Integration of high-fidelity simulator in third-year paediatrics clerkship.

PubMed

Ortiz, Nerian; Pedrogo, Yasmin; Bonet, Nydia

2011-06-01

Simulation in medicine is a useful tool for assessing clinical competencies. The liaison committee on medical education expects students to have simulation experiences in the curriculum. The integration of simulators has been encouraged for clinical clerkships. The use of the human simulator in a safe environment should result in enhanced teamworking, communication and critical thinking skills. During the academic year 2007-08, a formative activity using the simulator was implemented in the paediatrics clerkship. The objectives included exposing students to an emergent general paediatric medical scenario using the human simulator. It was imperative that students would adequately go through the critical thinking process. The paediatrics clerkship has incorporated a formative activity using the high-fidelity simulator. A faculty member debriefed the students, and feedback was offered. A total of 124 students participated in the activity. Ninety-eight percent agreed that the use of the simulator in a scenario such as the one presented allowed for a better understanding of the clinical issues studied in the clerkship. More than 85 percent of the students recommended the integration of the simulator in other major clinical clerkships. Performance in the objective structured clinical exam (OSCE) at the end of the clerkship has improved after the implementation of this formative activity. The use of the high-fidelity simulator during the paediatrics clerkship has been identified as an excellent teaching tool. This formative activity has been deemed successful by the students, who feel that it serves as an extra tool to strengthen learned concepts and skills. © Blackwell Publishing Ltd 2011.

Thermal airborne multispectral aster simulator and its preliminary results

NASA Astrophysics Data System (ADS)

Mills, F.; Kannari, Y.; Watanabe, H.; Sano, M.; Chang, S. H.

1994-03-01

An Airborne ASTER Simulator (AAS) is being developed for the Japan Resources Observation System Organization (JAROS) by the Geophysical Environmental Research (GER) Corporation. The first test flights of the AAS were over Cuprite, Nevada; Long Valley, California; and Death Valley, California, in December 1991. Preliminary laboratory tests at NASA's Stennis Space Center (SSC) were completed in April 1992. The results of the these tests indicate the AAS can discriminate between silicate and non-silicate rocks. The improvements planned for the next two years may give a spectral Full-Width at Half-Maximum (FWHM) of 0.3 μm and NEΔT of 0.2 - 0.5°K. The AAS has the potential to become a good tool for airborne TIR research and can be used for simulations of future satellite-borne TIR sensors. Flight tests over Cuprite, Nevada, and Castaic Lake, California, are planned for October-December 1992.

International benchmarking of longitudinal train dynamics simulators: results

NASA Astrophysics Data System (ADS)

Wu, Qing; Spiryagin, Maksym; Cole, Colin; Chang, Chongyi; Guo, Gang; Sakalo, Alexey; Wei, Wei; Zhao, Xubao; Burgelman, Nico; Wiersma, Pier; Chollet, Hugues; Sebes, Michel; Shamdani, Amir; Melzi, Stefano; Cheli, Federico; di Gialleonardo, Egidio; Bosso, Nicola; Zampieri, Nicolò; Luo, Shihui; Wu, Honghua; Kaza, Guy-Léon

2018-03-01

This paper presents the results of the International Benchmarking of Longitudinal Train Dynamics Simulators which involved participation of nine simulators (TABLDSS, UM, CRE-LTS, TDEAS, PoliTo, TsDyn, CARS, BODYSIM and VOCO) from six countries. Longitudinal train dynamics results and computing time of four simulation cases are presented and compared. The results show that all simulators had basic agreement in simulations of locomotive forces, resistance forces and track gradients. The major differences among different simulators lie in the draft gear models. TABLDSS, UM, CRE-LTS, TDEAS, TsDyn and CARS had general agreement in terms of the in-train forces; minor differences exist as reflections of draft gear model variations. In-train force oscillations were observed in VOCO due to the introduction of wheel-rail contact. In-train force instabilities were sometimes observed in PoliTo and BODYSIM due to the velocity controlled transitional characteristics which could have generated unreasonable transitional stiffness. Regarding computing time per train operational second, the following list is in order of increasing computing speed: VOCO, TsDyn, PoliTO, CARS, BODYSIM, UM, TDEAS, CRE-LTS and TABLDSS (fastest); all simulators except VOCO, TsDyn and PoliTo achieved faster speeds than real-time simulations. Similarly, regarding computing time per integration step, the computing speeds in order are: CRE-LTS, VOCO, CARS, TsDyn, UM, TABLDSS and TDEAS (fastest).

Cassini radar : system concept and simulation results

NASA Astrophysics Data System (ADS)

Melacci, P. T.; Orosei, R.; Picardi, G.; Seu, R.

1998-10-01

The Cassini mission is an international venture, involving NASA, the European Space Agency (ESA) and the Italian Space Agency (ASI), for the investigation of the Saturn system and, in particular, Titan. The Cassini radar will be able to see through Titan's thick, optically opaque atmosphere, allowing us to better understand the composition and the morphology of its surface, but the interpretation of the results, due to the complex interplay of many different factors determining the radar echo, will not be possible without an extensive modellization of the radar system functioning and of the surface reflectivity. In this paper, a simulator of the multimode Cassini radar will be described, after a brief review of our current knowledge of Titan and a discussion of the contribution of the Cassini radar in answering to currently open questions. Finally, the results of the simulator will be discussed. The simulator has been implemented on a RISC 6000 computer by considering only the active modes of operation, that is altimeter and synthetic aperture radar. In the instrument simulation, strict reference has been made to the present planned sequence of observations and to the radar settings, including burst and single pulse duration, pulse bandwidth, pulse repetition frequency and all other parameters which may be changed, and possibly optimized, according to the operative mode. The observed surfaces are simulated by a facet model, allowing the generation of surfaces with Gaussian or non-Gaussian roughness statistic, together with the possibility of assigning to the surface an average behaviour which can represent, for instance, a flat surface or a crater. The results of the simulation will be discussed, in order to check the analytical evaluations of the models of the average received echoes and of the attainable performances. In conclusion, the simulation results should allow the validation of the theoretical evaluations of the capabilities of microwave instruments, when

The effect of year-to-year variability of leaf area index on Variable Infiltration Capacity model performance and simulation of runoff

NASA Astrophysics Data System (ADS)

Tesemma, Z. K.; Wei, Y.; Peel, M. C.; Western, A. W.

2015-09-01

This study assessed the effect of using observed monthly leaf area index (LAI) on hydrological model performance and the simulation of runoff using the Variable Infiltration Capacity (VIC) hydrological model in the Goulburn-Broken catchment of Australia, which has heterogeneous vegetation, soil and climate zones. VIC was calibrated with both observed monthly LAI and long-term mean monthly LAI, which were derived from the Global Land Surface Satellite (GLASS) leaf area index dataset covering the period from 1982 to 2012. The model performance under wet and dry climates for the two different LAI inputs was assessed using three criteria, the classical Nash-Sutcliffe efficiency, the logarithm transformed flow Nash-Sutcliffe efficiency and the percentage bias. Finally, the deviation of the simulated monthly runoff using the observed monthly LAI from simulated runoff using long-term mean monthly LAI was computed. The VIC model predicted monthly runoff in the selected sub-catchments with model efficiencies ranging from 61.5% to 95.9% during calibration (1982-1997) and 59% to 92.4% during validation (1998-2012). Our results suggest systematic improvements, from 4% to 25% in Nash-Sutcliffe efficiency, in sparsely forested sub-catchments when the VIC model was calibrated with observed monthly LAI instead of long-term mean monthly LAI. There was limited systematic improvement in tree dominated sub-catchments. The results also suggest that the model overestimation or underestimation of runoff during wet and dry periods can be reduced to 25 mm and 35 mm respectively by including the year-to-year variability of LAI in the model, thus reflecting the responses of vegetation to fluctuations in climate and other factors. Hence, the year-to-year variability in LAI should not be neglected; rather it should be included in model calibration as well as simulation of monthly water balance.

Second-Year Pharmacy Students’ Perceptions of Adhering to a Complex Simulated Medication Regimen

PubMed Central

Hamer, David; Lehotsky, Kristin

2012-01-01

Objective. To conduct a simulated medication regimen with second-year pharmacy students to determine their anticipated versus actual difficulty in adhering to it. Methods. Second-year pharmacy students were given 6 fictitious medications (jellybeans) and a drug regimen to adhere to for 6 days. Pre- and post-intervention surveys were conducted to compare participants anticipated vs. actual difficulty with adherence and changes in empathy toward patients. Results. The 69 (96%) students who participated in the study missed on average 16% of all simulated medication doses and noted that adhering to the complex medication regimen was more difficult than they had anticipated. Eighty-nine percent of students agreed or strongly agreed the project was valuable in developing empathy towards patients taking complex medication regimens. Conclusions. Pharmacy students participating in a simulated medication regimen missed a notable number of doses and reported a greater level of empathy for patients taking complex medication regiments. Finding meaningful ways to integrate adherence into the curriculum is essential. PMID:22412210

Nursing Simulation: A Review of the Past 40 Years

ERIC Educational Resources Information Center

Nehring, Wendy M.; Lashley, Felissa R.

2009-01-01

Simulation, in its many forms, has been a part of nursing education and practice for many years. The use of games, computer-assisted instruction, standardized patients, virtual reality, and low-fidelity to high-fidelity mannequins have appeared in the past 40 years, whereas anatomical models, partial task trainers, and role playing were used…

Entry, Descent and Landing Systems Analysis: Exploration Class Simulation Overview and Results

NASA Technical Reports Server (NTRS)

DwyerCianciolo, Alicia M.; Davis, Jody L.; Shidner, Jeremy D.; Powell, Richard W.

2010-01-01

NASA senior management commissioned the Entry, Descent and Landing Systems Analysis (EDL-SA) Study in 2008 to identify and roadmap the Entry, Descent and Landing (EDL) technology investments that the agency needed to make in order to successfully land large payloads at Mars for both robotic and exploration or human-scale missions. The year one exploration class mission activity considered technologies capable of delivering a 40-mt payload. This paper provides an overview of the exploration class mission study, including technologies considered, models developed and initial simulation results from the EDL-SA year one effort.

Effect of year-to-year variability of leaf area index on variable infiltration capacity model performance and simulation of streamflow during drought

NASA Astrophysics Data System (ADS)

Tesemma, Z. K.; Wei, Y.; Peel, M. C.; Western, A. W.

2014-09-01

This study assessed the effect of using observed monthly leaf area index (LAI) on hydrologic model performance and the simulation of streamflow during drought using the variable infiltration capacity (VIC) hydrological model in the Goulburn-Broken catchment of Australia, which has heterogeneous vegetation, soil and climate zones. VIC was calibrated with both observed monthly LAI and long-term mean monthly LAI, which were derived from the Global Land Surface Satellite (GLASS) observed monthly LAI dataset covering the period from 1982 to 2012. The model performance under wet and dry climates for the two different LAI inputs was assessed using three criteria, the classical Nash-Sutcliffe efficiency, the logarithm transformed flow Nash-Sutcliffe efficiency and the percentage bias. Finally, the percentage deviation of the simulated monthly streamflow using the observed monthly LAI from simulated streamflow using long-term mean monthly LAI was computed. The VIC model predicted monthly streamflow in the selected sub-catchments with model efficiencies ranging from 61.5 to 95.9% during calibration (1982-1997) and 59 to 92.4% during validation (1998-2012). Our results suggest systematic improvements from 4 to 25% in the Nash-Sutcliffe efficiency in pasture dominated catchments when the VIC model was calibrated with the observed monthly LAI instead of the long-term mean monthly LAI. There was limited systematic improvement in tree dominated catchments. The results also suggest that the model overestimation or underestimation of streamflow during wet and dry periods can be reduced to some extent by including the year-to-year variability of LAI in the model, thus reflecting the responses of vegetation to fluctuations in climate and other factors. Hence, the year-to-year variability in LAI should not be neglected; rather it should be included in model calibration as well as simulation of monthly water balance.

Exploring Space Physics Concepts Using Simulation Results

NASA Astrophysics Data System (ADS)

Gross, N. A.

2008-05-01

The Center for Integrated Space Weather Modeling (CISM), a Science and Technology Center (STC) funded by the National Science Foundation, has the goal of developing a suite of integrated physics based computer models of the space environment that can follow the evolution of a space weather event from the Sun to the Earth. In addition to the research goals, CISM is also committed to training the next generation of space weather professionals who are imbued with a system view of space weather. This view should include an understanding of both helio-spheric and geo-space phenomena. To this end, CISM offers a yearly Space Weather Summer School targeted to first year graduate students, although advanced undergraduates and space weather professionals have also attended. This summer school uses a number of innovative pedagogical techniques including devoting each afternoon to a computer lab exercise that use results from research quality simulations and visualization techniques, along with ground based and satellite data to explore concepts introduced during the morning lectures. These labs are suitable for use in wide variety educational settings from formal classroom instruction to outreach programs. The goal of this poster is to outline the goals and content of the lab materials so that instructors may evaluate their potential use in the classroom or other settings.

Constructing and Evaluating a Validity Argument for the Final-Year Ward Simulation Exercise

ERIC Educational Resources Information Center

Till, Hettie; Ker, Jean; Myford, Carol; Stirling, Kevin; Mires, Gary

2015-01-01

The authors report final-year ward simulation data from the University of Dundee Medical School. Faculty who designed this assessment intend for the final score to represent an individual senior medical student's level of clinical performance. The results are included in each student's portfolio as one source of evidence of the student's…

Presenting simulation results in a nested loop plot.

PubMed

Rücker, Gerta; Schwarzer, Guido

2014-12-12

Statisticians investigate new methods in simulations to evaluate their properties for future real data applications. Results are often presented in a number of figures, e.g., Trellis plots. We had conducted a simulation study on six statistical methods for estimating the treatment effect in binary outcome meta-analyses, where selection bias (e.g., publication bias) was suspected because of apparent funnel plot asymmetry. We varied five simulation parameters: true treatment effect, extent of selection, event proportion in control group, heterogeneity parameter, and number of studies in meta-analysis. In combination, this yielded a total number of 768 scenarios. To present all results using Trellis plots, 12 figures were needed. Choosing bias as criterion of interest, we present a 'nested loop plot', a diagram type that aims to have all simulation results in one plot. The idea was to bring all scenarios into a lexicographical order and arrange them consecutively on the horizontal axis of a plot, whereas the treatment effect estimate is presented on the vertical axis. The plot illustrates how parameters simultaneously influenced the estimate. It can be combined with a Trellis plot in a so-called hybrid plot. Nested loop plots may also be applied to other criteria such as the variance of estimation. The nested loop plot, similar to a time series graph, summarizes all information about the results of a simulation study with respect to a chosen criterion in one picture and provides a suitable alternative or an addition to Trellis plots.

Improving the result of forcasting using reservoir and surface network simulation

NASA Astrophysics Data System (ADS)

Hendri, R. S.; Winarta, J.

2018-01-01

This study was aimed to get more representative results in production forcasting using integrated simulation in pipeline gathering system of X field. There are 5 main scenarios which consist of the production forecast of the existing condition, work over, and infill drilling. Then, it’s determined the best development scenario. The methods of this study is Integrated Reservoir Simulator and Pipeline Simulator so-calle as Integrated Reservoir and Surface Network Simulation. After well data result from reservoir simulator was then integrated with pipeline networking simulator’s to construct a new schedule, which was input for all simulation procedure. The well design result was done by well modeling simulator then exported into pipeline simulator. Reservoir prediction depends on the minimum value of Tubing Head Pressure (THP) for each well, where the pressure drop on the Gathering Network is not necessary calculated. The same scenario was done also for the single-reservoir simulation. Integration Simulation produces results approaching the actual condition of the reservoir and was confirmed by the THP profile, which difference between those two methods. The difference between integrated simulation compared to single-modeling simulation is 6-9%. The aimed of solving back-pressure problem in pipeline gathering system of X field is achieved.

NREL: News - Solar Decathlon Design Presentation and Simulation Results

Science.gov Websites

Announced Design Presentation and Simulation Results Announced Monday, September 30, 2002 took first place in the Design Presentation and Simulation Contest at the Solar Village on the National Tech in third. Design Presentation and Simulation is one of ten contests in the Solar Decathlon, which

Simulated Driving Assessment (SDA) for teen drivers: results from a validation study.

PubMed

McDonald, Catherine C; Kandadai, Venk; Loeb, Helen; Seacrist, Thomas S; Lee, Yi-Ching; Winston, Zachary; Winston, Flaura K

2015-06-01

Driver error and inadequate skill are common critical reasons for novice teen driver crashes, yet few validated, standardised assessments of teen driving skills exist. The purpose of this study is to evaluate the construct and criterion validity of a newly developed Simulated Driving Assessment (SDA) for novice teen drivers. The SDA's 35 min simulated drive incorporates 22 variations of the most common teen driver crash configurations. Driving performance was compared for 21 inexperienced teens (age 16-17 years, provisional license ≤90 days) and 17 experienced adults (age 25-50 years, license ≥5 years, drove ≥100 miles per week, no collisions or moving violations ≤3 years). SDA driving performance (Error Score) was based on driving safety measures derived from simulator and eye-tracking data. Negative driving outcomes included simulated collisions or run-off-the-road incidents. A professional driving evaluator/instructor (DEI Score) reviewed videos of SDA performance. The SDA demonstrated construct validity: (1) teens had a higher Error Score than adults (30 vs. 13, p=0.02); (2) For each additional error committed, the RR of a participant's propensity for a simulated negative driving outcome increased by 8% (95% CI 1.05 to 1.10, p<0.01). The SDA-demonstrated criterion validity: Error Score was correlated with DEI Score (r=-0.66, p<0.001). This study supports the concept of validated simulated driving tests like the SDA to assess novice driver skill in complex and hazardous driving scenarios. The SDA, as a standard protocol to evaluate teen driver performance, has the potential to facilitate screening and assessment of teen driving readiness and could be used to guide targeted skill training. Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://group.bmj.com/group/rights-licensing/permissions.

LENS: μLENS Simulations, Analysis, and Results

NASA Astrophysics Data System (ADS)

Rasco, Charles

2013-04-01

Simulations of the Low-Energy Neutrino Spectrometer prototype, μLENS, have been performed in order to benchmark the first measurements of the μLENS detector at the Kimballton Underground Research Facility (KURF). μLENS is a 6x6x6 celled scintillation lattice filled with Linear Alkylbenzene based scintillator. We have performed simulations of μLENS using the GEANT4 toolkit. We have measured various radioactive sources, LEDs, and environmental background radiation measurements at KURF using up to 96 PMTs with a simplified data acquisition system of QDCs and TDCs. In this talk we will demonstrate our understanding of the light propagation and we will compare simulation results with measurements of the μLENS detector of various radioactive sources, LEDs, and the environmental background radiation.

Hyper-X Stage Separation: Simulation Development and Results

NASA Technical Reports Server (NTRS)

Reubush, David E.; Martin, John G.; Robinson, Jeffrey S.; Bose, David M.; Strovers, Brian K.

2001-01-01

This paper provides an overview of stage separation simulation development and results for NASA's Hyper-X program; a focused hypersonic technology effort designed to move hypersonic, airbreathing vehicle technology from the laboratory environment to the flight environment. This paper presents an account of the development of the current 14 degree of freedom stage separation simulation tool (SepSim) and results from use of the tool in a Monte Carlo analysis to evaluate the risk of failure for the separation event. Results from use of the tool show that there is only a very small risk of failure in the separation event.

Titan's organic chemistry: Results of simulation experiments

NASA Technical Reports Server (NTRS)

Sagan, Carl; Thompson, W. Reid; Khare, Bishun N.

1992-01-01

Recent low pressure continuous low plasma discharge simulations of the auroral electron driven organic chemistry in Titan's mesosphere are reviewed. These simulations yielded results in good accord with Voyager observations of gas phase organic species. Optical constants of the brownish solid tholins produced in similar experiments are in good accord with Voyager observations of the Titan haze. Titan tholins are rich in prebiotic organic constituents; the Huygens entry probe may shed light on some of the processes that led to the origin of life on Earth.

A two-year experience of an integrated simulation residency curriculum.

PubMed

Wittels, Kathleen A; Takayesu, James K; Nadel, Eric S

2012-07-01

Human Patient Simulation (HPS) is increasingly used in medical education, but its role in Emergency Medicine (EM) residency education is uncertain. The objective of this study was to evaluate the perceived effectiveness of HPS when fully integrated into an EM residency didactic curriculum. The study design was a cross-sectional survey performed in 2006, 2 years after the implementation of an integrated simulation curriculum. Fifty-four residents (postgraduate year [PGY] 1-4) of a 4-year EM residency were surveyed with demographic and curricular questions on the perceived value of simulation relative to other teaching formats. Survey items were rated on a bipolar linear numeric scale of 1 (strongly disagree) to 9 (strongly agree), with 5 being neutral. Data were analyzed using Student t-tests. Forty residents responded to the survey (74% response rate). The perceived effectiveness of HPS was higher for junior residents than senior residents (8.0 vs. 6.2, respectively, p<0.001). There were no differences in perceived effectiveness of lectures (7.8 vs. 7.9, respectively, p=0.1), morbidity and mortality conference (8.5 vs. 8.7, respectively, p=0.3), and trauma conference (8.4 vs. 8.8, respectively, p=0.2) between junior and senior residents. Scores for perceptions of improvement in residency training (knowledge acquisition and clinical decision-making) after the integration of HPS into the curriculum were positive for all residents. Residents' perceptions of HPS integration into an EM residency curriculum are positive for both improving knowledge acquisition and learning clinical decision-making. HPS was rated as more effective during junior years than senior years, while the perceived efficacy of more traditional educational modalities remained constant throughout residency training. Copyright © 2012. Published by Elsevier Inc.

First results of coupled IPS/NIMROD/GENRAY simulations

NASA Astrophysics Data System (ADS)

Jenkins, Thomas; Kruger, S. E.; Held, E. D.; Harvey, R. W.; Elwasif, W. R.; Schnack, D. D.

2010-11-01

The Integrated Plasma Simulator (IPS) framework, developed by the SWIM Project Team, facilitates self-consistent simulations of complicated plasma behavior via the coupling of various codes modeling different spatial/temporal scales in the plasma. Here, we apply this capability to investigate the stabilization of tearing modes by ECCD. Under IPS control, the NIMROD code (MHD) evolves fluid equations to model bulk plasma behavior, while the GENRAY code (RF) calculates the self-consistent propagation and deposition of RF power in the resulting plasma profiles. GENRAY data is then used to construct moments of the quasilinear diffusion tensor (induced by the RF) which influence the dynamics of momentum/energy evolution in NIMROD's equations. We present initial results from these coupled simulations and demonstrate that they correctly capture the physics of magnetic island stabilization [Jenkins et al, PoP 17, 012502 (2010)] in the low-beta limit. We also discuss the process of code verification in these simulations, demonstrating good agreement between NIMROD and GENRAY predictions for the flux-surface-averaged, RF-induced currents. An overview of ongoing model development (synthetic diagnostics/plasma control systems; neoclassical effects; etc.) is also presented. Funded by US DoE.

Medical Simulation Practices 2010 Survey Results

NASA Technical Reports Server (NTRS)

McCrindle, Jeffrey J.

2011-01-01

Medical Simulation Centers are an essential component of our learning infrastructure to prepare doctors and nurses for their careers. Unlike the military and aerospace simulation industry, very little has been published regarding the best practices currently in use within medical simulation centers. This survey attempts to provide insight into the current simulation practices at medical schools, hospitals, university nursing programs and community college nursing programs. Students within the MBA program at Saint Joseph's University conducted a survey of medical simulation practices during the summer 2010 semester. A total of 115 institutions responded to the survey. The survey resus discuss overall effectiveness of current simulation centers as well as the tools and techniques used to conduct the simulation activity

Comparison the Results of Numerical Simulation And Experimental Results for Amirkabir Plasma Focus Facility

NASA Astrophysics Data System (ADS)

Goudarzi, Shervin; Amrollahi, R.; Niknam Sharak, M.

2014-06-01

In this paper the results of the numerical simulation for Amirkabir Mather-type Plasma Focus Facility (16 kV, 36μF and 115 nH) in several experiments with Argon as working gas at different working conditions (different discharge voltages and gas pressures) have been presented and compared with the experimental results. Two different models have been used for simulation: five-phase model of Lee and lumped parameter model of Gonzalez. It is seen that the results (optimum pressures and current signals) of the Lee model at different working conditions show better agreement than lumped parameter model with experimental values.

Reconstructing the ideal results of a perturbed analog quantum simulator

NASA Astrophysics Data System (ADS)

Schwenk, Iris; Reiner, Jan-Michael; Zanker, Sebastian; Tian, Lin; Leppäkangas, Juha; Marthaler, Michael

2018-04-01

Well-controlled quantum systems can potentially be used as quantum simulators. However, a quantum simulator is inevitably perturbed by coupling to additional degrees of freedom. This constitutes a major roadblock to useful quantum simulations. So far there are only limited means to understand the effect of perturbation on the results of quantum simulation. Here we present a method which, in certain circumstances, allows for the reconstruction of the ideal result from measurements on a perturbed quantum simulator. We consider extracting the value of the correlator 〈Ôi(t ) Ôj(0 ) 〉 from the simulated system, where Ôi are the operators which couple the system to its environment. The ideal correlator can be straightforwardly reconstructed by using statistical knowledge of the environment, if any n -time correlator of operators Ôi of the ideal system can be written as products of two-time correlators. We give an approach to verify the validity of this assumption experimentally by additional measurements on the perturbed quantum simulator. The proposed method can allow for reliable quantum simulations with systems subjected to environmental noise without adding an overhead to the quantum system.

Simulated groundwater flow in the Ogallala and Arikaree aquifers, Rosebud Indian Reservation area, South Dakota - Revisions with data through water year 2008 and simulations of potential future scenarios

USGS Publications Warehouse

Long, Andrew J.; Putnam, Larry D.

2010-01-01

record was created, the mean of which was equal to 64 percent of the average estimated recharge rate for the 30-year calibration period. This synthetic recharge record was used to simulate the last 20 years of the calibration period under drought conditions. Compared with results of the calibrated model, decreases in hydraulic-head values for the drought scenario at the end of the simulation period were as much as 39 feet for the Ogallala aquifer. To simulate the effects of potential increases in pumping, well withdrawal rates were increased by 50 percent from those estimated for the 30-year calibration period for the last 20 years of the calibration period. Compared with results of the calibrated model, decreases in hydraulic-head values for the scenario of increased pumping at the end of the simulation period were as much as 13 feet for the Ogallala aquifer.This numerical model is suitable as a tool to help understand the flow system, to help confirm that previous estimates of aquifer properties were reasonable, and to estimate aquifer properties in areas without data. The model also is useful to help assess the effects of drought and increases in pumping by simulations of these scenarios, the results of which are not precise but may be considered when making water management decisions.

DoSSiER: Database of scientific simulation and experimental results

DOE Office of Scientific and Technical Information (OSTI.GOV)

Wenzel, Hans; Yarba, Julia; Genser, Krzystof

The Geant4, GeantV and GENIE collaborations regularly perform validation and regression tests for simulation results. DoSSiER (Database of Scientific Simulation and Experimental Results) is being developed as a central repository to store the simulation results as well as the experimental data used for validation. DoSSiER can be easily accessed via a web application. In addition, a web service allows for programmatic access to the repository to extract records in json or xml exchange formats. In this paper, we describe the functionality and the current status of various components of DoSSiER as well as the technology choices we made.

DoSSiER: Database of scientific simulation and experimental results

DOE PAGES

Wenzel, Hans; Yarba, Julia; Genser, Krzystof; ...

2016-08-01

The Geant4, GeantV and GENIE collaborations regularly perform validation and regression tests for simulation results. DoSSiER (Database of Scientific Simulation and Experimental Results) is being developed as a central repository to store the simulation results as well as the experimental data used for validation. DoSSiER can be easily accessed via a web application. In addition, a web service allows for programmatic access to the repository to extract records in json or xml exchange formats. In this paper, we describe the functionality and the current status of various components of DoSSiER as well as the technology choices we made.

Advanced Thermal Simulator Testing: Thermal Analysis and Test Results

NASA Technical Reports Server (NTRS)

Bragg-Sitton, Shannon M.; Dickens, Ricky; Dixon, David; Reid, Robert; Adams, Mike; Davis, Joe

2008-01-01

Work at the NASA Marshall Space Flight Center seeks to develop high fidelity, electrically heated thermal simulators that represent fuel elements in a nuclear reactor design to support non-nuclear testing applicable to the development of a space nuclear power or propulsion system. Comparison between the fuel pins and thermal simulators is made at the outer fuel clad surface, which corresponds to the outer sheath surface in the thermal simulator. The thermal simulators that are currently being tested correspond to a SNAP derivative reactor design that could be applied for Lunar surface power. These simulators are designed to meet the geometric and power requirements of a proposed surface power reactor design, accommodate testing of various axial power profiles, and incorporate imbedded instrumentation. This paper reports the results of thermal simulator analysis and testing in a bare element configuration, which does not incorporate active heat removal, and testing in a water-cooled calorimeter designed to mimic the heat removal that would be experienced in a reactor core.

The Serpent Strikes: Simulation in a Large First-Year Course.

ERIC Educational Resources Information Center

Schrag, Philip G.

1989-01-01

A year-long simulation of a single case supplements a traditional civil procedure course at Georgetown University. Experience with the approach suggests that design features can reduce the burdens on the instructor without reducing course effectiveness, making the approach feasible even with larger classes. (MSE)

Laboratory test results for an airborne ASTER simulator

NASA Astrophysics Data System (ADS)

Ezaka, Teruya; Kannari, Yoshiaki; Mills, Franklin P.; Watanabe, Hiroshi; Sano, Masaharu; Chang, Sheng-Huei

1993-08-01

An airborne ASTER simulator (AAS) is being developed by the Geophysical Environmental Research Corporation (GER) to study land surface temperature and emittance in the thermal infrared. Laboratory tests in October 1992 at NASA's Stennis Space Center (SSC) measured the AAS's spectral, approximate NEdT, and approximate spatial response characteristics. The spectral FWHM for most channels is smaller than 0.3 micrometers ; the NEdT for most TIR channels is better than 0.4 K; and the nominal IFOV is 5 mrad. Flight data was collected over Cuprite and Goldfield, Nevada and near Valencia, California in November 1992. The silicified and opalized zones at Cuprite could be discriminated using decorrelation-stretch images. AAS decorrelation-stretch images agree, qualitatively, with data from NASA's thermal infrared mapping spectrometer (TIMS). These results indicate the AAS may be a good tool for remote sensing studies of geological materials. Lower noise detector arrays and linear variable (optical) filters for the TIR channels will be tested in flights over Cuprite, Nevada later this year. These and other improvements may reduce the NEdT and improve the signal-to-noise ratio.

Computer simulation results of attitude estimation of earth orbiting satellites

NASA Technical Reports Server (NTRS)

Kou, S. R.

1976-01-01

Computer simulation results of attitude estimation of Earth-orbiting satellites (including Space Telescope) subjected to environmental disturbances and noises are presented. Decomposed linear recursive filter and Kalman filter were used as estimation tools. Six programs were developed for this simulation, and all were written in the basic language and were run on HP 9830A and HP 9866A computers. Simulation results show that a decomposed linear recursive filter is accurate in estimation and fast in response time. Furthermore, for higher order systems, this filter has computational advantages (i.e., less integration errors and roundoff errors) over a Kalman filter.

Microscopic Car Modeling for Intelligent Traffic and Scenario Generation in the UCF Driving Simulator : Year 2

DOT National Transportation Integrated Search

2000-01-01

A multi-year project was initiated to introduce autonomous vehicles in the University of Central Florida (UCF) Driving Simulator for real-time interaction with the simulator vehicle. This report describes the progress during the second year. In the f...

Simulation of diurnal thermal energy storage systems: Preliminary results

NASA Astrophysics Data System (ADS)

Katipamula, S.; Somasundaram, S.; Williams, H. R.

1994-12-01

This report describes the results of a simulation of thermal energy storage (TES) integrated with a simple-cycle gas turbine cogeneration system. Integrating TES with cogeneration can serve the electrical and thermal loads independently while firing all fuel in the gas turbine. The detailed engineering and economic feasibility of diurnal TES systems integrated with cogeneration systems has been described in two previous PNL reports. The objective of this study was to lay the ground work for optimization of the TES system designs using a simulation tool called TRNSYS (TRaNsient SYstem Simulation). TRNSYS is a transient simulation program with a sequential-modular structure developed at the Solar Energy Laboratory, University of Wisconsin-Madison. The two TES systems selected for the base-case simulations were: (1) a one-tank storage model to represent the oil/rock TES system; and (2) a two-tank storage model to represent the molten nitrate salt TES system. Results of the study clearly indicate that an engineering optimization of the TES system using TRNSYS is possible. The one-tank stratified oil/rock storage model described here is a good starting point for parametric studies of a TES system. Further developments to the TRNSYS library of available models (economizer, evaporator, gas turbine, etc.) are recommended so that the phase-change processes is accurately treated.

Comparison between simulations and lab results on the ASSIST test-bench

NASA Astrophysics Data System (ADS)

Le Louarn, Miska; Madec, Pierre-Yves; Kolb, Johann; Paufique, Jerome; Oberti, Sylvain; La Penna, Paolo; Arsenault, Robin

2016-07-01

We present the latest comparison results between laboratory tests carried out on the ASSIST test bench and Octopus end-to end simulations. We simulated, as closely to the lab conditions as possible, the different AOF modes (Maintenance and commissioning mode (SCAO), GRAAL (GLAO in the near IR), Galacsi Wide Field mode (GLAO in the visible) and Galacsi narrow field mode (LTAO in the visible)). We then compared the simulation results to the ones obtained on the lab bench. Several aspects were investigated, like number of corrected modes, turbulence wind speeds, LGS photon flux etc. The agreement between simulations and lab is remarkably good for all investigated parameters, giving great confidence in both simulation tool and performance of the AO system in the lab.

Numerical simulations of catastrophic disruption: Recent results

NASA Technical Reports Server (NTRS)

Benz, W.; Asphaug, E.; Ryan, E. V.

1994-01-01

Numerical simulations have been used to study high velocity two-body impacts. In this paper, a two-dimensional Largrangian finite difference hydro-code and a three-dimensional smooth particle hydro-code (SPH) are described and initial results reported. These codes can be, and have been, used to make specific predictions about particular objects in our solar system. But more significantly, they allow us to explore a broad range of collisional events. Certain parameters (size, time) can be studied only over a very restricted range within the laboratory; other parameters (initial spin, low gravity, exotic structure or composition) are difficult to study at all experimentally. The outcomes of numerical simulations lead to a more general and accurate understanding of impacts in their many forms.

Pilot study comparing simulation-based and didactic lecture-based critical care teaching for final-year medical students.

PubMed

Solymos, Orsolya; O'Kelly, Patrick; Walshe, Criona M

2015-10-21

Simulation-based medical education has rapidly evolved over the past two decades, despite this, there are few published reports of its use in critical care teaching. We hypothesised that simulation-based teaching of a critical care topic to final-year medical students is superior to lecture-based teaching. Thirty-nine final-year medical students were randomly assigned to either simulation-based or lecture-based teaching in the chosen critical care topic. The study was conducted over a 6-week period. Efficacy of each teaching method was compared through use of multiple choice questionnaires (MCQ) - baseline, post-teaching and 2 week follow-up. Student satisfaction was evaluated by means of a questionnaire. Feasibility and resource requirements were documented by teachers. Eighteen students were randomised to simulation-based, and 21 to lecture-based teaching. There were no differences in age and gender between groups (p > 0.05). Simulation proved more resource intensive requiring specialised equipment, two instructors, and increased duration of teaching sessions (126.7 min (SD = 4.71) vs 68.3 min (SD = 2.36)). Students ranked simulation-based teaching higher with regard to enjoyment (p = 0.0044), interest (p = 0.0068), relevance to taught subject (p = 0.0313), ease of understanding (p = 0.0476) and accessibility to posing questions (p = 0.001). Both groups demonstrated improvement in post-teaching MCQ from baseline (p = 0.0002), with greater improvement seen among the simulation group (p = 0.0387), however, baseline scores were higher among the lecture group. The results of the 2-week follow-up MCQ and post-teaching MCQ were not statistically significant when each modality were compared. Simulation was perceived as more enjoyable by students. Although there was a greater improvement in post-teaching MCQ among the simulator group, baseline scores were higher among lecture group which limits interpretation of efficacy

Effect of a Simulation Exercise on Restorative Identification Skills of First Year Dental Hygiene Students.

PubMed

Lemaster, Margaret; Flores, Joyce M; Blacketer, Margaret S

2016-02-01

This study explored the effectiveness of simulated mouth models to improve identification and recording of dental restorations when compared to using traditional didactic instruction combined with 2-dimensional images. Simulation has been adopted into medical and dental education curriculum to improve both student learning and patient safety outcomes. A 2-sample, independent t-test analysis of data was conducted to compare graded dental recordings of dental hygiene students using simulated mouth models and dental hygiene students using 2-dimensional photographs. Evaluations from graded dental charts were analyzed and compared between groups of students using the simulated mouth models containing random placement of custom preventive and restorative materials and traditional 2-dimensional representations of didactically described conditions. Results demonstrated a statistically significant (p≤0.0001) difference: for experimental group, students using the simulated mouth models to identify and record dental conditions had a mean of 86.73 and variance of 33.84. The control group students using traditional 2-dimensional images mean graded dental chart scores were 74.43 and variance was 14.25. Using modified simulation technology for dental charting identification may increase level of dental charting skill competency in first year dental hygiene students. Copyright © 2016 The American Dental Hygienists’ Association.

Pilgrims: A Simulation of the First Year at Plymouth Colony.

ERIC Educational Resources Information Center

Flint, Myron

This simulation allows students to learn about the struggle of daily life in Plymouth Colony. Students experience the hardships of life in the New World as they make decisions and face consequences as the Pilgrims did nearly 400 years ago. The unit is divided into nine phases with each phase taking approximately one hour of class time. Students…

Results of GEANT simulations and comparison with first experiments at DANCE.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Reifarth, R.; Bredeweg, T. A.; Browne, J. C.

2003-07-29

This report describes intensive Monte Carlo simulations carried out to be compared with the results of the first run cycle with DANCE (Detector for Advanced Neutron Capture Experiments). The experimental results were gained during the commissioning phase 2002/2003 with only a part of the array. Based on the results of these simulations the most important items to be improved before the next experiments will be addressed.

First results from simulations of supersymmetric lattices

NASA Astrophysics Data System (ADS)

Catterall, Simon

2009-01-01

We conduct the first numerical simulations of lattice theories with exact supersymmetry arising from the orbifold constructions of \\cite{Cohen:2003xe,Cohen:2003qw,Kaplan:2005ta}. We consider the Script Q = 4 theory in D = 0,2 dimensions and the Script Q = 16 theory in D = 0,2,4 dimensions. We show that the U(N) theories do not possess vacua which are stable non-perturbatively, but that this problem can be circumvented after truncation to SU(N). We measure the distribution of scalar field eigenvalues, the spectrum of the fermion operator and the phase of the Pfaffian arising after integration over the fermions. We monitor supersymmetry breaking effects by measuring a simple Ward identity. Our results indicate that simulations of Script N = 4 super Yang-Mills may be achievable in the near future.

Multiple Optical Filter Design Simulation Results

NASA Astrophysics Data System (ADS)

Mendelsohn, J.; Englund, D. C.

1986-10-01

In this paper we continue our investigation of the application of matched filters to robotic vision problems. Specifically, we are concerned with the tray-picking problem. Our principal interest in this paper is the examination of summation affects which arise from attempting to reduce the matched filter memory size by averaging of matched filters. While the implementation of matched filtering theory to applications in pattern recognition or machine vision is ideally through the use of optics and optical correlators, in this paper the results were obtained through a digital simulation of the optical process.

Simulations Build Efficacy: Empirical Results from a Four-Week Congressional Simulation

ERIC Educational Resources Information Center

Mariani, Mack; Glenn, Brian J.

2014-01-01

This article describes a four-week congressional committee simulation implemented in upper level courses on Congress and the Legislative process at two liberal arts colleges. We find that the students participating in the simulation possessed high levels of political knowledge and confidence in their political skills prior to the simulation. An…

Fast Plasma Instrument for MMS: Simulation Results

NASA Technical Reports Server (NTRS)

Figueroa-Vinas, Adolfo; Adrian, Mark L.; Lobell, James V.; Simpson, David G.; Barrie, Alex; Winkert, George E.; Yeh, Pen-Shu; Moore, Thomas E.

2008-01-01

Magnetospheric Multiscale (MMS) mission will study small-scale reconnection structures and their rapid motions from closely spaced platforms using instruments capable of high angular, energy, and time resolution measurements. The Dual Electron Spectrometer (DES) of the Fast Plasma Instrument (FPI) for MMS meets these demanding requirements by acquiring the electron velocity distribution functions (VDFs) for the full sky with high-resolution angular measurements every 30 ms. This will provide unprecedented access to electron scale dynamics within the reconnection diffusion region. The DES consists of eight half-top-hat energy analyzers. Each analyzer has a 6 deg. x 11.25 deg. Full-sky coverage is achieved by electrostatically stepping the FOV of each of the eight sensors through four discrete deflection look directions. Data compression and burst memory management will provide approximately 30 minutes of high time resolution data during each orbit of the four MMS spacecraft. Each spacecraft will intelligently downlink the data sequences that contain the greatest amount of temporal structure. Here we present the results of a simulation of the DES analyzer measurements, data compression and decompression, as well as ground-based analysis using as a seed re-processed Cluster/PEACE electron measurements. The Cluster/PEACE electron measurements have been reprocessed through virtual DES analyzers with their proper geometrical, energy, and timing scale factors and re-mapped via interpolation to the DES angular and energy phase-space sampling measurements. The results of the simulated DES measurements are analyzed and the full moments of the simulated VDFs are compared with those obtained from the Cluster/PEACE spectrometer using a standard quadrature moment, a newly implemented spectral spherical harmonic method, and a singular value decomposition method. Our preliminary moment calculations show a remarkable agreement within the uncertainties of the measurements, with the

Comparison of an empirical forest growth and yield simulator and a forest gap simulator using actual 30-year growth from two even-aged forests in Kentucky

Treesearch

Daniel A. Yaussy

2000-01-01

Two individual-tree growth simulators are used to predict the growth and mortality on a 30-year-old forest site and an 80-year-old forest site in eastern Kentucky. The empirical growth and yield model (NE-TWIGS) was developed to simulate short-term (

Analysis of the impact of simulation model simplifications on the quality of low-energy buildings simulation results

NASA Astrophysics Data System (ADS)

Klimczak, Marcin; Bojarski, Jacek; Ziembicki, Piotr; Kęskiewicz, Piotr

2017-11-01

The requirements concerning energy performance of buildings and their internal installations, particularly HVAC systems, have been growing continuously in Poland and all over the world. The existing, traditional calculation methods following from the static heat exchange model are frequently not sufficient for a reasonable heating design of a building. Both in Poland and elsewhere in the world, methods and software are employed which allow a detailed simulation of the heating and moisture conditions in a building, and also an analysis of the performance of HVAC systems within a building. However, these systems are usually difficult in use and complex. In addition, the development of a simulation model that is sufficiently adequate to the real building requires considerable time involvement of a designer, is time-consuming and laborious. A simplification of the simulation model of a building renders it possible to reduce the costs of computer simulations. The paper analyses in detail the effect of introducing a number of different variants of the simulation model developed in Design Builder on the quality of final results obtained. The objective of this analysis is to find simplifications which allow obtaining simulation results which have an acceptable level of deviations from the detailed model, thus facilitating a quick energy performance analysis of a given building.

FIVE-YEAR RESULTS OF ADJUVANT RADIOTHER

PubMed Central

Osa, Etin-Osa O.; DeWyngaert, Keith; Roses, Daniel; Speyer, James; Guth, Amber; Axelrod, Deborah; Kerimian, Maria Fenton; Goldberg, Judith D.; Formenti, Silvia C.

2015-01-01

Purpose/Objective A technique of prone breast radiotherapy delivered by a regimen of accelerated intensity modulated radiation therapy (IMRT) with a concurrent boost to the tumor bed, was developed at our institution. We report the five year results of this approach. Methods and Materials Between 2003–2006, 404 patients with Stage I–II breast cancer were prospectively enrolled into two consecutive protocols, institutional trials 03–30 and 05–181, that used the same regimen of 40.5Gy/15 fractions delivered to the index breast over 3 weeks, with a concomitant daily boost to the tumor bed of 0.5Gy (total dose=48Gy). All patients were treated after segmental mastectomy, had negative margins, and nodal assessment. Patients were set up prone: only if lung or heart volumes were in the field was a supine set-up attempted, and chosen if found to better spare these organs. Results 92% of patients were treated prone, 8% supine. 72% had stage I, 28% stage II invasive breast cancer. In-field lung volume ranged from 0 –228.27cc, mean: 19.65cc. In-field heart volume for left breast cancer patients ranged from 0–21.24cc, mean: 1.59cc. There was no heart in the field for right breast cancer patients. At a median follow-up of five years, the five-year cumulative incidence of isolated ipsilateral breast tumor recurrence was 0.82% (95% CI: 0.65–1.04). The five-year cumulative incidence of regional recurrence was 0.53% (95% CI:0.41–0.69) and the five-year overall cumulative death rate was 1.28% (95% CI: 0.48–3.38). 82% (95% CI: 77–85) of patients judged their final cosmetic result as excellent/good. Conclusions Prone accelerated IMRT with a concomitant boost results in excellent local control, optimal sparing of heart and lung, with good cosmesis. RTOG 10–05, a phase III, multi-institutional, randomized trial is ongoing and is evaluating the equivalence of a similar dose and fractionation approach to standard six weeks radiotherapy with a sequential boost. PMID

Results of a joint NOAA/NASA sounder simulation study

NASA Technical Reports Server (NTRS)

Phillips, N.; Susskind, Joel; Mcmillin, L.

1988-01-01

This paper presents the results of a joint NOAA and NASA sounder simulation study in which the accuracies of atmospheric temperature profiles and surface skin temperature measuremnents retrieved from two sounders were compared: (1) the currently used IR temperature sounder HIRS2 (High-resolution Infrared Radiation Sounder 2); and (2) the recently proposed high-spectral-resolution IR sounder AMTS (Advanced Moisture and Temperature Sounder). Simulations were conducted for both clear and partial cloud conditions. Data were analyzed at NASA using a physical inversion technique and at NOAA using a statistical technique. Results show significant improvement of AMTS compared to HIRS2 for both clear and cloudy conditions. The improvements are indicated by both methods of data analysis, but the physical retrievals outperform the statistical retrievals.

[Results of Simulation Studies

NASA Technical Reports Server (NTRS)

2003-01-01

Lattice Monte Carlo and off-lattice molecular dynamics simulations of h(sub 1)t(sub 4) and h(sub 4)t(sub l) (head/tail) amphiphile solutions have been performed as a function of surfactant concentration and temperature. The lattice and off-lattice systems exhibit quite different self-assembly behavior at equivalent thermodynamic conditions. We found that in the weakly aggregating regime (no preferred-size micelles), all models yield similar micelle size distributions at the same average aggregation number, albeit at different thermodynamic conditions (temperatures). In the strongly aggregating regime, this mapping between models (through temperature adjustment) fails, and the models exhibit qualitatively different micellization behavior. Incipient micellization in a model self-associating telechelic polymer solution results in a network with a transient elastic response that decays by a two-step relaxation: the first is due to a heterogeneous jump-diffusion process involving entrapment of end-groups within well-defined clusters and this is followed by rapid diffusion to neighboring clusters and a decay (terminal relaxation) due to cluster disintegration. The viscoelastic response of the solution manifests characteristics of a glass transition and entangled polymer network.

Challenges of forest landscape modeling - simulating large landscapes and validating results

Treesearch

Hong S. He; Jian Yang; Stephen R. Shifley; Frank R. Thompson

2011-01-01

Over the last 20 years, we have seen a rapid development in the field of forest landscape modeling, fueled by both technological and theoretical advances. Two fundamental challenges have persisted since the inception of FLMs: (1) balancing realistic simulation of ecological processes at broad spatial and temporal scales with computing capacity, and (2) validating...

Telemonitoring in Cystic Fibrosis: A 4-year Assessment and Simulation for the Next 6 Years.

PubMed

Tagliente, Irene; Trieste, Leopoldo; Solvoll, Terje; Murgia, Fabrizio; Bella, Sergio

2016-05-03

Innovative technologies and informatics offer a wide range of services to health districts, doctors, nurses, and patients, and is changing the traditional concept of health care. In the last few years, the availability of portable devices, their easiness to transport and use, and the capability to collect and transmit various clinical data have resulted in the fast development of telemedicine. However, despite its potential impact in improving patient conditions, and its cost effectiveness reported in literature, telemedicine is not in daily practice. The aim of this study is to provide evidence of the positive impact of telemonitoring proving the sustainability of an application by sending spirometry outcomes from patients' homes to the hospital doctors via the Internet, and from doctors to patients by an additional phone call solution. We examined collected data related to clinical improvement of patients with cystic fibrosis (CF). The patients were followed-up at home using telemonitoring for a period of 10 years, with the aims to prove the sustainability of the methodology (transmissions of spirometry from the patients' home to the doctors and feedback from the doctors to the patients by phone call from the hospital). We stored and analyzed all spirometry transmissions received, and tested the possible presence to decrease the costs between the standard clinical trial (only ambulatory visits) and standard clinical trial with telemonitoring for the follow-up of patients with CF (telemedicine). This was done through an economic analysis of the costs for patients followed at home by telemonitoring. We assessed four years of observation and a simulation of total long-term costs between 2010 and 2020. We discovered a potential saving of €40,397.00 per patient for 10 years, actualized at €36,802.97 for the follow-up of all patients enrolled. The results from the study suggest that telemedicine can improve the health of patients with CF. It is a relatively cheap

Petascale Kinetic Simulations in Space Sciences: New Simulations and Data Discovery Techniques and Physics Results

NASA Astrophysics Data System (ADS)

Karimabadi, Homa

2012-03-01

Recent advances in simulation technology and hardware are enabling breakthrough science where many longstanding problems can now be addressed for the first time. In this talk, we focus on kinetic simulations of the Earth's magnetosphere and magnetic reconnection process which is the key mechanism that breaks the protective shield of the Earth's dipole field, allowing the solar wind to enter the Earth's magnetosphere. This leads to the so-called space weather where storms on the Sun can affect space-borne and ground-based technological systems on Earth. The talk will consist of three parts: (a) overview of a new multi-scale simulation technique where each computational grid is updated based on its own unique timestep, (b) Presentation of a new approach to data analysis that we refer to as Physics Mining which entails combining data mining and computer vision algorithms with scientific visualization to extract physics from the resulting massive data sets. (c) Presentation of several recent discoveries in studies of space plasmas including the role of vortex formation and resulting turbulence in magnetized plasmas.

Organizational results : annual report, fiscal year 2010.

DOT National Transportation Integrated Search

2010-01-01

What can you do in five years? Pay off a car? Send your kid to college? How about change an : organizations culture? Over the past five years thats what Organizational Results has attempted to do. : By placing business process experts and resea...

Boot cAMP: educational outcomes after 4 successive years of preparatory simulation-based training at onset of internship.

PubMed

Fernandez, Gladys L; Page, David W; Coe, Nicholas P; Lee, Patrick C; Patterson, Lisa A; Skylizard, Loki; St Louis, Myron; Amaral, Marisa H; Wait, Richard B; Seymour, Neal E

2012-01-01

Preparatory training for new trainees beginning residency has been used by a variety of programs across the country. To improve the clinical orientation process for our new postgraduate year (PGY)-1 residents, we developed an intensive preparatory training curriculum inclusive of cognitive and procedural skills, training activities considered essential for early PGY-1 clinical management. We define our surgical PGY-1 Boot Camp as preparatory simulation-based training implemented at the onset of internship for introduction of skills necessary for basic surgical patient problem assessment and management. This orientation process includes exposure to simulated patient care encounters and technical skills training essential to new resident education. We report educational results of 4 successive years of Boot Camp training. Results were analyzed to determine if performance evidenced at onset of training was predictive of later educational outcomes. Learners were PGY-1 residents, in both categorical and preliminary positions, at our medium-sized surgical residency program. Over a 4-year period, from July 2007 to July 2010, all 30 PGY-1 residents starting surgical residency at our institution underwent specific preparatory didactic and skills training over a 9-week period. This consisted of mandatory weekly 1-hour and 3-hour sessions in the Simulation Center, representing a 4-fold increase in time in simulation laboratory training compared with the remainder of the year. Training occurred in 8 procedural skills areas (instrument use, knot-tying, suturing, laparoscopic skills, airway management, cardiopulmonary resuscitation, central venous catheter, and chest tube insertion) and in simulated patient care (shock, surgical emergencies, and respiratory, cardiac, and trauma management) using a variety of high- and low-tech simulation platforms. Faculty and senior residents served as instructors. All educational activities were structured to include preparatory materials

A method for data handling numerical results in parallel OpenFOAM simulations

DOE Office of Scientific and Technical Information (OSTI.GOV)

Anton, Alin; Muntean, Sebastian

Parallel computational fluid dynamics simulations produce vast amount of numerical result data. This paper introduces a method for reducing the size of the data by replaying the interprocessor traffic. The results are recovered only in certain regions of interest configured by the user. A known test case is used for several mesh partitioning scenarios using the OpenFOAM toolkit{sup ®}[1]. The space savings obtained with classic algorithms remain constant for more than 60 Gb of floating point data. Our method is most efficient on large simulation meshes and is much better suited for compressing large scale simulation results than the regular algorithms.

Electron-cloud updated simulation results for the PSR, and recent results for the SNS

NASA Astrophysics Data System (ADS)

Pivi, M.; Furman, M. A.

2002-05-01

Recent simulation results for the main features of the electron cloud in the storage ring of the Spallation Neutron Source (SNS) at Oak Ridge, and updated results for the Proton Storage Ring (PSR) at Los Alamos are presented in this paper. A refined model for the secondary emission process including the so called true secondary, rediffused and backscattered electrons has recently been included in the electron-cloud code.

Controlled cooling technology for bar and rod mills -- Computer simulation and operational results

DOE Office of Scientific and Technical Information (OSTI.GOV)

Mauk, P.J.; Kruse, M.; Plociennik, U.

The Controlled Cooling Technology (CCT) developed by SMS to simulate the rolling process and automatic control of the water cooling sections is presented. The Controlled Rolling and Cooling Technology (CRCT) model is a key part of the CCT system. It is used to simulate temperature management for the rolling stock on the computer before the actual rolling process takes place. This makes it possible to dispense with extensive rolling tests in the early stages of project planning and to greatly reduce the extent of such tests prior to the start of commercial production in a rolling mill. The CRCT modelmore » has been in use at Von Moos Stahl Ag for three years. It demonstrates that, by targeted improvement of the set-up values in both the technology and the plant, it is possible to improve microstructure quality and achieve better geometrical parameters in the rolled products. Also, the results gained with the CCT system in practical operation at the Kia Steel Bar Mill, Kunsan, Korea, are presented.« less

Observed and simulated hydrologic response for a first-order catchment during extreme rainfall 3 years after wildfire disturbance

USGS Publications Warehouse

Ebel, Brian A.; Rengers, Francis K.; Tucker, Gregory E.

2016-01-01

Hydrologic response to extreme rainfall in disturbed landscapes is poorly understood because of the paucity of measurements. A unique opportunity presented itself when extreme rainfall in September 2013 fell on a headwater catchment (i.e., <1 ha) in Colorado, USA that had previously been burned by a wildfire in 2010. We compared measurements of soil-hydraulic properties, soil saturation from subsurface sensors, and estimated peak runoff during the extreme rainfall with numerical simulations of runoff generation and subsurface hydrologic response during this event. The simulations were used to explore differences in runoff generation between the wildfire-affected headwater catchment, a simulated unburned case, and for uniform versus spatially variable parameterizations of soil-hydraulic properties that affect infiltration and runoff generation in burned landscapes. Despite 3 years of elapsed time since the 2010 wildfire, observations and simulations pointed to substantial surface runoff generation in the wildfire-affected headwater catchment by the infiltration-excess mechanism while no surface runoff was generated in the unburned case. The surface runoff generation was the result of incomplete recovery of soil-hydraulic properties in the burned area, suggesting recovery takes longer than 3 years. Moreover, spatially variable soil-hydraulic property parameterizations produced longer duration but lower peak-flow infiltration-excess runoff, compared to uniform parameterization, which may have important hillslope sediment export and geomorphologic implications during long duration, extreme rainfall. The majority of the simulated surface runoff in the spatially variable cases came from connected near-channel contributing areas, which was a substantially smaller contributing area than the uniform simulations.

Experimental and simulational result multipactors in 112 MHz QWR injector

DOE Office of Scientific and Technical Information (OSTI.GOV)

Xin, T.; Ben-Zvi, I.; Belomestnykh, S.

2015-05-03

The first RF commissioning of 112 MHz QWR superconducting electron gun was done in late 2014. The coaxial Fundamental Power Coupler (FPC) and Cathode Stalk (stalk) were installed and tested for the first time. During this experiment, we observed several multipacting barriers at different gun voltage levels. The simulation work was done within the same range. The comparison between the experimental observation and the simulation results are presented in this paper. The observations during the test are consisted with the simulation predictions. We were able to overcome most of the multipacting barriers and reach 1.8 MV gun voltage under pulsedmore » mode after several round of conditioning processes.« less

Development of 1-year-old computational phantom and calculation of organ doses during CT scans using Monte Carlo simulation.

PubMed

Pan, Yuxi; Qiu, Rui; Gao, Linfeng; Ge, Chaoyong; Zheng, Junzheng; Xie, Wenzhang; Li, Junli

2014-09-21

With the rapidly growing number of CT examinations, the consequential radiation risk has aroused more and more attention. The average dose in each organ during CT scans can only be obtained by using Monte Carlo simulation with computational phantoms. Since children tend to have higher radiation sensitivity than adults, the radiation dose of pediatric CT examinations requires special attention and needs to be assessed accurately. So far, studies on organ doses from CT exposures for pediatric patients are still limited. In this work, a 1-year-old computational phantom was constructed. The body contour was obtained from the CT images of a 1-year-old physical phantom and the internal organs were deformed from an existing Chinese reference adult phantom. To ensure the organ locations in the 1-year-old computational phantom were consistent with those of the physical phantom, the organ locations in 1-year-old computational phantom were manually adjusted one by one, and the organ masses were adjusted to the corresponding Chinese reference values. Moreover, a CT scanner model was developed using the Monte Carlo technique and the 1-year-old computational phantom was applied to estimate organ doses derived from simulated CT exposures. As a result, a database including doses to 36 organs and tissues from 47 single axial scans was built. It has been verified by calculation that doses of axial scans are close to those of helical scans; therefore, this database could be applied to helical scans as well. Organ doses were calculated using the database and compared with those obtained from the measurements made in the physical phantom for helical scans. The differences between simulation and measurement were less than 25% for all organs. The result shows that the 1-year-old phantom developed in this work can be used to calculate organ doses in CT exposures, and the dose database provides a method for the estimation of 1-year-old patient doses in a variety of CT examinations.

Development of 1-year-old computational phantom and calculation of organ doses during CT scans using Monte Carlo simulation

NASA Astrophysics Data System (ADS)

Pan, Yuxi; Qiu, Rui; Gao, Linfeng; Ge, Chaoyong; Zheng, Junzheng; Xie, Wenzhang; Li, Junli

2014-09-01

With the rapidly growing number of CT examinations, the consequential radiation risk has aroused more and more attention. The average dose in each organ during CT scans can only be obtained by using Monte Carlo simulation with computational phantoms. Since children tend to have higher radiation sensitivity than adults, the radiation dose of pediatric CT examinations requires special attention and needs to be assessed accurately. So far, studies on organ doses from CT exposures for pediatric patients are still limited. In this work, a 1-year-old computational phantom was constructed. The body contour was obtained from the CT images of a 1-year-old physical phantom and the internal organs were deformed from an existing Chinese reference adult phantom. To ensure the organ locations in the 1-year-old computational phantom were consistent with those of the physical phantom, the organ locations in 1-year-old computational phantom were manually adjusted one by one, and the organ masses were adjusted to the corresponding Chinese reference values. Moreover, a CT scanner model was developed using the Monte Carlo technique and the 1-year-old computational phantom was applied to estimate organ doses derived from simulated CT exposures. As a result, a database including doses to 36 organs and tissues from 47 single axial scans was built. It has been verified by calculation that doses of axial scans are close to those of helical scans; therefore, this database could be applied to helical scans as well. Organ doses were calculated using the database and compared with those obtained from the measurements made in the physical phantom for helical scans. The differences between simulation and measurement were less than 25% for all organs. The result shows that the 1-year-old phantom developed in this work can be used to calculate organ doses in CT exposures, and the dose database provides a method for the estimation of 1-year-old patient doses in a variety of CT examinations.

Simulation results of corkscrew motion in DARHT-II

DOE Office of Scientific and Technical Information (OSTI.GOV)

Chan, K. D.; Ekdahl, C. A.; Chen, Y. J.

2003-01-01

DARHT-II, the second axis of the Dual-Axis Radiographic Hydrodynamics Test Facility, is being commissioned. DARHT-II is a linear induction accelerator producing 2-microsecond electron beam pulses at 20 MeV and 2 kA. These 2-microsecond pulses will be chopped into four short pulses to produce time resolved x-ray images. Radiographic application requires the DARHT-II beam to have excellent beam quality, and it is important to study various beam effects that may cause quality degradation of a DARHT-II beam. One of the beam dynamic effects under study is 'corkscrew' motion. For corkscrew motion, the beam centroid is deflected off axis due to misalignmentsmore » of the solenoid magnets. The deflection depends on the beam energy variation, which is expected to vary by {+-}0.5% during the 'flat-top' part of a beam pulse. Such chromatic aberration will result in broadening of beam spot size. In this paper, we will report simulation results of our study of corkscrew motion in DARHT-II. Sensitivities of beam spot size to various accelerator parameters and the strategy for minimizing corkscrew motion will be described. Measured magnet misalignment is used in the simulation.« less

Simulation of pesticide dissipation in soil at the catchment scale over 23 years

NASA Astrophysics Data System (ADS)

Queyrel, Wilfried; Florence, Habets; Hélène, Blanchoud; Céline, Schott; Laurine, Nicola

2014-05-01

Pesticide applications lead to contamination risks of environmental compartments causing harmful effects on water resource used for drinking water. Pesticide fate modeling is assumed to be a relevant approach to study pesticide dissipation at the catchment scale. Simulations of five herbicides (atrazine, simazine, isoproturon, chlortoluron, metolachor) and one metabolite (DEA) were carried out with the crop model STICS over a 23-year period (1990-2012). The model application was performed using real agricultural practices over a small rural catchment (104 km²) located at 60km east from Paris (France). Model applications were established for two crops: wheat and maize. The objectives of the study were i) to highlight the main processes implied in pesticide fate and transfer at long-term; ii) to assess the influence of dynamics of the remaining mass of pesticide in soil on transfer; iii) to determine the most sensitive parameters related to pesticide losses by leaching over a 23-year period. The simulated data related to crop yield, water transfer, nitrates and pesticide concentrations were first compared to observations over the 23-year period, when measurements were available at the catchment scale. Then, the evaluation of the main processes related to pesticide fate and transfer was performed using long-term simulations at a yearly time step and monthly average variations. Analyses of the monthly average variations were oriented on the impact of pesticide application, water transfer and pesticide transformation on pesticide leaching. The evolution of the remaining mass of pesticide in soil, including the mobile phase (the liquid phase) and non-mobile (adsorbed at equilibrium and non-equilibrium), was studied to evaluate the impact of pesticide stored in soil on the fraction available for leaching. Finally, a sensitivity test was performed to evaluate the more sensitive parameters regarding the remaining mass of pesticide in soil and leaching. The findings of the

Development of Experimental Icing Simulation Capability for Full-Scale Swept Wings: Hybrid Design Process, Years 1 and 2

NASA Technical Reports Server (NTRS)

Fujiwara, Gustavo; Bragg, Mike; Triphahn, Chris; Wiberg, Brock; Woodard, Brian; Loth, Eric; Malone, Adam; Paul, Bernard; Pitera, David; Wilcox, Pete;

Three-Dimensional Imaging in Rhinoplasty: A Comparison of the Simulated versus Actual Result.

PubMed

Persing, Sarah; Timberlake, Andrew; Madari, Sarika; Steinbacher, Derek

2018-05-22

Computer imaging has become increasingly popular for rhinoplasty. Three-dimensional (3D) analysis permits a more comprehensive view from multiple vantage points. However, the predictability and concordance between the simulated and actual result have not been morphometrically studied. The purpose of this study was to aesthetically and quantitatively compare the simulated to actual rhinoplasty result. A retrospective review of 3D images (VECTRA, Canfield) for rhinoplasty patients was performed. Images (preop, simulated, and actual) were randomized. A blinded panel of physicians rated the images (1 = poor, 5 = excellent). The image series considered "best" was also recorded. A quantitative assessment of nasolabial angle and tip projection was compared. Paired and two-sample t tests were performed for statistical analysis (P < 0.05 as significant). Forty patients were included. 67.5% of preoperative images were rated as poor (mean = 1.7). The simulation received a mean score of 2.9 (good in 60% of cases). 82.5% of actual cases were rated good to excellent (mean 3.4) (P < 0.001). Overall, the panel significantly preferred the actual postoperative result in 77.5% of cases compared to the simulation in 22.5% of cases (P < 0.001). The actual nasal tip was more projected compared to the simulations for both males and females. There was no significant difference in nasal tip rotation between simulated and postoperative groups. 3D simulation is a powerful communication and planning tool in rhinoplasty. In this study, the actual result was deemed more aesthetic than the simulated image. Surgeon experience is important to translate the plan and achieve favorable postoperative results. This journal requires that authors assign a level of evidence to each article. For a full description of these Evidence-Based Medicine ratings, please refer to the Table of Contents or the online Instructions to Authors www.springer.com/00266 .

Interactive visualization of numerical simulation results: A tool for mission planning and data analysis

NASA Technical Reports Server (NTRS)

Berchem, J.; Raeder, J.; Walker, R. J.; Ashour-Abdalla, M.

1995-01-01

We report on the development of an interactive system for visualizing and analyzing numerical simulation results. This system is based on visualization modules which use the Application Visualization System (AVS) and the NCAR graphics packages. Examples from recent simulations are presented to illustrate how these modules can be used for displaying and manipulating simulation results to facilitate their comparison with phenomenological model results and observations.

INTEGRATING MESO-AND MICRO-SIMULATION MODELS TO EVALUATE TRAFFIC MANAGEMENT STRATEGIES, YEAR 2

DOT National Transportation Integrated Search

2017-07-04

In the Year 1 Report, the Arizona State University (ASU) Project Team described the development of a hierarchical multi-resolution simulation platform to test proactive traffic management strategies. The scope was to integrate an easily available mic...

Urology Residents' Experience and Attitude Toward Surgical Simulation: Presenting our 4-Year Experience With a Multi-institutional, Multi-modality Simulation Model.

PubMed

Chow, Alexander K; Sherer, Benjamin A; Yura, Emily; Kielb, Stephanie; Kocjancic, Ervin; Eggener, Scott; Turk, Thomas; Park, Sangtae; Psutka, Sarah; Abern, Michael; Latchamsetty, Kalyan C; Coogan, Christopher L

2017-11-01

To evaluate the Urological resident's attitude and experience with surgical simulation in residency education using a multi-institutional, multi-modality model. Residents from 6 area urology training programs rotated through simulation stations in 4 consecutive sessions from 2014 to 2017. Workshops included GreenLight photovaporization of the prostate, ureteroscopic stone extraction, laparoscopic peg transfer, 3-dimensional laparoscopy rope pass, transobturator sling placement, intravesical injection, high definition video system trainer, vasectomy, and Urolift. Faculty members provided teaching assistance, objective scoring, and verbal feedback. Participants completed a nonvalidated questionnaire evaluating utility of the workshop and soliciting suggestions for improvement. Sixty-three of 75 participants (84%) (postgraduate years 1-6) completed the exit questionnaire. Median rating of exercise usefulness on a scale of 1-10 ranged from 7.5 to 9. On a scale of 0-10, cumulative median scores of the course remained high over 4 years: time limit per station (9; interquartile range [IQR] 2), faculty instruction (9, IQR 2), ease of use (9, IQR 2), face validity (8, IQR 3), and overall course (9, IQR 2). On multivariate analysis, there was no difference in rating of domains between postgraduate years. Sixty-seven percent (42/63) believe that simulation training should be a requirement of Urology residency. Ninety-seven percent (63/65) viewed the laboratory as beneficial to their education. This workshop model is a valuable training experience for residents. Most participants believe that surgical simulation is beneficial and should be a requirement for Urology residency. High ratings of usefulness for each exercise demonstrated excellent face validity provided by the course. Copyright © 2017 Elsevier Inc. All rights reserved.

Dynamical Downscaling of NASA/GISS ModelE: Continuous, Multi-Year WRF Simulations

NASA Astrophysics Data System (ADS)

Otte, T.; Bowden, J. H.; Nolte, C. G.; Otte, M. J.; Herwehe, J. A.; Faluvegi, G.; Shindell, D. T.

2010-12-01

The WRF Model is being used at the U.S. EPA for dynamical downscaling of the NASA/GISS ModelE fields to assess regional impacts of climate change in the United States. The WRF model has been successfully linked to the ModelE fields in their raw hybrid vertical coordinate, and continuous, multi-year WRF downscaling simulations have been performed. WRF will be used to downscale decadal time slices of ModelE for recent past, current, and future climate as the simulations being conducted for the IPCC Fifth Assessment Report become available. This presentation will focus on the sensitivity to interior nudging within the RCM. The use of interior nudging for downscaled regional climate simulations has been somewhat controversial over the past several years but has been recently attracting attention. Several recent studies that have used reanalysis (i.e., verifiable) fields as a proxy for GCM input have shown that interior nudging can be beneficial toward achieving the desired downscaled fields. In this study, the value of nudging will be shown using fields from ModelE that are downscaled using WRF. Several different methods of nudging are explored, and it will be shown that the method of nudging and the choices made with respect to how nudging is used in WRF are critical to balance the constraint of ModelE against the freedom of WRF to develop its own fields.

Global climate simulations at 3000-year intervals for the last 21 000 years with the GENMOM coupled atmosphere–ocean model

USGS Publications Warehouse

Alder, Jay R.; Hostetler, Steven W.

2015-01-01

We apply GENMOM, a coupled atmosphere–ocean climate model, to simulate eight equilibrium time slices at 3000-year intervals for the past 21 000 years forced by changes in Earth–Sun geometry, atmospheric greenhouse gases (GHGs), continental ice sheets, and sea level. Simulated global cooling during the Last Glacial Maximum (LGM) is 3.8 ◦C and the rate of post-glacial warming is in overall agreement with recently published temperature reconstructions. The greatest rate of warming occurs between 15 and 12 ka (2.4 ◦C over land, 0.7 ◦C over oceans, and 1.4 ◦C globally) in response to changes in radiative forcing from the diminished extent of the Northern Hemisphere (NH) ice sheets and increases in GHGs and NH summer insolation. The modeled LGM and 6 ka temperature and precipitation climatologies are generally consistent with proxy reconstructions, the PMIP2 and PMIP3 simulations, and other paleoclimate data–model analyses. The model does not capture the mid-Holocene “thermal maximum” and gradual cooling to preindustrial (PI) global temperature found in the data. Simulated monsoonal precipitation in North Africa peaks between 12 and 9 ka at values ∼ 50 % greater than those of the PI, and Indian monsoonal precipitation peaks at 12 and 9 ka at values ∼ 45 % greater than the PI. GENMOM captures the reconstructed LGM extent of NH and Southern Hemisphere (SH) sea ice. The simulated present-day Antarctica Circumpolar Current (ACC) is ∼ 48 % weaker than the observed (62 versus 119 Sv). The simulated present-day Atlantic Meridional Overturning Circulation (AMOC) of 19.3 ± 1.4 Sv on the Bermuda Rise (33◦ N) is comparable with observed value of 18.7 ± 4.8 Sv. AMOC at 33◦ N is reduced by ∼ 15 % during the LGM, and the largest post-glacial increase (∼ 11 %) occurs during the 15 ka time slice.

Influence of land use on rainfall simulation results in the Souss basin, Morocco

NASA Astrophysics Data System (ADS)

Peter, Klaus Daniel; Ries, Johannes B.; Hssaine, Ali Ait

2013-04-01

Situated between the High and Anti-Atlas, the Souss basin is characterized by a dynamic land use change. It is one of the fastest growing agricultural regions of Morocco. Traditional mixed agriculture is replaced by extensive plantations of citrus fruits, bananas and vegetables in monocropping, mainly for the European market. For the implementation of the land use change and further expansion of the plantations into marginal land which was former unsuitable for agriculture, land levelling by heavy machinery is used to plane the fields and close the widespread gullies. These gully systems are cutting deep between the plantations and other arable land. Their development started already over 400 years ago with the introduction of sugar production. Heavy rainfall events lead to further strong soil and gully erosion in this with 200 mm mean annual precipitation normally arid region. Gullies are cutting into the arable land or are re-excavating their old stream courses. On the test sites around the city of Taroudant, a total of 122 rainfall simulations were conducted to analyze the susceptibility of soils to surface runoff and soil erosion under different land use. A small portable nozzle rainfall simulator is used for the rainfall simulation experiments, quantifying runoff and erosion rates on micro-plots with a size of 0.28 m2. A motor pump boosts the water regulated by a flow metre into the commercial full cone nozzle at a height of 2 m. The rainfall intensity is maintained at about 40 mm h-1 for each of the 30 min lasting experiments. Ten categories of land use are classified for different stages of levelling, fallow land, cultivation and rangeland. Results show that mean runoff coefficients and mean sediment loads are significantly higher (1.4 and 3.5 times respectively) on levelled study sites compared to undisturbed sites. However, the runoff coefficients of all land use types are relatively equal and reach high median coefficients from 39 to 56 %. Only the

Rapid genetic divergence in response to 15 years of simulated climate change.

PubMed

Ravenscroft, Catherine H; Whitlock, Raj; Fridley, Jason D

2015-11-01

Genetic diversity may play an important role in allowing individual species to resist climate change, by permitting evolutionary responses. Our understanding of the potential for such responses to climate change remains limited, and very few experimental tests have been carried out within intact ecosystems. Here, we use amplified fragment length polymorphism (AFLP) data to assess genetic divergence and test for signatures of evolutionary change driven by long-term simulated climate change applied to natural grassland at Buxton Climate Change Impacts Laboratory (BCCIL). Experimental climate treatments were applied to grassland plots for 15 years using a replicated and spatially blocked design and included warming, drought and precipitation treatments. We detected significant genetic differentiation between climate change treatments and control plots in two coexisting perennial plant study species (Festuca ovina and Plantago lanceolata). Outlier analyses revealed a consistent signature of selection associated with experimental climate treatments at individual AFLP loci in P. lanceolata, but not in F. ovina. Average background differentiation at putatively neutral AFLP loci was close to zero, and genomewide genetic structure was associated neither with species abundance changes (demography) nor with plant community-level responses to long-term climate treatments. Our results demonstrate genetic divergence in response to a suite of climatic environments in reproductively mature populations of two perennial plant species and are consistent with an evolutionary response to climatic selection in P. lanceolata. These genetic changes have occurred in parallel with impacts on plant community structure and may have contributed to the persistence of individual species through 15 years of simulated climate change at BCCIL. © 2015 The Authors. Global Change Biology Bioenergy Published by John Wiley & Sons Ltd.

Impact of Simulation Training on Time to Initiation of Cardiopulmonary Resuscitation for First-Year Pediatrics Residents

PubMed Central

Ross, Joshua C.; Trainor, Jennifer L.; Eppich, Walter J.; Adler, Mark D.

2013-01-01

Background Pediatrics residents have few opportunities to perform cardiopulmonary resuscitation (CPR). Enhancing the quality of CPR is a key factor to improving outcomes for cardiopulmonary arrest in children and requires effective training strategies. Objective To evaluate the effectiveness of a simulation-based intervention to reduce first-year pediatrics residents' time for 3 critical actions in CPR: (1) call for help, (2) initiate bag-mask ventilation, and (3) initiate chest compressions. Methods A prospective study involving 31 first-year pediatrics residents at a children's hospital assigned to an early or late (control) intervention group. Residents underwent baseline assessment followed by repeat evaluations at 3 and 6 months. Time to critical actions was scored by video review. A 90-minute educational intervention focused on skill practice was conducted following baseline evaluation for the early-intervention group and following 3-month evaluation for the late-intervention group. Primary outcome was change in time to initiating the 3 critical actions. Change in time was analyzed by comparison of Kaplan-Meier curves, using the log-rank test. A 10% sample was timed by a second rater. Agreement was assessed using intraclass correlation (ICC). Results There was a statistically significant reduction in time for all 3 critical actions between baseline and 3-month evaluation in the early intervention group; this was not observed in the late (control) group. Rater agreement was excellent (ICC ≥ 0.99). Conclusions A simulation-based educational intervention significantly reduced time to initiation of CPR for first-year pediatrics residents. Simulation training facilitated acquisition of critical CPR skills that have the potential to impact patient outcome. PMID:24455010

Initial Data Analysis Results for ATD-2 ISAS HITL Simulation

NASA Technical Reports Server (NTRS)

Lee, Hanbong

2017-01-01

To evaluate the operational procedures and information requirements for the core functional capabilities of the ATD-2 project, such as tactical surface metering tool, APREQ-CFR procedure, and data element exchanges between ramp and tower, human-in-the-loop (HITL) simulations were performed in March, 2017. This presentation shows the initial data analysis results from the HITL simulations. With respect to the different runway configurations and metering values in tactical surface scheduler, various airport performance metrics were analyzed and compared. These metrics include gate holding time, taxi-out in time, runway throughput, queue size and wait time in queue, and TMI flight compliance. In addition to the metering value, other factors affecting the airport performance in the HITL simulation, including run duration, runway changes, and TMI constraints, are also discussed.

Exploring the optimal economic timing for crop tree release treatments in hardwoods: results from simulation

Treesearch

Chris B. LeDoux; Gary W. Miller

2008-01-01

In this study we used data from 16 Appalachian hardwood stands, a growth and yield computer simulation model, and stump-to-mill logging cost-estimating software to evaluate the optimal economic timing of crop tree release (CTR) treatments. The simulated CTR treatments consisted of one-time logging operations at stand age 11, 23, 31, or 36 years, with the residual...

Numerical simulation of granular flows : comparison with experimental results

NASA Astrophysics Data System (ADS)

Pirulli, M.; Mangeney-Castelnau, A.; Lajeunesse, E.; Vilotte, J.-P.; Bouchut, F.; Bristeau, M. O.; Perthame, B.

2003-04-01

Granular avalanches such as rock or debris flows regularly cause large amounts of human and material damages. Numerical simulation of granular avalanches should provide a useful tool for investigating, within realistic geological contexts, the dynamics of these flows and of their arrest phase and for improving the risk assessment of such natural hazards. Validation of debris avalanche numerical model on granular experiments over inclined plane is performed here. The comparison is performed by simulating granular flow of glass beads from a reservoir through a gate down an inclined plane. This unsteady situation evolves toward the steady state observed in the laboratory. Furthermore simulation exactly reproduces the arrest phase obtained by suddenly closing the gate of the reservoir once a thick flow has developped. The spreading of a granular mass released from rest at the top of a rough inclined plane is also investigated. The evolution of the avalanche shape, the velocity and the characteristics of the arrest phase are compared with experimental results and analysis of the involved forces are studied for various flow laws.

Influence of photon energy cuts on PET Monte Carlo simulation results.

PubMed

Mitev, Krasimir; Gerganov, Georgi; Kirov, Assen S; Schmidtlein, C Ross; Madzhunkov, Yordan; Kawrakow, Iwan

2012-07-01

The purpose of this work is to study the influence of photon energy cuts on the results of positron emission tomography (PET) Monte Carlo (MC) simulations. MC simulations of PET scans of a box phantom and the NEMA image quality phantom are performed for 32 photon energy cut values in the interval 0.3-350 keV using a well-validated numerical model of a PET scanner. The simulations are performed with two MC codes, egs_pet and GEANT4 Application for Tomographic Emission (GATE). The effect of photon energy cuts on the recorded number of singles, primary, scattered, random, and total coincidences as well as on the simulation time and noise-equivalent count rate is evaluated by comparing the results for higher cuts to those for 1 keV cut. To evaluate the effect of cuts on the quality of reconstructed images, MC generated sinograms of PET scans of the NEMA image quality phantom are reconstructed with iterative statistical reconstruction. The effects of photon cuts on the contrast recovery coefficients and on the comparison of images by means of commonly used similarity measures are studied. For the scanner investigated in this study, which uses bismuth germanate crystals, the transport of Bi X(K) rays must be simulated in order to obtain unbiased estimates for the number of singles, true, scattered, and random coincidences as well as for an unbiased estimate of the noise-equivalent count rate. Photon energy cuts higher than 170 keV lead to absorption of Compton scattered photons and strongly increase the number of recorded coincidences of all types and the noise-equivalent count rate. The effect of photon cuts on the reconstructed images and the similarity measures used for their comparison is statistically significant for very high cuts (e.g., 350 keV). The simulation time decreases slowly with the increase of the photon cut. The simulation of the transport of characteristic x rays plays an important role, if an accurate modeling of a PET scanner system is to be achieved

Results of intravehicular manned cargo-transfer studies in simulated weightlessness

NASA Technical Reports Server (NTRS)

Spady, A. A., Jr.; Beasley, G. P.; Yenni, K. R.; Eisele, D. F.

1972-01-01

A parametric investigation was conducted in a water immersion simulator to determine the effect of package mass, moment of inertia, and size on the ability of man to transfer cargo in simulated weightlessness. Results from this study indicate that packages with masses of at least 744 kg and moments of inertia of at least 386 kg-m2 can be manually handled and transferred satisfactorily under intravehicular conditions using either one- or two-rail motion aids. Data leading to the conclusions and discussions of test procedures and equipment are presented.

Vibronic coupling simulations for linear and nonlinear optical processes: Simulation results

NASA Astrophysics Data System (ADS)

Silverstein, Daniel W.; Jensen, Lasse

2012-02-01

A vibronic coupling model based on time-dependent wavepacket approach is applied to simulate linear optical processes, such as one-photon absorbance and resonance Raman scattering, and nonlinear optical processes, such as two-photon absorbance and resonance hyper-Raman scattering, on a series of small molecules. Simulations employing both the long-range corrected approach in density functional theory and coupled cluster are compared and also examined based on available experimental data. Although many of the small molecules are prone to anharmonicity in their potential energy surfaces, the harmonic approach performs adequately. A detailed discussion of the non-Condon effects is illustrated by the molecules presented in this work. Linear and nonlinear Raman scattering simulations allow for the quantification of interference between the Franck-Condon and Herzberg-Teller terms for different molecules.

Simulated influences of Lake Agassiz on the climate of central North America 11,000 years ago

USGS Publications Warehouse

Hostetler, S.W.; Bartlein, P.J.; Clark, P.U.; Small, E.E.; Solomon, A.M.

2000-01-01

Eleven thousand years ago, large lakes existed in central and eastern North America along the margin of the Laurentide Ice Sheet. The large-scale North American climate at this time has been simulated with atmospheric general circulation models, but these relatively coarse global models do not resolve potentially important features of the mesoscale circulation that arise from interactions among the atmosphere, ice sheet, and proglacial lakes. Here we present simulations of the climate of central and eastern North America 11,000 years ago with a high-resolution, regional climate model nested within a general circulation model. The simulated climate is in general agreement with that inferred from palaeoecological evidence. Our experiments indicate that through mesoscale atmospheric feedbacks, the annual delivery of moisture to the Laurentide Ice Sheet was diminished at times of a large, cold Lake Agassiz relative to periods of lower lake stands. The resulting changes in the mass balance of the ice sheet may have contributed to fluctuations of the ice margin, thus affecting the routing of fresh water to the North Atlantic Ocean. A retreating ice margin during periods of high lake level may have opened an outlet for discharge of Lake Agassiz into the North Atlantic. A subsequent advance of the ice margin due to greater moisture delivery associated with a low lake level could have dammed the outlet, thereby reducing discharge to the North Atlantic. These variations may have been decisive in causing the Younger Dryas cold even.

Effect of simulation on the ability of first year nursing students to learn vital signs.

PubMed

Eyikara, Evrim; Baykara, Zehra Göçmen

2018-01-01

The acquisition of cognitive, affective and psychomotor knowledge and skills are required in nursing, made possible via an interactive teaching method, such as simulation. This study conducted to identify the impact of simulation on first-year nursing students' ability to learn vital signs. A convenience sample of 90 first-year nursing students enrolled at a University, Ankara, in 2014-2015. Ninety students enrolled for lessons on the "Fundamentals of Nursing" were identified using a simple random sampling method. The students were taught vital signs theory via traditional methods. They were grouped into experimental 1, experimental 2 and control group, of 30 students each. Students in the experimental 1 group attended sessions on simulation and those in the experimental 2 group sessions on laboratory work, followed by simulation. The control group were taught via traditional methods and only attended the laboratory work sessions. The students' cognitive knowledge acquisition was evaluated using a knowledge test before and after the lessons. The ability to measure vital signs in adults (healthy ones and patients) was evaluated using a skill control list. A statistically significant difference was not observed between the groups in terms of the average pre-test scores on knowledge (p>0.050). Groups exposed to simulation obtained statistically significantly higher scores than the control group in post-test knowledge (p<0.050). The ability of the groups exposed to simulation to measure vital signs in healthy adults and patients was more successful than that the control group (p<0.050). This was statistically significant. Simulation had a positive effect on the ability of nursing students to measure vital signs. Thus, simulation should be included in the mainstream curriculum in order to effectively impart nursing knowledge and skills. Copyright © 2017 Elsevier Ltd. All rights reserved.

Have We Really Been Analyzing Terminating Simulations Incorrectly All These Years?

DTIC Science & Technology

2013-12-01

TERMINATING SIMULATIONS INCORRECTLY ALL THESE YEARS? Paul J. Sánchez Operations Research Naval Postgraduate School 1411 Cunningham Road Monterey, CA...measure. If that observation directly represents an end state such as the number of failed components after a week’s operation , or the number of patients...processed in 24 hours of emergency room operations , there’s no problem—the set of values obtained by replication represent a random sample from the

Easing student transition to graduate nurse: a SIMulated Professional Learning Environment (SIMPLE) for final year student nurses.

PubMed

Liaw, Sok Ying; Koh, Yiwen; Dawood, Rabiah; Kowitlawakul, Yanika; Zhou, Wentao; Lau, Siew Tiang

2014-03-01

Preparing nursing students for making the transition to graduate nurse is crucial for entry into practice. Final year student nurses at the National University of Singapore (NUS) are required to undergo a consolidated clinical practice to prepare them for their transition to graduate nurse. To describe the development, implementation and evaluation of a simulation program known as SIMulated Professional Learning Environment (SIMPLE) in preparing the final year student nurses for their clinical practicum in transition to graduate nurse practice. A set of simulation features and best practices were used as conceptual framework to develop and implement the simulation program. 94 final year student nurses participated in the 15-hour SIMPLE program that incorporated multiple simulation scenarios based on actual ward clinical practices. Pre and post-tests were conducted to assess the students' preparedness for their clinical practice in transition to graduate nurse practice. The students also completed a satisfaction questionnaire and open questions to evaluate their simulation experiences. The student nurses demonstrated a significant improvement (t=12.06, p<0.01) on post-test score (mean=117.21, SD=15.17) from pre-test score (mean=97.86, SD=15.08) for their perceived preparedness towards their clinical practicum in transition to graduate nurse practice. They were highly satisfied with their simulation learning. Themes emerged from the comments on the most valuable aspects of the SIMPLE program and ways to improve the program. The study provided evidences on the effectiveness of the SIMPLE program in enhancing the students' preparedness for their transition to graduate nurse practice. A key success of the SIMPLE program was the used of simulation strategy and the involvement of practicing nurses that closely linked the students with the realities of current nursing practice to prepare them for the role of staff nurses. Copyright © 2013 Elsevier Ltd. All rights reserved.

Year-round simulated methane emissions from a permafrost ecosystem in Northeast Siberia

NASA Astrophysics Data System (ADS)

Castro-Morales, Karel; Kleinen, Thomas; Kaiser, Sonja; Zaehle, Sönke; Kittler, Fanny; Kwon, Min Jung; Beer, Christian; Göckede, Mathias

2018-05-01

Wetlands of northern high latitudes are ecosystems highly vulnerable to climate change. Some degradation effects include soil hydrologic changes due to permafrost thaw, formation of deeper active layers, and rising topsoil temperatures that accelerate the degradation of permafrost carbon and increase in CO2 and CH4 emissions. In this work we present 2 years of modeled year-round CH4 emissions into the atmosphere from a Northeast Siberian region in the Russian Far East. We use a revisited version of the process-based JSBACH-methane model that includes four CH4 transport pathways: plant-mediated transport, ebullition and molecular diffusion in the presence or absence of snow. The gas is emitted through wetlands represented by grid cell inundated areas simulated with a TOPMODEL approach. The magnitude of the summertime modeled CH4 emissions is comparable to ground-based CH4 fluxes measured with the eddy covariance technique and flux chambers in the same area of study, whereas wintertime modeled values are underestimated by 1 order of magnitude. In an annual balance, the most important mechanism for transport of methane into the atmosphere is through plants (61 %). This is followed by ebullition ( ˜ 35 %), while summertime molecular diffusion is negligible (0.02 %) compared to the diffusion through the snow during winter ( ˜ 4 %). We investigate the relationship between temporal changes in the CH4 fluxes, soil temperature, and soil moisture content. Our results highlight the heterogeneity in CH4 emissions at landscape scale and suggest that further improvements to the representation of large-scale hydrological conditions in the model will facilitate a more process-oriented land surface scheme and better simulate CH4 emissions under climate change. This is especially necessary at regional scales in Arctic ecosystems influenced by permafrost thaw.

Simulation loop between cad systems, GEANT-4 and GeoModel: Implementation and results

NASA Astrophysics Data System (ADS)

Sharmazanashvili, A.; Tsutskiridze, Niko

2016-09-01

Compare analysis of simulation and as-built geometry descriptions of detector is important field of study for data_vs_Monte-Carlo discrepancies. Shapes consistency and detalization is not important while adequateness of volumes and weights of detector components are essential for tracking. There are 2 main reasons of faults of geometry descriptions in simulation: (1) Difference between simulated and as-built geometry descriptions; (2) Internal inaccuracies of geometry transformations added by simulation software infrastructure itself. Georgian Engineering team developed hub on the base of CATIA platform and several tools enabling to read in CATIA different descriptions used by simulation packages, like XML->CATIA; VP1->CATIA; Geo-Model->CATIA; Geant4->CATIA. As a result it becomes possible to compare different descriptions with each other using the full power of CATIA and investigate both classes of reasons of faults of geometry descriptions. Paper represents results of case studies of ATLAS Coils and End-Cap toroid structures.

A Novel Simulation Technician Laboratory Design: Results of a Survey-Based Study

PubMed Central

Hughes, Patrick G; Friedl, Ed; Ortiz Figueroa, Fabiana; Cepeda Brito, Jose R; Frey, Jennifer; Birmingham, Lauren E; Atkinson, Steven Scott

2016-01-01

Objective  The purpose of this study was to elicit feedback from simulation technicians prior to developing the first simulation technician-specific simulation laboratory in Akron, OH. Background Simulation technicians serve a vital role in simulation centers within hospitals/health centers around the world. The first simulation technician degree program in the US has been approved in Akron, OH. To satisfy the requirements of this program and to meet the needs of this special audience of learners, a customized simulation lab is essential.  Method A web-based survey was circulated to simulation technicians prior to completion of the lab for the new program. The survey consisted of questions aimed at identifying structural and functional design elements of a novel simulation center for the training of simulation technicians. Quantitative methods were utilized to analyze data. Results Over 90% of technicians (n=65) think that a lab designed explicitly for the training of technicians is novel and beneficial. Approximately 75% of respondents think that the space provided appropriate audiovisual (AV) infrastructure and space to evaluate the ability of technicians to be independent. The respondents think that the lab needed more storage space, visualization space for a large number of students, and more space in the technical/repair area. Conclusions  A space designed for the training of simulation technicians was considered to be beneficial. This laboratory requires distinct space for technical repair, adequate bench space for the maintenance and repair of simulators, an appropriate AV infrastructure, and space to evaluate the ability of technicians to be independent. PMID:27096134

Assessment of effectiveness of geologic isolation systems. Geologic-simulation model for a hypothetical site in the Columbia Plateau. Volume 2: results

DOE Office of Scientific and Technical Information (OSTI.GOV)

Foley, M.G.; Petrie, G.M.; Baldwin, A.J.

1982-06-01

This report contains the input data and computer results for the Geologic Simulation Model. This model is described in detail in the following report: Petrie, G.M., et. al. 1981. Geologic Simulation Model for a Hypothetical Site in the Columbia Plateau, Pacific Northwest Laboratory, Richland, Washington. The Geologic Simulation Model is a quasi-deterministic process-response model which simulates, for a million years into the future, the development of the geologic and hydrologic systems of the ground-water basin containing the Pasco Basin. Effects of natural processes on the ground-water hydrologic system are modeled principally by rate equations. The combined effects and synergistic interactionsmore » of different processes are approximated by linear superposition of their effects during discrete time intervals in a stepwise-integration approach.« less

Aedes albopictus in Rome: results and perspectives after 10 years of monitoring.

PubMed

Severini, F; Di Luca, M; Toma, L; Romi, R

2008-06-01

In 1997, Aedes albopictus (Skuse 1894) was detected in Rome in two opposite areas of the city. In the following 2 years, the species quickly spread. In 2000, scattered foci of the species were reported in the whole urban area and in the outskirts of the capital city. In Rome, Ae. albopictus seems to have found optimal environmental conditions to proliferate and to overwinter through and without diapausing eggs. In ten years Ae. albopictus has colonized the whole urban area through three phases: first massive spread, following maintenance of infestation, and colonization of alternative winter breeding sites with favorable climatic conditions. Data collected during the 2007 show that rainfall is no longer the most important factor for the development of the species, with respect to the past. In fact Ae. albopictus probably has found new alternative larval breeding sites through the colonization of small water collections refilled periodically by human activities. During 2007-2008 winter season, in order to evaluate the species adaptability, a study of eggs hatching and length of larval cycle at low temperatures, was carried out in laboratory and in simulated field conditions. Data and results are showed and discussed also by the light of existing literature.

Boundary pint corrections for variable radius plots - simulation results

Treesearch

Margaret Penner; Sam Otukol

2000-01-01

The boundary plot problem is encountered when a forest inventory plot includes two or more forest conditions. Depending on the correction method used, the resulting estimates can be biased. The various correction alternatives are reviewed. No correction, area correction, half sweep, and toss-back methods are evaluated using simulation on an actual data set. Based on...

Improving the trust in results of numerical simulations and scientific data analytics

DOE Office of Scientific and Technical Information (OSTI.GOV)

Cappello, Franck; Constantinescu, Emil; Hovland, Paul

This white paper investigates several key aspects of the trust that a user can give to the results of numerical simulations and scientific data analytics. In this document, the notion of trust is related to the integrity of numerical simulations and data analytics applications. This white paper complements the DOE ASCR report on Cybersecurity for Scientific Computing Integrity by (1) exploring the sources of trust loss; (2) reviewing the definitions of trust in several areas; (3) providing numerous cases of result alteration, some of them leading to catastrophic failures; (4) examining the current notion of trust in numerical simulation andmore » scientific data analytics; (5) providing a gap analysis; and (6) suggesting two important research directions and their respective research topics. To simplify the presentation without loss of generality, we consider that trust in results can be lost (or the results’ integrity impaired) because of any form of corruption happening during the execution of the numerical simulation or the data analytics application. In general, the sources of such corruption are threefold: errors, bugs, and attacks. Current applications are already using techniques to deal with different types of corruption. However, not all potential corruptions are covered by these techniques. We firmly believe that the current level of trust that a user has in the results is at least partially founded on ignorance of this issue or the hope that no undetected corruptions will occur during the execution. This white paper explores the notion of trust and suggests recommendations for developing a more scientifically grounded notion of trust in numerical simulation and scientific data analytics. We first formulate the problem and show that it goes beyond previous questions regarding the quality of results such as V&V, uncertainly quantification, and data assimilation. We then explore the complexity of this difficult problem, and we sketch complementary

True fir spacing trials: 10-year results.

Treesearch

Robert O. Curtis

2008-01-01

Eighteen precommercial thinning trials were established in true fir-hemlock stands in the Olympic Mountains and the west side of the Cascade Range during the period 1987 through 1994. This paper updates a previous report, with results for the first 10 years after establishment. Results are given for (1) all trees, (2) the largest 80 per acre of any species, and (3)...

Comparison of the analytical and simulation results of the equilibrium beam profile

DOE Office of Scientific and Technical Information (OSTI.GOV)

Liu, Z. J.; Zhu Shaoping; Cao, L. H.

2007-10-15

The evolution of high current electron beams in dense plasmas has been investigated by using two-dimensional particle-in-cell (PIC) simulations with immobile ions. It is shown that electron beams are split into many filaments at the beginning due to the Weibel instability, and then different filamentation beams attract each other and coalesce. The profile of the filaments can be described by formulas. Hammer et al. [Phys. Fluids 13, 1831 (1970)] developed a self-consistent relativistic electron beam model that allows the propagation of relativistic electron fluxes in excess of the Alfven-Lawson critical-current limit for a fully neutralized beam. The equilibrium solution hasmore » been observed in the simulation results, but the electron distribution function assumed by Hammer et al. is different from the simulation results.« less

Changing Characteristics of convective storms: Results from a continental-scale convection-permitting climate simulations

NASA Astrophysics Data System (ADS)

Prein, A. F.; Ikeda, K.; Liu, C.; Bullock, R.; Rasmussen, R.

2016-12-01

Convective storms are causing extremes such as flooding, landslides, and wind gusts and are related to the development of tornadoes and hail. Convective storms are also the dominant source of summer precipitation in most regions of the Contiguous United States. So far little is known about how convective storms might change due to global warming. This is mainly because of the coarse grid spacing of state-of-the-art climate models that are not able to resolve deep convection explicitly. Instead, coarse resolution models rely on convective parameterization schemes that are a major source of errors and uncertainties in climate change projections. Convection-permitting climate simulations, with grid-spacings smaller than 4 km, show significant improvements in the simulation of convective storms by representing deep convection explicitly. Here we use a pair of 13-year long current and future convection-permitting climate simulations that cover large parts of North America. We use the Method for Object-Based Diagnostic Evaluation (MODE) that incorporates the time dimension (MODE-TD) to analyze the model performance in reproducing storm features in the current climate and to investigate their potential future changes. We show that the model is able to accurately reproduce the main characteristics of convective storms in the present climate. The comparison with the future climate simulation shows that convective storms significantly increase in frequency, intensity, and size. Furthermore, they are projected to move slower which could result in a substantial increase in convective storm-related hazards such as flash floods, debris flows, and landslides. Some regions, such as the North Atlantic, might experience a regime shift that leads to significantly stronger storms that are unrepresented in the current climate.

Planck 2015 results. XII. Full focal plane simulations

NASA Astrophysics Data System (ADS)

Planck Collaboration; Ade, P. A. R.; Aghanim, N.; Arnaud, M.; Ashdown, M.; Aumont, J.; Baccigalupi, C.; Banday, A. J.; Barreiro, R. B.; Bartlett, J. G.; Bartolo, N.; Battaner, E.; Benabed, K.; Benoît, A.; Benoit-Lévy, A.; Bernard, J.-P.; Bersanelli, M.; Bielewicz, P.; Bock, J. J.; Bonaldi, A.; Bonavera, L.; Bond, J. R.; Borrill, J.; Bouchet, F. R.; Boulanger, F.; Bucher, M.; Burigana, C.; Butler, R. C.; Calabrese, E.; Cardoso, J.-F.; Castex, G.; Catalano, A.; Challinor, A.; Chamballu, A.; Chiang, H. C.; Christensen, P. R.; Clements, D. L.; Colombi, S.; Colombo, L. P. L.; Combet, C.; Couchot, F.; Coulais, A.; Crill, B. P.; Curto, A.; Cuttaia, F.; Danese, L.; Davies, R. D.; Davis, R. J.; de Bernardis, P.; de Rosa, A.; de Zotti, G.; Delabrouille, J.; Delouis, J.-M.; Désert, F.-X.; Dickinson, C.; Diego, J. M.; Dolag, K.; Dole, H.; Donzelli, S.; Doré, O.; Douspis, M.; Ducout, A.; Dupac, X.; Efstathiou, G.; Elsner, F.; Enßlin, T. A.; Eriksen, H. K.; Fergusson, J.; Finelli, F.; Forni, O.; Frailis, M.; Fraisse, A. A.; Franceschi, E.; Frejsel, A.; Galeotta, S.; Galli, S.; Ganga, K.; Ghosh, T.; Giard, M.; Giraud-Héraud, Y.; Gjerløw, E.; González-Nuevo, J.; Górski, K. M.; Gratton, S.; Gregorio, A.; Gruppuso, A.; Gudmundsson, J. E.; Hansen, F. K.; Hanson, D.; Harrison, D. L.; Henrot-Versillé, S.; Hernández-Monteagudo, C.; Herranz, D.; Hildebrandt, S. R.; Hivon, E.; Hobson, M.; Holmes, W. A.; Hornstrup, A.; Hovest, W.; Huffenberger, K. M.; Hurier, G.; Jaffe, A. H.; Jaffe, T. R.; Jones, W. C.; Juvela, M.; Karakci, A.; Keihänen, E.; Keskitalo, R.; Kiiveri, K.; Kisner, T. S.; Kneissl, R.; Knoche, J.; Kunz, M.; Kurki-Suonio, H.; Lagache, G.; Lamarre, J.-M.; Lasenby, A.; Lattanzi, M.; Lawrence, C. R.; Leonardi, R.; Lesgourgues, J.; Levrier, F.; Liguori, M.; Lilje, P. B.; Linden-Vørnle, M.; Lindholm, V.; López-Caniego, M.; Lubin, P. M.; Macías-Pérez, J. F.; Maggio, G.; Maino, D.; Mandolesi, N.; Mangilli, A.; Maris, M.; Martin, P. G.; Martínez-González, E.; Masi, S.; Matarrese, S.; McGehee, P.; Meinhold, P. R.; Melchiorri, A.; Melin, J.-B.; Mendes, L.; Mennella, A.; Migliaccio, M.; Mitra, S.; Miville-Deschênes, M.-A.; Moneti, A.; Montier, L.; Morgante, G.; Mortlock, D.; Moss, A.; Munshi, D.; Murphy, J. A.; Naselsky, P.; Nati, F.; Natoli, P.; Netterfield, C. B.; Nørgaard-Nielsen, H. U.; Noviello, F.; Novikov, D.; Novikov, I.; Oxborrow, C. A.; Paci, F.; Pagano, L.; Pajot, F.; Paoletti, D.; Pasian, F.; Patanchon, G.; Pearson, T. J.; Perdereau, O.; Perotto, L.; Perrotta, F.; Pettorino, V.; Piacentini, F.; Piat, M.; Pierpaoli, E.; Pietrobon, D.; Plaszczynski, S.; Pointecouteau, E.; Polenta, G.; Pratt, G. W.; Prézeau, G.; Prunet, S.; Puget, J.-L.; Rachen, J. P.; Rebolo, R.; Reinecke, M.; Remazeilles, M.; Renault, C.; Renzi, A.; Ristorcelli, I.; Rocha, G.; Roman, M.; Rosset, C.; Rossetti, M.; Roudier, G.; Rubiño-Martín, J. A.; Rusholme, B.; Sandri, M.; Santos, D.; Savelainen, M.; Scott, D.; Seiffert, M. D.; Shellard, E. P. S.; Spencer, L. D.; Stolyarov, V.; Stompor, R.; Sudiwala, R.; Sutton, D.; Suur-Uski, A.-S.; Sygnet, J.-F.; Tauber, J. A.; Terenzi, L.; Toffolatti, L.; Tomasi, M.; Tristram, M.; Tucci, M.; Tuovinen, J.; Valenziano, L.; Valiviita, J.; Van Tent, B.; Vielva, P.; Villa, F.; Wade, L. A.; Wandelt, B. D.; Wehus, I. K.; Welikala, N.; Yvon, D.; Zacchei, A.; Zonca, A.

2016-09-01

We present the 8th full focal plane simulation set (FFP8), deployed in support of the Planck 2015 results. FFP8 consists of 10 fiducial mission realizations reduced to 18 144 maps, together with the most massive suite of Monte Carlo realizations of instrument noise and CMB ever generated, comprising 104 mission realizations reduced to about 106 maps. The resulting maps incorporate the dominant instrumental, scanning, and data analysis effects, and the remaining subdominant effects will be included in future updates. Generated at a cost of some 25 million CPU-hours spread across multiple high-performance-computing (HPC) platforms, FFP8 is used to validate and verify analysis algorithms and their implementations, and to remove biases from and quantify uncertainties in the results of analyses of the real data.

Ca-Pri a Cellular Automata Phenomenological Research Investigation: Simulation Results

NASA Astrophysics Data System (ADS)

Iannone, G.; Troisi, A.

2013-05-01

Following the introduction of a phenomenological cellular automata (CA) model capable to reproduce city growth and urban sprawl, we develop a toy model simulation considering a realistic framework. The main characteristic of our approach is an evolution algorithm based on inhabitants preferences. The control of grown cells is obtained by means of suitable functions which depend on the initial condition of the simulation. New born urban settlements are achieved by means of a logistic evolution of the urban pattern while urban sprawl is controlled by means of the population evolution function. In order to compare model results with a realistic urban framework we have considered, as the area of study, the island of Capri (Italy) in the Mediterranean Sea. Two different phases of the urban evolution on the island have been taken into account: a new born initial growth as induced by geographic suitability and the simulation of urban spread after 1943 induced by the population evolution after this date.

How sleep problems contribute to simulator sickness: Preliminary results from a realistic driving scenario.

PubMed

Altena, Ellemarije; Daviaux, Yannick; Sanz-Arigita, Ernesto; Bonhomme, Emilien; de Sevin, Étienne; Micoulaud-Franchi, Jean-Arthur; Bioulac, Stéphanie; Philip, Pierre

2018-04-17

Virtual reality and simulation tools enable us to assess daytime functioning in environments that simulate real life as close as possible. Simulator sickness, however, poses a problem in the application of these tools, and has been related to pre-existing health problems. How sleep problems contribute to simulator sickness has not yet been investigated. In the current study, 20 female chronic insomnia patients and 32 female age-matched controls drove in a driving simulator covering realistic city, country and highway scenes. Fifty percent of the insomnia patients as opposed to 12.5% of controls reported excessive simulator sickness leading to experiment withdrawal. In the remaining participants, patients with insomnia showed overall increased levels of oculomotor symptoms even before driving, while nausea symptoms further increased after driving. These results, as well as the realistic simulation paradigm developed, give more insight on how vestibular and oculomotor functions as well as interoceptive functions are affected in insomnia. Importantly, our results have direct implications for both the actual driving experience and the wider context of deploying simulation techniques to mimic real life functioning, in particular in those professions often exposed to sleep problems. © 2018 European Sleep Research Society.

Toward robust estimation of the components of forest population change: simulation results

Treesearch

Francis A. Roesch

2014-01-01

This report presents the full simulation results of the work described in Roesch (2014), in which multiple levels of simulation were used to test the robustness of estimators for the components of forest change. In that study, a variety of spatial-temporal populations were created based on, but more variable than, an actual forest monitoring dataset, and then those...

The Aurora radiation-hydrodynamical simulations of reionization: calibration and first results

NASA Astrophysics Data System (ADS)

Pawlik, Andreas H.; Rahmati, Alireza; Schaye, Joop; Jeon, Myoungwon; Dalla Vecchia, Claudio

2017-04-01

We introduce a new suite of radiation-hydrodynamical simulations of galaxy formation and reionization called Aurora. The Aurora simulations make use of a spatially adaptive radiative transfer technique that lets us accurately capture the small-scale structure in the gas at the resolution of the hydrodynamics, in cosmological volumes. In addition to ionizing radiation, Aurora includes galactic winds driven by star formation and the enrichment of the universe with metals synthesized in the stars. Our reference simulation uses 2 × 5123 dark matter and gas particles in a box of size 25 h-1 comoving Mpc with a force softening scale of at most 0.28 h-1 kpc. It is accompanied by simulations in larger and smaller boxes and at higher and lower resolution, employing up to 2 × 10243 particles, to investigate numerical convergence. All simulations are calibrated to yield simulated star formation rate functions in close agreement with observational constraints at redshift z = 7 and to achieve reionization at z ≈ 8.3, which is consistent with the observed optical depth to reionization. We focus on the design and calibration of the simulations and present some first results. The median stellar metallicities of low-mass galaxies at z = 6 are consistent with the metallicities of dwarf galaxies in the Local Group, which are believed to have formed most of their stars at high redshifts. After reionization, the mean photoionization rate decreases systematically with increasing resolution. This coincides with a systematic increase in the abundance of neutral hydrogen absorbers in the intergalactic medium.

Does teaching of documentation of shoulder dystocia delivery through simulation result in improved documentation in real life?

PubMed

Comeau, Robyn; Craig, Catherine

2014-03-01

Documentation of deliveries complicated by shoulder dystocia is a valuable communication skill necessary for residents to attain during residency training. Our objective was to determine whether the teaching of documentation of shoulder dystocia in a simulation environment would translate to improved documentation of the event in an actual clinical situation. We conducted a cohort study involving obstetrics and gynaecology residents in years 2 to 5 between November 2010 and December 2012. Each resident participated in a shoulder dystocia simulation teaching session and was asked to write a delivery note immediately afterwards. They were given feedback regarding their performance of the delivery and their documentation of the events. Following this, dictated records of shoulder dystocia deliveries immediately before and after the simulation session were identified through the Meditech system. An itemized checklist was used to assess the quality of residents' dictated documentation before and after the simulation session. All eligible residents (18) enrolled in the study, and 17 met the inclusion criteria. For 10 residents (59%) documentation of a delivery with shoulder dystocia was present before and after the simulation session, for five residents (29%) it was only present before the session, and for two residents (18%) it was only present after the session. When residents were assessed as a group, there were no differences in the proportion of residents recording items on the checklist before and after the simulation session (P > 0.05 for all). Similarly, analysis of the performance of the10 residents who had dictated documentation both before and after the session showed no differences in the number of elements recorded on dictations done before and after the simulation session (P > 0.05 for all). The teaching of shoulder dystocia documentation through simulation did not result in a measurable improvement in the quality of documentation of shoulder dystocia in

Long-range speckle imaging theory, simulation, and brassboard results

NASA Astrophysics Data System (ADS)

Riker, Jim F.; Tyler, Glenn A.; Vaughn, Jeff L.

2017-09-01

In the SPIE 2016 Unconventional Imaging session, the authors laid out a breakthrough new theory for active array imaging that exploits the speckle return to generate a high-resolution picture of the target. Since then, we have pursued that theory even in long-range (<1000-km) engagement scenarios and shown how we can obtain that high-resolution image of the target using only a few illuminators, or by using many illuminators. There is a trade of illuminators versus receivers, but many combinations provide the same synthetic aperture resolution. We will discuss that trade, along with the corresponding radiometric and speckle-imaging Signal-to-Noise Ratios (SNR) for geometries that can fit on relatively small aircraft, such as an Unmanned Aerial Vehicle (UAV). Furthermore, we have simulated the performance of the technique, and we have created a laboratory version of the approach that is able to obtain high-resolution speckle imagery. The principal results presented in this paper are the Signal to Noise Ratios (SNR) for both the radiometric and the speckle imaging portions of the problem, and the simulated results obtained for representative arrays.

DES Y1 Results: Validating Cosmological Parameter Estimation Using Simulated Dark Energy Surveys

DOE Office of Scientific and Technical Information (OSTI.GOV)

MacCrann, N.; et al.

We use mock galaxy survey simulations designed to resemble the Dark Energy Survey Year 1 (DES Y1) data to validate and inform cosmological parameter estimation. When similar analysis tools are applied to both simulations and real survey data, they provide powerful validation tests of the DES Y1 cosmological analyses presented in companion papers. We use two suites of galaxy simulations produced using different methods, which therefore provide independent tests of our cosmological parameter inference. The cosmological analysis we aim to validate is presented in DES Collaboration et al. (2017) and uses angular two-point correlation functions of galaxy number counts and weak lensing shear, as well as their cross-correlation, in multiple redshift bins. While our constraints depend on the specific set of simulated realisations available, for both suites of simulations we find that the input cosmology is consistent with the combined constraints from multiple simulated DES Y1 realizations in themore » $$\\Omega_m-\\sigma_8$$ plane. For one of the suites, we are able to show with high confidence that any biases in the inferred $$S_8=\\sigma_8(\\Omega_m/0.3)^{0.5}$$ and $$\\Omega_m$$ are smaller than the DES Y1 $$1-\\sigma$$ uncertainties. For the other suite, for which we have fewer realizations, we are unable to be this conclusive; we infer a roughly 70% probability that systematic biases in the recovered $$\\Omega_m$$ and $$S_8$$ are sub-dominant to the DES Y1 uncertainty. As cosmological analyses of this kind become increasingly more precise, validation of parameter inference using survey simulations will be essential to demonstrate robustness.« less

A serious game skills competition increases voluntary usage and proficiency of a virtual reality laparoscopic simulator during first-year surgical residents' simulation curriculum.

PubMed

El-Beheiry, Mostafa; McCreery, Greig; Schlachta, Christopher M

2017-04-01

The objective of this study was to assess the effect of a serious game skills competition on voluntary usage of a laparoscopic simulator among first-year surgical residents' standard simulation curriculum. With research ethics board approval, informed consent was obtained from first-year surgical residents enrolled in an introductory surgical simulation curriculum. The class of 2013 served as a control cohort following the standard curriculum which mandates completion of six laparoscopic simulator skill tasks. For the 2014 competition cohort, the only change introduced was the biweekly and monthly posting of a leader board of the top three and ten fastest peg transfer times. Entry surveys were administered assessing attitudes towards simulation-based training and competition. Cohorts were observed for 5 months. There were 24 and 25 residents in the control and competition cohorts, respectively. The competition cohort overwhelmingly (76 %) stated that they were not motivated to deliberate practice by competition. Median total simulator usage time was 132 min (IQR = 214) in the competition cohort compared to 89 (IQR = 170) in the control cohort. The competition cohort completed their course requirements significantly earlier than the control cohort (χ 2  = 6.5, p = 0.01). There was a significantly greater proportion of residents continuing to use the simulator voluntarily after completing their course requirements in the competition cohort (44 vs. 4 %; p = 0.002). Residents in the competition cohort were significantly faster at peg transfer (194 ± 66 vs. 233 ± 53 s, 95 % CI of difference = 4-74 s; p = 0.03) and significantly decreased their completion time by 33 ± 54 s (95 % CI 10-56 s; paired t test, p = 0.007). A simple serious games skills competition increased voluntary usage and performance on a laparoscopic simulator, despite a majority of participants reporting they were not motivated by competition. Future directions should

Planck 2015 results: XII. Full focal plane simulations

DOE PAGES

Ade, P. A. R.; Aghanim, N.; Arnaud, M.; ...

2016-09-20

In this paper, we present the 8th full focal plane simulation set (FFP8), deployed in support of the Planck 2015 results. FFP8 consists of 10 fiducial mission realizations reduced to 18 144 maps, together with the most massive suite of Monte Carlo realizations of instrument noise and CMB ever generated, comprising 10 4 mission realizations reduced to about 10 6 maps. The resulting maps incorporate the dominant instrumental, scanning, and data analysis effects, and the remaining subdominant effects will be included in future updates. Finally, generated at a cost of some 25 million CPU-hours spread across multiple high-performance-computing (HPC) platforms,more » FFP8 is used to validate and verify analysis algorithms and their implementations, and to remove biases from and quantify uncertainties in the results of analyses of the real data.« less

High Fidelity Thermal Simulators for Non-Nuclear Testing: Analysis and Initial Results

NASA Technical Reports Server (NTRS)

Bragg-Sitton, Shannon M.; Dickens, Ricky; Dixon, David

2007-01-01

Non-nuclear testing can be a valuable tool in the development of a space nuclear power system, providing system characterization data and allowing one to work through various fabrication, assembly and integration issues without the cost and time associated with a full ground nuclear test. In a non-nuclear test bed, electric heaters are used to simulate the heat from nuclear fuel. Testing with non-optimized heater elements allows one to assess thermal, heat transfer, and stress related attributes of a given system, but fails to demonstrate the dynamic response that would be present in an integrated, fueled reactor system. High fidelity thermal simulators that match both the static and the dynamic fuel pin performance that would be observed in an operating, fueled nuclear reactor can vastly increase the value of non-nuclear test results. With optimized simulators, the integration of thermal hydraulic hardware tests with simulated neutronie response provides a bridge between electrically heated testing and fueled nuclear testing, providing a better assessment of system integration issues, characterization of integrated system response times and response characteristics, and assessment of potential design improvements' at a relatively small fiscal investment. Initial conceptual thermal simulator designs are determined by simple one-dimensional analysis at a single axial location and at steady state conditions; feasible concepts are then input into a detailed three-dimensional model for comparison to expected fuel pin performance. Static and dynamic fuel pin performance for a proposed reactor design is determined using SINDA/FLUINT thermal analysis software, and comparison is made between the expected nuclear performance and the performance of conceptual thermal simulator designs. Through a series of iterative analyses, a conceptual high fidelity design can developed. Test results presented in this paper correspond to a "first cut" simulator design for a potential

RFI in hybrid loops - Simulation and experimental results.

NASA Technical Reports Server (NTRS)

Ziemer, R. E.; Nelson, D. R.; Raghavan, H. R.

1972-01-01

A digital simulation of an imperfect second-order hybrid phase-locked loop (HPLL) operating in radio frequency interference (RFI) is described. Its performance is characterized in terms of phase error variance and phase error probability density function (PDF). Monte-Carlo simulation is used to show that the HPLL can be superior to the conventional phase-locked loops in RFI backgrounds when minimum phase error variance is the goodness criterion. Similar experimentally obtained data are given in support of the simulation data.

Near-field diffraction from amplitude diffraction gratings: theory, simulation and results

NASA Astrophysics Data System (ADS)

Abedin, Kazi Monowar; Rahman, S. M. Mujibur

2017-08-01

We describe a computer simulation method by which the complete near-field diffract pattern of an amplitude diffraction grating can be generated. The technique uses the method of iterative Fresnel integrals to calculate and generate the diffraction images. Theoretical background as well as the techniques to perform the simulation is described. The program is written in MATLAB, and can be implemented in any ordinary PC. Examples of simulated diffraction images are presented and discussed. The generated images in the far-field where they reduce to Fraunhofer diffraction pattern are also presented for a realistic grating, and compared with the results predicted by the grating equation, which is applicable in the far-field. The method can be used as a tool to teach the complex phenomenon of diffraction in classrooms.

Simulation studies for the evaluation of health information technologies: experiences and results.

PubMed

Ammenwerth, Elske; Hackl, Werner O; Binzer, Kristine; Christoffersen, Tue E H; Jensen, Sanne; Lawton, Kitta; Skjoet, Peter; Nohr, Christian

It is essential for new health information technologies (IT) to undergo rigorous evaluations to ensure they are effective and safe for use in real-world situations. However, evaluation of new health IT is challenging, as field studies are often not feasible when the technology being evaluated is not sufficiently mature. Laboratory-based evaluations have also been shown to have insufficient external validity. Simulation studies seem to be a way to bridge this gap. The aim of this study was to evaluate, using a simulation methodology, the impact of a new prototype of an electronic medication management system on the appropriateness of prescriptions and drug-related activities, including laboratory test ordering or medication changes. This article presents the results of a controlled simulation study with 50 simulation runs, including ten doctors and five simulation patients, and discusses experiences and lessons learnt while conducting the study. Although the new electronic medication management system showed tendencies to improve medication safety when compared with the standard system, this tendency was not significant. Altogether, five distinct situations were identified where the new medication management system did help to improve medication safety. This simulation study provided a good compromise between internal validity and external validity. However, several challenges need to be addressed when undertaking simulation evaluations including: preparation of adequate test cases; training of participants before using unfamiliar applications; consideration of time, effort and costs of conducting the simulation; technical maturity of the evaluated system; and allowing adequate preparation of simulation scenarios and simulation setting. Simulation studies are an interesting but time-consuming approach, which can be used to evaluate newly developed health IT systems, particularly those systems that are not yet sufficiently mature to undergo field evaluation studies.

The experiences of last-year student midwives with High-Fidelity Perinatal Simulation training: A qualitative descriptive study.

PubMed

Vermeulen, Joeri; Beeckman, Katrien; Turcksin, Rivka; Van Winkel, Lies; Gucciardo, Léonardo; Laubach, Monika; Peersman, Wim; Swinnen, Eva

2017-06-01

Simulation training is a powerful and evidence-based teaching method in healthcare. It allows students to develop essential competences that are often difficult to achieve during internships. High-Fidelity Perinatal Simulation exposes them to real-life scenarios in a safe environment. Although student midwives' experiences need to be considered to make the simulation training work, these have been overlooked so far. To explore the experiences of last-year student midwives with High-Fidelity Perinatal Simulation training. A qualitative descriptive study, using three focus group conversations with last-year student midwives (n=24). Audio tapes were transcribed and a thematic content analysis was performed. The entire data set was coded according to recurrent or common themes. To achieve investigator triangulation and confirm themes, discussions among the researchers was incorporated in the analysis. Students found High-Fidelity Perinatal Simulation training to be a positive learning method that increased both their competence and confidence. Their experiences varied over the different phases of the High-Fidelity Perinatal Simulation training. Although uncertainty, tension, confusion and disappointment were experienced throughout the simulation trajectory, they reported that this did not affect their learning and confidence-building. As High-Fidelity Perinatal Simulation training constitutes a helpful learning experience in midwifery education, it could have a positive influence on maternal and neonatal outcomes. In the long term, it could therefore enhance the midwifery profession in several ways. The present study is an important first step in opening up the debate about the pedagogical use of High-Fidelity Perinatal Simulation training within midwifery education. Copyright © 2017 Australian College of Midwives. Published by Elsevier Ltd. All rights reserved.

A precipitation-runoff model for simulating natural streamflow conditions in the Smith River watershed, Montana, water years 1996-2008

USGS Publications Warehouse

Chase, Katherine J.; Caldwell, Rodney R.; Stanley, Andrea K.

2014-01-01

This report documents the construction of a precipitation-runoff model for simulating natural streamflow in the Smith River watershed, Montana. This Precipitation-Runoff Modeling System model, constructed in cooperation with the Meagher County Conservation District, can be used to examine the general hydrologic framework of the Smith River watershed, including quantification of precipitation, evapotranspiration, and streamflow; partitioning of streamflow between surface runoff and subsurface flow; and quantifying contributions to streamflow from several parts of the watershed. The model was constructed by using spatial datasets describing watershed topography, the streams, and the hydrologic characteristics of the basin soils and vegetation. Time-series data (daily total precipitation, and daily minimum and maximum temperature) were input to the model to simulate daily streamflow. The model was calibrated for water years 2002–2007 and evaluated for water years 1996–2001. Though water year 2008 was included in the study period to evaluate water-budget components, calibration and evaluation data were unavailable for that year. During the calibration and evaluation periods, simulated-natural flow values were compared to reconstructed-natural streamflow data. These reconstructed-natural streamflow data were calculated by adding Bureau of Reclamation’s depletions data to the observed streamflows. Reconstructed-natural streamflows represent estimates of streamflows for water years 1996–2007 assuming there was no agricultural water-resources development in the watershed. Additional calibration targets were basin mean monthly solar radiation and potential evapotranspiration. The model estimated the hydrologic processes in the Smith River watershed during the calibration and evaluation periods. Simulated-natural mean annual and mean monthly flows generally were the same or higher than the reconstructed-natural streamflow values during the calibration period, whereas

[Numerical simulation of the effect of virtual stent release pose on the expansion results].

PubMed

Li, Jing; Peng, Kun; Cui, Xinyang; Fu, Wenyu; Qiao, Aike

2018-04-01

The current finite element analysis of vascular stent expansion does not take into account the effect of the stent release pose on the expansion results. In this study, stent and vessel model were established by Pro/E. Five kinds of finite element assembly models were constructed by ABAQUS, including 0 degree without eccentricity model, 3 degree without eccentricity model, 5 degree without eccentricity model, 0 degree axial eccentricity model and 0 degree radial eccentricity model. These models were divided into two groups of experiments for numerical simulation with respect to angle and eccentricity. The mechanical parameters such as foreshortening rate, radial recoil rate and dog boning rate were calculated. The influence of angle and eccentricity on the numerical simulation was obtained by comparative analysis. Calculation results showed that the residual stenosis rates were 38.3%, 38.4%, 38.4%, 35.7% and 38.2% respectively for the 5 models. The results indicate that the pose has less effect on the numerical simulation results so that it can be neglected when the accuracy of the result is not highly required, and the basic model as 0 degree without eccentricity model is feasible for numerical simulation.

[3D Virtual Reality Laparoscopic Simulation in Surgical Education - Results of a Pilot Study].

PubMed

Kneist, W; Huber, T; Paschold, M; Lang, H

2016-06-01

The use of three-dimensional imaging in laparoscopy is a growing issue and has led to 3D systems in laparoscopic simulation. Studies on box trainers have shown differing results concerning the benefit of 3D imaging. There are currently no studies analysing 3D imaging in virtual reality laparoscopy (VRL). Five surgical fellows, 10 surgical residents and 29 undergraduate medical students performed abstract and procedural tasks on a VRL simulator using conventional 2D and 3D imaging in a randomised order. No significant differences between the two imaging systems were shown for students or medical professionals. Participants who preferred three-dimensional imaging showed significantly better results in 2D as wells as in 3D imaging. First results on three-dimensional imaging on box trainers showed different results. Some studies resulted in an advantage of 3D imaging for laparoscopic novices. This study did not confirm the superiority of 3D imaging over conventional 2D imaging in a VRL simulator. In the present study on 3D imaging on a VRL simulator there was no significant advantage for 3D imaging compared to conventional 2D imaging. Georg Thieme Verlag KG Stuttgart · New York.

Desktop Modeling and Simulation: Parsimonious, yet Effective Discrete-Event Simulation Analysis

NASA Technical Reports Server (NTRS)

Bradley, James R.

2012-01-01

This paper evaluates how quickly students can be trained to construct useful discrete-event simulation models using Excel The typical supply chain used by many large national retailers is described, and an Excel-based simulation model is constructed of it The set of programming and simulation skills required for development of that model are then determined we conclude that six hours of training are required to teach the skills to MBA students . The simulation presented here contains all fundamental functionallty of a simulation model, and so our result holds for any discrete-event simulation model. We argue therefore that Industry workers with the same technical skill set as students having completed one year in an MBA program can be quickly trained to construct simulation models. This result gives credence to the efficacy of Desktop Modeling and Simulation whereby simulation analyses can be quickly developed, run, and analyzed with widely available software, namely Excel.

From single Debye-Hückel chains to polyelectrolyte solutions: Simulation results

NASA Astrophysics Data System (ADS)

Kremer, Kurt

1996-03-01

This lecture will present results from simulations of single weakly charged flexible chains, where the electrostatic part of the interaction is modeled by a Debye-Hückel potential,( with U. Micka, IFF, Forschungszentrum Jülich, 52425 Jülich, Germany) as well as simulations of polyelectrolyte solutions, where the counterions are explicitly taken into account( with M. J. Stevens, Sandia Nat. Lab., Albuquerque, NM 87185-1111) ( M. J. Stevens, K. Kremer, JCP 103), 1669 (1995). The first set of the simulations is meant to clear a recent contoversy on the dependency of the persistence length LP on the screening length Γ. While the analytic theories give Lp ~ Γ^x with either x=1 or x=2, the simulations find for all experimentally accessible chain lengths a varying exponent, which is significantly smaller than 1. This causes serious doubts on the applicability of this model for weakly charged polyelectrolytes in general. The second part deals with strongly charged flexible polyelectrolytes in salt free solution. These simulations are performed for multichain systems. The full Coulomb interactions of the monomers and counterions are treated explicitly. Experimental measurements of the osmotic pressure and the structure factor are reproduced and extended. The simulations reveal a new picture of the chain structure based on calculations of the structure factor, persistence length, end-to-end distance, etc. Even at very low density, the chains show significant bending. Furthermore, the chains contract significantly before they start to overlap. We also show that counterion condensation dramatically alters the chain structure, even for a good solvent backbone.

CHARMM-GUI 10 Years for Biomolecular Modeling and Simulation

PubMed Central

Jo, Sunhwan; Cheng, Xi; Lee, Jumin; Kim, Seonghoon; Park, Sang-Jun; Patel, Dhilon S.; Beaven, Andrew H.; Lee, Kyu Il; Rui, Huan; Roux, Benoît; MacKerell, Alexander D.; Klauda, Jeffrey B.; Qi, Yifei

2017-01-01

CHARMM-GUI, http://www.charmm-gui.org, is a web-based graphical user interface that prepares complex biomolecular systems for molecular simulations. CHARMM-GUI creates input files for a number of programs including CHARMM, NAMD, GROMACS, AMBER, GENESIS, LAMMPS, Desmond, OpenMM, and CHARMM/OpenMM. Since its original development in 2006, CHARMM-GUI has been widely adopted for various purposes and now contains a number of different modules designed to set up a broad range of simulations: (1) PDB Reader & Manipulator, Glycan Reader, and Ligand Reader & Modeler for reading and modifying molecules; (2) Quick MD Simulator, Membrane Builder, Nanodisc Builder, HMMM Builder, Monolayer Builder, Micelle Builder, and Hex Phase Builder for building all-atom simulation systems in various environments; (3) PACE CG Builder and Martini Maker for building coarse-grained simulation systems; (4) DEER Facilitator and MDFF/xMDFF Utilizer for experimentally guided simulations; (5) Implicit Solvent Modeler, PBEQ-Solver, and GCMC/BD Ion Simulator for implicit solvent related calculations; (6) Ligand Binder for ligand solvation and binding free energy simulations; and (7) Drude Prepper for preparation of simulations with the CHARMM Drude polarizable force field. Recently, new modules have been integrated into CHARMM-GUI, such as Glycolipid Modeler for generation of various glycolipid structures, and LPS Modeler for generation of lipopolysaccharide structures from various Gram-negative bacteria. These new features together with existing modules are expected to facilitate advanced molecular modeling and simulation thereby leading to an improved understanding of the molecular details of the structure and dynamics of complex biomolecular systems. Here, we briefly review these capabilities and discuss potential future directions in the CHARMM-GUI development project. PMID:27862047

CHARMM-GUI 10 years for biomolecular modeling and simulation.

PubMed

Jo, Sunhwan; Cheng, Xi; Lee, Jumin; Kim, Seonghoon; Park, Sang-Jun; Patel, Dhilon S; Beaven, Andrew H; Lee, Kyu Il; Rui, Huan; Park, Soohyung; Lee, Hui Sun; Roux, Benoît; MacKerell, Alexander D; Klauda, Jeffrey B; Qi, Yifei; Im, Wonpil

2017-06-05

CHARMM-GUI, http://www.charmm-gui.org, is a web-based graphical user interface that prepares complex biomolecular systems for molecular simulations. CHARMM-GUI creates input files for a number of programs including CHARMM, NAMD, GROMACS, AMBER, GENESIS, LAMMPS, Desmond, OpenMM, and CHARMM/OpenMM. Since its original development in 2006, CHARMM-GUI has been widely adopted for various purposes and now contains a number of different modules designed to set up a broad range of simulations: (1) PDB Reader & Manipulator, Glycan Reader, and Ligand Reader & Modeler for reading and modifying molecules; (2) Quick MD Simulator, Membrane Builder, Nanodisc Builder, HMMM Builder, Monolayer Builder, Micelle Builder, and Hex Phase Builder for building all-atom simulation systems in various environments; (3) PACE CG Builder and Martini Maker for building coarse-grained simulation systems; (4) DEER Facilitator and MDFF/xMDFF Utilizer for experimentally guided simulations; (5) Implicit Solvent Modeler, PBEQ-Solver, and GCMC/BD Ion Simulator for implicit solvent related calculations; (6) Ligand Binder for ligand solvation and binding free energy simulations; and (7) Drude Prepper for preparation of simulations with the CHARMM Drude polarizable force field. Recently, new modules have been integrated into CHARMM-GUI, such as Glycolipid Modeler for generation of various glycolipid structures, and LPS Modeler for generation of lipopolysaccharide structures from various Gram-negative bacteria. These new features together with existing modules are expected to facilitate advanced molecular modeling and simulation thereby leading to an improved understanding of the structure and dynamics of complex biomolecular systems. Here, we briefly review these capabilities and discuss potential future directions in the CHARMM-GUI development project. © 2016 Wiley Periodicals, Inc. © 2016 Wiley Periodicals, Inc.

DoD Simulations: Improved Assessment Procedures Would Increase the Credibility of Results.

DTIC Science & Technology

1987-12-01

Carmonette Designed about 30 years ago, the Carmonette is a combined-arms combat model that simulates small-unit, ground combat involving the actions ...duels, its proper use is for larger engagements of combined-arms actions in which weapon-to- weapon data are used as input. The focus of the Carmonette...their contribution to the force, and their costs in personnel and funds. Its purpose is to assist in the selection of a preferred course of action to meet

HEBS and Binary 1-sinc masks simulations, HCIT experiments and results

NASA Technical Reports Server (NTRS)

Balasubramanian, Bala K.; Hoppe, Dan; Wilson, Dan; Echternach, Pierre; Trauger, John; Halverson, Peter; Niessner, Al; Shi, Fang; Lowman, Andrew

2005-01-01

Based on preliminary experiments and results with a binary 1-sinc mask in the HCIT early in August 2004, we planned for a detailed experiment to compare the performance of HEBS and Binary masks under nearly identical conditions in the HCIT. This report details the design and fabrication of the masks, simulated predictions, and experimental results.

Results of computer calculations for a simulated distribution of kidney cells

NASA Technical Reports Server (NTRS)

Micale, F. J.

1985-01-01

The results of computer calculations for a simulated distribution of kidney cells are given. The calculations were made for different values of electroosmotic flow, U sub o, and the ratio of sample diameter to channel diameter, R.

Analysis procedures and subjective flight results of a simulator validation and cue fidelity experiment

NASA Technical Reports Server (NTRS)

Carr, Peter C.; Mckissick, Burnell T.

1988-01-01

A joint experiment to investigate simulator validation and cue fidelity was conducted by the Dryden Flight Research Facility of NASA Ames Research Center (Ames-Dryden) and NASA Langley Research Center. The primary objective was to validate the use of a closed-loop pilot-vehicle mathematical model as an analytical tool for optimizing the tradeoff between simulator fidelity requirements and simulator cost. The validation process includes comparing model predictions with simulation and flight test results to evaluate various hypotheses for differences in motion and visual cues and information transfer. A group of five pilots flew air-to-air tracking maneuvers in the Langley differential maneuvering simulator and visual motion simulator and in an F-14 aircraft at Ames-Dryden. The simulators used motion and visual cueing devices including a g-seat, a helmet loader, wide field-of-view horizon, and a motion base platform.

UAHuntsville and NASA-MSFC Heliophysics REU: Year One Strategy and Results

NASA Astrophysics Data System (ADS)

Farid, S.; Heerikhuisen, J.; Winebarger, A. R.

2012-12-01

Scientists from the University of Alabama in Huntsville and NASA Marshall Space Fight Center (MSFC) received a 3-year National Science Foundation (NSF) award to create a unique Heliophysics Research Experience for Undergraduates (REU). For 10 weeks, 10 undergraduate students engaged in cutting edge heliophysics research with NASA or UAHuntsville astrophysicists specializing in research from the solar interior to the heliopause. Research projects included theory, modeling, computer simulations, data analysis and instrument design. The primary objectives of this REU are to 1.) increase minority participation in science, technology and mathematics (STEM) fields in general, and heliophysics in particular, and 2.) decrease the STEM attrition rate in first and second year students. This REU is unique because of our focus on recruiting talented students that may not have otherwise participated in an REU. In addition to the usual criteria of most REUs, consideration of need was also given to those students who were sophomores, students with little or no previous research experience, those from small or non-PhD granting institutions, students with less than average GPA, minorities, women, etc. In this poster, we review the effectiveness of the first year strategy. We evaluate the recruitment and application process, mentor placement, living and working arrangements, introductory tutorials, and merit of final research projects. We present modifications for next year's effort, and make suggestions to similar REU programs.

Marvel-ous Dwarfs: Results from Four Heroically Large Simulated Volumes of Dwarf Galaxies

NASA Astrophysics Data System (ADS)

Munshi, Ferah; Brooks, Alyson; Weisz, Daniel; Bellovary, Jillian; Christensen, Charlotte

2018-01-01

We present results from high resolution, fully cosmological simulations of cosmic sheets that contain many dwarf galaxies. Together, they create the largest collection of simulated dwarf galaxies to date, with z=0 stellar masses comparable to the LMC or smaller. In total, we have simulated almost 100 luminous dwarf galaxies, forming a sample of simulated dwarfs which span a wide range of physical (stellar and halo mass) and evolutionary properties (merger history). We show how they can be calibrated against a wealth of observations of nearby galaxies including star formation histories, HI masses and kinematics, as well as stellar metallicities. We present preliminary results answering the following key questions: What is the slope of the stellar mass function at extremely low masses? Do halos with HI and no stars exist? What is the scatter in the stellar to halo mass relationship as a function of dwarf mass? What drives the scatter? With this large suite, we are beginning to statistically characterize dwarf galaxies and identify the types and numbers of outliers to expect.

Prediction Markets and Beliefs about Climate: Results from Agent-Based Simulations

NASA Astrophysics Data System (ADS)

Gilligan, J. M.; John, N. J.; van der Linden, M.

2015-12-01

Climate scientists have long been frustrated by persistent doubts a large portion of the public expresses toward the scientific consensus about anthropogenic global warming. The political and ideological polarization of this doubt led Vandenbergh, Raimi, and Gilligan [1] to propose that prediction markets for climate change might influence the opinions of those who mistrust the scientific community but do trust the power of markets.We have developed an agent-based simulation of a climate prediction market in which traders buy and sell future contracts that will pay off at some future year with a value that depends on the global average temperature at that time. The traders form a heterogeneous population with different ideological positions, different beliefs about anthropogenic global warming, and different degrees of risk aversion. We also vary characteristics of the market, including the topology of social networks among the traders, the number of traders, and the completeness of the market. Traders adjust their beliefs about climate according to the gains and losses they and other traders in their social network experience. This model predicts that if global temperature is predominantly driven by greenhouse gas concentrations, prediction markets will cause traders' beliefs to converge toward correctly accepting anthropogenic warming as real. This convergence is largely independent of the structure of the market and the characteristics of the population of traders. However, it may take considerable time for beliefs to converge. Conversely, if temperature does not depend on greenhouse gases, the model predicts that traders' beliefs will not converge. We will discuss the policy-relevance of these results and more generally, the use of agent-based market simulations for policy analysis regarding climate change, seasonal agricultural weather forecasts, and other applications.[1] MP Vandenbergh, KT Raimi, & JM Gilligan. UCLA Law Rev. 61, 1962 (2014).

Results from a limited area mesoscale numerical simulation for 10 April 1979

NASA Technical Reports Server (NTRS)

Kalb, M. W.

1985-01-01

Results are presented from a nine-hour limited area fine mesh (35-km) mesoscale model simulation initialized with SESAME-AVE I radiosonde data for Apr. 10, 1979 at 2100 GMT. Emphasis is on the diagnosis of mesoscale structure in the mass and precipitation fields. Along the Texas/Oklahoma border, independent of the short wave, convective precipitation formed several hours into the simulation and was organized into a narrow band suggestive of the observed April 10 squall line.

Pushing precipitation to the extremes in distributed experiments: Recommendations for simulating wet and dry years

USGS Publications Warehouse

Knapp, Alan K.; Avolio, Meghan L.; Beier, Claus; Carroll, Charles J.W.; Collins, Scott L.; Dukes, Jeffrey S.; Fraser, Lauchlan H.; Griffin-Nolan, Robert J.; Hoover, David L.; Jentsch, Anke; Loik, Michael E.; Phillips, Richard P.; Post, Alison K.; Sala, Osvaldo E.; Slette, Ingrid J.; Yahdjian, Laura; Smith, Melinda D.

2017-01-01

Intensification of the global hydrological cycle, ranging from larger individual precipitation events to more extreme multiyear droughts, has the potential to cause widespread alterations in ecosystem structure and function. With evidence that the incidence of extreme precipitation years (defined statistically from historical precipitation records) is increasing, there is a clear need to identify ecosystems that are most vulnerable to these changes and understand why some ecosystems are more sensitive to extremes than others. To date, opportunistic studies of naturally occurring extreme precipitation years, combined with results from a relatively small number of experiments, have provided limited mechanistic understanding of differences in ecosystem sensitivity, suggesting that new approaches are needed. Coordinated distributed experiments (CDEs) arrayed across multiple ecosystem types and focused on water can enhance our understanding of differential ecosystem sensitivity to precipitation extremes, but there are many design challenges to overcome (e.g., cost, comparability, standardization). Here, we evaluate contemporary experimental approaches for manipulating precipitation under field conditions to inform the design of ‘Drought-Net’, a relatively low-cost CDE that simulates extreme precipitation years. A common method for imposing both dry and wet years is to alter each ambient precipitation event. We endorse this approach for imposing extreme precipitation years because it simultaneously alters other precipitation characteristics (i.e., event size) consistent with natural precipitation patterns. However, we do not advocate applying identical treatment levels at all sites – a common approach to standardization in CDEs. This is because precipitation variability varies >fivefold globally resulting in a wide range of ecosystem-specific thresholds for defining extreme precipitation years. For CDEs focused on precipitation extremes, treatments should be based

Pushing precipitation to the extremes in distributed experiments: recommendations for simulating wet and dry years.

PubMed

Knapp, Alan K; Avolio, Meghan L; Beier, Claus; Carroll, Charles J W; Collins, Scott L; Dukes, Jeffrey S; Fraser, Lauchlan H; Griffin-Nolan, Robert J; Hoover, David L; Jentsch, Anke; Loik, Michael E; Phillips, Richard P; Post, Alison K; Sala, Osvaldo E; Slette, Ingrid J; Yahdjian, Laura; Smith, Melinda D

2017-05-01

Intensification of the global hydrological cycle, ranging from larger individual precipitation events to more extreme multiyear droughts, has the potential to cause widespread alterations in ecosystem structure and function. With evidence that the incidence of extreme precipitation years (defined statistically from historical precipitation records) is increasing, there is a clear need to identify ecosystems that are most vulnerable to these changes and understand why some ecosystems are more sensitive to extremes than others. To date, opportunistic studies of naturally occurring extreme precipitation years, combined with results from a relatively small number of experiments, have provided limited mechanistic understanding of differences in ecosystem sensitivity, suggesting that new approaches are needed. Coordinated distributed experiments (CDEs) arrayed across multiple ecosystem types and focused on water can enhance our understanding of differential ecosystem sensitivity to precipitation extremes, but there are many design challenges to overcome (e.g., cost, comparability, standardization). Here, we evaluate contemporary experimental approaches for manipulating precipitation under field conditions to inform the design of 'Drought-Net', a relatively low-cost CDE that simulates extreme precipitation years. A common method for imposing both dry and wet years is to alter each ambient precipitation event. We endorse this approach for imposing extreme precipitation years because it simultaneously alters other precipitation characteristics (i.e., event size) consistent with natural precipitation patterns. However, we do not advocate applying identical treatment levels at all sites - a common approach to standardization in CDEs. This is because precipitation variability varies >fivefold globally resulting in a wide range of ecosystem-specific thresholds for defining extreme precipitation years. For CDEs focused on precipitation extremes, treatments should be based on

Results from teleoperated free-flying spacecraft simulations in the Martin Marietta space operations simulator lab

NASA Technical Reports Server (NTRS)

Hartley, Craig S.

1990-01-01

To augment the capabilities of the Space Transportation System, NASA has funded studies and developed programs aimed at developing reusable, remotely piloted spacecraft and satellite servicing systems capable of delivering, retrieving, and servicing payloads at altitudes and inclinations beyond the reach of the present Shuttle Orbiters. Since the mid 1970's, researchers at the Martin Marietta Astronautics Group Space Operations Simulation (SOS) Laboratory have been engaged in investigations of remotely piloted and supervised autonomous spacecraft operations. These investigations were based on high fidelity, real-time simulations and have covered a wide range of human factors issues related to controllability. Among these are: (1) mission conditions, including thruster plume impingements and signal time delays; (2) vehicle performance variables, including control authority, control harmony, minimum impulse, and cross coupling of accelerations; (3) maneuvering task requirements such as target distance and dynamics; (4) control parameters including various control modes and rate/displacement deadbands; and (5) display parameters involving camera placement and function, visual aids, and presentation of operational feedback from the spacecraft. This presentation includes a brief description of the capabilities of the SOS Lab to simulate real-time free-flyer operations using live video, advanced technology ground and on-orbit workstations, and sophisticated computer models of on-orbit spacecraft behavior. Sample results from human factors studies in the five categories cited above are provided.

LVC Architecture Roadmap Implementation - Results of the First Two Years

DTIC Science & Technology

2012-03-01

NOTES Presented at the Simulation Interoperability Standards Organization?s (SISO) Spring Simulation Interoperability Workshop ( SIW ), 26-30 March...presented at the semi-annual Simulation Interoperability Workshops ( SIWs ) and the annual Interservice/Industry Training, Simulation & Education Conference...I/ITSEC), as well as other venues. For example, a full-day workshop on the initial progress of the effort was conducted at the 2010 Spring SIW [2

Novel approach for beacon formation through simulated turbulence: initial lab-test results

NASA Astrophysics Data System (ADS)

Khizhnyak, A.; Markov, V.; Tomov, I.; Wu, F.

2010-02-01

In this paper we report the results of the analysis and experimental modeling of the target-in-the-loop (TIL) approach that is used to form a localized beacon for a laser beam propagating through turbulent atmosphere. The analogy between the TIL system and the laser cavity has been used here to simulate the process shaping the laser beacon on a remote image-resolved target with rough surface. The TIL breadboard was integrated and used for laboratory modeling of the proposed approach. This breadboard allowed to simulate the TIL arrangement with a rough-surface target and laser beam propagation through the turbulent atmospheric layer. Here we present the initial results of the performed studies.

Training auscultatory skills: computer simulated heart sounds or additional bedside training? A randomized trial on third-year medical students

PubMed Central

2010-01-01

Background The present study compares the value of additional use of computer simulated heart sounds, to conventional bedside auscultation training, on the cardiac auscultation skills of 3rd year medical students at Oslo University Medical School. Methods In addition to their usual curriculum courses, groups of seven students each were randomized to receive four hours of additional auscultation training either employing a computer simulator system or adding on more conventional bedside training. Cardiac auscultation skills were afterwards tested using live patients. Each student gave a written description of the auscultation findings in four selected patients, and was rewarded from 0-10 points for each patient. Differences between the two study groups were evaluated using student's t-test. Results At the auscultation test no significant difference in mean score was found between the students who had used additional computer based sound simulation compared to additional bedside training. Conclusions Students at an early stage of their cardiology training demonstrated equal performance of cardiac auscultation whether they had received an additional short auscultation course based on computer simulated training, or had had additional bedside training. PMID:20082701

Free Energy Landscape of Protein-Protein Encounter Resulting from Brownian Dynamics Simulations of Barnase:Barstar.

PubMed

Spaar, Alexander; Helms, Volkhard

2005-07-01

Over the past years Brownian dynamics (BD) simulations have been proven to be a suitable tool for the analysis of protein-protein association. The computed rates and relative trends for protein mutants and different ionic strength are generally in good agreement with experimental results, e.g. see ref 1. By design, BD simulations correspond to an intensive sampling over energetically favorable states, rather than to a systematic sampling over all possible states which is feasible only at rather low resolution. On the example of barnase and barstar, a well characterized model system of electrostatically steered diffusional encounter, we report here the computation of the 6-dimensional free energy landscape for the encounter process of two proteins by a novel, careful analysis of the trajectories from BD simulations. The aim of these studies was the clarification of the encounter state. Along the trajectories, the individual positions and orientations of one protein (relative to the other) are recorded and stored in so-called occupancy maps. Since the number of simulated trajectories is sufficiently high, these occupancy maps can be interpreted as a probability distribution which allows the calculation of the entropy landscape by the use of a locally defined entropy function. Additionally, the configuration dependent electrostatic and desolvation energies are recorded in separate maps. The free energy landscape of protein-protein encounter is finally obtained by summing the energy and entropy contributions. In the free energy profile along the reaction path, which is defined as the path along the minima in the free energy landscape, a minimum shows up suggesting this to be used as the definition of the encounter state. This minimum describes a state of reduced diffusion velocity where the electrostatic attraction is compensated by the repulsion due to the unfavorable desolvation of the charged residues and the entropy loss due to the increasing restriction of the

Modelled air pollution levels versus EC air quality legislation - results from high resolution simulation.

PubMed

Chervenkov, Hristo

2013-12-01

An appropriate method for evaluating the air quality of a certain area is to contrast the actual air pollution levels to the critical ones, prescribed in the legislative standards. The application of numerical simulation models for assessing the real air quality status is allowed by the legislation of the European Community (EC). This approach is preferable, especially when the area of interest is relatively big and/or the network of measurement stations is sparse, and the available observational data are scarce, respectively. Such method is very efficient for similar assessment studies due to continuous spatio-temporal coverage of the obtained results. In the study the values of the concentration of the harmful substances sulphur dioxide, (SO2), nitrogen dioxide (NO2), particulate matter - coarse (PM10) and fine (PM2.5) fraction, ozone (O3), carbon monoxide (CO) and ammonia (NH3) in the surface layer obtained from modelling simulations with resolution 10 km on hourly bases are taken to calculate the necessary statistical quantities which are used for comparison with the corresponding critical levels, prescribed in the EC directives. For part of them (PM2.5, CO and NH3) this is done for first time with such resolution. The computational grid covers Bulgaria entirely and some surrounding territories and the calculations are made for every year in the period 1991-2000. The averaged over the whole time slice results can be treated as representative for the air quality situation of the last decade of the former century.

Dark Energy Survey Year 1 results: curved-sky weak lensing mass map

NASA Astrophysics Data System (ADS)

Chang, C.; Pujol, A.; Mawdsley, B.; Bacon, D.; Elvin-Poole, J.; Melchior, P.; Kovács, A.; Jain, B.; Leistedt, B.; Giannantonio, T.; Alarcon, A.; Baxter, E.; Bechtol, K.; Becker, M. R.; Benoit-Lévy, A.; Bernstein, G. M.; Bonnett, C.; Busha, M. T.; Rosell, A. Carnero; Castander, F. J.; Cawthon, R.; da Costa, L. N.; Davis, C.; De Vicente, J.; DeRose, J.; Drlica-Wagner, A.; Fosalba, P.; Gatti, M.; Gaztanaga, E.; Gruen, D.; Gschwend, J.; Hartley, W. G.; Hoyle, B.; Huff, E. M.; Jarvis, M.; Jeffrey, N.; Kacprzak, T.; Lin, H.; MacCrann, N.; Maia, M. A. G.; Ogando, R. L. C.; Prat, J.; Rau, M. M.; Rollins, R. P.; Roodman, A.; Rozo, E.; Rykoff, E. S.; Samuroff, S.; Sánchez, C.; Sevilla-Noarbe, I.; Sheldon, E.; Troxel, M. A.; Varga, T. N.; Vielzeuf, P.; Vikram, V.; Wechsler, R. H.; Zuntz, J.; Abbott, T. M. C.; Abdalla, F. B.; Allam, S.; Annis, J.; Bertin, E.; Brooks, D.; Buckley-Geer, E.; Burke, D. L.; Kind, M. Carrasco; Carretero, J.; Crocce, M.; Cunha, C. E.; D'Andrea, C. B.; Desai, S.; Diehl, H. T.; Dietrich, J. P.; Doel, P.; Estrada, J.; Neto, A. Fausti; Fernandez, E.; Flaugher, B.; Frieman, J.; García-Bellido, J.; Gruendl, R. A.; Gutierrez, G.; Honscheid, K.; James, D. J.; Jeltema, T.; Johnson, M. W. G.; Johnson, M. D.; Kent, S.; Kirk, D.; Krause, E.; Kuehn, K.; Kuhlmann, S.; Lahav, O.; Li, T. S.; Lima, M.; March, M.; Martini, P.; Menanteau, F.; Miquel, R.; Mohr, J. J.; Neilsen, E.; Nichol, R. C.; Petravick, D.; Plazas, A. A.; Romer, A. K.; Sako, M.; Sanchez, E.; Scarpine, V.; Schubnell, M.; Smith, M.; Smith, R. C.; Soares-Santos, M.; Sobreira, F.; Suchyta, E.; Tarle, G.; Thomas, D.; Tucker, D. L.; Walker, A. R.; Wester, W.; Zhang, Y.

2018-04-01

We construct the largest curved-sky galaxy weak lensing mass map to date from the DES first-year (DES Y1) data. The map, about 10 times larger than the previous work, is constructed over a contiguous ≈1500 deg2, covering a comoving volume of ≈10 Gpc3. The effects of masking, sampling, and noise are tested using simulations. We generate weak lensing maps from two DES Y1 shear catalogues, METACALIBRATION and IM3SHAPE, with sources at redshift 0.2 < z < 1.3, and in each of four bins in this range. In the highest signal-to-noise map, the ratio between the mean signal to noise in the E-mode map and the B-mode map is ˜1.5 (˜2) when smoothed with a Gaussian filter of σG = 30 (80) arcmin. The second and third moments of the convergence κ in the maps are in agreement with simulations. We also find no significant correlation of κ with maps of potential systematic contaminants. Finally, we demonstrate two applications of the mass maps: (1) cross-correlation

Results of a Flight Simulation Software Methods Survey

NASA Technical Reports Server (NTRS)

Jackson, E. Bruce

1995-01-01

A ten-page questionnaire was mailed to members of the AIAA Flight Simulation Technical Committee in the spring of 1994. The survey inquired about various aspects of developing and maintaining flight simulation software, as well as a few questions dealing with characterization of each facility. As of this report, 19 completed surveys (out of 74 sent out) have been received. This paper summarizes those responses.

Plasma Drifts in the Intermediate Magnetosphere: Simulation Results

NASA Astrophysics Data System (ADS)

Lyon, J.; Zhang, B.

2016-12-01

One of the outstanding questions about the inner magnetosphere dynamics is how the ring current is populated. It is not clear how much is due to a general injection over longer time and spatial scales and how much due to more bursty events. One of the major uncertainties is the behavior of the plasma in the intermediate magnetosphere: the region where the magnetosphere changes from being tail-like to one where the dipole field dominates. This is also the region where physically the plasma behavior changes from MHD-like in the tail to one dominated by particle drifts in the inner magnetosphere. No of the current simulation models self-consistently handle the region where drifts are important but not dominant. We have recently developed a version of the multi-fluid LFM code that can self-consistently handle this situation. The drifts are modeled in a fashion similar to the Rice Convection Model in that a number of energy "channels" are explicitly simulated. However, the method is not limited to the "slow flow" region and both diamagnetic and inertial drifts are included. We present results from a number of idealized cases of the global magnetosphere interacting with a southward turning of the IMF. We discuss the relative importance of general convection and bursty flows to the transport of particles and energy across this region.

Effect of simulator training on fitness-to-drive after stroke: a 5-year follow-up of a randomized controlled trial.

PubMed

Devos, Hannes; Akinwuntan, Abiodun Emmanuel; Nieuwboer, Alice; Ringoot, Isabelle; Van Berghen, Karen; Tant, Mark; Kiekens, Carlotte; De Weerdt, Willy

2010-01-01

No long-term studies have been reported on the effect of training programs on driving after stroke. The authors' primary aim was to determine the effect of simulator versus cognitive rehabilitation therapy on fitness-to-drive at 5 years poststroke. A second aim was to investigate differences in clinical characteristics between stroke survivors who resumed and stopped driving. In a previously reported randomized controlled trial, 83 stroke survivors received 15 hours of simulator training (n = 42) or cognitive therapy (n = 41). In this 5-year follow-up study, 61 participants were reassessed. Fitness-to-drive decisions were obtained from medical, visual, neuropsychological, and on-road tests; 44 participants (simulator group, n = 21; cognitive group, n = 23) completed all assessments. The primary outcome measures were fitness-to-drive decision and current driving status. The authors found that 5 years after stroke, 18 of 30 participants (60%) in the simulator group were considered fit to drive, compared with 15 of 31 (48%) in the cognitive group (P = .36); 34 of 61 (56%) participants were driving. Current drivers were younger (P = .04), had higher Barthel scores (P = .008), had less comorbidity (P = .01), and were less severely depressed (P = .02) than those who gave up driving. The advantage of simulator-based driving training over cognitive rehabilitation therapy, evident at 6 months poststroke, had faded 5 years later. Poststroke drivers were younger and less severely affected and depressed than nondrivers.

Simulated root dynamics of a 160-year-old sugar maple (Acer saccharum Marsh.) tree with and without ozone exposure using the TREGRO model.

PubMed

Retzlaff, W. A.; Weinstein, D. A.; Laurence, J. A.; Gollands, B.

1996-01-01

Because of difficulties in directly assessing root responses of mature forest trees exposed to atmospheric pollutants, we have used the model TREGRO to analyze the effects of a 3- and a 10-year exposure to ozone (O(3)) on root dynamics of a simulated 160-year-old sugar maple (Acer saccharum Marsh.) tree. We used existing phenological, allometric, and growth data to parameterize TREGRO to produce a simulated 160-year-old tree. Simulations were based on literature values for sugar maple fine root production and senescence and the photosynthetic responses of sugar maple seedlings exposed to O(3) in open-top chambers. In the simulated 3-year exposure to O(3), 2 x ambient atmospheric O(3) concentrations reduced net carbon (C) gain of the 160-year-old tree. This reduction occurred in the C storage pools (total nonstructural carbohydrate, TNC), with most of the reduction occurring in coarse (woody) roots. Total fine root production and senescence were unaffected by the simulated 3-year exposure to O(3). However, extending the simulated O(3) exposure period to 10 years depleted the TNC pools of the coarse roots and reduced total fine root production. Similar reductions in TNC pools have been observed in forest-grown sugar maple trees exhibiting symptoms of stress. We conclude that modeling can aid in evaluating the belowground response of mature forest trees to atmospheric pollution stress and could indicate the potential for gradual deterioration of tree health under conditions of long-term stress, a situation similar to that underlying the decline of sugar maple trees.

ENSO effects on MLT diurnal tides: A 21 year reanalysis data-driven GAIA model simulation

NASA Astrophysics Data System (ADS)

Liu, Huixin; Sun, Yang-Yi; Miyoshi, Yasunobu; Jin, Hidekatsu

2017-05-01

Tidal responses to El Niño-Southern Oscillation (ENSO) in the mesosphere and lower thermosphere (MLT) are investigated for the first time using reanalysis data-driven simulations covering 21 years. The simulation is carried out with the Ground-to-topside Atmosphere-Ionosphere model for Aeronomy (GAIA) during 1996-2016, which covers nine ENSO events. ENSO impacts on diurnal tides at 100 km altitude are analyzed and cross-compared among temperature (T), zonal wind (U), and meridional wind (V), which reveals the following salient features: (1) Tidal response can differ significantly among T, U, and V in terms of magnitude and latitudinal structure, making detection of ENSO effects sensitive to the parameter used and the location of a ground station; (2) the nonmigrating DE3 tide in T and U shows a prominent hemisphere asymmetric response to La Niña, with an increase between 0° and 30°N and a decrease between 30° and 0°S. In contrast, DE3 in V exhibits no significant response; (3) the migrating DW1 enhances during El Niño in equatorial regions for T and U but in off-equatorial regions for V. As the first ENSO study based on reanalysis-driven simulations, GAIA's full set of tidal responses in T, U, and V provides us with a necessary global context to better understand and cross-compare observations during ENSO events. Comparisons with observations during the 1997-98 El Niño and 2010-11 La Niña reveal good agreement in both magnitude and timing. Comparisons with "free-run" WACCM simulations (T) show consistent results in nonmigrating tides DE2 and DE3 but differences in the migrating DW1 tide.

[Implementation results of emission standards of air pollutants for thermal power plants: a numerical simulation].

PubMed

Wang, Zhan-Shan; Pan, Li-Bo

2014-03-01

The emission inventory of air pollutants from the thermal power plants in the year of 2010 was set up. Based on the inventory, the air quality of the prediction scenarios by implementation of both 2003-version emission standard and the new emission standard were simulated using Models-3/CMAQ. The concentrations of NO2, SO2, and PM2.5, and the deposition of nitrogen and sulfur in the year of 2015 and 2020 were predicted to investigate the regional air quality improvement by the new emission standard. The results showed that the new emission standard could effectively improve the air quality in China. Compared with the implementation results of the 2003-version emission standard, by 2015 and 2020, the area with NO2 concentration higher than the emission standard would be reduced by 53.9% and 55.2%, the area with SO2 concentration higher than the emission standard would be reduced by 40.0%, the area with nitrogen deposition higher than 1.0 t x km(-2) would be reduced by 75.4% and 77.9%, and the area with sulfur deposition higher than 1.6 t x km(-2) would be reduced by 37.1% and 34.3%, respectively.

Propellant/material compatibility program and results: Ten-year milestones

NASA Technical Reports Server (NTRS)

Moran, C.; Bjorkland, R.

1982-01-01

The analyses and results of a test program to establish the effects of long term (10 years or more) contact of materials with earth-storable propellants for the purpose of designing chemical propulsion system components which are used for current as well as future planetary spacecraft are described. The period from the publication of JPL TM 33-779 IN 1976 through the testing accomplished in 1981 is covered. The following propellants are reported herein: hydrazine, monomethylhydrazine and nitrogen tetroxide. Materials included the following: aluminum alloys, corrosion resistant steels and a titanium alloy. The results of the testing of more than 80 specimens are included. Material ratings relative to the ten year milepost were assigned. Some evidence of propellant decomposition was found. Titanium is rated as acceptable for ten year applications. Aluminum and stainless steel alloys are also rated as acceptable with few restrictions.

Interannual variability of temperature over 50 years in the Bay of Biscay described by global simulations

NASA Astrophysics Data System (ADS)

Assassi, Charefeddine; Vandermeirsch, Frederic; Morel, Yves; Charria, Guillaume; Theetten, Sébastien; Dussin, Raphaël; Molines, Jean-Marc

2014-05-01

The aim of this study is to better understand the different overriding mechanisms that control the evolution of the temperature in the Bay of Biscay, through realistic simulations over a period of 50 years. Before performing and analyzing our own numerical experiments with a spatial resolution of 4 km, we compared two global simulations, ORCA-G70 and ORCA-GRD100 (¼° resolution) carried out from the ocean circulation model NEMO by the DRAKKAR group with inter-annual climatologies (WOA04, Levitus et al. 2005 and Bobyclim, Michel et al. 2009). Both simulations differ in their vertical resolution (46 levels in G70 and 75 levels in GRD100) and atmospheric forcings. The comparison of the two simulations shows an underestimation of the absolute temperature in GRD100 approximately 0.4°C in the first 300 meters for the entire period of the simulation (1958-2004) compared to G70, although the net air-sea heat flux is significantly higher in GRD100 (2.92 TW for GRD100 and 0.20 TW for G70). Several parameters can explain this apparent contradiction. On one hand, the wind is more intense in GRD100 and can contribute to the heat penetration on depth. On the other hand, the thermal balances at different depths show a great disparity between both simulations, especially in terms of advective transport. However, the temperature anomaly in the two global simulations is very close to observations (climatology) in the first 400 meters. The standard deviation is higher in the mixed layer (0.29°C for both simulations ORCA) and lower in the intermediate layers (0.15°C for G70 and to 0.13°C for GRD100). Moreover, the calculation of the surface linear trend of temperature in GRD100 (0.14°C.decade-1) is closer to the observations W0A04 (0.19°C.decade-1) while it is only (0.10°C.decade-1) in G70. The GRD100 simulation provides a better evolution than G70. These analysis confirm the suitability of the simulation GRD100 to drive a regional numerical experiment at higher resolution in

Quench simulation results for a 12-T twin-aperture dipole magnet

NASA Astrophysics Data System (ADS)

Cheng, Da; Salmi, Tiina; Xu, Qingjin; Peng, Quanling; Wang, Chengtao; Wang, Yingzhe; Kong, Ershuai; Zhang, Kai

2018-06-01

A 12-T twin-aperture subscale dipole magnet is being developed for SPPC pre-study at the Institute of High Energy Physics (IHEP). The magnet is comprised of 6 double-pancake coils which include 2 Nb3Sn coils and 4 NbTi coils. As the stored energy of the magnet is 0.452 MJ and the operation margin is only about 20% at 4.2 K, a quick and effective quench protection system is necessary during the test of this high field magnet. For the design of the quench protection system, attention was not only paid to the hotspot temperature and terminal voltage, but also the temperature gradient during the quench process due to the poor mechanical characteristics of the Nb3Sn cables. With the adiabatic analysis, numerical simulation and the finite element simulation, an optimized protection method is adopted, which contains a dump resistor and quench heaters. In this paper, the results of adiabatic analysis and quench simulation, such as current decay, hot-spot temperature and terminal voltage are presented in details.

Airflow Hazard Visualization for Helicopter Pilots: Flight Simulation Study Results

NASA Technical Reports Server (NTRS)

Aragon, Cecilia R.; Long, Kurtis R.

2005-01-01

Airflow hazards such as vortices or low level wind shear have been identified as a primary contributing factor in many helicopter accidents. US Navy ships generate airwakes over their decks, creating potentially hazardous conditions for shipboard rotorcraft launch and recovery. Recent sensor developments may enable the delivery of airwake data to the cockpit, where visualizing the hazard data may improve safety and possibly extend ship/helicopter operational envelopes. A prototype flight-deck airflow hazard visualization system was implemented on a high-fidelity rotorcraft flight dynamics simulator. Experienced helicopter pilots, including pilots from all five branches of the military, participated in a usability study of the system. Data was collected both objectively from the simulator and subjectively from post-test questionnaires. Results of the data analysis are presented, demonstrating a reduction in crash rate and other trends that illustrate the potential of airflow hazard visualization to improve flight safety.

Mechanics of Nanostructured Porous Silica Aerogel Resulting from Molecular Dynamics Simulations.

PubMed

Patil, Sandeep P; Rege, Ameya; Sagardas; Itskov, Mikhail; Markert, Bernd

2017-06-08

Silica aerogels are nanostructured, highly porous solids which have, compared to other soft materials, special mechanical properties, such as extremely low densities. In the present work, the mechanical properties of silica aerogels have been studied with molecular dynamics (MD) simulations. The aerogel model of 192 000 atoms was created with different densities by direct expansion of β-cristobalite and subjected to series of thermal treatments. Because of the high number of atoms and improved modeling procedure, the proposed model was more stable and showed significant improvement in the smoothness of the resulting stress-strain curves in comparison to previous models. Resulting Poisson's ratio values for silica aerogels lie between 0.18 and 0.21. The elasticity moduli display a power law dependence on the density, with the exponent estimated to be 3.25 ± 0.1. These results are in excellent agreement with reported experimental as well as computational values. Two different deformation scenarios have been discussed. Under tension, the low-density aerogels were more ductile while the denser ones behaved rather brittle. In the compression simulations of low-density aerogels, deformation occurred without significant increase in stress. However, for high densities, atoms offer a higher resistance to the deformation, resulting in a more stiff response and an early densification. The relationship between different mechanical parameters has been found in the cyclic loading simulations of silica aerogels with different densities. The residual strain grows linearly with the applied strain (≥0.16) and can be approximated by a phenomenological relation ϵ p = 1.09ϵ max - 0.12. The dissipation energy also varies with the compressive strain according to a power law with an exponent of 2.31 ± 0.07. Moreover, the tangent modulus under cyclic loading varies exponentially with the compressive strain. The results of the study pave the way toward multiscale modeling of silica

A finite element model of a six-year-old child for simulating pedestrian accidents.

PubMed

Meng, Yunzhu; Pak, Wansoo; Guleyupoglu, Berkan; Koya, Bharath; Gayzik, F Scott; Untaroiu, Costin D

2017-01-01

Child pedestrian protection deserves more attention in vehicle safety design since they are the most vulnerable road users who face the highest mortality rate. Pediatric Finite Element (FE) models could be used to simulate and understand the pedestrian injury mechanisms during crashes in order to mitigate them. Thus, the objective of the study was to develop a computationally efficient (simplified) six-year-old (6YO-PS) pedestrian FE model and validate it based on the latest published pediatric data. The 6YO-PS FE model was developed by morphing the existing GHBMC adult pedestrian model. Retrospective scan data were used to locally adjust the geometry as needed for accuracy. Component test simulations focused only the lower extremities and pelvis, which are the first body regions impacted during pedestrian accidents. Three-point bending test simulations were performed on the femur and tibia with adult material properties and then updated using child material properties. Pelvis impact and knee bending tests were also simulated. Finally, a series of pediatric Car-to-Pedestrian Collision (CPC) were simulated with pre-impact velocities ranging from 20km/h up to 60km/h. The bone models assigned pediatric material properties showed lower stiffness and a good match in terms of fracture force to the test data (less than 6% error). The pelvis impact force predicted by the child model showed a similar trend with test data. The whole pedestrian model was stable during CPC simulations and predicted common pedestrian injuries. Overall, the 6YO-PS FE model developed in this study showed good biofidelity at component level (lower extremity and pelvis) and stability in CPC simulations. While more validations would improve it, the current model could be used to investigate the lower limb injury mechanisms and in the prediction of the impact parameters as specified in regulatory testing protocols. Copyright © 2016 Elsevier Ltd. All rights reserved.

Numerical simulations of hydrothermal circulation resulting from basalt intrusions in a buried spreading center

USGS Publications Warehouse

Fisher, A.T.; Narasimhan, T.N.

1991-01-01

A two-dimensional, one by two-kilometer section through the seafloor was simulated with a numerical model to investigate coupled fluid and heat flow resulting from basalt intrusions in a buried spreading center. Boundary and initial conditions and physical properties of both sediments and basalt were constrained by field surveys and drilling in the Guaymas Basin, central Gulf of California. Parametric variations in these studies included sediment and basalt permeability, anisotropy in sediment permeability, and the size of heat sources. Faults were introduced through new intrusions both before and after cooling.Background heat input caused fluid convection at velocities ≤ 3 cm a−1 through shallow sediments. Eighty to ninety percent of the heat introduced at the base of the simulations exited through the upper, horizontal surface, even when the vertical boundaries were made permeable to fluid flow. The simulated injection of a 25–50 m thick basalt intrusion at a depth of 250 m resulted in about 10 yr of pore-fluid expulsion through the sea-floor in all cases, leaving the sediments above the intrusions strongly underpressured. A longer period of fluid recharge followed, sometimes accompanied by reductions in total seafloor heat output of 10% in comparison to pre-intrusion values. Additional discharge-recharge events were dispersed chaotically through the duration of the cooling period. These cycles in heat and fluid flow resulted from the response of the simulated system to a thermodynamic shock, the sudden emplacement of a large heat source, and not from mechanical displacement of sediments and pore fluids, which was not simulated.Water/rock mass ratios calculated from numerical simulations are in good agreement with geochemical estimates from materials recovered from the Guaymas Basin, assuming a bulk basalt permeability value of at least 10−17 m2/(10−2 mD). The addition of faults through intrusions and sediments in these simulations did not facilitate

Geometry and Simulation Results for a Gas Turbine Representative of the Energy Efficient Engine (EEE)

NASA Technical Reports Server (NTRS)

Claus, Russell W.; Beach, Tim; Turner, Mark; Hendricks, Eric S.

2015-01-01

This paper describes the geometry and simulation results of a gas-turbine engine based on the original EEE engine developed in the 1980s. While the EEE engine was never in production, the technology developed during the program underpins many of the current generation of gas turbine engines. This geometry is being explored as a potential multi-stage turbomachinery test case that may be used to develop technology for virtual full-engine simulation. Simulation results were used to test the validity of each component geometry representation. Results are compared to a zero-dimensional engine model developed from experimental data. The geometry is captured in a series of Initial Graphical Exchange Specification (IGES) files and is available on a supplemental DVD to this report.

High-Alpha Research Vehicle Lateral-Directional Control Law Description, Analyses, and Simulation Results

NASA Technical Reports Server (NTRS)

Davidson, John B.; Murphy, Patrick C.; Lallman, Frederick J.; Hoffler, Keith D.; Bacon, Barton J.

1998-01-01

This report contains a description of a lateral-directional control law designed for the NASA High-Alpha Research Vehicle (HARV). The HARV is a F/A-18 aircraft modified to include a research flight computer, spin chute, and thrust-vectoring in the pitch and yaw axes. Two separate design tools, CRAFT and Pseudo Controls, were integrated to synthesize the lateral-directional control law. This report contains a description of the lateral-directional control law, analyses, and nonlinear simulation (batch and piloted) results. Linear analysis results include closed-loop eigenvalues, stability margins, robustness to changes in various plant parameters, and servo-elastic frequency responses. Step time responses from nonlinear batch simulation are presented and compared to design guidelines. Piloted simulation task scenarios, task guidelines, and pilot subjective ratings for the various maneuvers are discussed. Linear analysis shows that the control law meets the stability margin guidelines and is robust to stability and control parameter changes. Nonlinear batch simulation analysis shows the control law exhibits good performance and meets most of the design guidelines over the entire range of angle-of-attack. This control law (designated NASA-1A) was flight tested during the Summer of 1994 at NASA Dryden Flight Research Center.

Magnetic Compression Experiment at General Fusion with Simulation Results

NASA Astrophysics Data System (ADS)

Dunlea, Carl; Khalzov, Ivan; Hirose, Akira; Xiao, Chijin; Fusion Team, General

2017-10-01

The magnetic compression experiment at GF was a repetitive non-destructive test to study plasma physics applicable to Magnetic Target Fusion compression. A spheromak compact torus (CT) is formed with a co-axial gun into a containment region with an hour-glass shaped inner flux conserver, and an insulating outer wall. External coil currents keep the CT off the outer wall (levitation) and then rapidly compress it inwards. The optimal external coil configuration greatly improved both the levitated CT lifetime and the rate of shots with good compressional flux conservation. As confirmed by spectrometer data, the improved levitation field profile reduced plasma impurity levels by suppressing the interaction between plasma and the insulating outer wall during the formation process. We developed an energy and toroidal flux conserving finite element axisymmetric MHD code to study CT formation and compression. The Braginskii MHD equations with anisotropic heat conduction were implemented. To simulate plasma / insulating wall interaction, we couple the vacuum field solution in the insulating region to the full MHD solution in the remainder of the domain. We see good agreement between simulation and experiment results. Partly funded by NSERC and MITACS Accelerate.

SRG110 Stirling Generator Dynamic Simulator Vibration Test Results and Analysis Correlation

NASA Technical Reports Server (NTRS)

Suarez, Vicente J.; Lewandowski, Edward J.; Callahan, John

2006-01-01

The U.S. Department of Energy (DOE), Lockheed Martin (LM), and NASA Glenn Research Center (GRC) have been developing the Stirling Radioisotope Generator (SRG110) for use as a power system for space science missions. The launch environment enveloping potential missions results in a random input spectrum that is significantly higher than historical RPS launch levels and is a challenge for designers. Analysis presented in prior work predicted that tailoring the compliance at the generator-spacecraft interface reduced the dynamic response of the system thereby allowing higher launch load input levels and expanding the range of potential generator missions. To confirm analytical predictions, a dynamic simulator representing the generator structure, Stirling convertors and heat sources was designed and built for testing with and without a compliant interface. Finite element analysis was performed to guide the generator simulator and compliant interface design so that test modes and frequencies were representative of the SRG110 generator. This paper presents the dynamic simulator design, the test setup and methodology, test article modes and frequencies and dynamic responses, and post-test analysis results. With the compliant interface, component responses to an input environment exceeding the SRG110 qualification level spectrum were all within design allowables. Post-test analysis included finite element model tuning to match test frequencies and random response analysis using the test input spectrum. Analytical results were in good overall agreement with the test results and confirmed previous predictions that the SRG110 power system may be considered for a broad range of potential missions, including those with demanding launch environments.

SRG110 Stirling Generator Dynamic Simulator Vibration Test Results and Analysis Correlation

NASA Technical Reports Server (NTRS)

Lewandowski, Edward J.; Suarez, Vicente J.; Goodnight, Thomas W.; Callahan, John

2007-01-01

The U.S. Department of Energy (DOE), Lockheed Martin (LM), and NASA Glenn Research Center (GRC) have been developing the Stirling Radioisotope Generator (SRG110) for use as a power system for space science missions. The launch environment enveloping potential missions results in a random input spectrum that is significantly higher than historical radioisotope power system (RPS) launch levels and is a challenge for designers. Analysis presented in prior work predicted that tailoring the compliance at the generator-spacecraft interface reduced the dynamic response of the system thereby allowing higher launch load input levels and expanding the range of potential generator missions. To confirm analytical predictions, a dynamic simulator representing the generator structure, Stirling convertors and heat sources were designed and built for testing with and without a compliant interface. Finite element analysis was performed to guide the generator simulator and compliant interface design so that test modes and frequencies were representative of the SRG110 generator. This paper presents the dynamic simulator design, the test setup and methodology, test article modes and frequencies and dynamic responses, and post-test analysis results. With the compliant interface, component responses to an input environment exceeding the SRG110 qualification level spectrum were all within design allowables. Post-test analysis included finite element model tuning to match test frequencies and random response analysis using the test input spectrum. Analytical results were in good overall agreement with the test results and confirmed previous predictions that the SRG110 power system may be considered for a broad range of potential missions, including those with demanding launch environments.

Internet-Based Digital Simulation for Cleft Surgery Education: A 5-Year Assessment of Demographics, Usage, and Global Effect.

PubMed

Kantar, Rami S; Plana, Natalie M; Cutting, Court B; Diaz-Siso, Jesus Rodrigo; Flores, Roberto L

2018-01-29

In October 2012, a freely available, internet-based cleft simulator was created in partnership between academic, nonprofit, and industry sectors. The purpose of this educational resource was to address global disparities in cleft surgery education. This report assesses demographics, usage, and global effect of our simulator, in its fifth year since inception. Evaluate the global effect, usage, and demographics of an internet-based educational digital simulation cleft surgery software. Simulator modules, available in five languages demonstrate surgical anatomy, markings, detailed procedures, and intraoperative footage to supplement digital animation. Available data regarding number of users, sessions, countries reached, and content access were recorded. Surveys evaluating the demographic characteristics of registered users and simulator use were collected by direct e-mail. The total number of simulator new and active users reached 2865 and 4086 in June 2017, respectively. By June 2017, users from 136 countries had accessed the simulator. From 2015 to 2017, the number of sessions was 11,176 with a monthly average of 399.0 ± 190.0. Developing countries accounted for 35% of sessions and the average session duration was 9.0 ± 7.3 minutes. This yields a total simulator screen time of 100,584 minutes (1676 hours). Most survey respondents were surgeons or trainees (87%) specializing in plastic, maxillofacial, or general surgery (89%). Most users found the simulator to be useful (88%), at least equivalent or more useful than other resources (83%), and used it for teaching (58%). Our internet-based interactive cleft surgery platform reaches its intended target audience, is not restricted by socioeconomic barriers to access, and is judged to be useful by surgeons. More than 4000 active users have been reached since inception. The total screen time over approximately 2 years exceeded 1600 hours. This suggests that future surgical simulators of this kind may be sustainable by

Wind-Stress Simulations and Equatorial Dynamics in an AGCM. Part 1; Basic Results from a 1979-1999 Forced SST Experiment

NASA Technical Reports Server (NTRS)

Bacmeister, Julio T.; Suarez, Max J.; Einaudi, Franco (Technical Monitor)

2001-01-01

This is the first of a two part study examining the connection of the equatorial momentum budget in an AGCM (Atmospheric General Circulation Model), with simulated equatorial surface wind stresses over the Pacific. The AGCM used in this study forms part of a newly developed coupled forecasting system used at NASA's Seasonal- to-Interannual Prediction Project. Here we describe the model and present results from a 20-year (1979-1999) AMIP-type experiment forced with observed SSTs (Sea Surface Temperatures). Model results are compared them with available observational data sets. The climatological pattern of extra-tropical planetary waves as well as their ENSO-related variability is found to agree quite well with re-analysis estimates. The model's surface wind stress is examined in detail, and reveals a reasonable overall simulation of seasonal interannual variability, as well as seasonal mean distributions. However, an excessive annual oscillation in wind stress over the equatorial central Pacific is found. We examine the model's divergent circulation over the tropical Pacific and compare it with estimates based on re-analysis data. These comparisons are generally good, but reveal excessive upper-level convergence in the central Pacific. In Part II of this study a direct examination of individual terms in the AGCM's momentum budget is presented. We relate the results of this analysis to the model's simulation of surface wind stress.

Integrated corridor management analysis, modeling, and simulation results for the test corridor.

DOT National Transportation Integrated Search

2008-06-01

This report documents the Integrated Corridor Management (ICM) Analysis Modeling and Simulation (AMS) tools and strategies used on a Test Corridor, presents results and lessons-learned, and documents the relative capability of AMS to support benefit-...

Dark Energy Survey Year 1 Results: galaxy mock catalogues for BAO

DOE Office of Scientific and Technical Information (OSTI.GOV)

Avila, S.; et al.

Mock catalogues are a crucial tool in the analysis of galaxy surveys data, both for the accurate computation of covariance matrices, and for the optimisation of analysis methodology and validation of data sets. In this paper, we present a set of 1800 galaxy mock catalogues designed to match the Dark Energy Survey Year-1 BAO sample (Crocce et al. 2017) in abundance, observational volume, redshift distribution and uncertainty, and redshift dependent clustering. The simulated samples were built upon HALOGEN (Avila et al. 2015) halo catalogues, based on a $2LPT$ density field with an exponential bias. For each of them, a lightconemore » is constructed by the superposition of snapshots in the redshift range $0.45« less

High-resolution Monte Carlo simulation of flow and conservative transport in heterogeneous porous media: 2. Transport results

USGS Publications Warehouse

Naff, R.L.; Haley, D.F.; Sudicky, E.A.

1998-01-01

In this, the second of two papers concerned with the use of numerical simulation to examine flow and transport parameters in heterogeneous porous media via Monte Carlo methods, results from the transport aspect of these simulations are reported on. Transport simulations contained herein assume a finite pulse input of conservative tracer, and the numerical technique endeavors to realistically simulate tracer spreading as the cloud moves through a heterogeneous medium. Medium heterogeneity is limited to the hydraulic conductivity field, and generation of this field assumes that the hydraulic-conductivity process is second-order stationary. Methods of estimating cloud moments, and the interpretation of these moments, are discussed. Techniques for estimation of large-time macrodispersivities from cloud second-moment data, and for the approximation of the standard errors associated with these macrodispersivities, are also presented. These moment and macrodispersivity estimation techniques were applied to tracer clouds resulting from transport scenarios generated by specific Monte Carlo simulations. Where feasible, moments and macrodispersivities resulting from the Monte Carlo simulations are compared with first- and second-order perturbation analyses. Some limited results concerning the possible ergodic nature of these simulations, and the presence of non-Gaussian behavior of the mean cloud, are reported on as well.

Spin-up simulation behaviors in a climate model to build a basement of long-time simulation

NASA Astrophysics Data System (ADS)

Lee, J.; Xue, Y.; De Sales, F.

2015-12-01

It is essential to develop start-up information when conducting long-time climate simulation. In case that the initial condition is already available from the previous simulation of same type model this does not necessary; however, if not, model needs spin-up simulation to have adjusted and balanced initial condition with the model climatology. Otherwise, a severe spin may take several years. Some of model variables such as deep soil temperature fields and temperature in ocean deep layers in initial fields would affect model's further long-time simulation due to their long residual memories. To investigate the important factor for spin-up simulation in producing an atmospheric initial condition, we had conducted two different spin-up simulations when no atmospheric condition is available from exist datasets. One simulation employed atmospheric global circulation model (AGCM), namely Global Forecast System (GFS) of National Center for Environmental Prediction (NCEP), while the other employed atmosphere-ocean coupled global circulation model (CGCM), namely Climate Forecast System (CFS) of NCEP. Both models share the atmospheric modeling part and only difference is in applying of ocean model coupling, which is conducted by Modular Ocean Model version 4 (MOM4) of Geophysical Fluid Dynamics Laboratory (GFDL) in CFS. During a decade of spin-up simulation, prescribed sea-surface temperature (SST) fields of target year is forced to the GFS daily basis, while CFS digested only first time step ocean condition and freely iterated for the rest of the period. Both models were forced by CO2 condition and solar constant given from the target year. Our analyses of spin-up simulation results indicate that freely conducted interaction between the ocean and the atmosphere is more helpful to produce the initial condition for the target year rather than produced by fixed SST forcing. Since the GFS used prescribed forcing exactly given from the target year, this result is unexpected

Results of Small-scale Solid Rocket Combustion Simulator testing at Marshall Space Flight Center

NASA Technical Reports Server (NTRS)

Goldberg, Benjamin E.; Cook, Jerry

1993-01-01

The Small-scale Solid Rocket Combustion Simulator (SSRCS) program was established at the Marshall Space Flight Center (MSFC), and used a government/industry team consisting of Hercules Aerospace Corporation, Aerotherm Corporation, United Technology Chemical Systems Division, Thiokol Corporation and MSFC personnel to study the feasibility of simulating the combustion species, temperatures and flow fields of a conventional solid rocket motor (SRM) with a versatile simulator system. The SSRCS design is based on hybrid rocket motor principles. The simulator uses a solid fuel and a gaseous oxidizer. Verification of the feasibility of a SSRCS system as a test bed was completed using flow field and system analyses, as well as empirical test data. A total of 27 hot firings of a subscale SSRCS motor were conducted at MSFC. Testing of the Small-scale SSRCS program was completed in October 1992. This paper, a compilation of reports from the above team members and additional analysis of the instrumentation results, will discuss the final results of the analyses and test programs.

Contextualizing the relevance of basic sciences: small-group simulation with debrief for first- and second-year medical students in an integrated curriculum.

PubMed

Ginzburg, Samara B; Brenner, Judith; Cassara, Michael; Kwiatkowski, Thomas; Willey, Joanne M

2017-01-01

There has been a call for increased integration of basic and clinical sciences during preclinical years of undergraduate medical education. Despite the recognition that clinical simulation is an effective pedagogical tool, little has been reported on its use to demonstrate the relevance of basic science principles to the practice of clinical medicine. We hypothesized that simulation with an integrated science and clinical debrief used with early learners would illustrate the importance of basic science principles in clinical diagnosis and management of patients. Small groups of first- and second-year medical students were engaged in a high-fidelity simulation followed by a comprehensive debrief facilitated by a basic scientist and clinician. Surveys including anchored and open-ended questions were distributed at the conclusion of each experience. The majority of the students agreed that simulation followed by an integrated debrief illustrated the clinical relevance of basic sciences (mean ± standard deviation: 93.8% ± 2.9% of first-year medical students; 96.7% ± 3.5% of second-year medical students) and its importance in patient care (92.8% of first-year medical students; 90.4% of second-year medical students). In a thematic analysis of open-ended responses, students felt that these experiences provided opportunities for direct application of scientific knowledge to diagnosis and treatment, improving student knowledge, simulating real-world experience, and developing clinical reasoning, all of which specifically helped them understand the clinical relevance of basic sciences. Small-group simulation followed by a debrief that integrates basic and clinical sciences is an effective means of demonstrating the relationship between scientific fundamentals and patient care for early learners. As more medical schools embrace integrated curricula and seek opportunities for integration, our model is a novel approach that can be utilized.

Reading Recovery Program Implementation Year Six, School Year 1995-96. Report of Results and Effectiveness.

ERIC Educational Resources Information Center

Schotanus, Helen; And Others

A study examined the results and effectiveness of the sixth year of the Reading Recovery program in New Hampshire. With the 95 Reading Recovery teachers from previous classes, 38 teachers in the new class, and 4 teacher leaders, a total of 137 teachers taught Reading Recovery during the 1995-96 school year. A total of 693 first-grade children…

Reading Recovery Program Implementation Year Five, School Year 1994-95. Report of Results and Effectiveness.

ERIC Educational Resources Information Center

Schotanus, Helen; And Others

A study examined the results and effectiveness of the fifth year of the Reading Recovery program in New Hampshire. With the 78 Reading Recovery teachers from previous classes, 23 teachers in the new class, and 3 teacher leaders, a total of 104 teachers taught Reading Recovery during the 1994-95 school year. A total of 530 first-grade children…

Can nutritional information modify purchase of ultra-processed products? Results from a simulated online shopping experiment.

PubMed

Machín, Leandro; Arrúa, Alejandra; Giménez, Ana; Curutchet, María Rosa; Martínez, Joseline; Ares, Gastón

2018-01-01

The aim of the present work was to evaluate the influence of two front-of-pack nutrition information schemes (traffic-light system and Chilean warning system) on consumer purchase of ultra-processed foods in a simulated online grocery store. Following a between-subjects design, participants completed a simulated weekly food purchase in an online grocery store under one of three experimental conditions: (i) a control condition with no nutrition information, (ii) a traffic-light system and (iii) the Chilean warning system. Information about energy (calories), sugar, saturated fats and salt content was included in the nutrition information schemes. Participants were recruited from a consumer database and a Facebook advertisement. People from Montevideo (Uruguay), aged 18-77 years (n 437; 75 % female), participated in the study. All participants were in charge of food purchase in the household, at least occasionally. No significant differences between experimental conditions were found in the mean share of ultra-processed foods purchased by participants, both in terms of number of products and expenditure, or in the mean energy, sugar, saturated fat and salt content of the purchased items. However, the Chilean warning system decreased intended purchase of sweets and desserts. Results from this online simulation provided little evidence to suggest that the traffic-light system or the Chilean warning system in isolation could be effective in reducing purchase of ultra-processed foods or improving the nutritional composition of the purchased products.

Analysis Of Direct Numerical Simulation Results Of Adverse Pressure Gradient Boundary Layer Through Anisotropy Invariant Mapping And Comparison With The Rans Simulations

NASA Astrophysics Data System (ADS)

Gungor, Ayse Gul; Nural, Ozan Ekin; Ertunc, Ozgur

2017-11-01

Purpose of this study is to analyze the direct numerical simulation data of a turbulent boundary layer subjected to strong adverse pressure gradient through anisotropy invariant mapping. RANS simulation using the ``Elliptic Blending Model'' of Manceau and Hanjolic (2002) is also conducted for the same flow case with commercial software Star-CCM+ and comparison of the results with DNS data is done. RANS simulation captures the general trends in the velocity field but, significant deviations are found when skin friction coefficients are compared. Anisotropy invariant map of Lumley and Newman (1977) and barycentric map of Banerjee et al. (2007) are used for the analysis. Invariant mapping of the DNS data has yielded that at locations away from the wall, flow is close to one component turbulence state. In the vicinity of the wall, turbulence is at two component limit which is one border of the barycentric map and as the flow evolves along the streamwise direction, it approaches to two component turbulence state. Additionally, at the locations away from the wall, turbulence approaches to two component limit. Furthermore, analysis of the invariants of the RANS simulations shows dissimilar results. In RANS simulations invariants do not approach to any of the limit states unlike the DNS.

Behaviour of oceanic 137Cs following the Fukushima Daiichi Nuclear Power Plant accident for four years simulated numerically by a regional ocean model

NASA Astrophysics Data System (ADS)

Tsumune, D.; Tsubono, T.; Aoyama, M.; Misumi, K.; Tateda, Y.

2015-12-01

A series of accidents at the Fukushima Dai-ichi Nuclear Power Plant (1F NPP) following the earthquake and tsunami of 11 March 2011 resulted in the release of radioactive materials to the ocean by two major pathways, direct release from the accident site and atmospheric deposition.We reconstructed spatiotemporal variability of 137Cs activity in the regional ocean for four years by numerical model, such as a regional scale and the North Pacific scale oceanic dispersion models, an atmospheric transport model, a sediment transport model, a dynamic biological compartment model for marine biota and river runoff model. Direct release rate of 137Cs were estimated for four years after the accident by comparing simulated results and observed activities very close to the site. The estimated total amounts of directly release was 3.6±0.7 PBq. Directly release rate of 137Cs decreased exponentially with time by the end of December 2012 and then, was almost constant. Decrease rate were quite small after 2013. The daily release rate of 137Cs was estimated to be the order of magnitude of 1010 Bq/day by the end of March 2015. The activity of directly released 137Cs was detectable only in the coastal zone after December 2012. Simulated 137Cs activities attributable to direct release were in good agreement with observed activities, a result that implies the estimated direct release rate was reasonable. There is no observed data of 137Cs activity in the ocean from 11 to 21 March 2011. Observed data of marine biota should reflect the history of 137Cs activity in this early period. We reconstructed the history of 137Cs activity in this early period by considering atmospheric deposition, river input, rain water runoff from the 1F NPP site. The comparisons between simulated 137Cs activity of marine biota by a dynamic biological compartment and observed data also suggest that simulated 137Cs activity attributable to atmospheric deposition was underestimated in this early period. The

Behaviour of oceanic 137Cs following the Fukushima Daiichi Nuclear Power Plant accident for four years simulated numerically by a regional ocean model

NASA Astrophysics Data System (ADS)

Torn, M. S.; Koven, C. D.; Riley, W. J.; Zhu, B.; Hicks Pries, C.; Phillips, C. L.

2014-12-01

A series of accidents at the Fukushima Dai-ichi Nuclear Power Plant (1F NPP) following the earthquake and tsunami of 11 March 2011 resulted in the release of radioactive materials to the ocean by two major pathways, direct release from the accident site and atmospheric deposition.We reconstructed spatiotemporal variability of 137Cs activity in the regional ocean for four years by numerical model, such as a regional scale and the North Pacific scale oceanic dispersion models, an atmospheric transport model, a sediment transport model, a dynamic biological compartment model for marine biota and river runoff model. Direct release rate of 137Cs were estimated for four years after the accident by comparing simulated results and observed activities very close to the site. The estimated total amounts of directly release was 3.6±0.7 PBq. Directly release rate of 137Cs decreased exponentially with time by the end of December 2012 and then, was almost constant. Decrease rate were quite small after 2013. The daily release rate of 137Cs was estimated to be the order of magnitude of 1010 Bq/day by the end of March 2015. The activity of directly released 137Cs was detectable only in the coastal zone after December 2012. Simulated 137Cs activities attributable to direct release were in good agreement with observed activities, a result that implies the estimated direct release rate was reasonable. There is no observed data of 137Cs activity in the ocean from 11 to 21 March 2011. Observed data of marine biota should reflect the history of 137Cs activity in this early period. We reconstructed the history of 137Cs activity in this early period by considering atmospheric deposition, river input, rain water runoff from the 1F NPP site. The comparisons between simulated 137Cs activity of marine biota by a dynamic biological compartment and observed data also suggest that simulated 137Cs activity attributable to atmospheric deposition was underestimated in this early period. The

Multi-Fidelity Simulation of a Turbofan Engine With Results Zoomed Into Mini-Maps for a Zero-D Cycle Simulation

NASA Technical Reports Server (NTRS)

Turner, Mark G.; Reed, John A.; Ryder, Robert; Veres, Joseph P.

2004-01-01

A Zero-D cycle simulation of the GE90-94B high bypass turbofan engine has been achieved utilizing mini-maps generated from a high-fidelity simulation. The simulation utilizes the Numerical Propulsion System Simulation (NPSS) thermodynamic cycle modeling system coupled to a high-fidelity full-engine model represented by a set of coupled 3D computational fluid dynamic (CFD) component models. Boundary conditions from the balanced, steady state cycle model are used to define component boundary conditions in the full-engine model. Operating characteristics of the 3D component models are integrated into the cycle model via partial performance maps generated from the CFD flow solutions using one-dimensional mean line turbomachinery programs. This paper highlights the generation of the high-pressure compressor, booster, and fan partial performance maps, as well as turbine maps for the high pressure and low pressure turbine. These are actually "mini-maps" in the sense that they are developed only for a narrow operating range of the component. Results are compared between actual cycle data at a take-off condition and the comparable condition utilizing these mini-maps. The mini-maps are also presented with comparison to actual component data where possible.

Long-Term Results of Laparoscopic Sleeve Gastrectomy for Morbid Obesity: 5 to 8-Year Results.

PubMed

Gadiot, Ralph P M; Biter, L Ulas; van Mil, Stefanie; Zengerink, Hans F; Apers, J; Mannaerts, Guido H H

2017-01-01

Although long-term results of sleeve gastrectomy (LSG) remain scarce in the literature, its popularity as a stand-alone procedure has accounted for a global increase in LSG performance. In this retrospective study, the authors present 5 to 8-year follow-up results in terms of weight loss, failure/revision rate, and comorbidity resolution from a single center. A prospectively maintained database was reviewed for patients who underwent LSG between 2007 and 2010. Data analysis on weight loss, comorbid conditions, revision surgery, and mortality was conducted. Median percentage excess BMI loss (%EBMIL) was 59.0, and 53.9 %, and median percentage total weight loss (%TWL) was 25.1, and 22.9 % at 5 and 8 years, respectively. Revision to gastric bypass due to insufficient weight loss or gastroesophageal reflux disease (GERD) was performed in 42 patients (15.2 %). Resolution of comorbid condition was achieved in 91 % of patients with obstructive sleep apnea syndrome (OSAS), 68 % of patients with type 2 diabetes (T2DM), 53 % of patients with hypertension, and 25 % of patients with dyslipedemia. Loss to follow-up rate was 45 % at 5 years, 28 % at 6 years, 23 % at 7 years, and 13 % at 8 years. This study adds to the currently available data confirming the LSG to be a safe and effective procedure at long term. Data from high-volume studies are needed to establish the definite role of the LSG in the spectrum of bariatric procedures.

Clinical results of laparoscopic fundoplication at ten years after surgery.

PubMed

Dallemagne, B; Weerts, J; Markiewicz, S; Dewandre, J-M; Wahlen, C; Monami, B; Jehaes, C

2006-01-01

Several studies have demonstrated laparoscopic antireflux surgery (LAS) for the treatment of gastroesophageal reflux disease (GERD) to be efficient at short- and midterm follow-up evaluations. The aim of this study was to evaluate the results for LAS 10 years after surgery. The 100 consecutive patients who underwent LAS by a single surgeon in 1993 were entered into a prospective database. Nissen fundoplication was performed for 68 patients, and partial posterior fundoplication (modified Toupet procedure) was performed for 32 patients. Evaluations of the outcome were made 5 and 10 years after surgery. A structured symptom questionnaire and upper gastrointestinal barium series were used at 5 years. The same questionnaire and an added quality-of-life questionnaire (the Gastrointestinal Quality of Life Index [GIQLI]) were used at 10 years. Seven patients died of unrelated causes during the 10-year period. Four patients underwent revision surgery: one patient for persistent dysphagia and three patients for recurrent reflux symptoms. Three patients were lost to any follow-up study. At 5 years, 93% of the patients were free of significant reflux symptoms. At 10 years, 89.5% of the patients still were free of significant reflux (93.3% after Nissen, 81.8% after Toupet). Major side effects (flatulence and abdominal distension) were related to "wind" problems. The GIQLI scores at 10 years were significantly better than the preoperative scores of the patients under medical therapy with proton pump inhibitors. Elimination of GERD symptoms improved quality of life and eliminated the need for daily acid suppression in most patients. These results, apparent 5 years after the operation, still were valid at 10 years.

Dark Energy Survey Year 1 Results: Weak Lensing Shape Catalogues

DOE Office of Scientific and Technical Information (OSTI.GOV)

Zuntz, J.; et al.

We present two galaxy shape catalogues from the Dark Energy Survey Year 1 data set, covering 1500 square degrees with a median redshift ofmore » $0.59$. The catalogues cover two main fields: Stripe 82, and an area overlapping the South Pole Telescope survey region. We describe our data analysis process and in particular our shape measurement using two independent shear measurement pipelines, METACALIBRATION and IM3SHAPE. The METACALIBRATION catalogue uses a Gaussian model with an innovative internal calibration scheme, and was applied to $riz$-bands, yielding 34.8M objects. The IM3SHAPE catalogue uses a maximum-likelihood bulge/disc model calibrated using simulations, and was applied to $r$-band data, yielding 21.9M objects. Both catalogues pass a suite of null tests that demonstrate their fitness for use in weak lensing science. We estimate the 1$$\\sigma$$ uncertainties in multiplicative shear calibration to be $0.013$ and $0.025$ for the METACALIBRATION and IM3SHAPE catalogues, respectively.« less

From Simulation to Real Robots with Predictable Results: Methods and Examples

NASA Astrophysics Data System (ADS)

Balakirsky, S.; Carpin, S.; Dimitoglou, G.; Balaguer, B.

From a theoretical perspective, one may easily argue (as we will in this chapter) that simulation accelerates the algorithm development cycle. However, in practice many in the robotics development community share the sentiment that “Simulation is doomed to succeed” (Brooks, R., Matarić, M., Robot Learning, Kluwer Academic Press, Hingham, MA, 1993, p. 209). This comes in large part from the fact that many simulation systems are brittle; they do a fair-to-good job of simulating the expected, and fail to simulate the unexpected. It is the authors' belief that a simulation system is only as good as its models, and that deficiencies in these models lead to the majority of these failures. This chapter will attempt to address these deficiencies by presenting a systematic methodology with examples for the development of both simulated mobility models and sensor models for use with one of today's leading simulation engines. Techniques for using simulation for algorithm development leading to real-robot implementation will be presented, as well as opportunities for involvement in international robotics competitions based on these techniques.

Why Isn't There More High-fidelity Simulation Training in Diagnostic Radiology? Results of a Survey of Academic Radiologists.

PubMed

Cook, Tessa S; Hernandez, Jessica; Scanlon, Mary; Langlotz, Curtis; Li, Chun-Der L

2016-07-01

Despite its increasing use in training other medical specialties, high-fidelity simulation to prepare diagnostic radiology residents for call remains an underused educational resource. To attempt to characterize the barriers toward adoption of this technology, we conducted a survey of academic radiologists and radiology trainees. An Institutional Review Board-approved survey was distributed to the Association of University Radiologists members via e-mail. Survey results were collected electronically, tabulated, and analyzed. A total of 68 survey responses representing 51 programs were received from program directors, department chairs, chief residents, and program administrators. The most common form of educational activity for resident call preparation was lectures. Faculty supervised "baby call" was also widely reported. Actual simulated call environments were quite rare with only three programs reporting this type of educational activity. Barriers to the use of simulation include lack of faculty time, lack of faculty expertise, and lack of perceived need. High-fidelity simulation can be used to mimic the high-stress, high-stakes independent call environment that the typical radiology resident encounters during the second year of training, and can provide objective data for program directors to assess the Accreditation Council of Graduate Medical Education milestones. We predict that this technology will begin to supplement traditional diagnostic radiology teaching methods and to improve patient care and safety in the next decade. Published by Elsevier Inc.

Clinical results of computerized tomography-based simulation with laser patient marking.

PubMed

Ragan, D P; Forman, J D; He, T; Mesina, C F

1996-02-01

Accuracy of a patient treatment portal marking device and computerized tomography (CT) simulation have been clinically tested. A CT-based simulator has been assembled based on a commercial CT scanner. This includes visualization software and a computer-controlled laser drawing device. This laser drawing device is used to transfer the setup, central axis, and/or radiation portals from the CT simulator to the patient for appropriate patient skin marking. A protocol for clinical testing is reported. Twenty-five prospectively, sequentially accessioned patients have been analyzed. The simulation process can be completed in an average time of 62 min. Under many cases, the treatment portals can be designed and the patient marked in one session. Mechanical accuracy of the system was found to be within +/- 1mm. The portal projection accuracy in clinical cases is observed to be better than +/- 1.2 mm. Operating costs are equivalent to the conventional simulation process it replaces. Computed tomography simulation is a clinical accurate substitute for conventional simulation when used with an appropriate patient marking system and digitally reconstructed radiographs. Personnel time spent in CT simulation is equivalent to time in conventional simulation.

Mercury's plasma belt: hybrid simulations results compared to in-situ measurements

NASA Astrophysics Data System (ADS)

Hercik, D.; Travnicek, P. M.; Schriver, D.; Hellinger, P.

2012-12-01

The presence of plasma belt and trapped particles region in the Mercury's inner magnetosphere has been questionable due to small dimensions of the magnetosphere of Mercury compared to Earth, where these regions are formed. Numerical simulations of the solar wind interaction with Mercury's magnetic field suggested that such a structure could be found also in the vicinity of Mercury. These results has been recently confirmed also by MESSENGER observations. Here we present more detailed analysis of the plasma belt structure and quasi-trapped particle population characteristics and behaviour under different orientations of the interplanetary magnetic field.The plasma belt region is constantly supplied with solar wind protons via magnetospheric flanks and tail current sheet region. Protons inside the plasma belt region are quasi-trapped in the magnetic field of Mercury and perform westward drift along the planet. This region is well separated by a magnetic shell and has higher average temperatures and lower bulk proton current densities than surrounding area. On the day side the population exhibits loss cone distribution function matching the theoretical loss cone angle. Simulations results are also compared to in-situ measurements acquired by MESSENGER MAG and FIPS instruments.

Result of Monte-Carlo simulation of electron-photon cascades in lead and layers of lead-scintillator

NASA Technical Reports Server (NTRS)

Wasilewski, A.; Krys, E.

1985-01-01

Results of Monte-Carlo simulation of electromagnetic cascade development in lead and lead-scintillator sandwiches are analyzed. It is demonstrated that the structure function for core approximation is not applicable in the case in which the primary energy is higher than 100 GeV. The simulation data has shown that introducing an inhomogeneous chamber structure results in subsequent reduction of secondary particles.

Prediction of SFL Interruption Performance from the Results of Arc Simulation during High-Current Phase

NASA Astrophysics Data System (ADS)

Lee, Jong-Chul; Lee, Won-Ho; Kim, Woun-Jea

2015-09-01

The design and development procedures of SF6 gas circuit breakers are still largely based on trial and error through testing although the development costs go higher every year. The computation cannot cover the testing satisfactorily because all the real processes arc not taken into account. But the knowledge of the arc behavior and the prediction of the thermal-flow inside the interrupters by numerical simulations are more useful than those by experiments due to the difficulties to obtain physical quantities experimentally and the reduction of computational costs in recent years. In this paper, in order to get further information into the interruption process of a SF6 self-blast interrupter, which is based on a combination of thermal expansion and the arc rotation principle, gas flow simulations with a CFD-arc modeling are performed during the whole switching process such as high-current period, pre-current zero period, and current-zero period. Through the complete work, the pressure-rise and the ramp of the pressure inside the chamber before current zero as well as the post-arc current after current zero should be a good criterion to predict the short-line fault interruption performance of interrupters.

Ground Source Heat Pump Computational Results

DOE Data Explorer

James Menart

2013-07-31

This data submission includes simulation results for ground loop heat pump systems located in 6 different cities across the United States. The cities are Boston, MA, Dayton, OH, Omaha, NE, Orlando, FL, Sacramento, CA, and St. Paul, MN. These results were obtained from the two-dimensional geothermal computer code called GEO2D. GEO2D was written as part of this DOE funded grant. The results included in this submission for each of the 6 cities listed above are: 1) specific information on the building being heated or cooled by the ground loop geothermal system, 2) some extreme values for the building heating and cooling loads during the year, 3) the inputs required to carry out the simulation, 4) a plot of the hourly building heating and cooling loads throughout the year, 5) a plot of the fluid temperature exiting the ground loop for a 20 year period, 6) a plot of the heat exchange between the ground loop and the ground for a 20 year period, and 7) ground and ground loop temperature contour plots at different times of the year for the 20 year period.

Simulating the effects of the southern pine beetle on regional dynamics 60 years into the future

Treesearch

Jennifer K. Costanza; Jiri Hulcr; Frank H. Koch; Todd Earnhardt; Alexa J. McKerrow; Rob R. Dunn; Jaime A. Collazo

2012-01-01

We developed a spatially explicit model that simulated future southern pine beetle (Dendroctonus frontalis, SPB) dynamics and pine forest management for a real landscape over 60 years to inform regional forest management. The SPB has a considerable effect on forest dynamics in the Southeastern United States, especially in loblolly pine (...

Introducing Third-Year Undergraduates to GEANT4 Simulations of Light Transport and Collection in Scintillation Materials

ERIC Educational Resources Information Center

Riggi, Simone; La Rocca, Paola; Riggi, Francesco

2011-01-01

GEANT4 simulations of the processes affecting the transport and collection of optical photons generated inside a scintillation detector were carried out, with the aim to complement the educational material offered by textbooks to third-year physics undergraduates. Two typical situations were considered: a long scintillator strip with and without a…

Transient climate simulations of the deglaciation 21-9 thousand years before present; PMIP4 Core experiment design and boundary conditions

NASA Astrophysics Data System (ADS)

Ivanovic, Ruza; Gregoire, Lauren; Kageyama, Masa; Roche, Didier; Valdes, Paul; Burke, Andrea; Drummond, Rosemarie; Peltier, W. Richard; Tarasov, Lev

2016-04-01

The last deglaciation, which marked the transition between the last glacial and present interglacial periods, was punctuated by a series of rapid (centennial and decadal) climate changes. Numerical climate models are useful for investigating mechanisms that underpin the events, especially now that some of the complex models can be run for multiple millennia. We have set up a Paleoclimate Modelling Intercomparison Project (PMIP) working group to coordinate efforts to run transient simulations of the last deglaciation, and to facilitate the dissemination of expertise between modellers and those engaged with reconstructing the climate of the last 21 thousand years. Here, we present the design of a coordinated Core simulation over the period 21-9 thousand years before present (ka) with time varying orbital forcing, greenhouse gases, ice sheets, and other geographical changes. A choice of two ice sheet reconstructions is given. Additional focussed simulations will also be coordinated on an ad-hoc basis by the working group, for example to investigate the effect of ice sheet and iceberg meltwater, and the uncertainty in other forcings. Some of these focussed simulations will concentrate on shorter durations around specific events to allow the more computationally expensive models to take part. Ivanovic, R. F., Gregoire, L. J., Kageyama, M., Roche, D. M., Valdes, P. J., Burke, A., Drummond, R., Peltier, W. R., and Tarasov, L.: Transient climate simulations of the deglaciation 21-9 thousand years before present; PMIP4 Core experiment design and boundary conditions, Geosci. Model Dev. Discuss., 8, 9045-9102, doi:10.5194/gmdd-8-9045-2015, 2015.

A simulation study of Large Area Crop Inventory Experiment (LACIE) technology

NASA Technical Reports Server (NTRS)

Ziegler, L. (Principal Investigator); Potter, J.

1979-01-01

The author has identified the following significant results. The LACIE performance predictor (LPP) was used to replicate LACIE phase 2 for a 15 year period, using accuracy assessment results for phase 2 error components. Results indicated that the (LPP) simulated the LACIE phase 2 procedures reasonably well. For the 15 year simulation, only 7 of the 15 production estimates were within 10 percent of the true production. The simulations indicated that the acreage estimator, based on CAMS phase 2 procedures, has a negative bias. This bias was too large to support the 90/90 criterion with the CV observed and simulated for the phase 2 production estimator. Results of this simulation study validate the theory that the acreage variance estimator in LACIE was conservative.

Nanofiltration Results: Membrane Removal of Calcium, Magnesium, Sodium, Silica, Lithium, Chlorine, and Sulfate from Simulated Geothermal Brines

DOE Data Explorer

Jay Renew

2016-02-06

Results from a nanofiltration study utilizing simulated geothermal brines. The data includes a PDF documenting the process used to remove Calcium, Magnesium, Sodium, Silica, Lithium, Chlorine, and Sulfate from simulated geothermal brines. Three different membranes were evaluated. The results were analyzed using inductively coupled plasma mass spectrometry (ICP-MS).

Challenges in validating model results for first year ice

NASA Astrophysics Data System (ADS)

Melsom, Arne; Eastwood, Steinar; Xie, Jiping; Aaboe, Signe; Bertino, Laurent

2017-04-01

In order to assess the quality of model results for the distribution of first year ice, a comparison with a product based on observations from satellite-borne instruments has been performed. Such a comparison is not straightforward due to the contrasting algorithms that are used in the model product and the remote sensing product. The implementation of the validation is discussed in light of the differences between this set of products, and validation results are presented. The model product is the daily updated 10-day forecast from the Arctic Monitoring and Forecasting Centre in CMEMS. The forecasts are produced with the assimilative ocean prediction system TOPAZ. Presently, observations of sea ice concentration and sea ice drift are introduced in the assimilation step, but data for sea ice thickness and ice age (or roughness) are not included. The model computes the age of the ice by recording and updating the time passed after ice formation as sea ice grows and deteriorates as it is advected inside the model domain. Ice that is younger than 365 days is classified as first year ice. The fraction of first-year ice is recorded as a tracer in each grid cell. The Ocean and Sea Ice Thematic Assembly Centre in CMEMS redistributes a daily product from the EUMETSAT OSI SAF of gridded sea ice conditions which include "ice type", a representation of the separation of regions between those infested by first year ice, and those infested by multi-year ice. The ice type is parameterized based on data for the gradient ratio GR(19,37) from SSMIS observations, and from the ASCAT backscatter parameter. This product also includes information on ambiguity in the processing of the remote sensing data, and the product's confidence level, which have a strong seasonal dependency.

Ion velocity distribution functions in argon and helium discharges: detailed comparison of numerical simulation results and experimental data

NASA Astrophysics Data System (ADS)

Wang, Huihui; Sukhomlinov, Vladimir S.; Kaganovich, Igor D.; Mustafaev, Alexander S.

2017-02-01

Using the Monte Carlo collision method, we have performed simulations of ion velocity distribution functions (IVDF) taking into account both elastic collisions and charge exchange collisions of ions with atoms in uniform electric fields for argon and helium background gases. The simulation results are verified by comparison with the experiment data of the ion mobilities and the ion transverse diffusion coefficients in argon and helium. The recently published experimental data for the first seven coefficients of the Legendre polynomial expansion of the ion energy and angular distribution functions are used to validate simulation results for IVDF. Good agreement between measured and simulated IVDFs shows that the developed simulation model can be used for accurate calculations of IVDFs.

Simulated Disaster Day: Benefit From Lessons Learned Through Years of Transformation From Silos to Interprofessional Education.

PubMed

Livingston, Laura L; West, Courtney A; Livingston, Jerry L; Landry, Karen A; Watzak, Bree C; Graham, Lori L

2016-08-01

Disaster Day is a simulation event that began in the College of Nursing and has increased exponentially in size and popularity for the last 8 years. The evolution has been the direct result of reflective practice and dedicated leadership in the form of students, faculty, and administration. Its development and expansion into a robust interprofessional education activity are noteworthy because it gives health care professions students an opportunity to work in teams to provide care in a disaster setting. The "authentic" learning situation has enhanced student knowledge of roles and responsibilities and seems to increase collaborative efforts with other disciplines. The lessons learned and modifications made in our Disaster Day planning, implementation, and evaluation processes are shared in an effort to facilitate best practices for other institutions interested in a similar activity.

A simulation study of spine biofidelity in the hybrid-III 6-year-old ATD.

PubMed

Wu, Jun; Cao, Libo; Reed, Matthew P; Hu, Jingwen

2013-01-01

Because of the lack of pediatric biomechanical data, Hybrid-III (HIII) child anthropomorphic test devices (ATDs) are essentially scaled from the mid-size male ATD based on the geometric considerations. These ATDs inherit a rigid thoracic spine from the adult HIII ATDs, which has been criticized as unrealistic. Therefore, the objective of this study was to explore possible design modifications for improving the spine biofidelity of the HIII 6-year-old ATD. A previously developed and validated HIII 6-year-old MADYMO ATD model was used as the baseline model to investigate the effects of design modifications on the spine biofidelity of the current ATD. Several sets of child volunteer and cadaver test data were considered as the design targets, including child volunteer low-speed crash test data, pediatric cadaver cervical spine tensile test data, and child cadaver crash test data. ATD design modifications include adding an additional joint to the thoracic spine region and changing the joint characteristics at the cervical and lumbar spine regions. Optimization techniques were used to match simulation results to each set of test results. The results indicate that the translational characteristics of the cervical and lumbar spine in the current child ATD need to be reduced to achieve realistic spine flexibility. Adding an additional joint at the thoracic spine region with degree of freedom in both flexion/extension and tension would significantly improve the ATD biofidelity in terms of predicting the overall spine curvature and head excursion in frontal crashes. Future ATD spine modification should focus on reducing the neck and lumbar tension stiffness and adding additional flexibility both in flexion/extension and tension at the thoracic spine region. The child ATD model developed in this study can be used as an important tool to improve child ATD biofidelity and child restraint system design in motor vehicle crashes.

Analysis Results for Lunar Soil Simulant Using a Portable X-Ray Fluorescence Analyzer

NASA Technical Reports Server (NTRS)

Boothe, R. E.

2006-01-01

Lunar soil will potentially be used for oxygen generation, water generation, and as filler for building blocks during habitation missions on the Moon. NASA s in situ fabrication and repair program is evaluating portable technologies that can assess the chemistry of lunar soil and lunar soil simulants. This Technical Memorandum summarizes the results of the JSC 1 lunar soil simulant analysis using the TRACeR III IV handheld x-ray fluorescence analyzer, manufactured by KeyMaster Technologies, Inc. The focus of the evaluation was to determine how well the current instrument configuration would detect and quantify the components of JSC-1.

Fisics-Incor bovine pericardial bioprostheses: 15 year results.

PubMed

Pomerantzeff, P M; Brandao, C M; Cauduro, P; Puig, L B; Grinberg, M; Tarasoutchi, F; Cardoso, L F; Lerner, A; Stolf, N A; Verginelli, G; Jatene, A D

1998-01-01

From March 1982 to December 1995, 2,607 Fisics-Incor bovine pericardial bioprostheses were implanted in 2,259 patients. Mean age was 47.2 +/- 17.5 years, and 55% were male. Rheumatic fever was present in 1,301 (45.7%) patients. One thousand and seventy-three aortic valve replacements, 1,085 mitral replacements, 27 tricuspid replacements, 195 mitral-aortic replacements, and 16 other combined valve replacements were carried out. Combined procedures were performed in 788 (32.9%) patients, the most frequent being tricuspid valve repair (9.2%) and coronary artery bypass grafting (7.7%). Hospital mortality was 8.6% (194 patients), 8.6% for the mitral group, 4.7% for the aortic group, and 12.8% for double-valve replacements. The linear rates for calcification, thromboembolism, rupture, leak and endocarditis were, respectively, 1.1%, 0.2%, 0.9%, 0.1% and 0.5% patient-year. The actuarial survival curve was 56.7 +/- 5.4% in 15 years. Survival free from endocarditis was 91.92%, survival free from thromboembolism was 95 +/- 1.7%, survival free from rupture was 43.7 +/- 9.8%, survival free from leak was 98.9 +/- 4.5%, and survival free from calcification was 48.8 +/- 7.9% in 15 years. In the late postoperative period, 1,614 (80.6%) patients were in New York Heart Association functional Class I. We conclude that the results with the Fisics-Incor bovine pericardial prostheses were satisfactory in our group of patients.

Some results on ethnic conflicts based on evolutionary game simulation

NASA Astrophysics Data System (ADS)

Qin, Jun; Yi, Yunfei; Wu, Hongrun; Liu, Yuhang; Tong, Xiaonian; Zheng, Bojin

2014-07-01

The force of the ethnic separatism, essentially originating from the negative effect of ethnic identity, is damaging the stability and harmony of multiethnic countries. In order to eliminate the foundation of the ethnic separatism and set up a harmonious ethnic relationship, some scholars have proposed a viewpoint: ethnic harmony could be promoted by popularizing civic identity. However, this viewpoint is discussed only from a philosophical prospective and still lacks support of scientific evidences. Because ethnic group and ethnic identity are products of evolution and ethnic identity is the parochialism strategy under the perspective of game theory, this paper proposes an evolutionary game simulation model to study the relationship between civic identity and ethnic conflict based on evolutionary game theory. The simulation results indicate that: (1) the ratio of individuals with civic identity has a negative association with the frequency of ethnic conflicts; (2) ethnic conflict will not die out by killing all ethnic members once for all, and it also cannot be reduced by a forcible pressure, i.e., increasing the ratio of individuals with civic identity; (3) the average frequencies of conflicts can stay in a low level by promoting civic identity periodically and persistently.

Comparison of Observed Spatio-temporal Aftershock Patterns with Earthquake Simulator Results

NASA Astrophysics Data System (ADS)

Kroll, K.; Richards-Dinger, K. B.; Dieterich, J. H.

2013-12-01

Due to the complex nature of faulting in southern California, knowledge of rupture behavior near fault step-overs is of critical importance to properly quantify and mitigate seismic hazards. Estimates of earthquake probability are complicated by the uncertainty that a rupture will stop at or jump a fault step-over, which affects both the magnitude and frequency of occurrence of earthquakes. In recent years, earthquake simulators and dynamic rupture models have begun to address the effects of complex fault geometries on earthquake ground motions and rupture propagation. Early models incorporated vertical faults with highly simplified geometries. Many current studies examine the effects of varied fault geometry, fault step-overs, and fault bends on rupture patterns; however, these works are limited by the small numbers of integrated fault segments and simplified orientations. The previous work of Kroll et al., 2013 on the northern extent of the 2010 El Mayor-Cucapah rupture in the Yuha Desert region uses precise aftershock relocations to show an area of complex conjugate faulting within the step-over region between the Elsinore and Laguna Salada faults. Here, we employ an innovative approach of incorporating this fine-scale fault structure defined through seismological, geologic and geodetic means in the physics-based earthquake simulator, RSQSim, to explore the effects of fine-scale structures on stress transfer and rupture propagation and examine the mechanisms that control aftershock activity and local triggering of other large events. We run simulations with primary fault structures in state of California and northern Baja California and incorporate complex secondary faults in the Yuha Desert region. These models produce aftershock activity that enables comparison between the observed and predicted distribution and allow for examination of the mechanisms that control them. We investigate how the spatial and temporal distribution of aftershocks are affected by

Defining the Simulation Technician Role: Results of a Survey-Based Study.

PubMed

Bailey, Rachel; Taylor, Regina G; FitzGerald, Michael R; Kerrey, Benjamin T; LeMaster, Thomas; Geis, Gary L

2015-10-01

In health care simulation, simulation technicians perform multiple tasks to support various educational offerings. Technician responsibilities and the tasks that accompany them seem to vary between centers. The objectives were to identify the range and frequency of tasks that technicians perform and to determine if there is a correspondence between what technicians do and what they feel their responsibilities should be. We hypothesized that there is a core set of responsibilities and tasks for the technician position regardless of background, experience, and type of simulation center. We conducted a prospective, survey-based study of individuals currently functioning in a simulation technician role in a simulation center. This survey was designed internally and piloted within 3 academic simulation centers. Potential respondents were identified through a national mailing list, and the survey was distributed electronically during a 3-week period. A survey request was sent to 280 potential participants, 136 (49%) responded, and 73 met inclusion criteria. Five core tasks were identified as follows: equipment setup and breakdown, programming scenarios into software, operation of software during simulation, audiovisual support for courses, and on-site simulator maintenance. Independent of background before they were hired, technicians felt unprepared for their role once taking the position. Formal training was identified as a need; however, the majority of technicians felt experience over time was the main contributor toward developing knowledge and skills within their role. This study represents a first step in defining the technician role within simulation-based education and supports the need for the development of a formal job description to allow recruitment, development, and certification.

Multi-ensemble regional simulation of Indian monsoon during contrasting rainfall years: role of convective schemes and nested domain

NASA Astrophysics Data System (ADS)

Devanand, Anjana; Ghosh, Subimal; Paul, Supantha; Karmakar, Subhankar; Niyogi, Dev

2018-06-01

Regional simulations of the seasonal Indian summer monsoon rainfall (ISMR) require an understanding of the model sensitivities to physics and resolution, and its effect on the model uncertainties. It is also important to quantify the added value in the simulated sub-regional precipitation characteristics by a regional climate model (RCM), when compared to coarse resolution rainfall products. This study presents regional model simulations of ISMR at seasonal scale using the Weather Research and Forecasting (WRF) model with the synoptic scale forcing from ERA-interim reanalysis, for three contrasting monsoon seasons, 1994 (excess), 2002 (deficit) and 2010 (normal). Impact of four cumulus schemes, viz., Kain-Fritsch (KF), Betts-Janjić-Miller, Grell 3D and modified Kain-Fritsch (KFm), and two micro physical parameterization schemes, viz., WRF Single Moment Class 5 scheme and Lin et al. scheme (LIN), with eight different possible combinations are analyzed. The impact of spectral nudging on model sensitivity is also studied. In WRF simulations using spectral nudging, improvement in model rainfall appears to be consistent in regions with topographic variability such as Central Northeast and Konkan Western Ghat sub-regions. However the results are also dependent on choice of cumulus scheme used, with KF and KFm providing relatively good performance and the eight member ensemble mean showing better results for these sub-regions. There is no consistent improvement noted in Northeast and Peninsular Indian monsoon regions. Results indicate that the regional simulations using nested domains can provide some improvements on ISMR simulations. Spectral nudging is found to improve upon the model simulations in terms of reducing the intra ensemble spread and hence the uncertainty in the model simulated precipitation. The results provide important insights regarding the need for further improvements in the regional climate simulations of ISMR for various sub-regions and contribute

Multi-ensemble regional simulation of Indian monsoon during contrasting rainfall years: role of convective schemes and nested domain

NASA Astrophysics Data System (ADS)

Devanand, Anjana; Ghosh, Subimal; Paul, Supantha; Karmakar, Subhankar; Niyogi, Dev

2017-08-01

Regional simulations of the seasonal Indian summer monsoon rainfall (ISMR) require an understanding of the model sensitivities to physics and resolution, and its effect on the model uncertainties. It is also important to quantify the added value in the simulated sub-regional precipitation characteristics by a regional climate model (RCM), when compared to coarse resolution rainfall products. This study presents regional model simulations of ISMR at seasonal scale using the Weather Research and Forecasting (WRF) model with the synoptic scale forcing from ERA-interim reanalysis, for three contrasting monsoon seasons, 1994 (excess), 2002 (deficit) and 2010 (normal). Impact of four cumulus schemes, viz., Kain-Fritsch (KF), Betts-Janjić-Miller, Grell 3D and modified Kain-Fritsch (KFm), and two micro physical parameterization schemes, viz., WRF Single Moment Class 5 scheme and Lin et al. scheme (LIN), with eight different possible combinations are analyzed. The impact of spectral nudging on model sensitivity is also studied. In WRF simulations using spectral nudging, improvement in model rainfall appears to be consistent in regions with topographic variability such as Central Northeast and Konkan Western Ghat sub-regions. However the results are also dependent on choice of cumulus scheme used, with KF and KFm providing relatively good performance and the eight member ensemble mean showing better results for these sub-regions. There is no consistent improvement noted in Northeast and Peninsular Indian monsoon regions. Results indicate that the regional simulations using nested domains can provide some improvements on ISMR simulations. Spectral nudging is found to improve upon the model simulations in terms of reducing the intra ensemble spread and hence the uncertainty in the model simulated precipitation. The results provide important insights regarding the need for further improvements in the regional climate simulations of ISMR for various sub-regions and contribute

Assessing regional climate simulations of the last 30 years (1982-2012) over Ganges-Brahmaputra-Meghna River Basin

NASA Astrophysics Data System (ADS)

Khandu; Awange, Joseph L.; Anyah, Richard; Kuhn, Michael; Fukuda, Yoichi

2017-10-01

The Ganges-Brahmaputra-Meghna (GBM) River Basin presents a spatially diverse hydrological regime due to it's complex topography and escalating demand for freshwater resources. This presents a big challenge in applying the current state-of-the-art regional climate models (RCMs) for climate change impact studies in the GBM River Basin. In this study, several RCM simulations generated by RegCM4.4 and PRECIS are assessed for their seasonal and interannual variations, onset/withdrawal of the Indian monsoon, and long-term trends in precipitation and temperature from 1982 to 2012. The results indicate that in general, RegCM4.4 and PRECIS simulations appear to reasonably reproduce the mean seasonal distribution of precipitation and temperature across the GBM River Basin, although the two RCMs are integrated over a different domain size. On average, the RegCM4.4 simulations overestimate monsoon precipitation by {˜ }26 and {˜ }5% in the Ganges and Brahmaputra-Meghna River Basin, respectively, while PRECIS simulations underestimate (overestimate) the same by {˜ }7% ({˜ }16%). Both RegCM4.4 and PRECIS simulations indicate an intense cold bias (up to 10° C) in the Himalayas, and are generally stronger in the RegCM4.4 simulations. Additionally, they tend to produce high precipitation between April and May in the Ganges (RegCM4.4 simulations) and Brahmaputra-Meghna (PRECIS simulations) River Basins, resulting in early onset of the Indian monsoon in the Ganges River Basin. PRECIS simulations exhibit a delayed monsoon withdrawal in the Brahmaputra-Meghna River Basin. Despite large spatial variations in onset and withdrawal periods across the GBM River Basin, the basin-averaged results agree reasonably well with the observed periods. Although global climate model (GCM) driven simulations are generally poor in representing the interannual variability of precipitation and winter temperature variations, they tend to agree well with observed precipitation anomalies when driven by

First results from the IllustrisTNG simulations: the galaxy colour bimodality

NASA Astrophysics Data System (ADS)

Nelson, Dylan; Pillepich, Annalisa; Springel, Volker; Weinberger, Rainer; Hernquist, Lars; Pakmor, Rüdiger; Genel, Shy; Torrey, Paul; Vogelsberger, Mark; Kauffmann, Guinevere; Marinacci, Federico; Naiman, Jill

2018-03-01

We introduce the first two simulations of the IllustrisTNG project, a next generation of cosmological magnetohydrodynamical simulations, focusing on the optical colours of galaxies. We explore TNG100, a rerun of the original Illustris box, and TNG300, which includes 2 × 25003 resolution elements in a volume 20 times larger. Here, we present first results on the galaxy colour bimodality at low redshift. Accounting for the attenuation of stellar light by dust, we compare the simulated (g - r) colours of 109 < M⋆/M⊙ < 1012.5 galaxies to the observed distribution from the Sloan Digital Sky Survey. We find a striking improvement with respect to the original Illustris simulation, as well as excellent quantitative agreement with the observations, with a sharp transition in median colour from blue to red at a characteristic M⋆ ˜ 1010.5 M⊙. Investigating the build-up of the colour-mass plane and the formation of the red sequence, we demonstrate that the primary driver of galaxy colour transition is supermassive black hole feedback in its low accretion state. Across the entire population the median colour transition time-scale Δtgreen is ˜1.6 Gyr, a value which drops for increasingly massive galaxies. We find signatures of the physical process of quenching: at fixed stellar mass, redder galaxies have lower star formation rates, gas fractions, and gas metallicities; their stellar populations are also older and their large-scale interstellar magnetic fields weaker than in bluer galaxies. Finally, we measure the amount of stellar mass growth on the red sequence. Galaxies with M⋆ > 1011 M⊙ which redden at z < 1 accumulate on average ˜25 per cent of their final z = 0 mass post-reddening; at the same time, ˜18 per cent of such massive galaxies acquire half or more of their final stellar mass while on the red sequence.

Results of Simulated Galactic Cosmic Radiation (GCR) and Solar Particle Events (SPE) on Spectra Restraint Fabric

NASA Technical Reports Server (NTRS)

Peters, Benjamin; Hussain, Sarosh; Waller, Jess

2017-01-01

Spectra or similar Ultra-high-molecular-weight polyethylene (UHMWPE) fabric is the likely choice for future structural space suit restraint materials due to its high strength-to-weight ratio, abrasion resistance, and dimensional stability. During long duration space missions, space suits will be subjected to significant amounts of high-energy radiation from several different sources. To insure that pressure garment designs properly account for effects of radiation, it is important to characterize the mechanical changes to structural materials after they have been irradiated. White Sands Test Facility (WSFTF) collaborated with the Crew and Thermal Systems Division at the Johnson Space Center (JSC) to irradiate and test various space suit materials by examining their tensile properties through blunt probe puncture testing and single fiber tensile testing after the materials had been dosed at various levels of simulated GCR and SPE Iron and Proton beams at Brookhaven National Laboratories. The dosages were chosen based on a simulation developed by the Structural Engineering Division at JSC for the expected radiation dosages seen by space suit softgoods seen on a Mars reference mission. Spectra fabric tested in the effort saw equivalent dosages at 2x, 10x, and 20x the predicted dose as well as a simulated 50 year exposure to examine the range of effects on the material and examine whether any degradation due to GCR would be present if the suit softgoods were stored in deep space for a long period of time. This paper presents the results of this work and outlines the impact on space suit pressure garment design for long duration deep space missions.

Ten Years of Simulation in Healthcare: A Thematic Analysis of Editorials.

PubMed

Nestel, Debra

2017-10-01

In this commentary, I review 38 articles published as editorials in Simulation in Healthcare from inception to April 2016. Of the 27 authors, there was a predominance of medical doctors (63%), male authors (67%), and work originating in the United States (86%). The founding Editor-in-Chief Dr David Gaba contributed to half of the editorials. Using inductive thematic analysis, the following five themes were identified: "embedding" simulation, simulation responding to clinical practice, educational considerations for simulation, research practices, and communicating leadership and scholarship about the community. After thematic analysis, the theoretical notion of communities of practice was used to make further meaning of the themes. This theorizing process reveals that editorial content aligns with the features of an evolving community of practice. The editorials seem to have responded to and shaped contemporary simulation practices. The editorial is a powerful forum in which to frame issues relevant to the healthcare simulation community. As the founding Editor-in-Chief, Gaba has made an extraordinary contribution to the Society for Simulation in Healthcare, in these editorials and the broader healthcare simulation community. Under the leadership of the Editor-in-Chief, Dr Mark Scerbo, I am confident that the editorial voice will continue in the true spirit of scholarship.

Personal Access Satellite System (PASS) study. Fiscal year 1989 results

NASA Technical Reports Server (NTRS)

Sue, Miles K. (Editor)

1990-01-01

The Jet Propulsion Laboratory is exploring the potential and feasibility of a personal access satellite system (PASS) that will offer the user greater freedom and mobility than existing or currently planned communications systems. Studies performed in prior years resulted in a strawman design and the identification of technologies that are critical to the successful implementation of PASS. The study efforts in FY-89 were directed towards alternative design options with the objective of either improving the system performance or alleviating the constraints on the user terminal. The various design options and system issues studied this year and the results of the study are presented.

Panchromatic spectral energy distributions of simulated galaxies: results at redshift z = 0

NASA Astrophysics Data System (ADS)

Goz, David; Monaco, Pierluigi; Granato, Gian Luigi; Murante, Giuseppe; Domínguez-Tenreiro, Rosa; Obreja, Aura; Annunziatella, Marianna; Tescari, Edoardo

2017-08-01

We present predictions of spectral energy distributions (SEDs), from the UV to the FIR, of simulated galaxies at z = 0. These were obtained by post-processing the results of an N-body+hydro simulation of a cosmological box of side 25 Mpc, which uses the Multi-Phase Particle Integrator (MUPPI) for star formation and stellar feedback, with the grasil-3d radiative transfer code that includes reprocessing of UV light by dust. Physical properties of our sample of ˜500 galaxies resemble observed ones, though with some tension at small and large stellar masses. Comparing predicted SEDs of simulated galaxies with different samples of local galaxies, we find that these resemble observed ones, when normalized at 3.6 μm. A comparison with the Herschel Reference Survey shows that the average SEDs of galaxies, divided in bins of star formation rate (SFR), are reproduced in shape and absolute normalization to within a factor of ˜2, while average SEDs of galaxies divided in bins of stellar mass show tensions that are an effect of the difference of simulated and observed galaxies in the stellar mass-SFR plane. We use our sample to investigate the correlation of IR luminosity in Spitzer and Herschel bands with several galaxy properties. SFR is the quantity that best correlates with IR light up to 160 μm, while at longer wavelengths better correlations are found with molecular mass and, at 500 μm, with dust mass. However, using the position of the FIR peak as a proxy for cold dust temperature, we assess that heating of cold dust is mostly determined by SFR, with stellar mass giving only a minor contribution. We finally show how our sample of simulated galaxies can be used as a guide to understand the physical properties and selection biases of observed samples.

Water-budgets and recharge-area simulations for the Spring Creek and Nittany Creek Basins and parts of the Spruce Creek Basin, Centre and Huntingdon Counties, Pennsylvania, Water Years 2000–06

USGS Publications Warehouse

Fulton, John W.; Risser, Dennis W.; Regan, R. Steve; Walker, John F.; Hunt, Randall J.; Niswonger, Richard G.; Hoffman, Scott A.; Markstrom, Steven

2015-08-17

This report describes the results of a study by the U.S. Geological Survey in cooperation with ClearWater Conservancy and the Pennsylvania Department of Environmental Protection to develop a hydrologic model to simulate a water budget and identify areas of greater than average recharge for the Spring Creek Basin in central Pennsylvania. The model was developed to help policy makers, natural resource managers, and the public better understand and manage the water resources in the region. The Groundwater and Surface-water FLOW model (GSFLOW), which is an integration of the Precipitation-Runoff Modeling System (PRMS) and the Modular Groundwater Flow Model (MODFLOW-NWT), was used to simulate surface water and groundwater in the Spring Creek Basin for water years 2000–06. Because the groundwater and surface-water divides for the Spring Creek Basin do not coincide, the study area includes the Nittany Creek Basin and headwaters of the Spruce Creek Basin. The hydrologic model was developed by the use of a stepwise process: (1) develop and calibrate a PRMS model and steady-state MODFLOW-NWT model; (2) re-calibrate the steady-state MODFLOW-NWT model using potential recharge estimates simulated from the PRMS model, and (3) integrate the PRMS and MODFLOW-NWT models into GSFLOW. The individually calibrated PRMS and MODFLOW-NWT models were used as a starting point for the calibration of the fully coupled GSFLOW model. The GSFLOW model calibration was done by comparing observations and corresponding simulated values of streamflow from 11 streamgages and groundwater levels from 16 wells. The cumulative water budget and individual water budgets for water years 2000–06 were simulated by using GSFLOW. The largest source and sink terms are represented by precipitation and evapotranspiration, respectively. For the period simulated, a net surplus in the water budget was computed where inflows exceeded outflows by about 1.7 billion cubic feet (0.47 inches per year over the basin area

A 20-year simulated climatology of global dust aerosol deposition.

PubMed

Zheng, Yu; Zhao, Tianliang; Che, Huizheng; Liu, Yu; Han, Yongxiang; Liu, Chong; Xiong, Jie; Liu, Jianhui; Zhou, Yike

2016-07-01

Based on a 20-year (1991-2010) simulation of dust aerosol deposition with the global climate model CAM5.1 (Community Atmosphere Model, version 5.1), the spatial and temporal variations of dust aerosol deposition were analyzed using climate statistical methods. The results indicated that the annual amount of global dust aerosol deposition was approximately 1161±31Mt, with a decreasing trend, and its interannual variation range of 2.70% over 1991-2010. The 20-year average ratio of global dust dry to wet depositions was 1.12, with interannual variation of 2.24%, showing the quantity of dry deposition of dust aerosol was greater than dust wet deposition. High dry deposition was centered over continental deserts and surrounding regions, while wet deposition was a dominant deposition process over the North Atlantic, North Pacific and northern Indian Ocean. Furthermore, both dry and wet deposition presented a zonal distribution. To examine the regional changes of dust aerosol deposition on land and sea areas, we chose the North Atlantic, Eurasia, northern Indian Ocean, North Pacific and Australia to analyze the interannual and seasonal variations of dust deposition and dry-to-wet deposition ratio. The deposition amounts of each region showed interannual fluctuations with the largest variation range at around 26.96% in the northern Indian Ocean area, followed by the North Pacific (16.47%), Australia (9.76%), North Atlantic (9.43%) and Eurasia (6.03%). The northern Indian Ocean also had the greatest amplitude of interannual variation in dry-to-wet deposition ratio, at 22.41%, followed by the North Atlantic (9.69%), Australia (6.82%), North Pacific (6.31%) and Eurasia (4.36%). Dust aerosol presented a seasonal cycle, with typically strong deposition in spring and summer and weak deposition in autumn and winter. The dust deposition over the northern Indian Ocean exhibited the greatest seasonal change range at about 118.00%, while the North Atlantic showed the lowest seasonal

High Fidelity, Fuel-Like Thermal Simulators for Non-Nuclear Testing: Analysis and Initial Test Results

NASA Technical Reports Server (NTRS)

Bragg-Sitton, Shannon M.; Dickens, Ricky; Dixon, David; Kapernick, Richard

2007-01-01

Non-nuclear testing can be a valuable tool in the development of a space nuclear power system, providing system characterization data and allowing one to work through various fabrication, assembly and integration issues without the cost and time associated with a full ground nuclear test. In a non-nuclear test bed, electric heaters are used to simulate the heat from nuclear fuel. Testing with non-optimized heater elements allows one to assess thermal, heat transfer. and stress related attributes of a given system, but fails to demonstrate the dynamic response that would be present in an integrated, fueled reactor system. High fidelity thermal simulators that match both the static and the dynamic fuel pin performance that would be observed in an operating, fueled nuclear reactor can vastly increase the value of non-nuclear test results. With optimized simulators, the integration of thermal hydraulic hardware tests with simulated neutronic response provides a bridge between electrically heated testing and fueled nuclear testing. By implementing a neutronic response model to simulate the dynamic response that would be expected in a fueled reactor system, one can better understand system integration issues, characterize integrated system response times and response characteristics and assess potential design improvements at relatively small fiscal investment. Initial conceptual thermal simulator designs are determined by simple one-dimensional analysis at a single axial location and at steady state conditions; feasible concepts are then input into a detailed three-dimensional model for comparison to expected fuel pin performance. Static and dynamic fuel pin performance for a proposed reactor design is determined using SINDA/FLUINT thermal analysis software, and comparison is made between the expected nuclear performance and the performance of conceptual thermal simulator designs. Through a series of iterative analyses, a conceptual high fidelity design is developed

Simulation of Cross-border Impacts Resulting from Classical Swine Fever Epidemics within the Netherlands and Germany.

PubMed

Hop, G E; Mourits, M C M; Oude Lansink, A G J M; Saatkamp, H W

2016-02-01

The cross-border region of the Netherlands (NL) and the two German states of North Rhine Westphalia (NRW) and Lower Saxony (LS) is a large and highly integrated livestock production area. This region increasingly develops towards a single epidemiological area in which disease introduction is a shared veterinary and, consequently, economic risk. The objectives of this study were to examine classical swine fever (CSF) control strategies' veterinary and direct economic impacts for NL, NRW and LS given the current production structure and to analyse CSF's cross-border causes and impacts within the NL-NRW-LS region. The course of the epidemic was simulated by the use of InterSpread Plus, whereas economic analysis was restricted to calculating disease control costs and costs directly resulting from the control measures applied. Three veterinary control strategies were considered: a strategy based on the minimum EU requirements, a vaccination and a depopulation strategy based on NL and GER's contingency plans. Regardless of the veterinary control strategy, simulated outbreak sizes and durations for 2010 were much smaller than those simulated previously, using data from over 10 years ago. For example, worst-case outbreaks (50th percentile) in NL resulted in 30-40 infected farms and lasted for two to four and a half months; associated direct costs and direct consequential costs ranged from €24.7 to 28.6 million and €11.7 to 26.7 million, respectively. Both vaccination and depopulation strategies were efficient in controlling outbreaks, especially large outbreaks, whereas the EU minimum strategy was especially deficient in controlling worst-case outbreaks. Both vaccination and depopulation strategies resulted in low direct costs and direct consequential costs. The probability of cross-border disease spread was relatively low, and cross-border spread resulted in small, short outbreaks in neighbouring countries. Few opportunities for further cross-border harmonization and

Simulated Citizen: How Students Experienced a Semester Length Legislative Simulation

ERIC Educational Resources Information Center

Ganzler, Louis M.

2010-01-01

This collective case study contains the results of year-long inquiry into how students experienced a semester length legislative simulation that was rife with political conflict. Specifically the study sought to determine: what teaching strategies were employed, what role conflict played in affecting students' political engagement, and what the…

JT9D performance deterioration results from a simulated aerodynamic load test

NASA Technical Reports Server (NTRS)

Stakolich, E. G.; Stromberg, W. J.

1981-01-01

The results of testing to identify the effects of simulated aerodynamic flight loads on JT9D engine performance are presented. The test results were also used to refine previous analytical studies on the impact of aerodynamic flight loads on performance losses. To accomplish these objectives, a JT9D-7AH engine was assembled with average production clearances and new seals as well as extensive instrumentation to monitor engine performance, case temperatures, and blade tip clearance changes. A special loading device was designed and constructed to permit application of known moments and shear forces to the engine by the use of cables placed around the flight inlet. The test was conducted in the Pratt & Whitney Aircraft X-Ray Test Facility to permit the use of X-ray techniques in conjunction with laser blade tip proximity probes to monitor important engine clearance changes. Upon completion of the test program, the test engine was disassembled, and the condition of gas path parts and final clearances were documented. The test results indicate that the engine lost 1.1 percent in thrust specific fuel consumption (TSFC), as measured under sea level static conditions, due to increased operating clearances caused by simulated flight loads. This compares with 0.9 percent predicted by the analytical model and previous study efforts.

Simulated cosmic microwave background maps at 0.5 deg resolution: Basic results

NASA Technical Reports Server (NTRS)

Hinshaw, G.; Bennett, C. L.; Kogut, A.

1995-01-01

We have simulated full-sky maps of the cosmic microwave background (CMB) anisotropy expected from cold dark matter (CDM) models at 0.5 deg and 1.0 deg angular resolution. Statistical properties of the maps are presented as a function of sky coverage, angular resolution, and instrument noise, and the implications of these results for observability of the Doppler peak are discussed. The rms fluctuations in a map are not a particularly robust probe of the existence of a Doppler peak; however, a full correlation analysis can provide reasonable sensitivity. We find that sensitivity to the Doppler peak depends primarily on the fraction of sky covered, and only secondarily on the angular resolution and noise level. Color plates of the simulated maps are presented to illustrate the anisotropies.

The Titan Haze Simulation Experiment: Latest Laboratory Results and Dedicated Plasma Chemistry Model

NASA Astrophysics Data System (ADS)

Sciamma-O'Brien, Ella; Raymond, Alexander; Mazur, Eric; Salama, Farid

2017-06-01

In Titan’s atmosphere, a complex organic chemistry occurs between its main constituents, N2 and CH4, and leads to the production of larger molecules and solid aerosols.Here, we present the latest results on the gas and solid phase analyses in the Titan Haze Simulation (THS) experiment, developed on the NASA Ames COSmIC simulation chamber. The THS is a unique experimental platform that allows us to simulate Titan’s atmospheric chemistry at Titan-like temperature (200K) by cooling down N2-CH4-based mixtures in a supersonic expansion before inducing the chemistry by plasma. Because of the accelerated gas flow in the expansion, the residence time of the gas in the active plasma region is less than 3 µs. This results in a truncated chemistry that enables us to monitor the first and intermediate steps of the chemistry as well as specific chemical pathways when adding, in the initial gas mixture, heavier molecules that have been detected as trace elements on Titan[1].We discuss the results of recent Mid-infrared (MIR) spectroscopy[2] and X-ray Absorption Near Edge Structure spectroscopy studies of THS Titan tholins produced in different gas mixtures (with and without acetylene and benzene). Both studies have shown the presence of nitrogen chemistry, and differences in the level and nature of the nitrogen incorporation depending on the initial gas mixture. A comparison of THS MIR spectra to VIMS data has shown that the THS aerosols produced in simpler mixtures, i.e., that contain more nitrogen and where the N-incorporation is in isocyanide-type molecules instead of nitriles, are more representative of Titan’s aerosols.In addition, a new model has been developed to simulate the plasma chemistry in the THS. Electron impact and chemical kinetics equations for more than 120 species are followed. The calculated mass spectra are in good agreement with the experimental THS mass spectra[1], confirming that the short residence time in the plasma cavity limits the growth of

The Titan Haze Simulation Experiment: Latest Laboratory Results and Dedicated Plasma Chemistry Model

NASA Astrophysics Data System (ADS)

Sciamma-O'Brien, Ella; Raymond, Alexander; Mazur, Eric; Salama, Farid

2017-10-01

Here, we present the latest results on the gas- and solid phase analyses in the Titan Haze Simulation (THS) experiment, developed at the NASA Ames COSmIC simulation chamber. The THS is a unique experimental platform that allows us to simulate Titan’s complex atmospheric chemistry at Titan-like temperature (200 K) by cooling down N2-CH4-based mixtures in a supersonic expansion before inducing the chemistry by plasma. Because of the accelerated gas flow in the expansion, the residence time of the gas in the active plasma region is less than 3 µs. This results in a truncated chemistry that enables us to control how far in the chain of chemical reactions chemistry processes[1], by adding, in the initial gas mixture, heavier molecules that have been detected as trace elements on Titan.We discuss the results of recent Mid-infrared (MIR) spectroscopy[2] and X-ray Absorption Near Edge Structure spectroscopy studies of THS Titan tholins produced in different gas mixtures (with and without acetylene and benzene). Both studies have shown the presence of nitrogen chemistry, and differences in the level and nature of the nitrogen incorporation depending on the initial gas mixture. A comparison of THS MIR spectra to VIMS data has shown that the THS aerosols produced in simpler mixtures, i.e., that contain more nitrogen and where the N-incorporation is in isocyanide-type molecules instead of nitriles, are more representative of Titan’s aerosols.In addition, a new model has been developed to simulate the plasma chemistry in the THS. Electron impact and chemical kinetics equations for more than 120 species are followed. The calculated mass spectra[3] are in good agreement with the experimental THS mass spectra[1], confirming that the short residence time in the plasma cavity limits the growth of larger species and results in a truncated chemistry, a main feature of the THS.References:[1] Sciamma-O'Brien E. et al., Icarus, 243, 325 (2014)[2] Sciamma-O'Brien E. et al., Icarus

Predicting the Burden of Revision Knee Arthroplasty: Simulation of a 20-Year Horizon.

PubMed

Guerrero-Ludueña, Richard E; Comas, Mercè; Espallargues, Mireia; Coll, Moisès; Pons, Miquel; Sabatés, Santiago; Allepuz, Alejandro; Castells, Xavier

2016-01-01

To estimate future utilization scenarios for knee arthroplasty (KA) revision in the Spanish National Health System in the short- and long-term and their impact on primary KA utilization. A discrete-event simulation model was built to represent KA utilization for 20 years (2012-2031) in the Spanish National Health System. Data on KA utilization from 1997 to 2011 were obtained from the minimum data set. Three scenarios of future utilization of primary KA (1, fixed number since 2011; 2, fixed age- and sex-adjusted rates since 2011; and 3, projection using a linear regression model) were combined with two prosthesis survival functions (W [worse survival], from a study including primary KA from 1995 to 2000; and B [better survival], from the Catalan Registry of Arthroplasty, including primary KA from 2005 to 2013). The simulation results were analyzed in the short-term (2015) and the long-term (2030). Variations in the number of revisions depended on both the primary utilization rate and the survival function applied, ranging from increases of 8.3% to 31.6% in the short- term and from 38.3% to 176.9% in the long-term, corresponding to scenarios 1-B and 3-W, respectively. The prediction of increases in overall surgeries ranged from 0.1% to 22.3% in the short-term and from 3.7% to 98.2% in the long-term. Projections of the burden of KA provide a quantitative basis for future policy decisions on the concentration of high-complexity procedures, the number of orthopedic surgeons required to perform these procedures, and the resources needed. Copyright © 2016 International Society for Pharmacoeconomics and Outcomes Research (ISPOR). Published by Elsevier Inc. All rights reserved.

Direct Numerical Simulation of Liquid Nozzle Spray with Comparison to Shadowgraphy and X-Ray Computed Tomography Experimental Results

NASA Astrophysics Data System (ADS)

van Poppel, Bret; Owkes, Mark; Nelson, Thomas; Lee, Zachary; Sowell, Tyler; Benson, Michael; Vasquez Guzman, Pablo; Fahrig, Rebecca; Eaton, John; Kurman, Matthew; Kweon, Chol-Bum; Bravo, Luis

2014-11-01

In this work, we present high-fidelity Computational Fluid Dynamics (CFD) results of liquid fuel injection from a pressure-swirl atomizer and compare the simulations to experimental results obtained using both shadowgraphy and phase-averaged X-ray computed tomography (CT) scans. The CFD and experimental results focus on the dense near-nozzle region to identify the dominant mechanisms of breakup during primary atomization. Simulations are performed using the NGA code of Desjardins et al (JCP 227 (2008)) and employ the volume of fluid (VOF) method proposed by Owkes and Desjardins (JCP 270 (2013)), a second order accurate, un-split, conservative, three-dimensional VOF scheme providing second order density fluxes and capable of robust and accurate high density ratio simulations. Qualitative features and quantitative statistics are assessed and compared for the simulation and experimental results, including the onset of atomization, spray cone angle, and drop size and distribution.

An experimental investigation into the extent social evaluation anxiety impairs performance in simulation-based learning environments amongst final-year undergraduate nursing students.

PubMed

Mills, Brennen; Carter, Owen; Rudd, Cobie; Claxton, Louise; O'Brien, Robert

2016-10-01

While numerous theoretical and conceptual models suggest social evaluation anxiety would likely influence performance in simulation-based learning environments, there has been surprisingly little research to investigate the extent to which this is true. Final-year Bachelor of Science (Nursing) students (N=70) were randomly assigned to complete one of three clinically identical simulation-based scenarios designed to elicit varying levels of social evaluation anxiety by manipulating the number of other people present with the student during the simulation (1, 2 or 3 others). Rises in acute stress were measured via continuous heart-rate and salivary cortisol. Performance scores were derived from the average of two independent raters' using a structured clinical checklist (/16). Statistically different increases were found within the first minute of the simulation between those students with one versus three other people in the room (+4.13 vs. +14.01beats-per-minute respectively, p=0.01) and salivary cortisol measures suggested significantly different changes in anxiety between these groups (-0.05 vs. +0.11μg/dL respectively, p=0.02). Independent assessments suggested students with only one other person accompanying them in the simulation significantly outperformed those accompanied by three others (12.95 vs. 10.67 respectively, p=0.03). Students accompanied by greater numbers during simulations experienced measurably greater anxiety and measurably poorer performances. These results demonstrate the ability to manipulate social evaluation anxiety within high-fidelity simulation training of undergraduates in order to help students better acclimatise to stressful events prior to practising in real clinical settings. Copyright © 2016 Elsevier Ltd. All rights reserved.

Results from Two Years of Web-Based Astronomy Teaching

NASA Astrophysics Data System (ADS)

Wallin, J.

1996-12-01

During the last two years, course notes, supplemental material, bulletin boards, and an interactive quiz system have been developed for the introductory astronomy course at George Mason University. In this talk, I will present results about the level of Web literacy, Web usage, and educational effectiveness of this system based on in-class surveys and test results. The results presented are based on a 300 person survey course composed primarily of non-science majors. Although this course currently includes a lecture section, we plan to offer this as a web-based distance learning course within six months.

A Novel Simulation Technician Laboratory Design: Results of a Survey-Based Study.

PubMed

Ahmed, Rami; Hughes, Patrick G; Friedl, Ed; Ortiz Figueroa, Fabiana; Cepeda Brito, Jose R; Frey, Jennifer; Birmingham, Lauren E; Atkinson, Steven Scott

2016-03-16

OBJECTIVE : The purpose of this study was to elicit feedback from simulation technicians prior to developing the first simulation technician-specific simulation laboratory in Akron, OH. Simulation technicians serve a vital role in simulation centers within hospitals/health centers around the world. The first simulation technician degree program in the US has been approved in Akron, OH. To satisfy the requirements of this program and to meet the needs of this special audience of learners, a customized simulation lab is essential. A web-based survey was circulated to simulation technicians prior to completion of the lab for the new program. The survey consisted of questions aimed at identifying structural and functional design elements of a novel simulation center for the training of simulation technicians. Quantitative methods were utilized to analyze data. Over 90% of technicians (n=65) think that a lab designed explicitly for the training of technicians is novel and beneficial. Approximately 75% of respondents think that the space provided appropriate audiovisual (AV) infrastructure and space to evaluate the ability of technicians to be independent. The respondents think that the lab needed more storage space, visualization space for a large number of students, and more space in the technical/repair area. CONCLUSIONS : A space designed for the training of simulation technicians was considered to be beneficial. This laboratory requires distinct space for technical repair, adequate bench space for the maintenance and repair of simulators, an appropriate AV infrastructure, and space to evaluate the ability of technicians to be independent.

UAS in the NAS - Analysis Results and Recommendations for Integration of CNPC and ATC Communications Simulation Report

NASA Technical Reports Server (NTRS)

Kubat, Gregory

2016-01-01

This report addresses a deliverable to the UAS-in-the-NAS project for recommendations for integration of CNPC and ATC communications based on analysis results from modeled radio system and NAS-wide UA communication architecture simulations. For each recommendation, a brief explanation of the rationale for its consideration is provided with any supporting results obtained or observed in our simulation activity.

How do rigid-lid assumption affect LES simulation results at high Reynolds flows?

NASA Astrophysics Data System (ADS)

Khosronejad, Ali; Farhadzadeh, Ali; SBU Collaboration

2017-11-01

This research is motivated by the work of Kara et al., JHE, 2015. They employed LES to model flow around a model of abutment at a Re number of 27,000. They showed that first-order turbulence characteristics obtained by rigid-lid (RL) assumption compares fairly well with those of level-set (LS) method. Concerning the second-order statistics, however, their simulation results showed a significant dependence on the method used to describe the free surface. This finding can have important implications for open channel flow modeling. The Reynolds number for typical open channel flows, however, could be much larger than that of Kara et al.'s test case. Herein, we replicate the reported study by augmenting the geometric and hydraulic scales to reach a Re number of one order of magnitude larger ( 200,000). The Virtual Flow Simulator (VFS-Geophysics) model in its LES mode is used to simulate the test case using both RL and LS methods. The computational results are validated using measured flow and free-surface data from our laboratory experiments. Our goal is to investigate the effects of RL assumption on both first-order and second order statistics at high Reynolds numbers that occur in natural waterways. Acknowledgment: Computational resources are provided by the Center of Excellence in Wireless & Information Technology (CEWIT) of Stony Brook University.

Simulation and Feedback in Health Education: A Mixed Methods Study Comparing Three Simulation Modalities.

PubMed

Tait, Lauren; Lee, Kenneth; Rasiah, Rohan; Cooper, Joyce M; Ling, Tristan; Geelan, Benjamin; Bindoff, Ivan

2018-05-03

Background . There are numerous approaches to simulating a patient encounter in pharmacy education. However, little direct comparison between these approaches has been undertaken. Our objective was to investigate student experiences, satisfaction, and feedback preferences between three scenario simulation modalities (paper-, actor-, and computer-based). Methods . We conducted a mixed methods study with randomized cross-over of simulation modalities on final-year Australian graduate-entry Master of Pharmacy students. Participants completed case-based scenarios within each of three simulation modalities, with feedback provided at the completion of each scenario in a format corresponding to each simulation modality. A post-simulation questionnaire collected qualitative and quantitative responses pertaining to participant satisfaction, experiences, and feedback preferences. Results . Participants reported similar levels satisfaction across all three modalities. However, each modality resulted in unique positive and negative experiences, such as student disengagement with paper-based scenarios. Conclusion . Importantly, the themes of guidance and opportunity for peer discussion underlie the best forms of feedback for students. The provision of feedback following simulation should be carefully considered and delivered, with all three simulation modalities producing both positive and negative experiences in regard to their feedback format.

Cognitive, Social, and Literacy Competencies: The Chelsea Bank Simulation Project. Year One: Final Report. [Volume 2]: Appendices.

ERIC Educational Resources Information Center

Duffy, Thomas; And Others

This supplementary volume presents appendixes A-E associated with a 1-year study which determined what secondary school students were doing as they engaged in the Chelsea Bank computer software simulation activities. Appendixes present the SCANS Analysis Coding Sheet; coding problem analysis of 50 video segments; student and teacher interview…

Dark Energy Survey Year 1 results: cross-correlation redshifts - methods and systematics characterization

NASA Astrophysics Data System (ADS)

Gatti, M.; Vielzeuf, P.; Davis, C.; Cawthon, R.; Rau, M. M.; DeRose, J.; De Vicente, J.; Alarcon, A.; Rozo, E.; Gaztanaga, E.; Hoyle, B.; Miquel, R.; Bernstein, G. M.; Bonnett, C.; Carnero Rosell, A.; Castander, F. J.; Chang, C.; da Costa, L. N.; Gruen, D.; Gschwend, J.; Hartley, W. G.; Lin, H.; MacCrann, N.; Maia, M. A. G.; Ogando, R. L. C.; Roodman, A.; Sevilla-Noarbe, I.; Troxel, M. A.; Wechsler, R. H.; Asorey, J.; Davis, T. M.; Glazebrook, K.; Hinton, S. R.; Lewis, G.; Lidman, C.; Macaulay, E.; Möller, A.; O'Neill, C. R.; Sommer, N. E.; Uddin, S. A.; Yuan, F.; Zhang, B.; Abbott, T. M. C.; Allam, S.; Annis, J.; Bechtol, K.; Brooks, D.; Burke, D. L.; Carollo, D.; Carrasco Kind, M.; Carretero, J.; Cunha, C. E.; D'Andrea, C. B.; DePoy, D. L.; Desai, S.; Eifler, T. F.; Evrard, A. E.; Flaugher, B.; Fosalba, P.; Frieman, J.; García-Bellido, J.; Gerdes, D. W.; Goldstein, D. A.; Gruendl, R. A.; Gutierrez, G.; Honscheid, K.; Hoormann, J. K.; Jain, B.; James, D. J.; Jarvis, M.; Jeltema, T.; Johnson, M. W. G.; Johnson, M. D.; Krause, E.; Kuehn, K.; Kuhlmann, S.; Kuropatkin, N.; Li, T. S.; Lima, M.; Marshall, J. L.; Melchior, P.; Menanteau, F.; Nichol, R. C.; Nord, B.; Plazas, A. A.; Reil, K.; Rykoff, E. S.; Sako, M.; Sanchez, E.; Scarpine, V.; Schubnell, M.; Sheldon, E.; Smith, M.; Smith, R. C.; Soares-Santos, M.; Sobreira, F.; Suchyta, E.; Swanson, M. E. C.; Tarle, G.; Thomas, D.; Tucker, B. E.; Tucker, D. L.; Vikram, V.; Walker, A. R.; Weller, J.; Wester, W.; Wolf, R. C.

2018-06-01

We use numerical simulations to characterize the performance of a clustering-based method to calibrate photometric redshift biases. In particular, we cross-correlate the weak lensing source galaxies from the Dark Energy Survey Year 1 sample with redMaGiC galaxies (luminous red galaxies with secure photometric redshifts) to estimate the redshift distribution of the former sample. The recovered redshift distributions are used to calibrate the photometric redshift bias of standard photo-z methods applied to the same source galaxy sample. We apply the method to two photo-z codes run in our simulated data: Bayesian Photometric Redshift and Directional Neighbourhood Fitting. We characterize the systematic uncertainties of our calibration procedure, and find that these systematic uncertainties dominate our error budget. The dominant systematics are due to our assumption of unevolving bias and clustering across each redshift bin, and to differences between the shapes of the redshift distributions derived by clustering versus photo-zs. The systematic uncertainty in the mean redshift bias of the source galaxy sample is Δz ≲ 0.02, though the precise value depends on the redshift bin under consideration. We discuss possible ways to mitigate the impact of our dominant systematics in future analyses.

Simulating Pacific Northwest Forest Response to Climate Change: How We Made Model Results Useful for Vulnerability Assessments

NASA Astrophysics Data System (ADS)

Kim, J. B.; Kerns, B. K.; Halofsky, J.

2014-12-01

GCM-based climate projections and downscaled climate data proliferate, and there are many climate-aware vegetation models in use by researchers. Yet application of fine-scale DGVM based simulation output in national forest vulnerability assessments is not common, because there are technical, administrative and social barriers for their use by managers and policy makers. As part of a science-management climate change adaptation partnership, we performed simulations of vegetation response to climate change for four national forests in the Blue Mountains of Oregon using the MC2 dynamic global vegetation model (DGVM) for use in vulnerability assessments. Our simulation results under business-as-usual scenarios suggest a starkly different future forest conditions for three out of the four national forests in the study area, making their adoption by forest managers a potential challenge. However, using DGVM output to structure discussion of potential vegetation changes provides a suitable framework to discuss the dynamic nature of vegetation change compared to using more commonly available model output (e.g. species distribution models). From the onset, we planned and coordinated our work with national forest managers to maximize the utility and the consideration of the simulation results in planning. Key lessons from this collaboration were: (1) structured and strategic selection of a small number climate change scenarios that capture the range of variability in future conditions simplified results; (2) collecting and integrating data from managers for use in simulations increased support and interest in applying output; (3) a structured, regionally focused, and hierarchical calibration of the DGVM produced well-validated results; (4) simple approaches to quantifying uncertainty in simulation results facilitated communication; and (5) interpretation of model results in a holistic context in relation to multiple lines of evidence produced balanced guidance. This latest

Stratospheric temperatures and tracer transport in a nudged 4-year middle atmosphere GCM simulation

NASA Astrophysics Data System (ADS)

van Aalst, M. K.; Lelieveld, J.; Steil, B.; Brühl, C.; Jöckel, P.; Giorgetta, M. A.; Roelofs, G.-J.

2005-02-01

We have performed a 4-year simulation with the Middle Atmosphere General Circulation Model MAECHAM5/MESSy, while slightly nudging the model's meteorology in the free troposphere (below 113 hPa) towards ECMWF analyses. We show that the nudging 5 technique, which leaves the middle atmosphere almost entirely free, enables comparisons with synoptic observations. The model successfully reproduces many specific features of the interannual variability, including details of the Antarctic vortex structure. In the Arctic, the model captures general features of the interannual variability, but falls short in reproducing the timing of sudden stratospheric warmings. A 10 detailed comparison of the nudged model simulations with ECMWF data shows that the model simulates realistic stratospheric temperature distributions and variabilities, including the temperature minima in the Antarctic vortex. Some small (a few K) model biases were also identified, including a summer cold bias at both poles, and a general cold bias in the lower stratosphere, most pronounced in midlatitudes. A comparison 15 of tracer distributions with HALOE observations shows that the model successfully reproduces specific aspects of the instantaneous circulation. The main tracer transport deficiencies occur in the polar lowermost stratosphere. These are related to the tropopause altitude as well as the tracer advection scheme and model resolution. The additional nudging of equatorial zonal winds, forcing the quasi-biennial oscillation, sig20 nificantly improves stratospheric temperatures and tracer distributions.

A Software Framework for Aircraft Simulation

NASA Technical Reports Server (NTRS)

Curlett, Brian P.

2008-01-01

The National Aeronautics and Space Administration Dryden Flight Research Center has a long history in developing simulations of experimental fixed-wing aircraft from gliders to suborbital vehicles on platforms ranging from desktop simulators to pilot-in-the-loop/aircraft-in-the-loop simulators. Regardless of the aircraft or simulator hardware, much of the software framework is common to all NASA Dryden simulators. Some of this software has withstood the test of time, but in recent years the push toward high-fidelity user-friendly simulations has resulted in some significant changes. This report presents an overview of the current NASA Dryden simulation software framework and capabilities with an emphasis on the new features that have permitted NASA to develop more capable simulations while maintaining the same staffing levels.

Motion-base simulator results of advanced supersonic transport handling qualities with active controls

NASA Technical Reports Server (NTRS)

Feather, J. B.; Joshi, D. S.

1981-01-01

Handling qualities of the unaugmented advanced supersonic transport (AST) are deficient in the low-speed, landing approach regime. Consequently, improvement in handling with active control augmentation systems has been achieved using implicit model-following techniques. Extensive fixed-based simulator evaluations were used to validate these systems prior to tests with full motion and visual capabilities on a six-axis motion-base simulator (MBS). These tests compared the handling qualities of the unaugmented AST with several augmented configurations to ascertain the effectiveness of these systems. Cooper-Harper ratings, tracking errors, and control activity data from the MBS tests have been analyzed statistically. The results show the fully augmented AST handling qualities have been improved to an acceptable level.

Comparison of simulation and experimental results for a gas puff nozzle on Ambiorix

DOE Office of Scientific and Technical Information (OSTI.GOV)

Barnier, J-N.; Chevalier, J-M.; Dubroca, B.

One of source term of Z-Pinch experiments is the gas puff density profile. In order to characterize the gas jet, an experiment based on interferometry has been performed. The first study was a point measurement (a section density profile) which led us to develop a global and instantaneous interferometry imaging method. In order to optimise the nozzle, we simulated the experiment with a flow calculation code (ARES). In this paper, the experimental results are compared with simulations. The different gas properties (He, Ne, Ar) and the flow duration lead us to take care, on the one hand, of the gasmore » viscosity, and on the other, of modifying the code for an instationary flow.« less

A comparison of results from two simulators used for studies of astronaut maneuvering units. [with application to Skylab program

NASA Technical Reports Server (NTRS)

Stewart, E. C.; Cannaday, R. L.

1973-01-01

A comparison of the results from a fixed-base, six-degree-of -freedom simulator and a moving-base, three-degree-of-freedom simulator was made for a close-in, EVA-type maneuvering task in which visual cues of a target spacecraft were used for guidance. The maneuvering unit (the foot-controlled maneuvering unit of Skylab Experiment T020) employed an on-off acceleration command control system operated entirely by the feet. Maneuvers by two test subjects were made for the fixed-base simulator in six and three degrees of freedom and for the moving-base simulator in uncontrolled and controlled, EVA-type visual cue conditions. Comparisons of pilot ratings and 13 different quantitative parameters from the two simulators are made. Different results were obtained from the two simulators, and the effects of limited degrees of freedom and uncontrolled visual cues are discussed.

Research on an expert system for database operation of simulation-emulation math models. Volume 1, Phase 1: Results

NASA Technical Reports Server (NTRS)

Kawamura, K.; Beale, G. O.; Schaffer, J. D.; Hsieh, B. J.; Padalkar, S.; Rodriguez-Moscoso, J. J.

1985-01-01

The results of the first phase of Research on an Expert System for Database Operation of Simulation/Emulation Math Models, is described. Techniques from artificial intelligence (AI) were to bear on task domains of interest to NASA Marshall Space Flight Center. One such domain is simulation of spacecraft attitude control systems. Two related software systems were developed to and delivered to NASA. One was a generic simulation model for spacecraft attitude control, written in FORTRAN. The second was an expert system which understands the usage of a class of spacecraft attitude control simulation software and can assist the user in running the software. This NASA Expert Simulation System (NESS), written in LISP, contains general knowledge about digital simulation, specific knowledge about the simulation software, and self knowledge.

Chemical compatibility screening results of plastic packaging to mixed waste simulants

DOE Office of Scientific and Technical Information (OSTI.GOV)

Nigrey, P.J.; Dickens, T.G.

1995-12-01

We have developed a chemical compatibility program for evaluating transportation packaging components for transporting mixed waste forms. We have performed the first phase of this experimental program to determine the effects of simulant mixed wastes on packaging materials. This effort involved the screening of 10 plastic materials in four liquid mixed waste simulants. The testing protocol involved exposing the respective materials to {approximately}3 kGy of gamma radiation followed by 14 day exposures to the waste simulants of 60 C. The seal materials or rubbers were tested using VTR (vapor transport rate) measurements while the liner materials were tested using specificmore » gravity as a metric. For these tests, a screening criteria of {approximately}1 g/m{sup 2}/hr for VTR and a specific gravity change of 10% was used. It was concluded that while all seal materials passed exposure to the aqueous simulant mixed waste, EPDM and SBR had the lowest VTRs. In the chlorinated hydrocarbon simulant mixed waste, only VITON passed the screening tests. In both the simulant scintillation fluid mixed waste and the ketone mixture simulant mixed waste, none of the seal materials met the screening criteria. It is anticipated that those materials with the lowest VTRs will be evaluated in the comprehensive phase of the program. For specific gravity testing of liner materials the data showed that while all materials with the exception of polypropylene passed the screening criteria, Kel-F, HDPE, and XLPE were found to offer the greatest resistance to the combination of radiation and chemicals.« less

Modeling and Simulation at NASA

NASA Technical Reports Server (NTRS)

Steele, Martin J.

2009-01-01

This slide presentation is composed of two topics. The first reviews the use of modeling and simulation (M&S) particularly as it relates to the Constellation program and discrete event simulation (DES). DES is defined as a process and system analysis, through time-based and resource constrained probabilistic simulation models, that provide insight into operation system performance. The DES shows that the cycles for a launch from manufacturing and assembly to launch and recovery is about 45 days and that approximately 4 launches per year are practicable. The second topic reviews a NASA Standard for Modeling and Simulation. The Columbia Accident Investigation Board made some recommendations related to models and simulations. Some of the ideas inherent in the new standard are the documentation of M&S activities, an assessment of the credibility, and reporting to decision makers, which should include the analysis of the results, a statement as to the uncertainty in the results,and the credibility of the results. There is also discussion about verification and validation (V&V) of models. There is also discussion about the different types of models and simulation.

Simulation and experimental results of optical and thermal modeling of gold nanoshells.

PubMed

Ghazanfari, Lida; Khosroshahi, Mohammad E

2014-09-01

This paper proposes a generalized method for optical and thermal modeling of synthesized magneto-optical nanoshells (MNSs) for biomedical applications. Superparamagnetic magnetite nanoparticles with diameter of 9.5 ± 1.4 nm are fabricated using co-precipitation method and subsequently covered by a thin layer of gold to obtain 15.8 ± 3.5 nm MNSs. In this paper, simulations and detailed analysis are carried out for different nanoshell geometry to achieve a maximum heat power. Structural, magnetic and optical properties of MNSs are assessed using vibrating sample magnetometer (VSM), X-ray diffraction (XRD), UV-VIS spectrophotometer, dynamic light scattering (DLS), and transmission electron microscope (TEM). Magnetic saturation of synthesized magnetite nanoparticles are reduced from 46.94 to 11.98 emu/g after coating with gold. The performance of the proposed optical-thermal modeling technique is verified by simulation and experimental results. Copyright © 2014 Elsevier B.V. All rights reserved.

Simulation results of automatic restructurable flight control system concepts

NASA Technical Reports Server (NTRS)

Weiss, J. L.; Looze, D. P.; Eterno, J. S.; Ostroff, A.

1986-01-01

The restructurable flight control system (RFCS) described by Weiss et al. (1986) is reviewed, and several results of an extensive six degrees of freedom nonlinear simulation of several aspects of this system are reported. It is concluded that the nontraditional use of standard control surfaces in a nominal feedback control system to spread control authority among many redundant control elements provides a significant amount of fault tolerance without any use of restructuring techniques. The use of new feedback gains alone following a failure can provide significantly improved recovery as long as the control elements remain within their travel limits and as long as uncertainty about the failure identity is properly handled. The use of the feed-forward trim solution in conjunction with redesigned feedback gains allows recovery to take place even when significant control saturation occurs.

A Compact Synchronous Cellular Model of Nonlinear Calcium Dynamics: Simulation and FPGA Synthesis Results.

PubMed

Soleimani, Hamid; Drakakis, Emmanuel M

2017-06-01

Recent studies have demonstrated that calcium is a widespread intracellular ion that controls a wide range of temporal dynamics in the mammalian body. The simulation and validation of such studies using experimental data would benefit from a fast large scale simulation and modelling tool. This paper presents a compact and fully reconfigurable cellular calcium model capable of mimicking Hopf bifurcation phenomenon and various nonlinear responses of the biological calcium dynamics. The proposed cellular model is synthesized on a digital platform for a single unit and a network model. Hardware synthesis, physical implementation on FPGA, and theoretical analysis confirm that the proposed cellular model can mimic the biological calcium behaviors with considerably low hardware overhead. The approach has the potential to speed up large-scale simulations of slow intracellular dynamics by sharing more cellular units in real-time. To this end, various networks constructed by pipelining 10 k to 40 k cellular calcium units are compared with an equivalent simulation run on a standard PC workstation. Results show that the cellular hardware model is, on average, 83 times faster than the CPU version.

Simulation test results for lift/cruise fan research and technology aircraft

NASA Technical Reports Server (NTRS)

Bland, M. P.; Konsewicz, R. K.

1976-01-01

A flight simulation program was conducted on the flight simulator for advanced aircraft (FSAA). The flight simulation was a part of a contracted effort to provide a lift/cruise fan V/STOL aircraft mathematical model for flight simulation. The simulated aircraft is a configuration of the Lift/Cruise Fan V/STOL research technology aircraft (RTA). The aircraft was powered by three gas generators driving three fans. One lift fan was installed in the nose of the aircraft, and two lift/cruise fans at the wing root. The thrust of these fans was modulated to provide pitch and roll control, and vectored to provide yaw, side force control, and longitudinal translation. Two versions of the RTA were defined. One was powered by the GE J97/LF460 propulsion system which was gas-coupled for power transfer between fans for control. The other version was powered by DDA XT701 gas generators driving 62 inch variable pitch fans. The flight control system in both versions of the RTA was the same.

Simulation Results for Airborne Precision Spacing along Continuous Descent Arrivals

NASA Technical Reports Server (NTRS)

Barmore, Bryan E.; Abbott, Terence S.; Capron, William R.; Baxley, Brian T.

2008-01-01

This paper describes the results of a fast-time simulation experiment and a high-fidelity simulator validation with merging streams of aircraft flying Continuous Descent Arrivals through generic airspace to a runway at Dallas-Ft Worth. Aircraft made small speed adjustments based on an airborne-based spacing algorithm, so as to arrive at the threshold exactly at the assigned time interval behind their Traffic-To-Follow. The 40 aircraft were initialized at different altitudes and speeds on one of four different routes, and then merged at different points and altitudes while flying Continuous Descent Arrivals. This merging and spacing using flight deck equipment and procedures to augment or implement Air Traffic Management directives is called Flight Deck-based Merging and Spacing, an important subset of a larger Airborne Precision Spacing functionality. This research indicates that Flight Deck-based Merging and Spacing initiated while at cruise altitude and well prior to the Terminal Radar Approach Control entry can significantly contribute to the delivery of aircraft at a specified interval to the runway threshold with a high degree of accuracy and at a reduced pilot workload. Furthermore, previously documented work has shown that using a Continuous Descent Arrival instead of a traditional step-down descent can save fuel, reduce noise, and reduce emissions. Research into Flight Deck-based Merging and Spacing is a cooperative effort between government and industry partners.

Improved fourth-year medical student clinical decision-making performance as a resuscitation team leader after a simulation-based curriculum.

PubMed

Ten Eyck, Raymond P; Tews, Matthew; Ballester, John M; Hamilton, Glenn C

2010-06-01

To determine the impact of simulation-based instruction on student performance in the role of emergency department resuscitation team leader. A randomized, single-blinded, controlled study using an intention to treat analysis. Eighty-three fourth-year medical students enrolled in an emergency medicine clerkship were randomly allocated to two groups differing only by instructional format. Each student individually completed an initial simulation case, followed by a standardized curriculum of eight cases in either group simulation or case-based group discussion format before a second individual simulation case. A remote coinvestigator measured eight objective performance end points using digital recordings of all individual simulation cases. McNemar chi2, Pearson correlation, repeated measures multivariate analysis of variance, and follow-up analysis of variance were used for statistical evaluation. Sixty-eight students (82%) completed both initial and follow-up individual simulations. Eight students were lost from the simulation group and seven from the discussion group. The mean postintervention case performance was significantly better for the students allocated to simulation instruction compared with the group discussion students for four outcomes including a decrease in mean time to (1) order an intravenous line; (2) initiate cardiac monitoring; (3) order initial laboratory tests; and (4) initiate blood pressure monitoring. Paired comparisons of each student's initial and follow-up simulations demonstrated significant improvement in the same four areas, in mean time to order an abdominal radiograph and in obtaining an allergy history. A single simulation-based teaching session significantly improved student performance as a team leader. Additional simulation sessions provided further improvement compared with instruction provided in case-based group discussion format.

Dark Energy Survey Year 1 results: the impact of galaxy neighbours on weak lensing cosmology with IM3SHAPE

NASA Astrophysics Data System (ADS)

Samuroff, S.; Bridle, S. L.; Zuntz, J.; Troxel, M. A.; Gruen, D.; Rollins, R. P.; Bernstein, G. M.; Eifler, T. F.; Huff, E. M.; Kacprzak, T.; Krause, E.; MacCrann, N.; Abdalla, F. B.; Allam, S.; Annis, J.; Bechtol, K.; Benoit-Lévy, A.; Bertin, E.; Brooks, D.; Buckley-Geer, E.; Carnero Rosell, A.; Carrasco Kind, M.; Carretero, J.; Crocce, M.; D'Andrea, C. B.; da Costa, L. N.; Davis, C.; Desai, S.; Doel, P.; Fausti Neto, A.; Flaugher, B.; Fosalba, P.; Frieman, J.; García-Bellido, J.; Gerdes, D. W.; Gruendl, R. A.; Gschwend, J.; Gutierrez, G.; Honscheid, K.; James, D. J.; Jarvis, M.; Jeltema, T.; Kirk, D.; Kuehn, K.; Kuhlmann, S.; Li, T. S.; Lima, M.; Maia, M. A. G.; March, M.; Marshall, J. L.; Martini, P.; Melchior, P.; Menanteau, F.; Miquel, R.; Nord, B.; Ogando, R. L. C.; Plazas, A. A.; Roodman, A.; Sanchez, E.; Scarpine, V.; Schindler, R.; Schubnell, M.; Sevilla-Noarbe, I.; Sheldon, E.; Smith, M.; Soares-Santos, M.; Sobreira, F.; Suchyta, E.; Tarle, G.; Thomas, D.; Tucker, D. L.; DES Collaboration

2018-04-01

We use a suite of simulated images based on Year 1 of the Dark Energy Survey to explore the impact of galaxy neighbours on shape measurement and shear cosmology. The HOOPOE image simulations include realistic blending, galaxy positions, and spatial variations in depth and point spread function properties. Using the IM3SHAPE maximum-likelihood shape measurement code, we identify four mechanisms by which neighbours can have a non-negligible influence on shear estimation. These effects, if ignored, would contribute a net multiplicative bias of m ˜ 0.03-0.09 in the Year One of the Dark Energy Survey (DES Y1) IM3SHAPE catalogue, though the precise impact will be dependent on both the measurement code and the selection cuts applied. This can be reduced to percentage level or less by removing objects with close neighbours, at a cost to the effective number density of galaxies neff of 30 per cent. We use the cosmological inference pipeline of DES Y1 to explore the cosmological implications of neighbour bias and show that omitting blending from the calibration simulation for DES Y1 would bias the inferred clustering amplitude S8 ≡ σ8(Ωm/0.3)0.5 by 2σ towards low values. Finally, we use the HOOPOE simulations to test the effect of neighbour-induced spatial correlations in the multiplicative bias. We find the impact on the recovered S8 of ignoring such correlations to be subdominant to statistical error at the current level of precision.

Competency-based learning in an ambulatory care setting: Implementation of simulation training in the Ambulatory Care Rotation during the final year of the MaReCuM model curriculum.

PubMed

Dusch, Martin; Narciß, Elisabeth; Strohmer, Renate; Schüttpelz-Brauns, Katrin

2018-01-01

Aim: As part of the MaReCuM model curriculum at Medical Faculty Mannheim Heidelberg University, a final year rotation in ambulatory care was implemented and augmented to include ambulatory care simulation. In this paper we describe this ambulatory care simulation, the designated competency-based learning objectives, and evaluate the educational effect of the ambulatory care simulation training. Method: Seventy-five final year medical students participated in the survey (response rate: 83%). The control group completed the ambulatory rotation prior to the implementation of the ambulatory care simulation. The experimental group was required to participate in the simulation at the beginning of the final year rotation in ambulatory care. A survey of both groups was conducted at the beginning and at the end of the rotation. The learning objectives were taken from the National Competency-based Catalogue of Learning Objectives for Undergraduate Medical Education (NKLM). Results: The ambulatory care simulation had no measurable influence on students' subjectively perceived learning progress, the evaluation of the ambulatory care rotation, or working in an ambulatory care setting. At the end of the rotation participants in both groups reported having gained better insight into treating outpatients. At the beginning of the rotation members of both groups assessed their competencies to be at the same level. The simulated ambulatory scenarios were evaluated by the participating students as being well structured and easy to understand. The scenarios successfully created a sense of time pressure for those confronted with them. The ability to correctly fill out a narcotic prescription form as required was rated significantly higher by those who participated in the simulation. Participation in the ambulatory care simulation had no effect on the other competencies covered by the survey. Discussion: The effect of the four instructional units comprising the ambulatory care simulation

Expected lifetime numbers, risks, and burden of osteoporotic fractures for 50-year old Chinese women: a discrete event simulation incorporating FRAX.

PubMed

Jiang, Yawen; Ni, Weiyi

2016-11-01

This work was undertaken to provide an estimation of expected lifetime numbers, risks, and burden of fractures for 50-year-old Chinese women. A discrete event simulation model was developed to simulate the lifetime fractures of 50-year-old Chinese women at average risk of osteoporotic fracture. Main events in the model included hip fracture, clinical vertebral fracture, wrist fracture, humerus fracture, and other fracture. Fracture risks were calculated using the FRAX ® tool. Simulations of 50-year-old Chinese women without fracture risks were also carried out as a comparison to determine the burden of fractures. A 50-year-old Chinese woman at average risk of fracture is expected to experience 0.135 (95 % CI: 0.134-0.137) hip fractures, 0.120 (95 % CI: 0.119-0.122) clinical vertebral fractures, 0.095 (95 % CI: 0.094-0.096) wrist fractures, 0.079 (95 % CI: 0.078-0.080) humerus fractures, and 0.407 (95 % CI: 0.404-0.410) other fractures over the remainder of her life. The residual lifetime risk of any fracture, hip fracture, clinical vertebral fracture, wrist fracture, humerus fracture, and other fracture for a 50-year-old Chinese woman is 37.36, 11.77, 10.47, 8.61, 7.30, and 27.80 %, respectively. The fracture-attributable excess quality-adjusted life year (QALY) loss and lifetime costs are estimated at 0.11 QALYs (95 % CI: 0.00-0.22 QALYs) and US $714.61 (95 % CI: US $709.20-720.02), totaling a net monetary benefit loss of US $1,104.43 (95 % CI: US $904.09-1,304.78). Chinese women 50 years of age are at high risk of osteoporotic fracture, and the expected economic and quality-of-life burden attributable to osteoporotic fractures among Chinese women is substantial.

Simulation of Benchmark Cases with the Terminal Area Simulation System (TASS)

NASA Technical Reports Server (NTRS)

Ahmad, Nash'at; Proctor, Fred

2011-01-01

The hydrodynamic core of the Terminal Area Simulation System (TASS) is evaluated against different benchmark cases. In the absence of closed form solutions for the equations governing atmospheric flows, the models are usually evaluated against idealized test cases. Over the years, various authors have suggested a suite of these idealized cases which have become standards for testing and evaluating the dynamics and thermodynamics of atmospheric flow models. In this paper, simulations of three such cases are described. In addition, the TASS model is evaluated against a test case that uses an exact solution of the Navier-Stokes equations. The TASS results are compared against previously reported simulations of these banchmark cases in the literature. It is demonstrated that the TASS model is highly accurate, stable and robust.

Simulation of Benchmark Cases with the Terminal Area Simulation System (TASS)

NASA Technical Reports Server (NTRS)

Ahmad, Nashat N.; Proctor, Fred H.

2011-01-01

The hydrodynamic core of the Terminal Area Simulation System (TASS) is evaluated against different benchmark cases. In the absence of closed form solutions for the equations governing atmospheric flows, the models are usually evaluated against idealized test cases. Over the years, various authors have suggested a suite of these idealized cases which have become standards for testing and evaluating the dynamics and thermodynamics of atmospheric flow models. In this paper, simulations of three such cases are described. In addition, the TASS model is evaluated against a test case that uses an exact solution of the Navier-Stokes equations. The TASS results are compared against previously reported simulations of these benchmark cases in the literature. It is demonstrated that the TASS model is highly accurate, stable and robust.

Caution: Precision Error in Blade Alignment Results in Faulty Unsteady CFD Simulation

NASA Astrophysics Data System (ADS)

Lewis, Bryan; Cimbala, John; Wouden, Alex

2012-11-01

Turbomachinery components experience unsteady loads at several frequencies. The rotor frequency corresponds to the time for one rotor blade to rotate between two stator vanes, and is normally dominant for rotor torque oscillations. The guide vane frequency corresponds to the time for two rotor blades to pass by one guide vane. The machine frequency corresponds to the machine RPM. Oscillations at the machine frequency are always present due to minor blade misalignments and imperfections resulting from manufacturing defects. However, machine frequency oscillations should not be present in CFD simulations if the mesh is free of both blade misalignment and surface imperfections. The flow through a Francis hydroturbine was modeled with unsteady Reynolds-Averaged Navier-Stokes (URANS) CFD simulations and a dynamic rotating grid. Spectral analysis of the unsteady torque on the rotor blades revealed a large component at the machine frequency. Close examination showed that one blade was displaced by 0 .0001° due to round-off errors during mesh generation. A second mesh without blade misalignment was then created. Subsequently, large machine frequency oscillations were not observed for this mesh. These results highlight the effect of minor geometry imperfections on CFD solutions. This research was supported by a grant from the DoE and a National Defense Science and Engineering Graduate Fellowship.

Dark Energy Survey Year 1 Results: Cross-Correlation Redshifts - Methods and Systematics Characterization

DOE PAGES

Gatti, M.

2018-02-22

We use numerical simulations to characterize the performance of a clustering-based method to calibrate photometric redshift biases. In particular, we cross-correlate the weak lensing (WL) source galaxies from the Dark Energy Survey Year 1 (DES Y1) sample with redMaGiC galaxies (luminous red galaxies with secure photometric red- shifts) to estimate the redshift distribution of the former sample. The recovered redshift distributions are used to calibrate the photometric redshift bias of standard photo-z methods applied to the same source galaxy sample. We also apply the method to three photo-z codes run in our simulated data: Bayesian Photometric Redshift (BPZ), Directional Neighborhoodmore » Fitting (DNF), and Random Forest-based photo-z (RF). We characterize the systematic uncertainties of our calibration procedure, and find that these systematic uncertainties dominate our error budget. The dominant systematics are due to our assumption of unevolving bias and clustering across each redshift bin, and to differences between the shapes of the redshift distributions derived by clustering vs photo-z's. The systematic uncertainty in the mean redshift bias of the source galaxy sample is z ≲ 0.02, though the precise value depends on the redshift bin under consideration. Here, we discuss possible ways to mitigate the impact of our dominant systematics in future analyses.« less

Dark Energy Survey Year 1 Results: Cross-Correlation Redshifts - Methods and Systematics Characterization

DOE Office of Scientific and Technical Information (OSTI.GOV)

Gatti, M.

We use numerical simulations to characterize the performance of a clustering-based method to calibrate photometric redshift biases. In particular, we cross-correlate the weak lensing (WL) source galaxies from the Dark Energy Survey Year 1 (DES Y1) sample with redMaGiC galaxies (luminous red galaxies with secure photometric red- shifts) to estimate the redshift distribution of the former sample. The recovered redshift distributions are used to calibrate the photometric redshift bias of standard photo-z methods applied to the same source galaxy sample. We also apply the method to three photo-z codes run in our simulated data: Bayesian Photometric Redshift (BPZ), Directional Neighborhoodmore » Fitting (DNF), and Random Forest-based photo-z (RF). We characterize the systematic uncertainties of our calibration procedure, and find that these systematic uncertainties dominate our error budget. The dominant systematics are due to our assumption of unevolving bias and clustering across each redshift bin, and to differences between the shapes of the redshift distributions derived by clustering vs photo-z's. The systematic uncertainty in the mean redshift bias of the source galaxy sample is z ≲ 0.02, though the precise value depends on the redshift bin under consideration. Here, we discuss possible ways to mitigate the impact of our dominant systematics in future analyses.« less

Simulation-based Mastery Learning Improves Cardiac Auscultation Skills in Medical Students

PubMed Central

McGaghie, William C.; Cohen, Elaine R.; Kaye, Marsha; Wayne, Diane B.

2010-01-01

Background Cardiac auscultation is a core clinical skill. However, prior studies show that trainee skills are often deficient and that clinical experience is not a proxy for competence. Objective To describe a mastery model of cardiac auscultation education and evaluate its effectiveness in improving bedside cardiac auscultation skills. Design Untreated control group design with pretest and posttest. Participants Third-year students who received a cardiac auscultation curriculum and fourth year students who did not. Intervention A cardiac auscultation curriculum consisting of a computer tutorial and a cardiac patient simulator. All third-year students were required to meet or exceed a minimum passing score (MPS) set by an expert panel at posttest. Measurements Diagnostic accuracy with simulated heart sounds and actual patients. Results Trained third-year students (n = 77) demonstrated significantly higher cardiac auscultation accuracy compared to untrained fourth year students (n = 31) in assessment of simulated heart sounds (93.8% vs. 73.9%, p < 0.001) and with real patients (81.8% vs. 75.1%, p = 0.003). USMLE scores correlated modestly with a computer-based multiple choice assessment using simulated heart sounds but not with bedside skills on real patients. Conclusions A cardiac auscultation curriculum consisting of deliberate practice with a computer-based tutorial and a cardiac patient simulator resulted in improved assessment of simulated heart sounds and more accurate examination of actual patients. PMID:20339952

A 12-year (1987-1998) Ensemble Simulation of the US Climate with a Variable Resolution Stretched Grid GCM

NASA Technical Reports Server (NTRS)

Fox-Rabinovitz, Michael S.; Takacs, Lawrence L.; Govindaraju, Ravi C.

2002-01-01

The variable-resolution stretched-grid (SG) GEOS (Goddard Earth Observing System) GCM has been used for limited ensemble integrations with a relatively coarse, 60 to 100 km, regional resolution over the U.S. The experiments have been run for the 12-year period, 1987-1998, that includes the recent ENSO cycles. Initial conditions 1-2 days apart are used for ensemble members. The goal of the experiments is analyzing the long-term SG-GCM ensemble integrations in terms of their potential in reducing the uncertainties of regional climate simulation while producing realistic mesoscales. The ensemble integration results are analyzed for both prognostic and diagnostic fields. A special attention is devoted to analyzing the variability of precipitation over the U.S. The internal variability of the SG-GCM has been assessed. The ensemble means appear to be closer to the verifying analyses than the individual ensemble members. The ensemble means capture realistic mesoscale patterns, especially those of induced by orography. Two ENSO cycles have been analyzed in terms their impact on the U.S. climate, especially on precipitation. The ability of the SG-GCM simulations to produce regional climate anomalies has been confirmed. However, the optimal size of the ensembles depending on fine regional resolution used, is still to be determined. The SG-GCM ensemble simulations are performed as a preparation or a preliminary stage for the international SGMIP (Stretched-Grid Model Intercomparison Project) that is under way with participation of the major centers and groups employing the SG-approach for regional climate modeling.

Low-cost autonomous orbit control about Mars: Initial simulation results

NASA Astrophysics Data System (ADS)

Dawson, S. D.; Early, L. W.; Potterveld, C. W.; Königsmann, H. J.

1999-11-01

Interest in studying the possibility of extraterrestrial life has led to the re-emergence of the Red Planet as a major target of planetary exploration. Currently proposed missions in the post-2000 period are routinely calling for rendezvous with ascent craft, long-term orbiting of, and sample-return from Mars. Such missions would benefit greatly from autonomous orbit control as a means to reduce operations costs and enable contact with Mars ground stations out of view of the Earth. This paper present results from initial simulations of autonomously controlled orbits around Mars, and points out possible uses of the technology and areas of routine Mars operations where such cost-conscious and robust autonomy could prove most effective. These simulations have validated the approach and control philosophies used in the development of this autonomous orbit controller. Future work will refine the controller, accounting for systematic and random errors in the navigation of the spacecraft from the sensor suite, and will produce prototype flight code for inclusion on future missions. A modified version of Microcosm's commercially available High Precision Orbit Propagator (HPOP) was used in the preparation of these results due to its high accuracy and speed of operation. Control laws were developed to allow an autonomously controlled spacecraft to continuously control to a pre-defined orbit about Mars with near-optimal propellant usage. The control laws were implemented as an adjunct to HPOP. The GSFC-produced 50 × 50 field model of the Martian gravitational potential was used in all simulations. The Martian atmospheric drag was modeled using an exponentially decaying atmosphere based on data from the Mars-GRAM NASA Ames model. It is hoped that the simple atmosphere model that was implemented can be significantly improved in the future so as to approach the fidelity of the Mars-GRAM model in its predictions of atmospheric density at orbital altitudes. Such additional work

Assessment of dental caries predictors in 6-year-old school children - results from 5-year retrospective cohort study

PubMed Central

2012-01-01

Background This was a retrospective cohort study undertaken to assess the rate and pattern of dental caries development in 6-year-old school children followed-up for a period of 5 years, and to identify baseline risk factors that were associated with 5 years caries experience in Malaysian children. Methods This 5-years retrospective cohort study comprised primary school children initially aged 6 years in 2004. Caries experience of each child was recorded annually using World Health Organization criteria. The rates of dental caries were recorded in prevalence and incidence density of carious lesions from baseline to final examination. Risk assessment was done to assess relative risk for caries after 5 years in children with baseline caries status. Simple and multiple logistic regression analysis were performed to identify significant independent risk factors for caries. Results The sample consisted of 1830 school children. All components of DMFT showed significant differences between baseline and final examination. Filled teeth (FT) component of the DMFT showed the greatest increases. Results revealed the initial baseline caries level in permanent dentition was a strong predictor for future caries after 5 years (RR=3.78, 95% CI=3.48-4.10, P<0.001). Logistic regression analysis showed significant association between caries occurrence and residence (urban/rural) (OR=1.80, P<0.001). However, it was not significantly associated with gender and ethnicity. The incidence density of caries, affected persons (IDp) observed from baseline and after 5 years was 5.80 persons/100 person-year of observation. The rate of new caries-affected tooth (IDt) in the period from baseline and after 5-years was 0.76 teeth/100 teeth-year of observation. Conclusion The majority of 12-year-old school children (70%) were caries-free and most of the caries were concentrated in only a small proportion (30%) of them. We found that the presence of caries in permanent teeth at the age of 6 years was

Comparison of simulation and experimental results for a model aqueous tert-butanol solution

NASA Astrophysics Data System (ADS)

Overduin, S. D.; Patey, G. N.

2017-07-01

Molecular dynamics simulations are used to investigate the behavior of aqueous tert-butanol (TBA) solutions for a range of temperatures, using the CHARMM generalized force field (CGenFF) to model TBA and the TIP4P/2005 or TIP4P-Ew water model. Simulation results for the density, isothermal compressibility, constant pressure heat capacity, and self-diffusion coefficients are in good accord with experimental measurements. Agreement with the experiment is particularly good at low TBA concentration, where experiments have revealed anomalies in a number of thermodynamic properties. Importantly, the CGenFF model does not exhibit liquid-liquid demixing at temperatures between 290 and 320 K (for systems of 32 000 molecules), in contrast with the situation for several other common TBA models [R. Gupta and G. N. Patey, J. Chem. Phys. 137, 034509 (2012)]. However, whereas real water and TBA are miscible at all temperatures where the liquid is stable, we observe some evidence of demixing at 340 K and above. To evaluate the structural properties at low concentrations, we compare with both neutron scattering and recent spectroscopic measurements. This reveals that while the CGenFF model is a definite improvement over other models that have been considered, the TBA molecules still exhibit a tendency to associate at low concentrations that is somewhat stronger than that indicated by experiments. Finally, we discuss the range and decay times of the long-range correlations, providing an indication of the system size and simulation times that are necessary in order to obtain reliable results for certain properties.

Comparing Results of SPH/N-body Impact Simulations Using Both Solid and Rubble-pile Target Asteroids

NASA Astrophysics Data System (ADS)

Durda, Daniel D.; Bottke, W. F.; Enke, B. L.; Nesvorný, D.; Asphaug, E.; Richardson, D. C.

2006-09-01

We have been investigating the properties of satellites and the morphology of size-frequency distributions (SFDs) resulting from a suite of 160 SPH/N-body simulations of impacts into 100-km diameter parent asteroids (Durda et al. 2004, Icarus 170, 243-257; Durda et al. 2006, Icarus, in press). These simulations have produced many valuable insights into the outcomes of cratering and disruptive impacts but were limited to monolithic basalt targets. As a natural consequence of collisional evolution, however, many asteroids have undergone a series of battering impacts that likely have left their interiors substantially fractured, if not completely rubblized. In light of this, we have re-mapped the matrix of simulations using rubble-pile target objects. We constructed the rubble-pile targets by filling the interior of the 100-km diameter spherical shell (the target envelope) with randomly sized solid spheres in mutual contact. We then assigned full damage (which reduces tensile and shear stresses to zero) to SPH particles in the contacts between the components; the remaining volume is void space. The internal spherical components have a power-law distribution of sizes simulating fragments of a pre-shattered parent object. First-look analysis of the rubble-pile results indicate some general similarities to the simulations with the monolithic targets (e.g., similar trends in the number of small, gravitationally bound satellite systems as a function of impact conditions) and some significant differences (e.g., size of largest remnants and smaller debris affecting size frequency distributions of resulting families). We will report details of a more thorough analysis and the implications for collisional models of the main asteroid belt. This work is supported by the National Science Foundation, grant number AST0407045.

Thin films structural properties: results of the full-atomistic supercomputer simulation

NASA Astrophysics Data System (ADS)

Grigoriev, F. V.; Sulimov, V. B.; Tikhonravov, A. V.

2017-12-01

The previously developed full-atomistic approach to the thin film growth simulation is applied for the investigation of the dependence of silicon dioxide films properties on deposition conditions. It is shown that the surface roughness and porosity are essentially reduced with the growth of energy of deposited silicon atoms. The growth of energy from 0.1 eV to 10 eV results in the increase of the film density for 0.2 - 0.4 g/cm3 and of the refractive index for 0.04-0.08. The compressive stress in films structures is observed for all deposition conditions. Absolute values of the stress tensor components increase with the growth of e energy of deposited atoms. The increase of the substrate temperature results in smoothing of the density profiles of the deposited films.

Computer Simulation Results for the Two-Point Probability Function of Composite Media

NASA Astrophysics Data System (ADS)

Smith, P.; Torquato, S.

1988-05-01

Computer simulation results are reported for the two-point matrix probability function S2 of two-phase random media composed of disks distributed with an arbitrary degree of impenetrability λ. The novel technique employed to sample S2( r) (which gives the probability of finding the endpoints of a line segment of length r in the matrix) is very accurate and has a fast execution time. Results for the limiting cases λ = 0 (fully penetrable disks) and λ = 1 (hard disks), respectively, compare very favorably with theoretical predictions made by Torquato and Beasley and by Torquato and Lado. Results are also reported for several values of λ. that lie between these two extremes: cases which heretofore have not been examined.

Southern Arizona hydroclimate over the last 3000 years: a comparison of speleothem elemental data and climate model simulations

NASA Astrophysics Data System (ADS)

King, J.; Harrington, M. D.; Cole, J. E.; Drysdale, R.; Woodhead, J. D.; Fasullo, J.; Stevenson, S.; Otto-Bliesner, B. L.; Overpeck, J. T.; Edwards, R. L.; Henderson, G. M.

2017-12-01

Understanding long-term hydroclimate is particularly important in semiarid regions where prolonged droughts may be exacerbated by a warming climate. In many regions, speleothem trace elements correlate with regional wet and dry climate signals. In the drought-prone Southwestern US (SW), wet and dry episodes are strongly influenced by seasonal changes in atmospheric circulation and teleconnections to remote forcing. Here, we address the need for seasonal moisture reconstructions using paleoclimate and climate model approaches. First, we present a high-resolution (sub-annual) record of speleothem trace elements spanning the last 3000 years from Fort Huachuca Cave, AZ, to investigate the variability of regional seasonal precipitation and sustained regional droughts. In a principal component (PC) analysis of the speleothem, trace elements associated with wet (Sr, Ba) and dry (P, Y, Zn) episodes load strongly and inversely, and the associated PC signals correlate with local gridded precipitation data over the last 50 years (R > 0.6, p < 0.1). These results suggest that the elemental signals provide a seasonal moisture record for Southern Arizona. We use the record to examine the frequency and timing of extreme droughts in the region and compare the speleothem record's frequency domain characteristics with other regional moisture records and with climate model output. The speleothem record demonstrates strong low-frequency variability with pronounced multi-decadal dry periods, a feature notably lacking in drought metrics from simulations of the last millennium. We also examine the seasonal SW precipitation response to modes of climate variability and external forcings, including volcanic eruptions, in both the speleothem record and the Community Earth System Model's Last Millennium Ensemble (CESM-LME). Notably, ENSO and volcanic forcing have a discernable effect on SW seasonal precipitation in model simulations, particularly when the two processes combine to shift the

Conversion of NIMROD simulation results for graphical analysis using VisIt

DOE Office of Scientific and Technical Information (OSTI.GOV)

Romero-Talamas, C A

Software routines developed to prepare NIMROD [C. R. Sovinec et al., J. Comp. Phys. 195, 355 (2004)] results for three-dimensional visualization from simulations of the Sustained Spheromak Physics Experiment (SSPX ) [E. B. Hooper et al., Nucl. Fusion 39, 863 (1999)] are presented here. The visualization is done by first converting the NIMROD output to a format known as legacy VTK and then loading it to VisIt, a graphical analysis tool that includes three-dimensional rendering and various mathematical operations for large data sets. Sample images obtained from the processing of NIMROD data with VisIt are included.

Using a High-Fidelity Patient Simulator with First-Year Medical Students to Facilitate Learning of Cardiovascular Function Curves

ERIC Educational Resources Information Center

Harris, David M.; Ryan, Kathleen; Rabuck, Cynthia

2012-01-01

Students are relying on technology for learning more than ever, and educators need to adapt to facilitate student learning. High-fidelity patient simulators (HFPS) are usually reserved for the clinical years of medical education and are geared to improve clinical decision skills, teamwork, and patient safety. Finding ways to incorporate HFPS into…

Molecular Simulation Results on Charged Carbon Nanotube Forest-Based Supercapacitors.

PubMed

Muralidharan, Ajay; Pratt, Lawrence R; Hoffman, Gary G; Chaudhari, Mangesh I; Rempe, Susan B

2018-06-22

Electrochemical double-layer capacitances of charged carbon nanotube (CNT) forests with tetraethyl ammonium tetrafluoro borate electrolyte in propylene carbonate are studied on the basis of molecular dynamics simulation. Direct molecular simulation of the filling of pore spaces of the forest is feasible even with realistic, small CNT spacings. The numerical solution of the Poisson equation based on the extracted average charge densities then yields a regular experimental dependence on the width of the pore spaces, in contrast to the anomalous pattern observed in experiments on other carbon materials and also in simulations on planar slot-like pores. The capacitances obtained have realistic magnitudes but are insensitive to electric potential differences between the electrodes in this model. This agrees with previous calculations on CNT forest supercapacitors, but not with experiments which have suggested electrochemical doping for these systems. Those phenomena remain for further theory/modeling work. © 2018 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

THE TAOS PROJECT: RESULTS FROM SEVEN YEARS OF SURVEY DATA

DOE Office of Scientific and Technical Information (OSTI.GOV)

Zhang, Z.-W.; Lehner, M. J.; Wang, J.-H.

2013-07-01

The Taiwanese-American Occultation Survey (TAOS) aims to detect serendipitous occultations of stars by small ({approx}1 km diameter) objects in the Kuiper Belt and beyond. Such events are very rare (<10{sup -3} events per star per year) and short in duration ({approx}200 ms), so many stars must be monitored at a high readout cadence. TAOS monitors typically {approx}500 stars simultaneously at a 5 Hz readout cadence with four telescopes located at Lulin Observatory in central Taiwan. In this paper, we report the results of the search for small Kuiper Belt objects (KBOs) in seven years of data. No occultation events weremore » found, resulting in a 95% c.l. upper limit on the slope of the faint end of the KBO size distribution of q = 3.34-3.82, depending on the surface density at the break in the size distribution at a diameter of about 90 km.« less

Simulation results for a finite element-based cumulative reconstructor

NASA Astrophysics Data System (ADS)

Wagner, Roland; Neubauer, Andreas; Ramlau, Ronny

2017-10-01

Modern ground-based telescopes rely on adaptive optics (AO) systems for the compensation of image degradation caused by atmospheric turbulences. Within an AO system, measurements of incoming light from guide stars are used to adjust deformable mirror(s) in real time that correct for atmospheric distortions. The incoming wavefront has to be derived from sensor measurements, and this intermediate result is then translated into the shape(s) of the deformable mirror(s). Rapid changes of the atmosphere lead to the need for fast wavefront reconstruction algorithms. We review a fast matrix-free algorithm that was developed by Neubauer to reconstruct the incoming wavefront from Shack-Hartmann measurements based on a finite element discretization of the telescope aperture. The method is enhanced by a domain decomposition ansatz. We show that this algorithm reaches the quality of standard approaches in end-to-end simulation while at the same time maintaining the speed of recently introduced solvers with linear order speed.

Simulation of General Physics laboratory exercise

NASA Astrophysics Data System (ADS)

Aceituno, P.; Hernández-Aceituno, J.; Hernández-Cabrera, A.

2015-01-01

Laboratory exercises are an important part of general Physics teaching, both during the last years of high school and the first year of college education. Due to the need to acquire enough laboratory equipment for all the students, and the widespread access to computers rooms in teaching, we propose the development of computer simulated laboratory exercises. A representative exercise in general Physics is the calculation of the gravity acceleration value, through the free fall motion of a metal ball. Using a model of the real exercise, we have developed an interactive system which allows students to alter the starting height of the ball to obtain different fall times. The simulation was programmed in ActionScript 3, so that it can be freely executed in any operative system; to ensure the accuracy of the calculations, all the input parameters of the simulations were modelled using digital measurement units, and to allow a statistical management of the resulting data, measurement errors are simulated through limited randomization.

[Experimental study on the retentive force of cobalt-chromium alloy, pure titanium and vitallium cast clasps in the simulated 3-year clinical use].

PubMed

Yan, Hai-xin; Zhao, Yan-bo; Qin, Li-mei; Zhu, Hai-ting; Wu, Lin

2015-12-01

To investigate the changes of retentive force of cobalt-chromium alloy, pure titanium and vitallium cast clasps in the simulated 3-year clinical use. Fifteen metal abutment crowns made of No.QT800-2 nodular cast iron were used in the test. Five clasps from each of the following alloys: cobalt-chromium alloy, pure titanium and vitallium were fabricated. The undercut depth was 0.25 mm. A masticatory simulator was used to cycle the clasp on and off the metal abutment crown 5000 times, simulating 3-year clinical use. Retentive force was measured 11 times during this process. SPSS13.0 software package was used to analyze the results. Casting defects were observed using X-ray non destructive testing (X-ray NDT) before cyclic test. Surface characteristics were qualitatively evaluated using scanning electron microscope (SEM) before and after cyclic test. The results indicated that there were significant differences (P=0.000) in the retentive force of the 3 groups before and after the cyclic test. The highest retentive force was recorded in the vitallium clasps, and the lowest retentive force was measured in the pure titanium clasps. The results of X-ray NDT depicted the typical casting defect seen at the end of the connector. SEM examination revealed that no evidence of pores and cracks in the inner surfaces of the 3 groups was found before cyclic test. Wear was evident in the inner surfaces of the 3 groups but none of the clasps exhibited any evidence of cracks after cyclic test through SEM examination. In this in vitro test, vitallium clasps show the best retentive force in the 3 groups before and after 5000 cycles at 0.25 mm undercut depth. Cobalt-chromium alloy and vitallium clasps can maintain ideal retentive force at 0.25mm undercut depth in the long-term use. Wear may be one of the reasons for the loss of retentive force of clasps in the cyclic test.

Natrelle round silicone breast implants: Core Study results at 10 years.

PubMed

Spear, Scott L; Murphy, Diane K

2014-06-01

Allergan's Natrelle round silicone-filled breast implants were approved by the U.S. Food and Drug Administration in 2006 based on interim results from the Core Study; final 10-year study results are now available. Seven hundred fifteen subjects were implanted with smooth and Biocell textured Natrelle round silicone implants and attended clinic visits at 0 to 4 weeks, 6 months, 1 year, and annually through 10 years. Approximately one-third of subjects underwent magnetic resonance imaging at years 1, 3, 5, 7, and 9 to assess rupture. Complication rates showed modest increases over the previously published 6-year rates. The Kaplan-Meier capsular contracture rate was 18.9 percent for augmentation, 28.7 percent for revision-augmentation, and 24.6 percent for reconstruction. Among augmentation subjects, capsular contracture was significantly lower (p = 0.023) for submuscular (15.7 percent) versus subglandular (26.3 percent) placement. The overall rupture rate in the magnetic resonance imaging cohort was 13.0 percent for subjects and 7.7 percent for implants. By the end of the study, 81.8 percent of augmentation subjects still had an original implant in place. Using a five-point scale, 94.2 percent of augmentation, 83.8 percent of revision-augmentation, and 90.7 percent of reconstruction subjects reported being satisfied or definitely satisfied with their implants. Significant improvement over baseline was also seen in overall breast satisfaction and satisfaction with breast size, shape, feel, and how well they matched. The 10-year data from the Natrelle Core Study, which can guide surgeons and patients in decision-making, demonstrate safety and high levels of patient satisfaction. Therapeutic, III.

Four-year to Eight-year Results of Vagotomy and Simple Drainage for Benign Lesser Curve Gastric Ulcer

PubMed Central

Burge, H.; Gill, A. Morton; Maclean, C.; Stedeford, R.

1970-01-01

The results of vagotomy and simple drainage for recurrent benign lesser curve gastric ulcer are recorded. Seventy-two consecutive cases were treated from 1962 to 1965. The follow-up is therefore from five to eight years. In only two cases did the ulcer fail to heal and remain healed. Four years after operation both these had persistent ulceration and persistent gastric retention. Both have apparently been cured by gastrojejunostomy done to improve gastric drainage. ImagesFIG. 1FIG. 2FIG. 3 PMID:5451588

Impacts of building geometry modeling methods on the simulation results of urban building energy models

DOE Office of Scientific and Technical Information (OSTI.GOV)

Chen, Yixing; Hong, Tianzhen

We present that urban-scale building energy modeling (UBEM)—using building modeling to understand how a group of buildings will perform together—is attracting increasing attention in the energy modeling field. Unlike modeling a single building, which will use detailed information, UBEM generally uses existing building stock data consisting of high-level building information. This study evaluated the impacts of three zoning methods and the use of floor multipliers on the simulated energy use of 940 office and retail buildings in three climate zones using City Building Energy Saver. The first zoning method, OneZone, creates one thermal zone per floor using the target building'smore » footprint. The second zoning method, AutoZone, splits the building's footprint into perimeter and core zones. A novel, pixel-based automatic zoning algorithm is developed for the AutoZone method. The third zoning method, Prototype, uses the U.S. Department of Energy's reference building prototype shapes. Results show that simulated source energy use of buildings with the floor multiplier are marginally higher by up to 2.6% than those modeling each floor explicitly, which take two to three times longer to run. Compared with the AutoZone method, the OneZone method results in decreased thermal loads and less equipment capacities: 15.2% smaller fan capacity, 11.1% smaller cooling capacity, 11.0% smaller heating capacity, 16.9% less heating loads, and 7.5% less cooling loads. Source energy use differences range from -7.6% to 5.1%. When comparing the Prototype method with the AutoZone method, source energy use differences range from -12.1% to 19.0%, and larger ranges of differences are found for the thermal loads and equipment capacities. This study demonstrated that zoning methods have a significant impact on the simulated energy use of UBEM. Finally, one recommendation resulting from this study is to use the AutoZone method with floor multiplier to obtain accurate results while

Impacts of building geometry modeling methods on the simulation results of urban building energy models

DOE PAGES

Chen, Yixing; Hong, Tianzhen

2018-02-20

We present that urban-scale building energy modeling (UBEM)—using building modeling to understand how a group of buildings will perform together—is attracting increasing attention in the energy modeling field. Unlike modeling a single building, which will use detailed information, UBEM generally uses existing building stock data consisting of high-level building information. This study evaluated the impacts of three zoning methods and the use of floor multipliers on the simulated energy use of 940 office and retail buildings in three climate zones using City Building Energy Saver. The first zoning method, OneZone, creates one thermal zone per floor using the target building'smore » footprint. The second zoning method, AutoZone, splits the building's footprint into perimeter and core zones. A novel, pixel-based automatic zoning algorithm is developed for the AutoZone method. The third zoning method, Prototype, uses the U.S. Department of Energy's reference building prototype shapes. Results show that simulated source energy use of buildings with the floor multiplier are marginally higher by up to 2.6% than those modeling each floor explicitly, which take two to three times longer to run. Compared with the AutoZone method, the OneZone method results in decreased thermal loads and less equipment capacities: 15.2% smaller fan capacity, 11.1% smaller cooling capacity, 11.0% smaller heating capacity, 16.9% less heating loads, and 7.5% less cooling loads. Source energy use differences range from -7.6% to 5.1%. When comparing the Prototype method with the AutoZone method, source energy use differences range from -12.1% to 19.0%, and larger ranges of differences are found for the thermal loads and equipment capacities. This study demonstrated that zoning methods have a significant impact on the simulated energy use of UBEM. Finally, one recommendation resulting from this study is to use the AutoZone method with floor multiplier to obtain accurate results while

Longitudinal design considerations to optimize power to detect variances and covariances among rates of change: Simulation results based on actual longitudinal studies

PubMed Central

Rast, Philippe; Hofer, Scott M.

2014-01-01

We investigated the power to detect variances and covariances in rates of change in the context of existing longitudinal studies using linear bivariate growth curve models. Power was estimated by means of Monte Carlo simulations. Our findings show that typical longitudinal study designs have substantial power to detect both variances and covariances among rates of change in a variety of cognitive, physical functioning, and mental health outcomes. We performed simulations to investigate the interplay among number and spacing of occasions, total duration of the study, effect size, and error variance on power and required sample size. The relation between growth rate reliability (GRR) and effect size to the sample size required to detect power ≥ .80 was non-linear, with rapidly decreasing sample sizes needed as GRR increases. The results presented here stand in contrast to previous simulation results and recommendations (Hertzog, Lindenberger, Ghisletta, & von Oertzen, 2006; Hertzog, von Oertzen, Ghisletta, & Lindenberger, 2008; von Oertzen, Ghisletta, & Lindenberger, 2010), which are limited due to confounds between study length and number of waves, error variance with GCR, and parameter values which are largely out of bounds of actual study values. Power to detect change is generally low in the early phases (i.e. first years) of longitudinal studies but can substantially increase if the design is optimized. We recommend additional assessments, including embedded intensive measurement designs, to improve power in the early phases of long-term longitudinal studies. PMID:24219544

JASMINE simulator

NASA Astrophysics Data System (ADS)

Yamada, Yoshiyuki; Gouda, Naoteru; Yano, Taihei; Kobayashi, Yukiyasu; Tsujimoto, Takuji; Suganuma, Masahiro; Niwa, Yoshito; Sako, Nobutada; Hatsutori, Yoichi; Tanaka, Takashi

2006-06-01

We explain simulation tools in JASMINE project (JASMINE simulator). The JASMINE project stands at the stage where its basic design will be determined in a few years. Then it is very important to simulate the data stream generated by astrometric fields at JASMINE in order to support investigations into error budgets, sampling strategy, data compression, data analysis, scientific performances, etc. Of course, component simulations are needed, but total simulations which include all components from observation target to satellite system are also very important. We find that new software technologies, such as Object Oriented(OO) methodologies are ideal tools for the simulation system of JASMINE(the JASMINE simulator). In this article, we explain the framework of the JASMINE simulator.

Simulation Needs and Priorities of the Fermilab Intensity Frontier

DOE Office of Scientific and Technical Information (OSTI.GOV)

Elvira, V. D.; Genser, K. L.; Hatcher, R.

2015-06-11

Over a two-year period, the Physics and Detector Simulations (PDS) group of the Fermilab Scientific Computing Division (SCD), collected information from Fermilab Intensity Frontier experiments on their simulation needs and concerns. The process and results of these activities are documented here.

Nutrient transports in the Baltic Sea - results from a 30-year physical-biogeochemical reanalysis

NASA Astrophysics Data System (ADS)

Liu, Ye; Meier, H. E. Markus; Eilola, Kari

2017-04-01

Long-term oxygen and nutrient transports in the Baltic Sea are reconstructed using the Swedish Coastal and Ocean Biogeochemical model (SCOBI) coupled to the Rossby Centre Ocean model (RCO). Two simulations with and without data assimilation covering the period 1970-1999 are carried out. Here, the weakly coupled scheme with the Ensemble Optimal Interpolation (EnOI) method is adopted to assimilate observed profiles in the reanalysis system. The reanalysis shows considerable improvement in the simulation of both oxygen and nutrient concentrations relative to the free run. Further, the results suggest that the assimilation of biogeochemical observations has a significant effect on the simulation of the oxygen-dependent dynamics of biogeochemical cycles. From the reanalysis, nutrient transports between sub-basins, between the coastal zone and the open sea, and across latitudinal and longitudinal cross sections are calculated. Further, the spatial distributions of regions with nutrient import or export are examined. Our results emphasize the important role of the Baltic proper for the entire Baltic Sea, with large net transport (export minus import) of nutrients from the Baltic proper into the surrounding sub-basins (except the net phosphorus import from the Gulf of Riga and the net nitrogen import from the Gulf of Riga and Danish Straits). In agreement with previous studies, we found that the Bothnian Sea imports large amounts of phosphorus from the Baltic proper that are retained in this sub-basin. For the calculation of sub-basin budgets, the location of the lateral borders of the sub-basins is crucial, because net transports may change sign with the location of the border. Although the overall transport patterns resemble the results of previous studies, our calculated estimates differ in detail considerably.

Combining Genome-Wide Information with a Functional Structural Plant Model to Simulate 1-Year-Old Apple Tree Architecture.

PubMed

Migault, Vincent; Pallas, Benoît; Costes, Evelyne

2016-01-01

In crops, optimizing target traits in breeding programs can be fostered by selecting appropriate combinations of architectural traits which determine light interception and carbon acquisition. In apple tree, architectural traits were observed to be under genetic control. However, architectural traits also result from many organogenetic and morphological processes interacting with the environment. The present study aimed at combining a FSPM built for apple tree, MAppleT, with genetic determinisms of architectural traits, previously described in a bi-parental population. We focused on parameters related to organogenesis (phyllochron and immediate branching) and morphogenesis processes (internode length and leaf area) during the first year of tree growth. Two independent datasets collected in 2004 and 2007 on 116 genotypes, issued from a 'Starkrimson' × 'Granny Smith' cross, were used. The phyllochron was estimated as a function of thermal time and sylleptic branching was modeled subsequently depending on phyllochron. From a genetic map built with SNPs, marker effects were estimated on four MAppleT parameters with rrBLUP, using 2007 data. These effects were then considered in MAppleT to simulate tree development in the two climatic conditions. The genome wide prediction model gave consistent estimations of parameter values with correlation coefficients between observed values and estimated values from SNP markers ranging from 0.79 to 0.96. However, the accuracy of the prediction model following cross validation schemas was lower. Three integrative traits (the number of leaves, trunk length, and number of sylleptic laterals) were considered for validating MAppleT simulations. In 2007 climatic conditions, simulated values were close to observations, highlighting the correct simulation of genetic variability. However, in 2004 conditions which were not used for model calibration, the simulations differed from observations. This study demonstrates the possibility of

A-Level Results in Comprehensive Schools: The COMBSE Project, Year 1.

ERIC Educational Resources Information Center

Fitz-Gibbon, Carol T.

1985-01-01

Results of the first year of the ongoing Confidential, Measurement-Based, Self-Evaluation Project that examines variables related to A-level English and Mathematics achievement in 10 comprehensive schools in the United Kingdom are presented. A-level results were found to be strongly predicted by teacher assessments and by prior O-level achievement…

Ion cyclotron instability at Io: Hybrid simulation results compared to in situ observations

NASA Astrophysics Data System (ADS)

Šebek, Ondřej; Trávníček, Pavel M.; Walker, Raymond J.; Hellinger, Petr

2016-08-01

We present analysis of global three-dimensional hybrid simulations of Io's interaction with Jovian magnetospheric plasma. We apply a single-species model with simplified neutral-plasma chemistry and downscale Io in order to resolve the ion kinetic scales. We consider charge exchange, electron impact ionization, and photoionization by using variable rates of these processes to investigate their impact. Our results are in a good qualitative agreement with the in situ magnetic field measurements for five Galileo flybys around Io. The hybrid model describes ion kinetics self-consistently. This allows us to assess the distribution of temperature anisotropies around Io and thereby determine the possible triggering mechanism for waves observed near Io. We compare simulated dynamic spectra of magnetic fluctuations with in situ observations made by Galileo. Our results are consistent with both the spatial distribution and local amplitude of magnetic fluctuations found in the observations. Cyclotron waves, triggered probably by the growth of ion cyclotron instability, are observed mainly downstream of Io and on the flanks in regions farther from Io where the ion pickup rate is relatively low. Growth of the ion cyclotron instability is governed mainly by the charge exchange rate.

Meteorologically Driven Simulations of Dengue Epidemics in San Juan, PR

PubMed Central

Morin, Cory W.; Monaghan, Andrew J.; Hayden, Mary H.; Barrera, Roberto; Ernst, Kacey

2015-01-01

Meteorological factors influence dengue virus ecology by modulating vector mosquito population dynamics, viral replication, and transmission. Dynamic modeling techniques can be used to examine how interactions among meteorological variables, vectors and the dengue virus influence transmission. We developed a dengue fever simulation model by coupling a dynamic simulation model for Aedes aegypti, the primary mosquito vector for dengue, with a basic epidemiological Susceptible-Exposed-Infectious-Recovered (SEIR) model. Employing a Monte Carlo approach, we simulated dengue transmission during the period of 2010–2013 in San Juan, PR, where dengue fever is endemic. The results of 9600 simulations using varied model parameters were evaluated by statistical comparison (r2) with surveillance data of dengue cases reported to the Centers for Disease Control and Prevention. To identify the most influential parameters associated with dengue virus transmission for each period the top 1% of best-fit model simulations were retained and compared. Using the top simulations, dengue cases were simulated well for 2010 (r2 = 0.90, p = 0.03), 2011 (r2 = 0.83, p = 0.05), and 2012 (r2 = 0.94, p = 0.01); however, simulations were weaker for 2013 (r2 = 0.25, p = 0.25) and the entire four-year period (r2 = 0.44, p = 0.002). Analysis of parameter values from retained simulations revealed that rain dependent container habitats were more prevalent in best-fitting simulations during the wetter 2010 and 2011 years, while human managed (i.e. manually filled) container habitats were more prevalent in best-fitting simulations during the drier 2012 and 2013 years. The simulations further indicate that rainfall strongly modulates the timing of dengue (e.g., epidemics occurred earlier during rainy years) while temperature modulates the annual number of dengue fever cases. Our results suggest that meteorological factors have a time-variable influence on dengue transmission relative to other important

Visualization and simulation techniques for surgical simulators using actual patient's data.

PubMed

Radetzky, Arne; Nürnberger, Andreas

2002-11-01

Because of the increasing complexity of surgical interventions research in surgical simulation became more and more important over the last years. However, the simulation of tissue deformation is still a challenging problem, mainly due to the short response times that are required for real-time interaction. The demands to hard and software are even larger if not only the modeled human anatomy is used but the anatomy of actual patients. This is required if the surgical simulator should be used as training medium for expert surgeons rather than students. In this article, suitable visualization and simulation methods for surgical simulation utilizing actual patient's datasets are described. Therefore, the advantages and disadvantages of direct and indirect volume rendering for the visualization are discussed and a neuro-fuzzy system is described, which can be used for the simulation of interactive tissue deformations. The neuro-fuzzy system makes it possible to define the deformation behavior based on a linguistic description of the tissue characteristics or to learn the dynamics by using measured data of real tissue. Furthermore, a simulator for minimally-invasive neurosurgical interventions is presented that utilizes the described visualization and simulation methods. The structure of the simulator is described in detail and the results of a system evaluation by an experienced neurosurgeon--a quantitative comparison between different methods of virtual endoscopy as well as a comparison between real brain images and virtual endoscopies--are given. The evaluation proved that the simulator provides a higher realism of the visualization and simulation then other currently available simulators. Copyright 2002 Elsevier Science B.V.

Five Years of Cenosumab Exposure in Women With Postmenopausal Osteoporosis: Results From the First Two Years of the FREEDOM Extension

PubMed Central

Papapoulos, Socrates; Chapurlat, Roland; Libanati, Cesar; Brandi, Maria Luisa; Brown, Jacques P; Czerwiński, Edward; Krieg, Marc-Antoine; Man, Zulema; Mellström, Dan; Radominski, Sebastião C; Reginster, Jean-Yves; Resch, Heinrich; Ivorra, José A Román; Roux, Christian; Vittinghoff, Eric; Austin, Matthew; Daizadeh, Nadia; Bradley, Michelle N; Grauer, Andreas; Cummings, Steven R; Bone, Henry G

2012-01-01

The 3-year FREEDOM trial assessed the efficacy and safety of 60 mg denosumab every 6 months for the treatment of postmenopausal women with osteoporosis. Participants who completed the FREEDOM trial were eligible to enter an extension to continue the evaluation of denosumab efficacy and safety for up to 10 years. For the extension results presented here, women from the FREEDOM denosumab group had 2 more years of denosumab treatment (long-term group) and those from the FREEDOM placebo group had 2 years of denosumab exposure (cross-over group). We report results for bone turnover markers (BTMs), bone mineral density (BMD), fracture rates, and safety. A total of 4550 women enrolled in the extension (2343 long-term; 2207 cross-over). Reductions in BTMs were maintained (long-term group) or occurred rapidly (cross-over group) following denosumab administration. In the long-term group, lumbar spine and total hip BMD increased further, resulting in 5-year gains of 13.7% and 7.0%, respectively. In the cross-over group, BMD increased at the lumbar spine (7.7%) and total hip (4.0%) during the 2-year denosumab treatment. Yearly fracture incidences for both groups were below rates observed in the FREEDOM placebo group and below rates projected for a “virtual untreated twin” cohort. Adverse events did not increase with long-term denosumab administration. Two adverse events in the cross-over group were adjudicated as consistent with osteonecrosis of the jaw. Five-year denosumab treatment of women with postmenopausal osteoporosis maintained BTM reduction and increased BMD, and was associated with low fracture rates and a favorable risk/benefit profile. © 2012 American Society for Bone and Mineral Research PMID:22113951

Simulating a patient's fall as a means to improve routine communication: Joint training for nursing and fifth-year medical students.

PubMed

Flentje, Markus; Müßel, Thomas; Henzel, Bettina; Jantzen, Jan-Peter

2016-01-01

Physicians and nursing staff interact as a team on a daily basis in hospital settings. However, both educational paths offer few opportunities to establish contact with the other professional group. Neither professional group can practice its later role with the other group in a "safe" learning environment. Routine interprofessional collaboration is described as being in need of great improvement and carries with it the potential for conflict. To improve interprofessional communication and task management, a simulation-based emergency training session for nursing students and fifth-year medical students was developed at the KRH Klinikum Nordstadt in Hanover, Germany. As a pilot project, the course was held twice in the form of a one-day session with ten nursing and four medical students. Using the example of a patient's fall, course participants were able to observe and actively treat multiple simulated patients. Following each simulation the trainer conducted a comprehensive debriefing. The course was then evaluated using a questionnaire. The evaluation of the team training showed a high level of acceptance among the two participating professional groups. On a scale of 1 (hardly applicable) to 5 (strongly applicable), the course was given a 4 by both professional groups for its relevance to daily work. In the open-ended written responses praise was specifically given for the opportunity to learn how to switch perspectives as a result of the simulation exercises. A common emergency on the hospital ward offers a good opportunity to establish and practice interprofessional team skills. With the knowledge gained about communication and the ability to change viewpoints, participants are able to improve their team skills. Participants demonstrated a high degree of acceptance for the training program.

Quiet Clean Short-haul Experimental Engine (QCSEE) over-the-wing engine and control simulation results

NASA Technical Reports Server (NTRS)

1978-01-01

A hybrid-computer simulation of the over the wing turbofan engine was constructed to develop the dynamic design of the control. This engine and control system includes a full authority digital electronic control using compressor stator reset to achieve fast thrust response and a modified Kalman filter to correct for sensor failures. Fast thrust response for powered-lift operations and accurate, fast responding, steady state control of the engine is provided. Simulation results for throttle bursts from 62 to 100 percent takeoff thrust predict that the engine will accelerate from 62 to 95 percent takeoff thrust in one second.

Simulated building energy demand biases resulting from the use of representative weather stations

DOE Office of Scientific and Technical Information (OSTI.GOV)

Burleyson, Casey D.; Voisin, Nathalie; Taylor, Z. Todd

Numerical building models are typically forced with weather data from a limited number of “representative cities” or weather stations representing different climate regions. The use of representative weather stations reduces computational costs, but often fails to capture spatial heterogeneity in weather that may be important for simulations aimed at understanding how building stocks respond to a changing climate. We quantify the potential reduction in bias from using an increasing number of weather stations over the western U.S. The approach is based on deriving temperature and load time series using incrementally more weather stations, ranging from 8 to roughly 150, tomore » capture weather across different seasons. Using 8 stations, one from each climate zone, across the western U.S. results in an average absolute summertime temperature bias of 7.2°F with respect to a spatially-resolved gridded dataset. The mean absolute bias drops to 2.8°F using all available weather stations. Temperature biases of this magnitude could translate to absolute summertime mean simulated load biases as high as 13.8%, a significant error for capacity expansion planners who may use these types of simulations. Increasing the size of the domain over which biases are calculated reduces their magnitude as positive and negative biases may cancel out. Using 8 representative weather stations can lead to a 20-40% overestimation of peak building loads during both summer and winter. Using weather stations close to population centers reduces both mean and peak load biases. This approach could be used by others designing aggregate building simulations to understand the sensitivity to their choice of weather stations used to drive the models.« less

Results and Lessons Learned from Performance Testing of Humans in Spacesuits in Simulated Reduced Gravity

NASA Technical Reports Server (NTRS)

Chappell, Steven P.; Norcross, Jason R.; Gernhardt, Michael L.

2009-01-01

NASA's Constellation Program has plans to return to the Moon within the next 10 years. Although reaching the Moon during the Apollo Program was a remarkable human engineering achievement, fewer than 20 extravehicular activities (EVAs) were performed. Current projections indicate that the next lunar exploration program will require thousands of EVAs, which will require spacesuits that are better optimized for human performance. Limited mobility and dexterity, and the position of the center of gravity (CG) are a few of many features of the Apollo suit that required significant crew compensation to accomplish the objectives. Development of a new EVA suit system will ideally result in performance close to or better than that in shirtsleeves at 1 G, i.e., in "a suit that is a pleasure to work in, one that you would want to go out and explore in on your day off." Unlike the Shuttle program, in which only a fraction of the crew perform EVA, the Constellation program will require that all crewmembers be able to perform EVA. As a result, suits must be built to accommodate and optimize performance for a larger range of crew anthropometry, strength, and endurance. To address these concerns, NASA has begun a series of tests to better understand the factors affecting human performance and how to utilize various lunar gravity simulation environments available for testing.

50 years of computer simulation of the human thermoregulatory system.

PubMed

Hensley, Daniel W; Mark, Andrew E; Abella, Jayvee R; Netscher, George M; Wissler, Eugene H; Diller, Kenneth R

2013-02-01

This paper presents an updated and augmented version of the Wissler human thermoregulation model that has been developed continuously over the past 50 years. The existing Fortran code is translated into C with extensive embedded commentary. A graphical user interface (GUI) has been developed in Python to facilitate convenient user designation of input and output variables and formatting of data presentation. Use of the code with the GUI is described and demonstrated. New physiological elements were added to the model to represent the hands and feet, including the unique vascular structures adapted for heat transfer associated with glabrous skin. The heat transfer function and efficacy of glabrous skin is unique within the entire body based on the capacity for a very high rate of blood perfusion and the novel capability for dynamic regulation of blood flow. The model was applied to quantify the absolute and relative contributions of glabrous skin flow to thermoregulation for varying levels of blood perfusion. The model also was used to demonstrate how the unique features of glabrous skin blood flow may be recruited to implement thermal therapeutic procedures. We have developed proprietary methods to manipulate the control of glabrous skin blood flow in conjunction with therapeutic devices and simulated the effect of these methods with the model.

Features of the accretion in the EX Hydrae system: Results of numerical simulation

NASA Astrophysics Data System (ADS)

Isakova, P. B.; Zhilkin, A. G.; Bisikalo, D. V.; Semena, A. N.; Revnivtsev, M. G.

2017-07-01

A two-dimensional numerical model in the axisymmetric approximation that describes the flow structure in the magnetosphere of the white dwarf in the EX Hya system has been developed. Results of simulations show that the accretion in EX Hya proceeds via accretion columns, which are not closed and have curtain-like shapes. The thickness of the accretion curtains depends only weakly on the thickness of the accretion disk. This thickness developed in the simulations does not agree with observations. It is concluded that the main reason for the formation of thick accretion curtains in the model is the assumption that the magnetic field penetrates fully into the plasma of the disk. An analysis based on simple estimates shows that a diamagnetic disk that fully or partially shields the magnetic field of the star may be a more attractive explanation for the observed features of the accretion in EX Hya.

The effects of bed rest on crew performance during simulated shuttle reentry. Volume 1: Study overview and physiological results

NASA Technical Reports Server (NTRS)

Chambers, A.; Vykukal, H. C.

1974-01-01

A centrifuge study was carried out to measure physiological stress and control task performance during simulated space shuttle orbiter reentry. Jet pilots were tested with, and without, anti-g-suit protection. The pilots were exposed to simulated space shuttle reentry acceleration profiles before, and after, ten days of complete bed rest, which produced physiological deconditioning similar to that resulting from prolonged exposure to orbital zero g. Pilot performance in selected control tasks was determined during simulated reentry, and before and after each simulation. Physiological stress during reentry was determined by monitoring heart rate, blood pressure, and respiration rate. Study results indicate: (1) heart rate increased during the simulated reentry when no g protection was given, and remained at or below pre-bed rest values when g-suits were used; (2) pilots preferred the use of g-suits to muscular contraction for control of vision tunneling and grayout during reentry; (3) prolonged bed rest did not alter blood pressure or respiration rate during reentry, but the peak reentry acceleration level did; and (4) pilot performance was not affected by prolonged bed rest or simulated reentry.

Relative solvation free energies calculated using an ab initio QM/MM-based free energy perturbation method: dependence of results on simulation length.

PubMed

Reddy, M Rami; Erion, Mark D

2009-12-01

Molecular dynamics (MD) simulations in conjunction with thermodynamic perturbation approach was used to calculate relative solvation free energies of five pairs of small molecules, namely; (1) methanol to ethane, (2) acetone to acetamide, (3) phenol to benzene, (4) 1,1,1 trichloroethane to ethane, and (5) phenylalanine to isoleucine. Two studies were performed to evaluate the dependence of the convergence of these calculations on MD simulation length and starting configuration. In the first study, each transformation started from the same well-equilibrated configuration and the simulation length was varied from 230 to 2,540 ps. The results indicated that for transformations involving small structural changes, a simulation length of 860 ps is sufficient to obtain satisfactory convergence. In contrast, transformations involving relatively large structural changes, such as phenylalanine to isoleucine, require a significantly longer simulation length (>2,540 ps) to obtain satisfactory convergence. In the second study, the transformation was completed starting from three different configurations and using in each case 860 ps of MD simulation. The results from this study suggest that performing one long simulation may be better than averaging results from three different simulations using a shorter simulation length and three different starting configurations.

Precommercial thinning in a northern conifer stand: 18-year results

Treesearch

John C. Brissette; Robert M., Jr. Frank; Timothy L. Stone; Thomas A. Skratt

1999-01-01

Four levels of precommercial thinning were applied with and without fertilization in a young, even-aged stand of northern conifers in east-central Maine. After 18 years, precommercial thinning resulted in longer and wider crowns and greater survival, growth, and yield of selected crop trees compared to untreated controls. Growth and yield were greater with uniform...

Near-peer medical student simulation training.

PubMed

Cash, Thomas; Brand, Eleanor; Wong, Emma; Richardson, Jay; Athorn, Sam; Chowdhury, Faiza

2017-06-01

There is growing concern that medical students are inadequately prepared for life as a junior doctor. A lack of confidence managing acutely unwell patients is often cited as a barrier to good clinical care. With medical schools investing heavily in simulation equipment, we set out to explore if near-peer simulation training is an effective teaching format. Medical students in their third year of study and above were invited to attend a 90-minute simulation teaching session. The sessions were designed and delivered by final-year medical students using clinical scenarios mapped to the Sheffield MBChB curriculum. Candidates were required to assess, investigate and manage an acutely unwell simulated patient. Pre- and post-simulation training Likert scale questionnaires were completed relating to self-reported confidence levels. There is growing concern that medical students are inadequately prepared for life as a junior doctor RESULTS: Questionnaires were completed by 25 students (100% response rate); 52 per cent of students had no prior simulation experience. There were statistically significant improvements in self-reported confidence levels in each of the six areas assessed (p < 0.005). Thematic analysis of free-text comments indicated that candidates enjoyed the practical format of the sessions and found the experience useful. Our results suggest that near-peer medical student simulation training benefits both teacher and learner and that this simplistic model could easily be replicated at other medical schools. As the most junior members of the team, medical students are often confined to observer status. Simulation empowers students to practise independently in a safe and protected environment. Furthermore, it may help to alleviate anxiety about starting work as a junior doctor and improve future patient care. © 2016 John Wiley & Sons Ltd and The Association for the Study of Medical Education.

New simulation and measurement results on gateable DEPFET devices

NASA Astrophysics Data System (ADS)

Bähr, Alexander; Aschauer, Stefan; Hermenau, Katrin; Herrmann, Sven; Lechner, Peter H.; Lutz, Gerhard; Majewski, Petra; Miessner, Danilo; Porro, Matteo; Richter, Rainer H.; Schaller, Gerhard; Sandow, Christian; Schnecke, Martina; Schopper, Florian; Stefanescu, Alexander; Strüder, Lothar; Treis, Johannes

2012-07-01

To improve the signal to noise level, devices for optical and x-ray astronomy use techniques to suppress background events. Well known examples are e.g. shutters or frame-store Charge Coupled Devices (CCDs). Based on the DEpleted P-channel Field Effect Transistor (DEPFET) principle a so-called Gatebale DEPFET detector can be built. Those devices combine the DEPFET principle with a fast built-in electronic shutter usable for optical and x-ray applications. The DEPFET itself is the basic cell of an active pixel sensor build on a fully depleted bulk. It combines internal amplification, readout on demand, analog storage of the signal charge and a low readout noise with full sensitivity over the whole bulk thickness. A Gatebale DEPFET has all these benefits and obviates the need for an external shutter. Two concepts of Gatebale DEPFET layouts providing a built-in shutter will be introduced. Furthermore proof of principle measurements for both concepts are presented. Using recently produced prototypes a shielding of the collection anode up to 1 • 10-4 was achieved. Predicted by simulations, an optimized geometry should result in values of 1 • 10-5 and better. With the switching electronic currently in use a timing evaluation of the shutter opening and closing resulted in rise and fall times of 100ns.

Multipacting simulation and test results of BNL 704 MHz SRF gun

DOE Office of Scientific and Technical Information (OSTI.GOV)

Xu W.; Belomestnykh, S.; Ben-Zvi, I.

The BNL 704MHz SRF gun has a grooved choke joint to support the photo-cathode. Due to the distortion of grooves at the choke joint during the BCP for the choke joint, several multipacting barriers showed up when it was tested with Nb cathode stalk at JLab. We built a setup to use the spare large grain SRF cavity to test and condition the multipacting at BNL with various power sources up to 50kW. The test is carried out in three stages: testing the cavity performance without cathode, testing the cavity with the Nb cathode stalk that was used at Jlab,more » and testing the cavity with a copper cathode stalk that is based on the design for the SRF gun. This paper summarizes the results of multipacting simulation, and presents the large grain cavity test setup and the test results.« less

Evaluation of stratospheric temperature simulation results by the global GRAPES model

NASA Astrophysics Data System (ADS)

Liu, Ningwei; Wang, Yangfeng; Ma, Xiaogang; Zhang, Yunhai

2017-12-01

Global final analysis (FNL) products and the general circulation spectral model (ECHAM) were used to evaluate the simulation of stratospheric temperature by the global assimilation and prediction system (GRAPES). Through a series of comparisons, it was shown that the temperature variations at 50 hPa simulated by GRAPES were significantly elevated in the southern hemisphere, whereas simulations by ECHAM and FNL varied little over time. The regional warming predicted by GRAPES seemed to be too distinct and uncontrolled to be reasonable. The temperature difference between GRAPES and FNL (GRAPES minus FNL) was small at the start time on the global scale. Over time, the positive values became larger in more locations, especially in parts of the southern hemisphere, where the warming predicted by GRAPES was dominant, with a maximal value larger than 24 K. To determine the reasons for the stratospheric warming, we considered the model initial conditions and ozone data to be possible factors; however, a comparison and sensitivity test indicated that the errors produced by GRAPES were not significantly related to either factor. Further research focusing on the impact of factors such as vapor, heating rate, and the temperature tendency on GRAPES simulations will be conducted.

Solar Potential Analysis and Integration of the Time-Dependent Simulation Results for Semantic 3d City Models Using Dynamizers

NASA Astrophysics Data System (ADS)

Chaturvedi, K.; Willenborg, B.; Sindram, M.; Kolbe, T. H.

2017-10-01

Semantic 3D city models play an important role in solving complex real-world problems and are being adopted by many cities around the world. A wide range of application and simulation scenarios directly benefit from the adoption of international standards such as CityGML. However, most of the simulations involve properties, whose values vary with respect to time, and the current generation semantic 3D city models do not support time-dependent properties explicitly. In this paper, the details of solar potential simulations are provided operating on the CityGML standard, assessing and estimating solar energy production for the roofs and facades of the 3D building objects in different ways. Furthermore, the paper demonstrates how the time-dependent simulation results are better-represented inline within 3D city models utilizing the so-called Dynamizer concept. This concept not only allows representing the simulation results in standardized ways, but also delivers a method to enhance static city models by such dynamic property values making the city models truly dynamic. The dynamizer concept has been implemented as an Application Domain Extension of the CityGML standard within the OGC Future City Pilot Phase 1. The results are given in this paper.

The course of growth response in released white spruce--10-year results

Treesearch

Robert M. Frank; Robert M. Frank

1973-01-01

Weekly bole measurements at 4.5 feet in height were made on individual codominant white spruce trees released on one, two, three, and four sides, and on untreated controls. Results showed that after 10 years annual circumference growth was still significantly related to the degree of release. The growth trend was established the first year but significant differences...

LANNA Tests and the Prediction of Year 10 English and Mathematics Results

ERIC Educational Resources Information Center

Hemmings, Brian; Kay, Russell

2009-01-01

There is a dearth of published information about the Literacy and Numeracy National Assessment (LANNA). This study was designed to explore the relationships among LANNA test scores at Year 7 and, in addition, to examine the predictive capacity of these scores in relation to Year 10 School Certificate English and Mathematics results. As a way of…

FIELD SIMULATION OF WET AND DRY YEARS IN THE CHIHUAHUAN DESERT: SOIL MOISTURE, N MINERALIZATION AND ION-EXCHANGE RESIN BAGS

EPA Science Inventory

Irrigation and rain-out shelters were used to simulate precipitation patterns of wet and dry years in the northern Chihuahuan Desert. Irrigation provided approximately double the long-term average monthly precipitation. Rain was excluded during the wet season, July-October, to si...

[Skill retention using extraglottic airways in out-of-hospital emergencies: efficacy and long-term results of simulator-based medical education : A prospective follow-up study].

PubMed

Mann, V; Limberg, F; Mann, S T W; Little, S; Müller, M; Sander, M; Röhrig, R

2018-04-11

For emergency medicine personnel (EMP), there is little evidence concerning the adequate timing for refresher courses to maintain routine in the application of extraglottic airways. The aim of this study was to evaluate the efficacy and long-term results of a simulator-based education concept teaching the basic airway management skills with extraglottic airways for EMP and also to draw conclusions concerning the adequate time interval for refresher courses. By use of an explorative, prospective simulator-study with nonphysician EMP, airway management skills using the Larynxmaske Supreme® (LMA‑S) after an introduction lecture were examined. The application of an endotracheal tube (ETT) served as control. Time for preparation of the airway devices, insertion success, and resulting apnea time were assessed immediately after the first introduction lecture (t1) and unannounced 9-12 months thereafter (t2). Comparison of the times for preparation of the LMA‑S at t1 and t2 demonstrated similar results. After the introduction lecture, all paramedics were able to insert the LMA‑S successfully after maximal 2 attempts; 9-12 months later success rates with the LMA‑S were unchanged. Apnea time during airway management was shorter with the LMA‑S compared to the ETT (p < 0.01). Times needed for preparation of the airway devices were similar. The results of this simulator study indicate that a standardized introduction lecture is appropriate to ensure long-lasting procedural skills up to 12 months, so that subsequent refresher courses in basic airway management with the LMA‑S once a year may be adequate. A simulator-based education in basic airway management skills with extraglottic airways is recommended for facilitation of further clinical education according to the current guidelines.

Development of ADOCS controllers and control laws. Volume 3: Simulation results and recommendations

NASA Technical Reports Server (NTRS)

Landis, Kenneth H.; Glusman, Steven I.

1985-01-01

The Advanced Cockpit Controls/Advanced Flight Control System (ACC/AFCS) study was conducted by the Boeing Vertol Company as part of the Army's Advanced Digital/Optical Control System (ADOCS) program. Specifically, the ACC/AFCS investigation was aimed at developing the flight control laws for the ADOCS demonstator aircraft which will provide satisfactory handling qualities for an attack helicopter mission. The three major elements of design considered are as follows: Pilot's integrated Side-Stick Controller (SSC) -- Number of axes controlled; force/displacement characteristics; ergonomic design. Stability and Control Augmentation System (SCAS)--Digital flight control laws for the various mission phases; SCAS mode switching logic. Pilot's Displays--For night/adverse weather conditions, the dynamics of the superimposed symbology presented to the pilot in a format similar to the Advanced Attack Helicopter (AAH) Pilot Night Vision System (PNVS) for each mission phase is a function of SCAS characteristics; display mode switching logic. Results of the five piloted simulations conducted at the Boeing Vertol and NASA-Ames simulation facilities are presented in Volume 3. Conclusions drawn from analysis of pilot rating data and commentary were used to formulate recommendations for the ADOCS demonstrator flight control system design. The ACC/AFCS simulation data also provide an extensive data base to aid the development of advanced flight control system design for future V/STOL aircraft.

Aeolian abrasion on Venus: Preliminary results from the Venus simulator

NASA Technical Reports Server (NTRS)

Marshall, J. R.; Greeley, Ronald; Tucker, D. W.; Pollack, J. B.

1987-01-01

The role of atmospheric pressure on aeolian abrasion was examined in the Venus Simulator with a constant temperature of 737 K. Both the rock target and the impactor were fine-grained basalt. The impactor was a 3 mm diameter angular particle chosen to represent a size of material that is entrainable by the dense Venusian atmosphere and potentially abrasive by virtue of its mass. It was projected at the target 10 to the 5 power times at a velocity of 0.7 m/s. The impactor showed a weight loss of approximately 1.2 x 10 to the -9 power gm per impact with the attrition occurring only at the edges. Results from scanning electron microscope analysis, profilometry, and weight measurement are summarized. It is concluded that particles can incur abrasion at Venusian temperatures even with low impact velocities expected for Venus.

Assessment of long-term knowledge retention following single-day simulation training for uncommon but critical obstetrical events

PubMed Central

Vadnais, Mary A.; Dodge, Laura E.; Awtrey, Christopher S.; Ricciotti, Hope A.; Golen, Toni H.; Hacker, Michele R.

2013-01-01

Objective The objectives were to determine (i) whether simulation training results in short-term and long-term improvement in the management of uncommon but critical obstetrical events and (ii) to determine whether there was additional benefit from annual exposure to the workshop. Methods Physicians completed a pretest to measure knowledge and confidence in the management of eclampsia, shoulder dystocia, postpartum hemorrhage and vacuum-assisted vaginal delivery. They then attended a simulation workshop and immediately completed a posttest. Residents completed the same posttests 4 and 12 months later, and attending physicians completed the posttest at 12 months. Physicians participated in the same simulation workshop 1 year later and then completed a final posttest. Scores were compared using paired t-tests. Results Physicians demonstrated improved knowledge and comfort immediately after simulation. Residents maintained this improvement at 1 year. Attending physicians remained more comfortable managing these scenarios up to 1 year later; however, knowledge retention diminished with time. Repeating the simulation after 1 year brought additional improvement to physicians. Conclusion Simulation training can result in short-term and contribute to long-term improvement in objective measures of knowledge and comfort level in managing uncommon but critical obstetrical events. Repeat exposure to simulation training after 1 year can yield additional benefits. PMID:22191668

Simulated building energy demand biases resulting from the use of representative weather stations

DOE PAGES

Burleyson, Casey D.; Voisin, Nathalie; Taylor, Z. Todd; ...

2017-11-06

Numerical building models are typically forced with weather data from a limited number of “representative cities” or weather stations representing different climate regions. The use of representative weather stations reduces computational costs, but often fails to capture spatial heterogeneity in weather that may be important for simulations aimed at understanding how building stocks respond to a changing climate. Here, we quantify the potential reduction in temperature and load biases from using an increasing number of weather stations over the western U.S. Our novel approach is based on deriving temperature and load time series using incrementally more weather stations, ranging frommore » 8 to roughly 150, to evaluate the ability to capture weather patterns across different seasons. Using 8 stations across the western U.S., one from each IECC climate zone, results in an average absolute summertime temperature bias of ~4.0 °C with respect to a high-resolution gridded dataset. The mean absolute bias drops to ~1.5 °C using all available weather stations. Temperature biases of this magnitude could translate to absolute summertime mean simulated load biases as high as 13.5%. Increasing the size of the domain over which biases are calculated reduces their magnitude as positive and negative biases may cancel out. Using 8 representative weather stations can lead to a 20–40% bias of peak building loads during both summer and winter, a significant error for capacity expansion planners who may use these types of simulations. Using weather stations close to population centers reduces both mean and peak load biases. Our approach could be used by others designing aggregate building simulations to understand the sensitivity to their choice of weather stations used to drive the models.« less

Simulated building energy demand biases resulting from the use of representative weather stations

DOE Office of Scientific and Technical Information (OSTI.GOV)

Burleyson, Casey D.; Voisin, Nathalie; Taylor, Z. Todd

Numerical building models are typically forced with weather data from a limited number of “representative cities” or weather stations representing different climate regions. The use of representative weather stations reduces computational costs, but often fails to capture spatial heterogeneity in weather that may be important for simulations aimed at understanding how building stocks respond to a changing climate. Here, we quantify the potential reduction in temperature and load biases from using an increasing number of weather stations over the western U.S. Our novel approach is based on deriving temperature and load time series using incrementally more weather stations, ranging frommore » 8 to roughly 150, to evaluate the ability to capture weather patterns across different seasons. Using 8 stations across the western U.S., one from each IECC climate zone, results in an average absolute summertime temperature bias of ~4.0 °C with respect to a high-resolution gridded dataset. The mean absolute bias drops to ~1.5 °C using all available weather stations. Temperature biases of this magnitude could translate to absolute summertime mean simulated load biases as high as 13.5%. Increasing the size of the domain over which biases are calculated reduces their magnitude as positive and negative biases may cancel out. Using 8 representative weather stations can lead to a 20–40% bias of peak building loads during both summer and winter, a significant error for capacity expansion planners who may use these types of simulations. Using weather stations close to population centers reduces both mean and peak load biases. Our approach could be used by others designing aggregate building simulations to understand the sensitivity to their choice of weather stations used to drive the models.« less

Economic costs of chronic disease through lost productive life years (PLYs) among Australians aged 45–64 years from 2015 to 2030: results from a microsimulation model

PubMed Central

Schofield, Deborah; Shrestha, Rupendra N; Cunich, Michelle M; Tanton, Robert; Veerman, Lennert; Kelly, Simon J

2016-01-01

Objectives To project the number of older workers with lost productive life years (PLYs) due to chronic disease and resultant lost income; and lost taxes and increased welfare payments from 2015 to 2030. Design, setting and participants Using a microsimulation model, Health&WealthMOD2030, the costs of chronic disease in Australians aged 45–64 were projected to 2030. The model integrates household survey data from the Australian Bureau of Statistics Surveys of Disability, Ageing and Carers (SDACs) 2003 and 2009, output from long-standing microsimulation models (STINMOD (Static Incomes Model) and APPSIM (Australian Population and Policy Simulation Model)) used by various government departments, population and labour force growth data from Treasury, and disease trends data from the Australian Burden of Disease and Injury Study (2003). Respondents aged 45–64 years in the SDACs 2003 and 2009 formed the base population. Main outcome measures Lost PLYs due to chronic disease; resultant lost income, lost taxes and increased welfare payments in 2015, 2020, 2025 and 2030. Results We projected 380 000 (6.4%) people aged 45–64 years with lost PLYs in 2015, increasing to 462 000 (6.5%) in 2030—a 22% increase in absolute numbers. Those with lost PLYs experience the largest reduction in income than any other group in each year compared to those employed full time without a chronic disease, and this income gap widens over time. The total economic loss due to lost PLYs consisted of lost income modelled at $A12.6 billion in 2015, increasing to $A20.5 billion in 2030—a 62.7% increase. Additional costs to the government consisted of increased welfare payments at $A6.2 billion in 2015, increasing to $A7.3 billion in 2030—a 17.7% increase; and a loss of $A3.1 billion in taxes in 2015, increasing to $A4.7 billion in 2030—a growth of 51.6%. Conclusions There is a need for greater investment in effective preventive health interventions which improve workers’ health

The effectiveness of simulation activities on the cognitive abilities of undergraduate third-year nursing students: a randomised control trial.

PubMed

Secomb, Jacinta; McKenna, Lisa; Smith, Colleen

2012-12-01

To provide evidence on the effectiveness of simulation activities on the clinical decision-making abilities of undergraduate nursing students. Based on previous research, it was hypothesised that the higher the cognitive score, the greater the ability a nursing student would have to make informed valid decisions in their clinical practice. Globally, simulation is being espoused as an education method that increases the competence of health professionals. At present, there is very little evidence to support current investment in time and resources. Following ethical approval, fifty-eight third-year undergraduate nursing students were randomised in a pretest-post-test group-parallel controlled trial. The learning environment preferences (LEP) inventory was used to test cognitive abilities in order to refute the null hypothesis that activities in computer-based simulated learning environments have a negative effect on cognitive abilities when compared with activities in skills laboratory simulated learning environments. There was no significant difference in cognitive development following two cycles of simulation activities. Therefore, it is reasonable to assume that two simulation tasks, either computer-based or laboratory-based, have no effect on an undergraduate student's ability to make clinical decisions in practice. However, there was a significant finding for non-English first-language students, which requires further investigation. More longitudinal studies that quantify the education effects of simulation on the cognitive, affective and psychomotor attributes of health science students and professionals from both English-speaking and non-English-speaking backgrounds are urgently required. It is also recommended that to achieve increased participant numbers and prevent non-participation owing to absenteeism, further studies need to be imbedded directly into curricula. This investigation confirms the effect of simulation activities on real-life clinical

Advanced Simulation and Computing Fiscal Year 14 Implementation Plan, Rev. 0.5

DOE Office of Scientific and Technical Information (OSTI.GOV)

Meisner, Robert; McCoy, Michel; Archer, Bill

2013-09-11

The Stockpile Stewardship Program (SSP) is a single, highly integrated technical program for maintaining the surety and reliability of the U.S. nuclear stockpile. The SSP uses nuclear test data, computational modeling and simulation, and experimental facilities to advance understanding of nuclear weapons. It includes stockpile surveillance, experimental research, development and engineering programs, and an appropriately scaled production capability to support stockpile requirements. This integrated national program requires the continued use of experimental facilities and programs, and the computational enhancements to support these programs. The Advanced Simulation and Computing Program (ASC) is a cornerstone of the SSP, providing simulation capabilities andmore » computational resources that support annual stockpile assessment and certification, study advanced nuclear weapons design and manufacturing processes, analyze accident scenarios and weapons aging, and provide the tools to enable stockpile Life Extension Programs (LEPs) and the resolution of Significant Finding Investigations (SFIs). This requires a balanced resource, including technical staff, hardware, simulation software, and computer science solutions. In its first decade, the ASC strategy focused on demonstrating simulation capabilities of unprecedented scale in three spatial dimensions. In its second decade, ASC is now focused on increasing predictive capabilities in a three-dimensional (3D) simulation environment while maintaining support to the SSP. The program continues to improve its unique tools for solving progressively more difficult stockpile problems (sufficient resolution, dimensionality, and scientific details), quantify critical margins and uncertainties, and resolve increasingly difficult analyses needed for the SSP. Moreover, ASC’s business model is integrated and focused on requirements-driven products that address long-standing technical questions related to enhanced predictive

Simulation Framework for Rapid Entry, Descent, and Landing (EDL) Analysis, Phase 2 Results

NASA Technical Reports Server (NTRS)

Murri, Daniel G.

2011-01-01

The NASA Engineering and Safety Center (NESC) was requested to establish the Simulation Framework for Rapid Entry, Descent, and Landing (EDL) Analysis assessment, which involved development of an enhanced simulation architecture using the Program to Optimize Simulated Trajectories II simulation tool. The assessment was requested to enhance the capability of the Agency to provide rapid evaluation of EDL characteristics in systems analysis studies, preliminary design, mission development and execution, and time-critical assessments. Many of the new simulation framework capabilities were developed to support the Agency EDL-Systems Analysis (SA) team that is conducting studies of the technologies and architectures that are required to enable human and higher mass robotic missions to Mars. The findings, observations, and recommendations from the NESC are provided in this report.

Northern Forest DroughtNet: Initial results from a multi-year throughfall manipulation experiment in New Hampshire

NASA Astrophysics Data System (ADS)

McIntire, C.; Vadeboncoeur, M. A.; Coble, A.; Jennings, K.; Asbjornsen, H.

2016-12-01

Climate change is likely to affect the Northern Forest region through the increased frequency and severity of drought events. However, our understanding of how the Northern Forest, which is adapted to humid temperate conditions, will respond to moderate to extreme droughts is limited. Given the important role that these forests play in protecting ecosystem services and in supplying forest products, enhancing our knowledge about impacts of drought is critical to ensuring effective forest management and adaptation to climate change. The Northern Forest DroughtNet project aims to simulate a four-year severe drought by removing 55% of the incoming throughfall; thus representing the 99th percentile of annual precipitation based on historic precipitation data in Durham, NH. This is accomplished using two replicated 900 m2 throughfall removal structures consisting of a network of gutters that capture and divert incoming precipitation away from the established treatment area. Data presented here will address the ecosystem response to the drought treatment over the course of the first year of the experiment as well as validate the effectiveness and artifacts of the throughfall removal structure. Response variables of interest include soil moisture content, above and below ground biomass production, litterfall, decomposition rates, leaf water potential, foliar gas exchange, and whole tree transpiration rates. Preliminary findings provide insight into the effectiveness of using throughfall manipulation experiments in a temperate forest ecosystem to simulate an extreme drought event, as well as initial tree physiological and growth responses in relation to soil moisture availability and the implications for future climate change impacts.

The effects of simulated fog and motion on simulator sickness in a driving simulator and the duration of after-effects.

PubMed

Dziuda, Lukasz; Biernacki, Marcin P; Baran, Paulina M; Truszczyński, Olaf E

2014-05-01

In the study, we checked: 1) how the simulator test conditions affect the severity of simulator sickness symptoms; 2) how the severity of simulator sickness symptoms changes over time; and 3) whether the conditions of the simulator test affect the severity of these symptoms in different ways, depending on the time that has elapsed since the performance of the task in the simulator. We studied 12 men aged 24-33 years (M = 28.8, SD = 3.26) using a truck simulator. The SSQ questionnaire was used to assess the severity of the symptoms of simulator sickness. Each of the subjects performed three 30-minute tasks running along the same route in a driving simulator. Each of these tasks was carried out in a different simulator configuration: A) fixed base platform with poor visibility; B) fixed base platform with good visibility; and C) motion base platform with good visibility. The measurement of the severity of the simulator sickness symptoms took place in five consecutive intervals. The results of the analysis showed that the simulator test conditions affect in different ways the severity of the simulator sickness symptoms, depending on the time which has elapsed since performing the task on the simulator. The simulator sickness symptoms persisted at the highest level for the test conditions involving the motion base platform. Also, when performing the tasks on the motion base platform, the severity of the simulator sickness symptoms varied depending on the time that had elapsed since performing the task. Specifically, the addition of motion to the simulation increased the oculomotor and disorientation symptoms reported as well as the duration of the after-effects. Copyright © 2013 Elsevier Ltd and The Ergonomics Society. All rights reserved.

Analysis of the Effect of Interior Nudging on Temperature and Precipitation Distributions of Multi-year Regional Climate Simulations

NASA Astrophysics Data System (ADS)

Nolte, C. G.; Otte, T. L.; Bowden, J. H.; Otte, M. J.

2010-12-01

There is disagreement in the regional climate modeling community as to the appropriateness of the use of internal nudging. Some investigators argue that the regional model should be minimally constrained and allowed to respond to regional-scale forcing, while others have noted that in the absence of interior nudging, significant large-scale discrepancies develop between the regional model solution and the driving coarse-scale fields. These discrepancies lead to reduced confidence in the ability of regional climate models to dynamically downscale global climate model simulations under climate change scenarios, and detract from the usability of the regional simulations for impact assessments. The advantages and limitations of interior nudging schemes for regional climate modeling are investigated in this study. Multi-year simulations using the WRF model driven by reanalysis data over the continental United States at 36km resolution are conducted using spectral nudging, grid point nudging, and for a base case without interior nudging. The means, distributions, and inter-annual variability of temperature and precipitation will be evaluated in comparison to regional analyses.

[Initial results with the Munich knee simulator].

PubMed

Frey, M; Riener, R; Burgkart, R; Pröll, T

2002-01-01

In orthopaedics more than 50 different clinical knee joint evaluation tests exist that have to be trained in orthopaedic education. Often it is not possible to obtain sufficient practical training in a clinical environment. The training can be improved by Virtual Reality technology. In the frame of the Munich Knee Joint Simulation project an artificial leg with anatomical properties is attached by a force-torque sensor to an industrial robot. The recorded forces and torques are the input for a simple biomechanical model of the human knee joint. The robot is controlled in such way that the user gets the feeling he moves a real leg. The leg is embedded in a realistic environment with a couch and a patient on it.

Effect of Different Sampling Schedules on Results of Bioavailability and Bioequivalence Studies: Evaluation by Means of Monte Carlo Simulations.

PubMed

Kano, Eunice Kazue; Chiann, Chang; Fukuda, Kazuo; Porta, Valentina

2017-08-01

Bioavailability and bioequivalence study is one of the most frequently performed investigations in clinical trials. Bioequivalence testing is based on the assumption that 2 drug products will be therapeutically equivalent when they are equivalent in the rate and extent to which the active drug ingredient or therapeutic moiety is absorbed and becomes available at the site of drug action. In recent years there has been a significant growth in published papers that use in silico studies based on mathematical simulations to analyze pharmacokinetic and pharmacodynamic properties of drugs, including bioavailability and bioequivalence aspects. The goal of this study is to evaluate the usefulness of in silico studies as a tool in the planning of bioequivalence, bioavailability and other pharmacokinetic assays, e.g., to determine an appropriate sampling schedule. Monte Carlo simulations were used to define adequate blood sampling schedules for a bioequivalence assay comparing 2 different formulations of cefadroxil oral suspensions. In silico bioequivalence studies comparing different formulation of cefadroxil oral suspensions using various sampling schedules were performed using models. An in vivo study was conducted to confirm in silico results. The results of in silico and in vivo bioequivalence studies demonstrated that schedules with fewer sampling times are as efficient as schedules with larger numbers of sampling times in the assessment of bioequivalence, but only if T max is included as a sampling time. It was also concluded that in silico studies are useful tools in the planning of bioequivalence, bioavailability and other pharmacokinetic in vivo assays. © Georg Thieme Verlag KG Stuttgart · New York.

A theoretical and simulation study of the contact discontinuities based on a Vlasov simulation code

NASA Astrophysics Data System (ADS)

Tsai, T. C.; Lyu, L. H.; Chao, J. K.; Chen, M. Q.; Tsai, W. H.

2009-12-01

Contact discontinuity (CD) is the simplest solution that can be obtained from the magnetohydrodynamics (MHD) Rankine-Hugoniot jump conditions. Due to the limitations of the previous kinetic simulation models, the stability of the CD has become a controversial issue in the past 10 years. The stability of the CD is reexamined analytically and numerically. Our theoretical analysis shows that the electron temperature profile and the ion temperature profile must be out of phase across the CD if the CD structure is to be stable in the electron time scale and with zero electron heat flux on either side of the CD. Both a newly developed fourth-order implicit electrostatic Vlasov simulation code and an electromagnetic finite-size particle code are used to examine the stability and the electrostatic nature of the CD structure. Our theoretical prediction is verified by both simulations. Our results of Vlasov simulation also indicate that a simulation with initial electron temperature profile and ion temperature profile varying in phase across the CD will undergo very transient changes in the electron time scale but will relax into a quasi-steady CD structure within a few ion plasma oscillation periods if a real ion-electron mass ratio is used in the simulation and if the boundary conditions allow nonzero heat flux to be presented at the boundaries of the simulation box. The simulation results of this study indicate that the Vlasov simulation is a powerful tool to study nonlinear phenomena with nonperiodic boundary conditions and with nonzero heat flux at the boundaries of the simulation box.

Forty years experience in developing and using rainfall simulators under tropical and Mediterranean conditions

NASA Astrophysics Data System (ADS)

Pla-Sentís, Ildefonso; Nacci, Silvana

2010-05-01

Rainfall simulation has been used as a practical tool for evaluating the interaction of falling water drops on the soil surface, to measure both stability of soil aggregates to drop impact and water infiltration rates. In both cases it is tried to simulate the effects of natural rainfall, which usually occurs at very different, variable and erratic rates and intensities. One of the main arguments against the use of rainfall simulators is the difficulty to reproduce the size, final velocity and kinetic energy of the drops in natural rainfall. Since the early 70´s we have been developing and using different kinds of rainfall simulators, both at laboratory and field levels, and under tropical and Mediterranean soil and climate conditions, in flat and sloping lands. They have been mainly used to evaluate the relative effects of different land use and management, including different cropping systems, tillage practices, surface soil conditioning, surface covers, etc. on soil water infiltration, on runoff and on erosion. Our experience is that in any case it is impossible to reproduce the variable size distribution and terminal velocity of raindrops, and the variable changes in intensity of natural storms, under a particular climate condition. In spite of this, with the use of rainfall simulators it is possible to obtain very good information, which if it is properly interpreted in relation to each particular condition (land and crop management, rainfall characteristics, measurement conditions, etc.) may be used as one of the parameters for deducing and modelling soil water balance and soil moisture regime under different land use and management and variable climate conditions. Due to the possibility for a better control of the intensity of simulated rainfall and of the size of water drops, and the possibility to make more repeated measurements under very variable soil and land conditions, both in the laboratory and specially in the field, the better results have been

Effects of three years of simulated nitrogen deposition on soil nitrogen dynamics and greenhouse gas emissions in a Korean pine plantation of northeast China.

PubMed

Song, Lei; Tian, Peng; Zhang, Jinbo; Jin, Guangze

2017-12-31

Continuously enhanced nitrogen (N) deposition alters the pattern of N and carbon (C) transformations, and thus influences greenhouse gas emissions. It is necessary to clarify the effect of N deposition on greenhouse gas emissions and soil N dynamics for an accurate assessment of C and N budgets under increasing N deposition. In this study, four simulated N deposition treatments (control [CK: no N addition], low-N [L: 20kgNha -1 yr -1 ], medium-N [M: 40kgNha -1 yr -1 ], and high-N [H: 80kgNha -1 yr -1 ]) were operated from 2014. Carbon dioxide, methane and nitrous oxide fluxes were monitored semimonthly, as were soil variables such as temperature, moisture and the concentrations of total dissolved N (TDN), NO 3 - , NO 2 - , NH 4 + , and dissolved organic N (DON) in soil solutions. The simulated N deposition resulted in a significant increase in TDN, NO 3 - and DON concentrations in soil solutions. The average CO 2 emission rate ranged from 222.6mgCO 2 m -2 h -1 in CK to 233.7mgCO 2 m -2 h -1 in the high-N treatment. Three years of simulated N deposition had no effect on soil CO 2 emission, which was mainly controlled by soil temperature. The mean N 2 O emission rate during the whole 3years was 0.02mgN 2 Om -2 h -1 for CK, which increased significantly to 0.05mgN 2 Om -2 h -1 in the high-N treatment. The N 2 O emission rate positively correlated with NH 4 + concentrations, and negatively correlated with soil moisture. The average CH 4 flux during the whole 3years was -0.74μgCH 4 m -2 h -1 in CK, which increased to 1.41μgCH 4 m -2 h -1 in the low-N treatment. CH 4 flux positively correlated with NO 3 - concentrations. These results indicate that short-term N deposition did not affect soil CO 2 emissions, while CH 4 and N 2 O emissions were sensitive to N deposition. Copyright © 2017 Elsevier B.V. All rights reserved.

Semblance analysis to assess GPR data from a five-year forensic study of simulated clandestine graves

NASA Astrophysics Data System (ADS)

Booth, Adam D.; Pringle, Jamie K.

2016-02-01

Ground penetrating radar (GPR) surveys have proven useful for locating clandestine graves in a number of forensic searches. There has been extensive research into the geophysical monitoring of simulated clandestine graves in different burial scenarios and ground conditions. Whilst these studies have been used to suggest optimum dominant radar frequencies, the data themselves have not been quantitatively analysed to-date. This study uses a common-offset configuration of semblance analysis, both to characterise velocity trends from GPR diffraction hyperbolae and, since the magnitude of a semblance response is proportional to signal-to-noise ratio, to quantify the strength of a forensic GPR response. 2D GPR profiles were acquired over a simulated clandestine burial, with a wrapped-pig cadaver monitored at three-month intervals between 2008 and 2013 with GPR antennas of three different centre-frequencies (110, 225 and 450 MHz). The GPR response to the cadaver was a strong diffraction hyperbola. Results show, in contrast to resistivity surveys, that semblance analysis have little sensitivity to changes attributable to decomposition, and only a subtle influence from seasonality: velocity increases (0.01-0.02 m/ns) were observed in summer, associated with a decrease (5-10%) in peak semblance magnitude, SM, and potentially in the reflectivity of the cadaver. The lowest-frequency antennas consistently gave the highest signal-to-noise ratio although the grave was nonetheless detectable by all frequencies trialled. These observations suggest that forensic GPR surveys could be undertaken with little seasonal hindrance. Whilst GPR analysis cannot currently provide a quantitative diagnostic proxy for time-since-burial, the consistency of responses suggests that graves will remain detectable beyond the five years shown here.

Pilot age and expertise predict flight simulator performance: a 3-year longitudinal study.

PubMed

Taylor, Joy L; Kennedy, Quinn; Noda, Art; Yesavage, Jerome A

2007-02-27

Expert knowledge may compensate for age-related declines in basic cognitive and sensory-motor abilities in some skill domains. We investigated the influence of age and aviation expertise (indexed by Federal Aviation Administration pilot ratings) on longitudinal flight simulator performance. Over a 3-year period, 118 general aviation pilots aged 40 to 69 years were tested annually, in which their flight performance was scored in terms of 1) executing air-traffic controller communications; 2) traffic avoidance; 3) scanning cockpit instruments; 4) executing an approach to landing; and 5) a flight summary score. More expert pilots had better flight summary scores at baseline and showed less decline over time. Secondary analyses revealed that expertise effects were most evident in the accuracy of executing aviation communications, the measure on which performance declined most sharply over time. Regarding age, even though older pilots initially performed worse than younger pilots, over time older pilots showed less decline in flight summary scores than younger pilots. Secondary analyses revealed that the oldest pilots did well over time because their traffic avoidance performance improved more vs younger pilots. These longitudinal findings support previous cross-sectional studies in aviation as well as non-aviation domains, which demonstrated the advantageous effect of prior experience and specialized expertise on older adults' skilled cognitive performances.

Simulation-based education with deliberate practice may improve intraoperative handoff skills: a pilot study.

PubMed

Pukenas, Erin W; Dodson, Gregory; Deal, Edward R; Gratz, Irwin; Allen, Elaine; Burden, Amanda R

2014-11-01

To examine the results of simulation-based education with deliberate practice on the acquisition of handoff skills by studying resident intraoperative handoff communication performances. Preinvention and postintervention pilot study. Simulated operating room of a university-affiliated hospital. Resident handoff performances during 27 encounters simulating elective surgery were studied. Ten residents (CA-1, CA-2, and CA-3) participated in a one-day simulation-based handoff course. Each resident repeated simulated handoffs to deliberately practice with an intraoperative handoff checklist. One year later, 7 of the 10 residents participated in simulated intraoperative handoffs. All handoffs were videotaped and later scored for accuracy by trained raters. A handoff assessment tool was used to characterize the type and frequency of communication failures. The percentage of handoff errors and omissions were compared before simulation and postsimulation-based education with deliberate practice and at one year following the course. Initially, the overall communication failure rate, defined as the percentage of handoff omissions plus errors, was 29.7%. After deliberate practice with the intraoperative handoff checklist, the communication failure rate decreased to 16.8%, and decreased further to 13.2% one year after the course. Simulation-based education using deliberate practice may result in improved intraoperative handoff communication and retention of skills at one year. Copyright © 2014 Elsevier Inc. All rights reserved.

Simulation of centennial-scale drought events over eastern China during the past 1500 years

NASA Astrophysics Data System (ADS)

Sun, Weiyi; Liu, Jian; Wang, Zhiyuan

2017-02-01

The characteristics and causes of centennial-scale drought events over eastern China during the past 1500 years were explored based on simulations of the Community Earth System Model (CESM). The results show that centennial- scale drought events over eastern China occurred during the periods of 622-735 (Drought period 1, D1) and 1420-1516 (Drought period 2, D2) over the past 1500 years, which is comparable with climate proxy data. In D1, the drought center occurred in northern China and the Yangtze River valley; however, in southern China, precipitation was much more than usual. In D2, decreased precipitation was found across almost the whole region of eastern China. The direct cause of these two drought events was the weakened East Asian summer monsoon, and the specific process was closely linked to the air-sea interaction of the Indo-Pacific Ocean. In D1, regions of maximum cooling were observed over the western Pacific, which may have led to anomalous subsidence, weakening the Walker circulation, and reducing the northward transport of water vapor. Additionally, upward motion occurred over southern China, strengthening convection and increasing precipitation. In D2, owing to the decrease in the SST, subsidence dominated the North Indian Ocean, blocking the low-level cross-equatorial flow, enhancing the tropical westerly anomalies, and reducing the northward transport of moisture. Additionally, descending motion appeared in eastern China, subsequently decreasing the precipitation over the whole region of eastern China. The anomalous cooling of the Indo-Pacific Ocean SST may have been caused by the persistently low solar irradiation in D1; whereas, in D2, this characteristic may have been influenced not only by persistently low solar irradiation, but frequent volcanic eruptions too.

Analysis of spirometry results in hospitalized patients aged over 65 years.

PubMed

Wróblewska, Izabela; Oleśniewicz, Piotr; Kurpas, Donata; Sołtysik, Mariusz; Błaszczuk, Jerzy

2015-01-01

The growing population of the elderly, as well as the occurrence of coexisting diseases and polypharmacy, is the reason why diseases of patients aged $65 years belong to the major issues of the contemporary medicine. Among the most frequent diseases of the elderly, there are respiratory system diseases. They are difficult to diagnose because of the patient group specificity, which is the reason for increased mortality among seniors, caused by underdiagnosis. The study objective was to assess the factors influencing spirometry results in hospitalized patients aged ≥65 years with respiratory system disorders. In the research, 217 (100%) patients aged ≥65 years who underwent spirometry at the Regional Medical Center of the Jelenia Góra Valley Hospital in Poland were analyzed. In the statistical analysis, the STATISTICA 9.1 program, the t-test, the Shapiro-Wilk test, the ANOVA test, and the Scheffé's test were applied. The majority of the patients (59.4%) were treated in the hospital. The most frequent diagnosis was malignant neoplasm (18%). The study showed a statistically significant dependence between the forced vital capacity (FVC), forced expiratory volume in 1 second (FEV1), and FEV1/FVC parameters and the time of hospitalization, as well as between the FVC and FEV1 parameters and the age of patients. The FVC parameter values turned out to be dependent on the main diagnosis. Highest results were noted in patients with the diagnosis of sleep apnea or benign neoplasm. A low FVC index can reflect restrictive ventilation defects, which was supported by the performed analyses. Highest FEV1/FVC values were observed in nonsmokers, which confirms the influence of nicotine addiction on the incidence of respiratory system diseases. The respondents' sex and the established diagnosis statistically significantly influenced the FVC index result, and the diet influenced the FEV1/FVC parameter result.

Near-Infrared Spectroscopic Measurements of Calf Muscle during Walking at Simulated Reduced Gravity - Preliminary Results

NASA Technical Reports Server (NTRS)

Ellerby, Gwenn E. C.; Lee, Stuart M. C.; Stroud, Leah; Norcross, Jason; Gernhardt, Michael; Soller, Babs R.

2008-01-01

Consideration for lunar and planetary exploration space suit design can be enhanced by investigating the physiologic responses of individual muscles during locomotion in reduced gravity. Near-infrared spectroscopy (NIRS) provides a non-invasive method to study the physiology of individual muscles in ambulatory subjects during reduced gravity simulations. PURPOSE: To investigate calf muscle oxygen saturation (SmO2) and pH during reduced gravity walking at varying treadmill inclines and added mass conditions using NIRS. METHODS: Four male subjects aged 42.3 +/- 1.7 years (mean +/- SE) and weighing 77.9 +/- 2.4 kg walked at a moderate speed (3.2 +/- 0.2 km/h) on a treadmill at inclines of 0, 10, 20, and 30%. Unsuited subjects were attached to a partial gravity simulator which unloaded the subject to simulate body weight plus the additional weight of a space suit (121 kg) in lunar gravity (0.17G). Masses of 0, 11, 23, and 34 kg were added to the subject and then unloaded to maintain constant weight. Spectra were collected from the lateral gastrocnemius (LG), and SmO2 and pH were calculated using previously published methods (Yang et al. 2007 Optics Express ; Soller et al. 2008 J Appl Physiol). The effects of incline and added mass on SmO2 and pH were analyzed through repeated measures ANOVA. RESULTS: SmO2 and pH were both unchanged by added mass (p>0.05), so data from trials at the same incline were averaged. LG SmO2 decreased significantly with increasing incline (p=0.003) from 61.1 +/- 2.0% at 0% incline to 48.7 +/- 2.6% at 30% incline, while pH was unchanged by incline (p=0.12). CONCLUSION: Increasing the incline (and thus work performed) during walking causes the LG to extract more oxygen from the blood supply, presumably to support the increased metabolic cost of uphill walking. The lack of an effect of incline on pH may indicate that, while the intensity of exercise has increased, the LG has not reached a level of work above the anaerobic threshold. In these

First Year Results from the Fermi Gamma-Ray Space Telescope

NASA Technical Reports Server (NTRS)

Hays, Elizabeth

2009-01-01

After one year of survey observations and more than 70 billion triggers, Fermi is revealing an unprecedented view of the high energy gamma-ray sky. The observatory .carries two instruments, the Gamma-ray Burst Monitor (GB, 8 keV - 40 MeV) and the Large Area Telescope (LAT, 20 MeV greater than or equal to 300 GeV), which in combination cover over 7 orders of magnitude in energy for transient phenomena. The LAT provides substantially more sensitivity than previous instruments in this waveband and has opened up the energy window from 10-100 GeV. The first year has produced many important results, from detections of extremely energetic and distant gamma-ray bursts, to monitoring daily variations in emission caused by massive black holes at the cores of galaxies, to identifying a new population of gamma-ray bright pulsars, to measuring the spectrum of diffuse emission from our own. Galaxy and the spectrum of the local cosmic electrons. I'll review highlights from the first year and discuss how the data are answering questions from the past and raising new ones for the future.

Simulated Rainfall experiments on burned areas

NASA Astrophysics Data System (ADS)

Rulli, Maria Cristina

2010-05-01

Simulated Rainfall experiments were carried out in a Mediterranean area located in Italy, immediately after a forest fire occurrence, to evaluate the effects of forest fire on soil hydraulic properties, runoff and erosion. The selected study area was frequently affected by fire in the last years. Two adjacent 30 mq plots were set up with common physiographic features, and the same fire history, except for the last fire, which burned only one of them. Since both plots were previously subject to the passage of fire 6 years before the last one, one compares the hydrologic response and erosion of an area recently burned (B00) with that of an area burnt 6 years before (B06). Several rainfall simulations were carried out considering different pre-event soil moisture conditions where each rainfall simulation consisted of a single 60 minute application of rainfall with constant intensity of about 76 mm/h. The results show runoff ratio, evaluated for different pre-event soil moisture conditions, ranging from 0 to 2% for B06 plot, and from 21 to 41% for B00. Runoff ratio for the recently burned plot was 60 times higher than for the plot burned six years before, under wet conditions, and 20 times higher, under very wet conditions. A large increase in sediment production also was measured in B00 plot, as compared with that in B06 plot. Suspended sediment yield from B00 plot was more than two orders of magnitude higher than that from B06 plot in all the simulated events. The high runoff and soil losses measured immediately after burning indicate that effective post-fire rehabilitation programs must be carried out to reduce flood risk and soil erosion in recently burned areas. However, the results for the plot burned six year prior show that recovery of the hydrological properties of the soil occurs after the transient post fire modification.

Additional road markings as an indication of speed limits: results of a field experiment and a driving simulator study.

PubMed

Daniels, Stijn; Vanrie, Jan; Dreesen, An; Brijs, Tom

2010-05-01

Although speed limits are indicated by road signs, road users are not always aware, while driving, of the actual speed limit on a given road segment. The Roads and Traffic Agency developed additional road markings in order to support driver decisions on speed on 70 km/h roads in Flanders-Belgium. In this paper the results are presented of two evaluation studies, both a field study and a simulator study, on the effects of the additional road markings on speed behaviour. The results of the field study showed no substantial effect of the markings on speed behaviour. Neither did the simulator study, with slightly different stimuli. Nevertheless an effect on lateral position was noticed in the simulator study, showing at least some effect of the markings. The role of conspicuity of design elements and expectations towards traffic environments is discussed. Both studies illustrate well some strengths and weaknesses of observational field studies compared to experimental simulator studies. Copyright (c) 2009 Elsevier Ltd. All rights reserved.

Impact of Assimilation on Heavy Rainfall Simulations Using WRF Model: Sensitivity of Assimilation Results to Background Error Statistics

NASA Astrophysics Data System (ADS)

Rakesh, V.; Kantharao, B.

2017-03-01

Data assimilation is considered as one of the effective tools for improving forecast skill of mesoscale models. However, for optimum utilization and effective assimilation of observations, many factors need to be taken into account while designing data assimilation methodology. One of the critical components that determines the amount and propagation observation information into the analysis, is model background error statistics (BES). The objective of this study is to quantify how BES in data assimilation impacts on simulation of heavy rainfall events over a southern state in India, Karnataka. Simulations of 40 heavy rainfall events were carried out using Weather Research and Forecasting Model with and without data assimilation. The assimilation experiments were conducted using global and regional BES while the experiment with no assimilation was used as the baseline for assessing the impact of data assimilation. The simulated rainfall is verified against high-resolution rain-gage observations over Karnataka. Statistical evaluation using several accuracy and skill measures shows that data assimilation has improved the heavy rainfall simulation. Our results showed that the experiment using regional BES outperformed the one which used global BES. Critical thermo-dynamic variables conducive for heavy rainfall like convective available potential energy simulated using regional BES is more realistic compared to global BES. It is pointed out that these results have important practical implications in design of forecast platforms while decision-making during extreme weather events

Analysis of spirometry results in hospitalized patients aged over 65 years

PubMed Central

Wróblewska, Izabela; Oleśniewicz, Piotr; Kurpas, Donata; Sołtysik, Mariusz; Błaszczuk, Jerzy

2015-01-01

Introduction and objective The growing population of the elderly, as well as the occurrence of coexisting diseases and polypharmacy, is the reason why diseases of patients aged $65 years belong to the major issues of the contemporary medicine. Among the most frequent diseases of the elderly, there are respiratory system diseases. They are difficult to diagnose because of the patient group specificity, which is the reason for increased mortality among seniors, caused by underdiagnosis. The study objective was to assess the factors influencing spirometry results in hospitalized patients aged ≥65 years with respiratory system disorders. Material and methods In the research, 217 (100%) patients aged ≥65 years who underwent spirometry at the Regional Medical Center of the Jelenia Góra Valley Hospital in Poland were analyzed. In the statistical analysis, the STATISTICA 9.1 program, the t-test, the Shapiro–Wilk test, the ANOVA test, and the Scheffé’s test were applied. Results The majority of the patients (59.4%) were treated in the hospital. The most frequent diagnosis was malignant neoplasm (18%). The study showed a statistically significant dependence between the forced vital capacity (FVC), forced expiratory volume in 1 second (FEV1), and FEV1/FVC parameters and the time of hospitalization, as well as between the FVC and FEV1 parameters and the age of patients. The FVC parameter values turned out to be dependent on the main diagnosis. Highest results were noted in patients with the diagnosis of sleep apnea or benign neoplasm. A low FVC index can reflect restrictive ventilation defects, which was supported by the performed analyses. Highest FEV1/FVC values were observed in nonsmokers, which confirms the influence of nicotine addiction on the incidence of respiratory system diseases. Conclusion The respondents’ sex and the established diagnosis statistically significantly influenced the FVC index result, and the diet influenced the FEV1/FVC parameter result

Upgrades for the CMS simulation

DOE PAGES

Lange, D. J.; Hildreth, M.; Ivantchenko, V. N.; ...

2015-05-22

Over the past several years, the CMS experiment has made significant changes to its detector simulation application. The geometry has been generalized to include modifications being made to the CMS detector for 2015 operations, as well as model improvements to the simulation geometry of the current CMS detector and the implementation of a number of approved and possible future detector configurations. These include both completely new tracker and calorimetry systems. We have completed the transition to Geant4 version 10, we have made significant progress in reducing the CPU resources required to run our Geant4 simulation. These have been achieved throughmore » both technical improvements and through numerical techniques. Substantial speed improvements have been achieved without changing the physics validation benchmarks that the experiment uses to validate our simulation application for use in production. As a result, we will discuss the methods that we implemented and the corresponding demonstrated performance improvements deployed for our 2015 simulation application.« less

Renewed circulation scheme of the Baltic Sea - based on the 40-year simulation with GETM.

NASA Astrophysics Data System (ADS)

Maljutenko, Ilja; Raudsepp, Urmas

2015-04-01

The general circulation of the Baltic Sea has been characterized as cyclonic in all sub-basins based on numerous measurements and model simulations. From the long-term hydrodynamical simulation our model results have verified the general cyclonic circulation in the Baltic Proper and in the Gulf of Bothnia, but the Gulf of Finland and the Gulf of Riga have shown tendency to anticyclonic circulation. We have applied the General Estuarine Transport Model ( GETM ) for the period of 1966 - 2006 with a 1 nautical mile horizontal resolution and density adaptive bottom following vertical coordinates to make it possible to simulate horizontal and vertical density gradients with better precision. The atmospheric forcing from dynamically downscaled ERA40-HIRLAM and parametrized lateral boundary conditions are applied. Model simulation show close agreement with measurements conducted in the main monitoring stations in the BS during the simulation period. The geostrophic adjustment of density driven currents along with the upward salinity flux due to entrainment could explain the anticyclonic circulation and strong coastal current. Mean vertical velocities show that upward and downward movements are forming closed vertical circulation loops along the bottom slope of the Baltic Proper and the Gulf of Bothnia. The model has also reproduced patchy vertical movement across the BS with some distinctive areas of upward advective fluxes in the GoF along the thalweg. The distinctive areas of deepwater upwelling are also evident in the Gdansk Basin, western Gotland Basin, northern Gotland Basin and in the northen part of the Bothnia Sea.

Testing simulations of intra- and inter-annual variation in the plant production response to elevated CO(2) against measurements from an 11-year FACE experiment on grazed pasture.

PubMed

Li, Frank Yonghong; Newton, Paul C D; Lieffering, Mark

2014-01-01

Ecosystem models play a crucial role in understanding and evaluating the combined impacts of rising atmospheric CO2 concentration and changing climate on terrestrial ecosystems. However, we are not aware of any studies where the capacity of models to simulate intra- and inter-annual variation in responses to elevated CO2 has been tested against long-term experimental data. Here we tested how well the ecosystem model APSIM/AgPasture was able to simulate the results from a free air carbon dioxide enrichment (FACE) experiment on grazed pasture. At this FACE site, during 11 years of CO2 enrichment, a wide range in annual plant production response to CO2 (-6 to +28%) was observed. As well as running the full model, which includes three plant CO2 response functions (plant photosynthesis, nitrogen (N) demand and stomatal conductance), we also tested the influence of these three functions on model predictions. Model/data comparisons showed that: (i) overall the model over-predicted the mean annual plant production response to CO2 (18.5% cf 13.1%) largely because years with small or negative responses to CO2 were not well simulated; (ii) in general seasonal and inter-annual variation in plant production responses to elevated CO2 were well represented by the model; (iii) the observed CO2 enhancement in overall mean legume content was well simulated but year-to-year variation in legume content was poorly captured by the model; (iv) the best fit of the model to the data required all three CO2 response functions to be invoked; (v) using actual legume content and reduced N fixation rate under elevated CO2 in the model provided the best fit to the experimental data. We conclude that in temperate grasslands the N dynamics (particularly the legume content and N fixation activity) play a critical role in pasture production responses to elevated CO2 , and are processes for model improvement. © 2013 John Wiley & Sons Ltd.

Results of a simulator test comparing two display concepts for piloted flight-path-angle control

NASA Technical Reports Server (NTRS)

Kelley, W. W.

1978-01-01

Results of a simulator experiment which was conducted in order to compare pilot gamma-control performance using two display formats are reported. Pilots flew a variable flight path angle tracking task in the landing configuration. Pilot and airplane performance parameters were recorded and pilot comments noted for each case.

SUBWATERSHEDS OF THE UPPER SAN PEDRO BASIN WITH PERCENT DIFFERENCE BETWEEN RESULTS FROM TWO SWAT SIMULATIONS

EPA Science Inventory

Subwatersheds of the Upper San Pedro basin with percent difference between results from two SWAT simulations run through AGWA: one using the 1973 NALC landcover for model parameterization, and the other using the 1997 NALC landcover.

Disaster Medicine Training Through Simulations for Fourth-Year Students.

ERIC Educational Resources Information Center

Cloutier, Marc G.; Cowan, Michael L.

1986-01-01

The use of a six-day multiple-simulation exercise in the military disaster medical services training program of the Uniformed Services University of the Health Sciences is described. It is the second part of a clerkship that includes a classroom/laboratory phase using a disaster problem-solving board game. (MSE)

Simulated Effects of Year 2030 Water-Use and Land-Use Changes on Streamflow near the Interstate-495 Corridor, Assabet and Upper Charles River Basins, Eastern Massachusetts

USGS Publications Warehouse

Carlson, Carl S.; Desimone, Leslie A.; Weiskel, Peter K.

2008-01-01

Continued population growth and land development for commercial, industrial, and residential uses have created concerns regarding the future supply of potable water and the quantity of ground water discharging to streams in the area of Interstate 495 in eastern Massachusetts. Two ground-water models developed in 2002-2004 for the Assabet and Upper Charles River Basins were used to simulate water supply and land-use scenarios relevant for the entire Interstate-495 corridor. Future population growth, water demands, and commercial and residential growth were projected for year 2030 by the Metropolitan Area Planning Council. To assess the effects of future development on subbasin streamflows, seven scenarios were simulated by using existing computer-based ground-water-flow models with the data projected for year 2030. The scenarios incorporate three categories of projected 2030 water- and land-use data: (1) 2030 water use, (2) 2030 land use, and (3) a combination of 2030 water use and 2030 land use. Hydrologic, land-use, and water-use data from 1997 through 2001 for the Assabet River Basin study and 1989 through 1998 for the Upper Charles River Basin study were used to represent current conditions - referred to as 'basecase' conditions - in each basin to which each 2030 scenario was compared. The effects of projected 2030 land- and water-use change on streamflows in the Assabet River Basin depended upon the time of year, the hydrologic position of the subbasin in the larger basin, and the relative areas of new commercial and residential development projected for a subbasin. Effects of water use and land use on streamflow were evaluated by comparing average monthly nonstorm streamflow (base flow) for March and September simulated by using the models. The greatest decreases in streamflow (up to 76 percent in one subbasin), compared to the basecase, occurred in September, when streamflows are naturally at their lowest level. By contrast, simulated March streamflows

Economic costs of chronic disease through lost productive life years (PLYs) among Australians aged 45-64 years from 2015 to 2030: results from a microsimulation model.

PubMed

Schofield, Deborah; Shrestha, Rupendra N; Cunich, Michelle M; Tanton, Robert; Veerman, Lennert; Kelly, Simon J; Passey, Megan E

2016-09-22

To project the number of older workers with lost productive life years (PLYs) due to chronic disease and resultant lost income; and lost taxes and increased welfare payments from 2015 to 2030. Using a microsimulation model, Health&WealthMOD2030, the costs of chronic disease in Australians aged 45-64 were projected to 2030. The model integrates household survey data from the Australian Bureau of Statistics Surveys of Disability, Ageing and Carers (SDACs) 2003 and 2009, output from long-standing microsimulation models (STINMOD (Static Incomes Model) and APPSIM (Australian Population and Policy Simulation Model)) used by various government departments, population and labour force growth data from Treasury, and disease trends data from the Australian Burden of Disease and Injury Study (2003). Respondents aged 45-64 years in the SDACs 2003 and 2009 formed the base population. Lost PLYs due to chronic disease; resultant lost income, lost taxes and increased welfare payments in 2015, 2020, 2025 and 2030. We projected 380 000 (6.4%) people aged 45-64 years with lost PLYs in 2015, increasing to 462 000 (6.5%) in 2030-a 22% increase in absolute numbers. Those with lost PLYs experience the largest reduction in income than any other group in each year compared to those employed full time without a chronic disease, and this income gap widens over time. The total economic loss due to lost PLYs consisted of lost income modelled at $A12.6 billion in 2015, increasing to $A20.5 billion in 2030-a 62.7% increase. Additional costs to the government consisted of increased welfare payments at $A6.2 billion in 2015, increasing to $A7.3 billion in 2030-a 17.7% increase; and a loss of $A3.1 billion in taxes in 2015, increasing to $A4.7 billion in 2030-a growth of 51.6%. There is a need for greater investment in effective preventive health interventions which improve workers' health and work capacity. Published by the BMJ Publishing Group Limited. For permission to use (where not

Faster Aerodynamic Simulation With Cart3D

NASA Technical Reports Server (NTRS)

2003-01-01

A NASA-developed aerodynamic simulation tool is ensuring the safety of future space operations while providing designers and engineers with an automated, highly accurate computer simulation suite. Cart3D, co-winner of NASA's 2002 Software of the Year award, is the result of over 10 years of research and software development conducted by Michael Aftosmis and Dr. John Melton of Ames Research Center and Professor Marsha Berger of the Courant Institute at New York University. Cart3D offers a revolutionary approach to computational fluid dynamics (CFD), the computer simulation of how fluids and gases flow around an object of a particular design. By fusing technological advancements in diverse fields such as mineralogy, computer graphics, computational geometry, and fluid dynamics, the software provides a new industrial geometry processing and fluid analysis capability with unsurpassed automation and efficiency.

JIRAM infrared observations of Jupiter Aurorae: results of the first year.

NASA Astrophysics Data System (ADS)

Mura, A.; Adriani, A.; Altieri, F.; Dinelli, B. M.; Moriconi, M. L.; Migliorini, A.; Bolton, S. J.; Connerney, J. E. P.; Cicchetti, A.; Noschese, R.; Sindoni, G.; Tosi, F.; Filacchione, G.; Fabiano, F.; Piccioni, G.; Turrini, D.; Amoroso, M.; Plainaki, C.; Olivieri, A.; Gerard, J.-C.

2017-09-01

JIRAM (Jovian Infrared Auroral Mapper) is an imaging spectrometer on board the Juno spacecraft, specifically designed to observe the aurorae of Jupiter. Here we show results on JIRAM's data after one year of observations. The footprints of Io, Europa and Ganymede have also been observed and characterized.

Thermophysical Properties of Undercooled Alloys: An Overview of the Molecular Simulation Approaches

PubMed Central

Lv, Yong J.; Chen, Min

2011-01-01

We review the studies on the thermophysical properties of undercooled metals and alloys by molecular simulations in recent years. The simulation methods of melting temperature, enthalpy, specific heat, surface tension, diffusion coefficient and viscosity are introduced and the simulated results are summarized. By comparing the experimental results and various theoretical models, the temperature and the composition dependences of the thermophysical properties in undercooled regime are discussed. PMID:21339987

Results from the International Heliophysical Year (IHY)

NASA Technical Reports Server (NTRS)

Davila, Joseph M.

2010-01-01

The International Heliophysical Year (IHY) involved the effort of thousands of scientists from over 70 countries, ended in February 2009. The major objectives of the IHY included over 60 collaborative studies of universal physical processes in the solar system, the deployment of arrays of small instruments to observe heliophysical processes, a unique program of educational and public outreach, and the preservation of the history of the IGY, during a two year period. A follow on effort, the International Space Weather Initiative (ISWI) is designed to build on the momentum developed during the IHY to develop the capability to observe, understand, and predict space weather phenomena.

Simulation: Perceptions of First Year Associate Degree Nursing Students

ERIC Educational Resources Information Center

Dougherty, Suzanne V.

2011-01-01

It was the purpose of this study to determine if there is a relationship between student satisfaction with high-fidelity-patient simulation experience and self-confidence in learning among student nurses. The population was associate nursing degree students. The study measured by the students' perceptions of their satisfaction and self-confidence.…

Learning Performance with Interactive Simulations in Medical Education: Lessons Learned from Results of Learning Complex Physiological Models with the HAEMOdynamics SIMulator

ERIC Educational Resources Information Center

Holzinger, Andreas; Kickmeier-Rust, Michael D.; Wassertheurer, Sigi; Hessinger, Michael

2009-01-01

Objective: Since simulations are often accepted uncritically, with excessive emphasis being placed on technological sophistication at the expense of underlying psychological and educational theories, we evaluated the learning performance of simulation software, in order to gain insight into the proper use of simulations for application in medical…

One year of downwelling spectral radiance measurements from 100 to 1400 cm-1 at Dome Concordia: Results in clear conditions

NASA Astrophysics Data System (ADS)

Rizzi, R.; Arosio, C.; Maestri, T.; Palchetti, L.; Bianchini, G.; Del Guasta, M.

2016-09-01

The present work examines downwelling radiance spectra measured at the ground during 2013 by a Far Infrared Fourier Transform Spectrometer at Dome C, Antarctica. A tropospheric backscatter and depolarization lidar is also deployed at same site, and a radiosonde system is routinely operative. The measurements allow characterization of the water vapor and clouds infrared properties in Antarctica under all sky conditions. In this paper we specifically discuss cloud detection and the analysis in clear sky condition, required for the discussion of the results obtained in cloudy conditions. First, the paper discusses the procedures adopted for the quality control of spectra acquired automatically. Then it describes the classification procedure used to discriminate spectra measured in clear sky from cloudy conditions. Finally a selection is performed and 66 clear cases, spanning the whole year, are compared to simulations. The computation of layer molecular optical depth is performed with line-by-line techniques and a convolution to simulate the Radiation Explorer in the Far InfraRed-Prototype for Applications and Development (REFIR-PAD) measurements; the downwelling radiance for selected clear cases is computed with a state-of-the-art adding-doubling code. The mean difference over all selected cases between simulated and measured radiance is within experimental error for all the selected microwindows except for the negative residuals found for all microwindows in the range 200 to 400 cm-1, with largest values around 295.1 cm-1. The paper discusses possible reasons for the discrepancy and identifies the incorrect magnitude of the water vapor total absorption coefficient as the cause of such large negative radiance bias below 400 cm-1.

Cosmological N-body Simulation

NASA Astrophysics Data System (ADS)

Lake, George

1994-05-01

.90ex> }}} The ``N'' in N-body calculations has doubled every year for the last two decades. To continue this trend, the UW N-body group is working on algorithms for the fast evaluation of gravitational forces on parallel computers and establishing rigorous standards for the computations. In these algorithms, the computational cost per time step is ~ 10(3) pairwise forces per particle. A new adaptive time integrator enables us to perform high quality integrations that are fully temporally and spatially adaptive. SPH--smoothed particle hydrodynamics will be added to simulate the effects of dissipating gas and magnetic fields. The importance of these calculations is two-fold. First, they determine the nonlinear consequences of theories for the structure of the Universe. Second, they are essential for the interpretation of observations. Every galaxy has six coordinates of velocity and position. Observations determine two sky coordinates and a line of sight velocity that bundles universal expansion (distance) together with a random velocity created by the mass distribution. Simulations are needed to determine the underlying structure and masses. The importance of simulations has moved from ex post facto explanation to an integral part of planning large observational programs. I will show why high quality simulations with ``large N'' are essential to accomplish our scientific goals. This year, our simulations have N >~ 10(7) . This is sufficient to tackle some niche problems, but well short of our 5 year goal--simulating The Sloan Digital Sky Survey using a few Billion particles (a Teraflop-year simulation). Extrapolating past trends, we would have to ``wait'' 7 years for this hundred-fold improvement. Like past gains, significant changes in the computational methods are required for these advances. I will describe new algorithms, algorithmic hacks and a dedicated computer to perform Billion particle simulations. Finally, I will describe research that can be enabled by

Sensitivity Analysis of Different Shapes of a Plastic Optical Fiber-Based Immunosensor for Escherichia coli: Simulation and Experimental Results.

PubMed

Rodrigues, Domingos M C; Lopes, Rafaela N; Franco, Marcos A R; Werneck, Marcelo M; Allil, Regina C S B

2017-12-19

Conventional pathogen detection methods require trained personnel, specialized laboratories and can take days to provide a result. Thus, portable biosensors with rapid detection response are vital for the current needs for in-loco quality assays. In this work the authors analyze the characteristics of an immunosensor based on the evanescent field in plastic optical fibers with macro curvature by comparing experimental with simulated results. The work studies different shapes of evanescent-wave based fiber optic sensors, adopting a computational modeling to evaluate the probes with the best sensitivity. The simulation showed that for a U-Shaped sensor, the best results can be achieved with a sensor of 980 µm diameter by 5.0 mm in curvature for refractive index sensing, whereas the meander-shaped sensor with 250 μm in diameter with radius of curvature of 1.5 mm, showed better sensitivity for either bacteria and refractive index (RI) sensing. Then, an immunosensor was developed, firstly to measure refractive index and after that, functionalized to detect Escherichia coli . Based on the results with the simulation, we conducted studies with a real sensor for RI measurements and for Escherichia coli detection aiming to establish the best diameter and curvature radius in order to obtain an optimized sensor. On comparing the experimental results with predictions made from the modelling, good agreements were obtained. The simulations performed allowed the evaluation of new geometric configurations of biosensors that can be easily constructed and that promise improved sensitivity.

Simulation and Laboratory results of the Hard X-ray Polarimeter: X-Calibur

NASA Astrophysics Data System (ADS)

Guo, Qingzhen; Beilicke, M.; Kislat, F.; Krawczynski, H.

2014-01-01

X-ray polarimetry promises to give qualitatively new information about high-energy sources, such as binary black hole (BH) systems, Microquasars, active galactic nuclei (AGN), GRBs, etc. We designed, built and tested a hard X-ray polarimeter 'X-Calibur' to be flown in the focal plane of the InFOCuS grazing incidence hard X-ray telescope in 2014. X-Calibur combines a low-Z Compton scatterer with a CZT detector assembly to measure the polarization of 20- 80 keV X-rays making use of the fact that polarized photons Compton scatter preferentially perpendicular to the E field orientation. X-Calibur achieves a high detection efficiency of order unity. We optimized of the design of the instrument based on Monte Carlo simulations of polarized and unpolarized X-ray beams and of the most important background components. We have calibrated and tested X-Calibur extensively in the laboratory at Washington University and at the Cornell High-Energy Synchrotron Source (CHESS). Measurements using the highly polarized synchrotron beam at CHESS confirm the polarization sensitivity of the instrument. In this talk we report on the optimization of the design of the instrument based on Monte Carlo simulations, as well as results of laboratory calibration measurements characterizing the performance of the instrument.

Test of a Cardiology Patient Simulator with Students in Fourth-Year Electives.

ERIC Educational Resources Information Center

Ewy, Gordon A.; And Others

1987-01-01

Students at five medical schools participated in an evaluation of a cardiology patient simulator (CPS), a life-size mannequin capable of simulating a wide variety of cardiovascular conditions. The CPS enhances learning both the knowledge and the skills necessary to perform a bedside cardiovascular evaluation. (Author/MLW)

Total knee replacement-cementless tibial fixation with screws: 10-year results.

PubMed

Ersan, Önder; Öztürk, Alper; Çatma, Mehmet Faruk; Ünlü, Serhan; Akdoğan, Mutlu; Ateş, Yalım

2017-12-01

The aim of this study was to evaluate the long term clinical and radiological results of cementless total knee replacement. A total of 51 knees of 49 patients (33 female and 16 male; mean age: 61.6 years (range, 29-66 years)) who underwent TKR surgery with a posterior stabilized hydroxyapatite coated knee implant were included in this study. All of the tibial components were fixed with screws. The HSS scores were examined preoperatively and at the final follow-up. Radiological assessment was performed with Knee Society evaluating and scoring system. Kaplan-Meier survival analysis was performed to rule out the survival of the tibial component. The mean HSS scores were 45.8 (range 38-60) and 88.1 (range 61-93), preoperatively and at the final follow-up respectively. Complete radiological assessment was performed for 48 knees. Lucent lines at the tibial component were observed in 4 patients; one of these patients underwent a revision surgery due to the loosening of the tibial component. The 10-year survival rate of a tibial component was 98%. Cementless total knee replacement has satisfactory long term clinical results. Primary fixation of the tibial component with screws provides adequate stability even in elderly patients with good bone quality. Level IV, Therapeutic study. Copyright © 2017 Turkish Association of Orthopaedics and Traumatology. Production and hosting by Elsevier B.V. All rights reserved.

Atmospheric dynamical changes as a contributor to deglacial climate variability: results from an ensemble of transient deglacial simulations

NASA Astrophysics Data System (ADS)

Andres, Heather; Tarasov, Lev

2017-04-01

The atmosphere is often assumed to play a passive role in centennial- to millennial-timescale climate variations of the last deglaciation due to its short response times ( years) and the absence of abrupt changes in external climate forcings. Nevertheless, atmospheric dynamical responses to changes in ice sheet topography and albedo can affect the entire Northern Hemisphere through the altering of Rossby stationary wave patterns and changes to the North Atlantic eddy-driven jet. These responses appear sensitive to the particular configuration of Northern Hemisphere land ice, so small changes have the potential to reorganize atmospheric circulation with impacts on precipitation distributions, ocean surface currents and sea ice extent. Indirect proxy evidence, idealized theoretical studies, and "snapshot" simulations performed at different periods during the last glacial cycle indicate that between the Last Glacial Maximum and the preindustrial period the North Atlantic eddy-driven jet weakened, became less zonally-oriented, and exhibited greater variability. How the transition (or transitions) between the glacial atmospheric state and the interglacial state occurred is less clear. To address this question, we performed an ensemble of transient simulations of the last deglaciation using the Planet Simulator coupled atmosphere-ocean-vegetation-sea ice model (PlaSim, at an atmospheric resolution of T42) forced by variants of the GLAC1-D deglacial ice sheet chronology. We characterize simulated changes in stationary wave patterns over this period as well as changes in the strength and position of the North Atlantic eddy-driven jet. In particular, we document the range of timescales for these changes and compare the simulated climate signatures of these transitions to data archives of precipitation and sea ice extent.

Nitrate Leaching From Intensive Forest Management on Abandonded Agricultural Land: Fifth-Year Results

Treesearch

Thomas M. Williams; Charles Gresham

2002-01-01

This report is on the fifth year results of a cooperative research project to examine water quality impacts of maximizing plantation growth on abandoned agricultural land, first reported after two years in the Ninth Southern Silvicultural Research Conference. The study, located on International Paper's Southland Experimental Forest at Bainbridge GA, examines...

Year-long simulation of gaseous and particulate air pollutants in India

NASA Astrophysics Data System (ADS)

Kota, Sri Harsha; Guo, Hao; Myllyvirta, Lauri; Hu, Jianlin; Sahu, Shovan Kumar; Garaga, Rajyalakshmi; Ying, Qi; Gao, Aifang; Dahiya, Sunil; Wang, Yuan; Zhang, Hongliang

2018-05-01

Severe pollution events occur frequently in India but few studies have investigated the characteristics, sources, and control strategies for the whole country. A year-long simulation was carried out in India to provide detailed information of spatial and temporal distribution of gas species and particulate matter (PM). The concentrations of O3, NO2, SO2, CO, as well as PM2.5 and its components in 2015 were predicted using Weather Research Forecasting (WRF) and the Community Multiscale Air Quality (CMAQ) models. Model performance was validated against available observations from ground based national ambient air quality monitoring stations in major cities. Model performance of O3 does not always meet the criteria suggested by the US Environmental Protection Agency (EPA) but that of PM2.5 meets suggested criteria by previous studies. The performance of model was better on days with high O3 and PM2.5 levels. Concentrations of PM2.5, NO2, CO and SO2 were highest in the Indo-Gangetic region, including northern and eastern India. PM2.5 concentrations were higher during winter and lower during monsoon season. Winter nitrate concentrations were 160-230% higher than yearly average. In contrast, the fraction of sulfate in total PM2.5 was maximum in monsoon and least in winter, due to decrease in temperature and solar radiation intensity in winter. Except in southern India, where sulfate was the major component of PM2.5, primary organic aerosol (POA) fraction in PM2.5 was highest in all regions of the country. Fractions of secondary components were higher on bad days than on good days in these cities, indicating the importance of control of precursors for secondary pollutants in India.

Teaching first-year medical students physiology: does the human patient simulator allow for more effective teaching?

PubMed

Tan, G M; Ti, L K; Suresh, S; Ho, B S; Lee, T L

2002-05-01

Although the Human Patient Simulator (HPS) is an effective teaching tool in many medical fields, literature supporting its use in the teaching of physiology to medical students is lacking. This study investigated the effectiveness of HPS-based teaching of cardiovascular physiology to first-year medical students. Two hundred and ten first-year medical students were scheduled to our HPS laboratory with the purpose of demonstrating "physiology in action". Students were divided into groups of 19-25 each, and attended a lecture followed by a HPS session. Using a theatre-type simulator complete with mannequin, anaesthesia machine and monitors (METI, Sarasota FL), the scenarios of hypovolaemia, sepsis, and cardiac failure were run to demonstrate the physiological changes that occur with changes in preload, afterload, and cardiac contractility. Each student was given a true/false test before, and again after the HPS session, followed by a survey of their learning experience. There was marked improvement in test scores after the HPS session (82.1% vs. 64.6%, P < 0.001). Most of the students felt that HPS was a better teaching tool (94.5%) and raised more questions (76.5%) than lectures. They wanted more topics to be taught this way (96%), as they could apply and re-enforce textbook knowledge, and visualise real-time changes. However, they felt that their experience could have been enhanced with more time and smaller groups. HPS is an excellent teaching tool as it stimulates student curiosity and makes knowledge acquisition and understanding easier. It is highly desirable to be incorporated into the teaching of physiology.

Hybrid poplar on two anthracite coal-mine spoils: 10-year results

Treesearch

Miroslaw M. Czapowskyj

1978-01-01

Unrooted dormant cuttings of 28 hybrid poplar clones were planted on two graded anthracite coal-mine spoils derived from sandstone or from glacial till. Ten-year results show that the plantation survived very well (82 percent), but that growth was extremely varied. Spoil Characteristics and performance of individual clones are presented.

Gyrokinetic micro-turbulence simulations on the NERSC 16-way SMP IBM SP computer: experiences and performance results

NASA Astrophysics Data System (ADS)

Ethier, Stephane; Lin, Zhihong

2001-10-01

Earlier this year, the National Energy Research Scientific Computing center (NERSC) took delivery of the second most powerful computer in the world. With its 2,528 processors running at a peak performance of 1.5 GFlops, this IBM SP machine has a theoretical performance of almost 3.8 TFlops. To efficiently harness such computing power in one single code is not an easy task and requires a good knowledge of the computer's architecture. Here we present the steps that we followed to improve our gyrokinetic micro-turbulence code GTC in order to take advantage of the new 16-way shared memory nodes of the NERSC IBM SP. Performance results are shown as well as details about the improved mixed-mode MPI-OpenMP model that we use. The enhancements to the code allowed us to tackle much bigger problem sizes, getting closer to our goal of simulating an ITER-size tokamak with both kinetic ions and electrons.(This work is supported by DOE Contract No. DE-AC02-76CH03073 (PPPL), and in part by the DOE Fusion SciDAC Project.)

Vehicle Animation Software (VAS) to Animate Results Obtained from Vehicle Handling and Rollover Simulations and Tests

DOT National Transportation Integrated Search

1991-04-01

Results from vehicle computer simulations usually take the form of numeric data or graphs. While these graphs provide the investigator with the insight into vehicle behavior, it may be difficult to use these graphs to assess complex vehicle motion. C...

1030/1090 MHz Interference Simulator Technical Description and Initial Results

DOT National Transportation Integrated Search

2001-04-27

The 1030/1090 MHz Interference Simulator has been under development since March 1999, and currently replicates the interference production and operation of the existing surveillance systems and several proposed new Mode S applications. Efforts are on...

Differences in Faculty and Standardized Patient Scores on Professionalism for Second-Year Podiatric Medical Students During a Standardized Simulated Patient Encounter.

PubMed

Mahoney, James M; Vardaxis, Vassilios; Anwar, Noreen; Hagenbucher, Jacob

2018-03-01

This study examined the differences between faculty and trained standardized patient (SP) evaluations on student professionalism during a second-year podiatric medicine standardized simulated patient encounter. Forty-nine second-year podiatric medicine students were evaluated for their professionalism behavior. Eleven SPs performed an assessment in real-time, and one faculty member performed a secondary assessment after observing a videotape of the encounter. Five domains were chosen for evaluation from a validated professionalism assessment tool. Significant differences were identified in the professionalism domains of "build a relationship" ( P = .008), "gather information" ( P = .001), and share information ( P = .002), where the faculty scored the students higher than the SP for 24.5%, 18.9%, and 26.5% of the cases, respectively. In addition, the faculty scores were higher than the SP scores in all of the "gather information" subdomains; however, the difference in scores was significant only in the "question appropriately" ( P = .001) and "listen and clarify" ( P = .003) subdomains. This study showed that professionalism scores for second-year podiatric medical students during a simulated patient encounter varied significantly between faculty and SPs. Further consideration needs to be given to determine the source of these differences.

MoSeS: Modelling and Simulation for e-Social Science.

PubMed

Townend, Paul; Xu, Jie; Birkin, Mark; Turner, Andy; Wu, Belinda

2009-07-13

MoSeS (Modelling and Simulation for e-Social Science) is a research node of the National Centre for e-Social Science. MoSeS uses e-Science techniques to execute an events-driven model that simulates discrete demographic processes; this allows us to project the UK population 25 years into the future. This paper describes the architecture, simulation methodology and latest results obtained by MoSeS.

Simulation of streamflow and sediment transport in two surface-coal-mined basins in Fayette County, Pennsylvania

USGS Publications Warehouse

Sams, J. I.; Witt, E. C.

1995-01-01

The Hydrological Simulation Program - Fortran (HSPF) was used to simulate streamflow and sediment transport in two surface-mined basins of Fayette County, Pa. Hydrologic data from the Stony Fork Basin (0.93 square miles) was used to calibrate HSPF parameters. The calibrated parameters were applied to an HSPF model of the Poplar Run Basin (8.83 square miles) to evaluate the transfer value of model parameters. The results of this investigation provide information to the Pennsylvania Department of Environmental Resources, Bureau of Mining and Reclamation, regarding the value of the simulated hydrologic data for use in cumulative hydrologic-impact assessments of surface-mined basins. The calibration period was October 1, 1985, through September 30, 1988 (water years 1986-88). The simulated data were representative of the observed data from the Stony Fork Basin. Mean simulated streamflow was 1.64 cubic feet per second compared to measured streamflow of 1.58 cubic feet per second for the 3-year period. The difference between the observed and simulated peak stormflow ranged from 4.0 to 59.7 percent for 12 storms. The simulated sediment load for the 1987 water year was 127.14 tons (0.21 ton per acre), which compares to a measured sediment load of 147.09 tons (0.25 ton per acre). The total simulated suspended-sediment load for the 3-year period was 538.2 tons (0.30 ton per acre per year), which compares to a measured sediment load of 467.61 tons (0.26 ton per acre per year). The model was verified by comparing observed and simulated data from October 1, 1988, through September 30, 1989. The results obtained were comparable to those from the calibration period. The simulated mean daily discharge was representative of the range of data observed from the basin and of the frequency with which specific discharges were equalled or exceeded. The calibrated and verified parameters from the Stony Fork model were applied to an HSPF model of the Poplar Run Basin. The two basins are in

Simulation of the Tsunami Resulting from the M 9.2 2004 Sumatra-Andaman Earthquake - Dynamic Rupture vs. Seismic Inversion Source Model

NASA Astrophysics Data System (ADS)

Vater, Stefan; Behrens, Jörn

2017-04-01

Simulations of historic tsunami events such as the 2004 Sumatra or the 2011 Tohoku event are usually initialized using earthquake sources resulting from inversion of seismic data. Also, other data from ocean buoys etc. is sometimes included in the derivation of the source model. The associated tsunami event can often be well simulated in this way, and the results show high correlation with measured data. However, it is unclear how the derived source model compares to the particular earthquake event. In this study we use the results from dynamic rupture simulations obtained with SeisSol, a software package based on an ADER-DG discretization solving the spontaneous dynamic earthquake rupture problem with high-order accuracy in space and time. The tsunami model is based on a second-order Runge-Kutta discontinuous Galerkin (RKDG) scheme on triangular grids and features a robust wetting and drying scheme for the simulation of inundation events at the coast. Adaptive mesh refinement enables the efficient computation of large domains, while at the same time it allows for high local resolution and geometric accuracy. The results are compared to measured data and results using earthquake sources based on inversion. With the approach of using the output of actual dynamic rupture simulations, we can estimate the influence of different earthquake parameters. Furthermore, the comparison to other source models enables a thorough comparison and validation of important tsunami parameters, such as the runup at the coast. This work is part of the ASCETE (Advanced Simulation of Coupled Earthquake and Tsunami Events) project, which aims at an improved understanding of the coupling between the earthquake and the generated tsunami event.

Simulation of 20-year deterioration of acrylic IOLs using severe accelerated deterioration tests.

PubMed

Kawai, Kenji; Hayakawa, Kenji; Suzuki, Takahiro

2012-09-20

To investigate IOL deterioration by conducting severe accelerated deterioration testing of acrylic IOLs. Department of Ophthalmology, Tokai University School of Medicine Methods: Severe accelerated deterioration tests performed on 7 types of acrylic IOLs simulated 20 years of deterioration. IOLs were placed in a screw tube bottle containing ultra-pure water and kept in an oven (100°C) for 115 days. Deterioration was determined based the outer appearance of the IOL in water and under air-dried conditions using an optical microscope. For accelerated deterioration of polymeric material, the elapse of 115 days was considered to be equivalent to 20 years based on the Arrhenius equation. All of the IOLs in the hydrophobic acrylic group except for AU6 showed glistening-like opacity. The entire optical sections of MA60BM and SA60AT became yellowish white in color. Hydrophilic acrylic IOL HP60M showed no opacity at any of the time points examined. Our data based on accelerated testing showed differences in water content to play a major role in transparency. There were differences in opacity among manufacturers. The method we have used for determining the relative time of IOL deterioration might not represent the exact clinical setting, but the appearance of the materials would presumably be very similar to that seen in patients.

The Titan Haze Simulation Experiment: Latest Laboratory Results and Dedicated Plasma Chemistry Model

NASA Astrophysics Data System (ADS)

Sciamma-O'Brien, Ella; Raymond, Alexander; Mazur, Eric; Salama, Farid

2018-06-01

Here, we present the latest results on the gas and solid phase analyses in the Titan Haze Simulation (THS) experiment. The THS experiment, developed at NASA Ames’ COSmIC facility is a unique experimental platform that allows us to simulate Titan’s complex atmospheric chemistry at Titan-like temperature (200 K) by cooling down N2-CH4-based mixtures in a supersonic expansion before inducing the chemistry by plasma.Gas phase: The residence time of the jet-accelerated gas in the active plasma region is less than 4 µs, which results in a truncated chemistry enabling us to control how far in the chain of reactions the chemistry is processing. By adding heavier molecules in the initial gas mixture, it is then possible to study the first and intermediate steps of Titan’s atmospheric chemistry as well as specific chemical pathways, as demonstrated by mass spectrometry and comparison to Cassini CAPS data [1]. A new model was recently developed to simulate the plasma chemistry in the THS. Calculated mass spectra produced by this model are in good agreement with the experimental THS mass spectra, confirming that the short residence time in the plasma cavity limits the growth of larger species [2].Solid phase: Scanning electron microscopy and infrared spectroscopy have been used to investigate the effect of the initial gas mixture on the morphology of the THS Titan aerosol analogs as well as on the level and nature of the nitrogen incorporation into these aerosols. A comparison to Cassini VIMS observational data has shown that the THS aerosols produced in simpler mixtures, i.e., that contain more nitrogen and where the N-incorporation is in isocyanide-type molecules instead of nitriles, are more representative of Titan’s aerosols [3]. In addition, a new optical constant facility has been developed at NASA Ames that allows us to determine the complex refractive indices of THS Titan aerosol analogs from NIR to FIR (0.76-222 cm-1). The facility and preliminary results

Prediction of Thorough QT study results using action potential simulations based on ion channel screens.

PubMed

Mirams, Gary R; Davies, Mark R; Brough, Stephen J; Bridgland-Taylor, Matthew H; Cui, Yi; Gavaghan, David J; Abi-Gerges, Najah

2014-01-01

Detection of drug-induced pro-arrhythmic risk is a primary concern for pharmaceutical companies and regulators. Increased risk is linked to prolongation of the QT interval on the body surface ECG. Recent studies have shown that multiple ion channel interactions can be required to predict changes in ventricular repolarisation and therefore QT intervals. In this study we attempt to predict the result of the human clinical Thorough QT (TQT) study, using multiple ion channel screening which is available early in drug development. Ion current reduction was measured, in the presence of marketed drugs which have had a TQT study, for channels encoded by hERG, CaV1.2, NaV1.5, KCNQ1/MinK, and Kv4.3/KChIP2.2. The screen was performed on two platforms - IonWorks Quattro (all 5 channels, 34 compounds), and IonWorks Barracuda (hERG & CaV1.2, 26 compounds). Concentration-effect curves were fitted to the resulting data, and used to calculate a percentage reduction in each current at a given concentration. Action potential simulations were then performed using the ten Tusscher and Panfilov (2006), Grandi et al. (2010) and O'Hara et al. (2011) human ventricular action potential models, pacing at 1Hz and running to steady state, for a range of concentrations. We compared simulated action potential duration predictions with the QT prolongation observed in the TQT studies. At the estimated concentrations, simulations tended to underestimate any observed QT prolongation. When considering a wider range of concentrations, and conventional patch clamp rather than screening data for hERG, prolongation of ≥5ms was predicted with up to 79% sensitivity and 100% specificity. This study provides a proof-of-principle for the prediction of human TQT study results using data available early in drug development. We highlight a number of areas that need refinement to improve the method's predictive power, but the results suggest that such approaches will provide a useful tool in cardiac safety

Near-Earth Asteroid Tracking (NEAT): First Year Results

NASA Astrophysics Data System (ADS)

Helin, E. F.; Rabinowitz, D. L.; Pravdo, S. H.; Lawrence, K. J.

1997-07-01

The successful detection of Near-Earth Asteroids (NEAs) has been demonstrated by the Near-Earth Asteroid Tracking (NEAT) program at the Jet Propulsion Laboratory during its first year of operation. The NEAT CCD camera system is installed on the U. S. Air Force 1-m GEODSS telescope in Maui. Using state-of-the-art software and hardware, the system initiates nightly transmitted observing script from JPL, moves the telescopes for successive exposures of the selected fields, detects moving objects as faint as V=20.5 in 40 s exposures, determines their astrometric positions, and downloads the data for review at JPL in the morning. The NEAT system is detecting NEAs larger than 200m, comets, and other unique objects at a rate competitive with current operating systems, and bright enough for important physical studies on moderate-sized telescopes. NEAT has detected over 10,000 asteroids over a wide range of magnitudes, demonstrating the excellent capability of the NEAT system. Fifty-five percent of the detections are new objects and over 900 of them have been followed on a second night to receive designation from the Minor Planet Center. 14 NEAs (9 Amors, 4 Apollos, and 1 Aten) have been discovered since March 1996. Also, 2 long period comets and 1996 PW, an asteroidal object with an orbit of a long-period comet, with an eccentricity of 0.992 and orbital period of 5900 years. Program discoveries will be reviewed along with analysis of results pertaining to the discovery efficiency, distribution on the sky, range of orbits and magnitudes. Related abstract: Lawrence, K., et al., 1997 DPS

Analysis of year-to-year ozone variation over the subtropical western Pacific region using EP_TOMS data and CCSR/NIES nudging CTM

NASA Astrophysics Data System (ADS)

Zhou, L. B.; Akiyoshi, H.; Kawahira, K.

2003-10-01

The year-to-year ozone variation over the subtropical western Pacific region is studied, especially the ozone lows in the 1996/1997, 1998/1999, and 2001/2002 winters, using the Earth Probe Total Ozone Mapping Spectrometer (EP_TOMS) ozone data from August 1996 to July 2002. Regression analyses show that dynamical signals, such as the quasi-biennial oscillation, play an important role in determining total ozone variation. A nudging chemical transport model (CTM) is used to simulate the year-to-year ozone variation and explain the mechanism for producing ozone lows in a three-dimensional distribution of ozone. The CTM was developed using the Center for Climate System Research/National Institute for Environmental Studies (CCSR/NIES) atmospheric general circulation model and introducing a nudging process for temperature and horizontal wind velocity. The year-to-year ozone variation, especially the winter ozone low, is well simulated by the model excluding heterogeneous reaction processes between 45°S and 45°N latitude. Results show that the year-to-year ozone variation is mainly controlled by dynamical transport processes.

A 2000-year European Mean Summer Temperature Reconstruction from the PAGES 2k Regional Network and Comparison to Millennium-Length Forced Model Simulations

NASA Astrophysics Data System (ADS)

Smerdon, J. E.; Büntgen, U.; Ljungqvist, F. C.; Esper, J.; Fernández-Donado, L.; Gonzalez-Rouco, F. J.; Luterbacher, J.; McCarroll, D.; Wagner, S.; Wahl, E. R.; Wanner, H.; Werner, J.; Zorita, E.

2012-12-01

A reconstruction of mean European summer (JJA) land temperatures from 138 B.C.E. to 2003 C.E. is presented and compared to 37 forced transient simulations of the last millennium from coupled General Circulation Models (CGCMs). Eleven annually resolved tree-ring and documentary records from ten European countries/regions were used for the reconstruction and compiled as part of the Euro_Med working group contribution to the PAGES 2k Regional Network. Records were selected based upon their summer temperature signal, annual resolution, and time-continuous sampling. All tree-ring data were detrended using the Regional Curve Standardization (RCS) method to retain low-frequency variance in the resulting mean chronologies. The calibration time series was the area-weighted JJA temperature computed from the CRUTEM4v dataset over a European land domain (35°-70°N, 10°W-40°E). A nested 'Composite-Plus-Scale' reconstruction was derived using nine nests reflecting the availability of predictors back in time. Each nest was calculated by standardizing the available predictor series over the calibration interval, and subsequently calculating a weighted composite in which each proxy was multiplied by its correlation with the target index. The CPS methodology was implemented using a resampling scheme that uses 104 years for calibration. The initial calibration period extended from 1850-1953 C.E. and was incremented by one year until reaching the final period of 1900-2003 C.E., yielding a total of 51 reconstructions for each nest. Within each calibration step, the 50 years excluded from calibration were used for validation. Validation statistics across all reconstruction ensemble members within each nest indicate skillful reconstructions (RE: 0.42-0.64; CE: 0.26-0.54) and are all above the maximum validation statistics achieved in an ensemble of red noise benchmarking experiments. Warm periods in the derived reconstruction during the 1st, 2nd, and 7th-12th centuries compare to

Internet Training Resulted in Improved Trainee Performance in a Simulated Opioid-Poisoned Patient as Measured by Checklist.

PubMed

Kim, Hong; Heverling, Harry; Cordeiro, Michael; Vasquez, Vanessa; Stolbach, Andrew

2016-09-01

Opioid overdose is a leading cause of death in the USA. Internet-based teaching can improve medical knowledge among trainees, but there are limited data to show the effect of Internet-based teaching on clinical competence in medical training, including management of opioid poisoning. We used an ecological design to assess the effect of an Internet-based teaching module on the management of a simulated opioid-poisoned patient. We enrolled two consecutive classes of post-graduate year-1 residents from a single emergency medicine program. The first group (RA) was instructed to read a toxicology textbook chapter and the second group (IT) took a brief Internet training module. All participants subsequently managed a simulated opioid-poisoned patient. The participants' performance was evaluated with two types of checklist (simple and time-weighted), along with global assessment scores. Internet-trained participants performed better on both checklist scales. The difference between mean simple checklist scores by the IT and RA groups was 0.23 (95 % CI, 0.016-0.44). The difference between mean time-weighted checklist scores was 0.27 (95 % CI, 0.048-0.49). When measured by global assessment, there was no statistically significant difference between RA and IT participants. These data suggest that the Internet module taught basic principles of management of the opioid-poisoned patient. In this scenario, global assessment and checklist assessment may not measure the same proficiencies. These encouraging results are not sufficient to show that this Internet tool improves clinical performance. We should assess the impact of the Internet module on performance in a true clinical environment.

Influences of Local Sea-Surface Temperatures and Large-scale Dynamics on Monthly Precipitation Inferred from Two 10-year GCM-Simulations

NASA Technical Reports Server (NTRS)

Sud, Y. C.; Walker, G. K.; Zhou, Y.; Lau, W. K.-M.

2007-01-01

Two parallel sets of 10-year long: January 1, 1982 to December 31, 1991, simulations were made with the finite volume General Circulation Model (fvGCM) in which the model integrations were forced with prescribed sea-surface temperature fields (SSTs) available as two separate SST-datasets. One dataset contained naturally varying monthly SSTs for the chosen period, and the oth& had the 12-monthly mean SSTs for the same period. Plots of evaporation, precipitation, and atmosphere-column moisture convergence, binned by l C SST intervals show that except for the tropics, the precipitation is more strongly constrained by large-scale dynamics as opposed to local SST. Binning data by SST naturally provided an ensemble average of data contributed from disparate locations with same SST; such averages could be expected to mitigate all location related influences. However, the plots revealed: i) evaporation, vertical velocity, and precipitation are very robust and remarkably similar for each of the two simulations and even for the data from 1987-ENSO-year simulation; ii) while the evaporation increased monotonically with SST up to about 27 C, the precipitation did not; iii) precipitation correlated much better with the column vertical velocity as opposed to SST suggesting that the influence of dynamical circulation including non-local SSTs is stronger than local-SSTs. The precipitation fields were doubly binned with respect to SST and boundary-layer mass and/or moisture convergence. The analysis discerned the rate of change of precipitation with local SST as a sum of partial derivative of precipitation with local SST plus partial derivative of precipitation with boundary layer moisture convergence multiplied by the rate of change of boundary-layer moisture convergence with SST (see Eqn. 3 of Section 4.5). This analysis is mathematically rigorous as well as provides a quantitative measure of the influence of local SST on the local precipitation. The results were recast to

Test Results From a Simulated High-Voltage Lunar Power Transmission Line

NASA Technical Reports Server (NTRS)

Birchenough, Arthur; Hervol, David

2008-01-01

The Alternator Test Unit (ATU) in the Lunar Power System Facility (LPSF) located at the NASA Glenn Research Center (GRC) in Cleveland, Ohio was modified to simulate high-voltage transmission capability. The testbed simulated a 1 km transmission cable length from the ATU to the LPSF using resistors and inductors installed between the distribution transformers. Power factor correction circuitry was used to compensate for the reactance of the distribution system to improve the overall power factor. This test demonstrated that a permanent magnet alternator can successfully provide high-frequency ac power to a lunar facility located at a distance.

Test Results from a Simulated High Voltage Lunar Power Transmission Line

NASA Technical Reports Server (NTRS)

Birchenough, Arthur; Hervol, David

2008-01-01

The Alternator Test Unit (ATU) in the Lunar Power System Facility (LPSF) located at the NASA Glenn Research Center (GRC) in Cleveland, OH was modified to simulate high voltage transmission capability. The testbed simulated a 1 km transmission cable length from the ATU to the LPSF using resistors and inductors installed between the distribution transformers. Power factor correction circuitry was used to compensate for the reactance of the distribution system to improve the overall power factor. This test demonstrated that a permanent magnet alternator can successfully provide high frequency AC power to a lunar facility located at a distance.

Finite difference model for aquifer simulation in two dimensions with results of numerical experiments

USGS Publications Warehouse

Trescott, Peter C.; Pinder, George Francis; Larson, S.P.

1976-01-01

The model will simulate ground-water flow in an artesian aquifer, a water-table aquifer, or a combined artesian and water-table aquifer. The aquifer may be heterogeneous and anisotropic and have irregular boundaries. The source term in the flow equation may include well discharge, constant recharge, leakage from confining beds in which the effects of storage are considered, and evapotranspiration as a linear function of depth to water. The theoretical development includes presentation of the appropriate flow equations and derivation of the finite-difference approximations (written for a variable grid). The documentation emphasizes the numerical techniques that can be used for solving the simultaneous equations and describes the results of numerical experiments using these techniques. Of the three numerical techniques available in the model, the strongly implicit procedure, in general, requires less computer time and has fewer numerical difficulties than do the iterative alternating direction implicit procedure and line successive overrelaxation (which includes a two-dimensional correction procedure to accelerate convergence). The documentation includes a flow chart, program listing, an example simulation, and sections on designing an aquifer model and requirements for data input. It illustrates how model results can be presented on the line printer and pen plotters with a program that utilizes the graphical display software available from the Geological Survey Computer Center Division. In addition the model includes options for reading input data from a disk and writing intermediate results on a disk.

Brownfield Action: An Integrated Environmental Science Simulation Experience for Undergraduates.

ERIC Educational Resources Information Center

Kelsey, Ryan

This paper presents the results of three years of development and evaluation of a CD-ROM/Web hybrid simulation known as Brownfield Action for an introductory environmental science course at an independent college for women in the northeastern United States. Brownfield Action is a simulation that provides a learning environment for developing the…

Structured water in polyelectrolyte dendrimers: Understanding small angle neutron scattering results through atomistic simulation

NASA Astrophysics Data System (ADS)

Wu, Bin; Kerkeni, Boutheïna; Egami, Takeshi; Do, Changwoo; Liu, Yun; Wang, Yongmei; Porcar, Lionel; Hong, Kunlun; Smith, Sean C.; Liu, Emily L.; Smith, Gregory S.; Chen, Wei-Ren

2012-04-01

Based on atomistic molecular dynamics (MD) simulations, the small angle neutron scattering (SANS) intensity behavior of a single generation-4 polyelectrolyte polyamidoamine starburst dendrimer is investigated at different levels of molecular protonation. The SANS form factor, P(Q), and Debye autocorrelation function, γ(r), are calculated from the equilibrium MD trajectory based on a mathematical approach proposed in this work. The consistency found in comparison against previously published experimental findings (W.-R. Chen, L. Porcar, Y. Liu, P. D. Butler, and L. J. Magid, Macromolecules 40, 5887 (2007)) leads to a link between the neutron scattering experiment and MD computation, and fresh perspectives. The simulations enable scattering calculations of not only the hydrocarbons but also the contribution from the scattering length density fluctuations caused by structured, confined water within the dendrimer. Based on our computational results, we explore the validity of using radius of gyration RG for microstructure characterization of a polyelectrolyte dendrimer from the scattering perspective.

Suppression tuning of distortion-product otoacoustic emissions: Results from cochlear mechanics simulation

PubMed Central

Liu, Yi-Wen; Neely, Stephen T.

2013-01-01

This paper presents the results of simulating the acoustic suppression of distortion-product otoacoustic emissions (DPOAEs) from a computer model of cochlear mechanics. A tone suppressor was introduced, causing the DPOAE level to decrease, and the decrement was plotted against an increasing suppressor level. Suppression threshold was estimated from the resulting suppression growth functions (SGFs), and suppression tuning curves (STCs) were obtained by plotting the suppression threshold as a function of suppressor frequency. Results show that the slope of SGFs is generally higher for low-frequency suppressors than high-frequency suppressors, resembling those obtained from normal hearing human ears. By comparing responses of normal (100%) vs reduced (50%) outer-hair-cell sensitivities, the model predicts that the tip-to-tail difference of the STCs correlates well with that of intra-cochlear iso-displacement tuning curves. The correlation is poorer, however, between the sharpness of the STCs and that of the intra-cochlear tuning curves. These results agree qualitatively with what was recently reported from normal-hearing and hearing-impaired human subjects, and examination of intra-cochlear model responses can provide the needed insight regarding the interpretation of DPOAE STCs obtained in individual ears. PMID:23363112

DEVELOPMENT AND ANALYSIS OF AIR QUALITY MODELING SIMULATIONS FOR HAZARDOUS AIR POLLUTANTS

EPA Science Inventory

The concentrations of five hazardous air pollutants were simulated using the Community Multi Scale Air Quality (CMAQ) modeling system. Annual simulations were performed over the continental United States for the entire year of 2001 to support human exposure estimates. Results a...

Evaluating best educational practices, student satisfaction, and self-confidence in simulation: A descriptive study.

PubMed

Zapko, Karen A; Ferranto, Mary Lou Gemma; Blasiman, Rachael; Shelestak, Debra

2018-01-01

The National League for Nursing (NLN) has endorsed simulation as a necessary teaching approach to prepare students for the demanding role of professional nursing. Questions arise about the suitability of simulation experiences to educate students. Empirical support for the effect of simulation on patient outcomes is sparse. Most studies on simulation report only anecdotal results rather than data obtained using evaluative tools. The aim of this study was to examine student perception of best educational practices in simulation and to evaluate their satisfaction and self-confidence in simulation. This study was a descriptive study designed to explore students' perceptions of the simulation experience over a two-year period. Using the Jeffries framework, a Simulation Day was designed consisting of serial patient simulations using high and medium fidelity simulators and live patient actors. The setting for the study was a regional campus of a large Midwestern Research 2 university. The convenience sample consisted of 199 participants and included sophomore, junior, and senior nursing students enrolled in the baccalaureate nursing program. The Simulation Days consisted of serial patient simulations using high and medium fidelity simulators and live patient actors. Participants rotated through four scenarios that corresponded to their level in the nursing program. Data was collected in two consecutive years. Participants completed both the Educational Practices Questionnaire (Student Version) and the Student Satisfaction and Self-Confidence in Learning Scale. Results provide strong support for using serial simulation as a learning tool. Students were satisfied with the experience, felt confident in their performance, and felt the simulations were based on sound educational practices and were important for learning. Serial simulations and having students experience simulations more than once in consecutive years is a valuable method of clinical instruction. When

[Simulation training in surgical education - application of virtual reality laparoscopic simulators in a surgical skills course].

PubMed

Lehmann, K S; Gröne, J; Lauscher, J C; Ritz, J-P; Holmer, C; Pohlen, U; Buhr, H-J

2012-04-01

Training and simulation are gaining importance in surgical education. Today, virtual reality surgery simulators provide sophisticated laparoscopic training scenarios and offer detailed assessment methods. This also makes simulators interesting for the application in surgical skills courses. The aim of the current study was to assess the suitability of a virtual surgery simulator for training and assessment in an established surgical training course. The study was conducted during the annual "Practical Course for Visceral Surgery" (Warnemuende, Germany). 36 of 108 course participants were assigned at random for the study. Training was conducted in 15 sessions over 5 days with 4 identical virtual surgery simulators (LapSim) and 2 standardised training tasks. The simulator measured 16 individual parameters and calculated 2 scores. Questionnaires were used to assess the test persons' laparoscopic experience, their training situation and the acceptance of the simulator training. Data were analysed with non-parametric tests. A subgroup analysis for laparoscopic experience was conducted in order to assess the simulator's construct validity and assessment capabilities. Median age was 32 (27 - 41) years; median professional experience was 3 (1 - 11) years. Typical laparoscopic learning curves with initial significant improvements and a subsequent plateau phase were measured over 5 days. The individual training sessions exhibited a rhythmic variability in the training results. A shorter night's sleep led to a marked drop in performance. The participants' different experience levels could clearly be discriminated ( ≤ 20 vs. > 20 laparoscopic operations; p ≤ 0.001). The questionnaire showed that the majority of the participants had limited training opportunities in their hospitals. The simulator training was very well accepted. However, the participants severely misjudged the real costs of the simulators that were used. The learning curve on the

Detached Eddy Simulation Results for a Space Launch System Configuration at Liftoff Conditions and Comparison with Experiment

NASA Technical Reports Server (NTRS)

Krist, Steven E.; Ghaffari, Farhad

2015-01-01

Computational simulations for a Space Launch System configuration at liftoff conditions for incidence angles from 0 to 90 degrees were conducted in order to generate integrated force and moment data and longitudinal lineloads. While the integrated force and moment coefficients can be obtained from wind tunnel testing, computational analyses are indispensable in obtaining the extensive amount of surface information required to generate proper lineloads. However, beyond an incidence angle of about 15 degrees, the effects of massive flow separation on the leeward pressure field is not well captured with state of the art Reynolds Averaged Navier-Stokes methods, necessitating the employment of a Detached Eddy Simulation method. Results from these simulations are compared to the liftoff force and moment database and surface pressure data derived from a test in the NASA Langley 14- by 22-Foot Subsonic Wind Tunnel.

Control of Warm Compression Stations Using Model Predictive Control: Simulation and Experimental Results

NASA Astrophysics Data System (ADS)

Bonne, F.; Alamir, M.; Bonnay, P.

2017-02-01

This paper deals with multivariable constrained model predictive control for Warm Compression Stations (WCS). WCSs are subject to numerous constraints (limits on pressures, actuators) that need to be satisfied using appropriate algorithms. The strategy is to replace all the PID loops controlling the WCS with an optimally designed model-based multivariable loop. This new strategy leads to high stability and fast disturbance rejection such as those induced by a turbine or a compressor stop, a key-aspect in the case of large scale cryogenic refrigeration. The proposed control scheme can be used to achieve precise control of pressures in normal operation or to avoid reaching stopping criteria (such as excessive pressures) under high disturbances (such as a pulsed heat load expected to take place in future fusion reactors, expected in the cryogenic cooling systems of the International Thermonuclear Experimental Reactor ITER or the Japan Torus-60 Super Advanced fusion experiment JT-60SA). The paper details the simulator used to validate this new control scheme and the associated simulation results on the SBTs WCS. This work is partially supported through the French National Research Agency (ANR), task agreement ANR-13-SEED-0005.

Development of space simulation / net-laboratory system

NASA Astrophysics Data System (ADS)

Usui, H.; Matsumoto, H.; Ogino, T.; Fujimoto, M.; Omura, Y.; Okada, M.; Ueda, H. O.; Murata, T.; Kamide, Y.; Shinagawa, H.; Watanabe, S.; Machida, S.; Hada, T.

A research project for the development of space simulation / net-laboratory system was approved by Japan Science and Technology Corporation (JST) in the category of Research and Development for Applying Advanced Computational Science and Technology(ACT-JST) in 2000. This research project, which continues for three years, is a collaboration with an astrophysical simulation group as well as other space simulation groups which use MHD and hybrid models. In this project, we develop a proto type of unique simulation system which enables us to perform simulation runs by providing or selecting plasma parameters through Web-based interface on the internet. We are also developing an on-line database system for space simulation from which we will be able to search and extract various information such as simulation method and program, manuals, and typical simulation results in graphic or ascii format. This unique system will help the simulation beginners to start simulation study without much difficulty or effort, and contribute to the promotion of simulation studies in the STP field. In this presentation, we will report the overview and the current status of the project.

Soil-test N recommendations augmented with PEST-optimized RZWQM simulations

USGS Publications Warehouse

Malone, R.W.; Jaynes, D.B.; Ma, Liwang; Nolan, B.T.; Meek, D.W.; Karlen, D.L.

2010-01-01

Improved understanding of year-to-year late-spring soil nitrate test (LSNT) variability could help make it more attractive to producers. We test the ability of the Root Zone Water Quality Model (RZWQM) to simulate watershed-scale variability due to the LSNT, and we use the optimized model to simulate long-term field N dynamics under related conditions. Autoregressive techniques and the automatic parameter calibration program PEST were used to show that RZWQM simulates significantly lower nitrate concentration in discharge from LSNT treatments compared with areas receiving fall N fertilizer applications within the tile-drained Walnut Creek, Iowa, watershed (>5 mg N L-1 difference for the third year of the treatment, 1999). This result is similar to field-measured data from a paired watershed experiment. A statistical model we developed using RZWQM simulations from 1970 to 2005 shows that early-season precipitation and early-season temperature account for 90% of the interannual variation in LSNT-based fertilizer N rates. Long-term simulations with similar average N application rates for corn (Zea mays L.) (151 kg N ha-1) show annual average N loss in tile flow of 20.4, 22.2, and 27.3 kg N ha -1 for LSNT, single spring, and single fall N applications. These results suggest that (i) RZWQM is a promising tool to accurately estimate the water quality effects of LSNT; (ii) the majority of N loss difference between LSNT and fall applications is because more N remains in the root zone for crop uptake; and (iii) year-to-year LSNT-based N rate differences are mainly due to variation in early-season precipitation and temperature. Copyright ?? 2010 by the American Society of Agronomy, Crop Science Society of America, and Soil Science Society of America. All rights reserved.

First-Year Results of an Obesity Prevention Program at The Dow Chemical Company

PubMed Central

Goetzel, Ron Z.; Baker, Kristin M.; Short, Meghan E.; Pei, Xiaofei; Ozminkowski, Ronald J.; Wang, Shaohung; Bowen, Jennie D.; Roemer, Enid C.; Craun, Beth A.; Tully, Karen J.; Baase, Catherine M.

2010-01-01

Objective To examine first-year results from a workplace environmental obesity prevention program at The Dow Chemical Company. Methods A quasi-experimental cohort study was conducted among employees at nine treatment worksites (n=8,013) who received environmental weight management interventions and three control worksites (n=2,269). Changes in employees’ weight, body mass index (BMI), and other health risks were examined using chi-square and t-tests. Results After one year, a modest treatment effect was observed for weight and BMI largely because the control group subjects gained weight; however, no effect was observed for overweight and obesity prevalence. Other risk factors (tobacco use, high blood pressure, and systolic and diastolic blood pressure values) decreased significantly, although blood glucose (high risk prevalence and values) increased. Conclusions Environmental changes to the workplace can achieve modest improvements in employees’ health risks, including weight and BMI measures, in one year. PMID:19209033

Simulation of traffic control signal systems

NASA Technical Reports Server (NTRS)

Connolly, P. J.; Concannon, P. A.; Ricci, R. C.

1974-01-01

In recent years there has been considerable interest in the development and testing of control strategies for networks of urban traffic signal systems by simulation. Simulation is an inexpensive and timely method for evaluating the effect of these traffic control strategies since traffic phenomena are too complex to be defined by analytical models and since a controlled experiment may be hazardous, expensive, and slow in producing meaningful results. This paper describes the application of an urban traffic corridor program, to evaluate the effectiveness of different traffic control strategies for the Massachusetts Avenue TOPICS Project.

Simulation of Columbia River Floods in the Hanford Reach

DOE Office of Scientific and Technical Information (OSTI.GOV)

Waichler, Scott R.; Serkowski, John A.; Perkins, William A.

Columbia River water elevations and flows in the Hanford Reach affect the environment and facilities along the shoreline, including movement of contaminants in groundwater, fish habitat, and infrastructure subject to flooding. This report describes the hydraulic simulation of hypothetical flood flows using the best available topographic and bathymetric data for the Hanford Reach and the Modular Aquatic Simulation System in 1 Dimension (MASS1) hydrodynamic model. The MASS1 model of the Hanford Reach was previously calibrated to field measurements of water surface elevations. The current model setup can be used for other studies of flow, water levels, and temperature in themore » Reach. The existing MASS1 channel geometry and roughness and other model configuration inputs for the Hanford Reach were used for this study, and previous calibration and validation results for the model are reprinted here for reference. The flood flows for this study were simulated by setting constant flow rates obtained from the U.S. Army Corps of Engineers (USACE) for the Columbia, Snake, and Yakima Rivers, and a constant water level at McNary Dam, and then running the model to steady state. The discharge levels simulated were all low-probability events; for example, a 100-year flood is one that would occur on average every 100 years, or put another way, in any given year there is a 1% chance that a discharge of that level or higher will occur. The simulated floods and their corresponding Columbia River discharges were 100-year (445,000 cfs), 500-year (520,000 cfs), and the USACE-defined Standard Project Flood (960,000 cfs). The resulting water levels from the steady-state floods can be viewed as “worst case” outcomes for the respective discharge levels. The MASS1 output for water surface elevations was converted to the North American Vertical Datum of 1988 and projected across the channel and land surface to enable mapping of the floodplain for each scenario. Floodplain maps show

Sensitivity of simulated Martian atmospheric temperature to prescribed dust opacity distribution: Comparison of model results with reconstructed data from Mars Exploration Rover missions

NASA Astrophysics Data System (ADS)

Natarajan, Murali; Dwyer Cianciolo, Alicia; Fairlie, T. Duncan; Richardson, Mark I.; McConnochie, Timothy H.

2015-11-01

We use the Mars Weather Research and Forecasting (MarsWRF) general circulation model to simulate the atmospheric structure corresponding to the landing location and time of the Mars Exploration Rovers (MER) Spirit (A) and Opportunity (B) in 2004. The multiscale capability of MarsWRF facilitates high-resolution nested model runs centered near the landing site of each of the rovers. Dust opacity distributions based on measurements by Thermal Emission Spectrometer (TES) aboard the Mars Global Surveyor spacecraft, and those from an old version of the Mars Climate Database (MCD v3.1 released in 2001) are used to study the sensitivity of the model temperature profile to variations in the dust prescription. The reconstructed entry, descent, and landing (EDL) data from the rover missions are used for comparisons. We show that the model using dust opacity from TES limb and nadir data for the year of MER EDL, Mars Year 26 (MY26), yields temperature profiles in closer agreement with the reconstructed data than the prelaunch EDL simulations and models using other dust opacity specifications. The temperature at 100 Pa from the model (MY26) and the reconstruction are within 5°K. These results highlight the role of vertical dust opacity distribution in determining the atmospheric thermal structure. Similar studies involving data from past missions and models will be useful in understanding the extent to which atmospheric variability is captured by the models and in developing realistic preflight characterization required for future lander missions to Mars.

Adjustment and validation of a simulation tool for CSP plants based on parabolic trough technology

NASA Astrophysics Data System (ADS)

García-Barberena, Javier; Ubani, Nora

2016-05-01

The present work presents the validation process carried out for a simulation tool especially designed for the energy yield assessment of concentrating solar plants based on parabolic through (PT) technology. The validation has been carried out by comparing the model estimations with real data collected from a commercial CSP plant. In order to adjust the model parameters used for the simulation, 12 different days were selected among one-year of operational data measured at the real plant. The 12 days were simulated and the estimations compared with the measured data, focusing on the most important variables from the simulation point of view: temperatures, pressures and mass flow of the solar field, gross power, parasitic power, and net power delivered by the plant. Based on these 12 days, the key parameters for simulating the model were properly fixed and the simulation of a whole year performed. The results obtained for a complete year simulation showed very good agreement for the gross and net electric total production. The estimations for these magnitudes show a 1.47% and 2.02% BIAS respectively. The results proved that the simulation software describes with great accuracy the real operation of the power plant and correctly reproduces its transient behavior.

Lahar hazard assessment in the southern drainage system of Cotopaxi volcano, Ecuador: Results from multiscale lahar simulations

NASA Astrophysics Data System (ADS)

Pistolesi, Marco; Cioni, Raffaello; Rosi, Mauro; Aguilera, Eduardo

2014-02-01

The ice-capped Cotopaxi volcano is known worldwide for the large-scale, catastrophic lahars that have occurred in connection with historical explosive eruptions. The most recent large-scale lahar event occurred in 1877 when scoria flows partially melted ice and snow of the summit glacier, generating debris flows that severely impacted all the river valleys originating from the volcano. The 1877 lahars have been considered in the recent years as a maximum expected event to define the hazard associated to lahar generation at Cotopaxi. Conversely, recent field-based studies have shown that such debris flows have occurred several times during the last 800 years of activity at Cotopaxi, and that the scale of lahars has been variable, including events much larger than that of 1877. Despite a rapid retreat of the summit ice cap over the past century, in fact, there are no data clearly suggesting that future events will be smaller than those observed in the deposits of the last 800 years of activity. In addition, geological field data prove that the lahar triggering mechanism also has to be considered as a key input parameter and, under appropriate eruptive mechanisms, a hazard scenario of a lahar with a volume 3-times larger than the 1877 event is likely. In order to analyze the impact scenarios in the southern drainage system of the volcano, simulations of inundation areas were performed with a semi-empirical model (LAHARZ), using input parameters including variable water volume. Results indicate that a lahar 3-times larger than the 1877 event would invade much wider areas than those flooded by the 1877 lahars along the southern valley system, eventually impacting highly-urbanized areas such as the city of Latacunga.

Dynamic Evaluation of Two Decades of CMAQ Simulations ...

EPA Pesticide Factsheets

This presentation focuses on the dynamic evaluation of the CMAQ model over the continental United States using multi-decadal simulations for the period from 1990 to 2010 to examine how well the changes in observed ozone air quality induced by variations in meteorology and/or emissions are simulated by the model. We applied spectral decomposition of the ozone time-series using the KZ filter to assess the variations in the strengths of synoptic (weather-induced variations) and baseline (long-term variation) forcings, embedded in the simulated and observed concentrations. The results reveal that CMAQ captured the year-to-year variability (more so in the later years than the earlier years) and the synoptic forcing in accordance with what the observations are showing. The National Exposure Research Laboratory (NERL) Computational Exposure Division (CED) develops and evaluates data, decision-support tools, and models to be applied to media-specific or receptor-specific problem areas. CED uses modeling-based approaches to characterize exposures, evaluate fate and transport, and support environmental diagnostics/forensics with input from multiple data sources. It also develops media- and receptor-specific models, process models, and decision support tools for use both within and outside of EPA.

Electron backscattering simulation in Geant4

NASA Astrophysics Data System (ADS)

Dondero, Paolo; Mantero, Alfonso; Ivanchencko, Vladimir; Lotti, Simone; Mineo, Teresa; Fioretti, Valentina

2018-06-01

The backscattering of electrons is a key phenomenon in several physics applications which range from medical therapy to space including AREMBES, the new ESA simulation framework for radiation background effects. The importance of properly reproducing this complex interaction has grown considerably in the last years and the Geant4 Monte Carlo simulation toolkit, recently upgraded to the version 10.3, is able to comply with the AREMBES requirements in a wide energy range. In this study a validation of the electron Geant4 backscattering models is performed with respect to several experimental data. In addition a selection of the most recent validation results on the electron scattering processes is also presented. Results of our analysis show a good agreement between simulations and data from several experiments, confirming the Geant4 electron backscattering models to be robust and reliable up to a few tens of electronvolts.

Deferred rotation harvests in central Appalachia: 20- and 25-year results

Treesearch

Melissa Thomas-Van Gundy; Thomas M. Schuler

2008-01-01

In deferment harvest, two distinct age classes are created and the residual trees remain after establishment of the second cohort. The 20- or 25-year preliminary results from four deferment areas are described. For each area, volume and growth in the residual trees and new cohort, and structure and composition of the new cohort are presented. We also address whether...

Yarding cost for the Koller K300 cable yarder: results from field trials and simulations

Treesearch

Neil K. Huyler; Chris B. LeDoux

1997-01-01

This paper describes results from field studies and simulation that can be used to estimate the yarding cost for the Koller K300 cable yarder. Yarding costs can be estimated for clearcuts and light and heavy thinnings in eastern hardwoods. Yarding costs can be estimated with a handheld calculator, or the data can be incorporated into stump-to-mill desktop PC and...

Comparison of preliminary results from Airborne Aster Simulator (AAS) with TIMS data

NASA Technical Reports Server (NTRS)

Kannari, Yoshiaki; Mills, Franklin; Watanabe, Hiroshi; Ezaka, Teruya; Narita, Tatsuhiko; Chang, Sheng-Huei

1992-01-01

The Japanese Advanced Spaceborne Thermal Emission and Reflection radiometer (ASTER), being developed for a NASA EOS-A satellite, will have 3 VNIR, 6 SWIR, and 5 TIR (8-12 micron) bands. An Airborne ASTER Simulator (AAS) was developed for Japan Resources Observation System Organization (JAROS) by the Geophysical Environmental Research Group (GER) Corp. to research surface temperature and emission features in the MWIR/TIR, to simulate ASTER's TIR bands, and to study further possibility of MWIR/TIR bands. ASTER Simulator has 1 VNIR, 3 MWIR (3-5 microns), and 20 (currently 24) TIR bands. Data was collected over 3 sites - Cuprite, Nevada; Long Valley/Mono Lake, California; and Death Valley, California - with simultaneous ground truth measurements. Preliminary data collected by AAS for Cuprite, Nevada is presented and AAS data is compared with Thermal Infrared Multispectral Scanner (TIMS) data.

STREAM CHANNELS OF THE UPPER SAN PEDRO BASIN WITH PERCENT DIFFERENCE BETWEEN RESULTS FROM TWO SWAT SIMULATIONS

EPA Science Inventory

Stream channels of the Upper San Pedro with percent difference between results from two SWAT simulations run through AGWA: one using the 1973 NALC landcover for model parameterization, and the other using the 1997 NALC landcover.

Space telescope neutral buoyancy simulations: The first two years

NASA Technical Reports Server (NTRS)

Sanders, F. G.

1982-01-01

Neutral Buoyancy simulations which were conducted to validate the crew systems interface as it relates to space telescope on-orbit maintenance and contingency operations is discussed. The initial concept validation tests using low fidelity mockups is described. The entire spectrum of proposed space telescope refurbishment and selected contingencies using upgraded mockups which reflect flight hardware are reported. Findings which may be applicable to future efforts of a similar nature are presented.

Results from Numerical General Relativity

NASA Technical Reports Server (NTRS)

Baker, John G.

2011-01-01

For several years numerical simulations have been revealing the details of general relativity's predictions for the dynamical interactions of merging black holes. I will review what has been learned of the rich phenomenology of these mergers and the resulting gravitational wave signatures. These wave forms provide a potentially observable record of the powerful astronomical events, a central target of gravitational wave astronomy. Asymmetric radiation can produce a thrust on the system which may accelerate the single black hole resulting from the merger to high relative velocity.

[Primary prevention of cardiovascular diseases: long term results of five year long preventive intervention in 12-year old boys (ten year prospective study)].

PubMed

Rozanov, V B; Aleksandov, A A; Shugaeva, E N; Perova, N V; Maslennikova, G Ia; Smirnova, S G; Olfer'ev, A M

2007-01-01

In a longitudinal cohort (prevention group, n=213, comparison group, n=163) of 10-year prospective follow-up we addressed efficacy of 5-year-long multifactor preventive intervention, conducted in a sample of population of 12 year old boys. Preventive intervention was carried out both at populational level and among persons with risk factors of development of cardiovascular diseases with the use of group, individual, and partly family approaches, and was directed at rationalization of nutrition, elevation of physical activity and prevention of harmful habits. During first 3 years of prevention we succeeded to achieve stable statistically significant lowering of mean levels of total cholesterol, low density lipoprotein cholesterol, triglycerides, and atherogeneity index, as well as to affect fatty component of body mass (skinfold thickness). Long term effect of 5-year long preventive intervention manifested as significantly lower level of systolic blood pressure, lower prevalence of low levels of high density lipoprotein cholesterol, smaller increment of low density lipoprotein cholesterol and index of atherogeneity in the prevention group. These results evidence that prevention of main factors of risk of development of cardiovascular diseases (obesity, arterial hypertension, disorders of lipid composition of the blood, and low physical activity) in child and adolescent age in the period of active growth and development is feasible, effective, safe and is able to lead to decrease of levels of these factors in adults, but should last uninterruptedly until formation of stable habits of healthy life style.

Accelerating 3D Hall MHD Magnetosphere Simulations with Graphics Processing Units

NASA Astrophysics Data System (ADS)

Bard, C.; Dorelli, J.

2017-12-01

The resolution required to simulate planetary magnetospheres with Hall magnetohydrodynamics result in program sizes approaching several hundred million grid cells. These would take years to run on a single computational core and require hundreds or thousands of computational cores to complete in a reasonable time. However, this requires access to the largest supercomputers. Graphics processing units (GPUs) provide a viable alternative: one GPU can do the work of roughly 100 cores, bringing Hall MHD simulations of Ganymede within reach of modest GPU clusters ( 8 GPUs). We report our progress in developing a GPU-accelerated, three-dimensional Hall magnetohydrodynamic code and present Hall MHD simulation results for both Ganymede (run on 8 GPUs) and Mercury (56 GPUs). We benchmark our Ganymede simulation with previous results for the Galileo G8 flyby, namely that adding the Hall term to ideal MHD simulations changes the global convection pattern within the magnetosphere. Additionally, we present new results for the G1 flyby as well as initial results from Hall MHD simulations of Mercury and compare them with the corresponding ideal MHD runs.

Analysis of formation pressure test results in the Mount Elbert methane hydrate reservoir through numerical simulation

USGS Publications Warehouse

Kurihara, M.; Sato, A.; Funatsu, K.; Ouchi, H.; Masuda, Y.; Narita, H.; Collett, T.S.

2011-01-01

Targeting the methane hydrate (MH) bearing units C and D at the Mount Elbert prospect on the Alaska North Slope, four MDT (Modular Dynamic Formation Tester) tests were conducted in February 2007. The C2 MDT test was selected for history matching simulation in the MH Simulator Code Comparison Study. Through history matching simulation, the physical and chemical properties of the unit C were adjusted, which suggested the most likely reservoir properties of this unit. Based on these properties thus tuned, the numerical models replicating "Mount Elbert C2 zone like reservoir" "PBU L-Pad like reservoir" and "PBU L-Pad down dip like reservoir" were constructed. The long term production performances of wells in these reservoirs were then forecasted assuming the MH dissociation and production by the methods of depressurization, combination of depressurization and wellbore heating, and hot water huff and puff. The predicted cumulative gas production ranges from 2.16??106m3/well to 8.22??108m3/well depending mainly on the initial temperature of the reservoir and on the production method.This paper describes the details of modeling and history matching simulation. This paper also presents the results of the examinations on the effects of reservoir properties on MH dissociation and production performances under the application of the depressurization and thermal methods. ?? 2010 Elsevier Ltd.

First Results From the Ionospheric Extension of WACCM-X During the Deep Solar Minimum Year of 2008

NASA Astrophysics Data System (ADS)

Liu, Jing; Liu, Hanli; Wang, Wenbin; Burns, Alan G.; Wu, Qian; Gan, Quan; Solomon, Stanley C.; Marsh, Daniel R.; Qian, Liying; Lu, Gang; Pedatella, Nicholas M.; McInerney, Joe M.; Russell, James M.; Schreiner, William S.

2018-02-01

New ionosphere and electrodynamics modules have been incorporated in the thermosphere and ionosphere eXtension of the Whole Atmosphere Community Climate Model (WACCM-X), in order to self-consistently simulate the coupled atmosphere-ionosphere system. The first specified dynamics WACCM-X v.2.0 results are compared with several data sets, and with the Thermosphere-Ionosphere-Electrodynamics General Circulation Model (TIE-GCM), during the deep solar minimum year. Comparisons with Thermosphere Ionosphere Mesosphere Energetics and Dynamics satellite of temperature and zonal wind in the lower thermosphere show that WACCM-X reproduces the seasonal variability of tides remarkably well, including the migrating diurnal and semidiurnal components and the nonmigrating diurnal eastward propagating zonal wavenumber 3 component. There is overall agreement between WACCM-X, TIE-GCM, and vertical drifts observed by the Communication/Navigation Outage Forecast System (C/NOFS) satellite over the magnetic equator, but apparent discrepancies also exist. Both model results are dominated by diurnal variations, while C/NOFS observed vertical plasma drifts exhibit strong temporal variations. The climatological features of ionospheric peak densities and heights (NmF2 and hmF2) from WACCM-X are in general agreement with the results derived from Constellation Observing System for Meteorology, Ionosphere and Climate (COSMIC) data, although the WACCM-X predicted NmF2 values are smaller, and the equatorial ionization anomaly crests are closer to the magnetic equator compared to COSMIC and ionosonde observations. This may result from the excessive mixing in the lower thermosphere due to the gravity wave parameterization. These data-model comparisons demonstrate that WACCM-X can capture the dynamic behavior of the coupled atmosphere and ionosphere in a climatological sense.

Simulation of the water-table altitude in the Biscayne Aquifer, southern Dade County, Florida, water years 1945-89

USGS Publications Warehouse

Merritt, M.L.

1995-01-01

A digital model of the flow system in the highly permeable surficial aquifer of southern Dade County, Florida, was constructed for the purposes of better understanding processes that influence the flow system and of supporting the construction of a subregional model of the transport of brackish water from a flowing artesian well. Problems that needed resolution in this endeavor included the development of methods to represent the influence of flowing surface water in seasonally inundated wetlands and the influence of a network of controlled canals developed in stages during the simulation time period (water years 1945-89). An additional problem was the general lack of natural aquifer boundaries near the boundaries of the study area. The model construction was based on a conceptual description of the Biscayne aquifer developed from the results of previous U.S. Geological Survey investigations. Modifications were made to an existing three- dimensional finite-difference simulator of ground- water flow to enable an upper layer of the grid to represent seasonally occurring overland sheetflow in a series of transient simulations of water levels from 1945 to 1989. A rewetting procedure was developed for the simulator that permitted resaturation of cells in this layer when the wet season recurred. An "equivalent hydraulic conductivity" coefficient was assigned to the overland flow layer that was analogous, subject to various approximations, to the use of the Manning equation. The surficial semiconfining peat and marl layers, levees, canals, and control structures were also represented as part of the model grid with the appropriate choices of hydraulic coefficient values. For most of the Biscayne aquifer grid cells, the value assigned to hydraulic conductivity for model calibration was 30,000 feet per day and the value assigned to porosity was 20 percent. Boundary conditions were specified near data sites having long-term records of surface-water stages or water

First results from the IllustrisTNG simulations: matter and galaxy clustering

NASA Astrophysics Data System (ADS)

Springel, Volker; Pakmor, Rüdiger; Pillepich, Annalisa; Weinberger, Rainer; Nelson, Dylan; Hernquist, Lars; Vogelsberger, Mark; Genel, Shy; Torrey, Paul; Marinacci, Federico; Naiman, Jill

2018-03-01

Hydrodynamical simulations of galaxy formation have now reached sufficient volume to make precision predictions for clustering on cosmologically relevant scales. Here, we use our new IllustrisTNG simulations to study the non-linear correlation functions and power spectra of baryons, dark matter, galaxies, and haloes over an exceptionally large range of scales. We find that baryonic effects increase the clustering of dark matter on small scales and damp the total matter power spectrum on scales up to k ˜ 10 h Mpc-1 by 20 per cent. The non-linear two-point correlation function of the stellar mass is close to a power-law over a wide range of scales and approximately invariant in time from very high redshift to the present. The two-point correlation function of the simulated galaxies agrees well with Sloan Digital Sky Survey at its mean redshift z ≃ 0.1, both as a function of stellar mass and when split according to galaxy colour, apart from a mild excess in the clustering of red galaxies in the stellar mass range of109-1010 h-2 M⊙. Given this agreement, the TNG simulations can make valuable theoretical predictions for the clustering bias of different galaxy samples. We find that the clustering length of the galaxy autocorrelation function depends strongly on stellar mass and redshift. Its power-law slope γ is nearly invariant with stellar mass, but declines from γ ˜ 1.8 at redshift z = 0 to γ ˜ 1.6 at redshift z ˜ 1, beyond which the slope steepens again. We detect significant scale dependences in the bias of different observational tracers of large-scale structure, extending well into the range of the baryonic acoustic oscillations and causing nominal (yet fortunately correctable) shifts of the acoustic peaks of around ˜ 5 per cent.

Hamiltonian and potentials in derivative pricing models: exact results and lattice simulations

NASA Astrophysics Data System (ADS)

Baaquie, Belal E.; Corianò, Claudio; Srikant, Marakani

2004-03-01

The pricing of options, warrants and other derivative securities is one of the great success of financial economics. These financial products can be modeled and simulated using quantum mechanical instruments based on a Hamiltonian formulation. We show here some applications of these methods for various potentials, which we have simulated via lattice Langevin and Monte Carlo algorithms, to the pricing of options. We focus on barrier or path dependent options, showing in some detail the computational strategies involved.

Real time digital propulsion system simulation for manned flight simulators

NASA Technical Reports Server (NTRS)

Mihaloew, J. R.; Hart, C. E.

1978-01-01

A real time digital simulation of a STOL propulsion system was developed which generates significant dynamics and internal variables needed to evaluate system performance and aircraft interactions using manned flight simulators. The simulation ran at a real-to-execution time ratio of 8.8. The model was used in a piloted NASA flight simulator program to evaluate the simulation technique and the propulsion system digital control. The simulation is described and results shown. Limited results of the flight simulation program are also presented.

Northern Idaho ponderosa racial variation study - 50-year results

Treesearch

R. J. Steinhoff

1970-01-01

Ponderosa pine trees from 19 geographic sources planted on a test area in northern Idaho have been measured 12, 20, 40, and 50 years after outplanting. From the 12th through the 50th years after outplanting, trees from one nonlocal source have been tallest. Trees from the local source now rank second in height, having risen from sixth during the last 10 years. In...

Building America House Simulation Protocols

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hendron, Robert; Engebrecht, Cheryn

2010-09-01

The House Simulation Protocol document was developed to track and manage progress toward Building America's multi-year, average whole-building energy reduction research goals for new construction and existing homes, using a consistent analytical reference point. This report summarizes the guidelines for developing and reporting these analytical results in a consistent and meaningful manner for all home energy uses using standard operating conditions.

Does the effect of one-day simulation team training in obstetric emergencies decline within one year? A post-hoc analysis of a multicentre cluster randomised controlled trial.

PubMed

van de Ven, J; Fransen, A F; Schuit, E; van Runnard Heimel, P J; Mol, B W; Oei, S G

2017-09-01

Does the effect of one-day simulation team training in obstetric emergencies decline within one year? A post-hoc analysis of a multicentre cluster randomised controlled trial. J van de Ven, AF Fransen, E Schuit, PJ van Runnard Heimel, BW Mol, SG Oei OBJECTIVE: To investigate whether the effect of a one-day simulation-based obstetric team training on patient outcome changes over time. Post-hoc analysis of a multicentre, open, randomised controlled trial that evaluated team training in obstetrics (TOSTI study).We studied women with a singleton pregnancy beyond 24 weeks of gestation in 24 obstetric units. Included obstetric units were randomised to either a one-day, multi-professional simulation-based team training focusing on crew resource management in a medical simulation centre (12 units) or to no team training (12 units). We assessed whether outcomes differed between both groups in each of the first four quarters following the team training and compared the effect of team training over quarters. Primary outcome was a composite outcome of low Apgar score, severe postpartum haemorrhage, trauma due to shoulder dystocia, eclampsia and hypoxic-ischemic encephalopathy. During a one year period after the team training the rate of obstetric complications, both on the composite level and the individual component level, did not differ between any of the quarters. For trauma due to shoulder dystocia team training led to a significant decrease in the first quarter (0.06% versus 0.26%, OR 0.19, 95% CI 0.03 to 0.98) but in the subsequent quarters no significant reductions were observed. Similar results were found for invasive treatment for severe postpartum haemorrhage where a significant increase was only seen in the first quarter (0.4% versus 0.03%, OR 19, 95% CI 2.5-147), and not thereafter. The beneficial effect of a one-day, simulation-based, multiprofessional, obstetric team training seems to decline after three months. If team training is further evaluated or

Ocean Wave Simulation Based on Wind Field

PubMed Central

2016-01-01

Ocean wave simulation has a wide range of applications in movies, video games and training systems. Wind force is the main energy resource for generating ocean waves, which are the result of the interaction between wind and the ocean surface. While numerous methods to handle simulating oceans and other fluid phenomena have undergone rapid development during the past years in the field of computer graphic, few of them consider to construct ocean surface height field from the perspective of wind force driving ocean waves. We introduce wind force to the construction of the ocean surface height field through applying wind field data and wind-driven wave particles. Continual and realistic ocean waves result from the overlap of wind-driven wave particles, and a strategy was proposed to control these discrete wave particles and simulate an endless ocean surface. The results showed that the new method is capable of obtaining a realistic ocean scene under the influence of wind fields at real time rates. PMID:26808718

Ocean Wave Simulation Based on Wind Field.

PubMed

Li, Zhongyi; Wang, Hao

2016-01-01

Ocean wave simulation has a wide range of applications in movies, video games and training systems. Wind force is the main energy resource for generating ocean waves, which are the result of the interaction between wind and the ocean surface. While numerous methods to handle simulating oceans and other fluid phenomena have undergone rapid development during the past years in the field of computer graphic, few of them consider to construct ocean surface height field from the perspective of wind force driving ocean waves. We introduce wind force to the construction of the ocean surface height field through applying wind field data and wind-driven wave particles. Continual and realistic ocean waves result from the overlap of wind-driven wave particles, and a strategy was proposed to control these discrete wave particles and simulate an endless ocean surface. The results showed that the new method is capable of obtaining a realistic ocean scene under the influence of wind fields at real time rates.

Results of Medium Seventeen Years' Follow-Up after Laparoscopic Choledochotomy for Ductal Stones.

PubMed

Quaresima, Silvia; Balla, Andrea; Guerrieri, Mario; Lezoche, Giovanni; Campagnacci, Roberto; D'Ambrosio, Giancarlo; Lezoche, Emanuele; Paganini, Alessandro M

2016-01-01

Introduction. In a previously published article the authors reported the long-term follow-up results in 138 consecutive patients with gallstones and common bile duct (CBD) stones who underwent laparoscopic transverse choledochotomy (TC) with T-tube biliary drainage and laparoscopic cholecystectomy (LC). Aim of this study is to evaluate the results at up to 23 years of follow-up in the same series. Methods. One hundred twenty-one patients are the object of the present study. Patients were evaluated by clinical visit, blood assay, and abdominal ultrasound. Symptomatic patients underwent cholangio-MRI, followed by endoscopic retrograde cholangiopancreatography (ERCP) as required. Results. Out of 121 patients, 61 elderly patients died from unrelated causes. Fourteen patients were lost to follow-up. In the 46 remaining patients, ductal stone recurrence occurred in one case (2,1%) successfully managed by ERCP with endoscopic sphincterotomy. At a mean follow-up of 17.1 years no other patients showed signs of bile stasis and no patient showed any imaging evidence of CBD stricture at the site of choledochotomy. Conclusions. Laparoscopic transverse choledochotomy with routine T-tube biliary drainage during LC has proven to be safe and effective at up to 23 years of follow-up, with no evidence of CBD stricture when the procedure is performed with a correct technique.

Dark Energy Survey Year 1 results: the impact of galaxy neighbours on weak lensing cosmology with IM3SHAPE

DOE PAGES

Samuroff, S.

2017-12-26

We use a suite of simulated images based on Year 1 of the Dark Energy Survey to explore the impact of galaxy neighbours on shape measurement and shear cosmology. The hoopoe image simulations include realistic blending, galaxy positions, and spatial variations in depth and PSF properties. Using the im3shape maximum-likelihood shape measurement code, we identify four mechanisms by which neighbours can have a non-negligible influence on shear estimation. These effects, if ignored, would contribute a net multiplicative bias ofmore » $$m \\sim 0.03 - 0.09$$ in the DES Y1 im3shape catalogue, though the precise impact will be dependent on both the measurement code and the selection cuts applied. This can be reduced to percentage level or less by removing objects with close neighbours, at a cost to the effective number density of galaxies $$n_\\mathrm{eff}$$ of 30%. We use the cosmological inference pipeline of DES Y1 to explore the cosmological implications of neighbour bias and show that omitting blending from the calibration simulation for DES Y1 would bias the inferred clustering amplitude $$S_8\\equiv \\sigma_8 (\\Omega _\\mathrm{m} /0.3)^{0.5}$$ by $$2 \\sigma$$ towards low values. Lastly, we use the hoopoe simulations to test the effect of neighbour-induced spatial correlations in the multiplicative bias. We find the impact on the recovered $$S_8$$ of ignoring such correlations to be subdominant to statistical error at the current level of precision.« less

Dark Energy Survey Year 1 results: the impact of galaxy neighbours on weak lensing cosmology with IM3SHAPE

DOE Office of Scientific and Technical Information (OSTI.GOV)

Samuroff, S.

We use a suite of simulated images based on Year 1 of the Dark Energy Survey to explore the impact of galaxy neighbours on shape measurement and shear cosmology. The hoopoe image simulations include realistic blending, galaxy positions, and spatial variations in depth and PSF properties. Using the im3shape maximum-likelihood shape measurement code, we identify four mechanisms by which neighbours can have a non-negligible influence on shear estimation. These effects, if ignored, would contribute a net multiplicative bias ofmore » $$m \\sim 0.03 - 0.09$$ in the DES Y1 im3shape catalogue, though the precise impact will be dependent on both the measurement code and the selection cuts applied. This can be reduced to percentage level or less by removing objects with close neighbours, at a cost to the effective number density of galaxies $$n_\\mathrm{eff}$$ of 30%. We use the cosmological inference pipeline of DES Y1 to explore the cosmological implications of neighbour bias and show that omitting blending from the calibration simulation for DES Y1 would bias the inferred clustering amplitude $$S_8\\equiv \\sigma_8 (\\Omega _\\mathrm{m} /0.3)^{0.5}$$ by $$2 \\sigma$$ towards low values. Lastly, we use the hoopoe simulations to test the effect of neighbour-induced spatial correlations in the multiplicative bias. We find the impact on the recovered $$S_8$$ of ignoring such correlations to be subdominant to statistical error at the current level of precision.« less

Analysis and Comparison on the Flood Simulation in Typical Hilly & Semi-mountainous Region

NASA Astrophysics Data System (ADS)

Luan, Qinghua; Wang, Dong; Zhang, Xiang; Liu, Jiahong; Fu, Xiaoran; Zhang, Kun; Ma, Jun

2017-12-01

Water-logging and flood are both serious in hilly and semi-mountainous cities of China, but the related research is rare. Lincheng Economic Development Zone (EDZ) in Hebei Province as the typical city was selected and storm water management model (SWMM) was applied for flood simulation in this study. The regional model was constructed through calibrating and verifying the runoff coefficient of different flood processes. Different designed runoff processes in five-year, ten-year and twenty-year return periods in basic scenario and in the low impact development (LID) scenario, respectively, were simulated and compared. The result shows that: LID measures have effect on peak reduction in the study area, but the effectiveness is not significant; the effectiveness of lagging peak time is poor. These simulation results provide decision support for the rational construction of LID in the study area, and provide the references for regional rain flood management.