WorldWideScience

Sample records for multiple-code simulation study

  1. Hearing the voices of service user researchers in collaborative qualitative data analysis: the case for multiple coding.

    Science.gov (United States)

    Sweeney, Angela; Greenwood, Kathryn E; Williams, Sally; Wykes, Til; Rose, Diana S

    2013-12-01

    Health research is frequently conducted in multi-disciplinary teams, with these teams increasingly including service user researchers. Whilst it is common for service user researchers to be involved in data collection--most typically interviewing other service users--it is less common for service user researchers to be involved in data analysis and interpretation. This means that a unique and significant perspective on the data is absent. This study aims to use an empirical report of a study on Cognitive Behavioural Therapy for psychosis (CBTp) to demonstrate the value of multiple coding in enabling service users voices to be heard in team-based qualitative data analysis. The CBTp study employed multiple coding to analyse service users' discussions of CBT for psychosis (CBTp) from the perspectives of a service user researcher, clinical researcher and psychology assistant. Multiple coding was selected to enable multiple perspectives to analyse and interpret data, to understand and explore differences and to build multi-disciplinary consensus. Multiple coding enabled the team to understand where our views were commensurate and incommensurate and to discuss and debate differences. Through the process of multiple coding, we were able to build strong consensus about the data from multiple perspectives, including that of the service user researcher. Multiple coding is an important method for understanding and exploring multiple perspectives on data and building team consensus. This can be contrasted with inter-rater reliability which is only appropriate in limited circumstances. We conclude that multiple coding is an appropriate and important means of hearing service users' voices in qualitative data analysis. © 2012 John Wiley & Sons Ltd.

  2. Coding in pigeons: Multiple-coding versus single-code/default strategies.

    Science.gov (United States)

    Pinto, Carlos; Machado, Armando

    2015-05-01

    To investigate the coding strategies that pigeons may use in a temporal discrimination tasks, pigeons were trained on a matching-to-sample procedure with three sample durations (2s, 6s and 18s) and two comparisons (red and green hues). One comparison was correct following 2-s samples and the other was correct following both 6-s and 18-s samples. Tests were then run to contrast the predictions of two hypotheses concerning the pigeons' coding strategies, the multiple-coding and the single-code/default. According to the multiple-coding hypothesis, three response rules are acquired, one for each sample. According to the single-code/default hypothesis, only two response rules are acquired, one for the 2-s sample and a "default" rule for any other duration. In retention interval tests, pigeons preferred the "default" key, a result predicted by the single-code/default hypothesis. In no-sample tests, pigeons preferred the key associated with the 2-s sample, a result predicted by multiple-coding. Finally, in generalization tests, when the sample duration equaled 3.5s, the geometric mean of 2s and 6s, pigeons preferred the key associated with the 6-s and 18-s samples, a result predicted by the single-code/default hypothesis. The pattern of results suggests the need for models that take into account multiple sources of stimulus control. © Society for the Experimental Analysis of Behavior.

  3. Multiple coding strategies in the retention of musical tones by possessors of absolute pitch.

    Science.gov (United States)

    Zatorre, R J; Beckett, C

    1989-09-01

    Eighteen musicians with absolute pitch (AP) confirmed by screening tests participated in tonal and verbal short-term-retention tasks. In the tonal task, subjects identified three successive piano tones by their letter names. Recall of these note names after 18 sec of counting backwards was near perfect. Recall after an 18-sec delay filled with random piano tones was also near perfect. In contrast, the same subjects demonstrated significant forgetting when required to retain letter trigrams while counting backwards for 18 sec. These results were essentially replicated in a second experiment using longer (27 sec) retention intervals, a more demanding verbal interference task, and an active musical interference task (singing a descending scale). We interpret these results as indicating that retention of note names by possessors of AP is not limited to verbal encoding; rather, multiple codes (e.g., auditory, kinesthetic, and visual imagery) are probably used.

  4. Conducting Simulation Studies in Psychometrics

    Science.gov (United States)

    Feinberg, Richard A.; Rubright, Jonathan D.

    2016-01-01

    Simulation studies are fundamental to psychometric discourse and play a crucial role in operational and academic research. Yet, resources for psychometricians interested in conducting simulations are scarce. This Instructional Topics in Educational Measurement Series (ITEMS) module is meant to address this deficiency by providing a comprehensive…

  5. Simulation in International Studies

    Science.gov (United States)

    Boyer, Mark A.

    2011-01-01

    Social scientists have long worked to replicate real-world phenomena in their research and teaching environments. Unlike our biophysical science colleagues, we are faced with an area of study that is not governed by the laws of physics and other more predictable relationships. As a result, social scientists, and international studies scholars more…

  6. Chernobyl reactor transient simulation study

    International Nuclear Information System (INIS)

    Gaber, F.A.; El Messiry, A.M.

    1988-01-01

    This paper deals with the Chernobyl nuclear power station transient simulation study. The Chernobyl (RBMK) reactor is a graphite moderated pressure tube type reactor. It is cooled by circulating light water that boils in the upper parts of vertical pressure tubes to produce steam. At equilibrium fuel irradiation, the RBMK reactor has a positive void reactivity coefficient. However, the fuel temperature coefficient is negative and the net effect of a power change depends upon the power level. Under normal operating conditions the net effect (power coefficient) is negative at full power and becomes positive under certain transient conditions. A series of dynamic performance transient analysis for RBMK reactor, pressurized water reactor (PWR) and fast breeder reactor (FBR) have been performed using digital simulator codes, the purpose of this transient study is to show that an accident of Chernobyl's severity does not occur in PWR or FBR nuclear power reactors. This appears from the study of the inherent, stability of RBMK, PWR and FBR under certain transient conditions. This inherent stability is related to the effect of the feed back reactivity. The power distribution stability in the graphite RBMK reactor is difficult to maintain throughout its entire life, so the reactor has an inherent instability. PWR has larger negative temperature coefficient of reactivity, therefore, the PWR by itself has a large amount of natural stability, so PWR is inherently safe. FBR has positive sodium expansion coefficient, therefore it has insufficient stability it has been concluded that PWR has safe operation than FBR and RBMK reactors

  7. Multiple Codes, Multiple Impressions: An Analysis of Doctor-Client Encounters in Nigeria

    Science.gov (United States)

    Odebunmi, Akin

    2013-01-01

    Existing studies on doctor-client interactions have largely focused on monolingual encounters and the interactional effects and functions of the languages used in the communication between doctors and their clients. They have neither, to a large extent, examined the several codes employed in single encounters and their pragmatic roles nor given…

  8. Study of swelling by simulation

    International Nuclear Information System (INIS)

    Gilbon, D.; Le Naour, L.; Didout, G.

    1983-06-01

    Fuel cans and hexagonal tubes containing the pins must withstand high irradiation doses (220 or even 275 dpa) with a low swelling. Qualification of a new alloy for claddings requires several years of irradiation on a reactor. For a fast first selection simulation by 1MeV electron or heavy ions enhance radiation damages. Principles of these techniques are recalled and some examples mainly with steel 316 are given. Results are compared with results obtained in reactor to determine simulation limits. The method is not valid in the case of a structural instability of the irradiated material in a reactor [fr

  9. Operations planning simulation: Model study

    Science.gov (United States)

    1974-01-01

    The use of simulation modeling for the identification of system sensitivities to internal and external forces and variables is discussed. The technique provides a means of exploring alternate system procedures and processes, so that these alternatives may be considered on a mutually comparative basis permitting the selection of a mode or modes of operation which have potential advantages to the system user and the operator. These advantages are measurements is system efficiency are: (1) the ability to meet specific schedules for operations, mission or mission readiness requirements or performance standards and (2) to accomplish the objectives within cost effective limits.

  10. Dual-energy mammography: simulation studies

    International Nuclear Information System (INIS)

    Bliznakova, K; Kolitsi, Z; Pallikarakis, N

    2006-01-01

    This paper presents a mammography simulator and demonstrates its applicability in feasibility studies in dual-energy (DE) subtraction mammography. This mammography simulator is an evolution of a previously presented x-ray imaging simulation system, which has been extended with new functionalities that are specific for DE simulations. The new features include incident exposure and dose calculations, the implementation of a DE subtraction algorithm as well as amendments to the detector and source modelling. The system was then verified by simulating experiments and comparing their results against published data. The simulator was used to carry out a feasibility study of the applicability of DE techniques in mammography, and more precisely to examine whether this modality could result in better visualization and detection of microcalcifications. Investigations were carried out using a 3D breast software phantom of average thickness, monoenergetic and polyenergetic beam spectra and various detector configurations. Dual-shot techniques were simulated. Results showed the advantage of using monoenergetic in comparison with polyenergetic beams. Optimization studies with monochromatic sources were carried out to obtain the optimal low and high incident energies, based on the assessment of the figure of merit of the simulated microcalcifications in the subtracted images. The results of the simulation study with the optimal energies demonstrated that the use of the DE technique can improve visualization and increase detectability, allowing identification of microcalcifications of sizes as small as 200 μm. The quantitative results are also verified by means of a visual inspection of the synthetic images

  11. Crop micrometeorology : a simulation study

    NARCIS (Netherlands)

    Goudriaan, J.

    1977-01-01

    This monograph presents the results of a detailed study in micrometeorology; one of the sciences that play an important role in production ecology. The purpose is to explain the microweather as a function of the properties of plant and soil, and of the weather conditions prevalent at some

  12. Preliminary simulation study of doppler reflectometry

    International Nuclear Information System (INIS)

    Ishii, Yuta; Hojo, Hitoshi; Yoshikawa, Masashi; Ichimura, Makoto; Haraguchi, Yusuke; Imai, Tsuyoshi; Mase, Atsushi

    2010-01-01

    A preliminary simulation study of Doppler reflectometry is performed. The simulations solve Maxwell's equations by a finite difference time domain (FDTD) code method in two dimensions. A moving corrugated metal target is used as a plasma cutoff layer to study the basic features of Doppler reflectometry. We examined the effects of the full width at half maximum (FWHM) of the electromagnetic waves and the corrugation depth of the metal target. Furthermore, the effect of a nonuniform plasma is studied using this FDTD analysis. The Doppler shift and velocity are compared with those obtained from FDTD analysis of a uniform plasma. (author)

  13. A Distributed Flow Rate Control Algorithm for Networked Agent System with Multiple Coding Rates to Optimize Multimedia Data Transmission

    Directory of Open Access Journals (Sweden)

    Shuai Zeng

    2013-01-01

    Full Text Available With the development of wireless technologies, mobile communication applies more and more extensively in the various walks of life. The social network of both fixed and mobile users can be seen as networked agent system. At present, kinds of devices and access network technology are widely used. Different users in this networked agent system may need different coding rates multimedia data due to their heterogeneous demand. This paper proposes a distributed flow rate control algorithm to optimize multimedia data transmission of the networked agent system with the coexisting various coding rates. In this proposed algorithm, transmission path and upload bandwidth of different coding rate data between source node, fixed and mobile nodes are appropriately arranged and controlled. On the one hand, this algorithm can provide user nodes with differentiated coding rate data and corresponding flow rate. On the other hand, it makes the different coding rate data and user nodes networked, which realizes the sharing of upload bandwidth of user nodes which require different coding rate data. The study conducts mathematical modeling on the proposed algorithm and compares the system that adopts the proposed algorithm with the existing system based on the simulation experiment and mathematical analysis. The results show that the system that adopts the proposed algorithm achieves higher upload bandwidth utilization of user nodes and lower upload bandwidth consumption of source node.

  14. Digital Simulation Games for Social Studies Classrooms

    Science.gov (United States)

    Devlin-Scherer, Roberta; Sardone, Nancy B.

    2010-01-01

    Data from ten teacher candidates studying teaching methods were analyzed to determine perceptions toward digital simulation games in the area of social studies. This research can be used as a conceptual model of how current teacher candidates react to new methods of instruction and determine how education programs might change existing curricula…

  15. Simulator Studies of the Deep Stall

    Science.gov (United States)

    White, Maurice D.; Cooper, George E.

    1965-01-01

    Simulator studies of the deep-stall problem encountered with modern airplanes are discussed. The results indicate that the basic deep-stall tendencies produced by aerodynamic characteristics are augmented by operational considerations. Because of control difficulties to be anticipated in the deep stall, it is desirable that adequate safeguards be provided against inadvertent penetrations.

  16. Preliminary simulation studies of accelerator cavity loading

    International Nuclear Information System (INIS)

    Faehl, R.J.

    1980-06-01

    Two-dimensional simulations of loading effects in a 350 MHz accelerator cavity have been performed. Electron currents of 1-10 kA have been accelerated in 5 MV/m fields. Higher order cavity modes induced by the beam may lead to emittance growth. Operation in an autoaccelerator mode has been studied

  17. Driving Simulator Development and Performance Study

    OpenAIRE

    Juto, Erik

    2010-01-01

    The driving simulator is a vital tool for much of the research performed at theSwedish National Road and Transport Institute (VTI). Currently VTI posses three driving simulators, two high fidelity simulators developed and constructed by VTI, and a medium fidelity simulator from the German company Dr.-Ing. Reiner Foerst GmbH. The two high fidelity simulators run the same simulation software, developed at VTI. The medium fidelity simulator runs a proprietary simulation software. At VTI there is...

  18. Mobile-ip Aeronautical Network Simulation Study

    Science.gov (United States)

    Ivancic, William D.; Tran, Diepchi T.

    2001-01-01

    NASA is interested in applying mobile Internet protocol (mobile-ip) technologies to its space and aeronautics programs. In particular, mobile-ip will play a major role in the Advanced Aeronautic Transportation Technology (AATT), the Weather Information Communication (WINCOMM), and the Small Aircraft Transportation System (SATS) aeronautics programs. This report presents the results of a simulation study of mobile-ip for an aeronautical network. The study was performed to determine the performance of the transmission control protocol (TCP) in a mobile-ip environment and to gain an understanding of how long delays, handoffs, and noisy channels affect mobile-ip performance.

  19. DWPF Simulant CPC Studies For SB8

    Energy Technology Data Exchange (ETDEWEB)

    Newell, J. D.

    2013-09-25

    Prior to processing a Sludge Batch (SB) in the Defense Waste Processing Facility (DWPF), flowsheet studies using simulants are performed. Typically, the flowsheet studies are conducted based on projected composition(s). The results from the flowsheet testing are used to 1) guide decisions during sludge batch preparation, 2) serve as a preliminary evaluation of potential processing issues, and 3) provide a basis to support the Shielded Cells qualification runs performed at the Savannah River National Laboratory (SRNL). SB8 was initially projected to be a combination of the Tank 40 heel (Sludge Batch 7b), Tank 13, Tank 12, and the Tank 51 heel. In order to accelerate preparation of SB8, the decision was made to delay the oxalate-rich material from Tank 12 to a future sludge batch. SB8 simulant studies without Tank 12 were reported in a separate report.1 The data presented in this report will be useful when processing future sludge batches containing Tank 12. The wash endpoint target for SB8 was set at a significantly higher sodium concentration to allow acceptable glass compositions at the targeted waste loading. Four non-coupled tests were conducted using simulant representing Tank 40 at 110-146% of the Koopman Minimum Acid requirement. Hydrogen was generated during high acid stoichiometry (146% acid) SRAT testing up to 31% of the DWPF hydrogen limit. SME hydrogen generation reached 48% of of the DWPF limit for the high acid run. Two non-coupled tests were conducted using simulant representing Tank 51 at 110-146% of the Koopman Minimum Acid requirement. Hydrogen was generated during high acid stoichiometry SRAT testing up to 16% of the DWPF limit. SME hydrogen generation reached 49% of the DWPF limit for hydrogen in the SME for the high acid run. Simulant processing was successful using previously established antifoam addition strategy. Foaming during formic acid addition was not observed in any of the runs. Nitrite was destroyed in all runs and no N2O was detected

  20. A simulation study on garment manufacturing process

    Science.gov (United States)

    Liong, Choong-Yeun; Rahim, Nur Azreen Abdul

    2015-02-01

    Garment industry is an important industry and continues to evolve in order to meet the consumers' high demands. Therefore, elements of innovation and improvement are important. In this work, research studies were conducted at a local company in order to model the sewing process of clothes manufacturing by using simulation modeling. Clothes manufacturing at the company involves 14 main processes, which are connecting the pattern, center sewing and side neating, pockets sewing, backside-sewing, attaching the front and back, sleeves preparation, attaching the sleeves and over lock, collar preparation, collar sewing, bottomedge sewing, buttonholing sewing, removing excess thread, marking button, and button cross sewing. Those fourteen processes are operated by six tailors only. The last four sets of processes are done by a single tailor. Data collection was conducted by on site observation and the probability distribution of processing time for each of the processes is determined by using @Risk's Bestfit. Then a simulation model is developed using Arena Software based on the data collected. Animated simulation model is developed in order to facilitate understanding and verifying that the model represents the actual system. With such model, what if analysis and different scenarios of operations can be experimented with virtually. The animation and improvement models will be presented in further work.

  1. One-dimensional plasma simulation studies

    International Nuclear Information System (INIS)

    Friberg, Ari; Virtamo, Jorma

    1976-01-01

    Some basic plasma phenomena are studied by a one-dimensional electrostatic simulation code. A brief description of the code and its application to a test problem is given. The experiments carried out include Landau damping of an excited wave, particle retardation by smoothed field and beam-plasma instability. In each case, the set-up of the experiment is described and the results are compared with theoretical predictions. In the theoretical discussions, the oscillatory behaviour found in the Landau damping experiment is explained, an explicit formula for the particle retardation rate is derived and a rudimentary picture of the beam-plasma instability in terms of quasilinear theory is given. (author)

  2. DWPF simulant CPC studies for SB8

    Energy Technology Data Exchange (ETDEWEB)

    Koopman, D. C.; Zamecnik, J. R.

    2013-06-25

    The Savannah River National Laboratory (SRNL) accepted a technical task request (TTR) from Waste Solidification Engineering to perform simulant tests to support the qualification of Sludge Batch 8 (SB8) and to develop the flowsheet for SB8 in the Defense Waste Processing Facility (DWPF). These efforts pertained to the DWPF Chemical Process Cell (CPC). Separate studies were conducted for frit development and glass properties (including REDOX). The SRNL CPC effort had two primary phases divided by the decision to drop Tank 12 from the SB8 constituents. This report focuses on the second phase with SB8 compositions that do not contain the Tank 12 piece. A separate report will document the initial phase of SB8 testing that included Tank 12. The second phase of SB8 studies consisted of two sets of CPC studies. The first study involved CPC testing of an SB8 simulant for Tank 51 to support the CPC demonstration of the washed Tank 51 qualification sample in the SRNL Shielded Cells facility. SB8-Tank 51 was a high iron-low aluminum waste with fairly high mercury and moderate noble metal concentrations. Tank 51 was ultimately washed to about 1.5 M sodium which is the highest wash endpoint since SB3-Tank 51. This study included three simulations of the DWPF Sludge Receipt and Adjustment Tank (SRAT) cycle and Slurry Mix Evaporator (SME) cycle with the sludge-only flowsheet at nominal DWPF processing conditions and three different acid stoichiometries. These runs produced a set of recommendations that were used to guide the successful SRNL qualification SRAT/SME demonstration with actual Tank 51 washed waste. The second study involved five SRAT/SME runs with SB8-Tank 40 simulant. Four of the runs were designed to define the acid requirements for sludge-only processing in DWPF with respect to nitrite destruction and hydrogen generation. The fifth run was an intermediate acid stoichiometry demonstration of the coupled flowsheet for SB8. These runs produced a set of processing

  3. DWPF simulant CPC studies for SB8

    International Nuclear Information System (INIS)

    Koopman, D. C.; Zamecnik, J. R.

    2013-01-01

    The Savannah River National Laboratory (SRNL) accepted a technical task request (TTR) from Waste Solidification Engineering to perform simulant tests to support the qualification of Sludge Batch 8 (SB8) and to develop the flowsheet for SB8 in the Defense Waste Processing Facility (DWPF). These efforts pertained to the DWPF Chemical Process Cell (CPC). Separate studies were conducted for frit development and glass properties (including REDOX). The SRNL CPC effort had two primary phases divided by the decision to drop Tank 12 from the SB8 constituents. This report focuses on the second phase with SB8 compositions that do not contain the Tank 12 piece. A separate report will document the initial phase of SB8 testing that included Tank 12. The second phase of SB8 studies consisted of two sets of CPC studies. The first study involved CPC testing of an SB8 simulant for Tank 51 to support the CPC demonstration of the washed Tank 51 qualification sample in the SRNL Shielded Cells facility. SB8-Tank 51 was a high iron-low aluminum waste with fairly high mercury and moderate noble metal concentrations. Tank 51 was ultimately washed to about 1.5 M sodium which is the highest wash endpoint since SB3-Tank 51. This study included three simulations of the DWPF Sludge Receipt and Adjustment Tank (SRAT) cycle and Slurry Mix Evaporator (SME) cycle with the sludge-only flowsheet at nominal DWPF processing conditions and three different acid stoichiometries. These runs produced a set of recommendations that were used to guide the successful SRNL qualification SRAT/SME demonstration with actual Tank 51 washed waste. The second study involved five SRAT/SME runs with SB8-Tank 40 simulant. Four of the runs were designed to define the acid requirements for sludge-only processing in DWPF with respect to nitrite destruction and hydrogen generation. The fifth run was an intermediate acid stoichiometry demonstration of the coupled flowsheet for SB8. These runs produced a set of processing

  4. Heat load material studies: Simulated tokamak disruptions

    International Nuclear Information System (INIS)

    Gahl, J.M.; McDonald, J.M.; Zakharov, A.; Tserevitinov, S.; Barabash, V.; Guseva, M.

    1991-01-01

    It is clear that an improved understanding of the effects of tokamak disruptions on plasma facing component materials is needed for the ITER program. very large energy fluxes are predicted to be deposited in ITER and could be very damaging to the machine. During 1991, Sandia National Laboratories and the University of New Mexico conducted cooperative tokamak disruption simulation experiments at several Soviet facilities. These facilities were located at the Efremov Institute in Leningrad, the Kurchatov Atomic Energy Institute (Troisk and Moscow) and the Institute for Physical Chemistry of the Soviet Adademy of Sciences in Moscow. Erosion of graphite from plasma stream impact is seen to be much less than that observed with laser or electron beams with similar energy fluxes. This, along with other data obtained, seem to suggest that the ''vapor shielding'' effect is a very important phenomenon in the study of graphite erosion during tokamak disruption

  5. Molecular dynamic simulation study of molten cesium

    Directory of Open Access Journals (Sweden)

    Yeganegi Saeid

    2017-01-01

    Full Text Available Molecular dynamics simulations were performed to study thermodynamics and structural properties of expanded caesium fluid. Internal pressure, radial distribution functions (RDFs, coordination numbers and diffusion coefficients have been calculated at temperature range 700–1600 K and pressure range 100–800 bar. We used the internal pressure to predict the metal–non-metal transition occurrence region. RDFs were calculated at wide ranges of temperature and pressure. The coordination numbers decrease and positions of the first peak of RDFs slightly increase as the temperature increases and pressure decreases. The calculated self-diffusion coefficients at various temperatures and pressures show no distinct boundary between Cs metallic fluid and its expanded fluid where it continuously increases with temperature.

  6. Quench Simulation Studies: Program documentation of SPQR

    CERN Document Server

    Sonnemann, F

    2001-01-01

    Quench experiments are being performed on prototypes of the superconducting magnets and busbars to determine the adequate design and protection. Many tests can only be understood correctly with the help of quench simulations that model the thermo-hydraulic and electrodynamic processes during a quench. In some cases simulations are the only method to scale the experimental results of prototype measurements to match the situation of quenching superconducting elements in the LHC. This note introduces the theoretical quench model and the use of the simulation program SPQR (Simulation Program for Quench Research), which has been developed to compute the quench process in superconducting magnets and busbars. The model approximates the heat balance equation with the finite difference method including the temperature dependence of the material parameters. SPQR allows the simulation of longitudinal quench propagation along a superconducting cable, the transverse propagation between adjacent conductors, heat transfer i...

  7. Simulation study of pixel detector charge digitization

    Science.gov (United States)

    Wang, Fuyue; Nachman, Benjamin; Sciveres, Maurice; Lawrence Berkeley National Laboratory Team

    2017-01-01

    Reconstruction of tracks from nearly overlapping particles, called Tracking in Dense Environments (TIDE), is an increasingly important component of many physics analyses at the Large Hadron Collider as signatures involving highly boosted jets are investigated. TIDE makes use of the charge distribution inside a pixel cluster to resolve tracks that share one of more of their pixel detector hits. In practice, the pixel charge is discretized using the Time-over-Threshold (ToT) technique. More charge information is better for discrimination, but more challenging for designing and operating the detector. A model of the silicon pixels has been developed in order to study the impact of the precision of the digitized charge distribution on distinguishing multi-particle clusters. The output of the GEANT4-based simulation is used to train neutral networks that predict the multiplicity and location of particles depositing energy inside one cluster of pixels. By studying the multi-particle cluster identification efficiency and position resolution, we quantify the trade-off between the number of ToT bits and low-level tracking inputs. As both ATLAS and CMS are designing upgraded detectors, this work provides guidance for the pixel module designs to meet TIDE needs. Work funded by the China Scholarship Council and the Office of High Energy Physics of the U.S. Department of Energy under contract DE-AC02-05CH11231.

  8. Deep Space Storm Shelter Simulation Study

    Science.gov (United States)

    Dugan, Kathryn; Phojanamongkolkij, Nipa; Cerro, Jeffrey; Simon, Matthew

    2015-01-01

    Missions outside of Earth's magnetic field are impeded by the presence of radiation from galactic cosmic rays and solar particle events. To overcome this issue, NASA's Advanced Exploration Systems Radiation Works Storm Shelter (RadWorks) has been studying different radiation protective habitats to shield against the onset of solar particle event radiation. These habitats have the capability of protecting occupants by utilizing available materials such as food, water, brine, human waste, trash, and non-consumables to build short-term shelters. Protection comes from building a barrier with the materials that dampens the impact of the radiation on astronauts. The goal of this study is to develop a discrete event simulation, modeling a solar particle event and the building of a protective shelter. The main hallway location within a larger habitat similar to the International Space Station (ISS) is analyzed. The outputs from this model are: 1) the total area covered on the shelter by the different materials, 2) the amount of radiation the crew members receive, and 3) the amount of time for setting up the habitat during specific points in a mission given an event occurs.

  9. Simulation study of the high intensity S-Band photoinjector

    Energy Technology Data Exchange (ETDEWEB)

    Zhu, Xiongwei; Nakajima, Kazuhisa [High Energy Accelerator Research Organization, Tsukuba, Ibaraki (Japan)

    2001-10-01

    In this paper, we report the results of simulation study of the high intensity S-Band photoinjector. The aim of the simulation study is to transport high bunch charge with low emittance evolution. The simulation result shows that 7nC bunch with rms emittance 22.3 {pi} mm mrad can be outputted at the exit of photoinjector. (author)

  10. Simulation study of the high intensity S-Band photoinjector

    International Nuclear Information System (INIS)

    Zhu, Xiongwei; Nakajima, Kazuhisa

    2001-01-01

    In this paper, we report the results of simulation study of the high intensity S-Band photoinjector. The aim of the simulation study is to transport high bunch charge with low emittance evolution. The simulation result shows that 7nC bunch with rms emittance 22.3 π mm mrad can be outputted at the exit of photoinjector. (author)

  11. Conducting Simulation Studies in the R Programming Environment.

    Science.gov (United States)

    Hallgren, Kevin A

    2013-10-12

    Simulation studies allow researchers to answer specific questions about data analysis, statistical power, and best-practices for obtaining accurate results in empirical research. Despite the benefits that simulation research can provide, many researchers are unfamiliar with available tools for conducting their own simulation studies. The use of simulation studies need not be restricted to researchers with advanced skills in statistics and computer programming, and such methods can be implemented by researchers with a variety of abilities and interests. The present paper provides an introduction to methods used for running simulation studies using the R statistical programming environment and is written for individuals with minimal experience running simulation studies or using R. The paper describes the rationale and benefits of using simulations and introduces R functions relevant for many simulation studies. Three examples illustrate different applications for simulation studies, including (a) the use of simulations to answer a novel question about statistical analysis, (b) the use of simulations to estimate statistical power, and (c) the use of simulations to obtain confidence intervals of parameter estimates through bootstrapping. Results and fully annotated syntax from these examples are provided.

  12. Learning with a strategic management simulation game: A case study

    OpenAIRE

    Loon, Mark; Evans, Jason; Kerridge, Clive

    2015-01-01

    The use of simulation games as a pedagogic method is well established though its effective use is context-driven. This study adds to the increasing growing body of empirical evidence of the effectiveness of simulation games but more importantly emphasises why by explaining the instructional design implemented reflecting best practices. This multi-method study finds evidence that student learning was enhanced through the use of simulation games, reflected in the two key themes; simulation game...

  13. Simulation studies of GST phase change alloys

    Science.gov (United States)

    Martyna, Glenn

    2008-03-01

    In order to help drive post-Moore's Law technology development, switching processes involving novel materials, in particular, GeSbTe (GST) alloys are being investigated for use in memory and eFuse applications. An anneal/quench thermal process crystallizes/amorphosizes a GST alloy which then has a low/high resistance and thereby forms a readable/writeable bit; for example, a ``one'' might be the low resistance, conducting crystalline state and a ``zero'' might be the high resistance, glassy state. There are many open questions about the precise nature of the structural transitions and the coupling to electronic structure changes. Computational and experimental studies of the effect of pressure on the GST materials were initiated in order to probe the physics behind the thermal switching process. A new pathway to reversible phase change involving pressure-induced structural metal insulator transitions was discovered. In a binary GS system, a room-temperature, direct, pressure-induced transformation from the high resistance amorphous phase to the low resistance crystalline phase was observed experimentally while the reverse process under tensile load was demonstrated via ab initio MD simulations performed on IBM's Blue Gene/L enabled by massively parallel software. Pressure induced transformations of the ternary material GST-225 (Ge2Sb2Te5) were, also, examined In the talk, the behavior of the two systems will be compared and insight into the nature of the phase change given.

  14. Plasma simulation studies using multilevel physics models

    International Nuclear Information System (INIS)

    Park, W.; Belova, E.V.; Fu, G.Y.; Tang, X.Z.; Strauss, H.R.; Sugiyama, L.E.

    1999-01-01

    The question of how to proceed toward ever more realistic plasma simulation studies using ever increasing computing power is addressed. The answer presented here is the M3D (Multilevel 3D) project, which has developed a code package with a hierarchy of physics levels that resolve increasingly complete subsets of phase-spaces and are thus increasingly more realistic. The rationale for the multilevel physics models is given. Each physics level is described and examples of its application are given. The existing physics levels are fluid models (3D configuration space), namely magnetohydrodynamic (MHD) and two-fluids; and hybrid models, namely gyrokinetic-energetic-particle/MHD (5D energetic particle phase-space), gyrokinetic-particle-ion/fluid-electron (5D ion phase-space), and full-kinetic-particle-ion/fluid-electron level (6D ion phase-space). Resolving electron phase-space (5D or 6D) remains a future project. Phase-space-fluid models are not used in favor of δf particle models. A practical and accurate nonlinear fluid closure for noncollisional plasmas seems not likely in the near future. copyright 1999 American Institute of Physics

  15. Plasma simulation studies using multilevel physics models

    International Nuclear Information System (INIS)

    Park, W.; Belova, E.V.; Fu, G.Y.

    2000-01-01

    The question of how to proceed toward ever more realistic plasma simulation studies using ever increasing computing power is addressed. The answer presented here is the M3D (Multilevel 3D) project, which has developed a code package with a hierarchy of physics levels that resolve increasingly complete subsets of phase-spaces and are thus increasingly more realistic. The rationale for the multilevel physics models is given. Each physics level is described and examples of its application are given. The existing physics levels are fluid models (3D configuration space), namely magnetohydrodynamic (MHD) and two-fluids; and hybrid models, namely gyrokinetic-energetic-particle/MHD (5D energetic particle phase-space), gyrokinetic-particle-ion/fluid-electron (5D ion phase-space), and full-kinetic-particle-ion/fluid-electron level (6D ion phase-space). Resolving electron phase-space (5D or 6D) remains a future project. Phase-space-fluid models are not used in favor of delta f particle models. A practical and accurate nonlinear fluid closure for noncollisional plasmas seems not likely in the near future

  16. Computer Simulation Studies of Trishomocubane Heptapeptide of ...

    African Journals Online (AJOL)

    NICO

    Trishomocubane, molecular dynamics, Amber, CLASICO, β-turn, α-helical. 1. Introduction .... MD simulations of Ac-Ala3-Tris-Ala3-NHMe explicitly in MEOH. 3. Results and .... worthwhile to group all conformations into clusters according to.

  17. White book Escrime. Climatic simulation studies

    International Nuclear Information System (INIS)

    Terray, L.; Braconnot, P.

    2007-01-01

    The ESCRIME project aims to manage the analysis realized on the climatic simulations on the framework of the fourth report of the GIEC (group of intergovernmental experts on the climate evolution), in particularly the simulations based on french models. This white book is constituted by 8 chapters: the global scenario, the climatic sensibility, the variation modes, the regionalization and the extremes, the hydrological cycle, the polar regions and the cryo-sphere, the carbon cycle, detection and attributions. (A.L.B.)

  18. Development of a Cardiovascular Simulator for Studying Pulse Diagnosis Mechanisms

    Directory of Open Access Journals (Sweden)

    Min Jang

    2017-01-01

    Full Text Available This research was undertaken to develop a cardiovascular simulator for use in the study of pulse diagnosis. The physical (i.e., pulse wave transmission and reflection and physiological (i.e., systolic and diastolic pressure, pulse pressure, and mean pressure characteristics of the radial pulse wave were reproduced by our simulator. The simulator consisted of an arterial component and a pulse-generating component. Computer simulation was used to simplify the arterial component while maintaining the elastic modulus and artery size. To improve the reflected wave characteristics, a palmar arch was incorporated within the simulator. The simulated radial pulse showed good agreement with clinical data.

  19. A prospective study to determine the need for physical simulation following virtual simulation

    International Nuclear Information System (INIS)

    Valicenti, R.K.; Waterman, F.M.; Corn, B.W.; Sweet, J.; Curran, W.J.

    1996-01-01

    Purpose: Virtual simulation is CT based planning utilizing computed digitally reconstructed radiographs (DRRs) in a manner similar to conventional fluoroscopic simulation. However, conventional or physical simulation is still widely used to assure precise implementation of the devised plan. To evaluate the need for performing physical simulation, we prospectively studied patients undergoing virtual simulation who either had or did not have a subsequent physical simulation. Materials and Methods: From July, 1995 to February, 1996, 48 patients underwent conformal 4-field radiation therapy for prostate cancer using a commercial grade spiral CT simulator. All patients were immobilized in a foam body cast and positioned by using a fiducial laser marking system. Following prostate and seminal vesicle definition on a slice-by-slice basis, virtual simulation was performed. The isocenter defined by this process was marked on both the patient and the immobilization device before leaving the CT simulator room. The isocenter position of the devised plan was evaluated by three verification methods: physical simulation, first day treatment port filming, and port filming immediately following physical simulation. Simulator radiographs and port films were compared against DRRs for x, y, and z deviations of the isocenter. These deviations were used as a measure of the implementation precision achieved by each verification method. Results: Thirty-seven patients underwent physical simulation and first day port filming. Eleven had first day treatment verification films only and never had a physical simulation. A total of 79 simulator radiographs and 126 first day treatment port films were reviewed. The tabulation of all deviations is as follows: There was significantly more setup error (≥ 5 mm) observed when the devised treatment was implemented in the treatment room as opposed to the physical simulator. The physical simulator did not lead to a significant reduction in setup error

  20. Simulation studies on high-gradient experiments

    International Nuclear Information System (INIS)

    Yamaguchi, S.

    1992-12-01

    Computer simulation of the characteristics of the dark current emitted from a 0.6 m long S-band accelerating structure has been made. The energy spectra and the dependence of the dark current on the structure length were simulated. By adjusting the secondary electron emission (SEE) coefficients, the simulated energy spectra qualitatively reproduced the observed ones. It was shown that the dark current increases exponentially with the structure length. The measured value of the multiplication factor of the dark current per unit cell can be explained if the SEE coefficient is set to 1.2. The critical gradient for dark current capture E cri has been calculated for two structures of 180 cells. They are E cri [MV/m] = 13.1 f and 8.75 f for a/λ = 0.089 and 0.16, respectively, where f is the frequency in GHz, a the iris diameter and λ the wave length

  1. Conducting Simulation Studies in the R Programming Environment

    Directory of Open Access Journals (Sweden)

    Kevin A. Hallgren

    2013-10-01

    Full Text Available Simulation studies allow researchers to answer specific questions about data analysis, statistical power, and best-practices for obtainingaccurate results in empirical research. Despite the benefits that simulation research can provide, many researchers are unfamiliar with available tools for conducting their own simulation studies. The use of simulation studies need not be restricted toresearchers with advanced skills in statistics and computer programming, and such methods can be implemented by researchers with a variety of abilities and interests. The present paper provides an introduction to methods used for running simulationstudies using the R statistical programming environment and is written for individuals with minimal experience running simulation studies or using R. The paper describes the rationale and benefits of using simulations and introduces R functions relevant for many simulation studies. Three examples illustrate different applications for simulation studies, including (a the use of simulations to answer a novel question about statistical analysis, (b the use of simulations to estimate statistical power, and (c the use of simulations to obtain confidence intervals of parameter estimates throughbootstrapping. Results and fully annotated syntax from these examples are provided.

  2. A study on the thermal expansion characteristics of simulated spent fuel and simulated DUPIC fuel

    International Nuclear Information System (INIS)

    Kang, Kweon Ho; Ryu, H. J.; Kim, H. S.; Song, K. C.; Yang, M. S.

    2001-10-01

    Thermal expansions of simulated spent PWR fuel and simulated DUPIC fuel were studied using a dilatometer in the temperature range from 298 to 1900 K. The densities of simulated spent PWR fuel and simulated DUPIC fuel used in the measurement were 10.28 g/cm3 (95.35 % of TD) and 10.26 g/cm3 (95.14 % of TD), respectively. Their linear thermal expansions of simulated fuels are higher than that of UO2, and the difference between these fuels and UO2 increases progressively as temperature increases. However, the difference between simulated spent PWR fuel and simulated DUPIC fuel can hardly be observed. For the temperature range from 298 to 1900 K, the values of the average linear thermal expansion coefficients for simulated spent PWR fuel and simulated DUPIC fuel are 1.391 10-5 and 1.393 10-5 K-1, respectively. As temperature increases to 1900 K, the relative densities of simulated spent PWR fuel and simulated DUPIC fuel decrease to 93.81 and 93.76 % of initial densities at 298 K, respectively

  3. A molecular dynamics simulation study of chloroform

    Science.gov (United States)

    Tironi, Ilario G.; van Gunsteren, Wilfred F.

    Three different chloroform models have been investigated using molecular dynamics computer simulation. The thermodynamic, structural and dynamic properties of the various models were investigated in detail. In particular, the potential energies, diffusion coefficients and rotational correlation times obtained for each model are compared with experiment. It is found that the theory of rotational Brownian motion fails in describing the rotational diffusion of chloroform. The force field of Dietz and Heinzinger was found to give good overall agreement with experiment. An extended investigation of this chloroform model has been performed. Values are reported for the isothermal compressibility, the thermal expansion coefficient and the constant volume heat capacity. The values agree well with experiment. The static and frequency dependent dielectric permittivity were computed from a 1·2 ns simulation conducted under reaction field boundary conditions. Considering the fact that the model is rigid with fixed partial charges, the static dielectric constant and Debye relaxation time compare well with experiment. From the same simulation the shear viscosity was computed using the off-diagonal elements of the pressure tensor, both via an Einstein type relation and via a Green-Kubo equation. The calculated viscosities show good agreement with experimental values. The excess Helmholtz energy is calculated using the thermodynamic integration technique and simulations of 50 and 80 ps. The value obtained for the excess Helmholtz energy matches the theoretical value within a few per cent.

  4. Computer Simulation Studies of Trishomocubane Heptapeptide of ...

    African Journals Online (AJOL)

    As part of an extension on the cage peptide chemistry, the present work involves an assessment of the conformational profile of trishomocubane heptapeptide of the type Ac-Ala3-Tris-Ala3-NHMe using molecular dynamics (MD) simulations. All MD protocols were explored within the framework of a molecular mechanics ...

  5. Assessing phylogenetic accuracy : a simulation study

    NARCIS (Netherlands)

    Heijerman, T.

    1995-01-01

    A simulation model of phylogeny, called GENESIS, was developed to evaluate and to estimate the qualities of various numerical taxonomic procedures. The model produces sets of imaginary species with known character state distributions and with known phylogenies. The model can be made to

  6. Partnering to Establish and Study Simulation in International Nursing Education.

    Science.gov (United States)

    Garner, Shelby L; Killingsworth, Erin; Raj, Leena

    The purpose of this article was to describe an international partnership to establish and study simulation in India. A pilot study was performed to determine interrater reliability among faculty new to simulation when evaluating nursing student competency performance. Interrater reliability was below the ideal agreement level. Findings in this study underscore the need to obtain baseline interrater reliability data before integrating competency evaluation into a simulation program.

  7. Assessing phylogenetic accuracy : a simulation study

    OpenAIRE

    Heijerman, T.

    1995-01-01

    A simulation model of phylogeny, called GENESIS, was developed to evaluate and to estimate the qualities of various numerical taxonomic procedures. The model produces sets of imaginary species with known character state distributions and with known phylogenies. The model can be made to produce these species and their phylogenies under different evolutionary conditions.

    Within GENESIS, there are two mathematical models that describe the diversification of the number of taxa. T...

  8. Simulation studies of the LAMPF proton linac

    International Nuclear Information System (INIS)

    Garnett, R.W.; Gray, E.R.; Rybarcyk, L.J.; Wangler, T.P.

    1995-01-01

    The LAMPF accelerator consists of two 0.75-MeV injectors, one for H + and the other for H - , a separate low-energy beam transport (LEBT) line for each beam species, a 0.75 to 100-MeV drift-tube linac (DTL) operating at 201.25-MHz, a 100-MeV transition region (TR), and a 100 to 800-MeV side-coupled linac (SCL) operating at 805-MHz. Each LEBT line consists of a series of quadrupoles to transport and transversely match the beam. The LEBT also contains a prebuncher, a main buncher, and an electrostatic deflector. The deflector is used to limit the fraction of a macropulse which is seen by the beam diagnostics throughout the linac. The DTL consists of four rf tanks and uses singlet FODO transverse focusing. The focusing period is doubled in the last two tanks by placing a quadrupole only in every other drift-tube. Doublet FDO transverse focusing is used in the SCL. The TR consists of separate transport lines for the H + and H - beams. The pathlengths for the two beams differ, by introducing bends, so as to delay arrival of one beam relative to the other and thereby produce the desired macropulse time structure. Peak beam currents typically range from 12 to 18-mA for varying macropulse lengths which give an average beam current of 1-mA. The number of particles per bunch is of the order 10 8 . The work presented here is an extension of previous work. The authors have attempted to do a more complete simulation by including modeling of the LEBT. No measurements of the longitudinal structure of the beam, except phase-scans, are performed at LAMPF. The authors show that, based on simulation results, the primary causes of beam spill are inefficient longitudinal capture and the lack of longitudinal matching. Measurements to support these claims are not presently made at LAMPF. However, agreement between measurement and simulation for the transverse beam properties and transmissions serve to benchmark the simulations

  9. Simulation

    CERN Document Server

    Ross, Sheldon

    2006-01-01

    Ross's Simulation, Fourth Edition introduces aspiring and practicing actuaries, engineers, computer scientists and others to the practical aspects of constructing computerized simulation studies to analyze and interpret real phenomena. Readers learn to apply results of these analyses to problems in a wide variety of fields to obtain effective, accurate solutions and make predictions about future outcomes. This text explains how a computer can be used to generate random numbers, and how to use these random numbers to generate the behavior of a stochastic model over time. It presents the statist

  10. Simulation Use in Paramedic Education Research (SUPER): A Descriptive Study.

    Science.gov (United States)

    McKenna, Kim D; Carhart, Elliot; Bercher, Daniel; Spain, Andrew; Todaro, John; Freel, Joann

    2015-01-01

    The purpose of this research was to characterize the use of simulation in initial paramedic education programs in order assist stakeholders' efforts to target educational initiatives and resources. This group sought to provide a snapshot of what simulation resources programs have or have access to and how they are used; faculty perceptions about simulation; whether program characteristics, resources, or faculty training influence simulation use; and if simulation resources are uniform for patients of all ages. This was a cross-sectional census survey of paramedic programs that were accredited or had a Letter of Review from the Committee on Accreditation of Educational Programs for the EMS Professions at the time of the study. The data were analyzed using descriptive statistics and chi-square analyses. Of the 638 surveys sent, 389 valid responses (61%) were analyzed. Paramedic programs reported they have or have access to a wide range of simulation resources (task trainers [100%], simple manikins [100%], intermediate manikins [99%], advanced/fully programmable manikins [91%], live simulated patients [83%], computer-based [71%], and virtual reality [19%]); however, they do not consistently use them, particularly advanced (71%), live simulated patients (66%), computer-based (games, scenarios) (31%), and virtual reality (4%). Simulation equipment (of any type) reportedly sits idle and unused in (31%) of programs. Lack of training was cited as the most common reason. Personnel support specific to simulation was available in 44% of programs. Programs reported using simulation to replace skills more frequently than to replace field or clinical hours. Simulation goals included assessment, critical thinking, and problem-solving most frequently, and patient and crew safety least often. Programs using advanced manikins report manufacturers as their primary means of training (87%) and that 19% of faculty had no training specific to those manikins. Many (78%) respondents felt

  11. Laparoscopic skills acquisition: a study of simulation and traditional training.

    Science.gov (United States)

    Marlow, Nicholas; Altree, Meryl; Babidge, Wendy; Field, John; Hewett, Peter; Maddern, Guy J

    2014-12-01

    Training in basic laparoscopic skills can be undertaken using traditional methods, where trainees are educated by experienced surgeons through a process of graduated responsibility or by simulation-based training. This study aimed to assess whether simulation trained individuals reach the same level of proficiency in basic laparoscopic skills as traditional trained participants when assessed in a simulated environment. A prospective study was undertaken. Participants were allocated to one of two cohorts according to surgical experience. Participants from the inexperienced cohort were randomized to receive training in basic laparoscopic skills on either a box trainer or a virtual reality simulator. They were then assessed on the simulator on which they did not receive training. Participants from the experienced cohort, considered to have received traditional training in basic laparoscopic skills, did not receive simulation training and were randomized to either the box trainer or virtual reality simulator for skills assessment. The assessment scores from different cohorts on either simulator were then compared. A total of 138 participants completed the assessment session, 101 in the inexperienced simulation-trained cohort and 37 on the experienced traditionally trained cohort. There was no statistically significant difference between the training outcomes of simulation and traditionally trained participants, irrespective of the simulator type used. The results demonstrated that participants trained on either a box trainer or virtual reality simulator achieved a level of basic laparoscopic skills assessed in a simulated environment that was not significantly different from participants who had been traditionally trained in basic laparoscopic skills. © 2013 Royal Australasian College of Surgeons.

  12. Dropout during a driving simulator study: A survival analysis.

    Science.gov (United States)

    Matas, Nicole A; Nettelbeck, Ted; Burns, Nicholas R

    2015-12-01

    Simulator sickness is the occurrence of motion-sickness like symptoms that can occur during use of simulators and virtual reality technologies. This study investigated individual factors that contributed to simulator sickness and dropout while using a desktop driving simulator. Eighty-eight older adult drivers (mean age 72.82±5.42years) attempted a practice drive and two test drives. Participants also completed a battery of cognitive and visual assessments, provided information on their health and driving habits, and reported their experience of simulator sickness symptoms throughout the study. Fifty-two participants dropped out before completing the driving tasks. A time-dependent Cox Proportional Hazards model showed that female gender (HR=2.02), prior motion sickness history (HR=2.22), and Mini-SSQ score (HR=1.55) were associated with dropout. There were no differences between dropouts and completers on any of the cognitive abilities tests. Older adults are a high-risk group for simulator sickness. Within this group, female gender and prior motion sickness history are related to simulator dropout. Higher reported experience of symptoms of simulator sickness increased rates of dropout. The results highlight the importance of screening and monitoring of participants in driving simulation studies. Older adults, females, and those with a prior history of motion sickness may be especially at risk. Copyright © 2015 Elsevier Ltd and National Safety Council. All rights reserved.

  13. Simulation studies for the evaluation of health information technologies

    DEFF Research Database (Denmark)

    Ammenwerth, Elske; Hackl, Werner; Binzer, Kristine

    2012-01-01

    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 drugrelated 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...

  14. Simulation in an Undergraduate Nursing Pharmacology Course: A Pilot Study.

    Science.gov (United States)

    Tinnon, Elizabeth; Newton, Rebecca

    This study examined the effectiveness of simulation as a method of teaching pharmacological concepts to nursing students; perceptions of satisfaction with simulation as a teaching strategy were also evaluated. Second-semester juniors participated in three simulations and completed the National League for Nursing Student Satisfaction and Self-Confidence in Learning Questionnaire and the Student Evaluation of Educational Quality Survey; a control group received traditional lectures. A unit exam on anticoagulant therapy content was administered to measure effectiveness. Findings support that simulation is as effective as traditional lecture for an undergraduate pharmacology course.

  15. Empirical study of parallel LRU simulation algorithms

    Science.gov (United States)

    Carr, Eric; Nicol, David M.

    1994-01-01

    This paper reports on the performance of five parallel algorithms for simulating a fully associative cache operating under the LRU (Least-Recently-Used) replacement policy. Three of the algorithms are SIMD, and are implemented on the MasPar MP-2 architecture. Two other algorithms are parallelizations of an efficient serial algorithm on the Intel Paragon. One SIMD algorithm is quite simple, but its cost is linear in the cache size. The two other SIMD algorithm are more complex, but have costs that are independent on the cache size. Both the second and third SIMD algorithms compute all stack distances; the second SIMD algorithm is completely general, whereas the third SIMD algorithm presumes and takes advantage of bounds on the range of reference tags. Both MIMD algorithm implemented on the Paragon are general and compute all stack distances; they differ in one step that may affect their respective scalability. We assess the strengths and weaknesses of these algorithms as a function of problem size and characteristics, and compare their performance on traces derived from execution of three SPEC benchmark programs.

  16. Simulations

    CERN Document Server

    Ngada, Narcisse

    2015-06-15

    The complexity and cost of building and running high-power electrical systems make the use of simulations unavoidable. The simulations available today provide great understanding about how systems really operate. This paper helps the reader to gain an insight into simulation in the field of power converters for particle accelerators. Starting with the definition and basic principles of simulation, two simulation types, as well as their leading tools, are presented: analog and numerical simulations. Some practical applications of each simulation type are also considered. The final conclusion then summarizes the main important items to keep in mind before opting for a simulation tool or before performing a simulation.

  17. Simulation and the Development of Clinical Judgment: A Quantitative Study

    Science.gov (United States)

    Holland, Susan

    2015-01-01

    The purpose of this quantitative pretest posttest quasi-experimental research study was to explore the effect of the NESD on clinical judgment in associate degree nursing students and compare the differences between groups when the Nursing Education Simulation Design (NESD) guided simulation in order to identify educational strategies promoting…

  18. Realization of a simulator for radon-222 underground migration studies

    International Nuclear Information System (INIS)

    Tidjani, A.; Seidel, J.L.; Monnin, M.; Isabelle, D.B.

    1987-01-01

    To study under controlled conditions the underground movements of radon gas a simulator has been built. It was designed in order to vary independently the different geophysical parameters such as pressure, temperature, humidity, type of soil and its granulometry, etc.. The first tests, described in this paper, have demonstrated the usefullness of such a simulator. (orig.)

  19. Simulation model for studying low frequency microinstabilities

    International Nuclear Information System (INIS)

    Lee, W.W.; Okuda, H.

    1976-03-01

    A 2 1 / 2 dimensional, electrostatic particle code in a slab geometry has been developed to study low frequency oscillations such as drift wave and trapped particle instabilities in a nonuniform bounded plasma. A drift approximation for the electron transverse motion is made which eliminates the high frequency oscillations at the electron gyrofrequency and its multiples. It is, therefore, possible to study the nonlinear effects such as the anomalous transport of plasmas within a reasonable computing time using a real mass ratio. Several examples are given to check the validity and usefulness of the model

  20. Simulation study of the beam-beam interaction at SPEAR

    International Nuclear Information System (INIS)

    Tennyson, J.

    1980-01-01

    A two dimensional simulation study of the beam-beam interaction at SPEAR indicates that quantum fluctuations affecting the horizontal betatron oscillation play a critical role in the vertical beam blowup

  1. Theoretical and simulation studies of seeding methods

    Energy Technology Data Exchange (ETDEWEB)

    Pellegrini, Claudio [Univ. of California, Los Angeles, CA (United States)

    2017-12-11

    We report the theoretical and experimental studies done with the support of DOE-Grant DE-SC0009983 to increase an X-ray FEL peak power from the present level of 20 to 40 GW to one or more TW by seeding, undulator tapering and using the new concept of the Double Bunch FEL.

  2. Simulation studies for charmed baryons production

    International Nuclear Information System (INIS)

    Garcia, Fernanda Gallinucci; Escobar, Carlos O.

    1994-01-01

    Multiparticle soft production is a dominant characteristic in most of high energy hadron collision. Processes with many particles at the final state are intrinsically complicated, since too many variables are involved. Nevertheless, it would be possible to utilize the QCD Lagrangian for studying these soft processes, which do not involve large transferred momenta and therefore, the strong coupling constant α s is to much large for using. Consequently, non-perturbative procedures must be adopted. Presently, when describing the soft hadron physics, it is advisable to build models incorporating all the available ideas, motivated by both QCD non-perturbative studies and the S-matrix general properties (duality and unitarity). A non-perturbative approach presently studied consists in N -1 expansions, where N can be either the color number N c or the N f flavor number. This expansion provides a topological diagram classification. A model which has been very successful in the light particle production is the Quark Gluon String Model. This model uses the Pomerons quark-gluon strings idea for describing the multiple production of hadrons with low p t at high energies

  3. In-hospital resuscitation evaluated by in situ simulation: a prospective simulation study

    DEFF Research Database (Denmark)

    Mondrup, Frederik; Brabrand, Mikkel; Folkestad, Lars

    2011-01-01

    , and to examine differences in the resuscitation performance between the first responders and the cardiac arrest team. METHOD: S: A prospective observational study of 16 unannounced simulated cardiopulmonary arrest scenarios was conducted. The participants of the study involved all health care personel on duty...

  4. A Study on Guide Sign Validity in Driving Simulator

    Directory of Open Access Journals (Sweden)

    Wei Zhonghua

    2011-12-01

    Full Text Available The role of guide sign to inform road user about the information of network is important. How to design and locate guide sign to increase traffic operation efficiency is a key point for traffic engineers. Driving simulator is useful devised to study guide sign in the process and system control. For the purpose of studying guide signs using the tool of driving simulator, guide sign's validity in driving simulator was studied. Results of this experiment are the foundation of further study on guide sign. Simulator calibration procedure for guide sign was set up in this study. Legibility distance as measure of performance was used to evaluate the validity of guide sign in driving simulator. Thirty two participants were recruited. Results indicated legibility distance and speed were inversely related with the method of data mining. Legibility distance and text height of guide sign were positive related. When speed is 20km/h, 30km/h, 40km/h, magnifying power of text height is 4.3, 4.1, 3.8, while guide signs are absolute validity in driving simulator.

  5. Simulation and performance study of ceramic THGEM

    Science.gov (United States)

    Yan, Jia-Qing; Xie, Yu-Guang; Hu, Tao; Lu, Jun-Guang; Zhou, Li; Qu, Guo-Pu; Cai, Xiao; Niu, Shun-Li; Chen, Hai-Tao

    2015-06-01

    THGEMs based on a ceramic substrate have been successfully developed for neutron and single photon detection. The influences on thermal neutron scattering and internal radioactivity of both ceramic and FR-4 substrates were studied and compared. The ceramic THGEMs are homemade, of 200 μm hole diameter, 600 μm pitch, 200 μm thickness, 80 μm rim, and 50 mm×50 mm sensitive area. FR-4 THGEMs with the same geometry were used as a reference. The gas gain, energy resolution and gain stability were measured in different gas mixtures using 5.9 keV X-rays. The maximum gain of a single layer ceramic THGEM reaches 6×104 and 1.5×104 at Ne+CH4=95:5 and Ar + i-C4H10 = 97:3, respectively. The energy resolution is better than 24%. Good gain stability was obtained during a more than 100 hour continuous test in Ar+CO2 = 80:20. By using a 239Pu source, the alpha deposited energy spectrum and gain curve of the ceramic THGEM were measured. Supported by National Natural Science Foundation of China (11205173) and State Key Laboratory of Particle Detection and Electronics (H9294206TD)

  6. Nuclear power plant diagnostics study at the Midland training simulator

    International Nuclear Information System (INIS)

    Reifman, J.; Rank, P.; Lee, J.C.

    1991-01-01

    Training simulators provide a real world environment for testing advanced diagnostic and control systems as an aid to nuclear power plant operators. The simulators not only duplicate the hardware din the actual control room, allowing for analysis of man-machine interface, but also represent the dynamic behavior of the reference plant in real-time, in a realistic manner. Training simulators provide the means to representing the reference plant operations in a wide range of operation conditions including off-normal and emergency conditions. Transient events with very low probability of occurrence can then be represented and used to test the capabilities of advanced diagnostic and control systems. For these reasons, full-scope operator training simulators have been used as a test bed for a number of advanced diagnostic concepts. The University of Michigan and Consumers Power Company have been collaborating in a program devoted to the development and study of advanced concepts for automatic diagnostics and control of nuclear power plants. The program has been focused on the use of the full-scope operator training Midland Nuclear Power Plant Unit 2 (MNP-2) Simulator for development, testing, and verification of advanced diagnostics concepts. In their current efforts, the authors have developed two artificial intelligent (AI) diagnostic concepts that have been applied to the MNP-2 Simulator: the systematic generation and updating of a rule-based knowledge system for nuclear power plant diagnostics and a nonlinear parameter estimation algorithm called the simulation filter. The simulation filter algorithm is used with the MNP-2 Simulator to improve the simulation of the Three Mile Island Unit 2 (TMI-2) accident. 11 refs., 4 figs

  7. Study on a computerized compact simulator of NHR-200

    International Nuclear Information System (INIS)

    Gao Zuying; Dong Yujie

    1997-01-01

    A fully computerized compact simulator is studied in accordance with the engineering practical need of NHR-200. A SUN SPARC 2 stand-alone workstation is selected as its computer system and multi-task structure of software is employed. Simulation program is derived from the RETRAN-02 code. The standard I/O devices are used as its interface equipment and the man-machine interface graphic program is coded on the basis of X Window System. Shared memory and semaphores are used for inter-task communication and a timer is used in real-time control of tasks. Its accuracy and simulation speed are verified by using several typical accident transients. The accuracy and speed are perfectly able to meet the requirements of engineering simulation. It is useful for normal and accident transient analysis, engineering study and design, reactor operation support and personnel training

  8. MODELING SIMULATION AND PERFORMANCE STUDY OF GRIDCONNECTED PHOTOVOLTAIC ENERGY SYSTEM

    OpenAIRE

    Nagendra K; Karthik J; Keerthi Rao C; Kumar Raja Pemmadi

    2017-01-01

    This paper presents Modeling Simulation of grid connected Photovoltaic Energy System and performance study using MATLAB/Simulink. The Photovoltaic energy system is considered in three main parts PV Model, Power conditioning System and Grid interface. The Photovoltaic Model is inter-connected with grid through full scale power electronic devices. The simulation is conducted on the PV energy system at normal temperature and at constant load by using MATLAB.

  9. Virtual reality simulation training of mastoidectomy - studies on novice performance.

    Science.gov (United States)

    Andersen, Steven Arild Wuyts

    2016-08-01

    Virtual reality (VR) simulation-based training is increasingly used in surgical technical skills training including in temporal bone surgery. The potential of VR simulation in enabling high-quality surgical training is great and VR simulation allows high-stakes and complex procedures such as mastoidectomy to be trained repeatedly, independent of patients and surgical tutors, outside traditional learning environments such as the OR or the temporal bone lab, and with fewer of the constraints of traditional training. This thesis aims to increase the evidence-base of VR simulation training of mastoidectomy and, by studying the final-product performances of novices, investigates the transfer of skills to the current gold-standard training modality of cadaveric dissection, the effect of different practice conditions and simulator-integrated tutoring on performance and retention of skills, and the role of directed, self-regulated learning. Technical skills in mastoidectomy were transferable from the VR simulation environment to cadaveric dissection with significant improvement in performance after directed, self-regulated training in the VR temporal bone simulator. Distributed practice led to a better learning outcome and more consolidated skills than massed practice and also resulted in a more consistent performance after three months of non-practice. Simulator-integrated tutoring accelerated the initial learning curve but also caused over-reliance on tutoring, which resulted in a drop in performance when the simulator-integrated tutor-function was discontinued. The learning curves were highly individual but often plateaued early and at an inadequate level, which related to issues concerning both the procedure and the VR simulator, over-reliance on the tutor function and poor self-assessment skills. Future simulator-integrated automated assessment could potentially resolve some of these issues and provide trainees with both feedback during the procedure and immediate

  10. Study of plasticity in metals by numerical simulations

    International Nuclear Information System (INIS)

    Clouet, E.

    2013-01-01

    We present a study of the plastic behaviour in metals based on the modelling of dislocation properties. Different simulation tools have been used and developed to study plasticity in structural materials, in particular metals used in the nuclear industry. In iron or zirconium alloys, plasticity is controlled at low temperature by the glide of screw dislocations. Atomistic simulations can be used to model dislocation core properties and thus to obtain a better knowledge of the mechanisms controlling dislocation glide. Such atomistic simulations need nevertheless some special care because of the long range elastic field induced by the dislocations. We have therefore developed a modelling approach relying both on atomistic simulations, using either empirical interatomic potentials or ab initio calculations, and on elasticity theory. Such an approach has been used to obtain dislocation intrinsic core properties. These simulations allowed us to describe, in iron, the variations of these core properties with the dislocation character. In zirconium, we could identity the origin of the high lattice friction and obtain a better understanding of the competition between the different glide systems. At high temperature, dislocations do not only glide but can also cross-slip or climb. This leads to a motion of the dislocations out of their glide plane which needs to be considered when modelling the plastic flow. We performed a study of dislocation climb at different scales, leading to the implementation of a dislocation climb model in dislocation dynamics simulations. (author) [fr

  11. Virtual Gaming Simulation in Nursing Education: A Focus Group Study.

    Science.gov (United States)

    Verkuyl, Margaret; Hughes, Michelle; Tsui, Joyce; Betts, Lorraine; St-Amant, Oona; Lapum, Jennifer L

    2017-05-01

    The use of serious gaming in a virtual world is a novel pedagogical approach in nursing education. A virtual gaming simulation was implemented in a health assessment class that focused on mental health and interpersonal violence. The study's purpose was to explore students' experiences of the virtual gaming simulation. Three focus groups were conducted with a convenience sample of 20 first-year nursing students after they completed the virtual gaming simulation. Analysis yielded five themes: (a) Experiential Learning, (b) The Learning Process, (c) Personal Versus Professional, (d) Self-Efficacy, and (e) Knowledge. Virtual gaming simulation can provide experiential learning opportunities that promote engagement and allow learners to acquire and apply new knowledge while practicing skills in a safe and realistic environment. [J Nurs Educ. 2017;56(5):274-280.]. Copyright 2017, SLACK Incorporated.

  12. The Simulation Study of Horizontal Axis Water Turbine Using Flow Simulation Solidworks Application

    Science.gov (United States)

    Prasetyo, H.; Budiana, EP; Tjahjana, DDDP; Hadi, S.

    2018-02-01

    The design of Horizontal Axis Water Turbine in pico hydro power plants involves many parameters. To simplify that, usually using computer simulation is applied. This research performs simulation process variation on turbine blade number, turbine blade curvature angle, turbine bucket angle and blocking system tilt angle. Those four variations were combined in order to obtain the best design of turbine. The study used Flow Simulation Solidworks application, and obtain data on turbine speed, pressure, force, and torque. However, this research focused on turbine torque value. The best design of turbine was obtained in the turbine with 6 blades, blade curvature angle of 65° and bucket angle of 10°, and blocking system tilt angle of 40°. In the best turbine, the produced torque value was 8.464 Nm.

  13. Computer simulation studies in condensed-matter physics 5. Proceedings

    International Nuclear Information System (INIS)

    Landau, D.P.; Mon, K.K.; Schuettler, H.B.

    1993-01-01

    As the role of computer simulations began to increase in importance, we sensed a need for a ''meeting place'' for both experienced simulators and neophytes to discuss new techniques and results in an environment which promotes extended discussion. As a consequence of these concerns, The Center for Simulational Physics established an annual workshop on Recent Developments in Computer Simulation Studies in Condensed-Matter Physics. This year's workshop was the fifth in this series and the interest which the scientific community has shown demonstrates quite clearly the useful purpose which the series has served. The workshop was held at the University of Georgia, February 17-21, 1992, and these proceedings from a record of the workshop which is published with the goal of timely dissemination of the papers to a wider audience. The proceedings are divided into four parts. The first part contains invited papers which deal with simulational studies of classical systems and includes an introduction to some new simulation techniques and special purpose computers as well. A separate section of the proceedings is devoted to invited papers on quantum systems including new results for strongly correlated electron and quantum spin models. The third section is comprised of a single, invited description of a newly developed software shell designed for running parallel programs. The contributed presentations comprise the final chapter. (orig.). 79 figs

  14. Study on the CFD simulation of refrigerated container

    Science.gov (United States)

    Arif Budiyanto, Muhammad; Shinoda, Takeshi; Nasruddin

    2017-10-01

    The objective this study is to performed Computational Fluid Dynamic (CFD) simulation of refrigerated container in the container port. Refrigerated container is a thermal cargo container constructed from an insulation wall to carry kind of perishable goods. CFD simulation was carried out use cross sectional of container walls to predict surface temperatures of refrigerated container and to estimate its cooling load. The simulation model is based on the solution of the partial differential equations governing the fluid flow and heat transfer processes. The physical model of heat-transfer processes considered in this simulation are consist of solar radiation from the sun, heat conduction on the container walls, heat convection on the container surfaces and thermal radiation among the solid surfaces. The validation of simulation model was assessed uses surface temperatures at center points on each container walls obtained from the measurement experimentation in the previous study. The results shows the surface temperatures of simulation model has good agreement with the measurement data on all container walls.

  15. Human factors in resuscitation: Lessons learned from simulator studies

    Directory of Open Access Journals (Sweden)

    Hunziker S

    2010-01-01

    Full Text Available Medical algorithms, technical skills, and repeated training are the classical cornerstones for successful cardiopulmonary resuscitation (CPR. Increasing evidence suggests that human factors, including team interaction, communication, and leadership, also influence the performance of CPR. Guidelines, however, do not yet include these human factors, partly because of the difficulties of their measurement in real-life cardiac arrest. Recently, clinical studies of cardiac arrest scenarios with high-fidelity video-assisted simulations have provided opportunities to better delineate the influence of human factors on resuscitation team performance. This review focuses on evidence from simulator studies that focus on human factors and their influence on the performance of resuscitation teams. Similar to studies in real patients, simulated cardiac arrest scenarios revealed many unnecessary interruptions of CPR as well as significant delays in defibrillation. These studies also showed that human factors play a major role in these shortcomings and that the medical performance depends on the quality of leadership and team-structuring. Moreover, simulated video-taped medical emergencies revealed that a substantial part of information transfer during communication is erroneous. Understanding the impact of human factors on the performance of a complex medical intervention like resuscitation requires detailed, second-by-second, analysis of factors involving the patient, resuscitative equipment such as the defibrillator, and all team members. Thus, high-fidelity simulator studies provide an important research method in this challenging field.

  16. Automated simulation and study of spatial-structural design processes

    NARCIS (Netherlands)

    Davila Delgado, J.M.; Hofmeyer, H.; Stouffs, R.; Sariyildiz, S.

    2013-01-01

    A so-called "Design Process Investigation toolbox" (DPI toolbox), has been developed. It is a set of computational tools that simulate spatial-structural design processes. Its objectives are to study spatial-structural design processes and to support the involved actors. Two case-studies are

  17. Framework for Architecture Trade Study Using MBSE and Performance Simulation

    Science.gov (United States)

    Ryan, Jessica; Sarkani, Shahram; Mazzuchim, Thomas

    2012-01-01

    Increasing complexity in modern systems as well as cost and schedule constraints require a new paradigm of system engineering to fulfill stakeholder needs. Challenges facing efficient trade studies include poor tool interoperability, lack of simulation coordination (design parameters) and requirements flowdown. A recent trend toward Model Based System Engineering (MBSE) includes flexible architecture definition, program documentation, requirements traceability and system engineering reuse. As a new domain MBSE still lacks governing standards and commonly accepted frameworks. This paper proposes a framework for efficient architecture definition using MBSE in conjunction with Domain Specific simulation to evaluate trade studies. A general framework is provided followed with a specific example including a method for designing a trade study, defining candidate architectures, planning simulations to fulfill requirements and finally a weighted decision analysis to optimize system objectives.

  18. Dark Energy Studies with LSST Image Simulations, Final Report

    International Nuclear Information System (INIS)

    Peterson, John Russell

    2016-01-01

    This grant funded the development and dissemination of the Photon Simulator (PhoSim) for the purpose of studying dark energy at high precision with the upcoming Large Synoptic Survey Telescope (LSST) astronomical survey. The work was in collaboration with the LSST Dark Energy Science Collaboration (DESC). Several detailed physics improvements were made in the optics, atmosphere, and sensor, a number of validation studies were performed, and a significant number of usability features were implemented. Future work in DESC will use PhoSim as the image simulation tool for data challenges used by the analysis groups.

  19. A simulation study comparing aberration detection algorithms for syndromic surveillance

    Directory of Open Access Journals (Sweden)

    Painter Ian

    2007-03-01

    Full Text Available Abstract Background The usefulness of syndromic surveillance for early outbreak detection depends in part on effective statistical aberration detection. However, few published studies have compared different detection algorithms on identical data. In the largest simulation study conducted to date, we compared the performance of six aberration detection algorithms on simulated outbreaks superimposed on authentic syndromic surveillance data. Methods We compared three control-chart-based statistics, two exponential weighted moving averages, and a generalized linear model. We simulated 310 unique outbreak signals, and added these to actual daily counts of four syndromes monitored by Public Health – Seattle and King County's syndromic surveillance system. We compared the sensitivity of the six algorithms at detecting these simulated outbreaks at a fixed alert rate of 0.01. Results Stratified by baseline or by outbreak distribution, duration, or size, the generalized linear model was more sensitive than the other algorithms and detected 54% (95% CI = 52%–56% of the simulated epidemics when run at an alert rate of 0.01. However, all of the algorithms had poor sensitivity, particularly for outbreaks that did not begin with a surge of cases. Conclusion When tested on county-level data aggregated across age groups, these algorithms often did not perform well in detecting signals other than large, rapid increases in case counts relative to baseline levels.

  20. Team play in surgical education: a simulation-based study.

    Science.gov (United States)

    Marr, Mollie; Hemmert, Keith; Nguyen, Andrew H; Combs, Ronnie; Annamalai, Alagappan; Miller, George; Pachter, H Leon; Turner, James; Rifkind, Kenneth; Cohen, Steven M

    2012-01-01

    Simulation-based training provides a low-stress learning environment where real-life emergencies can be practiced. Simulation can improve surgical education and patient care in crisis situations through a team approach emphasizing interpersonal and communication skills. This study assessed the effects of simulation-based training in the context of trauma resuscitation in teams of trainees. In a New York State-certified level I trauma center, trauma alerts were assessed by a standardized video review process. Simulation training was provided in various trauma situations followed by a debriefing period. The outcomes measured included the number of healthcare workers involved in the resuscitation, the percentage of healthcare workers in role position, time to intubation, time to intubation from paralysis, time to obtain first imaging study, time to leave trauma bay for computed tomography scan or the operating room, presence of team leader, and presence of spinal stabilization. Thirty cases were video analyzed presimulation and postsimulation training. The two data sets were compared via a 1-sided t test for significance (p role positions increased from 57.8% to 83.6% (p = 0.46). The time to intubation from paralysis decreased from 3.9 to 2.8 minutes (p team leader increased from 64% to 90% (p team interaction and educational competencies. Providing simulation training as a tool for surgical education may enhance patient care. Copyright © 2012 Association of Program Directors in Surgery. Published by Elsevier Inc. All rights reserved.

  1. Study, simulation and design of a 3D clinostat

    Science.gov (United States)

    Pavone, Valentina; Guarnieri, Vincenzo; Lobascio, Cesare; Soma, Aurelio; Bosso, Nicola; Lamantea, Matteo Maria

    High cost and limited number of physically executable experiments in space have introduced the need for ground simulation systems that enable preparing experiments to be carried out on board, identifying phenomena associated with the altered gravity conditions, and taking advantage of these conditions, as in Biotechnology. Among systems developed to simulate microgravity, especially for life sciences experiments, different types of clinostats were realized. This work deals with mechanical design of a three-dimensional clinostat and simulation of the dynamic behavior of the system by varying the operating parameters. The design and simulation phase was preceded by a careful analysis of the state of art and by the review of the most recent results, in particular from the major investigators of Life Sciences in Space. The mechanical design is quite innovative by adoption of a structure entirely in aluminum, which allows robustness while reducing the overall weight. The transmission system of motion has been optimized by means of brushless DC micro motors, light and compact, which helped to reduce weight, dimensions, power consumption and increase the reliability and durability of the system. The study of the dynamic behavior using SIMPACK, a multibody simulation software, led to results in line with those found in the most important and recent scientific publications. This model was also appropriately configured to represent any desired operating condition, and for eventual system scalability. It would be interesting to generate simulated hypogravity - e.g.: 0.38-g (Mars) or 0.17-g (Moon). This would allow to investigate how terrestrial life forms can grow in other planetary habitats, or to determine the gravity threshold response of different organisms. At the moment, such a system can only be achieved by centrifuges in real microgravity. We are confident that simulation and associated tests with our 3D clinostat can help adjusting the parameters allowing variable g

  2. Breeding for Welfare in outdoor pig production : simulation study

    NARCIS (Netherlands)

    Gourdine, J.L.; Greef, de K.H.; Rydhmer, L.

    2010-01-01

    Despite the societal and market attention, to our knowledge, there is no breeding program for outdoor pig production in which improvement in animal welfare is emphasized. In this study, a dam-line selected for an outdoor production system was simulated. The purpose was to investigate the

  3. Influence of roadside infrastructure on driving behavior: driving simulator study

    NARCIS (Netherlands)

    Horst, A.R.A. van der; Ridder, S. de

    2007-01-01

    This paper describes the results of a driving simulator study that focused on the influence of roadside infrastructure on speed choice and lateral placement of car drivers. A review of the RISER detailed accident database revealed that lateral positioning and speed of the vehicle were two of the

  4. Improving clinical practice through simulation: A case study of ...

    African Journals Online (AJOL)

    Acquisition of knowledge and skills by nursing students before real-life practice is a familiar nursing education challenge. The use of clinical simulation in nursing education provides many opportunities for students to learn and apply theoretical principles of nursing care in a safe environment. The purpose of this study was ...

  5. Comparative Study of the Simulated and Calculation Gantry Angle ...

    African Journals Online (AJOL)

    Breast irradiation involves a complex geometric and field-matching technique. Simulators are used to obtain the best and accurate patient treatment positioning as well as irradiation geometry for radiation portals. However many centers in developing countries lack this important equipment. The study was designed to ...

  6. A simulation based engineering method to support HAZOP studies

    DEFF Research Database (Denmark)

    Enemark-Rasmussen, Rasmus; Cameron, David; Angelo, Per Bagge

    2012-01-01

    the conventional HAZOP procedure. The method systematically generates failure scenarios by considering process equipment deviations with pre-defined failure modes. The effect of failure scenarios is then evaluated using dynamic simulations -in this study the K-Spice® software used. The consequences of each failure...

  7. A study of pleasantness and annoyance in simulated soundscapes

    DEFF Research Database (Denmark)

    Alvarez, Jorge; Konstantinos, Angelakis; Rindel, Jens Holger

    2006-01-01

    An experimental study has been conducted in the Acoustic Technology Department of the Technical University of Denmark. Audio-visual simulations of a park and an urban square were attempted; a series of listening tests were carried out. The subjects were asked to qualify the soundscape in terms...

  8. School Leadership and Administration: Important Concepts, Case Studies and Simulations

    Science.gov (United States)

    Gorton, Richard; Alston, Judy; Snowden, Petra

    2006-01-01

    This text helps prospective and experienced principals, administrators, and supervisors increase their knowledge and skills through concepts, case-studies, and simulations. This book contains the following two parts and fifteen chapters. Part I presents important theoretical concepts and research findings that can improve educators'…

  9. A Nanoscale Simulation Study of Elastic Properties of Gaspeite

    Directory of Open Access Journals (Sweden)

    Benazzouz Brahim-Khalil

    2015-02-01

    Full Text Available The study of structural and mechanical properties of carbonate rock is an interesting subject in engineering and its different applications. In this paper, the crystal structure of gaspeite (NiCO3 is investigated by carrying out molecular dynamics simulations based on energy minimization technique using an interatomic interaction potential.

  10. The organisation of transactions : studying supply networkd using gaming simulation

    NARCIS (Netherlands)

    Meijer, S.A.

    2009-01-01

    This book studies the organisation of transactions in supply networks. More specifically it investigates the influence of social structure on the mode of organisation in supply networks. To gain new insights, the results in this book have been gathered using gaming simulation as a research method.

  11. Cognitive distance, absorptive capacity and group rationality : a simulation study

    NARCIS (Netherlands)

    Curseu, P.L.; Krehel, O.; Evers, J.H.M.; Muntean, A.

    2014-01-01

    We report the results of a simulation study in which we explore the joint effect of group absorptive capacity (as the average individual rationality of the group members) and cognitive distance (as the distance between the most rational group member and the rest of the group) on the emergence of

  12. Cognitive distance, absorptive capacity and group rationality : A simulation study

    NARCIS (Netherlands)

    Curseu, P.L.; Krehel, O.; Evers, J.H.M.; Muntean, A.

    2014-01-01

    We report the results of a simulation study in which we explore the joint effect of group absorptive capacity (as the average individual rationality of the group members) and cognitive distance (as the distance between the most rational group member and the rest of the group) on the emergence of

  13. Sequential Computerized Mastery Tests--Three Simulation Studies

    Science.gov (United States)

    Wiberg, Marie

    2006-01-01

    A simulation study of a sequential computerized mastery test is carried out with items modeled with the 3 parameter logistic item response theory model. The examinees' responses are either identically distributed, not identically distributed, or not identically distributed together with estimation errors in the item characteristics. The…

  14. Simulation study of an automated storage/retrieval system

    NARCIS (Netherlands)

    Berg, van den J.P.; Gademann, A.J.R.M.

    2000-01-01

    In this paper we present a simulation study of an automated storage/retrieval system and examine a wide variety of control policies. We compare several storage location assignment policies. For the class-based storage policy, we apply a recent algorithm that enables us to evaluate the trade-off

  15. RTS amplitudes in decananometer MOSFETs: 3-D simulation study

    OpenAIRE

    Asenov, A.; Balasubramaniam, R.; Brown, A.R.; Davies, J.H.

    2003-01-01

    In this paper we study the amplitudes of random telegraph signals (RTS) associated with the trapping of a single electron in defect states at the Si/SiO/sub 2/ interface of sub-100-nm (decananometer) MOSFETs employing three-dimensional (3-D) "atomistic" simulations. Both continuous doping charge and random discrete dopants in the active region of the MOSFETs are considered in the simulations. The dependence of the RTS amplitudes on the position of the trapped charge in the channel and on devi...

  16. Planetary Simulation Chambers bring Mars to laboratory studies

    Energy Technology Data Exchange (ETDEWEB)

    Mateo-Marti, E.

    2016-07-01

    Although space missions provide fundamental and unique knowledge for planetary exploration, they are always costly and extremely time-consuming. Due to the obvious technical and economical limitations of in-situ planetary exploration, laboratory simulations are among the most feasible research options for making advances in planetary exploration. Therefore, laboratory simulations of planetary environments are a necessary and complementary option to expensive space missions. Simulation chambers are economical, more versatile, and allow for a higher number of experiments than space missions. Laboratory-based facilities are able to mimic the conditions found in the atmospheres and on the surfaces of a majority of planetary objects. Number of relevant applications in Mars planetary exploration will be described in order to provide an understanding about the potential and flexibility of planetary simulation chambers systems: mainly, stability and presence of certain minerals on Mars surface; and microorganisms potential habitability under planetary environmental conditions would be studied. Therefore, simulation chambers will be a promising tools and necessary platform to design future planetary space mission and to validate in-situ measurements from orbital or rover observations. (Author)

  17. Simulation Study of a Vehicle Production Line for Productivity Improvement

    Directory of Open Access Journals (Sweden)

    M.F.F. Ab Rashid

    2015-06-01

    Full Text Available This paper presents the study of a motorcycle frame production line in a particular company in Malaysia. Due to the high demand, the company needs to increase its production by at least 12% compared with current output. In order to improve productivity, the production-floor data was collected and simulated using the discrete event simulation approach. Later, a number of suggestions for improvement were simulated to identify the effect of the suggestions on productivity. In addition, cost analysis was also undertaken to identify the profit margin for a particular period of time for each suggestion. Simulation results indicate that there are three suggestions that are able to fulfill the 12% volume increment. In the short term, the suggestion to hire an assistant line leader will give instant effect to the profit. Meanwhile, for the medium term, Poka-yoke will give higher profit compared with the others, while in the long term, SOP (standard operating procedure implementation will yield a better profit margin. In future, the simulation of a dynamic demand model for this product is suggested to cope with new trends in the market.

  18. Study of asymmetrical electric discharges using particle simulation

    International Nuclear Information System (INIS)

    Alves, M.V.

    1990-11-01

    Asymmetrical electric discharges are been widely used in the microelectronic industry. The asymmetry in the electrode areas determines the magnitude of the plasma-to-electrode voltage, V sub(a), at the powered electrode, which determines the ion bombarding energy, a critical plasma processing parameter. Two many-particle simulation codes, called P D C 1 and P D S 1, were developed. These codes are electrostatic, one-dimensional (radial) and model (a bounded plasma between two infinite cylinders or two concentric spheres that can be connected to a RLC external circuit. Both codes consider asymmetrical electrodes areas. In order to simulate electrical discharges, Monte-Carlo simulation of electron-neutral and ion-neutral collisions were included. These codes were used to study the relationship between the voltage area ratio across the sheaths, V sub(a) / V sub(b), and the electrode area ratio A sub(b) / A sub(a). Simulation results agree with experimental results and also with the analytical model that includes local ionization near the electrodes, observed to occur in almost all our simulations. (author)

  19. Self-Radiolysis of Tritiated Water: Experimental Study and Simulation

    International Nuclear Information System (INIS)

    Heinze, Sylver; Stolz, Thibaut; Ducret, Didier; Colson, Jean-Claude

    2005-01-01

    Radioactive decay of tritium contained in tritiated water leads to the production of gaseous helium and, through self-radiolysis, to the formation of molecular hydrogen and oxygen. For safety management of tritiated water storage, it is essential to be able to predict pressure increase resulting from this phenomenon. The present study aims to identify the mechanisms that take place in self-radiolysis of chemically pure liquid tritiated water. The evolution of the concentration of hydrogen and oxygen in the gas phase of closed vessels containing tritiated water has been followed experimentally. Simulation of pure water radiolysis has been carried out using data from the literature. In order to fit experimental results, simulation should take into account gas phase recombination reaction between hydrogen and oxygen. A simplified system has been extracted from the complete chemical system used to simulate radiolysis. This system allows identifying the basic mechanisms that are responsible for tritiated water self-radiolysis

  20. Quench detection, protection and simulation studies on SST-1 magnets

    International Nuclear Information System (INIS)

    Sharma, Aashoo N.; Khristi, Yohan; Pradhan, Subrata; Doshi, Kalpesh; Prasad, Upendra; Banaudha, Moni; Varmora, Pankaj; Praghi, Bhadresh R.

    2015-01-01

    Steady-state Superconducting Tokamak-1 (SST-1) is India's first tokamak with superconducting toroidal field (TF) and Poloidal Field (PF) magnets. These magnets are made with NbTi based Cable-In-Conduit-Conductors. The quench characteristic of SST-1 CICC has been extensively studied both analytically and using simulation codes. Dedicated experiments like model coil test program, TF coil test program and laboratory experiments were conducted to fully characterize the performance of the CICC and the magnets made using this CICC. Results of quench experiments performed during these tests have been used to design the SST-1 quench detection and protection system. Simulation results of TF coil quenches and slow propagation quench of TF busbars have been used to further optimize these systems during the SST-1 tokamak operation. Redundant hydraulic based quench detection is also proposed for the TF coil quench detection. This paper will give the overview of these development and simulation activities. (author)

  1. Realistic electricity market simulator for energy and economic studies

    International Nuclear Information System (INIS)

    Bernal-Agustin, Jose L.; Contreras, Javier; Conejo, Antonio J.; Martin-Flores, Raul

    2007-01-01

    Electricity market simulators have become a useful tool to train engineers in the power industry. With the maturing of electricity markets throughout the world, there is a need for sophisticated software tools that can replicate the actual behavior of power markets. In most of these markets, power producers/consumers submit production/demand bids and the Market Operator clears the market producing a single price per hour. What makes markets different from each other are the bidding rules and the clearing algorithms to balance the market. This paper presents a realistic simulator of the day-ahead electricity market of mainland Spain. All the rules that govern this market are modeled. This simulator can be used either to train employees by power companies or to teach electricity markets courses in universities. To illustrate the tool, several realistic case studies are presented and discussed. (author)

  2. Studies on defect evolution in steels: experiments and computer simulations

    International Nuclear Information System (INIS)

    Sundar, C.S.

    2011-01-01

    In this paper, we present the results of our on-going studies on steels that are being carried out with a view to develop radiation resistant steels. The focus is on the use of nano-dispersoids in alloys towards the suppression of void formation and eventual swelling under irradiation. Results on the nucleation and growth of TiC precipitates in Ti modified austenitic steels and investigations on nano Yttria particles in Fe - a model oxide dispersion ferritic steel will be presented. The experimental methods of ion beam irradiation and positron annihilation spectroscopy have been used to elucidate the role of minor alloying elements on swelling behaviour. Computer simulation of defect processes have been carried out using ab-initio methods, molecular dynamics and Monte Carlo simulations. Our perspectives on addressing the multi-scale phenomena of defect processes leading to radiation damage, through a judicious combination of experiments and simulations, would be presented. (author)

  3. Challenging stereotyping and bias: a voice simulation study.

    Science.gov (United States)

    Dearing, Karen S; Steadman, Sheryl

    2008-02-01

    Stigma is a barrier to mental health care access for patients with schizophrenia and can interfere with developing therapeutic relationships. This study demonstrates success of a voice simulation experience during orientation in changing the biases of nursing students and the effect on the development of the nurse-patient relationship. Ninety-four individuals participated; 52 received a voice simulation experience during orientation, and 42 received orientation with no voice simulation experience. The Medical Condition Regard Scale was administered before and after orientation. Posttest paired t test results show significant differences in attitudes toward patients with voice hearing experiences between the two groups. The themes of personal growth from the focus groups postorientation include Affective Experience, Physical Experience, and Empathy. Findings demonstrate that the orientation process should include methods to challenge stereotyping and bias to decrease stigma, improve service access, and enhance the ability to develop therapeutic relationships.

  4. Mathematical and computational modeling and simulation fundamentals and case studies

    CERN Document Server

    Moeller, Dietmar P F

    2004-01-01

    Mathematical and Computational Modeling and Simulation - a highly multi-disciplinary field with ubiquitous applications in science and engineering - is one of the key enabling technologies of the 21st century. This book introduces to the use of Mathematical and Computational Modeling and Simulation in order to develop an understanding of the solution characteristics of a broad class of real-world problems. The relevant basic and advanced methodologies are explained in detail, with special emphasis on ill-defined problems. Some 15 simulation systems are presented on the language and the logical level. Moreover, the reader can accumulate experience by studying a wide variety of case studies. The latter are briefly described within the book but their full versions as well as some simulation software demos are available on the Web. The book can be used for University courses of different level as well as for self-study. Advanced sections are marked and can be skipped in a first reading or in undergraduate courses...

  5. A simulated regolith medium for multi-wavelength studies

    Science.gov (United States)

    Wilkman, O.; Muinonen, K.; Parviainen, H.; Näränen, J.

    2012-04-01

    Effects arising from the small-scale surface structure are significant in remote studies of regolith surfaces on atmosphereless solar system bodies, such as the Moon, Mercury and the asteroids. The important properties determining these effects are the porosity of the regolith and the roughness of the interface between the bulk material and empty space. We concentrate on the regolith effects in visible light photometry and X-ray spectrometry. The fluorescent X-ray spectrum induced by solar X-rays contains information about the elemental abundances of the surface material, while the photometry can be used to constrain surface properties such as porosity. We have developed a computer model simulating a regolith medium consisting of spherical particles with variable size distribution and properties. The bulk properties of the medium, such as porosity and surface roughness, can be varied. The model can then be used in ray-tracing simulations of the regolith effects in both visible light scattering and X-ray fluorescence. In photometric studies the scattering law of the constituent particles can be chosen to take into account scattering phenomena such as coherent backscattering. In the X-ray simulations, we can choose the elemental abundances of the material and the spectrum of the incident X-ray radiation. The ray-tracing simulations then allow us to determine the characteristics of the emitted radiation in different observational geometries. We present results from various studies which have been based on our regolith model. The model has been used to simulate the regolith effects on X-ray fluorescence spectra under specific situations. These can be compared to laboratory measurements. The visible light simulations have been applied in a study of the shadowing effects in photometry. The model was also used in a study of lunar photometry from SMART-1/AMIE data. Applications in the analysis of X-ray spectrometry from the BepiColombo MIXS/SIXS instruments are planned. An

  6. Simulation

    DEFF Research Database (Denmark)

    Gould, Derek A; Chalmers, Nicholas; Johnson, Sheena J

    2012-01-01

    Recognition of the many limitations of traditional apprenticeship training is driving new approaches to learning medical procedural skills. Among simulation technologies and methods available today, computer-based systems are topical and bring the benefits of automated, repeatable, and reliable p...... performance assessments. Human factors research is central to simulator model development that is relevant to real-world imaging-guided interventional tasks and to the credentialing programs in which it would be used....

  7. Simulations to study the static polarization limit for RHIC lattice

    Science.gov (United States)

    Duan, Zhe; Qin, Qing

    2016-01-01

    A study of spin dynamics based on simulations with the Polymorphic Tracking Code (PTC) is reported, exploring the dependence of the static polarization limit on various beam parameters and lattice settings for a practical RHIC lattice. It is shown that the behavior of the static polarization limit is dominantly affected by the vertical motion, while the effect of beam-beam interaction is small. In addition, the “nonresonant beam polarization” observed and studied in the lattice-independent model is also observed in this lattice-dependent model. Therefore, this simulation study gives insights of polarization evolution at fixed beam energies, that are not available in simple spin tracking. Supported by the U.S. Department of Energy (DE-AC02-98CH10886), Hundred-Talent Program (Chinese Academy of Sciences), and National Natural Science Foundation of China (11105164)

  8. MHD simulation study of compact toroid injection into magnetized plasmas

    International Nuclear Information System (INIS)

    Suzuki, Yoshio; Kishimoto, Yasuaki

    2000-01-01

    To understand the fuelling process in a fusion device by a compact toroid (CT) plasmoid injection method, we have carried out MHD numerical simulations where a spheromak-like CT (SCT) is injected into a magnetized target plasma region. So far, we revealed that the penetration depth of the SCT plasma becomes shorter than that estimated from the conducting sphere (CS) model, because in the simulation the Lorentz force of the target magnetic field sequentially decelerates the injected SCT while in the CS model only the magnetic pressure force acts as the deceleration mechanism. In this study, we represent the new theoretical model where the injected SCT is decelerated by both the magnetic pressure force and the magnetic tension force (we call it the non-slipping sphere (NS) model) and investigate in detail the deceleration mechanism of the SCT by comparison with simulation results. As a result, it is found that the decrease of the SCT kinetic energy in the simulation coincides with that in the NS model more than in the CS model. It means that not only the magnetic pressure force but also the magnetic tension force acts as the deceleration mechanism of the SCT. Furthermore, it is revealed that magnetic reconnection between the SCT magnetic field and the target magnetic field plays a role to relax the SCT deceleration. (author)

  9. Study of TXRF experimental system by Monte Carlo simulation

    International Nuclear Information System (INIS)

    Costa, Ana Cristina M.; Leitao, Roberta G.; Lopes, Ricardo T.; Anjos, Marcelino J.; Conti, Claudio C.

    2011-01-01

    The Total-Reflection X-ray Fluorescence (TXRF) technique offers unique possibilities to study the concentrations of a wide range of trace elements in various types of samples. Besides that, the TXRF technique is widely used to study the trace elements in biological, medical and environmental samples due to its multielemental character as well as simplicity of sample preparation and quantification methods used. In general the TXRF experimental setup is not simple and might require substantial experimental efforts. On the other hand, in recent years, experimental TXRF portable systems have been developed. It has motivated us to develop our own TXRF portable system. In this work we presented a first step in order to optimize a TXRF experimental setup using Monte Carlo simulation by MCNP code. The results found show that the Monte Carlo simulation method can be used to investigate the development of a TXRF experimental system before its assembly. (author)

  10. The TESS [Tandem Experiment Simulation Studies] computer code user's manual

    International Nuclear Information System (INIS)

    Procassini, R.J.

    1990-01-01

    TESS (Tandem Experiment Simulation Studies) is a one-dimensional, bounded particle-in-cell (PIC) simulation code designed to investigate the confinement and transport of plasma in a magnetic mirror device, including tandem mirror configurations. Mirror plasmas may be modeled in a system which includes an applied magnetic field and/or a self-consistent or applied electrostatic potential. The PIC code TESS is similar to the PIC code DIPSI (Direct Implicit Plasma Surface Interactions) which is designed to study plasma transport to and interaction with a solid surface. The codes TESS and DIPSI are direct descendants of the PIC code ES1 that was created by A. B. Langdon. This document provides the user with a brief description of the methods used in the code and a tutorial on the use of the code. 10 refs., 2 tabs

  11. The Advanced Gamma-ray Imaging System (AGIS): Simulation Studies

    Science.gov (United States)

    Fegan, Stephen; Buckley, J. H.; Bugaev, S.; Funk, S.; Konopelko, A.; Maier, G.; Vassiliev, V. V.; Simulation Studies Working Group; AGIS Collaboration

    2008-03-01

    The Advanced Gamma-ray Imaging System (AGIS) is a concept for the next generation instrument in ground-based very high energy gamma-ray astronomy. It has the goal of achieving significant improvement in sensitivity over current experiments. We present the results of simulation studies of various possible designs for AGIS. The primary characteristics of the array performance, collecting area, angular resolution, background rejection, and sensitivity are discussed.

  12. The Advanced Gamma-ray Imaging System (AGIS): Simulation Studies

    OpenAIRE

    Maier, G.; Collaboration, for the AGIS

    2009-01-01

    The Advanced Gamma-ray Imaging System (AGIS) is a next-generation ground-based gamma-ray observatory being planned in the U.S. The anticipated sensitivity of AGIS is about one order of magnitude better than the sensitivity of current observatories, allowing it to measure gammaray emmission from a large number of Galactic and extra-galactic sources. We present here results of simulation studies of various possible designs for AGIS. The primary characteristics of the array performance - collect...

  13. Studying and simulating transformer configuration to improve power quality

    Directory of Open Access Journals (Sweden)

    Oscar J. Peña Huaringa

    2011-06-01

    Full Text Available This paper presents a study and simulation of transformer configurations to improve power quality; it provides theoretical support based on the expansion of the Fourier series and analysis of symmetrical components. A test system was set up in the laboratory, taking measurements and checking configuration effectiveness in reducing the system’s harmonic content. The configurations were modelled with PSCAD / EMTDC software, using two 6 pulse rectifiers as test loads and two variable speed drives.

  14. Simulation study of resonant reflector for S-band BWO

    International Nuclear Information System (INIS)

    Choyal, Y; Parmar, Nidhi; Saini, Ajay Kumar; Chhotray, S K; Bhat, K S; Kumar, Lalit

    2012-01-01

    This paper presents the result of simulation studies of resonant reflector used for reflection of backward wave in relativistic BWO. The resonant reflector is modelled and analyzed by CST MWS for TM 01 . A TM 01 mode is fed at the output end of the BWO and signal is observed at the cathode end. Results show that 90 percent of the backward TM 01 wave is get reflected back by the locked TM 02 mode in the resonant reflector.

  15. A prospective, randomized study addressing the need for physical simulation following virtual simulation

    International Nuclear Information System (INIS)

    Valicenti, Richard K.; Waterman, Frank M.; Corn, Benjamin W.; Curran, Walter J.

    1997-01-01

    Purpose: To accurately implement a treatment plan obtained by virtual or CT simulation, conventional or physical simulation is still widely used. To evaluate the need for physical simulation, we prospectively randomized patients to undergo physical simulation or no additional simulation after virtual simulation. Methods and Materials: From July 1995 to September 1996, 75 patients underwent conformal four-field radiation therapy planning for prostate cancer with a commercial grade CT simulator. The patients were randomized to undergo either port filming immediately following physical simulation or port filming alone. The precision of implementing the devised plan was evaluated by comparing simulator radiographs and/or port films against the digitally reconstructed radiographs (DRRs) for x, y, and z displacements of the isocenter. Changes in beam aperture were also prospectively evaluated. Results: Thirty-seven patients were randomized to undergo physical simulation and first day port filming, and 38 had first day treatment verification films only without a physical simulation. Seventy-eight simulator radiographs and 195 first day treatment port films were reviewed. There was no statistically significant reduction in treatment setup error (>5 mm) if patients underwent physical simulation following virtual simulation. No patient required a resimulation, and there was no significant difference in changes of beam aperture. Conclusions: Following virtual simulation, physical simulation may not be necessary to accurately implement the conformal four-field technique. Because port filming appears to be sufficient to assure precise and reliable execution of a devised treatment plan, physical simulation may be eliminated from the process of CT based planning when virtual simulation is available

  16. Study of Gamma spectra by Monte Carlo simulation

    International Nuclear Information System (INIS)

    Cantaragiu, A.; Gheorghies, A.; Borcia, C.

    2008-01-01

    The purpose of this paper is obtaining gamma ray spectra by means of a scintillation detector applying the Monte Carlo statistic simulation method using the EGS4 program. The Monte Carlo algorithm implies that the physical system is described by the probability density function which allows generating random figures and the result is taken as an average of numbers which were observed. The EGS4 program allows the simulation of the following physical processes: the photo-electrical effect, the Compton effect, the electron positron pairs generation and the Rayleigh diffusion. The gamma rays recorded by the detector are converted into electrical pulses and the gamma ray spectra are acquired and processed by means of the Nomad Plus portable spectrometer connected to a computer. As a gamma ray sources 137Cs and 60Co are used whose spectra drawn and used for study the interaction of the gamma radiations with the scintillation detector. The parameters which varied during the acquisition of the gamma ray spectra are the distance between source and detector and the measuring time. Due to the statistical processes in the detector, the peak looks like a Gauss distribution. The identification of the gamma quantum energy value is achieved by the experimental spectra peaks, thus gathering information about the position of the peak, the width and the area of the peak respectively. By means of the EGS4 program a simulation is run using these parameters and an 'ideal' spectrum is obtained, a spectrum which is not influenced by the statistical processes which take place inside the detector. Then, the convolution of the spectra is achieved by means of a normalised Gauss function. There is a close match between the experimental results and those simulated in the EGS4 program because the interactions which occurred during the simulation have a statistical behaviour close to the real one. (authors)

  17. Study and simulation of a parallel numerical processing machine

    International Nuclear Information System (INIS)

    Bel Hadj, Slaheddine

    1981-12-01

    This study has been carried out in the perspective of the implementation on a minicomputer of the NEPTUNIX package (software for the resolution of very large algebra-differential equation systems). Aiming at increasing the system performance, a previous research work has shown the necessity of reducing the execution time of certain numerical computation tasks, which are of frequent use. It has also demonstrated the feasibility of handling these tasks with efficient algorithms of parallel type. The present work deals with the study and simulation of a parallel architecture processor adapted to the fast execution of these algorithms. A minicomputer fitted with a connection to such a parallel processor, has a greatly extended computing power. Then the architecture of a parallel numerical processor, based on the use of VLSI microprocessors and co-processors, is described. Its design aims at the best cost / performance ratio. The last part deals with the simulation processor with the 'CHAMBOR' program. Results show an increasing factor of 30 in speed, in comparison with the execution on a MITRA 15 minicomputer. Moreover the conflicts importance, mainly at the level of access to a shared resource is evaluated. Although this implementation has been designed having in mind a dedicated application, other uses could be envisaged, particularly for the simulation of nuclear reactors: operator guiding system, the behavioural study under accidental circumstances, etc. (author) [fr

  18. COMPARATIVE STUDY OF TERTIARY WASTEWATER TREATMENT BY COMPUTER SIMULATION

    Directory of Open Access Journals (Sweden)

    Stefania Iordache

    2010-01-01

    Full Text Available The aim of this work is to asses conditions for implementation of a Biological Nutrient Removal (BNR process in theWastewater Treatment Plant (WWTP of Moreni city (Romania. In order to meet the more increased environmentalregulations, the wastewater treatment plant that was studied, must update the actual treatment process and have tomodernize it. A comparative study was undertaken of the quality of effluents that could be obtained by implementationof biological nutrient removal process like A2/O (Anaerobic/Anoxic/Oxic and VIP (Virginia Plant Initiative aswastewater tertiary treatments. In order to asses the efficiency of the proposed treatment schemata based on the datamonitored at the studied WWTP, it were realized computer models of biological nutrient removal configurations basedon A2/O and VIP process. Computer simulation was realized using a well-known simulator, BioWin by EnviroSimAssociates Ltd. The simulation process allowed to obtain some data that can be used in design of a tertiary treatmentstage at Moreni WWTP, in order to increase the efficiency in operation.

  19. Can We Study Autonomous Driving Comfort in Moving-Base Driving Simulators? A Validation Study.

    Science.gov (United States)

    Bellem, Hanna; Klüver, Malte; Schrauf, Michael; Schöner, Hans-Peter; Hecht, Heiko; Krems, Josef F

    2017-05-01

    To lay the basis of studying autonomous driving comfort using driving simulators, we assessed the behavioral validity of two moving-base simulator configurations by contrasting them with a test-track setting. With increasing level of automation, driving comfort becomes increasingly important. Simulators provide a safe environment to study perceived comfort in autonomous driving. To date, however, no studies were conducted in relation to comfort in autonomous driving to determine the extent to which results from simulator studies can be transferred to on-road driving conditions. Participants ( N = 72) experienced six differently parameterized lane-change and deceleration maneuvers and subsequently rated the comfort of each scenario. One group of participants experienced the maneuvers on a test-track setting, whereas two other groups experienced them in one of two moving-base simulator configurations. We could demonstrate relative and absolute validity for one of the two simulator configurations. Subsequent analyses revealed that the validity of the simulator highly depends on the parameterization of the motion system. Moving-base simulation can be a useful research tool to study driving comfort in autonomous vehicles. However, our results point at a preference for subunity scaling factors for both lateral and longitudinal motion cues, which might be explained by an underestimation of speed in virtual environments. In line with previous studies, we recommend lateral- and longitudinal-motion scaling factors of approximately 50% to 60% in order to obtain valid results for both active and passive driving tasks.

  20. Monte Carlo Simulations Validation Study: Vascular Brachytherapy Beta Sources

    International Nuclear Information System (INIS)

    Orion, I.; Koren, K.

    2004-01-01

    During the last decade many versions of angioplasty irradiation treatments have been proposed. The purpose of this unique brachytherapy is to administer a sufficient radiation dose into the vein walls in order to prevent restonosis, a clinical sequel to balloon angioplasty. The most suitable sources for this vascular brachytherapy are the β - emitters such as Re-188, P-32, and Sr-90/Y-90, with a maximum energy range of up to 2.1 MeV [1,2,3]. The radioactive catheters configurations offered for these treatments can be a simple wire [4], a fluid filled balloon or a coated stent. Each source is differently positioned inside the blood vessel, and the emitted electrons ranges therefore vary. Many types of sources and configurations were studied either experimentally or with the use of the Monte Carlo calculation technique, while most of the Monte Carlo simulations were carried out using EGS4 [5] or MCNP [6]. In this study we compared the beta-source absorbed-dose versus radial-distance of two treatment configurations using MCNP and EGS4 simulations. This comparison was aimed to discover the differences between the MCNP and the EGS4 simulation code systems in intermediate energies electron transport

  1. Leading teams during simulated pediatric emergencies: a pilot study

    Science.gov (United States)

    Coolen, Ester H; Draaisma, Jos M; den Hamer, Sabien; Loeffen, Jan L

    2015-01-01

    Purpose Leadership has been identified as a key variable for the functioning of teams and as one of the main reasons for success or failure of team-based work systems. Pediatricians often function as team leaders in the resuscitation of a critically ill child. However, pediatric residents often report having little opportunity to perform in the role of team leader during residency. In order to gain more insight into leadership skills and behaviors, we classified leadership styles of pediatric residents during simulated emergencies. Methods We conducted a prospective quantitative study to investigate leadership styles used by pediatric residents during simulated emergencies with clinical deterioration of a child at a pediatric ward. Using videotaped scenarios of 48 simulated critical events among 12 residents, we were able to classify verbal and nonverbal communication into different leadership styles according to the situational leadership theory. Results The coaching style (mean 54.5%, SD 7.8) is the most frequently applied by residents, followed by the directing style (mean 35.6%, SD 4.1). This pattern conforms to the task- and role-related requirements in our scenarios and it also conforms to the concept of situational leadership. We did not find any significant differences in leadership style according to the postgraduate year or scenario content. Conclusion The model used in this pilot study helps us to gain a better understanding of the development of effective leadership behavior and supports the applicability of situational leadership theory in training leadership skills during residency. PMID:25610010

  2. Simulation and experimental study of resin flow in fibre fabrics

    Science.gov (United States)

    Yan, Fei; Yan, Shilin; Li, Yongjing

    2017-06-01

    Liquid Composite Moulding (LCM) is gradually becoming the most competitive manufacturing technology for producing large composite parts with complex geometry with high quality and low cost. These parts include those for airplanes, wind turbine blades and automobile components. Fibre fabrics in liquid composite moulding can be considered as dual-scale porous media. In different gap scales, an unsaturated flow is produced during the mould filling process. This particular flow behaviour deviates from the traditional Darcy’s law, which is used to calculate the filling pressure and will cause errors. According to sink theory, the unsaturated flow characteristics of this dual-scale porous media were studied in this paper, and a FEM solution program was developed. The results showed that the pressure curves against the position which simulated by sink functions were departure from the position of traditional theory. In addition, the simulation results of partially-saturated region were consistent with the experimental data.

  3. Study on cementation of simulated radioactive borated liquid wastes

    International Nuclear Information System (INIS)

    Sun Qina; Li Junfeng; Wang Jianlong

    2010-01-01

    To compare sulfoaluminate cement with ordinary Portland cement on their cementation of radioactive borated liquid waste and to provide more data for formula optimization, simulated radioactive borated liquid waste were solidified by the two cements. 28 d compressive strength and strength losses after water/freezing/irradiation resistance tests were investigated. Leaching test and X-ray diffraction analysis were also conducted. The results show that it is feasible to solidify borated liquid wastes with sulfoaluminate cement and ordinary Portland cement with formulas used in the study. The 28 d compressive strengths, strength losses after tests and simulated nuclides leaching rates of the solidified waste forms meet the demand of GB 14569.1-93. The sulfoaluminate cement formula show better retention of Cs + than ordinary Portland cement formula. Boron, in form of B (OH) 4 - , incorporate in ettringite as solid solutions. (authors)

  4. Simulation study of secondary electron images in scanning ion microscopy

    CERN Document Server

    Ohya, K

    2003-01-01

    The target atomic number, Z sub 2 , dependence of secondary electron yield is simulated by applying a Monte Carlo code for 17 species of metals bombarded by Ga ions and electrons in order to study the contrast difference between scanning ion microscopes (SIM) and scanning electron microscopes (SEM). In addition to the remarkable reversal of the Z sub 2 dependence between the Ga ion and electron bombardment, a fine structure, which is correlated to the density of the conduction band electrons in the metal, is calculated for both. The brightness changes of the secondary electron images in SIM and SEM are simulated using Au and Al surfaces adjacent to each other. The results indicate that the image contrast in SIM is much more sensitive to the material species and is clearer than that for SEM. The origin of the difference between SIM and SEM comes from the difference in the lateral distribution of secondary electrons excited within the escape depth.

  5. Simulation studies of emittance growth in RMS mismatched beams

    International Nuclear Information System (INIS)

    Cucchetti, A.; Wangler, T.; Reiser, M.

    1991-01-01

    As shown in a separate paper, a charged-particle beam, whose rms size is not matched when injected into a transport channel or accelerator, has excess energy compared with that of a matched beam. If nonlinear space-charge forces are present and the mismatched beam transforms to a matched equilibrium state, rms-emittance growth will occur. The theory yields formulas for the possible rms-emittance growth, but not for the time it takes to achieve this growth. In this paper we present the results of systematic simulation studies for a mismatched 2-D round beam in an ideal transport channel with continuous linear focusing. Emittance growth rates obtained from the simulations for different amounts of mismatch and initial charge will be presented and the emittance growth will be compared with the theory. 6 refs., 7 figs

  6. AUV-Based Plume Tracking: A Simulation Study

    Directory of Open Access Journals (Sweden)

    Awantha Jayasiri

    2016-01-01

    Full Text Available This paper presents a simulation study of an autonomous underwater vehicle (AUV navigation system operating in a GPS-denied environment. The AUV navigation method makes use of underwater transponder positioning and requires only one transponder. A multirate unscented Kalman filter is used to determine the AUV orientation and position by fusing high-rate sensor data and low-rate information. The paper also proposes a gradient-based, efficient, and adaptive novel algorithm for plume boundary tracking missions. The algorithm follows a centralized approach and it includes path optimization features based on gradient information. The proposed algorithm is implemented in simulation on the AUV-based navigation system and successful boundary tracking results are obtained.

  7. Plasma environment of Titan: a 3-D hybrid simulation study

    Directory of Open Access Journals (Sweden)

    S. Simon

    2006-05-01

    Full Text Available Titan possesses a dense atmosphere, consisting mainly of molecular nitrogen. Titan's orbit is located within the Saturnian magnetosphere most of the time, where the corotating plasma flow is super-Alfvénic, yet subsonic and submagnetosonic. Since Titan does not possess a significant intrinsic magnetic field, the incident plasma interacts directly with the atmosphere and ionosphere. Due to the characteristic length scales of the interaction region being comparable to the ion gyroradii in the vicinity of Titan, magnetohydrodynamic models can only offer a rough description of Titan's interaction with the corotating magnetospheric plasma flow. For this reason, Titan's plasma environment has been studied by using a 3-D hybrid simulation code, treating the electrons as a massless, charge-neutralizing fluid, whereas a completely kinetic approach is used to cover ion dynamics. The calculations are performed on a curvilinear simulation grid which is adapted to the spherical geometry of the obstacle. In the model, Titan's dayside ionosphere is mainly generated by solar UV radiation; hence, the local ion production rate depends on the solar zenith angle. Because the Titan interaction features the possibility of having the densest ionosphere located on a face not aligned with the ram flow of the magnetospheric plasma, a variety of different scenarios can be studied. The simulations show the formation of a strong magnetic draping pattern and an extended pick-up region, being highly asymmetric with respect to the direction of the convective electric field. In general, the mechanism giving rise to these structures exhibits similarities to the interaction of the ionospheres of Mars and Venus with the supersonic solar wind. The simulation results are in agreement with data from recent Cassini flybys.

  8. Leading teams during simulated pediatric emergencies: a pilot study

    Directory of Open Access Journals (Sweden)

    Coolen EH

    2015-01-01

    Full Text Available Ester H Coolen,1 Jos M Draaisma,2 Sabien den Hamer,3 Jan L Loeffen2 1Department of Pediatric Surgery, Amalia Children’s Hospital, Radboud University Medical Center, 2Department of Pediatrics, Amalia Children’s Hospital, Radboud University Medical Center, 3Department of Communication Science, Radboud University, Nijmegen, the Netherlands Purpose: Leadership has been identified as a key variable for the functioning of teams and as one of the main reasons for success or failure of team-based work systems. Pediatricians often function as team leaders in the resuscitation of a critically ill child. However, pediatric residents often report having little opportunity to perform in the role of team leader during residency. In order to gain more insight into leadership skills and behaviors, we classified leadership styles of pediatric residents during simulated emergencies. Methods: We conducted a prospective quantitative study to investigate leadership styles used by pediatric residents during simulated emergencies with clinical deterioration of a child at a pediatric ward. Using videotaped scenarios of 48 simulated critical events among 12 residents, we were able to classify verbal and nonverbal communication into different leadership styles according to the situational leadership theory. Results: The coaching style (mean 54.5%, SD 7.8 is the most frequently applied by residents, followed by the directing style (mean 35.6%, SD 4.1. This pattern conforms to the task- and role-related requirements in our scenarios and it also conforms to the concept of situational leadership. We did not find any significant differences in leadership style according to the postgraduate year or scenario content. Conclusion: The model used in this pilot study helps us to gain a better understanding of the development of effective leadership behavior and supports the applicability of situational leadership theory in training leadership skills during residency. Keywords

  9. Study on advancement of in vivo counting using mathematical simulation

    Energy Technology Data Exchange (ETDEWEB)

    Kinase, Sakae [Japan Atomic Energy Research Inst., Tokai, Ibaraki (Japan). Tokai Research Establishment

    2003-05-01

    To obtain an assessment of the committed effective dose, individual monitoring for the estimation of intakes of radionuclides is required. For individual monitoring of exposure to intakes of radionuclides, direct measurement of radionuclides in the body - in vivo counting- is very useful. To advance in a precision in vivo counting which fulfills the requirements of ICRP 1990 recommendations, some problems, such as the investigation of uncertainties in estimates of body burdens by in vivo counting, and the selection of the way to improve the precision, have been studied. In the present study, a calibration technique for in vivo counting application using Monte Carlo simulation was developed. The advantage of the technique is that counting efficiency can be obtained for various shapes and sizes that are very difficult to change for phantoms. To validate the calibration technique, the response functions and counting efficiencies of a whole-body counter installed in JAERI were evaluated using the simulation and measurements. Consequently, the calculations are in good agreement with the measurements. The method for the determination of counting efficiency curves as a function of energy was developed using the present technique and a physiques correction equation was derived from the relationship between parameters of correction factor and counting efficiencies of the JAERI whole-body counter. The uncertainties in body burdens of {sup 137}Cs estimated with the JAERI whole-body counter were also investigated using the Monte Carlo simulation and measurements. It was found that the uncertainties of body burdens estimated with the whole-body counter are strongly dependent on various sources of uncertainty such as radioactivity distribution within the body and counting statistics. Furthermore, the evaluation method of the peak efficiencies of a Ge semi-conductor detector was developed by Monte Carlo simulation for optimum arrangement of Ge semi-conductor detectors for

  10. Plasma environment of Titan: a 3-D hybrid simulation study

    Directory of Open Access Journals (Sweden)

    S. Simon

    2006-05-01

    Full Text Available Titan possesses a dense atmosphere, consisting mainly of molecular nitrogen. Titan's orbit is located within the Saturnian magnetosphere most of the time, where the corotating plasma flow is super-Alfvénic, yet subsonic and submagnetosonic. Since Titan does not possess a significant intrinsic magnetic field, the incident plasma interacts directly with the atmosphere and ionosphere. Due to the characteristic length scales of the interaction region being comparable to the ion gyroradii in the vicinity of Titan, magnetohydrodynamic models can only offer a rough description of Titan's interaction with the corotating magnetospheric plasma flow. For this reason, Titan's plasma environment has been studied by using a 3-D hybrid simulation code, treating the electrons as a massless, charge-neutralizing fluid, whereas a completely kinetic approach is used to cover ion dynamics. The calculations are performed on a curvilinear simulation grid which is adapted to the spherical geometry of the obstacle. In the model, Titan's dayside ionosphere is mainly generated by solar UV radiation; hence, the local ion production rate depends on the solar zenith angle. Because the Titan interaction features the possibility of having the densest ionosphere located on a face not aligned with the ram flow of the magnetospheric plasma, a variety of different scenarios can be studied. The simulations show the formation of a strong magnetic draping pattern and an extended pick-up region, being highly asymmetric with respect to the direction of the convective electric field. In general, the mechanism giving rise to these structures exhibits similarities to the interaction of the ionospheres of Mars and Venus with the supersonic solar wind. The simulation results are in agreement with data from recent Cassini flybys.

  11. Using DOE Commercial Reference Buildings for Simulation Studies: Preprint

    Energy Technology Data Exchange (ETDEWEB)

    Field, K.; Deru, M.; Studer, D.

    2010-08-01

    The U.S. Department of Energy developed 256 EnergyPlus models for use in studies that aim to characterize about 70% of the U.S. commercial building stock. Sixteen building types - including restaurants, health care, schools, offices, supermarkets, retail, lodging, and warehouses - are modeled across 16 cities to represent the diversity of U.S. climate zones. Weighting factors have been developed to combine the models in proportions similar to those of the McGraw-Hill Construction Projects Starts Database for 2003-2007. This paper reviews the development and contents of these models and their applications in simulation studies.

  12. Energy flux simulation in heterogeneous cropland - a two year study

    Science.gov (United States)

    Klein, Christian; Thieme, Christoph; Biernath, Christian; Heinlein, Florian; Priesack, Eckart

    2016-04-01

    Recent studies show that uncertainties in regional and global climate and weather simulations are partly due to inadequate descriptions of the energy flux exchanges between the land surface and the atmosphere [Stainforth et al. 2005]. One major shortcoming is the limitation of the grid-cell resolution, which is recommended to be about at least 3x3 km² in most models due to limitations in the model physics. To represent each individual grid cell most models select one dominant soil type and one dominant land use type. This resolution, however, is often too coarse in regions where the spatial heterogeneity of soil and land use types are high, e.g. in Central Europe. The relevance of vegetation (e.g. crops), ground cover, and soil properties to the moisture and energy exchanges between the land surface and the atmosphere is well known [McPherson 2007], but the impact of vegetation growth dynamics on energy fluxes is only partly understood [Gayler et al. 2014]. An elegant method to avoid the shortcoming of grid cell resolution is the so called mosaic approach. This approach is part of the recently developed ecosystem model framework Expert-N [Biernath et al. 2013] . The aim of this study was to analyze the impact of the characteristics of five managed field plots, planted with winter wheat, potato and maize on the near surface soil moistures and on the near surface energy flux exchanges of the soil-plant-atmosphere interface. The simulated energy fluxes were compared with eddy flux tower measurements between the respective fields at the research farm Scheyern, North-West of Munich, Germany. To perform these simulations, we coupled the ecosystem model Expert-N to an analytical footprint model [Mauder & Foken 2011] . The coupled model system has the ability to calculate the mixing ratio of the surface energy fluxes at a given point within one grid cell (in this case at the flux tower between the two fields). The approach accounts for the temporarily and spatially

  13. Quantum mechanical simulation methods for studying biological systems

    International Nuclear Information System (INIS)

    Bicout, D.; Field, M.

    1996-01-01

    Most known biological mechanisms can be explained using fundamental laws of physics and chemistry and a full understanding of biological processes requires a multidisciplinary approach in which all the tools of biology, chemistry and physics are employed. An area of research becoming increasingly important is the theoretical study of biological macromolecules where numerical experimentation plays a double role of establishing a link between theoretical models and predictions and allowing a quantitative comparison between experiments and models. This workshop brought researchers working on different aspects of the development and application of quantum mechanical simulation together, assessed the state-of-the-art in the field and highlighted directions for future research. Fourteen lectures (theoretical courses and specialized seminars) deal with following themes: 1) quantum mechanical calculations of large systems, 2) ab initio molecular dynamics where the calculation of the wavefunction and hence the energy and forces on the atoms for a system at a single nuclear configuration are combined with classical molecular dynamics algorithms in order to perform simulations which use a quantum mechanical potential energy surface, 3) quantum dynamical simulations, electron and proton transfer processes in proteins and in solutions and finally, 4) free seminars that helped to enlarge the scope of the workshop. (N.T.)

  14. Experimental study and simulations of infiltration in evapotranspiration landfill covers

    Directory of Open Access Journals (Sweden)

    Wen-xian Zhang

    2009-09-01

    Full Text Available Various cover systems have been designed for landfill sites in order to minimize infiltration (percolation into the underlying waste. This study evaluated the soil water balance performance of evapotranspiration covers (ET covers and simulated percolation in the systems using the active region model (ARM. Experiments were conducted to measure water flow processes and water balance components in a bare soil cover and different ET covers. Results showed that vegetation played a critical role in controlling the water balance of the ET covers. In soil profiles of 60-cm depth with and without vegetation cover, the maximum soil water storage capacities were 97.2 mm and 62.8 mm, respectively. The percolation amount in the bare soil was 2.1 times that in the vegetation-covered soil. The ARM simulated percolation more accurately than the continuum model because it considered preferential flow. Numerical simulation results also indicated that using the ET cover system was an effective way of removing water through evapotranspiration, thus reducing percolation.

  15. Experiment and Simulation Study on the Amorphous Silicon Photovoltaic Walls

    Directory of Open Access Journals (Sweden)

    Wenjie Zhang

    2014-01-01

    Full Text Available Based on comparative study on two amorphous silicon photovoltaic walls (a-Si PV walls, the temperature distribution and the instant power were tested; and with EnergyPlus software, similar models of the walls were built to simulate annual power generation and air conditioning load. On typical sunshine day, the corresponding position temperature of nonventilated PV wall was generally 0.5~1.5°C higher than that of ventilated one, while the power generation was 0.2%~0.4% lower, which was consistent with the simulation results with a difference of 0.41% in annual energy output. As simulation results, in summer, comparing the PV walls with normal wall, the heat per unit area of these two photovoltaic walls was 5.25 kWh/m2 (nonventilated and 0.67 kWh/m2 (ventilated higher, respectively. But in winter the heat loss of nonventilated one was smaller, while ventilated PV wall was similar to normal wall. To annual energy consumption of heating and cooling, the building with ventilated PV wall and normal wall was also similar but slightly better than nonventilated one. Therefore, it is inferred that, at low latitudes, such as Zhuhai, China, air gap ventilation is suitable, while the length to thickness ratio of the air gap needs to be taken into account.

  16. Simulation Study on the Controllable Dielectrophoresis Parameters of Graphene

    Science.gov (United States)

    Ji, Jian-Long; Liu, Ya-Li; Ge, Yang; Xie, Sheng-Dong; Zhang, Xi; Sang, Sheng-Bo; Jian, Ao-Qun; Duan, Qian-Qian; Zhang, Qiang; Zhang, Wen-Dong

    2017-03-01

    The method of using dielectrophoresis (DEP) to assemble graphene between micro-electrodes has been proven to be simple and efficient. We present an optimization method for the kinetic formula of graphene DEP, and discuss the simulation of the graphene assembly process based on the finite element method. The simulated results illustrate that the accelerated motion of graphene is in agreement with the distribution of the electric field squared gradient. We also conduct research on the controllable parameters of the DEP assembly such as the alternating current (AC) frequency, the shape of micro-electrodes, and the ratio of the gap between electrodes to the characteristic/geometric length of graphene (λ). The simulations based on the Clausius-Mossotti factor reveal that both graphene velocity and direction are influenced by the AC frequency. When graphene is close to the electrodes, the shape of micro-electrodes will exert great influence on the velocity of graphene. Also, λ has a great influence on the velocity of graphene. Generally, the velocity of graphene would be greater when λ is in the range of 0.4-0.6. The study is of a theoretical guiding significance in improving the precision and efficiency of the graphene DEP assembly. Supported by the Basic Research Project of Shanxi Province under Grant No 2015021092, the National Natural Science Foundation of China under Grant Nos 61471255, 61474079, 61501316, 51505324 and 51622507, and the National High-Technology Research and Development Program of China under Grant No 2015AA042601.

  17. Simulation studies on stability of hot electron plasma

    International Nuclear Information System (INIS)

    Ohsawa, Yukiharu

    1985-01-01

    Stability of a hot electron plasma in an NBT(EBT)-like geometry is studied by using a 2-1/2 dimensional relativistic, electromagnetic particle code. For the low-frequency hot electron interchange mode, comparison of the simulation results with the analytical predictions of linear stability theory show fairly good agreement with the magnitude of the growth rates calculated without hot electron finite Larmor radius effects. Strong stabilizing effects by finite Larmor radius of the hot electrons are observed for short wavelength modes. As for the high-frequency hot electron interchange mode, there is a discrepancy between the simulation results and the theory. The high-frequency instability is not observed though a parameter regime is chosen in which the high-frequency hot electron interchange mode is theoretically predicted to grow. Strong cross-field diffusion in a poloidal direction of the hot electrons might explain the stability. Each particle has a magnetic drift velocity, and the speed of the magnetic drift is proportional to the kinetic energy of each particle. Hence, if the particles have high temperature, the spread of the magnetic drift velocity is large. This causes a strong cross-field diffusion of the hot electrons. In the simulation for this interchange mode, an enhanced temperature relaxation is observed between the hot and cold electrons although the theoretically predicted high frequency modes are stable. (Nogami, K.)

  18. Monte Carlo simulations and dosimetric studies of an irradiation facility

    Energy Technology Data Exchange (ETDEWEB)

    Belchior, A. [Instituto Tecnologico e Nuclear, Estrada nacional no. 10, Apartado 21, 2686-953 Sacavem (Portugal)], E-mail: anabelchior@itn.pt; Botelho, M.L; Vaz, P. [Instituto Tecnologico e Nuclear, Estrada nacional no. 10, Apartado 21, 2686-953 Sacavem (Portugal)

    2007-09-21

    There is an increasing utilization of ionizing radiation for industrial applications. Additionally, the radiation technology offers a variety of advantages in areas, such as sterilization and food preservation. For these applications, dosimetric tests are of crucial importance in order to assess the dose distribution throughout the sample being irradiated. The use of Monte Carlo methods and computational tools in support of the assessment of the dose distributions in irradiation facilities can prove to be economically effective, representing savings in the utilization of dosemeters, among other benefits. One of the purposes of this study is the development of a Monte Carlo simulation, using a state-of-the-art computational tool-MCNPX-in order to determine the dose distribution inside an irradiation facility of Cobalt 60. This irradiation facility is currently in operation at the ITN campus and will feature an automation and robotics component, which will allow its remote utilization by an external user, under REEQ/996/BIO/2005 project. The detailed geometrical description of the irradiation facility has been implemented in MCNPX, which features an accurate and full simulation of the electron-photon processes involved. The validation of the simulation results obtained was performed by chemical dosimetry methods, namely a Fricke solution. The Fricke dosimeter is a standard dosimeter and is widely used in radiation processing for calibration purposes.

  19. Studying pressure denaturation of a protein by molecular dynamics simulations.

    Science.gov (United States)

    Sarupria, Sapna; Ghosh, Tuhin; García, Angel E; Garde, Shekhar

    2010-05-15

    Many globular proteins unfold when subjected to several kilobars of hydrostatic pressure. This "unfolding-up-on-squeezing" is counter-intuitive in that one expects mechanical compression of proteins with increasing pressure. Molecular simulations have the potential to provide fundamental understanding of pressure effects on proteins. However, the slow kinetics of unfolding, especially at high pressures, eliminates the possibility of its direct observation by molecular dynamics (MD) simulations. Motivated by experimental results-that pressure denatured states are water-swollen, and theoretical results-that water transfer into hydrophobic contacts becomes favorable with increasing pressure, we employ a water insertion method to generate unfolded states of the protein Staphylococcal Nuclease (Snase). Structural characteristics of these unfolded states-their water-swollen nature, retention of secondary structure, and overall compactness-mimic those observed in experiments. Using conformations of folded and unfolded states, we calculate their partial molar volumes in MD simulations and estimate the pressure-dependent free energy of unfolding. The volume of unfolding of Snase is negative (approximately -60 mL/mol at 1 bar) and is relatively insensitive to pressure, leading to its unfolding in the pressure range of 1500-2000 bars. Interestingly, once the protein is sufficiently water swollen, the partial molar volume of the protein appears to be insensitive to further conformational expansion or unfolding. Specifically, water-swollen structures with relatively low radii of gyration have partial molar volume that are similar to that of significantly more unfolded states. We find that the compressibility change on unfolding is negligible, consistent with experiments. We also analyze hydration shell fluctuations to comment on the hydration contributions to protein compressibility. Our study demonstrates the utility of molecular simulations in estimating volumetric properties

  20. Simulation Based Studies in Software Engineering: A Matter of Validity

    Directory of Open Access Journals (Sweden)

    Breno Bernard Nicolau de França

    2015-04-01

    Full Text Available Despite the possible lack of validity when compared with other science areas, Simulation-Based Studies (SBS in Software Engineering (SE have supported the achievement of some results in the field. However, as it happens with any other sort of experimental study, it is important to identify and deal with threats to validity aiming at increasing their strength and reinforcing results confidence. OBJECTIVE: To identify potential threats to SBS validity in SE and suggest ways to mitigate them. METHOD: To apply qualitative analysis in a dataset resulted from the aggregation of data from a quasi-systematic literature review combined with ad-hoc surveyed information regarding other science areas. RESULTS: The analysis of data extracted from 15 technical papers allowed the identification and classification of 28 different threats to validity concerned with SBS in SE according Cook and Campbell’s categories. Besides, 12 verification and validation procedures applicable to SBS were also analyzed and organized due to their ability to detect these threats to validity. These results were used to make available an improved set of guidelines regarding the planning and reporting of SBS in SE. CONCLUSIONS: Simulation based studies add different threats to validity when compared with traditional studies. They are not well observed and therefore, it is not easy to identify and mitigate all of them without explicit guidance, as the one depicted in this paper.

  1. Operationalising elaboration theory for simulation instruction design: a Delphi study.

    Science.gov (United States)

    Haji, Faizal A; Khan, Rabia; Regehr, Glenn; Ng, Gary; de Ribaupierre, Sandrine; Dubrowski, Adam

    2015-06-01

    The aim of this study was to assess the feasibility of incorporating the Delphi process within the simplifying conditions method (SCM) described in elaboration theory (ET) to identify conditions impacting the complexity of procedural skills for novice learners. We generated an initial list of conditions impacting the complexity of lumbar puncture (LP) from key informant interviews (n = 5) and a literature review. Eighteen clinician-educators from six different medical specialties were subsequently recruited as expert panellists. Over three Delphi rounds, these panellists rated: (i) their agreement with the inclusion of the simple version of the conditions in a representative ('epitome') training scenario, and (ii) how much the inverse (complex) version increases LP complexity for a novice. Cronbach's α-values were used to assess inter-rater agreement. All panellists completed Rounds 1 and 2 of the survey and 17 completed Round 3. In Round 1, Cronbach's α-values were 0.89 and 0.94 for conditions that simplify and increase LP complexity, respectively; both values increased to 0.98 in Rounds 2 and 3. With the exception of 'high CSF (cerebral spinal fluid) pressure', panellists agreed with the inclusion of all conditions in the simplest (epitome) training scenario. Panellists rated patient movement, spinal anatomy, patient cooperativeness, body habitus, and the presence or absence of an experienced assistant as having the greatest impact on the complexity of LP. This study demonstrated the feasibility of using expert consensus to establish conditions impacting the complexity of procedural skills, and the benefits of incorporating the Delphi method into the SCM. These data can be used to develop and sequence simulation scenarios in a progressively challenging manner. If the theorised learning gains associated with ET are realised, the methods described in this study may be applied to the design of simulation training for other procedural and non-procedural skills

  2. Tax amnesties, justice perceptions, and filing behavior: a simulation study.

    Science.gov (United States)

    Rechberger, Silvia; Hartner, Martina; Kirchler, Erich; Hämmerle, Franziska

    2010-04-01

    A simulation study demonstrates the influence of perceived justice of a tax amnesty on subsequent tax compliance. In addition, it investigates how the amnesty is perceived to serve the punishment objectives retribution (i.e., giving offenders what they "deserve") and value restoration (i.e., restoring the values violated by tax evasion). Hierarchical regression analysis revealed the expected positive influence of justice on subsequent tax compliance. However, when the influence of punishment objectives was controlled for, the influence of justice disappeared, while retribution and value restoration showed positive effects on post-amnesty tax compliance.

  3. M3D project for simulation studies of plasmas

    International Nuclear Information System (INIS)

    Park, W.; Belova, E.V.; Fu, G.Y.; Sugiyama, L.E.

    1998-01-01

    The M3D (Multi-level 3D) project carries out simulation studies of plasmas of various regimes using multi-levels of physics, geometry, and mesh schemes in one code package. This paper and papers by Strauss, Sugiyama, and Belova in this workshop describe the project, and present examples of current applications. The currently available physics models of the M3D project are MHD, two-fluids, gyrokinetic hot particle/MHD hybrid, and gyrokinetic particle ion/two-fluid hybrid models. The code can be run with both structured and unstructured meshes

  4. Simulation study of burning control with internal transport barrier

    Energy Technology Data Exchange (ETDEWEB)

    Tateishi, Gonta [Interdisciplinary Graduate School of Engineering Sciences, Kyushu University, Fukuoka (Japan); Yagi, Masatoshi; Itoh, S.I. [Kyushu Univ., Fukuoka (Japan). Research Inst. for Applied Mechanics

    2000-02-01

    Dynamics of burning plasma with internal transport barrier is studied by use of a one dimensional transport simulation code. Two possible mechanisms are modeled for internal transport barrier collapse. One is the collapse, which occurs above the critical pressure gradient, the impact of which is modeled by the enhancement of thermal conductivity. The other is the collapse, which occurs due to the sawtooth trigger. The extended Kadomtsev type reconnection model with multiple resonant surfaces is introduced. Both models are examined for the analysis of long time sustainment of burning. A test of profile control to mitigate the collapse is investigated. The additional circulating power to suppress thermal quench (collapse) is evaluated. (author)

  5. A Monte Carlo simulation study of associated liquid crystals

    Science.gov (United States)

    Berardi, R.; Fehervari, M.; Zannoni, C.

    We have performed a Monte Carlo simulation study of a system of ellipsoidal particles with donor-acceptor sites modelling complementary hydrogen-bonding groups in real molecules. We have considered elongated Gay-Berne particles with terminal interaction sites allowing particles to associate and form dimers. The changes in the phase transitions and in the molecular organization and the interplay between orientational ordering and dimer formation are discussed. Particle flip and dimer moves have been used to increase the convergency rate of the Monte Carlo (MC) Markov chain.

  6. Large Scale Simulation Platform for NODES Validation Study

    Energy Technology Data Exchange (ETDEWEB)

    Sotorrio, P. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Qin, Y. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Min, L. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)

    2017-04-27

    This report summarizes the Large Scale (LS) simulation platform created for the Eaton NODES project. The simulation environment consists of both wholesale market simulator and distribution simulator and includes the CAISO wholesale market model and a PG&E footprint of 25-75 feeders to validate the scalability under a scenario of 33% RPS in California with additional 17% of DERS coming from distribution and customers. The simulator can generate hourly unit commitment, 5-minute economic dispatch, and 4-second AGC regulation signals. The simulator is also capable of simulating greater than 10k individual controllable devices. Simulated DERs include water heaters, EVs, residential and light commercial HVAC/buildings, and residential-level battery storage. Feeder-level voltage regulators and capacitor banks are also simulated for feeder-level real and reactive power management and Vol/Var control.

  7. Comparative Study of the Effectiveness of Three Learning Environments: Hyper-Realistic Virtual Simulations, Traditional Schematic Simulations and Traditional Laboratory

    Science.gov (United States)

    Martinez, Guadalupe; Naranjo, Francisco L.; Perez, Angel L.; Suero, Maria Isabel; Pardo, Pedro J.

    2011-01-01

    This study compared the educational effects of computer simulations developed in a hyper-realistic virtual environment with the educational effects of either traditional schematic simulations or a traditional optics laboratory. The virtual environment was constructed on the basis of Java applets complemented with a photorealistic visual output.…

  8. Parameter uncertainty in simulations of extreme precipitation and attribution studies.

    Science.gov (United States)

    Timmermans, B.; Collins, W. D.; O'Brien, T. A.; Risser, M. D.

    2017-12-01

    The attribution of extreme weather events, such as heavy rainfall, to anthropogenic influence involves the analysis of their probability in simulations of climate. The climate models used however, such as the Community Atmosphere Model (CAM), employ approximate physics that gives rise to "parameter uncertainty"—uncertainty about the most accurate or optimal values of numerical parameters within the model. In particular, approximate parameterisations for convective processes are well known to be influential in the simulation of precipitation extremes. Towards examining the impact of this source of uncertainty on attribution studies, we investigate the importance of components—through their associated tuning parameters—of parameterisations relating to deep and shallow convection, and cloud and aerosol microphysics in CAM. We hypothesise that as numerical resolution is increased the change in proportion of variance induced by perturbed parameters associated with the respective components is consistent with the decreasing applicability of the underlying hydrostatic assumptions. For example, that the relative influence of deep convection should diminish as resolution approaches that where convection can be resolved numerically ( 10 km). We quantify the relationship between the relative proportion of variance induced and numerical resolution by conducting computer experiments that examine precipitation extremes over the contiguous U.S. In order to mitigate the enormous computational burden of running ensembles of long climate simulations, we use variable-resolution CAM and employ both extreme value theory and surrogate modelling techniques ("emulators"). We discuss the implications of the relationship between parameterised convective processes and resolution both in the context of attribution studies and progression towards models that fully resolve convection.

  9. Plasma boundaries at Mars: a 3-D simulation study

    Directory of Open Access Journals (Sweden)

    A. Bößwetter

    2004-12-01

    Full Text Available The interaction of the solar wind with the ionosphere of planet Mars is studied using a three-dimensional hybrid model. Mars has only a weak intrinsic magnetic field, and consequently its ionosphere is directly affected by the solar wind. The gyroradii of the solar wind protons are in the range of several hundred kilometers and therefore comparable with the characteristic scales of the interaction region. Different boundaries emerge from the interaction of the solar wind with the continuously produced ionospheric heavy-ion plasma, which could be identified as a bow shock (BS, ion composition boundary (ICB and magnetic pile up boundary (MPB, where the latter both turn out to coincide. The simulation results regarding the shape and position of these boundaries are in good agreement with the measurements made by Phobos-2 and MGS spacecraft. It is shown that the positions of these boundaries depend essentially on the ionospheric production rate, the solar wind ram pressure, and the often unconsidered electron temperature of the ionospheric heavy ion plasma. Other consequences are rays of planetary plasma in the tail and heavy ion plasma clouds, which are stripped off from the dayside ICB region by some instability.

    Key words. Magnetospheric physics (solar wind interactions with unmagnetized bodies – Space plasma physics (discontinuities; numerical simulation studies

  10. Comparison of classic simulation and virtual simulation in breast irradiation: prospective study on 14 patients

    International Nuclear Information System (INIS)

    Bauduceau, O.; Pons, P.; Romero, L.; Fayolle, M.; Campana, F.; Bollet, M.

    2005-01-01

    Purpose. - To compare conventional 2D simulation and virtual simulation on 14 patients with breast cancer. Patients and methods. - Patients were simulated for treatment using standard procedure. They subsequently underwent CT scan in the treatment position. The CTV was defined as breast tissue. The PTV was obtained by adding a 3D margin of 1 cm around CTV. Organs at risk (lungs and heart) were outlined. Ballistics and dose distribution obtained with the two planning methods were compared. Results. - With conventional simulation, 95% of CTV received 95% of the dose prescribed. Virtual simulation significantly improved dosimetric coverage of PTV without increasing irradiation volume of lung and heart. In 2D simulation, using three slices allowed optimisation by adjusting wedge angle. The five-slice plan was a much better predictor of the maximum dose regions when compared to the three-slice plan. Using entire CT data did not give any benefit. Conclusion. - Variations in CTV delineation and PTV definition limit interest of virtual simulation. In classic simulation, a 5 CT slice-plan can be used to optimise dose distribution. (author)

  11. Numerical simulation of gas metal arc welding parametrical study

    International Nuclear Information System (INIS)

    Szanto, M.; Gilad, I.; Shai, I.; Quinn, T.P.

    2002-01-01

    The Gas Metal Arc Welding (GMAW) is a widely used welding process in the industry. The process variables are usually determined through extensive experiments. Numerical simulation, reduce the cost and extends the understanding of the process. In the present work, a versatile model for numerical simulation of GMAW is presented. The model provides the basis for fundamental understanding of the process. The model solves the magneto-hydrodynamic equations for the flow and temperature fields of the molten electrode and the plasma simultaneously, to form a fully coupled model. A commercial CFD code was extended to include the effects of radiation, Lorentz forces, Joule heating and thermoelectric effects. The geometry of the numerical model assembled to fit an experimental apparatus. To demonstrate the method, an aluminum electrode was modeled in a pure argon arc. Material properties and welding parameters are the input variables in the numerical model. In a typical process, the temperature distribution of the plasma is over 15000 K, resulting high non-linearity of the material properties. Moreover, there is high uncertainty in the available property data, at that range of temperatures. Therefore, correction factors were derived for the material properties to adjust between the numerical and the experimental results. Using the compensated properties, parametric study was performed. The effects of the welding parameters on the process, such the working voltage, electrode feed rate and shielding gas flow, were derived. The principal result of the present work is the ability to predict, by numerical simulation, the mode, size and frequency of the metal transferred from the electrode, which is the main material and energy source for the welding pool in GMAW

  12. Focus on Games & Simulations: Trends+Technologies+Case Studies

    Science.gov (United States)

    Weinstein, Margery

    2011-01-01

    A changing mindset combined with changing technology is driving the use of games and simulations. People are becoming more open to using games and simulations for learning, and, at the same time, the technologies are making the development of games and simulations easier and faster than a mere five years ago. Together, the changing mindset and the…

  13. Optorsim: A Grid Simulator for Studying Dynamic Data Replication Strategies

    CERN Document Server

    Bell, William H; Millar, A Paul; Capozza, Luigi; Stockinger, Kurt; Zini, Floriano

    2003-01-01

    Computational grids process large, computationally intensive problems on small data sets. In contrast, data grids process large computational problems that in turn require evaluating, mining and producing large amounts of data. Replication, creating geographically disparate identical copies of data, is regarded as one of the major optimization techniques for reducing data access costs. In this paper, several replication algorithms are discussed. These algorithms were studied using the Grid simulator: OptorSim. OptorSim provides a modular framework within which optimization strategies can be studied under different Grid configurations. The goal is to explore the stability and transient behaviour of selected optimization techniques. We detail the design and implementation of OptorSim and analyze various replication algorithms based on different Grid workloads.

  14. System studies for micro grid design: modeling and simulation examples

    Energy Technology Data Exchange (ETDEWEB)

    Rosa, Arlei Lucas S. [Federal University of Juiz de Fora (UFJF), MG (Brazil); Ribeiro, Paulo F. [Calvin College, Grand Rapids, MI (United States). Electrical Engineering Dept.

    2009-07-01

    The search for new energy sources to replace or increase the existing power plant of the traditional system leads to changes in concepts of energy generation and consumption. In this context, the concept of Microgrid has been developed and opens the opportunity for local power generation. The Microgrid can operate connected to the existing distribution network, increasing the reliability and safety of the system. Control measures and electronics interface are taken to maintain the network as a single and strong unit to any perturbation. This paper presents the typical system studies required to investigate the performance of a Microgrid operating under different system condition (e.g. interconnected or isolated from the utility grid and under system disturbance). Load flow and electromagnetic transient studies are used for modeling and simulation of a typical Microgrid configuration. (author)

  15. Improving Aviation Safety with information Visualization: A Flight Simulation Study

    Science.gov (United States)

    Aragon, Cecilia R.; Hearst, Marti

    2005-01-01

    Many aircraft accidents each year are caused by encounters with invisible airflow hazards. Recent advances in aviation sensor technology offer the potential for aircraft-based sensors that can gather large amounts of airflow velocity data in real-time. With this influx of data comes the need to study how best to present it to the pilot - a cognitively overloaded user focused on a primary task other than that of information visualization. In this paper, we present the results of a usability study of an airflow hazard visualization system that significantly reduced the crash rate among experienced helicopter pilots flying a high fidelity, aerodynamically realistic fixed-base rotorcraft flight simulator into hazardous conditions. We focus on one particular aviation application, but the results may be relevant to user interfaces in other operationally stressful environments.

  16. Ethylene glycol intercalation in smectites. molecular dynamics simulation studies

    International Nuclear Information System (INIS)

    Szczerba, Marek; Klapyta, Zenon; Kalinichev, Andrey

    2012-01-01

    Document available in extended abstract form only. Intercalation of ethylene glycol in smectites (glycolation) is widely used to discriminate smectites and vermiculites from other clays and among themselves. During this process, ethylene glycol molecules enter into the interlayer spaces of the swelling clays, leading to the formation of two-layer structure (∼17 A) in the case of smectites, or one-layer structure (∼14 A) in the case of vermiculites. In spite of the relatively broad literature on the understanding/characterization of ethylene glycol/water-clays complexes, the simplified structure of this complex presented by Reynolds (1965) is still used in the contemporary X-ray diffraction computer programs, which simulate structures of smectite and illite-smectite. The monolayer structure is only approximated using the assumption of the interlayer cation and ethylene glycol molecules lying in the middle of interlayer spaces. This study was therefore undertaken to investigate the structure of ethylene glycol/water-clays complex in more detail using molecular dynamics simulation. The structural models of smectites were built on the basis of pyrophyllite crystal structure (Lee and Guggenheim, 1981), with substitution of particular atoms. In most of simulations, the structural model assumed the following composition, considered as the most common in the mixed layer illite-smectites: EXCH 0.4 (Si 3.96 Al 0.04 )(Al 1.46 Fe 0.17 Mg 0.37 )O 10 (OH) 2 Atoms of the smectites were described with CLAYFF force field (Cygan et al., 2004), while atoms of water and ethylene glycol with flexible SPC and OPLS force fields, respectively. Ewald summation was used to calculate long range Coulombic interactions and the cutoff was set at 8.5 A. Results of the simulations show that in the two-layer glycolate the content of water is relatively small: up to 0.8 H 2 O per half of the smectite unit cell. Clear thermodynamic preference of mono- or two-layer structure of the complex is

  17. A protocol for conducting rainfall simulation to study soil runoff.

    Science.gov (United States)

    Kibet, Leonard C; Saporito, Louis S; Allen, Arthur L; May, Eric B; Kleinman, Peter J A; Hashem, Fawzy M; Bryant, Ray B

    2014-04-03

    Rainfall is a driving force for the transport of environmental contaminants from agricultural soils to surficial water bodies via surface runoff. The objective of this study was to characterize the effects of antecedent soil moisture content on the fate and transport of surface applied commercial urea, a common form of nitrogen (N) fertilizer, following a rainfall event that occurs within 24 hr after fertilizer application. Although urea is assumed to be readily hydrolyzed to ammonium and therefore not often available for transport, recent studies suggest that urea can be transported from agricultural soils to coastal waters where it is implicated in harmful algal blooms. A rainfall simulator was used to apply a consistent rate of uniform rainfall across packed soil boxes that had been prewetted to different soil moisture contents. By controlling rainfall and soil physical characteristics, the effects of antecedent soil moisture on urea loss were isolated. Wetter soils exhibited shorter time from rainfall initiation to runoff initiation, greater total volume of runoff, higher urea concentrations in runoff, and greater mass loadings of urea in runoff. These results also demonstrate the importance of controlling for antecedent soil moisture content in studies designed to isolate other variables, such as soil physical or chemical characteristics, slope, soil cover, management, or rainfall characteristics. Because rainfall simulators are designed to deliver raindrops of similar size and velocity as natural rainfall, studies conducted under a standardized protocol can yield valuable data that, in turn, can be used to develop models for predicting the fate and transport of pollutants in runoff.

  18. Superheating of Ag nanowires studied by molecular dynamics simulations

    International Nuclear Information System (INIS)

    Duan Wenshi; Ling Guangkong; Hong Lin; Li Hong; Liang Minghe

    2008-01-01

    The melting process of Ag nanowires was studied by molecular dynamics (MD) simulations at the atomic level. It is indicated that the Ag nanowires with Ni coating can be superheated depending on their radius and size. Also, in this paper the mechanism of superheating was analyzed and ascribed to the epitaxial Ag/Ni interface suppressing the nucleation and growth of melt. For the analysis, a thermodynamic model was constructed to describe the superheating mechanism of the Ni-coated Ag nanowires by considering the Ag/Ni interface free energy. We showed that the nucleation and growth of the Ag melt phase are both suppressed by the low energy Ag/Ni interfaces in Ni-coated Ag wires and the suppression of melt growth is crucial and plays a major role in the process of melting. The thermodynamic analysis gave a quantitative relation of superheating with the Ag wire radius and the contact angle of melting. The superheating decreased with Ag wire radius and also depended on the Ag/Ni interfacial condition. The results of the thermodynamic model were consistent with those of the MD simulations

  19. Simulation study on the growth of grains in dusty plasmas

    International Nuclear Information System (INIS)

    Sato, Tetsuya; Watanabe, Kunihiko

    1997-01-01

    A new particle simulation code is developed for studying the dynamics of the grains which are exposed to charging by the background plasma particles. Effects of regular attachment of electrons and ions, effects of secondary electron emission, and coagulation of grains are included in this code. Simulation results show that grains randomly change their charges from negative to positive, or from positive to negative in a 'flip-flop' fashion as a result of competition between the electron attachment and secondary electron emission. It is found that the flip-flop effect becomes remarkable when the radius of grains is of the order of 10 nm, because the attachment of a single electron to a grain is less effective on the surface potential for larger grains, while the average probability of electron attachment is smaller for smaller grains. Grains with opposite charges attract each other to coagulate, so that grains of size of 10 nm are likely to grow in size. The flip-flop effect is found to be essential to the growth of grains. (author)

  20. Simulation studies for the ATLAS upgrade Strip tracker

    CERN Document Server

    Wang, Jike; The ATLAS collaboration

    2017-01-01

    ATLAS is making extensive efforts towards preparing a detector upgrade for the High luminosity operations of the LHC (HL-LHC), which will commence operation in ~10 years. The current ATLAS Inner Detector will be replaced by a all-silicon tracker (comprising an inner Pixel tracker and outer Strip tracker). The software currently used for the new silicon tracker is broadly inherited from that used for the LHC Run 1 and 2, but many new developments have been made to better fulfil the future detector and operation requirements. One aspect in particular which will be highlighted is the simulation software for the Strip tracker. The available geometry description software (including the detailed description for all the sensitive elements, the services, etc.) did not allow for accurate modeling of the planned detector design. A range of sensors/layouts for the Strip tracker are being considered and must be studied in detailed simulations in order to assess the performance and ascertain that requirements are met. For...

  1. Simulation study of dielectrophoretic assembly of nanowire between electrode pairs

    Energy Technology Data Exchange (ETDEWEB)

    Tao, Quan, E-mail: taq3@pitt.edu; Lan, Fei; Jiang, Minlin [University of Pittsburgh, The Department of Electrical and Computer Engineering (United States); Wei, Fanan [Chinese Academy of Sciences, State Key Laboratory of Robotics, Shenyang Institute of Automation (China); Li, Guangyong, E-mail: gul6@pitt.edu [University of Pittsburgh, The Department of Electrical and Computer Engineering (United States)

    2015-07-15

    Dielectrophoresis (DEP) of rod-shaped nanostructures is attractive because of its exceptional capability to fabricate nanowire-based electronic devices. This efficient manipulation method, however, has a common side effect of assembling a certain number of nanowires at undesired positions. It is therefore essential to understand the underlying physics of DEP of nanowires in order to better guide the assembly. In this work, we propose theoretical methods to characterize the dielectrophoretic force and torque as well as the hydrodynamic drag force and torque on the nanowire (typical length: 10 μm). The trajectory of the nanowire is then simulated based on rigid body dynamics. The nanowire is predicted to either bridge the electrodes or attach on the surface of one electrode. A neighborhood in which the nanowire is more likely to bridge electrodes is found, which is conducive to successful assembly. The simulation study in this work provides us not only a better understanding of the underlying physics but also practical guidance on nanowire assembly by DEP.

  2. Laboratory simulation studies of uranium mobility in natural waters

    International Nuclear Information System (INIS)

    Giblin, A.M.; Swaine, D.J.; Batts, B.D.

    1981-01-01

    The effects of imposed variations of pH and Eh on aqueous uranium mobility at 25 0 C have been studied in three simulations of natural water systems. Constituents tested for their effect on uranium mobility were: (a) hydrous ferric oxide, to represent adsorptive solids which precipitate or dissolve in response to variations in pH and Eh; (b) kaolinite, representing minerals which, although modified by pH and Eh changes, are present as solids over the pH-Eh range of natural waters; and (c) carbonate, to represent a strong uranium-complexing species. Uranium mobility measurements from each simulation were regressed against pH and Eh within a range appropriate to natural waters. Hydrous ferric oxide and kaolinite each affected uranium mobility, but in separate pH-Eh domains. Aqueous carbonate increased mobility of uranium, and adsorption of UO 2 (CO 3 ) 3 4- caused colloidal dispersion of hydrous ferric oxide, possibly explaining the presence of 'hydrothermal hematite' in some uranium deposits. Enhanced uranium mobility observed in the pH-Eh domains of thermodynamically insoluble uranium oxides could be explained if the oxides were present as colloids. Uranium persisting as a mobile species, even after reduction, has implications for the near surface genesis of uranium ores. (author)

  3. Numerical simulation system for environmental studies: SPEEDI-MP

    International Nuclear Information System (INIS)

    Nagai, Haruyasu; Chino, Masamichi; Terada, Hiroaki; Harayama, Takaya; Kobayashi, Takuya; Tsuduki, Katsunori; Kim, Keyong-Ok; Furuno, Akiko

    2006-09-01

    A numerical simulation system SPEEDI-MP has been developed to apply for various environmental studies. SPEEDI-MP consists of dynamical models and material transport models for the atmospheric, terrestrial, and oceanic environments, meteorological and geographical database for model inputs, and system utilities for file management, visualization, analysis, etc., using graphical user interfaces (GUIs). As a numerical simulation tool, a model coupling program (model coupler) has been developed. It controls parallel calculations of several models and data exchanges among them to realize the dynamical coupling of the models. A coupled model system for water circulation has been constructed with atmosphere, ocean, wave, hydrology, and land-surface models using the model coupler. System utility GUIs are based on the Web technology, allowing users to manipulate all the functions on the system using their own PCs via the internet. In this system, the source estimation function in the atmospheric transport model can be executed on the grid computer system. Performance tests of the coupled model system for water circulation were also carried out for the flood event at Saudi Arabia in January 2005 and the storm surge case by the hurricane KATRINA in August 2005. (author)

  4. Study of silicon microstrips detector quantum efficiency using mathematical simulation

    International Nuclear Information System (INIS)

    Leyva Pernia, Diana; Cabal Rodriguez, Ana Ester; Pinnera Hernandez, Ibrahin; Fabelo, Antonio Leyva; Abreu Alfonso, Yamiel; Cruz Inclan, Carlos M.

    2011-01-01

    The paper shows the results from the application of mathematical simulation to study the quantum efficiency of a microstrips crystalline silicon detector, intended for medical imaging and the development of other applications such as authentication and dating of cultural heritage. The effects on the quantum efficiency of some parameters of the system, such as the detector-source geometry, X rays energy and detector dead zone thickness, were evaluated. The simulation results were compared with the theoretical prediction and experimental available data, resulting in a proper correspondence. It was concluded that the use of frontal configuration for incident energies lower than 17 keV is more efficient, however the use of the edge-on configuration for applications requiring the detection of energy above this value is recommended. It was also found that the reduction of the detector dead zone led to a considerable increase in quantum efficiency for any energy value in the interval from 5 to 100 keV.(author)

  5. Study and simulation of human interface; Human interface kenkyu to simulation

    Energy Technology Data Exchange (ETDEWEB)

    Nishitani, H. [Nara Institute of Science and Technology, Nara (Japan)

    1996-10-05

    Validation researches have begun about the interrelationship between systems and human beings using a virtual-reality plant environment. This article introduces some recent studies about the human interface in an operation control system in a virtual-reality environment. The evaluation of a system from the viewpoint of ease of use is called a usability test, to which a psychological protocol analysis is applied for finding out problematic points by carefully observing the operator actually operating the system. For instance, in a boiler plant simulator constructed for DCS training, the operator is given some tasks, such as the prediction as to how a certain event will develop, probing of the cause of anomalies, and execution of related operations. Video cameras are installed at various spots for the minute observation of facial expressions and behavior of the operator, and the operator`s recognition, thought, behavior, and utterances, expressed by the operator facially or verbally, are recorded and analyzed, and the results are utilized for system improvement and operator training. 3 refs., 2 figs.

  6. Integration of a driving simulator and a traffic simulator case study: Exploring drivers' behavior in response to variable message signs

    Directory of Open Access Journals (Sweden)

    Mansoureh Jeihani

    2017-12-01

    Full Text Available For the first time, a driving simulator has been integrated with a traffic simulator at the network level to allow subjects to drive in a fairly realistic environment with a realistic traffic flow and density. A 10 mi2 (25 km2 network was developed in a driving simulator and then exported to a traffic simulator. About 30 subjects drove the simulator under different traffic and driving conditions and variable message sign (VMS information, both with and without integration. Route guidance was available for the subjects. The challenges of the integration process are explained and its advantages investigated. The study concluded that traffic density, VMS reliability and compliance behavior are higher when driving and traffic simulators are integrated. To find factors affecting route diversion, researchers applied a binary logistic regression model. The results indicated that the original chosen route, displayed VMS information, subjects' attitude toward VMS information helpfulness, and their level of exposure to VMS affect route diversion. In addition, a multinomial logistic regression model was employed to investigate important factors in route choice. The results revealed that there is a significant correlation with driver route choice behavior and their actual travel time, the need for GPS, VMS exposure and also the designed scenarios. It should be noted that the paper was peer-reviewed by TRB and presented at the TRB Annual Meeting, Washington, D.C., January 2016. Keywords: Integration, Variable message sign, Compliance behavior, Driving simulator, Traffic simulator, Discrete choice analysis

  7. Simulation of a spintronic transistor: A study of its performance

    International Nuclear Information System (INIS)

    Pela, R.R.; Teles, L.K.

    2009-01-01

    We study theoretically the magnetic bipolar transistor, and compare its performance with common bipolar transistor. We present not only the simulation results for the characteristic curves, but also other relevant parameters related with its performance, such as: the current amplification factor, the open-loop gain, the hybrid parameters and the cutoff frequency. We noted that the spin-charge coupling introduces new phenomena that enrich the functionality characteristics of the magnetic bipolar transistor. Among other things, it has an adjustable band structure, which may be modified during the device operation; it exhibits the already known spin-voltaic effect. On the other hand, we observed that it is necessary a large g-factor to analyze the influence of the field B over the transistor. Nevertheless, we consider the magnetic bipolar transistor as a promising device for spintronic applications

  8. Bias-correction in vector autoregressive models: A simulation study

    DEFF Research Database (Denmark)

    Engsted, Tom; Pedersen, Thomas Quistgaard

    We analyze and compare the properties of various methods for bias-correcting parameter estimates in vector autoregressions. First, we show that two analytical bias formulas from the existing literature are in fact identical. Next, based on a detailed simulation study, we show that this simple...... and easy-to-use analytical bias formula compares very favorably to the more standard but also more computer intensive bootstrap bias-correction method, both in terms of bias and mean squared error. Both methods yield a notable improvement over both OLS and a recently proposed WLS estimator. We also...... of pushing an otherwise stationary model into the non-stationary region of the parameter space during the process of correcting for bias....

  9. Simulation study on ion extraction from ECR ion sources

    International Nuclear Information System (INIS)

    Fu, S.; Kitagawa, A.; Yamada, S.

    1993-07-01

    In order to study beam optics of NIRS-ECR ion source used in HIMAC, EGUN code has been modified to make it capable of modeling ion extraction from a plasma. Two versions of the modified code are worked out with two different methods in which 1-D and 2-D sheath theories are used respectively. Convergence problem of the strong nonlinear self-consistent equations is investigated. Simulations on NIRS-ECR ion source and HYPER-ECR ion source (in INS, Univ. of Tokyo) are presented in this paper, exhibiting an agreement with the experimental results. Some preliminary suggestions on the upgrading the extraction systems of these sources are also proposed. (author)

  10. Simulation study on ion extraction from ECR ion sources

    Energy Technology Data Exchange (ETDEWEB)

    Fu, S.; Kitagawa, A.; Yamada, S.

    1993-07-01

    In order to study beam optics of NIRS-ECR ion source used in HIMAC, EGUN code has been modified to make it capable of modeling ion extraction from a plasma. Two versions of the modified code are worked out with two different methods in which 1-D and 2-D sheath theories are used respectively. Convergence problem of the strong nonlinear self-consistent equations is investigated. Simulations on NIRS-ECR ion source and HYPER-ECR ion source (in INS, Univ. of Tokyo) are presented in this paper, exhibiting an agreement with the experimental results. Some preliminary suggestions on the upgrading the extraction systems of these sources are also proposed. (author).

  11. Anthem simulation studies of the plasma opening switch

    International Nuclear Information System (INIS)

    Mason, R.J.

    1993-01-01

    For a deeper understanding of the physical processes governing the Plasma Opening Switch (POS) the authors use the ANTHEM 2D implicit simulation code to study: (1) ion dynamical effects on electrohydrodynamic (EHD) waves propagating along steep density interfaces in the switch plasmas. At radial interfaces where the density jumps toward the anode, these waves can drive a finger of magnetic field into the plasma toward the load. Ion dynamics can open the rear of such fingers into a wedge-like density gap. Then: (2) they examine ion effects in uniform switch plasmas. These first develop potential hill structures at the drive edge of the cathode from the competition between electron velocity advection and EHD magnetic exclusion waves. Magnetic pressure gradients at the hill periphery and EHD effects then establish a density gap propagating along the cathode with radial electron emission from its tip. Similar results are obtained under both multi-fluid and PIC modeling on the plasma components

  12. A model ecosystem experiment and its computational simulation studies

    International Nuclear Information System (INIS)

    Doi, M.

    2002-01-01

    Simplified microbial model ecosystem and its computer simulation model are introduced as eco-toxicity test for the assessment of environmental responses from the effects of environmental impacts. To take the effects on the interactions between species and environment into account, one option is to select the keystone species on the basis of ecological knowledge, and to put it in the single-species toxicity test. Another option proposed is to put the eco-toxicity tests as experimental micro ecosystem study and a theoretical model ecosystem analysis. With these tests, the stressors which are more harmful to the ecosystems should be replace with less harmful ones on the basis of unified measures. Management of radioactive materials, chemicals, hyper-eutrophic, and other artificial disturbances of ecosystem should be discussed consistently from the unified view point of environmental protection. (N.C.)

  13. Cognitive distance, absorptive capacity and group rationality: a simulation study.

    Directory of Open Access Journals (Sweden)

    Petru Lucian Curşeu

    Full Text Available We report the results of a simulation study in which we explore the joint effect of group absorptive capacity (as the average individual rationality of the group members and cognitive distance (as the distance between the most rational group member and the rest of the group on the emergence of collective rationality in groups. We start from empirical results reported in the literature on group rationality as collective group level competence and use data on real-life groups of four and five to validate a mathematical model. We then use this mathematical model to predict group level scores from a variety of possible group configurations (varying both in cognitive distance and average individual rationality. Our results show that both group competence and cognitive distance are necessary conditions for emergent group rationality. Group configurations, in which the groups become more rational than the most rational group member, are groups scoring low on cognitive distance and scoring high on absorptive capacity.

  14. Cognitive distance, absorptive capacity and group rationality: a simulation study.

    Science.gov (United States)

    Curşeu, Petru Lucian; Krehel, Oleh; Evers, Joep H M; Muntean, Adrian

    2014-01-01

    We report the results of a simulation study in which we explore the joint effect of group absorptive capacity (as the average individual rationality of the group members) and cognitive distance (as the distance between the most rational group member and the rest of the group) on the emergence of collective rationality in groups. We start from empirical results reported in the literature on group rationality as collective group level competence and use data on real-life groups of four and five to validate a mathematical model. We then use this mathematical model to predict group level scores from a variety of possible group configurations (varying both in cognitive distance and average individual rationality). Our results show that both group competence and cognitive distance are necessary conditions for emergent group rationality. Group configurations, in which the groups become more rational than the most rational group member, are groups scoring low on cognitive distance and scoring high on absorptive capacity.

  15. Apertureless SNOM study on gold nanoparticles: Experiments and simulations

    Energy Technology Data Exchange (ETDEWEB)

    Chen, Weizhe; Kimel, Alexey; Kirilyuk, Andrei; Rasing, Theo [Institute for Molecules and Materials, Radboud University Nijmegen, Heyendaalseweg 135, 6525 AJ Nijmegen (Netherlands)

    2010-08-15

    Gold nanoparticles (about 10 nm in diameter) are investigated by an apertureless (or scattering-type) scanning near-field optical microscope (aSNOM) at 633 nm and a negative optical amplitude signal contrast is observed. To understand the size effect and the interactions between light, tip, and sample, an analytical solution is obtained by adopting a model considering the tip as a point dipole. This model successfully shows the contrast reversal measured in experiments. Some important aspects, however, are neglected by the quasistatic dipole model. Thus, three-dimensional (3D) numerical calculations by a finite integration technique are applied to study the interactions between tip apex, gold nanoparticle, and the substrate surface. The simulated near-field and far-field results help us not only to understand the experimentally acquired aSNOM images but also to investigate the complicated tip-particle-surface interactions. (Abstract Copyright [2010], Wiley Periodicals, Inc.)

  16. Bias-Correction in Vector Autoregressive Models: A Simulation Study

    Directory of Open Access Journals (Sweden)

    Tom Engsted

    2014-03-01

    Full Text Available We analyze the properties of various methods for bias-correcting parameter estimates in both stationary and non-stationary vector autoregressive models. First, we show that two analytical bias formulas from the existing literature are in fact identical. Next, based on a detailed simulation study, we show that when the model is stationary this simple bias formula compares very favorably to bootstrap bias-correction, both in terms of bias and mean squared error. In non-stationary models, the analytical bias formula performs noticeably worse than bootstrapping. Both methods yield a notable improvement over ordinary least squares. We pay special attention to the risk of pushing an otherwise stationary model into the non-stationary region of the parameter space when correcting for bias. Finally, we consider a recently proposed reduced-bias weighted least squares estimator, and we find that it compares very favorably in non-stationary models.

  17. Study of Flapping Flight Using Discrete Vortex Method Based Simulations

    Science.gov (United States)

    Devranjan, S.; Jalikop, Shreyas V.; Sreenivas, K. R.

    2013-12-01

    In recent times, research in the area of flapping flight has attracted renewed interest with an endeavor to use this mechanism in Micro Air vehicles (MAVs). For a sustained and high-endurance flight, having larger payload carrying capacity we need to identify a simple and efficient flapping-kinematics. In this paper, we have used flow visualizations and Discrete Vortex Method (DVM) based simulations for the study of flapping flight. Our results highlight that simple flapping kinematics with down-stroke period (tD) shorter than the upstroke period (tU) would produce a sustained lift. We have identified optimal asymmetry ratio (Ar = tD/tU), for which flapping-wings will produce maximum lift and find that introducing optimal wing flexibility will further enhances the lift.

  18. Degeneracy and long-range correlation: A simulation study

    Directory of Open Access Journals (Sweden)

    Marmelat Vivien

    2011-12-01

    Full Text Available We present in this paper a simulation study that aimed at evidencing a causal relationship between degeneracy and long-range correlations. Long-range correlations represent a very specific form of fluctuations that have been evidenced in the outcomes time series produced by a number of natural systems. Long-range correlations are supposed to sign the complexity, adaptability and flexibility of the system. Degeneracy is defined as the ability of elements that are structurally different to perform the same function, and is presented as a key feature for explaining the robustness of complex systems. We propose a model able to generate long-range correlated series, and including a parameter that account for degeneracy. Results show that a decrease in degeneracy tends to reduce the strength of long-range correlation in the series produced by the model.

  19. Monte Carlo simulations and benchmark studies at CERN's accelerator chain

    CERN Document Server

    AUTHOR|(CDS)2083190; Brugger, Markus

    2016-01-01

    Mixed particle and energy radiation fields present at the Large Hadron Collider (LHC) and its accelerator chain are responsible for failures on electronic devices located in the vicinity of the accelerator beam lines. These radiation effects on electronics and, more generally, the overall radiation damage issues have a direct impact on component and system lifetimes, as well as on maintenance requirements and radiation exposure to personnel who have to intervene and fix existing faults. The radiation environments and respective radiation damage issues along the CERN’s accelerator chain were studied in the framework of the CERN Radiation to Electronics (R2E) project and are hereby presented. The important interplay between Monte Carlo simulations and radiation monitoring is also highlighted.

  20. White book Escrime. Climatic simulation studies; Livre blanc Escrime. Etude des simulations climatiques

    Energy Technology Data Exchange (ETDEWEB)

    Terray, L [CERFACS, 31 - Toulouse (France); Braconnot, P [Institut Pierre-Simon Laplace IPSL/LSCE, CEA-Orme des Merisiers, 91 - Gif-sur-Yvette (France)

    2007-01-15

    The ESCRIME project aims to manage the analysis realized on the climatic simulations on the framework of the fourth report of the GIEC (group of intergovernmental experts on the climate evolution), in particularly the simulations based on french models. This white book is constituted by 8 chapters: the global scenario, the climatic sensibility, the variation modes, the regionalization and the extremes, the hydrological cycle, the polar regions and the cryo-sphere, the carbon cycle, detection and attributions. (A.L.B.)

  1. Nuclear power plant diagnostics study at the Midland Training Simulator

    International Nuclear Information System (INIS)

    Reifman, J.; Rank, P.; Lee, J.C.; Wehe, D.K.

    1991-01-01

    This paper discusses the implementation of two advanced diagnostic concepts for nuclear power plant diagnostics, the systematic generation and updating of a rule-based system and the simulation filter, at the Midland Nuclear Power Plant Unit 2 Training Simulator. The authors use an entropy minimax pattern recognition algorithm for the systematic construction of the diagnostic rule base. By extracting information from a transient database constructed with the Midland Simulator, the algorithm searches for trends in plant parameters, forming patterns or rules that describe the behavior of the transients. The rules are updated in an incremental manner within the context of the entropy minimax algorithm. The simulation filter is a nonlinear parameter estimation algorithm based on the extended Kalman filter. The authors use the simulation filter to improve the results of crude simulation models by optimally estimating system states given a set of measurements and results from a nonlinear simulation program. The Midland Simulator results of the Three Mile Island accident are significantly improved with the use of the simulation filter

  2. A study on the shielding element using Monte Carlo simulation

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Ki Jeong [Dept. of Radiology, Konkuk University Medical Center, Seoul (Korea, Republic of); Shim, Jae Goo [Dept. of Radiologic Technology, Daegu Health College, Daegu (Korea, Republic of)

    2017-06-15

    In this research, we simulated the elementary star shielding ability using Monte Carlo simulation to apply medical radiation shielding sheet which can replace existing lead. In the selection of elements, mainly elements and metal elements having a large atomic number, which are known to have high shielding performance, recently, various composite materials have improved shielding performance, so that weight reduction, processability, In consideration of activity etc., 21 elements were selected. The simulation tools were utilized Monte Carlo method. As a result of simulating the shielding performance by each element, it was estimated that the shielding ratio is the highest at 98.82% and 98.44% for tungsten and gold.

  3. Thermal expansion study of simulated DUPIC fuel using neutron diffraction

    International Nuclear Information System (INIS)

    Kang, Kweon Ho; Ryu, H. J.; Bae, J. H.; Kim, H. S.; Song, K. C.; Yang, M. S.; Choi, Y. N.; Han, Y. S.; Oh, H. S.

    2001-07-01

    The lattice parameters of simulated DUPIC fuel and UO2 were measured from room temperature to 1273 K using neutron diffraction to investigate the thermal expansion and density variation with temperature. The lattice parameter of simulated DUPIC fuel is lower than that of UO2 and the linear thermal expansion of simulated DUPIC fuel is higher than that of UO2. For the temperature range from 298 to 1273 K, the average linear thermal expansion coefficients for UO2 and simulated DUPIC fuel are 10.471 ''10-6 and 10.751 ''10-6 K-1, respectively

  4. Dependence of Substorm Evolution on Solar Wind Condition: Simulation Study

    Science.gov (United States)

    Kamiyoshikawa, N.; Ebihara, Y.; Tanaka, T.

    2017-12-01

    A substorm is one of the remarkable disturbances occurring in the magnetosphere. It is known that the substorm occurs frequently when IMF is southward and solar wind speed is high. However, the physical process to determine substorm scale is not well understood. We reproduced substorms by using global MHD simulation, calculated auroral electrojet (ionospheric Hall current) flowing in the ionosphere to investigate the dependence of substorm evolution on solar wind condition. Solar wind speed of 372.4 km/s and IMF Bz of 5.0 nT were imposed to, obtain the quasi-stationary state of the magnetosphere. Then the solar wind parameters were changed as a step function. For the solar wind speed, we assumed 300 km/s, 500 km/s and 700 km/s. For IMF, we assumed -1.0 nT, -3.0 nT, -5.0 nT, -7.0 nT and -9.0 nT. In total, 15 simulation runs were performed. In order to objectively evaluate the substorm, the onset was identified with the method based on the one proposed by Newell et al. (2011). This method uses the SME index that is an extension of the AE index. In this study, the geomagnetic variation induced by the ionospheric Hall current was obtained every 1 degree from the magnetic latitude 40 degrees to 80 degrees and in every 0.5 hours in the magnetic region direction. The upper and the lower envelopes of the geomagnetic variation are regarded as SMU index and SML index, respectively. The larger the solar wind speed, the larger the southward IMF, the more the onset tends to be faster. This tendency is consistent with the onset occurrence probability indicated by Newell et al. (2016). Moreover, the minimum value of the SML index within 30 minutes from the beginning of the onset tends to decrease with the solar wind speed and the magnitude of the southward IMF. A rapid decrease of the SML index can be explained by a rapid increase in the field-aligned currents flowing in and out of the nightside ionosphere. This means that electromagnetic energies flowing into the ionosphere

  5. A study of reset mode in advanced alarm system simulator

    International Nuclear Information System (INIS)

    Yenn, T. C.; Hwang, S. L.; Huang, F. H.; Yu, A. C.; Hsu, C. C.; Huang, H. W.

    2006-01-01

    An automation function has been widely applied in main control room of nuclear power plants. That leads to a new issue of human-automation interaction, which considers human operational performance in automated systems. In this research is the automation alarm reset in the advanced alarm system (AAS) of Advanced Nuclear Power Plant in Taiwan. Since alarms are very crucial for the understanding of the status of the plant as well as the reset function of alarm system will be changed from fully manual to fully automatic, it is very important to test and evaluate the performance and the effect of reset modes in AAS. The purpose of this paper is to evaluate the impact of the auto-reset alarm system on the plant performance and on operators' preference and task load. To develop a dynamic simulator as an AAS was conducted to compare manual and automatic reset function of alarm system on task performance and subjective ratings of task workload, comprehension, and preference. The simulation includes PCTRAN model and alarm software processing. The final results revealed that, using the auto-reset mode, participants had lower task load index (TLX) on effort in the first test trial and was more satisfied in multiple tasks condition. In contrast, using manual reset mode, participants were more satisfied on alarm handling, monitoring, and decision making. In other words, either reset mode in the study has unique features to assist operator, but is insufficient. The reset function in AAS therefore should be very flexible. Additionally, the experimental results also pointed out that the user interfaces need to be improved. Those experiences will be helpful for human factors verification and validation in the near future. (authors)

  6. Physics validation studies for muon collider detector background simulations

    International Nuclear Information System (INIS)

    Morris, Aaron Owen

    2011-01-01

    Within the broad discipline of physics, the study of the fundamental forces of nature and the most basic constituents of the universe belongs to the field of particle physics. While frequently referred to as 'high-energy physics,' or by the acronym 'HEP,' particle physics is not driven just by the quest for ever-greater energies in particle accelerators. Rather, particle physics is seen as having three distinct areas of focus: the cosmic, intensity, and energy frontiers. These three frontiers all provide different, but complementary, views of the basic building blocks of the universe. Currently, the energy frontier is the realm of hadron colliders like the Tevatron at Fermi National Accelerator Laboratory (Fermilab) or the Large Hadron Collider (LHC) at CERN. While the LHC is expected to be adequate for explorations up to 14 TeV for the next decade, the long development lead time for modern colliders necessitates research and development efforts in the present for the next generation of colliders. This paper focuses on one such next-generation machine: a muon collider. Specifically, this paper focuses on Monte Carlo simulations of beam-induced backgrounds vis-a-vis detector region contamination. Initial validation studies of a few muon collider physics background processes using G4beamline have been undertaken and results presented. While these investigations have revealed a number of hurdles to getting G4beamline up to the level of more established simulation suites, such as MARS, the close communication between us, as users, and the G4beamline developer, Tom Roberts, has allowed for rapid implementation of user-desired features. The main example of user-desired feature implementation, as it applies to this project, is Bethe-Heitler muon production. Regarding the neutron interaction issues, we continue to study the specifics of how GEANT4 implements nuclear interactions. The GEANT4 collaboration has been contacted regarding the minor discrepancies in the neutron

  7. A New Simulation Technique for Study of Collisionless Shocks: Self-Adaptive Simulations

    International Nuclear Information System (INIS)

    Karimabadi, H.; Omelchenko, Y.; Driscoll, J.; Krauss-Varban, D.; Fujimoto, R.; Perumalla, K.

    2005-01-01

    The traditional technique for simulating physical systems modeled by partial differential equations is by means of time-stepping methodology where the state of the system is updated at regular discrete time intervals. This method has inherent inefficiencies. In contrast to this methodology, we have developed a new asynchronous type of simulation based on a discrete-event-driven (as opposed to time-driven) approach, where the simulation state is updated on a 'need-to-be-done-only' basis. Here we report on this new technique, show an example of particle acceleration in a fast magnetosonic shockwave, and briefly discuss additional issues that we are addressing concerning algorithm development and parallel execution

  8. Salt Effect on Osmotic Pressure of Polyelectrolyte Solutions: Simulation Study

    Directory of Open Access Journals (Sweden)

    Jan-Michael Y. Carrillo

    2014-07-01

    Full Text Available Abstract: We present results of the hybrid Monte Carlo/molecular dynamics simulations of the osmotic pressure of salt solutions of polyelectrolytes. In our simulations, we used a coarse-grained representation of polyelectrolyte chains, counterions and salt ions. During simulation runs, we alternate Monte Carlo and molecular dynamics simulation steps. Monte Carlo steps were used to perform small ion exchange between simulation box containing salt ions (salt reservoir and simulation box with polyelectrolyte chains, counterions and salt ions (polyelectrolyte solution. This allowed us to model Donnan equilibrium and partitioning of salt and counterions across membrane impermeable to polyelectrolyte chains. Our simulations have shown that the main contribution to the system osmotic pressure is due to salt ions and osmotically active counterions. The fraction of the condensed (osmotically inactive counterions first increases with decreases in the solution ionic strength then it saturates. The reduced value of the system osmotic coefficient is a universal function of the ratio of the concentration of osmotically active counterions and salt concentration in salt reservoir. Simulation results are in a very good agreement with osmotic pressure measurements in sodium polystyrene sulfonate, DNA, polyacrylic acid, sodium polyanetholesulfonic acid, polyvinylbenzoic acid, and polydiallyldimethylammonium chloride solutions.

  9. Combining hardware and simulation for datacenter scaling studies

    DEFF Research Database (Denmark)

    Ruepp, Sarah Renée; Pilimon, Artur; Thrane, Jakob

    2017-01-01

    and simulation to illustrate the scalability and performance of datacenter networks. We simulate a Datacenter network and interconnect it with real world traffic generation hardware. Analysis of the introduced packet conversion and virtual queueing delays shows that the conversion efficiency is at the order...

  10. Large Eddy Simulation Study for Fluid Disintegration and Mixing

    Science.gov (United States)

    Bellan, Josette; Taskinoglu, Ezgi

    2011-01-01

    A new modeling approach is based on the concept of large eddy simulation (LES) within which the large scales are computed and the small scales are modeled. The new approach is expected to retain the fidelity of the physics while also being computationally efficient. Typically, only models for the small-scale fluxes of momentum, species, and enthalpy are used to reintroduce in the simulation the physics lost because the computation only resolves the large scales. These models are called subgrid (SGS) models because they operate at a scale smaller than the LES grid. In a previous study of thermodynamically supercritical fluid disintegration and mixing, additional small-scale terms, one in the momentum and one in the energy conservation equations, were identified as requiring modeling. These additional terms were due to the tight coupling between dynamics and real-gas thermodynamics. It was inferred that if these terms would not be modeled, the high density-gradient magnitude regions, experimentally identified as a characteristic feature of these flows, would not be accurately predicted without the additional term in the momentum equation; these high density-gradient magnitude regions were experimentally shown to redistribute turbulence in the flow. And it was also inferred that without the additional term in the energy equation, the heat flux magnitude could not be accurately predicted; the heat flux to the wall of combustion devices is a crucial quantity that determined necessary wall material properties. The present work involves situations where only the term in the momentum equation is important. Without this additional term in the momentum equation, neither the SGS-flux constant-coefficient Smagorinsky model nor the SGS-flux constant-coefficient Gradient model could reproduce in LES the pressure field or the high density-gradient magnitude regions; the SGS-flux constant- coefficient Scale-Similarity model was the most successful in this endeavor although not

  11. When does alcohol hurt? A driving simulator study.

    Science.gov (United States)

    Vollrath, Mark; Fischer, Josefine

    2017-12-01

    World-wide, alcohol is still a major cause of traffic accidents. The dose-related accident risk function has been found in a large number of risk studies. A plethora of laboratory studies has examined the effect of alcohol with regard to different information processing capabilities of drivers. Summarizing the results, alcohol effects occur at lower blood alcohol concentrations (BAC) the more complex the tasks get. However, in contrast, typical alcohol-related crashes are frequently single vehicle crashes but not so often crashes in complex situations like at intersections. It may be that the subjective assessment of the traffic situation and the adaptation of behavior under the influence of alcohol plays a major role in accident causation. In order to examine this hypothesis, two driving simulator studies were conducted at a target BAC of 0.5g/l comparing two (alcohol vs. placebo; n=48, Experiment 1) and three (sober, placebo and alcohol; n=63, Experiment 2) groups of subjects in two critical scenarios. The first scenario was a seemingly easy traffic situation and was supposed to lead to a relaxed driving behavior under alcohol. The second scenario involved a complex intersection situation where especially drivers under the influence of alcohol should try to concentrate and compensate their experienced alcohol effects. In all scenarios, a critical object appeared suddenly and the driver had to react fast in order to prevent a (simulated) accident. Overall, the results support the hypothesis. Accidents were more frequent for alcohol drivers as compared to placebo/sober drivers in the easy scenario, but not the complex one. The initial speed of the driver when entering the scenario seems to play a major role in the accident causation. Drivers under the influence of alcohol seem to lower their speed in complex scenarios, possibly to thus counteract alcohol effects. In seemingly easy scenarios this does not seem necessary for them and the arousing effect of alcohol

  12. Simulation studies on measures to mitigate ion clouds

    Energy Technology Data Exchange (ETDEWEB)

    Babu Ganta, Prasanth; Masood, Ahmed; Rienen, Ursula van [Universitaet Rostock, Institut fuer Allgemeine Elektrotechnik (Germany); Sauerland, Dennis; Hillert, Wolfgang [Physikalisches Institut der Universitaet Bonn, ELSA (Germany); Meseck, Atoosa [HZB, Institut Beschleunigerphysik, Berlin (Germany)

    2016-07-01

    For future Energy Recovery Linacs (ERL), parasitic ions, which are generated by collisions of the beam and the rest gas in the vacuum chamber, present a limiting factor for the high current-low emittance electron beams. Clearing gaps, clearing electrodes and appropriate filling patterns are a remedy to keep the ion density in the accelerator at a level that allows for a minimum stability of the beam parameters. The MOEVE PIC Tracking code, which employs a 2D wake matrix, enables tracking simulations of the ion distribution over a relatively long period of up to thousands of interactions with the passing bunches. It enables to develop a deeper understanding of the ion-cloud behavior in order to design appropriate measures for their mitigation. For certain cases, it is sufficient to study the problem in 2D. Therefore, an additional 2D solver shall be implemented into MOEVE PIC Tracking in order to reduce the computation times. Numerical studies of ion cloud dynamics in beam guiding magnets and drift sections of electron machines will be shown and compared with experimental results obtained at the ELSA facility.

  13. Physical layer simulation study for the coexistence of WLAN standards

    Energy Technology Data Exchange (ETDEWEB)

    Howlader, M. K. [Marquette Univ., 222 Haggerty Hall, P. O. Box 1881, Milwaukee, WI 53201 (United States); Keiger, C. [Analysis and Measurement Services Corporation, 9111 Cross Park Drive, Knoxville, TN 37923 (United States); Ewing, P. D. [Oak Ridge National Laboratory, MS-6006, P. O. Box 2008, Oak Ridge, TN 37831 (United States); Govan, T. V. [U.S. Nuclear Regulatory Commission, MS T-10-D20, 11545 Rockville Pike, Rockville, MD 20852 (United States)

    2006-07-01

    This paper presents the results of a study on the performance of wireless local area network (WLAN) devices in the presence of interference from other wireless devices. To understand the coexistence of these wireless protocols, simplified physical-layer-system models were developed for the Bluetooth, Wireless Fidelity (WiFi), and Zigbee devices, all of which operate within the 2.4-GHz frequency band. The performances of these protocols were evaluated using Monte-Carlo simulations under various interference and channel conditions. The channel models considered were basic additive white Gaussian noise (AWGN), Rayleigh fading, and site-specific fading. The study also incorporated the basic modulation schemes, multiple access techniques, and channel allocations of the three protocols. This research is helping the U.S. Nuclear Regulatory Commission (NRC) understand the coexistence issues associated with deploying wireless devices and could prove useful in the development of a technical basis for guidance to address safety-related issues with the implementation of wireless systems in nuclear facilities. (authors)

  14. Transethnic differences in GWAS signals: A simulation study.

    Science.gov (United States)

    Zanetti, Daniela; Weale, Michael E

    2018-05-07

    Genome-wide association studies (GWASs) have allowed researchers to identify thousands of single nucleotide polymorphisms (SNPs) and other variants associated with particular complex traits. Previous studies have reported differences in the strength and even the direction of GWAS signals across different populations. These differences could be due to a combination of (1) lack of power, (2) allele frequency differences, (3) linkage disequilibrium (LD) differences, and (4) true differences in causal variant effect sizes. To determine whether properties (1)-(3) on their own might be sufficient to explain the patterns previously noted in strong GWAS signals, we simulated case-control data of European, Asian and African ancestry, applying realistic allele frequencies and LD from 1000 Genomes data but enforcing equal causal effect sizes across populations. Much of the observed differences in strong GWAS signals could indeed be accounted for by allele frequency and LD differences, enhanced by the Euro-centric SNP bias and lower SNP coverage found in older GWAS panels. While we cannot rule out a role for true transethnic effect size differences, our results suggest that strong causal effects may be largely shared among human populations, motivating the use of transethnic data for fine-mapping. © 2018 John Wiley & Sons Ltd/University College London.

  15. Physical layer simulation study for the coexistence of WLAN standards

    International Nuclear Information System (INIS)

    Howlader, M. K.; Keiger, C.; Ewing, P. D.; Govan, T. V.

    2006-01-01

    This paper presents the results of a study on the performance of wireless local area network (WLAN) devices in the presence of interference from other wireless devices. To understand the coexistence of these wireless protocols, simplified physical-layer-system models were developed for the Bluetooth, Wireless Fidelity (WiFi), and Zigbee devices, all of which operate within the 2.4-GHz frequency band. The performances of these protocols were evaluated using Monte-Carlo simulations under various interference and channel conditions. The channel models considered were basic additive white Gaussian noise (AWGN), Rayleigh fading, and site-specific fading. The study also incorporated the basic modulation schemes, multiple access techniques, and channel allocations of the three protocols. This research is helping the U.S. Nuclear Regulatory Commission (NRC) understand the coexistence issues associated with deploying wireless devices and could prove useful in the development of a technical basis for guidance to address safety-related issues with the implementation of wireless systems in nuclear facilities. (authors)

  16. Evaluating best educational practices, student satisfaction, and self-confidence in simulation: A descriptive study.

    Science.gov (United States)

    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

  17. Comparative study of the effectiveness of three learning environments: Hyper-realistic virtual simulations, traditional schematic simulations and traditional laboratory

    Directory of Open Access Journals (Sweden)

    Maria Isabel Suero

    2011-10-01

    Full Text Available This study compared the educational effects of computer simulations developed in a hyper-realistic virtual environment with the educational effects of either traditional schematic simulations or a traditional optics laboratory. The virtual environment was constructed on the basis of Java applets complemented with a photorealistic visual output. This new virtual environment concept, which we call hyper-realistic, transcends basic schematic simulation; it provides the user with a more realistic perception of a physical phenomenon being simulated. We compared the learning achievements of three equivalent, homogeneous groups of undergraduates—an experimental group who used only the hyper-realistic virtual laboratory, a first control group who used a schematic simulation, and a second control group who used the traditional laboratory. The three groups received the same theoretical preparation and carried out equivalent practicals in their respective learning environments. The topic chosen for the experiment was optical aberrations. An analysis of variance applied to the data of the study demonstrated a statistically significant difference (p value <0.05 between the three groups. The learning achievements attained by the group using the hyper-realistic virtual environment were 6.1 percentage points higher than those for the group using the traditional schematic simulations and 9.5 percentage points higher than those for the group using the traditional laboratory.

  18. Validation and computing and performance studies for the ATLAS simulation

    CERN Document Server

    Marshall, Z; The ATLAS collaboration

    2009-01-01

    We present the validation of the ATLAS simulation software pro ject. Software development is controlled by nightly builds and several levels of automatic tests to ensure stability. Computing validation, including CPU time, memory, and disk space required per event, is benchmarked for all software releases. Several different physics processes and event types are checked to thoroughly test all aspects of the detector simulation. The robustness of the simulation software is demonstrated by the production of 500 million events on the World-wide LHC Computing Grid in the last year.

  19. Study of drift tube resolution using numerical simulations

    International Nuclear Information System (INIS)

    Lundin, M.C.

    1990-01-01

    The results off a simulation of straw tube detector response are presented. These gas ionization detectors and the electronics which must presumably go along with them are characterized in a simple but meaningful manner. The physical processes which comprise the response of the individual straw tubes are broken down and examined in detail. Different parameters of the simulation are varied and resulting predictions of drift tube spatial resolution are shown. In addition, small aspects of the predictions are compared to recent laboratory results, which can be seen as a measure of the simulation's usefulness. 10 refs., 8 figs

  20. Loading Deformation Characteristic Simulation Study of Engineering Vehicle Refurbished Tire

    Science.gov (United States)

    Qiang, Wang; Xiaojie, Qi; Zhao, Yang; Yunlong, Wang; Guotian, Wang; Degang, Lv

    2018-05-01

    The paper constructed engineering vehicle refurbished tire computer geometry model, mechanics model, contact model, finite element analysis model, did simulation study on load-deformation property of engineering vehicle refurbished tire by comparing with that of the new and the same type tire, got load-deformation of engineering vehicle refurbished tire under the working condition of static state and ground contact. The analysis result shows that change rules of radial-direction deformation and side-direction deformation of engineering vehicle refurbished tire are close to that of the new tire, radial-direction and side-direction deformation value is a little less than that of the new tire. When air inflation pressure was certain, radial-direction deformation linear rule of engineer vehicle refurbished tire would increase with load adding, however, side-direction deformation showed linear change rule, when air inflation pressure was low; and it would show increase of non-linear change rule, when air inflation pressure was very high.

  1. A comparative study of accelerated tests to simulate atmospheric corrosion

    International Nuclear Information System (INIS)

    Assis, Sergio Luiz de

    2000-01-01

    In this study, specimens coated with five organic coating systems were exposed to accelerated tests for periods up to 2000 hours, and also to weathering for two years and six months. The accelerated tests consisted of the salt spray test, according to ASTM B-117; Prohesion (ASTM G 85-98 annex 5A); Prohesion combined with cyclic exposure to UV-A radiation and condensation; 'Prohchuva' a test described by ASTM G 85-98 using a salt spray with composition that simulated the acid rain of Sao Paulo, but one thousand times more concentrated, and 'Prohchuva' combined with cyclic exposure to UV-A radiation and condensation. The coated specimens were exposed with and without incision to expose the substrate. The onset and progress of corrosion at and of the exposed metallic surface, besides coating degradation, were followed by visual observation, and photographs were taken. The coating systems were classified according to the extent of corrosion protection given to the substrate, using a method based on ASTM standards D-610, D-714, D-1654 and D-3359. The rankings of the coatings obtained from accelerated tests and weathering were compared and contrasted with classification of the same systems obtained from literature, for specimens exposed to an industrial atmosphere. Coating degradation was strongly dependent on the test, and could be attributed to differences in test conditions. The best correlation between accelerated test and weathering was found for the test Prohesion alternated with cycles of exposure to UV-A radiation and condensation. (author)

  2. Simulated study of solid materials used as phantoms

    International Nuclear Information System (INIS)

    Belmonte, Eduardo P.; Pinheiro, Christiano J.G.; Pinto, Nivia G.Villela; Braz, Delson; Pereira Junior, Sielso B.; Lima, Gilberto S.

    2005-01-01

    The aim of this study is to analyze the behavior of electrons in water and compares them with the behavior in the materials you want to analyze. It were simulated, using Monte Carlo code EGS4 (MC), 24 irradiation with electrons of 6 and 20 MeV in different materials (polyethylene C 2 H 4 ) n , polystyrene (C 8 H 8 ) n , lucite (C 5 H 8 O 2 ), nylon (C 6 H 11 NO), water (H 2 O) and solid water (55% polyethylene, polystyrene and 5% 40% calcium oxide). The data show that for the two energies most of radiation does not interact with the first 20 mm materials. However, when analyzed plates of 1 cm, most of the energy is deposited in the first 4 plates in case 6 MeV and in the first ten to 20 MeV electrons, for all materials. In case of similarity in behavior of radiation in water and other materials, it is observed that is in polyethylene and polystyrene that the behaviour of electrons more resembles the behavior in water

  3. Simulation study of dynamo structure in reversed field pinch

    International Nuclear Information System (INIS)

    Nagata, A.; Sato, K.I.; Ashida, H.; Amano, T.

    1992-10-01

    The dynamo structure in the reversed field pinch (RFP) is studied through the nonlinear dynamics of single-helicity mode. Simulation is concentrated upon the physical structure of nonlinear interactions of the plasma flow and magnetic fluctuation. The result indicates that when the initial equilibrium profile is deformed by resistive diffusion, the radial flow is driven near the core of the plasma. As this flow forms a vortex structure and magnetic fluctuation grows radially, the dynamo electric field is spirally induced just inside the reversal surface and then the toroidal flux is increased. This dynamo electric field correlates to nonlinear evolution of the kinetic energy of m=1 mode, and the increase of the toroidal flux is originated in the growth process of the magnetic energy of this mode. Consequently, the RFP configuration can be sustained by the single-helicity evolution of m=1 mode alone, and the electric field induced by the interactions of the toroidal velocity and the radial magnetic field is the most dominant source on the dynamo action. (author)

  4. Drying studies of simulated DOE aluminum plate fuels

    International Nuclear Information System (INIS)

    Lords, R.E.; Windes, W.E.; Crepeau, J.C.; Sidwell, R.W.

    1996-01-01

    Experiments have been conducted to validate the Idaho National Engineering Laboratory (INEL) drying procedures for preparation of corroded aluminum plate fuel for dry storage in an existing vented (and filtered) fuel storage facility. A mixture of hydrated aluminum oxide bound with a clay was used to model the aluminum corrosion product and sediment expected in these Department of Energy (DOE) owned fuel types. Previous studies demonstrated that the current drying procedures are adequate for removal of free water inside the storage canister and for transfer of this fuel to a vented dry storage facility. However, using these same drying procedures, the simulated corrosion product was found to be difficult to dry completely from between the aluminum clad plates of the fuel. Another related set of experiments was designed to ensure that the fuel would not be damaged during the drying process. Aluminum plate fuels are susceptible to pitting damage on the cladding that can result in a portion of UAl x fuel meat being disgorged. This would leave a water-filled void beneath the pit in the cladding. The question was whether bursting would occur when water in the void flashes to steam, causing separation of the cladding from the fuel, and/or possible rupture. Aluminum coupons were fabricated to model damaged fuel plates. These coupons do not rupture or sustain any visible damage during credible drying scenarios

  5. The neural basis of event simulation: an FMRI study.

    Directory of Open Access Journals (Sweden)

    Yukihito Yomogida

    Full Text Available Event simulation (ES is the situational inference process in which perceived event features such as objects, agents, and actions are associated in the brain to represent the whole situation. ES provides a common basis for various cognitive processes, such as perceptual prediction, situational understanding/prediction, and social cognition (such as mentalizing/trait inference. Here, functional magnetic resonance imaging was used to elucidate the neural substrates underlying important subdivisions within ES. First, the study investigated whether ES depends on different neural substrates when it is conducted explicitly and implicitly. Second, the existence of neural substrates specific to the future-prediction component of ES was assessed. Subjects were shown contextually related object pictures implying a situation and performed several picture-word-matching tasks. By varying task goals, subjects were made to infer the implied situation implicitly/explicitly or predict the future consequence of that situation. The results indicate that, whereas implicit ES activated the lateral prefrontal cortex and medial/lateral parietal cortex, explicit ES activated the medial prefrontal cortex, posterior cingulate cortex, and medial/lateral temporal cortex. Additionally, the left temporoparietal junction plays an important role in the future-prediction component of ES. These findings enrich our understanding of the neural substrates of the implicit/explicit/predictive aspects of ES-related cognitive processes.

  6. Epidemiological impact of a syphilis vaccine: a simulation study.

    Science.gov (United States)

    Champredon, D; Cameron, C E; Smieja, M; Dushoff, J

    2016-11-01

    Despite the availability of inexpensive antimicrobial treatment, syphilis remains prevalent worldwide, affecting millions of individuals. Furthermore, syphilis infection is suspected of increasing both susceptibility to, and tendency to transmit, HIV. Development of a syphilis vaccine would be a potentially promising step towards control, but the value of dedicating resources to vaccine development should be evaluated in the context of the anticipated benefits. Here, we use a detailed mathematical model to explore the potential impact of rolling out a hypothetical syphilis vaccine on morbidity from both syphilis and HIV and compare it to the impact of expanded 'screen and treat' programmes using existing treatments. Our results suggest that an efficacious vaccine has the potential to sharply reduce syphilis prevalence under a wide range of scenarios, while expanded treatment interventions are likely to be substantially less effective. Our modelled interventions in our simulated study populations are expected to have little effect on HIV, and in some scenarios lead to small increases in HIV incidence, suggesting that interventions against syphilis should be accompanied with interventions against other sexually transmitted infections to prevent the possibility that lower morbidity or lower perceived risk from syphilis could lead to increases in other sexually transmitted diseases.

  7. Study on pulsed current cathodic protection in a simulated system

    Energy Technology Data Exchange (ETDEWEB)

    Yan, Milin; Li, Helin [Xi' an Jiao Tong Universitiy (China)]|[Tubular Goods Research Center of China National Petroleum Corp. (China); Qiu, Yubing; Guo, Xingpeng [Hua Zhong University of Science and Techonology (China)

    2004-07-01

    The pulsed current cathodic protection (PCCP) is a new cathodic protection (CP) technology and shows more advantages over the conventional DC cathodic protection (DCCP) in oil well casing system. However, little information about PCCP is reported. In this research, a simulated CP system was set up in a pool of 3.5 m x 2.0 m x 3.0 m size, in which the effects of the square wave pulsed current (SWPC) parameters (amplitude: IA, frequency: f, duty cycle: P), auxiliary anode distance (d) and media conductivity ({mu}) on the cathodic potential (E) distribution were studied, and the protection effects of PCCP and DCCP were compared. The results show that with increase of the square wave parameters (IA, f, P), the E distribution becomes more negative and the effects of each current parameter are relate closely to the cathode polarizing state. Only with suitable square wave parameters can the whole cathode be effectively protected. With increase of d and {mu}, the E distribution becomes more uniform. Compared with DCCP system, PCCP system has much more uniform E distribution, costs less average current, and gains much better protection effects. Further, the mechanism of PCCP was analyzed. (authors)

  8. Hydrodenitrogenation mechanism of aromatic amines. Kinetic study and simulation

    International Nuclear Information System (INIS)

    D'Araujo, P.A.P.

    1994-06-01

    The decomposition of model molecules reacting alone or in competition was studied in a fixed bed reactor at 623 K and 7 MPa over a sulfided NiMo/Al 2 O 3 catalyst. The inhibiting effect of H 2 S and some nitrogen molecules, namely quinoline type compounds plays a major role in the transformation of anilines intermediates. On the other hand H 2 S acts as a cocatalyst and promote carbon-nitrogen bond cleavage, specially at low H 2 S partial pressure. When the H 2 S partial pressure is greater than the nitrogen compound partial pressure an inhibiting effect of H 2 S occurs and its promoting effect on carbon-nitrogen bond cleavage is cancelled. Hydrogen has a positive but moderate effect in hydrogenation steps. The mechanism of carbon-nitrogen bond scission depends on the structure of the nitrogen molecule namely on the hybridization of the carbon atom bearing the nitrogen atom. If the carbon a with respect to the nitrogen is monosubstituted the mechanism is essentially a nucleophilic substitution. When the degree of substitution increases the elimination mechanism becomes more important and the two mechanisms are in competition. With a sulfided catalyst, H 2 S from the gas phase doesn't change the importance of each mechanism, it just increases the rate of the reaction. In the presence of an oxide catalyst the contribution of the two mechanisms change. This result shows the importance of the sulphur species from the surface. Using isotopic exchange we could demonstrate that the sites able to dissociate H 2 S and H 2 are the same, and that the dissociation is of heterolytic nature. The kinetic modeling of hydrotreatment reactions using the CHEMKIN/SURFACE CHEMKIN package seems to be a convenient method in order to understand the kinetic and mechanistic phenomena in hydrodenitrogenation. The preliminary simulations in the case of 2.6 diethylaniline showed that only one type of site is not sufficient in order to account for the experimental results. Further simulations

  9. Mobile Smog Simulator: New Capabilities to Study Urban Mixtures

    Science.gov (United States)

    A smog simulator developed by EPA scientists and engineers has unique capabilities that will provide information for assessing the health impacts of relevant multipollutant atmospheres and identify contributions of specific sources.

  10. Application of CORSIKA Simulation Code to Study Lateral and ...

    Indian Academy of Sciences (India)

    J. Astrophys. ... and iron primary cosmic rays in different energies. ... distance to the shower axis, shape function of particles density, percentage of fluorescent light, ..... (c). Figure 2. Simulation results for proton primaries with other energies.

  11. Simulation study of radiation damage induced by energetic helium nuclei

    International Nuclear Information System (INIS)

    Hoang Dac Luc; Vo Tuong Hanh; Hoang Dac Dat

    2003-01-01

    High energy alpha particles produced by neutron-induced nuclear reactions can damage severely reactor materials. Simulation of this process is described using theoretical calculation and ion irradiation experiments at different displacement doses and Helium doses. (author)

  12. Simulation study of radiation damage induced by energetic helium nuclei

    CERN Document Server

    Hoang Dac Luc; Hoang Dac Dat

    2003-01-01

    High energy alpha particles produced by neutron-induced nuclear reactions can damage severely reactor materials. Simulation of this process is described using theoretical calculation and ion irradiation experiments at different displacement doses and Helium doses.

  13. A Theoretical Study of Subsurface Drainage Model Simulation of ...

    African Journals Online (AJOL)

    User

    Simulation of Drainage Flow and Leaching in Salt Affected ... mg/l with an impermeable layer at 10 m depth and impermeable field boundaries. .... The hydraulic where D is the free molecular diffusion ...... Dynamics of fluid in porous media.

  14. Visual simulation study of equipment maintenance in dangerous environment

    International Nuclear Information System (INIS)

    Zhu Bo; Yang Yanhua; Li Shiting

    2010-01-01

    The maintenance characteristics in dangerous environments are analyzed, and the application characteristics of visualized maintenance technology are introduced. The interactive method to implement maintenance simulation is presented using EON simulation platform. Then an interacted Virtual Maintenance Training System (VMTS) is further developed, and the composition and function are described in details. The VMTS can be used in extensive array of application scopes, and it is well compatible to the hardware of virtual reality. (author)

  15. The study, design and simulation of a free piston Stirling engine linear alternatorThe study, design and simulation of a free piston Stirling engine linear alternator

    Directory of Open Access Journals (Sweden)

    Teodora Susana Oros

    2014-12-01

    Full Text Available This paper presents a study, design and simulation of a Free Piston Stirling Engine Linear Alternator. There are presented the main steps of the magnetic and electric calculations for a permanent magnet linear alternator of fixed coil and moving magnets type. Finally, a detailed thermal, mechanical and electrical model for a Stirling engine linear alternator have been made in SIMULINK simulation program. The linear alternator simulation model uses a controllable DC voltage which simulates the linear alternator combined with a rectifier, a variable load and a DC-DC converter, which compensates for the variable nature of Stirling engine operation, and ensures a constant voltage output regardless of the load.

  16. A nodalization study of steam separator in real time simulation

    International Nuclear Information System (INIS)

    Horugshyang, Lein; Luh, R.T.J.; Zen-Yow, Wang

    1999-01-01

    The motive of this paper is to investigate the influence of steam separator nodalization on reactor thermohydraulics in terms of stability and level response. Three different nodalizations of steam separator are studied by using THEATRE and REMARK Code in a BWR simulator. The first nodalization is the traditional one with two nodes for steam separator. In this nodalization, the steam separation is modeled in the outer node, i.e., upper downcomer. Separated steam enters the Steen dome node and the liquid goes to the feedwater node. The second nodalization is similar to the first one with the steam separation modeled in the inner node. There is one additional junction connecting steam dome node and the inner node. The liquid fallback junction connects the inner node and feedwater node. The third nodalization is a combination of the former two with an integrated node for steam separator. Boundary conditions in this study are provided by a simplified feedwater and main steam driver. For comparison purpose, three tests including full power steady state initialisation, recirculation pumps runback and reactor scram are conducted. Major parameters such as reactor pressure, reactor level, void fractions, neutronic power and junction flows are recorded for analysis. Test results clearly show that the first nodalization is stable for steady state initialisation. However it has too responsive level performance in core flow reduction transients. The second nodalization is the closest representation of real plant structure, but not the performance. Test results show that an instability occurs in the separator region for both steady state initialisation and transients. This instability is caused by an unbalanced momentum in the dual loop configuration. The magnitude of the oscillation reduces as the power decreases. No superiority to the other nodalizations is shown in the test results. The third nodalization shows both stability and responsiveness in the tests. (author)

  17. Seventeenth Workshop on Computer Simulation Studies in Condensed-Matter Physics

    CERN Document Server

    Landau, David P; Schütler, Heinz-Bernd; Computer Simulation Studies in Condensed-Matter Physics XVI

    2006-01-01

    This status report features the most recent developments in the field, spanning a wide range of topical areas in the computer simulation of condensed matter/materials physics. Both established and new topics are included, ranging from the statistical mechanics of classical magnetic spin models to electronic structure calculations, quantum simulations, and simulations of soft condensed matter. The book presents new physical results as well as novel methods of simulation and data analysis. Highlights of this volume include various aspects of non-equilibrium statistical mechanics, studies of properties of real materials using both classical model simulations and electronic structure calculations, and the use of computer simulations in teaching.

  18. Pressure swing distillation of azeotropic mixture – A simulation study

    Directory of Open Access Journals (Sweden)

    Asma Iqbal

    2016-09-01

    Full Text Available The aim of this work is to simulate a pressure-swing distillation column for the separation and purification of ethanol from the ethanol–water binary system. The choice for this system is due to the importance of the ethanol–water separation. A steady-state equilibrium-stage model based on normalised MESH equations is used to simulate pressure-swing distillation column applied for the production of ethanol. All the work has been carried out using Aspen Plus simulator, version 13.2. Among the activity coefficient models available, the WILSON-RK model with binary parameters predicted by the Aspen Plus simulator is shown to be the most accurate to correlate the experimental vapor-/liquid equilibrium (VLE data available for the ethanol–water system. The simulation has been satisfactorily carried out for a mixture of 20 mol% ethanol in water at 1 atm pressure and 90 °C with a molar flow rate of 100 kmol/h. The adjusting parameters include D/F ratio and reflux ratio of the two columns to get water purity of 99.5 mol% from the bottom of the Low Pressure Column (LPC and the ethanol purity of 99.7 mol% from the bottom of High Pressure Column (HPC.

  19. Achievement of a training simulator for PWR power plant: application to control parametric studies

    International Nuclear Information System (INIS)

    Salomon-Sigogne, A.

    1982-09-01

    A simulation tool adapted to training tasks is developed. One presents the description of the simulator. One studies the management of a model by NEPTUN X2. A general description of a 900 MW PWR power station and the modelling of the power station are presented. The results obtained on the FIDIANE version of the simulator are finally analyzed [fr

  20. Sensitivity study on hydraulic well testing inversion using simulated annealing

    International Nuclear Information System (INIS)

    Nakao, Shinsuke; Najita, J.; Karasaki, Kenzi

    1997-11-01

    For environmental remediation, management of nuclear waste disposal, or geothermal reservoir engineering, it is very important to evaluate the permeabilities, spacing, and sizes of the subsurface fractures which control ground water flow. Cluster variable aperture (CVA) simulated annealing has been used as an inversion technique to construct fluid flow models of fractured formations based on transient pressure data from hydraulic tests. A two-dimensional fracture network system is represented as a filled regular lattice of fracture elements. The algorithm iteratively changes an aperture of cluster of fracture elements, which are chosen randomly from a list of discrete apertures, to improve the match to observed pressure transients. The size of the clusters is held constant throughout the iterations. Sensitivity studies using simple fracture models with eight wells show that, in general, it is necessary to conduct interference tests using at least three different wells as pumping well in order to reconstruct the fracture network with a transmissivity contrast of one order of magnitude, particularly when the cluster size is not known a priori. Because hydraulic inversion is inherently non-unique, it is important to utilize additional information. The authors investigated the relationship between the scale of heterogeneity and the optimum cluster size (and its shape) to enhance the reliability and convergence of the inversion. It appears that the cluster size corresponding to about 20--40 % of the practical range of the spatial correlation is optimal. Inversion results of the Raymond test site data are also presented and the practical range of spatial correlation is evaluated to be about 5--10 m from the optimal cluster size in the inversion

  1. Sensitivity study on hydraulic well testing inversion using simulated annealing

    Energy Technology Data Exchange (ETDEWEB)

    Nakao, Shinsuke; Najita, J.; Karasaki, Kenzi

    1997-11-01

    For environmental remediation, management of nuclear waste disposal, or geothermal reservoir engineering, it is very important to evaluate the permeabilities, spacing, and sizes of the subsurface fractures which control ground water flow. Cluster variable aperture (CVA) simulated annealing has been used as an inversion technique to construct fluid flow models of fractured formations based on transient pressure data from hydraulic tests. A two-dimensional fracture network system is represented as a filled regular lattice of fracture elements. The algorithm iteratively changes an aperture of cluster of fracture elements, which are chosen randomly from a list of discrete apertures, to improve the match to observed pressure transients. The size of the clusters is held constant throughout the iterations. Sensitivity studies using simple fracture models with eight wells show that, in general, it is necessary to conduct interference tests using at least three different wells as pumping well in order to reconstruct the fracture network with a transmissivity contrast of one order of magnitude, particularly when the cluster size is not known a priori. Because hydraulic inversion is inherently non-unique, it is important to utilize additional information. The authors investigated the relationship between the scale of heterogeneity and the optimum cluster size (and its shape) to enhance the reliability and convergence of the inversion. It appears that the cluster size corresponding to about 20--40 % of the practical range of the spatial correlation is optimal. Inversion results of the Raymond test site data are also presented and the practical range of spatial correlation is evaluated to be about 5--10 m from the optimal cluster size in the inversion.

  2. First Principle simulations of electrochemical interfaces - a DFT study

    DEFF Research Database (Denmark)

    Ahmed, Rizwan

    for the whole system to qualify as a proper electrochemical interface. I have also contributed to the model, which accounts for pH in the first principle electrode-electrolyte interface simulations. This is an important step forward, since electrochemical reaction rate and barrier for charge transfer can......In this thesis, I have looked beyond the computational hydrogen electrode (CHE) model, and focused on the first principle simulations which treats the electrode-electrolyte interfaces explicitly. Since obtaining a realistic electrode-electrolyte interface was difficult, I aimed to address various...... challenges regarding first principle electrochemical interface modeling in order to bridge the gap between the model interface used in simulations and real catalyst at operating conditions. Atomic scale insight for the processes and reactions that occur at the electrochemical interface presents a challenge...

  3. Solubility studies of Np(V) in simulated underground water

    International Nuclear Information System (INIS)

    Zhang Yingjie; Ren Lilong; Jiao Haiyang; Yao Jun; Su Xiguang; Fan Xianhua

    2004-01-01

    The solubility of Np(V) in simulated underground water has been measured with the variation of pH, storage time (0-100 days). All experiments were performed in an Ar glove box which contained high purity Ar, with an oxygen content of less than 5ppm. Experimental results show that the solubility of Np(V) in simulated underground water decreased with increasing pH value of solution; the solubility of Np(V) in simulated underground water determined at different pH is : pH=6.96, [Np(V)]=(3.52±0.37) x 10 -4 mol/L; pH=8.04, [Np(V)]=(8.24±0.32) x 10 -5 mol/L; pH=9.01, [Np(V)]=(3.04±0.48) x 10'- 5 mol/L, respectively. (author)

  4. A probabilistic cognitive simulator for HRA studies (PROCOS)

    International Nuclear Information System (INIS)

    Trucco, P.; Leva, M.C.

    2007-01-01

    The paper deals with the development of a simulator for approaching human errors in complex operational frameworks (e.g., plant commissioning). The aim is to integrate the quantification capabilities of the so-called 'first-generation' human reliability assessment (HRA) methods with a cognitive evaluation of the operator. The simulator allows analysing both error prevention and error recovery. It integrates cognitive human error analysis with standard hazard analysis methods (Hazop and event tree) by means of a 'semi static approach'. The comparison between the results obtained through the proposed approach and those of a traditional HRA method such as human error assessment and reduction technique, shows the capability of the simulator to provide coherent and accurate analysis

  5. Extremophiles survival to simulated space conditions: an astrobiology model study.

    Science.gov (United States)

    Mastascusa, V; Romano, I; Di Donato, P; Poli, A; Della Corte, V; Rotundi, A; Bussoletti, E; Quarto, M; Pugliese, M; Nicolaus, B

    2014-09-01

    In this work we investigated the ability of four extremophilic bacteria from Archaea and Bacteria domains to resist to space environment by exposing them to extreme conditions of temperature, UV radiation, desiccation coupled to low pressure generated in a Mars' conditions simulator. All the investigated extremophilic strains (namely Sulfolobus solfataricus, Haloterrigena hispanica, Thermotoga neapolitana and Geobacillus thermantarcticus) showed a good resistance to the simulation of the temperature variation in the space; on the other hand irradiation with UV at 254 nm affected only slightly the growth of H. hispanica, G. thermantarcticus and S. solfataricus; finally exposition to Mars simulated condition showed that H. hispanica and G. thermantarcticus were resistant to desiccation and low pressure.

  6. Simulation study on avoiding runaway electron generation by magnetic perturbations

    International Nuclear Information System (INIS)

    Tokuda, S.; Yoshino, R.; Matsumoto, T.; Hudson, S.R.; Kawano, Y.; Takizuka, T.

    2001-01-01

    Simulations have demonstrated that magnetic islands having the widths expected on the major disruption cause the collisionless loss of the relativistic electrons, and that the resultant loss rate is high enough to avoid or to suppress the runaway generation. It is because, for the magnetic fluctuations in the disruption, the loss of the electron confinement due to the breakdown of the toroidal momentum conservation overwhelms the runaway electron confinement due to the phase-averaging effect of relativistic electrons. Simulation results agree closely with recent experiments on fast plasma shutdown, showing that it is possible to prevent the generation of runaway electrons. (author)

  7. Simulation and study of small numbers of random events

    Science.gov (United States)

    Shelton, R. D.

    1986-01-01

    Random events were simulated by computer and subjected to various statistical methods to extract important parameters. Various forms of curve fitting were explored, such as least squares, least distance from a line, maximum likelihood. Problems considered were dead time, exponential decay, and spectrum extraction from cosmic ray data using binned data and data from individual events. Computer programs, mostly of an iterative nature, were developed to do these simulations and extractions and are partially listed as appendices. The mathematical basis for the compuer programs is given.

  8. Molecular Dynamics Simulation Studies of Caffeine Aggregation in Aqueous Solution

    OpenAIRE

    Tavagnacco, Letizia; Schnupf, Udo; Mason, Philip E.; Saboungi, Marie-Louise; Cesàro, Attilio; Brady, John W.

    2011-01-01

    Molecular dynamics simulations were carried out on a system of eight independent caffeine molecules in a periodic box of water at 300 K, representing a solution near the solubility limit for caffeine at room temperature, using a newly-developed CHARMM-type force field for caffeine in water. Simulations were also conducted for single caffeine molecules in water using two different water models (TIP3P and TIP4P). Water was found to structure in a complex fashion around the planar caffeine molec...

  9. A Simulation Study of the Virtual Interface Architecture

    International Nuclear Information System (INIS)

    Hu, Tan Chang; Stans, Leonard; Tarman, Thomas D.

    1999-01-01

    The Virtual Interface Architecture (VIA) is an emerging standard for interconnecting commodity computing nodes into a cluster. Since VIA protocol. operations are implemented outside the operating system kernel (often, entirely in hardware), VIA transfers can be performed at very low delay, high throughput, and minimal CPU overhead. This makes VIA ideal when building large clusters that perform complex simulations of physical events, However, the scaling properties of VIA are less clear. This paper describes the design and results of a simulation model developed in OPNET to investigate VIA's ability to scale to clusters of> 1000 nodes

  10. Digital filter algorithm study and simulation of SSRF feedback system

    International Nuclear Information System (INIS)

    Han Lifeng; Yuan Renxian; Ye Kairong

    2008-01-01

    Least Square Fitting was used to design a FIR filter of the transverse feedback system for the Shanghai Synchrotron Radiation Facility (SSRF). The algorithm helped us to set appropriate gain and phase at special frequency points. This reduced the power needed for damping the beam oscillations, which was proved by System View signal simulation. And with AT (Accelerator Tool) simulation, the Gain calculation and settings to the output signals from the FIR filter were deduced. The relationship between the Kicker power and the system damping time was also given. (authors)

  11. Simulation study for the nuclear matter below the saturation density

    International Nuclear Information System (INIS)

    Kido, Toshihiko; Maruyama, Toshiki; Chiba, Satoshi; Niita, Koji

    1999-01-01

    The infinite nuclear matter that consists of numerous protons and neutrons is described by using periodic boundary conditions. The motion of each nucleon in the fundamental cell is decided by a Molecular Dynamics. The ground states or the excited states of the nuclear matter are simulated. (author)

  12. Business Profitability: A Simulation Study of Personalities and Organizational Success.

    Science.gov (United States)

    Carsrud, A. L.; And Others

    There is no clearly established link between business success and the personality characteristics of the individual. To investigate the effect of the personalities of potential entrepreneurs/business owners on success, college senior business administration majors (N=152) participted in a business simulation game. Subjects first completed the Work…

  13. Climate change and international tourism: A simulation study

    NARCIS (Netherlands)

    Hamilton, J.M.; Maddison, D.J.; Tol, R.S.J.

    2005-01-01

    The literature on tourism and climate change lacks an analysis of the global changes in tourism demand. Here, a simulation model of international tourism is presented that fills that gap. The current pattern of international tourist flows is modelled using 1995 data on departures and arrivals for

  14. Contribution to study and design of PWR plant simulation code

    International Nuclear Information System (INIS)

    Delourme, Didier.

    1980-11-01

    This paper presents an improvement of PICOLO, a package for PWR plants simulation. Its describes principally the integration to the code of a primary loop and pressurizer model and the corresponding control loops. Fast transients are tested on the packages and results are compared with real transients obtained on plants [fr

  15. Theory, simulation, and experimental studies of zonal flows

    International Nuclear Information System (INIS)

    Hahm, T. S.; Burrell, K.H.; Lin, Z.; Nazikian, R.; Synakowski, E.J.

    2000-01-01

    The authors report on current theoretical understanding of the characteristics of self-generated zonal flows as observed in nonlinear gyrokinetic simulations of toroidal ITG turbulence [Science 281, 1835 (1998)], and discuss various possibilities for experimental measurements of signature of zonal flows

  16. improving clinical practice through simulation: a case study of ...

    African Journals Online (AJOL)

    PROF. BARTH EKWEME

    students' perceptions of clinical simulation as a teaching/learning method to increase ... lack is reported to impact on students negatively as they ... care systems and information technology have reduced .... skilled, they become more confident and more motivated .... for achieving long-term retention of clinical competency.

  17. Soil Erosion Study through Simulation: An Educational Tool.

    Science.gov (United States)

    Huber, Thomas P.; Falkenmayer, Karen

    1987-01-01

    Discusses the need for education about soil erosion and advocates the use of the Universal Soil Loss Equation (USLE) to show the impacts of human and natural action on the land. Describes the use of a computer simulated version of the USLE in several environmental and farming situations. (TW)

  18. Computer simulation study of water using a fluctuating charge model

    Indian Academy of Sciences (India)

    Unknown

    Typically, the simulated diffusion constants are larger, and relaxation times smaller than .... where λi is the Lagrange multiplier for the charge neutrality constraint. As the .... For a geometrically rigid model such as SPC, the integral turns out to ...

  19. Decoding the dopamine signal in macaque prefrontal cortex: a simulation study using the Cx3Dp simulator.

    Directory of Open Access Journals (Sweden)

    Isabelle Ayumi Spühler

    Full Text Available Dopamine transmission in the prefrontal cortex plays an important role in reward based learning, working memory and attention. Dopamine is thought to be released non-synaptically into the extracellular space and to reach distant receptors through diffusion. This simulation study examines how the dopamine signal might be decoded by the recipient neuron. The simulation was based on parameters from the literature and on our own quantified, structural data from macaque prefrontal area 10. The change in extracellular dopamine concentration was estimated at different distances from release sites and related to the affinity of the dopamine receptors. Due to the sparse and random distribution of release sites, a transient heterogeneous pattern of dopamine concentration emerges. Our simulation predicts, however, that at any point in the simulation volume there is sufficient dopamine to bind and activate high-affinity dopamine receptors. We propose that dopamine is broadcast to its distant receptors and any change from the local baseline concentration might be decoded by a transient change in the binding probability of dopamine receptors. Dopamine could thus provide a graduated 'teaching' signal to reinforce concurrently active synapses and cell assemblies. In conditions of highly reduced or highly elevated dopamine levels the simulations predict that relative changes in the dopamine signal can no longer be decoded, which might explain why cognitive deficits are observed in patients with Parkinson's disease, or induced through drugs blocking dopamine reuptake.

  20. Decoding the Dopamine Signal in Macaque Prefrontal Cortex: A Simulation Study Using the Cx3Dp Simulator

    Science.gov (United States)

    Spühler, Isabelle Ayumi; Hauri, Andreas

    2013-01-01

    Dopamine transmission in the prefrontal cortex plays an important role in reward based learning, working memory and attention. Dopamine is thought to be released non-synaptically into the extracellular space and to reach distant receptors through diffusion. This simulation study examines how the dopamine signal might be decoded by the recipient neuron. The simulation was based on parameters from the literature and on our own quantified, structural data from macaque prefrontal area 10. The change in extracellular dopamine concentration was estimated at different distances from release sites and related to the affinity of the dopamine receptors. Due to the sparse and random distribution of release sites, a transient heterogeneous pattern of dopamine concentration emerges. Our simulation predicts, however, that at any point in the simulation volume there is sufficient dopamine to bind and activate high-affinity dopamine receptors. We propose that dopamine is broadcast to its distant receptors and any change from the local baseline concentration might be decoded by a transient change in the binding probability of dopamine receptors. Dopamine could thus provide a graduated ‘teaching’ signal to reinforce concurrently active synapses and cell assemblies. In conditions of highly reduced or highly elevated dopamine levels the simulations predict that relative changes in the dopamine signal can no longer be decoded, which might explain why cognitive deficits are observed in patients with Parkinson’s disease, or induced through drugs blocking dopamine reuptake. PMID:23951205

  1. Computer Simulation Studies of Ion Channels at High Temperatures

    Science.gov (United States)

    Song, Hyun Deok

    The gramicidin channel is the smallest known biological ion channel, and it exhibits cation selectivity. Recently, Dr. John Cuppoletti's group at the University of Cincinnati showed that the gramicidin channel can function at high temperatures (360 ˜ 380K) with significant currents. This finding may have significant implications for fuel cell technology. In this thesis, we have examined the gramicidin channel at 300K, 330K, and 360K by computer simulation. We have investigated how the temperature affects the current and differences in magnitude of free energy between the two gramicidin forms, the helical dimer (HD) and the double helix (DH). A slight decrease of the free energy barrier inside the gramicidin channel and increased diffusion at high temperatures result in an increase of current. An applied external field of 0.2V/nm along the membrane normal results in directly observable ion transport across the channels at high temperatures for both HD and DH forms. We found that higher temperatures also affect the probability distribution of hydrogen bonds, the bending angle, the distance between dimers, and the size of the pore radius for the helical dimer structure. These findings may be related to the gating of the gramicidin channel. Methanococcus jannaschii (MJ) is a methane-producing thermophile, which was discovered at a depth of 2600m in a Pacific Ocean vent in 1983. It has the ability to thrive at high temperatures and high pressures, which are unfavorable for most life forms. There have been some experiments to study its stability under extreme conditions, but still the origin of the stability of MJ is not exactly known. MJ0305 is the chloride channel protein from the thermophile MJ. After generating a structure of MJ0305 by homology modeling based on the Ecoli ClC templates, we examined the thermal stability, and the network stability from the change of network entropy calculated from the adjacency matrices of the protein. High temperatures increase the

  2. Why is the Magellanic Stream so Turbulent? - A Simulational Study

    Science.gov (United States)

    Williams, Elliott; Shelton, Robin L.

    2018-06-01

    As the Large and Small Magellanic Clouds travel through the Milky Way (MW) halo, gas is tidally and ram pressure stripped from them, forming the Leading Arm (LA) and Magellanic Stream (MS). The evolution of the LA and MS are an interest to astronomers because there is evidence that the diffuse gas that has been stripped off is able to fall onto the galactic disk and cool enough to fuel star formation in the MW. For et al, 2014 published a catalog of 251 high velocity clouds (HVCs) in the MS, many of which have head-tail morphologies, suggesting interaction with the Milky Way’s halo or other gas in the MS. For et al noticed that the pointing direction of the HVCs are random, which they interpreted as an indication of strong turbulence. They suggested the shock cascade scenario as a contributing process, where ablated cloud material generates turbulence (and H-alpha emission). We take a closer look at this process via simulations. We ran numerical simulations of clouds in the MS using the University of Chicago’s FLASH software. We simulated cases that had two clouds, where one trailed behind the other, and we simulated cases that had one cloud in order to examine the effects of drafting on cloud dynamics and velocity dispersion. Initial cloud temperatures ranged from 100 K to 20,000 K. We have created velocity dispersion maps from the FLASH simulation data to visualize turbulence. We compare these generated maps with 21 cm observations (most recently Westmeier, 2017), in order to search for signatures similar to the small scale turbulence seen in the simulations. We find that if the clouds are initially near to each other, then drafting allows the trailing cloud to catch the leading cloud and mix together. For greater separations, Kelvin-Helmholtz instabilities disrupt the clouds enough before impact that drafting has a minimal role. Our velocity dispersion maps of the warmer clouds closely match values published in For et al, 2014; although, thermal broadening

  3. Study on multipartite quantum states: preparation, simulation, and characterization

    International Nuclear Information System (INIS)

    Kruszynska, C.

    2009-01-01

    In this thesis different problems are investigated related to the description as well as the manipulation of multipartite quantum states. Because of the superposition principle, the state of a composite quantum system can be entangled, i.e. exhibit quantum correlations between the sites. The entanglement of two-qubit systems is well understood. There is only one kind of entanglement which can be directly related to the value of the Schmidt coefficients. However this is not the case for multipartite entanglement of qubit systems. Unlike in the two-qubit case, a multipartite quantum state can be entangled in many different ways, which complicates the classification and characterization of such states. The storage and manipulation of a quantum state is a challenging task because of the decoherence resulting from the interaction of the state with its environment. One way to overcome this difficulty is to use entanglement purification which will be the subject of the first part of this thesis. Entanglement purification allows to extract a small number of nearly pure states out of a bigger set of mixed states. We review existing bipartite and multipartite entanglement purification protocols and introduce new protocols which are capable of purifying any graph state, enlarging by this the class of states which can be purified. The second part deals with the preparation and distribution of high-fidelity multi-party entangled states via noisy channels and operations. In the particular case of GHZ and cluster states, we study different strategies using bipartite or multipartite purification protocols. The most efficient strategy depends on the target fidelity one wishes to achieve and on the quality of transmission channel and local operations. We show the existence of a crossing point beyond which the strategy making use of the purification of the state as a whole is more efficient than a strategy in which pairs are purified before they are connected to the final state. We

  4. A study on the creep characteristics of simulated DUPIC fuel

    International Nuclear Information System (INIS)

    Kang, Kweon Ho; Ryu, H. J.; Kim, H. S.; Song, K. C.; Yang, M. S.; Na, S.

    2001-09-01

    Compression creep test was performed using simulated DUPIC fuel in the temperature range from 1773 to 1973 K under the stress range of 21 - 60 MPa. Creep rate and the activation energy were obtained. The activation energy for creep was 649.35 - 675.94 kJ/mol at the low stress region, where creep mechanism was controlled by diffusion. On the other hand, the activation energy at high stress region was 750.68 - 792.18 kJ/mol, where creep mechanism was controlled by dislocation motion. The activation energy for dislocation creep was higher than that for diffusion creep. The activation energy of reference simulated DUPIC fuel was higher than that of UO2

  5. Study of the Time Response of a Simulated Hydroelectric System

    International Nuclear Information System (INIS)

    Simani, S; Alvisi, S; Venturini, M

    2014-01-01

    This paper addresses the design of an advanced control strategy for a typical hydroelectric dynamic process, performed in the Matlab and Simulink environments. The hydraulic system consists of a high water head and a long penstock with upstream and downstream surge tanks, and is equipped with a Francis turbine. The nonlinear characteristics of hydraulic turbine and the inelastic water hammer effects were considered to calculate and simulate the hydraulic transients. With reference to the control solution, the proposed methodology relies on an adaptive control designed by means of the on-line identification of the system model under monitoring. Extensive simulations and comparison with respect to a classic hydraulic turbine speed PID regulator show the effectiveness of the proposed modelling and control tools

  6. Simulation studies of macroparticles falling into the LHC Proton Beam

    CERN Document Server

    Fuster Martinez, N; Zimmermann, F; Baer, T; Giovannozzi, M; Holzer, E B; Nebot Del Busto, E; Nordt, A; Sapinski, M; Yang, Z

    2011-01-01

    We report updated simulations on the interaction of macroparticles falling from the top of the vacuum chamber into the circulating LHC proton beam. The path and charge state of micron size micro-particles are computed together with the resulting beam losses, which — if high enough — can lead to the local quench of superconducting (SC) magnets. The simulated time evolution of the beam loss is compared with observations in order to constrain some macroparticle parameters. We also discuss the possibility of a “multiple crossing” by the same macroparticle, the effect of a strong dipole field, and the dependence of peak loss rate and loss duration on beam current and on beam size.

  7. Positron annihilation lifetime spectroscopy source correction determination: A simulation study

    Energy Technology Data Exchange (ETDEWEB)

    Kanda, Gurmeet S.; Keeble, David J., E-mail: d.j.keeble@dundee.ac.uk

    2016-02-01

    Positron annihilation lifetime spectroscopy (PALS) can provide sensitive detection and identification of vacancy-related point defects in materials. These measurements are normally performed using a positron source supported, and enclosed by, a thin foil. Annihilation events from this source arrangement must be quantified and are normally subtracted from the spectrum before analysis of the material lifetime components proceeds. Here simulated PALS spectra reproducing source correction evaluation experiments have been systematically fitted and analysed using the packages PALSfit and MELT. Simulations were performed assuming a single lifetime material, and for a material with two lifetime components. Source correction terms representing a directly deposited source and various foil supported sources were added. It is shown that in principle these source terms can be extracted from suitably designed experiments, but that fitting a number of independent, nominally identical, spectra is recommended.

  8. Study of the Time Response of a Simulated Hydroelectric System

    Science.gov (United States)

    Simani, S.; Alvisi, S.; Venturini, M.

    2014-12-01

    This paper addresses the design of an advanced control strategy for a typical hydroelectric dynamic process, performed in the Matlab and Simulink environments. The hydraulic system consists of a high water head and a long penstock with upstream and downstream surge tanks, and is equipped with a Francis turbine. The nonlinear characteristics of hydraulic turbine and the inelastic water hammer effects were considered to calculate and simulate the hydraulic transients. With reference to the control solution, the proposed methodology relies on an adaptive control designed by means of the on-line identification of the system model under monitoring. Extensive simulations and comparison with respect to a classic hydraulic turbine speed PID regulator show the effectiveness of the proposed modelling and control tools.

  9. Simulation Study on Freeze-drying Characteristics of Mashed Beef

    OpenAIRE

    Tambunan, Armansyah H; Solahudin, M; Rahajeng, Estri

    2000-01-01

    Drying characteristic of a particular product is important in analyzing the appropriateness of the drying method for the product. This is especially important for freeze drying, which is known as the most expensive drying method, asideji-om its good drying quality. The objectives of this experiment are to develop a computer simulation program using a retreating drying-frontmodel for predicting freeze drying characteristics of mashed nteat, especially for the influence of sublimation temperatu...

  10. A study on naphtha catalytic reforming reactor simulation and analysis.

    Science.gov (United States)

    Liang, Ke-min; Guo, Hai-yan; Pan, Shi-wei

    2005-06-01

    A naphtha catalytic reforming unit with four reactors in series is analyzed. A physical model is proposed to describe the catalytic reforming radial flow reactor. Kinetics and thermodynamics equations are selected to describe the naphtha catalytic reforming reactions characteristics based on idealizing the complex naphtha mixture by representing the paraffin, naphthene, and aromatic groups by single compounds. The simulation results based above models agree very well with actual operation unit data.

  11. A study on naphtha catalytic reforming reactor simulation and analysis

    OpenAIRE

    Liang, Ke-min; Guo, Hai-yan; Pan, Shi-wei

    2005-01-01

    A naphtha catalytic reforming unit with four reactors in series is analyzed. A physical model is proposed to describe the catalytic reforming radial flow reactor. Kinetics and thermodynamics equations are selected to describe the naphtha catalytic reforming reactions characteristics based on idealizing the complex naphtha mixture by representing the paraffin, naphthene, and aromatic groups by single compounds. The simulation results based above models agree very well with actual operation uni...

  12. Sequence-dependent DNA deformability studied using molecular dynamics simulations.

    Science.gov (United States)

    Fujii, Satoshi; Kono, Hidetoshi; Takenaka, Shigeori; Go, Nobuhiro; Sarai, Akinori

    2007-01-01

    Proteins recognize specific DNA sequences not only through direct contact between amino acids and bases, but also indirectly based on the sequence-dependent conformation and deformability of the DNA (indirect readout). We used molecular dynamics simulations to analyze the sequence-dependent DNA conformations of all 136 possible tetrameric sequences sandwiched between CGCG sequences. The deformability of dimeric steps obtained by the simulations is consistent with that by the crystal structures. The simulation results further showed that the conformation and deformability of the tetramers can highly depend on the flanking base pairs. The conformations of xATx tetramers show the most rigidity and are not affected by the flanking base pairs and the xYRx show by contrast the greatest flexibility and change their conformations depending on the base pairs at both ends, suggesting tetramers with the same central dimer can show different deformabilities. These results suggest that analysis of dimeric steps alone may overlook some conformational features of DNA and provide insight into the mechanism of indirect readout during protein-DNA recognition. Moreover, the sequence dependence of DNA conformation and deformability may be used to estimate the contribution of indirect readout to the specificity of protein-DNA recognition as well as nucleosome positioning and large-scale behavior of nucleic acids.

  13. Magnetohydrodynamic Simulations for Studying Solar Flare Trigger Mechanism

    Energy Technology Data Exchange (ETDEWEB)

    Muhamad, J.; Kusano, K.; Inoue, S.; Shiota, D. [Institute for Space-Earth Environmental Research, Nagoya University, Furocho, Chikusa-ku, Nagoya, Aichi, 464-8601 (Japan)

    2017-06-20

    In order to understand the flare trigger mechanism, we conduct three-dimensional magnetohydrodynamic simulations using a coronal magnetic field model derived from data observed by the Hinode satellite. Several types of magnetic bipoles are imposed into the photospheric boundary of the Nonlinear Force-free Field model of Active Region (AR) NOAA 10930 on 2006 December 13, to investigate what kind of magnetic disturbance may trigger the flare. As a result, we confirm that certain small bipole fields, which emerge into the highly sheared global magnetic field of an AR, can effectively trigger a flare. These bipole fields can be classified into two groups based on their orientation relative to the polarity inversion line: the so-called opposite polarity, and reversed shear structures, as suggested by Kusano et al. We also investigate the structure of the footpoints of reconnected field lines. By comparing the distribution of reconstructed field lines and observed flare ribbons, the trigger structure of the flare can be inferred. Our simulation suggests that the data-constrained simulation, taking into account both the large-scale magnetic structure and small-scale magnetic disturbance (such as emerging fluxes), is a good way to discover a flare-producing AR, which can be applied to space weather prediction.

  14. A study for production simulation model generation system based on data model at a shipyard

    Directory of Open Access Journals (Sweden)

    Myung-Gi Back

    2016-09-01

    Full Text Available Simulation technology is a type of shipbuilding product lifecycle management solution used to support production planning or decision-making. Normally, most shipbuilding processes are consisted of job shop production, and the modeling and simulation require professional skills and experience on shipbuilding. For these reasons, many shipbuilding companies have difficulties adapting simulation systems, regardless of the necessity for the technology. In this paper, the data model for shipyard production simulation model generation was defined by analyzing the iterative simulation modeling procedure. The shipyard production simulation data model defined in this study contains the information necessary for the conventional simulation modeling procedure and can serve as a basis for simulation model generation. The efficacy of the developed system was validated by applying it to the simulation model generation of the panel block production line. By implementing the initial simulation model generation process, which was performed in the past with a simulation modeler, the proposed system substantially reduced the modeling time. In addition, by reducing the difficulties posed by different modeler-dependent generation methods, the proposed system makes the standardization of the simulation model quality possible.

  15. Feasibility study for a computerized emergency preparedness simulation facility

    International Nuclear Information System (INIS)

    Gerhardstein, L.H.; Schroeder, J.O.; Sandusky, W.F.

    1979-11-01

    This report details the feasibility of a computerized Emergency Preparedness Simulation Facility (EPSF) for use by the Nuclear Regulatory Commission (NRC). The proposed facility would be designed to provide the NRC and other federal, state, and local government agencies with a capability to formulate, test, and evaluate the Emergency Preparedness Plans (EPP) which local and state agencies have/will establish for use during nuclear emergencies. In cases of any state emergency (including a nuclear emergency), high level state government officials will direct emergency procedures and insure that state and local emergency teams carry out tasks which have been established in their EPP. When an emergency exists, rapid mobilization of emergency teams, efficient communication, and effective coordination of individual team efforts is essential to safety, preservation of property, and overall public welfare. Current EPP evaluation procedures are qualitative in nature and while they do compare emergency drill performance with the EPP, the nature of the drills often does not provide enough realism to actual emergency conditions. Automated simulation of real emergency conditions using modern computer equipment and programming techniques will provide the NRC emergency evaluation teams a simulated environment which closely approximates conditions which would actually exist during a real emergency. In addition, the computer can be used to collect and log performance and event data which will aid the evaluation team in making assessments of the state or local area's EPP and their Emergency Preparedness Teams performance during emergency drills. Overall, a computerized EPSF can improve drill testing and evaluation efficiency, provide approximate emergency condition realism, and improve public awareness of local emergency procedures

  16. Molecular dynamics simulation studies of tailored nanostructured polymers

    Science.gov (United States)

    Liu, Lixin

    With recent advancements in the synthesis and characterization of polymeric materials, scientists are able to create multi-scale novel polymers with various cases of chemical functionalities, diversified topologies, as well as cross-linking networks. Due to those remarkable achievements, there are a broad range of possible applications of smart polymers in catalysis, in environmental remediation, and especially in drug-delivery. Because of rising interest in developing therapeutic drug binding to specific treating target, polymer chemists are in particular interests in design and engineering the drug delivery materials to be not only bio-compatible, but also to be capable of self-assembly at various in-vivo physiological stimulus. Both experimental and theoretical work indicate that the thermodynamic properties relating to the hydrophobic effect play an important role in determining self-assembly process. At the same time, computational simulation and modeling are powerful instruments to contribute to microscopic thermodynamics' understanding toward self-assembly phenomenon. Along with statistical approaches, constructing empirical model based on simulation results would also help predict for further development of tailored nano-structured materials. My Research mainly focused on investigating physical and chemical characteristics of polymer materials through molecular dynamics simulation and probing the fundamental thermodynamic driving force of self-assembly behavior. We tried to surmount technological obstacles in computational chemistry and build an efficient scheme to identify the physical and chemical Feature of molecules, to reproduce underlying properties, to understand the origin of thermodynamic signatures, and to speed up current trial and error process in screening new materials.

  17. Molecular simulation studies on thermophysical properties with application to working fluids

    CERN Document Server

    Raabe, Gabriele

    2017-01-01

    This book discusses the fundamentals of molecular simulation, starting with the basics of statistical mechanics and providing introductions to Monte Carlo and molecular dynamics simulation techniques. It also offers an overview of force-field models for molecular simulations and their parameterization, with a discussion of specific aspects. The book then summarizes the available know-how for analyzing molecular simulation outputs to derive information on thermophysical and structural properties. Both the force-field modeling and the analysis of simulation outputs are illustrated by various examples. Simulation studies on recently introduced HFO compounds as working fluids for different technical applications demonstrate the value of molecular simulations in providing predictions for poorly understood compounds and gaining a molecular-level understanding of their properties. This book will prove a valuable resource to researchers and students alike.

  18. Large Blast and Thermal Simulator Reflected Wave Eliminator Study

    Science.gov (United States)

    1990-03-01

    it delays the passage of this wave through the test section until after the test is complete. The required length of extra duct depends on the strength...tube axis, which acts like an additional contraction effect since Se = Sj/[Cqsin(aj)]. Tii extra area is illustrated best by plotting (Se-Ae)/Ac versus...34Simulation de Choc et de Soaffie. Comimpensateur d’Ondes de Detente de Bouche pour tube a Choc de 2400 mm de diametre de Veine. Description, Compte- Renda

  19. Climate change and international tourism: a simulation study

    Energy Technology Data Exchange (ETDEWEB)

    Hamilton, J.M. [University of Hamburg (Germany). Centre for Marine and Climate Research, Research Unit Sustainability and Global Change; Maddison, D.J. [University of Southern Denmark, Odense (Denmark). Economics Institute; Centre for Cultural Economics and Management, London (United Kingdom); Tol, R.S.J. [University of Hamburg (Germany). Centre for Marine and Climate Research, Research Unit Sustainability and Global Change; Vrije Universiteit, Amsterdam (Netherlands). Institute for Environmental Studies; Carnegie Mellon University, Pittsburgh (United States). Center for Integrated Study of the Human Dimensions of Global Change

    2005-10-01

    The literature on tourism and climate change lacks an analysis of the global changes in tourism demand. Here, a simulation model of international tourism is presented that fills that gasp. The current pattern of international tourist flows is modelled using 1995 data on departures and arrivals for 207 countries. Using this basic model the impact on arrivals and departures through changes un population, per capita income and climate change are analysed. In the medium to long term, tourism will grow, however, the change from climate change is smaller than from population and income changes. (author)

  20. HCIT Contrast Performance Sensitivity Studies: Simulation Versus Experiment

    Science.gov (United States)

    Sidick, Erkin; Shaklan, Stuart; Krist, John; Cady, Eric J.; Kern, Brian; Balasubramanian, Kunjithapatham

    2013-01-01

    Using NASA's High Contrast Imaging Testbed (HCIT) at the Jet Propulsion Laboratory, we have experimentally investigated the sensitivity of dark hole contrast in a Lyot coronagraph for the following factors: 1) Lateral and longitudinal translation of an occulting mask; 2) An opaque spot on the occulting mask; 3) Sizes of the controlled dark hole area. Also, we compared the measured results with simulations obtained using both MACOS (Modeling and Analysis for Controlled Optical Systems) and PROPER optical analysis programs with full three-dimensional near-field diffraction analysis to model HCIT's optical train and coronagraph.

  1. Simulation study of two-ion hybrid resonance heating

    International Nuclear Information System (INIS)

    Riyopoulos, S.; Tajima, T.

    1986-02-01

    A one-dimensional low-noise, low-frequency electromagnetic particle simulation code that is appropriate for investigation of ion cyclotron resonance heating (ICRH) is developed. Retaining the hyperbolicity of the electromagnetic waves and exploiting nearly one-dimensional characteristics (perpendicular to the external magnetic field) of the ICRH, we use the guiding center electron approximation for the transverse electronic current calculation. We observe mode conversion of the incoming magnetosonic wave into the electrostatic ion-ion hybrid mode accompanied by strong ion-heating. The dependence of this heating on the different plasma parameters is examined through a series of simulations, focusing mainly on wave incidence from the high field side. Because K/sub parallel/ = 0 in our runs, the conventional Landau damping cannot explain the ion heating. Non-linear mechanisms for energy transfer are discussed. Our numerical results demonstrate the importance of the non-linear wave particle interaction for energy transfer are discussed. Our numerical results demonstrate the importance of the non-linear wave particle interaction for energy absorption during radio frequency heating in the ion cyclotron regime. 32 refs., 17 figs

  2. Molecular dynamics simulation studies of caffeine aggregation in aqueous solution.

    Science.gov (United States)

    Tavagnacco, Letizia; Schnupf, Udo; Mason, Philip E; Saboungi, Marie-Louise; Cesàro, Attilio; Brady, John W

    2011-09-22

    Molecular dynamics simulations were carried out on a system of eight independent caffeine molecules in a periodic box of water at 300 K, representing a solution near the solubility limit for caffeine at room temperature, using a newly developed CHARMM-type force field for caffeine in water. Simulations were also conducted for single caffeine molecules in water using two different water models (TIP3P and TIP4P). Water was found to structure in a complex fashion around the planar caffeine molecules, which was not sensitive to the water model used. As expected, extensive aggregation of the caffeine molecules was observed, with the molecules stacking their flat faces against one another like coins, with their methylene groups staggered to avoid steric clashes. A dynamic equilibrum was observed between large n-mers, including stacks with all eight solute molecules, and smaller clusters, with the calculated osmotic coefficient being in acceptable agreement with the experimental value. The insensitivity of the results to water model and the congruence with experimental thermodynamic data suggest that the observed stacking interactions are a realistic representation of the actual association mechanism in aqueous caffeine solutions.

  3. Short-duration Electron Precipitation Studied by Test Particle Simulation

    Directory of Open Access Journals (Sweden)

    Jaejin Lee

    2015-12-01

    Full Text Available Energy spectra of electron microbursts from 170 keV to 340 keV have been measured by the solid-state detectors aboard the low-altitude (680 km polar-orbiting Korean STSAT-1 (Science and Technology SATellite. These measurements have revealed two important characteristics unique to the microbursts: (1 They are produced by a fast-loss cone-filling process in which the interaction time for pitch-angle scattering is less than 50 ms and (2 The e-folding energy of the perpendicular component is larger than that of the parallel component, and the loss cone is not completely filled by electrons. To understand how wave-particle interactions could generate microbursts, we performed a test particle simulation and investigated how the waves scattered electron pitch angles within the timescale required for microburst precipitation. The application of rising-frequency whistler-mode waves to electrons of different energies moving in a dipole magnetic field showed that chorus magnetic wave fields, rather than electric fields, were the main cause of microburst events, which implied that microbursts could be produced by a quasi-adiabatic process. In addition, the simulation results showed that high-energy electrons could resonate with chorus waves at high magnetic latitudes where the loss cone was larger, which might explain the decreased e-folding energy of precipitated microbursts compared to that of trapped electrons.

  4. Study of Hydrokinetic Turbine Arrays with Large Eddy Simulation

    Science.gov (United States)

    Sale, Danny; Aliseda, Alberto

    2014-11-01

    Marine renewable energy is advancing towards commercialization, including electrical power generation from ocean, river, and tidal currents. The focus of this work is to develop numerical simulations capable of predicting the power generation potential of hydrokinetic turbine arrays-this includes analysis of unsteady and averaged flow fields, turbulence statistics, and unsteady loadings on turbine rotors and support structures due to interaction with rotor wakes and ambient turbulence. The governing equations of large-eddy-simulation (LES) are solved using a finite-volume method, and the presence of turbine blades are approximated by the actuator-line method in which hydrodynamic forces are projected to the flow field as a body force. The actuator-line approach captures helical wake formation including vortex shedding from individual blades, and the effects of drag and vorticity generation from the rough seabed surface are accounted for by wall-models. This LES framework was used to replicate a previous flume experiment consisting of three hydrokinetic turbines tested under various operating conditions and array layouts. Predictions of the power generation, velocity deficit and turbulence statistics in the wakes are compared between the LES and experimental datasets.

  5. Simulation studies for the PANDA endcap disc DIRC

    Energy Technology Data Exchange (ETDEWEB)

    Schmidt, Mustafa; Biguenko, Klim; Dueren, Michael; Hayrapetyan, Avetik; Kroeck, Benno; Merle, Oliver; Rieke, Julian [II. Physikalisches Institut, Justus-Liebig-Universitaet, Giessen (Germany); Foehl, Klaus [CERN, Genf (Switzerland); Collaboration: PANDA-Collaboration

    2015-07-01

    The physics program of the PANDA detector at the future FAIR facility at GSI requires excellent particle identification. For the Panda forward endcap region a novel detector type called ''Disc DIRC'' has been designed. It covers the angular range between 5 and 22 degrees and uses internally reflected Cherenkov light in order to separate pions, kaons and protons up to a momentum of 4 GeV/c. During the design phase, extensive detector simulations have been performed to optimize and evaluate the design. The simulations were done using Geant4 and the PandaRoot framework in addition with a dedicated reconstruction software. An important aspect was the optimization of the imaging while taking the geometrical tolerances of the manufacturing process of the final detector into account. The main focus lies on the optimization process of the cylindrical and polynomial focussing optics at the edges of the detector plate, which has been performed with the merit function of a raytracer called PyOptics, written by one of the group members.

  6. Statistical Analysis of Large Simulated Yield Datasets for Studying Climate Effects

    NARCIS (Netherlands)

    Makowski, D.; Asseng, S.; Ewert, F.; Bassu, S.; Durand, J.L.; Martre, P.; Adam, M.; Aggarwal, P.K.; Angulo, C.; Baron, C.; Basso, B.; Bertuzzi, P.; Biernath, C.; Boogaard, H.; Boote, K.J.; Brisson, N.; Cammarano, D.; Challinor, A.J.; Conijn, J.G.; Corbeels, M.; Deryng, D.; Sanctis, De G.; Doltra, J.; Gayler, S.; Goldberg, R.; Grassini, P.; Hatfield, J.L.; Heng, L.; Hoek, S.B.; Hooker, J.; Hunt, L.A.; Ingwersen, J.; Izaurralde, C.; Jongschaap, R.E.E.; Jones, J.W.; Kemanian, R.A.; Kersebaum, K.C.; Kim, S.H.; Lizaso, J.; Müller, C.; Naresh Kumar, S.; Nendel, C.; O'Leary, G.J.; Olesen, J.E.; Osborne, T.M.; Palosuo, T.; Pravia, M.V.; Priesack, E.; Ripoche, D.; Rosenzweig, C.; Ruane, A.C.; Sau, F.; Semenov, M.A.; Shcherbak, I.; Steduto, P.; Stöckle, C.O.; Stratonovitch, P.; Streck, T.; Supit, I.; Tao, F.; Teixeira, E.; Thorburn, P.; Timlin, D.; Travasso, M.; Roetter, R.P.; Waha, K.; Wallach, D.; White, J.W.; Williams, J.R.; Wolf, J.

    2015-01-01

    Many simulation studies have been carried out to predict the effect of climate change on crop yield. Typically, in such study, one or several crop models are used to simulate series of crop yield values for different climate scenarios corresponding to different hypotheses of temperature, CO2

  7. Numerical Simulations of Kinetic Alfvén Waves to Study Spectral ...

    Indian Academy of Sciences (India)

    Numerical Simulations of Kinetic Alfvén Waves to Study Spectral. Index in Solar Wind Turbulence and Particle Heating. R. P. Sharma. ∗. & H. D. Singh. Center for Energy Studies, Indian Institute of Technology, Delhi 110 016, India. ∗ e-mail: rpsharma@ces.iitd.ernet.in. Abstract. We present numerical simulations of the ...

  8. Multivariate Meta-Analysis of Genetic Association Studies: A Simulation Study.

    Directory of Open Access Journals (Sweden)

    Binod Neupane

    Full Text Available In a meta-analysis with multiple end points of interests that are correlated between or within studies, multivariate approach to meta-analysis has a potential to produce more precise estimates of effects by exploiting the correlation structure between end points. However, under random-effects assumption the multivariate estimation is more complex (as it involves estimation of more parameters simultaneously than univariate estimation, and sometimes can produce unrealistic parameter estimates. Usefulness of multivariate approach to meta-analysis of the effects of a genetic variant on two or more correlated traits is not well understood in the area of genetic association studies. In such studies, genetic variants are expected to roughly maintain Hardy-Weinberg equilibrium within studies, and also their effects on complex traits are generally very small to modest and could be heterogeneous across studies for genuine reasons. We carried out extensive simulation to explore the comparative performance of multivariate approach with most commonly used univariate inverse-variance weighted approach under random-effects assumption in various realistic meta-analytic scenarios of genetic association studies of correlated end points. We evaluated the performance with respect to relative mean bias percentage, and root mean square error (RMSE of the estimate and coverage probability of corresponding 95% confidence interval of the effect for each end point. Our simulation results suggest that multivariate approach performs similarly or better than univariate method when correlations between end points within or between studies are at least moderate and between-study variation is similar or larger than average within-study variation for meta-analyses of 10 or more genetic studies. Multivariate approach produces estimates with smaller bias and RMSE especially for the end point that has randomly or informatively missing summary data in some individual studies, when

  9. Molecular Simulation Studies of Covalently and Ionically Grafted Nanoparticles

    Science.gov (United States)

    Hong, Bingbing

    Solvent-free covalently- or ionically-grafted nanoparticles (CGNs and IGNs) are a new class of organic-inorganic hybrid composite materials exhibiting fluid-like behaviors around room temperature. With similar structures to prior systems, e.g. nanocomposites, neutral or charged colloids, ionic liquids, etc, CGNs and IGNs inherit the functionality of inorganic nanopariticles, the facile processibility of polymers, as well as conductivity and nonvolatility from their constituent materials. In spite of the extensive prior experimental research having covered synthesis and measurements of thermal and dynamic properties, little progress in understanding of these new materials at the molecular level has been achieved, because of the lack of simulation work in this new area. Atomistic and coarse-grained molecular dynamics simulations have been performed in this thesis to investigate the thermodynamics, structure, and dynamics of these systems and to seek predictive methods predictable for their properties. Starting from poly(ethylene oxide) oligomers (PEO) melts, we established atomistic models based on united-atom representations of methylene. The Green-Kubo and Einstein-Helfand formulas were used to calculate the transport properties. The simulations generate densities, viscosities, diffusivities, in good agreement with experimental data. The chain-length dependence of the transport properties suggests that neither Rouse nor reptation models are applicable in the short-chain regime investigated. Coupled with thermodynamic integration methods, the models give good predictions of pressure-composition-density relations for CO 2 + PEO oligomers. Water effects on the Henry's constant of CO 2 in PEO have also been investigated. The dependence of the calculated Henry's constants on the weight percentage of water falls on a temperature-dependent master curve, irrespective of PEO chain length. CGNs are modeled by the inclusion of solid-sphere nanoparticles into the atomistic

  10. Intensification of transesterification via sonication numerical simulation and sensitivity study

    International Nuclear Information System (INIS)

    Janajreh, Isam; ElSamad, Tala; Noorul Hussain, Mohammed

    2017-01-01

    Highlights: • 3D numerical simulation of transesterification is accomplished. • A non-isothermal, reactive Navier–stokes was carried out. • Conventional and sonicated process was compared as far as reaction kinetics and yield. • Higher kinetic rates are achieved at lower molar ratios in sonicated process. • It validates feasibility of numerical simulation for transesterification assessment. - Abstract: Transesterification is known as slow reaction that can take over several hours to complete. The process involves two immiscible reactants to produce the biodiesel and the byproduct glycerol. Biodiesel commercialization has always been hindered by the long process times of the transesterification reaction. Catalyzing the process and increasing the agitation rate is the mode of intensifying the process additional to the increase of the molar ratio, temperature, circulation that all penalize the overall process metrics. Finding shorter path by reducing the reaction into a few minutes and ensures high quality biodiesel, in economically viable way is coming along with sonication. This drastic reduction moves the technology from the slow batch process into the high throughput continuous process. In a practical sense this means a huge optimization for the biodiesel production process which opens pathways for faster, voluminous and cheaper production. The mechanism of sonication assisted reaction is explained by the creation of microbubbles which increases the interfacial surface reaction areas and the presence of high localized temperature and turbulence as these microbubbles implode. As a result the reaction kinetics of sonicated transesterification as inferred by several authors is much faster. The aim of this work is to implement the inferred rates in a high fidelity numerical reactive flow simulation model while considering the reactor geometry. It is based on Navier–Stokes equations coupled with energy equation for non-isothermal flow and the transport

  11. A computer simulation study of tilted smectic mesophases

    International Nuclear Information System (INIS)

    Withers, I.M.

    2000-05-01

    Results are presented from a series of simulations undertaken to determine the effect of a novel form of molecular biaxiality upon the phase behaviour of the well established Gay-Berne (GB) liquid crystal model. Firstly, the simulation of a bulk system interacting via the Internally-Rotated Gay Berne (IRGB) potential, which offers a single-site representation of a molecule rigidly constrained into a zig-zag conformation, is presented. The results of simulations performed for systems of IRGB particles with an aspect ratio of 3:1 confirm that the introduction of biaxiality into the model results in the destabilisation of the orientationally ordered phases. For particles with a sufficiently pronounced zig-zag conformation, this results in the complete destabilisation of the smectic A phase and the smectic B phase being replaced by the tilted smectic J phase. Following these observations, the effect upon the phase behaviour of increasing molecular elongation is also considered, with an increase in the aspect ratio from 3:1 to 4:1 resulting in the nematic and smectic J phases being replaced by smectic A and smectic G phases respectively. Secondly, a version of the IRGB potential modified to include a degree of molecular flexibility is considered. Results obtained from bulk systems interacting via the flexible IRGB for 3:1 and 4:1 molecules show that the introduction of flexibility results in the destabilisation of the smectic A phase and the stabilisation of the nematic and tilted hexatic phases. Finally, the effect upon the phase behaviour of the rigid IRGB model of the inclusion of a longitudinal linear quadrupole is examined. These results show that increasing quadrupole moment results in the destabilisation of the tilted hexatic phase, although the biaxial order parameter is increased with increasing quadrupole moment. There is no clear correlation between quadrupole magnitude and the other observed phase transitions, with the nematic and smectic A phases being

  12. Statistical methods for elimination of guarantee-time bias in cohort studies: a simulation study

    Directory of Open Access Journals (Sweden)

    In Sung Cho

    2017-08-01

    Full Text Available Abstract Background Aspirin has been considered to be beneficial in preventing cardiovascular diseases and cancer. Several pharmaco-epidemiology cohort studies have shown protective effects of aspirin on diseases using various statistical methods, with the Cox regression model being the most commonly used approach. However, there are some inherent limitations to the conventional Cox regression approach such as guarantee-time bias, resulting in an overestimation of the drug effect. To overcome such limitations, alternative approaches, such as the time-dependent Cox model and landmark methods have been proposed. This study aimed to compare the performance of three methods: Cox regression, time-dependent Cox model and landmark method with different landmark times in order to address the problem of guarantee-time bias. Methods Through statistical modeling and simulation studies, the performance of the above three methods were assessed in terms of type I error, bias, power, and mean squared error (MSE. In addition, the three statistical approaches were applied to a real data example from the Korean National Health Insurance Database. Effect of cumulative rosiglitazone dose on the risk of hepatocellular carcinoma was used as an example for illustration. Results In the simulated data, time-dependent Cox regression outperformed the landmark method in terms of bias and mean squared error but the type I error rates were similar. The results from real-data example showed the same patterns as the simulation findings. Conclusions While both time-dependent Cox regression model and landmark analysis are useful in resolving the problem of guarantee-time bias, time-dependent Cox regression is the most appropriate method for analyzing cumulative dose effects in pharmaco-epidemiological studies.

  13. Multi-Bunch Simulations of the ILC for Luminosity Performance Studies

    CERN Document Server

    White, Glen; Walker, Nicholas J

    2005-01-01

    To study the luminosity performance of the International Linear Collider (ILC) with different design parameters, a simulation was constructed that tracks a multi-bunch representation of the beam from the Damping Ring extraction through to the Interaction Point. The simulation code PLACET is used to simulate the LINAC, MatMerlin is used to track through the Beam Delivery System and GUINEA-PIG for the beam-beam interaction. Included in the simulation are ground motion and wakefield effects, intra-train fast feedback and luminosity-based feedback systems. To efficiently study multiple parameters/multiple seeds, the simulation is deployed on the Queen Mary High-Throughput computing cluster at Queen Mary, University of London, where 100 simultaneous simulation seeds can be run.

  14. Shuttle/TDRSS modelling and link simulation study

    Science.gov (United States)

    Braun, W. R.; Mckenzie, T. M.; Biederman, L.; Lindsey, W. C.

    1979-01-01

    A Shuttle/TDRSS S-band and Ku-band link simulation package called LinCsim was developed for the evaluation of link performance for specific Shuttle signal designs. The link models were described in detail and the transmitter distortion parameters or user constraints were carefully defined. The overall link degradation (excluding hardware degradations) relative to an ideal BPSK channel were given for various sets of user constraint values. The performance sensitivity to each individual user constraint was then illustrated. The effect of excessive Spacelab clock jitter on the return link BER performance was also investigated as was the problem of subcarrier recovery for the K-band Shuttle return link signal.

  15. Fokker-Planck simulation study of Alfven eigenmode burst

    International Nuclear Information System (INIS)

    Todo, Y.; Watanabe, T.; Park, Hyoung-Bin; Sato, T.

    2001-01-01

    Recurrent bursts of toroidicity-induced Alfven eigenmodes (TAEs) are reproduced with a Fokker-Planck-magnetohydrodynamic simulation where a fast-ion source and slowing down are incorporated self-consistently. The bursts take place at regular time intervals and the behaviors of all the TAEs are synchronized. The fast-ion transport due to TAE activity spatially broadens the classical fast-ion distribution and significantly reduces its peak value. Only a small change of the distribution takes place with each burst, leading to loss of a small fraction of the fast ions. The system stays close to the marginal stability state established through the interplay of the fast-ion source, slowing down, and TAE activity. (author)

  16. Hybrid Computational Simulation and Study of Terahertz Pulsed Photoconductive Antennas

    Science.gov (United States)

    Emadi, R.; Barani, N.; Safian, R.; Nezhad, A. Zeidaabadi

    2016-11-01

    A photoconductive antenna (PCA) has been numerically investigated in the terahertz (THz) frequency band based on a hybrid simulation method. This hybrid method utilizes an optoelectronic solver, Silvaco TCAD, and a full-wave electromagnetic solver, CST. The optoelectronic solver is used to find the accurate THz photocurrent by considering realistic material parameters. Performance of photoconductive antennas and temporal behavior of the excited photocurrent for various active region geometries such as bare-gap electrode, interdigitated electrodes, and tip-to-tip rectangular electrodes are investigated. Moreover, investigations have been done on the center of the laser illumination on the substrate, substrate carrier lifetime, and diffusion photocurrent associated with the carriers temperature, to achieve efficient and accurate photocurrent. Finally, using the full-wave electromagnetic solver and the calculated photocurrent obtained from the optoelectronic solver, electromagnetic radiation of the antenna and its associated detected THz signal are calculated and compared with a measurement reference for verification.

  17. Simulation and experiemntal study on damper by accumulator

    International Nuclear Information System (INIS)

    Wang Xiaobin; Zhou Yong; Chen Wuxing; Hu Junhua

    2010-01-01

    In order to prevent stressing penstocks broken by earthquake or other shock waves, dampers are used widely in nuclear power plant or pipelines transporting radioactive material. A new-style damper by accumulator is introduced. Inside the damper an accumulator is installed, the outward corrugated tubes are added outside the piston rod. So it has advantages of small volume, no oil leakage. The simulation and experimental research show that if the clearance between the piston and cylinder, the spring stiffness of accumulator or the throttle valve size is varied, the dynamic performance of the impact displacement, resistance in low velocity and lock-up velocity of dampe would be influenced. The support of nuclear classified pipelines can be satisfied by using this new-style accumulator damper. (authors)

  18. Design and Study of Cognitive Network Physical Layer Simulation Platform

    Directory of Open Access Journals (Sweden)

    Yongli An

    2014-01-01

    Full Text Available Cognitive radio technology has received wide attention for its ability to sense and use idle frequency. IEEE 802.22 WRAN, the first to follow the standard in cognitive radio technology, is featured by spectrum sensing and wireless data transmission. As far as wireless transmission is concerned, the availability and implementation of a mature and robust physical layer algorithm are essential to high performance. For the physical layer of WRAN using OFDMA technology, this paper proposes a synchronization algorithm and at the same time provides a public platform for the improvement and verification of that new algorithm. The simulation results show that the performance of the platform is highly close to the theoretical value.

  19. Updated Simulation Studies of Damage Limit of LHC Tertiary Collimators

    CERN Document Server

    AUTHOR|(CDS)2085459; Bertarelli, Alessandro; Bruce, Roderik; Carra, Federico; Cerutti, Francesco; Gradassi, Paolo; Lechner, Anton; Redaelli, Stefano; Skordis, Eleftherios

    2015-01-01

    The tertiary collimators (TCTs) in the LHC, installed in front of the experiments, in standard operation intercept fractions of 10−3 halo particles. However, they risk to be hit by high-intensity primary beams in case of asynchronous beam dump. TCT damage thresholds were initially inferred from results of destructive tests on a TCT jaw, supported by numerical simulations, assuming simplified impact scenarios with one single bunch hitting the jaw with a given impact parameter. In this paper, more realistic failure conditions, including a train of bunches and taking into account the full collimation hierarchy, are used to derive updated damage limits. The results are used to update the margins in the collimation hierarchy and could thus potentially have an influence on the LHC performance.

  20. Simulation studies of a wide area health care network.

    Science.gov (United States)

    McDaniel, J. G.

    1994-01-01

    There is an increasing number of efforts to install wide area health care networks. Some of these networks are being built to support several applications over a wide user base consisting primarily of medical practices, hospitals, pharmacies, medical laboratories, payors, and suppliers. Although on-line, multi-media telecommunication is desirable for some purposes such as cardiac monitoring, store-and-forward messaging is adequate for many common, high-volume applications. Laboratory test results and payment claims, for example, can be distributed using electronic messaging networks. Several network prototypes have been constructed to determine the technical problems and to assess the effectiveness of electronic messaging in wide area health care networks. Our project, Health Link, developed prototype software that was able to use the public switched telephone network to exchange messages automatically, reliably and securely. The network could be configured to accommodate the many different traffic patterns and cost constraints of its users. Discrete event simulations were performed on several network models. Canonical star and mesh networks, that were composed of nodes operating at steady state under equal loads, were modeled. Both topologies were found to support the throughput of a generic wide area health care network. The mean message delivery time of the mesh network was found to be less than that of the star network. Further simulations were conducted for a realistic large-scale health care network consisting of 1,553 doctors, 26 hospitals, four medical labs, one provincial lab and one insurer. Two network topologies were investigated: one using predominantly peer-to-peer communication, the other using client-server communication.(ABSTRACT TRUNCATED AT 250 WORDS) PMID:7949966

  1. Experimental study on foam coverage on simulated longwall roof

    Science.gov (United States)

    Reed, W.R.; Zheng, Y.; Klima, S.; Shahan, M.R.; Beck, T.W.

    2018-01-01

    Testing was conducted to determine the ability of foam to maintain roof coverage in a simulated longwall mining environment. Approximately 27 percent of respirable coal mine dust can be attributed to longwall shield movement, and developing controls for this dust source has been difficult. The application of foam is a possible dust control method for this source. Laboratory testing of two foam agents was conducted to determine the ability of the foam to adhere to a simulated longwall face roof surface. Two different foam generation methods were used: compressed air and blower air. Using a new imaging technology, image processing and analysis utilizing ImageJ software produced quantifiable results of foam roof coverage. For compressed air foam in 3.3 m/s (650 fpm) ventilation, 98 percent of agent A was intact while 95 percent of agent B was intact on the roof at three minutes after application. At 30 minutes after application, 94 percent of agent A was intact while only 20 percent of agent B remained. For blower air in 3.3 m/s (650 fpm) ventilation, the results were dependent upon nozzle type. Three different nozzles were tested. At 30 min after application, 74 to 92 percent of foam agent A remained, while 3 to 50 percent of foam agent B remained. Compressed air foam seems to remain intact for longer durations and is easier to apply than blower air foam. However, more water drained from the foam when using compressed air foam, which demonstrates that blower air foam retains more water at the roof surface. Agent A seemed to be the better performer as far as roof application is concerned. This testing demonstrates that roof application of foam is feasible and is able to withstand a typical face ventilation velocity, establishing this technique’s potential for longwall shield dust control. PMID:29563765

  2. Solar energetic particles: observational studies and magnetohydrodynamic simulation

    International Nuclear Information System (INIS)

    Masson, S.

    2010-10-01

    Solar activity manifests itself through highly dynamical events, such as flares and coronal mass ejections, which result in energy release by magnetic reconnection. This thesis focuses on two manifestations of this energy release: solar energetic particles and dynamics of magnetic reconnection. The first part of my work consists in the detailed temporal analysis of several electromagnetic signatures, produced by energetic particles in the solar atmosphere, with respect to the energetic particle flux at Earth. Using multi-instrument observations, I highlighted that particles can be accelerated by the flare to relativistic energies during a specific episode of acceleration in the impulsive phase. This showed that particles traveled a longer path length than the theoretical length generally assumed. Using in-situ measurements of magnetic field and plasma, I identified the interplanetary magnetic field for 10 particle events, and performing a velocity dispersion analysis I obtained the interplanetary length traveled by particles. I showed that the magnetic structure of the interplanetary medium play a crucial role in the association of the particle flux at Earth and the acceleration signatures of particles at the Sun. The second part of my work focuses on the dynamics of magnetic reconnection. Observationally, the best evidence for magnetic reconnection is the appearance of brightnesses at the solar surface. Performing the first data-driven 3 dimensional magneto-hydrodynamic (MHD) simulation of an observed event, I discovered that the evolution of brightnesses can be explained by the succession of two different reconnection regimes, induced by a new topological association where null-point separatrix lines are embedded in quasi-separatrix layers. This new topological association induces a change of field line connectivity, but also a continuous reconnection process, leading to an apparent slipping motion of reconnected field lines. From a MHD simulation I showed that

  3. Genetic Simulation Tools for Post-Genome Wide Association Studies of Complex Diseases

    Science.gov (United States)

    Amos, Christopher I.; Bafna, Vineet; Hauser, Elizabeth R.; Hernandez, Ryan D.; Li, Chun; Liberles, David A.; McAllister, Kimberly; Moore, Jason H.; Paltoo, Dina N.; Papanicolaou, George J.; Peng, Bo; Ritchie, Marylyn D.; Rosenfeld, Gabriel; Witte, John S.

    2014-01-01

    Genetic simulation programs are used to model data under specified assumptions to facilitate the understanding and study of complex genetic systems. Standardized data sets generated using genetic simulation are essential for the development and application of novel analytical tools in genetic epidemiology studies. With continuing advances in high-throughput genomic technologies and generation and analysis of larger, more complex data sets, there is a need for updating current approaches in genetic simulation modeling. To provide a forum to address current and emerging challenges in this area, the National Cancer Institute (NCI) sponsored a workshop, entitled “Genetic Simulation Tools for Post-Genome Wide Association Studies of Complex Diseases” at the National Institutes of Health (NIH) in Bethesda, Maryland on March 11-12, 2014. The goals of the workshop were to: (i) identify opportunities, challenges and resource needs for the development and application of genetic simulation models; (ii) improve the integration of tools for modeling and analysis of simulated data; and (iii) foster collaborations to facilitate development and applications of genetic simulation. During the course of the meeting the group identified challenges and opportunities for the science of simulation, software and methods development, and collaboration. This paper summarizes key discussions at the meeting, and highlights important challenges and opportunities to advance the field of genetic simulation. PMID:25371374

  4. A study of the use of simulated work task situations in interactive information retrieval evaluations

    DEFF Research Database (Denmark)

    Borlund, Pia

    2016-01-01

    Purpose – The purpose of this paper is to report a study of how the test instrument of a simulated work task situation is used in empirical evaluations of interactive information retrieval (IIR) and reported in the research literature. In particular, the author is interested to learn whether....... The paper addresses the need to carefully design and tailor simulated work task situations to suit the test participants in order to obtain the intended authentic and realistic IIR under study. Keywords Interactive information retrieval study, IIR study, Test design, Simulated work task situations, Meta-evaluation...... situations in IIR evaluations. In particular, with respect to the design and creation of realistic simulated work task situations. There is a lack of tailoring of the simulated work task situations to the test participants. Likewise, the requirement to include the test participants’ personal information...

  5. Realization of a Desktop Flight Simulation System for Motion-Cueing Studies

    Directory of Open Access Journals (Sweden)

    Berkay Volkaner

    2016-05-01

    Full Text Available Parallel robotic mechanisms are generally used in flight simulators with a motion-cueing algorithm to create an unlimited motion feeling of a simulated medium in a bounded workspace of the simulator. A major problem in flight simulators is that the simulation has an unbounded space and the manipulator has a limited one. Using a washout filter in the motion-cueing algorithm overcomes this. In this study, a low-cost six degrees of freedom (DoF desktop parallel manipulator is used to test a classical motion-cueing algorithm; the algorithm's functionality is confirmed with a Simulink real-time environment. Translational accelerations and angular velocities of the simulated medium obtained from FlightGear flight simulation software are processed through a generated washout filter algorithm and the simulated medium's motion information is transmitted to the desktop parallel robotic mechanism as a set point for each leg. The major issues of this paper are designing a desktop simulation system, controlling the parallel manipulator, communicating between the flight simulation and the platform, designing a motion-cueing algorithm and determining the parameters of the washout filters.

  6. Experimental study on treatment of simulated boron containing radioactive wastewater by reverse osmosis membrane

    International Nuclear Information System (INIS)

    Wang Xiaowei; Yang Kai; Kong Jinsong

    2012-01-01

    Experiments were carried out on a pilot equipment to study the performance of treatment of simulated boron containing radioactive wastewater by reverse osmosis membrane. Results showed that the rejection efficiency of boron, simulated nuclides and salts in simulated wastewater could be enhanced by increasing the feedwater pH, improving the applied pressure or reducing the recovery ratio. By adjusting the simulated wastewater pH to 9.0, the boron concentration in permeate could be lower than 5 mg/L and two nuclides including cobalt and cesium could be removed to a satisfied extend. (authors)

  7. Analysis of nanowire transistor based nitrogen dioxide gas sensor – A simulation study

    Directory of Open Access Journals (Sweden)

    Gaurav Saxena

    2015-06-01

    Full Text Available Sensors sensitivity, selectivity and stability has always been a prime design concern for gas sensors designers. Modeling and simulation of gas sensors aids the designers in improving their performance. In this paper, different routes for the modeling and simulation of a semiconducting gas sensor is presented. Subsequently, by employing one of the route, the response of Zinc Oxide nanowire transistor towards nitrogen dioxide ambient is simulated. In addition to the sensing mechanism, simulation study of gas species desorption by applying a recovery voltage is also presented.

  8. Simulation study of stepwise relaxation in a spheromak plasma

    International Nuclear Information System (INIS)

    Horiuchi, Ritoku; Uchida, Masaya; Sato, Tetsuya.

    1991-10-01

    The energy relaxation process of a spheromak plasma in a flux conserver is investigated by means of a three-dimensional magnetohydrodynamic simulation. The resistive decay of an initial force-free profile brings the spheromak plasma to an m = 1/n = 2 ideal kink unstable region. It is found that the energy relaxation takes place in two steps; namely, the relaxation consists of two physically distinguished phases, and there exists an intermediate phase in between, during which the relaxation becomes inactive temporarily. The first relaxation corresponds to the transition from an axially symmetric force-free state to a helically symmetric one with an n = 2 crescent magnetic island structure via the helical kink instability. The n = 2 helical structure is nonlinearly sustained in the intermediate phase. The helical twisting of the flux tube creates a reconnection current in the vicinity of the geometrical axis. The second relaxation is triggered by the rapid growth of the n = 1 mode when the reconnection current exceeds a critical value. The helical twisting relaxes through magnetic reconnection toward an axially symmetric force-free state. It is also found that the poloidal flux reduces during the helical twisting in the first relaxation and the generation of the toroidal flux occurs through the magnetic reconnection process in the second relaxation. (author)

  9. Simulation Study of Swarm Intelligence Based on Life Evolution Behavior

    Directory of Open Access Journals (Sweden)

    Yanmin Liu

    2015-01-01

    Full Text Available Swarm intelligence (SI is a new evolutionary computation technology, and its performance efficacy is usually affected by each individual behavior in the swarm. According to the genetic and sociological theory, the life evolution behavior process is influenced by the external and internal factors, so the mechanisms of external and internal environment change must be analyzed and explored. Therefore, in this paper, we used the thought of the famous American genetic biologist Morgan, “life = DNA + environment + interaction of environment + gene,” to propose the mutation and crossover operation of DNA fragments by the environmental change to improve the performance efficiency of intelligence algorithms. Additionally, PSO is a random swarm intelligence algorithm with the genetic and sociological property, so we embed the improved mutation and crossover operation to particle swarm optimization (PSO and designed DNA-PSO algorithm to optimize single and multiobjective optimization problems. Simulation experiments in single and multiobjective optimization problems show that the proposed strategies can effectively improve the performance of swarm intelligence.

  10. Asymmetric switching in a homodimeric ABC transporter: a simulation study.

    Directory of Open Access Journals (Sweden)

    Jussi Aittoniemi

    2010-04-01

    Full Text Available ABC transporters are a large family of membrane proteins involved in a variety of cellular processes, including multidrug and tumor resistance and ion channel regulation. Advances in the structural and functional understanding of ABC transporters have revealed that hydrolysis at the two canonical nucleotide-binding sites (NBSs is co-operative and non-simultaneous. A conserved core architecture of bacterial and eukaryotic ABC exporters has been established, as exemplified by the crystal structure of the homodimeric multidrug exporter Sav1866. Currently, it is unclear how sequential ATP hydrolysis arises in a symmetric homodimeric transporter, since it implies at least transient asymmetry at the NBSs. We show by molecular dynamics simulation that the initially symmetric structure of Sav1866 readily undergoes asymmetric transitions at its NBSs in a pre-hydrolytic nucleotide configuration. MgATP-binding residues and a network of charged residues at the dimer interface are shown to form a sequence of putative molecular switches that allow ATP hydrolysis only at one NBS. We extend our findings to eukaryotic ABC exporters which often consist of two non-identical half-transporters, frequently with degeneracy substitutions at one of their two NBSs. Interestingly, many residues involved in asymmetric conformational switching in Sav1866 are substituted in degenerate eukaryotic NBS. This finding strengthens recent suggestions that the interplay of a consensus and a degenerate NBS in eukaroytic ABC proteins pre-determines the sequence of hydrolysis at the two NBSs.

  11. Fundus oculi pigmentation studies simulating the fs-LASIK process

    Energy Technology Data Exchange (ETDEWEB)

    Sander, M; Tetz, M R [Berlin Eye Research Institute, Alt Moabit 101b, 10559 Berlin (Germany); Minet, O; Zabarylo, U [Charite Centrum 6, Arbeitsgruppe Medizinische Physik/Optische Diagnostik, Fabeckstrasse 60–62, 14195 Berlin (Germany); Mueller, M [Augenklinik Ahaus, Am Schlossgraben 13, 48683 Ahaus (Germany)

    2012-06-15

    The femtosecond-laser in situ keratomileusis (fs-LASIK) technique has successfully entered the refractive surgery market to correct ametropia by cutting transparent corneal tissue with ultra-short laser pulses based on photodisruption. The laser pulses in the near infrared range (NIR) generate a laser-induced breakdown (LIOB) in the cornea. By propagating through the eye, a certain amount of the pulse is deposited in the cornea and the remaining energy interacts with the strong absorbing tissue behind. Due to the absorption by the retinal pigment epithelium and the transfer of the thermal energy to surrounding tissue, the transmitted energy can induce damage to the retina. The aim of this project was to find out the threshold influences concerning the tissue and the correlation between the results of the macroscopical appraisal and the fundus oculi pigmentation by simulating the fs-LASIK procedure with two various laser systems in the continuous wave (CW) and fs-regime. Therefore ex-vivo determinations were carried out macroscopically and histopathologically on porcine tissue.

  12. Fundus oculi pigmentation studies simulating the fs-LASIK process

    International Nuclear Information System (INIS)

    Sander, M; Tetz, M R; Minet, O; Zabarylo, U; Mueller, M

    2012-01-01

    The femtosecond-laser in situ keratomileusis (fs-LASIK) technique has successfully entered the refractive surgery market to correct ametropia by cutting transparent corneal tissue with ultra-short laser pulses based on photodisruption. The laser pulses in the near infrared range (NIR) generate a laser-induced breakdown (LIOB) in the cornea. By propagating through the eye, a certain amount of the pulse is deposited in the cornea and the remaining energy interacts with the strong absorbing tissue behind. Due to the absorption by the retinal pigment epithelium and the transfer of the thermal energy to surrounding tissue, the transmitted energy can induce damage to the retina. The aim of this project was to find out the threshold influences concerning the tissue and the correlation between the results of the macroscopical appraisal and the fundus oculi pigmentation by simulating the fs-LASIK procedure with two various laser systems in the continuous wave (CW) and fs-regime. Therefore ex-vivo determinations were carried out macroscopically and histopathologically on porcine tissue

  13. A simulator-based study of in-flight auscultation.

    Science.gov (United States)

    Tourtier, Jean-Pierre; Libert, Nicolas; Clapson, Patrick; Dubourdieu, Stéphane; Jost, Daniel; Tazarourte, Karim; Astaud, Cécil-Emmanuel; Debien, Bruno; Auroy, Yves

    2014-04-01

    The use of a stethoscope is essential to the delivery of continuous, supportive en route care during aeromedical evacuations. We compared the capability of 2 stethoscopes (electronic, Litmann 3000; conventional, Litmann Cardiology III) at detecting pathologic heart and lung sounds, aboard a C135, a medical transport aircraft. Sounds were mimicked using a mannequin-based simulator SimMan. Five practitioners examined the mannequin during a fly, with a variety of abnormalities as follows: crackles, wheezing, right and left lung silence, as well as systolic, diastolic, and Austin-Flint murmur. The comparison for diagnosis assessed (correct or wrong) between using the electronic and conventional stethoscopes were performed as a McNemar test. A total of 70 evaluations were performed. For cardiac sounds, diagnosis was right in 0/15 and 4/15 auscultations, respectively, with conventional and electronic stethoscopes (McNemar test, P = 0.13). For lung sounds, right diagnosis was found with conventional stethoscope in 10/20 auscultations versus 18/20 with electronic stethoscope (P = 0.013). Flight practitioners involved in aeromedical evacuation on C135 plane are more able to practice lung auscultation on a mannequin with this amplified stethoscope than with the traditional one. No benefit was found for heart sounds.

  14. Three dimensional simulation study of spheromak injection into magnetized plasmas

    International Nuclear Information System (INIS)

    Suzuki, Y.; Watanabe, T.H.; Sato, T.; Hayashi, T.

    2000-01-01

    The three dimensional dynamics of a spheromak-like compact toroid (SCT) plasmoid, which is injected into a magnetized target plasma region, is investigated by using MHD numerical simulations. It is found that the process of SCT penetration into this region is much more complicated than that which has been analysed so far by using a conducting sphere (CS) model. The injected SCT suffers from a tilting instability, which grows with a similar timescale to that of the SCT penetration. The instability is accompanied by magnetic reconnection between the SCT magnetic field and the target magnetic field, which disrupts the magnetic configuration of the SCT. Magnetic reconnection plays a role in supplying the high density plasma, initially confined in the SCT magnetic field, to the target region. The penetration depth of the SCT high density plasma is also examined. It is shown to be shorter than that estimated from the CS model. The SCT high density plasma is decelerated mainly by the Lorentz force of the target magnetic field, which includes not only the magnetic pressure force but also the magnetic tension force. Furthermore, by comparing the SCT plasmoid injection with the bare plasmoid injection, magnetic reconnection is considered to relax the magnetic tension force, i.e. the deceleration of the SCT plasmoid. (author)

  15. Simulation and experimental study on lithium ion battery short circuit

    International Nuclear Information System (INIS)

    Zhao, Rui; Liu, Jie; Gu, Junjie

    2016-01-01

    Highlights: • Both external and internal short circuit tests were performed on Li-ion batteries. • An electrochemical–thermal model with an additional nail site heat source is presented. • The model can accurately simulate the temperature variations of non-venting batteries. • The model is reliable in predicting the occurrence and start time of thermal runaway. • A hydrogel cooling system proves its strength in preventing battery thermal runaway. - Abstract: Safety is the first priority in lithium ion (Li-ion) battery applications. A large portion of electrical and thermal hazards caused by Li-ion battery is associated with short circuit. In this paper, both external and internal short circuit tests are conducted. Li-ion batteries and battery packs of different capacities are used. The results indicate that external short circuit is worse for smaller size batteries due to their higher internal resistances, and this type of short can be well managed by assembling fuses. In internal short circuit tests, higher chance of failure is found on larger capacity batteries. A modified electrochemical–thermal model is proposed, which incorporates an additional heat source from nail site and proves to be successful in depicting temperature changes in batteries. Specifically, the model is able to estimate the occurrence and approximate start time of thermal runaway. Furthermore, the effectiveness of a hydrogel based thermal management system in suppressing thermal abuse and preventing thermal runaway propagation is verified through the external and internal short tests on batteries and battery packs.

  16. Learning Support Assessment Study of a Computer Simulation for the Development of Microbial Identification Strategies

    Directory of Open Access Journals (Sweden)

    Tristan E. Johnson

    2009-12-01

    Full Text Available This paper describes a study that examined how microbiology students construct knowledge of bacterial identification while using a computer simulation. The purpose of this study was to understand how the simulation affects the cognitive processing of students during thinking, problem solving, and learning about bacterial identification and to determine how the simulation facilitates the learning of a domain-specific problem-solving strategy. As part of an upper-division microbiology course, five students participated in several simulation assignments. The data were collected using think-aloud protocol and video action logs as the students used the simulation. The analysis revealed two major themes that determined the performance of the students: Simulation Usage—how the students used the software features and Problem-Solving Strategy Development—the strategy level students started with and the skill level they achieved when they completed their use of the simulation. Several conclusions emerged from the analysis of the data: (i The simulation affects various aspects of cognitive processing by creating an environment that makes it possible to practice the application of a problem-solving strategy. The simulation was used as an environment that allowed students to practice the cognitive skills required to solve an unknown. (ii Identibacter (the computer simulation may be considered to be a cognitive tool to facilitate the learning of a bacterial identification problem-solving strategy. (iii The simulation characteristics did support student learning of a problem-solving strategy. (iv Students demonstrated problem-solving strategy development specific to bacterial identification. (v Participants demonstrated an improved performance from their repeated use of the simulation.

  17. Development of a simulation platform for dynamic simulation and control studies of AP1000 nuclear steam supply system

    International Nuclear Information System (INIS)

    Wan, Jiashuang; Song, Hongbing; Yan, Shoujun; Sun, Jian; Zhao, Fuyu

    2015-01-01

    Highlights: • A fast-running simulation platform named NCAP was developed on a personal computer using MATLAB/Simulink. • Three types of typical operations, namely 10% step load change, 5%/min ramp load change and load follow were simulated. • NCAP predictions were compared with those obtained by CENTS for the load regulation transients. - Abstract: This paper presents the development, application and performance assessment of a fast-running NCAP (NSSS Control & Analysis Platform) in MATLAB/Simulink environment. First, a nodal core model, a lumped parameter dynamic steam generator model with moving boundary, a non-equilibrium two-regions-three-volumes pressurizer model, and the relevant pipe and plenum models were proposed based on the fundamental conservation of mass, energy and momentum. Then, these first order nonlinear models and the NSSS control systems were implemented in the Simulink by the predefined library blocks. Based on the developed NCAP, three types of typical operational transients, namely the 10% step load change, the 5%/min ramp load change and the daily load follow were simulated to study the dynamic behavior and control characteristics of the AP1000 NSSS. It has been demonstrated that the dynamic responses of the selected key parameters agree well with the general physical rules. In addition, the comparison of load regulation simulation results obtained by NCAP and CENTS shows a good agreement in terms of the changing trends. With the adoption of modular programming techniques, the NCAP facilitates easy modification and runs quickly, which easily allows the control system designer to test and compare various ideas efficiently

  18. Molecular Simulation Study of Montmorillonite in Contact with Variably Wet Supercritical Carbon Dioxide

    KAUST Repository

    Kadoura, Ahmad Salim; Nair, Arun Kumar Narayanan; Sun, Shuyu

    2017-01-01

    We perform grand canonical Monte Carlo simulations to study the detailed molecular mechanism of intercalation behavior of CO2 in Na-, Ca-, and Mg- montmorillonite exposed to variably hydrated supercritical CO2 at 323.15 K and 90 bar, The simulations

  19. The Impact of Learner's Prior Knowledge on Their Use of Chemistry Computer Simulations: A Case Study

    Science.gov (United States)

    Liu, Han-Chin; Andre, Thomas; Greenbowe, Thomas

    2008-01-01

    It is complicated to design a computer simulation that adapts to students with different characteristics. This study documented cases that show how college students' prior chemistry knowledge level affected their interaction with peers and their approach to solving problems with the use of computer simulations that were designed to learn…

  20. Corrosion Inhibition Study of Al-Cu-Ni Alloy in Simulated Sea-Water ...

    African Journals Online (AJOL)

    Akorede

    ABSTRACT: A study on the inhibition of Al-Cu-Ni alloy in simulated ... which the percentage of Copper, and Nickel were kept .... proceed based on equation of reaction in eqn (4). Al .... Sodium-Modified A356.0-Type Al-Si-Mg Alloy in Simulated.

  1. Use of a Metronome in Cardiopulmonary Resuscitation: A Simulation Study.

    Science.gov (United States)

    Zimmerman, Elise; Cohen, Naiomi; Maniaci, Vincenzo; Pena, Barbara; Lozano, Juan Manuel; Linares, Marc

    2015-11-01

    Determine whether the use of a metronome improves chest compression rate and depth during cardiopulmonary resuscitation (CPR) on a pediatric manikin. A prospective, simulation-based, crossover, randomized controlled trial was conducted. Participants included pediatric residents, fellows, nurses, and medical students who were randomly assigned to perform chest compressions on a pediatric manikin with and without an audible metronome. Each participant performed 2 rounds of 2 minutes of chest compressions separated by a 15-minute break. A total of 155 participants performed 2 rounds of chest compressions (74 with the metronome on during the first round and 81 with the metronome on during the second round of CPR). There was a significant improvement in the mean percentage of compressions delivered within an adequate rate (90-100 compressions per minute) with the metronome on compared with off (72% vs 50%; mean difference [MD] 22%; 95% confidence interval [CI], 15% to 29%). No significant difference was noted in the mean percentage of compressions within acceptable depth (38-51 mm) (72% vs 70%; MD 2%; 95% CI, -2% to 6%). The metronome had a larger effect among medical students (73% vs 55%; MD 18%; 95% CI, 8% to 28%) and pediatric residents and fellows (84% vs 48%; MD 37%; 95% CI, 27% to 46%) but not among pediatric nurses (46% vs 48%; MD -3%; 95% CI, -19% to 14%). The rate of chest compressions during CPR can be optimized by the use of a metronome. These findings will help medical professionals comply with the American Heart Association guidelines. Copyright © 2015 by the American Academy of Pediatrics.

  2. New media simulation stories in nursing education: a quasi-experimental study exploring learning outcomes.

    Science.gov (United States)

    Webb-Corbett, Robin; Schwartz, Melissa Renee; Green, Bob; Sessoms, Andrea; Swanson, Melvin

    2013-04-01

    New media simulation stories are short multimedia presentations that combine simulation, digital technology, and story branching to depict a variety of healthcare-related scenarios. The purpose of this study was to explore whether learning outcomes were enhanced if students viewed the results of both correct and incorrect nursing actions demonstrated through new media simulation stories. A convenience sample of 109 undergraduate nursing students in a family-centered maternity course participated in the study. Study findings suggests that students who viewed both correct and incorrect depictions of maternity nursing actions scored better on tests than did those students who viewed only correct nursing actions.

  3. Wire chamber requirements and tracking simulation studies for tracking systems at the superconducting super collider

    International Nuclear Information System (INIS)

    Hanson, G.G.; Niczyporuk, B.B.; Palounek, A.P.T.

    1989-02-01

    Limitations placed on wire chambers by radiation damage and rate requirements in the SSC environment are reviewed. Possible conceptual designs for wire chamber tracking systems which meet these requirements are discussed. Computer simulation studies of tracking in such systems are presented. Simulations of events from interesting physics at the SSC, including hits from minimum bias background events, are examined. Results of some preliminary pattern recognition studies are given. Such computer simulation studies are necessary to determine the feasibility of wire chamber tracking systems for complex events in a high-rate environment such as the SSC. 11 refs., 9 figs., 1 tab

  4. Experiment-scale molecular simulation study of liquid crystal thin films

    Science.gov (United States)

    Nguyen, Trung Dac; Carrillo, Jan-Michael Y.; Matheson, Michael A.; Brown, W. Michael

    2014-03-01

    Supercomputers have now reached a performance level adequate for studying thin films with molecular detail at the relevant scales. By exploiting the power of GPU accelerators on Titan, we have been able to perform simulations of characteristic liquid crystal films that provide remarkable qualitative agreement with experimental images. We have demonstrated that key features of spinodal instability can only be observed with sufficiently large system sizes, which were not accessible with previous simulation studies. Our study emphasizes the capability and significance of petascale simulations in providing molecular-level insights in thin film systems as well as other interfacial phenomena.

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

    Science.gov (United States)

    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.

  6. Fundus oculi pigmentation studies simulating the fs-LASIK process Fundus oculi pigmentation studies simulating the fs-LASIK process

    Science.gov (United States)

    Sander, M.; Minet, O.; Zabarylo, U.; Müller, M.; Tetz, M. R.

    2012-06-01

    The femtosecond-laser in situ keratomileusis (fs-LASIK) technique has successfully entered the refractive surgery market to correct ametropia by cutting transparent corneal tissue with ultra-short laser pulses based on photodisruption. The laser pulses in the near infrared range (NIR) generate a laser-induced breakdown (LIOB) in the cornea. By propagating through the eye, a certain amount of the pulse is deposited in the cornea and the remaining energy interacts with the strong absorbing tissue behind. Due to the absorption by the retinal pigment epithelium and the transfer of the thermal energy to surrounding tissue, the transmitted energy can induce damage to the retina. The aim of this project was to find out the threshold influences concerning the tissue and the correlation between the results of the macroscopical appraisal and the fundus oculi pigmentation by simulating the fs-LASIK procedure with two various laser systems in the continuous wave (CW) and fs-regime. Therefore ex-vivo determinations were carried out macroscopically and histopathologically on porcine tissue.

  7. COMPARATIVE STUDY OF TERTIARY WASTEWATER TREATMENT BY COMPUTER SIMULATION

    OpenAIRE

    Stefania Iordache; Nicolae Petrescu; Cornel Ianache

    2010-01-01

    The aim of this work is to asses conditions for implementation of a Biological Nutrient Removal (BNR) process in theWastewater Treatment Plant (WWTP) of Moreni city (Romania). In order to meet the more increased environmentalregulations, the wastewater treatment plant that was studied, must update the actual treatment process and have tomodernize it. A comparative study was undertaken of the quality of effluents that could be obtained by implementationof biological nutrient removal process li...

  8. Simulation Study of Flap Effects on a Commercial Transport Airplane in Upset Conditions

    Science.gov (United States)

    Cunningham, Kevin; Foster, John V.; Shah, Gautam H.; Stewart, Eric C.; Ventura, Robin N.; Rivers, Robert A.; Wilborn, James E.; Gato, William

    2005-01-01

    As part of NASA's Aviation Safety and Security Program, a simulation study of a twinjet transport airplane crew training simulation was conducted to address fidelity for upset or loss of control conditions and to study the effect of flap configuration in those regimes. Piloted and desktop simulations were used to compare the baseline crew training simulation model with an enhanced aerodynamic model that was developed for high-angle-of-attack conditions. These studies were conducted with various flap configurations and addressed the approach-to-stall, stall, and post-stall flight regimes. The enhanced simulation model showed that flap configuration had a significant effect on the character of departures that occurred during post-stall flight. Preliminary comparisons with flight test data indicate that the enhanced model is a significant improvement over the baseline. Some of the unrepresentative characteristics that are predicted by the baseline crew training simulation for flight in the post-stall regime have been identified. This paper presents preliminary results of this simulation study and discusses key issues regarding predicted flight dynamics characteristics during extreme upset and loss-of-control flight conditions with different flap configurations.

  9. STUDY AND NUMERICAL SIMULATION OF SOLAR SYSTEM FOR AIR HEATING

    Directory of Open Access Journals (Sweden)

    M. Ghodbane

    2016-01-01

    Full Text Available The use of solar energy in sunny countries, is an effective outil for compensate the lack in the energy, their benefits are not related only to its economic benefits but especially for the environmental protection, so we must find solutions to the problems of pollution. This work is a theoretical study of a solar flat plate collector ; air is used as the heat transfer fluid. In this study, we established in first step the calculation of solar radiation in various sites in Algeria (Adrar, El Oued, Bechar, Biskra and Tamanrasset. The second step is the parameters influence study of the sites and climate on the performance of our collector. The results obtained are encouraging for the use of this type in the heating in the winter, also it can be used in different kinds of drying.

  10. Random Telegraph Signal Amplitudes in Sub 100 nm (Decanano) MOSFETs: A 3D 'Atomistic' Simulation Study

    Science.gov (United States)

    Asenov, Asen; Balasubramaniam, R.; Brown, A. R.; Davies, J. H.; Saini, Subhash

    2000-01-01

    In this paper we use 3D simulations to study the amplitudes of random telegraph signals (RTS) associated with the trapping of a single carrier in interface states in the channel of sub 100 nm (decanano) MOSFETs. Both simulations using continuous doping charge and random discrete dopants in the active region of the MOSFETs are presented. We have studied the dependence of the RTS amplitudes on the position of the trapped charge in the channel and on the device design parameters. We have observed a significant increase in the maximum RTS amplitude when discrete random dopants are employed in the simulations.

  11. 3D simulation studies of tokamak plasmas using MHD and extended-MHD models

    International Nuclear Information System (INIS)

    Park, W.; Chang, Z.; Fredrickson, E.; Fu, G.Y.

    1996-01-01

    The M3D (Multi-level 3D) tokamak simulation project aims at the simulation of tokamak plasmas using a multi-level tokamak code package. Several current applications using MHD and Extended-MHD models are presented; high-β disruption studies in reversed shear plasmas using the MHD level MH3D code, ω *i stabilization and nonlinear island saturation of TAE mode using the hybrid particle/MHD level MH3D-K code, and unstructured mesh MH3D ++ code studies. In particular, three internal mode disruption mechanisms are identified from simulation results which agree which agree well with experimental data

  12. Three-dimensional growth simulation: A study of substrate oriented films

    International Nuclear Information System (INIS)

    Besnard, A; Martin, N; Carpentier, L

    2010-01-01

    Monte Carlo simulations are developed to simulate the growth of three-dimensional columnar microstructure in thin films. We are studying in particular oriented microstructure like those produced with the Glancing Angle Deposition technique (GLAD). Some geometrical characteristics of the particles flux, the organization of defect sites on the substrate surface and the atomic surface diffusion are mainly investigated in order to predict the growth processes and the resulting features of the films. This study reports on simulations of thin film growth exhibiting an oblique and zigzag columnar microstructure. Column angle evolution and density are investigated versus incidence angle α or period number n and compared with experimental measurements.

  13. Study and simulation of the time behaviour of MOS transistor devices. Application to a logic assembly

    International Nuclear Information System (INIS)

    Barocas, Marcel

    1974-01-01

    The objective of this research thesis is to determine, by simulation, the time response of devices based on MOS transistors. After a theoretical study of the MOS element, the author develops a transistor model based on its physical components. This model is firstly used to obtain the transistor static characteristics. The author then studies the time response of the inverter logic circuit which is the basic operator of these circuits. Theoretical results are verified by simulation and by experiments. The author then reports a detailed study of the inverter input impedance, and the decoupling property between logic operators in cascade. The simulation confirms the obtained results. Based on this decoupling property, the output time response of a logic chain is studied by using a simulation software. A general method of determination of the output time response is developed with application to a logic assembly [fr

  14. A controlled monitoring study of simulated clandestine graves using 3D ground penetrating radar

    CSIR Research Space (South Africa)

    van Schoor, Michael

    2017-06-01

    Full Text Available A controlled three-dimensional ground penetrating radar monitoring study over simulated clandestine graves was conducted near Pretoria, South Africa, in which the detectability of graves as a function of post-burial interval was assessed...

  15. A RAINFALL SIMULATOR STUDY OF INFILTRATION INTO ARABLE SOILS

    NARCIS (Netherlands)

    WIERDA, A; VEEN, AWL

    Since Hortonian surface runoff is one possible mechanism for the fast transport of agricultural chemicals from arable soils to surface water, more information is needed on its significance in agricultural areas. The present study concerns the sandy soils of the Dutch Cover Sands area, and is based

  16. A Theoretical Study of Subsurface Drainage Model Simulation of ...

    African Journals Online (AJOL)

    A three-dimensional variable-density groundwater flow model, the SEAWAT model, was used to assess the influence of subsurface drain spacing, evapotranspiration and irrigation water quality on salt concentration at the base of the root zone, leaching and drainage in salt affected irrigated land. The study was carried out ...

  17. Simulation Study Of Small Scale Jobshop | Ubani | Journal of ...

    African Journals Online (AJOL)

    This paper examines the impact of strategic change management on the performances of public transport in Osun State, Nigeria. It aimed at determining the role of leadership style in strategic change management; identify in factors that are influencing change process and actual performance of an organization. The study ...

  18. Lung assist devices influence cardio-energetic parameters: Numerical simulation study.

    Science.gov (United States)

    De Lazzari, C; Quatember, B; Recheis, W; Mayr, M; Demertzis, S; Allasia, G; De Rossi, A; Cavoretto, R; Venturino, E; Genuini, I

    2015-08-01

    We aim at an analysis of the effects mechanical ventilators (MVs) and thoracic artificial lungs (TALs) will have on the cardiovascular system, especially on important quantities, such as left and right ventricular external work (EW), pressure-volume area (PVA) and cardiac mechanical efficiency (CME). Our analyses are based on simulation studies which were carried out by using our CARDIOSIM(©) software simulator. At first, we carried out simulation studies of patients undergoing mechanical ventilation (MV) without a thoracic artificial lung (TAL). Subsequently, we conducted simulation studies of patients who had been provided with a TAL, but did not undergo MV. We aimed at describing the patient's physiological characteristics and their variations with time, such as EW, PVA, CME, cardiac output (CO) and mean pulmonary arterial/venous pressure (PAP/PVP). We were starting with a simulation run under well-defined initial conditions which was followed by simulation runs for a wide range of mean intrathoracic pressure settings. Our simulations of MV without TAL showed that for mean intrathoracic pressure settings from negative (-4 mmHg) to positive (+5 mmHg) values, the left and right ventricular EW and PVA, right ventricular CME and CO decreased, whereas left ventricular CME and the PAP increased. The simulation studies of patients with a TAL, comprised all the usual TAL arrangements, viz. configurations "in series" and in parallel with the natural lung and, moreover, hybrid configurations. The main objective of the simulation studies was, as before, the assessment of the hemodynamic response to the application of a TAL. We could for instance show that, in case of an "in series" configuration, a reduction (an increase) in left (right) ventricular EW and PVA values occurred, whereas the best performance in terms of CO can be achieved in the case of an in parallel configuration.

  19. Injector and beam transport simulation study of proton dielectric wall accelerator

    International Nuclear Information System (INIS)

    Zhao, Quantang; Yuan, P.; Zhang, Z.M.; Cao, S.C; Shen, X.K.; Jing, Y.; Ma, Y.Y.; Yu, C.S.; Li, Z.P.; Liu, M.; Xiao, R.Q.; Zhao, H.W.

    2012-01-01

    A simulation study of a short-pulsed proton injector for, and beam transport in, a dielectric wall accelerator (DWA) has been carried out using the particle-in-cell (PIC) code Warp. It was shown that applying “tilt pulse” voltage waveforms on three electrodes enables the production of a shorter bunch by the injector. The fields in the DWA beam tube were simulated using Computer Simulation Technology’s Microwave Studio (CST MWS) package, with various choices for the boundary conditions. For acceleration in the DWA, the beam transport was simulated with Warp, using applied fields obtained by running CST MWS. Our simulations showed that the electric field at the entrance to the DWA represents a challenging issue for the beam transport. We thus simulated a configuration with a mesh at the entrance of the DWA, intended to improve the entrance field. In these latter simulations, a proton bunch was successfully accelerated from 130 keV to about 36 MeV in a DWA with a length of 36.75 cm. As the beam bunch progresses, its transverse dimensions diminish from (roughly) 0.5×0.5 cm to 0.2×0.4 cm. The beam pulse lengthens from 1 cm to 2 cm due to lack of longitudinal compression fields. -- Highlights: ► A pulse proton injector with tilt voltages on the three electrodes was simulated. ► The fields in different part of the DWA were simulated with CST and analyzed. ► The proton beam transport in DWA was simulated with Warp successfully. ► The simulation can help for designing a real DWA.

  20. SED-ML web tools: generate, modify and export standard-compliant simulation studies.

    Science.gov (United States)

    Bergmann, Frank T; Nickerson, David; Waltemath, Dagmar; Scharm, Martin

    2017-04-15

    The Simulation Experiment Description Markup Language (SED-ML) is a standardized format for exchanging simulation studies independently of software tools. We present the SED-ML Web Tools, an online application for creating, editing, simulating and validating SED-ML documents. The Web Tools implement all current SED-ML specifications and, thus, support complex modifications and co-simulation of models in SBML and CellML formats. Ultimately, the Web Tools lower the bar on working with SED-ML documents and help users create valid simulation descriptions. http://sysbioapps.dyndns.org/SED-ML_Web_Tools/ . fbergman@caltech.edu . © The Author 2017. Published by Oxford University Press. All rights reserved. For Permissions, please e-mail: journals.permissions@oup.com

  1. Study on Tensile Properties of Nanoreinforced Epoxy Polymer: Macroscopic Experiments and Nanoscale FEM Simulation Prediction

    Directory of Open Access Journals (Sweden)

    Zhenqing Wang

    2013-01-01

    Full Text Available The effect of nanosilica contents on mechanical properties of the epoxy matrix with some nanoparticle aggregations was studied in macroscopic experiments and nanoscale simulation, particularly with regard to the effective modulus and ultimate stress. Three analytical models were used to obtain the effective elastic modulus of nanoparticle-reinforced composites. Based on Monte-Carlo method, the special program for the automatic generation of 2D random distribution particles without overlapping was developed for nanocomposite modeling. Weight fractions of nanoparticles were converted to volume fractions, in order to coordinate the content unit in the simulation. In numerical analysis, the weak interface strengthening and toughening mechanism was adopted. Virtual crack closure technique (VCCT and extended finite element method (XFEM were used to simulate phenomena of nanoparticle debonding and matrix crack growth. Experimental and simulation results show a good agreement with each other. By way of simulation, the weak interface toughening and strengthening mechanism of nanocomposites is confirmed.

  2. A study on a nano-scale materials simulation using a PC cluster

    International Nuclear Information System (INIS)

    Choi, Deok Kee; Ryu, Han Kyu

    2002-01-01

    Not a few scientists have paid attention to application of molecular dynamics to chemistry, biology and physics. With recent popularity of nano technology, nano-scale analysis has become a major subject in various engineering fields. A underlying nano scale analysis is based on classical molecular theories representing molecular dynamics. Based on Newton's law of motions of particles, the movement of each particles is to be determined by numerical integrations. As the size of computation is closely related with the number of molecules, materials simulation takes up huge amount of computer resources so that it is not until recent days that the application of molecular dynamics to materials simulations draw some attention from many researchers. Thanks to high-performance computers, materials simulation via molecular dynamics looks promising. In this study, a PC cluster consisting of multiple commodity PCs is established and nano scale materials simulations are carried out. Micro-sized crack propagation inside a nano material is displayed by the simulation

  3. Simulation of complex data structures for planning of studies with focus on biomarker comparison.

    Science.gov (United States)

    Schulz, Andreas; Zöller, Daniela; Nickels, Stefan; Beutel, Manfred E; Blettner, Maria; Wild, Philipp S; Binder, Harald

    2017-06-13

    There are a growing number of observational studies that do not only focus on single biomarkers for predicting an outcome event, but address questions in a multivariable setting. For example, when quantifying the added value of new biomarkers in addition to established risk factors, the aim might be to rank several new markers with respect to their prediction performance. This makes it important to consider the marker correlation structure for planning such a study. Because of the complexity, a simulation approach may be required to adequately assess sample size or other aspects, such as the choice of a performance measure. In a simulation study based on real data, we investigated how to generate covariates with realistic distributions and what generating model should be used for the outcome, aiming to determine the least amount of information and complexity needed to obtain realistic results. As a basis for the simulation a large epidemiological cohort study, the Gutenberg Health Study was used. The added value of markers was quantified and ranked in subsampling data sets of this population data, and simulation approaches were judged by the quality of the ranking. One of the evaluated approaches, the random forest, requires original data at the individual level. Therefore, also the effect of the size of a pilot study for random forest based simulation was investigated. We found that simple logistic regression models failed to adequately generate realistic data, even with extensions such as interaction terms or non-linear effects. The random forest approach was seen to be more appropriate for simulation of complex data structures. Pilot studies starting at about 250 observations were seen to provide a reasonable level of information for this approach. We advise to avoid oversimplified regression models for simulation, in particular when focusing on multivariable research questions. More generally, a simulation should be based on real data for adequately reflecting

  4. Simulation of complex data structures for planning of studies with focus on biomarker comparison

    Directory of Open Access Journals (Sweden)

    Andreas Schulz

    2017-06-01

    Full Text Available Abstract Background There are a growing number of observational studies that do not only focus on single biomarkers for predicting an outcome event, but address questions in a multivariable setting. For example, when quantifying the added value of new biomarkers in addition to established risk factors, the aim might be to rank several new markers with respect to their prediction performance. This makes it important to consider the marker correlation structure for planning such a study. Because of the complexity, a simulation approach may be required to adequately assess sample size or other aspects, such as the choice of a performance measure. Methods In a simulation study based on real data, we investigated how to generate covariates with realistic distributions and what generating model should be used for the outcome, aiming to determine the least amount of information and complexity needed to obtain realistic results. As a basis for the simulation a large epidemiological cohort study, the Gutenberg Health Study was used. The added value of markers was quantified and ranked in subsampling data sets of this population data, and simulation approaches were judged by the quality of the ranking. One of the evaluated approaches, the random forest, requires original data at the individual level. Therefore, also the effect of the size of a pilot study for random forest based simulation was investigated. Results We found that simple logistic regression models failed to adequately generate realistic data, even with extensions such as interaction terms or non-linear effects. The random forest approach was seen to be more appropriate for simulation of complex data structures. Pilot studies starting at about 250 observations were seen to provide a reasonable level of information for this approach. Conclusions We advise to avoid oversimplified regression models for simulation, in particular when focusing on multivariable research questions. More generally

  5. The influence of interactions between market segmentation strategy and competition on organizational performance. A simulation study.

    OpenAIRE

    Dolnicar, Sara; Freitag, Roman

    2003-01-01

    A computer simulation study is conducted to explore the interaction of alternative segmentation strategies and the competitiveness of the market environment, a goal that can neither be tackled by purely analytic approaches nor is sufficient and undistorted real market data available to deduct findings in an empirical manner. The fundamental idea of the simulation is to increase competition in the artificial marketplace and to study the influence of segmentation strategy and varying market con...

  6. An IT-enabled supply chain model: a simulation study

    Science.gov (United States)

    Cannella, Salvatore; Framinan, Jose M.; Barbosa-Póvoa, Ana

    2014-11-01

    During the last decades, supply chain collaboration practices and the underlying enabling technologies have evolved from the classical electronic data interchange (EDI) approach to a web-based and radio frequency identification (RFID)-enabled collaboration. In this field, most of the literature has focused on the study of optimal parameters for reducing the total cost of suppliers, by adopting operational research (OR) techniques. Herein we are interested in showing that the considered information technology (IT)-enabled structure is resilient, that is, it works well across a reasonably broad range of parameter settings. By adopting a methodological approach based on system dynamics, we study a multi-tier collaborative supply chain. Results show that the IT-enabled supply chain improves operational performance and customer service level. Nonetheless, benefits for geographically dispersed networks are of minor entity.

  7. Beam Loss Simulation Studies for ALS Top-Off Operation

    CERN Document Server

    Nishimura, Hiroshi; Robin, David; Steier, Christoph

    2005-01-01

    The ALS is planning to operate with top-off injection at higher beam currents and smaller vertical beam size. As part of a radiation safety study for top-off, we carried out two kinds of tracking studies: (1) to confirm that the injected beam cannot go into users' photon beam lines, and (2) to control the location of beam dump when the storage ring RF is tripped. (1) is done by tracking electrons from a photon beam line to the injection sector inversely by including the magnetic field profiles, varying the field strength with geometric aperture limits to conclude that it is impossible. (2) is done by tracking an electron with radiation in the 6-dim space for different combinations of vertical scrapers for the realistic lattice with errors.

  8. Local dose enhancement in radiation therapy: Monte Carlo simulation study

    International Nuclear Information System (INIS)

    Silva, Laura E. da; Nicolucci, Patricia

    2014-01-01

    The development of nanotechnology has boosted the use of nanoparticles in radiation therapy in order to achieve greater therapeutic ratio between tumor and healthy tissues. Gold has been shown to be most suitable to this task due to the high biocompatibility and high atomic number, which contributes to a better in vivo distribution and for the local energy deposition. As a result, this study proposes to study, nanoparticle in the tumor cell. At a range of 11 nm from the nanoparticle surface, results have shown an absorbed dose 141 times higher for the medium with the gold nanoparticle compared to the water for an incident energy spectrum with maximum photon energy of 50 keV. It was also noted that when only scattered radiation is interacting with the gold nanoparticles, the dose was 134 times higher compared to enhanced local dose that remained significant even for scattered radiation. (author)

  9. Simulating direct shear tests with the Bullet physics library: A validation study.

    Science.gov (United States)

    Izadi, Ehsan; Bezuijen, Adam

    2018-01-01

    This study focuses on the possible uses of physics engines, and more specifically the Bullet physics library, to simulate granular systems. Physics engines are employed extensively in the video gaming, animation and movie industries to create physically plausible scenes. They are designed to deliver a fast, stable, and optimal simulation of certain systems such as rigid bodies, soft bodies and fluids. This study focuses exclusively on simulating granular media in the context of rigid body dynamics with the Bullet physics library. The first step was to validate the results of the simulations of direct shear testing on uniform-sized metal beads on the basis of laboratory experiments. The difference in the average angle of mobilized frictions was found to be only 1.0°. In addition, a very close match was found between dilatancy in the laboratory samples and in the simulations. A comprehensive study was then conducted to determine the failure and post-failure mechanism. We conclude with the presentation of a simulation of a direct shear test on real soil which demonstrated that Bullet has all the capabilities needed to be used as software for simulating granular systems.

  10. Interactive simulations for promoting transdisciplinary understanding: a case study of the Western Cape fisheries, South Africa

    Directory of Open Access Journals (Sweden)

    Cecile Proches

    2012-07-01

    Full Text Available Simulations have proven beneficial in enabling participants from various backgrounds to meaningfully engage in learning from experience. The aim of this paper is to investigate how interactive simulations can play a role in navigating the changes faced in a multi- stakeholder setting, characterised by users dependent on marine resources and an authorising institution. Relevant literature in the areas of simulation and gaming, change management, systems thinking, and complexity theory was examined. A qualitative research approach and purposive sampling were employed. Interviews were first conducted with diverse stakeholders in the Western Cape fisheries of South Africa to determine the issues. A simulation was thereafter designed. The main findings from this study indicate that simulation use illustrates how the various stakeholders in a system interact, and how their actions and decisions influence each other. The simulation may be used in other areas of natural resource management, as well as in other kinds of multi- stakeholder scenarios. Keywords: Simulation and gaming, Change management, Fisheries, Multi-stakeholder scenarios, Systems thinking, Complexity theory Disciplines: Conflict Resolution, Leadership Studies, Management Studies, Natural Resource Management

  11. A hybrid simulation approach for integrating safety behavior into construction planning: An earthmoving case study.

    Science.gov (United States)

    Goh, Yang Miang; Askar Ali, Mohamed Jawad

    2016-08-01

    One of the key challenges in improving construction safety and health is the management of safety behavior. From a system point of view, workers work unsafely due to system level issues such as poor safety culture, excessive production pressure, inadequate allocation of resources and time and lack of training. These systemic issues should be eradicated or minimized during planning. However, there is a lack of detailed planning tools to help managers assess the impact of their upstream decisions on worker safety behavior. Even though simulation had been used in construction planning, the review conducted in this study showed that construction safety management research had not been exploiting the potential of simulation techniques. Thus, a hybrid simulation framework is proposed to facilitate integration of safety management considerations into construction activity simulation. The hybrid framework consists of discrete event simulation (DES) as the core, but heterogeneous, interactive and intelligent (able to make decisions) agents replace traditional entities and resources. In addition, some of the cognitive processes and physiological aspects of agents are captured using system dynamics (SD) approach. The combination of DES, agent-based simulation (ABS) and SD allows a more "natural" representation of the complex dynamics in construction activities. The proposed hybrid framework was demonstrated using a hypothetical case study. In addition, due to the lack of application of factorial experiment approach in safety management simulation, the case study demonstrated sensitivity analysis and factorial experiment to guide future research. Copyright © 2015 Elsevier Ltd. All rights reserved.

  12. Temperature dependence of creep compliance of highly cross-linked epoxy: A molecular simulation study

    International Nuclear Information System (INIS)

    Khabaz, Fardin; Khare, Ketan S.; Khare, Rajesh

    2014-01-01

    We have used molecular dynamics (MD) simulations to study the effect of temperature on the creep compliance of neat cross-linked epoxy. Experimental studies of mechanical behavior of cross-linked epoxy in literature commonly report creep compliance values, whereas molecular simulations of these systems have primarily focused on the Young’s modulus. In this work, in order to obtain a more direct comparison between experiments and simulations, atomistically detailed models of the cross-linked epoxy are used to study their creep compliance as a function of temperature using MD simulations. The creep tests are performed by applying a constant tensile stress and monitoring the resulting strain in the system. Our results show that simulated values of creep compliance increase with an increase in both time and temperature. We believe that such calculations of the creep compliance, along with the use of time temperature superposition, hold great promise in connecting the molecular insight obtained from molecular simulation at small length- and time-scales with the experimental behavior of such materials. To the best of our knowledge, this work is the first reported effort that investigates the creep compliance behavior of cross-linked epoxy using MD simulations

  13. A study on the usefulness of high fidelity patient simulation in undergraduate medical education

    Directory of Open Access Journals (Sweden)

    Bikramjit Pal

    2018-01-01

    Full Text Available Introduction: Simulation is the imitation of the operation of a real-world process or system over time. Innovative simulation training solutions are now being used to train medical professionals in an attempt to reduce the number of safety concerns that have adverse effects on the patients. Objectives: (a To determine its usefulness as a teaching or learning tool for management of surgical emergencies, both in the short term and medium term by students’ perception. (b To plan future teaching methodology regarding hi-fidelity simulation based on the study outcomes and re-assessment of the current training modules. Methods: Quasi-experimental time series design with pretest-posttest interventional study. Quantitative data was analysed in terms of Mean, Standard Deviation and standard error of Mean. Statistical tests of significance like Repeated Measure of Analysis of Variance (ANOVA were used for comparisons. P value < 0.001 was considered to be statistically significant. Results: The students opined that the simulated sessions on high fidelity simulators had encouraged their active participation which was appropriate to their current level of learning. It helped them to think fast and the training sessions resembled a real life situation. The study showed that learning had progressively improved with each session of simulation with corresponding decrease in stress. Conclusion: Implementation of high fidelity simulation based learning in our Institute had been perceived favourably by a large number of students in enhancing their knowledge over time in management of trauma and surgical emergencies.

  14. The Power of Phase I Studies to Detect Clinical Relevant QTc Prolongation: A Resampling Simulation Study

    Directory of Open Access Journals (Sweden)

    Georg Ferber

    2015-01-01

    Full Text Available Concentration-effect (CE models applied to early clinical QT data from healthy subjects are described in the latest E14 Q&A document as promising analysis to characterise QTc prolongation. The challenges faced if one attempts to replace a TQT study by thorough ECG assessments in Phase I based on CE models are the assurance to obtain sufficient power and the establishment of a substitute for the positive control to show assay sensitivity providing protection against false negatives. To demonstrate that CE models in small studies can reliably predict the absence of an effect on QTc, we investigated the role of some key design features in the power of the analysis. Specifically, the form of the CE model, inclusion of subjects on placebo, and sparse sampling on the performance and power of this analysis were investigated. In this study, the simulations conducted by subsampling subjects from 3 different TQT studies showed that CE model with a treatment effect can be used to exclude small QTc effects. The number of placebo subjects was also shown to increase the power to detect an inactive drug preventing false positives while an effect can be underestimated if time points around tmax are missed.

  15. Management of Nitrate m Groundwater: A Simulation Study

    Directory of Open Access Journals (Sweden)

    M. Ahmed

    2001-01-01

    Full Text Available Agriculture may cause nitrate and other chemicals to enter into groundwater systems. Nitrate in drinking water is considered a health hazard. A study was conducted to assess the extent of nitrate pollution of groundwater caused by agriculture and to evaluate the possibility of using the LEACHN model to manage nitrate entry into groundwater of agricultural areas of Al-Batinah, which is the most important agricultural region of Oman. Groundwater samples were collected and analyzed to assess the problem and to detect possible trends. Soil sampling and analyses were done to demonstrate the difference in the nitrate concentration in agricultural and non-agricultural soils. A questionnaire survey was conducted to gather information on agricultural practices, fertilizer input, and other possible sources of nitrate pollution. Results from the study show that 23% of groundwater samples have a concentration of nitrate-N concentration of 10 mg/l and 34% samples exceed 8 mg/l. Agricultural soils have higher levels of nitrate compared to non- agricultural soils. Results also demonstrate that nitrate levels in groundwater in Al-Batinah are rising. Application of the ‘LEACHN’ model demonstrated its suitability for use as a management tool to reduce nitrate leaching to groundwater by controlling fertilizer and water input.

  16. Modelling and Simulation of TCPAR for Power System Flow Studies

    Directory of Open Access Journals (Sweden)

    Narimen Lahaçani AOUZELLAG

    2012-12-01

    Full Text Available In this paper, the modelling of Thyristor Controlled Phase Angle Regulator ‘TCPAR’ for power flow studies and the role of that modelling in the study of Flexible Alternating Current Transmission Systems ‘FACTS’ for power flow control are discussed. In order to investigate the impact of TCPAR on power systems effectively, it is essential to formulate a correct and appropriate model for it. The TCPAR, thus, makes it possible to increase or decrease the power forwarded in the line where it is inserted in a considerable way, which makes of it an ideal tool for this kind of use. Knowing that the TCPAR does not inject any active power, it offers a good solution with a less consumption. One of the adverse effects of the TCPAR is the voltage drop which it causes in the network although it is not significant. To solve this disadvantage, it is enough to introduce a Static VAR Compensator ‘SVC’ into the electrical network which will compensate the voltages fall and will bring them back to an acceptable level.

  17. Simulation studies of gas and plasma-based charge strippers

    Energy Technology Data Exchange (ETDEWEB)

    Haas, Oliver Sebastian [Institut fuer Theorie Elektromagnetischer Felder, Technische Univ. Darmstadt (Germany); Boine-Frankenheim, Oliver [Institut fuer Theorie Elektromagnetischer Felder, Technische Univ. Darmstadt (Germany); GSI Helmholtz Centre for Heavy Ion Research, Darmstadt (Germany)

    2016-07-01

    Charge stripping of heavy ion beams at high intensities is a major challenge in current and future facilities with high intensity heavy ion beams. Conventional stripping techniques are limited in their applicability, e.g. solid carbon foils suffer from short lifetimes at high intensities and gas strippers usually achieve only low charge states. One possible alternative is the use of a plasma as a stripping medium. The presented work focuses on theoretical studies of the interaction of an heavy ion beam with a plasma and accompanying effects in possible charge strippers. The main interest in the presented studies is the final charge state distribution of the ion beam. Different models for solving the corresponding rate equations were developed, taking into account ionization, recombination, energy loss and straggling processes. Sophisticated models, e.g. for ionization cross sections, as well as limits and applicability of simplified models are discussed. Quantitative results are presented in form an overview of the charge state distributions of different - conventional and novel - charge stripping media. Furthermore comparisons are done with charge state distributions of available experimental data. Typical practically relevant target conditions are discussed as well as deterioration of beam quality.

  18. Systematic parameter study of dynamo bifurcations in geodynamo simulations

    Science.gov (United States)

    Petitdemange, Ludovic

    2018-04-01

    We investigate the nature of the dynamo bifurcation in a configuration applicable to the Earth's liquid outer core, i.e. in a rotating spherical shell with thermally driven motions with no-slip boundaries. Unlike in previous studies on dynamo bifurcations, the control parameters have been varied significantly in order to deduce general tendencies. Numerical studies on the stability domain of dipolar magnetic fields found a dichotomy between non-reversing dipole-dominated dynamos and the reversing non-dipole-dominated multipolar solutions. We show that, by considering weak initial fields, the above transition disappears and is replaced by a region of bistability for which dipolar and multipolar dynamos coexist. Such a result was also observed in models with free-slip boundaries in which the geostrophic zonal flow can develop and participate to the dynamo mechanism for non-dipolar fields. We show that a similar process develops in no-slip models when viscous effects are reduced sufficiently. The following three regimes are distinguished: (i) Close to the onset of convection (Rac) with only the most critical convective mode (wave number) being present, dynamos set in supercritically in the Ekman number regime explored here and are dipole-dominated. Larger critical magnetic Reynolds numbers indicate that they are particularly inefficient. (ii) in the range 3 10) , the relative importance of zonal flows increases with Ra in non-magnetic models. The field topology depends on the magnitude of the initial magnetic field. The dipolar branch has a subcritical behavior whereas the multipolar branch has a supercritical behavior. By approaching more realistic parameters, the extension of this bistable regime increases. A hysteretic behavior questions the common interpretation for geomagnetic reversals. Far above the dynamo threshold (by increasing the magnetic Prandtl number), Lorentz forces contribute to the first order force balance, as predicted for planetary dynamos. When

  19. Computer simulation studies of high energy collision cascades

    International Nuclear Information System (INIS)

    Robinson, M.T.

    1991-07-01

    A modified binary collision approximation allowing the proper order of the collisions in time was used to study cascades in Cu and Au at primary kinetic energies up to 100 keV. Nonlinearities were approximated by letting already-stopped cascade atoms become targets in later collisions, using an improved method of locating potential targets to extend the calculations to energies much higher than heretofore. Beside the effect of the approximate nonlinearity, the effect of thermal disorder in the targets was examined. Target redisplacements reduce the damage in Cu by 3% at most, but in Au they reduce it by amounts up to 20% at 100 keV. Thermal disorder is also important: by disrupting crystal effects, the damage is reduced significantly. 11 refs., 4 figs

  20. Studies on simulated nuclear waste of mixed solvent type

    International Nuclear Information System (INIS)

    Aggarwal, S.

    1989-09-01

    Caesium 137, strontium 90 and ruthenium 106 are among the longest lived fission products present in reprocessing wastes and are therefore considered to be a long term hazard to the environment. A method for removal of 137-Cs, 90-Sr and 106-Ru from the nuclear waste is by ion-exchange and sorption. Radiochemical methods were employed to investigate the uptake of 137-Cs, 90-Sr and 106-Ru by synthetic type A, X, Y, zeolites and by mordenite and clinoptilolite. The solvents employed were tributylphosphate (TBP) and kerosene (OK). The dependence of the exchange process on time was studied at room temperature. The exchange equilibrium was strongly dependent on time during the first hour but then attained equilibrium. It was also noted that the distribution coefficient (Kd) values for 137-Cs were higher than those for 90-Sr which were higher than those for 106-Ru. Thus the order of extraction was: 137-Cs > 90-Sr > 106-Ru. Ethanol was also used as the solvent to see the effect on the Kds by varying the amount of water present, i.e. from 0% water to 10% water. It was observed that the Kd increased with an increase in water content. The effect of pH and different ratios of TBP:OK were also studied. There was no relationship between the Kds and the different ratios. Some work was also done on the adsorption of 137-Cs on cements and cement phases. The sorption of 137-Cs on to all types of cements was low. (author)

  1. Virtual gaming simulation of a mental health assessment: A usability study.

    Science.gov (United States)

    Verkuyl, Margaret; Romaniuk, Daria; Mastrilli, Paula

    2018-05-18

    Providing safe and realistic virtual simulations could be an effective way to facilitate the transition from the classroom to clinical practice. As nursing programs begin to include virtual simulations as a learning strategy; it is critical to first assess the technology for ease of use and usefulness. A virtual gaming simulation was developed, and a usability study was conducted to assess its ease of use and usefulness for students and faculty. The Technology Acceptance Model provided the framework for the study, which included expert review and testing by nursing faculty and nursing students. This study highlighted the importance of assessing ease of use and usefulness in a virtual game simulation and provided feedback for the development of an effective virtual gaming simulation. The study participants said the virtual gaming simulation was engaging, realistic and similar to a clinical experience. Participants found the game easy to use and useful. Testing provided the development team with ideas to improve the user interface. The usability methodology provided is a replicable approach to testing virtual experiences before a research study or before implementing virtual experiences into curriculum. Copyright © 2018 Elsevier Ltd. All rights reserved.

  2. Study of physical properties, gas generation and gas retention in simulated Hanford waste

    International Nuclear Information System (INIS)

    Bryan, S.A.; Pederson, L.R.; Scheele, R.D.

    1993-04-01

    The purpose of this study was to establish the chemical and physical processes responsible for the generation and retention of gases within high-level waste from Tank 101-SY on the Hanford Site. This research, conducted using simulated waste on a laboratory scale, supports the development of mitigation/remediation strategies for Tank 101-SY. Simulated waste formulations are based on actual waste compositions. Selected physical properties of the simulated waste are compared to properties of actual Tank 101-SY waste samples. Laboratory studies using aged simulated waste show that significant gas generation occurs thermally at current tank temperatures (∼60 degrees C). Gas compositions include the same gases produced in actual tank waste, primarily N 2 , N 2 O, and H 2 . Gas stoichiometries have been shown to be greatly influenced by several organic and inorganic constituents within the simulated waste. Retention of gases in the simulated waste is in the form of bubble attachment to solid particles. This attachment phenomenon is related to the presence of organic constituents (HEDTA, EDTA, and citrate) of the simulated waste. A mechanism is discussed that relates the gas bubble/particle interactions to the partially hydrophobic surface produced on the solids by the organic constituents

  3. Study on applicability of numerical simulation to evaluation of gas entrainment due to free surface vortex

    International Nuclear Information System (INIS)

    Ito, Kei; Kunugi, Tomoaki; Ohshima, Hiroyuki

    2008-01-01

    An onset condition of gas entrainment (GE) due to free surface vortex has been studied to establish a design of sodium-cooled fast reactor with a higher coolant velocity than conventional designs. Numerous investigations have been conducted experimentally and theoretically; however, the universal onset condition of the GE has not been determined yet due to the nonlinear characteristics of the GE. Recently, we have been studying numerical simulation methods as a promising method to evaluate GE, instead of the reliable but costly real-scale tests. In this paper, the applicability of the numerical simulation methods to the evaluation of the GE is discussed. For the purpose, a quasi-steady vortex in a cylindrical tank and a wake vortex (unsteady vortex) in a rectangular channel were numerically simulated using the volume-of-fluid type two-phase flow calculation method. The simulated velocity distributions and free surface shapes of the quasi-steady vortex showed good (not perfect, however) agreements with experimental results when a fine mesh subdivision and a high-order discretization scheme were employed. The unsteady behavior of the wake vortex was also simulated with high accuracy. Although the onset condition of the GE was slightly underestimated in the simulation results, the applicability of the numerical simulation methods to the GE evaluation was confirmed. (author)

  4. Computerized adaptive measurement of depression: A simulation study

    Directory of Open Access Journals (Sweden)

    Mammen Oommen

    2004-05-01

    Full Text Available Abstract Background Efficient, accurate instruments for measuring depression are increasingly important in clinical practice. We developed a computerized adaptive version of the Beck Depression Inventory (BDI. We examined its efficiency and its usefulness in identifying Major Depressive Episodes (MDE and in measuring depression severity. Methods Subjects were 744 participants in research studies in which each subject completed both the BDI and the SCID. In addition, 285 patients completed the Hamilton Depression Rating Scale. Results The adaptive BDI had an AUC as an indicator of a SCID diagnosis of MDE of 88%, equivalent to the full BDI. The adaptive BDI asked fewer questions than the full BDI (5.6 versus 21 items. The adaptive latent depression score correlated r = .92 with the BDI total score and the latent depression score correlated more highly with the Hamilton (r = .74 than the BDI total score did (r = .70. Conclusions Adaptive testing for depression may provide greatly increased efficiency without loss of accuracy in identifying MDE or in measuring depression severity.

  5. Monte Carlo simulations for generic granite repository studies

    Energy Technology Data Exchange (ETDEWEB)

    Chu, Shaoping [Los Alamos National Laboratory; Lee, Joon H [SNL; Wang, Yifeng [SNL

    2010-12-08

    In a collaborative study between Los Alamos National Laboratory (LANL) and Sandia National Laboratories (SNL) for the DOE-NE Office of Fuel Cycle Technologies Used Fuel Disposition (UFD) Campaign project, we have conducted preliminary system-level analyses to support the development of a long-term strategy for geologic disposal of high-level radioactive waste. A general modeling framework consisting of a near- and a far-field submodel for a granite GDSE was developed. A representative far-field transport model for a generic granite repository was merged with an integrated systems (GoldSim) near-field model. Integrated Monte Carlo model runs with the combined near- and farfield transport models were performed, and the parameter sensitivities were evaluated for the combined system. In addition, a sub-set of radionuclides that are potentially important to repository performance were identified and evaluated for a series of model runs. The analyses were conducted with different waste inventory scenarios. Analyses were also conducted for different repository radionuelide release scenarios. While the results to date are for a generic granite repository, the work establishes the method to be used in the future to provide guidance on the development of strategy for long-term disposal of high-level radioactive waste in a granite repository.

  6. Simulation study on the maximum continuous working condition of a power plant boiler

    Science.gov (United States)

    Wang, Ning; Han, Jiting; Sun, Haitian; Cheng, Jiwei; Jing, Ying'ai; Li, Wenbo

    2018-05-01

    First of all, the boiler is briefly introduced to determine the mathematical model and the boundary conditions, then the boiler under the BMCR condition numerical simulation study, and then the BMCR operating temperature field analysis. According to the boiler actual test results and the hot BMCR condition boiler output test results, the simulation results are verified. The main conclusions are as follows: the position and size of the inscribed circle in the furnace and the furnace temperature distribution and test results under different elevation are compared and verified; Accuracy of numerical simulation results.

  7. Eighteenth Workshop on Recent Developments in Computer Simulation Studies in Condensed Matter Physics

    CERN Document Server

    Landau, David P; Schüttler, Heinz-Bernd; Computer Simulation Studies in Condensed-Matter Physics XVIII

    2006-01-01

    This volume represents a "status report" emanating from presentations made during the 18th Annual Workshop on Computer Simulations Studies in Condensed Matter Physics at the Center for Simulational Physics at the University of Georgia in March 2005. It provides a broad overview of the most recent advances in the field, spanning the range from statistical physics to soft condensed matter and biological systems. Results on nanostructures and materials are included as are several descriptions of advances in quantum simulations and quantum computing as well as.methodological advances.

  8. Monte Carlo simulation study of the muon-induced neutron flux at LNGS

    International Nuclear Information System (INIS)

    Persiani, R.; Garbini, M.; Massoli, F.; Sartorelli, G; Selvi, M.

    2011-01-01

    Muon-induced neutrons are ultimate background for all the experiments searching for rare events in underground laboratories. Several measurements and simulations were performed concerning the neutron production and propagation but there are disagreements between experimental data and simulations. In this work we present our Monte-Carlo simulation study, based on Geant4, to estimate the muon-induced neutron flux at LNGS. The obtained integral flux of neutrons above 1 MeV is 2.31 x 10 -10 n/cm 2 /s.

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

    DEFF Research Database (Denmark)

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

    2011-01-01

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

  10. Studies of turbulent round jets through experimentation, simulation, and modeling

    Science.gov (United States)

    Keedy, Ryan

    This thesis studies the physics of the turbulent round jet. In particular, it focuses on three different problems that have the turbulent round jet as their base flow. The first part of this thesis examines a compressible turbulent round jet at its sonic condition. We investigate the shearing effect such a jet has when impinging on a solid surface that is perpendicular to the flow direction. We report on experiments to evaluate the jet's ability to remove different types of explosive particles from a glass surface. Theoretical analysis revealed trends and enabled modeling to improve the predictability of particle removal for various jet conditions. The second part of thesis aims at developing a non-intrusive measurement technique for free-shear turbulent flows in nature. Most turbulent jet investigations in the literature, both in the laboratory and in the field, required specialized intrusive instrumentation and/or complex optical setups. There are many situations in naturally-occurring flows where the environment may prove too hostile or remote for existing instrumentation. We have developed a methodology for analyzing video of the exterior of a naturally-occurring flow and calculating the flow velocity. We found that the presence of viscosity gradients affects the velocity analysis. While these effects produce consistent, predictable changes, we became interested in the mechanism by which the viscosity gradients affect the mixing and development of the turbulent round jet. We conducted a stability analysis of the axisymmetric jet when a viscosity gradient is present. Finally, the third problem addressed in this thesis is the growth of liquid droplets by condensation in a turbulent round jet. A vapor-saturated turbulent jet issues into a cold, dry environment. The resulting mixing produces highly inhomogeneous regions of supersaturation, where droplets grow and evaporate. Non-linear interactions between the droplet growth rate and the supersaturation field make

  11. Pilot Study: Impact of Computer Simulation on Students' Economic Policy Performance. Pilot Study.

    Science.gov (United States)

    Domazlicky, Bruce; France, Judith

    Fiscal and monetary policies taught in macroeconomic principles courses are concepts that might require both lecture and simulation methods. The simulation models, which apply the principles gleened from comparative statistics to a dynamic world, may give students an appreciation for the problems facing policy makers. This paper is a report of a…

  12. Simulated dose reduction by adding artificial noise to measured raw data: A validation study

    International Nuclear Information System (INIS)

    Soederberg, M.; Gunnarsson, M.; Nilsson, M.

    2010-01-01

    The purpose of this study was to verify and validate a noise simulation tool called Dose Tutor (VAMP GmbH) in terms of level and texture of the simulated noise. By adding artificial noise to measured computed tomography (CT) raw data, a scan acquired with a lower dose (mAs) than the actual one can be simulated. A homogeneous polyethylene phantom and an anthropomorphic chest phantom were scanned for different mAs levels, tube voltages, slice thicknesses and reconstruction kernels. The simulated noise levels were compared with the noise levels in real transverse slice images actually acquired with corresponding mAs values. In general, the noise comparisons showed acceptable agreement in magnitude (<20% deviation in pixel standard deviation). Also, the calculated noise power spectra were similar, which indicates that the noise texture is correctly reproduced. In conclusion, this study establishes that the Dose Tutor might be a useful tool for estimating the dose reduction potential for CT protocols. (authors)

  13. PEPT: An invaluable tool for 3-D particle tracking and CFD simulation verification in hydrocyclone studies

    Directory of Open Access Journals (Sweden)

    Hoffmann Alex C.

    2013-05-01

    Full Text Available Particle tracks in a hydrocyclone generated both experimentally by positron emission particle tracking (PEPT and numerically with Eulerian-Lagranian CFD have been studied and compared. A hydrocyclone with a cylinder-on-cone design was used in this study, the geometries used in the CFD simulations and in the experiments being identical. It is shown that it is possible to track a fast-moving particle in a hydrocyclone using PEPT with high temporal and spatial resolutions. The numerical 3-D particle trajectories were generated using the Large Eddy Simulation (LES turbulence model for the fluid and Lagrangian particle tracking for the particles. The behaviors of the particles were analyzed in detail and were found to be consistent between experiments and CFD simulations. The tracks of the particles are discussed and related to the fluid flow field visualized in the CFD simulations using the cross-sectional static pressure distribution.

  14. A new solver for granular avalanche simulation: Indoor experiment verification and field scale case study

    Science.gov (United States)

    Wang, XiaoLiang; Li, JiaChun

    2017-12-01

    A new solver based on the high-resolution scheme with novel treatments of source terms and interface capture for the Savage-Hutter model is developed to simulate granular avalanche flows. The capability to simulate flow spread and deposit processes is verified through indoor experiments of a two-dimensional granular avalanche. Parameter studies show that reduction in bed friction enhances runout efficiency, and that lower earth pressure restraints enlarge the deposit spread. The April 9, 2000, Yigong avalanche in Tibet, China, is simulated as a case study by this new solver. The predicted results, including evolution process, deposit spread, and hazard impacts, generally agree with site observations. It is concluded that the new solver for the Savage-Hutter equation provides a comprehensive software platform for granular avalanche simulation at both experimental and field scales. In particular, the solver can be a valuable tool for providing necessary information for hazard forecasts, disaster mitigation, and countermeasure decisions in mountainous areas.

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

    Science.gov (United States)

    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.

  16. A simulation study of enhancement duration in three-dimensional contrast-enhanced MR angiography

    International Nuclear Information System (INIS)

    Ohkubo, Masaki; Ohgoshi, Yukio; Inoue, Tomoko; Naito, Kenichi; Suzuki, Kiyotaka

    2001-01-01

    In our study on three-dimensional (3D) contrast-enhanced MR angiography we performed a computer simulation to investigate quantitative vessel visibility. In the simulation, we evaluated the relative loss of signal intensity in a vessel due to shortened duration of contrast-enhancement. The mid-point of enhancement-duration was assumed to be at the point in which the data in the center of k-space (k y axis) was acquired. Signal intensity of a vessel decreased as the enhancement-duration was shortened and the diameter of the vessel was decreased. When the duration was shortened 40%, the signal intensity of a vessel in which the diameter was more than 2 pixels was preserved by approximately 70% or more. This suggests that the vessel visibility is high. When the duration was shortened 20%, the signal intensity of a vessel in which the diameter was less than 2 pixels decreased to less than approximately 40% or less. The simulation was confirmed by using 3D MR angiography with a tube phantom filled with Gd-DTPA to simulate a vessel model. At anytime during data acquisition, we could set the phantom on the region being scanned or take it out by using the ''pause'' function of the MR scanner. This made it possible to change the enhancement-duration to match the simulation. Results of the phantom study were comparable to those of the simulation, suggesting that the simulation was valid. Our results and simple techniques for both the simulation and the phantom study using the ''pause'' function, were considered useful in the study of 3D MR angiography. (author)

  17. Study of the quantitative analysis approach of maintenance by the Monte Carlo simulation method

    International Nuclear Information System (INIS)

    Shimizu, Takashi

    2007-01-01

    This study is examination of the quantitative valuation by Monte Carlo simulation method of maintenance activities of a nuclear power plant. Therefore, the concept of the quantitative valuation of maintenance that examination was advanced in the Japan Society of Maintenology and International Institute of Universality (IUU) was arranged. Basis examination for quantitative valuation of maintenance was carried out at simple feed water system, by Monte Carlo simulation method. (author)

  18. First-principles molecular dynamics simulation study on electrolytes for use in redox flow battery

    Science.gov (United States)

    Choe, Yoong-Kee; Tsuchida, Eiji; Tokuda, Kazuya; Ootsuka, Jun; Saito, Yoshihiro; Masuno, Atsunobu; Inoue, Hiroyuki

    2017-11-01

    Results of first-principles molecular dynamics simulations carried out to investigate structural aspects of electrolytes for use in a redox flow battery are reported. The electrolytes studied here are aqueous sulfuric acid solutions where its property is of importance for dissolving redox couples in redox flow battery. The simulation results indicate that structural features of the acid solutions depend on the concentration of sulfuric acid. Such dependency arises from increase of proton dissociation from sulfuric acid.

  19. Individualized feedback during simulated laparoscopic training:a mixed methods study.

    Science.gov (United States)

    Ahlborg, Liv; Weurlander, Maria; Hedman, Leif; Nisel, Henry; Lindqvist, Pelle G; Felländer-Tsai, Li; Enochsson, Lars

    2015-07-29

    This study aimed to explore the value of individualized feedback on performance, flow and self-efficacy during simulated laparoscopy. Furthermore, we wished to explore attitudes towards feedback and simulator training among medical students. Sixteen medical students were included in the study and randomized to laparoscopic simulator training with or without feedback. A teacher provided individualized feedback continuously throughout the procedures to the target group. Validated questionnaires and scales were used to evaluate self-efficacy and flow. The Mann-Whitney U test was used to evaluate differences between groups regarding laparoscopic performance (instrument path length), self-efficacy and flow. Qualitative data was collected by group interviews and interpreted using inductive thematic analyses. Sixteen students completed the simulator training and questionnaires. Instrument path length was shorter in the feedback group (median 3.9 m; IQR: 3.3-4.9) as compared to the control group (median 5.9 m; IQR: 5.0-8.1), pfeedback group were more concentrated on the task and also more anxious. Both groups had high ambitions to succeed and also expressed the importance of getting feedback. The authenticity of the training scenario was important for the learning process. This study highlights the importance of individualized feedback during simulated laparoscopy training. The next step is to further optimize feedback and to transfer standardized and individualized feedback from the simulated setting to the operating room.

  20. The Use of Instructional Simulations to Support Classroom Teaching: A Crisis Communication Case Study

    Science.gov (United States)

    Shifflet, Mark; Brown, Jane

    2006-01-01

    The purpose of this study was to investigate how exposure to classroom instruction affected the use of a computer simulation that was designed to provide students an opportunity to apply material presented in class. The study involved an analysis of a computer-based crisis communication case study designed for a college-level public relations…

  1. Simulation of fruit pallet movement in the port of Durban: A case study

    African Journals Online (AJOL)

    This paper gives an overview of a discrete-event simulation study that was performed on pallet movement at Fresh Produce Terminals in the port of Durban, South Africa. The study formed part of an extended study of the logistics infrastructure of the South African fresh fruit industry and its export supply chain. The focus in ...

  2. Validation study of a computer-based open surgical trainer: SimPraxis(®) simulation platform.

    Science.gov (United States)

    Tran, Linh N; Gupta, Priyanka; Poniatowski, Lauren H; Alanee, Shaheen; Dall'era, Marc A; Sweet, Robert M

    2013-01-01

    Technological advances have dramatically changed medical education, particularly in the era of work-hour restrictions, which increasingly highlights a need for novel methods to teach surgical skills. The purpose of this study was to evaluate the validity of a novel, computer-based, interactive, cognitive simulator for training surgeons to perform pelvic lymph node dissection (PLND). Eight prostate cancer experts evaluated the content of the simulator. Contextual aspects of the simulator were rated on a five-point Likert scale. The experts and nine first-year residents completed a simulated PLND. Time and deviations were logged, and the results were compared between experts and novices using the Mann-Whitney test. Before training, 88% of the experts felt that a validated simulator would be useful for PLND training. After testing, 100% of the experts felt that it would be more useful than standard video training. Eighty-eight percent stated that they would like to see the simulator in the curriculum of residency programs and 56% thought it would be useful for accreditation purposes. The experts felt that the simulator aided in overall understanding, training indications, concepts and steps of the procedure, training how to use an assistant, and enhanced the knowledge of anatomy. Median performance times taken by experts and interns to complete a PLND procedure on the simulator were 12.62 and 23.97 minutes, respectively. Median deviation from the incorporated procedure pathway for experts was 24.5 and was 89 for novices. We describe an interactive, computer-based simulator designed to assist in mastery of the cognitive steps of an open surgical procedure. This platform is intuitive and flexible, and could be applied to any stepwise medical procedure. Overall, experts outperformed novices in their performance on the trainer. Experts agreed that the content was acceptable, accurate, and representative.

  3. A simulation study on the focal plane detector of the LAUE project

    Science.gov (United States)

    Khalil, M.; Frontera, F.; Caroli, E.; Virgilli, E.; Valsan, V.

    2015-06-01

    The LAUE project, supported by the Italian Space Agency (ASI), is devoted to the development of a long focal length (even 20 m or longer) Laue lens for gamma ray astronomy between 80 and 600 keV. These lenses take advantage of Bragg diffraction to focus radiation onto a small spot drastically improving the signal to noise ratio as well as reducing the required size of the detector significantly. In this paper we present a Monte-Carlo simulation study with MEGALIB to optimize, for space applications, the detector size to achieve high detection efficiency, and to optimize the position resolution of the detector to reconstruct the Point Spread Function of the lens considered for the LAUE project. Then we will show simulations, using the SILVACO semiconductor simulation toolkit, on the optimized detector to estimate its capacitance per channel and depletion voltage. In all of the simulations, two materials were compared; a low density material (Silicon) and a high density material (Germanium).

  4. MixSim : An R Package for Simulating Data to Study Performance of Clustering Algorithms

    Directory of Open Access Journals (Sweden)

    Volodymyr Melnykov

    2012-11-01

    Full Text Available The R package MixSim is a new tool that allows simulating mixtures of Gaussian distributions with different levels of overlap between mixture components. Pairwise overlap, defined as a sum of two misclassification probabilities, measures the degree of interaction between components and can be readily employed to control the clustering complexity of datasets simulated from mixtures. These datasets can then be used for systematic performance investigation of clustering and finite mixture modeling algorithms. Among other capabilities of MixSim, there are computing the exact overlap for Gaussian mixtures, simulating Gaussian and non-Gaussian data, simulating outliers and noise variables, calculating various measures of agreement between two partitionings, and constructing parallel distribution plots for the graphical display of finite mixture models. All features of the package are illustrated in great detail. The utility of the package is highlighted through a small comparison study of several popular clustering algorithms.

  5. Comparative Study of Algorithms for the Numerical Simulation of Lattice QCD

    International Nuclear Information System (INIS)

    Luz, Fernando H. P.; Mendes, Tereza

    2010-01-01

    Large-scale numerical simulations are the prime method for a nonperturbative study of QCD from first principles. Although the lattice simulation of the pure-gauge (or quenched-QCD) case may be performed very efficiently on parallel machines, there are several additional difficulties in the simulation of the full-QCD case, i.e. when dynamical quark effects are taken into account. We discuss the main aspects of full-QCD simulations, describing the most common algorithms. We present a comparative analysis of performance for two versions of the hybrid Monte Carlo method (the so-called R and RHMC algorithms), as provided in the MILC software package. We consider two degenerate flavors of light quarks in the staggered formulation, having in mind the case of finite-temperature QCD.

  6. Study on Photon Transport Problem Based on the Platform of Molecular Optical Simulation Environment

    Science.gov (United States)

    Peng, Kuan; Gao, Xinbo; Liang, Jimin; Qu, Xiaochao; Ren, Nunu; Chen, Xueli; Ma, Bin; Tian, Jie

    2010-01-01

    As an important molecular imaging modality, optical imaging has attracted increasing attention in the recent years. Since the physical experiment is usually complicated and expensive, research methods based on simulation platforms have obtained extensive attention. We developed a simulation platform named Molecular Optical Simulation Environment (MOSE) to simulate photon transport in both biological tissues and free space for optical imaging based on noncontact measurement. In this platform, Monte Carlo (MC) method and the hybrid radiosity-radiance theorem are used to simulate photon transport in biological tissues and free space, respectively, so both contact and noncontact measurement modes of optical imaging can be simulated properly. In addition, a parallelization strategy for MC method is employed to improve the computational efficiency. In this paper, we study the photon transport problems in both biological tissues and free space using MOSE. The results are compared with Tracepro, simplified spherical harmonics method (S P n), and physical measurement to verify the performance of our study method on both accuracy and efficiency. PMID:20445737

  7. Study on Photon Transport Problem Based on the Platform of Molecular Optical Simulation Environment

    Directory of Open Access Journals (Sweden)

    Kuan Peng

    2010-01-01

    Full Text Available As an important molecular imaging modality, optical imaging has attracted increasing attention in the recent years. Since the physical experiment is usually complicated and expensive, research methods based on simulation platforms have obtained extensive attention. We developed a simulation platform named Molecular Optical Simulation Environment (MOSE to simulate photon transport in both biological tissues and free space for optical imaging based on noncontact measurement. In this platform, Monte Carlo (MC method and the hybrid radiosity-radiance theorem are used to simulate photon transport in biological tissues and free space, respectively, so both contact and noncontact measurement modes of optical imaging can be simulated properly. In addition, a parallelization strategy for MC method is employed to improve the computational efficiency. In this paper, we study the photon transport problems in both biological tissues and free space using MOSE. The results are compared with Tracepro, simplified spherical harmonics method (SPn, and physical measurement to verify the performance of our study method on both accuracy and efficiency.

  8. Study on photon transport problem based on the platform of molecular optical simulation environment.

    Science.gov (United States)

    Peng, Kuan; Gao, Xinbo; Liang, Jimin; Qu, Xiaochao; Ren, Nunu; Chen, Xueli; Ma, Bin; Tian, Jie

    2010-01-01

    As an important molecular imaging modality, optical imaging has attracted increasing attention in the recent years. Since the physical experiment is usually complicated and expensive, research methods based on simulation platforms have obtained extensive attention. We developed a simulation platform named Molecular Optical Simulation Environment (MOSE) to simulate photon transport in both biological tissues and free space for optical imaging based on noncontact measurement. In this platform, Monte Carlo (MC) method and the hybrid radiosity-radiance theorem are used to simulate photon transport in biological tissues and free space, respectively, so both contact and noncontact measurement modes of optical imaging can be simulated properly. In addition, a parallelization strategy for MC method is employed to improve the computational efficiency. In this paper, we study the photon transport problems in both biological tissues and free space using MOSE. The results are compared with Tracepro, simplified spherical harmonics method (SP(n)), and physical measurement to verify the performance of our study method on both accuracy and efficiency.

  9. Organizational culture shapes the adoption and incorporation of simulation into nursing curricula: a grounded theory study.

    Science.gov (United States)

    Taplay, Karyn; Jack, Susan M; Baxter, Pamela; Eva, Kevin; Martin, Lynn

    2014-01-01

    Purpose. To create a substantive mid-range theory explaining how the organizational cultures of undergraduate nursing programs shape the adoption and incorporation of mid-to high-level technical fidelity simulators as a teaching strategy within curricula. Method. A constructivist grounded theory was used to guide this study which was conducted in Ontario, Canada, during 2011-12. Semistructured interviews (n = 43) with participants that included nursing administrators, nursing faculty, and simulation leaders across multiple programs (n = 13) informed this study. Additionally, key documents (n = 67) were reviewed. Purposeful and theoretical sampling was used and data were collected and analyzed simultaneously. Data were compared among and between sites. Findings. The organizational elements that shape simulation in nursing (OESSN) model depicts five key organizational factors at the nursing program level that shaped the adoption and incorporation of simulation: (1) leaders working in tandem, (2) information exchange, (3) physical locale, (4) shared motivators, and (5) scaffolding to manage change. Conclusions. The OESSN model provides an explanation of the organizational factors that contributed to the adoption and incorporation of simulation into nursing curricula. Nursing programs that use the OESSN model may experience a more rapid or broad uptake of simulation when organizational factors that impact adoption and incorporation are considered and planned for.

  10. Digitalized design of extraforaminal lumbar interbody fusion: a computer-based simulation and cadaveric study.

    Directory of Open Access Journals (Sweden)

    Mingjie Yang

    Full Text Available PURPOSE: This study aims to investigate the feasibility of a novel lumbar approach named extraforaminal lumbar interbody fusion (ELIF, a newly emerging minimally invasive technique for treating degenerative lumbar disorders, using a digitalized simulation and a cadaveric study. METHODS: The ELIF surgical procedure was simulated using the Mimics surgical simulator and included dissection of the superior articular process, dilation of the vertebral foramen, and placement of pedicle screws and a cage. ELIF anatomical measures were documented using a digitalized technique and subsequently validated on fresh cadavers. RESULTS: The use of the Mimics allowed for the vivid simulation of ELIF surgical procedures, while the cadaveric study proved the feasibility of this novel approach. ELIF had a relatively lateral access approach that was located 8-9 cm lateral to the median line with an access depth of approximately 9 cm through the intermuscular space. Dissection of the superior articular processes could fully expose the target intervertebral discs and facilitate a more inclined placement of the pedicle screws and cage with robust enhancement. CONCLUSIONS: According to the computer-based simulation and cadaveric study, it is feasible to perform ELIF. Further research including biomechanical study is needed to prove ELIF has a superior ability to preserve the posterior tension bands of the spinal column, with similar effects on spinal decompression, fixation, and fusion, and if it can enhance post-fusion spinal stability and expedites postoperative recovery.

  11. Digitalized design of extraforaminal lumbar interbody fusion: a computer-based simulation and cadaveric study.

    Science.gov (United States)

    Yang, Mingjie; Zeng, Cheng; Guo, Song; Pan, Jie; Han, Yingchao; Li, Zeqing; Li, Lijun; Tan, Jun

    2014-01-01

    This study aims to investigate the feasibility of a novel lumbar approach named extraforaminal lumbar interbody fusion (ELIF), a newly emerging minimally invasive technique for treating degenerative lumbar disorders, using a digitalized simulation and a cadaveric study. The ELIF surgical procedure was simulated using the Mimics surgical simulator and included dissection of the superior articular process, dilation of the vertebral foramen, and placement of pedicle screws and a cage. ELIF anatomical measures were documented using a digitalized technique and subsequently validated on fresh cadavers. The use of the Mimics allowed for the vivid simulation of ELIF surgical procedures, while the cadaveric study proved the feasibility of this novel approach. ELIF had a relatively lateral access approach that was located 8-9 cm lateral to the median line with an access depth of approximately 9 cm through the intermuscular space. Dissection of the superior articular processes could fully expose the target intervertebral discs and facilitate a more inclined placement of the pedicle screws and cage with robust enhancement. According to the computer-based simulation and cadaveric study, it is feasible to perform ELIF. Further research including biomechanical study is needed to prove ELIF has a superior ability to preserve the posterior tension bands of the spinal column, with similar effects on spinal decompression, fixation, and fusion, and if it can enhance post-fusion spinal stability and expedites postoperative recovery.

  12. Post-processing of Monte Carlo simulations for rapid BNCT source optimization studies

    International Nuclear Information System (INIS)

    Bleuel, D.L.; Chu, W.T.; Donahue, R.J.; Ludewigt, B.A.; Vujic, J.

    2000-01-01

    A great advantage of some neutron sources, such as accelerator-produced sources, is that they can be tuned to produce different spectra. Unfortunately, optimization studies are often time-consuming and difficult, as they require a lengthy Monte Carlo simulation for each source. When multiple characteristics, such as energy, angle, and spatial distribution of a neutron beam are allowed to vary, an overwhelming number of simulations may be required. Many optimization studies, therefore, suffer from a small number of datapoints, restrictive treatment conditions, or poor statistics. By scoring pertinent information from every particle tally in a Monte Carlo simulation, then applying appropriate source variable weight factors in a post-processing algorithm, a single simulation can be used to model any number of multiple sources. Through this method, the response to a new source can be modeled in minutes or seconds, rather than hours or days, allowing for the analysis of truly variable source conditions of much greater resolution than is normally possible when a new simulation must be run for each datapoint in a study. This method has been benchmarked and used to recreate optimization studies in a small fraction of the time spent in the original studies

  13. Post-processing of Monte Carlo simulations for rapid BNCT source optimization studies

    International Nuclear Information System (INIS)

    Bleuel, D.L.; Chu, W.T.; Donahue, R.J.; Ludewigt, B.A.; Vujic, J.

    2000-01-01

    A great advantage of some neutron sources, such as accelerator-produced sources, is that they can be tuned to produce different spectra. Unfortunately, optimization studies are often time-consuming and difficult, as they require a lengthy Monte Carlo simulation for each source. When multiple characteristics, such as energy, angle, and spatial distribution of a neutron beam are allowed to vary, an overwhelming number of simulations may be required. Many optimization studies, therefore, suffer from a small number of data points, restrictive treatment conditions, or poor statistics. By scoring pertinent information from every particle tally in a Monte Carlo simulation, then applying appropriate source variable weight factors in a post-processing algorithm; a single simulation can be used to model any number of multiple sources. Through this method, the response to a new source can be modeled in minutes or seconds, rather than hours or days, allowing for the analysis of truly variable source conditions of much greater resolution than is normally possible when a new simulation must be run for each data point in a study. This method has been benchmarked and used to recreate optimization studies in a small fraction of the time spent in the original studies. (author)

  14. 3D simulation studies of tokamak plasmas using MHD and extended-MHD models

    International Nuclear Information System (INIS)

    Park, W.; Chang, Z.; Fredrickson, E.; Fu, G.Y.; Pomphrey, N.; Sugiyama, L.E.

    1997-01-01

    The M3D (Multi-level 3D) tokamak simulation project aims at the simulation of tokamak plasmas using a multi-level tokamak code package. Several current applications using MHD and Extended-MHD models are presented; high-β disruption studies in reversed shear plasmas using the MHD level MH3D code, ω *i stabilization and nonlinear island rotation studies using the two-fluid level MH3D-T code, studies of nonlinear saturation of TAE modes using the hybrid particle/MHD level MH3D-K code, and unstructured mesh MH3D ++ code studies. In particular, three internal mode disruption mechanisms are identified from simulation results which agree well with experimental data

  15. Standardised simulation-based emergency and intensive care nursing curriculum to improve nursing students' performance during simulated resuscitation: A quasi-experimental study.

    Science.gov (United States)

    Chen, Jie; Yang, Jian; Hu, Fen; Yu, Si-Hong; Yang, Bing-Xiang; Liu, Qian; Zhu, Xiao-Ping

    2018-03-14

    Simulation-based curriculum has been demonstrated as crucial to nursing education in the development of students' critical thinking and complex clinical skills during a resuscitation simulation. Few studies have comprehensively examined the effectiveness of a standardised simulation-based emergency and intensive care nursing curriculum on the performance of students in a resuscitation simulation. To evaluate the impact of a standardised simulation-based emergency and intensive care nursing curriculum on nursing students' response time in a resuscitation simulation. Two-group, non-randomised quasi-experimental design. A simulation centre in a Chinese University School of Nursing. Third-year nursing students (N = 39) in the Emergency and Intensive Care course were divided into a control group (CG, n = 20) and an experimental group (EG, n = 19). The experimental group participated in a standardised high-technology, simulation-based emergency and intensive care nursing curriculum. The standardised simulation-based curriculum for third-year nursing students consists of three modules: disaster response, emergency care, and intensive care, which include clinical priorities (e.g. triage), basic resuscitation skills, airway/breathing management, circulation management and team work with eighteen lecture hours, six skill-practice hours and twelve simulation hours. The control group took part in the traditional curriculum. This course included the same three modules with thirty-four lecture hours and two skill-practice hours (trauma). Perceived benefits included decreased median (interquartile ranges, IQR) seconds to start compressions [CG 32 (25-75) vs. EG 20 (18-38); p  0.05] and defibrillation [CG 222 (194-254) vs. EG 221 (214-248); p > 0.05] at the beginning of the course. A simulation-based emergency and intensive care nursing curriculum was created and well received by third-year nursing students and associated with decreased response time in a

  16. Simulation studies for a high resolution time projection chamber at the international linear collider

    Energy Technology Data Exchange (ETDEWEB)

    Muennich, A.

    2007-03-26

    The International Linear Collider (ILC) is planned to be the next large accelerator. The ILC will be able to perform high precision measurements only possible at the clean environment of electron positron collisions. In order to reach this high accuracy, the requirements for the detector performance are challenging. Several detector concepts are currently under study. The understanding of the detector and its performance will be crucial to extract the desired physics results from the data. To optimise the detector design, simulation studies are needed. Simulation packages like GEANT4 allow to model the detector geometry and simulate the energy deposit in the different materials. However, the detector response taking into account the transportation of the produced charge to the readout devices and the effects ofthe readout electronics cannot be described in detail. These processes in the detector will change the measured position of the energy deposit relative to the point of origin. The determination of this detector response is the task of detailed simulation studies, which have to be carried out for each subdetector. A high resolution Time Projection Chamber (TPC) with gas amplification based on micro pattern gas detectors, is one of the options for the main tracking system at the ILC. In the present thesis a detailed simulation tool to study the performance of a TPC was developed. Its goal is to find the optimal settings to reach an excellent momentum and spatial resolution. After an introduction to the present status of particle physics and the ILC project with special focus on the TPC as central tracker, the simulation framework is presented. The basic simulation methods and implemented processes are introduced. Within this stand-alone simulation framework each electron produced by primary ionisation is transferred through the gas volume and amplified using Gas Electron Multipliers (GEMs). The output format of the simulation is identical to the raw data from a

  17. Studying distributed cognition of simulation-based team training with DiCoT.

    Science.gov (United States)

    Rybing, Jonas; Nilsson, Heléne; Jonson, Carl-Oscar; Bang, Magnus

    2016-03-01

    Health care organizations employ simulation-based team training (SBTT) to improve skill, communication and coordination in a broad range of critical care contexts. Quantitative approaches, such as team performance measurements, are predominantly used to measure SBTTs effectiveness. However, a practical evaluation method that examines how this approach supports cognition and teamwork is missing. We have applied Distributed Cognition for Teamwork (DiCoT), a method for analysing cognition and collaboration aspects of work settings, with the purpose of assessing the methodology's usefulness for evaluating SBTTs. In a case study, we observed and analysed four Emergo Train System® simulation exercises where medical professionals trained emergency response routines. The study suggests that DiCoT is an applicable and learnable tool for determining key distributed cognition attributes of SBTTs that are of importance for the simulation validity of training environments. Moreover, we discuss and exemplify how DiCoT supports design of SBTTs with a focus on transfer and validity characteristics. Practitioner Summary: In this study, we have evaluated a method to assess simulation-based team training environments from a cognitive ergonomics perspective. Using a case study, we analysed Distributed Cognition for Teamwork (DiCoT) by applying it to the Emergo Train System®. We conclude that DiCoT is useful for SBTT evaluation and simulator (re)design.

  18. A simulator study of the combined effects of alcohol and marihuana on driving behavior--phase II

    Science.gov (United States)

    1983-02-01

    Author's abstract: The study described in this report investigated the effects of alcohol and marihuana, alone and in combination, on driver performance and behavior in a fully interactive driving simulator. The simulator provided the driver a comple...

  19. Magnetic force microscopy and simulation studies on Co 50 Fe 50 ...

    Indian Academy of Sciences (India)

    We studied the magnetization reversal mechanism of single-layered Co50Fe50 nanomagnets by measuring the magnetization reversal and using the micromagnetic simulations. The magnetization reversal strongly depends on the thickness of the nanomagnets. In the remanent state, the magnetic force microscopy studies ...

  20. Simulating clinical studies of the glucoregulatory system: in vivo meets in silico

    DEFF Research Database (Denmark)

    Wendt, Sabrina Lyngbye; Ranjan, Ajenthen; Møller, Jan Kloppenborg

    metabolism at varying ambient insulin levels. The report compares in vivo and in silico results head-to-head, and discusses similarities and differences. We design and simulate simple studies to emphasize the implications of some glucoregulatory dynamics which are ignored in most previous clinical studies...

  1. Simulative study on dose distribution of 103Pd stent in blood-vessel

    International Nuclear Information System (INIS)

    Yuan Shuyu; Dai Guangfu; Xu Zhiyong; Sun Fuyin; Xu Shuhe; Ma Fengwu

    2003-01-01

    Objective: To evaluate the dose distribution of 103 Pd stent in the blood-vessel. Methods: Simulative study on dose distribution of endovascular 103 Pd stent was conducted with thermoluminescence dosimeter. The vessel wall was substituted by muscle equivalent material in this simulative study. Results: When radioactivity of the study 103 Pd stent was 9.8 MBq the absorbed dose from the stent surface by muscle equivalent material was 9.8 Gy at 17 d (the half-life period of 103 Pd). The radioactivity of 103 Pd stent surface rapidly attenuated over the radial distance. 80% of the radioactivity at the area that was radially 0.4 mm apart from the stent surface was absorbed by the simulative blood-vessel wall. Conclusion: Endovascular 103 Pd stent does not exert significant injury on the surrounding organs or tissues

  2. Study of Monte Carlo Simulation Method for Methane Phase Diagram Prediction using Two Different Potential Models

    KAUST Repository

    Kadoura, Ahmad

    2011-06-06

    Lennard‐Jones (L‐J) and Buckingham exponential‐6 (exp‐6) potential models were used to produce isotherms for methane at temperatures below and above critical one. Molecular simulation approach, particularly Monte Carlo simulations, were employed to create these isotherms working with both canonical and Gibbs ensembles. Experiments in canonical ensemble with each model were conducted to estimate pressures at a range of temperatures above methane critical temperature. Results were collected and compared to experimental data existing in literature; both models showed an elegant agreement with the experimental data. In parallel, experiments below critical temperature were run in Gibbs ensemble using L‐J model only. Upon comparing results with experimental ones, a good fit was obtained with small deviations. The work was further developed by adding some statistical studies in order to achieve better understanding and interpretation to the estimated quantities by the simulation. Methane phase diagrams were successfully reproduced by an efficient molecular simulation technique with different potential models. This relatively simple demonstration shows how powerful molecular simulation methods could be, hence further applications on more complicated systems are considered. Prediction of phase behavior of elemental sulfur in sour natural gases has been an interesting and challenging field in oil and gas industry. Determination of elemental sulfur solubility conditions helps avoiding all kinds of problems caused by its dissolution in gas production and transportation processes. For this purpose, further enhancement to the methods used is to be considered in order to successfully simulate elemental sulfur phase behavior in sour natural gases mixtures.

  3. Study on simulation methods of atrium building cooling load in hot and humid regions

    Energy Technology Data Exchange (ETDEWEB)

    Pan, Yiqun; Li, Yuming; Huang, Zhizhong [Institute of Building Performance and Technology, Sino-German College of Applied Sciences, Tongji University, 1239 Siping Road, Shanghai 200092 (China); Wu, Gang [Weldtech Technology (Shanghai) Co. Ltd. (China)

    2010-10-15

    In recent years, highly glazed atria are popular because of their architectural aesthetics and advantage of introducing daylight into inside. However, cooling load estimation of such atrium buildings is difficult due to complex thermal phenomena that occur in the atrium space. The study aims to find out a simplified method of estimating cooling loads through simulations for various types of atria in hot and humid regions. Atrium buildings are divided into different types. For every type of atrium buildings, both CFD and energy models are developed. A standard method versus the simplified one is proposed to simulate cooling load of atria in EnergyPlus based on different room air temperature patterns as a result from CFD simulation. It incorporates CFD results as input into non-dimensional height room air models in EnergyPlus, and the simulation results are defined as a baseline model in order to compare with the results from the simplified method for every category of atrium buildings. In order to further validate the simplified method an actual atrium office building is tested on site in a typical summer day and measured results are compared with simulation results using the simplified methods. Finally, appropriate methods of simulating different types of atrium buildings are proposed. (author)

  4. Agent Behavior-Based Simulation Study on Mass Collaborative Product Development Process

    Directory of Open Access Journals (Sweden)

    Shuo Zhang

    2015-01-01

    Full Text Available Mass collaborative product development (MCPD benefits people by high innovation products with lower cost and shorter lead time due to quick development of group innovation, Internet-based customization, and prototype manufacturing. Simulation is an effective way to study the evolution process and therefore to guarantee the success of MCPD. In this paper, an agent behavior-based simulation approach of MCPD is developed, which models the MCPD process as the interactive process of design agents and the environment objects based on Complex Adaptive System (CAS theory. Next, the structure model of design agent is proposed, and the modification and collaboration behaviors are described. Third, the agent behavior-based simulation flow of MCPD is designed. At last, simulation experiments are carried out based on an engineering case of mobile phone design. The experiment results show the following: (1 the community scale has significant influence on MCPD process; (2 the simulation process can explicitly represent the modification and collaboration behaviors of design agents; (3 the community evolution process can be observed and analyzed dynamically based on simulation data.

  5. Simulation-Based Approach for Studying the Balancing of Local Smart Grids with Electric Vehicle Batteries

    Directory of Open Access Journals (Sweden)

    Juhani Latvakoski

    2015-07-01

    Full Text Available Modern society is facing great challenges due to pollution and increased carbon dioxide (CO2 emissions. As part of solving these challenges, the use of renewable energy sources and electric vehicles (EVs is rapidly increasing. However, increased dynamics have triggered problems in balancing energy supply and consumption demand in the power systems. The resulting uncertainty and unpredictability of energy production, consumption, and management of peak loads has caused an increase in costs for energy market actors. Therefore, the means for studying the balancing of local smart grids with EVs is a starting point for this paper. The main contribution is a simulation-based approach which was developed to enable the study of the balancing of local distribution grids with EV batteries in a cost-efficient manner. The simulation-based approach is applied to enable the execution of a distributed system with the simulation of a local distribution grid, including a number of charging stations and EVs. A simulation system has been constructed to support the simulation-based approach. The evaluation has been carried out by executing the scenario related to balancing local distribution grids with EV batteries in a step-by-step manner. The evaluation results indicate that the simulation-based approach is able to facilitate the evaluation of smart grid– and EV-related communication protocols, control algorithms for charging, and functionalities of local distribution grids as part of a complex, critical cyber-physical system. In addition, the simulation system is able to incorporate advanced methods for monitoring, controlling, tracking, and modeling behavior. The simulation model of the local distribution grid can be executed with the smart control of charging and discharging powers of the EVs according to the load situation in the local distribution grid. The resulting simulation system can be applied to the study of balancing local smart grids with EV

  6. A study on optimization of hybrid drive train using Advanced Vehicle Simulator (ADVISOR)

    Energy Technology Data Exchange (ETDEWEB)

    Same, Adam; Stipe, Alex; Grossman, David; Park, Jae Wan [Department of Mechanical and Aeronautical Engineering, University of California, Davis, One Shields Ave, Davis, CA 95616 (United States)

    2010-10-01

    This study investigates the advantages and disadvantages of three hybrid drive train configurations: series, parallel, and ''through-the-ground'' parallel. Power flow simulations are conducted with the MATLAB/Simulink-based software ADVISOR. These simulations are then applied in an application for the UC Davis SAE Formula Hybrid vehicle. ADVISOR performs simulation calculations for vehicle position using a combined backward/forward method. These simulations are used to study how efficiency and agility are affected by the motor, fuel converter, and hybrid configuration. Three different vehicle models are developed to optimize the drive train of a vehicle for three stages of the SAE Formula Hybrid competition: autocross, endurance, and acceleration. Input cycles are created based on rough estimates of track geometry. The output from these ADVISOR simulations is a series of plots of velocity profile and energy storage State of Charge that provide a good estimate of how the Formula Hybrid vehicle will perform on the given course. The most noticeable discrepancy between the input cycle and the actual velocity profile of the vehicle occurs during deceleration. A weighted ranking system is developed to organize the simulation results and to determine the best drive train configuration for the Formula Hybrid vehicle. Results show that the through-the-ground parallel configuration with front-mounted motors achieves an optimal balance of efficiency, simplicity, and cost. ADVISOR is proven to be a useful tool for vehicle power train design for the SAE Formula Hybrid competition. This vehicle model based on ADVISOR simulation is applicable to various studies concerning performance and efficiency of hybrid drive trains. (author)

  7. A Study on Evaluation of Training Program for MCR Operators of SMART Simulator

    Energy Technology Data Exchange (ETDEWEB)

    Park, Hyun Jun; Lee, Joon Ku; Jeong, Kwang Il [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of)

    2015-10-15

    It is important to develop a training program by simulators in main control room of nuclear power plants because there is no an operation expert and no operating experience in the pre-construction phase of nuclear power plants. It is also necessary to develop a training program and its evaluation method taking human error into account. The purpose of this study is developing evaluation model of simulators. In a training program, once training requirements are selected, evaluation of training is as important as its implementation. Training effectiveness is available value in a simulator-based environment. The main control room of SMART (System-integrated Modular Advanced ReacTor) is consist of workstation, visual display units such as LDP and FPD based on digital systems. Cognitive behaviors of a high level are required to operators in these man-machine interface system (MMIS). Therefore, it is essential to identify training requirements and to develop its evaluation model. Virtual Environments such as a simulator have utilized by a lot of industries and companies for training and accident prevention. Simulators have three primary benefits. The first is that training by simulators is less expensive than those in real environment. The second is that simulators enable safety enhancement using systematic training program. The third is that simulators provide a preliminary to prevent human error. It is significant to apply TER, TCR, TCE in evaluation of training effect. It is expected that these could be applied to revise training criteria and enable to consider efficiency in terms of cost and benefit.

  8. A Study on Evaluation of Training Program for MCR Operators of SMART Simulator

    International Nuclear Information System (INIS)

    Park, Hyun Jun; Lee, Joon Ku; Jeong, Kwang Il

    2015-01-01

    It is important to develop a training program by simulators in main control room of nuclear power plants because there is no an operation expert and no operating experience in the pre-construction phase of nuclear power plants. It is also necessary to develop a training program and its evaluation method taking human error into account. The purpose of this study is developing evaluation model of simulators. In a training program, once training requirements are selected, evaluation of training is as important as its implementation. Training effectiveness is available value in a simulator-based environment. The main control room of SMART (System-integrated Modular Advanced ReacTor) is consist of workstation, visual display units such as LDP and FPD based on digital systems. Cognitive behaviors of a high level are required to operators in these man-machine interface system (MMIS). Therefore, it is essential to identify training requirements and to develop its evaluation model. Virtual Environments such as a simulator have utilized by a lot of industries and companies for training and accident prevention. Simulators have three primary benefits. The first is that training by simulators is less expensive than those in real environment. The second is that simulators enable safety enhancement using systematic training program. The third is that simulators provide a preliminary to prevent human error. It is significant to apply TER, TCR, TCE in evaluation of training effect. It is expected that these could be applied to revise training criteria and enable to consider efficiency in terms of cost and benefit

  9. Predictive validity of driving-simulator assessments following traumatic brain injury: a preliminary study.

    Science.gov (United States)

    Lew, Henry L; Poole, John H; Lee, Eun Ha; Jaffe, David L; Huang, Hsiu-Chen; Brodd, Edward

    2005-03-01

    To evaluate whether driving simulator and road test evaluations can predict long-term driving performance, we conducted a prospective study on 11 patients with moderate to severe traumatic brain injury. Sixteen healthy subjects were also tested to provide normative values on the simulator at baseline. At their initial evaluation (time-1), subjects' driving skills were measured during a 30-minute simulator trial using an automated 12-measure Simulator Performance Index (SPI), while a trained observer also rated their performance using a Driving Performance Inventory (DPI). In addition, patients were evaluated on the road by a certified driving evaluator. Ten months later (time-2), family members observed patients driving for at least 3 hours over 4 weeks and rated their driving performance using the DPI. At time-1, patients were significantly impaired on automated SPI measures of driving skill, including: speed and steering control, accidents, and vigilance to a divided-attention task. These simulator indices significantly predicted the following aspects of observed driving performance at time-2: handling of automobile controls, regulation of vehicle speed and direction, higher-order judgment and self-control, as well as a trend-level association with car accidents. Automated measures of simulator skill (SPI) were more sensitive and accurate than observational measures of simulator skill (DPI) in predicting actual driving performance. To our surprise, the road test results at time-1 showed no significant relation to driving performance at time-2. Simulator-based assessment of patients with brain injuries can provide ecologically valid measures that, in some cases, may be more sensitive than a traditional road test as predictors of long-term driving performance in the community.

  10. The process of adopting and incorporating simulation into undergraduate nursing curricula: a grounded theory study.

    Science.gov (United States)

    Taplay, Karyn; Jack, Susan M; Baxter, Pamela; Eva, Kevin; Martin, Lynn

    2015-01-01

    The aim of this study is to explain the process of adopting and incorporating simulation as a teaching strategy in undergraduate nursing programs, define uptake, and discuss potential outcomes. In many countries, simulation is increasingly adopted as a common teaching strategy. However, there is a dearth of knowledge related to the process of adoption and incorporation. We used an interpretive, constructivist approach to grounded theory to guide this research study. We conducted the study was in Ontario, Canada, during 2011-2012. Using multiple data sources, we informed the development of this theory including in-depth interviews (n = 43) and a review of key organizational documents, such as mission and vision statements (n = 67) from multiple nursing programs (n = 13). The adoption and uptake of mid- to high-fidelity simulation equipment is a multistep iterative process involving various organizational levels within the institution that entails a seven-phase process: (a) securing resources, (b) nursing leaders working in tandem, (c) getting it out of the box, (d) learning about simulation and its potential for teaching, (e) finding a fit, (f) trialing the equipment, and (g) integrating into the curriculum. These findings could assist nursing programs in Canada and internationally that wish to adopt or further incorporate simulation into their curricula and highlight potential organizational and program level outcomes. Crown Copyright © 2015. Published by Elsevier Inc. All rights reserved.

  11. The Problem of Controlling for Imperfectly Measured Confounders on Dissimilar Populations: A Database Simulation Study

    Science.gov (United States)

    Schonberger, Robert B; Gilbertsen, Todd; Dai, Feng

    2013-01-01

    Objective(s) Observational database research frequently relies on imperfect administrative markers to determine comorbid status, and it is difficult to infer to what extent the associated misclassification impacts validity in multivariable analyses. The effect that imperfect markers of disease will have on validity in situations where researchers attempt to match populations that have strong baseline health differences is underemphasized as a limitation in some otherwise high-quality observational studies. The present simulations were designed as a quantitative demonstration of the importance of this common and underappreciated issue. Design Two groups of Monte Carlo simulations were performed. The first demonstrated the degree to which controlling for a series of imperfect markers of disease between different populations taking 2 hypothetically harmless drugs would lead to spurious associations between drug assignment and mortality. The second Monte Carlo simulation applied this principle to a recent study in the field of anesthesiology that purported to show increased perioperative mortality in patients taking metoprolol versus atenolol. Setting/Participants/Interventions None. Measurements and Main Results Simulation 1: High type 1 error (ie, false positive findings of an independent association between drug assignment and mortality) was observed as sensitivity and specificity declined and as systematic differences in disease prevalence increased. Simulation 2: Propensity score matching across several imperfect markers was unlikely to eliminate important baseline health disparities in the referenced study. Conclusions In situations where large baseline health disparities exist between populations, matching on imperfect markers of disease may result in strong bias away from the null hypothesis. PMID:23962461

  12. Validation study of a computer-based open surgical trainer: SimPraxis® simulation platform

    Directory of Open Access Journals (Sweden)

    Tran LN

    2013-03-01

    Full Text Available Linh N Tran,1 Priyanka Gupta,2 Lauren H Poniatowski,2 Shaheen Alanee,3 Marc A Dall’Era,4 Robert M Sweet21Department of Internal Medicine, Loma Linda University, Loma Linda, CA, 2Department of Urology, University of Minnesota, Minneapolis, MN, 3Urology Service, Department of Surgery, Memorial Sloan-Kettering Cancer Center, New York, NY, 4Department of Urology, University of California, Davis, CA, USABackground: Technological advances have dramatically changed medical education, particularly in the era of work-hour restrictions, which increasingly highlights a need for novel methods to teach surgical skills. The purpose of this study was to evaluate the validity of a novel, computer-based, interactive, cognitive simulator for training surgeons to perform pelvic lymph node dissection (PLND.Methods: Eight prostate cancer experts evaluated the content of the simulator. Contextual aspects of the simulator were rated on a five-point Likert scale. The experts and nine first-year residents completed a simulated PLND. Time and deviations were logged, and the results were compared between experts and novices using the Mann–Whitney test.Results: Before training, 88% of the experts felt that a validated simulator would be useful for PLND training. After testing, 100% of the experts felt that it would be more useful than standard video training. Eighty-eight percent stated that they would like to see the simulator in the curriculum of residency programs and 56% thought it would be useful for accreditation purposes. The experts felt that the simulator aided in overall understanding, training indications, concepts and steps of the procedure, training how to use an assistant, and enhanced the knowledge of anatomy. Median performance times taken by experts and interns to complete a PLND procedure on the simulator were 12.62 and 23.97 minutes, respectively. Median deviation from the incorporated procedure pathway for experts was 24.5 and was 89 for novices

  13. A verification study and trend analysis of simulated boundary layer wind fields over Europe

    Energy Technology Data Exchange (ETDEWEB)

    Lindenberg, Janna

    2011-07-01

    Simulated wind fields from regional climate models (RCMs) are increasingly used as a surrogate for observations which are costly and prone to homogeneity deficiencies. Compounding the problem, a lack of reliable observations makes the validation of the simulated wind fields a non trivial exercise. Whilst the literature shows that RCMs tend to underestimate strong winds over land these investigations mainly relied on comparisons with near surface measurements and extrapolated model wind fields. In this study a new approach is proposed using measurements from high towers and a robust validation process. Tower height wind data are smoother and thus more representative of regional winds. As benefit this approach circumvents the need to extrapolate simulated wind fields. The performance of two models using different downscaling techniques is evaluated. The influence of the boundary conditions on the simulation of wind statistics is investigated. Both models demonstrate a reasonable performance over flat homogeneous terrain and deficiencies over complex terrain, such as the Upper Rhine Valley, due to a too coarse spatial resolution ({proportional_to}50 km). When the spatial resolution is increased to 10 and 20 km respectively a benefit is found for the simulation of the wind direction only. A sensitivity analysis shows major deviations of international land cover data. A time series analysis of dynamically downscaled simulations is conducted. While the annual cycle and the interannual variability are well simulated, the models are less effective at simulating small scale fluctuations and the diurnal cycle. The hypothesis that strong winds are underestimated by RCMs is supported by means of a storm analysis. Only two-thirds of the observed storms are simulated by the model using a spectral nudging approach. In addition ''False Alarms'' are simulated, which are not detected in the observations. A trend analysis over the period 1961 - 2000 is conducted

  14. A simulation study of linear coupling effects and their correction in RHIC

    International Nuclear Information System (INIS)

    Parzen, G.

    1993-01-01

    This paper describes a possible skew quadrupole correction system for linear coupling effects for the RHIC92 lattice. A simulation study has been done for this correction system. Results are given for the performance of the correction system and the required strength of the skew quadrupole corrections. The location of the correctors is discussed. For RHIC92, it appears possible to use the same 2 family correction system for all the likely choices of β*. The simulation study gives results for the residual tune splitting that remains after correction with a 2 family correction system. It also gives results for the beta functions before and after correction

  15. A study of the feasibility of statistical analysis of airport performance simulation

    Science.gov (United States)

    Myers, R. H.

    1982-01-01

    The feasibility of conducting a statistical analysis of simulation experiments to study airport capacity is investigated. First, the form of the distribution of airport capacity is studied. Since the distribution is non-Gaussian, it is important to determine the effect of this distribution on standard analysis of variance techniques and power calculations. Next, power computations are made in order to determine how economic simulation experiments would be if they are designed to detect capacity changes from condition to condition. Many of the conclusions drawn are results of Monte-Carlo techniques.

  16. Anybody can do Value at Risk: A Teaching Study using Parametric Computation and Monte Carlo Simulation

    Directory of Open Access Journals (Sweden)

    Yun Hsing Cheung

    2012-12-01

    Full Text Available The three main Value at Risk (VaR methodologies are historical, parametric and Monte Carlo Simulation.Cheung & Powell (2012, using a step-by-step teaching study, showed how a nonparametric historical VaRmodel could be constructed using Excel, thus benefitting teachers and researchers by providing them with areadily useable teaching study and an inexpensive and flexible VaR modelling option. This article extends thatwork by demonstrating how parametric and Monte Carlo Simulation VaR models can also be constructed inExcel, thus providing a total Excel modelling package encompassing all three VaR methods.

  17. Studies to mitigate difference between real data and simulation for jet tagging

    CERN Multimedia

    CERN. Geneva; Martelli, Arabella; Kieseler, Jan; Verzetti, Mauro; Stoye, Markus

    2018-01-01

    The aim of the studies presented is to improve the performance of jet flavour tagging on real data while still exploiting a simulated dataset for the learning of the main classification task. In the presentation we explore “off the shelf” domain adaptation techniques as well as customised additions to them. The latter improves the calibration of the tagger, potentially leading to smaller systematic uncertainties. The studies are performed with simplified simulations for the case of b-jet tagging. The presentation will include first results as well as discuss pitfalls that we discovered during our research.

  18. Random telegraph signal amplitudes in sub 100 nm (decanano) MOSFETs: a 3D `Atomistic' simulation study

    OpenAIRE

    Asenov, A.; Balasubramaniam, R.; Brown, A.R.; Davies, J.H.; Saini, S.

    2000-01-01

    In this paper we use 3D simulations to study the amplitudes of random telegraph signals (RTS) associated with the trapping of a single carrier in interface states in the channel of sub 100 nm (decanano) MOSFETs. Both simulations using continuous doping charge and random discrete dopants in the active region of the MOSFETs are presented. We have studied the dependence of the RTS amplitudes on the position of the trapped charge in the channel and on the device design parameters. We have observe...

  19. Flood Zoning Simulation by HEC-RAS Model (Case Study: Johor River-Kota Tinggi Region)

    OpenAIRE

    ShahiriParsa, Ahmad; Heydari, Mohammad; Sadeghian, Mohammad Sadegh; Moharrampour, Mahdi

    2015-01-01

    Flooding of rivers has caused many human and financial losses. Hence, studies and research on the nature of the river is inevitable.However, the behavior of rivers hasmany complexities and in this respect, computer models are efficient tools in order to study and simulate the behavior of rivers with the least possible cost. In this paper, one-dimensional model HEC-RAS was used to simulate the flood zoning in the Kota Tinggi district in Johor state. Implementation processes of the zoning on ca...

  20. Study on the reactivity behavior partially loaded reactor cores using SIMULATE-3

    International Nuclear Information System (INIS)

    Holzer, Robert; Zeitz, Andreas; Grimminger, Werner; Lubczyk, Tobias

    2009-01-01

    The reactor core design for the NPP Gundremmingen unit B and C is performed since several years using the validated 3D reactor core calculation program SIMULATE-3. The authors describe a special application of the program to study the reactivity for different partial core loadings. Based on the comparison with results of the program CASMO-4 the program SIMULATE-3 was validated for the calculation of partially loaded reactor cores. For the planned reactor operation in NPP Gundremmingen using new MOX fuel elements the reactivity behavior was studied with respect to the KTA-Code requirements.

  1. An evaluation of edge effects in nutritional accessibility and availability measures: a simulation study.

    Science.gov (United States)

    Van Meter, Emily M; Lawson, Andrew B; Colabianchi, Natalie; Nichols, Michele; Hibbert, James; Porter, Dwayne E; Liese, Angela D

    2010-07-27

    This paper addresses the statistical use of accessibility and availability indices and the effect of study boundaries on these measures. The measures are evaluated via an extensive simulation based on cluster models for local outlet density. We define outlet to mean either food retail store (convenience store, supermarket, gas station) or restaurant (limited service or full service restaurants). We designed a simulation whereby a cluster outlet model is assumed in a large study window and an internal subset of that window is constructed. We performed simulations on various criteria including one scenario representing an urban area with 2000 outlets as well as a non-urban area simulated with only 300 outlets. A comparison is made between estimates obtained with the full study area and estimates using only the subset area. This allows the study of the effect of edge censoring on accessibility measures. The results suggest that considerable bias is found at the edges of study regions in particular for accessibility measures. Edge effects are smaller for availability measures (when not smoothed) and also for short range accessibility It is recommended that any study utilizing these measures should correct for edge effects. The use of edge correction via guard areas is recommended and the avoidance of large range distance-based accessibility measures is also proposed.

  2. An evaluation of edge effects in nutritional accessibility and availability measures: a simulation study

    Directory of Open Access Journals (Sweden)

    Porter Dwayne E

    2010-07-01

    Full Text Available Abstract Background This paper addresses the statistical use of accessibility and availability indices and the effect of study boundaries on these measures. The measures are evaluated via an extensive simulation based on cluster models for local outlet density. We define outlet to mean either food retail store (convenience store, supermarket, gas station or restaurant (limited service or full service restaurants. We designed a simulation whereby a cluster outlet model is assumed in a large study window and an internal subset of that window is constructed. We performed simulations on various criteria including one scenario representing an urban area with 2000 outlets as well as a non-urban area simulated with only 300 outlets. A comparison is made between estimates obtained with the full study area and estimates using only the subset area. This allows the study of the effect of edge censoring on accessibility measures. Results The results suggest that considerable bias is found at the edges of study regions in particular for accessibility measures. Edge effects are smaller for availability measures (when not smoothed and also for short range accessibility Conclusions It is recommended that any study utilizing these measures should correct for edge effects. The use of edge correction via guard areas is recommended and the avoidance of large range distance-based accessibility measures is also proposed.

  3. Development of simulator for studying formation process of crustal structure. 1; Chikaku kozo keisei simulator no kaihatsu. 1

    Energy Technology Data Exchange (ETDEWEB)

    Matsushima, J. [The University of Tokyo, Tokyo (Japan). Faculty of Engineering; Murakami, Y.; Okubo, Y.; Matsubayashi, O.; Tanaka, A.; Nakajima, Y.; Morijiri, R. [Geological Survey of Japan, Tsukuba (Japan); Rokugawa, S. [The University of Tokyo, Tokyo (Japan)

    1997-05-27

    The purpose of this study is to combine seismic activity and volcanic activity by reproducing the formation process of the crustal structure from a physical viewpoint or developing as its extension a numerical simulator which can predict the future. The phenomenon to which attention is especially paid at present is a relation between the dynamic process and the thermal process in the domain including the crust or the upper mantle. Namely, to elucidate the formation process of the crust structure, diastrophism also including seismic activity, igneous activity, etc., it is important to evaluate effects of the behavior of heat supplied from the deep on the dynamic process. In the finite element method, it is not easy to make the effect of gravity reflect to the calculation for boundary conditions. Accordingly, it is general to pay attention to stress difference, considering that stress by gravity is in proportion to static rock pressure stress. Further, to realize interaction between the thermal process and the dynamic process, effects of thermal stress are expressed combining the heat conducting analysis and the plastic flow analysis. 3 refs., 7 figs.

  4. 42: An Open-Source Simulation Tool for Study and Design of Spacecraft Attitude Control Systems

    Science.gov (United States)

    Stoneking, Eric

    2018-01-01

    Simulation is an important tool in the analysis and design of spacecraft attitude control systems. The speaker will discuss the simulation tool, called simply 42, that he has developed over the years to support his own work as an engineer in the Attitude Control Systems Engineering Branch at NASA Goddard Space Flight Center. 42 was intended from the outset to be high-fidelity and powerful, but also fast and easy to use. 42 is publicly available as open source since 2014. The speaker will describe some of 42's models and features, and discuss its applicability to studies ranging from early concept studies through the design cycle, integration, and operations. He will outline 42's architecture and share some thoughts on simulation development as a long-term project.

  5. Using a Radiofrequency Identification System for Improving the Patient Discharge Process: A Simulation Study.

    Science.gov (United States)

    Shim, Sung J; Kumar, Arun; Jiao, Roger

    2016-01-01

    A hospital is considering deploying a radiofrequency identification (RFID) system and setting up a new "discharge lounge" to improve the patient discharge process. This study uses computer simulation to model and compare the current process and the new process, and it assesses the impact of the RFID system and the discharge lounge on the process in terms of resource utilization and time taken in the process. The simulation results regarding resource utilization suggest that the RFID system can slightly relieve the burden on all resources, whereas the RFID system and the discharge lounge together can significantly mitigate the nurses' tasks. The simulation results in terms of the time taken demonstrate that the RFID system can shorten patient wait times, staff busy times, and bed occupation times. The results of the study could prove helpful to others who are considering the use of an RFID system in the patient discharge process in hospitals or similar processes.

  6. Effect of Single-Electron Interface Trapping in Decanano MOSFETs: A 3D Atomistic Simulation Study

    Science.gov (United States)

    Asenov, Asen; Balasubramaniam, R.; Brown, A. R.; Davies, J. H.

    2000-01-01

    We study the effect of trapping/detrapping of a single-electron in interface states in the channel of n-type MOSFETs with decanano dimensions using 3D atomistic simulation techniques. In order to highlight the basic dependencies, the simulations are carried out initially assuming continuous doping charge, and discrete localized charge only for the trapped electron. The dependence of the random telegraph signal (RTS) amplitudes on the device dimensions and on the position of the trapped charge in the channel are studied in detail. Later, in full-scale, atomistic simulations assuming discrete charge for both randomly placed dopants and the trapped electron, we highlight the importance of current percolation and of traps with strategic position where the trapped electron blocks a dominant current path.

  7. A simulation study of interface mixing during ion-assisted deposition

    International Nuclear Information System (INIS)

    Wenzhi Li; Fuzhai Cui; Yi Liao; Hengde Li

    1990-01-01

    Ion-beam assisted deposition (IAD) can produce strong film to substrate adhesion. The adhesion depends heavily on atom mixing near the interface. In order to study the dependence of the width of the mixed interface on the experimental parameters, a Monte Carlo study has been made using the dynamic simulation code TCIS-6. The simulation mode and calculational procedure are described. Simulation calculations indicate that the mixing increases with the bombarding energies and a saturation width appears at high energies. There is a strong relationship between the amount of mixing and the ion-to-atom arrival ratio. Some comparisons of the calculations with experimental data in the literature are also presented. (author)

  8. Toward high-efficiency and detailed Monte Carlo simulation study of the granular flow spallation target

    Science.gov (United States)

    Cai, Han-Jie; Zhang, Zhi-Lei; Fu, Fen; Li, Jian-Yang; Zhang, Xun-Chao; Zhang, Ya-Ling; Yan, Xue-Song; Lin, Ping; Xv, Jian-Ya; Yang, Lei

    2018-02-01

    The dense granular flow spallation target is a new target concept chosen for the Accelerator-Driven Subcritical (ADS) project in China. For the R&D of this kind of target concept, a dedicated Monte Carlo (MC) program named GMT was developed to perform the simulation study of the beam-target interaction. Owing to the complexities of the target geometry, the computational cost of the MC simulation of particle tracks is highly expensive. Thus, improvement of computational efficiency will be essential for the detailed MC simulation studies of the dense granular target. Here we present the special design of the GMT program and its high efficiency performance. In addition, the speedup potential of the GPU-accelerated spallation models is discussed.

  9. Study on computer-aided simulation procedure for multicomponent separating cascade

    International Nuclear Information System (INIS)

    Kinoshita, Masahiro

    1982-11-01

    The present report reviews the author's study on the computer-aided simulation procedure for a multicomponent separating cascade. As a conclusion, two very powerful simulation procedures have been developed for cascades composed of separating elements whose separation factors are very large. They are applicable in cases where interstage flow rates are input variables for the calculation and stage separation factors are given either as constants or as functions of compositions of the up and down streams. As an application of the new procedure, a computer-aided simulation study has been performed for hydrogen isotope separating cascades by porous membrane method. A cascade system configuration is developed and pertinent design specifications are determined in an example case of the feed conditions and separation requirements. (author)

  10. A simulation study of active feedback supression of dynamic response in helicopter rotor blades

    Science.gov (United States)

    Kana, D. D.; Bessey, R. L.; Dodge, F. T.

    1975-01-01

    A parameter study is presented for active feedback control applied to a helicopter rotor blade during forward flight. The study was performed on an electromechanical apparatus which included a mechanical model rotor blade and electronic analog simulation of interaction between blade deflections and aerodynamic loading. Blade response parameters were obtained for simulated vortex impinging at the blade tip at one pulse per revolution, and for a pulse which traveled from the blade tip toward its root. Results show that the response in a 1 - 10-per-rev frequency band is diminished by the feedback action, but at the same time responses at frequencies above 10-per-rev become increasingly more prominent with increased feedback amplitude, and can even lead to instability at certain levels. It appears that the latter behavior results from limitations of the laboratory simulation apparatus, rather than genuine potential behavior for a prototype helicopter.

  11. Statistical Analysis of Large Simulated Yield Datasets for Studying Climate Effects

    Science.gov (United States)

    Makowski, David; Asseng, Senthold; Ewert, Frank; Bassu, Simona; Durand, Jean-Louis; Martre, Pierre; Adam, Myriam; Aggarwal, Pramod K.; Angulo, Carlos; Baron, Chritian; hide

    2015-01-01

    Many studies have been carried out during the last decade to study the effect of climate change on crop yields and other key crop characteristics. In these studies, one or several crop models were used to simulate crop growth and development for different climate scenarios that correspond to different projections of atmospheric CO2 concentration, temperature, and rainfall changes (Semenov et al., 1996; Tubiello and Ewert, 2002; White et al., 2011). The Agricultural Model Intercomparison and Improvement Project (AgMIP; Rosenzweig et al., 2013) builds on these studies with the goal of using an ensemble of multiple crop models in order to assess effects of climate change scenarios for several crops in contrasting environments. These studies generate large datasets, including thousands of simulated crop yield data. They include series of yield values obtained by combining several crop models with different climate scenarios that are defined by several climatic variables (temperature, CO2, rainfall, etc.). Such datasets potentially provide useful information on the possible effects of different climate change scenarios on crop yields. However, it is sometimes difficult to analyze these datasets and to summarize them in a useful way due to their structural complexity; simulated yield data can differ among contrasting climate scenarios, sites, and crop models. Another issue is that it is not straightforward to extrapolate the results obtained for the scenarios to alternative climate change scenarios not initially included in the simulation protocols. Additional dynamic crop model simulations for new climate change scenarios are an option but this approach is costly, especially when a large number of crop models are used to generate the simulated data, as in AgMIP. Statistical models have been used to analyze responses of measured yield data to climate variables in past studies (Lobell et al., 2011), but the use of a statistical model to analyze yields simulated by complex

  12. Application of geostatistical simulation to compile seismotectonic provinces based on earthquake databases (case study: Iran)

    Science.gov (United States)

    Jalali, Mohammad; Ramazi, Hamidreza

    2018-04-01

    This article is devoted to application of a simulation algorithm based on geostatistical methods to compile and update seismotectonic provinces in which Iran has been chosen as a case study. Traditionally, tectonic maps together with seismological data and information (e.g., earthquake catalogues, earthquake mechanism, and microseismic data) have been used to update seismotectonic provinces. In many cases, incomplete earthquake catalogues are one of the important challenges in this procedure. To overcome this problem, a geostatistical simulation algorithm, turning band simulation, TBSIM, was applied to make a synthetic data to improve incomplete earthquake catalogues. Then, the synthetic data was added to the traditional information to study the seismicity homogeneity and classify the areas according to tectonic and seismic properties to update seismotectonic provinces. In this paper, (i) different magnitude types in the studied catalogues have been homogenized to moment magnitude (Mw), and earthquake declustering was then carried out to remove aftershocks and foreshocks; (ii) time normalization method was introduced to decrease the uncertainty in a temporal domain prior to start the simulation procedure; (iii) variography has been carried out in each subregion to study spatial regressions (e.g., west-southwestern area showed a spatial regression from 0.4 to 1.4 decimal degrees; the maximum range identified in the azimuth of 135 ± 10); (iv) TBSIM algorithm was then applied to make simulated events which gave rise to make 68,800 synthetic events according to the spatial regression found in several directions; (v) simulated events (i.e., magnitudes) were classified based on their intensity in ArcGIS packages and homogenous seismic zones have been determined. Finally, according to the synthetic data, tectonic features, and actual earthquake catalogues, 17 seismotectonic provinces were introduced in four major classes introduced as very high, high, moderate, and low

  13. Computer Simulations and Theoretical Studies of Complex Systems: from complex fluids to frustrated magnets

    Science.gov (United States)

    Choi, Eunsong

    Computer simulations are an integral part of research in modern condensed matter physics; they serve as a direct bridge between theory and experiment by systemactically applying a microscopic model to a collection of particles that effectively imitate a macroscopic system. In this thesis, we study two very differnt condensed systems, namely complex fluids and frustrated magnets, primarily by simulating classical dynamics of each system. In the first part of the thesis, we focus on ionic liquids (ILs) and polymers--the two complementary classes of materials that can be combined to provide various unique properties. The properties of polymers/ILs systems, such as conductivity, viscosity, and miscibility, can be fine tuned by choosing an appropriate combination of cations, anions, and polymers. However, designing a system that meets a specific need requires a concrete understanding of physics and chemistry that dictates a complex interplay between polymers and ionic liquids. In this regard, molecular dynamics (MD) simulation is an efficient tool that provides a molecular level picture of such complex systems. We study the behavior of Poly (ethylene oxide) (PEO) and the imidazolium based ionic liquids, using MD simulations and statistical mechanics. We also discuss our efforts to develop reliable and efficient classical force-fields for PEO and the ionic liquids. The second part is devoted to studies on geometrically frustrated magnets. In particular, a microscopic model, which gives rise to an incommensurate spiral magnetic ordering observed in a pyrochlore antiferromagnet is investigated. The validation of the model is made via a comparison of the spin-wave spectra with the neutron scattering data. Since the standard Holstein-Primakoff method is difficult to employ in such a complex ground state structure with a large unit cell, we carry out classical spin dynamics simulations to compute spin-wave spectra directly from the Fourier transform of spin trajectories. We

  14. A simulation study of capacity utilization to predict future capacity for manufacturing system sustainability

    Science.gov (United States)

    Rimo, Tan Hauw Sen; Chai Tin, Ong

    2017-12-01

    Capacity utilization (CU) measurement is an important task in a manufacturing system, especially in make-to-order (MTO) type manufacturing system with product customization, in predicting capacity to meet future demand. A stochastic discrete-event simulation is developed using ARENA software to determine CU and capacity gap (CG) in short run production function. This study focused on machinery breakdown and product defective rate as random variables in the simulation. The study found that the manufacturing system run in 68.01% CU and 31.99% CG. It is revealed that machinery breakdown and product defective rate have a direct relationship with CU. By improving product defective rate into zero defect, manufacturing system can improve CU up to 73.56% and CG decrease to 26.44%. While improving machinery breakdown into zero breakdowns will improve CU up to 93.99% and the CG decrease to 6.01%. This study helps operation level to study CU using “what-if” analysis in order to meet future demand in more practical and easier method by using simulation approach. Further study is recommended by including other random variables that affect CU to make the simulation closer with the real-life situation for a better decision.

  15. [3D Virtual Reality Laparoscopic Simulation in Surgical Education - Results of a Pilot Study].

    Science.gov (United States)

    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.

  16. The effect of simulation courseware on critical thinking in undergraduate nursing students: multi-site pre-post study.

    Science.gov (United States)

    Shin, Hyunsook; Ma, Hyunhee; Park, Jiyoung; Ji, Eun Sun; Kim, Dong Hee

    2015-04-01

    The use of simulations has been considered as opportunities for students to enhance their critical thinking (CT), but previous studies were limited because they did not provide in-depth information on the working dynamics of simulation or on the effects of the number of simulation exposures on CT. This study examined the effect of an integrated pediatric nursing simulation used in a nursing practicum on students' CT abilities and identified the effects of differing numbers of simulation exposures on CT in a multi-site environment. The study used a multi-site, pre-test, post-test design. A total of 237 nursing students at three universities enrolled in a pediatric practicum participated in this study from February to December 2013. All three schools used the same simulation courseware, including the same simulation scenarios, evaluation tools, and simulation equipment. The courseware incorporated high-fidelity simulators and standardized patients. Students at school A completed one simulation session, whereas students at schools B and C completed two and three simulation sessions, respectively. Yoon's Critical Thinking Disposition tool (2008) was used to measure students' CT abilities. The gains in students' CT scores varied according to their numbers of exposures to the simulation courseware. With a single exposure, there were no statistically significant gains in CT, whereas three exposures to the courseware produced significant gains in CT. In seven subcategories of critical thinking, three exposures to the simulation courseware produced CT gains in the prudence and intellectual eagerness subcategories, and the overall simulation experience produced CT gains in the prudence, systematicity, healthy skepticism, and intellectual eagerness subcategories. Simulation courseware may produce positive learning outcomes for prudence in nursing education. In addition, the findings from the multi-site comparative study may contribute to greater understanding of how patient

  17. A simulation study provided sample size guidance for differential item functioning (DIF) studies using short scales

    DEFF Research Database (Denmark)

    Scott, Neil W.; Fayers, Peter M.; Bottomley, Andrew

    2009-01-01

    Differential item functioning (DIF) analyses are increasingly used to evaluate health-related quality of life (HRQoL) instruments, which often include relatively short subscales. Computer simulations were used to explore how various factors including scale length affect analysis of DIF by ordinal...... logistic regression....

  18. Comparison of meaningful learning characteristics in simulated nursing practice after traditional versus computer-based simulation method: a qualitative videography study.

    Science.gov (United States)

    Poikela, Paula; Ruokamo, Heli; Teräs, Marianne

    2015-02-01

    Nursing educators must ensure that nursing students acquire the necessary competencies; finding the most purposeful teaching methods and encouraging learning through meaningful learning opportunities is necessary to meet this goal. We investigated student learning in a simulated nursing practice using videography. The purpose of this paper is to examine how two different teaching methods presented students' meaningful learning in a simulated nursing experience. The 6-hour study was divided into three parts: part I, general information; part II, training; and part III, simulated nursing practice. Part II was delivered by two different methods: a computer-based simulation and a lecture. The study was carried out in the simulated nursing practice in two universities of applied sciences, in Northern Finland. The participants in parts II and I were 40 first year nursing students; 12 student volunteers continued to part III. Qualitative analysis method was used. The data were collected using video recordings and analyzed by videography. The students who used a computer-based simulation program were more likely to report meaningful learning themes than those who were first exposed to lecture method. Educators should be encouraged to use computer-based simulation teaching in conjunction with other teaching methods to ensure that nursing students are able to receive the greatest educational benefits. Copyright © 2014 Elsevier Ltd. All rights reserved.

  19. Co-producing simulation models to inform resource management: a case study from southwest South Dakota

    Science.gov (United States)

    Miller, Brian W.; Symstad, Amy J.; Frid, Leonardo; Fisichelli, Nicholas A.; Schuurman, Gregor W.

    2017-01-01

    Simulation models can represent complexities of the real world and serve as virtual laboratories for asking “what if…?” questions about how systems might respond to different scenarios. However, simulation models have limited relevance to real-world applications when designed without input from people who could use the simulated scenarios to inform their decisions. Here, we report on a state-and-transition simulation model of vegetation dynamics that was coupled to a scenario planning process and co-produced by researchers, resource managers, local subject-matter experts, and climate change adaptation specialists to explore potential effects of climate scenarios and management alternatives on key resources in southwest South Dakota. Input from management partners and local experts was critical for representing key vegetation types, bison and cattle grazing, exotic plants, fire, and the effects of climate change and management on rangeland productivity and composition given the paucity of published data on many of these topics. By simulating multiple land management jurisdictions, climate scenarios, and management alternatives, the model highlighted important tradeoffs between grazer density and vegetation composition, as well as between the short- and long-term costs of invasive species management. It also pointed to impactful uncertainties related to the effects of fire and grazing on vegetation. More broadly, a scenario-based approach to model co-production bracketed the uncertainty associated with climate change and ensured that the most important (and impactful) uncertainties related to resource management were addressed. This cooperative study demonstrates six opportunities for scientists to engage users throughout the modeling process to improve model utility and relevance: (1) identifying focal dynamics and variables, (2) developing conceptual model(s), (3) parameterizing the simulation, (4) identifying relevant climate scenarios and management

  20. Simulation study on effects of machine imperfections in the KEK B-factory

    International Nuclear Information System (INIS)

    Koiso, Haruyo; Funakoshi, Yoshihiro

    1994-01-01

    Effects of machine imperfections in a low beta lattice with noninterleaved sextupoles are studied with computer simulations. Misalignments of quadrupoles and sextupoles significantly degrade the dynamic aperture and the vertical-to-horizontal emittance ratio. However, orbit corrections at sextupoles effectively recover both the dynamic aperture and the emittance ratio. (author)

  1. Large-scale agent-based social simulation : A study on epidemic prediction and control

    NARCIS (Netherlands)

    Zhang, M.

    2016-01-01

    Large-scale agent-based social simulation is gradually proving to be a versatile methodological approach for studying human societies, which could make contributions from policy making in social science, to distributed artificial intelligence and agent technology in computer science, and to theory

  2. The simulation study on the Nuclear Heating Reactor's power auto-control system

    International Nuclear Information System (INIS)

    Yang Zhijun; Liu Longzhi; Hu Guifen

    2000-01-01

    The power automatic control system on nuclear heating reactor (NHR) is a multi-input and multi-output non-linear system. The power automatic control system on NHR is studied by modern control theory. Through the simulation experiments, it is clear that adopting μ outer-loop and LQR inner-loop feedback, the best control results are obtained

  3. Studies on the survival of Ascaris suum eggs under laboratory and simulated field conditions

    NARCIS (Netherlands)

    Gaasenbeek, C.P.H.; Borgsteede, F.H.M.

    1998-01-01

    A series of four experiments was carried out to study the survival of Ascaris suum eggs: in a pig slurry unit on a farm, in the laboratory under anaerobic conditions and different relative humidities (rH), and under simulated field conditions. Survival of eggs in the pig slurry unit was 20% after

  4. Ergonomic study regarding sport training – Push-ups simulation and analysis

    Directory of Open Access Journals (Sweden)

    Ion S. BOROZAN

    2012-06-01

    Full Text Available Some of the most common and helpful physical exercises used in sport training are the push-ups. Their biomechanics is analyzed in the paper and the author also gives an ergonomical study of this particular exercise with a complete simulation of the process.

  5. Debriefing after High-Fidelity Simulation and Knowledge Retention: A Quasi-Experimental Study

    Science.gov (United States)

    Olson, Susan L.

    2013-01-01

    High-fidelity simulation (HFS) use in nursing education has been a frequent research topic in recent years. Previous research included studies on the use of HFS with nursing students, focusing on their feelings of self-confidence and anxiety. However, research focused specifically on the debriefing portion of HFS was limited. This quantitative,…

  6. Human Cadavers vs. Multimedia Simulation: A Study of Student Learning in Anatomy

    Science.gov (United States)

    Saltarelli, Andrew J.; Roseth, Cary J.; Saltarelli, William A.

    2014-01-01

    Multimedia and simulation programs are increasingly being used for anatomy instruction, yet it remains unclear how learning with these technologies compares with learning with actual human cadavers. Using a multilevel, quasi-experimental-control design, this study compared the effects of "Anatomy and Physiology Revealed" (APR) multimedia…

  7. A Theory for the Neural Basis of Language Part 2: Simulation Studies of the Model

    Science.gov (United States)

    Baron, R. J.

    1974-01-01

    Computer simulation studies of the proposed model are presented. Processes demonstrated are (1) verbally directed recall of visual experience; (2) understanding of verbal information; (3) aspects of learning and forgetting; (4) the dependence of recognition and understanding in context; and (5) elementary concepts of sentence production. (Author)

  8. Random-Number Generator Validity in Simulation Studies: An Investigation of Normality.

    Science.gov (United States)

    Bang, Jung W.; Schumacker, Randall E.; Schlieve, Paul L.

    1998-01-01

    The normality of number distributions generated by various random-number generators were studied, focusing on when the random-number generator reached a normal distribution and at what sample size. Findings suggest the steps that should be followed when using a random-number generator in a Monte Carlo simulation. (SLD)

  9. Molecular Dynamics Simulation Study of Carbon Dioxide, Methane, and Their Mixture in the Presence of Brine

    KAUST Repository

    Yang, Yafan; Nair, Arun Kumar Narayanan; Sun, Shuyu

    2017-01-01

    We perform molecular dynamics simulation study of CO2, methane, and their mixture in the presence of brine over a broad range of temperature (311–473 K), pressure (up to about 100 MPa), and NaCl concentration (up to about 14 wt %). The general

  10. Sensitivity analysis by experimental design and metamodelling : case study on simulation in national animal disease control

    NARCIS (Netherlands)

    Vonk Noordegraaf, A.; Nielen, M.; Kleijnen, J.P.C.

    2003-01-01

    Simulation is a frequently applied tool in the discipline of animal health economics. Application of sensitivity analysis, however, is often limited to changing only one factor at a time (OAT designs). In this study, the statistical techniques of Design of Experiments (DOE) and regression

  11. Assessing Critical Thinking Outcomes of Dental Hygiene Students Utilizing Virtual Patient Simulation: A Mixed Methods Study.

    Science.gov (United States)

    Allaire, Joanna L

    2015-09-01

    Dental hygiene educators must determine which educational practices best promote critical thinking, a quality necessary to translate knowledge into sound clinical decision making. The aim of this small pilot study was to determine whether virtual patient simulation had an effect on the critical thinking of dental hygiene students. A pretest-posttest design using the Health Science Reasoning Test was used to evaluate the critical thinking skills of senior dental hygiene students at The University of Texas School of Dentistry at Houston Dental Hygiene Program before and after their experience with computer-based patient simulation cases. Additional survey questions sought to identify the students' perceptions of whether the experience had helped develop their critical thinking skills and improved their ability to provide competent patient care. A convenience sample of 31 senior dental hygiene students completed both the pretest and posttest (81.5% of total students in that class); 30 senior dental hygiene students completed the survey on perceptions of the simulation (78.9% response rate). Although the results did not show a significant increase in mean scores, the students reported feeling that the use of virtual patients was an effective teaching method to promote critical thinking, problem-solving, and confidence in the clinical realm. The results of this pilot study may have implications to support the use of virtual patient simulations in dental hygiene education. Future research could include a larger controlled study to validate findings from this study.

  12. An Overview and Study on the Use of Games, Simulations, and Gamification in Higher Education

    Science.gov (United States)

    Wiggins, Bradley E.

    2016-01-01

    This article examines the use of both game-based learning (GBL) and gamification in tertiary education. This study focuses specifically on the use of games and/or simulations as well as familiarity with gamification strategies by communication faculty. Research questions concentrate on the rate, frequency, and usage of digital and non-digital…

  13. Irreversible colloidal agglomeration in presence of associative inhibitors: Computer simulation study

    International Nuclear Information System (INIS)

    Barcenas, Mariana; Duda, Yurko

    2007-01-01

    Monte Carlo simulation is employed to study the irreversible particle-cluster agglomeration of valence-limited colloids affected by associative inhibitors. The cluster size distribution and number of connections between colloids are analyzed as a function of density and inhibitor concentration. The influence of colloid functionality on its aggregation is discussed

  14. Large shear deformation of particle gels studied by Brownian Dynamics simulations

    NARCIS (Netherlands)

    Rzepiela, A.A.; Opheusden, van J.H.J.; Vliet, van T.

    2002-01-01

    This paper focuses on shear deformation of particle gels. Two different methods of shear deformation are discussed, namely affine and non-affine deformation, the second being novel in simulation studies of gels. Non-affine deformation resulted in a slower increase of the stress at small deformation.

  15. Effects of steering demand on lane keeping behaviour, self-reports, and physiology : A simulator study

    NARCIS (Netherlands)

    Dijksterhuis, Chris; Brookhuis, Karel A.; De Waard, Dick

    In this study a driving simulator was used to determine changes in mental effort in response to manipulations of steering demand. Changes in mental effort were assessed by using subjective effort ratings, physiology, and the standard deviation of the lateral position. Steering demand was increased

  16. A Simulation Study of Rater Agreement Measures with 2x2 Contingency Tables

    Science.gov (United States)

    Ato, Manuel; Lopez, Juan Jose; Benavente, Ana

    2011-01-01

    A comparison between six rater agreement measures obtained using three different approaches was achieved by means of a simulation study. Rater coefficients suggested by Bennet's [sigma] (1954), Scott's [pi] (1955), Cohen's [kappa] (1960) and Gwet's [gamma] (2008) were selected to represent the classical, descriptive approach, [alpha] agreement…

  17. Generalized canonical correlation analysis of matrices with missing rows : A simulation study

    NARCIS (Netherlands)

    van de Velden, Michel; Bijmolt, Tammo H. A.

    A method is presented for generalized canonical correlation analysis of two or more matrices with missing rows. The method is a combination of Carroll's (1968) method and the missing data approach of the OVERALS technique (Van der Burg, 1988). In a simulation study we assess the performance of the

  18. Studies of light collection in depolished inorganic scintillators using Monte Carlo Simulations

    International Nuclear Information System (INIS)

    Altamirano, A.; Salinas, C. J. Solano; Wahl, D.

    2009-01-01

    Scintillators are materials which emit light when energetic particles deposit energy in their volume. It is a quasi-universal requirement that the light detected in scintillator setups be maximised. The following project aims to study how the light collection is affected by surface depolishing using the simulation programs GEANT4 and LITRANI.

  19. The effect of positive and negative emotions on young drivers : A simulator study

    NARCIS (Netherlands)

    Eherenfreund-Hager, Ahinoam; Taubman – Ben-Ari, Orit; Toledo, Tomer; Farah, H.

    2017-01-01

    The study examined the influence of affect induction on actual risk-taking behavior in a driving simulator, as well as the links between personal variables (relevance of driving to self-esteem, sensation seeking) and the level of risky driving. Eighty young drivers aged 18–21 (M = 19.24,

  20. Promoting Collaboration in Health Care Teams through Interprofessional Education: A Simulation Case Study

    Science.gov (United States)

    Ekmekci, Ozgur

    2013-01-01

    This simulation study explores how the integration of interprofessional components into health care curriculum may impact professional stereotyping and collaborative behavior in care delivery teams comprised of a physician, a registered nurse, a physician's assistant, a physical therapist, and a radiation therapist. As part of the agent-based…

  1. Large shear deformation of particle gels studied by Brownian Dynamics simulations

    NARCIS (Netherlands)

    Rzepiela, A.A.; Opheusden, van J.H.J.; Vliet, van T.

    2004-01-01

    Brownian Dynamics (BD) simulations have been performed to study structure and rheology of particle gels under large shear deformation. The model incorporates soft spherical particles, and reversible flexible bond formation. Two different methods of shear deformation are discussed, namely affine and

  2. Ionic diffusion in quartz studied by transport measurements, SIMS and atomistic simulations

    International Nuclear Information System (INIS)

    Sartbaeva, Asel; Wells, Stephen A; Redfern, Simon A T; Hinton, Richard W; Reed, Stephen J B

    2005-01-01

    Ionic diffusion in the quartz-β-eucryptite system is studied by DC transport measurements, SIMS and atomistic simulations. Transport data show a large transient increase in ionic current at the α-β phase transition of quartz (the Hedvall effect). The SIMS data indicate two diffusion processes, one involving rapid Li + motion and the other involving penetration of Al and Li atoms into quartz at the phase transition. Atomistic simulations explain why the fine microstructure of twin domain walls in quartz near the transition does not hinder Li + diffusion

  3. Lipopolysaccharide Membranes and Membrane Proteins of Pseudomonas aeruginosa Studied by Computer Simulation

    Energy Technology Data Exchange (ETDEWEB)

    Straatsma, TP

    2006-12-01

    Pseudomonas aeruginosa is a ubiquitous environmental Gram-negative bacterium with high metabolic versatility and an exceptional ability to adapt to a wide range of ecological environments, including soil, marches, coastal habitats, plant and animal tissues. Gram-negative microbes are characterized by the asymmetric lipopolysaccharide outer membrane, the study of which is important for a number of applications. The adhesion to mineral surfaces plays a central role in characterizing their contribution to the fate of contaminants in complex environmental systems by effecting microbial transport through soils, respiration redox chemistry, and ion mobility. Another important application stems from the fact that it is also a major opportunistic human pathogen that can result in life-threatening infections in many immunocompromised patients, such as lung infections in children with cystic fibrosis, bacteraemia in burn victims, urinary-tract infections in catheterized patients, hospital-acquired pneumonia in patients on respirators, infections in cancer patients receiving chemotherapy, and keratitis and corneal ulcers in users of extended-wear soft contact lenses. The inherent resistance against antibiotics which has been linked with the specific interactions in the outer membrane of P. aeruginosa makes these infections difficult to treat. Developments in simulation methodologies as well as computer hardware have enabled the molecular simulation of biological systems of increasing size and with increasing accuracy, providing detail that is difficult or impossible to obtain experimentally. Computer simulation studies contribute to our understanding of the behavior of proteins, protein-protein and protein-DNA complexes. In recent years, a number of research groups have made significant progress in applying these methods to the study of biological membranes. However, these applications have been focused exclusively on lipid bilayer membranes and on membrane proteins in lipid

  4. A simulation study of homogeneous ice nucleation in supercooled salty water

    Science.gov (United States)

    Soria, Guiomar D.; Espinosa, Jorge R.; Ramirez, Jorge; Valeriani, Chantal; Vega, Carlos; Sanz, Eduardo

    2018-06-01

    We use computer simulations to investigate the effect of salt on homogeneous ice nucleation. The melting point of the employed solution model was obtained both by direct coexistence simulations and by thermodynamic integration from previous calculations of the water chemical potential. Using a seeding approach, in which we simulate ice seeds embedded in a supercooled aqueous solution, we compute the nucleation rate as a function of temperature for a 1.85 NaCl mol per water kilogram solution at 1 bar. To improve the accuracy and reliability of our calculations, we combine seeding with the direct computation of the ice-solution interfacial free energy at coexistence using the Mold Integration method. We compare the results with previous simulation work on pure water to understand the effect caused by the solute. The model captures the experimental trend that the nucleation rate at a given supercooling decreases when adding salt. Despite the fact that the thermodynamic driving force for ice nucleation is higher for salty water for a given supercooling, the nucleation rate slows down with salt due to a significant increase of the ice-fluid interfacial free energy. The salty water model predicts an ice nucleation rate that is in good agreement with experimental measurements, bringing confidence in the predictive ability of the model. We expect that the combination of state-of-the-art simulation methods here employed to study ice nucleation from solution will be of much use in forthcoming numerical investigations of crystallization in mixtures.

  5. Two dimensional dopant diffusion study by scanning capacitance microscopy and TSUPREM IV process simulation

    International Nuclear Information System (INIS)

    Kim, J.; McMurray, J. S.; Williams, C. C.; Slinkman, J.

    1998-01-01

    We report the results of a 2-step two-dimensional (2D) diffusion study by Scanning Capacitance Microscopy (SCM) and 2D TSUPREM IV process simulation. A quantitative 2D dopant profile of gate-like structures consisting heavily implanted n+ regions separated by a lighter doped n-type region underneath 0.56 μm gates is measured with the SCM. The SCM is operated in the constant-change-in-capacitance mode. The 2-D SCM data is converted to dopant density through a physical model of the SCM/silicon interaction. This profile has been directly compared with 2D TSUPREM IV process simulation and used to calibrate the simulation parameters. The sample is then further subjected to an additional diffusion in a furnace for 80 minutes at 1000C. The SCM measurement is repeated on the diffused sample. This final 2D dopant profile is compared with a TSUPREM IV process simulation tuned to fit the earlier profile with no change in the parameters except the temperature and time for the additional diffusion. Our results indicate that there is still a significant disagreement between the two profiles in the lateral direction. TSUPREM IV simulation considerably underestimates the diffusion under the gate region

  6. Large-scale introduction of wind power stations in the Swedish grid: a simulation study

    Energy Technology Data Exchange (ETDEWEB)

    Larsson, L

    1978-08-01

    This report describes a simulation study on the factors to be considered if wind power were to be introduced to the south Swedish power grid on a large scale. The simulations are based upon a heuristic power generation planning model, developed for the purpose. The heuristic technique reflects the actual running strategies of a big power company with suitable accuracy. All simulations refer to certain typical days in 1976 to which all wind data and system characteristics are related. The installed amount of wind power will not be subject to optimization. All differences between planned and real wind power generation is equalized by regulation of the hydro power. The simulations made differ according to how the installed amount of wind power is handled in the power generation planning. The simulations indicate that the power system examined could well bear an introduction of wind power up to a level of 20% of the total power installed. This result is of course valid only for the days examined and does not necessarily apply to the present day structure of the system.

  7. Laboratory simulation of the magnetosphere, magnetotail reconnection and the study of field-aligned currents

    International Nuclear Information System (INIS)

    Yur, G.

    1990-01-01

    Laboratory simulation of the Earth's magnetosphere is performed. A wide plasma beam with plasma density ∼ 10 13 cm -3 , velocity ∼ 10 7 cm/s, temperature ∼ 10 eV and pulse duration ∼ 100μs simulates the solar wind plasma. An externally applied magnetic field throughout the interaction chamber is varied between -300 to +300 G to simulate the interplanetary magnet field (IMF). Detailed characterization of the flow of this plasma across the IMF shows various degrees of diamagnetism and rvec E x rvec B propagation. This magnetized plasma beam interacts with a spherical dipole magnetic field that simulates the planetary field to form a planetary type plasma sphere. Cusp structures and particle precipitations are studied with optical time exposure photographs of the simulated magnetosphere. The structure is strongly controlled by the polarity of the IMF. The global structure of the magnetosphere is measured in detail for different values of the IMF at various locations in the magnetosphere. Particularly, the magnetic field measurements in the tail reveal interesting reconnection processes and above the polar region, the structure of field aligned currents that are similar to the ones obtained from the satellites above the polar region of the Earth. The main experimental parameters are selected in such a way that, at least, MHD scaling is satisfied

  8. Study on sorption capacity of synthetic zeolite for simulated nuclide Cs+

    International Nuclear Information System (INIS)

    Wang Jinming; Yi Facheng

    2006-01-01

    For the sake of understanding the functionary order of simulated nuclide Cs + and Synthetic Zeolite (ZF), the sorption equilibrium time and sorption capacity of simulated nuclide Cs + on ZF are studied with the intermittence method. The difference of temperature, pH value, Cs + concentration and medium on sorption capacity and sorption ratio are investigated. The results show that the sorption complexion of simulated nuclide Cs + on ZF in the same concentration solution are sorption equilibrium quantity in range of 155-190 mg/g in different temperatures and that in range of 165-190 mg/g in different pH values and that in range of 120-210 mg/g in different media; and changing order of equilibrium adsorption ratio is the same to that of sorption equilibrium quantity, but their changing range are wider than that of sorption equilibrium quantity; equilibrium adsorption quantity in range of 180-380 mg/g in different concentration solutions, and changing order of equilibrium adsorption ratio is opposite to that of sorption equilibrium quantity, and more-over, their changing range are wider than that of the sorption equilibrium quantity. Sorption equilibrium time of simulated nuclide Cs + on ZF is about ten to fifteen days. So the changing range of sorption capacity of simulated nuclide Cs + on ZF with conditions effects is smaller and the sorption equilibrium time is also less and ZF preferably absorbs Cs in radiation wastes and thus consumedly reduces the effect of radwaste on the environment. (authors)

  9. Simulation as Logistic Support to Handling in the Warehouse: Case Study

    Directory of Open Access Journals (Sweden)

    Janka Šaderová

    2018-02-01

    Full Text Available Manipulation processes represent an important part of the material management in a company. These processes run inside a company and represent an integrated chain of material flow. The current situation regarding the material manipulation is evaluated using the manipulation indicators which may serve as the basis for manipulation system rationalisation designs. The present case study is focused on the determination of an appropriate number of forklift trucks in a given operation and consists of three sections. The introductory section deals with the evaluation of forklift activities while applying the selected analysis and the selected indicators. Analysis results subsequently served as a basis for the calculation. The calculated number of trucks must be properly verified; the verification should be focused on whether the given number of forklifts is actually sufficient for the performance of the current activities. The activities were verified while applying the simulation. A simulation model was created using the Technomatix Plan Simulation software.

  10. Simulation study of the discharge characteristics of silos with cohesive particles

    Science.gov (United States)

    Hund, David; Weis, Dominik; Hesse, Robert; Antonyuk, Sergiy

    2017-06-01

    In many industrial applications the silo for bulk materials is an important part of an overall process. Silos are used for instance to buffer intermediate products to ensure a continuous supply for the next process step. This study deals with the discharging behaviour of silos containing cohesive bulk solids with particle sizes in the range of 100-500 μm. In this contribution the TOMAS [1,2] model developed for stationary and non-stationary discharging of a convergent hopper is verified with experiments and simulations using the Discrete Element Method. Moreover the influence of the cohesion of the bulk solids on the discharge behaviour is analysed by the simulation. The simulation results showed a qualitative agreement with the analytical model of TOMAS.

  11. Ventilation inhomogeneity in obstructive lung diseases measured by electrical impedance tomography: a simulation study.

    Science.gov (United States)

    Schullcke, B; Krueger-Ziolek, S; Gong, B; Jörres, R A; Mueller-Lisse, U; Moeller, K

    2017-10-10

    Electrical impedance tomography (EIT) has mostly been used in the Intensive Care Unit (ICU) to monitor ventilation distribution but is also promising for the diagnosis in spontaneously breathing patients with obstructive lung diseases. Beside tomographic images, several numerical measures have been proposed to quantitatively assess the lung state. In this study two common measures, the 'Global Inhomogeneity Index' and the 'Coefficient of Variation' were compared regarding their capability to reflect the severity of lung obstruction. A three-dimensional simulation model was used to simulate obstructed lungs, whereby images were reconstructed on a two-dimensional domain. Simulations revealed that minor obstructions are not adequately recognized in the reconstructed images and that obstruction above and below the electrode plane may result in misleading values of inhomogeneity measures. EIT measurements on several electrode planes are necessary to apply these measures in patients with obstructive lung diseases in a promising manner.

  12. Feasibility Study for Installing Machine in Production Line to Avoid Particle Contamination Based on CFD Simulation

    Science.gov (United States)

    Khaokom, Adisorn; Thongsri, Jatuporn

    2017-10-01

    Ventilation system inside production line for electronic component production needs to meet the factory standard. Because it can eliminate small particles which may cause of human or machine in production as well as it can distribute the circulating air temperature uniformly. CFD is used in this research in order to study the feasibility and plan for machine layout in production line before actual installation. The simulation shows the airflow in every area inside production line. From simulation with releasing the particles from human and machine is found that this ventilation system generates airflow that makes most particles float out of the machines and no particle downs to the conveyor, it results to contamination. In addition, the simulation also shows the range of 19-26 °C air temperature that meets the factory standard. The results of this research are the parts of the data to renovate the production line to get more efficiency and proper on the production.

  13. A comparative study of MONTEBURNS and MCNPX 2.6.0 codes in ADS simulations

    International Nuclear Information System (INIS)

    Barros, Graiciany P.; Pereira, Claubia; Veloso, Maria A.F.; Velasquez, Carlos E.; Costa, Antonella L.

    2013-01-01

    The possible use of the MONTEBURNS and MCNPX 2.6.0 codes in Accelerator-driven systems (ADSs) simulations for fuel evolution description is discussed. ADSs are investigated for fuel breeding and long-lived fission product transmutation so simulations of fuel evolution have a great relevance. The burnup/depletion capability is present in both studied codes. MONTEBURNS code links Monte Carlo N-Particle Transport Code (MCNP) to the radioactive decay burnup code ORIGEN2, whereas MCNPX depletion/ burnup capability is a linked process involving steady-state flux calculations by MCNPX and nuclide depletion calculations by CINDER90. A lead-cooled accelerator-driven system fueled with thorium was simulated and the results obtained using MONTEBURNS code and the results from MCNPX 2.6.0 code were compared. The system criticality and the variation of the actinide inventory during the burnup were evaluated and the results indicate a similar behavior between the results of each code. (author)

  14. Study on the Depth, Rate, Shape, and Strength of Pulse with Cardiovascular Simulator

    Directory of Open Access Journals (Sweden)

    Ju-Yeon Lee

    2017-01-01

    Full Text Available Pulse diagnosis is important in oriental medicine. The purpose of this study is explaining the mechanisms of pulse with a cardiovascular simulator. The simulator is comprised of the pulse generating part, the vessel part, and the measurement part. The pulse generating part was composed of motor, slider-crank mechanism, and piston pump. The vessel part, which was composed with the aorta and a radial artery, was fabricated with silicon to implement pulse wave propagation. The pulse parameters, such as the depth, rate, shape, and strength, were simulated. With changing the mean pressure, the floating pulse and the sunken pulse were generated. The change of heart rate generated the slow pulse and the rapid pulse. The control of the superposition time of the reflected wave generated the string-like pulse and the slippery pulse. With changing the pulse pressure, the vacuous pulse and the replete pulse were generated. The generated pulses showed good agreements with the typical pulses.

  15. Communication: Minimum in the thermal conductivity of supercooled water: A computer simulation study

    Energy Technology Data Exchange (ETDEWEB)

    Bresme, F., E-mail: f.bresme@imperial.ac.uk [Chemical Physics Section, Department of Chemistry, Imperial College, London SW7 2AZ, United Kingdom and Department of Chemistry, Norwegian University of Science and Technology, Trondheim 7491 (Norway); Biddle, J. W.; Sengers, J. V.; Anisimov, M. A. [Institute for Physical Science and Technology, and Department of Chemical and Biomolecular Engineering, University of Maryland, College Park, Maryland 20742 (United States)

    2014-04-28

    We report the results of a computer simulation study of the thermodynamic properties and the thermal conductivity of supercooled water as a function of pressure and temperature using the TIP4P-2005 water model. The thermodynamic properties can be represented by a two-structure equation of state consistent with the presence of a liquid-liquid critical point in the supercooled region. Our simulations confirm the presence of a minimum in the thermal conductivity, not only at atmospheric pressure, as previously found for the TIP5P water model, but also at elevated pressures. This anomalous behavior of the thermal conductivity of supercooled water appears to be related to the maximum of the isothermal compressibility or the minimum of the speed of sound. However, the magnitudes of the simulated thermal conductivities are sensitive to the water model adopted and appear to be significantly larger than the experimental thermal conductivities of real water at low temperatures.

  16. Communication: Minimum in the thermal conductivity of supercooled water: A computer simulation study

    International Nuclear Information System (INIS)

    Bresme, F.; Biddle, J. W.; Sengers, J. V.; Anisimov, M. A.

    2014-01-01

    We report the results of a computer simulation study of the thermodynamic properties and the thermal conductivity of supercooled water as a function of pressure and temperature using the TIP4P-2005 water model. The thermodynamic properties can be represented by a two-structure equation of state consistent with the presence of a liquid-liquid critical point in the supercooled region. Our simulations confirm the presence of a minimum in the thermal conductivity, not only at atmospheric pressure, as previously found for the TIP5P water model, but also at elevated pressures. This anomalous behavior of the thermal conductivity of supercooled water appears to be related to the maximum of the isothermal compressibility or the minimum of the speed of sound. However, the magnitudes of the simulated thermal conductivities are sensitive to the water model adopted and appear to be significantly larger than the experimental thermal conductivities of real water at low temperatures

  17. Atomistic simulation study of deformation twinning of nanocrystalline body-centered cubic Mo

    Energy Technology Data Exchange (ETDEWEB)

    Tian, Xiaofeng [The College of Nuclear Technology and Automation Engineering, Chengdu University of Technology, Chengdu (China); Li, Dan, E-mail: txf8378@163.com [The College of Nuclear Technology and Automation Engineering, Chengdu University of Technology, Chengdu (China); Yu, You [College of Optoelectronic Technology, Chengdu University of Information Technology, Chengdu (China); You, Zhen Jiang [Australian School of Petroleum, University of Adelaide, SA 5005 (Australia); Li, Tongye [The National Key Laboratory of Nuclear Fuel and Materials, Nuclear Power Institute of China, Chengdu (China); Ge, Liangquan [The College of Nuclear Technology and Automation Engineering, Chengdu University of Technology, Chengdu (China)

    2017-04-06

    Deformation twinning of nanocrystalline body-centered cubic Mo was studied using molecular dynamics simulations, and the effects of grain sizes and temperatures on the deformation were evaluated. With small grain size, grain rotation accompanying grain growth was found to play important role in nanocrystalline Mo during tensile deformation. Additionally, grain rotation and the deformation controlled by GB-mediated processes induce to the difficulty of creating crack. Twin was formed by successive emission of twinning partials from grain boundaries in small grain size systems. However, the twin mechanisms of GB splitting and overlapping of two extended dislocations were also found in larger size grain. Twin induced crack tips were observed in our simulation, and this confirmed the results of previous molecular dynamics simulations. At higher temperatures, GB activities can be thermally activated, resulting in suppression of twinning tendency and improvement of ductility of nanocrystalline Mo.

  18. On a simulation study for reliable and secured smart grid communications

    Science.gov (United States)

    Mallapuram, Sriharsha; Moulema, Paul; Yu, Wei

    2015-05-01

    Demand response is one of key smart grid applications that aims to reduce power generation at peak hours and maintain a balance between supply and demand. With the support of communication networks, energy consumers can become active actors in the energy management process by adjusting or rescheduling their electricity usage during peak hours based on utilities pricing incentives. Nonetheless, the integration of communication networks expose the smart grid to cyber-attacks. In this paper, we developed a smart grid simulation test-bed and designed evaluation scenarios. By leveraging the capabilities of Matlab and ns-3 simulation tools, we conducted a simulation study to evaluate the impact of cyber-attacks on demand response application. Our data shows that cyber-attacks could seriously disrupt smart grid operations, thus confirming the need of secure and resilient communication networks for supporting smart grid operations.

  19. Simulation study of coal mine safety investment based on system dynamics

    Institute of Scientific and Technical Information of China (English)

    Tong Lei; Dou Yuanyuan

    2014-01-01

    To generate dynamic planning for coal mine safety investment, this study applies system dynamics to decision-making, classifying safety investments by accident type. It validates the relationship between safety investments and accident cost, by structurally analyzing the causality between safety investments and their influence factors. Our simulation model, based on Vensim software, conducts simulation anal-ysis on a series of actual data from a coalmine in Shanxi Province. Our results indicate a lag phase in safety investments, and that increasing pre-phase safety investment reduces accident costs. We found that a 24%increase in initial safety investment could help reach the target accident costs level 14 months earlier. Our simulation test included nine kinds of variation trends of accident costs brought by different investment ratios on accident prevention. We found an optimized ratio of accident prevention invest-ments allowing a mine to reach accident cost goals 4 months earlier, without changing its total investment.

  20. Study on the algorithm for Newton-Rapson iteration interpolation of NURBS curve and simulation

    Science.gov (United States)

    Zhang, Wanjun; Gao, Shanping; Cheng, Xiyan; Zhang, Feng

    2017-04-01

    In order to solve the problems of Newton-Rapson iteration interpolation method of NURBS Curve, Such as interpolation time bigger, calculation more complicated, and NURBS curve step error are not easy changed and so on. This paper proposed a study on the algorithm for Newton-Rapson iteration interpolation method of NURBS curve and simulation. We can use Newton-Rapson iterative that calculate (xi, yi, zi). Simulation results show that the proposed NURBS curve interpolator meet the high-speed and high-accuracy interpolation requirements of CNC systems. The interpolation of NURBS curve should be finished. The simulation results show that the algorithm is correct; it is consistent with a NURBS curve interpolation requirements.

  1. Simulation of Photovoltaic Power Output for Solar Integration Studies in the Southeast US

    Energy Technology Data Exchange (ETDEWEB)

    Hansen, Clifford [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States). Photovoltaic and Distributed Systems Integration Dept.; Martin, Curtis [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States). Photovoltaic and Distributed Systems Integration Dept.; Tuohy, Aidan P. [Electric Power Research Inst. (EPRI), Knoxville, TN (United States)

    2016-06-01

    We describe the method used to simulate one year of AC power at one-minute intervals for a large collection of hypothetical utility-scale photovoltaic plants of varying size, employing either fixed-tilt PV modules or single-axis tracking, and for distribution-connected photovoltaic (DPV) power systems assumed for a number of metropolitan areas. We also describe the simulation of an accompanying day-ahead forecast of hourly AC power for utility-scale plants and DPV systems such that forecast errors are consistent with errors reported for current forecasting methods. The results of these simulations are intended for use in a study that examines the possible effects of increased levels of photovoltaic (PV) generation bulk on power variability within the Tennessee Valley Authority (TVA) and Southern Company service territories.

  2. Static, rheological and mechanical properties of polymer nanocomposites studied by computer modeling and simulation.

    Science.gov (United States)

    Liu, Jun; Zhang, Liqun; Cao, Dapeng; Wang, Wenchuan

    2009-12-28

    Polymer nanocomposites (PNCs) often exhibit excellent mechanical, thermal, electrical and optical properties, because they combine the performances of both polymers and inorganic or organic nanoparticles. Recently, computer modeling and simulation are playing an important role in exploring the reinforcement mechanism of the PNCs and even the design of functional PNCs. This report provides an overview of the progress made in past decades in the investigation of the static, rheological and mechanical properties of polymer nanocomposites studied by computer modeling and simulation. Emphases are placed on exploring the mechanisms at the molecular level for the dispersion of nanoparticles in nanocomposites, the effects of nanoparticles on chain conformation and glass transition temperature (T(g)), as well as viscoelastic and mechanical properties. Finally, some future challenges and opportunities in computer modeling and simulation of PNCs are addressed.

  3. The use of SIPA 2 simulator for safety studies experience feedbacks and future developments

    International Nuclear Information System (INIS)

    Dumas, J.M.; Leteinturier, D.

    1999-01-01

    SIPA 2 experience feedbacks from the beginning of its use at IPSN in 1991 and trends for the next five years are presented. The simulator has been used for three applications: training of engineers working in safety analysis, preparation of national crisis drills, safety studies. In each application, experience feedbacks are analysed to show encountered advantages and difficulties. Trends for the next five years are: extension of the engineer training program (new training courses about normal operating conditions or about beyond design basis accidents), improvements in the validation of simulation configurations (in particular comparison with Cathare 2 new version results) increase of the simulation scope in connection with the SCAR project (taking into account the current power plant datapackage, the improvement of thermalhydraulic models, the extent of the system representation, new neutronic models and description of severe accident conditions). For each trend above, a detail of the planned actions is given. (author)

  4. Informing Hospital Change Processes through Visualization and Simulation: A Case Study at a Children's Emergency Clinic.

    Science.gov (United States)

    Persson, Johanna; Dalholm, Elisabeth Hornyánszky; Johansson, Gerd

    2014-01-01

    To demonstrate the use of visualization and simulation tools in order to involve stakeholders and inform the process in hospital change processes, illustrated by an empirical study from a children's emergency clinic. Reorganization and redevelopment of a hospital is a complex activity that involves many stakeholders and demands. Visualization and simulation tools have proven useful for involving practitioners and eliciting relevant knowledge. More knowledge is desired about how these tools can be implemented in practice for hospital planning processes. A participatory planning process including practitioners and researchers was executed over a 3-year period to evaluate a combination of visualization and simulation tools to involve stakeholders in the planning process and to elicit knowledge about needs and requirements. The initial clinic proposal from the architect was discarded as a result of the empirical study. Much general knowledge about the needs of the organization was extracted by means of the adopted tools. Some of the tools proved to be more accessible than others for the practitioners participating in the study. The combination of tools added value to the process by presenting information in alternative ways and eliciting questions from different angles. Visualization and simulation tools inform a planning process (or other types of change processes) by providing the means to see beyond present demands and current work structures. Long-term involvement in combination with accessible tools is central for creating a participatory setting where the practitioners' knowledge guides the process. © 2014 Vendome Group, LLC.

  5. A Study on Bipedal and Mobile Robot Behavior Through Modeling and Simulation

    Directory of Open Access Journals (Sweden)

    Nirmala Nirmala

    2015-05-01

    Full Text Available The purpose of this work is to study and analyze mobile robot behavior. In performing this, a framework is adopted and developed for mobile and bipedal robot. The robots are design, build, and run as proceed from the development of mechanical structure, electronics and control integration, and control software application. The behavior of those robots are difficult to be observed and analyzed qualitatively. To evaluate the design and behavior quality, modeling and simulation of robot structure and its task capability is performed. The stepwise procedure to robot behavior study is explained. Behavior cases study are experimented to bipedal robots, transporter robot and Autonomous Guided Vehicle (AGV developed at our institution. The experimentation are conducted on those robots by adjusting their dynamic properties and/or surrounding environment. Validation is performed by comparing the simulation result and the real robot execution. The simulation gives a more idealistic behavior execution rather than realistic one. Adjustments are performed to fine tuning simulation's parameters to provide a more realistic performance.

  6. 29th Workshop on Recent Developments in Computer Simulation Studies in Condensed Matter Physics

    International Nuclear Information System (INIS)

    2016-01-01

    Thirty years ago, because of the dramatic increase in the power and utility of computer simulations, The University of Georgia formed the first institutional unit devoted to the application of simulations in research and teaching: The Center for Simulational Physics. Then, as the international simulations community expanded further, we sensed the need for a meeting place for both experienced simulators and newcomers to discuss inventive algorithms and recent results in an environment that promoted lively discussion. As a consequence, the Center for Simulational Physics established an annual workshop series on Recent Developments in Computer Simulation Studies in Condensed Matter Physics. This year's highly interactive workshop was the 29th in the series marking our efforts to promote high quality research in simulational physics. The continued interest shown by the scientific community amply demonstrates the useful purpose that these meetings have served. The latest workshop was held at The University of Georgia from February 22-26, 2016. It served to mark the 30 th Anniversary of the founding of the Center for Simulational Physics. In addition, during this Workshop we celebrated the 60 th birthday of our esteemed colleague Prof. H.-Bernd Schuttler. Bernd has not only contributed to the understanding of strongly correlated electron system, but has made seminal contributions to systems biology through the introduction of modern methods of computational physics. These Proceedings provide a “status report” on a number of important topics. This on-line “volume” is published with the goal of timely dissemination of the material to a wider audience. This program was supported in part by the President's Venture Fund through the generous gifts of the University of Georgia Partners and other donors. We also wish to offer thanks to the Office of the Vice-President for Research, the Franklin College of Arts and Sciences, and the IBM Corporation for partial

  7. Simulating a base population in honey bee for molecular genetic studies

    Directory of Open Access Journals (Sweden)

    Gupta Pooja

    2012-06-01

    Full Text Available Abstract Background Over the past years, reports have indicated that honey bee populations are declining and that infestation by an ecto-parasitic mite (Varroa destructor is one of the main causes. Selective breeding of resistant bees can help to prevent losses due to the parasite, but it requires that a robust breeding program and genetic evaluation are implemented. Genomic selection has emerged as an important tool in animal breeding programs and simulation studies have shown that it yields more accurate breeding value estimates, higher genetic gain and low rates of inbreeding. Since genomic selection relies on marker data, simulations conducted on a genomic dataset are a pre-requisite before selection can be implemented. Although genomic datasets have been simulated in other species undergoing genetic evaluation, simulation of a genomic dataset specific to the honey bee is required since this species has a distinct genetic and reproductive biology. Our software program was aimed at constructing a base population by simulating a random mating honey bee population. A forward-time population simulation approach was applied since it allows modeling of genetic characteristics and reproductive behavior specific to the honey bee. Results Our software program yielded a genomic dataset for a base population in linkage disequilibrium. In addition, information was obtained on (1 the position of markers on each chromosome, (2 allele frequency, (3 χ2 statistics for Hardy-Weinberg equilibrium, (4 a sorted list of markers with a minor allele frequency less than or equal to the input value, (5 average r2 values of linkage disequilibrium between all simulated marker loci pair for all generations and (6 average r2 value of linkage disequilibrium in the last generation for selected markers with the highest minor allele frequency. Conclusion We developed a software program that takes into account the genetic and reproductive biology specific to the honey bee

  8. Simulating a base population in honey bee for molecular genetic studies.

    Science.gov (United States)

    Gupta, Pooja; Conrad, Tim; Spötter, Andreas; Reinsch, Norbert; Bienefeld, Kaspar

    2012-06-27

    Over the past years, reports have indicated that honey bee populations are declining and that infestation by an ecto-parasitic mite (Varroa destructor) is one of the main causes. Selective breeding of resistant bees can help to prevent losses due to the parasite, but it requires that a robust breeding program and genetic evaluation are implemented. Genomic selection has emerged as an important tool in animal breeding programs and simulation studies have shown that it yields more accurate breeding value estimates, higher genetic gain and low rates of inbreeding. Since genomic selection relies on marker data, simulations conducted on a genomic dataset are a pre-requisite before selection can be implemented. Although genomic datasets have been simulated in other species undergoing genetic evaluation, simulation of a genomic dataset specific to the honey bee is required since this species has a distinct genetic and reproductive biology. Our software program was aimed at constructing a base population by simulating a random mating honey bee population. A forward-time population simulation approach was applied since it allows modeling of genetic characteristics and reproductive behavior specific to the honey bee. Our software program yielded a genomic dataset for a base population in linkage disequilibrium. In addition, information was obtained on (1) the position of markers on each chromosome, (2) allele frequency, (3) χ(2) statistics for Hardy-Weinberg equilibrium, (4) a sorted list of markers with a minor allele frequency less than or equal to the input value, (5) average r(2) values of linkage disequilibrium between all simulated marker loci pair for all generations and (6) average r2 value of linkage disequilibrium in the last generation for selected markers with the highest minor allele frequency. We developed a software program that takes into account the genetic and reproductive biology specific to the honey bee and that can be used to constitute a genomic

  9. Evaluation of the optimum region for mammographic system using computer simulation to study modulation transfer functions

    International Nuclear Information System (INIS)

    Oliveira, Isaura N. Sombra; Schiable, Homero; Porcel, Naider T.; Frere, Annie F.; Marques, Paulo M.A.

    1996-01-01

    An investigation of the 'optimum region' of the radiation field considering mammographic systems is studied. Such a region was defined in previous works as the field range where the system has its best performance and sharpest images. This study is based on a correlation of two methods for evaluating radiologic imaging systems, both using computer simulation in order to determine modulation transfer functions (MTFs) due to the X-ray tube focal spot in several field orientation and locations

  10. Status of CEA design and simulation studies of 200 KWe turboelectric space power system

    International Nuclear Information System (INIS)

    Carre, F.; Proust, E.; Gervaise, F.; Schwartz, J.P.; Tilliette, Z.; Vrillon, B.

    1987-01-01

    This paper presents the updated design features of the reference 200 kWe turboelectric space generator studied in France, and comments some of the alternative options to be analyzed in the near future, concerning the reactor and the conversion system in particular. Also presented the major conclusions of the simulation studies, that have been performed to analyze the overall behavior of the reference generator, during the start up and the accidental transients

  11. A resource letter CSSMD-1: computer simulation studies by the method of molecular dynamics

    International Nuclear Information System (INIS)

    Goel, S.P.; Hockney, R.W.

    1974-01-01

    A comprehensive bibliography on computer simulation studies by the method of Molecular Dynamics is presented. The bibliography includes references to relevant literature published up to mid 1973, starting from the first paper of Alder and Wainwright, published in 1957. The procedure of the method of Molecular Dynamics, the main fields of study in which it has been used, its limitations and how these have been overcome in some cases are also discussed [pt

  12. Intraoperative Noise Increases Perceived Task Load and Fatigue in Anesthesiology Residents: A Simulation-Based Study.

    Science.gov (United States)

    McNeer, Richard R; Bennett, Christopher L; Dudaryk, Roman

    2016-02-01

    Operating rooms are identified as being one of the noisiest of clinical environments, and intraoperative noise is associated with adverse effects on staff and patient safety. Simulation-based experiments would offer controllable and safe venues for investigating this noise problem. However, realistic simulation of the clinical auditory environment is rare in current simulators. Therefore, we retrofitted our operating room simulator to be able to produce immersive auditory simulations with the use of typical sound sources encountered during surgeries. Then, we tested the hypothesis that anesthesia residents would perceive greater task load and fatigue while being given simulated lunch breaks in noisy environments rather than in quiet ones. As a secondary objective, we proposed and tested the plausibility of a novel psychometric instrument for the assessment of stress. In this simulation-based, randomized, repeated-measures, crossover study, 2 validated psychometric survey instruments, the NASA Task Load Index (NASA-TLX), composed of 6 items, and the Swedish Occupational Fatigue Inventory (SOFI), composed of 5 items, were used to assess perceived task load and fatigue, respectively, in first-year anesthesia residents. Residents completed the psychometric instruments after being given lunch breaks in quiet and noisy intraoperative environments (soundscapes). The effects of soundscape grouping on the psychometric instruments and their comprising items were analyzed with a split-plot analysis. A model for a new psychometric instrument for measuring stress that combines the NASA-TLX and SOFI instruments was proposed, and a factor analysis was performed on the collected data to determine the model's plausibility. Twenty residents participated in this study. Multivariate analysis of variance showed an effect of soundscape grouping on the combined NASA-TLX and SOFI instrument items (P = 0.003) and the comparisons of univariate item reached significance for the NASA Temporal

  13. Musculoskeletal Disorders in Ophthalmologists After Simulated Cataract Operation: A Pilot Study.

    Science.gov (United States)

    Pearce, Zachary D; Zatkin, Mathew A; Bruner, Jon

    2017-12-01

    Musculoskeletal disorders are a common problem among ophthalmologists, likely due to ergonomic challenges. Most research on the topic has been survey-based studies, which carry inherent weaknesses. To examine the frequency and pattern of musculoskeletal dysfunction induced by performing a surgical procedure and to quantify the improvement after ergonomic interventions. Ophthalmology residents from a single academic institution were invited to participate in the study on a volunteer basis. Preexisting musculoskeletal disorders; previous spinal, cervical, or shoulder surgery; or limited range of motion of the upper body or arms were exclusion criteria. The interventions consisted of a surgical simulation session and a control session, each lasting 2 hours. For the surgical simulation session, a musculoskeletal examination was performed at the beginning and end of the 2-hour session after the participants used the Eyesi Cataract Surgery Simulator (VRmagic). A musculoskeletal examination was performed by the palpatory screener (M.A.Z.) at the beginning and conclusion of the 2-hour control session, which consisted of both passive and active tasks. The musculoskeletal screener was blinded as to which session the participant was completing at the time of the examinations, as well as any musculoskeletal examination findings from before the intervention. All participants completed both sessions, but they were randomized into which session they were to complete first. Participants completed each session one after the other. Eight participants completed both sessions, and 32 musculoskeletal examinations were performed. In the surgical simulation session, after using the simulator, 5 of 8 participants had an increase in the number of spinal levels with tissue texture abnormalities, and 3 had no change. Of those in the control session, 5 participants had a decrease in the number of spinal levels with tissue texture abnormalities after a period of rest. Three participants in the

  14. Simulating radial dose of ion tracks in liquid water simulated with Geant4-DNA: A comparative study

    Czech Academy of Sciences Publication Activity Database

    Incerti, S.; Psaltaki, M.; Gillet, P.; Barberet, P.; Bardies, M.; Bernal, M. A.; Bordage, M. C.; Breton, V.; Davídková, Marie; Delage, E.; El Bitar, Z.; Francis, Z.; Guatelli, S.; Ivanchenko, A.; Ivanchenko, V.; Karamitros, M.; Lee, S. B.; Maigne, L.; Meylan, S.; Murakami, K.; Nieminen, P.; Payno, H.; Perrot, Y.; Petrovic, I.; Pham, Q. T.; Ristic-Fira, A.; Santin, G.; Sasaki, T.; Seznec, H.; Shin, J. I.; Štěpán, Václav; Tran, H. N.; Villagrasa, C.

    2014-01-01

    Roč. 333, AUG (2014), s. 92-98 ISSN 0168-583X Institutional support: RVO:61389005 Keywords : Monte-Carlo- Simulation * Tissue-Equivalent gas * heavy-ion * Alpha-Beams * Particles * Dosimetry * Protons * Models * Codes * Path Subject RIV: BO - Biophysics Impact factor: 1.124, year: 2014

  15. Anatomically detailed and large-scale simulations studying synapse loss and synchrony using NeuroBox

    Directory of Open Access Journals (Sweden)

    Markus eBreit

    2016-02-01

    Full Text Available The morphology of neurons and networks plays an important role in processing electrical and biochemical signals. Based on neuronal reconstructions, which are becoming abundantly available through databases such as NeuroMorpho.org, numerical simulations of Hodgkin-Huxley-type equations, coupled to biochemical models, can be performed in order to systematically investigate the influence of cellular morphology and the connectivity pattern in networks on the underlying function. Development in the area of synthetic neural network generation and morphology reconstruction from microscopy data has brought forth the software tool NeuGen. Coupling this morphology data (either from databases, synthetic or reconstruction to the simulation platform UG 4 (which harbors a neuroscientific portfolio and VRL-Studio, has brought forth the extendible toolbox NeuroBox. NeuroBox allows users to perform numerical simulations on hybrid-dimensional morphology representations. The code basis is designed in a modular way, such that e.g. new channel or synapse types can be added to the library. Workflows can be specified through scripts or through the VRL-Studio graphical workflow representation. Third-party tools, such as ImageJ, can be added to NeuroBox workflows. In this paper, NeuroBox is used to study the electrical and biochemical effects of synapse loss vs. synchrony in neurons, to investigate large morphology data sets within detailed biophysical simulations, and used to demonstrate the capability of utilizing high-performance computing infrastructure for large scale network simulations. Using new synapse distribution methods and Finite Volume based numerical solvers for compartment-type models, our results demonstrate how an increase in synaptic synchronization can compensate synapse loss at the electrical and calcium level, and how detailed neuronal morphology can be integrated in large-scale network simulations.

  16. Development of a portable field rainfall simulator for use in hillside vineyard runoff and erosion studies

    Science.gov (United States)

    Battany, M. C.; Grismer, M. E.

    2000-04-01

    An inexpensive, mobile field rainfall simulator and runoff plot frame were developed for use on hillside vineyards. The simulator framework and components were lightweight, readily available and easily manageable such that they can be handled by one person during transport, set-up and operation. The vineyard rainfall simulator was simpler than many of the machines in recent use for similar studies, yet offered equal or improved performance for small-plot studies. The system developed consistent sized 2·58 mm raindrops at intensities ranging from 20 to 90 mm/h. The average distribution uniformity coefficient at an intensity of 60 mm/h was 91·7%, with a deviation of only 2·2%. This coefficient was similar to the range reported for a more complex rotating disk simulator, and was notably greater than that obtained for other similar devices. The system water capacity of 40 l allowed for 1-h storm durations at 60 mm/h, usually sufficient time for commencement of erosion and runoff. The runoff plot frame was designed to be quickly installed, and to discourage sediment deposition in the routing of runoff to collect containers.

  17. Numerical simulation and field test study of desulfurization wastewater evaporation treatment through flue gas.

    Science.gov (United States)

    Deng, Jia-Jia; Pan, Liang-Ming; Chen, De-Qi; Dong, Yu-Quan; Wang, Cheng-Mu; Liu, Hang; Kang, Mei-Qiang

    2014-01-01

    Aimed at cost saving and pollution reduction, a novel desulfurization wastewater evaporation treatment system (DWETS) for handling wet flue gas desulfurization (WFGD) wastewater of a coal-fired power plant was studied. The system's advantages include simple process, and less investment and space. The feasibility of this system has been proven and the appropriate position and number of nozzles, the spray droplet size and flue gas temperature limitation have been obtained by computational fluid dynamics (CFD) simulation. The simulation results show that a longer duct, smaller diameter and higher flue gas temperature could help to increase the evaporation rate. The optimal DWETS design of Shangdu plant is 100 μm droplet sprayed by two nozzles located at the long duct when the flue gas temperature is 130 °C. Field tests were carried out based on the simulation results. The effects of running DWETS on the downstream devices have been studied. The results show that DWETS has a positive impact on ash removal efficiency and does not have any negative impact on the electrostatic precipitator (ESP), flue gas heat exchanger and WFGD. The pH values of the slurry of WFGD slightly increase when the DWETS is running. The simulation and field test of the DWETS show that it is a feasible future technology for desulfurization wastewater treatment.

  18. Simulation and experimental study on distortion of butt and T-joints using WELD PLANNER

    International Nuclear Information System (INIS)

    Sulaiman, Mohd Shahar; Manurung, Yupiter HP; Rahim, Mohammad Ridzwan Abdul Mohd; Redza, Ridhwan; Lidam, Robert Ngendang Ak.; Abas, Sunhaji Kiyai; Tham, Ghalib; Haruman, Esa; Chau, Chan Yin

    2011-01-01

    This paper investigates the capability of linear thermal elastic numerical analysis to predict the welding distortion that occurs due to GMAW process. Distortion is considered as the major stumbling block that can adversely affect the dimensional accuracy and thus lead to expensive corrective work. Hence, forecast of distortion is crucially needed and ought to be determined in advance in order to minimize the negative effects, improve the quality of welded parts and finally to reduce the production costs. In this study, the welding deformation was simulated by using relatively new FEM software WELD PLANNER developed by ESI Group. This novel Welding Simulation Solution was employed to predict welding distortion induced in butt and T-joints with thickness of 4 mm. Low carbon steel material was used for the simulation and experimental study. A series of experiments using fully automated welding process were conducted for verification purpose to measure the distortion. By comparing between the simulation and experimental results, it was found out that this program code offered fast solution analysis time in estimating weld induced distortion within acceptable accuracy

  19. Simulating large-scale pedestrian movement using CA and event driven model: Methodology and case study

    Science.gov (United States)

    Li, Jun; Fu, Siyao; He, Haibo; Jia, Hongfei; Li, Yanzhong; Guo, Yi

    2015-11-01

    Large-scale regional evacuation is an important part of national security emergency response plan. Large commercial shopping area, as the typical service system, its emergency evacuation is one of the hot research topics. A systematic methodology based on Cellular Automata with the Dynamic Floor Field and event driven model has been proposed, and the methodology has been examined within context of a case study involving the evacuation within a commercial shopping mall. Pedestrians walking is based on Cellular Automata and event driven model. In this paper, the event driven model is adopted to simulate the pedestrian movement patterns, the simulation process is divided into normal situation and emergency evacuation. The model is composed of four layers: environment layer, customer layer, clerk layer and trajectory layer. For the simulation of movement route of pedestrians, the model takes into account purchase intention of customers and density of pedestrians. Based on evacuation model of Cellular Automata with Dynamic Floor Field and event driven model, we can reflect behavior characteristics of customers and clerks at the situations of normal and emergency evacuation. The distribution of individual evacuation time as a function of initial positions and the dynamics of the evacuation process is studied. Our results indicate that the evacuation model using the combination of Cellular Automata with Dynamic Floor Field and event driven scheduling can be used to simulate the evacuation of pedestrian flows in indoor areas with complicated surroundings and to investigate the layout of shopping mall.

  20. Simulation and experimental study on distortion of butt and T-joints using WELD PLANNER

    Energy Technology Data Exchange (ETDEWEB)

    Sulaiman, Mohd Shahar; Manurung, Yupiter HP; Rahim, Mohammad Ridzwan Abdul Mohd; Redza, Ridhwan; Lidam, Robert Ngendang Ak.; Abas, Sunhaji Kiyai; Tham, Ghalib [Universiti Teknologi MARA, Kuala Lumpur (Malaysia); Haruman, Esa [Bakrie University, Jakarta (Indonesia); Chau, Chan Yin [ESI Group, Kuala Lumpur (Malaysia)

    2011-10-15

    This paper investigates the capability of linear thermal elastic numerical analysis to predict the welding distortion that occurs due to GMAW process. Distortion is considered as the major stumbling block that can adversely affect the dimensional accuracy and thus lead to expensive corrective work. Hence, forecast of distortion is crucially needed and ought to be determined in advance in order to minimize the negative effects, improve the quality of welded parts and finally to reduce the production costs. In this study, the welding deformation was simulated by using relatively new FEM software WELD PLANNER developed by ESI Group. This novel Welding Simulation Solution was employed to predict welding distortion induced in butt and T-joints with thickness of 4 mm. Low carbon steel material was used for the simulation and experimental study. A series of experiments using fully automated welding process were conducted for verification purpose to measure the distortion. By comparing between the simulation and experimental results, it was found out that this program code offered fast solution analysis time in estimating weld induced distortion within acceptable accuracy.

  1. Design and development of driving simulator scenarios for road validation studies

    Energy Technology Data Exchange (ETDEWEB)

    Dols Ruiz, J.F.

    2016-07-01

    In recent years, the number of road-based studies using driving simulators is growing significantly. This allows evaluating controlled situations that otherwise would require disproportionate observations in time and/or cost. The Institute of Design and Manufacturing (IDF) of the Polytechnic University of Valencia (UPV) has developed, in collaboration with the Engineering Research Group Highway (GIIC) of the UPV, a low cost simulator that allows rapid implementation and effectively a new methodology for validation studies of different roads through the implementation in the simulator scenarios of existing roads. This methodology allows the development of new scenarios based on the analysis of a layers-file system. Each layer includes different information from the road, such as mapping, geometry, signaling, aerial photos, etc. The creation of the simulated scenario is very fast based on the geometric design software, making it easier to consulting firms using the system that can evaluate and audit a particular route, obtaining reliable conclusions at minimal cost, even if the road is not actually built. This paper describes the basic structure of the layers generated for developing scenarios and guidelines for the implementation thereof. Finally the application of this methodology to a case of success will be described. (Author)

  2. Integrating atomistic molecular dynamics simulations, experiments and network analysis to study protein dynamics: strength in unity

    Directory of Open Access Journals (Sweden)

    Elena ePapaleo

    2015-05-01

    Full Text Available In the last years, we have been observing remarkable improvements in the field of protein dynamics. Indeed, we can now study protein dynamics in atomistic details over several timescales with a rich portfolio of experimental and computational techniques. On one side, this provides us with the possibility to validate simulation methods and physical models against a broad range of experimental observables. On the other side, it also allows a complementary and comprehensive view on protein structure and dynamics. What is needed now is a better understanding of the link between the dynamic properties that we observe and the functional properties of these important cellular machines. To make progresses in this direction, we need to improve the physical models used to describe proteins and solvent in molecular dynamics, as well as to strengthen the integration of experiments and simulations to overcome their own limitations. Moreover, now that we have the means to study protein dynamics in great details, we need new tools to understand the information embedded in the protein ensembles and in their dynamic signature. With this aim in mind, we should enrich the current tools for analysis of biomolecular simulations with attention to the effects that can be propagated over long distances and are often associated to important biological functions. In this context, approaches inspired by network analysis can make an important contribution to the analysis of molecular dynamics simulations.

  3. A GCMC simulation and experimental study of krypton adsorption/desorption hysteresis on a graphite surface.

    Science.gov (United States)

    Prasetyo, Luisa; Horikawa, Toshihide; Phadungbut, Poomiwat; Johnathan Tan, Shiliang; Do, D D; Nicholson, D

    2016-09-15

    Adsorption isotherms and isosteric heats of krypton on a highly graphitized carbon black, Carbopack F, have been studied with a combination of Monte Carlo simulation and high-resolution experiments at 77K and 87K. Our investigation sheds light on the microscopic origin of the experimentally observed, horizontal hysteresis loop in the first layer, and the vertical hysteresis-loop in the second layer, and is found to be in agreement with our recent Monte Carlo simulation study (Diao et al., 2015). From detailed analysis of the adsorption isotherm, the latter is attributed to the compression of an imperfect solid-like state in the first layer, to form a hexagonally packed, solid-like state, immediately following the first order condensation of the second layer. To ensure that capillary condensation in the confined spaces between microcrystallites of Carbopack F does not interfere with these hysteresis loops, we carried out simulations of krypton adsorption in the confined space of a wedge-shaped pore that mimics the interstices between particles. These simulations show that, up to the third layer, any such interference is negligible. Copyright © 2016 Elsevier Inc. All rights reserved.

  4. A comparative study on real lab and simulation lab in communication engineering from students' perspectives

    Science.gov (United States)

    Balakrishnan, B.; Woods, P. C.

    2013-05-01

    Over the years, rapid development in computer technology has engendered simulation-based laboratory (lab) in addition to the traditional hands-on (physical) lab. Many higher education institutions adopt simulation lab, replacing some existing physical lab experiments. The creation of new systems for conducting engineering lab activities has raised concerns among educators on the merits and shortcomings of both physical and simulation labs; at the same time, many arguments have been raised on the differences of both labs. Investigating the effectiveness of both labs is complicated, as there are multiple factors that should be considered. In view of this challenge, a study on students' perspectives on their experience related to key aspects on engineering laboratory exercise was conducted. In this study, the Visual Auditory Read and Kinetic model was utilised to measure the students' cognitive styles. The investigation was done through a survey among participants from Multimedia University, Malaysia. The findings revealed that there are significant differences for most of the aspects in physical and simulation labs.

  5. Developing a Canadian Curriculum for Simulation-Based Education in Obstetrics and Gynaecology: A Delphi Study.

    Science.gov (United States)

    Craig, Catherine; Posner, Glenn D

    2017-09-01

    As obstetrics and gynaecology (Ob/Gyn) residency training programs move towards a competence-based approach to training and assessment, the development of a national standardized simulation curriculum is essential. The primary goal of this study was to define the fundamental content for the Canadian Obstetrics and Gynecology Simulation curriculum. A modified Delphi technique was used to achieve consensus in three rounds by surveying residency program directors or their local simulation educator delegates in 16 accredited Canadian Ob/Gyn residency programs. A consensus rate of 80% was agreed upon. Survey results were collected over 11 months in 2016. Response rates for the Delphi were 50% for the first round, 81% for the second round, and 94% for the third round. The first survey resulted in 84 suggested topics. These were organized into four categories: obstetrics high acuity low frequency events, obstetrics common events, gynaecology high acuity low frequency events, and gynaecology common events. Using the modified Delphi method, consensus was reached on 6 scenarios. This study identified the content for a national simulation-based curriculum for Ob/Gyn residency training programs and is the first step in the development of this curriculum. Copyright © 2017 The Society of Obstetricians and Gynaecologists of Canada/La Société des obstétriciens et gynécologues du Canada. Published by Elsevier Inc. All rights reserved.

  6. Studies on Fracture Behavior of Epoxy/DWNT Nanocomposites by Molecular Dynamics Simulation

    Directory of Open Access Journals (Sweden)

    Shahin Shadlou

    2012-12-01

    Full Text Available The nanoscale fracture behavior of epoxy-based nanocomposites reinforced with double-walled carbon nanotube (DWNT was investigated by molecular dynamics (MD simulations technique. In order to prepare a nanocomposite model including polymer and DWNT, the exact atomic structure of epoxy was adopted as in previous experimental studies made by authors. Tersoff and Amber potential, which are well known potentials, were used for simulation of polymer and DWNT, respectively. Among different available methods to simulate the cross-linking process, a technique was adopted with closer similarity to what happens in real conditions. Therefore, when some especial atoms of monomer and hardener molecules were closer than a specific potential distance, the chemical bonds were created between them. To verify the prepared model, a pull-out simulation was carried out and the results were compared with those of previous studies. It was found that although a rather wide range for interface strength has been presented by different researchers and different techniques, the strength obtained in this study is in the middle of this range. In addition, the fracture energy obtained from the simulations for pure epoxy was compared with that of experimental results and good agreement was obtained. To evaluate the effect of nanocomposite structure at nanometer scale, DWNT was modeled in three different angles relative to the loading direction, including 0°, 45°and 90°. It was found that when DWNT is parallel with the loading direction (i.e. 90° it has the least impact on the fracture energy. The maximum fracture energy was obtained when MWNT was at 45° relative to loading direction. These results were compared with the theories provided for conventional composites.

  7. SIMULATION STUDY OF LONGITUDINAL FORCES IN THE COUPLING DEVICE OF HEAVY FREIGHT TRAINS

    Directory of Open Access Journals (Sweden)

    Józef Stokłosa

    2014-03-01

    Full Text Available On the LHS line (Broad-gauge Metallurgical Line, far out West of the railway line with a gauge of 1520 mm, heavy goods trains for a gross weight 5500 tons and a length of 850 m are operated. The article presents the results of a simulation study of the forces that occur in the automatic coupling device of SA-3 type of Russian production train consisting of 60 coal wagons of Russian construction of gross mass 91 tons each. The train moves on the 1520 mm gauge tracks curve S type (the radius of curvature of curves 300 m. Simulation studies were conducted using the Train Module of program to dynamic study multi-elements systems of Universal Mechanism UM 6.0.

  8. CFD simulations to study the effects of wall protrusions on microfluidic mixing

    Science.gov (United States)

    Sarkar, Sourav; Singh, K. K.; Shankar, V.; Shenoy, K. T.

    2015-08-01

    In this study the effects of different types of wall protrusions on microfluidic mixing are studied using computational fluid dynamics (CFD) simulations. Two new protrusions, single first bracket protrusions and double opposite first bracket protrusions (DOFBPs), are conceptualized, evaluated through CFD simulations and compared to protrusions having standard geometrical shapes, e.g. rectangular protrusions, triangular protrusions and semicircular protrusions. In the range of Reynolds numbers covered in this study, the microchannel having an opposed T-junction and DOFBPs is found to provide good mixing. A hybrid approach relying on the modification of microfluidic junctions as well as wall protrusions for enhancing microfluidic mixing is also evaluated. The microchannel based on the hybrid approach of an OA 10°-20°-165° WY-junction and DOFBPs is also found to provide very good mixing for a wide range of Reynolds numbers.

  9. Structure, dynamics, and function of the monooxygenase P450 BM-3: insights from computer simulations studies

    International Nuclear Information System (INIS)

    Roccatano, Danilo

    2015-01-01

    The monooxygenase P450 BM-3 is a NADPH-dependent fatty acid hydroxylase enzyme isolated from soil bacterium Bacillus megaterium. As a pivotal member of cytochrome P450 superfamily, it has been intensely studied for the comprehension of structure–dynamics–function relationships in this class of enzymes. In addition, due to its peculiar properties, it is also a promising enzyme for biochemical and biomedical applications. However, despite the efforts, the full understanding of the enzyme structure and dynamics is not yet achieved. Computational studies, particularly molecular dynamics (MD) simulations, have importantly contributed to this endeavor by providing new insights at an atomic level regarding the correlations between structure, dynamics, and function of the protein. This topical review summarizes computational studies based on MD simulations of the cytochrome P450 BM-3 and gives an outlook on future directions. (topical review)

  10. Properties of Confined Star-Branched and Linear Chains. A Monte Carlo Simulation Study

    International Nuclear Information System (INIS)

    Romiszowski, P.; Sikorski, A.

    2004-01-01

    A model of linear and star-branched polymer chains confined between two parallel and impenetrable surfaces was built. The polymer chains were restricted to a simple cubic lattice. Two macromolecular architectures of the chain: linear and star branched (consisted of f = 3 branches of equal length) were studied. The excluded volume was the only potential introduced into the model (the athermal system). Monte Carlo simulations were carried out using a sampling algorithm based on chain's local changes of conformation. The simulations were carried out at different confinement conditions: from light to high chain's compression. The scaling of chain's size with the chain length was studied and discussed. The influence of the confinement and the macromolecular architecture on the shape of a chain was studied. The differences in the shape of linear and star-branched chains were pointed out. (author)

  11. Implementing Occupant Behaviour in the Simulation of Building Energy Performance and Energy Flexibility: Development of Co-Simulation Framework and Case Study

    DEFF Research Database (Denmark)

    Li, Rongling; Wei, Feng; Zhao, Yang

    2017-01-01

    Occupant behaviour has a substantial impact on the prediction of building energy performance. To capture this impact, co-simulation is considered an effective approach. It is still a new method in need of more development. In this study, a co-simulation framework is established to couple Energy......Plus with Java via Functional Mock-up Interface (FMI) using the EnergyPlusToFMU software package. This method is applied to a case study of a single occupant office with control of lighting, plug load and thermostat. Two control scenarios are studied. These are occupancy and occupant behaviour based control (OC...

  12. The knock study of methanol fuel based on multi-dimensional simulation analysis

    International Nuclear Information System (INIS)

    Zhen, Xudong; Liu, Daming; Wang, Yang

    2017-01-01

    Methanol is an alternative fuel, and considered to be one of the most favorable fuels for engines. In this study, knocking combustion in a developed ORCEM (optical rapid compression and expansion machine) is studied based on the multi-dimensional simulation analysis. The LES (large-eddy simulation) models coupled with methanol chemical reaction kinetics (contains 21-species and 84-elementary reactions) is adopted to study knocking combustion. The results showed that the end-gas auto-ignition first occurred in the position near the chamber wall because of the higher temperature and pressure. The H_2O_2 species could be a good flame front indicator. OH radicals played the major role, and the HCO radicals almost could be ignored during knocking combustion. The HCO radicals generated little, so its concentration during knocking combustion almost may be ignored. The mean reaction intensity results of CH_2O, OH, H_2O_2, and CO were higher than others during knocking combustion. Finally, this paper put forward some new suggestions on the weakness in the knocking combustion researches of methanol fuel. - Highlights: • Knocking combustion of methanol was studied in a developed ORCEM. • The LES coupled with detailed chemical kinetics was adopted to simulation study. • The end-gas auto-ignition first occurred in the place near the chamber wall. • OH radical was the predominant species during knocking combustion. • The H_2O_2 species could be a good flame front indicator.

  13. A Preliminary Study on Time Projection Chamber Simulation for Fission Cross Section Measurements with Geant4

    International Nuclear Information System (INIS)

    Kim, Jong Woon; Lee, Youngouk; Kim, Jae Cheon

    2014-01-01

    We present the details of the TPC simulation with Geant4 and show the results. TPC can provide more information than a fission chamber in that it is possible to distinguish different particle types. Simulations are conducted for uranium and plutonium targets with 20MeV neutrons. The simulation results are compared with the reference and show reasonable results. This is the first phase of study for realizing a TPC in the NFS at RAON, and we have more work to do, such as applying an electric field, signal processing in the simulation, and manufacturing of a TPC. The standard in fission cross section measurement is a fission chamber. It is basically just two parallel plates separated by a few centimeters of gas. A power supply connected to the plates sets up a moderate electric field. The target is deposited onto one of the plates. When fission occurs, the fragments ionize the gas, and the electric field causes the produced electrons to drift to the opposite plate, which records the total energy deposited in the chamber. A Time Projection Chamber (TPC) is a gas ionization detector similar to a fission chamber. However, it can measure the charged particle trajectories in the active volume in three dimensions by adding several readouts on the pad plane (fission chamber has only one readout one a pad plane). The specific ionization for each particle track enables the TPC to distinguish different particle types. A TPC will be used for fission cross section measurements in the Neutron Science Facility (NSF) at RAON. As a preliminary study, we present details of TPC simulation with Geant4 and discuss the results

  14. Using clinical simulation centers to test design interventions: a pilot study of lighting and color modifications.

    Science.gov (United States)

    Gray, Whitney Austin; Kesten, Karen S; Hurst, Stephen; Day, Tama Duffy; Anderko, Laura

    2012-01-01

    The aim of this pilot study was to test design interventions such as lighting, color, and spatial color patterning on nurses' stress, alertness, and satisfaction, and to provide an example of how clinical simulation centers can be used to conduct research. The application of evidence-based design research in healthcare settings requires a transdisciplinary approach. Integrating approaches from multiple fields in real-life settings often proves time consuming and experimentally difficult. However, forums for collaboration such as clinical simulation centers may offer a solution. In these settings, identical operating and patient rooms are used to deliver simulated patient care scenarios using automated mannequins. Two identical rooms were modified in the clinical simulation center. Nurses spent 30 minutes in each room performing simulated cardiac resuscitation. Subjective measures of nurses' stress, alertness, and satisfaction were collected and compared between settings and across time using matched-pair t-test analysis. Nurses reported feeling less stressed after exposure to the experimental room than nurses who were exposed to the control room (2.22, p = .03). Scores post-session indicated a significant reduction in stress and an increase in alertness after exposure to the experimental room as compared to the control room, with significance levels below .10. (Change in stress scores: 3.44, p = .069); (change in alertness scores: 3.6, p = .071). This study reinforces the use of validated survey tools to measure stress, alertness, and satisfaction. Results support human-centered design approaches by evaluating the effect on nurses in an experimental setting.

  15. SimTCM: A human patient simulator with application to diagnostic accuracy studies of Chinese medicine.

    Science.gov (United States)

    Ferreira, Arthur de Sá; Pacheco, Antonio Guilherme

    2015-01-01

    The aim of this work is to develop and implement the SimTCM, an advanced computational model that incorporates relevant aspects from traditional Chinese medicine (TCM) theory as well as advanced statistical and epidemiological techniques for simulation and analysis of human patients. SimTCM presents five major attributes for simulation: representation of true and false profiles for any single pattern; variable count of manifestations for each manifestation profile; empirical distributions of patterns and manifestations in a disease-specific population; incorporation of uncertainty in clinical data; and the combination of the four examinations. The proposed model is strengthened by following international standards for reporting diagnostic accuracy studies, and incorporates these standards in its treatment of study population, sample size calculation, data collection of manifestation profiles, exclusion criteria and missing data handling, reference standards, randomization and blinding, and test reproducibility. Simulations using data from patients diagnosed with hypertension and post-stroke sensory-motor impairments yielded no significant differences between expected and simulated frequencies of patterns (P=0.22 or higher). Time for convergence of simulations varied from 9.90 s (9.80, 10.27) to 28.31 s (26.33, 29.52). The ratio iteration profile necessary for convergence varied between 1:1 and 5:1. This model is directly connected to forthcoming models in a large project to design and implement the SuiteTCM: ProntTCM, SciTCM, DiagTCM, StudentTCM, ResearchTCM, HerbsTCM, AcuTCM, and DataTCM. It is expected that the continuity of the SuiteTCM project enhances the evidence-based practice of Chinese medicine. The software is freely available for download at: http://suitetcm.unisuam.edu.br.

  16. A study on intelligent nuclear systems, (HASP: human acts simulation program)

    International Nuclear Information System (INIS)

    Asai, Kiyoshi; Uenaka, Junji; Kambayashi, Shaw; Higuchi, Kenji; Kume, Etsuo; Fujisaki, Masahide; Fujii, Minoru; Yokokawa, Mitsuo

    1989-03-01

    In 1987 Japan Atomic Energy Research Institute has started a ten-years program named HASP, i.e., Human Acts Simulation Program, for artificial intelligence and robotics research. In the HASP, a human-shaped robot reads and understands orders written in natural language, planning and producing a required sequence of actions, accesses to a device or an instrument recognizing its entity and dose the ordered work for plant maintenance. All of these processes including calculation of the radiation exposure of the robot are simulated by logical and numerical computations. The simulated actions of the robot in three-dimensional environments are displayed using a high speed computer for graphics. The aim of the HASP project is threefold, i.e., (1) to develop fundamental technologies for design of intelligent robots, (2) to develop technologies for automated and/or intelligent plants, (3) to provide researchers and engineers in nuclear field with basic and systematized artificial intelligence techniques. The research items are natural language understanding, goal planning by LISP calculus, pattern recognitions by neural network methods, plant modelling by solid modeller, biped robot simulations, graphic display of the robot motion, and a study of design concept of a Monte Carlo vector processor for high speed calculation of the radiation exposure. In this report research results attained in the second year of the HASP project are described. (author)

  17. Comparing brain graphs in which nodes are regions of interest or independent components: A simulation study.

    Science.gov (United States)

    Yu, Qingbao; Du, Yuhui; Chen, Jiayu; He, Hao; Sui, Jing; Pearlson, Godfrey; Calhoun, Vince D

    2017-11-01

    A key challenge in building a brain graph using fMRI data is how to define the nodes. Spatial brain components estimated by independent components analysis (ICA) and regions of interest (ROIs) determined by brain atlas are two popular methods to define nodes in brain graphs. It is difficult to evaluate which method is better in real fMRI data. Here we perform a simulation study and evaluate the accuracies of a few graph metrics in graphs with nodes of ICA components, ROIs, or modified ROIs in four simulation scenarios. Graph measures with ICA nodes are more accurate than graphs with ROI nodes in all cases. Graph measures with modified ROI nodes are modulated by artifacts. The correlations of graph metrics across subjects between graphs with ICA nodes and ground truth are higher than the correlations between graphs with ROI nodes and ground truth in scenarios with large overlapped spatial sources. Moreover, moving the location of ROIs would largely decrease the correlations in all scenarios. Evaluating graphs with different nodes is promising in simulated data rather than real data because different scenarios can be simulated and measures of different graphs can be compared with a known ground truth. Since ROIs defined using brain atlas may not correspond well to real functional boundaries, overall findings of this work suggest that it is more appropriate to define nodes using data-driven ICA than ROI approaches in real fMRI data. Copyright © 2017 Elsevier B.V. All rights reserved.

  18. A Study on Data Base for the Pyroprocessing Material Flow and MUF Uncertainty Simulation

    International Nuclear Information System (INIS)

    Sitompul, Yos Panagaman; Shin, Heesung; Han, Boyoung; Kim, Hodong

    2011-01-01

    The data base for the pyroprocessing material flow and MUF uncertainty simulation has been implemented well. There is no error in the data base processing and it is relatively fast by using OLEDB and MySQL. The important issue is the data base size. In OLEDB the data base size is limited to 2 Gb. To reduce the data base size, we give an option for users to filter the input nuclides based on their masses and activities. A simulation program called PYMUS has been developed to study the pyroprocessing material flow and MUF. In the program, there is a data base system that controls the data processing in the simulation. The data base system consists of input data base, data processing, and output data base. The data base system has been designed in such a way to be efficient. One example is using the OLEDB and MySQL. The data base system is explained in detail in this paper. The result shows that the data base system works well in the simulation

  19. Numerical simulation studies of the groundwater discharge to streams from abandoned uranium mill tailings

    International Nuclear Information System (INIS)

    Abdul, A.S.; Gillham, R.W.

    1984-06-01

    This report presents an evaluation of the results of simulation studies of groundwater discharge to streams from abandoned uranium mill tailings and the effects of this discharge on the flux of contaminants to surface water systems. In particular, a discussion of the sensitivity of subsurface discharge to specific geometirc, climatic and hydrogeologic factors is presented. Simulations were carried out using a two-dimensional numerical finite-element unsaturated-saturated flow model. A total of twenty-six simulations were made. The first twenty-four of these considered a tailings medium with homogeneous and isotropic hydraulic properties and with textural properties similar to those of sandy geological materials. In addition, two simulations were carried out for tailings materials with hydraulic properties that are similar to those of silt-loam. The results indicated that the actual quantity of subsurface discharge depends on many factors including rainfall rate and duration, surface slope, and texture. However, for the medium-fine sand material, subsurface discharge was always a significant component of the total discharge. Within the context of uranium tailings management this implies that large quantities of contaminants from subsurface sources of medium-textured tailings can be expected to be discharged to streams during stormflow events. Therefore there is reason to suspect that untreated runoff from such tailings will contain significant concentrations of contaminants for long periods of time

  20. A simulation study on the focal plane detector of the LAUE project

    International Nuclear Information System (INIS)

    Khalil, M.; Frontera, F.; Caroli, E.; Virgilli, E.; Valsan, V.

    2015-01-01

    The LAUE project, supported by the Italian Space Agency (ASI), is devoted to the development of a long focal length (even 20 m or longer) Laue lens for gamma ray astronomy between 80 and 600 keV. These lenses take advantage of Bragg diffraction to focus radiation onto a small spot drastically improving the signal to noise ratio as well as reducing the required size of the detector significantly. In this paper we present a Monte-Carlo simulation study with MEGALIB to optimize, for space applications, the detector size to achieve high detection efficiency, and to optimize the position resolution of the detector to reconstruct the Point Spread Function of the lens considered for the LAUE project. Then we will show simulations, using the SILVACO semiconductor simulation toolkit, on the optimized detector to estimate its capacitance per channel and depletion voltage. In all of the simulations, two materials were compared; a low density material (Silicon) and a high density material (Germanium). - Highlights: • The quantized Hall plateaus and Shubnikov de Haas oscillations in transition metal doped topological insulators are observed. • The evidence of a two-dimensional/layered transport of the bulk electrons is reported. • An obvious ferromagnetism in doped topological insulators is observed. • Care should be taken to pindown the transport of the topological SS in topological insulators