and three different formulations for each model are analyzed:the explicit,semi-implicit and implicit schemes.Analysis results show that the extended ADI-FDTD algorithm is not unconditionally stable in the explicit scheme case,and the stability criterion depends on the value of lumped models,but in the semi-implicit and implicit cases,the algorithm is stable.Finally,two simple microstrip circuits including lumped elements are simulated to demonstrate validity of the theoretical results.
Directory of Open Access Journals (Sweden)
Shengxiang Jia
2003-01-01
Full Text Available This article presents a dynamic model of three shafts and two pair of gears in mesh, with 26 degrees of freedom, including the effects of variable tooth stiffness, pitch and profile errors, friction, and a localized tooth crack on one of the gears. The article also details howgeometrical errors in teeth can be included in a model. The model incorporates the effects of variations in torsional mesh stiffness in gear teeth by using a common formula to describe stiffness that occurs as the gears mesh together. The comparison between the presence and absence of geometrical errors in teeth was made by using Matlab and Simulink models, which were developed from the equations of motion. The effects of pitch and profile errors on the resultant input pinion angular velocity coherent-signal of the input pinion's average are discussed by investigating some of the common diagnostic functions and changes to the frequency spectra results.
SAMI2-PE: A model of the ionosphere including multistream interhemispheric photoelectron transport
Varney, R. H.; Swartz, W. E.; Hysell, D. L.; Huba, J. D.
2012-06-01
In order to improve model comparisons with recently improved incoherent scatter radar measurements at the Jicamarca Radio Observatory we have added photoelectron transport and energy redistribution to the two dimensional SAMI2 ionospheric model. The photoelectron model uses multiple pitch angle bins, includes effects associated with curved magnetic field lines, and uses an energy degradation procedure which conserves energy on coarse, non-uniformly spaced energy grids. The photoelectron model generates secondary electron production rates and thermal electron heating rates which are then passed to the fluid equations in SAMI2. We then compare electron and ion temperatures and electron densities of this modified SAMI2 model with measurements of these parameters over a range of altitudes from 90 km to 1650 km (L = 1.26) over a 24 hour period. The new electron heating model is a significant improvement over the semi-empirical model used in SAMI2. The electron temperatures above the F-peak from the modified model qualitatively reproduce the shape of the measurements as functions of time and altitude and quantitatively agree with the measurements to within ˜30% or better during the entire day, including during the rapid temperature increase at dawn.
Cappellari, Michele
2015-01-01
Cappellari (2008) presented a flexible and efficient method to model the stellar kinematics of anisotropic axisymmetric and spherical stellar systems. The spherical formalism could be used to model the line-of-sight velocity second moments allowing for essentially arbitrary radial variation in the anisotropy and general luminous and total density profiles. Here we generalize the spherical formalism by providing the expressions for all three components of the projected second moments, including the two proper motion components. A reference implementation is now included in the public JAM package available at http://purl.org/cappellari/software
Modeling Within-Host Dynamics of Influenza Virus Infection Including Immune Responses
Pawelek, Kasia A.; Huynh, Giao T; Michelle Quinlivan; Ann Cullinane; Libin Rong; Perelson, Alan S.
2012-01-01
Influenza virus infection remains a public health problem worldwide. The mechanisms underlying viral control during an uncomplicated influenza virus infection are not fully understood. Here, we developed a mathematical model including both innate and adaptive immune responses to study the within-host dynamics of equine influenza virus infection in horses. By comparing modeling predictions with both interferon and viral kinetic data, we examined the relative roles of target cell availability, ...
A lumped element transformer model including core losses and winding impedances
Ribbenfjärd, David
2007-01-01
In order to design a power transformer it is important to understand its internal electromagnetic behaviour. That can be obtained by measurements on physical transformers, analytical expressions and computer simulations. One benefit with simulations is that the transformer can be studied before it is built physically and that the consequences of changing dimensions and parameters easily can be tested. In this thesis a time-domain transformer model is presented. The model includes core losses ...
Target echo strength modelling at FOI, including results from the BeTSSi II workshop
Östberg, Martin
2016-01-01
An overview of the target echo strength (TS) modelling capacity at the Swedish Defense Research Agency (FOI) is presented. The modelling methods described range from approximate ones, such as raytracing and Kirchhoff approximation codes, to high accuracy full field codes including boundary integral equation methods and finite elements methods. Illustrations of the applicability of the codes are given for a few simple cases tackled during the BeTTSi II (Benchmark Target Echo Strength Simulation) workshop held in Kiel 2014.
Including leakage in network models: an application to calibrate leak valves in EPANET
Cobacho Jordán, Ricardo; Arregui de la Cruz, Francisco; Soriano Olivares, Javier; Cabrera Rochera, Enrique
2015-01-01
EPANET is one of the most widely used software packages for water network hydraulic modelling, and is especially interesting for educational and research purposes because it is in the public domain. However, EPANET simulations are demand-driven, and the program does not include a specific functionality to model water leakage, which is pressure-driven. Consequently, users are required to deal with this drawback by themselves. As a general solution for this problem, this paper presents a method...
Key Characteristics of Combined Accident including TLOFW accident for PSA Modeling
Energy Technology Data Exchange (ETDEWEB)
Kim, Bo Gyung; Kang, Hyun Gook [KAIST, Daejeon (Korea, Republic of); Yoon, Ho Joon [Khalifa University of Science, Technology and Research, Abu Dhabi (United Arab Emirates)
2015-05-15
The conventional PSA techniques cannot adequately evaluate all events. The conventional PSA models usually focus on single internal events such as DBAs, the external hazards such as fire, seismic. However, the Fukushima accident of Japan in 2011 reveals that very rare event is necessary to be considered in the PSA model to prevent the radioactive release to environment caused by poor treatment based on lack of the information, and to improve the emergency operation procedure. Especially, the results from PSA can be used to decision making for regulators. Moreover, designers can consider the weakness of plant safety based on the quantified results and understand accident sequence based on human actions and system availability. This study is for PSA modeling of combined accidents including total loss of feedwater (TLOFW) accident. The TLOFW accident is a representative accident involving the failure of cooling through secondary side. If the amount of heat transfer is not enough due to the failure of secondary side, the heat will be accumulated to the primary side by continuous core decay heat. Transients with loss of feedwater include total loss of feedwater accident, loss of condenser vacuum accident, and closure of all MSIVs. When residual heat removal by the secondary side is terminated, the safety injection into the RCS with direct primary depressurization would provide alternative heat removal. This operation is called feed and bleed (F and B) operation. Combined accidents including TLOFW accident are very rare event and partially considered in conventional PSA model. Since the necessity of F and B operation is related to plant conditions, the PSA modeling for combined accidents including TLOFW accident is necessary to identify the design and operational vulnerabilities.The PSA is significant to assess the risk of NPPs, and to identify the design and operational vulnerabilities. Even though the combined accident is very rare event, the consequence of combined
Hincapié, Doracelly; Ospina, Juan
2014-06-01
Recently, a mathematical model of pandemic influenza was proposed including typical control strategies such as antivirals, vaccination and school closure; and considering explicitly the effects of immunity acquired from the early outbreaks on the ulterior outbreaks of the disease. In such model the algebraic expression for the basic reproduction number (without control strategies) and the effective reproduction number (with control strategies) were derived and numerically estimated. A drawback of this model of pandemic influenza is that it ignores the effects of the differential susceptibility due to immunosuppression and the effects of the complexity of the actual contact networks between individuals. We have developed a generalized model which includes such effects of heterogeneity. Specifically we consider the influence of the air network connectivity in the spread of pandemic influenza and the influence of the immunosuppresion when the population is divided in two immune classes. We use an algebraic expression, namely the Tutte polynomial, to characterize the complexity of the contact network. Until now, The influence of the air network connectivity in the spread of pandemic influenza has been studied numerically, but not algebraic expressions have been used to summarize the level of network complexity. The generalized model proposed here includes the typical control strategies previously mentioned (antivirals, vaccination and school closure) combined with restrictions on travel. For the generalized model the corresponding reproduction numbers will be algebraically computed and the effect of the contact network will be established in terms of the Tutte polynomial of the network.
The No-Core Gamow Shell Model: Including the continuum in the NCSM
Barrett, B R; Michel, N; Płoszajczak, M
2015-01-01
We are witnessing an era of intense experimental efforts that will provide information about the properties of nuclei far from the line of stability, regarding resonant and scattering states as well as (weakly) bound states. This talk describes our formalism for including these necessary ingredients into the No-Core Shell Model by using the Gamow Shell Model approach. Applications of this new approach, known as the No-Core Gamow Shell Model, both to benchmark cases as well as to unstable nuclei will be given.
Energy Technology Data Exchange (ETDEWEB)
Chen, Y W [Surface Physics Laboratory and Department of Physics, Fudan University, Shanghai 200433 (China); Zhang, L F [Surface Physics Laboratory and Department of Physics, Fudan University, Shanghai 200433 (China); Huang, J P [Surface Physics Laboratory and Department of Physics, Fudan University, Shanghai 200433 (China)
2007-07-20
By using theoretical analysis and computer simulations, we develop the Watts-Strogatz network model by including degree distribution, in an attempt to improve the comparison between characteristic path lengths and clustering coefficients predicted by the original Watts-Strogatz network model and those of the real networks with the small-world property. Good agreement between the predictions of the theoretical analysis and those of the computer simulations has been shown. It is found that the developed Watts-Strogatz network model can fit the real small-world networks more satisfactorily. Some other interesting results are also reported by adjusting the parameters in a model degree-distribution function. The developed Watts-Strogatz network model is expected to help in the future analysis of various social problems as well as financial markets with the small-world property.
Dynamics Analysis of an HIV Infection Model including Infected Cells in an Eclipse Stage
Directory of Open Access Journals (Sweden)
Shengyu Zhou
2013-01-01
Full Text Available In this paper, an HIV infection model including an eclipse stage of infected cells is considered. Some quicker cells in this stage become productively infected cells, a portion of these cells are reverted to the uninfected class, and others will be latent down in the body. We consider CTL-response delay in this model and analyze the effect of time delay on stability of equilibrium. It is shown that the uninfected equilibrium and CTL-absent infection equilibrium are globally asymptotically stable for both ODE and DDE model. And we get the global stability of the CTL-present equilibrium for ODE model. For DDE model, we have proved that the CTL-present equilibrium is locally asymptotically stable in a range of delays and also have studied the existence of Hopf bifurcations at the CTL-present equilibrium. Numerical simulations are carried out to support our main results.
Modeling of the dynamics of wind to power conversion including high wind speed behavior
DEFF Research Database (Denmark)
Litong-Palima, Marisciel; Bjerge, Martin Huus; Cutululis, Nicolaos Antonio
2016-01-01
of power system studies, but the idea of the proposed wind turbine model is to include the main dynamic effects in order to have a better representation of the fluctuations in the output power and of the fast power ramping especially because of high wind speed shutdowns of the wind turbine. The high wind......This paper proposes and validates an efficient, generic and computationally simple dynamic model for the conversion of the wind speed at hub height into the electrical power by a wind turbine. This proposed wind turbine model was developed as a first step to simulate wind power time series...... for power system studies. This paper focuses on describing and validating the single wind turbine model, and is therefore neither describing wind speed modeling nor aggregation of contributions from a whole wind farm or a power system area. The state-of-the-art is to use static power curves for the purpose...
A statistical model including age to predict passenger postures in the rear seats of automobiles.
Park, Jangwoon; Ebert, Sheila M; Reed, Matthew P; Hallman, Jason J
2016-06-01
Few statistical models of rear seat passenger posture have been published, and none has taken into account the effects of occupant age. This study developed new statistical models for predicting passenger postures in the rear seats of automobiles. Postures of 89 adults with a wide range of age and body size were measured in a laboratory mock-up in seven seat configurations. Posture-prediction models for female and male passengers were separately developed by stepwise regression using age, body dimensions, seat configurations and two-way interactions as potential predictors. Passenger posture was significantly associated with age and the effects of other two-way interaction variables depended on age. A set of posture-prediction models are presented for women and men, and the prediction results are compared with previously published models. This study is the first study of passenger posture to include a large cohort of older passengers and the first to report a significant effect of age for adults. The presented models can be used to position computational and physical human models for vehicle design and assessment. Practitioner Summary: The significant effects of age, body dimensions and seat configuration on rear seat passenger posture were identified. The models can be used to accurately position computational human models or crash test dummies for older passengers in known rear seat configurations.
Oscillation Baselining and Analysis Tool
Energy Technology Data Exchange (ETDEWEB)
2017-03-27
PNNL developed a new tool for oscillation analysis and baselining. This tool has been developed under a new DOE Grid Modernization Laboratory Consortium (GMLC) Project (GM0072 - “Suite of open-source applications and models for advanced synchrophasor analysis”) and it is based on the open platform for PMU analysis. The Oscillation Baselining and Analysis Tool (OBAT) performs the oscillation analysis and identifies modes of oscillations (frequency, damping, energy, and shape). The tool also does oscillation event baselining (fining correlation between oscillations characteristics and system operating conditions).
Kelly, Jeff; Betts, Juan Fernando; Fuller, Chris
2000-01-01
The study of normal impedance of perforated plate acoustic liners including the effect of bias flow was studied. Two impedance models were developed by modeling the internal flows of perforate orifices as infinite tubes with the inclusion of end corrections to handle finite length effects. These models assumed incompressible and compressible flows, respectively, between the far field and the perforate orifice. The incompressible model was used to predict impedance results for perforated plates with percent open areas ranging from 5% to 15%. The predicted resistance results showed better agreement with experiments for the higher percent open area samples. The agreement also tended to deteriorate as bias flow was increased. For perforated plates with percent open areas ranging from 1% to 5%, the compressible model was used to predict impedance results. The model predictions were closer to the experimental resistance results for the 2% to 3% open area samples. The predictions tended to deteriorate as bias flow was increased. The reactance results were well predicted by the models for the higher percent open area, but deteriorated as the percent open area was lowered (5%) and bias flow was increased. A fit was done on the incompressible model to the experimental database. The fit was performed using an optimization routine that found the optimal set of multiplication coefficients to the non-dimensional groups that minimized the least squares slope error between predictions and experiments. The result of the fit indicated that terms not associated with bias flow required a greater degree of correction than the terms associated with the bias flow. This model improved agreement with experiments by nearly 15% for the low percent open area (5%) samples when compared to the unfitted model. The fitted model and the unfitted model performed equally well for the higher percent open area (10% and 15%).
Fusion rules for the logarithmic $N=1$ superconformal minimal models II: including the Ramond sector
Canagasabey, Michael
2015-01-01
The Virasoro logarithmic minimal models were intensively studied by several groups over the last ten years with much attention paid to the fusion rules and the structures of the indecomposable representations that fusion generates. The analogous study of the fusion rules of the $N=1$ superconformal logarithmic minimal models was initiated in arXiv:1504.03155 as a continuum counterpart to the lattice explorations of arXiv:1312.6763. These works restricted fusion considerations to Neveu-Schwarz representations. Here, this is extended to include the Ramond sector. Technical advances that make this possible include a fermionic Verlinde formula applicable to logarithmic conformal field theories and a twisted version of the fusion algorithm of Nahm and Gaberdiel-Kausch. The results include the first construction and detailed analysis of logarithmic structures in the Ramond sector.
MEMLS3&a: Microwave Emission Model of Layered Snowpacks adapted to include backscattering
Directory of Open Access Journals (Sweden)
M. Proksch
2015-08-01
Full Text Available The Microwave Emission Model of Layered Snowpacks (MEMLS was originally developed for microwave emissions of snowpacks in the frequency range 5–100 GHz. It is based on six-flux theory to describe radiative transfer in snow including absorption, multiple volume scattering, radiation trapping due to internal reflection and a combination of coherent and incoherent superposition of reflections between horizontal layer interfaces. Here we introduce MEMLS3&a, an extension of MEMLS, which includes a backscatter model for active microwave remote sensing of snow. The reflectivity is decomposed into diffuse and specular components. Slight undulations of the snow surface are taken into account. The treatment of like- and cross-polarization is accomplished by an empirical splitting parameter q. MEMLS3&a (as well as MEMLS is set up in a way that snow input parameters can be derived by objective measurement methods which avoid fitting procedures of the scattering efficiency of snow, required by several other models. For the validation of the model we have used a combination of active and passive measurements from the NoSREx (Nordic Snow Radar Experiment campaign in Sodankylä, Finland. We find a reasonable agreement between the measurements and simulations, subject to uncertainties in hitherto unmeasured input parameters of the backscatter model. The model is written in Matlab and the code is publicly available for download through the following website: http://www.iapmw.unibe.ch/research/projects/snowtools/memls.html.
MEMLS3&a: Microwave Emission Model of Layered Snowpacks adapted to include backscattering
Directory of Open Access Journals (Sweden)
M. Proksch
2015-03-01
Full Text Available The Microwave Emission Model of Layered Snowpacks (MEMLS was originally developed for microwave emissions of snowpacks in the frequency range 5–100 GHz. It is based on six-flux theory to describe radiative transfer in snow including absorption, multiple volume scattering, radiation trapping due to internal reflection and a combination of coherent and incoherent superposition of reflections between horizontal layer interfaces. Here we introduce MEMLS3&a, an extension of MEMLS, which includes a backscatter model for active microwave remote sensing of snow. The reflectivity is decomposed into diffuse and specular components. Slight undulations of the snow surface are taken into account. The treatment of like and cross polarization is accomplished by an empirical splitting parameter q. MEMLS3&a (as well as MEMLS is set up in a way that snow input parameters can be derived by objective measurement methods which avoids fitting procedures of the scattering efficiency of snow, required by several other models. For the validation of the model we have used a combination of active and passive measurements from the NoSREx campaign in Sodankylä, Finland. We find a reasonable agreement between the measurements and simulations, subject to uncertainties in hitherto unmeasured input parameters of the backscatter model. The model is written in MATLAB and the code is publicly available for download through the following website: http://www.iapmw.unibe.ch/research/projects/snowtools/memls.html.
MEMLS3&a: Microwave Emission Model of Layered Snowpacks adapted to include backscattering
Proksch, M.; Mätzler, C.; Wiesmann, A.; Lemmetyinen, J.; Schwank, M.; Löwe, H.; Schneebeli, M.
2015-08-01
The Microwave Emission Model of Layered Snowpacks (MEMLS) was originally developed for microwave emissions of snowpacks in the frequency range 5-100 GHz. It is based on six-flux theory to describe radiative transfer in snow including absorption, multiple volume scattering, radiation trapping due to internal reflection and a combination of coherent and incoherent superposition of reflections between horizontal layer interfaces. Here we introduce MEMLS3&a, an extension of MEMLS, which includes a backscatter model for active microwave remote sensing of snow. The reflectivity is decomposed into diffuse and specular components. Slight undulations of the snow surface are taken into account. The treatment of like- and cross-polarization is accomplished by an empirical splitting parameter q. MEMLS3&a (as well as MEMLS) is set up in a way that snow input parameters can be derived by objective measurement methods which avoid fitting procedures of the scattering efficiency of snow, required by several other models. For the validation of the model we have used a combination of active and passive measurements from the NoSREx (Nordic Snow Radar Experiment) campaign in Sodankylä, Finland. We find a reasonable agreement between the measurements and simulations, subject to uncertainties in hitherto unmeasured input parameters of the backscatter model. The model is written in Matlab and the code is publicly available for download through the following website: http://www.iapmw.unibe.ch/research/projects/snowtools/memls.html.
Diagnosing Lee Wave Rotor Onset Using a Linear Model Including a Boundary Layer
Directory of Open Access Journals (Sweden)
Miguel A. C. Teixeira
2017-01-01
Full Text Available A linear model is used to diagnose the onset of rotors in flow over 2D hills, for atmospheres that are neutrally stratified near the surface and stably stratified aloft, with a sharp temperature inversion in between, where trapped lee waves may propagate. This is achieved by coupling an inviscid two-layer mountain-wave model and a bulk boundary-layer model. The full model shows some ability to diagnose flow stagnation associated with rotors as a function of key input parameters, such as the Froude number and the height of the inversion, in numerical simulations and laboratory experiments carried out by previous authors. While calculations including only the effects of mean flow attenuation and velocity perturbation amplification within the surface layer represent flow stagnation fairly well in the more non-hydrostatic cases, only the full model, taking into account the feedback of the surface layer on the inviscid flow, satisfactorily predicts flow stagnation in the most hydrostatic case, although the corresponding condition is unable to discriminate between rotors and hydraulic jumps. Versions of the model not including this feedback severely underestimate the amplitude of trapped lee waves in that case, where the Fourier transform of the hill has zeros, showing that those waves are not forced directly by the orography.
Diehl, S; Zambrano, J; Carlsson, B
2016-01-01
A reduced model of a completely stirred-tank bioreactor coupled to a settling tank with recycle is analyzed in its steady states. In the reactor, the concentrations of one dominant particulate biomass and one soluble substrate component are modelled. While the biomass decay rate is assumed to be constant, growth kinetics can depend on both substrate and biomass concentrations, and optionally model substrate inhibition. Compressive and hindered settling phenomena are included using the Bürger-Diehl settler model, which consists of a partial differential equation. Steady-state solutions of this partial differential equation are obtained from an ordinary differential equation, making steady-state analysis of the entire plant difficult. A key result showing that the ordinary differential equation can be replaced with an approximate algebraic equation simplifies model analysis. This algebraic equation takes the location of the sludge-blanket during normal operation into account, allowing for the limiting flux capacity caused by compressive settling to easily be included in the steady-state mass balance equations for the entire plant system. This novel approach grants the possibility of more realistic solutions than other previously published reduced models, comprised of yet simpler settler assumptions. The steady-state concentrations, solids residence time, and the wastage flow ratio are functions of the recycle ratio. Solutions are shown for various growth kinetics; with different values of biomass decay rate, influent volumetric flow, and substrate concentration.
Institute of Scientific and Technical Information of China (English)
Nan Liang; Pu-Xun Wua; Zong-Hong Zhu
2011-01-01
We constrain the Cardassian expansion models from the latest observations,including the updated Gamma-ray bursts (GRBs),which are calibrated using a cosmology independent method from the Union2 compilation of type Ia supernovae (SNe Ia).By combining the GRB data with the joint observations from the Union2SNe Ia set,along with the results from the Cosmic Microwave Background radiation observation from the seven-year Wilkinson Microwave Anisotropy Probe and the baryonic acoustic oscillation observation galaxy sample from the spectroscopic Sloan Digital Sky Survey Data Release,we find significant constraints on the model parameters of the original Cardassian model ΩM0=n 282+0.015-0.014,n=0.03+0.05-0.05;and n = -0.16+0.25-3.26,β=-0.76+0.34-0.58 of the modified polytropic Cardassian model,which are consistent with the ACDM model in a l-σ confidence region.From the reconstruction of the deceleration parameter q(z) in Cardassian models,we obtain the transition redshift ZT = 0.73 ± 0.04 for the original Cardassian model and ZT = 0.68 ± 0.04 for the modified polytropic Cardassian model.
Safe distance car-following model including backward-looking and its stability analysis
Yang, Da; Jin, Peter Jing; Pu, Yun; Ran, Bin
2013-03-01
The focus of this paper is the car-following behavior including backward-looking, simply called the bi-directional looking car-following behavior. This study is motivated by the potential changes of the physical properties of traffic flow caused by the fast developing intelligent transportation system (ITS), especially the new connected vehicle technology. Existing studies on this topic focused on general motors (GM) models and optimal velocity (OV) models. The safe distance car-following model, Gipps' model, which is more widely used in practice have not drawn too much attention in the bi-directional looking context. This paper explores the property of the bi-directional looking extension of Gipps' safe distance model. The stability condition of the proposed model is derived using the linear stability theory and is verified using numerical simulations. The impacts of the driver and vehicle characteristics appeared in the proposed model on the traffic flow stability are also investigated. It is found that taking into account the backward-looking effect in car-following has three types of effect on traffic flow: stabilizing, destabilizing and producing non-physical phenomenon. This conclusion is more sophisticated than the study results based on the OV bi-directional looking car-following models. Moreover, the drivers who have the smaller reaction time or the larger additional delay and think the other vehicles have larger maximum decelerations can stabilize traffic flow.
DEFF Research Database (Denmark)
Bahman, Amir Sajjad; Ma, Ke; Blaabjerg, Frede
2017-01-01
Detailed thermal dynamics of high power IGBT modules are important information for the reliability analysis and thermal design of power electronic systems. However, the existing thermal models have their limits to correctly predict these complicated thermal behavior in the IGBTs: The typically used...... thermal distribution under long-term studies. Meanwhile the boundary conditions for the thermal analysis are modeled and included, which can be adapted to different real field applications of power electronic converters. Finally, the accuracy of the proposed thermal model is verified by FEM simulations...... thermal model based on one-dimensional RC lumps have limits to provide temperature distributions inside the device, moreover some variable factors in the real-field applications like the cooling and heating conditions of the converter cannot be adapted. On the other hand, the more advanced three...
DEFF Research Database (Denmark)
Bahman, Amir Sajjad; Ma, Ke; Blaabjerg, Frede
2017-01-01
Detailed thermal dynamics of high power IGBT modules are important information for the reliability analysis and thermal design of power electronic systems. However, the existing thermal models have their limits to correctly predict these complicated thermal behavior in the IGBTs: The typically used...... thermal distribution under long-term studies. Meanwhile the boundary conditions for the thermal analysis are modeled and included, which can be adapted to different real-field applications of power electronic converters. Finally, the accuracy of the proposed thermal model is verified by FEM simulations...... thermal model based on one-dimensional RC lumps have limits to provide temperature distributions inside the device, moreover some variable factors in the real-field applications like the cooling and heating conditions of the converter cannot be adapted. On the other hand, the more advanced three...
Xia, Mingjun; Ghafouri-Shiraz, H
2016-03-01
This paper reports a new model for strained quantum well lasers, which are based on the quantum well transmission line modeling method where effects of both carrier transport and carrier heating have been included. We have applied this new model and studied the effect of carrier transport on the output waveform of a strained quantum well laser both in time and frequency domains. It has been found that the carrier transport increases the turn-on, turn-off delay times and damping of the quantum well laser transient response. Also, analysis in the frequency domain indicates that the carrier transport causes the output spectrum of the quantum well laser in steady state to exhibit a redshift which has a narrower bandwidth and lower magnitude. The simulation results of turning-on transients obtained by the proposed model are compared with those obtained by the rate equation laser model. The new model has also been used to study the effects of pump current spikes on the laser output waveforms properties, and it was found that the presence of current spikes causes (i) wavelength blueshift, (ii) larger bandwidth, and (iii) reduces the magnitude and decreases the side-lobe suppression ratio of the laser output spectrum. Analysis in both frequency and time domains confirms that the new proposed model can accurately predict the temporal and spectral behaviors of strained quantum well lasers.
A numerical model including PID control of a multizone crystal growth furnace
Panzarella, Charles H.; Kassemi, Mohammad
This paper presents a 2D axisymmetric combined conduction and radiation model of a multizone crystal growth furnace. The model is based on a programmable multizone furnace (PMZF) designed and built at NASA Lewis Research Center for growing high quality semiconductor crystals. A novel feature of this model is a control algorithm which automatically adjusts the power in any number of independently controlled heaters to establish the desired crystal temperatures in the furnace model. The control algorithm eliminates the need for numerous trial and error runs previously required to obtain the same results. The finite element code, FIDAP, used to develop the furnace model, was modified to directly incorporate the control algorithm. This algorithm, which presently uses PID control, and the associated heat transfer model are briefly discussed. Together, they have been used to predict the heater power distributions for a variety of furnace configurations and desired temperature profiles. Examples are included to demonstrate the effectiveness of the PID controlled model in establishing isothermal, Bridgman, and other complicated temperature profies in the sample. Finally, an example is given to show how the algorithm can be used to change the desired profile with time according to a prescribed temperature-time evolution.
Duignan, Timothy T; Parsons, Drew F; Ninham, Barry W
2013-08-15
Physically accurate continuum solvent models that can calculate solvation energies are crucial to explain and predict the behavior of solute particles in water. Here, we present such a model applied to small spherical ions and neutral atoms. It improves upon a basic Born electrostatic model by including a standard cavity energy and adding a dispersion component, consistent with the Born electrostatic energy and using the same cavity size parameter. We show that the well-known, puzzling differences between the solvation energies of ions of the same size is attributable to the neglected dispersion contribution. This depends on dynamic polarizability as well as size. Generally, a large cancellation exists between the cavity and dispersion contributions. This explains the surprising success of the Born model. The model accurately reproduces the solvation energies of the alkali halide ions, as well as the silver(I) and copper(I) ions with an error of 12 kJ mol(-1) (±3%). The solvation energy of the noble gases is also reproduced with an error of 2.6 kJ mol(-1) (±30%). No arbitrary fitting parameters are needed to achieve this. This model significantly improves our understanding of ionic solvation and forms a solid basis for the investigation of other ion-specific effects using a continuum solvent model.
Model for resistance evolution in shape memory alloys including R-phase
Brammajyosula, Ravindra; Buravalla, Vidyashankar; Khandelwal, Ashish
2011-03-01
The electrical resistance behavior of a shape memory alloy (SMA) wire can be used for sensing the state of an SMA device. Hence, this study investigates the resistance evolution in SMAs. A lumped parameter model with cosine kinetics to capture the resistance variation during the phase transformation is developed. Several SMA materials show the presence of trigonal or rhombohedral (R) phase as an intermediate phase, apart from the commonly recognized austenite and martensite phases. Most of the SMA models ignore the R-phase effect in their prediction of thermomechanical response. This may be acceptable since the changes in thermomechanical response associated with the R-phase are relatively less. However, the resistivity related effects are pronounced in the presence of the R-phase and its appearance introduces non-monotonicity in the resistivity evolution. This leads to additional complexities in the use of resistance signal for sensing and control. Hence, a lumped model is developed here for resistance evolution including the R-phase effects. A phase-diagram-based model is proposed for predicting electro-thermomechanical response. Both steady state hysteretic response and transient response are modeled. The model predictions are compared with the available test data. Numerical studies have shown that the model is able to capture all the essential features of the resistance evolution in SMAs in the presence of the R-phase.
Directory of Open Access Journals (Sweden)
Hyein Lim
2013-01-01
Full Text Available Spin-torque oscillator (STO is a promising new technology for the future RF oscillators, which is based on the spin-transfer torque (STT effect in magnetic multilayered nanostructure. It is expected to provide a larger tunability, smaller size, lower power consumption, and higher level of integration than the semiconductor-based oscillators. In our previous work, a circuit-level model of the giant magnetoresistance (GMR STO was proposed. In this paper, we present a physics-based circuit-level model of the magnetic tunnel junction (MTJ-based STO. MTJ-STO model includes the effect of perpendicular torque that has been ignored in the GMR-STO model. The variations of three major characteristics, generation frequency, mean oscillation power, and generation linewidth of an MTJ-STO with respect to the amount of perpendicular torque, are investigated, and the results are applied to our model. The operation of the model was verified by HSPICE simulation, and the results show an excellent agreement with the experimental data. The results also prove that a full circuit-level simulation with MJT-STO devices can be made with our proposed model.
Buckley, Lauren B; Waaser, Stephanie A; MacLean, Heidi J; Fox, Richard
2011-12-01
Thermal constraints on development are often invoked to predict insect distributions. These constraints tend to be characterized in species distribution models (SDMs) by calculating development time based on a constant lower development temperature (LDT). Here, we assessed whether species-specific estimates of LDT based on laboratory experiments can improve the ability of SDMs to predict the distribution shifts of six U.K. butterflies in response to recent climate warming. We find that species-specific and constant (5 degrees C) LDT degree-day models perform similarly at predicting distributions during the period of 1970-1982. However, when the models for the 1970-1982 period are projected to predict distributions in 1995-1999 and 2000-2004, species-specific LDT degree-day models modestly outperform constant LDT degree-day models. Our results suggest that, while including species-specific physiology in correlative models may enhance predictions of species' distribution responses to climate change, more detailed models may be needed to adequately account for interspecific physiological differences.
Modeling of single char combustion, including CO oxidation in its boundary layer
Energy Technology Data Exchange (ETDEWEB)
Lee, C.H.; Longwell, J.P.; Sarofim, A.F.
1994-10-25
The combustion of a char particle can be divided into a transient phase where its temperature increases as it is heated by oxidation, and heat transfer from the surrounding gas to an approximately constant temperature stage where gas phase reaction is important and which consumes most of the carbon and an extinction stage caused by carbon burnout. In this work, separate models were developed for the transient heating where gas phase reactions were unimportant and for the steady temperature stage where gas phase reactions were treated in detail. The transient char combustion model incorporates intrinsic char surface production of CO and CO{sub 2}, internal pore diffusion and external mass and heat transfer. The model provides useful information for particle ignition, burning temperature profile, combustion time, and carbon consumption rate. A gas phase reaction model incorporating the full set of 28 elementary C/H/O reactions was developed. This model calculated the gas phase CO oxidation reaction in the boundary layer at particle temperatures of 1250 K and 2500 K by using the carbon consumption rate and the burning temperature at the pseudo-steady state calculated from the temperature profile model but the transient heating was not included. This gas phase model can predict the gas species, and the temperature distributions in the boundary layer, the CO{sub 2}/CO ratio, and the location of CO oxidation. A mechanistic heat and mass transfer model was added to the temperature profile model to predict combustion behavior in a fluidized bed. These models were applied to data from the fluidized combustion of Newlands coal char particles. 52 refs., 60 figs.
Including source uncertainty and prior information in the analysis of stable isotope mixing models.
Ward, Eric J; Semmens, Brice X; Schindler, Daniel E
2010-06-15
Stable isotope mixing models offer a statistical framework for estimating the contribution of multiple sources (such as prey) to a mixture distribution. Recent advances in these models have estimated the source proportions using Bayesian methods, but have not explicitly accounted for uncertainty in the mean and variance of sources. We demonstrate that treating these quantities as unknown parameters can reduce bias in the estimated source contributions, although model complexity is increased (thereby increasing the variance of estimates). The advantages of this fully Bayesian approach are particularly apparent when the source geometry is poor or sample sizes are small. A second benefit to treating source quantities as parameters is that prior source information can be included. We present findings from 9 lake food-webs, where the consumer of interest (fish) has a diet composed of 5 sources: aquatic insects, snails, zooplankton, amphipods, and terrestrial insects. We compared the traditional Bayesian stable isotope mixing model with fixed source parameters to our fully Bayesian model-with and without an informative prior. The informative prior has much less impact than the choice of model-the traditional mixing model with fixed source parameters estimates the diet to be dominated by aquatic insects, while the fully Bayesian model estimates the diet to be more balanced but with greater importance of zooplankton. The findings from this example demonstrate that there can be stark differences in inference between the two model approaches, particularly when the source geometry of the mixing model is poor. These analyses also emphasize the importance of investing substantial effort toward characterizing the variation in the isotopic characteristics of source pools to appropriately quantify uncertainties in their contributions to consumers in food webs.
Henkel, Marius; Schmidberger, Anke; Vogelbacher, Markus; Kühnert, Christian; Beuker, Janina; Bernard, Thomas; Schwartz, Thomas; Syldatk, Christoph; Hausmann, Rudolf
2014-08-01
The production of rhamnolipid biosurfactants by Pseudomonas aeruginosa is under complex control of a quorum sensing-dependent regulatory network. Due to a lack of understanding of the kinetics applicable to the process and relevant interrelations of variables, current processes for rhamnolipid production are based on heuristic approaches. To systematically establish a knowledge-based process for rhamnolipid production, a deeper understanding of the time-course and coupling of process variables is required. By combining reaction kinetics, stoichiometry, and experimental data, a process model for rhamnolipid production with P. aeruginosa PAO1 on sunflower oil was developed as a system of coupled ordinary differential equations (ODEs). In addition, cell density-based quorum sensing dynamics were included in the model. The model comprises a total of 36 parameters, 14 of which are yield coefficients and 7 of which are substrate affinity and inhibition constants. Of all 36 parameters, 30 were derived from dedicated experimental results, literature, and databases and 6 of them were used as fitting parameters. The model is able to describe data on biomass growth, substrates, and products obtained from a reference batch process and other validation scenarios. The model presented describes the time-course and interrelation of biomass, relevant substrates, and products on a process level while including a kinetic representation of cell density-dependent regulatory mechanisms.
Codigestion of solid wastes: a review of its uses and perspectives including modeling.
Mata-Alvarez, Joan; Dosta, Joan; Macé, Sandra; Astals, Sergi
2011-06-01
The last two years have witnessed a dramatic increase in the number of papers published on the subject of codigestion, highlighting the relevance of this topic within anaerobic digestion research. Consequently, it seems appropriate to undertake a review of codigestion practices starting from the late 1970s, when the first papers related to this concept were published, and continuing to the present day, demonstrating the exponential growth in the interest shown in this approach in recent years. Following a general analysis of the situation, state-of-the-art codigestion is described, focusing on the two most important areas as regards publication: codigestion involving sewage sludge and the organic fraction of municipal solid waste (including a review of the secondary advantages for wastewater treatment plant related to biological nutrient removal), and codigestion in the agricultural sector, that is, including agricultural - farm wastes, and energy crops. Within these areas, a large number of oversized digesters appear which can be used to codigest other substrates, resulting in economic and environmental advantages. Although the situation may be changing, there is still a need for good examples on an industrial scale, particularly with regard to wastewater treatment plants, in order to extend this beneficial practice. In the last section, a detailed analysis of papers addressing the important aspect of modelisation is included. This analysis includes the first codigestion models to be developed as well as recent applications of the standardised anaerobic digestion model ADM1 to codigestion. (This review includes studies ranging from laboratory to industrial scale.).
Enhanced UWB Radio Channel Model for Short-Range Communication Scenarios Including User Dynamics
DEFF Research Database (Denmark)
Kovacs, Istvan Zsolt; Nguyen, Tuan Hung; Eggers, Patrick Claus F.
2005-01-01
In this paper we propose a SISO UWB radio channel model for short-range radio link scenarios between a fixed device and a dynamic user hand-held device. The channel model is derived based on novel experimental UWB radio propagation investigations carried out in typical indoor PAN scenarios...... including realistic device and user terminal antenna configurations. The radio channel measurements have been performed in the lower UWB frequency band of 3GHz to 5GHz with a 2x4 MIMO antenna configuration. Several environments, user scenarios and two types of user terminals have been used. The developed...
Directory of Open Access Journals (Sweden)
Hossein Sadegh Lafmejani
2015-09-01
Full Text Available Fuzzy logic controller (FLC is a heuristic method by If-Then Rules which resembles human intelligence and it is a good method for designing Non-linear control systems. In this paper, an arbitrary helicopter model includes articulated manipulators has been simulated with Matlab SimMechanics toolbox. Due to the difficulties of modeling this complex system, a fuzzy controller with simple fuzzy rules has been designed for its yaw and roll angles in order to stabilize the helicopter while it is in the presence of disturbances or its manipulators are moving for a task. Results reveal that a simple FLC can appropriately control this system.
Including Finite Surface Span Effects in Empirical Jet-Surface Interaction Noise Models
Brown, Clifford A.
2016-01-01
The effect of finite span on the jet-surface interaction noise source and the jet mixing noise shielding and reflection effects is considered using recently acquired experimental data. First, the experimental setup and resulting data are presented with particular attention to the role of surface span on far-field noise. These effects are then included in existing empirical models that have previously assumed that all surfaces are semi-infinite. This extended abstract briefly describes the experimental setup and data leaving the empirical modeling aspects for the final paper.
Fuller, C. R.
1986-01-01
A simplified analytical model of transmission of noise into the interior of propeller-driven aircraft has been developed. The analysis includes directivity and relative phase effects of the propeller noise sources, and leads to a closed form solution for the coupled motion between the interior and exterior fields via the shell (fuselage) vibrational response. Various situations commonly encountered in considering sound transmission into aircraft fuselages are investigated analytically and the results obtained are compared to measurements in real aircraft. In general the model has proved successful in identifying basic mechanisms behind noise transmission phenomena.
An air/sea flux model including the effects of capillary waves
Bourassa, Mark A.
1993-01-01
An improved model of the air/sea interface is developed. The improvements consist in including the effect of capillary (surface tension) waves on the tropical surface fluxes and the consideration of the sea state, both of which increase the magnitude of tropical surface fluxes. Changes in surface stress are most significant in the low wind-speed regions, which include the areas where westerly bursts occur. It is shown that the changes, from the regular wind conditions to those of a westerly burst or El-Nino, can double when the effects of capillary waves are considered. This implies a much stronger coupling between the ocean and the atmosphere than is predicted by other boundary layer models.
A complete model of CH+ rotational excitation including radiative and chemical pumping processes
Godard, Benjamin
2012-01-01
Aims. Excitation of far-infrared and submillimetric molecular lines may originate from nonreactive collisions, chemical formation, or far infrared, near-infrared, and optical fluorescences. As a template, we investigate the impact of each of these processes on the excitation of the methylidyne cation CH+ and on the intensities of its rotational transitions recently detected in emission in dense photodissociation regions (PDRs) and in planetary nebulae. Methods. We have developed a nonlocal thermodynamic equilibrium (non-LTE) excitation model that includes the entire energy structure of CH+, i.e. taking into account the pumping of its vibrational and bound and unbound electronic states by near-infrared and optical photons. The model includes the theoretical cross-sections of nonreactive collisions with H, H2, He, and e-, and a Boltzmann distribution is used to describe the probability of populating the excited levels of CH+ during its chemical formation by hydrogenation of C+. To confirm our results we also pe...
Including Flocculation in a Numerical Sediment Transport Model for a Partially-Mixed Estuary
Tarpley, D.; Harris, C. K.; Friedrichs, C. T.
2016-12-01
Particle settling velocity impacts the transport of suspended sediment to the first order but fine-grained material like muds tend to form loosely bound aggregates (flocs) whose settling velocity can vary widely. Properties of flocculated sediment such as settling velocity and particle density are difficult to predict because they change in response to several factors including salinity, suspended sediment concentration, turbulent mixing, and organic content. Knowledge of the mechanisms governing flocculation of cohesive sediment is rapidly expanding; especially in response to recent technical advances. As the understanding of particle dynamics progresses, numerical models describing flocculation and break-up are being developed with varying degrees of complexity. While complex models capture the dynamics of the system, their computational costs may prohibit their incorporation into larger model domains. It is important to determine if the computational costs of intricate floc models are justifiable compared to simpler formulations. For this study, we implement an idealized two-dimensional model designed to represent a longitudinal section of a partially mixed estuary that neglects across-channel variation but exhibits salinity driven estuarine circulation. The idealized domain is designed to mimic the primary features of the York River, VA. Suspended load, erosion and deposition are calculated within the sediment transport routines of the COAWST modeling system. We compare different methods for prescribing settling velocity of fine-grained material. The simplest, standard model neglects flocculation dynamics while the complex treatment is a size-class-based flocculation model (FLOCMOD). Differences in tidal and daily averages of suspended load, bulk settling velocity and bed deposition are compared between the standard and FLOCMOD runs, to examine the relative impact of flocculation on sediment transport patterns. We expect FLOCMOD to have greater variability and
Bongers, Mathilda L; de Ruysscher, Dirk; Oberije, Cary; Lambin, Philippe; Uyl-de Groot, Carin A; Coupé, V M H
2016-01-01
With the shift toward individualized treatment, cost-effectiveness models need to incorporate patient and tumor characteristics that may be relevant to treatment planning. In this study, we used multistate statistical modeling to inform a microsimulation model for cost-effectiveness analysis of individualized radiotherapy in lung cancer. The model tracks clinical events over time and takes patient and tumor features into account. Four clinical states were included in the model: alive without progression, local recurrence, metastasis, and death. Individual patients were simulated by repeatedly sampling a patient profile, consisting of patient and tumor characteristics. The transitioning of patients between the health states is governed by personalized time-dependent hazard rates, which were obtained from multistate statistical modeling (MSSM). The model simulations for both the individualized and conventional radiotherapy strategies demonstrated internal and external validity. Therefore, MSSM is a useful technique for obtaining the correlated individualized transition rates that are required for the quantification of a microsimulation model. Moreover, we have used the hazard ratios, their 95% confidence intervals, and their covariance to quantify the parameter uncertainty of the model in a correlated way. The obtained model will be used to evaluate the cost-effectiveness of individualized radiotherapy treatment planning, including the uncertainty of input parameters. We discuss the model-building process and the strengths and weaknesses of using MSSM in a microsimulation model for individualized radiotherapy in lung cancer.
Energy Technology Data Exchange (ETDEWEB)
NONE
1995-12-01
Several safety reports will be produced in the process of planning and constructing the system for disposal of high-level radioactive waste in Sweden. The present report gives a model, with detailed examples, of how these reports should be organized and what steps they should include. In the near future safety reports will deal with the encapsulation plant and the repository. Later reports will treat operation of the handling systems and the repository.
CSIR Research Space (South Africa)
Cooper, Antony K
2011-07-01
Full Text Available an aggregator of VGI, such as Ushahidi, and the provider of the infrastructure for collecting VGI, such as OpenStreetMap. 3) Broker: A stakeholder who brings End Users and Providers together and assists in the negotiation of contracts between them... model of a spatial data infrastructure to include volunteered geographical information Antony K Cooper*, Petr Rapant?, Jan Hjelmager?, Dominique Laurent?, Adam Iwaniak#, Serena Coetzee$, Harold Moellering? and Ulrich D?ren? *Logistics...
2007-11-01
standards in Europe and the US at the 10-15 uncertainty level,” Metrologia , 43, 109-120. [2] D. Piester, A. Bauch, L. Breakiron, D. Matsakis, B...Blanzano, and O. Koudelka, 2008, “Time transfer with nanosecond accuracy for the realization of International Atomic Time,” submitted to Metrologia
QCD Equation of State From a Chiral Hadronic Model Including Quark Degrees of Freedom
Rau, Philip; Schramm, Stefan; Stöcker, Horst
2013-01-01
This work presents an effective model for strongly interacting matter and the QCD equation of state (EoS). The model includes both hadron and quark degrees of freedom and takes into account the transition of chiral symmetry restoration as well as the deconfinement phase transition. At low temperatures $T$ and baryonic densities $\\rho_B$ a hadron resonance gas is described using a SU(3)-flavor sigma-omega model and a quark phase is introduced in analogy to PNJL models for higher $T$ and $\\rho_B$. In this way, the correct asymptotic degrees of freedom are used in a wide range of $T$ and $\\rho_B$. Here, results of this model concerning the chiral and deconfinement phase transitions and thermodynamic model properties are presented. Large hadron resonance multiplicities in the transition region emphasize the importance of heavy-mass resonance states in this region and their impact on the chiral transition behavior. The resulting phase diagram of QCD matter at small chemical potentials is in line with latest lattic...
A full model for simulation of electrochemical cells including complex behavior
Esperilla, J. J.; Félez, J.; Romero, G.; Carretero, A.
This communication presents a model of electrochemical cells developed in order to simulate their electrical, chemical and thermal behavior showing the differences when thermal effects are or not considered in the charge-discharge process. The work presented here has been applied to the particular case of the Pb,PbSO 4|H 2SO 4 (aq)|PbO 2,Pb cell, which forms the basis of the lead-acid batteries so widely used in the automotive industry and as traction batteries in electric or hybrid vehicles. Each half-cell is considered independently in the model. For each half-cell, in addition to the main electrode reaction, a secondary reaction is considered: the hydrogen evolution reaction in the negative electrode and the oxygen evolution reaction in the positive. The equilibrium potential is calculated with the Nernst equation, in which the activity coefficients are fitted to an exponential function using experimental data. On the other hand, the two main mechanisms that produce the overpotential are considered, that is the activation or charge transfer and the diffusion mechanisms. First, an isothermal model has been studied in order to show the behavior of the main phenomena. A more complex model has also been studied including thermal behavior. This model is very useful in the case of traction batteries in electric and hybrid vehicles where high current intensities appear. Some simulation results are also presented in order to show the accuracy of the proposed models.
A High-Rate, Single-Crystal Model including Phase Transformations, Plastic Slip, and Twinning
Energy Technology Data Exchange (ETDEWEB)
Addessio, Francis L. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States). Theoretical Division; Bronkhorst, Curt Allan [Los Alamos National Lab. (LANL), Los Alamos, NM (United States). Theoretical Division; Bolme, Cynthia Anne [Los Alamos National Lab. (LANL), Los Alamos, NM (United States). Explosive Science and Shock Physics Division; Brown, Donald William [Los Alamos National Lab. (LANL), Los Alamos, NM (United States). Materials Science and Technology Division; Cerreta, Ellen Kathleen [Los Alamos National Lab. (LANL), Los Alamos, NM (United States). Materials Science and Technology Division; Lebensohn, Ricardo A. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States). Materials Science and Technology Division; Lookman, Turab [Los Alamos National Lab. (LANL), Los Alamos, NM (United States). Theoretical Division; Luscher, Darby Jon [Los Alamos National Lab. (LANL), Los Alamos, NM (United States). Theoretical Division; Mayeur, Jason Rhea [Los Alamos National Lab. (LANL), Los Alamos, NM (United States). Theoretical Division; Morrow, Benjamin M. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States). Materials Science and Technology Division; Rigg, Paulo A. [Washington State Univ., Pullman, WA (United States). Dept. of Physics. Inst. for Shock Physics
2016-08-09
An anisotropic, rate-dependent, single-crystal approach for modeling materials under the conditions of high strain rates and pressures is provided. The model includes the effects of large deformations, nonlinear elasticity, phase transformations, and plastic slip and twinning. It is envisioned that the model may be used to examine these coupled effects on the local deformation of materials that are subjected to ballistic impact or explosive loading. The model is formulated using a multiplicative decomposition of the deformation gradient. A plate impact experiment on a multi-crystal sample of titanium was conducted. The particle velocities at the back surface of three crystal orientations relative to the direction of impact were measured. Molecular dynamics simulations were conducted to investigate the details of the high-rate deformation and pursue issues related to the phase transformation for titanium. Simulations using the single crystal model were conducted and compared to the high-rate experimental data for the impact loaded single crystals. The model was found to capture the features of the experiments.
A 3D model of the oculomotor plant including the pulley system
Energy Technology Data Exchange (ETDEWEB)
Viegener, A; Armentano, R L [Fundacion Universitaria Dr. Rene G. Favaloro, SolIs 453 (1078) Buenos Aires (Argentina)
2007-11-15
Early models of the oculomotor plant only considered the eye globes and the muscles that move them. Recently, connective tissue structures have been found enveloping the extraocular muscles (EOMs) and firmly anchored to the orbital wall. These structures act as pulleys; they determine the functional origin of the EOMs and, in consequence, their effective pulling direction. A three dimensional model of the oculomotor plant, including pulleys, has been developed and simulations in Simulink were performed during saccadic eye movements. Listing's law was implemented based on the supposition that there exists an eye orientation related signal. The inclusion of the pulleys in the model makes this assumption plausible and simplifies the problem of the plant noncommutativity.
A flexible and qualitatively stable model for cell cycle dynamics including DNA damage effects.
Jeffries, Clark D; Johnson, Charles R; Zhou, Tong; Simpson, Dennis A; Kaufmann, William K
2012-01-01
This paper includes a conceptual framework for cell cycle modeling into which the experimenter can map observed data and evaluate mechanisms of cell cycle control. The basic model exhibits qualitative stability, meaning that regardless of magnitudes of system parameters its instances are guaranteed to be stable in the sense that all feasible trajectories converge to a certain trajectory. Qualitative stability can also be described by the signs of real parts of eigenvalues of the system matrix. On the biological side, the resulting model can be tuned to approximate experimental data pertaining to human fibroblast cell lines treated with ionizing radiation, with or without disabled DNA damage checkpoints. Together these properties validate a fundamental, first order systems view of cell dynamics. Classification Codes: 15A68.
RELAP5-3D Code Includes Athena Features and Models
Energy Technology Data Exchange (ETDEWEB)
Richard A. Riemke; Cliff B. Davis; Richard R. Schultz
2006-07-01
Version 2.3 of the RELAP5-3D computer program includes all features and models previously available only in the ATHENA version of the code. These include the addition of new working fluids (i.e., ammonia, blood, carbon dioxide, glycerol, helium, hydrogen, lead-bismuth, lithium, lithium-lead, nitrogen, potassium, sodium, and sodium-potassium) and a magnetohydrodynamic model that expands the capability of the code to model many more thermal-hydraulic systems. In addition to the new working fluids along with the standard working fluid water, one or more noncondensable gases (e.g., air, argon, carbon dioxide, carbon monoxide, helium, hydrogen, krypton, nitrogen, oxygen, sf6, xenon) can be specified as part of the vapor/gas phase of the working fluid. These noncondensable gases were in previous versions of RELAP5- 3D. Recently four molten salts have been added as working fluids to RELAP5-3D Version 2.4, which has had limited release. These molten salts will be in RELAP5-3D Version 2.5, which will have a general release like RELAP5-3D Version 2.3. Applications that use these new features and models are discussed in this paper.
Including policy and management in socio-hydrology models: initial conceptualizations
Hermans, Leon; Korbee, Dorien
2017-04-01
Socio-hydrology studies the interactions in coupled human-water systems. So far, the use of dynamic models that capture the direct feedback between societal and hydrological systems has been dominant. What has not yet been included with any particular emphasis, is the policy or management layer, which is a central element in for instance integrated water resources management (IWRM) or adaptive delta management (ADM). Studying the direct interactions between human-water systems generates knowledges that eventually helps influence these interactions in ways that may ensure better outcomes - for society and for the health and sustainability of water systems. This influence sometimes occurs through spontaneous emergence, uncoordinated by societal agents - private sector, citizens, consumers, water users. However, the term 'management' in IWRM and ADM also implies an additional coordinated attempt through various public actors. This contribution is a call to include the policy and management dimension more prominently into the research focus of the socio-hydrology field, and offers first conceptual variables that should be considered in attempts to include this policy or management layer in socio-hydrology models. This is done by drawing on existing frameworks to study policy processes throughout both planning and implementation phases. These include frameworks such as the advocacy coalition framework, collective learning and policy arrangements, which all emphasis longer-term dynamics and feedbacks between actor coalitions in strategic planning and implementation processes. A case about longter-term dynamics in the management of the Haringvliet in the Netherlands is used to illustrate the paper.
EXACT SOLUTIONS FOR NONLINEAR TRANSIENT FLOW MODEL INCLUDING A QUADRATIC GRADIENT TERM
Institute of Scientific and Technical Information of China (English)
曹绪龙; 同登科; 王瑞和
2004-01-01
The models of the nonlinear radial flow for the infinite and finite reservoirs including a quadratic gradient term were presented. The exact solution was given in real space for flow equation including quadratic gradiet term for both constant-rate and constant pressure production cases in an infinite system by using generalized Weber transform. Analytical solutions for flow equation including quadratic gradient term were also obtained by using the Hankel transform for a finite circular reservoir case. Both closed and constant pressure outer boundary conditions are considered. Moreover, both constant rate and constant pressure inner boundary conditions are considered. The difference between the nonlinear pressure solution and linear pressure solution is analyzed. The difference may be reached about 8% in the long time. The effect of the quadratic gradient term in the large time well test is considered.
SPheno 3.1: extensions including flavour, CP-phases and models beyond the MSSM
Porod, W.; Staub, F.
2012-11-01
We describe recent extensions of the program SPhenoincluding flavour aspects, CP-phases, R-parity violation and low energy observables. In case of flavour mixing all masses of supersymmetric particles are calculated including the complete flavour structure and all possible CP-phases at the 1-loop level. We give details on implemented seesaw models, low energy observables and the corresponding extension of the SUSY Les Houches Accord. Moreover, we comment on the possibilities to include MSSM extensions in SPheno. Catalogue identifier: ADRV_v2_0 Program summary URL:http://cpc.cs.qub.ac.uk/summaries/ADRV_v2_0.html Program obtainable from: CPC Program Library, Queen’s University, Belfast, N. Ireland Licensing provisions: Standard CPC licence, http://cpc.cs.qub.ac.uk/licence/licence.html No. of lines in distributed program, including test data, etc.: 154062 No. of bytes in distributed program, including test data, etc.: 1336037 Distribution format: tar.gz Programming language: Fortran95. Computer: PC running under Linux, should run in every Unix environment. Operating system: Linux, Unix. Classification: 11.6. Catalogue identifier of previous version: ADRV_v1_0 Journal reference of previous version: Comput. Phys. Comm. 153(2003)275 Does the new version supersede the previous version?: Yes Nature of problem: The first issue is the determination of the masses and couplings of supersymmetric particles in various supersymmetric models, the R-parity conserved MSSM with generation mixing and including CP-violating phases, various seesaw extensions of the MSSM and the MSSM with bilinear R-parity breaking. Low energy data on Standard Model fermion masses, gauge couplings and electroweak gauge boson masses serve as constraints. Radiative corrections from supersymmetric particles to these inputs must be calculated. Theoretical constraints on the soft SUSY breaking parameters from a high scale theory are imposed and the parameters at the electroweak scale are obtained from the
Dong, Minghao; Li, Jun; Shi, Xinfa; Gao, Shudan; Fu, Shijun; Liu, Zongquan; Liang, Fanrong; Gong, Qiyong; Shi, Guangming; Tian, Jie
2015-01-01
It is well established that expertise modulates evoked brain activity in response to specific stimuli. Recently, researchers have begun to investigate how expertise influences the resting brain. Among these studies, most focused on the connectivity features within/across regions, i.e., connectivity patterns/strength. However, little concern has been given to a more fundamental issue whether or not expertise modulates baseline brain activity. We investigated this question using amplitude of low-frequency (expertise model, i.e., acupuncturists, due to their robust proficiency in tactile perception and emotion regulation. After the psychophysical and behavioral expertise screening procedure, 23 acupuncturists and 23 matched non-acupuncturists (NA) were enrolled. Our results explicated higher ALFF for acupuncturists in the left ventral medial prefrontal cortex (VMPFC) and the contralateral hand representation of the primary somatosensory area (SI) (corrected for multiple comparisons). Additionally, ALFF of VMPFC was negatively correlated with the outcomes of the emotion regulation task (corrected for multiple comparisons). We suggest that our study may reveal a novel connection between the neuroplasticity mechanism and resting state activity, which would upgrade our understanding of the central mechanism of learning. Furthermore, by showing that expertise can affect the baseline brain activity as indicated by ALFF, our findings may have profound implication for functional neuroimaging studies especially those involving expert models, in that difference in baseline brain activity may either smear the spatial pattern of activations for task data or introduce biased results into connectivity-based analysis for resting data.
Venetsanos, A G; Bartzis, J G; Würtz, J; Papailiou, D D
2003-04-25
A two-dimensional shallow layer model has been developed to predict dense gas dispersion, under realistic conditions, including complex features such as two-phase releases, obstacles and inclined ground. The model attempts to predict the time and space evolution of the cloud formed after a release of a two-phase pollutant into the atmosphere. The air-pollutant mixture is assumed ideal. The cloud evolution is described mathematically through the Cartesian, two-dimensional, shallow layer conservation equations for mixture mass, mixture momentum in two horizontal directions, total pollutant mass fraction (vapor and liquid) and mixture internal energy. Liquid mass fraction is obtained assuming phase equilibrium. Account is taken in the conservation equations for liquid slip and eventual liquid rainout through the ground. Entrainment of ambient air is modeled via an entrainment velocity model, which takes into account the effects of ground friction, ground heat transfer and relative motion between cloud and surrounding atmosphere. The model additionally accounts for thin obstacles effects in three ways. First a stepwise description of the obstacle is generated, following the grid cell faces, taking into account the corresponding area blockage. Then obstacle drag on the passing cloud is modeled by adding flow resistance terms in the momentum equations. Finally the effect of extra vorticity generation and entrainment enhancement behind obstacles is modeled by adding locally into the entrainment formula without obstacles, a characteristic velocity scale defined from the obstacle pressure drop and the local cloud height.The present model predictions have been compared against theoretical results for constant volume and constant flux gravity currents. It was found that deviations of the predicted cloud footprint area change with time from the theoretical were acceptably small, if one models the frictional forces between cloud and ambient air, neglecting the Richardson
Stolarski, R. S.; Douglass, A. R.
1986-01-01
Models of stratospheric photochemistry are generally tested by comparing their predictions for the composition of the present atmosphere with measurements of species concentrations. These models are then used to make predictions of the atmospheric sensitivity to perturbations. Here the problem of the sensitivity of such a model to chlorine perturbations ranging from the present influx of chlorine-containing compounds to several times that influx is addressed. The effects of uncertainties in input parameters, including reaction rate coefficients, cross sections, solar fluxes, and boundary conditions, are evaluated using a Monte Carlo method in which the values of the input parameters are randomly selected. The results are probability distributions for present atmosheric concentrations and for calculated perturbations due to chlorine from fluorocarbons. For more than 300 Monte Carlo runs the calculated ozone perturbation for continued emission of fluorocarbons at today's rates had a mean value of -6.2 percent, with a 1-sigma width of 5.5 percent. Using the same runs but only allowing the cases in which the calculated present atmosphere values of NO, NO2, and ClO at 25 km altitude fell within the range of measurements yielded a mean ozone depletion of -3 percent, with a 1-sigma deviation of 2.2 percent. The model showed a nonlinear behavior as a function of added fluorocarbons. The mean of the Monte Carlo runs was less nonlinear than the model run using mean value of the input parameters.
Kim, Sun Jung; Yoo, Il Young
2016-03-01
The purpose of this study was to explain the health promotion behavior of Chinese international students in Korea using a structural equation model including acculturation factors. A survey using self-administered questionnaires was employed. Data were collected from 272 Chinese students who have resided in Korea for longer than 6 months. The data were analyzed using structural equation modeling. The p value of final model is .31. The fitness parameters of the final model such as goodness of fit index, adjusted goodness of fit index, normed fit index, non-normed fit index, and comparative fit index were more than .95. Root mean square of residual and root mean square error of approximation also met the criteria. Self-esteem, perceived health status, acculturative stress and acculturation level had direct effects on health promotion behavior of the participants and the model explained 30.0% of variance. The Chinese students in Korea with higher self-esteem, perceived health status, acculturation level, and lower acculturative stress reported higher health promotion behavior. The findings can be applied to develop health promotion strategies for this population. Copyright © 2016. Published by Elsevier B.V.
S5-4: Formal Modeling of Affordance in Human-Included Systems
Directory of Open Access Journals (Sweden)
Namhun Kim
2012-10-01
Full Text Available In spite of it being necessary for humans to consider modeling, analysis, and control of human-included systems, it has been considered a challenging problem because of the critical role of humans in complex systems and of humans' capability of executing unanticipated actions–both beneficial and detrimental ones. Thus, to provide systematic approaches to modeling human actions as a part of system behaviors, a formal modeling framework for human-involved systems in which humans play a controlling role based on their perceptual information is presented. The theory of affordance provides definitions of human actions and their associated properties; Finite State Automata (FSA based modeling is capable of mapping nondeterministic humans into computable components in the system representation. In this talk, we investigate the role of perception in human actions in the system operation and examine the representation of perceptual elements in affordance-based modeling formalism. The proposed framework is expected to capture the natural ways in which humans participate in the system as part of its operation. A human-machine cooperative manufacturing system control example and a human agent simulation example will be introduced for the illustrative purposes at the end of the presentation.
An extended gene protein/products Boolean network model including post-transcriptional regulation.
Benso, Alfredo; Di Carlo, Stefano; Politano, Gianfranco; Savino, Alessandro; Vasciaveo, Alessandro
2014-05-07
Networks Biology allows the study of complex interactions between biological systems using formal, well structured, and computationally friendly models. Several different network models can be created, depending on the type of interactions that need to be investigated. Gene Regulatory Networks (GRN) are an effective model commonly used to study the complex regulatory mechanisms of a cell. Unfortunately, given their intrinsic complexity and non discrete nature, the computational study of realistic-sized complex GRNs requires some abstractions. Boolean Networks (BNs), for example, are a reliable model that can be used to represent networks where the possible state of a node is a boolean value (0 or 1). Despite this strong simplification, BNs have been used to study both structural and dynamic properties of real as well as randomly generated GRNs. In this paper we show how it is possible to include the post-transcriptional regulation mechanism (a key process mediated by small non-coding RNA molecules like the miRNAs) into the BN model of a GRN. The enhanced BN model is implemented in a software toolkit (EBNT) that allows to analyze boolean GRNs from both a structural and a dynamic point of view. The open-source toolkit is compatible with available visualization tools like Cytoscape and allows to run detailed analysis of the network topology as well as of its attractors, trajectories, and state-space. In the paper, a small GRN built around the mTOR gene is used to demonstrate the main capabilities of the toolkit. The extended model proposed in this paper opens new opportunities in the study of gene regulation. Several of the successful researches done with the support of BN to understand high-level characteristics of regulatory networks, can now be improved to better understand the role of post-transcriptional regulation for example as a network-wide noise-reduction or stabilization mechanisms.
An extended gene protein/products boolean network model including post-transcriptional regulation
2014-01-01
Background Networks Biology allows the study of complex interactions between biological systems using formal, well structured, and computationally friendly models. Several different network models can be created, depending on the type of interactions that need to be investigated. Gene Regulatory Networks (GRN) are an effective model commonly used to study the complex regulatory mechanisms of a cell. Unfortunately, given their intrinsic complexity and non discrete nature, the computational study of realistic-sized complex GRNs requires some abstractions. Boolean Networks (BNs), for example, are a reliable model that can be used to represent networks where the possible state of a node is a boolean value (0 or 1). Despite this strong simplification, BNs have been used to study both structural and dynamic properties of real as well as randomly generated GRNs. Results In this paper we show how it is possible to include the post-transcriptional regulation mechanism (a key process mediated by small non-coding RNA molecules like the miRNAs) into the BN model of a GRN. The enhanced BN model is implemented in a software toolkit (EBNT) that allows to analyze boolean GRNs from both a structural and a dynamic point of view. The open-source toolkit is compatible with available visualization tools like Cytoscape and allows to run detailed analysis of the network topology as well as of its attractors, trajectories, and state-space. In the paper, a small GRN built around the mTOR gene is used to demonstrate the main capabilities of the toolkit. Conclusions The extended model proposed in this paper opens new opportunities in the study of gene regulation. Several of the successful researches done with the support of BN to understand high-level characteristics of regulatory networks, can now be improved to better understand the role of post-transcriptional regulation for example as a network-wide noise-reduction or stabilization mechanisms. PMID:25080304
Mohammad, S. Noor
2010-09-01
Semiconductor nanotubes, including carbon nanotubes, have vast potential for new technology development. The fundamental physics and growth kinetics of these nanotubes are still obscured. Various models developed to elucidate the growth suffer from limited applicability. An in-depth investigation of the fundamentals of nanotube growth has, therefore, been carried out. For this investigation, various features of nanotube growth, and the role of the foreign element catalytic agent (FECA) in this growth, have been considered. Observed growth anomalies have been analyzed. Based on this analysis, a new shell model and a general hypothesis have been proposed for the growth. The essential element of the shell model is the seed generated from segregation during growth. The seed structure has been defined, and the formation of droplet from this seed has been described. A modified definition of the droplet exhibiting adhesive properties has also been presented. Various characteristics of the droplet, required for alignment and organization of atoms into tubular forms, have been discussed. Employing the shell model, plausible scenarios for the formation of carbon nanotubes, and the variation in the characteristics of these carbon nanotubes have been articulated. The experimental evidences, for example, for the formation of shell around a core, dipole characteristics of the seed, and the existence of nanopores in the seed, have been presented. They appear to justify the validity of the proposed model. The diversities of nanotube characteristics, fundamentals underlying the creation of bamboo-shaped carbon nanotubes, and the impurity generation on the surface of carbon nanotubes have been elucidated. The catalytic action of FECA on growth has been quantified. The applicability of the proposed model to the nanotube growth by a variety of mechanisms has been elaborated. These mechanisms include the vapor-liquid-solid mechanism, the oxide-assisted growth mechanism, the self
Analysis of electronic models for solar cells including energy resolved defect densities
Energy Technology Data Exchange (ETDEWEB)
Glitzky, Annegret
2010-07-01
We introduce an electronic model for solar cells including energy resolved defect densities. The resulting drift-diffusion model corresponds to a generalized van Roosbroeck system with additional source terms coupled with ODEs containing space and energy as parameters for all defect densities. The system has to be considered in heterostructures and with mixed boundary conditions from device simulation. We give a weak formulation of the problem. If the boundary data and the sources are compatible with thermodynamic equilibrium the free energy along solutions decays monotonously. In other cases it may be increasing, but we estimate its growth. We establish boundedness and uniqueness results and prove the existence of a weak solution. This is done by considering a regularized problem, showing its solvability and the boundedness of its solutions independent of the regularization level. (orig.)
Nonlinear Acoustics FDTD method including Frequency Power Law Attenuation for Soft Tissue Modeling
Jiménez, Noé; Sánchez-Morcillo, Víctor; Camarena, Francisco; Hou, Yi; Konofagou, Elisa E
2014-01-01
This paper describes a model for nonlinear acoustic wave propagation through absorbing and weakly dispersive media, and its numerical solution by means of finite differences in time domain method (FDTD). The attenuation is based on multiple relaxation processes, and provides frequency dependent absorption and dispersion without using computational expensive convolutional operators. In this way, by using an optimization algorithm the coefficients for the relaxation processes can be obtained in order to fit a frequency power law that agrees the experimentally measured attenuation data for heterogeneous media over the typical frequency range for ultrasound medical applications. Our results show that two relaxation processes are enough to fit attenuation data for most soft tissues in this frequency range including the fundamental and the first ten harmonics. Furthermore, this model can fit experimental attenuation data that do not follow exactly a frequency power law over the frequency range of interest. The main...
Particle-based modeling of heterogeneous chemical kinetics including mass transfer
Sengar, A.; Kuipers, J. A. M.; van Santen, Rutger A.; Padding, J. T.
2017-08-01
Connecting the macroscopic world of continuous fields to the microscopic world of discrete molecular events is important for understanding several phenomena occurring at physical boundaries of systems. An important example is heterogeneous catalysis, where reactions take place at active surfaces, but the effective reaction rates are determined by transport limitations in the bulk fluid and reaction limitations on the catalyst surface. In this work we study the macro-micro connection in a model heterogeneous catalytic reactor by means of stochastic rotation dynamics. The model is able to resolve the convective and diffusive interplay between participating species, while including adsorption, desorption, and reaction processes on the catalytic surface. Here we apply the simulation methodology to a simple straight microchannel with a catalytic strip. Dimensionless Damkohler numbers are used to comment on the spatial concentration profiles of reactants and products near the catalyst strip and in the bulk. We end the discussion with an outlook on more complicated geometries and increasingly complex reactions.
Models of epidemics: when contact repetition and clustering should be included
Directory of Open Access Journals (Sweden)
Scholz Roland W
2009-06-01
Full Text Available Abstract Background The spread of infectious disease is determined by biological factors, e.g. the duration of the infectious period, and social factors, e.g. the arrangement of potentially contagious contacts. Repetitiveness and clustering of contacts are known to be relevant factors influencing the transmission of droplet or contact transmitted diseases. However, we do not yet completely know under what conditions repetitiveness and clustering should be included for realistically modelling disease spread. Methods We compare two different types of individual-based models: One assumes random mixing without repetition of contacts, whereas the other assumes that the same contacts repeat day-by-day. The latter exists in two variants, with and without clustering. We systematically test and compare how the total size of an outbreak differs between these model types depending on the key parameters transmission probability, number of contacts per day, duration of the infectious period, different levels of clustering and varying proportions of repetitive contacts. Results The simulation runs under different parameter constellations provide the following results: The difference between both model types is highest for low numbers of contacts per day and low transmission probabilities. The number of contacts and the transmission probability have a higher influence on this difference than the duration of the infectious period. Even when only minor parts of the daily contacts are repetitive and clustered can there be relevant differences compared to a purely random mixing model. Conclusion We show that random mixing models provide acceptable estimates of the total outbreak size if the number of contacts per day is high or if the per-contact transmission probability is high, as seen in typical childhood diseases such as measles. In the case of very short infectious periods, for instance, as in Norovirus, models assuming repeating contacts will also behave
Boullata, Joseph I; Holcombe, Beverly; Sacks, Gordon; Gervasio, Jane; Adams, Stephen C; Christensen, Michael; Durfee, Sharon; Ayers, Phil; Marshall, Neil; Guenter, Peggi
2016-08-01
Parenteral nutrition (PN) is a high-alert medication with a complex drug use process. Key steps in the process include the review of each PN prescription followed by the preparation of the formulation. The preparation step includes compounding the PN or activating a standardized commercially available PN product. The verification and review, as well as preparation of this complex therapy, require competency that may be determined by using a standardized process for pharmacists and for pharmacy technicians involved with PN. An American Society for Parenteral and Enteral Nutrition (ASPEN) standardized model for PN order review and PN preparation competencies is proposed based on a competency framework, the ASPEN-published interdisciplinary core competencies, safe practice recommendations, and clinical guidelines, and is intended for institutions and agencies to use with their staff.
A generalized model for optimal transport of images including dissipation and density modulation
Maas, Jan
2015-11-01
© EDP Sciences, SMAI 2015. In this paper the optimal transport and the metamorphosis perspectives are combined. For a pair of given input images geodesic paths in the space of images are defined as minimizers of a resulting path energy. To this end, the underlying Riemannian metric measures the rate of transport cost and the rate of viscous dissipation. Furthermore, the model is capable to deal with strongly varying image contrast and explicitly allows for sources and sinks in the transport equations which are incorporated in the metric related to the metamorphosis approach by Trouvé and Younes. In the non-viscous case with source term existence of geodesic paths is proven in the space of measures. The proposed model is explored on the range from merely optimal transport to strongly dissipative dynamics. For this model a robust and effective variational time discretization of geodesic paths is proposed. This requires to minimize a discrete path energy consisting of a sum of consecutive image matching functionals. These functionals are defined on corresponding pairs of intensity functions and on associated pairwise matching deformations. Existence of time discrete geodesics is demonstrated. Furthermore, a finite element implementation is proposed and applied to instructive test cases and to real images. In the non-viscous case this is compared to the algorithm proposed by Benamou and Brenier including a discretization of the source term. Finally, the model is generalized to define discrete weighted barycentres with applications to textures and objects.
Yoshihara, Lena; Roth, Christian J; Wall, Wolfgang A
2017-04-01
In this article, a novel approach is presented for combining standard fluid-structure interaction with additional volumetric constraints to model fluid flow into and from homogenised solid domains. The proposed algorithm is particularly interesting for investigations in the field of respiratory mechanics as it enables the mutual coupling of airflow in the conducting part and local tissue deformation in the respiratory part of the lung by means of a volume constraint. In combination with a classical monolithic fluid-structure interaction approach, a comprehensive model of the human lung can be established that will be useful to gain new insights into respiratory mechanics in health and disease. To illustrate the validity and versatility of the novel approach, three numerical examples including a patient-specific lung model are presented. The proposed algorithm proves its capability of computing clinically relevant airflow distribution and tissue strain data at a level of detail that is not yet achievable, neither with current imaging techniques nor with existing computational models. Copyright © 2016 John Wiley & Sons, Ltd. Copyright © 2016 John Wiley & Sons, Ltd.
Empirical Validation of a Thermal Model of a Complex Roof Including Phase Change Materials
Directory of Open Access Journals (Sweden)
Stéphane Guichard
2015-12-01
Full Text Available This paper deals with the empirical validation of a building thermal model of a complex roof including a phase change material (PCM. A mathematical model dedicated to PCMs based on the heat apparent capacity method was implemented in a multi-zone building simulation code, the aim being to increase the understanding of the thermal behavior of the whole building with PCM technologies. In order to empirically validate the model, the methodology is based both on numerical and experimental studies. A parametric sensitivity analysis was performed and a set of parameters of the thermal model has been identified for optimization. The use of the generic optimization program called GenOpt® coupled to the building simulation code enabled to determine the set of adequate parameters. We first present the empirical validation methodology and main results of previous work. We then give an overview of GenOpt® and its coupling with the building simulation code. Finally, once the optimization results are obtained, comparisons of the thermal predictions with measurements are found to be acceptable and are presented.
Habitability of super-Earth planets around other suns: models including Red Giant Branch evolution.
von Bloh, W; Cuntz, M; Schröder, K-P; Bounama, C; Franck, S
2009-01-01
The unexpected diversity of exoplanets includes a growing number of super-Earth planets, i.e., exoplanets with masses of up to several Earth masses and a similar chemical and mineralogical composition as Earth. We present a thermal evolution model for a 10 Earth-mass planet orbiting a star like the Sun. Our model is based on the integrated system approach, which describes the photosynthetic biomass production and takes into account a variety of climatological, biogeochemical, and geodynamical processes. This allows us to identify a so-called photosynthesis-sustaining habitable zone (pHZ), as determined by the limits of biological productivity on the planetary surface. Our model considers solar evolution during the main-sequence stage and along the Red Giant Branch as described by the most recent solar model. We obtain a large set of solutions consistent with the principal possibility of life. The highest likelihood of habitability is found for "water worlds." Only mass-rich water worlds are able to realize pHZ-type habitability beyond the stellar main sequence on the Red Giant Branch.
A transient energy function for power systems including the induction motor model
Institute of Scientific and Technical Information of China (English)
无
2007-01-01
A construction method for power system transient energy function is studied in the paper, which is simple and universal, and can unify the forms of some current energy functions. A transient energy function including the induction motor model is derived using the method. The unintegrable term is dealt with to get an approximate energy function. Simulations in a 3-bus system and in the WSCC 4-generator system verify the validity of the proposed energy function. The function can be applied to direct transient stability analysis of multi-machine large power systems and provides a tool for analysis of the interaction between the generator angle stability and the load voltage stability.
A laboratory model of the aortic root flow including the coronary arteries
Querzoli, Giorgio; Fortini, Stefania; Espa, Stefania; Melchionna, Simone
2016-08-01
Cardiovascular flows have been extensively investigated by means of in vitro models to assess the prosthetic valve performances and to provide insight into the fluid dynamics of the heart and proximal aorta. In particular, the models for the study of the flow past the aortic valve have been continuously improved by including, among other things, the compliance of the vessel and more realistic geometries. The flow within the sinuses of Valsalva is known to play a fundamental role in the dynamics of the aortic valve since they host a recirculation region that interacts with the leaflets. The coronary arteries originate from the ostia located within two of the three sinuses, and their presence may significantly affect the fluid dynamics of the aortic root. In spite of their importance, to the extent of the authors' knowledge, coronary arteries were not included so far when modeling in vitro the transvalvular aortic flow. We present a pulse duplicator consisting of a passively pulsing ventricle, a compliant proximal aorta, and coronary arteries connected to the sinuses of Valsalva. The coronary flow is modulated by a self-regulating device mimicking the physiological mechanism, which is based on the contraction and relaxation of the heart muscle during the cardiac cycle. Results show that the model reproduces satisfyingly the coronary flow. The analysis of the time evolution of the velocity and vorticity fields within the aortic root reveals the main characteristics of the backflow generated through the aorta in order to feed the coronaries during the diastole. Experiments without coronary flow have been run for comparison. Interestingly, the lifetime of the vortex forming in the sinus of Valsalva during the systole is reduced by the presence of the coronaries. As a matter of fact, at the end of the systole, that vortex is washed out because of the suction generated by the coronary flow. Correspondingly, the valve closure is delayed and faster compared to the case with
Including sugar cane in the agro-ecosystem model ORCHIDEE-STICS
Valade, A.; Vuichard, N.; Ciais, P.; Viovy, N.
2010-12-01
With 4 million ha currently grown for ethanol in Brazil only, approximately half the global bioethanol production in 2005 (Smeets 2008), and a devoted land area expected to expand globally in the years to come, sugar cane is at the heart of the biofuel debate. Indeed, ethanol made from biomass is currently the most widespread option for alternative transportation fuels. It was originally promoted as a carbon neutral energy resource that could bring energy independence to countries and local opportunities to farmers, until attention was drawn to its environmental and socio-economical drawbacks. It is still not clear to which extent it is a solution or a contributor to climate change mitigation. Dynamic Global Vegetation models can help address these issues and quantify the potential impacts of biofuels on ecosystems at scales ranging from on-site to global. The global agro-ecosystem model ORCHIDEE describes water, carbon and energy exchanges at the soil-atmosphere interface for a limited number of natural and agricultural vegetation types. In order to integrate agricultural management to the simulations and to capture more accurately the specificity of crops' phenology, ORCHIDEE has been coupled with the agronomical model STICS. The resulting crop-oriented vegetation model ORCHIDEE-STICS has been used so far to simulate temperate crops such as wheat, corn and soybean. As a generic ecosystem model, each grid cell can include several vegetation types with their own phenology and management practices, making it suitable to spatial simulations. Here, ORCHIDEE-STICS is altered to include sugar cane as a new agricultural Plant functional Type, implemented and parametrized using the STICS approach. An on-site calibration and validation is then performed based on biomass and flux chamber measurements in several sites in Australia and variables such as LAI, dry weight, heat fluxes and respiration are used to evaluate the ability of the model to simulate the specific
Rivas, Elena; Lang, Raymond; Eddy, Sean R
2012-02-01
The standard approach for single-sequence RNA secondary structure prediction uses a nearest-neighbor thermodynamic model with several thousand experimentally determined energy parameters. An attractive alternative is to use statistical approaches with parameters estimated from growing databases of structural RNAs. Good results have been reported for discriminative statistical methods using complex nearest-neighbor models, including CONTRAfold, Simfold, and ContextFold. Little work has been reported on generative probabilistic models (stochastic context-free grammars [SCFGs]) of comparable complexity, although probabilistic models are generally easier to train and to use. To explore a range of probabilistic models of increasing complexity, and to directly compare probabilistic, thermodynamic, and discriminative approaches, we created TORNADO, a computational tool that can parse a wide spectrum of RNA grammar architectures (including the standard nearest-neighbor model and more) using a generalized super-grammar that can be parameterized with probabilities, energies, or arbitrary scores. By using TORNADO, we find that probabilistic nearest-neighbor models perform comparably to (but not significantly better than) discriminative methods. We find that complex statistical models are prone to overfitting RNA structure and that evaluations should use structurally nonhomologous training and test data sets. Overfitting has affected at least one published method (ContextFold). The most important barrier to improving statistical approaches for RNA secondary structure prediction is the lack of diversity of well-curated single-sequence RNA secondary structures in current RNA databases.
Chen, Chang-Kun; Li, Zhi; Sun, Yun-Feng
A new model for describing the disaster system including instantaneous and continuous action synchronously has been developed. The model is composed of three primary parts, that is, the impact from its causative disaster events, stochastic noise of disaster node and self-healing function, and every part is modeled concretely in terms of their characteristics in practice. Some key parameters, namely link appearance probability, retardation coefficient, ultimate repair capacity of government, dynamical modes considering different disaster evolving chains, and the positions of link with the specific performance in disaster network system are involved. Combined with a case study, the proposed model is applied to a certain disaster evolution system, and the influence law of different parameters on disaster evolution process, in disaster networks with instantaneous-action and/or continuous-action, is presented and compared. The results indicate that the destructive impact in the networks by link in continuous action is far greater an order of magnitude than that in instantaneous action. If a link in continuous action emerges in the disaster network system, properties of the causative event for the link, link appearance probability and its position in the network all have a notable influence to the severity of the disaster network. In addition, some peculiar phenomena are also commendably observed in the disaster evolution process based on the model, such as the multipeaks emerging in the destroyed rate number curve for some crisis nodes caused by their various inducing paths together with the relevant retardation coefficients, the existence of the critical value for ultimate repair capacity to recover the disaster node, and so on.
Moreau, Caroline; Pautas, Eric; Duverlie, Charlotte; Berndt, Celia; Andro, Marion; Mahé, Isabelle; Emmerich, Joseph; Lacut, Karine; Le Gal, Grégoire; Peyron, Isabelle; Gouin-Thibault, Isabelle; Golmard, Jean-Louis; Loriot, Marie-Anne; Siguret, Virginie
2014-04-01
Indandione VKAs have been widely used for decades, especially in Eastern Europe and France. Contrary to coumarin VKAs, the relative contribution of individual factors to the indandione-VKA response is poorly known. In the present multicentre study, we sought to develop and validate a model including genetic and non-genetic factors to predict the daily fluindione dose requirement in elderly patients in whom VKA dosing is challenging. We prospectively recorded clinical and therapeutic data in 230 Caucasian inpatients mean aged 85 ± 6 years, who had reached international normalized ratio stabilisation (range 2.0-3.0) on fluindione. In the derivation cohort (n=156), we analysed 13 polymorphisms in seven genes potentially involved in the pharmacological effect or vitamin-K cycle (VKORC1, CYP4F2, EPHX1) and fluindione metabolism/transport (CYP2C9, CYP2C19, CYP3A5, ABCB1). We built a regression model incorporating non-genetic and genetic data and evaluated the model performances in a separate cohort (n=74).Body-weight, amiodarone intake, VKORC1, CYP4F2, ABCB1 genotypes were retained in the final model, accounting for 31.5% of dose variability. None influence of CYP2C9 was observed. Our final model showed good performances: in 83.3% of the validation cohort patients, the dose was accurately predicted within 5 mg, i.e.the usual step used for adjusting fluindione dosage. In conclusion, in addition to body-weight and amiodarone-intake, pharmacogenetic factors (VKORC1, CYP4F2, ABCB1) related to the pharmacodynamic effect and transport of fluindione significantly influenced the dose requirement in elderly patients while CYP2C9 did not. Studies are required to know whether fluindione could be an alternative VKA in carriers of polymorphic CYP2C9 alleles, hypersensitive to coumarins.
ISOLATION OF HEPATIC OVAL CELLS FROM DIFFERENT MODEL RATS INCLUDING DIABETIC RATS
Institute of Scientific and Technical Information of China (English)
LU Ying-li; YE Ting-ting; XIA Fang-zhen; WANG Ning-jian; YANG Hua; CHEN Yi
2009-01-01
Objective To acquire oval cells (progenitor stem cells) from adult rat liver of different models including diabetic rats. Methods Thirty Sprague-Dawley (SD) rats were divided into 5 groups randomly: control, 2-acetylaminofluorene (2-AAF), 2-AAF+partial hepatectomy (PH), 2-AAF+carbon tetrachloride (CCl4), and diabetic groups. As two-step collagenase perfusion protocol of Seglen, oval cells were isolated by Percoll density gradient centrifugation. Thy1.1 positive cells were sorted by flow cytometry, and then cultured in Dulbeccos minimum Eagles medium (DMEM). Immunofluorescence staining was applied to labelling Thy1.1. Results Different rates of Thy1.1 positive oval cells were found in different rat model groups: 0.5% in 2-AAF, 0.3% in 2-hAAF+PH, 0.2% in 2-AAF+CCl4 , 0.1% in diabetic, and 0.0% in control. Isolated cells adhered to plate with fusiform or polygon as epithelial cells. Conclusion Progenitor stem cells exist in injured liver tissue including those from diabetic rats.
Dynamic modelling and analysis of multi-machine power systems including wind farms
Tabesh, Ahmadreza
2005-11-01
This thesis introduces a small-signal dynamic model, based on a frequency response approach, for the analysis of a multi-machine power system with special focus on an induction machine based wind farm. The proposed approach is an alternative method to the conventional eigenvalue analysis method which is widely employed for small-signal dynamic analyses of power systems. The proposed modelling approach is successfully applied and evaluated for a power system that (i) includes multiple synchronous generators, and (ii) a wind farm based on either fixed-speed, variable-speed, or doubly-fed induction machine based wind energy conversion units. The salient features of the proposed method, as compared with the conventional eigenvalue analysis method, are: (i) computational efficiency since the proposed method utilizes the open-loop transfer-function matrix of the system, (ii) performance indices that are obtainable based on frequency response data and quantitatively describe the dynamic behavior of the system, and (iii) capability to formulate various wind energy conversion unit, within a wind farm, in a modular form. The developed small-signal dynamic model is applied to a set of multi-machine study systems and the results are validated based on comparison (i) with digital time-domain simulation results obtained from PSCAD/EMTDC software tool, and (ii) where applicable with eigenvalue analysis results.
A Hydrological Concept including Lateral Water Flow Compatible with the Biogeochemical Model ForSAFE
Directory of Open Access Journals (Sweden)
Giuliana Zanchi
2016-03-01
Full Text Available The study presents a hydrology concept developed to include lateral water flow in the biogeochemical model ForSAFE. The hydrology concept was evaluated against data collected at Svartberget in the Vindeln Research Forest in Northern Sweden. The results show that the new concept allows simulation of a saturated and an unsaturated zone in the soil as well as water flow that reaches the stream comparable to measurements. The most relevant differences compared to streamflow measurements are that the model simulates a higher base flow in winter and lower flow peaks after snowmelt. These differences are mainly caused by the assumptions made to regulate the percolation at the bottom of the simulated soil columns. The capability for simulating lateral flows and a saturated zone in ForSAFE can greatly improve the simulation of chemical exchange in the soil and export of elements from the soil to watercourses. Such a model can help improve the understanding of how environmental changes in the forest landscape will influence chemical loads to surface waters.
Modeling within-host dynamics of influenza virus infection including immune responses.
Directory of Open Access Journals (Sweden)
Kasia A Pawelek
Full Text Available Influenza virus infection remains a public health problem worldwide. The mechanisms underlying viral control during an uncomplicated influenza virus infection are not fully understood. Here, we developed a mathematical model including both innate and adaptive immune responses to study the within-host dynamics of equine influenza virus infection in horses. By comparing modeling predictions with both interferon and viral kinetic data, we examined the relative roles of target cell availability, and innate and adaptive immune responses in controlling the virus. Our results show that the rapid and substantial viral decline (about 2 to 4 logs within 1 day after the peak can be explained by the killing of infected cells mediated by interferon activated cells, such as natural killer cells, during the innate immune response. After the viral load declines to a lower level, the loss of interferon-induced antiviral effect and an increased availability of target cells due to loss of the antiviral state can explain the observed short phase of viral plateau in which the viral level remains unchanged or even experiences a minor second peak in some animals. An adaptive immune response is needed in our model to explain the eventual viral clearance. This study provides a quantitative understanding of the biological factors that can explain the viral and interferon kinetics during a typical influenza virus infection.
Kundin, J.; Raabe, D.; Emmerich, H.
2011-10-01
If alloys undergo an incoherent martensitic transformation, then plastic accommodation and relaxation accompany the transformation. To capture these mechanisms we develop an improved 3D microelastic-plastic phase-field model. It is based on the classical concepts of phase-field modeling of microelastic problems (Chen, L.Q., Wang Y., Khachaturyan, A.G., 1992. Philos. Mag. Lett. 65, 15-23). In addition to these it takes into account the incoherent formation of accommodation dislocations in the austenitic matrix, as well as their inheritance into the martensitic plates based on the crystallography of the martensitic transformation. We apply this new phase-field approach to the butterfly-type martensitic transformation in a Fe-30 wt%Ni alloy in direct comparison to recent experimental data (Sato, H., Zaefferer, S., 2009. Acta Mater. 57, 1931-1937). It is shown that the therein proposed mechanisms of plastic accommodation during the transformation can indeed explain the experimentally observed morphology of the martensitic plates as well as the orientation between martensitic plates and the austenitic matrix. The developed phase-field model constitutes a general simulations approach for different kinds of phase transformation phenomena that inherently include dislocation based accommodation processes. The approach does not only predict the final equilibrium topology, misfit, size, crystallography, and aspect ratio of martensite-austenite ensembles resulting from a transformation, but it also resolves the associated dislocation dynamics and the distribution, and the size of the crystals itself.
Thiaw, Modou; Gascuel, Didier; Jouffre, Didier; Thiaw, Omar Thiom
2009-12-01
In Senegal, two stocks of white shrimp ( Penaeusnotialis) are intensively exploited, one in the north and another in the south. We used surplus production models including environmental effects to analyse their changes in abundance over the past 10 years and to estimate their Maximum Sustainable Yield (MSY) and the related fishing effort ( EMSY). First, yearly abundance indices were estimated from commercial statistics using GLM techniques. Then, two environmental indices were alternatively tested in the model: the coastal upwelling intensity from wind speeds provided by the SeaWifs database and the primary production derived from satellite infrared images of chlorophyll a. Models were fitted, with or without the environmental effect, to the 1996-2005 time series. They express stock abundance and catches as functions of the fishing effort and the environmental index (when considered). For the northern stock, fishing effort and abundance fluctuate over the period without any clear trends. The model based on the upwelling index explains 64.9% of the year-to-year variability. It shows that the stock was slightly overexploited in 2002-2003 and is now close to full exploitation. Stock abundance strongly depends on environmental conditions; consequently, the MSY estimate varies from 300 to 900 tons according to the upwelling intensity. For the southern stock, fishing effort has strongly increased over the past 10 years, while abundance has been reduced 4-fold. The environment has a significant effect on abundance but only explains a small part of the year-to-year variability. The best fit is obtained using the primary production index ( R2 = 0.75), and the stock is now significantly overfished regardless of environmental conditions. MSY varies from 1200 to 1800 tons according to environmental conditions. Finally, in northern Senegal, the upwelling is highly variable from year to year and constitutes the major factor determining productivity. In the south, hydrodynamic
Prechtel, Alexander; Ray, Nadja; Rupp, Andreas
2017-04-01
We want to present an approach for the mathematical, mechanistic modeling and numerical treatment of processes leading to the formation, stability, and turnover of soil micro-aggregates. This aims at deterministic aggregation models including detailed mechanistic pore-scale descriptions to account for the interplay of geochemistry and microbiology, and the link to soil functions as, e.g., the porosity. We therefore consider processes at the pore scale and the mesoscale (laboratory scale). At the pore scale transport by diffusion, advection, and drift emerging from electric forces can be taken into account, in addition to homogeneous and heterogeneous reactions of species. In the context of soil micro-aggregates the growth of biofilms or other glueing substances as EPS (extracellular polymeric substances) is important and affects the structure of the pore space in space and time. This model is upscaled mathematically in the framework of (periodic) homogenization to transfer it to the mesoscale resulting in effective coefficients/parameters there. This micro-macro model thus couples macroscopic equations that describe the transport and fluid flow at the scale of the porous medium (mesoscale) with averaged time- and space-dependent coefficient functions. These functions may be explicitly computed by means of auxiliary cell problems (microscale). Finally, the pore space in which the cell problems are defined is time and space dependent and its geometry inherits information from the transport equation's solutions. The microscale problems rely on versatile combinations of cellular automata and discontiuous Galerkin methods while on the mesoscale mixed finite elements are used. The numerical simulations allow to study the interplay between these processes.
Gabrielle, B.; Gagnaire, N.; Massad, R.; Prieur, V.; Python, Y.
2012-04-01
The potential greenhouse gas (GHG) savings resulting from the displacement of fossil energy sources by bioenergy mostly hinges on the uncertainty on the magnitude of nitrous oxide (N2O) emissions from arable soils occuring during feedstock production. These emissions are broadly related to fertilizer nitrogen input rates, but largely controlled by soil and climate factors which makes their estimation highly uncertain. Here, we set out to improve estimates of N2O emissions from bioenergy feedstocks by using ecosystem models and measurements and modeling of atmospheric N2O in the greater Paris (France) area. Ground fluxes were measured in two locations to assess the effect of soil type and management, crop type (including lignocellulosics such as triticale, switchgrass and miscanthus), and climate on N2O emission rates and dynamics. High-resolution maps of N2O emissions were generated over the Ile-de-France region (around Paris) with two ecosystem models using geographical databases on soils, weather data, land-use and crop management. The models were tested against ground flux measurements and the emission maps were fed into the atmospheric chemistry-transport model CHIMERE. The maps were tested by comparing the CHIMERE simulations with time series of N2O concentrations measured at various heights above the ground in two locations in 2007. The emissions of N2O, as integrated over the region, were used in a life-cycle assessment of representative biofuel pathways: bioethanol from wheat and sugar-beet (1st generation), and miscanthus (2nd generation chain); bio-diesel from oilseed rape. Effects related to direct and indirect land-use changes (in particular on soil carbon stocks) were also included in the assessment based on various land-use scenarios and literature references. The potential deployment of miscanthus was simulated by assuming it would be grown on the current sugar-beet growing area in Ile-de-France, or by converting land currently under permanent fallow
Validation of gyrokinetic modelling of light impurity transport including rotation in ASDEX Upgrade
Casson, F J; Angioni, C; Camenen, Y; Dux, R; Fable, E; Fischer, R; Geiger, B; Manas, P; Menchero, L; Tardini, G
2013-01-01
Upgraded spectroscopic hardware and an improved impurity concentration calculation allow accurate determination of boron density in the ASDEX Upgrade tokamak. A database of boron measurements is compared to quasilinear and nonlinear gyrokinetic simulations including Coriolis and centrifugal rotational effects over a range of H-mode plasma regimes. The peaking of the measured boron profiles shows a strong anti-correlation with the plasma rotation gradient, via a relationship explained and reproduced by the theory. It is demonstrated that the rotodiffusive impurity flux driven by the rotation gradient is required for the modelling to reproduce the hollow boron profiles at higher rotation gradients. The nonlinear simulations validate the quasilinear approach, and, with the addition of perpendicular flow shear, demonstrate that each symmetry breaking mechanism that causes momentum transport also couples to rotodiffusion. At lower rotation gradients, the parallel compressive convection is required to match the mos...
Benedetti, Fabrizio; Dorier, Julien; Burnier, Yannis; Stasiak, Andrzej
2014-03-01
Understanding the structure of interphase chromosomes is essential to elucidate regulatory mechanisms of gene expression. During recent years, high-throughput DNA sequencing expanded the power of chromosome conformation capture (3C) methods that provide information about reciprocal spatial proximity of chromosomal loci. Since 2012, it is known that entire chromatin in interphase chromosomes is organized into regions with strongly increased frequency of internal contacts. These regions, with the average size of ∼1 Mb, were named topological domains. More recent studies demonstrated presence of unconstrained supercoiling in interphase chromosomes. Using Brownian dynamics simulations, we show here that by including supercoiling into models of topological domains one can reproduce and thus provide possible explanations of several experimentally observed characteristics of interphase chromosomes, such as their complex contact maps.
Sharma, Reena; Raghuwanshi, Sanjeev Kumar
2017-02-01
Line surveillance and management information in erbium-doped fiber amplifiers (EDFAs) can be broadcast by modulating the amplitude of the low-frequency lightwave information signal, the process termed as overmodulation in the literature. This paper presents systematic solutions for the overmodulated pump and information signal transfer functions for EDFA. It includes amplified spontaneous emission (ASE) that has an impact on outcomes in the high-gain system. To the extent of our belief, the methodical model simulated with the current approach leads to a distinct perspective of an outcome in the respective field. The test bed described here is realistic. It specifically represents the overmodulation behavior in an EDFA under the influence of ASE.
Tyner, Bryan C.; Fienup, Daniel M.
2015-01-01
Graphing is socially significant for behavior analysts; however, graphing can be difficult to learn. Video modeling (VM) may be a useful instructional method but lacks evidence for effective teaching of computer skills. A between-groups design compared the effects of VM, text-based instruction, and no instruction on graphing performance.…
This is the first of a series of 8 papers examining susceptibility of various rodent cardiometabolic disease models to ozone induced health effects. Individuals with cardiovascular and metabolic diseases (CVD) are shown to be more susceptible to adverse health effects o...
Energy Technology Data Exchange (ETDEWEB)
Chen, Lingen; Kan, Xuxian; Sun, Fengrui; Wu, Feng [College of Naval Architecture and Power, Naval University of Engineering, Wuhan 430033 (China)
2013-07-01
The operation of a universal steady flow endoreversible refrigeration cycle model consisting of a constant thermal-capacity heating branch, two constant thermal-capacity cooling branches and two adiabatic branches is viewed as a production process with exergy as its output. The finite time exergoeconomic performance optimization of the refrigeration cycle is investigated by taking profit rate optimization criterion as the objective. The relations between the profit rate and the temperature ratio of working fluid, between the COP (coefficient of performance) and the temperature ratio of working fluid, as well as the optimal relation between profit rate and the COP of the cycle are derived. The focus of this paper is to search the compromised optimization between economics (profit rate) and the utilization factor (COP) for endoreversible refrigeration cycles, by searching the optimum COP at maximum profit, which is termed as the finite-time exergoeconomic performance bound. Moreover, performance analysis and optimization of the model are carried out in order to investigate the effect of cycle process on the performance of the cycles using numerical example. The results obtained herein include the performance characteristics of endoreversible Carnot, Diesel, Otto, Atkinson, Dual and Brayton refrigeration cycles.
Directory of Open Access Journals (Sweden)
Lingen Chen, Xuxian Kan, Fengrui Sun, Feng Wu
2013-01-01
Full Text Available The operation of a universal steady flow endoreversible refrigeration cycle model consisting of a constant thermal-capacity heating branch, two constant thermal-capacity cooling branches and two adiabatic branches is viewed as a production process with exergy as its output. The finite time exergoeconomic performance optimization of the refrigeration cycle is investigated by taking profit rate optimization criterion as the objective. The relations between the profit rate and the temperature ratio of working fluid, between the COP (coefficient of performance and the temperature ratio of working fluid, as well as the optimal relation between profit rate and the COP of the cycle are derived. The focus of this paper is to search the compromised optimization between economics (profit rate and the utilization factor (COP for endoreversible refrigeration cycles, by searching the optimum COP at maximum profit, which is termed as the finite-time exergoeconomic performance bound. Moreover, performance analysis and optimization of the model are carried out in order to investigate the effect of cycle process on the performance of the cycles using numerical example. The results obtained herein include the performance characteristics of endoreversible Carnot, Diesel, Otto, Atkinson, Dual and Brayton refrigeration cycles.
Challenges of including nitrogen effects on decomposition in earth system models
Hobbie, S. E.
2011-12-01
Despite the importance of litter decomposition for ecosystem fertility and carbon balance, key uncertainties remain about how this fundamental process is affected by nitrogen (N) availability. Nevertheless, resolving such uncertainties is critical for mechanistic inclusion of such processes in earth system models, towards predicting the ecosystem consequences of increased anthropogenic reactive N. Towards that end, we have conducted a series of experiments examining nitrogen effects on litter decomposition. We found that both substrate N and externally supplied N (regardless of form) accelerated the initial decomposition rate. Faster initial decomposition rates were linked to the higher activity of carbohydrate-degrading enzymes associated with externally supplied N and the greater relative abundances of Gram negative and Gram positive bacteria associated with green leaves and externally supplied organic N (assessed using phospholipid fatty acid analysis, PLFA). By contrast, later in decomposition, externally supplied N slowed decomposition, increasing the fraction of slowly decomposing litter and reducing lignin-degrading enzyme activity and relative abundances of Gram negative and Gram positive bacteria. Our results suggest that elevated atmospheric N deposition may have contrasting effects on the dynamics of different soil carbon pools, decreasing mean residence times of active fractions comprising very fresh litter, while increasing those of more slowly decomposing fractions including more processed litter. Incorporating these contrasting effects of N on decomposition processes into models is complicated by lingering uncertainties about how these effects generalize across ecosystems and substrates.
A Model for One-Dimensional Coherent Synchrotron Radiation including Short-Range Effects
Ryne, Robert D; Qiang, Ji; Yampolsky, Nikolai
2012-01-01
A new model is presented for simulating coherent synchrotron radiation (CSR) in one dimension. The method is based on convolving an integrated Green function (IGF) with the longitudinal charge density. Since it is based on an IGF, the accuracy of this approach is determined by how well one resolves the charge density and not by resolving the single particle wake function. Since short-range wakefield effects are included analytically, the approach can be much more efficient than ordinary (non-IGF) approaches in situations where the wake function and charge density have disparate spatial scales. Two cases are presented: one derived from the full wake including short-range effects, and one derived from the asymptotic wake. In the latter case the algorithm contains the same physics as others based on the asymptotic approximation, but requires only the line charge density and not its derivative. Examples are presented that illustrate the limitations of the asymptotic-wake approximation, and that illustrate how mic...
INTERIOR MODELS OF SATURN: INCLUDING THE UNCERTAINTIES IN SHAPE AND ROTATION
Energy Technology Data Exchange (ETDEWEB)
Helled, Ravit [Department of Geophysics, Atmospheric and Planetary Sciences, Tel-Aviv University, Tel-Aviv (Israel); Guillot, Tristan [Universite de Nice-Sophia Antipolis, Observatoire de la Cote d' Azur, CNRS UMR 7293, BP 4229, F-06304 Nice (France)
2013-04-20
The accurate determination of Saturn's gravitational coefficients by Cassini could provide tighter constraints on Saturn's internal structure. Also, occultation measurements provide important information on the planetary shape which is often not considered in structure models. In this paper we explore how wind velocities and internal rotation affect the planetary shape and the constraints on Saturn's interior. We show that within the geodetic approach the derived physical shape is insensitive to the assumed deep rotation. Saturn's re-derived equatorial and polar radii at 100 mbar are found to be 54,445 {+-} 10 km and 60,365 {+-} 10 km, respectively. To determine Saturn's interior, we use one-dimensional three-layer hydrostatic structure models and present two approaches to include the constraints on the shape. These approaches, however, result in only small differences in Saturn's derived composition. The uncertainty in Saturn's rotation period is more significant: with Voyager's 10{sup h}39{sup m} period, the derived mass of heavy elements in the envelope is 0-7 M{sub Circled-Plus }. With a rotation period of 10{sup h}32{sup m}, this value becomes <4 M{sub Circled-Plus }, below the minimum mass inferred from spectroscopic measurements. Saturn's core mass is found to depend strongly on the pressure at which helium phase separation occurs, and is estimated to be 5-20 M{sub Circled-Plus }. Lower core masses are possible if the separation occurs deeper than 4 Mbar. We suggest that the analysis of Cassini's radio occultation measurements is crucial to test shape models and could lead to constraints on Saturn's rotation profile and departures from hydrostatic equilibrium.
Stucki, S; Orozco-terWengel, P; Forester, B R; Duruz, S; Colli, L; Masembe, C; Negrini, R; Landguth, E; Jones, M R; Bruford, M W; Taberlet, P; Joost, S
2016-11-01
With the increasing availability of both molecular and topo-climatic data, the main challenges facing landscape genomics - that is the combination of landscape ecology with population genomics - include processing large numbers of models and distinguishing between selection and demographic processes (e.g. population structure). Several methods address the latter, either by estimating a null model of population history or by simultaneously inferring environmental and demographic effects. Here we present samβada, an approach designed to study signatures of local adaptation, with special emphasis on high performance computing of large-scale genetic and environmental data sets. samβada identifies candidate loci using genotype-environment associations while also incorporating multivariate analyses to assess the effect of many environmental predictor variables. This enables the inclusion of explanatory variables representing population structure into the models to lower the occurrences of spurious genotype-environment associations. In addition, samβada calculates local indicators of spatial association for candidate loci to provide information on whether similar genotypes tend to cluster in space, which constitutes a useful indication of the possible kinship between individuals. To test the usefulness of this approach, we carried out a simulation study and analysed a data set from Ugandan cattle to detect signatures of local adaptation with samβada, bayenv, lfmm and an FST outlier method (FDIST approach in arlequin) and compare their results. samβada - an open source software for Windows, Linux and Mac OS X available at http://lasig.epfl.ch/sambada - outperforms other approaches and better suits whole-genome sequence data processing.
Scifoni, E.; Tinganelli, W.; Weyrather, W. K.; Durante, M.; Maier, A.; Krämer, M.
2013-06-01
We present a method for adapting a biologically optimized treatment planning for particle beams to a spatially inhomogeneous tumor sensitivity due to hypoxia, and detected e.g., by PET functional imaging. The TRiP98 code, established treatment planning system for particles, has been extended for including explicitly the oxygen enhancement ratio (OER) in the biological effect calculation, providing the first set up of a dedicated ion beam treatment planning approach directed to hypoxic tumors, TRiP-OER, here reported together with experimental tests. A simple semi-empirical model for calculating the OER as a function of oxygen concentration and dose averaged linear energy transfer, generating input tables for the program is introduced. The code is then extended in order to import such tables coming from the present or alternative models, accordingly and to perform forward and inverse planning, i.e., predicting the survival response of differently oxygenated areas as well as optimizing the required dose for restoring a uniform survival effect in the whole irradiated target. The multiple field optimization results show how the program selects the best beam components for treating the hypoxic regions. The calculations performed for different ions, provide indications for the possible clinical advantages of a multi-ion treatment. Finally the predictivity of the code is tested through dedicated cell culture experiments on extended targets irradiation using specially designed hypoxic chambers, providing a qualitative agreement, despite some limits in full survival calculations arising from the RBE assessment. The comparison of the predictions resulting by using different model tables are also reported.
Directory of Open Access Journals (Sweden)
Minghao eDong
2015-03-01
Full Text Available It is well established that expertise modulates evoked brain activity in response to specific stimuli. Recently, researchers have begun to investigate how expertise influences the resting brain. Among these studies, most focused on the connectivity features within/across regions, i.e. connectivity patterns/strength. However, little concern has been given to a more fundamental issue whether or not expertise modulates baseline brain activity. We investigated this question using amplitude of low-frequency (<0.08Hz fluctuation (ALFF as the metric of brain activity and a novel expertise model, i.e. acupuncturists, due to their robust proficiency in tactile perception and emotion regulation. After the psychophysical and behavioral expertise screening procedure, 23 acupuncturists and 23 matched non-acupuncturists (NA were enrolled. Our results explicated higher ALFF for acupuncturists in the left ventral medial prefrontal cortex (VMPFC and the contralateral hand representation of the primary somatosensory area (SI (corrected for multiple comparisons. Additionally, ALFF of VMPFC was negatively correlated with the outcomes of the emotion regulation task (corrected for multiple comparisons. We suggest that our study may reveal a novel connection between the neuroplasticity mechanism and resting state activity, which would upgrade our understanding of the central mechanism of learning. Furthermore, by showing that expertise can affect the baseline brain activity as indicated by ALFF, our findings may have profound implication for functional neuroimaging studies especially those involving expert models, in that difference in baseline brain activity may either smear the spatial pattern of activations for task data or introduce biased results into connectivity-based analysis for resting data.
Learning to Baseline Business Technology
Directory of Open Access Journals (Sweden)
David Gore
2013-10-01
Full Text Available bills, sign multi-‐year contracts, and make purchasing decisions without having an overall technology plan. That plan includes a technology baseline to fully assess existing technology. A CIO's goal is to align IT with business goals. Businesses must know total cost of ownership and the return on investment for all technology purchases and monthly costs. A business must also be able to manage technology assets and best utilize resources across the business. Teaching students to baseline technology will enable them to track and manage costs, discover errors and waste, and consolidate and improve existing technology.
Tyner, Bryan C; Fienup, Daniel M
2015-09-01
Graphing is socially significant for behavior analysts; however, graphing can be difficult to learn. Video modeling (VM) may be a useful instructional method but lacks evidence for effective teaching of computer skills. A between-groups design compared the effects of VM, text-based instruction, and no instruction on graphing performance. Participants who used VM constructed graphs significantly faster and with fewer errors than those who used text-based instruction or no instruction. Implications for instruction are discussed.
Directory of Open Access Journals (Sweden)
Tatyana N Tarasenko
Full Text Available Ornithine transcarbamylase deficiency (OTCD, OMIM# 311250 is an inherited X-linked urea cycle disorder that is characterized by hyperammonemia and orotic aciduria. In this report, we describe a new animal model of OTCD caused by a spontaneous mutation in the mouse Otc gene (c.240T>A, p.K80N. This transversion in exon 3 of ornithine transcarbamylase leads to normal levels of mRNA with low levels of mature protein and is homologous to a mutation that has also been described in a single patient affected with late-onset OTCD. With higher residual enzyme activity, spf-J were found to have normal plasma ammonia and orotate. Baseline plasma amino acid profiles were consistent with mild OTCD: elevated glutamine, and lower citrulline and arginine. In contrast to WT, spf-J displayed baseline elevations in cerebral amino acids with depletion following immune challenge with polyinosinic:polycytidylic acid. Our results indicate that the mild spf-J mutation constitutes a new mouse model that is suitable for mechanistic studies of mild OTCD and the exploration of cerebral pathophysiology during acute decompensation that characterizes proximal urea cycle dysfunction in humans.
Tarasenko, Tatyana N; Rosas, Odrick R; Singh, Larry N; Kristaponis, Kara; Vernon, Hilary; McGuire, Peter J
2015-01-01
Ornithine transcarbamylase deficiency (OTCD, OMIM# 311250) is an inherited X-linked urea cycle disorder that is characterized by hyperammonemia and orotic aciduria. In this report, we describe a new animal model of OTCD caused by a spontaneous mutation in the mouse Otc gene (c.240T>A, p.K80N). This transversion in exon 3 of ornithine transcarbamylase leads to normal levels of mRNA with low levels of mature protein and is homologous to a mutation that has also been described in a single patient affected with late-onset OTCD. With higher residual enzyme activity, spf-J were found to have normal plasma ammonia and orotate. Baseline plasma amino acid profiles were consistent with mild OTCD: elevated glutamine, and lower citrulline and arginine. In contrast to WT, spf-J displayed baseline elevations in cerebral amino acids with depletion following immune challenge with polyinosinic:polycytidylic acid. Our results indicate that the mild spf-J mutation constitutes a new mouse model that is suitable for mechanistic studies of mild OTCD and the exploration of cerebral pathophysiology during acute decompensation that characterizes proximal urea cycle dysfunction in humans.
DEFF Research Database (Denmark)
Bak, J.
2001-01-01
are subtracted one by one from the contaminated spectrum, and the length of the spectral contour within specified wavenumbers is then calculated. When the length of the contour is at a minimum, a condition is reached where the pure component part of the measured spectrum is absent and only the background signal......-factor PCR models based on pure gaseous 1 and 4 cm(-1) CO Fourier transform infrared (FT-IR) spectra (50-400 ppm) measured at ambient temperatures. The program is validated with measured CO spectra containing interferents such as N2O, CO2, and added Hitran-simulated H2O, CO2, and COS spectra, representing...
Kuscahyadi, Febriana; Meilano, Irwan; Riqqi, Akhmad
2017-07-01
Special Region of Yogyakarta Province (DIY) is one of Indonesian regions that often harmed by varied natural disasters which caused huge negative impacts. The most catastrophic one is earthquake in May, 27th 2006 with 6.3 magnitude moment [1], evoked 5716 people died, and economic losses for Rp. 29.1 Trillion, [2]. Their impacts could be minimized by committing disaster risk reduction program. Therefore, it is necessary to measure the natural disaster resilience within a region. Since infrastructure are might be able as facilities that means for evacuations, distribute supplies, and post disaster recovery [3], this research concerns to establish spatial modelling of natural disaster resilience using infrastructure components based on BRIC in DIY Province. There are three infrastructure used in this model; they are school, health facilities, and roads. Distance analysis is used to determine the level of resilient zone. The result gives the spatial understanding as a map that urban areas have better disaster resilience than the rural areas. The coastal areas and mountains areas which are vulnerable towards disaster have less resilience since there are no enough facilities that will increase the disaster resilience
Directory of Open Access Journals (Sweden)
W. Kapturkiewicz
2008-12-01
Full Text Available The, developed in this study, simple model and numerical solution of diffusion growth of the solid phase under the conditions of directional solidification allow for the effect of constituent diffusion in both liquid and solid phase and assume the process run in which (like in reality the preset parameter is the velocity of sample (pulling velocity at a preset temperature gradient. The solid/liquid interface velocity is not the process parameter (like it is in numerous other solutions proposed so far but a function of this process. The effect of convection outside the diffusion layer has been included in mass balance under the assumption that in the zone of convection the mixing is complete. The above assumptions enabled solving the kinetics of growth of the solid phase (along with the diffusion field in solid and liquid phase under the conditions of diffusion well reflecting the process run starting with the initial transient state, going through the steady state period in central part of the casting, and ending in a terminal transient state. In the numerical solution obtained by the finite difference method with variable grid dimensions, the error of the mass control balance over the whole process range was 1 - 2 %.
Satpathy, Preseela; Biernacki, Piotr; Cypionka, Heribert; Steinigeweg, Sven
2016-12-05
A modified Anaerobic Digestion Model No. 1 (ADM1xp) including lactate was applied to a full-scale biogas plant. This model considers monosaccharides to degrade through lactic acid, which further degrades majorly into acetate followed by propionate and butyrate. Experimental data were derived from the previous works in the same laboratory, and the proposed parameters were validated against batch experiments. After successful validation, the biogas plant bearing a fermenter size of 7 dam(3) and operated with food waste and cattle manure was simulated. The biogas production and methane content were reliably simulated, and a good fit could be obtained against the experimental data with an average difference of less than 1%. When compared to the original ADM1 model, the performance of the lactate-incorporated model was found to be improved. Inclusion of lactate as a parameter in the ADM1xp model is recommended for an increased sensitivity and enhanced prediction principally for systems dealing with high carbohydrate and lactate loads.
Indian Academy of Sciences (India)
Wei Lu; Qingchun Yang; Jordi D Martín; Ricardo Juncosa
2013-04-01
During the 1990s, groundwater overexploitation has resulted in seawater intrusion in the coastal aquifer of the Shenzhen city, China. Although water supply facilities have been improved and alleviated seawater intrusion in recent years, groundwater overexploitation is still of great concern in some local areas. In this work we present a three-dimensional density-dependent numerical model developed with the FEFLOW code, which is aimed at simulating the extent of seawater intrusion while including tidal effects and different groundwater pumping scenarios. Model calibration, using waterheads and reported chloride concentration, has been performed based on the data from 14 boreholes, which were monitored from May 2008 to December 2009. A fairly good fitness between the observed and computed values was obtained by a manual trial-and-error method. Model prediction has been carried out forward 3 years with the calibrated model taking into account high, medium and low tide levels and different groundwater exploitation schemes. The model results show that tide-induced seawater intrusion significantly affects the groundwater levels and concentrations near the estuarine of the Dasha river, which implies that an important hydraulic connection exists between this river and groundwater, even considering that some anti-seepage measures were taken in the river bed. Two pumping scenarios were considered in the calibrated model in order to predict the future changes in the water levels and chloride concentration. The numerical results reveal a decreased tendency of seawater intrusion if groundwater exploitation does not reach an upper bound of about 1.32 × 104 m3/d. The model results provide also insights for controlling seawater intrusion in such coastal aquifer systems.
ETM documentation update – including modelling conventions and manual for software tools
DEFF Research Database (Denmark)
Grohnheit, Poul Erik
, it summarises the work done during 2013, and it also contains presentations for promotion of fusion as a future element in the electricity generation mix and presentations for the modelling community concerning model development and model documentation – in particular for TIAM collaboration workshops....
Latham, J.P.; Xiang, J.; Belayneh, M.; Nick, H.M.; Tsang, C.F.; Blunt, M.J.
2013-01-01
The influence of in-situ stresses on flow processes in fractured rock is investigated using a novel modelling approach. The combined finite-discrete element method (FEMDEM) is used to model the deformation of a fractured rock mass. The fracture wall displacements and aperture changes are modelled in
A sub-circuit MOSFET model with a wide temperature range including cryogenic temperature*
Institute of Scientific and Technical Information of China (English)
Jia Kan; Sun Weifeng; Shi Longxing
2011-01-01
A sub-circuit SPICE model ofa MOSFET for low temperature operation is presented. Two resistors are introduced for the freeze-out effect, and the explicit behavioral models are developed for them. The model can be used in a wide temperature range covering both cryogenic temperature and regular temperatures.
Including Overweight or Obese Students in Physical Education: A Social Ecological Constraint Model
Li, Weidong; Rukavina, Paul
2012-01-01
In this review, we propose a social ecological constraint model to study inclusion of overweight or obese students in physical education by integrating key concepts and assumptions from ecological constraint theory in motor development and social ecological models in health promotion and behavior. The social ecological constraint model proposes…
Parrish, D. D.; Lamarque, J.-F.; Naik, V.; Horowitz, L.; Shindell, D. T.; Staehelin, J.; Derwent, R.; Cooper, O. R.; Tanimoto, H.; Volz-Thomas, A.;
2014-01-01
Two recent papers have quantified long-term ozone (O3) changes observed at northernmidlatitude sites that are believed to represent baseline (here understood as representative of continental to hemispheric scales) conditions. Three chemistry-climate models (NCAR CAM-chem, GFDL-CM3, and GISS-E2-R) have calculated retrospective tropospheric O3 concentrations as part of the Atmospheric Chemistry and Climate Model Intercomparison Project and Coupled Model Intercomparison Project Phase 5 model intercomparisons. We present an approach for quantitative comparisons of model results with measurements for seasonally averaged O3 concentrations. There is considerable qualitative agreement between the measurements and the models, but there are also substantial and consistent quantitative disagreements. Most notably, models (1) overestimate absolute O3 mixing ratios, on average by approximately 5 to 17 ppbv in the year 2000, (2) capture only approximately 50% of O3 changes observed over the past five to six decades, and little of observed seasonal differences, and (3) capture approximately 25 to 45% of the rate of change of the long-term changes. These disagreements are significant enough to indicate that only limited confidence can be placed on estimates of present-day radiative forcing of tropospheric O3 derived from modeled historic concentration changes and on predicted future O3 concentrations. Evidently our understanding of tropospheric O3, or the incorporation of chemistry and transport processes into current chemical climate models, is incomplete. Modeled O3 trends approximately parallel estimated trends in anthropogenic emissions of NO(sub x), an important O3 precursor, while measured O3 changes increase more rapidly than these emission estimates.
A methodology for including wall roughness effects in k-ε low-Reynolds turbulence models
Energy Technology Data Exchange (ETDEWEB)
Ambrosini, W., E-mail: walter.ambrosini@ing.unipi.it; Pucciarelli, A.; Borroni, I.
2015-05-15
Highlights: • A model for taking into account wall roughness in low-Reynolds k-ε models is presented. • The model is subjected to a first validation to show its potential in general applications. • The application of the model in predicting heat transfer to supercritical fluids is also discussed. - Abstract: A model accounting for wall roughness effects in k-ε low-Reynolds turbulence models is described in the present paper. In particular, the introduction in the transport equations of k and ε of additional source terms related to roughness, based on simple assumptions and dimensional relationships, is proposed. An objective of the present paper, in addition to obtaining more realistic predictions of wall friction, is the application of the proposed model to the study of heat transfer to supercritical fluids. A first validation of the model is reported. The model shows the capability of predicting, at least qualitatively, some of the most important trends observed when dealing with rough pipes in very different flow conditions. Qualitative comparisons with some DNS data available in literature are also performed. Further analyses provided promising results concerning the ability of the model in reproducing the trend of friction factor when varying the flow conditions, though improvements are necessary for achieving better quantitative accuracy. First applications of the model in simulating heat transfer to supercritical fluids are also described, showing the capability of the model to affect the predictions of these heat transfer phenomena, in particular in the vicinity of the pseudo-critical conditions. A more extended application of the model to relevant deteriorated heat transfer conditions will clarify the usefulness of this modelling methodology in improving predictions of these difficult phenomena. Whatever the possible success in this particular application that motivated its development, this approach suggests a general methodology for accounting
Parra, J.; Vicuña, Cristián Molina
2017-08-01
Planetary gearboxes are important components of many industrial applications. Vibration analysis can increase their lifetime and prevent expensive repair and safety concerns. However, an effective analysis is only possible if the vibration features of planetary gearboxes are properly understood. In this paper, models are used to study the frequency content of planetary gearbox vibrations under non-fault and different fault conditions. Two different models are considered: phenomenological model, which is an analytical-mathematical formulation based on observation, and lumped-parameter model, which is based on the solution of the equations of motion of the system. Results of both models are not directly comparable, because the phenomenological model provides the vibration on a fixed radial direction, such as the measurements of the vibration sensor mounted on the outer part of the ring gear. On the other hand, the lumped-parameter model provides the vibrations on the basis of a rotating reference frame fixed to the carrier. To overcome this situation, a function to decompose the lumped-parameter model solutions to a fixed reference frame is presented. Finally, comparisons of results from both model perspectives and experimental measurements are presented.
A two-dimensional simulation model of phosphorus uptake including crop growth and P-response
Mollier, A.; Willigen, de P.; Heinen, M.; Morel, C.; Schneider, A.; Pellerin, S.
2008-01-01
Modelling nutrient uptake by crops implies considering and integrating the processes controlling the soil nutrient supply, the uptake by the root system and relationships between the crop growth response and the amount of nutrient absorbed. We developed a model that integrates both dynamics of maize
European column buckling curves and finite element modelling including high strength steels
DEFF Research Database (Denmark)
Jönsson, Jeppe; Stan, Tudor-Cristian
2017-01-01
Eurocode allows for finite element modelling of plated steel structures, however the information in the code on how to perform the analysis or what assumptions to make is quite sparse. The present paper investigates the deterministic modelling of flexural column buckling using plane shell element...
Dipole model analysis of highest precision HERA data, including very low $Q^2$'s
Luszczak, Agnieszka
2016-01-01
We analyse, within a dipole model, the final, inclusive HERA DIS cross section data in the low $x$ region, using fully correlated errors. We show, that these highest precision data are very well described within the dipole model framework starting from $Q^2$ values of 3.5 GeV$^2$ to the highest values of $Q^2 =$ 250 GeV$^2$.
A Two-Account Life Insurance Model for Scenario-Based Valuation Including Event Risk
DEFF Research Database (Denmark)
Jensen, Ninna Reitzel; Schomacker, Kristian Juul
2015-01-01
Using a two-account model with event risk, we model life insurance contracts taking into account both guaranteed and non-guaranteed payments in participating life insurance as well as in unit-linked insurance. Here, event risk is used as a generic term for life insurance events, such as death......, disability, etc. In our treatment of participating life insurance, we have special focus on the bonus schemes “consolidation” and “additional benefits”, and one goal is to formalize how these work and interact. Another goal is to describe similarities and differences between participating life insurance...... model by conducting scenario analysis based on Monte Carlo simulation, but the model applies to scenarios in general and to worst-case and best-estimate scenarios in particular. In addition to easy computations, our model offers a common framework for the valuation of life insurance payments across...
A Two-Account Life Insurance Model for Scenario-Based Valuation Including Event Risk
DEFF Research Database (Denmark)
Jensen, Ninna Reitzel; Schomacker, Kristian Juul
2015-01-01
and unit-linked insurance. By use of a two-account model, we are able to illustrate general concepts without making the model too abstract. To allow for complicated financial markets without dramatically increasing the mathematical complexity, we focus on economic scenarios. We illustrate the use of our......Using a two-account model with event risk, we model life insurance contracts taking into account both guaranteed and non-guaranteed payments in participating life insurance as well as in unit-linked insurance. Here, event risk is used as a generic term for life insurance events, such as death...... product types. This enables comparison of participating life insurance products and unit-linked insurance products, thus building a bridge between the two different ways of formalizing life insurance products. Finally, our model distinguishes itself from the existing literature by taking into account...
Gasification of biomass in a fixed bed downdraft gasifier--a realistic model including tar.
Barman, Niladri Sekhar; Ghosh, Sudip; De, Sudipta
2012-03-01
This study presents a model for fixed bed downdraft biomass gasifiers considering tar also as one of the gasification products. A representative tar composition along with its mole fractions, as available in the literature was used as an input parameter within the model. The study used an equilibrium approach for the applicable gasification reactions and also considered possible deviations from equilibrium to further upgrade the equilibrium model to validate a range of reported experimental results. Heat balance was applied to predict the gasification temperature and the predicted values were compared with reported results in literature. A comparative study was made with some reference models available in the literature and also with experimental results reported in the literature. Finally a predicted variation of performance of the gasifier by this validated model for different air-fuel ratio and moisture content was also discussed.
Including Tropical Croplands in a Terrestrial Biosphere Model: Application to West Africa
Berg, A.; Sultan, B.; de Noblet, N.
2008-12-01
Studying the large-scale relationships between climate and agriculture raises two different issues: the impact of climate on crops, and the potential feedbacks to climate from croplands. A relevant framework to consistently address this twofold issue is to extend existing Dynamic Global Vegetation Models, which can be coupled to climate models, in order to explicitly account for croplands. Here we present the first results of such a strategy applied to tropical croplands over West Africa. We introduce directly into the terrestrial biosphere model ORCHIDEE (IPSL) adequate processes and parametrizations taken from the crop model SARRAH (CIRAD), which is calibrated for millet over this region. The resulting model, ORCH-mil, realistically simulates the growth and yield of millet when tested on an experimental station in Senegal. The model is then applied over West Africa using a 36-year climate reanalysis dataset. First the model is tested in terms of yield simulation, against national millet yields from the FAO database. The ability of the model to reproduce the spatial and temporal variability of millet yields is assessed. Then, the effects on land surface fluxes of explicitly accounting for croplands are examined, by comparison between ORCH-mil and ORCHIDEE. These first simulations show consistent results, but underline the need for some further development and validation of the model if it is to simulate yields accurately. In terms of land surface fluxes, significant differences between ORCH-mil and ORCHIDEE appear, mainly via changes in evaporation and albedo. The potential impact on the west African monsoon system of such differences needs to be investigated by coupling ORCH-mil to a climate model: first results from such an experiment will be presented.
Energy Technology Data Exchange (ETDEWEB)
Carlen, Ida; Nikolopoulos, Anna; Isaeus, Martin (AquaBiota Water Research, Stockholm (SE))
2007-06-15
GIS grids (maps) of marine parameters were created using point data from previous site investigations in the Forsmark and Oskarshamn areas. The proportion of global radiation reaching the sea bottom in Forsmark and Oskarshamn was calculated in ArcView, using Secchi depth measurements and the digital elevation models for the respective area. The number of days per year when the incoming light exceeds 5 MJ/m2 at the bottom was then calculated using the result of the previous calculations together with measured global radiation. Existing modelled grid-point data on bottom and pelagic temperature for Forsmark were interpolated to create surface covering grids. Bottom and pelagic temperature grids for Oskarshamn were calculated using point measurements to achieve yearly averages for a few points and then using regressions with existing grids to create new maps. Phytoplankton primary production in Forsmark was calculated using point measurements of chlorophyll and irradiance, and a regression with a modelled grid of Secchi depth. Distribution of biomass of macrophyte communities in Forsmark and Oskarshamn was calculated using spatial modelling in GRASP, based on field data from previous surveys. Physical parameters such as those described above were used as predictor variables. Distribution of biomass of different functional groups of fish in Forsmark was calculated using spatial modelling based on previous surveys and with predictor variables such as physical parameters and results from macrophyte modelling. All results are presented as maps in the report. The quality of the modelled predictions varies as a consequence of the quality and amount of the input data, the ecology and knowledge of the predicted phenomena, and by the modelling technique used. A substantial part of the variation is not described by the models, which should be expected for biological modelling. Therefore, the resulting grids should be used with caution and with this uncertainty kept in mind. All
Neumann, R. B.; Cardon, Z. G.; Rockwell, F. E.; Teshera-Levye, J.; Zwieniecki, M.; Holbrook, N. M.
2013-12-01
The movement of water from moist to dry soil layers through the root systems of plants, referred to as hydraulic redistribution (HR), occurs throughout the world and is thought to influence carbon and water budgets and ecosystem functioning. The realized hydrologic, biogeochemical, and ecological consequences of HR depend on the amount of redistributed water, while the ability to assess these impacts requires models that correctly capture HR magnitude and timing. Using several soil types and two eco-types of Helianthus annuus L. in split-pot experiments, we examined how well the widely used HR modeling formulation developed by Ryel et al. (2002) could match experimental determination of HR across a range of water potential driving gradients. H. annuus carries out extensive nighttime transpiration, and though over the last decade it has become more widely recognized that nighttime transpiration occurs in multiple species and many ecosystems, the original Ryel et al. (2002) formulation does not include the effect of nighttime transpiration on HR. We developed and added a representation of nighttime transpiration into the formulation, and only then was the model able to capture the dynamics and magnitude of HR we observed as soils dried and nighttime stomatal behavior changed, both influencing HR.
Constraints on gen4eralized Chaplygin gas model including gamma-ray bursts
Institute of Scientific and Technical Information of China (English)
Fa-Yin Wang; Zi-Gao Dai; Shi Qi
2009-01-01
Generalized Chaplygin gas (whose equation of state is PGCG = -A/PGCGα) was proposed as a candidate for unification of dark energy and dark matter. We inves-tigate constraints on this model with the latest observed data. We test the model with type-Ia supernovae (SNe Ia), cosmic microwave background (CMB) anisotropy, X-ray gas mass fractions in clusters, and gamma-ray bursts (GRBs). We calibrate the GRB lu-minosity relations without assuming any cosmological models using SNe Ia. We show that GRBs can extend the Hubble diagram to higher redshifts (z> 6). The GRB Hubble diagram is well behaved and delineates the shape of the Hubble diagram well. We mea-sure As≡A/PGCG,0α+1=0.68-0.08+0.04 (where PGCG,0 is the energy density today) and α=-0.22-0.13+0.15at the 1σconfidence level using all the datasets. Our results rule out the standard Chaplygin gas model (α = 1) at the 3a confidence level. The ACDM is allowed at the 2or confidence level. We find that acceleration could have started at a redshift of z ～ 0.70. The concordance of the generalized Chaplygin gas model with the age estimate of an old high redshift quasar is found. In addition, we show that GRBs can break the degeneracy between the generalized Chaplygin gas model and the XCDM model.
Simulated village locations in Thailand: A multi-scale model including a neural network approach.
Tang, Wenwu; Malanson, George P; Entwisle, Barbara
2009-04-01
The simulation of rural land use systems, in general, and rural settlement dynamics in particular has developed with synergies of theory and methods for decades. Three current issues are: linking spatial patterns and processes, representing hierarchical relations across scales, and considering nonlinearity to address complex non-stationary settlement dynamics. We present a hierarchical simulation model to investigate complex rural settlement dynamics in Nang Rong, Thailand. This simulation uses sub-models to allocate new villages at three spatial scales. Regional and sub-regional models, which involve a nonlinear space-time autoregressive model implemented in a neural network approach, determine the number of new villages to be established. A dynamic village niche model, establishing pattern-process link, was designed to enable the allocation of villages into specific locations. Spatiotemporal variability in model performance indicates the pattern of village location changes as a settlement frontier advances from rice-growing lowlands to higher elevations. Experiments results demonstrate this simulation model can enhance our understanding of settlement development in Nang Rong and thus gain insight into complex land use systems in this area.
A Two-Account Life Insurance Model for Scenario-Based Valuation Including Event Risk
Directory of Open Access Journals (Sweden)
Ninna Reitzel Jensen
2015-06-01
Full Text Available Using a two-account model with event risk, we model life insurance contracts taking into account both guaranteed and non-guaranteed payments in participating life insurance as well as in unit-linked insurance. Here, event risk is used as a generic term for life insurance events, such as death, disability, etc. In our treatment of participating life insurance, we have special focus on the bonus schemes “consolidation” and “additional benefits”, and one goal is to formalize how these work and interact. Another goal is to describe similarities and differences between participating life insurance and unit-linked insurance. By use of a two-account model, we are able to illustrate general concepts without making the model too abstract. To allow for complicated financial markets without dramatically increasing the mathematical complexity, we focus on economic scenarios. We illustrate the use of our model by conducting scenario analysis based on Monte Carlo simulation, but the model applies to scenarios in general and to worst-case and best-estimate scenarios in particular. In addition to easy computations, our model offers a common framework for the valuation of life insurance payments across product types. This enables comparison of participating life insurance products and unit-linked insurance products, thus building a bridge between the two different ways of formalizing life insurance products. Finally, our model distinguishes itself from the existing literature by taking into account the Markov model for the state of the policyholder and, hereby, facilitating event risk.
Energy Technology Data Exchange (ETDEWEB)
Ozolin, Y.E.; Karol, I.L. [Main Geophysical Observatory, St. Petersburg (Russian Federation); Ramaroson, R. [Office National d`Etudes et de Recherches Aerospatiales (ONERA), 92 - Chatillon (France)
1997-12-31
Box model for coupled gaseous and aqueous phases is used for sensitivity study of potential transformation of trace gases in a cloud environment. The rate of this transformation decreases with decreasing of pH in droplets, with decreasing of photodissociation rates inside the cloud and with increasing of the droplet size. Model calculations show the potential formation of H{sub 2}O{sub 2} in aqueous phase and transformation of gaseous HNO{sub 3} into NO{sub x} in a cloud. This model is applied for exploration of aircraft exhausts evolution in plume inside a cloud. (author) 10 refs.
Directory of Open Access Journals (Sweden)
Rosa Ana Salas
2013-11-01
Full Text Available We propose a modeling procedure specifically designed for a ferrite inductor excited by a waveform in time domain. We estimate the loss resistance in the core (parameter of the electrical model of the inductor by means of a Finite Element Method in 2D which leads to significant computational advantages over the 3D model. The methodology is validated for an RM (rectangular modulus ferrite core working in the linear and the saturation regions. Excellent agreement is found between the experimental data and the computational results.
Recent Advances in Study on Thermodynamic Models for Real Systems Including Electrolytes
Institute of Scientific and Technical Information of China (English)
无
2006-01-01
A comprehensive review of recent advances in study on thermodynamic models for real electrolyte solutions is presented. The differences between primitive and non-primitive electrolyte models are demonstrated. Some new thermodynamic models for electrolyte solutions based on the mean spherical approximation and perturbation theory are introduced. An extended scaled-particle theory and modified CleggPitz er equation are presented for physical and chemical absorption processes with mixed solvents, respectively. A pseudo one-component two-Yukawa equation of state is used for the aqueous two-phase extraction process in charged colloidal systems.
Extension of Lithium Ion Cell Model to Include Transient and Low-Temperature Behaviour
Dudley, G.
2014-08-01
Current-interruption resistance measurements have been analysed in detail allowing the ESTEC lithium ion cell electrical/thermal model to be extended to allow modelling of cell voltage in response to imposed current changes at low temperatures and short time scales where activation polarisation becomes important. Whilst an unnecessary complication in most cases, this extension is needed under certain circumstances such as the simulation of Mars rover batteries forced to operate at low temperature and possible effects of battery voltage transients on battery-bus power subsystems. Comparison with test data show that the model is capable of giving a good fit in these circumstances.
Qiuyang, He; Yue, Xu; Feifei, Zhao
2013-10-01
An accurate and complete circuit simulation model for single-photon avalanche diodes (SPADs) is presented. The derived model is not only able to simulate the static DC and dynamic AC behaviors of an SPAD operating in Geiger-mode, but also can emulate the second breakdown and the forward bias behaviors. In particular, it considers important statistical effects, such as dark-counting and after-pulsing phenomena. The developed model is implemented using the Verilog-A description language and can be directly performed in commercial simulators such as Cadence Spectre. The Spectre simulation results give a very good agreement with the experimental results reported in the open literature. This model shows a high simulation accuracy and very fast simulation rate.
Extending the Scope of the Acculturation/Pidginization Model to Include Cognition.
Schumann, John H.
1990-01-01
Examines five cognitive models for second-language acquisition (SLA) and assesses how each might account for the Pidginized interlanguage found in the early stages of second-language acquisition. (23 references) (JL)
A model for including Arduino microcontroller programming in the introductory physics lab
Haugen, Andrew J
2014-01-01
The paper describes a curricular framework for introducing microcontroller programming in the University Physics lab. The approach makes use of Modeling Instruction, an effective approach for teaching science at the secondary level in which student learn the standard material by developing and deploying models of the physical world. In our approach, students engage with a context-rich problem that can be solved with one or more sensors and a microcontroller. The solution path we describe then consists of developing a mathematical model for how the sensors' data can be mapped to a meaningful measurement, and further, developing an algorithmic model that will be implemented in the microcontroller. Once the system is developed and implemented, students are given an array of similar problems in which they can deploy their data collection system. Results from the implementation of this idea, in two University Physics sections, using Arduino microcontrollers, are also described.
Global warming in a coupled climate model including oceanic eddy-induced advection
Hirst, Anthony C.; Gordon, Hal B.; O'Farrell, Siobhan P.
The Gent and McWilliams (GM) parameterization for large-scale water transport caused by mesoscale oceanic eddies is introduced into the oceanic component of a global coupled ocean-atmosphere model. Parallel simulations with and without the GM scheme are performed to examine the effect of this parameterization on model behavior under constant atmospheric CO2 and on the model response to increasing CO2. The control (constant CO2) runs show substantial differences in the oceanic stratification and extent of convection, similar to differences found previously using uncoupled ocean models. The transient (increasing CO2) runs show moderate differences in the rate of oceanic heat sequestration (less in the GM case), as expected based on passive tracer uptake studies. However, the surface warming is weaker in the GM case, especially over the Southern Ocean, which is contrary to some recent supposition. Reasons for the reduced warming in the GM case are discussed.
Empirical Validation of a Thermal Model of a Complex Roof Including Phase Change Materials
Guichard, Stéphane; Bigot, Dimitri; Malet-Damour, Bruno; Libelle, Teddy; Boyer, Harry
2015-01-01
This paper deals with the empirical validation of a building thermal model using a phase change material (PCM) in a complex roof. A mathematical model dedicated to phase change materials based on the heat apparent capacity method was implemented in a multi-zone building simulation code, the aim being to increase understanding of the thermal behavior of the whole building with PCM technologies. To empirically validate the model, the methodology is based both on numerical and experimental studies. A parametric sensitivity analysis was performed and a set of parameters of the thermal model have been identified for optimization. The use of a generic optimization program called GenOpt coupled to the building simulation code enabled to determine the set of adequate parameters. We first present the empirical validation methodology and main results of previous work. We then give an overview of GenOpt and its coupling with the building simulation code. Finally, once the optimization results are obtained, comparisons o...
Kawasaki, Akira; Kubota, Kenichi; Funaki, Ikkoh; Okuno, Yoshihiro
2016-09-01
Steady-state and self-field magnetoplasmadynamic (MPD) thruster, which utilizes high-intensity direct-current (DC) discharge, is one of the prospective candidates of future high-power electric propulsion devices. In order to accurately assess the thrust performance and the electrode temperature, input electric power and wall heat flux must correctly be evaluated where electrostatic sheaths formed in close proximity of the electrodes affect these quantities. Conventional model simulates only plasma flows occurring in MPD thrusters with the absence of electrostatic sheath consideration. Therefore, this study extends the conventional model to a coupled magnetohydrodynamic (MHD) and thermal model by incorporating the phenomena relevant to the electrostatic sheaths. The sheaths are implemented as boundary condition of the MHD model on the walls. This model simulated the operation of the 100-kW-class thruster at discharge current ranging from 6 to 10 kA with argon propellant. The extended model reproduced the discharge voltages and wall heat load which are consistent with past experimental results. In addition, the simulation results indicated that cathode sheath voltages account for approximately 5-7 V subject to approximately 20 V of discharge voltages applied between the electrodes. This work was supported by JSPS KAKENHI Grant Numbers 26289328 and 15J10821.
Including sugar cane in the agro-ecosystem model ORCHIDEE-STICS: calibration and validation
Valade, A.; Vuichard, N.; Ciais, P.; Viovy, N.
2011-12-01
Sugarcane is currently the most efficient bioenergy crop with regards to the energy produced per hectare. With approximately half the global bioethanol production in 2005, and a devoted land area expected to expand globally in the years to come, sugar cane is at the heart of the biofuel debate. Dynamic global vegetation models coupled with agronomical models are powerful and novel tools to tackle many of the environmental issues related to biofuels if they are carefully calibrated and validated against field observations. Here we adapt the agro-terrestrial model ORCHIDEE-STICS for sugar cane simulations. Observation data of LAI are used to evaluate the sensitivity of the model to parameters of nitrogen absorption and phenology, which are calibrated in a systematic way for six sites in Australia and La Reunion. We find that the optimal set of parameters is highly dependent on the sites' characteristics and that the model can reproduce satisfactorily the evolution of LAI. This careful calibration of ORCHIDEE-STICS for sugar cane biomass production for different locations and technical itineraries provides a strong basis for further analysis of the impacts of bioenergy-related land use change on carbon cycle budgets. As a next step, a sensitivity analysis is carried out to estimate the uncertainty of the model in biomass and carbon flux simulation due to its parameterization.
Canuto, V. M.
1994-01-01
The Reynolds numbers that characterize geophysical and astrophysical turbulence (Re approximately equals 10(exp 8) for the planetary boundary layer and Re approximately equals 10(exp 14) for the Sun's interior) are too large to allow a direct numerical simulation (DNS) of the fundamental Navier-Stokes and temperature equations. In fact, the spatial number of grid points N approximately Re(exp 9/4) exceeds the computational capability of today's supercomputers. Alternative treatments are the ensemble-time average approach, and/or the volume average approach. Since the first method (Reynolds stress approach) is largely analytical, the resulting turbulence equations entail manageable computational requirements and can thus be linked to a stellar evolutionary code or, in the geophysical case, to general circulation models. In the volume average approach, one carries out a large eddy simulation (LES) which resolves numerically the largest scales, while the unresolved scales must be treated theoretically with a subgrid scale model (SGS). Contrary to the ensemble average approach, the LES+SGS approach has considerable computational requirements. Even if this prevents (for the time being) a LES+SGS model to be linked to stellar or geophysical codes, it is still of the greatest relevance as an 'experimental tool' to be used, inter alia, to improve the parameterizations needed in the ensemble average approach. Such a methodology has been successfully adopted in studies of the convective planetary boundary layer. Experienc e with the LES+SGS approach from different fields has shown that its reliability depends on the healthiness of the SGS model for numerical stability as well as for physical completeness. At present, the most widely used SGS model, the Smagorinsky model, accounts for the effect of the shear induced by the large resolved scales on the unresolved scales but does not account for the effects of buoyancy, anisotropy, rotation, and stable stratification. The
Toyokuni, Genti; Takenaka, Hiroshi
2012-06-01
We propose a method for modeling global seismic wave propagation through an attenuative Earth model including the center. This method enables accurate and efficient computations since it is based on the 2.5-D approach, which solves wave equations only on a 2-D cross section of the whole Earth and can correctly model 3-D geometrical spreading. We extend a numerical scheme for the elastic waves in spherical coordinates using the finite-difference method (FDM), to solve the viscoelastodynamic equation. For computation of realistic seismic wave propagation, incorporation of anelastic attenuation is crucial. Since the nature of Earth material is both elastic solid and viscous fluid, we should solve stress-strain relations of viscoelastic material, including attenuative structures. These relations represent the stress as a convolution integral in time, which has had difficulty treating viscoelasticity in time-domain computation such as the FDM. However, we now have a method using so-called memory variables, invented in the 1980s, followed by improvements in Cartesian coordinates. Arbitrary values of the quality factor (Q) can be incorporated into the wave equation via an array of Zener bodies. We also introduce the multi-domain, an FD grid of several layers with different grid spacings, into our FDM scheme. This allows wider lateral grid spacings with depth, so as not to perturb the FD stability criterion around the Earth center. In addition, we propose a technique to avoid the singularity problem of the wave equation in spherical coordinates at the Earth center. We develop a scheme to calculate wavefield variables on this point, based on linear interpolation for the velocity-stress, staggered-grid FDM. This scheme is validated through a comparison of synthetic seismograms with those obtained by the Direct Solution Method for a spherically symmetric Earth model, showing excellent accuracy for our FDM scheme. As a numerical example, we apply the method to simulate seismic
A two-phase solid/fluid model for dense granular flows including dilatancy effects
Mangeney, Anne; Bouchut, Francois; Fernandez-Nieto, Enrique; Koné, El-Hadj; Narbona-Reina, Gladys
2016-04-01
Describing grain/fluid interaction in debris flows models is still an open and challenging issue with key impact on hazard assessment [{Iverson et al.}, 2010]. We present here a two-phase two-thin-layer model for fluidized debris flows that takes into account dilatancy effects. It describes the velocity of both the solid and the fluid phases, the compression/dilatation of the granular media and its interaction with the pore fluid pressure [{Bouchut et al.}, 2016]. The model is derived from a 3D two-phase model proposed by {Jackson} [2000] based on the 4 equations of mass and momentum conservation within the two phases. This system has 5 unknowns: the solid and fluid velocities, the solid and fluid pressures and the solid volume fraction. As a result, an additional equation inside the mixture is necessary to close the system. Surprisingly, this issue is inadequately accounted for in the models that have been developed on the basis of Jackson's work [{Bouchut et al.}, 2015]. In particular, {Pitman and Le} [2005] replaced this closure simply by imposing an extra boundary condition at the surface of the flow. When making a shallow expansion, this condition can be considered as a closure condition. However, the corresponding model cannot account for a dissipative energy balance. We propose here an approach to correctly deal with the thermodynamics of Jackson's model by closing the mixture equations by a weak compressibility relation following {Roux and Radjai} [1998]. This relation implies that the occurrence of dilation or contraction of the granular material in the model depends on whether the solid volume fraction is respectively higher or lower than a critical value. When dilation occurs, the fluid is sucked into the granular material, the pore pressure decreases and the friction force on the granular phase increases. On the contrary, in the case of contraction, the fluid is expelled from the mixture, the pore pressure increases and the friction force diminishes. To
Including the effects of debris cover in a distributed glacier energy balance model (Invited)
Pellicciotti, F.; Reid, T.; Carenzo, M.; Brock, B. W.
2010-12-01
Distributed models of glacier energy balance, which make use of digital elevation models and extensive spatial data on local meteorology, have become very useful tools for predicting glacial ablation and runoff in recent years. They generally function by running a one-dimensional energy balance model at every point on a grid on the glacier surface - for each point in the grid the ablation is calculated based on the balance of heat fluxes at the ice-air boundary. However, one key component has been missing from distributed models to date, namely the effects of debris cover. Many glacier ablation zones are mantled in near-continuous blankets of rock debris, and debris-covered glaciers are important drivers of the water cycle in the European Alps, Andes and Himalayas. Moreover, debris covers have been seen to expand in recent years, so it is essential to assess exactly how the presence of debris may affect a glacier’s surface energy balance and potential responses to climate changes. The effects of a debris cover are complicated by the varying surface roughness, albedo and thermal properties of the debris in question, but generally a debris cover reduces glacier melt rate by insulating the glacier surface from direct solar radiation. Even on glaciers where the debris cover is not continuous, isolated patches of debris caused by rockfalls can affect the glacier evolution by introducing differential ablation across the glacier surface, thus creating ice-cored moraines that may persist after ‘clean’ parts of the glacier have wasted away. This paper presents the results of incorporating a one-dimensional ‘debris energy balance model’ called DEB-Model (Reid and Brock 2010) into a distributed melt model for Haut Glacier d’Arolla, Switzerland. DEB-Model numerically estimates debris surface temperature by considering the balance of heat fluxes at the air-debris interface, then calculates heat conduction through the debris in order to estimate melt rates at the
Energy Technology Data Exchange (ETDEWEB)
Razik, H. [Universite Henri Poincare, GREEN, CNRS-UMR 7037, BP 239, F-54506 Vandoeuvre-les-Nancy Cedex (France); Henao, H. [University of Picardie, CREA, 33 rue Saint Leu, F-80039 Amiens Cedex 1 (France); Carlson, R. [GRUCAD/CTC/UFSC, Campus Universitario, C.P. 436, Florianopolis - SC, 88040-900 (Brazil)
2009-01-15
This paper presents a mathematical model of a three-phase induction motor taking into consideration the interbar contacts. Several models have been available in the references. However, they consider the rotor of the induction motor as being constituted either a three-phase or a squirrel cage even if it operates under stator and/or rotor faults condition. Nonetheless, the contact between a bar and the iron core for the machine has to be considered, especially when a rotor fault occurs. It is obvious that rotor currents are under the influence of rotor constitution materials. So, the paper aim's concerns a transient model of the induction motors which can consider the rotor broken bars defect. Despite its increasing complexity, it could be able to provide with useful indications for diagnostic purposes. This model is advocated for the simulation of motors behavior under rotor defect which takes into account the interbar currents. The proposed technique is based on the mesh model analysis of the squirrel cage. As low power induction motors are prevalent in industrial plants, we pay a special attention on them. Notwithstanding, additional currents are due to the contact between the non-insulated bar constituting the squirrel cage to the rotor iron core. The monitoring of induction motors is predominantly made through the stator current analysis of the motor when it operates at nominal condition. Moreover, this one is observed in steady state operating system, knowing that the motor is generally fed by a sinusoidal supply. Consequently, simulation results showed in this paper prove the effectiveness of the proposed approach, and the impact of interbar resistance both on the model and the line current spectrum for the diagnostic. An experimental test proves the effectiveness of this model. (author)
Ward, Logan; Liu, Ruoqian; Krishna, Amar; Hegde, Vinay I.; Agrawal, Ankit; Choudhary, Alok; Wolverton, Chris
2017-07-01
While high-throughput density functional theory (DFT) has become a prevalent tool for materials discovery, it is limited by the relatively large computational cost. In this paper, we explore using DFT data from high-throughput calculations to create faster, surrogate models with machine learning (ML) that can be used to guide new searches. Our method works by using decision tree models to map DFT-calculated formation enthalpies to a set of attributes consisting of two distinct types: (i) composition-dependent attributes of elemental properties (as have been used in previous ML models of DFT formation energies), combined with (ii) attributes derived from the Voronoi tessellation of the compound's crystal structure. The ML models created using this method have half the cross-validation error and similar training and evaluation speeds to models created with the Coulomb matrix and partial radial distribution function methods. For a dataset of 435 000 formation energies taken from the Open Quantum Materials Database (OQMD), our model achieves a mean absolute error of 80 meV/atom in cross validation, which is lower than the approximate error between DFT-computed and experimentally measured formation enthalpies and below 15% of the mean absolute deviation of the training set. We also demonstrate that our method can accurately estimate the formation energy of materials outside of the training set and be used to identify materials with especially large formation enthalpies. We propose that our models can be used to accelerate the discovery of new materials by identifying the most promising materials to study with DFT at little additional computational cost.
Kumar, P.; Wiltshire, A.; Asharaf, S.; Ahrens, B.; Lucas-Picher, P.; Christensen, J. H.; Gobiet, A.; Saeed, F.; Hagemann, S.; Jacob, D.
2011-12-01
This study presents the possible regional climate change over SA with a focus over India as simulated by three very-high-resolution regional climate models. The models are driven by the same lateral boundary conditions from two global models (ECHAM5-MPIOM and HadCM3) under the IPCC AR4 SRES A1B scenario at horizontal resolution of ~25km, except one model which is simulated for only one GCM. The results are presented for two time slices 2021-2050 and 2070-2099. The analysis concentrates along precipitation and temperature over land and focuses mainly on the monsoon season. The circulation parameter is also discussed. In general all models show a clear signal of gradual wide-spread warming throughout the 21st century. The ensemble-mean warming evident at the end of 2050 is 1-2K, whereas it is 3-5K at the end of century. The projected pattern of the precipitation change shows spatial variability. The increase in precipitation is noticed over peninsular and coastal areas and no change or decrease over areas away from the ocean. The influence of the driving GCM on projected precipitation change simulated with each RCM is as strong as the variability among the RCMs driven with one GCM. Some results of the first uncertainties assessment are also presented.
Directory of Open Access Journals (Sweden)
Rutao Luo
Full Text Available Mathematical models based on ordinary differential equations (ODE have had significant impact on understanding HIV disease dynamics and optimizing patient treatment. A model that characterizes the essential disease dynamics can be used for prediction only if the model parameters are identifiable from clinical data. Most previous parameter identification studies for HIV have used sparsely sampled data from the decay phase following the introduction of therapy. In this paper, model parameters are identified from frequently sampled viral-load data taken from ten patients enrolled in the previously published AutoVac HAART interruption study, providing between 69 and 114 viral load measurements from 3-5 phases of viral decay and rebound for each patient. This dataset is considerably larger than those used in previously published parameter estimation studies. Furthermore, the measurements come from two separate experimental conditions, which allows for the direct estimation of drug efficacy and reservoir contribution rates, two parameters that cannot be identified from decay-phase data alone. A Markov-Chain Monte-Carlo method is used to estimate the model parameter values, with initial estimates obtained using nonlinear least-squares methods. The posterior distributions of the parameter estimates are reported and compared for all patients.
Kinetic modelling of anaerobic hydrolysis of solid wastes, including disintegration processes
Energy Technology Data Exchange (ETDEWEB)
García-Gen, Santiago [Department of Chemical Engineering, Institute of Technology, University of Santiago de Compostela, 15782 Santiago de Compostela (Spain); Sousbie, Philippe; Rangaraj, Ganesh [INRA, UR50, Laboratoire de Biotechnologie de l’Environnement, Avenue des Etangs, Narbonne F-11100 (France); Lema, Juan M. [Department of Chemical Engineering, Institute of Technology, University of Santiago de Compostela, 15782 Santiago de Compostela (Spain); Rodríguez, Jorge, E-mail: jrodriguez@masdar.ac.ae [Department of Chemical Engineering, Institute of Technology, University of Santiago de Compostela, 15782 Santiago de Compostela (Spain); Institute Centre for Water and Environment (iWater), Masdar Institute of Science and Technology, PO Box 54224 Abu Dhabi (United Arab Emirates); Steyer, Jean-Philippe; Torrijos, Michel [INRA, UR50, Laboratoire de Biotechnologie de l’Environnement, Avenue des Etangs, Narbonne F-11100 (France)
2015-01-15
Highlights: • Fractionation of solid wastes into readily and slowly biodegradable fractions. • Kinetic coefficients estimation from mono-digestion batch assays. • Validation of kinetic coefficients with a co-digestion continuous experiment. • Simulation of batch and continuous experiments with an ADM1-based model. - Abstract: A methodology to estimate disintegration and hydrolysis kinetic parameters of solid wastes and validate an ADM1-based anaerobic co-digestion model is presented. Kinetic parameters of the model were calibrated from batch reactor experiments treating individually fruit and vegetable wastes (among other residues) following a new protocol for batch tests. In addition, decoupled disintegration kinetics for readily and slowly biodegradable fractions of solid wastes was considered. Calibrated parameters from batch assays of individual substrates were used to validate the model for a semi-continuous co-digestion operation treating simultaneously 5 fruit and vegetable wastes. The semi-continuous experiment was carried out in a lab-scale CSTR reactor for 15 weeks at organic loading rate ranging between 2.0 and 4.7 g VS/L d. The model (built in Matlab/Simulink) fit to a large extent the experimental results in both batch and semi-continuous mode and served as a powerful tool to simulate the digestion or co-digestion of solid wastes.
A void ratio dependent water retention curve model including hydraulic hysteresis
Directory of Open Access Journals (Sweden)
Pasha Amin Y.
2016-01-01
Full Text Available Past experimental evidence has shown that Water Retention Curve (WRC evolves with mechanical stress and structural changes in soil matrix. Models currently available in the literature for capturing the volume change dependency of WRC are mainly empirical in nature requiring an extensive experimental programme for parameter identification which renders them unsuitable for practical applications. In this paper, an analytical model for the evaluation of the void ratio dependency of WRC in deformable porous media is presented. The approach proposed enables quantification of the dependency of WRC on void ratio solely based on the form of WRC at the reference void ratio and requires no additional parameters. The effect of hydraulic hysteresis on the evolution process is also incorporated in the model, an aspect rarely addressed in the literature. Expressions are presented for the evolution of main and scanning curves due to loading and change in the hydraulic path from scanning to main wetting/drying and vice versa as well as the WRC parameters such as air entry value, air expulsion value, pore size distribution index and slope of the scanning curve. The model is validated using experimental data on compacted and reconstituted soils subjected to various hydro-mechanical paths. Good agreement is obtained between model predictions and experimental data in all the cases considered.
Dörr, Aaron; Mehdizadeh, Amirfarhang
2012-01-01
Based on the notion of a construction process consisting of the stepwise addition of particles to the pure fluid, a discrete model for the apparent viscosity as well as for the maximum packing fraction of polydisperse suspensions of spherical, non-colloidal particles is derived. The model connects the approaches by Bruggeman and Farris and is valid for large size ratios of consecutive particle classes during the construction process. Furthermore, a new general form of the well-known Krieger equation allowing for the choice of a second-order Taylor coefficient for the volume fraction is proposed and then applied as a monodisperse reference equation in the course of polydisperse modeling. By applying the polydisperse viscosity model to two different particle size distributions (Rosin-Rammler and uniform distribution), the influence of polydispersity on the apparent viscosity is examined. The extension of the model to the case of small size ratios as well as to the inclusion of shear rate effects is left for fut...
Complete Loss and Thermal Model of Power Semiconductors Including Device Rating Information
DEFF Research Database (Denmark)
Ma, Ke; Bahman, Amir Sajjad; Beczkowski, Szymon;
2015-01-01
loading but also the device rating as input variables. The quantified correlation between the power loss, thermal impedance and silicon area of Insulated Gate Bipolar Transistor (IGBT) is mathematically established. By this new modeling approach, all factors that have impacts to the loss and thermal......Thermal loading of power devices are closely related to the reliability performance of the whole converter system. The electrical loading and device rating are both important factors that determine the loss and thermal behaviors of power semiconductor devices. In the existing loss and thermal...... models, only the electrical loadings are focused and treated as design variables, while the device rating is normally pre-defined by experience with limited design flexibility. Consequently, a more complete loss and thermal model is proposed in this paper, which takes into account not only the electrical...
A Simple Model of Fields Including the Strong or Nuclear Force and a Cosmological Speculation
Directory of Open Access Journals (Sweden)
David L. Spencer
2016-10-01
Full Text Available Reexamining the assumptions underlying the General Theory of Relativity and calling an object's gravitational field its inertia, and acceleration simply resistance to that inertia, yields a simple field model where the potential (kinetic energy of a particle at rest is its capacity to move itself when its inertial field becomes imbalanced. The model then attributes electromagnetic and strong forces to the effects of changes in basic particle shape. Following up on the model's assumption that the relative intensity of a particle's gravitational field is always inversely related to its perceived volume and assuming that all black holes spin, may create the possibility of a cosmic rebound where a final spinning black hole ends with a new Big Bang.
Numerical models of single- and double-negative metamaterials including viscous and thermal losses
DEFF Research Database (Denmark)
Cutanda Henriquez, Vicente; Sánchez-Dehesa, José
2017-01-01
Negative index acoustic metamaterials are artificial structures made of subwavelength units arranged in a lattice, whose effective acoustic parameters, bulk modulus and mass density, can be negative. In these materials, sound waves propagate inside the periodic structure, assumed rigid, showing...... extraordinary properties. We are interested in two particular cases: a double-negative metamaterial, where both parameters are negative at some frequencies, and a single-negative metamaterial with negative bulk modulus within a broader frequency band. In previous research involving the double......-negative metamaterial, numerical models with viscous and thermal losses were used to explain that the extraordinary behavior, predicted by analytical models and numerical simulations with no losses, disappeared when the metamaterial was measured in physical setups. The improvement of the models is allowing now a more...
Energy Technology Data Exchange (ETDEWEB)
Chortis, D I; Chrysochoidis, N A; Saravanos, D A [Department of Mechanical Engineering and Aeronautics, University of Patras, Patras 26500 (Greece)
2007-07-15
The paper presents a brief description of composite damping mechanics for blade sections of arbitrary lamination and geometry. A damped 3-D shear beam element is presented enabling the assembly of damped structural dynamic models of blades with hollow multi-cell tubular laminated sections. Emphasis is placed to the inclusion of composite material coupling effects, first in the blade section stiffness and damping matrices and finally into the stiffness and damping matrices of the finite element. Evaluations of the beam element are presented, to quantify the material coupling effect on composite beams of simple box sections. Correlations between predicted and measured modal frequencies and damping values in small model Glass/Epoxy are also shown. Finally, the damped modal characteristics of a 35m realistic wind-turbine blade model design, are predicted.
A study of a hamiltonian model for martensitic phase transformations including microkinetic energy
Theil, F
1998-01-01
How can a system in a macroscopically stable state explore energetically more favorable states, which are far away from the current equilibrium state? Based on continuum mechanical considerations we derive a Boussinesq-type equation which models the dynamics of martensitic phase transformations. The solutions of the system, which we refer to as microkinetically regularized wave equation exhibit strong oscillations after short times, thermalization can be confirmed. That means that macroscopic fluctuations of the solutions decay at the benefit of microscopic fluctuations. First analytical and numerical results on the propagation of phase boundaries and thermalization effects are presented. Despite the fact that model is conservative, it exhibits the hysteretic behavior. Such a behavior is usually interpreted in macroscopic models in terms of dissipative threshold which the driving force has to overcome to ensure that the phase transformation proceeds. The threshold value depends on the amount of the transforme...
Hybrid Model Representation of a TLP Including Flexible Topsides in Non-Linear Regular Waves
Directory of Open Access Journals (Sweden)
Christof Wehmeyer
2014-08-01
Full Text Available The rising demand for renewable energy solutions is forcing the established industries to expand and continue evolving. For the wind energy sector, the vast resources in deep sea locations have encouraged research towards the installation of turbines in deeper waters. One of the most promising technologies able to solve this challenge is the floating wind turbine foundation. For the ultimate limit state, where higher order wave loads have a significant influence, a design tool that couples non-linear excitations with structural dynamics is required. To properly describe the behavior of such a structure, a numerical model is proposed and validated by physical test results. The model is applied to a case study of a tension leg platform with a flexible topside mimicking the tower and a lumped mass mimicking the rotor-nacelle assembly. The model is additionally compared to current commercial software, where the need for the coupled higher order dynamics proposed in this paper becomes evident.
Loss and thermal model for power semiconductors including device rating information
DEFF Research Database (Denmark)
Ma, Ke; Bahman, Amir Sajjad; Beczkowski, Szymon;
2014-01-01
The electrical loading and device rating are both important factors that determine the loss and thermal behaviors of power semiconductor devices. In the existing loss and thermal models, only the electrical loadings are focused and treated as design variables, while the device rating is normally...... pre-defined by experience with poor design flexibility. Consequently a more complete loss and thermal model is proposed in this paper, which takes into account not only the electrical loading but also the device rating as input variables. The quantified correlation between the power loss, thermal...... impedance and silicon area of Insulated Gate Bipolar Transistor (IGBT) is mathematically established. By this new modeling approach, all factors that have impacts to the loss and thermal profiles of power devices can be accurately mapped, enabling more design freedom to optimize the efficiency and thermal...
Complete Loss and Thermal Model of Power Semiconductors Including Device Rating Information
DEFF Research Database (Denmark)
Ma, Ke; Bahman, Amir Sajjad; Beczkowski, Szymon
2015-01-01
profiles of the power devices can accurately be mapped, enabling more design freedom to optimize the efficiency and thermal loading of the power converter. The proposed model can be further improved by experimental tests, and it is well agreed by both circuit and Finite Element Method (FEM) simulation......Thermal loading of power devices are closely related to the reliability performance of the whole converter system. The electrical loading and device rating are both important factors that determine the loss and thermal behaviors of power semiconductor devices. In the existing loss and thermal...... models, only the electrical loadings are focused and treated as design variables, while the device rating is normally pre-defined by experience with limited design flexibility. Consequently, a more complete loss and thermal model is proposed in this paper, which takes into account not only the electrical...
Loss and thermal model for power semiconductors including device rating information
DEFF Research Database (Denmark)
Ma, Ke; Bahman, Amir Sajjad; Beczkowski, Szymon
2014-01-01
impedance and silicon area of Insulated Gate Bipolar Transistor (IGBT) is mathematically established. By this new modeling approach, all factors that have impacts to the loss and thermal profiles of power devices can be accurately mapped, enabling more design freedom to optimize the efficiency and thermal......The electrical loading and device rating are both important factors that determine the loss and thermal behaviors of power semiconductor devices. In the existing loss and thermal models, only the electrical loadings are focused and treated as design variables, while the device rating is normally...... pre-defined by experience with poor design flexibility. Consequently a more complete loss and thermal model is proposed in this paper, which takes into account not only the electrical loading but also the device rating as input variables. The quantified correlation between the power loss, thermal...
Groleau, Julie; Marecaux, Christophe; Payrard, Natacha; Segaud, Brice; Rochette, Michel; Perrier, Pascal; Payan, Yohan
2008-01-01
A 3D biomechanical finite element model of the face is presented. Muscles are represented by piece-wise uniaxial tension cable elements linking the insertion points. Such insertion points are specific entities differing from nodes of the finite element mesh, which makes possible to change either the mesh or the muscle implementation totally independently of each other. Lip/teeth and upper lip/lower lip contacts are also modeled. Simulations of smiling and of an Orbicularis Oris activation are presented and interpreted. The importance of a proper account of contacts and of an accurate anatomical description is shown
European air quality modelled by CAMx including the volatility basis set scheme
Directory of Open Access Journals (Sweden)
G. Ciarelli
2015-12-01
Full Text Available Four periods of EMEP (European Monitoring and Evaluation Programme intensive measurement campaigns (June 2006, January 2007, September–October 2008 and February–March 2009 were modelled using the regional air quality model CAMx with VBS (Volatility Basis Set approach for the first time in Europe within the framework of the EURODELTA-III model intercomparison exercise. More detailed analysis and sensitivity tests were performed for the period of February–March 2009 and June 2006 to investigate the uncertainties in emissions as well as to improve the modelling of organic aerosols (OA. Model performance for selected gas phase species and PM2.5 was evaluated using the European air quality database Airbase. Sulfur dioxide (SO2 and ozone (O3 were found to be overestimated for all the four periods with O3 having the largest mean bias during June 2006 and January–February 2007 periods (8.93 and 12.30 ppb mean biases, respectively. In contrast, nitrogen dioxide (NO2 and carbon monoxide (CO were found to be underestimated for all the four periods. CAMx reproduced both total concentrations and monthly variations of PM2.5 very well for all the four periods with average biases ranging from −2.13 to 1.04 μg m-3. Comparisons with AMS (Aerosol Mass Spectrometer measurements at different sites in Europe during February–March 2009, showed that in general the model over-predicts the inorganic aerosol fraction and under-predicts the organic one, such that the good agreement for PM2.5 is partly due to compensation of errors. The effect of the choice of volatility basis set scheme (VBS on OA was investigated as well. Two sensitivity tests with volatility distributions based on previous chamber and ambient measurements data were performed. For February–March 2009 the chamber-case reduced the total OA concentrations by about 43 % on average. On the other hand, a test based on ambient measurement data increased OA concentrations by about 47 % for the same
Viscoelastic Model of Cross-Linked Polyethylene Including Effects of Temperature and Crystallinity
Olasz, L.; Gudmundson, P.
2005-12-01
Characterization of the mechanical behavior of cross-linked polyethylene (XLPE) commonly used in high voltage cable insulation was performed by an extensive set of isothermal uniaxial tensile relaxation tests. Tensile relaxation experiments were complemented by pressure-volume-temperature experiments as well as density and crystallinity measurements. Based on the experimental results, a viscoelastic power law model with four parameters was formulated, incorporating temperature and crystallinity dependence. It was found that a master curve can be developed by both horizontal and vertical shifting of the relaxation curves. The model was evaluated by making comparisons of the predicted stress responses with the measured responses in relaxation tests with transient temperature histories.
Ng, Jonathan; Hakim, Ammar; Bhattacharjee, Amitava; Stanier, Adam; Daughton, William; Wang, Liang; Germaschewski, Kai
2015-01-01
As modeling of collisionless magnetic reconnection in most space plasmas with realistic parameters is beyond the capability of today's simulations, due to the separation between global and kinetic length scales, it is important to establish scaling relations in model problems so as to extrapolate to realistic scales. Recently, large scale particle-in-cell (PIC) simulations of island coalescence have shown that the time averaged reconnection rate decreases with system size, while fluid systems at such large scales in the Hall regime have not been studied. Here we perform the complementary resistive MHD, Hall MHD and two fluid simulations using a ten-moment model with the same geometry. In contrast to the standard Harris sheet reconnection problem, Hall MHD is insufficient to capture the physics of the reconnection region. Additionally, motivated by the results of a recent set of hybrid simulations which show the importance of ion kinetics in this geometry, we evaluate the efficacy of the ten-moment model in re...
Situational effects of the school factors included in the dynamic model of educational effectiveness
Creerners, Bert; Kyriakides, Leonidas
2009-01-01
We present results of a longitudinal study in which 50 schools, 113 classes and 2,542 Cypriot primary students participated. We tested the validity of the dynamic model of educational effectiveness and especially its assumption that the impact of school factors depends on the current situation of th
Gövert, S.; Mira, D.; Kok, J.B.W.; Vázquez, M.; Houzeaux, G.
2015-01-01
The present work addresses the coupling of a flamelet database, to a low-Mach approximation of the Navier–Stokes equations using scalar controlling variables. The model is characterized by the chemistry tabulation based on laminar premixed flamelets in combination with an optimal choice of the react
Kinetic modelling of anaerobic hydrolysis of solid wastes, including disintegration processes.
García-Gen, Santiago; Sousbie, Philippe; Rangaraj, Ganesh; Lema, Juan M; Rodríguez, Jorge; Steyer, Jean-Philippe; Torrijos, Michel
2015-01-01
A methodology to estimate disintegration and hydrolysis kinetic parameters of solid wastes and validate an ADM1-based anaerobic co-digestion model is presented. Kinetic parameters of the model were calibrated from batch reactor experiments treating individually fruit and vegetable wastes (among other residues) following a new protocol for batch tests. In addition, decoupled disintegration kinetics for readily and slowly biodegradable fractions of solid wastes was considered. Calibrated parameters from batch assays of individual substrates were used to validate the model for a semi-continuous co-digestion operation treating simultaneously 5 fruit and vegetable wastes. The semi-continuous experiment was carried out in a lab-scale CSTR reactor for 15 weeks at organic loading rate ranging between 2.0 and 4.7 gVS/Ld. The model (built in Matlab/Simulink) fit to a large extent the experimental results in both batch and semi-continuous mode and served as a powerful tool to simulate the digestion or co-digestion of solid wastes.
New phases in an extended Hubbard model explicitly including atomic polarizabilities
Brink, van de J.; Meinders, M.B.J.; Lorenzana, J.; Eder, R.; Sawatzky, G.A.
1996-01-01
We consider the influence of a nearest-neighbor Coulomb interaction in an extended Hubbard model and introduce a new interaction term which simulates atomic polarizabilities. This has the effect of screening the on-site Coulomb interaction for charged excitations, unlike a neighbor Coulomb interacti
Modeling of etch profile evolution including wafer charging effects using self consistent ion fluxes
Energy Technology Data Exchange (ETDEWEB)
Hoekstra, R.J.; Kushner, M.J. [Univ. of Illinois, Urbana, IL (United States). Dept. of Electrical and Computer Engineering
1996-12-31
As high density plasma reactors become more predominate in industry, the need has intensified for computer aided design tools which address both equipment issues such as ion flux uniformity onto the water and process issues such etch feature profile evolution. A hierarchy of models has been developed to address these issues with the goal of producing a comprehensive plasma processing design capability. The Hybrid Plasma Equipment Model (HPEM) produces ion and neutral densities, and electric fields in the reactor. The Plasma Chemistry Monte Carlo Model (PCMC) determines the angular and energy distributions of ion and neutral fluxes to the wafer using species source functions, time dependent bulk electric fields, and sheath potentials from the HPEM. These fluxes are then used by the Monte Carlo Feature Profile Model (MCFP) to determine the time evolution of etch feature profiles. Using this hierarchy, the effects of physical modifications of the reactor, such as changing wafer clamps or electrode structures, on etch profiles can be evaluated. The effects of wafer charging on feature evolution are examined by calculating the fields produced by the charge deposited by ions and electrons within the features. The effect of radial variations and nonuniformity in angular and energy distribution of the reactive fluxes on feature profiles and feature charging will be discussed for p-Si etching in inductively-coupled plasma (ICP) sustained in chlorine gas mixtures. The effects of over- and under-wafer topography on etch profiles will also be discussed.
Surface-wave mode coupling : modelling and inverting waveforms including body-wave phases
Marquering, H.A.
1996-01-01
This thesis is concerned with a similar problem as addressed by Li & Tanimoto (1993) in the surfacewave mode approach. In this thesis it is shown that surface-wave mode coupling is required when body-wave phases in laterally heterogeneous media are modelled by surface-wave mode summation. An efficie
Energy Technology Data Exchange (ETDEWEB)
Ng, Jonathan; Huang, Yi-Min; Hakim, Ammar; Bhattacharjee, A. [Center for Heliophysics, Princeton Plasma Physics Laboratory, Princeton, New Jersey 08540 (United States); Stanier, Adam; Daughton, William [Los Alamos National Laboratory, Los Alamos, New Mexico 87545 (United States); Wang, Liang; Germaschewski, Kai [Space Science Center and Physics Department, University of New Hampshire, Durham, New Hampshire 03824 (United States)
2015-11-15
As modeling of collisionless magnetic reconnection in most space plasmas with realistic parameters is beyond the capability of today's simulations, due to the separation between global and kinetic length scales, it is important to establish scaling relations in model problems so as to extrapolate to realistic scales. Recently, large scale particle-in-cell simulations of island coalescence have shown that the time averaged reconnection rate decreases with system size, while fluid systems at such large scales in the Hall regime have not been studied. Here, we perform the complementary resistive magnetohydrodynamic (MHD), Hall MHD, and two fluid simulations using a ten-moment model with the same geometry. In contrast to the standard Harris sheet reconnection problem, Hall MHD is insufficient to capture the physics of the reconnection region. Additionally, motivated by the results of a recent set of hybrid simulations which show the importance of ion kinetics in this geometry, we evaluate the efficacy of the ten-moment model in reproducing such results.
DEFF Research Database (Denmark)
Rasmussen, Anders Rønne; Sørensen, Mads Peter; Gaididei, Yuri Borisovich
2010-01-01
A wave equation, that governs finite amplitude acoustic disturbances in a thermoviscous Newtonian fluid, and includes nonlinear terms up to second order, is proposed. The equation preserves the Hamiltonian structure of the fundamental fluid dynamical equations in the non dissipative limit. An exact...
Agarwalla, Sanjib Kumar; Raychaudhuri, Amitava
2007-01-01
We study the physics reach of an experiment where neutrinos produced in a beta-beam facility at CERN are observed in a large magnetized iron calorimeter (ICAL) at the India-based Neutrino Observatory (INO). The CERN-INO distance is close to the so-called "magic" baseline which helps evade some of the parameter degeneracies and allows for a better measurement of the neutrino mass hierarchy and $\\theta_{13}$.
DEFF Research Database (Denmark)
Hougaard, Jens Leth; Moreno-Ternero, Juan D.; Østerdal, Lars Peter Raahave
2013-01-01
We introduce a new operator for general rationing problems in which, besides conflicting claims, individual baselines play an important role in the rationing process. The operator builds onto ideas of composition, which are not only frequent in rationing, but also in related problems...... such as bargaining, choice, and queuing. We characterize the operator and show how it preserves some standard axioms in the literature on rationing. We also relate it to recent contributions in such literature....
A model for heterogeneous traffic flows including non-motorized vehicles
Energy Technology Data Exchange (ETDEWEB)
Oketch, T.G.
2001-07-01
This study is concerned with developing a traffic flow and emissions model suitable for heterogeneous traffic streams containing motorised and non-motorised vehicles. Such streams contain vehicle types such as private cars, buses and trucks as well as bicycles, motorcycles and other vehicular forms. The model covers the different vehicle types and allows for peculiar behaviours prevalent in such streams. In addition to an existing deterministic car following rule, the model incorporates detailed lateral movement algorithm with gradual lane change manoeuvres, the decisions of which are governed by fuzzy logic rules. For determination of pollutant emissions, the travel lane was divided into finite elements and total emissions aggregated for each element depending on the vehicle speeds and types. A methodology for estimation of emission rates, based on vehicle maintenance history, for countries without reliable inventories was proposed and used to obtain emission coefficients of CO, HC, NOx and Pb emissions in Kenya. In conclusion, the model has demonstrated that heterogeneous traffic can be effectively analysed by approaches that take their peculiar characteristics into consideration. In addition, it has also provided new insight in the performance and emission patterns of heterogeneous traffic streams which can be used to formulate regulatory directives governing the usage of lanes or provision of auxiliary carriageways for slower vehicles. (orig.) [German] In dieser Arbeit wurde ein Verkehrsfluss- und Emissions-Model fuer heterogene Verkehrsstroeme entwickelt. Solche Verkehrsstroeme enthalten nicht nur motorisierte Fahrzeuge wie Pkw, Lkw, Omnibus, Motorrad usw. sondern auch nicht-motorisierte Fahrzeuge wie Fahrrad und auch besondere Fahrzeugtypen, die auf Motorraedern oder Fahrraedern basieren. Im Modell wurden auch die entsprechenden besonderen Verhaeltnisse dieser Fahrzeugtypen beruecksichtigt. Die Bewegung von Fahrzeugen wurde in zwei Dimensionen modelliert. Auf
DEFF Research Database (Denmark)
Bollerslev, Tim; Andersen, Torben G.; Diebold, Francis X.
A rapidly growing literature has documented important improvements in financial return volatility measurement and forecasting via use of realized variation measures constructed from high-frequency returns coupled with simple modeling procedures. Building on recent theoretical results in Barndorff...... bond yield, we find that jumps are both highly prevalent and distinctly less persistent than the continuous sample path variation process. Moreover, many jumps appear directly associated with specific macroeconomic news announcements. Separating jump from non-jump movements in a simple...... but sophisticated volatility forecasting model, we find that almost all of the predictability in daily, weekly, and monthly return volatilities comes from the non-jump component. Our results thus set the stage for a number of interesting future econometric developments and important financial applications...
Lüdde, H. J.; Achenbach, A.; Kalkbrenner, T.; Jankowiak, H. C.; Kirchner, T.
2016-05-01
A recently introduced model to account for geometric screening corrections in an independent-atom-model description of ion-molecule collisions is applied to proton collisions from amino acids and DNA and RNA nucleobases. The correction coefficients are obtained from using a pixel counting method (PCM) for the exact calculation of the effective cross sectional area that emerges when the molecular cross section is pictured as a structure of (overlapping) atomic cross sections. This structure varies with the relative orientation of the molecule with respect to the projectile beam direction and, accordingly, orientation-independent total cross sections are obtained from averaging the pixel count over many orientations. We present net capture and net ionization cross sections over wide ranges of impact energy and analyze the strength of the screening effect by comparing the PCM results with Bragg additivity rule cross sections and with experimental data where available. Work supported by NSERC, Canada.
Benzekry, Sebastien
2010-01-01
Angiogenesis is a key process in the tumoral growth which allows the cancerous tissue to impact on its vasculature in order to improve the nutrient's supply and the metastatic process. In this paper, we introduce a model for the density of metastasis which takes into account for this feature. It is a two dimensional structured equation with a vanishing velocity field and a source term on the boundary. We present here the mathematical analysis of the model, namely the well-posedness of the equation and the asymptotic behavior of the solutions, whose natural regularity led us to investigate some basic properties of the space $\\Wd(\\Om)=\\{V\\in L^1;\\;\\div(GV)\\in L^1\\}$, where $G$ is the velocity field of the equation.
A model for thermal oxidation of Si and SiC including material expansion
Energy Technology Data Exchange (ETDEWEB)
Christen, T., E-mail: thomas.christen@ch.abb.com; Ioannidis, A. [ABB Corporate Research, Segelhofstrasse 1K, CH-5405 Baden (Switzerland); Winkelmann, C. [ETH Zürich, Seminar for Applied Mathematics, Rämistrasse 101, CH-8092 Zürich (Switzerland)
2015-02-28
A model based on drift-diffusion-reaction kinetics for Si and SiC oxidation is discussed, which takes the material expansion into account with an additional convection term. The associated velocity field is determined self-consistently from the local reaction rate. The approach allows a calculation of the densities of volatile species in an nm-resolution at the oxidation front. The model is illustrated with simulation results for the growth and impurity redistribution during Si oxidation and for carbon and silicon emission during SiC oxidation. The approach can be useful for the prediction of Si and/or C interstitial distribution, which is particularly relevant for the quality of metal-oxide-semiconductor electronic devices.
A roller chain drive model including contact with guide-bars
DEFF Research Database (Denmark)
Pedersen, Sine Leergaard; Hansen, John Michael; Ambrósio, J. A. C.
2004-01-01
and continuous force methods, respectively. In the unilateral constraint methodology the kinematic constraints are introduced in the system anytime a contact between the rollers and the sprockets is detected. The condition for the constraint addition is based on the relative distance between the roller centre...... and the sprocket centre, i.e. a constraint is added when such distance is less than the pitch radius. The unilateral kinematic constraint is removed when its associated constraint reaction force, applied on the roller, is in the direction of the root of the sprocket teeth. In order to improve the numerical...... as continuous force. The model of the roller-chain drive now proposed departs from an earlier model where two contact/impact methods are proposed to describe the contact between the rollers of the chain and the teeth of the sprockets. These different formulations are based on unilateral constraints...
DEFF Research Database (Denmark)
Bollerslev, Tim; Andersen, Torben G.; Diebold, Francis X.
-Nielsen and Shephard (2004a, 2005) for related bi-power variation measures, the present paper provides a practical and robust framework for non-parametrically measuring the jump component in asset return volatility. In an application to the DM/$ exchange rate, the S&P500 market index, and the 30-year U.S. Treasury......A rapidly growing literature has documented important improvements in financial return volatility measurement and forecasting via use of realized variation measures constructed from high-frequency returns coupled with simple modeling procedures. Building on recent theoretical results in Barndorff...... but sophisticated volatility forecasting model, we find that almost all of the predictability in daily, weekly, and monthly return volatilities comes from the non-jump component. Our results thus set the stage for a number of interesting future econometric developments and important financial applications...
Energy Technology Data Exchange (ETDEWEB)
Frankowski, Marek, E-mail: mfrankow@agh.edu.pl; Czapkiewicz, Maciej; Skowronski, Witold; Stobiecki, Tomasz
2014-02-15
We present a model introducing the Landau–Lifshitz–Gilbert equation with a Slonczewski's Spin-Transfer-Torque (STT) component in order to take into account spin polarized current influence on the magnetization dynamics, which was developed as an Object Oriented MicroMagnetic Framework extension. We implement the following computations: magnetoresistance of vertical channels is calculated from the local spin arrangement, local current density is used to calculate the in-plane and perpendicular STT components as well as the Oersted field, which is caused by the vertical current flow. The model allows for an analysis of all listed components separately, therefore, the contribution of each physical phenomenon in dynamic behavior of Magnetic Tunnel Junction (MTJ) magnetization is discussed. The simulated switching voltage is compared with the experimental data measured in MTJ nanopillars.
Institute of Scientific and Technical Information of China (English)
郭金运; 陶华学
2003-01-01
In order to process different kinds of observing data with different precisions, a new solution model of nonlinear dynamic integral least squares adjustment was put forward, which is not dependent on their derivatives. The partial derivative of each component in the target function is not computed while iteratively solving the problem. Especially when the nonlinear target function is more complex and very difficult to solve the problem, the method can greatly reduce the computing load.
Ricks, Trenton M.; Lacy, Thomas E., Jr.; Bednarcyk, Brett A.; Arnold, Steven M.; Hutchins, John W.
2014-01-01
A multiscale modeling methodology was developed for continuous fiber composites that incorporates a statistical distribution of fiber strengths into coupled multiscale micromechanics/finite element (FE) analyses. A modified two-parameter Weibull cumulative distribution function, which accounts for the effect of fiber length on the probability of failure, was used to characterize the statistical distribution of fiber strengths. A parametric study using the NASA Micromechanics Analysis Code with the Generalized Method of Cells (MAC/GMC) was performed to assess the effect of variable fiber strengths on local composite failure within a repeating unit cell (RUC) and subsequent global failure. The NASA code FEAMAC and the ABAQUS finite element solver were used to analyze the progressive failure of a unidirectional SCS-6/TIMETAL 21S metal matrix composite tensile dogbone specimen at 650 degC. Multiscale progressive failure analyses were performed to quantify the effect of spatially varying fiber strengths on the RUC-averaged and global stress-strain responses and failure. The ultimate composite strengths and distribution of failure locations (predominately within the gage section) reasonably matched the experimentally observed failure behavior. The predicted composite failure behavior suggests that use of macroscale models that exploit global geometric symmetries are inappropriate for cases where the actual distribution of local fiber strengths displays no such symmetries. This issue has not received much attention in the literature. Moreover, the model discretization at a specific length scale can have a profound effect on the computational costs associated with multiscale simulations.models that yield accurate yet tractable results.
A quark model calculation of yy->pipi including final-state interactions
Blundell, H G; Hay, G; Swanso, E
2000-01-01
A quark model calculation of the processes yy->pi+pi- and yy->pipi is performed. At tree level, only charged pions couple to the initial state photons and neutral pions are not exceeded in the final state. However a small but significant cross section is observed. We demonstrate that this may be accounted for by a rotation in isospin space induced by final-state interactions.
2011-03-01
Hypothesized that snow plows wear down mountain road pavement markings. 2007 Craig et al. -Edge lines degrade slower than center/skip lines 2007...retroreflectivity to create the models. They discovered that paint pavement markings last 80% longer on Portland Cement Concrete than Asphalt Concrete at low AADT...retroreflectivity, while yellow markings lost 21%. Lu and Barter attributed the sizable degradation to snow removal, sand application, and studded
Energy Technology Data Exchange (ETDEWEB)
Seiler, J.M.; Bonnet, J.M.; Bernaz, L. [CEA Grenoble (France)
2001-07-01
Extensive studies have been performed to investigate the heat transfer within a molten corium pool (homogeneous, stratified and with miscibility gap): Synthesis of heat transfer correlations in molten pool (homogeneous and stratified), Focusing effect in stratified metal layer, DNS analysis of Rayleigh Benard instabilities at the top boundary; interpretation of the different convection regimes and exponents affecting the Rayleigh number in the heat transfer correlations, Molten pool model for corium presenting a miscibility gap. Condition for de-stratification. (authors)
Modeling the Corona and Solar Wind using ADAPT Maps that Include Far-Side Observations
2013-11-01
document for any purpose other than Government procurement does not in any way obligate the U.S. Government. The fact that the Government formulated...Government’s approval or disapproval of its ideas or findings. Approved for public release; distribution is unlimited. REPORT DOCUMENTATION PAGE...Los Alamos National Laboratory ( LANL ) and the National Solar Observatory (NSO), has developed a model that produces more realistic estimates of the
Numerical modelling of the transport of trace gases including methane in the subsurface of Mars
Stevens, Adam H.; Patel, Manish R.; Lewis, Stephen R.
2015-04-01
We model the transport of gas through the martian subsurface in order to quantify the timescales of release of a trace gas with a source at depth using a Fickian model of diffusion through a putative martian regolith column. The model is then applied to the case of methane to determine if diffusive transport of gas can explain previous observations of methane in the martian atmosphere. We investigate which parameters in the model have the greatest effect on transport timescales and show that the calculated diffusivity is very sensitive to the pressure profile of the subsurface, but relatively insensitive to the temperature profile, though diffusive transport may be affected by other temperature dependent properties of the subsurface such as the local vapour pressure. Uncertainties in the structure and physical conditions of the martian subsurface also introduce uncertainties in the timescales calculated. It was found that methane may take several hundred thousand Mars-years to diffuse from a source at depth. Purely diffusive transport cannot explain transient release that varies on timescales of less than one martian year from sources such as serpentinization or methanogenic organisms at depths of more than 2 km. However, diffusion of gas released by the destabilisation of methane clathrate hydrates close to the surface, for example caused by transient mass wasting events or erosion, could produce a rapidly varying flux of methane into the atmosphere of more than 10-3 kg m-2 s-1 over a duration of less than half a martian year, consistent with observations of martian methane variability. Seismic events, magmatic intrusions or impacts could also potentially produce similar patterns of release, but are far more complex to simulate.
Numerical modeling of shallow flows including bottom topography and friction effects
Lukácová-Medvid'ová, Maria
2004-01-01
The aim of the paper is numerical modeling of the shallow water equation with source terms by genuinely multdimensional finite volume evolution Galerkin schemes. The shallow water system, or its one-dimensional analogy the Saint-Venant equation, is used extensively for numerical simulation of natural rivers. Mathematically the shallow water system belongs to the class of balance laws. A special treatment of the source terms describing the bottom topography as well as frictions effects is nece...
A numerical model of the ionosphere, including the E-region above EISCAT
Directory of Open Access Journals (Sweden)
P.-Y. Diloy
Full Text Available It has been previously demonstrated that a two-ion (O^{+} and H^{+} 8-moment time-dependent fluid model was able to reproduce correctly the ionospheric structure in the altitude range probed by the EISCAT-VHF radar. In the present study, the model is extended down to the E-region where molecular ion chemistry (NO^{+} and O^{+}_{2}, essentially prevails over transport; EISCAT-UHF observations confirmed previous theoretical predictions that during events of intense E×B induced convection drifts, molecular ions (mainly NO^{+} predominate over O^{+} ions up to altitudes of 300 km. In addition to this extension of the model down to the E-region, the ionization and heating resulting from both solar insolation and particle precipitation is now taken into account in a consistent manner through a complete kinetic transport code. The effects of E×B induced convection drifts on the E- and F-region are presented: the balance between O^{+} and NO^{+} ions is drastically affected; the electric field acts to deplete the O^{+} ion concentration. The [NO^{+}]/[O^{+}] transition altitude varies from 190 km to 320 km as the perpendicular electric field increases from 0 to 100 mV m^{-1}. An interesting additional by-product of the model is that it also predicts the presence of a noticeable fraction of N^{+} ions in the topside ionosphere in good agreement with Retarding Ion Mass Spectrometer measurements onboard Dynamic Explorer.
Climate change impact modelling needs to include cross-sectoral interactions
Harrison, Paula A.; Dunford, Robert W.; Holman, Ian P.; Rounsevell, Mark D. A.
2016-09-01
Climate change impact assessments often apply models of individual sectors such as agriculture, forestry and water use without considering interactions between these sectors. This is likely to lead to misrepresentation of impacts, and consequently to poor decisions about climate adaptation. However, no published research assesses the differences between impacts simulated by single-sector and integrated models. Here we compare 14 indicators derived from a set of impact models run within single-sector and integrated frameworks across a range of climate and socio-economic scenarios in Europe. We show that single-sector studies misrepresent the spatial pattern, direction and magnitude of most impacts because they omit the complex interdependencies within human and environmental systems. The discrepancies are particularly pronounced for indicators such as food production and water exploitation, which are highly influenced by other sectors through changes in demand, land suitability and resource competition. Furthermore, the discrepancies are greater under different socio-economic scenarios than different climate scenarios, and at the sub-regional rather than Europe-wide scale.
Kinetic model of water disinfection using peracetic acid including synergistic effects.
Flores, Marina J; Brandi, Rodolfo J; Cassano, Alberto E; Labas, Marisol D
2016-01-01
The disinfection efficiencies of a commercial mixture of peracetic acid against Escherichia coli were studied in laboratory scale experiments. The joint and separate action of two disinfectant agents, hydrogen peroxide and peracetic acid, were evaluated in order to observe synergistic effects. A kinetic model for each component of the mixture and for the commercial mixture was proposed. Through simple mathematical equations, the model describes different stages of attack by disinfectants during the inactivation process. Based on the experiments and the kinetic parameters obtained, it could be established that the efficiency of hydrogen peroxide was much lower than that of peracetic acid alone. However, the contribution of hydrogen peroxide was very important in the commercial mixture. It should be noted that this improvement occurred only after peracetic acid had initiated the attack on the cell. This synergistic effect was successfully explained by the proposed scheme and was verified by experimental results. Besides providing a clearer mechanistic understanding of water disinfection, such models may improve our ability to design reactors.
Directory of Open Access Journals (Sweden)
Mirka Mobilia
2017-01-01
Full Text Available In the last decades, there has been a widespread implementation of Green Infrastructures worldwide. Among these, green roofs appear to be particularly flexible sustainable drainage facilities. To predict their effectiveness for planning purposes, a tool is required that provides information as a function of local meteorological variables. Thus, a relatively simple daily scale, one-dimensional water balance approach has been proposed. The crucial evapotranspiration process, usually considered as a water balance dependent variable, is replaced here by empirical relationships providing an a-priori assessment of soil water losses through actual evapotranspiration. The modelling scheme, which under some simplification can be used without a calibration process, has been applied to experimental runoff data monitored at a green roof located near Bernkastel (Germany, between April 2005 and December 2006. Two different empirical relationships have been used to model actual evapotranspiration, considering a water availability limited and an energy limited scheme. Model errors quantification, ranging from 2% to 40% on the long-term scale and from 1% to 36% at the event scale, appear strongly related to the particularly considered relationship.
Campbell, C. L.; Brown, C. T. A.; Wood, K.; Moseley, H.
2016-11-01
Most existing theoretical models of photodynamic therapy (PDT) assume a uniform initial distribution of the photosensitive molecule, Protoporphyrin IX (PpIX). This is an adequate assumption when the prodrug is systematically administered; however for topical PDT this is no longer a valid assumption. Topical application and subsequent diffusion of the prodrug results in an inhomogeneous distribution of PpIX, especially after short incubation times, prior to light illumination. In this work a theoretical simulation of PDT where the PpIX distribution depends on the incubation time and the treatment modality is described. Three steps of the PpIX production are considered. The first is the distribution of the topically applied prodrug, the second in the conversion from the prodrug to PpIX and the third is the light distribution which affects the PpIX distribution through photobleaching. The light distribution is modelled using a Monte Carlo radiation transfer model and indicates treatment depths of around 2 mm during daylight PDT and approximately 3 mm during conventional PDT. The results suggest that treatment depths are not only limited by the light penetration but also by the PpIX distribution.
A stepped leader model for lightning including charge distribution in branched channels
Energy Technology Data Exchange (ETDEWEB)
Shi, Wei; Zhang, Li [School of Electrical Engineering, Shandong University, Jinan 250061 (China); Li, Qingmin, E-mail: lqmeee@ncepu.edu.cn [Beijing Key Lab of HV and EMC, North China Electric Power University, Beijing 102206 (China); State Key Lab of Alternate Electrical Power System with Renewable Energy Sources, Beijing 102206 (China)
2014-09-14
The stepped leader process in negative cloud-to-ground lightning plays a vital role in lightning protection analysis. As lightning discharge usually presents significant branched or tortuous channels, the charge distribution along the branched channels and the stochastic feature of stepped leader propagation were investigated in this paper. The charge density along the leader channel and the charge in the leader tip for each lightning branch were approximated by introducing branch correlation coefficients. In combination with geometric characteristics of natural lightning discharge, a stochastic stepped leader propagation model was presented based on the fractal theory. By comparing simulation results with the statistics of natural lightning discharges, it was found that the fractal dimension of lightning trajectory in simulation was in the range of that observed in nature and the calculation results of electric field at ground level were in good agreement with the measurements of a negative flash, which shows the validity of this proposed model. Furthermore, a new equation to estimate the lightning striking distance to flat ground was suggested based on the present model. The striking distance obtained by this new equation is smaller than the value estimated by previous equations, which indicates that the traditional equations may somewhat overestimate the attractive effect of the ground.
Numerical Modeling of the Surface Fatigue Crack Propagation Including the Closure Effect
Guchinsky, Ruslan; Petinov, Sergei
2016-01-01
Presently modeling of surface fatigue crack growth for residual life assessment of structural elements is almost entirely based on application of the Linear Elastic Fracture Mechanics (LEFM). Generally, it is assumed that the crack front does not essentially change its shape, although it is not always confirmed by experiment. Furthermore, LEFM approach cannot be applied when the stress singularity vanishes due to material plasticity, one of the leading factors associated with the material degradation and fracture. Also, evaluation of stress intensity factors meets difficulties associated with changes in the stress state along the crack front circumference. An approach proposed for simulation the evolution of surface cracks based on application of the Strain-life criterion for fatigue failure and of the finite element modeling of damage accumulation. It takes into account the crack closure effect, the nonlinear behavior of damage accumulation and material compliance increasing due to the damage advance. The damage accumulation technique was applied to model the semi-elliptical crack growth from the initial defect in the steel compact specimen. The results of simulation are in good agreement with the published experimental data.
Developing parameters for multi-mode ambient air models including the nanometer mode
Tronville, Paolo; Rivers, Richard
2017-06-01
The particle count, surface and mass in an occupied space can be modeled when the HVAC system airflows are known, along with the particle-size distribution for outdoor air, internal generation rates as a function of particle size, and the efficiency as a function of particle size for filters present. Outdoor air particle-size distribution is rarely available, but measures of particle mass concentration, PM2.5 and PM10, are often available for building locations. Outdoor air aerosol size distributions are well modeled by sums of two or three log-normal distributions, with essentially all mass in two larger modes. Studies have also shown that some mode parameters are, in general, related by simple functions. This paper shows how these relationships can be combined with known characteristics of PM2.5 and PM10 samplers to create reasonable inclusive models of outdoor air aerosol-size distributions. This information plus knowledge of indoor particle generation allows calculation of aerosol mass in occupied spaces. Estimation of parameters of aerosol modes with sizes below100 nm and measurement of filter efficiencies in that range are described.
Galactic habitable zone around M and FGK stars with chemical evolution models that include dust
Spitoni, E.; Gioannini, L.; Matteucci, F.
2017-09-01
Context. The Galactic habitable zone is defined as the region with a metallicity that is high enough to form planetary systems in which Earth-like planets could be born and might be capable of sustaining life. Life in this zone needs to survive the destructive effects of nearby supernova explosion events. Aims: Galactic chemical evolution models can be useful tools for studying the galactic habitable zones in different systems. Our aim here is to find the Galactic habitable zone using chemical evolution models for the Milky Way disk, adopting the most recent prescriptions for the evolution of dust and for the probability of finding planetary systems around M and FGK stars. Moreover, for the first time, we express these probabilities in terms of the dust-to-gas ratio of the interstellar medium in the solar neighborhood as computed by detailed chemical evolution models. Methods: At a fixed Galactic time and Galactocentric distance, we determined the number of M and FGK stars that host earths (but no gas giant planets) that survived supernova explosions, using the formalism of our Paper I. Results: The probabilities of finding terrestrial planets but not gas giant planets around M stars deviate substantially from the probabilities around FGK stars for supersolar values of [Fe/H]. For both FGK and M stars, the maximum number of stars hosting habitable planets is at 8 kpc from the Galactic Center when destructive effects by supernova explosions are taken into account. Currently, M stars with habitable planets are ≃10 times more frequent than FGK stars. Moreover, we provide a sixth-order polynomial fit (and a linear fit, but that is more approximated) for the relation found with chemical evolution models in the solar neighborhood between the [Fe/H] abundances and the dust-to-gas ratio. Conclusions: The most likely Galactic zone in which to find terrestrial habitable planets around M and FGK stars is the annular 2 kpc wide region that is centered at 8 kpc from the
Comparison of lead isotopes with source apportionment models, including SOM, for air particulates.
Gulson, Brian; Korsch, Michael; Dickson, Bruce; Cohen, David; Mizon, Karen; Davis, J Michael
2007-08-01
We have measured high precision lead isotopes in PM(2.5) particulates from a highly-trafficked site (Mascot) and rural site (Richmond) in the Sydney Basin, New South Wales, Australia to compare with isotopic data from total suspended particulates (TSP) from other sites in the Sydney Basin and evaluate relationships with source fingerprints obtained from multi-element PM(2.5) data. The isotopic data for the period 1998 to 2004 show seasonal peaks and troughs that are more pronounced in the rural site for the PM(2.5).samples but are consistent with the TSP. The Self Organising Map (SOM) method has been applied to the multi-element PM(2.5) data to evaluate its use in obtaining fingerprints for comparison with standard statistical procedures (ANSTO model). As seasonal effects are also significant for the multi-element data, the SOM modelling is reported as site and season dependent. At the Mascot site, the ANSTO model exhibits decreasing (206)Pb/(204)Pb ratios with increasing contributions of fingerprints for "secondary smoke" (industry), "soil", "smoke" and "seaspray". Similar patterns were shown by SOM winter fingerprints for both sites. At the rural site, there are large isotopic variations but for the majority of samples these are not associated with increased contributions from the main sources with the ANSTO model. For two winter sampling times, there are increased contributions from "secondary industry", "smoke", "soil" and seaspray with one time having a source or sources of Pb similar to that of Mascot. The only positive relationship between increasing (206)Pb/(204)Pb ratio and source contributions is found at the rural site using the SOM summer fingerprints, both of which show a significant contribution from sulphur. Several of the fingerprints using either model have significant contributions from black carbon (BC) and/or sulphur (S) that probably derive from diesel fuels and industrial sources. Increased contributions from sources with the SOM summer
Walzer, Amy S; Czopp, Alexander M
2011-01-01
The stereotype content model (SCM) posits that warmth and competence are the key components underlying judgments about social groups. Because competence can encompass different components (e.g., intelligence, talent) different group members may be perceived to be competent for different reasons. Therefore, we believe it may be important to specify the type of competence being assessed when examining perceptions of groups that are positively stereotyped (i.e., Black athletes and musical Blacks). Consistent with the SCM, these subgroups were perceived as high in competence-talent but not in competence-intelligence and low in warmth. Both the intelligence and talent frame of competence fit in the SCM's social structural hypothesis.
Microregion model of a contact line including evaporation, kinetics and slip
Anderson, Daniel; Janecek, Vladislav
2016-11-01
We consider the evaporation of a liquid on a uniformly heated solid substrate. In the framework of lubrication theory we consider hydrodynamics, heat conduction, phase change, evaporation kinetics, and slip. Our model focuses only on the contact line 'inner' region which allows us to quantify the impact of evaporation on the apparent contact angle and microregion heat transfer. The linearized problem with respect to the substrate overheating is solved analytically. The analytical solutions are compared with full numerical solutions and to predictions of Hocking.
DEFF Research Database (Denmark)
Andersen, Morten; Vinther, Frank; Ottesen, Johnny T.
2013-01-01
non-negative and bounded, which can be interpreted as a mathematical formulation of homeostasis. No oscillating solutions are present when using physiologically reasonable parameter values. This indicates that the ultradian rhythm originate from different mechanisms.Using physiologically reasonable......This paper presents a mathematical model of the HPA axis. The HPA axis consists of the hypothalamus, the pituitary and the adrenal glands in which the three hormones CRH, ACTH and cortisol interact through receptor dynamics. Furthermore, it has been suggested that receptors in the hippocampus have...
Energy Technology Data Exchange (ETDEWEB)
Avancini, S.S.; Marinelli, J.R. [Universidade Federal de Santa Catarina Florianopolis, Depto de Fisica - CFM, Florianopolis (Brazil); Carlson, B.V. [Instituto Tecnologico de Aeronautica, Sao Jose dos Campos (Brazil)
2013-06-15
Relativistic models for finite nuclei contain spurious center-of-mass motion in most applications for the nuclear many-body problem, where the nuclear wave function is taken as a single Slater determinant within a space-fixed frame description. We use the Peierls-Yoccoz projection method, previously developed for relativistic approaches together with a reparametrization of the coupling constants that fits binding energies and charge radius and apply our results to calculate elastic electron scattering monopole charge form factors for light nuclei. (orig.)
Double pendulum model for a tennis stroke including a collision process
Youn, Sun-Hyun
2015-10-01
By means of adding a collision process between the ball and racket in the double pendulum model, we analyzed the tennis stroke. The ball and the racket system may be accelerated during the collision time; thus, the speed of the rebound ball does not simply depend on the angular velocity of the racket. A higher angular velocity sometimes gives a lower rebound ball speed. We numerically showed that the proper time-lagged racket rotation increased the speed of the rebound ball by 20%. We also showed that the elbow should move in the proper direction in order to add the angular velocity of the racket.
Modeling the elastic behavior of ductile cast iron including anisotropy in the graphite nodules
DEFF Research Database (Denmark)
Andriollo, Tito; Thorborg, Jesper; Hattel, Jesper Henri
2016-01-01
This paper presents a micro-mechanical approach to model the intrinsic elastic anisotropy of the graphite particles in ductile iron. Contrary to most of the published works in the field, the constitutive behavior is directly derived on the basis of the nodule characteristic internal structure......, composed of graphite platelets arranged into conical sectors. In this way, the large uncertainty traditionally associated with local mechanical measurements of micro-hardness is eliminated. The proposed anisotropic description is validated by simulating the macroscopic ductile iron elastic response...
Including Antenna Models in Microwave Imaging for Breast-Cancer Screening
DEFF Research Database (Denmark)
Rubæk, Tonny; Meincke, Peter
2006-01-01
Microwave imaging is emerging as a tool for screening for breast cancer, but the lack of methods for including the characteristics of the antennas of the imaging systems in the imaging algorithms limits their performance. In this paper, a method for incorporating the full antenna characteristics......, in terms of the transmission-matrix representation, in a frequency-domain imaging algorithm is presented. The algorithm is tested on a simulation of the Physical-Anomaly Tomography (PAT) scanner imaging system developed at the Technical University of Denmark and is shown to have superior performance when...
The evolution of massive stars including mass loss - Presupernova models and explosion
Woosley, S. E.; Langer, Norbert; Weaver, Thomas A.
1993-01-01
The evolution of massive stars of 35, 40, 60, and 85 solar masses is followed through all stages of nuclear burning to the point of Fe core collapse. Critical nuclear reaction and mass-loss rates are varied. Efficient mass loss during the Wolf-Rayet (WR) stage is likely to lead to final masses as small as 4 solar masses. For a reasonable parameterization of the mass loss, there may be convergence of all WR stars, both single and in binaries, to a narrow band of small final masses. Our representative model, a 4.25 solar-mass WR presupernova derived from a 60 solar mass star, is followed through a simulated explosion, and its explosive nucleosynthesis and light curve are determined. Its properties are similar to those observed in Type Ib supernovae. The effects of the initial mass and mass loss on the presupernova structure of small mass WR models is also explored. Important properties of the presupernova star and its explosion can only be obtained by following the complete evolution starting on the main sequence.
Energy Technology Data Exchange (ETDEWEB)
Eichwald, C.; Kaiser, F. [Technical Univ. of Darmstadt (Germany)
1995-06-01
Experiments on the effects of extremely-low-frequency (ELF) electric and magnetic fields on cells of the immune system, T-lymphocytes in particular, suggest that the external field interacts with the cell at the level of intracellular signal transduction pathways. These are directly connected with changes in the calcium-signaling processes of the cell. Based on these findings, a theoretical model for receptor-controlled cytosolic calcium oscillations and for external influences on the signal transduction pathway is presented. The authors discuss the possibility that the external field acts on the kinetics of the signal transduction between the activated receptors at the cell membrane and the G-proteins. It is shown that, depending on the specific combination of cell internal biochemical and external physical parameters, entirely different responses of the cell can occur. The authors compare the effects of a coherent (periodic) modulation and of incoherent perturbations (noise). The model and the calculations are based on the theory of self-sustained, nonlinear oscillators. It is argued that these systems form an ideal basis for information-encoding processes in biological systems.
An Improved Heat Budget Estimation Including Bottom Effects for General Ocean Circulation Models
Carder, Kendall; Warrior, Hari; Otis, Daniel; Chen, R. F.
2001-01-01
This paper studies the effects of the underwater light field on heat-budget calculations of general ocean circulation models for shallow waters. The presence of a bottom significantly alters the estimated heat budget in shallow waters, which affects the corresponding thermal stratification and hence modifies the circulation. Based on the data collected during the COBOP field experiment near the Bahamas, we have used a one-dimensional turbulence closure model to show the influence of the bottom reflection and absorption on the sea surface temperature field. The water depth has an almost one-to-one correlation with the temperature rise. Effects of varying the bottom albedo by replacing the sea grass bed with a coral sand bottom, also has an appreciable effect on the heat budget of the shallow regions. We believe that the differences in the heat budget for the shallow areas will have an influence on the local circulation processes and especially on the evaporative and long-wave heat losses for these areas. The ultimate effects on humidity and cloudiness of the region are expected to be significant as well.
On the modelling of semi-insulating GaAs including surface tension and bulk stresses
Energy Technology Data Exchange (ETDEWEB)
Dreyer, W.; Duderstadt, F.
2004-07-01
Necessary heat treatment of single crystal semi-insulating Gallium Arsenide (GaAs), which is deployed in micro- and opto- electronic devices, generate undesirable liquid precipitates in the solid phase. The appearance of precipitates is influenced by surface tension at the liquid/solid interface and deviatoric stresses in the solid. The central quantity for the description of the various aspects of phase transitions is the chemical potential, which can be additively decomposed into a chemical and a mechanical part. In particular the calculation of the mechanical part of the chemical potential is of crucial importance. We determine the chemical potential in the framework of the St. Venant-Kirchhoff law which gives an appropriate stress/strain relation for many solids in the small strain regime. We establish criteria, which allow the correct replacement of the St. Venant-Kirchhoff law by the simpler Hooke law. The main objectives of this study are: (i) We develop a thermo-mechanical model that describes diffusion and interface motion, which both are strongly influenced by surface tension effects and deviatoric stresses. (ii) We give an overview and outlook on problems that can be posed and solved within the framework of the model. (iii) We calculate non-standard phase diagrams, i.e. those that take into account surface tension and non-deviatoric stresses, for GaAs above 786 C, and we compare the results with classical phase diagrams without these phenomena. (orig.)
Grids of stellar models including second harmonic and colours: Solar composition
Yildiz, Mutlu
2015-01-01
Grids of stellar evolution are required in many fields of astronomy/astrophysics, such as planet hosting stars, binaries, clusters, chemically peculiar stars, etc. In this study, a grid of stellar evolution models with updated ingredients and {recently determined solar abundaces} is presented. The solar values for the initial abundances of hydrogen, heavy elements and mixing-length parameter are 0.0172, 0.7024 and 1.98, respectively. The mass step is small enough (0.01 M$_\\odot$) that interpolation for a given star mass is not required. The range of stellar mass is 0.74 to 10.00 M$_\\odot$. We present results in different forms of tables for easy and general application. The second stellar harmonic, required for analysis of apsidal motion of eclipsing binaries, is also listed. We also construct rotating models to determine effect of rotation on stellar structure and derive fitting formula for luminosity, radius and the second stellar harmonic as a function of rotational parameter. We also compute and list colo...
Analysis of the R-symmetric supersymmetric models including quantum corrections
Kotlarski, Wojciech
2016-01-01
We study the Minimal R-symmetric Supersymmetric Standard Model (MRSSM) at the quantum level. The thesis consists of two parts. First one treats about the electroweak sector of the model. Among others, it identifies the parameter region allowed by the electroweak precision observables. Since the MRSSM contains an $SU(2)_L$-triplet with a non-zero vacuum expectation value the emphasis is put on the calculation of the $W$ boson mass. To that end, a full one-loop calculation of $m_W$ augmented with the leading two-loop SM result is presented. The region is then checked against the measurement of the Higgs boson mass. For this, the full one-loop and leading two-loop corrections to the Higgs boson mass in the MRSSM are calculated. Devised benchmark points, consistent with both of these observables, are shown to fulfill also a number of additional experimental constraints like properties of the Higgs boson(s), $b$-physics observables and vacuum stability. Correlating all of these observables allows to put bounds on ...
Description and Application of A Model of Seepage under A Weir Including Mechanical Clogging
Directory of Open Access Journals (Sweden)
Sroka Zbigniew
2014-07-01
Full Text Available The paper discusses seepage flow under a damming structure (a weir in view of mechanical clogging in a thin layer at the upstream site. It was assumed that in this layer flow may be treated as one-dimensional (perpendicular to the layer, while elsewhere flow was modelled as two-dimensional. The solution in both zones was obtained in the discrete form using the finite element method and the Euler method. The effect of the clogging layer on seepage flow was modelled using the third kind boundary condition. Seepage parameters in the clogging layer were estimated based on laboratory tests conducted by Skolasińska [2006]. Typical problem was taken to provide simulation and indicate how clogging affects the seepage rate and other parameters of the flow. Results showed that clogging at the upstream site has a significant effect on the distribution of seepage velocity and hydraulic gradients. The flow underneath the structure decreases with time, but these changes are relatively slow.
Fritz, Thomas; Wieners, Christian; Seemann, Gunnar; Steen, Henning; Dössel, Olaf
2014-06-01
During the contraction of the ventricles, the ventricles interact with the atria as well as with the pericardium and the surrounding tissue in which the heart is embedded. The atria are stretched, and the atrioventricular plane moves toward the apex. The atrioventricular plane displacement (AVPD) is considered to be a major contributor to the ventricular function, and a reduced AVPD is strongly related to heart failure. At the same time, the epicardium slides almost frictionlessly on the pericardium with permanent contact. Although the interaction between the ventricles, the atria and the pericardium plays an important role for the deformation of the heart, this aspect is usually not considered in computational models. In this work, we present an electromechanical model of the heart, which takes into account the interaction between ventricles, pericardium and atria and allows to reproduce the AVPD. To solve the contact problem of epicardium and pericardium, a contact handling algorithm based on penalty formulation was developed, which ensures frictionless and permanent contact. Two simulations of the ventricular contraction were conducted, one with contact handling of pericardium and heart and one without. In the simulation with contact handling, the atria were stretched during the contraction of the ventricles, while, due to the permanent contact with the pericardium, their volume increased. In contrast to that, in the simulations without pericardium, the atria were also stretched, but the change in the atrial volume was much smaller. Furthermore, the pericardium reduced the radial contraction of the ventricles and at the same time increased the AVPD.
Sacchi, Mattia; Balleza, Daniel; Vena, Giulia; Puia, Giulia; Facci, Paolo; Alessandrini, Andrea
2015-05-01
Amphiphilic molecules which have a biological effect on specific membrane proteins, could also affect lipid bilayer properties possibly resulting in a modulation of the overall membrane behavior. In light of this consideration, it is important to study the possible effects of amphiphilic molecule of pharmacological interest on model systems which recapitulate some of the main properties of the biological plasma membranes. In this work we studied the effect of a neurosteroid, Allopregnanolone (3α,5α-tetrahydroprogesterone or Allo), on a model bilayer composed by the ternary lipid mixture DOPC/bSM/chol. We chose ternary mixtures which present, at room temperature, a phase coexistence of liquid ordered (Lo) and liquid disordered (Ld) domains and which reside near to a critical point. We found that Allo, which is able to strongly partition in the lipid bilayer, induces a marked increase in the bilayer area and modifies the relative proportion of the two phases favoring the Ld phase. We also found that the neurosteroid shifts the miscibility temperature to higher values in a way similarly to what happens when the cholesterol concentration is decreased. Interestingly, an isoform of Allo, isoAllopregnanolone (3β,5α-tetrahydroprogesterone or isoAllo), known to inhibit the effects of Allo on GABAA receptors, has an opposite effect on the bilayer properties.
Energy Technology Data Exchange (ETDEWEB)
Mansoori, Zohreh; Saffar-Avval, Majid; Basirat-Tabrizi, Hassan; Ahmadi, Goodarz; Lain, Santiago
2002-12-01
A thermo-mechanical turbulence model is developed and used for predicting heat transfer in a gas-solid flow through a vertical pipe with constant wall heat flux. The new four-way interaction model makes use of the thermal k{sub {theta}}-{tau}{sub {theta}} equations, in addition to the hydrodynamic k-{tau} transport, and accounts for the particle-particle and particle-wall collisions through a Eulerian/Lagrangian formulation. The simulation results indicate that the level of thermal turbulence intensity and the heat transfer are strongly affected by the particle collisions. Inter-particle collisions attenuate the thermal turbulence intensity near the wall but somewhat amplify the temperature fluctuations in the pipe core region. The hydrodynamic-to-thermal times-scale ratio and the turbulent Prandtl number in the region near the wall increase due to the inter-particle collisions. The results also show that the use of a constant or the single-phase gas turbulent Prandtl number produces error in the thermal eddy diffusivity and thermal turbulent intensity fields. Simulation results also indicate that the inter-particle contact heat conduction during collision has no significant effect in the range of Reynolds number and particle diameter studied.
The evolution of massive stars including mass loss - Presupernova models and explosion
Woosley, S. E.; Langer, Norbert; Weaver, Thomas A.
1993-01-01
The evolution of massive stars of 35, 40, 60, and 85 solar masses is followed through all stages of nuclear burning to the point of Fe core collapse. Critical nuclear reaction and mass-loss rates are varied. Efficient mass loss during the Wolf-Rayet (WR) stage is likely to lead to final masses as small as 4 solar masses. For a reasonable parameterization of the mass loss, there may be convergence of all WR stars, both single and in binaries, to a narrow band of small final masses. Our representative model, a 4.25 solar-mass WR presupernova derived from a 60 solar mass star, is followed through a simulated explosion, and its explosive nucleosynthesis and light curve are determined. Its properties are similar to those observed in Type Ib supernovae. The effects of the initial mass and mass loss on the presupernova structure of small mass WR models is also explored. Important properties of the presupernova star and its explosion can only be obtained by following the complete evolution starting on the main sequence.
Usmanov, Arcadi V.; Goldstein, Melvyn L.; Matthaeus, William H.
2012-01-01
To study the effects of interstellar pickup protons and turbulence on the structure and dynamics of the solar wind, we have developed a fully three-dimensional magnetohydrodynamic solar wind model that treats interstellar pickup protons as a separate fluid and incorporates the transport of turbulence and turbulent heating. The governing system of equations combines the mean-field equations for the solar wind plasma, magnetic field, and pickup protons and the turbulence transport equations for the turbulent energy, normalized cross-helicity, and correlation length. The model equations account for photoionization of interstellar hydrogen atoms and their charge exchange with solar wind protons, energy transfer from pickup protons to solar wind protons, and plasma heating by turbulent dissipation. Separate mass and energy equations are used for the solar wind and pickup protons, though a single momentum equation is employed under the assumption that the pickup protons are comoving with the solar wind protons.We compute the global structure of the solar wind plasma, magnetic field, and turbulence in the region from 0.3 to 100 AU for a source magnetic dipole on the Sun tilted by 0 deg - .90 deg and compare our results with Voyager 2 observations. The results computed with and without pickup protons are superposed to evaluate quantitatively the deceleration and heating effects of pickup protons, the overall compression of the magnetic field in the outer heliosphere caused by deceleration, and the weakening of corotating interaction regions by the thermal pressure of pickup protons.
Perceptual-center modeling is affected by including acoustic rate-of-change modulations.
Harsin, C A
1997-02-01
This study investigated the acoustic correlates of perceptual centers (p-centers) in CV and VC syllables and developed an acoustic p-center model. In Part 1, listeners located syllables' p-centers by a method-of-adjustment procedure. The CV syllables contained the consonants /s/,/r/,/n/,/t/,/d/,/k/, and /g/; the VCs, the consonants /s/,/r/, and /n/. The vowel in all syllables was /a/. The results of this experiment replicated and extended previous findings regarding the effects of phonetic variation on p-centers. In Part 2, a digital signal processing procedure was used to acoustically model p-center perception. Each stimulus was passed through a six-band digital filter, and the outputs were processed to derive low-frequency modulation components. These components were weighted according to a perceived modulation magnitude function and recombined to create six psychoacoustic envelopes containing modulation energies from 3 to 47 Hz. In this analysis, p-centers were found to be highly correlated with the time-weighted function of the rate-of-change in the psychoacoustic envelopes, multiplied by the psychoacoustic envelope magnitude increment. The results were interpreted as suggesting (1) the probable role of low-frequency energy modulations in p-center perception, and (2) the presence of perceptual processes that integrate multiple articulatory events into a single syllabic event.
Dai, Wangde; Kloner, Robert A
2010-01-01
As a novel potential therapeutic strategy for cardiac disease, cell transplantation therapy has been extensively investigated in experimental studies and clinical trials. Although encouraging results have been demonstrated, a number of critical questions still remain to be answered. For example, what kind of stem cell and how many cells should be used; what is the best time for cell transplantation after acute myocardial infarction; which delivery approach is better, intravenous injection or direct intramyocardial injection? Transplantation of cells derived from human tissues into experimental animals may elicit an immune rejection. Immunodeficient nude rats provide a useful myocardial infarction model for cell transplantation therapy studies. We introduce our detailed methods of direct intramyocardial injection of immature heart cells and stem cells into the myocardial infarction region of rats and nude rats. Careful maintenance under aseptic conditions and proper surgical technique are essential to improve the survival of immunodeficient rats after surgery.
Including ethical considerations in models for ﬁrst-trimester screening for pre-eclampsia
DEFF Research Database (Denmark)
Jørgensen, Jennifer Maureen; Hedley, Paula L.; Gjerris, Mickey;
2014-01-01
Recent efforts to develop reliable and efficient early pregnancy screening programmes for pre-eclampsia have focused on com-bining clinical, biochemical and biophysical markers. The same model has been used for first-trimester screening for fetal aneuploidies i.e. prenatal diagnosis (PD), which...... is routinely offered to all pregnant women in many developed countries. Some studies suggest combining PD and pre-eclampsia screening, so women can be offered testing for a number of conditions at the same clinical visit. A combination of these tests may be practical in terms of saving time and resources......; however, the combination raises ethical issues. First-trimester PD and pre-eclampsia screening entail qualitative differences which alter the requirements for disclosure, non-directedness and consent with regard to the informed consent process. This article explores the differences related to the ethical...
Memory of the Vernalized State in Plants including the Model Grass Brachypodium distachyon
Directory of Open Access Journals (Sweden)
Daniel P Woods
2014-03-01
Full Text Available Plant species that have a vernalization requirement exhibit variation in the ability to remember winter—i.e., variation in the stability of the vernalized state. Studies in Arabidopsis have demonstrated that molecular memory involves changes in the chromatin state and expression of the flowering repressor FLOWERING LOCUS C, and have revealed that single-gene differences can have large effects on the stability of the vernalized state. In the perennial Arabidopsis relative Arabis alpina, the lack of memory of winter is critical for its perennial life history. Our studies of flowering behavior in the model grass Brachypodium distachyon reveal extensive variation in the vernalization requirement, and studies of a particular Brachypodium accession that has a qualitative requirement for both cold exposure and inductive daylength reveals that Brachypodium can exhibit a highly stable vernalized state.
The economic production lot size model extended to include more than one production rate
DEFF Research Database (Denmark)
Larsen, Christian
2001-01-01
btween the demand rate and the production rate which minimizes unit production costs, and should be used in an increasing order. Then, given the production rates, we derive closed-form expressions for all optimal runtimes as well as the minimum average cost. This analysis reveals that it is the size......We study an extension of the economic production lot size model, where more than one production rate can be used during a cycle. Moreover, the production rates, as well as their corresponding runtimes are decision variables. First, we show that all production rates should be choosen in the interval...... of the setup cost that determines the need for being able to use several production rates. Finally, we show how to derive a near-optimal solution of the general problem....
The economic production lot size model extended to include more than one production rate
DEFF Research Database (Denmark)
Larsen, Christian
2005-01-01
production rates should be chosen in the interval between the demand rate and the production rate which minimizes unit production costs, and should be used in an increasing order. Then, given the production rates, we derive closed-form expressions for all optimal runtimes as well as the minimum average cost......We study an extension of the economic production lot size model, where more than one production rate can be used during a cycle. Moreover, the production rates, as well as their corresponding runtimes are decision variables. We decompose the problem into two subproblems. First, we show that all....... This analysis reveals that it is the size of the setup cost that determines the need for being able to use several production rates. We also show how to derive a near-optimal solution of the general problem....
Modelling of safety barriers including human and organisational factors to improve process safety
DEFF Research Database (Denmark)
Markert, Frank; Duijm, Nijs Jan; Thommesen, Jacob
2013-01-01
explosion, and the Mont Blanc Tunnel Fire, such an approach may have helped to maintain the integrity of the designed provisions against major deviations resulting in these disasters. In order to make this paradigm operational, safety management and in particular risk assessment tools need to be refined....... A valuable approach is the inclusion of human and organisational factors into the simulation of the reliability of the technical system using event trees and fault trees and the concept of safety barriers. This has been demonstrated e.g. in the former European research project ARAMIS (Accidental Risk...... Assessment Methodology for IndustrieS, see Salvi et al 2006). ARAMIS employs the bow-tie approach to modelling hazardous scenarios, and it suggests the outcome of auditing safety management to be connected to a semi-quantitative assessment of the quality of safety barriers. ARAMIS discriminates a number...
Non-insect crustacean models in developmental genetics including an encomium to Parhyale hawaiensis.
Stamataki, Evangelia; Pavlopoulos, Anastasios
2016-08-01
The impressive diversity of body plans, lifestyles and segmental specializations exhibited by crustaceans (barnacles, copepods, shrimps, crabs, lobsters and their kin) provides great material to address longstanding questions in evolutionary developmental biology. Recent advances in forward and reverse genetics and in imaging approaches applied in the amphipod Parhyale hawaiensis and other emerging crustacean model species have made it possible to probe the molecular and cellular basis of crustacean diversity. A number of biological and technical qualities like the slow tempo and holoblastic cleavage mode, the stereotypy of many cellular processes, the functional and morphological diversity of limbs along the body axis, and the availability of various experimental manipulations, have made Parhyale a powerful system to study normal development and regeneration. Copyright © 2016 Elsevier Ltd. All rights reserved.
Directory of Open Access Journals (Sweden)
Isabelle Bloch
2007-01-01
Full Text Available This paper describes a system for optical music recognition (OMR in case of monophonic typeset scores. After clarifying the difficulties specific to this domain, we propose appropriate solutions at both image analysis level and high-level interpretation. Thus, a recognition and segmentation method is designed, that allows dealing with common printing defects and numerous symbol interconnections. Then, musical rules are modeled and integrated, in order to make a consistent decision. This high-level interpretation step relies on the fuzzy sets and possibility framework, since it allows dealing with symbol variability, flexibility, and imprecision of music rules, and merging all these heterogeneous pieces of information. Other innovative features are the indication of potential errors and the possibility of applying learning procedures, in order to gain in robustness. Experiments conducted on a large data base show that the proposed method constitutes an interesting contribution to OMR.
Rossant, Florence; Bloch, Isabelle
2006-12-01
This paper describes a system for optical music recognition (OMR) in case of monophonic typeset scores. After clarifying the difficulties specific to this domain, we propose appropriate solutions at both image analysis level and high-level interpretation. Thus, a recognition and segmentation method is designed, that allows dealing with common printing defects and numerous symbol interconnections. Then, musical rules are modeled and integrated, in order to make a consistent decision. This high-level interpretation step relies on the fuzzy sets and possibility framework, since it allows dealing with symbol variability, flexibility, and imprecision of music rules, and merging all these heterogeneous pieces of information. Other innovative features are the indication of potential errors and the possibility of applying learning procedures, in order to gain in robustness. Experiments conducted on a large data base show that the proposed method constitutes an interesting contribution to OMR.
Parsing recursive sentences with a connectionist model including a neural stack and synaptic gating.
Fedor, Anna; Ittzés, Péter; Szathmáry, Eörs
2011-02-21
It is supposed that humans are genetically predisposed to be able to recognize sequences of context-free grammars with centre-embedded recursion while other primates are restricted to the recognition of finite state grammars with tail-recursion. Our aim was to construct a minimalist neural network that is able to parse artificial sentences of both grammars in an efficient way without using the biologically unrealistic backpropagation algorithm. The core of this network is a neural stack-like memory where the push and pop operations are regulated by synaptic gating on the connections between the layers of the stack. The network correctly categorizes novel sentences of both grammars after training. We suggest that the introduction of the neural stack memory will turn out to be substantial for any biological 'hierarchical processor' and the minimalist design of the model suggests a quest for similar, realistic neural architectures.
Areal rainfall estimation using moving cars - computer experiments including hydrological modeling
Rabiei, Ehsan; Haberlandt, Uwe; Sester, Monika; Fitzner, Daniel; Wallner, Markus
2016-09-01
The need for high temporal and spatial resolution precipitation data for hydrological analyses has been discussed in several studies. Although rain gauges provide valuable information, a very dense rain gauge network is costly. As a result, several new ideas have emerged to help estimating areal rainfall with higher temporal and spatial resolution. Rabiei et al. (2013) observed that moving cars, called RainCars (RCs), can potentially be a new source of data for measuring rain rate. The optical sensors used in that study are designed for operating the windscreen wipers and showed promising results for rainfall measurement purposes. Their measurement accuracy has been quantified in laboratory experiments. Considering explicitly those errors, the main objective of this study is to investigate the benefit of using RCs for estimating areal rainfall. For that, computer experiments are carried out, where radar rainfall is considered as the reference and the other sources of data, i.e., RCs and rain gauges, are extracted from radar data. Comparing the quality of areal rainfall estimation by RCs with rain gauges and reference data helps to investigate the benefit of the RCs. The value of this additional source of data is not only assessed for areal rainfall estimation performance but also for use in hydrological modeling. Considering measurement errors derived from laboratory experiments, the result shows that the RCs provide useful additional information for areal rainfall estimation as well as for hydrological modeling. Moreover, by testing larger uncertainties for RCs, they observed to be useful up to a certain level for areal rainfall estimation and discharge simulation.
ECO: a generic eutrophication model including comprehensive sediment-water interaction.
Directory of Open Access Journals (Sweden)
Johannes G C Smits
Full Text Available The content and calibration of the comprehensive generic 3D eutrophication model ECO for water and sediment quality is presented. Based on a computational grid for water and sediment, ECO is used as a tool for water quality management to simulate concentrations and mass fluxes of nutrients (N, P, Si, phytoplankton species, detrital organic matter, electron acceptors and related substances. ECO combines integral simulation of water and sediment quality with sediment diagenesis and closed mass balances. Its advanced process formulations for substances in the water column and the bed sediment were developed to allow for a much more dynamic calculation of the sediment-water exchange fluxes of nutrients as resulting from steep concentration gradients across the sediment-water interface than is possible with other eutrophication models. ECO is to more accurately calculate the accumulation of organic matter and nutrients in the sediment, and to allow for more accurate prediction of phytoplankton biomass and water quality in response to mitigative measures such as nutrient load reduction. ECO was calibrated for shallow Lake Veluwe (The Netherlands. Due to restoration measures this lake underwent a transition from hypertrophic conditions to moderately eutrophic conditions, leading to the extensive colonization by submerged macrophytes. ECO reproduces observed water quality well for the transition period of ten years. The values of its process coefficients are in line with ranges derived from literature. ECO's calculation results underline the importance of redox processes and phosphate speciation for the nutrient return fluxes. Among other things, the results suggest that authigenic formation of a stable apatite-like mineral in the sediment can contribute significantly to oligotrophication of a lake after a phosphorus load reduction.
Directory of Open Access Journals (Sweden)
P. Kumar
2009-04-01
Full Text Available Dust and black carbon aerosol have long been known to exert potentially important and diverse impacts on cloud droplet formation. Most studies to date focus on the soluble fraction of these particles, and overlook interactions of the insoluble fraction with water vapor (even if known to be hydrophilic. To address this gap, we developed a new parameterization that considers cloud droplet formation within an ascending air parcel containing insoluble (but wettable particles externally mixed with aerosol containing an appreciable soluble fraction. Activation of particles with a soluble fraction is described through well-established Köhler theory, while the activation of hydrophilic insoluble particles is treated by "adsorption-activation" theory. In the latter, water vapor is adsorbed onto insoluble particles, the activity of which is described by a multilayer Frenkel-Halsey-Hill (FHH adsorption isotherm modified to account for particle curvature. We further develop FHH activation theory to i find combinations of the adsorption parameters A_{FHH}, B_{FHH} which yield atmospherically-relevant behavior, and, ii express activation properties (critical supersaturation that follow a simple power law with respect to dry particle diameter.
The new parameterization is tested by comparing the parameterized cloud droplet number concentration against predictions with a detailed numerical cloud model, considering a wide range of particle populations, cloud updraft conditions, water vapor condensation coefficient and FHH adsorption isotherm characteristics. The agreement between parameterization and parcel model is excellent, with an average error of 10% and R^{2}~0.98. A preliminary sensitivity study suggests that the sublinear response of droplet number to Köhler particle concentration is not as strong for FHH particles.
Kumar, P.; Sokolik, I. N.; Nenes, A.
2009-04-01
Dust and black carbon aerosol have long been known to exert potentially important and diverse impacts on cloud droplet formation. Most studies to date focus on the soluble fraction of these particles, and overlook interactions of the insoluble fraction with water vapor (even if known to be hydrophilic). To address this gap, we developed a new parameterization that considers cloud droplet formation within an ascending air parcel containing insoluble (but wettable) particles externally mixed with aerosol containing an appreciable soluble fraction. Activation of particles with a soluble fraction is described through well-established Köhler theory, while the activation of hydrophilic insoluble particles is treated by "adsorption-activation" theory. In the latter, water vapor is adsorbed onto insoluble particles, the activity of which is described by a multilayer Frenkel-Halsey-Hill (FHH) adsorption isotherm modified to account for particle curvature. We further develop FHH activation theory to i) find combinations of the adsorption parameters AFHH, BFHH which yield atmospherically-relevant behavior, and, ii) express activation properties (critical supersaturation) that follow a simple power law with respect to dry particle diameter. The new parameterization is tested by comparing the parameterized cloud droplet number concentration against predictions with a detailed numerical cloud model, considering a wide range of particle populations, cloud updraft conditions, water vapor condensation coefficient and FHH adsorption isotherm characteristics. The agreement between parameterization and parcel model is excellent, with an average error of 10% and R2~0.98. A preliminary sensitivity study suggests that the sublinear response of droplet number to Köhler particle concentration is not as strong for FHH particles.
ECO: a generic eutrophication model including comprehensive sediment-water interaction.
Smits, Johannes G C; van Beek, Jan K L
2013-01-01
The content and calibration of the comprehensive generic 3D eutrophication model ECO for water and sediment quality is presented. Based on a computational grid for water and sediment, ECO is used as a tool for water quality management to simulate concentrations and mass fluxes of nutrients (N, P, Si), phytoplankton species, detrital organic matter, electron acceptors and related substances. ECO combines integral simulation of water and sediment quality with sediment diagenesis and closed mass balances. Its advanced process formulations for substances in the water column and the bed sediment were developed to allow for a much more dynamic calculation of the sediment-water exchange fluxes of nutrients as resulting from steep concentration gradients across the sediment-water interface than is possible with other eutrophication models. ECO is to more accurately calculate the accumulation of organic matter and nutrients in the sediment, and to allow for more accurate prediction of phytoplankton biomass and water quality in response to mitigative measures such as nutrient load reduction. ECO was calibrated for shallow Lake Veluwe (The Netherlands). Due to restoration measures this lake underwent a transition from hypertrophic conditions to moderately eutrophic conditions, leading to the extensive colonization by submerged macrophytes. ECO reproduces observed water quality well for the transition period of ten years. The values of its process coefficients are in line with ranges derived from literature. ECO's calculation results underline the importance of redox processes and phosphate speciation for the nutrient return fluxes. Among other things, the results suggest that authigenic formation of a stable apatite-like mineral in the sediment can contribute significantly to oligotrophication of a lake after a phosphorus load reduction.
Folk, R; Holovatch, Yu; Moser, G
2009-03-01
We calculate the relaxational dynamical critical behavior of systems of O(n_{ parallel}) plus sign in circleO(n_{ perpendicular}) symmetry including conservation of magnetization by renormalization group theory within the minimal subtraction scheme in two-loop order. Within the stability region of the Heisenberg fixed point and the biconical fixed point, strong dynamical scaling holds, with the asymptotic dynamical critical exponent z=2varphinu-1 , where varphi is the crossover exponent and nu the exponent of the correlation length. The critical dynamics at n_{ parallel}=1 and n_{ perpendicular}=2 is governed by a small dynamical transient exponent leading to nonuniversal nonasymptotic dynamical behavior. This may be seen, e.g., in the temperature dependence of the magnetic transport coefficients.
Energy Technology Data Exchange (ETDEWEB)
Paeth, H. [Geographical Institute, University of Wuerzburg, Am Hubland, 97074 Wuerzburg (Germany); Thamm, H.P. [Geographical Institute, University of Bonn, Bonn (Germany)
2007-08-15
Previous studies have highlighted the crucial role of land degradation in tropical African climate. This effect urgently has to be taken into account when predicting future African climate under enhanced greenhouse conditions. Here, we present time slice experiments of African climate until 2025, using a high-resolution regional climate model. A supposable scenario of future land use changes, involving vegetation loss and soil degradation, is prescribed simultaneously with increasing greenhouse-gas concentrations in order to detect, where the different forcings counterbalance or reinforce each other. This proceeding allows us to define the regions of highest vulnerability with respect to future freshwater availability and food security in tropical and subtropical Africa and may provide a decision basis for political measures. The model simulates a considerable reduction in precipitation amount until 2025 over most of tropical Africa, amounting to partly more than 500 mm (20-40% of the annual sum), particularly in the Congo Basin and the Sahel Zone. The change is strongest in boreal summer and basically reflects the pattern of maximum vegetation cover during the seasonal cycle. The related change in the surface energy fluxes induces a substantial near-surface warming by up to 7C. According to the modified temperature gradients over tropical Africa, the summer monsoon circulation intensifies and transports more humid air masses into the southern part of West Africa. This humidifying effect is overcompensated by a remarkable decrease in surface evaporation, leading to the overall drying tendency over most of Africa. Extreme daily rainfall events become stronger in autumn but less intense in spring. Summer and autumn appear to be characterized by more severe heat waves over Subsaharan West Africa. In addition, the Tropical Easterly Jet is weakening, leading to enhanced drought conditions in the Sahel Zone. All these results suggest that the local impact of land
Nuclear Reactor/Hydrogen Process Interface Including the HyPEP Model
Energy Technology Data Exchange (ETDEWEB)
Steven R. Sherman
2007-05-01
The Nuclear Reactor/Hydrogen Plant interface is the intermediate heat transport loop that will connect a very high temperature gas-cooled nuclear reactor (VHTR) to a thermochemical, high-temperature electrolysis, or hybrid hydrogen production plant. A prototype plant called the Next Generation Nuclear Plant (NGNP) is planned for construction and operation at the Idaho National Laboratory in the 2018-2021 timeframe, and will involve a VHTR, a high-temperature interface, and a hydrogen production plant. The interface is responsible for transporting high-temperature thermal energy from the nuclear reactor to the hydrogen production plant while protecting the nuclear plant from operational disturbances at the hydrogen plant. Development of the interface is occurring under the DOE Nuclear Hydrogen Initiative (NHI) and involves the study, design, and development of high-temperature heat exchangers, heat transport systems, materials, safety, and integrated system models. Research and development work on the system interface began in 2004 and is expected to continue at least until the start of construction of an engineering-scale demonstration plant.
Landau quantized dynamics and spectra for group-VI dichalcogenides, including a model quantum wire
Directory of Open Access Journals (Sweden)
Norman J. M. Horing
2017-06-01
Full Text Available This work is concerned with the derivation of the Green’s function for Landau-quantized carriers in the Group-VI dichalcogenides. In the spatially homogeneous case, the Green’s function is separated into a Peierls phase factor and a translationally invariant part which is determined in a closed form integral representation involving only elementary functions. The latter is expanded in an eigenfunction series of Laguerre polynomials. These results for the retarded Green’s function are presented in both position and momentum representations, and yet another closed form representation is derived in circular coordinates in terms of the Bessel wave function of the second kind (not to be confused with the Bessel function. The case of a quantum wire is also addressed, representing the quantum wire in terms of a model one-dimensional δ(x-potential profile. This retarded Green’s function for propagation directly along the wire is determined exactly in terms of the corresponding Green’s function for the system without the δ(x-potential, and the Landau quantized eigenenergy dispersion relation is examined. The thermodynamic Green’s function for the dichalcogenide carriers in a normal magnetic field is formulated here in terms of its spectral weight, and its solution is presented in a momentum/integral representation involving only elementary functions, which is subsequently expanded in Laguerre eigenfunctions and presented in both momentum and position representations.
A fully model-based MPC solution including VSB shot dose assignment and shape correction
Bork, Ingo; Buck, Peter; Reddy, Murali; Durvasula, Bhardwaj
2015-10-01
The value of using multiple dose levels for individual shots on VSB (Variable Shaped Beam) mask writers has been demonstrated earlier [1][2]. The main advantage of modulating dose on a per shot basis is the fact that higher dose levels can be used selectively for critical features while other areas of the mask with non-critical feature types can be exposed at lower dose levels. This reduces the amount of backscattering and mask write time penalty compared to a global overdose-undersize approach. While dose assignment to certain polygons or parts of polygons (VSB shots) can easily be accomplished via DRC rules on layers with limited shape variations like contact or VIA layers, it can be challenging to come up with consistent rules for layers consisting of a very broad range of shapes, generally found on metal layers. This work introduces a method for fully model-based modulation of shot dose for VSB machines supporting between two and eight dose levels and demonstrates results achieved with this method.
Pilgrim, Matthew G.; Lengyel, Imre; Lanzirotti, Antonio; Newville, Matt; Fearn, Sarah; Emri, Eszter; Knowles, Jonathan C.; Messinger, Jeffrey D.; Read, Russell W.; Guidry, Clyde; Curcio, Christine A.
2017-01-01
Purpose Extracellular deposits containing hydroxyapatite, lipids, proteins, and trace metals that form between the basal lamina of the RPE and the inner collagenous layer of Bruch's membrane are hallmarks of early AMD. We examined whether cultured RPE cells could produce extracellular deposits containing all of these molecular components. Methods Retinal pigment epithelium cells isolated from freshly enucleated porcine eyes were cultured on Transwell membranes for up to 6 months. Deposit composition and structure were characterized using light, fluorescence, and electron microscopy; synchrotron x-ray diffraction and x-ray fluorescence; secondary ion mass spectroscopy; and immunohistochemistry. Results Apparently functional primary RPE cells, when cultured on 10-μm-thick inserts with 0.4-μm-diameter pores, can produce sub-RPE deposits that contain hydroxyapatite, lipids, proteins, and trace elements, without outer segment supplementation, by 12 weeks. Conclusions The data suggest that sub-RPE deposit formation is initiated, and probably regulated, by the RPE, as well as the loss of permeability of the Bruch's membrane and choriocapillaris complex associated with age and early AMD. This cell culture model of early AMD lesions provides a novel system for testing new therapeutic interventions against sub-RPE deposit formation, an event occurring well in advance of the onset of vision loss. PMID:28146236
Landau quantized dynamics and spectra for group-VI dichalcogenides, including a model quantum wire
Horing, Norman J. M.
2017-06-01
This work is concerned with the derivation of the Green's function for Landau-quantized carriers in the Group-VI dichalcogenides. In the spatially homogeneous case, the Green's function is separated into a Peierls phase factor and a translationally invariant part which is determined in a closed form integral representation involving only elementary functions. The latter is expanded in an eigenfunction series of Laguerre polynomials. These results for the retarded Green's function are presented in both position and momentum representations, and yet another closed form representation is derived in circular coordinates in terms of the Bessel wave function of the second kind (not to be confused with the Bessel function). The case of a quantum wire is also addressed, representing the quantum wire in terms of a model one-dimensional δ (x ) -potential profile. This retarded Green's function for propagation directly along the wire is determined exactly in terms of the corresponding Green's function for the system without the δ (x ) -potential, and the Landau quantized eigenenergy dispersion relation is examined. The thermodynamic Green's function for the dichalcogenide carriers in a normal magnetic field is formulated here in terms of its spectral weight, and its solution is presented in a momentum/integral representation involving only elementary functions, which is subsequently expanded in Laguerre eigenfunctions and presented in both momentum and position representations.
Directory of Open Access Journals (Sweden)
Niko Schäpke
2014-07-01
Full Text Available Sustainability transitions require altered individual behaviors. Policies aimed at changing people’s consumption behavior are designed according to efficiency, consistency, and sufficiency principles. Taking into account shortcomings of the first two principles, this paper specifically addresses the sufficiency principle. Sufficiency policies are not very popular due to the fear that they may impede quality of life. This fear might be eased when highlighting the motivational side of sustainable behavior, such as the wish to care for future generations and the world’s poor. This article uses the capability approach (CA, developed primarily by Nobel-laureate economist Amartya Sen (1987a and philosopher Martha Nussbaum (1993, 2000, to a include the differentiation between self- and other-oriented goals and behavior, b build on its demonstrated success in assessing quality of life, and c assess the sustainability of behavior and policies. These three facets make CA suitable to analyze the effectiveness of sufficiency policies on sustainability and quality of life. To better understand the motivational side of sustainable behavior, CA is here for the first time enriched through approaches from environmental psychology. This enables us to highlight the idea of intrinsic empowerment as a building block for sufficiency policies. We close the article by highlighting further avenues for research.
Moyer, R. A.; Paz-Soldan, C.; Nazikian, R.; Orlov, D. M.; Ferraro, N. M.; Grierson, B. A.; Knölker, M.; Lyons, B. C.; McKee, G. R.; Osborne, T. H.; Rhodes, T. L.; Meneghini, O.; Smith, S.; Evans, T. E.; Fenstermacher, M. E.; Groebner, R. J.; Hanson, J. M.; La Haye, R. J.; Luce, T. C.; Mordijck, S.; Solomon, W. M.; Turco, F.; Yan, Z.; Zeng, L.; DIII-D Team
2017-10-01
Experiments have been executed in the DIII-D tokamak to extend suppression of Edge Localized Modes (ELMs) with Resonant Magnetic Perturbations (RMPs) to ITER-relevant levels of beam torque. The results support the hypothesis for RMP ELM suppression based on transition from an ideal screened response to a tearing response at a resonant surface that prevents expansion of the pedestal to an unstable width [Snyder et al., Nucl. Fusion 51, 103016 (2011) and Wade et al., Nucl. Fusion 55, 023002 (2015)]. In ITER baseline plasmas with I/aB = 1.4 and pedestal ν* ˜ 0.15, ELMs are readily suppressed with co- Ip neutral beam injection. However, reducing the beam torque from 5 Nm to ≤ 3.5 Nm results in loss of ELM suppression and a shift in the zero-crossing of the electron perpendicular rotation ω⊥e ˜ 0 deeper into the plasma. The change in radius of ω⊥e ˜ 0 is due primarily to changes to the electron diamagnetic rotation frequency ωe*. Linear plasma response modeling with the resistive MHD code m3d-c1 indicates that the tearing response location tracks the inward shift in ω⊥e ˜ 0. At pedestal ν*˜ 1, ELM suppression is also lost when the beam torque is reduced, but the ω⊥e change is dominated by collapse of the toroidal rotation vT. The hypothesis predicts that it should be possible to obtain ELM suppression at reduced beam torque by also reducing the height and width of the ωe* profile. This prediction has been confirmed experimentally with RMP ELM suppression at 0 Nm of beam torque and plasma normalized pressure βN ˜ 0.7. This opens the possibility of accessing ELM suppression in low torque ITER baseline plasmas by establishing suppression at low beta and then increasing beta while relying on the strong RMP-island coupling to maintain suppression.
Iorga, G.; Hitzenberger, R.; Kasper-Giebl, A.; Puxbaum, Hans
2007-01-01
In view of both the climatic relevance of aerosols and the fact that aerosol burdens in central Europe are heavily impacted by anthropogenic sources, this study is focused on estimating the regional-scale direct radiative effect of aerosols in Austria. The aerosol data (over 80 samples in total) were collected during measurement campaigns at five sampling sites: the urban areas of Vienna, Linz, and Graz and on Mt. Rax (1644 m, regional background aerosol) and Mt. Sonnblick (3106 m, background aerosol). Aerosol mass size distributions were obtained with eight-stage (size range: 0.06-16 μm diameter) and six-stage (size range 0.1-10 μm) low-pressure cascade impactors. The size-segregated samples were analyzed for total carbon (TC), black carbon (BC), and inorganic ions. The aerosol at these five locations is compared in terms of size distributions, optical properties, and direct forcing. Mie calculations are performed for the dry aerosol at 60 wavelengths in the range 0.3-40 μm. Using mass growth factors determined earlier, the optical properties are also estimated for higher relative humidities (60%, 70%, 80%, and 90%). A box model was used to estimate direct radiative forcing (DRF). The presence of absorbing species (BC) was found to reduce the cooling effect of the aerosols. The water-soluble substances dominate radiative forcing at the urban sites, while on Rax and Sonnblick BC plays the most important role. This result can be explained by the effect of the surface albedo, which is much lower in the urban regions (0.16) than at the ice and snow-covered mountain sites. Shortwave (below 4 μm) and longwave surface albedo values for ice were 0.35 and 0.5, while for snow surface albedo, values of 0.8 (shortwave) and 0.5 (longwave) were used. In the case of dry aerosol, especially for urban sites, the unidentified material may contribute a large part to the forcing. Depending on the sampling site the estimated forcing gets more negative with increasing humidity
Directory of Open Access Journals (Sweden)
Etsuji Suzuki
Full Text Available BACKGROUND: Multilevel analyses are ideally suited to assess the effects of ecological (higher level and individual (lower level exposure variables simultaneously. In applying such analyses to measures of ecologies in epidemiological studies, individual variables are usually aggregated into the higher level unit. Typically, the aggregated measure includes responses of every individual belonging to that group (i.e. it constitutes a self-included measure. More recently, researchers have developed an aggregate measure which excludes the response of the individual to whom the aggregate measure is linked (i.e. a self-excluded measure. In this study, we clarify the substantive and technical properties of these two measures when they are used as exposures in multilevel models. METHODS: Although the differences between the two aggregated measures are mathematically subtle, distinguishing between them is important in terms of the specific scientific questions to be addressed. We then show how these measures can be used in two distinct types of multilevel models-self-included model and self-excluded model-and interpret the parameters in each model by imposing hypothetical interventions. The concept is tested on empirical data of workplace social capital and employees' systolic blood pressure. RESULTS: Researchers assume group-level interventions when using a self-included model, and individual-level interventions when using a self-excluded model. Analytical re-parameterizations of these two models highlight their differences in parameter interpretation. Cluster-mean centered self-included models enable researchers to decompose the collective effect into its within- and between-group components. The benefit of cluster-mean centering procedure is further discussed in terms of hypothetical interventions. CONCLUSIONS: When investigating the potential roles of aggregated variables, researchers should carefully explore which type of model-self-included or self
Bajzer, Željko; Gibbons, Simon J; Coleman, Heidi D; Linden, David R; Farrugia, Gianrico
2015-08-01
Noninvasive breath tests for gastric emptying are important techniques for understanding the changes in gastric motility that occur in disease or in response to drugs. Mice are often used as an animal model; however, the gamma variate model currently used for data analysis does not always fit the data appropriately. The aim of this study was to determine appropriate mathematical models to better fit mouse gastric emptying data including when two peaks are present in the gastric emptying curve. We fitted 175 gastric emptying data sets with two standard models (gamma variate and power exponential), with a gamma variate model that includes stretched exponential and with a proposed two-component model. The appropriateness of the fit was assessed by the Akaike Information Criterion. We found that extension of the gamma variate model to include a stretched exponential improves the fit, which allows for a better estimation of T1/2 and Tlag. When two distinct peaks in gastric emptying are present, a two-component model is required for the most appropriate fit. We conclude that use of a stretched exponential gamma variate model and when appropriate a two-component model will result in a better estimate of physiologically relevant parameters when analyzing mouse gastric emptying data.
Baseline LAW Glass Formulation Testing
Energy Technology Data Exchange (ETDEWEB)
Kruger, Albert A. [USDOE Office of River Protection, Richland, WA (United States); Mooers, Cavin [The Catholic University of America, Washington, DC (United States). Vitreous State Lab.; Bazemore, Gina [The Catholic University of America, Washington, DC (United States). Vitreous State Lab; Pegg, Ian L. [The Catholic University of America, Washington, DC (United States). Vitreous State Lab; Hight, Kenneth [The Catholic University of America, Washington, DC (United States). Vitreous State Lab; Lai, Shan Tao [The Catholic University of America, Washington, DC (United States). Vitreous State Lab; Buechele, Andrew [The Catholic University of America, Washington, DC (United States). Vitreous State Lab; Rielley, Elizabeth [The Catholic University of America, Washington, DC (United States). Vitreous State Lab; Gan, Hao [The Catholic University of America, Washington, DC (United States). Vitreous State Lab; Muller, Isabelle S. [The Catholic University of America, Washington, DC (United States). Vitreous State Lab; Cecil, Richard [The Catholic University of America, Washington, DC (United States). Vitreous State Lab
2013-06-13
The major objective of the baseline glass formulation work was to develop and select glass formulations that are compliant with contractual and processing requirements for each of the LAW waste streams. Other objectives of the work included preparation and characterization of glasses with respect to the properties of interest, optimization of sulfate loading in the glasses, evaluation of ability to achieve waste loading limits, testing to demonstrate compatibility of glass melts with melter materials of construction, development of glass formulations to support ILAW qualification activities, and identification of glass formulation issues with respect to contract specifications and processing requirements.
DEFF Research Database (Denmark)
Flores Alsina, Xavier; Comas, J.; Rodriquez-Roda, I.
2009-01-01
The main objective of this paper is to demonstrate how including the occurrence of filamentous bulking sludge in a secondary clarifier model will affect the predicted process performance during the simulation of WWTPs. The IWA Benchmark Simulation Model No. 2 (BSM2) is hereby used as a simulation...
Directory of Open Access Journals (Sweden)
Christopher P. Paolini
2012-01-01
Full Text Available The ideal gas (IG model is probably the most well-known gas models in engineering thermodynamics. In this paper, we extend the IG model into an ideal gas equilibrium (IGE model mixture model by incorporating chemical equilibrium calculations as part of the state evaluation. Through a simple graphical interface, users can set the atomic composition of a gas mixture. We have integrated this model into a thermodynamic web portal TEST (http://thermofluids.sdsu.edu/ that contains Java applets for various models for properties of pure substances. In the state panel of the IGE model, the known thermodynamic properties are entered. For a given pressure and temperature, the mixture's Gibbs function is minimized subject to atomic constraints and the equilibrium composition along with thermodynamic properties of the mixture are calculated and displayed. What is unique about this approach is that equilibrium computations are performed in the background, without requiring any major change in the familiar user interface used in other state daemons. Properties calculated by this equilibrium state daemon are compared with results from other established applications such as NASA CEA and STANJAN. Also, two different algorithms, an iterative approach and a direct approach based on minimizing different thermodynamic functions in different situation, are compared.
Reerink, Thomas J.; Jan Van De Berg, Willem; Van De Wal, Roderik S W
2016-01-01
This paper accompanies the second OBLIMAP open-source release. The package is developed to map climate fields between a general circulation model (GCM) and an ice sheet model (ISM) in both directions by using optimal aligned oblique projections, which minimize distortions. The curvature of the surfa
TAPIR--Finnish national geochemical baseline database.
Jarva, Jaana; Tarvainen, Timo; Reinikainen, Jussi; Eklund, Mikael
2010-09-15
In Finland, a Government Decree on the Assessment of Soil Contamination and Remediation Needs has generated a need for reliable and readily accessible data on geochemical baseline concentrations in Finnish soils. According to the Decree, baseline concentrations, referring both to the natural geological background concentrations and the diffuse anthropogenic input of substances, shall be taken into account in the soil contamination assessment process. This baseline information is provided in a national geochemical baseline database, TAPIR, that is publicly available via the Internet. Geochemical provinces with elevated baseline concentrations were delineated to provide regional geochemical baseline values. The nationwide geochemical datasets were used to divide Finland into geochemical provinces. Several metals (Co, Cr, Cu, Ni, V, and Zn) showed anomalous concentrations in seven regions that were defined as metal provinces. Arsenic did not follow a similar distribution to any other elements, and four arsenic provinces were separately determined. Nationwide geochemical datasets were not available for some other important elements such as Cd and Pb. Although these elements are included in the TAPIR system, their distribution does not necessarily follow the ones pre-defined for metal and arsenic provinces. Regional geochemical baseline values, presented as upper limit of geochemical variation within the region, can be used as trigger values to assess potential soil contamination. Baseline values have also been used to determine upper and lower guideline values that must be taken into account as a tool in basic risk assessment. If regional geochemical baseline values are available, the national guideline values prescribed in the Decree based on ecological risks can be modified accordingly. The national geochemical baseline database provides scientifically sound, easily accessible and generally accepted information on the baseline values, and it can be used in various
FED baseline engineering studies report
Energy Technology Data Exchange (ETDEWEB)
Sager, P.H.
1983-04-01
Studies were carried out on the FED Baseline to improve design definition, establish feasibility, and reduce cost. Emphasis was placed on cost reduction, but significant feasibility concerns existed in several areas, and better design definition was required to establish feasibility and provide a better basis for cost estimates. Design definition and feasibility studies included the development of a labyrinth shield ring concept to prevent radiation streaming between the torus spool and the TF coil cryostat. The labyrinth shield concept which was developed reduced radiation streaming sufficiently to permit contact maintenance of the inboard EF coils. Various concepts of preventing arcing between adjacent shield sectors were also explored. It was concluded that installation of copper straps with molybdenum thermal radiation shields would provide the most reliable means of preventing arcing. Other design studies included torus spool electrical/structural concepts, test module shielding, torus seismic response, poloidal conditions in the magnets, disruption characteristics, and eddy current effects. These additional studies had no significant impact on cost but did confirm the feasibility of the basic FED Baseline concept.
Directory of Open Access Journals (Sweden)
Smieszek Timo
2009-11-01
Full Text Available Abstract Background Mathematical models and simulations of disease spread often assume a constant per-contact transmission probability. This assumption ignores the heterogeneity in transmission probabilities, e.g. due to the varying intensity and duration of potentially contagious contacts. Ignoring such heterogeneities might lead to erroneous conclusions from simulation results. In this paper, we show how a mechanistic model of disease transmission differs from this commonly used assumption of a constant per-contact transmission probability. Methods We present an exposure-based, mechanistic model of disease transmission that reflects heterogeneities in contact duration and intensity. Based on empirical contact data, we calculate the expected number of secondary cases induced by an infector (i for the mechanistic model and (ii under the classical assumption of a constant per-contact transmission probability. The results of both approaches are compared for different basic reproduction numbers R0. Results The outcomes of the mechanistic model differ significantly from those of the assumption of a constant per-contact transmission probability. In particular, cases with many different contacts have much lower expected numbers of secondary cases when using the mechanistic model instead of the common assumption. This is due to the fact that the proportion of long, intensive contacts decreases in the contact dataset with an increasing total number of contacts. Conclusion The importance of highly connected individuals, so-called super-spreaders, for disease spread seems to be overestimated when a constant per-contact transmission probability is assumed. This holds particularly for diseases with low basic reproduction numbers. Simulations of disease spread should weight contacts by duration and intensity.
Long Baseline Neutrino Experiments
Mezzetto, Mauro
2016-05-01
Following the discovery of neutrino oscillations by the Super-Kamiokande collaboration, recently awarded with the Nobel Prize, two generations of long baseline experiments had been setup to further study neutrino oscillations. The first generation experiments, K2K in Japan, Minos in the States and Opera in Europe, focused in confirming the Super-Kamiokande result, improving the precision with which oscillation parameters had been measured and demonstrating the ντ appearance process. Second generation experiments, T2K in Japan and very recently NOνA in the States, went further, being optimized to look for genuine three neutrino phenomena like non-zero values of θ13 and first glimpses to leptonic CP violation (LCPV) and neutrino mass ordering (NMO). The discovery of leptonic CP violation will require third generation setups, at the moment two strong proposals are ongoing, Dune in the States and Hyper-Kamiokande in Japan. This review will focus a little more in these future initiatives.
Energy Technology Data Exchange (ETDEWEB)
Hamelinck, C.; Koper, M.; Berndes, G.; Englund, O.; Diaz-Chavez, R.; Kunen, E.; Walden, D.
2011-10-15
The European Union is promoting the use of biofuels and other renewable energy in transport. In April 2009, the Renewable Energy Directive (2009/28/EC) was adopted that set a 10% target for renewable energy in transport in 2020. The directive sets several requirements to the sustainability of biofuels marketed in the frame of the Directive. The Commission is required to report to the European Parliament on a regular basis on a range of sustainability impacts resulting from the use of biofuels in the EU. This report serves as a baseline of information for regular monitoring on the impacts of the Directive. Chapter 2 discusses the EU biofuels market, the production and consumption of biofuels and international trade. It is derived where the feedstock for EU consumed biofuels originally come from. Chapter 3 discusses the biofuel policy framework in the EU and major third countries of supply. It looks at various policy aspects that are relevant to comply with the EU sustainability requirements. Chapter 4 discusses the environmental and social sustainability aspects associated with EU biofuels and their feedstock. Chapter 5 discusses the macro-economic effects that indirectly result from increased EU biofuels consumption, on commodity prices and land use. Chapter 6 presents country factsheets for main third countries that supplied biofuels to the EU market in 2008.
Mathematical Model of Two Phase Flow in Natural Draft Wet-Cooling Tower Including Flue Gas Injection
Directory of Open Access Journals (Sweden)
Hyhlík Tomáš
2016-01-01
Full Text Available The previously developed model of natural draft wet-cooling tower flow, heat and mass transfer is extended to be able to take into account the flow of supersaturated moist air. The two phase flow model is based on void fraction of gas phase which is included in the governing equations. Homogeneous equilibrium model, where the two phases are well mixed and have the same velocity, is used. The effect of flue gas injection is included into the developed mathematical model by using source terms in governing equations and by using momentum flux coefficient and kinetic energy flux coefficient. Heat and mass transfer in the fill zone is described by the system of ordinary differential equations, where the mass transfer is represented by measured fill Merkel number and heat transfer is calculated using prescribed Lewis factor.
Life Support Baseline Values and Assumptions Document
Anderson, Molly S.; Ewert, Michael K.; Keener, John F.; Wagner, Sandra A.
2015-01-01
The Baseline Values and Assumptions Document (BVAD) provides analysts, modelers, and other life support researchers with a common set of values and assumptions which can be used as a baseline in their studies. This baseline, in turn, provides a common point of origin from which many studies in the community may depart, making research results easier to compare and providing researchers with reasonable values to assume for areas outside their experience. With the ability to accurately compare different technologies' performance for the same function, managers will be able to make better decisions regarding technology development.
Raksharam; Dutta, Aloke K.
2017-04-01
In this paper, a unified analytical model for the drain current of a symmetric Double-Gate Junctionless Field-Effect Transistor (DG-JLFET) is presented. The operation of the device has been classified into four modes: subthreshold, semi-depleted, accumulation, and hybrid; with the main focus of this work being on the accumulation mode, which has not been dealt with in detail so far in the literature. A physics-based model, using a simplified one-dimensional approach, has been developed for this mode, and it has been successfully integrated with the model for the hybrid mode. It also includes the effect of carrier mobility degradation due to the transverse electric field, which was hitherto missing in the earlier models reported in the literature. The piece-wise models have been unified using suitable interpolation functions. In addition, the model includes two most important short-channel effects pertaining to DG-JLFETs, namely the Drain Induced Barrier Lowering (DIBL) and the Subthreshold Swing (SS) degradation. The model is completely analytical, and is thus computationally highly efficient. The results of our model have shown an excellent match with those obtained from TCAD simulations for both long- and short-channel devices, as well as with the experimental data reported in the literature.
Dipole model analysis of highest precision HERA data, including very low Q{sup 2}'s
Energy Technology Data Exchange (ETDEWEB)
Luszczak, A. [Cracow Univ. of Technology (Poland); Kowalski, H. [Deutsches Elektronen-Synchrotron (DESY), Hamburg (Germany)
2016-12-15
We analyse, within a dipole model, the final, inclusive HERA DIS cross section data in the low χ region, using fully correlated errors. We show, that these highest precision data are very well described within the dipole model framework starting from Q{sup 2} values of 3.5 GeV{sup 2} to the highest values of Q{sup 2}=250 GeV{sup 2}. To analyze the saturation effects we evaluated the data including also the very low 0.35including this region show a preference of the saturation ansatz.
McLerran, Larry
2016-01-01
We modify the McLerran-Venugopalan model to include only a finite number of sources of color charge. We argue that Coulombic interactions between these color charges generates a source-source correlation function that properly includes the effects of color charge screening, a generalization of Debye screening for the Color Glass Condensate. Such a model may be useful for computing angular harmonics of flow measured in high energy hadron collisions for small systems. In this paper we provide a basic formulation of the problem on a lattice.
Dynamic model of a micro-tubular solid oxide fuel cell stack including an integrated cooling system
Hering, Martin; Brouwer, Jacob; Winkler, Wolfgang
2017-02-01
A novel dynamic micro-tubular solid oxide fuel cell (MT-SOFC) and stack model including an integrated cooling system is developed using a quasi three-dimensional, spatially resolved, transient thermodynamic, physical and electrochemical model that accounts for the complex geometrical relations between the cells and cooling-tubes. The modeling approach includes a simplified tubular geometry and stack design including an integrated cooling structure, detailed pressure drop and gas property calculations, the electrical and physical constraints of the stack design that determine the current, as well as control strategies for the temperature. Moreover, an advanced heat transfer balance with detailed radiative heat transfer between the cells and the integrated cooling-tubes, convective heat transfer between the gas flows and the surrounding structures and conductive heat transfer between the solid structures inside of the stack, is included. The detailed model can be used as a design basis for the novel MT-SOFC stack assembly including an integrated cooling system, as well as for the development of a dynamic system control strategy. The evaluated best-case design achieves very high electrical efficiency between around 75 and 55% in the entire power density range between 50 and 550 mW /cm2 due to the novel stack design comprising an integrated cooling structure.
40 CFR 80.90 - Conventional gasoline baseline emissions determination.
2010-07-01
... gasoline baseline emissions determination. (a) Annual average baseline values. For any facility of a... gasoline volume of the facility, per § 80.91. (b) Baseline exhaust benzene emissions—simple model. (1) Simple model exhaust benzene emissions of conventional gasoline shall be determined using the following...
Precise baseline determination for the TanDEM-X mission
Koenig, Rolf; Moon, Yongjin; Neumayer, Hans; Wermuth, Martin; Montenbruck, Oliver; Jäggi, Adrian
The TanDEM-X mission will strive for generating a global precise Digital Elevation Model (DEM) by way of bi-static SAR in a close formation of the TerraSAR-X satellite, already launched on June 15, 2007, and the TanDEM-X satellite to be launched in May 2010. Both satellites carry the Tracking, Occultation and Ranging (TOR) payload supplied by the GFZ German Research Centre for Geosciences. The TOR consists of a high-precision dual-frequency GPS receiver, called Integrated GPS Occultation Receiver (IGOR), and a Laser retro-reflector (LRR) for precise orbit determination (POD) and atmospheric sounding. The IGOR is of vital importance for the TanDEM-X mission objectives as the millimeter level determination of the baseline or distance between the two spacecrafts is needed to derive meter level accurate DEMs. Within the TanDEM-X ground segment GFZ is responsible for the operational provision of precise baselines. For this GFZ uses two software chains, first its Earth Parameter and Orbit System (EPOS) software and second the BERNESE software, for backup purposes and quality control. In a concerted effort also the German Aerospace Center (DLR) generates precise baselines independently with a dedicated Kalman filter approach realized in its FRNS software. By the example of GRACE the generation of baselines with millimeter accuracy from on-board GPS data can be validated directly by way of comparing them to the intersatellite K-band range measurements. The K-band ranges are accurate down to the micrometer-level and therefore may be considered as truth. Both TanDEM-X baseline providers are able to generate GRACE baselines with sub-millimeter accuracy. By merging the independent baselines by GFZ and DLR, the accuracy can even be increased. The K-band validation however covers solely the along-track component as the K-band data measure just the distance between the two GRACE satellites. In addition they inhibit an un-known bias which must be modelled in the comparison, so the
McLerran, Larry; Skokov, Vladimir V.
2017-01-01
We modify the McLerran-Venugopalan model to include only a finite number of sources of color charge. In the effective action for such a system of a finite number of sources, there is a point-like interaction and a Coulombic interaction. The point interaction generates the standard fluctuation term in the McLerran-Venugopalan model. The Coulomb interaction generates the charge screening originating from well known evolution in x. Such a model may be useful for computing angular harmonics of flow measured in high energy hadron collisions for small systems. In this paper we provide a basic formulation of the problem on a lattice.
Energy Technology Data Exchange (ETDEWEB)
Zhang, Hongbin [Idaho National Lab. (INL), Idaho Falls, ID (United States); Szilard, Ronaldo [Idaho National Lab. (INL), Idaho Falls, ID (United States); Epiney, Aaron [Idaho National Lab. (INL), Idaho Falls, ID (United States); Parisi, Carlo [Idaho National Lab. (INL), Idaho Falls, ID (United States); Vaghetto, Rodolfo [Texas A & M Univ., College Station, TX (United States); Vanni, Alessandro [Texas A & M Univ., College Station, TX (United States); Neptune, Kaleb [Texas A & M Univ., College Station, TX (United States)
2017-06-01
Under the auspices of the DOE LWRS Program RISMC Industry Application ECCS/LOCA, INL has engaged staff from both South Texas Project (STP) and the Texas A&M University (TAMU) to produce a generic pressurized water reactor (PWR) model including reactor core, clad/fuel design and systems thermal hydraulics based on the South Texas Project (STP) nuclear power plant, a 4-Loop Westinghouse PWR. A RISMC toolkit, named LOCA Toolkit for the U.S. (LOTUS), has been developed for use in this generic PWR plant model to assess safety margins for the proposed NRC 10 CFR 50.46c rule, Emergency Core Cooling System (ECCS) performance during LOCA. This demonstration includes coupled analysis of core design, fuel design, thermalhydraulics and systems analysis, using advanced risk analysis tools and methods to investigate a wide range of results. Within this context, a multi-physics best estimate plus uncertainty (MPBEPU) methodology framework is proposed.
Lagi, Marco; Bertrand, Karla Z; Bar-Yam, Yaneer
2012-01-01
Increases in global food prices have led to widespread hunger and social unrest---and an imperative to understand their causes. In a previous paper published in September 2011, we constructed for the first time a dynamic model that quantitatively agreed with food prices. Specifically, the model fit the FAO Food Price Index time series from January 2004 to March 2011, inclusive. The results showed that the dominant causes of price increases during this period were investor speculation and ethanol conversion. The model included investor trend following as well as shifting between commodities, equities and bonds to take advantage of increased expected returns. Here, we extend the food prices model to January 2012, without modifying the model but simply continuing its dynamics. The agreement is still precise, validating both the descriptive and predictive abilities of the analysis. Policy actions are needed to avoid a third speculative bubble that would cause prices to rise above recent peaks by the end of 2012.
Directory of Open Access Journals (Sweden)
Wendi Liu
2015-01-01
Full Text Available The aim of the present study is to apply simple ODE models in the area of modeling the spread of emerging infectious diseases and show the importance of model selection in estimating parameters, the basic reproduction number, turning point, and final size. To quantify the plausibility of each model, given the data and the set of four models including Logistic, Gompertz, Rosenzweg, and Richards models, the Bayes factors are calculated and the precise estimates of the best fitted model parameters and key epidemic characteristics have been obtained. In particular, for Ebola the basic reproduction numbers are 1.3522 (95% CI (1.3506, 1.3537, 1.2101 (95% CI (1.2084, 1.2119, 3.0234 (95% CI (2.6063, 3.4881, and 1.9018 (95% CI (1.8565, 1.9478, the turning points are November 7,November 17, October 2, and November 3, 2014, and the final sizes until December 2015 are 25794 (95% CI (25630, 25958, 3916 (95% CI (3865, 3967, 9886 (95% CI (9740, 10031, and 12633 (95% CI (12515, 12750 for West Africa, Guinea, Liberia, and Sierra Leone, respectively. The main results confirm that model selection is crucial in evaluating and predicting the important quantities describing the emerging infectious diseases, and arbitrarily picking a model without any consideration of alternatives is problematic.
Directory of Open Access Journals (Sweden)
Moonen Marie
2011-09-01
Full Text Available Abstract Background Valve dysfunction is a common cardiovascular pathology. Despite significant clinical research, there is little formal study of how valve dysfunction affects overall circulatory dynamics. Validated models would offer the ability to better understand these dynamics and thus optimize diagnosis, as well as surgical and other interventions. Methods A cardiovascular and circulatory system (CVS model has already been validated in silico, and in several animal model studies. It accounts for valve dynamics using Heaviside functions to simulate a physiologically accurate "open on pressure, close on flow" law. However, it does not consider real-time valve opening dynamics and therefore does not fully capture valve dysfunction, particularly where the dysfunction involves partial closure. This research describes an updated version of this previous closed-loop CVS model that includes the progressive opening of the mitral valve, and is defined over the full cardiac cycle. Results Simulations of the cardiovascular system with healthy mitral valve are performed, and, the global hemodynamic behaviour is studied compared with previously validated results. The error between resulting pressure-volume (PV loops of already validated CVS model and the new CVS model that includes the progressive opening of the mitral valve is assessed and remains within typical measurement error and variability. Simulations of ischemic mitral insufficiency are also performed. Pressure-Volume loops, transmitral flow evolution and mitral valve aperture area evolution follow reported measurements in shape, amplitude and trends. Conclusions The resulting cardiovascular system model including mitral valve dynamics provides a foundation for clinical validation and the study of valvular dysfunction in vivo. The overall models and results could readily be generalised to other cardiac valves.
A comparison of baseline methodologies for 'Reducing Emissions from Deforestation and Degradation'
Directory of Open Access Journals (Sweden)
Kok Kasper
2009-07-01
Full Text Available Abstract Background A mechanism for emission reductions from deforestation and degradation (REDD is very likely to be included in a future climate agreement. The choice of REDD baseline methodologies will crucially influence the environmental and economic effectiveness of the climate regime. We compare three different historical baseline methods and one innovative dynamic model baseline approach to appraise their applicability under a future REDD policy framework using a weighted multi-criteria analysis. Results The results show that each baseline method has its specific strengths and weaknesses. Although the dynamic model allows for the best environmental and for comparatively good economic performance, its high demand for data and technical capacity limit the current applicability in many developing countries. Conclusion The adoption of a multi-tier approach will allow countries to select the baseline method best suiting their specific capabilities and data availability while simultaneously ensuring scientific transparency, environmental effectiveness and broad political support.
Cich, Matthew J.; Guillaume, Alexandre; Drouin, Brian; Benner, D. Chris
2017-06-01
Multispectrum analysis can be a challenge for a variety of reasons. It can be computationally intensive to fit a proper line shape model especially for high resolution experimental data. Band-wide analyses including many transitions along with interactions, across many pressures and temperatures are essential to accurately model, for example, atmospherically relevant systems. Labfit is a fast multispectrum analysis program originally developed by D. Chris Benner with a text-based interface. More recently at JPL a graphical user interface was developed with the goal of increasing the ease of use but also the number of potential users. The HTP lineshape model has been added to Labfit keeping it up-to-date with community standards. Recent analyses using labfit will be shown to demonstrate its ability to competently handle large experimental datasets, including high order lineshape effects, that are otherwise unmanageable.
Anderson, Benjamin
2013-01-01
All observations of photodegradation and self healing follow the predictions of the correlated chromophore domain model. [Ramini et.al. Polym. Chem., 2013, 4, 4948.] In the present work, we generalize the domain model to describe the effects of an electric field by including induced dipole interactions between molecules in a domain by means of a self-consistent field approach. This electric field correction is added to the statistical mechanical model to calculate the distribution of domains that are central to healing. Also included in the model are the dynamics due to the formation of an irreversibly damaged species. As in previous studies, the model with a one-dimensional domain best explains all experimental data of the population as a function of time, temperature, intensity, concentration, and now applied electric field. Though the nature of a domain is yet to be determined, the fact that only one-dimensional domain models are consistent with observations suggests that they might be made of correlated d...
Reerink, Thomas J.; van de Berg, Willem Jan; van de Wal, Roderik S. W.
2016-11-01
This paper accompanies the second OBLIMAP open-source release. The package is developed to map climate fields between a general circulation model (GCM) and an ice sheet model (ISM) in both directions by using optimal aligned oblique projections, which minimize distortions. The curvature of the surfaces of the GCM and ISM grid differ, both grids may be irregularly spaced and the ratio of the grids is allowed to differ largely. OBLIMAP's stand-alone version is able to map data sets that differ in various aspects on the same ISM grid. Each grid may either coincide with the surface of a sphere, an ellipsoid or a flat plane, while the grid types might differ. Re-projection of, for example, ISM data sets is also facilitated. This is demonstrated by relevant applications concerning the major ice caps. As the stand-alone version also applies to the reverse mapping direction, it can be used as an offline coupler. Furthermore, OBLIMAP 2.0 is an embeddable GCM-ISM coupler, suited for high-frequency online coupled experiments. A new fast scan method is presented for structured grids as an alternative for the former time-consuming grid search strategy, realising a performance gain of several orders of magnitude and enabling the mapping of high-resolution data sets with a much larger number of grid nodes. Further, a highly flexible masked mapping option is added. The limitation of the fast scan method with respect to unstructured and adaptive grids is discussed together with a possible future parallel Message Passing Interface (MPI) implementation.
A Physics-Based Charge-Control Model for InP DHBT Including Current-Blocking Effect
Institute of Scientific and Technical Information of China (English)
GE Ji; JIN Zhi; SU Yong-Bo; CHENG Wei; WANG Xian-Wai; CHEN Gao-Peng; LIU Xin-Yu
2009-01-01
We develop a physics-based charge-control InP double heterojunction bipolar transistor model including three important effects: current blocking, mobile-charge modulation of the base-collector capacitance and velocity-field modulation in the transit time. The bias-dependent base-collector depletion charge is obtained analytically, which takes into account the mobile-charge modulation. Then, a measurement based voltage-dependent transit time formulation is implemented. As a result, over a wide range of biases, the developed model shows good agreement between the modeled and measured S-parameters and cutoff frequency. Also, the model considering current blocking effect demonstrates more accurate prediction of the output characteristics than conventional vertical bipolar inter company results.
Directory of Open Access Journals (Sweden)
Yong Zhao
1997-01-01
Full Text Available A nonlinear three dimensional (3D single rack model and a nonlinear 3D whole pool multi-rack model are developed for the spent fuel storage racks of a nuclear power plant (NPP to determine impacts and frictional motion responses when subjected to 3D excitations from the supporting building floor. The submerged free standing rack system and surrounding water are coupled due to hydrodynamic fluid-structure interaction (FSI using potential theory. The models developed have features that allow consideration of geometric and material nonlinearities including (1 the impacts of fuel assemblies to rack cells, a rack to adjacent racks or pool walls, and rack support legs to the pool floor; (2 the hydrodynamic coupling of fuel assemblies with their storing racks, and of a rack with adjacent racks, pool walls, and the pool floor; and (3 the dynamic motion behavior of rocking, twisting, and frictional sliding of rack modules. Using these models 3D nonlinear time history dynamic analyses are performed per the U.S. Nuclear Regulatory Commission (USNRC criteria. Since few such modeling, analyses, and results using both the 3D single and whole pool multiple rack models are available in the literature, this paper emphasizes description of modeling and analysis techniques using the SOLVIA general purpose nonlinear finite element code. Typical response results with different Coulomb friction coefficients are presented and discussed.
Hanford Site technical baseline database. Revision 1
Energy Technology Data Exchange (ETDEWEB)
Porter, P.E.
1995-01-27
This report lists the Hanford specific files (Table 1) that make up the Hanford Site Technical Baseline Database. Table 2 includes the delta files that delineate the differences between this revision and revision 0 of the Hanford Site Technical Baseline Database. This information is being managed and maintained on the Hanford RDD-100 System, which uses the capabilities of RDD-100, a systems engineering software system of Ascent Logic Corporation (ALC). This revision of the Hanford Site Technical Baseline Database uses RDD-100 version 3.0.2.2 (see Table 3). Directories reflect those controlled by the Hanford RDD-100 System Administrator. Table 4 provides information regarding the platform. A cassette tape containing the Hanford Site Technical Baseline Database is available.
Energy Technology Data Exchange (ETDEWEB)
Montanari, David [FERMILAB; Adamowski, Mark [Fermilab; Bremer, Johan [CERN; Delaney, Michael [Fermilab; Aurelien, Diaz [CERN; Doubnik, Roza [Fermilab; Haaf, Kevin [Fermilab; Hentschel, Steve [Fermilab; Norris, Barry [Fermilab; Voirin, Erik [Fermilab
2017-03-09
The Deep Underground Neutrino Experiment (DUNE) collaboration is developing a multi-kiloton Long-Baseline neutrino experiment that will be located one mile underground at the Sanford Underground Research Facility (SURF) in Lead, SD. In the present design, detectors will be located inside four cryostats filled with a total of 68,400 ton of ultrapure liquid argon, at the level of impurities lower than 100 parts per trillion of oxygen equivalent contamination. The Long-Baseline Neutrino Facility (LBNF) is developing the conventional facilities and cryogenics infrastructure supporting this experiment. The cryogenics system is composed of several sub-systems: External/Infrastructure, Proximity, and Internal cryogenics. It will be engineered, manufactured, commissioned, and qualified by an international engineering team. This contribution highlights the main features of the LBNF cryogenic system. It presents its performance, functional requirements and modes of operations. As a result, it also details the status of the design, present and future needs.
Rationing in the presence of baselines
DEFF Research Database (Denmark)
Hougaard, Jens Leth; Moreno-Ternero, Juan D.; Østerdal, Lars Peter
2013-01-01
We analyze a general model of rationing in which agents have baselines, in addition to claims against the (insufficient) endowment of the good to be allocated. Many real-life problems fit this general model (e.g., bankruptcy with prioritized claims, resource allocation in the public health care...
Kharin, Stanislav; Sarsengeldin, Merey; Kassabek, Samat
2016-08-01
We represent mathematical models of electromagnetic field dynamics and heat transfer in closed symmetric and asymmetric electrical contacts including Thomson effect, which are essentially nonlinear due to the dependence of thermal and electrical conductivities on temperature. Suggested solutions are based on the assumption of identity of equipotentials and isothermal surfaces, which agrees with experimental data and valid for both linear and nonlinear cases. Well known Kohlrausch temperature-potential relation is analytically justified.
Svendsen, B.; Hutter, K.; Laloui, L.
This work deals with the thermodynamic formulation of constitutive models for materials whose quasi-static behaviour is governed by internal friction, e.g., dry granular materials. The process of internal friction is represented here phenomenologically with the help of a second-order, symmetric-tensor-valued internal variable. A general class of models for the evolution of this variable is considered, including as special cases a hypoelastic-like form for this relation as well as the hypoplastic form of Kolymbas (1991). The thermodynamic formulation is carried out in the context of the Müller-Liu entropy principle. Among other things, it is shown that for the hypoelastic-type models, a true equilibrium inelastic Cauchy stress exists. On the other hand, such a stress does not exist for the hypoplastic model due to its rate-independence and incremental non-linearity. With the help of a slight generalization of the notion of thermodynamic equilibrium, i.e., to thermodynamic ``quasi-equilibrium,'' however, such a Cauchy stress can be formulated for the hypoplastic model. As it turns out, this quasi-equilibrium for the Cauchy stress represents a thermodynamic generalization of the so-called quasi-static stress postulated for example by Goddard (1986) in the context of his viscoplastic model for a frictional-dissipative, and in particular for granular, materials.
Institute of Scientific and Technical Information of China (English)
吴建松; 张辉; 杨锐
2013-01-01
This paper applies the meshfree Smoothed Particle Hydrodynamics (SPH) method with Graphical Processing Unit (GPU) parallel computing technique to investigate the highly complex 3-D dam-break flow in urban areas including underground spaces. Taking the advantage of GPUs parallel computing techniques, simulations involving more than 107 particles can be achieved. We use a virtual geometric plane boundary to handle the outermost solid wall in order to save considerable video card memory for the GPU computing. To evaluate the accuracy of the new GPU-based SPH model, qualitative and quantitative comparison to a real flooding experiment is performed and the results of a numerical model based on Shallow Water Equations (SWEs) is given with good accu- racy. With the new GPU-based SPH model, the effects of the building layouts and underground spaces on the propagation of dam- break flood through an intricate city layout are examined.
Sakowski, Barbara; Edwards, Daryl; Dickens, Kevin
2014-01-01
Modeling droplet condensation via CFD codes can be very tedious, time consuming, and inaccurate. CFD codes may be tedious and time consuming in terms of using Lagrangian particle tracking approaches or particle sizing bins. Also since many codes ignore conduction through the droplet and or the degradating effect of heat and mass transfer if noncondensible species are present, the solutions may be inaccurate. The modeling of a condensing spray chamber where the significant size of the water droplets and the time and distance these droplets take to fall, can make the effect of droplet conduction a physical factor that needs to be considered in the model. Furthermore the presence of even a relatively small amount of noncondensible has been shown to reduce the amount of condensation [Ref 1]. It is desirable then to create a modeling tool that addresses these issues. The path taken to create such a tool is illustrated. The application of this tool and subsequent results are based on the spray chamber in the Spacecraft Propulsion Research Facility (B2) located at NASA's Plum Brook Station that tested an RL-10 engine. The platform upon which the condensation physics is modeled is SINDAFLUINT. The use of SINDAFLUINT enables the ability to model various aspects of the entire testing facility, including the rocket exhaust duct flow and heat transfer to the exhaust duct wall. The ejector pumping system of the spray chamber is also easily implemented via SINDAFLUINT. The goal is to create a transient one dimensional flow and heat transfer model beginning at the rocket, continuing through the condensing spray chamber, and finally ending with the ejector pumping system. However the model of the condensing spray chamber may be run independently of the rocket and ejector systems detail, with only appropriate mass flow boundary conditions placed at the entrance and exit of the condensing spray chamber model. The model of the condensing spray chamber takes into account droplet
Cooper, B. P., Jr.
1979-01-01
A model for the boundary layer at the exit plane of a rocket nozzle was developed which, unlike most previous models, includes the subsonic sublayer. The equations for the flow near the nozzle exit plane are presented and the method by which the subsonic sublayer transitions to supersonic flow in the plume is described. The resulting model describes the entire boundary layer and can be used to provide a startline for method-of-characteristics calculations of plume flowfields. The model was incorporated into a method of characteristics computer program and comparisons of computed results to experimental data show good agreement. The data used in the comparisons were obtained in tests in which mass fluxes from a 22.2-N (5 lbf) thrust engine were measured at angles off the nozzle centerline of up to 150 deg. Additional comparisons were made with data obtained during tests of a 0.89-N (0.2 lbr) monopropellant thruster and from the OH-64 space shuttle heating tests. The agreement with the data indicates that the model can be used for calculating plume backflow properties.
Menke, William
2017-02-01
We prove that the problem of inverting Rayleigh wave phase velocity functions c( k ) , where k is wavenumber, for density ρ ( z ) , rigidity μ ( z ) and Lamé parameter λ ( z ) , where z is depth, is fully non-unique, at least in the highly-idealized case where the base Earth model is an isotropic half space. The model functions completely trade off. This is one special case of a common inversion scenario in which one seeks to determine several model functions from a single data function. We explore the circumstances under which this broad class of problems is unique, starting with very simple scenarios, building up to the somewhat more complicated (and common) case where data and model functions are related by convolutions, and then finally, to scale-independent problems (which include the Rayleigh wave problem). The idealized cases that we examine analytically provide insight into the kinds of nonuniqueness that are inherent in the much more complicated problems encountered in modern geophysical imaging (though they do not necessarily provide methods for solving those problems). We also define what is meant by a Backus and Gilbert resolution kernel in this kind of inversion and show under what circumstances a unique localized average of a single model function can be constructed.
Menke, William
2017-04-01
We prove that the problem of inverting Rayleigh wave phase velocity functions c( k ), where k is wavenumber, for density ρ ( z ), rigidity μ ( z ) and Lamé parameter λ ( z ), where z is depth, is fully non-unique, at least in the highly-idealized case where the base Earth model is an isotropic half space. The model functions completely trade off. This is one special case of a common inversion scenario in which one seeks to determine several model functions from a single data function. We explore the circumstances under which this broad class of problems is unique, starting with very simple scenarios, building up to the somewhat more complicated (and common) case where data and model functions are related by convolutions, and then finally, to scale-independent problems (which include the Rayleigh wave problem). The idealized cases that we examine analytically provide insight into the kinds of nonuniqueness that are inherent in the much more complicated problems encountered in modern geophysical imaging (though they do not necessarily provide methods for solving those problems). We also define what is meant by a Backus and Gilbert resolution kernel in this kind of inversion and show under what circumstances a unique localized average of a single model function can be constructed.
Time dependence of Fe/O ratio within a 3D Solar Energetic Particle propagation model including drift
Dalla, S; Zelina, P; Laitinen, T
2016-01-01
Context. The intensity profiles of iron and oxygen in Solar Energetic Particle (SEP) events often display differences that result in a decreasing Fe/O ratio over time. The physical mechanisms behind this behaviour are not fully understood, but these observational signatures provide important tests of physical modelling efforts. Aims. In this paper we study the propagation of iron and oxygen SEP ions using a 3D model of propagation which includes the effect of guiding centre drift in a Parker spiral magnetic field. We derive time intensity profiles for a variety of observer locations and study the temporal evolution of the Fe/O ratio. Methods. We use a 3D full orbit test particle model which includes scattering. The configuration of the interplanetary magnetic field is a unipolar Parker spiral. Particles are released instantaneously from a compact region at 2 solar radii and allowed to propagate in 3D. Results. Both Fe and O experience significant transport across the magnetic field due to gradient and curvatu...
Directory of Open Access Journals (Sweden)
Cong Guan
2015-06-01
Full Text Available In this article, the operation of a large two-stroke marine diesel engine including various cases with turbocharger cut-out was thoroughly investigated by using a modular zero-dimensional engine model built in MATLAB/Simulink environment. The model was developed by using as a basis an in-house modular mean value engine model, in which the existing cylinder block was replaced by a more detailed one that is capable of representing the scavenging ports-cylinder-exhaust valve processes. Simulation of the engine operation at steady state conditions was performed and the derived engine performance parameters were compared with the respective values obtained by the engine shop trials. The investigation of engine operation under turbocharger cut-out conditions in the region from 10% to 50% load was carried out and the influence of turbocharger cut-out on engine performance including the in-cylinder parameters was comprehensively studied. The recommended schedule for the combination of the turbocharger cut-out and blower activation was discussed for the engine operation under part load conditions. Finally, the influence of engine operating strategies on the annual fuel savings, CO2 emissions reduction and blower operating hours for a Panamax container ship operating at slow steaming conditions is presented and discussed.
Environmental baselines: preparing for shale gas in the UK
Bloomfield, John; Manamsa, Katya; Bell, Rachel; Darling, George; Dochartaigh, Brighid O.; Stuart, Marianne; Ward, Rob
2014-05-01
Groundwater is a vital source of freshwater in the UK. It provides almost 30% of public water supply on average, but locally, for example in south-east England, it is constitutes nearly 90% of public supply. In addition to public supply, groundwater has a number of other uses including agriculture, industry, and food and drink production. It is also vital for maintaining river flows especially during dry periods and so is essential for maintaining ecosystem health. Recently, there have been concerns expressed about the potential impacts of shale gas development on groundwater. The UK has abundant shales and clays which are currently the focus of considerable interest and there is active research into their characterisation, resource evaluation and exploitation risks. The British Geological Survey (BGS) is undertaking research to provide information to address some of the environmental concerns related to the potential impacts of shale gas development on groundwater resources and quality. The aim of much of this initial work is to establish environmental baselines, such as a baseline survey of methane occurrence in groundwater (National methane baseline study) and the spatial relationships between potential sources and groundwater receptors (iHydrogeology project), prior to any shale gas exploration and development. The poster describes these two baseline studies and presents preliminary findings. BGS are currently undertaking a national survey of baseline methane concentrations in groundwater across the UK. This work will enable any potential future changes in methane in groundwater associated with shale gas development to be assessed. Measurements of methane in potable water from the Cretaceous, Jurassic and Triassic carbonate and sandstone aquifers are variable and reveal methane concentrations of up to 500 micrograms per litre, but the mean value is relatively low at 2km. The geological modelling process will be presented and discussed along with maps combining
Statistical Mechanics of Node-perturbation Learning with Noisy Baseline
Hara, Kazuyuki; Katahira, Kentaro; Okada, Masato
2017-02-01
Node-perturbation learning is a type of statistical gradient descent algorithm that can be applied to problems where the objective function is not explicitly formulated, including reinforcement learning. It estimates the gradient of an objective function by using the change in the object function in response to the perturbation. The value of the objective function for an unperturbed output is called a baseline. Cho et al. proposed node-perturbation learning with a noisy baseline. In this paper, we report on building the statistical mechanics of Cho's model and on deriving coupled differential equations of order parameters that depict learning dynamics. We also show how to derive the generalization error by solving the differential equations of order parameters. On the basis of the results, we show that Cho's results are also apply in general cases and show some general performances of Cho's model.
2016 Annual Technology Baseline (ATB)
Energy Technology Data Exchange (ETDEWEB)
Cole, Wesley; Kurup, Parthiv; Hand, Maureen; Feldman, David; Sigrin, Benjamin; Lantz, Eric; Stehly, Tyler; Augustine, Chad; Turchi, Craig; O' Connor, Patrick; Waldoch, Connor
2016-09-01
Consistent cost and performance data for various electricity generation technologies can be difficult to find and may change frequently for certain technologies. With the Annual Technology Baseline (ATB), National Renewable Energy Laboratory provides an organized and centralized dataset that was reviewed by internal and external experts. It uses the best information from the Department of Energy laboratory's renewable energy analysts and Energy Information Administration information for conventional technologies. The ATB will be updated annually in order to provide an up-to-date repository of current and future cost and performance data. Going forward, we plan to revise and refine the values using best available information. The ATB includes both a presentation with notes (PDF) and an associated Excel Workbook. The ATB includes the following electricity generation technologies: land-based wind; offshore wind; utility-scale solar PV; concentrating solar power; geothermal power; hydropower plants (upgrades to existing facilities, powering non-powered dams, and new stream-reach development); conventional coal; coal with carbon capture and sequestration; integrated gasification combined cycle coal; natural gas combustion turbines; natural gas combined cycle; conventional biopower. Nuclear laboratory's renewable energy analysts and Energy Information Administration information for conventional technologies. The ATB will be updated annually in order to provide an up-to-date repository of current and future cost and performance data. Going forward, we plan to revise and refine the values using best available information.
Wai, Rong-Jong; Yang, Zhi-Wei
2008-10-01
This paper focuses on the development of adaptive fuzzy neural network control (AFNNC), including indirect and direct frameworks for an n-link robot manipulator, to achieve high-precision position tracking. In general, it is difficult to adopt a model-based design to achieve this control objective due to the uncertainties in practical applications, such as friction forces, external disturbances, and parameter variations. In order to cope with this problem, an indirect AFNNC (IAFNNC) scheme and a direct AFNNC (DAFNNC) strategy are investigated without the requirement of prior system information. In these model-free control topologies, a continuous-time Takagi-Sugeno (T-S) dynamic fuzzy model with online learning ability is constructed to represent the system dynamics of an n-link robot manipulator. In the IAFNNC, an FNN estimator is designed to tune the nonlinear dynamic function vector in fuzzy local models, and then, the estimative vector is used to indirectly develop a stable IAFNNC law. In the DAFNNC, an FNN controller is directly designed to imitate a predetermined model-based stabilizing control law, and then, the stable control performance can be achieved by only using joint position information. All the IAFNNC and DAFNNC laws and the corresponding adaptive tuning algorithms for FNN weights are established in the sense of Lyapunov stability analyses to ensure the stable control performance. Numerical simulations and experimental results of a two-link robot manipulator actuated by dc servomotors are given to verify the effectiveness and robustness of the proposed methodologies. In addition, the superiority of the proposed control schemes is indicated in comparison with proportional-differential control, fuzzy-model-based control, T-S-type FNN control, and robust neural fuzzy network control systems.
Tournier, Jean-Michel; El-Genk, Mohamed S.
1995-01-01
This report describes the user's manual for 'HPTAM,' a two-dimensional Heat Pipe Transient Analysis Model. HPTAM is described in detail in the UNM-ISNPS-3-1995 report which accompanies the present manual. The model offers a menu that lists a number of working fluids and wall and wick materials from which the user can choose. HPTAM is capable of simulating the startup of heat pipes from either a fully-thawed or frozen condition of the working fluid in the wick structure. The manual includes instructions for installing and running HPTAM on either a UNIX, MS-DOS or VMS operating system. Samples for input and output files are also provided to help the user with the code.
Plutonium Immobilization Project Baseline Formulation
Energy Technology Data Exchange (ETDEWEB)
Ebbinghaus, B.
1999-02-01
A key milestone for the Immobilization Project (AOP Milestone 3.2a) in Fiscal Year 1998 (FY98) is the definition of the baseline composition or formulation for the plutonium ceramic form. The baseline formulation for the plutonium ceramic product must be finalized before the repository- and plant-related process specifications can be determined. The baseline formulation that is currently specified is given in Table 1.1. In addition to the baseline formulation specification, this report provides specifications for two alternative formulations, related compositional specifications (e.g., precursor compositions and mixing recipes), and other preliminary form and process specifications that are linked to the baseline formulation. The preliminary specifications, when finalized, are not expected to vary tremendously from the preliminary values given.
Directory of Open Access Journals (Sweden)
Arturo Jiménez-Gutiérrez
2014-08-01
Full Text Available The synthesis of water networks based on properties has commonly ignored the effect of temperature on the property balances that are part of the formulation. When wide differences of temperatures are observed within the process, such an effect might yield significant errors in the application of conventional property balances. In this work, a framework for the development of water networks that include temperature effects on property balances is presented. The approach is based on the inclusion of constants in the property operators that are commonly used to carry out the property balances. An additional term to take care of composition effects is also included. The resulting approach is embedded into a formulation based on a mixed-integer nonlinear programming model for the design of water networks. A case study is presented that shows that the proposed approach yields an improvement in the prediction of the resulting properties for the integrated network, thus affecting the optimal solution.
Tournier, Jean-Michel; El-Genk, Mohamed S.
1995-01-01
A two-dimensional Heat Pipe Transient Analysis Model, 'HPTAM,' was developed to simulate the transient operation of fully-thawed heat pipes and the startup of heat pipes from a frozen state. The model incorporates: (a) sublimation and resolidification of working fluid; (b) melting and freezing of the working fluid in the porous wick; (c) evaporation of thawed working fluid and condensation as a thin liquid film on a frozen substrate; (d) free-molecule, transition, and continuum vapor flow regimes, using the Dusty Gas Model; (e) liquid flow and heat transfer in the porous wick; and (f) thermal and hydrodynamic couplings of phases at their respective interfaces. HPTAM predicts the radius of curvature of the liquid meniscus at the liquid-vapor interface and the radial location of the working fluid level (liquid or solid) in the wick. It also includes the transverse momentum jump condition (capillary relationship of Pascal) at the liquid-vapor interface and geometrically relates the radius of curvature of the liquid meniscus to the volume fraction of vapor in the wick. The present model predicts the capillary limit and partial liquid recess (dryout) in the evaporator wick, and incorporates a liquid pooling submodel, which simulates accumulation of the excess liquid in the vapor core at the condenser end.
Ozguven, H. Nevzat
1991-01-01
A six-degree-of-freedom nonlinear semi-definite model with time varying mesh stiffness has been developed for the dynamic analysis of spur gears. The model includes a spur gear pair, two shafts, two inertias representing load and prime mover, and bearings. As the shaft and bearing dynamics have also been considered in the model, the effect of lateral-torsional vibration coupling on the dynamics of gears can be studied. In the nonlinear model developed several factors such as time varying mesh stiffness and damping, separation of teeth, backlash, single- and double-sided impacts, various gear errors and profile modifications have been considered. The dynamic response to internal excitation has been calculated by using the 'static transmission error method' developed. The software prepared (DYTEM) employs the digital simulation technique for the solution, and is capable of calculating dynamic tooth and mesh forces, dynamic factors for pinion and gear, dynamic transmission error, dynamic bearing forces and torsions of shafts. Numerical examples are given in order to demonstrate the effect of shaft and bearing dynamics on gear dynamics.
Özgüven, H. N.
1991-03-01
A six-degree-of-freedom non-linear semi-definite model with time varying mesh stiffness has been developed for the dynamic analysis of spur gears. The model includes a spur gear pair, two shafts, two inertias representing load and prime mover, and bearings. As the shaft and bearing dynamics have also been considered in the model, the effect of lateral-torsional vibration coupling on the dynamics of gears can be studied. In the non-linear model developed several factors such as time varying mesh stiffness and damping, separation of teeth, backlash, single- and double-sided impacts, various gear errors and profile modifications have been considered. The dynamic response to internal excitation has been calculated by using the "static transmission error method" developed. The software prepared (DYTEM) employs the digital simulation technique for the solution, and is capable of calculating dynamic tooth and mesh forces, dynamic factors for pinion and gear, dynamic transmission error, dynamic bearing forces and torsions of shafts. Numerical examples are given in order to demonstrate the effect of shaft and bearing dynamics on gear dynamics.
Directory of Open Access Journals (Sweden)
Mortaza Jamshidian
2005-01-01
Full Text Available The problem of simultaneous inference and multiple comparison for comparing means of k( ≥ 3 populations has been long studied in the statistics literature and is widely available in statistics literature. However to-date, the problem of multiple comparison of regression models has not found its way to the software. It is only recently that the computational aspects of this problem have been resolved in a general setting. SimReg employs this new methodology and provides users with software for multiple regression of several regression models. The comparisons can be among any set of pairs, and moreover any number of predictors can be included in the model. More importantly predictors can be constrained to their natural boundaries, if known. Computational methods for the problem of simultaneous confidence bands when predictors are constrained to intervals has also recently been addressed. SimReg utilizes this recent development to offer simultaneous confidence bands for regression models with any number of predictor variables. Again, the predictors can be constrained to their natural boundaries which results in narrower bands, as compared to the case where no restriction is imposed. A by-product of these confidence bands is a new method for comparing two regression surfaces, that is more informative than the usual partial F test.
Energy Technology Data Exchange (ETDEWEB)
Scot Martin
2013-01-31
The chemical evolution of secondary-organic-aerosol (SOA) particles and how this evolution alters their cloud-nucleating properties were studied. Simplified forms of full Koehler theory were targeted, specifically forms that contain only those aspects essential to describing the laboratory observations, because of the requirement to minimize computational burden for use in integrated climate and chemistry models. The associated data analysis and interpretation have therefore focused on model development in the framework of modified kappa-Koehler theory. Kappa is a single parameter describing effective hygroscopicity, grouping together several separate physicochemical parameters (e.g., molar volume, surface tension, and van't Hoff factor) that otherwise must be tracked and evaluated in an iterative full-Koehler equation in a large-scale model. A major finding of the project was that secondary organic materials produced by the oxidation of a range of biogenic volatile organic compounds for diverse conditions have kappa values bracketed in the range of 0.10 +/- 0.05. In these same experiments, somewhat incongruently there was significant chemical variation in the secondary organic material, especially oxidation state, as was indicated by changes in the particle mass spectra. Taken together, these findings then support the use of kappa as a simplified yet accurate general parameter to represent the CCN activation of secondary organic material in large-scale atmospheric and climate models, thereby greatly reducing the computational burden while simultaneously including the most recent mechanistic findings of laboratory studies.
Chirinda, Ngonidzashe; Olesen, Jørgen E.; Heckrath, Goswin; Paradelo Pérez, Marcos; Taghizadeh-Toosi, Arezoo
2016-04-01
Globally, soil carbon (C) reserves are second only to those in the ocean, and accounts for a significant C reservoir. In the case of arable soils, the quantity of stored C is influenced by various factors (e.g. management practices). Currently, the topography related influences on in-field soil C dynamics remain largely unknown. However, topography is known to influence a multiplicity of factors that regulate C input, storage and redistribution. To understand the patterns and untangle the complexity of soil C dynamics in arable landscapes, our study was conducted with soils from shoulderslope and footslope positions on a 7.1 ha winter wheat field in western Denmark. We first collected soil samples from shoulderslope and footslope positions with various depth intervals down to 100 cm and analyzed them for physical and chemical properties including texture and soil organic C contents. In-situ carbon dioxide (CO2) concentrations were measured at different soil profile depths at both positions for a year. Soil moisture content and temperature at 5 and 40 cm depth was measured continuously. Additionally, surface soil CO2 fluxes at shoulderslope and footslope positions were measured. We then used measurement data collected from the two landscape positions to calibrate the one-dimensional mechanistic model SOILCO2 module of the HYDRUS-1D software package and obtained soil CO2 fluxes from soil profile at two landscape positions. Furthermore, we tested whether the inclusion of vertical and lateral soil C movement improved the modeling of C dynamics in cultivated landscapes. For that, soil profile CO2 fluxes were compared with those obtained using a simple process-based soil whole profile C model, C-TOOL, which was modified to include vertical and lateral movement of C on landscape. Our results highlight the need to consider vertical and lateral soil C movement in the modeling of C dynamics in cultivated landscapes, for better qualification of net carbon storage.
Energy Technology Data Exchange (ETDEWEB)
Darcel, C. (Itasca Consultants SAS (France)); Davy, P.; Le Goc, R.; Dreuzy, J.R. de; Bour, O. (Geosciences Rennes, UMR 6118 CNRS, Univ. def Rennes, Rennes (France))
2009-11-15
the lineament scale (k{sub t} = 2) on the other, addresses the issue of the nature of the transition. We develop a new 'mechanistic' model that could help in modeling why and where this transition can occur. The transition between both regimes would occur for a fracture length of 1-10 m and even at a smaller scale for the few outcrops that follow the self-similar density model. A consequence for the disposal issue is that the model that is likely to apply in the 'blind' scale window between 10-100 m is the self-similar model as it is defined for large-scale lineaments. The self-similar model, as it is measured for some outcrops and most lineament maps, is definitely worth being investigated as a reference for scales above 1-10 m. In the rest of the report, we develop a methodology for incorporating uncertainty and variability into the DFN modeling. Fracturing properties arise from complex processes which produce an intrinsic variability; characterizing this variability as an admissible variation of model parameter or as the division of the site into subdomains with distinct DFN models is a critical point of the modeling effort. Moreover, the DFN model encompasses a part of uncertainty, due to data inherent uncertainties and sampling limits. Both effects must be quantified and incorporated into the DFN site model definition process. In that context, all available borehole data including recording of fracture intercept positions, pole orientation and relative uncertainties are used as the basis for the methodological development and further site model assessment. An elementary dataset contains a set of discrete fracture intercepts from which a parent orientation/density distribution can be computed. The elementary bricks of the site, from which these initial parent density distributions are computed, rely on the former Single Hole Interpretation division of the boreholes into sections whose local boundaries are expected to reflect - locally - geology
Ferrer, Javier; Pérez-Martín, Miguel A; Jiménez, Sara; Estrela, Teodoro; Andreu, Joaquín
2012-12-01
This paper describes two different GIS models - one stationary (GeoImpress) and the other non-stationary (Patrical) - that assess water quantity and quality in the Júcar River Basin District, a large river basin district (43,000km(2)) located in Spain. It aims to analyze the status of surface water (SW) and groundwater (GW) bodies in relation to the European Water Framework Directive (WFD) and to support measures to achieve the WFD objectives. The non-stationary model is used for quantitative analysis of water resources, including long-term water resource assessment; estimation of available GW resources; and evaluation of climate change impact on water resources. The main results obtained are the following: recent water resources have been reduced by approximately 18% compared to the reference period 1961-1990; the GW environmental volume required to accomplish the WFD objectives is approximately 30% of the GW annual resources; and the climate change impact on water resources for the short-term (2010-2040), based on a dynamic downscaling A1B scenario, implies a reduction in water resources by approximately 19% compared to 1990-2000 and a reduction of approximately 40-50% for the long-term (2070-2100), based on dynamic downscaling A2 and B2 scenarios. The model also assesses the impact of various fertilizer application scenarios on the status of future GW quality (nitrate) and if these future statuses will meet the WFD requirements. The stationary model generates data on the actual and future chemical status of SW bodies in the river basin according to the modeled scenarios and reflects the implementation of different types of measures to accomplish the Urban Waste Water Treatment Directive and the WFD. Finally, the selection and prioritization of additional measures to accomplish the WFD are based on cost-effectiveness analysis.
Accounting for baseline differences and measurement error in the analysis of change over time.
Braun, Julia; Held, Leonhard; Ledergerber, Bruno
2014-01-15
If change over time is compared in several groups, it is important to take into account baseline values so that the comparison is carried out under the same preconditions. As the observed baseline measurements are distorted by measurement error, it may not be sufficient to include them as covariate. By fitting a longitudinal mixed-effects model to all data including the baseline observations and subsequently calculating the expected change conditional on the underlying baseline value, a solution to this problem has been provided recently so that groups with the same baseline characteristics can be compared. In this article, we present an extended approach where a broader set of models can be used. Specifically, it is possible to include any desired set of interactions between the time variable and the other covariates, and also, time-dependent covariates can be included. Additionally, we extend the method to adjust for baseline measurement error of other time-varying covariates. We apply the methodology to data from the Swiss HIV Cohort Study to address the question if a joint infection with HIV-1 and hepatitis C virus leads to a slower increase of CD4 lymphocyte counts over time after the start of antiretroviral therapy.
Neumann, Rebecca B; Cardon, Zoe G; Teshera-Levye, Jennifer; Rockwell, Fulton E; Zwieniecki, Maciej A; Holbrook, N Michele
2014-04-01
The movement of water from moist to dry soil layers through the root systems of plants, referred to as hydraulic redistribution (HR), occurs throughout the world and is thought to influence carbon and water budgets and ecosystem functioning. The realized hydrologic, biogeochemical and ecological consequences of HR depend on the amount of redistributed water, whereas the ability to assess these impacts requires models that correctly capture HR magnitude and timing. Using several soil types and two ecotypes of sunflower (Helianthus annuus L.) in split-pot experiments, we examined how well the widely used HR modelling formulation developed by Ryel et al. matched experimental determination of HR across a range of water potential driving gradients. H. annuus carries out extensive night-time transpiration, and although over the last decade it has become more widely recognized that night-time transpiration occurs in multiple species and many ecosystems, the original Ryel et al. formulation does not include the effect of night-time transpiration on HR. We developed and added a representation of night-time transpiration into the formulation, and only then was the model able to capture the dynamics and magnitude of HR we observed as soils dried and night-time stomatal behaviour changed, both influencing HR.
Directory of Open Access Journals (Sweden)
Basile L. AGBA
2008-06-01
Full Text Available Mobile ad hoc networks (MANET are very difficult to design in terms of scenarios specification and propagation modeling. All these aspects must be taken into account when designing MANET. For cost-effective designing, powerful and accurate simulation tools are needed. Our first contribution in this paper is to provide a global approach process (GAP in channel modeling combining scenarios and propagation in order to have a better analysis of the physical layer, and finally to improve performances of the whole network. The GAP is implemented in an integrated simulation tool, Ad-SMPro. Moreover, channel statistics, throughput and delay are some key points to be considered when studying a mobile wireless networks. A carefully analysis of mobility effects over second order channel statistics and system performances is made based on our optimized simulation tool, Ad-SMProl. The channel is modeled by large scale fading and small scale fading including Doppler spectrum due to the double mobility of the nodes. Level Cross Rate and Average Duration of Fade are simulated as function of double mobility degree, a defined to be the ratio of the nodes' speeds. These results are compared to the theoretical predictions. We demonstrate that, in mobile ad hoc networks, flat fading channels and frequency-selective fading channels are differently affected. In addition, Bit Error rate is analysed as function of the ratio of the average bit energy to thermal noise density. Other performances (such as throughput, delay and routing traffic are analysed and conclusions related to the proposed simulation model and the mobility effects are drawn.
Lorentz symmetry and very long baseline interferometry
Le Poncin-Lafitte, C.; Hees, A.; Lambert, S.
2016-12-01
Lorentz symmetry violations can be described by an effective field theory framework that contains both general relativity and the Standard Model of particle physics called the Standard Model extension (SME). Recently, postfit analysis of Gravity Probe B and binary pulsars led to an upper limit at the 10-4 level on the time-time coefficient s¯T T of the pure-gravity sector of the minimal SME. In this work, we derive the observable of very long baseline interferometry (VLBI) in SME and then implement it into a real data analysis code of geodetic VLBI observations. Analyzing all available observations recorded since 1979, we compare estimates of s¯T T and errors obtained with various analysis schemes, including global estimations over several time spans, and with various Sun elongation cutoff angles, and by analysis of radio source coordinate time series. We obtain a constraint on s¯ T T=(-5 ±8 )×10-5 , directly fitted to the observations and improving by a factor of 5 previous postfit analysis estimates.
Lorentz symmetry and Very Long Baseline Interferometry
Poncin-Lafitte, C Le; lambert, S
2016-01-01
Lorentz symmetry violations can be described by an effective field theory framework that contains both General Relativity and the Standard Model of particle physics called the Standard-Model extension (SME). Recently, post-fit analysis of Gravity Probe B and binary pulsars lead to an upper limit at the $10^{-4}$ level on the time-time coefficient $\\bar s^{TT}$ of the pure-gravity sector of the minimal SME. In this work, we derive the observable of Very Long Baseline Interferometry (VLBI) in SME and then we implement it into a real data analysis code of geodetic VLBI observations. Analyzing all available observations recorded since 1979, we compare estimates of $\\bar s^{TT}$ and errors obtained with various analysis schemes, including global estimations over several time spans and with various Sun elongation cut-off angles, and with analysis of radio source coordinate time series. We obtain a constraint on $\\bar s^{TT}=(-5\\pm 8)\\times 10^{-5}$, directly fitted to the observations and improving by a factor 5 pr...
Todenhöfer, Tilman; Renninger, Markus; Schwentner, Christian; Stenzl, Arnulf; Gakis, Georgios
2012-12-01
Study Type - Prognosis (cohort series) Level of Evidence 2a What's known on the subject? and What does the study add? Preoperative thrombocytosis has been identified as a predictor of poor outcome in various cancer types. However, the prognostic role of platelet count in patients with invasive bladder cancer undergoing radical cystectomy is unknown. The present study demonstrates that preoperative thrombocytosis is an independent risk factor for decreased cancer-specific survival after radical treatment of invasive bladder cancer. We developed a new prognostic scoring model for cancer-specific outcomes after radical cystectomy including platelet count and established pathological risk factors. Consideration of platelet count in the final model increased its predictive accuracy significantly. Thrombocytosis may be a useful parameter to include within established international bladder cancer nomograms. • To investigate the oncological significance of preoperative thrombocytosis in patients with invasive bladder cancer undergoing radical cystectomy, as it has been reported as a marker for aggressive tumour biology in a variety of solid tumours. • The series comprised 258 patients undergoing radical cystectomy between 1999 and 2010 in whom different clinical and histopathological parameters were assessed. • Elevated platelet count was defined as >450 × 10(9) /L. • Based on regression estimates of significant parameters in multivariable analysis a new weighted scoring model was developed to predict cancer-specific outcomes. • The median follow-up was 30 months (6-116). • Of the 258 patients, 26 (10.1%) had elevated and 232 (89.9%) had normal platelet count. The 3-year cancer-specific survival in patients with normal and elevated platelet count was 61.5% and 32.7%, respectively (P thrombocytosis (2.68, 1.26-5.14; P= 0.011). • The 3-year cancer-specific survival in patients with a score 0 (low risk), 1-2 (intermediate risk) and 3
Quivira NWR biological baseline data
US Fish and Wildlife Service, Department of the Interior — This dataset is biological baseline data for Quivira National Wildlife Refuge as of January 2016. It contains data on species found on the refuge, when and where...
324 Building Baseline Radiological Characterization
Energy Technology Data Exchange (ETDEWEB)
R.J. Reeder, J.C. Cooper
2010-06-24
This report documents the analysis of radiological data collected as part of the characterization study performed in 1998. The study was performed to create a baseline of the radiological conditions in the 324 Building.
Shell-model half-lives for r-process waiting point nuclei including first-forbidden contributions
Zhi, Q; Cuenca-García, J J; Langanke, K; Martínez-Pinedo, G; Sieja, K
2013-01-01
We have performed large-scale shell-model calculations of the half-lives and neutron-branching probabilities of the r-process waiting point nuclei at the magic neutron numbers N=50, 82, and 126. The calculations include contributions from allowed Gamow-Teller and first-forbidden transitions. We find good agreement with the measured half-lives for the N=50 nuclei with charge numbers Z=28-32 and for the N=82 nuclei 129Ag and 130Cd. The contribution of forbidden transitions reduce the half-lives of the N=126 waiting point nuclei significantly, while they have only a small effect on the half-lives of the N=50 and 82 r-process nuclei.
Directory of Open Access Journals (Sweden)
Grosso Juan M.
2016-09-01
Full Text Available This paper proposes a reliability-based economic model predictive control (MPC strategy for the management of generalised flow-based networks, integrating some ideas on network service reliability, dynamic safety stock planning, and degradation of equipment health. The proposed strategy is based on a single-layer economic optimisation problem with dynamic constraints, which includes two enhancements with respect to existing approaches. The first enhancement considers chance-constraint programming to compute an optimal inventory replenishment policy based on a desired risk acceptability level, leading to dynamical allocation of safety stocks in flow-based networks to satisfy non-stationary flow demands. The second enhancement computes a smart distribution of the control effort and maximises actuators’ availability by estimating their degradation and reliability. The proposed approach is illustrated with an application of water transport networks using the Barcelona network as the case study considered.
Directory of Open Access Journals (Sweden)
Camilo Saavedra
2014-07-01
Full Text Available Single-species models have been commonly used to assess fish stocks in the past. Since these models have relatively simple data requirements, they sometimes provide the only tool available to assess the status of a stock when data are not enough to develop more complex models. However, these models have been criticized for several reasons since they provide reference points independently for each species assessed ignoring their interactions. For example, several studies suggest that even more substantial reductions in fishing mortality may be necessary to ensure MSY is reached when taking into consideration multiespecies interactions. Therefore, and as Pauly et al. (1998 stated, single-species analysis may mislead researchers and managers into neglecting the gear and trophic interactions which ultimately determine stocks long-term yields and ecosystem health. Ecosystem or multispecies models offer a number of advantages over single-species models. As stated in the workshop “Incorporating ecosystem considerations into stock assessments and management advice” (Mace, 2000 two general improvements are: a better appreciation of the fishing on ecosystem structure and function, and a better appreciation of the need to consider de value of marine ecosystems for functions other than harvesting fish. As disadvantages, multispecies models are statistically complex and include trophic relationships requiring more information (e.g. good estimations of biological parameters of each species and generally a full quantification of the diet sometimes available though the analysis of stomach contents. To reduce the number of species and therefore the amount of information needed, Minimum Realistic Models (MRMs represent an intermediate level of complexity, where only the subset of the ecosystem, important for the issue under consideration, is modeled. This approach offers the advantage of allowing a refinement of our estimates and can help answer more targeted
de Lucena, Rodrigo F.; Taioli, Fabio
2014-09-01
This paper presents a study on Rayleigh wave modeling. After model implementation using Matlab software, unpublished studies were conducted of dispersion curve sensitivity to percentage changes in parameter values, including S- and P-wave velocities, substrate density, and layer thickness. The study of the sensitivity of dispersion curves demonstrated that parameters such as S-wave velocity and layer thickness cannot be ignored as inversion parameters, while P-wave velocity and density can be considered as known parameters since their influence is minimal. However, the results showed limitations that should be considered and overcome when choosing the known and unknown parameters through determining a good initial model or/and by gathering a priori information. A methodology considering the sensitivity study of dispersion curves was developed and evaluated to generate initial values (initial model) to be included in the local search inversion algorithm, clearly establishing initial favorable conditions for data inversion.
Model of fracture for the Zry cladding of nuclear fuel rods included in the code DIONISIO 1.0
Energy Technology Data Exchange (ETDEWEB)
Soba, Alejandro [Departamento Combustibles Nucleares, Comision Nacional de Energia Atomica, Av. del Libertador 8250, 1429 Buenos Aires (Argentina)], E-mail: soba@cnea.gov.ar; Denis, Alicia [Departamento Combustibles Nucleares, Comision Nacional de Energia Atomica, Av. del Libertador 8250, 1429 Buenos Aires (Argentina)], E-mail: denis@cnea.gov.ar
2008-12-15
The DIONISIO code describes most of the main phenomena occurring in a fuel rod during normal operation of a nuclear power reactor. Starting from the irradiation history, the code predicts the temperature distribution, elastic and plastic stress and strain, creep, swelling and densification, release of fission gases, caesium and iodine to the internal rod volume, gas mixing, pressure increase, irradiation growth of the cladding, development of an oxide layer on its surface and hydrogen uptake, restructuring and grain growth in the pellet. This work presents the model of Zircaloy fracture included in the code DIONISIO 1.0. The model of pellet-cladding mechanical interaction (PCMI) provides the forces caused by the solid-solid contact which add to the changing internal pressure and to the constant external pressure. Besides, the program evaluates the effects of a corrosive atmosphere (stress corrosion cracking, SCC) internal or external. With these data, the code calculates the J integral around the tip of an initiated crack, and proceeds to analyze, according to the quantity of corrosive substance dissolved and the cladding stress field, if the crack remains unchanged, if it grows due to the I-SCC mechanism, or if propagation is ductile, following the R curve of the material. Results corresponding to different PHWR and PWR reactors are presented and compared with code results. In particular, good agreement is obtained in the simulation of MOX experiments, where the cladding failed due to propagation of cracks originated in SCC.
Hwang, H. D.; Maxit, L.; Ege, K.; Gerges, Y.; Guyader, J.-L.
2017-04-01
Vibro-acoustic simulation in the mid-frequency range is of interest for automotive and truck constructors. The dissipative treatments used for noise and vibration control such as viscoelastic patches and acoustic absorbing materials must be taken into account in the problem. The Statistical modal Energy distribution Analysis (SmEdA) model consists in extending Statistical Energy Analysis (SEA) to the mid-frequency range by establishing power balance equations between the modes of the different subsystems. The modal basis of uncoupled-subsystems that can be estimated by the finite element method in the mid-frequency range is used as input data. SmEdA was originally developed by considering constant modal damping factors for each subsystem. However, this means that it cannot describe the local distribution of dissipative materials. To overcome this issue, a methodology is proposed here to take into account the effect of these materials. This methodology is based on the finite element models of the subsystems that include well-known homogenized material models of dissipative treatments. The Galerkin method with subsystem normal modes is used to estimate the modal damping loss factors. Cross-modal coupling terms which appear in the formulation due to the dissipative materials are assumed to be negligible. An approximation of the energy sharing between the subsystems damped by dissipative materials is then described by SmEdA. The different steps of the method are validated experimentally by applying it to a laboratory test case composed of a plate-cavity system with different configurations of dissipative treatments. The comparison between the experimental and the simulation results shows good agreement in the mid-frequency range.
Energy Technology Data Exchange (ETDEWEB)
Guerrero Angulo, Jose Oscar [Universidad Autonoma de Sinaloa (Mexico); Arreguin Cortes, Felipe [Instituto Mexicano de Tecnologia del Agua, Jiutepec, Morelos (Mexico)
2002-03-01
This paper presents a hydraulic simulation model for drinking water networks, including elements that are currently not considered household connections, spatially variable flowrate distribution pipelines, and tee secondary network. This model is determined by solving the equations needed for a conventional model following an indirect procedure for the solution of large equations systems. Household connection performance is considered as dependent of water pressure and the way in which users operate the taps of such intakes. This approach allows a better a acquaintance with the drinking water supply networks performance as well as solving problems that demand a more precise hydraulic simulation, such as water quality variations, leaks in networks, and the influence of home water tanks as regulating devices. [Spanish] Se presenta un modelo de simulacion hidraulica para redes de agua potable en el cual se incluyen elementos que no se toman en cuenta actualmente, como las tomas domiciliarias, los tubos de distribucion con gastos espacialmente variado y la red secundaria, resolviendo el numero de ecuaciones que seria necesario plantear en un modelo convencional mediante un procedimiento indirecto para la solucion de grandes sistemas de ecuaciones. En las tomas domiciliarias se considera que su funcionamiento depende de las presiones y la forma en que los usuarios operan las llaves de las mismas. Este planteamiento permite conocer mejor el funcionamiento de las redes de abastecimiento de agua potable y solucionar problemas que requieren de una simulacion hidraulica mas precisa, como el comportamiento de la calidad del agua, las fugas en las redes y la influencia reguladora de los tinacos de las casas.
A post-new horizons global climate model of Pluto including the N2, CH4 and CO cycles
Forget, F.; Bertrand, T.; Vangvichith, M.; Leconte, J.; Millour, E.; Lellouch, E.
2017-05-01
We have built a new 3D Global Climate Model (GCM) to simulate Pluto as observed by New Horizons in 2015. All key processes are parametrized on the basis of theoretical equations, including atmospheric dynamics and transport, turbulence, radiative transfer, molecular conduction, as well as phases changes for N2, CH2 and CO. Pluto's climate and ice cycles are found to be very sensitive to model parameters and initial states. Nevertheless, a reference simulation is designed by running a fast, reduced version of the GCM with simplified atmospheric transport for 40,000 Earth years to initialize the surface ice distribution and sub-surface temperatures, from which a 28-Earth-year full GCM simulation is performed. Assuming a topographic depression in a Sputnik-planum (SP)-like crater on the anti-Charon hemisphere, a realistic Pluto is obtained, with most N2 and CO ices accumulated in the crater, methane frost covering both hemispheres except for the equatorial regions, and a surface pressure near 1.1 Pa in 2015 with an increase between 1988 and 2015, as reported from stellar occultations. Temperature profiles are in qualitative agreement with the observations. In particular, a cold atmospheric layer is obtained in the lowest kilometers above Sputnik Planum, as observed by New Horizons's REX experiment. It is shown to result from the combined effect of the topographic depression and N2 daytime sublimation. In the reference simulation with surface N2 ice exclusively present in Sputnik Planum, the global circulation is only forced by radiative heating gradients and remains relatively weak. Surface winds are locally induced by topography slopes and by N2 condensation and sublimation around Sputnik Planum. However, the circulation can be more intense depending on the exact distribution of surface N2 frost. This is illustrated in an alternative simulation with N2 condensing in the South Polar regions and N2 frost covering latitudes between 35°N and 48°N. A global condensation
DEFF Research Database (Denmark)
Sonne, Mads Rostgaard; Hattel, Jesper Henri
In this work, a numerical finite element model for friction stir welding of 2024-T3 aluminum alloy, consisting of a heat transfer analysis and a sequentially coupled quasi-static stress analysis is proposed. Metallurgical softening of the material is properly considered and included...
Fitzenz, D. D.; Nyst, M.; Apel, E. V.; Muir-Wood, R.
2014-12-01
The recent Canterbury earthquake sequence (CES) renewed public and academic awareness concerning the clustered nature of seismicity. Multiple event occurrence in short time and space intervals is reminiscent of aftershock sequences, but aftershock is a statistical definition, not a label one can give an earthquake in real-time. Aftershocks are defined collectively as what creates the Omori event rate decay after a large event or are defined as what is taken away as "dependent events" using a declustering method. It is noteworthy that depending on the declustering method used on the Canterbury earthquake sequence, the number of independent events varies a lot. This lack of unambiguous definition of aftershocks leads to the need to investigate the amount of clustering inherent in "declustered" risk models. This is the task we concentrate on in this contribution. We start from a background source model for the Canterbury region, in which 1) centroids of events of given magnitude are distributed using a latin-hypercube lattice, 2) following the range of preferential orientations determined from stress maps and focal mechanism, 3) with length determined using the local scaling relationship and 4) rates from a and b values derived from the declustered pre-2010 catalog. We then proceed to create tens of thousands of realizations of 6 to 20 year periods, and we define criteria to identify which successions of events in the region would be perceived as a sequence. Note that the spatial clustering expected is a lower end compared to a fully uniform distribution of events. Then we perform the same exercise with rates and b-values determined from the catalog including the CES. If the pre-2010 catalog was long (or rich) enough, then the computed "stationary" rates calculated from it would include the CES declustered events (by construction, regardless of the physical meaning of or relationship between those events). In regions of low seismicity rate (e.g., Canterbury before
Directory of Open Access Journals (Sweden)
GERMÁN LOBOS
2015-12-01
Full Text Available ABSTRACT The traditional method of net present value (NPV to analyze the economic profitability of an investment (based on a deterministic approach does not adequately represent the implicit risk associated with different but correlated input variables. Using a stochastic simulation approach for evaluating the profitability of blueberry (Vaccinium corymbosum L. production in Chile, the objective of this study is to illustrate the complexity of including risk in economic feasibility analysis when the project is subject to several but correlated risks. The results of the simulation analysis suggest that the non-inclusion of the intratemporal correlation between input variables underestimate the risk associated with investment decisions. The methodological contribution of this study illustrates the complexity of the interrelationships between uncertain variables and their impact on the convenience of carrying out this type of business in Chile. The steps for the analysis of economic viability were: First, adjusted probability distributions for stochastic input variables (SIV were simulated and validated. Second, the random values of SIV were used to calculate random values of variables such as production, revenues, costs, depreciation, taxes and net cash flows. Third, the complete stochastic model was simulated with 10,000 iterations using random values for SIV. This result gave information to estimate the probability distributions of the stochastic output variables (SOV such as the net present value, internal rate of return, value at risk, average cost of production, contribution margin and return on capital. Fourth, the complete stochastic model simulation results were used to analyze alternative scenarios and provide the results to decision makers in the form of probabilities, probability distributions, and for the SOV probabilistic forecasts. The main conclusion shown that this project is a profitable alternative investment in fruit trees in
Pires, Flávio de Oliveira; de Oliveira Pires, Flávio
2013-07-01
According to Thomas Kuhn, the scientific progress of any discipline could be distinguished by a pre-paradigm phase, a normal science phase and a revolution phase. The science advances when a scientific revolution takes place after silent period of normal science and the scientific community moves ahead to a paradigm shift. I suggest there has been a recent change of course in the direction of the exercise science. According to the 'current paradigm', exercise would be probably limited by alterations in either central command or peripheral skeletal muscles, and fatigue would be developed in a task-dependent manner. Instead, the central governor model (GCM) has proposed that all forms of exercise are centrally-regulated, the central nervous system would calculate the metabolic cost required to complete a task in order to avoid catastrophic body failure. Some have criticized the CGM and supported the traditional interpretation, but recently the scientific community appears to have begun an intellectual trajectory to accept this theory. First, the increased number of citations of articles that have supported the CGM could indicate that the community has changed the focus. Second, relevant journals have devoted special editions to promote the debate on subjects challenged by the CGM. Finally, scientists from different fields have recognized mechanisms included in the CGM to understand the exercise limits. Given the importance of the scientific community in demarcating a Kuhnian paradigm shift, I suggest that these three aspects could indicate an increased acceptance of a centrally-regulated effort model, to understand the limits of exercise.
DEFF Research Database (Denmark)
Thiessen, K.M.; Andersson, Kasper Grann; Batandjieva, B.
2009-01-01
The Urban Remediation Working Group of the International Atomic Energy Agency's EMRAS (Environmental Modelling for Radiation Safety) program was organized to address issues of remediation assessment modelling for urban areas contaminated with dispersed radionuclides. The present paper describes t...
Cardenas, Rolando; Gonzalez, Tame; Leiva, Yoelsy; Martin, Osmel; Quiros, Israel
2003-04-01
In this work we present a model of the universe in which dark energy is modeled explicitly with both a dynamical quintessence field and a cosmological constant. Our results confirm the possibility of a future collapsing universe (for a given region of the parameter space), which is necessary for a consistent formulation of both string and quantum field theories. The predictions of this model for distance modulus of supernovae are similar to those of the standard ΛCDM model.
Nguyen, Tien M.; Guillen, Andy T.; Hant, James J.; Kizer, Justin R.; Min, Inki A.; Siedlak, Dennis J. L.; Yoh, James
2017-05-01
The U.S. Air Force (USAF) has recognized the needs for owning the program and technical knowledge within the Air Force concerning the systems being acquired to ensure success. This paper extends the previous work done by the authors [1-2] on the "Resilient Program Technical Baseline Framework for Future Space Systems" and "Portfolio Decision Support Tool (PDST)" to the development and implementation of the Program and Technical Baseline (PTB) Tracking Tool (PTBTL) for the DOD acquisition life cycle. The paper describes the "simplified" PTB tracking model with a focus on the preaward phases and discusses how to implement this model in PDST.
Energy Technology Data Exchange (ETDEWEB)
Del Ben, Mauro, E-mail: delben@chem.uzh.ch; Hutter, Jürg, E-mail: hutter@chem.uzh.ch [Department of Chemistry, University of Zurich, Winterthurerstrasse 190, CH-8057 Zurich (Switzerland); VandeVondele, Joost, E-mail: joost.vandevondele@mat.ethz.ch [Department of Materials, ETH Zurich, Wolfgang-Pauli-Strasse 27, CH-8093 Zurich (Switzerland)
2015-08-07
Water is a ubiquitous liquid that displays a wide range of anomalous properties and has a delicate structure that challenges experiment and simulation alike. The various intermolecular interactions that play an important role, such as repulsion, polarization, hydrogen bonding, and van der Waals interactions, are often difficult to reproduce faithfully in atomistic models. Here, electronic structure theories including all these interactions at equal footing, which requires the inclusion of non-local electron correlation, are used to describe structure and dynamics of bulk liquid water. Isobaric-isothermal (NpT) ensemble simulations based on the Random Phase Approximation (RPA) yield excellent density (0.994 g/ml) and fair radial distribution functions, while various other density functional approximations produce scattered results (0.8-1.2 g/ml). Molecular dynamics simulation in the microcanonical (NVE) ensemble based on Møller-Plesset perturbation theory (MP2) yields dynamical properties in the condensed phase, namely, the infrared spectrum and diffusion constant. At the MP2 and RPA levels of theory, ice is correctly predicted to float on water, resolving one of the anomalies as resulting from a delicate balance between van der Waals and hydrogen bonding interactions. For several properties, obtaining quantitative agreement with experiment requires correction for nuclear quantum effects (NQEs), highlighting their importance, for structure, dynamics, and electronic properties. A computed NQE shift of 0.6 eV for the band gap and absorption spectrum illustrates the latter. Giving access to both structure and dynamics of condensed phase systems, non-local electron correlation will increasingly be used to study systems where weak interactions are of paramount importance.
Zhang, Yanyan; Pignatello, Joseph J; Tao, Shu; Xing, Baoshan
2015-03-17
Polycyclic aromatic hydrocarbons (PAHs) associated with soot or black carbon can enter the human digestive tract by unintentional ingestion of soil or other particles. This study investigated the bioaccessibility of 11 PAHs in a composite fuel soot sample using an in vitro digestive model that included silicone sheet as an absorptive sink during the small intestinal digestion stage. The sheet was meant to simulate the passive transfer of PAHs in lumen fluid across the small intestinal epithelium, which was postulated to promote desorption of labile PAHs from the soot by steepening the soot-fluid concentration gradient. We show that the presence of silicone sheet during a 4 h default digestion time significantly increased the apparent bioaccessible fraction (Bapp, %), defined as the sum in the sheet and digestive fluid relative to the total PAH determined. The ability to increase Bapp for most PAHs leveled off above a sheet-to-soot ratio of 2.0 g per 50 mg, indicating that the sheet is an effective absorptive sink and promotes desorption in the mentioned way. Enhancement of Bapp by the sheet correlated positively with the octanol-water partition coefficient (Kow), even though the partition coefficient of PAH between sheet and digestive fluid (which contains bile acid micelles) correlated negatively with Kow. It was hypothesized that PAHs initially in the soot exist in labile and nonlabile states. The fraction of labile PAH still sorbed to the soot residue after digestion, and the maximum possible (limiting) bioaccessibility (Blim) could be estimated by varying the sheet-to-soot ratio. We show conclusively that the increase in bioccessibility due to the presence of the sheet is accounted for by a corresponding decrease in fraction of labile PAH still sorbed to the soot. The Blim ranged from 30.8 to 62.4%, independent of molecular size. The nonlabile fraction of individual PAHs (69.2-37.6% in this case) is therefore large and needs to be taken into account in risk
Camera Trajectory fromWide Baseline Images
Havlena, M.; Torii, A.; Pajdla, T.
2008-09-01
Camera trajectory estimation, which is closely related to the structure from motion computation, is one of the fundamental tasks in computer vision. Reliable camera trajectory estimation plays an important role in 3D reconstruction, self localization, and object recognition. There are essential issues for a reliable camera trajectory estimation, for instance, choice of the camera and its geometric projection model, camera calibration, image feature detection and description, and robust 3D structure computation. Most of approaches rely on classical perspective cameras because of the simplicity of their projection models and ease of their calibration. However, classical perspective cameras offer only a limited field of view, and thus occlusions and sharp camera turns may cause that consecutive frames look completely different when the baseline becomes longer. This makes the image feature matching very difficult (or impossible) and the camera trajectory estimation fails under such conditions. These problems can be avoided if omnidirectional cameras, e.g. a fish-eye lens convertor, are used. The hardware which we are using in practice is a combination of Nikon FC-E9 mounted via a mechanical adaptor onto a Kyocera Finecam M410R digital camera. Nikon FC-E9 is a megapixel omnidirectional addon convertor with 180° view angle which provides images of photographic quality. Kyocera Finecam M410R delivers 2272×1704 images at 3 frames per second. The resulting combination yields a circular view of diameter 1600 pixels in the image. Since consecutive frames of the omnidirectional camera often share a common region in 3D space, the image feature matching is often feasible. On the other hand, the calibration of these cameras is non-trivial and is crucial for the accuracy of the resulting 3D reconstruction. We calibrate omnidirectional cameras off-line using the state-of-the-art technique and Mičušík's two-parameter model, that links the radius of the image point r to the
Physics Potential of Long-Baseline Experiments
Directory of Open Access Journals (Sweden)
Sanjib Kumar Agarwalla
2014-01-01
Full Text Available The discovery of neutrino mixing and oscillations over the past decade provides firm evidence for new physics beyond the Standard Model. Recently, θ13 has been determined to be moderately large, quite close to its previous upper bound. This represents a significant milestone in establishing the three-flavor oscillation picture of neutrinos. It has opened up exciting prospects for current and future long-baseline neutrino oscillation experiments towards addressing the remaining fundamental questions, in particular the type of the neutrino mass hierarchy and the possible presence of a CP-violating phase. Another recent and crucial development is the indication of non-maximal 2-3 mixing angle, causing the octant ambiguity of θ23. In this paper, I will review the phenomenology of long-baseline neutrino oscillations with a special emphasis on sub-leading three-flavor effects, which will play a crucial role in resolving these unknowns. First, I will give a brief description of neutrino oscillation phenomenon. Then, I will discuss our present global understanding of the neutrino mass-mixing parameters and will identify the major unknowns in this sector. After that, I will present the physics reach of current generation long-baseline experiments. Finally, I will conclude with a discussion on the physics capabilities of accelerator-driven possible future long-baseline precision oscillation facilities.
DEFF Research Database (Denmark)
Torto, Lorenzo; Cester, Andrea; Rizzo, Antonio
2017-01-01
We developed an improved model to fit the photocurrent density versus voltage in organic solar cells. The model has been validated by fitting data from P3HT:PCBM solar cells. Our model quantitatively accounts for the band bending near the electrodes caused by charge accumulation in the active layer....... The model explains the position of the built-in and the zero-field voltage, the value of the internal electric field, the impact of electrode materials, and the appearance of multiple inflections. In addition, the model can be used to monitor the cell condition during accelerated lifetests....
DEFF Research Database (Denmark)
Johansen, Per; Rømer, Daniel; Andersen, Torben Ole
2014-01-01
is a multibody dynamics model of a radial piston fluid power motor, which connects the rigid bodies through models of the transient hydrodynamic lubrication pressure in the joint clearance. A finite volume approach is used to model the pressure dynamics of the fluid film lubrication. The model structure......The increasing interest in hydraulic transmissions in wind and wave energy applications has created an incentive for the development of high efficiency fluid power machinery. Modeling and analysis of fluid power machinery loss mechanisms are necessary in order to accommodate this demand. At present...... fully coupled thermo-elastic models has been used to simulate and study loss mechanisms in various tribological interfaces. Consequently, a reasonable focus of further development is to couple the interface models and the rigid body mechanics of fluid power machinery. The focus of the current paper...
Baseline Removal From EMG Recordings
2007-11-02
a time-varying baseline contamination. Acknowledgements: Work funded by the Departamento de Salud del Gobierno de Navarrra and by a Spanish MEC...Name(s) and Address(es) Departamento de Ingenieria Electra y Electronica Universidad Publica de Navarra Pamplona, Spain Performing Organization Report
Lindblom, Erik; Press-Kristensen, Kåre; Vanrolleghem, Peter A; Mikkelsen, Peter S; Henze, Mogens
2009-07-01
The perspective of this work is to develop a model, which can be used to better understand and optimize wastewater treatment plants that are able to remove xenobiotic organic compounds (XOCs) in combination with removal of traditional pollutants. Results from dynamic experiments conducted with the endocrine disrupting XOC bisphenol-A (BPA) in an activated sludge process with real wastewater were used to hypothesize an ASM-based process model including aerobic growth of a specific BPA-degrading microorganism and sorption of BPA to sludge. A parameter estimation method was developed, which simultaneously utilizes steady-state background concentrations and dynamic step response data, as well as conceptual simplifications of the plant configuration. Validation results show that biodegradation of BPA is sensitive to operational conditions before and during the experiment and that the proposed model structure is capable of capturing important characteristics of the observed BPA removal, thus increasing the potential for generalizing knowledge obtained from plant specific experiments.
DEFF Research Database (Denmark)
Sunyer Pinya, Maria Antonia; Madsen, Henrik; Rosbjerg, Dan
2014-01-01
in climate model biases are negligible. This study develops a Bayesian framework that accounts for model dependencies and changes in model biases and compares it to estimates calculated based on a frequentist approach. The Bayesian framework is used to investigate the effects of the two assumptions......Climate change impact studies are subject to numerous uncertainties and assumptions. One of the main sources of uncertainty arises from the interpretation of climate model projections. Probabilistic procedures based on multimodel ensembles have been suggested in the literature to quantify...... this source of uncertainty. However, the interpretation of multimodel ensembles remains challenging. Several assumptions are often required in the uncertainty quantification of climate model projections. For example, most methods often assume that the climate models are independent and/or that changes...
Renuka V.S; Abraham T Mathew
2013-01-01
A crane system offers a typical control problem being an under actuated MIMO system. In this paper the precise modelling of a 2D gantry crane system with 3 DOF is considered. First a simple dynamic model of the system is obtained using Lagrange’s equations of motion. Then, friction non-linearities were added to the model, which were found to decrease the output magnitudes from reference values. The model was further improved by considering the possibility of 3D angular swing which showed more...
Directory of Open Access Journals (Sweden)
Elisa González-Domínguez
Full Text Available A mechanistic model for Botrytis cinerea on grapevine was developed. The model, which accounts for conidia production on various inoculum sources and for multiple infection pathways, considers two infection periods. During the first period ("inflorescences clearly visible" to "berries groat-sized", the model calculates: i infection severity on inflorescences and young clusters caused by conidia (SEV1. During the second period ("majority of berries touching" to "berries ripe for harvest", the model calculates: ii infection severity of ripening berries by conidia (SEV2; and iii severity of berry-to-berry infection caused by mycelium (SEV3. The model was validated in 21 epidemics (vineyard × year combinations between 2009 and 2014 in Italy and France. A discriminant function analysis (DFA was used to: i evaluate the ability of the model to predict mild, intermediate, and severe epidemics; and ii assess how SEV1, SEV2, and SEV3 contribute to epidemics. The model correctly classified the severity of 17 of 21 epidemics. Results from DFA were also used to calculate the daily probabilities that an ongoing epidemic would be mild, intermediate, or severe. SEV1 was the most influential variable in discriminating between mild and intermediate epidemics, whereas SEV2 and SEV3 were relevant for discriminating between intermediate and severe epidemics. The model represents an improvement of previous B. cinerea models in viticulture and could be useful for making decisions about Botrytis bunch rot control.
Energy Technology Data Exchange (ETDEWEB)
Soroudi, Alireza [Department of Electrical Engineering, Sharif University of Technology, Tehran (Iran); Ehsan, Mehdi [Department of Electrical Engineering, Sharif University of Technology, Tehran (Iran); Center of Excellence in Power System Management and Control, Sharif University of Technology, Tehran (Iran); Zareipour, Hamidreza [Department of Electrical and Computer Engineering, University of Calgary, Alberta (Canada)
2011-01-15
This paper presents a long-term dynamic multi-objective planning model for distribution network expansion along with distributed energy options. The proposed model optimizes two objectives, namely costs and emissions and determines the optimal schemes of sizing, placement and specially the dynamics (i.e., timing) of investments on distributed generation units and network reinforcements over the planning period. An efficient two-stage heuristic method is proposed to solve the formulated planning problem. The effectiveness of the proposed model is demonstrated by applying it to a distribution network and comparing the simulation results with other methods and models. (author)
Verification and optimization of the CFETR baseline scenario
Zhao, D.; Lao, L. L.; Meneghini, O.; Staebler, G. M.; Candy, J.; Smith, S. P.; Snyder, P. B.; Prater, R.; Chen, X.; Chan, V. S.; Li, J.; Chen, J.; Shi, N.; Guo, W.; Pan, C.; Jian, X.
2016-10-01
The baseline scenario of China Fusion Engineering Test Reactor (CFETR) was designed starting from 0D calculations. The CFETR baseline scenario satisfies the minimum goal of Fusion Nuclear Science Facility aimed at bridging the gaps between ITER and DEMO. 1.5D calculations are presented to verify the on-going efforts in higher-dimensional modeling of CFETR. Steady-state scenarios are calculated self-consistently by the OMFIT integrated modeling framework that includes EFIT for equilibrium, ONETWO for sources and current, TGYRO for transport. With 68MW of neutral beam power and 8MW of ECH injected to the plasma, the average ion temperature is maintained at 15keV, while 150MW fusion power is produced. The neutral beams also drive 55% of the plasma current. Modest fast ion diffusion will reduce NBCD and affect the profile substantially. Top-launch ECH will increase the current drive and the power absorption rate. EPED model are being included. Work supported by U.S. DOE under DE-FC02-04ER54698 and the USTC CFETR contract.
Revilla, Marta; Galán, Berta; Viguri, Javier R
2016-07-01
An integrated mathematical model is proposed for modelling a moving bed biofilm reactor (MBBR) for removal of chemical oxygen demand (COD) under aerobic conditions. The composite model combines the following: (i) a one-dimensional biofilm model, (ii) a bulk liquid model, and (iii) biological processes in the bulk liquid and biofilm considering the interactions among autotrophic, heterotrophic and predator microorganisms. Depending on the values for the soluble biodegradable COD loading rate (SCLR), the model takes into account a) the hydrolysis of slowly biodegradable compounds in the bulk liquid, and b) the growth of predator microorganisms in the bulk liquid and in the biofilm. The integration of the model and the SCLR allows a general description of the behaviour of COD removal by the MBBR under various conditions. The model is applied for two in-series MBBR wastewater plant from an integrated cellulose and viscose production and accurately describes the experimental concentrations of COD, total suspended solids (TSS), nitrogen and phosphorous obtained during 14 months working at different SCLRs and nutrient dosages. The representation of the microorganism group distribution in the biofilm and in the bulk liquid allow for verification of the presence of predator microorganisms in the second reactor under some operational conditions.
DEFF Research Database (Denmark)
Sonne, Mads Rostgaard; Carlone, Pierpaolo; Palazzo, Gaetano S.;
2014-01-01
In the present paper, a numerical finite element model of the precipitation hardenable AA2024-T3 aluminum alloy, consisting of a heat transfer analysis based on the Thermal Pseudo Mechanical model for heat generation, and a sequentially coupled quasi-static stress analysis is proposed. Metallurgi...
Wide baseline stereo matching based on double topological relationship consistency
Zou, Xiaohong; Liu, Bin; Song, Xiaoxue; Liu, Yang
2009-07-01
Stereo matching is one of the most important branches in computer vision. In this paper, an algorithm is proposed for wide-baseline stereo vision matching. Here, a novel scheme is presented called double topological relationship consistency (DCTR). The combination of double topological configuration includes the consistency of first topological relationship (CFTR) and the consistency of second topological relationship (CSTR). It not only sets up a more advanced model on matching, but discards mismatches by iteratively computing the fitness of the feature matches and overcomes many problems of traditional methods depending on the powerful invariance to changes in the scale, rotation or illumination across large view changes and even occlusions. Experimental examples are shown where the two cameras have been located in very different orientations. Also, epipolar geometry can be recovered using RANSAC by far the most widely method adopted possibly. By the method, we can obtain correspondences with high precision on wide baseline matching problems. Finally, the effectiveness and reliability of this method are demonstrated in wide-baseline experiments on the image pairs.
Directory of Open Access Journals (Sweden)
N. N. Belyayev
2014-05-01
Full Text Available Purpose. Chemically hazardous objects, where toxic substances are used, manufactured and stored, and also main lines, on which the hazardous materials transportation is conducted, pose potential sources of atmosphere accidental pollution.Development of the CFD model for evaluating the efficiency of the building local protection from hazardous substantives ingress by using air curtain and sorption/desorption of hazardous substance on indoor surfaces. Methodology. To solve the problem of hydrodynamic interaction of the air curtain with wind flow and considering the building influence on this process the model of ideal fluid is used. In order to calculate the transfer process of the hazardous substance in the atmosphere an equation of convection-diffusion transport of impurities is applied. To calculate the process of indoors air pollution under leaking of foul air Karisson & Huber model is used. This model takes into account the sorption of the hazardous substance at various indoors surfaces. For the numerical integration of the model equations differential methods are used. Findings. In this paper we construct an efficient CFD model of evaluating the effectiveness of the buildings protection against ingress of hazardous substances through the use of an air curtain. On the basis of the built model a computational experiment to assess the effectiveness of this protection method under varying the location of the air curtain relative to the building was carried out. Originality. A new model was developed to compute the effectiveness of the air curtain supply to reduce the toxic chemical concentration inside the building. Practical value. The developed model can be used for design of the building local protection against ingress of hazardous substances.
Directory of Open Access Journals (Sweden)
Bakalov A. N.
2013-10-01
Full Text Available One of the ways to save rare species of plants is to create models of natural communities on the grounds of the botanical gardens. In the Botanical Garden of Kuban State University we have created the model of forest communities with the participation of rare and endangered species, and we are still working on creating models of herbaceous communities. We have introduced 18 species of plants of the flora of the Krasnodar region in the forest community and more than 30 species in herbaceous community
1974-01-01
After the simplified version of the 41-Node Stolwijk Metabolic Man Model was implemented on the Sigma 3 and UNIVAC 1110 computers in batch mode, it became desirable to make certain revisions. First, the availability of time-sharing terminals makes it possible to provide the capability and flexibility of conversational interaction between user and model. Secondly, recent physiological studies show the need to revise certain parameter values contained in the model. Thirdly, it was desired to make quantitative and accurate predictions of evaporative water loss for humans in an orbiting space station. The result of the first phase of this effort are reported.
Fan, Ting-Bo; Liu, Zhen-Bo; Zhang, Zhe; Zhang, Dong; Gong, Xiu-Fen
2009-08-01
A theoretical model of the nonlinear propagation in multi-layered tissues for strong focused ultrasound is proposed. In this model, the spheroidal beam equation (SBE) is utilized to describe the nonlinear sound propagation in each layer tissue, and generalized oblique incidence theory is used to deal with the sound transmission between two layer tissues. Computer simulation is performed on a fat-muscle-liver tissue model under the irradiation of a 1 MHz focused transducer with a large aperture angle of 35°. The results demonstrate that the tissue layer would change the amplitude of sound pressure at the focal region and cause the increase of side petals.
Energy Technology Data Exchange (ETDEWEB)
Hiatt, Jessica R. [Department of Radiation Oncology, Rhode Island Hospital, The Warren Alpert Medical School of Brown University, Providence, Rhode Island 02903 (United States); Davis, Stephen D. [Department of Medical Physics, McGill University Health Centre, Montreal, Quebec H3G 1A4 (Canada); Rivard, Mark J., E-mail: mark.j.rivard@gmail.com [Department of Radiation Oncology, Tufts University School of Medicine, Boston, Massachusetts 02111 (United States)
2015-06-15
Purpose: The model S700 Axxent electronic brachytherapy source by Xoft, Inc., was characterized by Rivard et al. in 2006. Since then, the source design was modified to include a new insert at the source tip. Current study objectives were to establish an accurate source model for simulation purposes, dosimetrically characterize the new source and obtain its TG-43 brachytherapy dosimetry parameters, and determine dose differences between the original simulation model and the current model S700 source design. Methods: Design information from measurements of dissected model S700 sources and from vendor-supplied CAD drawings was used to aid establishment of an updated Monte Carlo source model, which included the complex-shaped plastic source-centering insert intended to promote water flow for cooling the source anode. These data were used to create a model for subsequent radiation transport simulations in a water phantom. Compared to the 2006 simulation geometry, the influence of volume averaging close to the source was substantially reduced. A track-length estimator was used to evaluate collision kerma as a function of radial distance and polar angle for determination of TG-43 dosimetry parameters. Results for the 50 kV source were determined every 0.1 cm from 0.3 to 15 cm and every 1° from 0° to 180°. Photon spectra in water with 0.1 keV resolution were also obtained from 0.5 to 15 cm and polar angles from 0° to 165°. Simulations were run for 10{sup 10} histories, resulting in statistical uncertainties on the transverse plane of 0.04% at r = 1 cm and 0.06% at r = 5 cm. Results: The dose-rate distribution ratio for the model S700 source as compared to the 2006 model exceeded unity by more than 5% for roughly one quarter of the solid angle surrounding the source, i.e., θ ≥ 120°. The radial dose function diminished in a similar manner as for an {sup 125}I seed, with values of 1.434, 0.636, 0.283, and 0.0975 at 0.5, 2, 5, and 10 cm, respectively. The radial dose
DEFF Research Database (Denmark)
Perers, Bengt; Kovacs, Peter; Pettersson, Ulrik
2011-01-01
An improved unglazed collector model has been validated for use in TRNSYS and IDA and also for future extension of the EN12975 collector test standard. The basic model is the same as used in the EN12975 test standard in the quasi dynamic performance test method (QDT). In this case with the addition...... of a condensation term that can handle the operation of unglazed collectors below the dew point of the air. This is very desirable for simulation of recharging of ground source energy systems and direct operation of unglazed collectors together with a heat pump. The basic idea is to have a direct connection between...... collector testing and system simulation by using the same dynamic model and parameters during testing and simulation. The model together with the parameters will be validated in each test in this way. This work describes the method applied to an unglazed collector operating partly below the dew point under...
Cardenas, R; Martin, O; Quirós, I; Cardenas, Rolando; Gonzalez, Tame; Martin, Osmel; Quiros, Israel
2003-01-01
In this work we present a model of the universe in which dark energy is modelled explicitely with both a dynamical quintessence field and a cosmological constant. Our results confirm the possibility of a collapsing universe (for a given region of the parameter space), which is necessary for an adequate definition of string theory. We have also reproduced the measurements of modulus distance from supernovae with good accuracy.
NASA Orbital Debris Baseline Populations
Krisko, Paula H.; Vavrin, A. B.
2013-01-01
The NASA Orbital Debris Program Office has created high fidelity populations of the debris environment. The populations include objects of 1 cm and larger in Low Earth Orbit through Geosynchronous Transfer Orbit. They were designed for the purpose of assisting debris researchers and sensor developers in planning and testing. This environment is derived directly from the newest ORDEM model populations which include a background derived from LEGEND, as well as specific events such as the Chinese ASAT test, the Iridium 33/Cosmos 2251 accidental collision, the RORSAT sodium-potassium droplet releases, and other miscellaneous events. It is the most realistic ODPO debris population to date. In this paper we present the populations in chart form. We describe derivations of the background population and the specific populations added on. We validate our 1 cm and larger Low Earth Orbit population against SSN, Haystack, and HAX radar measurements.
Fernández-Nieto, E D; Narbona-Reina, G; Zabsonré, J D
2015-01-01
In this work we present a deduction of the Saint-Venant-Exner model through an asymptotic analysis of the Navier-Stokes equations. A multi-scale analysis is performed in order to take into account that the velocity of the sediment layer is smaller than the one of the fluid layer. This leads us to consider a shallow water type system for the fluid layer and a lubrication Reynolds equation for the sediment one. This deduction provides some improvements with respect to the classical Saint-Venant-Exner model: (i) the deduced model has an associated energy. Moreover, it allows us to explain why classical models do not have an associated energy and how to modify them in order to recover a model with this property. (ii) The model incorporates naturally a necessary modification that must be taken into account in order to be applied to arbitrarily sloping beds. Furthermore, we show that this modification is different of the ones considered classically, and that it coincides with a classical one only if the solution ha...
Yu, Lin; McCracken, Lance M
2016-02-01
Acceptance and commitment therapy (ACT) is one of the so called "third-wave" cognitive behavioral therapies. It has been increasingly applied to chronic pain, and there is accumulating evidence to support its effectiveness. ACT is based on a model of general human functioning called the psychological flexibility (PF) model. Most facets of the PF model have been examined in chronic pain. However, a potential key facet related to "self" appears underappreciated. Indeed, a positive or healthy sense of self seems essential to our well-being, and there have been numerous studies of the self in chronic pain. At the same time, these studies are not currently well organized or easy to summarize. This lack of clarity and integration creates barriers to progress in this area of research. PF with its explicit inclusion of self-related therapeutic processes within a broad, integrative, theoretical model may help. The current review summarizes the PF model in the context of chronic pain with a specific emphasis on the parts of the model that address self-related processes.
Mode S Baseline Radar Tracking.
1982-11-01
range units and 20 azimuth units) overlaying the position of the beacon reports. In the cases analyzed where beacon reports were not radar reinforced ...82/53 j~ C ~ 7 C _ _ _ _ _ _ 4. Title end Su.btitle 5. Neget at. November 1982 MDDE S BASELINE RADAR TRACKIN4G 6. Poelin Orgeuianti.. Cede ACT-100...Ground Clutter 33 Mode S/ARTS III 100-Scan False Radar Track Summary 74 34 Percent Beacon Radar Reinforcement 77 vii INTRODUCTION PURPOSE. The purpose of
de Villiers, Marelize; Kriticos, Darren J; Veldtman, Ruan
2017-01-01
The European wasp, Vespula germanica (Fabricius) (Hymenoptera: Vespidae), is of Palaearctic origin, being native to Europe, northern Africa and Asia, and introduced into North America, Chile, Argentina, Iceland, Ascension Island, South Africa, Australia and New Zealand. Due to its polyphagous nature and scavenging behaviour, V. germanica threatens agriculture and silviculture, and negatively affects biodiversity, while its aggressive nature and venomous sting pose a health risk to humans. In areas with warmer winters and longer summers, queens and workers can survive the winter months, leading to the build-up of large nests during the following season; thereby increasing the risk posed by this species. To prevent or prepare for such unwanted impacts it is important to know where the wasp may be able to establish, either through natural spread or through introduction as a result of human transport. Distribution data from Argentina and Australia, and seasonal phenology data from Argentina were used to determine the potential distribution of V. germanica using CLIMEX modelling. In contrast to previous models, the influence of irrigation on its distribution was also investigated. Under a natural rainfall scenario, the model showed similarities to previous models. When irrigation is applied, dry stress is alleviated, leading to larger areas modelled climatically suitable compared with previous models, which provided a better fit with the actual distribution of the species. The main areas at risk of invasion by V. germanica include western USA, Mexico, small areas in Central America and in the north-western region of South America, eastern Brazil, western Russia, north-western China, Japan, the Mediterranean coastal regions of North Africa, and parts of southern and eastern Africa.
Colbert, Keegan; Naraghi, Mohammad; Boyd, James G.
2017-02-01
This paper presents a model and computational method to predict the steady-state performance of thermal flexure microactuators at high input powers and various levels of partial vacuum. The model accounts for nonlinear temperature dependence of material properties, heat loss due to radiation, and intra-device heat transfer by conduction across an air gap. The model is validated by comparing the model predictions with the experimentally measured voltage, current, and displacement at standard conditions, prior to adjusting for partial vacuum. In order to understand the effect of nonlinearities on model reliability, the predictions of six additional hypothetical models are considered where (1) intra-device heat transfer is neglected, (2) radiation is neglected, (3) the thermal conductivity of silicon is assumed to be temperature-independent, (4) the thermal conductivity of air is assumed to be temperature-independent, (5) the electrical resistivity of silicon is assumed to be linear in temperature, and (6) the thermal expansion coefficient of silicon is assumed to be temperature-independent. All factors except radiation were shown to have a significant influence on the device performance especially at high input powers. The experimentally validated full model is then employed to predict the effect of reduced air pressure on the displacement and heat transfer properties of the actuator. This aspect of the study targets applications of thermal actuators in controlled environments such as space applications, actuators used for in situ micropositioning and tensile testing inside electron microscopy chambers, or actuators incorporated into the design of MEMS resonators. It was demonstrated that the maximum actuator displacement is not a linear function of reduced pressure and that it reaches a maximum at a certain partial vacuum level.
Lauer, Wesley; Viparelli, Enrica; Piegay, Herve
2014-05-01
Sedimentary deposits adjacent to rivers can represent important sources and sinks for bed material sediment, particularly on decadal and longer timescales. The Morphodynamics and Sediment Tracers in 1-D model (MAST-1D) is a size-specific sediment transport model that allows for active exchange between channel and floodplain sediment on river reaches of tens to hundreds of kilometers in length. The model is intended to provide a mechanism for performing a first-order assessment of the likely importance of off-channel sediment exchange in controlling decadal-scale geomorphic trends, thereby helping plan and/or prioritize field data collection and higher resolution modeling work. The model develops a sediment budget for short segments of an alluvial valley. Each segment encompasses several active river bends. In each segment, a sediment transport capacity computation is performed to determine the downstream flux of bed material sediment, following the approach of most other 1-D sediment transport models. However, the model differs from most other bed evolution models in that sediment can be exchanged with the floodplain in each segment, and mass conservation is applied to both the active layer and floodplain sediment storage reservoirs. The potential for net imbalances in overall exchange as well as the size specific nature of the computations allows the model to simulate reach-scale aggradation/degradation and/or changes in bed texture. The inclusion of fine sediment in the model allows it to track geochemical tracer material and also provides a mechanism to simulate, to first order, the effects of changes in the supply of silt and clay on overall channel hydraulic capacity. The model is applied to a ~40 km reach of the Ain River, a tributary of the Rhône River in eastern France that has experienced a significant sediment deficit as a result of the construction of several dams between 1920 and 1970. MAST-1D simulations result in both incision and the formation of a
40 CFR 80.93 - Individual baseline submission and approval.
2010-07-01
...: (i) Refinery block flow diagram, showing principal refining units; (ii) Principal refining unit..., whether or not the auditor was retained through the baseline approval process. (ii) Identification of the... samples from batch processes, including volume of each batch sampled; and (G) Baseline fuel parameter...
Helbert, Guillaume; Saint-Sulpice, Luc; Arbab Chirani, Shabnam; Dieng, Lamine; Lecompte, Thibaut; Calloch, Sylvain; Pilvin, Philippe
2017-02-01
The well-known martensitic transformation is not always the unique solid-solid phase change in NiTi shape memory alloys (SMA). For this material, R-phase can occur from both austenite and martensite. In some applications, macroscopic strain of the material can be limited to 2%. In these cases, R-phase contribution can not be neglected anymore when compared with martensite. Furthermore, different thermomechanical couplings have to be taken into account to carefully predict strain rate effects and to better describe application conditions. In this paper, a new model taking into account various phase transformations with thermomechanical couplings is presented. This model is based on several transformation criteria. In most applications, SMA are used as wires, submitted to tensile-tensile loadings, in the superelasticity working range. Consequently, a uniaxial reduction of the model is presented for its simplicity. A thermodynamic framework is proposed. It enables to describe the internal variables evolution laws. The simple and fast identification process of model parameters is briefly presented. To verify the validity of the proposed model, simulation results are compared with experimental ones. The influences of testing temperature and strain amplitude on the material behavior is discussed. The damping capacity is also studied, using an energy-based criterion.
Nosedal-Sanchez, Alvaro; Jackson, Charles S.; Huerta, Gabriel
2016-07-01
A new test statistic for climate model evaluation has been developed that potentially mitigates some of the limitations that exist for observing and representing field and space dependencies of climate phenomena. Traditionally such dependencies have been ignored when climate models have been evaluated against observational data, which makes it difficult to assess whether any given model is simulating observed climate for the right reasons. The new statistic uses Gaussian Markov random fields for estimating field and space dependencies within a first-order grid point neighborhood structure. We illustrate the ability of Gaussian Markov random fields to represent empirical estimates of field and space covariances using "witch hat" graphs. We further use the new statistic to evaluate the tropical response of a climate model (CAM3.1) to changes in two parameters important to its representation of cloud and precipitation physics. Overall, the inclusion of dependency information did not alter significantly the recognition of those regions of parameter space that best approximated observations. However, there were some qualitative differences in the shape of the response surface that suggest how such a measure could affect estimates of model uncertainty.
Directory of Open Access Journals (Sweden)
E.C. Biscaia Junior
2001-06-01
Full Text Available A dynamic kinetic-diffusive model for the extraction of metallic ions from aqueous liquors using liquid surfactant membranes is proposed. The model incorporates undesirable intrinsic phenomena such as swelling and breakage of the emulsion globules that have to be controlled during process operation. These phenomena change the spatial location of the chemical reaction during the course of extraction, resulting in a transient moving boundary problem. The orthogonal collocation method was used to transform the partial differential equations into an ordinary differential equation set that was solved by an implicit numerical routine. The model was found to be numerically stable and reliable in predicting the behaviour of zinc extraction with acidic extractant for long residence times.
An Asset Pricing Approach to Testing General Term Structure Models